Method for forming metallic film and apparatus for forming the same

TECHNICAL FIELD

This invention relates to methods and apparatus for the formation of a thin noble metal film by a plasma-excited vapor phase growth process.

Moreover, this invention also relates to apparatus and methods for forming a metal film on a substrate surface by a vapor phase growth process.

Furthermore, this invention also relates to apparatus for the vapor phase growth of a thin copper film which are useful, for example, in the formation of wiring material films for use in semiconductor devices.

BACKGROUND ART

Conventionally, where it is desired to form a thin noble metal film by a vapor phase growth process, such a film has been formed by the utilization of a thermal reaction using a liquid organometallic complex, such as copper hexafluoroacetylacetonato-trimethylvinylsilane [hereinafter referred to as Cu(hfac)(tmvs)], as a raw material.

FIG. 22

is a schematic view of a conventional apparatus

500

for the vapor phase growth of a thin noble metal film. The method for forming a thin noble metal film

541

on a substrate

515

by using this apparatus

500

is described below. First of all, a liquid raw material

522

comprising Cu(hfac)(tmvs) is contained in a raw material vessel

521

, and a carrier gas comprising He gas is bubbled therethrough. The raw material evaporated by bubbling and H

2

for reduction reaction are passed through flow controllers

503

,

506

to control their flow rates, respectively, and fed into an inlet vessel

511

having a vaporizer

520

for vaporizing the raw material completely. Thereafter, the resulting precursor

513

is introduced into a reaction vessel

501

through a perforated plate

512

. A substrate

515

is disposed beneath perforated plate

512

and placed on a heater

516

. In this method, the growth rate and the film quality have been improved by controlling the flow rates of raw material

522

and H

2

for reduction reaction and the growth temperature.

However, the above-described prior art involves the following three problems.

First, since this method is based on the utilization of a thermal reaction induced on the substrate surface by heating substrate

515

, it has been difficult to improve the rate of film growth.

Secondly, the organometallic complex [e.g., Cu(hfac)(tmvs)] used as the raw material is expensive.

Thirdly, since hexafluoroacetylacetonato (hfac) and trimethylvinylsilane (tmvs) attached to Cu in Cu(hfac)(tmvs) remain in the thin Cu film (constituting thin film

541

) as impurities, it has been difficult to improve the film quality.

Moreover, where it is desired to form a metal film (e.g., a thin copper film) by a vapor phase growth process, it has been conventional practice to use a liquid organometallic complex (e.g., copper hexafluoroacetylacetonato-trimethylvinylsilane) as a raw material, dissolve the solid raw material in a solvent, vaporize it, and form a film on a substrate by the utilization of a thermal reaction.

However, since the prior art involves the formation of a film by the utilization of a thermal reaction, it has been difficult to improve the rate of film growth. Moreover, the metal complex used as the raw material is expensive. Furthermore, since hexafluoroacetylacetonato and trimethylvinylsilane attached to Cu remain in the thin Cu film as impurities, it has been difficult to improve the film quality.

Furthermore, a thin copper (Cu) film has conventionally been formed by physical film-forming processes such as vacuum evaporation, ion plating and sputtering, and a chemical vapor phase growth process (CVD process). Among others, the CVD process is widely employed because of its excellent surface covering properties.

According to a conventionally known method for the formation of a thin copper film by the CVD process, a liquid organocopper complex such as copper hexafluoroacetylacetonato-trimethylvinylsilane [hereinafter referred to as Cu(hfac)(tmvs)] is used as a raw material. This raw material is evaporated, carried to a desired surface of a substrate to be treated, and thermally decomposed to form a thin copper film on the substrate surface.

The above-described method for the formation of a thin copper metal is more specifically described with reference to

FIG. 23

illustrating an apparatus

600

for the vapor phase growth of a thin copper film. First of all, a substrate

603

to be treated is placed on a flat plate type heater

602

within a reaction vessel

601

. The gas within the aforesaid reaction vessel

601

is discharged through an exhaust pipe

604

until a predetermined degree of vacuum is reached. Subsequently, a carrier gas such as He is fed through a pipe

607

a

and bubbled through a raw material

605

[i.e., Cu(hfac)(tmvs)] contained in a raw material vessel

606

. The raw material gas obtained by bubbling and a reducing gas (e.g., hydrogen) are conducted through pipes

607

b

and

607

c

, respectively, and fed into a vaporizer

608

disposed in the upper part of the aforesaid reaction vessel

601

. The flow rates of the aforesaid raw material gas and hydrogen gas are controlled by flow controllers

609

and

610

installed in the respective pipes

607

b

and

607

c

. After the raw material gas is completely vaporized in the aforesaid vaporizer

608

, a mixed gas

613

composed of the raw material gas and hydrogen gas is discharged through a plurality of discharge orifices

612

of a discharge plate

611

disposed at the bottom of vaporizer

608

so as to travel toward the aforesaid substrate

603

placed on the aforesaid heater

602

. Since the aforesaid substrate

603

is heated to a predetermined temperature by the aforesaid flat plate type heater

602

, the aforesaid raw material, or Cu(hfac)(tmvs), is thermally decomposed on the surface of substrate

603

to form a thin copper film

614

thereon. During this film formation, the oxidation of copper is prevented by the reducing action of hydrogen. By controlling the flow rates of the aforesaid raw material and hydrogen and the heating temperature by heater

602

, the rate of copper film growth can be regulated and the film quality can be improved.

However, the above-described conventional method for the formation of a thin copper film involves the following three problems.

First, since the above-described method for the formation of a thin copper film is based on the thermal decomposition of vaporized Cu(hfac)(tmvs), it is difficult to improve the rate of film growth. Secondly, the organocopper complex [e.g., Cu(hfac)(tmvs)] used as the raw material is expensive and hence raises the cost of the resulting thin copper film. Thirdly, since hexafluoroacetylacetonato (hfac) and trimethylvinylsilane (tmvs) are incorporated into the thin copper film during its formation and remain therein as impurities, the film quality tends to be reduced.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide methods and apparatus for the formation of a thin noble metal film which can achieve a high rate of film growth, can use inexpensive raw materials, and do not allow any impurities to remain in the thin film.

Another object of the present invention is to provide methods and apparatus for the formation of a metal film which can achieve a high rate of film growth, can use inexpensive raw materials, and do not allow any impurities to remain in the film.

Still another object of the present invention is to provide an apparatus for the vapor phase growth of a thin copper film which uses inexpensive chlorine or hydrogen chloride as a raw material gas, can achieve a high rate of film growth, and can form a thin copper film of good quality containing little residual impurity and having a desired film thickness.

DISCLOSURE OF THE INVENTION

In order to accomplish the above objects, the present invention provides a method for the formation of a metal film which comprises the steps of feeding a raw material gas containing a halogen into an inlet vessel having a perforated plate made of metal; converting the raw material gas into a plasma to generate a raw material gas plasma; etching the perforated plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the perforated plate and the halogen contained in the raw material gas; converting a reducing gas into a plasma to generate a reducing gas plasma; after discharging the precursor from the inlet vessel, passing the precursor through a rotating magnetic field so as to cause the precursor to travel toward a substrate in an accelerated manner; and passing the precursor through the reducing gas plasma to remove the halogen from the precursor and directing the resulting metallic ion or neutral metal onto the substrate to form a thin metal film on the substrate.

The aforesaid metallic ion is a metal atom which has been ionized by the release of an electron or electrons, and the aforesaid neutral metal is a metal atom which has not been ionized.

The aforesaid perforated plate is preferably made of Cu or a noble metal such as Ag, Au or Pt. For example, when a perforated plate made of Cu is used, Cu

x

Cl

y

is produced as the aforesaid precursor. Consequently, Cu ions are directed onto the substrate to form a thin Cu film.

Since two plasmas (i.e., the raw material gas plasma and the reducing gas plasma) are used in this method, the reaction efficiency is markedly improved to cause an increase in rate of film growth. Moreover, since a chlorine-containing gas is used as the raw material gas and a hydrogen-containing gas is used as the reducing gas, a marked reduction in cost is achieved. Furthermore, since the reduction reaction can be accelerated independently, the amount of impurities (e.g., chlorine) remaining in the thin film can be minimized to form a thin film of high quality.

According to another embodiment of the present invention, the above objects are accomplished by providing a method for the formation of a metal film which comprises the steps of feeding a raw material gas containing a halogen into an inlet vessel having a perforated plate made of metal; converting the raw material gas into a plasma to generate a raw material gas plasma; etching the perforated plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the perforated plate and the halogen contained in the raw material gas; converting a reducing gas into a plasma to generate a reducing gas plasma; and passing the precursor through the reducing gas plasma to remove the halogen from the precursor and directing the resulting metallic ion or neutral metal onto the substrate to form a thin metal film on the substrate.

The aforesaid perforated plate is preferably made of Cu or a noble metal such as Ag, Au or Pt. For example, when a perforated plate made of Cu is used, Cu

x

Cl

y

is produced as the aforesaid precursor. Consequently, Cu ions are directed onto the substrate to form a thin Cu film.

In order to generate the aforesaid reducing gas plasma, there may be used an electrode to which high-frequency electric power is applied. For example, the precursor diffusing toward the aforesaid substrate may be reduced by disposing an electrode opposite to the substrate and generating a plasma all over the electrode.

Since two plasmas (i.e., the raw material gas plasma and the reducing gas plasma) are used in this method, the reaction efficiency is markedly improved to cause an increase in rate of film growth. Moreover, since a halogen-containing gas is used as the raw material gas and a hydrogen-containing gas is used as the reducing gas, a marked reduction in cost is achieved. Furthermore, since the reduction reaction can be accelerated independently, the amount of impurities (e.g., chlorine) remaining in the thin film can be minimized to form a thin film of high quality.

According to still another embodiment of the present invention, there is provided a method for the formation of a metal film which comprises the steps of feeding a raw material gas containing a halogen into an inlet vessel having a perforated plate made of metal; converting the raw material gas into a plasma to generate a raw material gas plasma; etching the perforated plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the perforated plate and the halogen contained in the raw material gas; producing an atomic reducing gas between the perforated plate and a substrate by heating a reducing gas to a high temperature; and, after discharging the precursor from the inlet vessel, passing the precursor through the atomic reducing gas to remove the halogen from the precursor and directing the resulting metallic ion or neutral metal onto the substrate to form a thin metal film on the substrate.

According to this method, the reaction efficiency is markedly improved to cause an increase in rate of film growth. Moreover, since a halogen-containing gas is used as the raw material gas and a hydrogen-containing gas is used as the reducing gas, a marked reduction in cost is achieved. Furthermore, since the reduction reaction can be accelerated independently, the amount of impurities (e.g., chlorine) remaining in the thin film can be minimized to form a thin film of high quality.

According to a further embodiment of the present invention, there is provided a method for the formation of a metal film which comprises the steps of bringing a raw material gas containing a halogen into contact with a hot metallic filament and thereby etching the filament with the raw material gas to produce a precursor composed of the metallic component contained in the filament and the halogen contained in the raw material gas; producing an atomic reducing gas by heating a reducing gas to a high temperature; and passing the precursor through the atomic reducing gas to remove the halogen from the precursor and directing the resulting metallic ion or neutral metal onto a substrate to form a thin metal film on the substrate.

According to the above-described method, the reaction efficiency is markedly improved to cause an increase in rate of film growth. Moreover, since a halogen-containing gas is used as the raw material gas and a hydrogen-containing gas is used as the reducing gas, a marked reduction in cost is achieved. Furthermore, since the reduction reaction can be accelerated independently, the amount of impurities (e.g., chlorine) remaining in the thin film can be minimized to form a thin film of high quality.

According to still a further embodiment of the present invention, there is provided a method for the formation of a metal film which comprises the steps of bringing a raw material gas containing a halogen into contact with a hot metallic filament and thereby etching the filament with the raw material gas to produce a precursor composed of the metallic component contained in the filament and the halogen contained in the raw material gas; utilizing high-frequency electric power for the purpose of converting a reducing gas into a plasma to generate a reducing gas plasma; and passing the precursor through the reducing gas plasma to remove the halogen from the precursor and directing the resulting metallic ion or neutral metal onto a substrate to form a thin metal film on the substrate.

According to the above-described method, the reaction efficiency is markedly improved to cause an increase in rate of film growth. Moreover, since a halogen-containing gas is used as the raw material gas and a hydrogen-containing gas is used as the reducing gas, a marked reduction in cost is achieved. Furthermore, since the reduction reaction can be accelerated independently, the amount of impurities (e.g., chlorine) remaining in the thin film can be minimized to form a thin film of high quality.

In the methods for forming a metal film in accordance with the present invention, a halogen gas, a hydrogen halide gas, or a mixed gas composed of these gases is used as the aforesaid raw material gas. For example, there may be used fluorine gas, chlorine gas, bromine gas, iodine gas, and hydrogen halide gases formed by the combination of these halogens with hydrogen. Among these gases, hydrogen chloride gas has higher reaction efficiency than chlorine gas. consequently, the use of hydrogen chloride gas can decrease the amount of reducing gas used and hence cause a reduction in cost.

Moreover, the above-described steps extending from the feeding of a raw material gas to the production of a precursor may be replace by a method comprising the step of bubbling a carrier gas (e.g., He) through a liquid organometallic complex to evaporate it, and the step of vaporizing the evaporated organometallic complex in a vaporizer or the like and introducing the resulting vapor into the reaction vessel.

According to these methods, the reducing gas plasma decomposes the impurities (e.g., halogen compounds and carbon compounds) contained in the raw material gas, the amount of impurities remaining in the thin metal film can be reduced.

According to the present invention, there is also provided an apparatus for the formation of a metal film which comprises an inlet vessel equipped with a metallic perforated plate having discharge orifices bored therethrough and adapted to receive a raw material gas in its internal volume; a first plasma generator for converting the raw material gas received in the inlet vessel into a plasma and thereby generating a raw material gas plasma; a reaction vessel housing the inlet vessel and a substrate; a rotating magnetic field generator for creating a rotating magnetic field between the perforated plate and the substrate; and a second plasma generator for generating a plasma from a reducing gas fed into the reaction vessel.

As the aforesaid rotating magnetic field generator, there may be used, for example, a device comprising a rotating magnetic field coil disposed on the side of the reaction vessel, and a power supply for passing a high electric current through the rotating magnetic field coil.

According to another embodiment of the present invention, there is provided an apparatus for the formation of a metal film which comprises an inlet vessel equipped with a metallic perforated plate having discharge orifices bored therethrough and adapted to receive a raw material gas in its internal volume; a first plasma generator for converting the raw material gas received in the inlet vessel into a plasma and thereby generating a raw material gas plasma; a reaction vessel housing the inlet vessel and a substrate; and a meshlike, ladderlike or comblike electrode for generating a plasma from a reducing gas fed into the reaction vessel by applying high-frequency electric power thereto.

By providing the electrode surface with holes or openings, the flux of the precursor can be subjected to a reduction reaction uniformly, without preventing the precursor from traveling toward the substrate.

According to still another embodiment of the present invention, there is provided an apparatus for the formation of a metal film which comprises an inlet vessel equipped with a metallic perforated plate having discharge orifices bored therethrough and adapted to receive a raw material gas in its internal volume; a plasma generator for converting the raw material gas received in the inlet vessel into a plasma and thereby generating a raw material gas plasma; a reaction vessel housing the inlet vessel and a substrate; and a reducing gas heating device for heating a reducing gas fed into the reaction vessel.

As the aforesaid reducing gas heating device, there may preferably be used, for example, a tungsten filament heated to a high temperature by passing a high electric current therethrough. When a reducing gas is made to flow through the filament, an atomic reducing gas is produced.

According to a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film which comprises a precursor feeding device for bringing a raw material gas into contact with a hot metallic filament to produce a precursor and feeding the precursor into a reaction vessel; the reaction vessel housing a substrate; and a reducing gas heating device for heating a reducing gas fed into the reaction vessel.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film which comprises a precursor feeding device for bubbling a carrier gas through a liquid organometallic complex, vaporizing the organometallic complex, producing a precursor from the vaporized organometallic complex, and feeding the precursor into a reaction vessel; the reaction vessel housing a substrate; a rotating magnetic field generator for creating a rotating magnetic field in a space above the substrate; and a second plasma generator for generating a plasma from a reducing gas fed into the reaction vessel.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film which comprises a precursor feeding device for bubbling a carrier gas through a liquid organometallic complex, vaporizing the organometallic complex, producing a precursor from the vaporized organometallic complex, and feeding the precursor into a reaction vessel; the reaction vessel housing a substrate; and a meshlike, ladderlike or comblike electrode for generating a plasma from a reducing gas fed into the reaction vessel by applying high-frequency electric power thereto.

By employing these methods and apparatus for the formation of a metal film in accordance with the present invention, a thin metal film of high quality showing no precipitation of impurities can be rapidly formed at low cost.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; second plasma generating means for converting a hydrogen-containing reducing gas within the chamber into a plasma to generate a reducing gas plasma; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor is passed through the reducing gas plasma within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; and second plasma generating means for converting a hydrogen-containing reducing gas within the chamber into a plasma to generate a reducing gas plasma; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the reducing gas plasma to remove chlorine from the precursor by reduction, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; second plasma generating means for converting a hydrogen-containing reducing gas within the chamber into a plasma to generate a reducing gas plasma; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the reducing gas plasma to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor is passed through the atomic reducing gas within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; and reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the atomic reducing gas to remove chlorine from the precursor by reduction, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the atomic reducing gas within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising precursor feeding means for bringing a chlorine-containing raw material gas into contact with a hot metallic filament to produce a precursor within a chamber housing a substrate, the precursor being composed of the metallic component contained in the metallic filament and the chlorine contained in the raw material gas; reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor is passed through the atomic reducing gas within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate.

In these apparatus, the discharge plate or metallic filament may be made of copper, so that Cu

x

Cl

y

is produced as the aforesaid precursor. Moreover, the discharge plate may be made of copper and the predetermined temperature to which the discharge plate is heated by the discharge plate heating means may be in the range of 200 to 800° C. Furthermore, the discharge plate heating means may comprise means for heating the discharge plate by introducing a rare gas into the inlet vessel, using the first plasma generating means to generate a rare gas plasma, and applying a voltage so as to cause the rare gas component ion to collide with the discharge plate.

In this case, the predetermined temperature is preferably 600° C. When Cu

x

Cl

y

is produced as the aforesaid precursor, the predetermined temperature to which the chamber is heated by the chamber heating means is preferably about 200° C. In addition to Cu, Ag, Au, Pt, Ti, W and the like may be used for the discharge plate or metallic filament. As the raw material gas, there may be used chlorine gas, hydrogen chloride gas or a mixed gas composed of these gases.

In order to accomplish the above objects, the present invention also provides a method for the formation of a metal film which comprises reacting chlorine with a metallic plate within a chamber to produce a precursor composed of a metallic component and chlorine, removing chlorine from the precursor by reduction, and directing the resulting metallic ion onto a substrate within the chamber to form a metal film on the substrate, the method being characterized in that the chamber is heated to a predetermined temperature so as to prevent the precursor from depositing on the inner wall of the chamber.

In order to accomplish the above objects, the present invention also provides a method for the formation of a metal film which comprises reacting chlorine with a metallic plate within a chamber to produce a precursor composed of a metallic component and chlorine, removing chlorine from the precursor by reduction, and directing the resulting metallic ion onto a substrate within the chamber to form a metal film on the substrate, the method being characterized in that the metallic plate is heated to a predetermined temperature so as to make the precursor easy to reduce.

According to another embodiment of the present invention, the above objects are accomplished by providing a method for the formation of a metal film which comprises reacting chlorine with a metallic plate within a chamber to produce a precursor composed of a metallic component and chlorine, removing chlorine from the precursor by reduction, and directing the resulting metallic ion onto a substrate within the chamber to form a metal film on the substrate, the method being characterized in that the chamber is heated to a predetermined temperature so as to prevent the precursor from depositing on the inner wall of the chamber and, moreover, the metallic plate is heated to a predetermined temperature so as to make the precursor easy to reduce.

In these methods, the metallic plate may be made of copper, so that Cu

x

Cl

y

is produced as the aforesaid precursor.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; second plasma generating means for converting a hydrogen-containing reducing gas within the chamber into a plasma to generate a reducing gas plasma; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor is passed through the reducing gas plasma within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate. Thus, the precursor is prevented from depositing on the inner wall of the chamber. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, the necessity of cleaning the inside of the chamber periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; and second plasma generating means for converting a hydrogen-containing reducing gas within the chamber into a plasma to generate a reducing gas plasma; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the reducing gas plasma to remove chlorine from the precursor by reduction, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate. Thus, a monomeric precursor which can be easily reduced tends to be produced. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, chlorine can be removed by reduction in a short period of time, resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; second plasma generating means for converting a hydrogen-containing reducing gas within the chamber into a plasma to generate a reducing gas plasma; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the reducing gas plasma to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate. Thus, the precursor is prevented from depositing on the inner wall of the chamber and, moreover, a monomeric precursor which can be easily reduced tends to be produced. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, the necessity of cleaning the inside of the chamber periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost. Furthermore, chlorine can be removed by reduction in a short period of time, resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor is passed through the atomic reducing gas within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate. Thus, the precursor is prevented from depositing on the inner wall of the chamber. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, the necessity of cleaning the inside of the chamber periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; and reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the atomic reducing gas to remove chlorine from the precursor by reduction, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate. Thus, a monomeric precursor which can be easily reduced tends to be produced. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, chlorine can be removed by reduction in a short period of time, resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising an inlet vessel equipped with a metallic discharge plate having a multitude of discharge orifices bored therethrough and adapted to receive a chlorine-containing raw material gas in its internal volume; discharge plate heating means for heating the discharge plate to a predetermined temperature; a chamber housing the inlet vessel and a substrate; first plasma generating means for converting the raw material gas within the inlet vessel into a plasma to generate a raw material gas plasma, and thereby etching the discharge plate with the raw material gas plasma to produce a precursor composed of the metallic component contained in the discharge plate and the chlorine contained in the raw material gas; reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor, which has been produced by etching the heated discharge plate and is hence easy to reduce, is passed through the atomic reducing gas within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate. Thus, the precursor is prevented from depositing on the inner wall of the chamber and, moreover, a monomeric precursor which can be easily reduced tends to be produced. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, the necessity of cleaning the inside of the chamber periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost. Furthermore, chlorine can be removed by reduction in a short period of time, resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, the above objects are accomplished by providing an apparatus for the formation of a metal film, the apparatus comprising precursor feeding means for bringing a chlorine-containing raw material gas into contact with a hot metallic filament to produce a precursor within a chamber housing a substrate, the precursor being composed of the metallic component contained in the metallic filament and the chlorine contained in the raw material gas; reducing gas heating means for heating a hydrogen-containing reducing gas to a high temperature and thereby producing an atomic reducing gas within the chamber between the substrate and the discharge plate; and chamber heating means for heating the chamber to a predetermined temperature; whereby the precursor is passed through the atomic reducing gas within the chamber to remove chlorine from the precursor by reduction, without allowing the precursor to deposit on the heated inner wall of the chamber, and the resulting metallic ion is directed onto the substrate to form a metal film on the substrate. Thus, the precursor is prevented from depositing on the inner wall of the chamber. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, the necessity of cleaning the inside of the chamber periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost.

According to still a further embodiment of the present invention, there is provided a method for the formation of a metal film which comprises reacting chlorine with a metallic plate within a chamber to produce a precursor composed of a metallic component and chlorine, removing chlorine from the precursor by reduction, and directing the resulting metallic ion onto a substrate within the chamber to form a metal film on the substrate, the method being characterized in that the chamber is heated to a predetermined temperature so as to prevent the precursor from depositing on the inner wall of the chamber. Thus, the precursor is prevented from depositing on the inner wall of the chamber. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, the necessity of cleaning the inside of the chamber periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost.

According to still a further embodiment of the present invention, there is provided a method for the formation of a metal film which comprises reacting chlorine with a metallic plate within a chamber to produce a precursor composed of a metallic component and chlorine, removing chlorine from the precursor by reduction, and directing the resulting metallic ion onto a substrate within the chamber to form a metal film on the substrate, the method being characterized in that the metallic plate is heated to a predetermined temperature so as to make the precursor easy to reduce. Thus, a monomeric precursor which can be easily reduced tends to be produced. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, chlorine can be removed by reduction in a short period of time, resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, there is provided a method for the formation of a metal film which comprises reacting chlorine with a metallic plate within a chamber to produce a precursor composed of a metallic component and chlorine, removing chlorine from the precursor by reduction, and directing the resulting metallic ion onto a substrate within the chamber to form a metal film on the substrate, the method being characterized in that the chamber is heated to a predetermined temperature so as to prevent the precursor from depositing on the inner wall of the chamber and, moreover, the metallic plate is heated to a predetermined temperature so as to make the precursor easy to reduce. Thus, the precursor is prevented from depositing on the inner wall of the chamber and, moreover, a monomeric precursor which can be easily reduced tends to be produced. Consequently, a high rate of film growth can be achieved, an inexpensive raw material can be used, and an apparatus for the formation of a metal film containing no residual impurities can be obtained. Moreover, the necessity of cleaning the inside of the chamber periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost. Furthermore, chlorine can be removed by reduction in a short period of time, resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising:

a reaction vessel in which a substrate to be treated is placed;

an inlet vessel disposed within the reaction vessel and equipped with a copper discharge plate having a plurality of discharge orifices bored therethrough;

temperature control means attached to the copper discharge plate;

a raw material gas feed pipe inserted into the inlet vessel for feeding chlorine or hydrogen chloride;

plasma generating means for generating a plasma of chlorine or hydrogen chloride within the inlet vessel;

atomic reducing gas producing means for producing an atomic reducing gas within the reaction vessel, at least in the neighborhood of the substrate to be treated; and

evacuation means for evacuating any gas from the reaction vessel and the inlet vessel.

According to still a further embodiment of the present invention, there is provided an apparatus for the formation of a metal film, the apparatus comprising:

a reaction vessel in which a substrate to be treated is placed;

a raw material gas feed pipe inserted into the inlet vessel for feeding chlorine or hydrogen chloride;

a spiral tube attached to the inner end of the raw material gas feed pipe, having a raw material gas flow passage whose inner surface is made of copper, and equipped with a heating element;

atomic reducing gas producing means for producing an atomic reducing gas within the reaction vessel, at least in the neighborhood of the substrate to be treated; and

evacuation means for evacuating any gas from the reaction vessel and the raw material gas flow passage.

As specifically described above, the present invention makes it possible to achieve a high rate of film growth while using inexpensive chlorine or hydrogen chloride as a raw material gas, and to form a thin copper film of good quality containing little residual impurities and having a desired film thickness, with good reproducibility. Thus, the present invention can provide an apparatus for the vapor phase growth of a thin copper film which is useful, for example, in the formation of wiring material films for use in semiconductor devices and liquid crystal displays.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a schematic view of a plasma-excited vapor phase growth apparatus for use in a first embodiment of the present invention;

FIG. 2

is a schematic view of a plasma-excited vapor phase growth apparatus for use in a second embodiment of the present invention;

FIG. 3

is a schematic view of a plasma-excited vapor phase growth apparatus for use in a third embodiment of the present invention;

FIG. 4

is a schematic view of a plasma-excited vapor phase growth apparatus for use in a fourth embodiment of the present invention;

FIG. 5

is a plan view of a meshlike elect rode for use in the fourth embodiment of the present invention;

FIG. 6

is a plan view of a ladderlike electrode for use in the fourth embodiment of the present invention;

FIG. 7

is a plan view of a comblike electrode for use in the fourth embodiment of the present invention;

FIG. 8

is a plan view of a punching board type electrode for use in the fourth embodiment of the present invention;

FIG. 9

is a schematic view of a plasma-excited vapor phase growth apparatus for use in a fifth embodiment of the present invention;

FIG. 10

is a schematic side view of an apparatus for the formation of a metal film in accordance with a sixth embodiment of the present invention;

FIG. 11

is a schematic side view of an apparatus for the formation of a metal film in accordance with a seventh embodiment of the present invention;

FIG. 12

is a schematic side view of an apparatus for the formation of a metal film in accordance with an eighth embodiment of the present invention;

FIG. 13

is a schematic side view of an apparatus for the formation of a metal film in accordance with a ninth embodiment of the present invention;

FIG. 14

is a schematic side view of an apparatus for the formation of a metal film in accordance with a tenth embodiment of the present invention;

FIG. 15

is a schematic side view of an apparatus for the formation of a metal film in accordance with an eleventh embodiment of the present invention;

FIG. 16

is a schematic side view of an apparatus for the formation of a metal film in accordance with a twelfth embodiment of the present invention;

FIG. 17

is a schematic sectional view of an apparatus for the vapor phase growth of a thin copper film in accordance with a thirteenth embodiment of the present invention;

FIG. 18

is a plan view of the copper discharge plate incorporated in the vapor phase growth apparatus of

FIG. 17

;

FIG. 19

is a schematic sectional view of an apparatus for the vapor phase growth of a thin copper film in accordance with a fourteenth embodiment of the present invention;

FIG. 20

is a view of one form of the spiral tube incorporated in the vapor phase growth apparatus of

FIG. 19

;

FIG. 21

is a view of another form of the spiral tube incorporated in the vapor phase growth apparatus of

FIG. 19

;

FIG. 22

is a schematic view of a conventional apparatus for the vapor phase growth of a thin noble metal film; and

FIG. 23

is a schematic sectional view of a conventional apparatus for the vapor phase growth of a thin copper film.

BEST MODE FOR CARRYING OUT THE INVENTION

Various embodiments of the present invention will be specifically described hereinbelow with reference to the accompanying drawings.

[First Embodiment]

FIG. 1

is a schematic view of a plasma-excited vapor phase growth apparatus for the formation of a thin noble metal film in accordance with a first embodiment of the present invention.

This plasma-excited vapor phase growth apparatus

51

includes a reaction vessel

1

formed into the shape of a box; first and second plasma generators

52

,

53

disposed on the upper and lower sides of reaction vessel

1

; and a rotating magnetic field coil

4

,

4

disposed-on the side of reaction vessel

1

.

Moreover, an inlet vessel

11

for receiving a raw material gas

55

is disposed in the upper part of the aforesaid reaction vessel

1

. A flow controller

3

and a nozzle

2

are connected to the sidewall of inlet vessel

11

, and a perforated plate

12

made of Cu and having a plurality of holes

12

a

bored therethrough is disposed at the bottom thereof. Furthermore, rotating magnetic field coil

4

,

4

disposed on the side of reaction vessel

1

creates a rotating magnetic field in the lower part of reaction vessel

1

, and this rotating magnetic field causes a metal such as Cu to receive a force directed toward a substrate

15

and thereby travel in an accelerated manner. In the lowermost part of reaction vessel

1

, a heater

16

is disposed so as to be spaced from perforated plate

12

, and substrate

15

is placed on this heater

16

. At the lower end of reaction vessel

1

and below rotating magnetic field coil

4

, a reducing gas flow controller

6

and a reducing gas inlet nozzle

5

are disposed in order to feed a reducing gas

60

comprising hydrogen gas into the interior of reaction vessel

1

. First plasma generator

52

consists of an insulating plate

9

disposed on the top surface

58

of reaction vessel

1

, a first plasma antenna

8

disposed on insulating plate

9

, and a first plasma power supply

7

. Second plasma generator

53

has the same construction as first plasma generator

52

. The bottom wall

56

of reaction vessel

1

has an exhaust port

57

bored therethrough.

Now, the operation of plasma-excited vapor phase growth apparatus

51

having the above-described construction is described below.

First of all, Cl

2

gas used as raw material gas

55

is passed through flow controller

3

in order to control its flow rate, and then introduced into inlet vessel

11

through nozzle

2

. Subsequently, the raw material gas comprising Cl

2

gas is converted into a plasma by means of first plasma antenna

8

which is energized by first plasma power supply

7

, so that a raw material gas plasma

10

comprising Cl

2

plasma is generated within inlet vessel

11

. Since the material of perforated plate

12

contains Cu, this Cl

2

plasma actively causes an etching reaction of perforated plate

12

made of Cu, resulting in the production of a precursor (Cu

x

Cl

y

)

13

. This precursor (Cu

x

Cl

y

)

13

is discharged downward through the plurality of holes

12

a

of perforated plate

12

. Thereafter, under the action of the rotating magnetic field created by rotating magnetic field coil

4

,

4

, precursor

13

is accelerated and conveyed toward substrate

15

placed on heater

16

. Immediately before precursor

13

arrives at substrate

15

, it passes through a reducing gas plasma

14

comprising H

2

plasma produced by means of second plasma antenna

18

which is energized by second plasma power supply

19

. Thus, the aforesaid precursor

13

undergoes a reduction reaction with atomic hydrogen to form a thin Cu film

62

on substrate

15

. The extent to which this thin Cu film

62

is formed depends on the uniformity of the rotating magnetic field.

Alternatively, HCl gas may be used as the aforesaid raw material gas

55

. In this case, HCl plasma is produced as raw material gas plasma

10

, but precursor

13

produced by an etching reaction of perforated plate

12

made of Cu is Cu

x

Cl

y

. Accordingly, raw material gas

55

may comprise any gas containing chlorine, and a mixed gas composed of HCl gas and Cl

2

gas may also be used. The extent to which a thin film can be stably formed depends on the uniformity of the rotating magnetic field.

[Second Embodiment]

FIG. 2

is a schematic view of a plasma-excited vapor phase growth apparatus

65

for the formation of a thin noble metal film in accordance with a second embodiment of the present invention. Since some components of this apparatus

65

have the same structure as those of plasma-excited vapor phase growth apparatus

51

used in the above-described first embodiment, these components are designated by the same reference numerals and the explanation thereof is omitted.

Plasma-excited vapor phase growth apparatus

65

used in the second embodiment includes a reaction vessel

1

formed into the shape of a box; a first plasma generator

52

disposed on the upper side of reaction vessel

1

; and a reducing gas heating device

66

for heating a reducing gas (e.g., hydrogen gas)

55

to produce an atomic gas. When compared with plasma-excited vapor phase growth apparatus

51

used in the above-described first embodiment, this plasma-excited vapor phase growth apparatus

65

differs in having reducing gas heating device

66

.

This reducing gas heating device

66

consists of a reducing gas flow controller

6

, a reducing gas inlet nozzle

5

attached thereto, and a tungsten filament disposed within reducing gas inlet nozzle

5

. The ends of the tungsten filament are connected to a direct-current power supply

24

.

The operation of plasma-excited vapor phase growth apparatus

65

having the above-described construction is described below.

First of all, Cl

2

gas used as raw material gas

55

is passed through flow controller

3

in order to control its flow rate, and then introduced into inlet vessel

11

through nozzle

2

. Thus, the Cl

2

gas is converted into a plasma by means of plasma antenna

8

which is energized by plasma power supply

7

, so that a raw material gas plasma

10

comprising Cl

2

plasma is generated. This Cl

2

plasma actively causes an etching reaction of perforated plate

12

made of Cu, resulting in the production of a precursor (Cu

x

Cl

y

)

13

within inlet vessel

11

. This precursor (Cu

x

Cl

y

)

13

is discharged downward through the plurality of holes

12

a

of perforated plate

12

. Immediately before precursor

13

arrives at substrate

15

, a reducing gas

60

comprising H

2

gas is passed through reducing gas flow controller

6

in order to control its flow rate, tungsten filament

23

is heated to 1,800° C. by means of direct-current power supply

24

to produce an atomic reducing gas

25

comprising atomic hydrogen, and this atomic reducing gas

25

is injected into reaction vessel

1

through reducing gas inlet nozzle

5

. Thus, precursor

13

undergoes a reduction reaction with atomic hydrogen to form a thin Cu film

62

on substrate

15

.

Alternatively, HCl gas may be used as the aforesaid raw material gas

55

. In this case, HCl plasma is produced as raw material gas plasma

10

, but precursor

13

produced by an etching reaction of perforated plate

12

made of Cu is Cu

x

Cl

y

. Accordingly, raw material gas

55

may comprise any gas containing chlorine, and a mixed gas composed of HCl gas and Cl

2

gas may also be used.

Since atomic reducing gas

25

comprising atomic hydrogen can be fed simply by use of reducing gas inlet nozzle

5

which permits a relatively flexible arrangement, a film having an area up to about 50 mm×50 mm can be stably formed.

[Third Embodiment]

FIG. 3

is a schematic view of a plasma-excited vapor phase growth apparatus

70

for the formation of a thin noble metal film in accordance with a third embodiment of the present invention. Since some components of this apparatus

70

have the same structure as those of plasma-excited vapor phase growth apparatus

51

,

65

used in the above-described first and second embodiments, these components are designated by the same reference numerals and the explanation thereof is omitted.

Plasma-excited vapor phase growth apparatus

70

used in the third embodiment includes a reaction vessel

1

formed into the shape of a box; a raw material gas heating device

71

disposed in the upper part of reaction vessel

1

; and a reducing gas heating device

66

disposed in the upper part of reaction vessel

1

. When compared with plasma-excited vapor phase growth apparatus

65

used in the above-described second embodiment, this plasma-excited vapor phase growth apparatus

70

differs in having raw material gas heating device

71

.

This raw material gas heating device

71

consists of a flow controller

3

, a nozzle

2

attached thereto, and a copper filament comprising several turns of copper wire and disposed within nozzle

2

. The ends of copper filament

26

are connected to a direct-current power supply

27

.

The operation of plasma-excited vapor phase growth apparatus

70

having the above-described construction is described below.

First of all, Cl

2

gas used as raw material gas

55

is passed through flow controller

3

in order to control its flow rate, and then fed into raw material gas inlet nozzle

2

. This raw material gas inlet nozzle

2

is provided therein with copper filament

26

which has been heated to 300-600° C. by supplying an electric current from direct-current power supply

27

and passing it therethrough. Thus, the aforesaid Cl

2

gas is brought into efficient contact with copper filament

26

to produce a precursor

13

. When this precursor

13

is introduced into reaction vessel

1

through raw material gas inlet nozzle

2

, precursor

13

moves downward.

Now, a reducing gas

60

comprising H

2

gas is passed through reducing gas flow controller

6

in order to control its flow rate, and then fed into reducing gas inlet nozzle

5

. This reducing gas inlet nozzle

5

is provided therein with tungsten filament

23

. When tungsten filament

23

is heated to about 1,800° C. by supplying an electric current from direct-current power supply

24

and passing it therethrough, an atomic reducing gas

25

comprising atomic hydrogen is produced from reducing gas

60

. Immediately before precursor

13

arrives at substrate

15

, the atomic hydrogen is injected into reaction vessel

1

through reducing gas inlet nozzle

5

. Thus, the aforesaid precursor

13

undergoes a reduction reaction with the atomic hydrogen to form a thin Cu film

62

on substrate

15

.

The aforesaid raw material gas

55

may comprise any gas containing chlorine. For example, there may be used HCl gas or a mixed gas composed of HCl gas and Cl

2

gas.

Since the above-described method can feed precursor

13

and atomic hydrogen simply by use of gas nozzle

5

which permits a relatively flexible arrangement, a film having an area up to about 100 mm×100 mm can be stably formed.

[Fourth Embodiment]

FIG. 4

is a schematic view of a plasma-excited vapor phase growth apparatus

85

for the formation of a thin noble metal film in accordance with a fourth embodiment of the present invention. Since some components of this apparatus

85

have the same structure as those of plasma-excited vapor phase growth apparatus

51

used in the above-described first embodiment, these components are designated by the same reference numerals and the explanation thereof is omitted. The aforesaid plasma-excited vapor phase growth apparatus

85

is characterized by the fact that, in plasma-excited vapor phase growth apparatus

51

in accordance with the first embodiment, high-frequency electric power is utilized to generate a reducing plasma. Specifically, this apparatus

85

is constructed by eliminating rotating magnetic field coil

4

, insulating plate

17

, second plasma antenna

18

and second plasma power supply

19

from the plasma-excited vapor phase growth apparatus

51

of FIG.

1

and instead adding an electrode connected to a high-frequency power supply. No modification is made in the components associated with the production of precursor

13

, the feeding of hydrogen gas used as reducing gas

60

, and the disposition of substrate

15

.

Within reaction vessel

1

, the aforesaid plasma-excited vapor phase growth apparatus

85

includes a reducing plasma generating electrode

71

disposed between perforated plate

12

and heater

16

. It also includes a high-frequency power supply

76

, a matching transformer

75

and an electric current input terminal

73

which are all disposed on the outside of reaction vessel

1

. These high-frequency power supply

76

, matching transformer

75

and electric current input terminal

73

are connected together by coaxial cables

74

, and electric current input terminal

73

and reducing plasma generating electrode

71

are connected together by a feeder

72

.

As the aforesaid reducing plasma generating electrode

71

, an electrode in the form of a flat plate having a multitude of holes is used so that the flux of precursor

13

may not be prevented from traveling toward substrate

15

. For example, there may be used a circular meshlike electrode

77

as illustrated in FIG.

5

. This meshlike electrode

77

consists of a metal mesh

77

a

formed of woven metal wires and disposed inside, and a mesh-holding jig

77

b

for fastening the periphery of metal mesh

77

a

so as to prevent it from being frayed. This mesh-holding jig

77

b

comprises, for example, an annulus which is made of the same material as that of metal mesh

77

a

and used to fasten metal mesh

77

a

by sandwiching it from the upper and lower sides.

It is to be understood that the aforesaid reducing plasma generating electrode

71

is not limited to meshlike electrode

77

, but various types of electrodes may be used, provided that they have a shape which does not prevent the flux of precursor

13

from traveling toward substrate

15

.

For example, a ladderlike electrode

79

as illustrated in

FIG. 6

, a comblike electrode

80

as illustrated in

FIG. 7

, and a punching board type electrode

81

may preferably be used.

The aforesaid ladderlike electrode

79

is formed by arranging a pair of vertical wires

79

a

in parallel and disposing a plurality of horizontal wires

79

b

between vertical wires

79

a

,

79

a

. The aforesaid comblike electrode

80

is formed by providing two units each consisting of one vertical wire

80

a

having a plurality of horizontal wires

80

b

attached thereto, and arranging these two units in interdigitated relationship. The aforesaid punching board type electrode

81

is formed by boring a plurality of small holes

83

in a circular metallic board

82

.

In the above-described electrodes, no particular limitation is placed on the diameter and number of wires constituting metal mesh

77

a

, and the pitch of the mesh, in meshlike electrode

77

; the diameter, number and spacing of horizontal wires in ladderlike electrode

79

; the diameter, number and spacing of vertical and horizontal wires

80

a

,

80

b

, and the number of units, in comblike electrode

80

; the diameter, number and arrangement of holes bored in board

82

constituting punching board type electrode

81

; and the degree of opening of the electrode. Accordingly, the shape of the electrode may be suitably chosen according to the type of the desired reducing action.

An electrically conductive material is used for these electrodes. However, the reaction vessel has an atmosphere of chlorine, it is desirable to use stainless steel or the like for the purpose of preventing corrosion.

The operation of the above-described plasma-excited vapor phase growth apparatus

85

is described below.

The process occurring until precursor

13

is discharged through the holes

12

a

of perforated plate

12

is the same as described in connection with the first embodiment. Then, high-frequency power supply

76

applies high-frequency electric power to reducing plasma generating electrode

71

by way of matching transformer

75

and electric current input terminal

73

. Thus, a reducing gas plasma

14

comprising hydrogen plasma is generated over the entire surface of the aforesaid reducing plasma generating electrode

71

. When precursor

13

passes through the hydrogen plasma, it undergoes a reduction reaction with atomic hydrogen to form a thin Cu film

62

on substrate

15

.

[Fifth Embodiment]

FIG. 9

is a schematic view of a plasma-excited vapor phase growth apparatus

90

for the formation of a thin noble metal film in accordance with a fifth embodiment of the present invention. This apparatus

90

is based on the combination of plasma-excited vapor phase growth apparatus

85

used in the above-described fourth embodiment (see

FIG. 4

) with a convention method for feeding a raw material gas (see FIG.

10

). The components having the same structure are designated by the same reference numerals and the explanation thereof is omitted.

In the aforesaid plasma-excited vapor phase growth apparatus

90

, a raw material vessel

121

is connected to a vaporizer

120

via a flow controller

103

. Moreover, the aforesaid raw material vessel

121

is provided with a bubbling pipe for producing a vapor of liquid raw material

122

contained therein. Further more, this apparatus

90

is equipped with a device for utilizing high-frequency electric power to generate a reducing gas plasma

14

and thereby subjecting precursor

13

to a reduction reaction, as illustrated in FIG.

4

.

The operation of plasma-excited vapor phase growth apparatus

90

having the above-described construction is described below.

First of all, a liquid raw material

122

comprising, for example, copper hexafluoroacetylacetonato-trimethylvinylsilane [Cu(hfac)(tmvs)] is contained in raw material vessel

121

and a carrier gas comprising He is bubbled therethrough. Liquid raw material

122

is not limited thereto, but may comprise any desired liquid organometallic complex. The raw material evaporated by bubbling is passed through flow controller

103

to control its flow rate, and then fed into vaporizer

120

. After the aforesaid raw material is completely vaporized in vaporizer

120

, the resulting precursor

113

is introduced into the interior of reaction vessel

1

through perforated plate

112

. Now, similarly to the fourth embodiment, a reducing gas plasma

14

comprising hydrogen plasma is generated by means of high-frequency electric power. Consequently, when the aforesaid precursor

113

passes through the hydrogen plasma, precursor

113

undergoes a reduction reaction to form a thin Cu film

62

on substrate

15

.

Next, an apparatus and method for the formation of a metal film in accordance with a sixth embodiment of the present invention is described with reference to FIG.

10

.

FIG. 10

is a schematic side view of the apparatus for the formation of a metal film in accordance with the sixth embodiment of the present invention.

As illustrated in

FIG. 10

, this apparatus includes a chamber

201

made, for example, of stainless steel and formed into the shape of a box; a first plasma generating means

202

disposed on the upper side of chamber

201

; and a second plasma generating means

203

disposed on the lower side of chamber

201

. This apparatus also includes a magnetic field coil

204

disposed on the side of chamber

201

. First plasma generating means

202

consists of a first insulating plate

221

disposed on the top surface of chamber

201

, a first plasma antenna

222

disposed on first insulating plate

221

, and a first power supply

223

for energizing first plasma antenna

222

. Second plasma generating means

203

consists of a second insulating plate

224

disposed on the bottom surface of chamber

201

, a second plasma antenna

225

disposed on second insulating plate

225

, and a second power supply

226

for energizing second plasma antenna

225

.

Within chamber

201

, an inlet vessel

206

is disposed under first insulating plate

221

, and a raw material gas

205

comprising chlorine gas (Cl

2

gas) is fed into inlet vessel

206

. A flow controller

207

and a nozzle

208

are connected to the sidewall of inlet vessel

206

, and a discharge plate (or metallic plate)

209

made of Copper (Cu) is disposed at the bottom of inlet vessel

206

. This discharge plate

209

has a multitude of discharge orifices

210

bored therethrough. A support

211

is disposed near the bottom of chamber

201

and a substrate

212

is placed on this support

211

. Support

211

is heated to a predetermined temperature by a heater means (not shown). At the lower end of chamber

201

and below magnetic field coil

204

, a reducing gas flow controller

214

and a reducing gas nozzle

215

are disposed in order to feed a reducing gas

213

comprising hydrogen gas (H

2

gas) into the interior of chamber

201

. Furthermore, the bottom wall of chamber

201

has an exhaust port

227

bored therethrough.

On the other hand, the sidewall of chamber

201

is provided with a filament type heater

228

serving as a chamber heating means. By using a power supply

229

to energize this heater

228

, the sidewall of chamber

201

is heated to a predetermined temperature, for example, in the range of 200 to 600° C. It is preferable that the upper limit of the predetermined temperature is not higher than the durable temperature of chamber

201

. Since this embodiment is described in connection with chamber

201

made of stainless steel, the upper temperature limit is set at 600° C. Thus, the upper limit of the predetermined temperature may be suitably determined according to the material of chamber

201

.

Even if the precursor (Cu

x

Cl

y

) which will be described later adheres to the sidewall of chamber

201

, it will readily be vaporized because the sidewall of chamber

201

is heated to cause a rise in the vapor pressure of the precursor. Consequently, the precursor (Cu

x

Cl

y

) is prevented from depositing on the sidewall of chamber

201

. Since this embodiment is described in connection with discharge plate

209

made of Cu, the lower limit of the predetermined temperature is set at 200° C. Thus, the lower limit of the predetermined temperature may be suitably determined according to the type of the precursor produced on the basis of the material of discharge plate

209

.

In the above-described apparatus for the formation of a metal film, C

12

gas is fed into inlet vessel

206

. When electromagnetic waves are radiated into inlet vessel

206

by first plasma antenna

222

of first plasma generating means

202

, the Cl

2

gas within inlet vessel

206

is ionized to generate Cl

2

gas plasma (raw material gas plasma)

231

. This Cl

2

gas plasma

231

causes an etching reaction of discharge plate

209

made of Cu, so that a precursor (Cu

x

Cl

y

)

230

is produced. This precursor (Cu

x

Cl

y

)

230

is discharged downward through discharge orifices

210

.

On the other hand, H

2

gas is introduced into chamber

201

. When electromagnetic waves are radiated into chamber

201

by second plasma antenna

225

of second plasma generating means

203

, the H

2

gas within chamber

201

is ionized to generate H

2

gas plasma (reducing gas plasma)

232

. Owing to a rotating magnetic field created by magnetic field coil

204

, this H

2

gas plasma

232

is densely and uniformly distributed in the neighborhood of the surface of substrate

212

.

Immediately before precursor (Cu

x

Cl

y

)

230

discharged downward through discharge orifices

210

arrives at substrate

212

, it passes through H

2

gas plasma

232

. While precursor (Cu

x

Cl

y

)

230

passes through H

2

gas plasma

232

serving as a reducing gas plasma, chlorine is removed therefrom by a reduction reaction with atomic hydrogen. The resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

.

Since the sidewall of chamber

201

is heated to a predetermined temperature (e.g., 200° C.) by heater

228

, precursor (Cu

x

Cl

y

)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Consequently, precursor (Cu

x

Cl

y

)

230

is prevented from depositing on the sidewall of chamber

201

. It has been confirmed that, if the sidewall of chamber

201

has a temperature lower than the predetermined temperature (e.g., 180° C. or so), the vapor pressure of precursor (Cu

x

Cl

y

)

230

will not rise sufficiently and, therefore, precursor (Cu

x

Cl

y

)

230

will deposit on the sidewall of chamber

201

.

In the above-described apparatus for the formation of a metal film, chlorine gas (Cl

2

gas) is used as an example of raw material gas

205

. However, HCl gas may also be used. In this case, HCl gas plasma is generated as the raw material gas plasma, but precursor

230

produced by the etching of discharge plate

209

made of Cu is Cu

x

Cl

y

. Accordingly, raw material gas

205

may comprise any gas containing chlorine, and a mixed gas composed of HCl gas and Cl

2

gas may also be used. Moreover, the material of discharge plate

209

is not limited to Cu, but Ag, Au, Pt, Ti, W and the like may also be used. In this case, precursor

230

comprises a chloride of Ag, Au, Pt, Ti, W or the like, and the thin film formed on the surface of substrate

212

comprises Ag, Au, Pt, Ti, W or the like.

Since two plasmas, namely Cl

2

gas plasma (raw material gas plasma)

231

and H

2

gas plasma (reducing gas plasma)

232

, are used in the above-described apparatus for the formation of a metal film, the reaction efficiency is markedly improved to cause an increase in rate of film growth. Moreover, since chlorine gas (Cl

2

gas) is used as raw material gas

205

and a hydrogen-containing gas is used as reducing gas

213

, a marked reduction in cost is achieved. Furthermore, since the reduction reaction can be accelerated independently, the amount of impurities (e.g., chlorine) remaining in thin Cu film

233

can be minimized to form a thin Cu film

233

of high quality.

In addition, since the sidewall of chamber

201

is heated to a predetermined temperature by heater

228

, precursor (Cu

x

Cl

y

)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Thus, precursor (Cu

x

Cl

y

)

230

is prevented from depositing on the sidewall of chamber

201

. Consequently, the necessity of cleaning the inside of chamber

201

periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost.

Now, an apparatus and method for the formation of a metal film in accordance with a seventh embodiment of the present invention is described with reference to FIG.

11

.

FIG. 11

is a schematic side view of the apparatus for the formation of a metal film in accordance with the seventh embodiment of the present invention. The same components as those shown in

FIG. 10

are designated by the same reference numerals and the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film as illustrated in

FIG. 10

, the apparatus for the formation of a metal film in accordance with the seventh embodiment as illustrated in

FIG. 11

does not include the chamber heating means comprising filament type heater

228

and power supply

229

, but includes a discharge plate heating means for heating discharge plate

209

. Specifically, discharge plate (or metallic plate)

209

made of Copper (Cu) is provided at the bottom of inlet vessel

206

through the medium of an insulating member

241

. An auxiliary nozzle

242

for feeding a rare gas comprising He gas is connected to the sidewall of inlet vessel

206

. Thus, He gas is fed into inlet vessel

206

together with raw material gas

205

comprising chlorine gas (Cl

2

gas). Cl

2

gas and He gas are fed into inlet vessel

206

in a ratio of approximately 1:1. A biasing power supply

243

is connected to discharge plate

209

, so that a direct-current voltage is applied to discharge plate

209

by biasing power supply

243

.

In the above-described apparatus for the formation of a metal film, when electromagnetic waves are radiated into inlet vessel

206

by first plasma antenna

222

of first plasma generating means

202

, the Cl

2

gas and He gas within inlet vessel

206

are ionized to generate Cl

2

—He gas plasma

244

. This Cl

2

—He gas plasma

244

causes He ions to collide with discharge plate

209

to which a bias voltage is applied. Thus, discharge plate

209

is uniformly heated. As the means for heating discharge plate

209

, a heater or other means for heating discharge plate

209

directly may also be used in place of the means based on the collision of He ions.

The heating temperature of discharge plate

209

is, for example, in the range of 200 to 800° C. and preferably 600° C. It is preferable that the lower limit of the heating temperature is a temperature at which precursor (Cu

x

Cl

y

)

230

passing through discharge orifices

210

becomes a monomeric compound rather than a polymeric one. When discharge plate

209

is heated to 600° C., precursor

230

tends to be monomeric CuCl and this facilitates the reduction reaction which will be described later. The upper limit of the heating temperature depends on the material of discharge plate

209

. In the case of discharge plate

209

made of copper (Cu), the upper limit is 800° C. If the heating temperature exceeds 800° C., discharge plate

209

cannot be used because of its softening. Discharge plate

209

can be adjusted to a desired temperature by controlling the voltage applied to discharge plate

209

.

When Cl

2

—He gas plasma

244

is generated within inlet vessel

206

, the Cl

2

gas plasma causes an etching reaction of the heated discharge plate

209

made of Cu, so that a monomeric precursor (CuCl)

230

tends to be produced. The resulting precursor (CuCl)

230

is discharged downward through discharge orifices

210

of discharge plate

209

. Immediately before precursor (CuCl)

230

discharged downward through discharge orifices

210

arrives at substrate

212

, it passes through H

2

gas plasma

232

. Thus, chlorine is removed therefrom by a reduction reaction with atomic hydrogen. The resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

.

Since precursor

230

discharged downward comprises monomeric CuCl, it can readily be reduced by atomic hydrogen. Thus, chlorine is removed therefrom by reduction in a short period of time. Consequently, the resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

in a short period of time. That is, since discharge plate

209

is uniformly heated to a desired temperature by the collision of He ions, a monomeric precursor (CuCl)

230

which can readily be reduced is produced. This makes it possible to remove chlorine by reduction in a short period of time and thereby improve the rate of film growth.

Now, an apparatus and method for the formation of a metal film in accordance with an eighth embodiment of the present invention is described with reference to FIG.

12

.

FIG. 12

is a schematic side view of the apparatus for the formation of a metal film in accordance with the eighth embodiment of the present invention. The same components as those shown in

FIGS. 10 and 11

are designated by the same reference numerals and the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film as illustrated in

FIG. 11

, the apparatus for the formation of a metal film in accordance with the eighth embodiment as illustrated in

FIG. 12

includes a chamber heating means comprising a filament type heater

228

and a power supply

229

. That is, this apparatus is equipped with both the chamber heating means and the discharge plate heating means.

Thus, since the sidewall of chamber

201

is heated to a predetermined temperature (e.g., 200° C.) by heater

228

, precursor (CuCl)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Consequently, precursor (CuCl)

230

is prevented from depositing on the sidewall of chamber

201

. Moreover, since precursor

230

discharged downward comprises monomeric CuCl, it can readily be reduced by atomic hydrogen. Thus, chlorine is removed therefrom by reduction in a short period of time. Consequently, the resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

in a short period of time.

Accordingly, since the sidewall of chamber

201

is heated to a predetermined temperature by heater

228

, precursor (CuCl)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Thus, precursor (CuCl)

230

is prevented from depositing on the sidewall of chamber

201

. Consequently, the necessity of cleaning the inside of chamber

201

periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost. Moreover, since discharge plate

209

is uniformly heated to a desired temperature by the collision of He ions, a monomeric precursor (CuCl)

230

which can readily be reduced is produced. This makes it possible to remove chlorine by reduction in a short period of time and thereby improve the rate of film growth.

Now, an apparatus and method for the formation of a metal film in accordance with a ninth embodiment of the present invention is described with reference to FIG.

13

.

FIG. 13

is a schematic side view of the apparatus for the formation of a metal film in accordance with the ninth embodiment of the present invention. The same components as those shown in

FIG. 10

are designated by the same reference numerals and the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film as illustrated in

FIG. 10

, the apparatus for the formation of a metal film in accordance with the ninth embodiment as illustrated in

FIG. 13

is characterized in that an atomic reducing gas

251

id produced in place of the reducing gas plasma comprising H

2

gas plasma

232

. To this end, this apparatus includes a reducing gas heating means

252

for heating a reducing gas (e.g., H

2

gas)

213

to produce an atomic reducing gas

251

, in place of second plasma generating means

203

. This reducing gas heating means

252

consists of a reducing gas flow controller

214

, a reducing gas nozzle

215

attached thereto, and tungsten filament

253

disposed within reducing gas nozzle

215

. The ends of tungsten filament

215

are connected to a direct-current power supply

254

.

In the above-described apparatus for the formation of a metal film, Cl

2

gas is fed into inlet vessel

206

. When electromagnetic waves are radiated into inlet vessel

206

by first plasma antenna

222

of first plasma generating means

202

, the Cl

2

gas within inlet vessel

206

is ionized to generate Cl

2

gas plasma (raw material gas plasma)

231

. This Cl

2

gas plasma

231

causes an etching reaction of discharge plate

209

made of Cu, so that a precursor (Cu

x

Cl

y

)

230

is produced. This precursor (Cu

x

Cl

y

)

230

is discharged downward through discharge orifices

210

.

Immediately before precursor (Cu

x

Cl

y

)

230

arrives at substrate

212

, a reducing gas

213

comprising H

2

gas is passed through reducing gas flow controllers

214

in order to control its flow rate, and tungsten filament

253

is heated to 1,800° C. by means of direct-current power supply

254

. As a result of the hearing of tungsten filament

253

, an atomic reducing gas

251

(atomic hydrogen) is produced and injected into chamber

201

through reducing gas inlet nozzle

215

. Consequently, precursor (Cu

x

Cl

y

)

230

discharged downward through discharge orifices

210

passes through atomic reducing gas

251

immediately before arriving at substrate

212

. Thus, chlorine is removed from precursor (Cu

x

Cl

y

)

230

by a reduction reaction with atomic hydrogen. The resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

.

Since the sidewall of chamber

201

is heated to a predetermined temperature (e.g., 200° C.) by heater

228

, precursor (Cu

x

Cl

y

)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Consequently, precursor (Cu

x

Cl

y

)

230

is prevented from depositing on the sidewall of chamber

201

.

In the above-described apparatus for the formation of a metal film, since chlorine gas (Cl

2

gas) is used as raw material gas

205

and a hydrogen-containing gas is used as reducing gas

213

, a marked reduction in cost is achieved. Moreover, since the reduction reaction can be accelerated independently, the amount of impurities (e.g., chlorine) remaining in thin Cu film

233

can be minimized to form a thin Cu film

233

of high quality. Furthermore, since atomic reducing gas

251

comprising atomic hydrogen can be fed simply by use of reducing gas nozzle

215

which permits a relatively flexible arrangement, a film having a large area (e.g., 50 mm×50 mm) can be stably formed.

In addition, since the sidewall of chamber

201

is heated to a predetermined temperature by heater

228

, precursor (Cu

x

Cl

y

)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Thus, precursor (Cu

x

Cl

y

)

230

is prevented from depositing on the sidewall of chamber

201

. Consequently, the necessity of cleaning the inside of chamber

201

periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost.

Now, an apparatus and method for the formation of a metal film in accordance with a tenth embodiment of the present invention is described with reference to FIG.

14

.

FIG. 14

is a schematic side view of the apparatus for the formation of a metal film in accordance with the tenth embodiment of the present invention. The same components as those shown in

FIG. 13

are designated by the same reference numerals and the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film as illustrated in

FIG. 13

, the apparatus for the formation of a metal film in accordance with the tenth embodiment as illustrated in

FIG. 14

does not include the chamber heating means comprising filament type heater

228

and power supply

229

, but includes a discharge plate heating means for heating discharge plate

209

. Specifically, discharge plate (or metallic plate)

209

made of Copper (Cu) is provided at the bottom of inlet vessel

206

through the medium of an insulating member

241

. An auxiliary nozzle

242

for feeding a rare gas comprising He gas is connected to the sidewall of inlet vessel

206

. Thus, He gas is fed into inlet vessel

206

together with raw material gas

205

comprising chlorine gas (Cl

2

gas). Cl

2

gas and He gas are fed into inlet vessel

206

in a ratio of approximately 1:1. A biasing power supply

243

is connected to discharge plate

209

, so that a direct-current voltage is applied to discharge plate

209

by biasing power supply

243

.

In the above-described apparatus for the formation of a metal film, when electromagnetic waves are radiated into inlet vessel

206

by first plasma antenna

222

of first plasma generating means

202

, the Cl

2

gas and He gas within inlet vessel

206

are ionized to generate Cl

2

—He gas plasma

244

. This Cl

2

—He gas plasma

244

causes He ions to collide with discharge plate

209

to which a bias voltage is applied. Thus, discharge plate

209

is uniformly heated. As the means for heating discharge plate

209

, a heater or other means for heating discharge plate

209

directly may also be used in place of the means based on the collision of He ions.

The heating temperature of discharge plate

209

is, for example, in the range of 200 to 800° C. and preferably 600° C. It is preferable that the lower limit of the heating temperature is a temperature at which precursor (Cu

x

Cl

y

)

230

passing through discharge orifices

210

becomes a monomeric compound rather than a polymeric one. When discharge plate

209

is heated to 600° C., precursor

230

tends to be monomeric CuCl and this facilitates the reduction reaction which will be described later. The upper limit of the heating temperature depends on the material of discharge plate

209

. In the case of discharge plate

209

made of copper (Cu), the upper limit is 800° C. If the heating temperature exceeds 800° C., discharge plate

209

cannot be used because of its softening. Discharge plate

209

can be adjusted to a desired temperature by controlling the voltage applied to discharge plate

209

.

When Cl

2

—He gas plasma

244

is generated within inlet vessel

206

, the Cl

2

gas plasma causes an etching reaction of the heated discharge plate

209

made of Cu, so that a monomeric precursor (CuCl)

230

tends to be produced. The resulting precursor (CuCl)

230

is discharged downward through discharge orifices

210

of discharge plate

209

. Immediately before precursor (CuCl)

230

discharged downward through discharge orifices

210

arrives at substrate

212

, it passes through atomic reducing gas

251

. Thus, chlorine is removed from precursor (CuCl)

230

by a reduction reaction with atomic hydrogen. The resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

.

Since precursor

230

discharged downward comprises monomeric CuCl, it can readily be reduced by atomic hydrogen. Thus, chlorine is removed therefrom by reduction in a short period of time. Consequently, the resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

in a short period of time. That is, since discharge plate

209

is uniformly heated to a desired temperature by the collision of He ions, a monomeric precursor (CuCl)

230

which can readily be reduced is produced. This makes it possible to remove chlorine by reduction in a short period of time and thereby improve the rate of film growth.

Now, an apparatus and method for the formation of a metal film in accordance with an eleventh embodiment of the present invention is described with reference to FIG.

15

.

FIG. 15

is a schematic side view of the apparatus for the formation of a metal film in accordance with the eleventh embodiment of the present invention. The same components as those shown in

FIGS. 13 and 14

are designated by the same reference numerals and the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film as illustrated in

FIG. 14

, the apparatus for the formation of a metal film in accordance with the eleventh embodiment as illustrated in

FIG. 15

includes a chamber heating means comprising a filament type heater

228

and a power supply

229

. That is, this apparatus is equipped with both the chamber heating means and the discharge plate heating means.

Thus, since the sidewall of chamber

201

is heated to a predetermined temperature (e.g., 200° C.) by heater

228

, precursor (CuCl)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Consequently, precursor (CuCl)

230

is prevented from depositing on the sidewall of chamber

201

. Moreover, since precursor

230

discharged downward comprises monomeric CuCl, it can readily be reduced by atomic hydrogen. Thus, chlorine is removed therefrom by reduction in a short period of time. Consequently, the resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

in a short period of time.

Accordingly, since the sidewall of chamber

201

is heated to a predetermined temperature by heater

228

, precursor (CuCl)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Thus, precursor (CuCl)

230

is prevented from depositing on the sidewall of chamber

201

. Consequently, the necessity of cleaning the inside of chamber

201

periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost. Moreover, since discharge plate

209

is uniformly heated to a desired temperature by the collision of He ions, a monomeric precursor (CuCl)

230

which can readily be reduced is produced. This makes it possible to remove chlorine by reduction in a short period of time and thereby improve the rate of film growth.

Now, an apparatus and method for the formation of a metal film in accordance with a twelfth embodiment of the present invention is described with reference to FIG.

16

.

FIG. 16

is a schematic side view of the apparatus for the formation of a metal film in accordance with the twelfth embodiment of the present invention. The same components as those shown in

FIG. 13

are designated by the same reference numerals and the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film as illustrated in

FIG. 13

, the apparatus for the formation of a metal film in accordance with the twelfth embodiment as illustrated in

FIG. 16

is characterized in that a precursor (Cu

x

Cl

y

)

230

is injected into chamber

201

from a nozzle

208

of a raw material gas heating means

261

, instead of generating Cl

2

gas plasma

231

within inlet vessel

206

to produce precursor (Cu

x

Cl

y

)

230

. Raw material gas heating means

261

consists of a flow controller

207

, a nozzle

208

attached thereto, and a copper filament

262

comprising several turns of copper wire and disposed within nozzle

208

. The ends of copper filament

262

are connected to a direct-current power supply

263

. Copper filament

262

is heated to 300-600° C. by direct-current power supply

263

.

In the above-described apparatus for the formation of a metal film, a raw material gas comprising Cl

2

gas is passed through flow controller

207

in order to control its flow rate, and then fed into nozzle

208

. Since nozzle

208

is provided therein with copper filament

262

which has been heated to 300-600° C. by direct-current power supply

263

, the contact of Cl

2

gas with the heated copper filament

262

produces a precursor (Cu

x

Cl

y

)

230

. When this precursor (Cu

x

Cl

y

)

230

is introduced into chamber

201

through nozzle

208

, precursor (Cu

x

Cl

y

)

230

moves downward.

Immediately before precursor (Cu

x

Cl

y

)

230

arrives at substrate

212

, a reducing gas

213

comprising H

2

gas is passed through reducing gas flow controllers

214

in order to control its flow rate, and tungsten filament

253

is heated to 1,800° C. by means of direct-current power supply

254

. As a result of the hearing of tungsten filament

253

, an atomic reducing gas

251

(atomic hydrogen) is produced and injected into chamber

201

through reducing gas inlet nozzle

215

. Consequently, precursor (Cu

x

l

y

)

230

discharged downward through discharge orifices

210

passes through atomic reducing gas

251

immediately before arriving at substrate

212

. Thus, chlorine is removed from precursor (Cu

x

Cl

y

)

230

by a reduction reaction with atomic hydrogen. The resulting Cu ions are directed onto substrate

212

to form a thin Cu film

233

on the surface of substrate

212

.

Since the sidewall of chamber

201

is heated to a predetermined temperature (e.g., 200° C.) by heater

228

as described previously, precursor (Cu

x

Cl

y

)

230

adhering to-the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Consequently, precursor (Cu

x

Cl

y

)

230

is prevented from depositing on the sidewall of chamber

201

.

In the above-described apparatus for the formation of a metal film, since precursor (Cu

x

Cl

y

)

230

can be fed simply by use of nozzle

208

which permits a relatively flexible arrangement, and atomic hydrogen can be fed simply by use of reducing gas nozzle

215

which permits a relatively flexible arrangement, a film having a large area (e.g., 100 mm×100 mm) can be very stably formed.

Moreover, since the sidewall of chamber

201

is heated to a predetermined temperature by heater

228

, precursor (CuCl)

230

adhering to the sidewall of chamber

201

will readily be vaporized because of its raised vapor pressure. Thus, precursor (CuCl)

230

is prevented from depositing on the sidewall of chamber

201

. Consequently, the necessity of cleaning the inside of chamber

201

periodically can be eliminated to cause an improvement in raw material efficiency and a reduction in running cost.

FIG. 17

is a schematic sectional view of an apparatus for the vapor phase growth of a thin copper film in accordance with a thirteenth embodiment of the present invention, and

FIG. 18

is a plan view of a discharge plate made of copper and incorporated into the vapor phase growth apparatus of FIG.

17

.

Within a reaction vessel

302

formed into the shape of a box and provided with an exhaust tube

301

at the bottom, a flat plate type heater

303

is disposed and a substrate to be treated is placed thereon. An evacuation means (not shown), such as a vacuum pump, is connected to the other end of the aforesaid exhaust tube

301

. An inlet vessel

306

in the form of a closed-end cylinder, which has a copper discharge plate

305

having a plurality of discharge orifices

304

bored therethrough at the bottom, is suspended in the upper part of the aforesaid reaction vessel

302

. The aforesaid copper discharge plate

305

is provided with a circulation pipe

307

serving as a temperature control means for passing a heating medium (e.g., heated air) or a cooling medium (e.g., cooled air) therethrough. As illustrated in

FIG. 18

, this circulation pipe

307

is built in the aforesaid copper discharge plate

305

so that it lies in parallel with the surfaces of discharge plate

305

and runs in a serpentine manner.

A raw material gas feed pipe

308

for feeding chlorine or hydrogen chloride extends from the outside through the sidewall of the aforesaid reaction vessel

302

and the sidewall of the aforesaid inlet vessel

306

, and is inserted into the interior of the aforesaid inlet vessel

306

. A flow controller

309

is installed in a portion of the aforesaid raw material gas feed pipe

308

which is located on the outside of the aforesaid reaction vessel

302

. A first plasma generator

310

is disposed on the top surface of the aforesaid reaction vessel

302

to which the aforesaid inlet vessel

306

is attached. This first plasma generator

310

consists of an insulating plate

311

disposed on the top surface of the aforesaid reaction vessel

302

so as to cover the aforesaid inlet vessel

306

, a first plasma antenna

312

disposed on this insulating plate

311

, and a first plasma power supply

313

connected to this first plasma antenna

312

.

A water partial pressure gauge

315

having two sensing elements

314

a

and

314

b

is disposed on the outside of the aforesaid reaction vessel

302

. One sensing elements

314

a

extends through the sidewall of the aforesaid reaction vessel

302

and the sidewall of the aforesaid inlet vessel

306

, and is inserted into the interior of the aforesaid inlet vessel

306

. The other sensing elements

314

b

extends through the sidewall of the aforesaid reaction vessel

302

and is inserted into the interior of the aforesaid reaction vessel

302

. The aforesaid water partial pressure gauge

341

is used to measure the partial pressure of water when the aforesaid reaction vessel

302

and the aforesaid inlet vessel

306

are evacuated prior to film formation. A hydrogen feed pipe

316

for feeding a reducing gas (e.g., hydrogen) extends from the outside through the lower sidewall of the aforesaid reaction vessel

302

and is inserted into the interior of the aforesaid reaction vessel

302

. A flow controller

317

is installed in a portion of the aforesaid hydrogen feed pipe

316

which is located on the outside of the aforesaid reaction vessel

302

. A second plasma generator

318

is disposed at the bottom of the aforesaid reaction vessel

302

. This second plasma generator

318

consists of an insulating plate

319

disposed on the bottom surface of the aforesaid reaction vessel

302

, a second plasma antenna

320

disposed on the underside of this insulating plate

319

, and a second plasma power supply

321

connected to the underside of this second plasma antenna

320

. A rotating magnetic field coil

322

is disposed around the lower sidewall of the aforesaid reaction vessel

302

with a desired space left therebetween. This rotating magnetic field coil

322

acts on the hydrogen plasma generated above the aforesaid heater

303

of the aforesaid reaction vessel

302

as will be described later so that the hydrogen plasma may be densely distributed in the neighborhood of the surface of the substrate to be treated which is placed on the aforesaid heater

303

.

Now, the method for forming a thin copper film by using the above-described apparatus for the vapor phase growth of a thin copper film as illustrated in

FIGS. 17 and 18

is described below.

First of all, a substrate

323

to be treated is placed on the flat plate type heater

303

of reaction vessel

302

. An evacuation means (not shown) is operated to remove the gas (air) within the aforesaid reaction vessel

302

and inlet vessel

306

through exhaust tube

301

until a predetermined degree of vacuum is reached.

In this evacuation step, the partial pressures of water within the aforesaid reaction vessel

302

and inlet vessel

306

are measured by means of water partial pressure gauge

315

to confirm that the partial pressures of water remain constant. After the partial pressures of water have been confirmed, hydrogen is fed into the aforesaid reaction vessel

302

through hydrogen feed pipe

316

. The flow rate of this hydrogen is controlled by means of flow controller

317

installed in the aforesaid hydrogen feed pipe

316

. The second plasma power supply

321

of second plasma generator

318

is operated to apply, for example, high-frequency electric power to the aforesaid second plasma antenna

320

and thereby generate hydrogen plasma

324

above and near the aforesaid substrate

323

to be treated. Under the action of a rotating magnetic field created by rotating magnetic field coil

322

disposed on the outside of the aforesaid reaction vessel

302

, the aforesaid hydrogen plasma

324

is densely distributed in the neighborhood of the surface of the aforesaid substrate

323

to be treated.

Then, a raw material gas comprising, for example, chlorine (Cl

2

) is fed into the aforesaid inlet vessel

306

through raw material gas feed pipe

308

. The flow rate of this chlorine is controlled by means of flow controller

309

installed in the aforesaid raw material gas feed pipe

308

. A heating medium (e.g., heated air) heated to a predetermined temperature is supplied to and circulated through the circulation pipe

307

of copper discharge plate

305

. Thus, copper discharge plate

305

is heated to a predetermined temperature. After heating copper discharge plate

305

, the first plasma power supply

313

of first plasma generator

310

is operated to apply, for example, high-frequency electric power to the aforesaid first plasma antenna

312

and thereby generate chlorine plasma

325

within the aforesaid inlet vessel

306

. If the temperature of the aforesaid discharge plate

305

is excessively raised with the generation of chlorine plasma

325

, the aforesaid discharge plate

305

may be adjusted to a desired temperature by supplying a cooling medium to the aforesaid circulation pipe

307

in place of the aforesaid heating medium.

As a result of the above-described generation of chlorine plasma

324

, activated chlorine in this plasma

324

reacts with copper discharge plate

305

which has been heated to a predetermined temperature by supplying and circulating a heating medium through the aforesaid circulation pipe

307

. Thus, a precursor (Cu

x

Cl

y

) comprising copper chloride is produced. As shown by arrows in

FIG. 17

, the resulting precursor (Cu

x

Cl

y

) is discharged into the aforesaid reaction vessel

302

through the plurality of discharge orifices

304

of the aforesaid discharge plate

305

. Immediately before the discharged precursor arrives at substrate

323

to be treated which is placed on flat plate type heater

303

, it passes through the aforesaid hydrogen plasma

324

and undergoes a reduction reaction with atomic hydrogen in this hydrogen plasma

324

. Consequently, copper produced by the reduction reaction of the precursor (Cu

x

Cl

y

) with atomic hydrogen grows on the aforesaid substrate

323

to be treated, resulting in the formation of a thin copper film.

Thus, according to the thirteenth embodiment, an inexpensive copper chloride precursor (Cu

x

Cl

y

) useful as a raw material for the vapor phase growth of copper can be produced by feeding inexpensive chlorine into inlet vessel

306

having copper discharge plate

305

at the bottom through raw material feed pipe

308

, generating chlorine plasma

325

within the aforesaid inlet vessel

306

by means of first plasma generator

310

, and reacting activated chlorine in this plasma

325

with the aforesaid copper discharge plate

305

. Moreover, since the reaction of activated chlorine in plasma

325

with the aforesaid copper discharge plate

305

can be accelerated by supplying and circulating a heating medium through circulation pipe

307

built in the aforesaid copper discharge plate

305

and thus heating the aforesaid copper discharge plate

305

to a predetermined temperature, the amount of precursor (Cu

x

Cl

y

) produced can be increased.

The precursor so produced is discharged into reaction vessel

302

through the plurality of discharge orifices

304

of the aforesaid discharge plate

305

, and subjected to a reduction reaction with atomic hydrogen while it passes through hydrogen plasma

324

previously generated within the aforesaid reaction vessel

302

.

Thus, a thin copper film can be rapidly formed on the aforesaid substrate

323

to be treated, because copper can grow at a relatively higher rate than in thermal decomposition processes.

Moreover, copper discharge plate

305

begins to react with activated chlorine in the aforesaid chlorine plasma

325

when copper discharge plate

305

is heated to a certain temperature by supplying and circulating a heating medium through circulation pipe

307

built in copper discharge plate

305

. Consequently, the pressure of the precursor discharged through the plurality of discharge orifices

304

of the aforesaid copper discharge plate (i.e., the discharge pressure) can be stabilized.

Moreover, the same type of precursor (Cu

x

Cl

y

) is produced. As a result, the rate of copper film growth on the aforesaid substrate

323

to be treated can be stabilized, so that a thin copper film having a desired thickness can be reproducibly formed on the aforesaid substrate

323

to be treated.

Furthermore, not only the aforesaid precursor (Cu

x

Cl

y

) undergoes a reduction reaction with atomic hydrogen while it passes through hydrogen plasma

324

, and causes the vapor phase growth of copper on the surface of the aforesaid substrate

323

to be treated, but also atomic hydrogen in hydrogen plasma

324

exerts a reducing action on the growing copper film. Consequently, a thin copper film containing little residual can be formed.

In the above-described thirteenth embodiment, a circulation pipe for passing a heating medium or cooling medium therethrough is used as the temperature control means for the aforesaid copper discharge plate. However, the present invention is not limited thereto, but the aforesaid copper discharge plate may be provided with a combination of a heater and a circulation pipe for a cooling medium.

Although chlorine is used as the raw material gas in the above-described thirteenth embodiment, a copper chloride precursor (Cu

x

Cl

y

) can also be produced by using hydrogen chloride.

Although atomic hydrogen is produced by converting hydrogen into a plasma in the above-described thirteenth embodiment, atomic hydrogen may also be produced by installing a heater (e.g., a tungsten filament) for heating hydrogen fed into the aforesaid reaction vessel.

FIG. 19

is a schematic sectional view of an apparatus for the vapor phase growth of a thin copper film in accordance with a fourteenth embodiment of the present invention, FIG.

20

(A) is a longitudinal sectional view of a spiral tube incorporated into the vapor phase growth apparatus of

FIG. 19

, FIG.

20

(B) is a transverse sectional view of this spiral tube, FIG.

21

(A) is a longitudinal sectional view of another type of spiral tube incorporated into the vapor phase growth apparatus of

FIG. 19

, and FIG.

21

(B) is a transverse sectional view of this spiral tube.

Within a reaction vessel

332

formed into the shape of a box and provided with an exhaust tube

331

at the bottom, a flat plate type heater

333

is disposed and a substrate to be treated is placed thereon. An evacuation means (not shown), such as a vacuum pump, is connected to the other end of the aforesaid exhaust tube

331

.

A raw material gas feed pipe

334

for feeding chlorine or hydrogen chloride extends from the outside through the sidewall of the aforesaid reaction vessel

332

and is inserted into the upper part of the aforesaid reaction vessel

332

. A flow controller

335

is installed in a portion of the aforesaid raw material gas feed pipe

334

which is located on the outside of the aforesaid reaction vessel

332

. The aforesaid reaction vessel

332

includes a spiral tube

336

having a raw material gas flow passage whose inner surface is made of copper, and equipped with a heating element. Its upper end is connected to the end of the aforesaid raw material gas feed pipe

334

which is located on the inside of the aforesaid reaction vessel

332

. This spiral tube

336

has, for example, a dual tubular structure consisting of an outer tube

337

and an inner copper tube

338

inserted into this outer tube

337

and connected to the aforesaid raw material gas feed pipe

334

, as illustrated in FIG.

20

. The aforesaid raw material gas is made to flow through the aforesaid inner copper tube

338

, and a heating medium (e.g., heated air) is made to flow through the annular space between the aforesaid outer tube

337

and the aforesaid inner copper tube

338

. A heating medium feed pipe (not shown), which extends through a wall of the aforesaid reaction vessel

332

, is connected to a portion of outer tube

337

of spiral tube

336

which is located in the neighborhood of its joint with the aforesaid raw material gas feed pipe

334

, and used to feed a heating medium into the annular space between the aforesaid outer tube

337

and the aforesaid inner copper tube

338

. Moreover, a heating medium discharge pipe (not shown), which extends through a wall of the aforesaid reaction vessel

332

, is connected to a portion of outer tube

337

which is located in the neighborhood of the lower end of the aforesaid spiral tube

336

, and used to discharge the heating medium fed into the aforesaid annular space to the outside.

A precursor discharge member

339

is disposed within the aforesaid reaction vessel

332

in such a way that the aforesaid precursor discharge member

339

lies under the aforesaid spiral tube

336

and its upper part is connected to the aforesaid spiral tube

336

.

A water partial pressure gauge

341

having two sensing elements

340

a

and

340

b

is disposed on the outside of the aforesaid reaction vessel

332

. One sensing elements

340

a

extends through the sidewall of the aforesaid reaction vessel

332

and the outer tube

337

and inner copper tube

338

of the aforesaid spiral tube

336

, and is inserted into the interior of the aforesaid inner copper tube

338

. The other sensing elements

340

b

extends through the sidewall of the aforesaid reaction vessel

332

and is inserted into the interior of the aforesaid reaction vessel

332

. The aforesaid water partial pressure gauge

341

is used to measure the partial pressure of water when the aforesaid reaction vessel

332

and the inner copper tube

338

of the aforesaid spiral tube

336

are evacuated prior to film formation.

A hydrogen feed pipe

342

for feeding a reducing gas (e.g., hydrogen) extends from the outside through the lower sidewall of the aforesaid reaction vessel

332

and is inserted into the interior of the aforesaid reaction vessel

332

. A flow controller

343

is installed in a portion of the aforesaid hydrogen feed pipe

342

which is located on the outside of the aforesaid reaction vessel

332

. A plasma generator

344

is disposed at the bottom of the aforesaid reaction vessel

332

. This plasma generator

344

consists of an insulating plate

345

disposed on the bottom surface of the aforesaid reaction vessel

332

, a plasma antenna

346

disposed on the underside of this insulating plate

345

, and a plasma power supply

347

connected to the underside of this plasma antenna

346

. A rotating magnetic field coil

348

is disposed around the lower sidewall of the aforesaid reaction vessel

332

with a desired space left therebetween. This rotating magnetic field coil

348

acts on the hydrogen plasma generated above the aforesaid heater

333

of the aforesaid reaction vessel

332

as will be described later so that the hydrogen plasma may be densely distributed in the neighborhood of the surface of the substrate to be treated which is placed on the aforesaid heater

333

.

Now, the method for forming a thin copper film by using the above-described apparatus for the vapor phase growth of a thin copper film as illustrated in

FIGS. 19 and 20

is described below.

First of all, a substrate

349

to be treated is placed on the flat plate type heater

333

of reaction vessel

332

. An evacuation means (not shown) is operated to remove the gas (air) within the aforesaid reaction vessel

332

and the inner copper tube

338

of spiral tube

336

through exhaust tube

331

until a predetermined degree of vacuum is reached.

In this evacuation step, the partial pressures of water within the aforesaid reaction vessel

332

and the inner copper tube

338

of spiral tube

336

are measured by means of water partial pressure gauge

341

to confirm that the partial pressures of water remain constant. After the partial pressures of water have been confirmed, hydrogen is fed into the aforesaid reaction vessel

332

through hydrogen feed pipe

342

. The flow rate of this hydrogen is controlled by means of flow controller

343

installed in the aforesaid hydrogen feed pipe

342

. The plasma power supply

347

of plasma generator

344

is operated to apply, for example, high-frequency electric power to the aforesaid plasma antenna

346

and thereby generate hydrogen plasma

350

above and near the aforesaid substrate

349

to be treated. Under the action of a rotating magnetic field created by rotating magnetic field coil

348

disposed on the outside of the aforesaid reaction vessel

332

, the aforesaid hydrogen plasma

350

is densely distributed in the neighborhood of the surface of the aforesaid substrate

349

to be treated.

Then, a raw material gas comprising, for example, chlorine (Cl

2

) is fed into the inner copper tube

338

of the aforesaid spiral tube

336

through raw material gas feed pipe

334

. The flow rate of this chlorine is controlled by means of flow controller

335

installed in the aforesaid raw material gas feed pipe

334

. A heating medium (e.g., heated air) heated to a predetermined temperature is supplied from the outside of the aforesaid reaction vessel

332

through a heating medium feed pipe (not shown) to the annular space between the outer tube

337

and inner copper tube

338

of the aforesaid spiral tube

336

. This heating medium is discharged to the outside through a heating medium discharge pipe (not shown). Thus, the inner copper tube

338

of the aforesaid spiral tube

336

is heated to a predetermined temperature, so that the aforesaid inner copper tube

338

reacts with the chlorine (Cl

2

) flowing therethrough to produce a precursor (Cu

x

Cl

y

) comprising copper chloride.

As shown by arrows in

FIG. 19

, the resulting precursor (Cu

x

Cl

y

) is discharged into the aforesaid reaction vessel

332

from precursor discharge member

339

. Immediately before the discharged precursor arrives at substrate

349

to be treated which is placed on flat plate type heater

333

, it passes through the aforesaid hydrogen plasma

350

and undergoes a reduction reaction with atomic hydrogen in this hydrogen plasma

350

. Consequently, copper produced by the reduction reaction of the precursor (Cu

x

Cl

y

) with atomic hydrogen grows on the aforesaid substrate

349

to be treated, resulting in the formation of a thin copper film.

Thus, according to the fourteenth embodiment, an inexpensive copper chloride precursor (Cu

x

Cl

y

) useful as a raw material for the vapor phase growth of copper can be produced by feeding inexpensive chlorine into the inner copper tube

338

of spiral tube

336

, passing a heating medium through the annular space between the outer tube

337

and inner copper tube

338

of the aforesaid spiral tube

336

to heat the aforesaid inner copper tube

338

, and thus reacting chlorine with the aforesaid inner copper tube

338

.

The precursor so produced is discharged into reaction vessel

332

from precursor discharge member

339

, and subjected to a reduction reaction with atomic hydrogen while it passes through hydrogen plasma

350

previously generated within the aforesaid reaction vessel

332

. Thus, a thin copper film can be rapidly formed on the aforesaid substrate

349

to be treated, because copper can grow at a relatively higher rate than in thermal decomposition processes.

Moreover, the aforesaid inner copper tube

338

begins to react with chlorine flowing through this inner copper tube

338

when inner copper tube

338

is heated to a certain temperature by passing a heating medium through the annular space between the outer tube

337

and inner copper tube

338

of the aforesaid spiral tube

336

. Consequently, the pressure of the precursor discharged from the aforesaid precursor discharge member

339

(i.e., the discharge pressure) can be stabilized. Moreover, the same type of precursor (Cu

x

Cl

y

) is produced. As a result, the rate of copper film growth on the aforesaid substrate

349

to be treated can be stabilized, so that a thin copper film having a desired thickness can be reproducibly formed on the aforesaid substrate

349

.

Furthermore, not only the aforesaid precursor (Cu

x

Cl

y

) undergoes a reduction reaction with atomic hydrogen while it passes through hydrogen plasma

350

, and causes the vapor phase growth of copper on the surface of the aforesaid substrate

349

to be treated, but also atomic hydrogen in hydrogen plasma

350

exerts a reducing action on the growing copper film. Consequently, a thin copper film containing little residual impurity (e.g., chlorine) and hence having a good film quality can be formed.

In the above-described fourteenth embodiment, the spiral tube has a dual tubular structure and the aforesaid inner copper tube is heated by supplying a heating medium to the annular space between the outer tube and inner copper tube of the aforesaid spiral tube. However, the present invention is not limited to the above-described structure. For example, as illustrated in

FIG. 21

, spiral tube

336

may have a structure consisting of a copper tube

351

and a tubular heater

353

disposed around copper tube

351

with a tubular insulator

352

interposed therebetween. Thus, the aforesaid copper tube

351

can be heated to a predetermined temperature by the aforesaid tubular heater

353

.

Although chlorine is used as the raw material gas in the above-described fourteenth embodiment, a copper chloride precursor (Cu

x

Cl

y

) can also be produced by using hydrogen chloride.

Although atomic hydrogen is produced by converting hydrogen into a plasma in the above-described fourteenth embodiment, atomic hydrogen may also be produced by installing a heater or other means for heating hydrogen fed into the aforesaid reaction vessel.

Number	Date	Country
085511-2000	Mar 2000	JP
108120-2000	Apr 2000	JP
161507-2000	May 2000	JP
320136-2000	Oct 2000	JP

Number	Name	Date	Kind
4626448	Hays	Dec 1986	A
4829215	Kim et al.	May 1989	A
5091209	Claverie et al.	Feb 1992	A
5292370	Tsai et al.	Mar 1994	A
5716451	Hama et al.	Feb 1998	A
5980687	Koshimizu	Nov 1999	A
6174809	Kang et al.	Jan 2001	B1
6440494	Arena-Foster	Aug 2002	B1

Number	Date	Country
0 482 265	Apr 1992	EP
573348	Dec 1993	EP
61-86942	May 1986	JP
2856782	May 1991	JP
5-85890	Apr 1993	JP
05-198520	Aug 1993	JP
11-238698	Aug 1999	JP

Method for forming metallic film and apparatus for forming the same

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Term Extension

Abstract

Description

Claims

Priority Claims (4)

PCT Information

US Referenced Citations (8)

Foreign Referenced Citations (7)

Non-Patent Literature Citations (1)