Electrolytic processing apparatus and method

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to an electrolytic processing apparatus and method, and more particularly to an electrolytic processing apparatus and method useful for forming, by plating, a film of an interconnect material, such as copper, on a substrate having fine interconnect patterns (recesses) formed in a surface, or for removing, by electrolytic etching, a metal film formed in a surface of a substrate.

2. Description of the Related Art:

In recent years, instead of using aluminum or aluminum alloys as an interconnect material for forming electrical interconnects on a semiconductor substrate, there is an eminent movement toward using copper (Cu) which has a low electric resistivity and high electromigration endurance. It is generally difficult with copper to form interconnects by anisotropic etching as practiced with aluminum. Accordingly, copper interconnects are generally formed by the so-called copper damascene technique which comprises embedding of copper in fine recesses formed in a surface of a substrate. Known methods for forming such copper interconnects include CVD, sputtering and plating. According to any such method, a copper film is formed in almost the entire surface of a substrate, followed by removal of unnecessary copper by chemical mechanical polishing (CMP) or electrolytic etching.

FIG. 4 illustrates, in sequence of process steps, a process for producing a substrate W having such copper interconnects. First, as shown in FIG. 4A, an oxide film 2 of SiO₂is deposited on a conductive layer la in which semiconductor devices are formed and which is formed on a semiconductor base 1. Fine interconnect recesses, such as fine holes (via holes) 3 and interconnect trenches 4, are formed in the oxide film 2 by the lithography/etching technique. Thereafter, a barrier layer 5 of TaN or the like is formed on the entire surface, and a seed layer 7, serving as an electric feeding layer in electroplating, is formed on the barrier layer 5.

Then, as shown in FIG. 4B, copper plating of the surface of the substrate W is carried out to fill the fine holes 3 and the interconnect trenches 4 with copper and, at the same time, deposit a copper film 6 on the oxide film 2. Thereafter, the copper film 6 and the barrier layer 5 on the oxide film 2 are removed by chemical mechanical polishing (CMP) or electrolytic etching so as to make the surface of the copper film 6, filled in the fine holes 3 and the interconnect trenches 4, substantially flush with the surface of the oxide film 2. Interconnects formed of the copper film 6, as shown in FIG. 4C, are thus formed.

With the recent trend toward using copper as an interconnect material instead of aluminum, increasing attention has been directed to an electroplating apparatus for carrying out plating with a copper material, and to an electrolytic etching apparatus for carrying out electrolytic etching of a copper film.

FIG. 5 shows a conventional common electroplating apparatus for use in the production of copper interconnects. The electroplating apparatus includes a rectangular housing 12 and transport boxes 10 such as SMIF boxes, detachably mounted to the housing 12, each housing a number of substrates, such as semiconductor wafers. In the housing 12, there are housed a stage 14, four electroplating units 16 and two post-cleaning units 18. The apparatus is also provided in the housing 12 with a first transport robot 20 as a transport device for transporting a substrate between one of the transport boxes 10 and the stage 14, and a second transport robot 22 as a transport device for transporting the substrate between the stage 14, one of the electroplating units 16 and one of the post-cleaning units 18.

The apparatus also includes a plating solution supply facility 24 which is common to the four electroplating units 16. A common plating solution is supplied from the plating solution supply facility 24 to the respective electroplating units 16, and is returned to the plating solution supply facility 24.

In operation, one substrate is taken by the first transport robot 20 out of the transport boxes 10 housing substrates, and is placed on the stage 14. The substrate placed on the stage 14 is transported by the second transport robot 22 to one of the electroplating units 16, where electroplating, such as copper plating, of the substrate is carried out. The substrate after plating is transported by the second transport robot 22 to one of the post-cleaning units 18, where post-cleaning of the substrate and the subsequent spin-drying are carried out. The substrate after spin-drying is transported by the second transport robot 22 to the stage 14 and placed on the stage 14. The substrate placed on the stage 14 is then returned by the first transport robot 20 to the original position within the transport box 10.

The widths of current interconnects, such as copper interconnects, are generally within the range of 0.15 to 100 μm. A common plating solution for use in an electroplating apparatus contains copper sulfate, sulfuric acid, hydrochloric acid, a suppressor, an accelerator and a leveler. In general, one type of plating solution is used in one electroplating apparatus.

On the other hand, a two-step plating process has been proposed, which process comprises carrying out a first plating, either electroplating or electroless plating, of a substrate using a highly polar solution, such as a copper pyrophosphate plating solution, to reinforce or repair a seed layer 7 (see FIG. 4A), thereby completing the seed layer, and then carrying out a second plating using a copper sulfate plating solution to effect embedding of copper interconnects. It is also known to carry out multi-step plating by supplying several types of copper sulfate plating solutions having different embedding properties to one electroplating apparatus.

FIG. 6 shows a conventional electroplating apparatus for carrying out such multi-step plating. This apparatus is adapted to carry out two-step plating, and includes a first plating solution supply facility 24a for supplying a first plating solution, such as a copper pyrophosphate plating solution, and a second plating solution supply facility 24b for supplying a second plating solution, such as a copper sulfate plating solution. On the other hand, the four electroplating units 16 of the above-described apparatus are classified into two first electroplating units 16a, each connected to the first plating solution supply facility 24a, for carrying out plating using the first plating solution, and two second electroplating units 16b, each connected to the second plating solution supply facility 24b, for carrying out plating using the second plating solution. Further, a post-cleaning unit 18 and an intermediate cleaning unit 26 are provided as cleaning units.

In operation, a substrate is taken out of the transport box 10, transported to the stage 14 and placed on the stage 14 in the same manner as described above. The substrate placed on the stage 14 is transported to one of the first electroplating units 16a, where the first plating of the substrate is carried out using the first plating solution. Thereafter, the substrate is transported by the second transport robot 22 to the intermediate cleaning unit 26, where intermediate cleaning of the substrate is carried out. The substrate after intermediate cleaning is transported by the second transport robot 22 to one of the second electroplating units 16b, where the second plating of the substrate is carried out using the second plating solution. After carrying out post-cleaning and spin-drying of the substrate in the above-described manner, the substrate is returned to the transport box 10.

As in this apparatus, different electroplating units may be employed for different plating solutions, i.e., not using two or more plating solutions in one electroplating unit, so as to prevent a minute amount of an additive from being mixed into a plating solution and making the plating properties unstable.

In the field of LSI, for example, the development of a technology for forming ultrafine interconnects of not more than 0.15 μm is advancing. Plating solutions for use in the production of such interconnects are required to have embedding properties that meet the requirements of finer interconnects and a higher aspect ratio. The development of plating solutions is being confronted with such a difficult technical problem.

Ultrafine interconnects technology is a technology primarily for local interconnects, i.e. interconnects of the lower layers of a multi-layer interconnect structure, and probably may not be optimal, from a technical viewpoint and also in terms of cost, as a technology for forming global interconnects having an interconnect width of about 10 to 100 μm and a low aspect ratio. In this regard, it is noted that the plating properties required for global interconnects are so-called leveling properties, i.e. the properties that can provide a flat plated surface, whereas the plating properties required for local interconnects are embedding properties, more specifically properties of embedding an interconnect material, such as copper, in fine recesses having a high aspect ratio without the formation of voids. At present, a plating solution, which satisfies both of the different properties requirements, has not been developed yet.

For semiconductor devices which needs, for example, copper interconnects, small lot production of a variety of types is often required. The interconnect width, the number of layers of the multi-layer interconnect structure, etc. generally differ, between the various types of semiconductor devices to be processed. It is therefore difficult to form interconnects of all the layers and efficiently produce a variety of devices with the use of a single plating solution as in the conventional electroplating apparatus. Even when an apparatus construction that enables the use of two or more types of plating solutions, is adopted, if the operation is such that a specified electroplating unit is used solely for a particular plating solution, the apparatus can be operated only in an inflexible manner and at a high production cost.

While the electroplating apparatuses for carrying out copper plating have been described hereinabove, the situation is the same with electrolytic etching apparatus which carry out the reverse process to plating. Thus, although the properties of an electrolytic etching liquid can be adjusted by an additive or an electrolyte, similarly as in the case of a plating solution used in an electroplating apparatus, the process requirements differ between the upper layers and the lower layers of a multi-layer interconnect structure. Further, there are a variety of requirements for the uniformity of etched surface and the etching rate. Such requirements are furthermore diversified depending upon the interconnect width, the density of interconnects, the cross-sectional configuration, etc. There is, therefore, a need for the development of an apparatus which enables a flexible operation of different electrolytic etching liquids.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above situation in the related art. It is therefore an object of the present invention to provide an electrolytic processing apparatus and method which can produce products having various specifications with enhanced productivity, thus reducing the production cost, and which can respond flexibly to the movement toward finer interconnects in semiconductor devices.

In order to achieve the above object, the present invention provides an electrolytic processing apparatus comprising: an electrolytic processing unit including a substrate holder for holding a substrate, and a counter electrode plate disposed opposite the substrate held by the substrate holder, said electrolytic processing unit carrying out electrolytic processing by filling the space between the substrate held by the substrate holder and the counter electrode plate with an electrolysis solution while feeding electricity; and a plurality of electrolysis solution supply facilities for supplying different types of electrolysis solutions; wherein the electrolytic processing unit is selectively connectable to one of the plurality of electrolysis solution supply facilities.

By making the electrolytic processing unit selectively connectable to one of the plurality of electrolysis solution supply facilities for supplying different electrolysis solutions, the flexibility of the electrolytic processing apparatus can be enhanced. Since a plurality of chemical liquids (electrolysis solutions) having different chemical natures are supplied to a single electrolytic processing unit, it may be necessary to carry out operations, such as cleaning, blowing, cleaning with the same liquid, etc., upon a switch between liquids. Such operations, however, can be automated with ease. Depending upon the chemical liquid (electrolysis solution), these operations may not be necessary.

The electrolytic processing apparatus may further comprise an input device for inputting a signal for selection of one of the plurality of electrolysis solution supply facilities to be connected to the electrolytic processing unit.

According to this apparatus, information about the substrate, such as the type of the substrate, the layer to be processed, the elapsed processing time, etc. is inputted by the operator of the input device, for example on a screen. This makes it possible to make a switch to an appropriate electrolysis solution with proper timing based on the information. For example, it becomes possible to make a shift of electrolysis solution for every substrate or for every layer. It also becomes possible to carry out different electrolytic processing for one layer.

In a preferred embodiment of the present invention, the substrate is an interconnect substrate, and an electrolytic processing object on the substrate is copper or a metal containing copper.

The present invention may be applied primarily in the field of LSI, and provides an effective apparatus for carrying out electrolytic processing related to copper as the main material of fine interconnects. The processing material according to the present invention, however, is not limited to a copper material. The electrolytic processing includes plating, etching and elecrodeposition. Further, the present invention may also be effectively applied in other fields than LSI to carry out the processing based on the same processing principle.

The present invention also provides an electrolytic processing apparatus comprising; a transport device for transporting a substrate; a plurality of electrolytic processing units each including a substrate holder for holding a substrate, and a counter electrode plate disposed opposite the substrate held by the substrate holder, each of said electrolytic processing units carrying out electrolytic processing by filling the space between the substrate held by the substrate holder and the counter electrode plate with an electrolysis solution while feeding electricity; and a plurality of electrolysis solution supply facilities for supplying different types of electrolysis solutions; wherein each of the electrolytic processing units is selectively connectable to one of the plurality of electrolysis solution supply facilities.

The provision of a plurality of flexible electrolytic processing units in the electrolytic processing apparatus can broaden the range of application. The electrolytic processing facility is not necessarily a device. Thus, for example, the electrolysis solution may be supplied from an infrastructure of a production plant via a line.

When the number of substrates to be processed is small, the plurality of electrolytic processing units in one electrolytic processing apparatus may be operated so that substrates which satisfy a variety of requirements can be produced. When the number of substrates to be processed is large, a necessary number of substrate processing apparatuses may be operated. Further, the electrolytic processing units in each substrate processing apparatus may be finely classified, thereby enhancing the productivity.

The electrolytic processing apparatus may further comprise a cleaning unit for cleaning the substrate.

The electrolytic processing apparatus generally performs fine processing of the surface of a material on a substrate. It is therefore preferred that the cleaning unit for cleaning the substrate be a sophisticated one. The apparatus may also be provided with a heating device for annealing the substrate after electrolytic processing so as to stabilize the crystals of a metal film.

The electrolytic processing apparatus of the present invention may generally be used for processing of fine interconnects, such as ultrafine LSI interconnects, which are difficult to process with one processing liquid, and is particularly effective for substrates having interconnects with a width of less than 0.15 μm.

The present invention further provides an electrolytic processing method comprising: carrying out a first electrolytic processing by filling a space between a substrate and a counter electrode plate disposed opposite the substrate with a first electrolysis solution while feeding electricity; and carrying out a second electrolytic processing by filling the space between the substrate and the counter electrode plate with a second electrolysis solution which is different from the first electrolysis solution while feeding electricity.

The electrolytic processing method may further comprise cleaning the first electrolysis solution remaining on the substrate and drying the substrate after the first electrolytic processing.

In a preferred embodiment of the present invention, the first electrolysis solution is a copper pyrophosphate plating solution and the second electrolysis solution is a copper sulfate plating solution.

The above and other objects, features, and advantages of the present invention will be apparent from the following description when taken in conjunction with the accompanying drawings which illustrates preferred embodiments of the present invention by way of example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an electrolytic processing apparatus, which is employed as an electroplating apparatus, according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of an electrolytic processing apparatus, which is employed as an electroplating apparatus, according to another embodiment of the present invention;

FIG. 3 is an overall plan view of an electrolytic processing apparatus, which is employed as an electroplating apparatus provided with a plurality of electroplating units (electrolytic processing units), according to yet another embodiment of the present invention;

FIGS. 4A through 4C are diagrams illustrating, in sequence of process steps, a process of producing a substrate having copper interconnects;

FIG. 5 is an overall plan view of a conventional electroplating apparatus; and

FIG. 6 is an overall plan view of another conventional electroplating apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described with reference to the drawings. Though the following embodiments relate to application of the present invention to electroplating apparatuses, such apparatuses may of course be used as electrolytic etching apparatuses by applying a voltage, which allows an electric current to flow in a direction opposite to the direction of electric current in plating, between a substrate and a counter electrode plate while supplying an electrolysis solution (etching liquid) therebetween.

FIG. 1 is a schematic cross-sectional view of an electroplating apparatus (electrolytic processing apparatus) according to an embodiment of the present invention. As shown in FIG. 1, this electroplating apparatus includes an electroplating unit 30, two plating solution supply facilities (electrolysis solution supply facilities) 32a, 32b for supplying plating solutions as electrolysis solutions to the electroplating unit 30 and recovering the plating solutions, a control section 34, and an input device 36, for example comprised of a keyboard, for inputting a signal into the control section 34.

The electroplating unit 30, according to this embodiment, includes a substrate holder 40 which is rotatable and vertically movable, and detachably holds a substrate W with its front surface facing downwardly (face down), and a plating tank 42, disposed below the substrate holder 40, for holding a plating solution (electrolysis solution). In the plating tank 42 is formed a counter electrode plate chamber 48 defined by a side surrounding partition 44 and a top diaphragm 46. In the counter electrode plate chamber 48, a counter electrode plate 50, serving as a counter electrode (anode in the case of plating) to the substrate W, is disposed opposite the substrate W. The apparatus is also provided with a power source 51 for applying a plating voltage between the counter electrode plate 50 as an anode and a conductive material as a cathode, such as a seed layer 7 (see FIG. 4A), formed in the surface of the substrate W held by the substrate holder 40, and flowing a plating current therebetween.

In the case of an electrolytic etching apparatus, as described above, a etching (plating) voltage is applied between the counter electrode plate 50, serving in this case as a cathode, and a conductive material such as a seed layer (see FIG. 4A), serving as an anode, formed in the surface of a substrate W held by the substrate holder 40, thereby flowing a etching (plating) current therebetween.

One plating solution supply facility 32a is provided for holding and supplying a first plating solution, such as a copper pyrophosphate plating solution. A plating solution supply line 52a and a plating solution discharge line 54a extend from the plating solution supply facility 32a and are connected to the plating tank 42 of the electroplating unit 30. Shut-off valves 56a, 58a are interposed respectively in the plating solution supply line 52a and in the plating solution discharge line 54a.

The other plating solution supply facility 32b is provided for holding and supplying a second plating solution, such as a copper sulfate plating solution. A plating solution supply line 52b and a plating solution discharge line 54b extend from the plating solution supply facility 32b and are connected to the plating tank 42 of the electroplating unit 30. Shut-off valves 56b, 58b are interposed respectively in the plating solution supply line 52b and in the plating solution discharge line 54b.

The plating solution supply lines 52a, 52b are connected to the bottom of the plating tank 42 at positions between the sidewall of the plating tank 42 and the partition 44, and the plating solution discharge lines 54a, 54b are connected to upper portions of the plating tank 42. The first or second plating solution supplied into the plating tank 42 flows along the region between the sidewall of the plating tank 42 and the partition 44 and fills the plating tank 42, and is discharged from the upper portion of the plating tank 42 and returned to the plating solution supply facility 32a or 32b. Each plating solution circulates in this manner. The provision of the diaphragm 46 between the substrate W and the counter electrode plate 50 prevents the plating solution supplied into the plating tank 42 from hitting directly against the surface of the counter electrode plate 50, thereby preventing a black film or the like, formed on the surface of the counter electrode plate 50, from being curled up by the plating solution and flowing out. The diaphragm 46 is made of a water-permeable material, for example, a woven or non-woven fabric. It is also possible to use, instead of the diaphragm 46, a plate having a large number of pores therein.

The opening/closing of the shut-off valves 56a, 58a, 56b and 58b is controlled by an output signal from the control section 34. Information about the substrate, such as the type, the layer to be processed, the elapsed processing time, etc., is inputted by the input device 36, or automatically into the control section 34.

The operation of the electroplating apparatus will now be described taking as an example the case of embedding copper in fine holes 3 and interconnect trenches 4 formed in the surface of a substrate W, as shown in FIGS. 4A and 4B.

The substrate W has a layer structure as shown in FIG. 4A, and has been prepared by forming fine interconnect recesses, such as fine holes 3 and interconnect trenches 4, in a oxide film 2 on a conductive layer la, forming a barrier layer 5 of TaN or the like on the entire surface, and forming a seed layer 7, serving as an electric feeding layer upon electroplating, on the barrier layer 5. First, the substrate W is held with its surface facing downwardly by the substrate holder 40, and the substrate W held by the substrate holder 40 is lowered to a predetermined position at which the substrate W closes the top opening of the plating tank 42 and stopped.

The shut-off valves 56a, 58a, interposed in the plating solution supply line 52a and the plating solution discharge line 54a both extending from the plating solution supply facility 32a for holding and supplying the first plating solution, such as a copper pyrophosphate plating solution, are opened to supply the first plating solution into the plating tank 42 and circulate the first plating solution, thereby immersing the counter electrode plate 50 in the first plating solution and bringing the surface of the substrate W held by the substrate holder 40 into contact with the first plating solution. A plating voltage is applied between the counter electrode plate 50 as an anode and the seed layer 7 as a cathode formed in the surface of the substrate W held by the substrate holder 40, thereby flowing a plating current therebetween and carrying out electroplating of the surface of the substrate W. During the electroplating, the substrate W is rotated, according to necessity. The electroplating is carried out for a predetermined length of time to reinforce or repair the seed layer 7, thus completing the seed layer 7.

The electroplating with the first plating solution is terminated by stopping the application of the plating voltage between the seed layer 7 and the counter electrode plate 50. Thereafter, the first plating solution in the plating tank 42 is withdrawn through the plating solution supply line 52a and the plating solution discharge line 54a. If necessary, the substrate W after the electroplating with the first plating solution and the interior of the plating tank 42 are cleaned with e.g. pure water, followed by drying.

Next, the shut-off valves 56a, 58a, interposed in the plating solution supply line 52a and the plating solution discharge line 54a both extending from the plating solution supply facility 32a for holding and supplying the first plating solution, are closed, while the shut-off valves 56b, 58b, interposed in the plating solution supply line 52b and the plating solution discharge line 54b both extending from the plating solution supply facility 32b for holding and supplying the second plating solution, such as a copper sulfate plating solution, are opened to supply the second plating solution into the plating tank 42 and circulate the second plating solution, thereby immersing the counter electrode plate 50 in the second plating solution and bringing the surface of the substrate W held by the substrate holder 40 into contact with the second plating solution. A plating voltage is applied between the counter electrode plate 50 as an anode and the seed layer 7 as a cathode formed in the surface of the substrate W held by the substrate holder 40, thereby flowing a plating current therebetween and carrying out electroplating of the surface of the substrate W. During the electroplating, the substrate W is rotated, according to necessity. The electroplating is carried out for a predetermined length of time to embed copper in the fine interconnect recesses, such as fine holes 3 and interconnect trenches 4, and deposit a copper film 6 on the oxide film 2, as shown in FIG. 4B.

The electroplating with the second plating solution is terminated by stopping the application of the plating voltage between the seed layer 7 and the counter electrode plate 50. Thereafter, the second plating solution in the plating tank 42 is withdrawn through the plating solution supply line 52b and the plating solution discharge line 54b. If necessary, the substrate W after the electroplating with the second plating solution and the interior of the plating tank 42 are cleaned with e.g. pure water, followed by drying, thereby completing plating processing.

FIG. 2 is a schematic cross-sectional view of an electroplating apparatus (electrolytic processing apparatus) according to another embodiment of the present invention. This apparatus differs from the apparatus shown in FIG. 1 in the following respects.

The electroplating apparatus of this embodiment employs an electroplating unit 60 including a substrate holder 62 which is rotatable and vertically movable, and detachably holds a substrate W with its front surface facing upwardly (face up), a sealing member 64 disposed above the substrate holder 62 such that it covers the peripheral portion of the substrate W held by the substrate holder 62, and an electrode head 66 which is rotatable and vertically movable, and disposed above the substrate holder 62. The electrode head 66 includes a downwardly-upon housing 74 in which a counter electrode plate 68 is disposed. The bottom opening of the housing 74 is closed with a diaphragm 70, so that a plating solution chamber 72 is defined with the diaphragm 70 and the housing 74. The other construction of this apparatus is the same as the apparatus shown in FIG. 1.

According to this embodiment, the substrate W held with its surface facing upwardly by the substrate holder 62 is raised to bring a peripheral portion of the substrate W into pressure contact with the sealing member 64 to thereby water-tightly seal the peripheral portion, thereby forming a plating tank 76, defined by the substrate W and the sealing member 64, for holding a plating solution. The electrode head 66 is lowered until the distance between the upper surface (front surface) of the substrate W held by the substrate holder 62 and the lower surface of the diaphragm 70 reaches a predetermined valve. A plating solution is supplied into the plating tank 76, defined by the substrate W and the sealing member 64, so as to fill the plating solution chamber 72 with the plating solution, and the plating solution is circulated. A plating voltage is applied from the power source 51 to between the counter electrode plate 68 as an anode and e.g. a seed layer 7 (see FIG. 4A) as a cathode formed in the surface of the substrate W held by the substrate holder 62, thereby flowing a plating current therebetween and carrying out electroplating of the surface of the substrate W. During the electroplating, the substrate W and the diaphragm 70 are rotated, according to necessity. Further, a shift from electroplating with the first plating solution to electroplating with the second plating solution is made in the same manner as in the preceding embodiment.

FIG. 3 shows an overall plan view of an electroplating apparatus (electrolytic processing apparatus), which is provided with the electroplating unit (electrolytic processing unit) 30 (60) shown in FIG. 1 (or FIG. 2) but in plural numbers, according to yet another embodiment of the present invention.

The electroplating apparatus of this embodiment includes a rectangular housing 12 and transport boxes 10 such as SMIF boxes, detachably mounted to the housing 12, each housing a number of substrates, such as semiconductor wafers. In the housing 12, there are housed a stage 14, four electroplating units 30 (60) shown in FIG. 1 (or FIG. 2), for example, and two cleaning units 28 for carrying out at least one of intermediate cleaning and post-cleaning. The apparatus is also provided in the housing 12 with a first transport robot 20 as a transport device for transporting a substrate between one of the transport boxes 10 and the stage 14, and a second transport robot 22 as a transport device for transporting the substrate between the stage 14, one of the electroplating units 30 (60) and one of the cleaning units 28.

The apparatus also includes the above-described plating solution supply facility 32a for holding and supplying the first plating solution, such as a copper pyrophosphate plating solution, and the above-described plating solution supply facility 32b for holding and supplying the second plating solution, such as a copper sulfate plating solution. The plating solution supply line 52a and the plating solution discharge line 54a, both extending from the plating solution supply facility 32a, are each connected to the plating tank 42 (76) (see FIG. 1 and FIG. 2) of each electroplating unit 30 (60) and are each openable/closable to each plating tank 42 (76) by the shut-off valves 56a, 58a interposed in these lines. Likewise, the plating solution supply line 52b and the plating solution discharge line 54b, both extending from the plating solution supply facility 32b, are each connected to the plating tank 42 (76) of each electroplating unit 30 (60) and are each openable/closable to each plating tank 42 (76) by the shut-off valves 56b, 58b interposed in these lines.

As described above, the opening/closing of the shut-off valves 56a, 58a, 56b, 58b is controlled by an output signal from the control section 34. Information about the substrate, such as the type, the layer to be processed, the elapsed processing time, etc., is inputted by the input device 36, or automatically into the control section 34.

According to this embodiment, one substrate is taken by the first transport robot 20 out of the transport box 10 housing substrates, and is placed on the stage 14. The substrate placed on the stage 14 is transported by the second transport robot 22 to one of the electroplating units 30 (60), where electroplating of the substrate with the first plating solution is carried out in the above-described manner. The substrate after plating, if necessary, is transported to one of the cleaning units 28 to carry out intermediate cleaning of the substrate, and the substrate after cleaning is returned to the electroplating unit 30 (60). In the electroplating unit 30 (60), electroplating of the substrate with the second plating solution is carried out in the above-described manner. The substrate after plating is transported by the second transport robot 22 to the cleaning unit 28, where post-cleaning of the substrate and the subsequent spin-drying are carried out. The substrate after spin-drying is transported by the second transport robot 22 to the stage 14 and placed on the stage 14. The substrate placed on the stage 14 is then returned by the first transport robot 20 to the original position within the transport box 10.

Selection of an electrolysis solution can be made by using the input device 36 based on the specifications of the substrate to be processed, the number of substrates, the layer to be processed, etc. For example, information about the substrate, such as the type of the substrate, the layer to be processed, the elapsed processing time, etc. is inputted by the operator of the input device 36, for example on a screen. This makes it possible to make a switch to an appropriate electrolysis solution with proper timing based on the information. For example, it becomes possible make a shift of electrolysis solution for every substrate or for every layer. It also becomes possible to carry out different electrolytic processing for one layer.

According to this embodiment, the flexibility is given to the respective electroplating units 30 (60) independently, enabling a wide variety of processing manners. The cleaning unit 28 may be used not only for cleaning of a substrate after electrolytic processing, but also for cleaning in the course of processing. Regarding the transport boxes 10, it is possible, depending upon the degree of contamination of substrates to be processed, to separate boxes for carrying the substrates in the electrolytic processing apparatus and boxes for carrying the substrates out of the electrolytic processing apparatus.

The present invention makes it possible to efficiently use a plurality of electrolysis solutions. Any of a plating solution, an etching liquid and an electrodeposition liquid may be used as an electrolysis solution according to the present invention. Further, not only using a plurality of plating solutions for each substrate or each layer, but it is also possible to use, for example, a combination of a plating solution and an etching liquid for each substrate or each layer.

Further, by providing a counter electrode plate chamber separately from a plating tank, it becomes possible to separate an electrolysis solution for processing a substrate from a counter electrode liquid introduced into the counter electrode plate chamber, thereby broadening the application of electrolytic processing.

As described hereinabove, the present invention can provide an electrolytic processing apparatus and method which can produce products having various specifications with enhanced productivity, thus reducing the production cost, and which can respond flexibly to the movement toward finer interconnects in semiconductor devices.

Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.

Electrolytic processing apparatus and method

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