Patent Application
20150126027
The present disclosure relates to a method for manufacturing a semiconductor device.
Recently, it is required to produce a compact-sized electronic device having high speed and high reliability. To this end, a multilayer wiring structure in which a metal wiring is embedded in an interlayer insulating film by a damascene method is widely employed to obtain a miniaturized semiconductor device featuring high speed and high integration. Copper (Cu), which has low electromigration and low resistance, is generally used as a material for the metal wiring. The multilayer wiring structure is formed in the following sequence. First, a recess such as a trench is formed by removing an interlayer insulating film on a certain region until a wiring provided under the interlayer insulating film is exposed. Then, in order to suppress diffusion of the copper into the interlayer insulating film or the like, a barrier film is formed in the recess. Thereafter, a copper-containing film is buried to be formed on the barrier film in the recess.
Typically, tantalum (Ta), tantalum nitride (TaN) or the like is used as the barrier film. Recently, however, a technique using manganese oxide (MnOx) has been proposed to obtain a thin and highly uniform film. There has been proposed a method of forming an embedded electrode made of Cu on the MnOx film. Further, in order to increase the adhesion with Cu, there has been proposed a method of forming, on the MnOx film, a ruthenium (Ru) film having high adhesiveness to Cu and then forming an embedded electrode made of Cu on the Ru film.
However, when the MnOx film is formed by ALD (Atomic Layer Deposition), since a reaction between a Mn precursor and H2O causes the MnOx film to be formed, the MnOx film is formed not only on a side surface of the recess but also on a bottom surface of the recess where Cu is exposed. In addition, even when a Mn film is formed by thermal CVD (Chemical Vapor Deposition) or plasma enhanced CVD, if a native oxide film (CuOx) on the Cu surface is not completely removed but remains on the Cu surface, a reaction between the formed metal Mn and the CuOx causes a MnOx film to be also formed on the bottom surface of the recess where Cu is exposed. Since the MnOx film thus formed has high resistance compared with metal such as Cu, even if the embedded electrode made of Cu is formed on the MnOx film, sufficient conductivity cannot be obtained due to interposition of the MnOx film, resulting in poor conductivity.
Some embodiments of the present disclosure provide a method for manufacturing a semiconductor device, in which a recess such as a trench is formed in an insulating film, a metal oxide film such as a MnOx film is formed in the recess, and a conductive film such as Cu is formed thereon, whereby sufficient conductivity, desired properties, and high production yield can be obtained.
According to an embodiment of the present disclosure, a method for manufacturing a semiconductor device is provided. The method includes: forming an insulating film on a substrate where a first conductive film is formed; forming a recess in the insulating film such that the first conductive film is exposed in a portion of the recess; forming a metal oxide film to cover the insulating film and the first conductive film after forming a recess; performing a hydrogen radical treatment of irradiating the substrate with atomic hydrogen after forming a metal oxide film; and forming a second conductive film in the recess.
According to another embodiment of the present disclosure, a method for manufacturing a semiconductor device is provided. The method includes: forming an insulating film on a substrate where a first conductive film is formed; forming a recess in the insulating film such that the first conductive film is exposed in a portion of the recess; forming a metal oxide film to cover the insulating film and the first conductive film after forming a recess; performing an annealing process of heating the substrate in a reducing atmosphere or an inert gas atmosphere after forming a metal oxide film; performing a hydrogen radical treatment to irradiate the substrate with atomic hydrogen after performing an annealing process; and forming a second conductive film in the recess after performing a hydrogen radical treatment.
According to another embodiment of the present disclosure, a method for manufacturing a semiconductor device is provided. The method includes: forming an insulating film on a substrate where a first conductive film is formed; forming a recess in the insulating film such that the first conductive film is exposed in a portion of the recess; forming a metal oxide film to cover the insulating film and the first conductive film after forming a recess; performing an annealing process of heating the substrate in a reducing atmosphere or an inert gas atmosphere after forming a metal oxide film is formed; performing a wet etching process of removing the metal oxide film formed on the first conductive film after performing an annealing process; and forming a second conductive film in the recess after performing a wet etching process.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.
Hereinafter, details for performing the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments, and various modifications and replacements can be made to the following embodiments without departing from the scope of the present disclosure.
In addition, like parts will be assigned like reference numerals, and redundant description will be omitted. Further, a manganese oxide may be in the form of, but not limited to, MnO, Mn3O4, Mn2O3, MnO2 or the like depending on a valence number. Here, unless otherwise stated, all of these forms are represented by MnO. When the manganese oxide is represented by MnOx, x denotes a number between 1 and 2 inclusive. A Mn silicate may be in the form of Mn2SiO4 or Mn7SiO12 in addition to MnSiO3. Here, unless otherwise stated, all of these forms are represented by MnSixOy, wherein x and y denote positive numbers.
Further, in the embodiments, a hydrogen radical treatment indicates a process of generating atomic hydrogen by remote plasma, plasma, a heating filament or the like and irradiating a predetermined surface of a substrate or the like with the generated atomic hydrogen.
Further, in the embodiments, for a conversion process into a silicate by reacting with SiO2 of an underlying layer by an annealing (heat treatment) process, when an object to be processed is Mn, MnSiO3 is formed by an O2 annealing process. In the case of MnO, MnSiO3 is formed by an inert gas annealing process. In case of Mn3O4, Mn2O3 or MnO2, MnSiO3 is formed by a reducing atmosphere annealing process using a reducing gas such as hydrogen, CO, amine or its analogues (NR1R2R3), hydrazine or its analogues (N2R4R5R6R7) (wherein R1 to R7 are hydrogen (H) or hydrocarbon). The present disclosure is based on the above-described knowledge.
A semiconductor device manufacturing apparatus in accordance with an embodiment will be described. A wafer W may refer to a substrate or a substrate on which a film is formed.
A transfer mechanism 131 having a pickup that can be bended and extended to transfer wafers W is provided in the common transfer chamber 121. Further, an inlet side transfer mechanism 132 having a pickup that can be bended and extended to transfer wafers W is provided in the inlet side transfer chamber 124. The inlet side transfer mechanism 132 is supported on a guide rail 133 provided in the inlet side transfer chamber 124 to move slidably along the guide rail 133.
A wafer W is, by way of example, but not limitation, is a silicon wafer and is accommodated in the cassette receptacle 127. The wafer W is transferred from the inlet port 125 into the first load lock chamber 122 or the second load lock chamber 123 by the inlet side transfer mechanism 132. Then, the wafer W transferred into the first load lock chamber 122 or the second load lock chamber 123 is transferred into the four processing apparatuses 111 to 114 by the transfer mechanism 131 provided in the common transfer chamber 121. Further, the wafer W is also transferred between the four processing apparatuses 111 to 114 by the transfer mechanism 131. As the wafer W is moved between the four processing apparatuses 111 to 114, the wafer W is processed in the respective processing apparatuses 111 to 114. The above-mentioned transfer and processing of the wafer W may be controlled by a system controller 134 (control unit), and programs for implementing the system control or the like are stored in a storage medium 136.
In addition, the system controller 134 is implemented by a CPU of any computer, a memory, a program loaded in the memory, a memory unit for storing the program, such as a hard disc, and any combination of hardware and software through an interface for connecting to networks. Further, it is understood by a person skilled in the art that there are various modifications to its implementing method and apparatus.
In the present embodiment, among the four processing apparatuses 111 to 114, the first processing apparatus 111 is configured to form a MnOx film and includes a gas supply system for supplying film forming raw material gases into a processing space. The second processing apparatus 112 is configured to perform a hydrogen radical treatment, an inert gas annealing process or a reducing atmosphere annealing process and is provided with a gas supply system for supplying necessary gases into a processing space. The third processing apparatus 113 is configured to form a Ru film and is provided with a gas supply system for supplying film forming raw material gases into a processing space. The fourth processing apparatus 114 is configured to form a metal film such as a Cu film and is provided with a gas supply system for supplying film forming raw material gases into a processing space.
Connected to the second processing apparatus 112 is a remote plasma generating unit 120 configured to generate atomic hydrogen. By irradiating the wafer W with the atomic hydrogen that is generated by allowing hydrogen to pass through the remote plasma generating unit 120, a hydrogen radical treatment is performed. Here, it may be possible to employ a configuration in which the plasma generating unit is provided within the second processing apparatus 112 as long as the atomic hydrogen can be generated. Still alternatively, it may be possible to set up a configuration in which a heating filament is provided within the second processing apparatus 112 and atomic hydrogen is generated by heating. In addition, the reducing atmosphere annealing process may be performed in the second processing apparatus 112 by supplying hydrogen into a chamber of the second processing apparatus 112 and heating it. Further, before the MnOx film is formed in the first processing apparatus 111, a pre-process (for example, a degassing process) may be performed on the wafer W in the first processing apparatus 111 or the like. An oxidizing atmosphere annealing process may be performed, for example, in the third processing apparatus 113.
As shown in
Now, a method for manufacturing a semiconductor device in accordance with the embodiment will be discussed with reference to
First, at Step S102, an insulating film to be used as an interlayer insulating film is formed (insulating film forming process). Specifically, first, there is prepared a configuration in which a first conductive film (wiring layer) 212 made of copper or the like is formed on a surface of an insulating layer 211 which is formed on a substrate 210 such as a silicon substrate, as illustrated in
Subsequently, stacked on such a configuration are a diffusion preventing film 213 such as SiCN and an insulating film 214 made of SiO2 or the like to be used as an interlayer insulating film, as shown in
Then, at Step S104, a recess (opening) 215 is formed in the insulating film 214 and the diffusion preventing film 213 (recess forming process). Specifically, as shown in
Next, at Step S106, a degassing process, a cleaning process or the like is performed as a pre-process, so that the inside of the recess 215 is cleaned. As such a cleaning process, a H2 annealing process, a H2 plasma process, an Ar plasma process, and a dry cleaning process using organic acid may be employed.
In addition, the degassing process by heating is performed under the following conditions of: an inert gas atmosphere such as N2, Ar or He, a wafer temperature of 250 to 400 degrees C., a pressure of 13 to 2670 Pa, and a processing time of 30 to 300 seconds, for example, under the following conditions of: an Ar atmosphere, a wafer temperature of 300 degrees C., a pressure of 1330 Pa, and a processing time of 120 seconds.
Further, removal of native copper oxide by a H2 annealing process is performed under the following conditions of: a H2 atmosphere (wherein an inert gas such as N2, Ar or He may be added thereto, and also, a concentration of H2 may be 1 to 100 vol %), a wafer temperature of 250 to 400 degrees C., a pressure of 13 to 2670 Pa, and a processing time of 30 to 300 seconds, for example, under the following conditions of: a forming gas (3% H2+97% Ar) atmosphere, a wafer temperature of 300 degrees C., a pressure of 1330 Pa, and a processing time of 120 seconds.
Then, at Step S108, a metal oxide film is formed (metal oxide film forming process). In the embodiment, the metal oxide film may be a film containing Mn, such as a MnOx film. The metal oxide film may be formed by ALD. Specifically, as shown in
In addition, the MnOx film may be formed by thermal CVD or plasma CVD without limitation to the above-described ALD. In this case, specifically, the substrate 210 is heated to a temperature of 150 to 400 degrees C., for example, 200 degrees C., and the MnOx film is formed by supplying a Mn precursor of (EtCp)2. Thus, the MnOx film is formed on the side surface 215d of the recess 215 and the like. However, when the native oxide film (CuOx) of the Cu surface is not completely removed but remains, a reaction between the Mn precursor and the CuOx causes the MnOx film to be formed on the bottom surface of the recess at which Cu is exposed.
As a Mn precursor other than (EtCp)2Mn, the following are used:
Here, R, R1, R2, and R3 are alkyl groups represented by —CnH2n+1 (where n is an integer greater than or equal to 0), and Z is an alkylene group represented by —C—H2n— (where n is an integer greater than or equal to 0). Among them, (EtCp)2Mn[═Mn(C2H5C5H4)2] may be used in that it is liquid at a room temperature, has a vapor pressure sufficient to supply bubbles, and has high thermal stability.
In addition, a reaction gas other than H2O may include an oxygen-containing gas, for example, N2O, NO2, NO, O2, O3, H2O2, CO, CO2, alcohol, aldehyde, carboxylic acid, carboxylic acid anhydride, ester, organic acid ammonium salt, organic acid amine salt, organic acid amide, and organic acid hydrazide. Further, combinations of the plurality of oxygen-containing gases may be used. It is also noted that a reaction gas that is liquid at a room temperature is supplied into the processing chamber after heating and is evaporated into a gas or vapor state.
Also, if the MnOx film 220 is used as the oxide film as described in the embodiment, the oxide film may be formed of another metal oxide or may be formed of material including an oxide of one or more elements selected among Mg, Al, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Ge, Sr, Y, Zr, Nb, Mo, Rh, Pd, Sn, Ba, Hf, Ta and Ir. Among them, Mn may be used in that it may form a silicate, be solid-soluble with Cu, have a large diffusion coefficient for Cu (have a high diffusion rate in Cu), and be soluble even in acid having no (or weak) oxidizing power.
Then, at Step S110, a hydrogen radical treatment is performed (hydrogen radical treatment process). Specifically, atomic hydrogen is generated by remote plasma, plasma, a heating filament or the like, and the surface of the MnOx film 220 is irradiated with the generated atomic hydrogen. In the embodiment, the atomic hydrogen is generated by the remote plasma generated in the remote plasma generating unit 120 shown in
Accordingly, as shown in
Further, in the hydrogen radical treatment in accordance with the embodiment, the heating temperature of the substrate 210 may be in a range of room temperature to 450 degrees C., may be in a range of 200 degrees C. to 400 degrees C., or may be 300 degrees C. or so. In addition, as for the gas atmosphere, the concentration of H2 in Ar may be in a range of 1 to 20%, or may be in a range of 3 to 15%. Further, the gas atmosphere may be formed of H2: 10% and Ar: 90%. Further, the processing pressure may be in a range of 10 to 500 Pa, may be in a range of 20 to 100 Pa, or may be 40 Pa. The input power may be in a range of 1 to 5 kW, may be in a range of 1.5 to 3 kW, or may be 2.5 kW. Further, the processing time may be in a range of 5 to 300 seconds, may be in a range of 10 to 100 seconds, or may be 60 seconds. Further, a degassing process (heat treatment process) may be performed between the formation of the MnOx film 220 at Step S108 and the hydrogen radical treatment at Step S110.
At Step S112, an annealing process is performed in an oxidizing atmosphere (annealing process). Specifically, in the embodiment, the annealing process is performed under the following conditions of: an atmosphere having a small amount of an oxygen-containing gas added to an inert gas such as helium (He), argon (Ar), neon (Ne), nitrogen (N2), for example, a gas atmosphere having O2 of 10 ppb to 3 vol % added to Ar, a processing pressure of 13 to 2670 Pa, a processing time of 30 to 1800 seconds, and a substrate heating temperature of 200 to 500 degrees C. or 250 to 350 degrees C. Here, as an oxygen-containing gas other than O2, for example, H2O, N2O, NO2, NO, O3, H2O2, CO or CO2 may be used.
Further, when the insulating film 214 and the like are degassed of the oxygen-containing gas such as H2O by heating the wafer, even if the annealing is performed without supplying an oxygen-containing gas from the outside of the wafer, it is possible to obtain the same effect as when the annealing is performed with the oxygen-containing gas supplied from the outside. When the insulating film and the like are degassed of the oxygen-containing gas by heating the wafer, the annealing may be performed while an inert gas is supplied. In other words, an oxygen-containing gas may be supplied into the wafer processing space from the gas supply system of the processing apparatus, or the components contained in the underlying layer may be removed from the underlying layer and used as the oxygen-containing gas.
It has been described above that the MnOx film 222 formed on the side surface 215d of the recess 215 and the like is entirely reduced by the hydrogen radical treatment at Step S110 and converted into the Mn film 222a. However, depending on the conditions of the hydrogen radical treatment or a film thickness or film quality of the MnOx film 222, there are occasions in which the MnOx film 222 is not entirely reduced and converted into the Mn film 222a. For example, there may be a case where only the MnOx film 222 on the top layer side which is exposed and is not in contact with the insulating film 214 is reduced by the hydrogen radical treatment and converted into the Mn film 222a, while the MnOx film 222 on the bottom layer side which is in contact with the insulating film 214 is not influenced by the reduction action of the hydrogen radical and reacts with the silicon oxide in the insulating film 214 by the heat in the hydrogen radical treatment to form the Mn silicate (MnSixOy) film 222b. In such a case, the formation of Mn silicate is already completed, and the Mn silicate film 222b is finally formed between the insulating film 214 and the second conductive film 230. Thus, the oxidizing atmosphere annealing process at Step S112 may be omitted.
Accordingly, as shown in
In addition, the reaction in which the Mn film 222a is converted into a silicate and becomes the Mn silicate film 222b will be described in detail based on the following description. Specifically, the mechanism that the Mn film 222a reacts with the SiO2 component contained in the underlying layer and is converted into a silicate to become the Mn silicate film 222b by annealing the wafer W in the oxidizing atmosphere will be described with reference to chemical reaction formulas.
A chemical reaction formula of metal manganese (Mn) and a silicon dioxide (SiO2) is shown below. In addition, respective chemical reaction formulas show an equilibrium state at 300K. Further, the heat quantity of the right side means a heat quantity (kJ) per mol of manganese (Mn) and indicates the Gibbs free energy change amount (hereinafter, referred to as Gr change amount (ΔGr)). In this regard, the Gibbs free energy tends to voluntarily decrease. Thus, it is known that a chemical reaction having a negative Gr change amount occurs voluntarily but a chemical reaction having a positive Gr change amount does not occur voluntarily. A commercial thermodynamic database was used in the following thermodynamic calculation.
Mn+SiO2→MnSiO3 (A)
The chemical reaction formula (A) has the left side and the right side unbalanced in the amount of oxygen and thus is not established as a reaction formula. Therefore, it can be appreciated that a reaction cannot proceed from the left side to the right side, in other words, there is no possibility of conversion into a silicate. From the foregoing, since Mn is not converted into a silicate by merely performing a heat treatment, Mn remains.
Next, when oxygen (O2) is introduced, a chemical reaction formula of Mn and SiO2 is shown below:
2Mn+2SiO2+O2→2MnSiO3−380(ΔGr(kJ/Mn-mol)) (B)
From the chemical reaction formula (B), in the case of Mn, as oxygen is supplied, a reaction can proceed from the left side to the right side, in other words, there is a possibility of conversion into a silicate. From the foregoing, due to the introduction of oxygen, Mn may be converted into a silicate and become MnSixOy. In addition, it is confirmed by thermodynamic calculation that the reaction of forming a silicate may proceed with H2O or CO2 in addition to O2.
At Step S114, the second conductive film 230 is formed (second conductive film forming process). The second conductive film is typically a metal film such as Cu. Specifically, as illustrated in
Thereafter, as required, a planarizing process may be performed by CMP (Chemical Mechanical Polishing) or the like, thereby removing the second conductive film 230 and the Mn silicate film 222b exposed from the recess 215. By repeating the above-described processes, a required multilayer wiring structure can be formed, and a semiconductor device having a multilayer wiring structure can be manufactured.
In the above processes, the formation of the MnOx film 220 at Step S108, the hydrogen radical treatment at Step S110 and the oxidizing atmosphere annealing process at Step S112 may be performed in the same chamber (processing apparatus) or in different chambers (processing apparatuses), respectively. Further, from a safety standpoint, the hydrogen radical treatment at Step S110 and the oxidizing atmosphere annealing process at Step S112 may be performed in different chambers (processing apparatuses), respectively. When the hydrogen radical treatment at Step S110 and the oxidizing atmosphere annealing process at Step S112 are performed in the same chamber (processing apparatus), H2O or CO2 may be used as the oxygen-containing gas used in the oxidizing atmosphere annealing process in light of the reactivity with hydrogen. In order to supply the oxygen-containing gas, the oxygen-containing gas may be supplied into the wafer processing space from the gas supply system of the processing apparatus, or the components contained in the underlying layer may be removed from the underlying layer to be used as the oxygen-containing gas.
According to the manufacturing method of the present embodiment, since the Mn silicate film 222b is formed between the insulating film 214 and the second conductive film 230, it is possible to prevent Cu and the like contained in the second conductive film 230 from being diffused into the insulating film 214 and also prevent O2 or H2O contained in the insulating film 214 from being diffused into the second conductive film 230. Further, since the second conductive film 230 is in contact with copper and the like constituting the first conductive film 212, it is possible to obtain sufficient conductivity and thus suppress the occurrence of poor conductivity. Thus, it is possible to miniaturize a multilayer Cu wiring and obtain a miniaturized semiconductor device having a high speed. As a consequence, a compact-sized electronic device having a high speed and a high reliability can be obtained.
Next, with reference to
The present embodiment is different from the first embodiment in that a MnSiO3 is formed by reducing atmosphere annealing using a reducing gas such as hydrogen, CO, amine or its analogues (NR1R2R3), hydrazine or its analogues (N2R4R5R6R7) (wherein R1 to R7 are hydrogen (H) or hydrocarbon) or inert gas annealing using an inert gas, instead of the oxidizing atmosphere annealing.
First, by the same processing sequences (Steps S202 to 208) as Steps S102 to 108 (
Next, at Step S210, an annealing process using an inert gas or a reducing gas is performed (annealing process). Specifically, in the embodiment, the reducing atmosphere annealing process is performed in an atmosphere having a reducing gas such as hydrogen, CO, amine or its analogues (NR1R2R3), or hydrazine or its analogues (N2R4R5R6R7) added to an inert gas such as helium (He), argon (Ar), neon (Ne), or nitrogen (N2). Here, R1 to R7 are hydrogen (H) or hydrocarbon. An analogue of amine (NH3) may include, for example, methylamine (CH3NH2), ethylamine (C2H5NH2), dimethylamine ((CH3)2NH), trimethylamine ((CH3)3N) and the like. An analogue of hydrazine (N2H4) may include, for example, methylhydrazine (CH3NNH3), dimethylhydrazine ((CH3)2NNH2), and trimethylhydrazine ((CH3)3NNH).
For example, when hydrogen is used as the reducing gas, the annealing process is performed under the following conditions of: a gas atmosphere of H2: 3% and Ar: 97%, a processing pressure of 13 to 2670 Pa, a processing time of 30 to 1800 seconds, and a substrate heating temperature of 200 to 450 degrees C. or 250 to 350 degrees C.
Further, for convenience, the reducing atmosphere annealing process is illustrated in the figures, but an inert gas annealing process may be performed instead of the reducing atmosphere annealing process when MnOx is formed of only MnO.
Accordingly, as shown in
Next, the reaction in which the MnOx film 222 is converted into a silicate and becomes the Mn silicate film 222b will be described in detail based on the following description. Specifically, the mechanism that, the MnOx film 222 reacts with the SiO2 component contained in the underlying layer and is converted into a silicate and becomes the Mn silicate film 222b by performing an annealing process in the reducing atmosphere will be described with reference to chemical reaction formulas.
Chemical reaction formulas of a manganese oxide (MnO and Mn2O3) and a silicon dioxide (SiO2) are shown below. In addition, the respective chemical reaction formulas show an equilibrium state at 300K. Further, the heat quantity of the right side means a heat quantity (kJ) per mol of manganese (Mn) and indicates the Gibbs free energy change amount (hereinafter, referred to as Gr change amount (ΔGr)) by a two-digit effective number. In this regard, the Gibbs free energy tends to voluntarily decrease. Thus, it is known that a chemical reaction having a negative Gr change amount occurs voluntarily but a chemical reaction having a positive Gr change amount does not occur voluntarily. A commercial thermodynamic database was used in the following thermodynamic calculation.
MnO+SiO2→MnSiO3−21(ΔGr(kJ/Mn-mol)) (1)
2Mn2O3+4SiO2→4MnSiO3+O2+57(ΔGr(kJ/Mn-mol)) (2)
2Mn2O3+2SiO2→2Mn2SiO4+O2+53(ΔGr(kJ/Mn-mol)) (3)
From the chemical reaction formula (1), in the case of MnO, a reaction can proceed from the left side to the right side, in other words, there is a possibility of conversion into a silicate. In addition, it can be appreciated from the chemical reaction formulas (2) and (3) that a reaction cannot proceed from the left side to the right side, in other words, there is no possibility of conversion into a silicate. From the foregoing, Mn2O3 is not converted into a silicate by merely performing a heat treatment and, therefore, Mn2O3 remains.
Next, when hydrogen (H) is introduced, chemical reaction formulas of Mn2O3 and SiO2 are shown below:
Mn2O3+2SiO2+H2→2MnSiO3+H2O−58(ΔGr(kJ/Mn-mol)) (4)
Mn2O3+SiO2+H2→Mn2SiO4+H2O−62(ΔGr(kJ/Mn-mol)) (5)
From the chemical reaction formulas (4) and (5), when hydrogen (H) is introduced, a reaction can proceed from the left side to the right side even if Mn2O3 is used, i.e., there is a possibility of conversion into a silicate. From the foregoing, due to the introduction of hydrogen, Mn2O3 is converted into a silicate and can become MnSixOy.
Next, chemical reaction formulas of Mn2O3 are shown below:
2Mn2O3→4MnO+O2+78(ΔGr(kJ/Mn-mol)) (6)
Mn2O3+H2→2MnO+H2O−37(ΔGr(kJ/Mn-mol)) (7)
From the chemical reaction formula (6), when no hydrogen in introduced, Mn2O3 cannot become MnO. As shown in the chemical reaction formulas (2) and (3), Mn2O3 cannot be converted into a silicate without hydrogen. Therefore, when no hydrogen is introduced, Mn2O3 cannot be converted into a silicate and cannot become a manganese silicate (MnSixOy).
On the contrary, from the chemical reaction formula (7), due to the introduction of hydrogen, Mn2O3 may become MnO. As shown in the chemical reaction formula (1), since MnO can be converted into a silicate and become a manganese silicate (MnSixOy), Mn2O3 can be converted into a silicate and become a manganese silicate (MnSixOy) by the introduction of hydrogen.
Subsequently, when CO is introduced as the reducing gas, a chemical reaction formula is shown below:
Mn2O3+CO→2MnO+CO2−51(ΔGr(kJ/Mn-mol)) (a1)
Also, as shown in the chemical reaction formula (1), MnO can be converted into a silicate by annealing.
Mn2O3+2SiO2+CO→2MnSiO3+CO2−72(ΔGr(kJ/Mn-mol)) (a2)
Mn2O3+SiO2+CO→Mn2SiO4+CO2−76(ΔGr(kJ/Mn-mol)) (a3)
Subsequently, when NH3 is introduced as the reducing gas, a chemical reaction formula is shown below:
Mn2O3+0.5NH3→2MnO+0.25N2O+0.75H2O+9.0(ΔGr(kJ/Mn-mol)) (b1)
Here, if the temperature is 500K or more, ΔGr becomes negative. Also, as shown in the chemical reaction formula (1), MnO may be converted into a silicate by annealing.
Mn2O3+2SiO2+0.5NH3→2MnSiO3+0.25N2O+0.75H2O−12(ΔGr(kJ/Mn-mol)) (b2)
Mn2O3+SiO2+0.5NH3→Mn2SiO4+0.25N2O+0.75H2O−16(ΔGr(kJ/Mn-mol)) (b3)
Subsequently, when N2H4 is introduced as the reducing gas, the chemical reaction formulas are shown below:
Mn2O3+2SiO2+0.33N2H4→2MnSiO3+0.33N2O+0.67H2O−29(ΔGr(kJ/Mn-mol)) (c1)
Mn2O3+SiO2+0.33N2H4→Mn2SiO4+0.33N2O+0.67H2O−33(ΔGr(kJ/Mn-mol)) (c2)
As described above, it can be seen from the chemical reaction formulas (a2), (a3), (b2), (b3), (c1) and (c2) that even when CO, NH3 or N2H4 is introduced as the reducing gas, Mn2O3 can be converted into a silicate and become a Mn silicate (MnSixOy).
Then, at Step S212, a hydrogen radical treatment is performed (hydrogen radical treatment process). The sequence of the hydrogen radical treatment is the same as the first embodiment, and thus, the details thereof will be omitted.
Accordingly, as shown in
Then, at Step S214, as shown in
Thereafter, as required, a planarizing process may be performed by CMP or the like, thereby removing the second conductive film 230 and the Mn silicate film 222b exposed from the recess 215. By repeating the above-described processes, a required multilayer wiring structure can be formed, and a semiconductor device having a multilayer wiring structure can be manufactured.
In the above processes, the formation of the MnOx film 220 at Step S208, the inert gas annealing process or the reducing atmosphere annealing process at Step S210, and the hydrogen radical treatment at Step S212 may be performed in the same chamber (processing apparatus), or in different chambers (processing apparatuses), respectively. In addition, the MnOx film 220 is formed at Step S208 while hydrogen is introduced, so that the film forming process at Step S208 and the annealing process at Step S210 may be simultaneously performed.
According to the manufacturing method of the present embodiment, since the Mn silicate film 222b is formed between the insulating film 214 and the second conductive film 230, it is possible to prevent Cu and the like contained in the second conductive film 230 from being diffused into the insulating film 214 and also prevent O2 or H2O contained in the insulating film 214 from being diffused into the second conductive film 230. Further, since the second conductive film 230 is in contact with copper and the like constituting the first conductive film 212, it is possible to obtain sufficient conductivity and thus suppress the occurrence of poor conductivity. Accordingly, it is possible to miniaturize a multilayer Cu wiring and obtain a miniaturized semiconductor device having a high speed. As a consequence, a compact-sized electronic device having a high speed and a high reliability can be obtained. In addition, descriptions other than the foregoing are the same as the first embodiment.
The present embodiment is different from the first embodiment in that a third conductive film (Ru film), which functions as an adhesion layer to improve adhesion between the Mn silicate (MnSixOy) film 222b and the second conductive film 230, is formed therebetween. Ru (002) has a lattice constant of 2.14 angstroms, and Cu (111) has a lattice constant of 2.09 angstroms. Since Ru and Cu are close to each other in the lattice constant and have good wettability to each other, high adhesion and good fillability of the second conductive film 230 such as Cu into the recess 215 can be expected.
Next, with reference to
First, through the same processing sequences (Steps S302 to 310) as Steps S102 to S110 (
Then, at Step S312, a third conductive film (Ru film) 240 is formed (third conductive film forming process). Specifically, as shown in
Next, at Step S314, an annealing process is performed in an oxidizing atmosphere (annealing process). Specifically, in the embodiment, the annealing process is performed under the following conditions of: an atmosphere having a small amount of an oxygen-containing gas added to an inert gas such as helium (He), argon (Ar), neon (Ne), nitrogen (N2), for example, a gas atmosphere having O2 of 10 ppb to 3 vol % added to Ar, a processing pressure of 13 to 2670 Pa, a processing time of 30 to 1800 seconds, and a substrate heating temperature of 200 to 500 degrees C. or 250 to 350 degrees C. Here, as an oxygen-containing gas other than O2, for example, H2O, N2O, NO2, NO, O3, H2O2, CO, or CO2 may be used.
Further, when the insulating film 214 and the like are degassed of the oxygen-containing gas such as H2O by heating the wafer, even if the annealing is performed without supplying an oxygen-containing gas from the outside of the wafer, it is possible to obtain the same effect as when the annealing is performed with the oxygen-containing gas supplied from the outside. When the insulating film and the like are degassed of the oxygen-containing gas by heating the wafer, the annealing may be performed while an inert gas is supplied. In other words, an oxygen-containing gas may be supplied into the wafer processing space from the gas supply system of the processing apparatus, or the components contained in the underlying layer may be removed therefrom and used as the oxygen-containing gas.
Accordingly, as shown in
Further, in the embodiment, a predetermined level of vacuum or a predetermined oxygen partial pressure may be maintained between the hydrogen radical treatment at Step S310 and the formation of the third conductive film 240 at Step S312. For example, the vacuum may be maintained at 1×10−4 Pa or less. Accordingly, the hydrogen radical treatment at Step S310 and the formation of the third conductive film 240 at Step S312 may be performed in the same chamber as shown in
Further, between the hydrogen radical treatment at Step S310 and the formation of the third conductive film 240 at Step S312, there may be a cooling process for cooling the substrate 210 to a temperature less than or equal to a Ru film forming temperature, for example, to room temperature. The formed third conductive film 240 has a film thickness of 0.5 to 5 nm, and the third conductive film 240 may be formed by ALD, other than CVD. In addition, although the case that the Ru film as the third conductive film 240 is formed has been described in the embodiment, the third conductive film 240 may be made of a metal material, other than Ru, for example, a material containing one or more elements selected among Fe, Co, Ni, Rh, Pd, Os, Ir and Pt. Furthermore, a material containing one or more elements selected among platinum group elements may be used. They have a good adhesion to Cu and are electrically conductive, and thus, have the same function as the seed Cu layer.
At Step S316, as shown in
Thereafter, as required, a planarizing process may be performed by CMP or the like, thereby removing the second conductive film 230 and the Mn silicate film 222b exposed from the recess 215. By repeating the above-described processes, a required multilayer wiring structure can be formed, and a semiconductor device having a multilayer wiring structure can be manufactured.
In the above processes, the formation of the MnOx film 220 at Step S308 and the hydrogen radical treatment at Step S310 may be performed in the same chamber (processing apparatus) or in different chambers (processing apparatuses) respectively.
According to the manufacturing method of the present embodiment, since the third conductive film 240 and the Mn silicate film 222b is formed between the insulating film 214 and the second conductive film 230, it is possible to prevent Cu and the like contained in the second conductive film 230 from being diffused into the insulating film 214 and also prevent O2 or H2O contained in the insulating film 214 from being diffused into the second conductive film 230. Further, since the second conductive film 230 is in contact with the first conductive film 212 via the third conductive film 240 which is a metal material having high conductivity, it is possible to obtain sufficient conductivity and thus suppress the occurrence of poor conductivity. In addition, since the interposition of the third conductive film 240 causes wettability with the second conductive film 230 (Cu) to be improved, it is possible to expect enhanced fillability of the second conductive film 230 (Cu) along with improved adhesion. Accordingly, it is possible to miniaturize a multilayer Cu wiring and obtain a highly miniaturized semiconductor device having a high speed. As a consequence, a compact-sized electronic device having a high speed and a high reliability can be obtained. In addition, descriptions other than the foregoing are the same as the first embodiment. Further, the present embodiment may be applied in the method for manufacturing the semiconductor device in accordance with the second embodiment. In such a case, the film forming process of the third conductive film 240 at Step S312 is interposed between the hydrogen radical treatment process at Step S212 and the film forming process of the Cu film 230 at Step S214.
The present embodiment is different from the second embodiment in that the MnOx film 221 formed on the bottom of the recess 215 is selectively removed by wet etching.
Next, with reference to
First, by the same processing sequences (Steps S402 to S408) as Steps S102 to S108 (
Then, at Step S410, an inert gas or hydrogen-containing gas annealing process or a reducing atmosphere annealing process is performed (inert gas annealing process or reducing atmosphere annealing process). The sequence thereof is the same as the second embodiment (Step S210), and thus, the details thereof will be omitted.
Accordingly, as shown in
Then, at Step S412, a wet etching process is performed using hydrochloric acid. Specifically, after the inert gas annealing process or the reducing atmosphere annealing process is performed, immersion in hydrochloric acid is performed, whereby, as shown in
Further,
Then, as shown in
Thereafter, as required, a planarizing process may be performed by CMP or the like, thereby removing the second conductive film 230 and the Mn silicate film 222b exposed from the recess 215. By repeating the above-described processes, a required multilayer wiring structure can be formed, and a semiconductor device having a multilayer wiring structure can be manufactured.
In the above processes, the formation of the MnOx film 220 at Step S408 and the inert gas annealing process or the reducing atmosphere annealing process at Step S410 may be performed in the same chamber (processing apparatus), or may be performed in different chambers (processing apparatuses) respectively. In addition, the MnOx film 220 is formed at Step S408 while hydrogen is introduced, so that the film forming process at Step S408 and the annealing process at Step S410 may be simultaneously performed. Also, a chamber (processing apparatus) in which the wet etching is performed is connected to the common transfer chamber 121 to form a cluster tool.
According to the manufacturing method of the present embodiment, since the Mn silicate film 222b is formed between the insulating film 214 and the second conductive film 230, it is possible to prevent Cu and the like contained in the second conductive film 230 from being diffused into the insulating film 214 and also prevent O2 or H2O contained in the insulating film 214 from being diffused into the second conductive film 230. Further, since the second conductive film 230 is in contact with copper and the like constituting the first conductive film 212, it is possible to obtain sufficient conductivity and thus suppress the occurrence of poor conductivity. In the embodiment, since the MnOx film 221 formed on the bottom 215c of the recess 215 is previously removed by the wet etching, and thus, Mn is not diffused into the first conductive film 212, it is possible to make wiring resistance even lower. Accordingly, it is possible to miniaturize a multilayer Cu wiring and obtain a highly miniaturized semiconductor device having a high speed. As a consequence, a compact-sized electronic device having a high speed and a high reliability can be obtained. In addition, descriptions other than the foregoing are the same as the first or second embodiment.
Without limitation to the formation of the above-described MnOx film, in some cases, the present disclosure may be partially applied to a case where a metal Mn film is formed by a film forming means such as thermal ALD, thermal CVD, plasma ALD, or plasma CVD. For example, a Mn film is formed by heating the substrate 210 to 200 to 400 degrees C., for example, 300 degrees C., and supplying a Mn precursor such as the above-described amideaminoalkane-based manganese compound. Thus, in general, the Mn film is formed on the bottom 215c of the via hole 215b and the side surface 215d of the recess 215 and the like. However, when the native oxide film (CuOx) cannot be completely removed from the Cu surface but remains thereon, in some cases, the reaction of the formed metal Mn and CuOx may cause a MnOx film to be formed on the bottom of the recess at which Cu is exposed. At that time, by the hydrogen radical treatment to irradiate the substrate with atomic hydrogen, the MnOx deposited on Cu may be reduced and simultaneously diffused into Cu (the underlying first conductive film) and dissipated, whereby the MnOx is removed.
In addition, while the embodiments of the present disclosure have been described, they are not intended to limit the present disclosure thereto.
For example, an example in which after the oxidizing atmosphere annealing process at Step S112 of
In addition, for example, an example in which after the formation of the Ru film (third conductive film) at Step S312 of
Further, the processes of the respective embodiments may be appropriately combined. For example, in the sequence of the second embodiment, the formation of the Ru film (third conductive film) at Step S312 of
The claims of Japanese Patent Application No. 2012-159652, filed Jul. 18, 2012, are prerequisites for the following (Item 1) to (Item 27).
The present disclosure also includes the following (Item 1) to (Item 27).
A method for manufacturing a semiconductor device, including:
an oxide film forming process of forming an oxide film made of a metal oxide in an opening (recess) formed in an insulating film, the insulating film being formed on a surface of a substrate;
a hydrogen radical treatment process of irradiating the substrate with atomic hydrogen after the oxide film forming process;
an oxygen annealing process of heating the substrate while oxygen is supplied after the oxide film forming process; and
A method for manufacturing a semiconductor device, including:
an oxide film forming process of forming an oxide film made of a metal oxide in an opening formed in an insulating film, the insulating film being formed on a surface of a substrate;
a hydrogen radical treatment process of irradiating the substrate with atomic hydrogen after the oxide film forming process;
an electrode forming process of forming an electrode made of metal in the opening after the oxide film forming process; and
an oxygen annealing process of heating the substrate while oxygen is supplied after the electrode forming process.
The method for manufacturing the semiconductor device of Item 1 or 2, wherein the oxygen annealing process is performed after the hydrogen radical treatment process.
A method for manufacturing a semiconductor device, including:
an oxide film forming process of forming an oxide film made of a metal oxide in an opening formed in an insulating film, the insulating film being formed on a surface of a substrate;
a hydrogen annealing process of heating the substrate while hydrogen is supplied after the oxide film forming process;
a hydrogen radical treatment process of irradiating the substrate with atomic hydrogen after the hydrogen annealing process; and
an electrode forming process of forming an electrode made of metal in the opening after the hydrogen annealing process and the hydrogen radical treatment process are performed.
The method for manufacturing the semiconductor device of any one of Items 1 to 4, wherein the hydrogen radical treatment process is performed while the substrate is heated.
The method for manufacturing the semiconductor device of any one of Items 1 to 5, wherein the atomic hydrogen is generated by remote plasma.
A method for manufacturing a semiconductor device, including:
an oxide film forming process of forming an oxide film made of a metal oxide in an opening formed in an insulating film, the insulating film being formed on a surface of a substrate;
a hydrogen annealing process of heating the substrate while hydrogen is supplied after the oxide film forming process;
a wet etching process of removing the oxide film from a bottom of the opening by wet etching after the hydrogen annealing process; and
an electrode forming process of forming an electrode made of metal in the opening after the wet etching process is performed.
The method for manufacturing the semiconductor device of Item 7, wherein etching liquid including any one of hydrochloric acid, acetic acid and citric acid is used for the wet etching.
The method for manufacturing the semiconductor device of Item 7, wherein the wet etching is performed using a neutral or acid chemical liquid.
The method for manufacturing the semiconductor device of Item 9, wherein the chemical liquid has an oxidation-reduction potential of less than or equal to 0.1 V.
The method for manufacturing the semiconductor device of Item 9, wherein the chemical liquid has an oxidation-reduction potential of greater than or equal to −1.2 V and less than or equal to 0.1 V.
The method for manufacturing the semiconductor device of any one of Items 1 to 11, wherein the oxide film is formed by ALD.
The method for manufacturing the semiconductor device of any one of Items 1 to 12, wherein the oxide film is formed of material including an oxide of one or more elements selected from a group including Mg, Al, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Ge, Sr, Y, Zr, Nb, Mo, Rh, Pd, Sn, Ba, Hf, Ta and Ir.
The method for manufacturing the semiconductor device of any one of Items 1 to 13, wherein the oxide film includes an oxide of Mn.
The method for manufacturing the semiconductor device of any one of Items 1 to 14, wherein a metal film (conductive film) forming process is performed after the hydrogen radical treatment process and the hydrogen annealing process or the oxygen annealing process are performed, and the electrode forming process is performed after the metal film forming process is performed, the metal film being formed of material including one or more elements selected from a group including Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt.
The method for manufacturing the semiconductor device of any one of Items 4, 7 and 15, wherein, instead of the hydrogen annealing process, an inert gas annealing process of heating the substrate while an inert gas is supplied is performed.
The method for manufacturing the semiconductor device of any one of Items 1 to 16, wherein, instead of the oxide film forming process, a film including Mn is formed, the film including Mn being formed by thermal CVD or plasma CVD.
The method for manufacturing the semiconductor device of any one of Items 1 to 17, wherein the electrode is formed of copper or material including copper.
The method for manufacturing the semiconductor device of any one of Items 1 to 18, wherein the electrode is formed by one or more methods selected among thermal CVD, thermal ALD, plasma CVD, plasma ALD, PVD, electroplating, electroless plating, and supercritical CO2.
A semiconductor device having a film structure formed by the method for manufacturing the semiconductor device of any one of Items 1 to 19.
A semiconductor device manufacturing apparatus having one or more chambers,
wherein an oxide film made of a metal oxide is formed in any one of the chambers,
wherein a hydrogen radical treatment process of performing an irradiation using atomic hydrogen is performed in any one of the chambers,
wherein an annealing process of performing a heating operation while hydrogen or oxygen or an inert gas is supplied is performed in any one of the chambers, and
wherein an electrode made of metal is formed in any one of the chambers.
The semiconductor device manufacturing apparatus of Item 21, wherein the oxide film is formed by ALD.
The semiconductor device manufacturing apparatus of Item 21 or 22, wherein the oxide includes an oxide of Mn.
A semiconductor device manufacturing apparatus having one or more chambers,
wherein a metal film is formed by thermal CVD or plasma CVD in any one of the chambers;
wherein a hydrogen radical treatment process of performing an irradiation using atomic hydrogen is performed in any one of the chambers;
wherein an annealing process of performing a heating operation while hydrogen or oxygen or an inert gas is supplied is performed in any one of the chambers; and
wherein an electrode made of metal is formed in any one of the chambers.
The semiconductor device manufacturing apparatus of Item 24, wherein the metal film is a film including Mn.
The semiconductor device manufacturing apparatus of Item 21 or 25, wherein the hydrogen radical treatment process and the annealing process of performing a heating operation while the hydrogen or oxygen or the inert gas is supplied are performed in the same chamber.
The semiconductor device manufacturing apparatus of Item 21 or 26, wherein the formation of the oxide film, the hydrogen radical treatment process, and the annealing process of performing a heating operation while the hydrogen or oxygen or the inert gas is supplied are performed in the same chamber.
According to a method for manufacturing a semiconductor device of the present disclosure, the semiconductor device is formed in such a manner that a recess such as a trench is formed in an insulating film, a metal oxide film such as a MnOx film is formed in the recess, and a conductive film such as Cu is formed thereon. Therefore, sufficient conductivity, desired properties, and high production yield can be obtained, and reliability can be improved.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-159652 | Jul 2012 | JP | national |
This application is a Continuation application of PCT International Application No. PCT/JP2013/069058, filed Jul. 11, 2013, which claimed the benefit of Japanese Patent Application No. 2012-159652, filed Jul. 18, 2012, the entire content of each of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2013/069058 | Jul 2013 | US |
| Child | 14598788 | US |
