Silicide formation method and semiconductor manufacturing equipment

Abstract

To grow a Zr silicide film to the desired film thickness.SOLUTION: When forming a Zr silicide film 49a on a base 46 of a wafer W, the surface of the base 46 is first activated by argon plasma treatment on the base 46 of the wafer W, and the Zr film 49 is formed on the activated surface of the base 46.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a method for forming a silicide and a semiconductor manufacturing apparatus. [Background technology]

[0002] For example, in logic ICs as semiconductor devices, titanium (Ti) silicide and nickel (Ni) silicide are used as contact materials for the source and drain. However, with the miniaturization of devices in recent years, the contact parts also shrink, and the resistance of the contact parts tends to increase. Therefore, in order to reduce the resistance of the contact parts, the use of zirconium (Zr) silicide, a low-resistance metal, as a contact material is being considered.

[0003] Such metal silicides are formed by subjecting a metal film formed by sputtering, vapor deposition, or ion plating on a silicon-based semiconductor substrate wafer to heat treatment. The heat treatment is carried out, for example, in a vacuum, a nitrogen gas atmosphere, or an inert gas (e.g., argon (Ar) gas) atmosphere at a temperature in the range of 400°C to 1200°C (particularly, in the range of 600°C to 1000°C) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2007 / 063908 Summary of the Invention [Problem to be solved by the invention]

[0005] The technique according to the present disclosure grows a Zr silicide film to a desired thickness. [Means for solving the problem]

[0006] One aspect of the technology disclosed herein is a silicide formation method for forming zirconium silicide on a substrate, the method comprising: an activation step of activating a surface of the substrate on which a zirconium film is to be formed by using argon plasma; and a metal film formation step of forming the zirconium film on the activated surface. Effect of the Invention

[0007] According to the technique of the present disclosure, the Zr silicide film can be grown to a desired thickness. [Brief description of the drawings]

[0008] [Figure 1] 1 is a plan view for explaining a configuration of a semiconductor manufacturing apparatus according to an embodiment of the technology disclosed herein; [Diagram 2] FIG. 3 is a schematic cross-sectional view showing the configuration of the Zr film formation chamber in FIG. 2. [Diagram 3] 2 is an enlarged partial cross-sectional view of the vicinity of a pattern on a wafer in which a wiring material is embedded, in the semiconductor manufacturing apparatus of FIG. 1. [Figure 4] FIG. 1 is a diagram for explaining the reason why a Zr film is difficult to be silicided. [Diagram 5] FIG. 1 is a diagram for explaining the reason why a Zr film is difficult to grow. [Figure 6] FIG. 1 is a diagram for explaining the reason why a Zr film is easily converted into a silicide by activation with Ar plasma. [Figure 7] FIG. 2 is a diagram for explaining the reason why activation by Ar plasma makes it easier for a Zr film to grow. [Figure 8] 1 is a flowchart showing a method for forming Zr silicide according to an embodiment of the present invention. [Figure 9] 11 is a flowchart showing a first modified example of the method for forming Zr silicide in accordance with the present embodiment. [Figure 10] 13 is a flowchart showing a second modified example of the method for forming Zr silicide in accordance with the present embodiment. [Figure 11]13 is a flowchart showing a third modified example of the method for forming Zr silicide in accordance with the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] However, when Zr silicide is formed on silicon on the surface of a wafer by the method of Patent Document 1, it has been confirmed that when the formation of Zr silicide progresses to a certain extent, no more Zr silicide is formed and the growth of the Zr silicide film becomes saturated, making it difficult to grow the Zr silicide film to a desired thickness.

[0010] In contrast, the technique according to the present disclosure activates the surface on which the Zr silicide is to be formed, thereby promoting the growth of the Zr silicide film.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the technology according to the present disclosure will now be described with reference to the accompanying drawings, in which: Fig. 1 is a plan view illustrating the configuration of a semiconductor manufacturing apparatus according to the present embodiment.

[0012] 1, a semiconductor manufacturing apparatus 10 includes a COR chamber 11 for performing a COR (Chemical Oxide Removal) process, an Ar plasma processing chamber 12 for performing an argon (Ar) plasma process, and a Zr film formation chamber 13 for performing a zirconium (Zr) film formation process. The Ar plasma processing chamber 12 is, for example, an ICP (Inductively Coupled Plasma) plasma processing device. The semiconductor manufacturing apparatus 10 also includes a Ti film formation chamber 14 for performing a titanium (Ti) film formation process, and a Ru film formation chamber 16 for performing a ruthenium (Ru) film formation process.

[0013] The COR chamber 11, the Ar plasma processing chamber 12, and the Ru film formation chamber 16 are connected to a first transfer module 17, and the Zr film formation chamber 13 and the Ti film formation chamber 14 are connected to a second transfer module 18. The first transfer module 17 is connected to a loader module 20 via a load lock module 19. The arrangement of each processing chamber is not limited to this, and the COR chamber 11, the Ar plasma processing chamber 12, and the Ru film formation chamber 16 may be connected to the second transfer module 18, or the Zr film formation chamber 13 and the Ti film formation chamber 14 may be connected to the first transfer module 17.

[0014] The loader module 20 is provided with a plurality of load ports 21, and a container for accommodating a plurality of wafers, such as a FOUP (not shown), is attached to each load port 21. In addition, the first transfer module 17 and the second transfer module 18 are connected via a wafer transfer unit 22.

[0015] In the semiconductor manufacturing equipment 10, the loader module 20, the first transfer module 17, and the second transfer module 18 each have a built-in transfer robot (not shown). Each transfer robot transfers wafers among the COR chamber 11, the Ar plasma processing chamber 12, the Zr film formation chamber 13, the Ti film formation chamber 14, the Ru film formation chamber 16, and each load port 21.

[0016] The loader module 20 is an atmospheric transfer system or a nitrogen transfer system, and its interior is maintained at atmospheric pressure. The first transfer module 17 and the second transfer module 18 are vacuum transfer systems, and their interiors are depressurized to an almost vacuum. The load lock module 19 is configured so that its interior can be switched between atmospheric pressure and almost a vacuum. When a wafer is transferred between the first transfer module 17 and the loader module 20, the load lock module 19 switches its internal pressure. This allows the wafer to be transferred without changing the internal pressure of the first transfer module 17 or the loader module 20.

[0017] The COR chamber 11, the Ar plasma processing chamber 12, the Ru film formation chamber 16, and the wafer transfer section 22 are connected to a first transfer module 17 via a gate valve 23. In addition, the Zr film formation chamber 13, the Ti film formation chamber 14, and the wafer transfer section 22 are connected to a second transfer module 18 via a gate valve 24. It is noted that the semiconductor manufacturing equipment 10 does not necessarily have to include the COR chamber 11 or the Ru film formation chamber 16.

[0018] In the semiconductor manufacturing equipment 10, a silicon-based wafer transferred from a load port 21 is first transferred to a COR chamber 11. In the COR chamber 11, a natural oxide film formed on the surface of the silicon (Si) or silicon germanium (SiGe) constituting the wafer is removed by COR processing (chemical etching). Next, the wafer is transferred to an Ar plasma processing chamber 12, where an Ar plasma processing is performed on the wafer. Thereafter, the wafer is transferred to a Zr film forming chamber 13, where a Zr film is formed in a pattern opened in the insulating film of the wafer, for example, inside trenches and contact holes (including via holes), by a Zr film forming process.

[0019] Next, the wafer is transferred to the Ti film formation chamber 14, where a Ti film is formed on the Zr film inside the pattern by a Ti film formation process, and then the wafer is transferred to the Ru film formation chamber 16, where Ru, a metal for wiring, is embedded inside the pattern by a Ru film formation process. The Ru film formation process may be performed after nitriding the surface of the Ti film. In this case, the Ti film formation chamber 14 may perform the nitriding process of the Ti film, or a separate process chamber may be prepared to perform the nitriding process and the nitriding process of the Ti film may be promoted in that process chamber.

[0020] FIG. 2 is a schematic cross-sectional view showing the configuration of the Zr film formation chamber 13 in FIG. 2. In the Zr film formation chamber 13, a Zr film formation process is performed on the wafer W by plasma CVD. In FIG. 2, the Zr film formation chamber 13 has a substantially cylindrical processing vessel 25 in which the inside is depressurized and the wafer W (substrate) is accommodated. A mounting table 26 for mounting the wafer W is disposed at the bottom inside the processing vessel 25, and the mounting table 26 is configured to be movable in the vertical direction by a drive mechanism (not shown). In addition, a shower head 27 made of metal, for example, aluminum, is disposed on the ceiling of the processing vessel 25. A processing space U is formed between the mounting table 26 and the shower head 27, and in the processing space U, zirconium chloride (IV) (ZrCl4) gas is converted into zirconium chloride (ZrCl x ) Plasma is generated.

[0021] Furthermore, a wall-shaped liner 28 is disposed inside the processing vessel 25 so as to surround the sides of the processing space U, and a substantially annular baffle ring 29 configured to surround the mounting table 26 is disposed between the liner 28 and the mounting table 26. The liner 28 and the baffle ring 29 suppress the plasma generated in the processing space U from diffusing outside the processing space U. Note that the baffle ring 29 has a large number of through holes (not shown) that communicate the processing space U with the space below the mounting table 26.

[0022] The surfaces of components (hereinafter, "exposed components") at least partially exposed to the processing space U, such as the mounting table 26, the shower head 27, the liner 28, and the baffle ring 29, are covered with an underlayer made of an oxygen-free material. An example of the oxygen-free material is aluminum nitride (AlN). The underlayer prevents oxidation of the base material of the exposed components and prevents corrosion due to chlorine (Cl2) gas, which will be described later. In addition, since the underlayer does not contain oxygen, even if the underlayer is etched by plasma, it does not release oxygen and can suppress oxidation of the Zr film.

[0023] The underlayer is covered with a sacrificial film made of, for example, Zr, the same or similar component as a by-product generated when a Zr film is formed using the plasma in the processing space U. Furthermore, a heater 30 is embedded in the mounting table 26 and the liner 28.

[0024] The Zr film forming chamber 13 includes an oxygen concentration monitor (not shown) for monitoring the oxygen concentration in the processing space U, a plasma monitor (not shown) for monitoring the state of plasma in the processing space U, and a purge gas supply system for supplying a purge gas to the inside of the processing vessel 25. The purge gas supply system includes two annular gas discharge pipes 31a, a purge gas supply source 31b, and a pipe 31c for connecting each gas discharge pipe 31a and the purge gas supply source 31b. Each gas discharge pipe 31a is disposed in the space between the sidewall of the processing vessel 25 and the liner 28, and by discharging purge gas from each point, decomposition products of ZrCl4 gas are prevented from entering the space. This prevents by-products from adhering to the outer sidewall of the liner 28 and the sidewall of the processing vessel 25.

[0025] Further, a sidewall of the processing vessel 25 is provided with a load / unload port 32 for loading / unloading the wafer W into / from the processing space U, and a gate valve 24 for opening / closing the load / unload port 32, and an exhaust system 33 is disposed at the bottom of the processing vessel 25. The exhaust system 33 includes a pump, such as a turbo molecular pump or a dry pump (not shown), for exhausting the inside of the processing vessel 25, and an exhaust valve, such as an APC (Auto Pressure Controller) valve (not shown), for controlling the pressure inside the processing vessel 25. When generating plasma in the processing space U, the exhaust system 33 reduces the pressure in the processing space U to, for example, several tens of mTorr.

[0026] The shower head 27 has a substantially disk-shaped reducing gas inlet 34 and a substantially annular raw material gas inlet 35. The raw material gas inlet 35 is disposed so as to surround the reducing gas inlet 34, and an insulating member 36 is disposed between the raw material gas inlet 35 and the reducing gas inlet 34.

[0027] The reducing gas inlet 34 has a gas diffusion chamber 34a formed therein and a number of gas holes 34b that communicate between the gas diffusion chamber 34a and the processing space U. The raw material gas inlet 35 also has a gas diffusion chamber 35a formed therein and a number of gas holes 35b that communicate between the gas diffusion chamber 35a and the processing space U. The reducing gas inlet 34 faces the wafer W placed on the mounting table 26, but the raw material gas inlet 35 is disposed to surround the reducing gas inlet 34 and does not face the wafer W placed on the mounting table 26.

[0028] A reducing gas supply source 38 is connected to the reducing gas introduction section 34 via a pipe 37, and the reducing gas supply source 38 supplies hydrogen (H2) gas as a reducing gas to the gas diffusion chamber 34a. The H2 gas supplied to the gas diffusion chamber 34a is introduced into the processing space U through each gas hole 34b. The pipe 37 branches into two systems between the reducing gas introduction section 34 and the reducing gas supply source 38, and a filter tank 39 is disposed in one system. A valve 40 is disposed between the filter tank 39 and the reducing gas introduction section 34. The filter tank 39 stores the reducing gas supplied from the reducing gas supply source 38, and when the valve 40 is opened, the stored reducing gas is supplied to the gas diffusion chamber 34a in a short time.

[0029] A raw material gas supply source 42 is connected to the raw material gas inlet 35 via a pipe 41, and the raw material gas supply source 42 supplies ZrCl4 gas as a raw material gas to the gas diffusion chamber 35a. The ZrCl4 gas supplied to the gas diffusion chamber 35a is introduced into the processing space U via each gas hole 35b.

[0030] A cleaning gas supply source 43 is connected to the pipes 37 and 41. The cleaning gas supply source 43 supplies Cl2 gas as a cleaning gas to the gas diffusion chambers 34a and 35a. The cleaning gas supplied to the gas diffusion chambers 34a and 35a is introduced into the processing space U through the gas holes 34b and 35b.

[0031] As described above, the source gas inlet 35 and the reducing gas inlet 34 of the shower head 27 are made of, for example, aluminum, and the source gas inlet 35 is grounded, while the reducing gas inlet 34 is connected to a high-frequency power source 44. Therefore, in this embodiment, the reducing gas inlet 34 functions as an upper electrode. In addition, a matching box 45 such as a POP (Plasma Optimizer) is connected to the mounting table 26. The high-frequency power source 44 generates an electric field in the processing space U by supplying high-frequency power for generating plasma of, for example, 450 kHz to the reducing gas inlet 34. The matching box 45 changes the potential of the mounting table 26 to maintain the electric field generated in the processing space U. The electric field generated in the processing space U excites and decomposes the H2 gas and ZrCl4 gas introduced into the processing space U to generate hydrogen (H) plasma and ZrCl x In the film formation process, the generated ZrCl x The plasma is ZrCl x The precursor reaches the surface of the wafer W, and the ZrCl x The precursor is reduced by H plasma to form a Zr film.

[0032] Furthermore, a control unit (not shown) is provided in the Zr film formation chamber 13. The control unit is made up of a computer having at least a CPU and a memory, and a recipe (program) for executing the film formation process is recorded in the memory.

[0033] Fig. 3 is an enlarged partial cross-sectional view of the vicinity of a pattern on a wafer in which a wiring material is embedded in the semiconductor manufacturing apparatus 10 of Fig. 1. In Fig. 3, the wafer W has a base 46 made of Si or SiGe, and an insulating film 47 made of, for example, silicon nitride (SiN) is formed on the base 46. A contact hole or trench is opened as a pattern 48 in the insulating film 47, and the base 46 is exposed at the bottom of the pattern 48.

[0034] The bottom and sidewalls of the pattern 48 and the top surface of the insulating film 47 are covered with a Zr film 49, the surface of the Zr film 49 is covered with a Ti film 50, and the inside of the pattern 48 is filled with Ru52, which is a metal for wiring. At this time, the surface of the Ti film 50 may be changed to titanium nitride (TiN) by nitriding to form a barrier layer. The barrier layer suppresses the penetration and diffusion of metal molecules of Ru52 into the insulating film 47. A part of the Zr film 49 may also be changed to zirconium nitride (ZrN) to form a thin barrier layer, and this barrier layer also suppresses the penetration and diffusion of metal molecules of Ru52 into the insulating film 47.

[0035] Furthermore, the Zr film 49 and the Ti film 50 are in contact with the Si or SiGe of the base 46 at the bottom of the pattern 48 and are silicided. As a result, a Zr silicide film 49a and a Ti silicide film 50a, which are metal silicides, are formed. The Zr silicide film 49a and the Ti silicide film 50a function as contact materials between the base 46 and the Ru 52.

[0036] However, as described above, it has been confirmed that when the formation of the Zr silicide film 49a progresses to a certain extent, the growth of the Zr silicide film 49a becomes saturated. The reason why the growth of the Zr silicide film 49a becomes saturated is considered to be that the Zr film 49 is difficult to silicidize and that the Zr film 49 is difficult to grow.

[0037] 4 is a diagram for explaining the reason why the Zr film 49 is difficult to silicide. In the figure, an "o" indicates a Si atom, a hatched "o" indicates a Zr atom, and a line protruding from an "o" indicates a bond.

[0038] First, Si is exposed at the base 46 of the wafer W before the Zr film 49 is formed, but the surface of the wafer W is usually highly crystalline, and each Si atom is strongly bonded to each other with very few dangling bonds (FIG. 4(A)). Therefore, there are few mobile Si atoms, and even if the Zr film 49 is formed on the Si of the base 46, there are few Si atoms that are sucked up into the Zr film 49. As a result, Zr silicide (ZrSi) is unlikely to be generated in the Zr film 49 (FIG. 4(B)).

[0039] Thereafter, as the formation of the Zr film 49 progresses, Zr silicide is gradually produced in the base 46 by a small amount of Si atoms sucked up into the Zr film 49, and a Zr silicide film 49a is formed. However, the Zr atoms and Si atoms in the Zr silicide are also strongly bonded to each other with very few dangling bonds (FIG. 4(C)). Therefore, even if a new Zr film 49 is formed on the Zr silicide film 49a by the Zr film formation process, the number of Si atoms sucked up into the Zr film 49 is still small, and Zr silicide is unlikely to be produced in the new Zr film 49 (FIG. 4(D)).

[0040] In this way, since the bonds between Si atoms and between Zr atoms and Si atoms are strong, the number of Si atoms that are absorbed into the Zr film 49 is small, and the Zr film 49 is unlikely to be silicided.

[0041] 5 is a diagram for explaining the reason why the Zr film 49 is difficult to grow. First, a general mechanism for forming the Zr film 49 will be described. For example, ZrCl is generated from ZrCl4 gas introduced into the processing space U. x The plasma is ZrCl x The precursor is attached to the surface of the wafer W. Then, H plasma generated from H gas introduced into the processing space U is used to remove ZrCl x The chlorine (Cl) atoms of the precursor combine with the chlorine (Cl) atoms to generate hydrogen chloride (HCl) (reduction). This HCl becomes a gas molecule and separates from the Zr atoms, so that ZrCl x Only the Zr atoms of the precursor remain, and the remaining Zr atoms form the Zr film 49 .

[0042] By the way, at the stage where the Zr silicide film 49a is hardly formed, the ZrCl generated in the processing space U of the Zr film forming chamber 13 x The plasma is ZrCl x The precursor is attached to the Si on the surface of the base 46. At this time, ZrCl x The Zr atom of the precursor and the Si atom of the base 46 bond together (FIG. 5(A)). Since the bond between the Zr atom and the Si atom is strong, it affects the bond between the adjacent Zr atom and the Cl atom, and the bond between the Zr atom and the Cl atom also becomes strong, and the energy required for the Cl atom to separate (reduction energy of the Cl atom) becomes high. Therefore, ZrCl x Even if the H plasma approaches the precursor, it is difficult for the H plasma to bond with Cl atoms, and it is difficult for the H plasma to generate HCl (FIG. 5(B)). As a result, a lot of ZrCl x The precursor continues to exist, and the Zr film 49 is difficult to form.

[0043] Thereafter, as the Zr film 49 grows little by little, Si atoms are absorbed into the Zr film 49 at the base 46, forming a Zr silicide film 49a. x The plasma is ZrCl x The precursor is attached to the surface of the Zr silicide film 49a, and ZrCl x The Zr atom of the precursor and the Si atom of the Zr silicide film 49a are bonded (FIG. 5(C)). As described above, since the bond between the Zr atom and the Si atom is strong, the bond between the adjacent Zr atom and the Cl atom is also strong, and the reduction energy of the Cl atom becomes high. Therefore, ZrCl x Even if the H plasma approaches the precursor, it is difficult for the H plasma to bond with Cl atoms, and it is difficult for the H plasma to generate HCl (FIG. 5(D)). As a result, a lot of ZrCl x The precursor continues to exist, and the Zr film 49 is difficult to form.

[0044] In this way, the strong bond between Zr atoms and Si atoms increases the reduction energy of Cl atoms, making it difficult for H plasma to generate HCl and making it difficult for only Zr atoms to remain. As a result, it becomes difficult for the Zr film 49 to grow.

[0045] In response to this, in the present embodiment, the surface of the base portion 46 of the wafer W and the surface of the Zr silicide film 49a are activated by Ar plasma, thereby promoting the growth of the Zr silicide film 49a.

[0046] 6 is a diagram for explaining the reason why the Zr film 49 is easily silicided by activation with Ar plasma. As in FIG. 6, in the diagram, "circle" indicates a Si atom, the hatched "circle" indicates a Zr atom, and the line protruding from the "circle" indicates a bond.

[0047] First, when the base 46 of the wafer W before the formation of the Zr film 49 is exposed to Ar plasma, the bonds of each Si atom of the Si or SiGe of the base 46 of the wafer W are broken by the impact input of ions in the Ar plasma, and many Si atoms with dangling bonds are generated (FIG. 6(A)). Since the Si atoms with dangling bonds are easily mobile, when the Zr film 49 is formed on the Si of the base 46, many Si atoms are sucked up into the Zr film 49 (FIG. 6(B)). As a result, Zr silicide is easily generated in the Zr film 49.

[0048] Thereafter, as the formation of the Zr film 49 progresses, many Si atoms are sucked up into the Zr film 49 at the base 46, causing Zr silicide, and a Zr silicide film 49a grows. When the Zr silicide film 49a is exposed to Ar plasma, the bonds between the Zr atoms and the Si atoms in the Zr silicide are broken by the impact input of ions in the Ar plasma, and many Si atoms having dangling bonds are also generated (FIG. 6(C)). After that, when a new Zr film 49 is formed on the Zr silicide film 49a by a Zr film formation process, many Si atoms having dangling bonds are sucked up into the Zr film 49 (FIG. 6(D)). As a result, Zr silicide is more likely to be generated in the Zr film 49.

[0049] In this way, the bonds between the Si atoms and between the Zr atoms and the Si atoms are broken by the impact input of the ions in the Ar plasma, generating many Si atoms that are easily mobile, and many Si atoms are sucked up into the Zr film 49, making the Zr film 49 more easily silicided.

[0050] FIG. 7 is a diagram for explaining the reason why activation by Ar plasma makes it easier for the Zr film 49 to grow.

[0051] First, at a stage where the Zr silicide film 49a is hardly formed, ZrCl x The base 46 of the wafer W to which the precursor is attached is exposed to Ar plasma (FIG. 7A). At this time, ZrCl x The bond between the Zr atom of the precursor and the Si atom of the base 46 is broken (FIG. 7(B)). Then, ZrCl x The bond between the Zr atom and the Cl atom adjacent to the bond between the Zr atom of the precursor and the Si atom of the base 46 is ZrCl x There is no effect from the bond between the Zr atom of the precursor and the Si atom of the base 46. This weakens the bond between the Zr atom and the Cl atom, lowering the reduction energy of the Cl atom.

[0052] And ZrCl x When the H plasma approaches the precursor, the H plasma easily bonds with Cl atoms, generating HCl, which becomes a gas molecule and separates from the Zr atoms (FIG. 7(C)). As a result, ZrCl x Since only the Zr atoms of the precursor remain, the Zr film 49 is easily formed.

[0053] Thereafter, as the Zr film 49 grows, Si atoms are absorbed by the Zr film 49 at the base 46, and the Zr silicide film 49a also grows. x When the Zr silicide film 49a with the precursor attached thereto is exposed to Ar plasma (FIG. 7(D)), ZrCl xThe bonds between the Zr atoms of the precursor and the Si atoms of the Zr silicide film 49a are broken (FIG. 7(E)). x The bond between a Zr atom and a Cl atom adjacent to the bond between a Zr atom of the precursor and a Si atom of the Zr silicide film 49a is ZrCl x The Zr atoms of the precursor are no longer affected by the bonds between the Zr atoms and the Si atoms of the Zr silicide film 49a. At this time, the bonds between the Zr atoms and the Cl atoms are also weakened, and the reduction energy of the Cl atoms is reduced.

[0054] And ZrCl x When the H plasma approaches the precursor, the H plasma easily generates HCl, which becomes gas molecules and separates from the Zr atoms (FIG. 7(F)). At this time, ZrCl x Since only the Zr atoms of the precursor remain, the Zr film 49 is easily formed.

[0055] Thus, ZrCl was formed by the impact of ions in the Ar plasma. x The bond between the Zr atom and the Si atom of the precursor is cut, and the reduction energy of the Cl atom in the bond between the adjacent Zr atom and the Cl atom is lowered. As a result, the reduction of the Cl atom by the H plasma progresses, and the Zr film 49 made of the remaining Zr atoms becomes easier to grow.

[0056] As described above, in this embodiment, the bonds between Si atoms and between Zr atoms and Si atoms are broken (activated) by the impact input of ions in the Ar plasma, thereby promoting the growth of the Zr film 49 and the silicidation of the Zr film 49. This prevents the growth of the Zr silicide film from becoming saturated, and allows the Zr silicide film to grow to a desired thickness.

[0057] The applicant also confirmed the difference in the growth degree of the Zr silicide film 49a depending on whether or not the surface of the base 46 of the wafer W and the surface of the Zr silicide film 49a were activated by Ar plasma. Specifically, when performing a Zr film formation process on the wafer W, the Zr film formation process was performed on the wafer W under the same process conditions except for the presence or absence of activation by Ar plasma, and the thickness of the Zr silicide film 49a formed on the base 46 was confirmed. The thickness of the Zr silicide film 49a formed without activation by Ar plasma was 2.4 nm. The thickness of the Zr silicide film 49a formed with activation by Ar plasma was 7.7 nm.

[0058] When the Zr silicide film 49a having a thickness of 7.7 nm was obtained by activation with Ar plasma, the applicant heated the wafer W placed on the mounting table 26 by the heater 30 during the formation of the Zr film 49. However, the applicant did not subject the wafer W to a heat treatment for silicidating the Zr film 49 after the formation of the Zr film 49. In other words, it was confirmed that if the surface on which the Zr film 49 is to be formed is activated with Ar plasma, a large number of Si atoms having dangling bonds are generated, and therefore silicidation is promoted without the need for a heat treatment.

[0059] Furthermore, the applicant confirmed through experiments the degree of growth of the Zr silicide film 49a when activation was performed using Ar plasma and the temperature of the wafer W (actually, the temperature of the mounting table 26) was maintained in the range of 300° C. to 500° C. during the formation of the Zr film 49. As a result, it was confirmed that saturation of the growth of the Zr silicide film 49a can be avoided by maintaining the temperature of the wafer W in the range of 300° C. to 500° C. during the formation of the Zr film 49, even if no heat treatment for silicidating the Zr film 49 is performed.

[0060] 8 is a flow chart showing a method for forming Zr silicide according to the present embodiment. In this method, in the semiconductor manufacturing apparatus 10, first, the wafer W is transferred to the Ar plasma processing chamber 12 (activation section) and the wafer W is subjected to Ar plasma processing (step S81) (activation step). At this time, the bonds of each Si atom in the base 46 of the wafer W are broken (activated) by impact input of ions in the Ar plasma, and a large number of Si atoms having dangling bonds are generated. In addition, the natural oxide film formed on the surface of the Si or SiGe of the base 46 of the wafer W is also removed by the Ar plasma.

[0061] In the Ar plasma processing in step S81, the flow rate of the Ar gas flowing into the inside of the processing vessel of the Ar plasma processing chamber 12 is set to, for example, 20 sccm. Moreover, a high frequency power for plasma generation is continuously applied to the upper electrode of the Ar plasma processing chamber 12 at, for example, 1000 W, and a high frequency power for bias is continuously applied to the lower electrode of the Ar plasma processing chamber 12 on which the wafer W is placed at, for example, 600 W. The application of this high frequency power for bias draws the Ar plasma into the wafer W, and the collision of ions in the Ar plasma applies an impact to the surface of the base 46 of the wafer W. Note that the high frequency power for bias may be applied in a pulsed manner in order to prevent excessive damage from being given to the sidewalls of the pattern 48 of the wafer W by the impact input of ions in the Ar plasma.

[0062] In addition, the duration of the Ar plasma processing is set to, for example, 18 seconds, the pressure inside the processing vessel is set to, for example, 5 mTorr, and the temperature of the mounting table serving as the lower electrode on which the wafer W is placed is set to, for example, 20°C.

[0063] Next, the wafer W is transferred to the Zr film formation chamber 13 (silicide formation section), and a Zr film formation process is performed on the wafer W (step S82) (metal film formation step). At this time, a Zr film 49 is formed inside the pattern 48 of the wafer W, and at the base 46 at the bottom of the pattern 48, Si atoms having dangling bonds are sucked up by the formed Zr film 49, forming a Zr silicide film 49a.

[0064] In the Zr film formation process in step S82, H2 gas and ZrCl4 gas are continuously supplied into the processing vessel 25, or H2 gas is continuously supplied while ZrCl4 gas is supplied in a pulsed manner. In addition, the high frequency power supply 44 applies high frequency power for plasma generation to the reducing gas inlet 34 continuously or in a pulsed manner.

[0065] After step S82 is performed, the method ends, but the wafer W is transferred directly to the Ti film formation chamber 14, where a Ti film 50 is formed inside the pattern 48. Furthermore, the wafer W is transferred to the Ru film formation chamber 16, where Ru 52 is embedded inside the pattern 48.

[0066] 9 is a flow chart showing a first modified example of the Zr silicide forming method according to the present embodiment. In this method, in the semiconductor manufacturing apparatus 10, first, the wafer W is transferred to the Ar plasma processing chamber 12, and the wafer W is subjected to Ar plasma processing (step S91). At this time, the base 46 of the wafer W is activated by impact input of ions in the Ar plasma, and the natural oxide film formed on the surface of the Si or SiGe of the base 46 of the wafer W is also removed by the Ar plasma. The Ar plasma processing conditions in step S91 are the same as those in step S81.

[0067] Next, the wafer W is transferred to the Zr film formation chamber 13, and a Zr film formation process is performed on the wafer W (step S92). At this time, at the base 46 at the bottom of the pattern 48, Si atoms having dangling bonds are sucked up from the base 46 to the formed Zr film 49, forming a Zr silicide film 49a. The Zr film formation process conditions in step S92 are the same as those in step S91.

[0068] Next, the wafer W is transferred back to the Ar plasma processing chamber 12, and the wafer W is subjected to Ar plasma processing (step S93). At this time, the Zr silicide film 49a is activated by impact input of ions in the Ar plasma, and a large number of Si atoms having dangling bonds are generated. In addition, ZrCl attached to the base 46 of the wafer W and the Zr silicide film 49a is removed. x The bond between the Zr atom and the Si atom of the precursor is broken (activated), and the reduction energy of the Cl atom in the bond between the adjacent Zr atom and the Cl atom becomes lower.

[0069] The conditions for the Ar plasma treatment in step S93 are the same as those for the Ar plasma treatment in step S91, except for the duration. Since it is not necessary to remove the native oxide film, the duration of the Ar plasma treatment in step S93 is set to be shorter than that of the Ar plasma treatment in step S91, for example, 1 to 10 seconds.

[0070] Next, the wafer W is transported again to the Zr film formation chamber 13, and the wafer W is subjected to a Zr film formation process (step S94). At this time, at the base 46 at the bottom of the pattern 48, Si atoms having dangling bonds are sucked up from the Zr silicide film 49a to form the Zr silicide film 49a in the formed Zr film 49. The Zr film formation process conditions in step S94 are the same as those in step S92.

[0071] Thereafter, it is determined whether step S93 and step S94 have been performed a specified number of times (step S95). If step S93 and step S94 have not been performed the specified number of times, the process returns to step S93, and steps S93 and S94 are performed. As a result, steps S93 and S94 are repeatedly performed. On the other hand, if steps S93 and S94 have been performed the specified number of times, the method is terminated. The specified number of times is set by confirming in advance by experiment or the like how many times steps S93 and S94 are performed, which are necessary for the Zr silicide film 49a to grow to a desired film thickness.

[0072] The Zr film forming chamber 13 may include a means for estimating or observing the thickness of the Zr silicide film 49a, and the estimating or observing means may estimate or observe the thickness of the Zr silicide film 49a. In this case, in step S95, it is determined whether the estimated or observed thickness of the Zr silicide film 49a has reached a desired thickness. If the thickness of the Zr silicide film 49a has not reached the desired thickness, steps S93 and S94 are repeated, and if the thickness of the Zr silicide film 49a has reached the desired thickness, the method is terminated.

[0073] After this method is completed, the wafer W is transferred directly to the Ti film formation chamber 14 where a Ti film 50 is formed inside the pattern 48, and the wafer W is then transferred to the Ru film formation chamber 16 where the pattern 48 is filled with Ru 52.

[0074] 10 is a flow chart showing a second modified example of the Zr silicide forming method according to the present embodiment. In this method, in the semiconductor manufacturing apparatus 10, first, the wafer W is transferred to the COR chamber 11 and subjected to the COR process. At this time, a native oxide film formed on the surface of the Si or SiGe base 46 of the wafer W is removed (step S101).

[0075] Next, the wafer W is transferred to the Ar plasma processing chamber 12, and the wafer W is subjected to Ar plasma processing (step S102). At this time, the base 46 of the wafer W is activated by impact input of ions in the Ar plasma. Since it is not necessary to remove the native oxide film, the duration of the Ar plasma processing in step S102 is set to be shorter than the duration of the Ar plasma processing in step S81, for example, 1 to 10 seconds.

[0076] Next, the wafer W is transferred to the Zr film formation chamber 13, and a Zr film formation process is performed on the wafer W (step S103). At this time, at the base 46 at the bottom of the pattern 48, Si atoms having dangling bonds are sucked up from the base 46 to the formed Zr film 49, forming a Zr silicide film 49a. The Zr film formation process conditions in step S103 are the same as those in step S91.

[0077] Thereafter, it is determined whether or not steps S102 and S103 have been executed a prescribed number of times (step S104). If steps S102 and S103 have not been executed the prescribed number of times, the process returns to step S102, and steps S102 and S103 are executed. Thus, steps S102 and S103 are executed repeatedly.

[0078] In step S102 from the second time onward, the Zr silicide film 49a is activated by the impact of ions in the Ar plasma, and further, the ZrCl 2 attached to the Zr silicide film 49a is removed. x The bonds between the Zr and Si atoms of the precursor are cut off. In step S103 from the second time onwards, Si atoms having dangling bonds are sucked up from the Zr silicide film 49a into the formed Zr film 49, forming the Zr silicide film 49a. On the other hand, if steps S102 and S103 have been performed the specified number of times, the method is terminated.

[0079] Also, in step S104, it may be determined whether the estimated or observed thickness of the Zr silicide film 49a has reached the desired thickness. In this case, if the thickness of the Zr silicide film 49a has not reached the desired thickness, steps S102 and S103 are repeated, and if the thickness of the Zr silicide film 49a has reached the desired thickness, the method is terminated.

[0080] After this method is completed, the wafer W is transferred directly to the Ti film formation chamber 14 where a Ti film 50 is formed inside the pattern 48, and the wafer W is then transferred to the Ru film formation chamber 16 where the pattern 48 is filled with Ru 52.

[0081] 11 is a flow chart showing a third modified example of the Zr silicide forming method according to the present embodiment. In this method, similarly to the second modified example, in the semiconductor manufacturing apparatus 10, first, the wafer W is transferred to the COR chamber 11, and the wafer W is subjected to COR processing to remove a native oxide film formed on the surface of the Si or SiGe base 46 of the wafer W (step S111).

[0082] Next, the wafer W is transferred to the Zr film formation chamber 13, and a Zr film formation process is performed on the wafer W (step S112). At this time, a Zr film 49 is formed on the base 46 at the bottom of the pattern 48. However, since the base 46 is not activated, almost no Si atoms having dangling bonds are absorbed by the formed Zr film 49, and the Zr film 49 is hardly silicided.

[0083] Next, the wafer W is transferred to the Ar plasma processing chamber 12, and the wafer W is subjected to Ar plasma processing (step S113). At this time, the base 46 of the wafer W is activated via the Zr film 49 by impact input of ions in the Ar plasma. Since it is not necessary to remove the native oxide film, the duration of the Ar plasma processing in step S113 is set to be shorter than the duration of the Ar plasma processing in step S81, for example, 1 to 10 seconds.

[0084] Next, the wafer W is transported again to the Zr film formation chamber 13, and a Zr film formation process is performed on the wafer W (step S114). At this time, at the base 46 at the bottom of the pattern 48, Si atoms having dangling bonds are sucked up from the base 46 to the formed Zr film 49, forming a Zr silicide film 49a. The Zr film formation process conditions in step S114 are the same as those in step S91.

[0085] Thereafter, it is determined whether or not steps S113 and S114 have been executed a prescribed number of times (step S115). If steps S113 and S114 have not been executed the prescribed number of times, the process returns to step S113, and steps S113 and S114 are executed. Thus, steps S113 and S114 are executed repeatedly.

[0086] In step S113 from the second time onward, the Zr silicide film 49a is activated by the impact of ions in the Ar plasma, and further, the ZrCl 2 attached to the Zr silicide film 49a is removed. x The bonds between the Zr and Si atoms of the precursor are cut off. In step S114 from the second time onwards, Si atoms having dangling bonds are sucked up from the Zr silicide film 49a into the formed Zr film 49, forming the Zr silicide film 49a. On the other hand, if steps S113 and S114 have been performed the specified number of times, the method is terminated.

[0087] Also in step S115, it may be determined whether the estimated or observed thickness of the Zr silicide film 49a has reached the desired thickness. In this case, too, if the thickness of the Zr silicide film 49a has not reached the desired thickness, steps S113 and S114 are repeated, and if the thickness of the Zr silicide film 49a has reached the desired thickness, the method is terminated.

[0088] After this method is completed, the wafer W is transferred directly to the Ti film formation chamber 14 where a Ti film 50 is formed inside the pattern 48, and the wafer W is then transferred to the Ru film formation chamber 16 where the pattern 48 is filled with Ru 52.

[0089] As described above, according to this embodiment, the bonds between Si atoms and between Zr atoms and Si atoms are broken (activated) by the impact input of ions in the Ar plasma, thereby promoting the growth of the Zr film 49 and the silicidation of the Zr film 49. This prevents the growth of the Zr silicide film from becoming saturated, and allows the Zr silicide film to grow to a desired film thickness. The effect of growing the Zr silicide film to a desired film thickness in this embodiment can be obtained not only when the base 46 of the wafer W is made of Si, but also when the base 46 of the wafer W is made of SiGe.

[0090] Furthermore, in this embodiment, a large number of Si atoms having dangling bonds are generated by the impact input of ions in the Ar plasma, so that the silicidation of the Zr film 49 can be promoted without carrying out a heat treatment.

[0091] Furthermore, in this embodiment, in the semiconductor manufacturing apparatus 10, the Ar plasma processing chamber 12 and the Zr film formation chamber 13 are connected to the first transfer module 17 and the second transfer module 18, which are vacuum transfer systems. Therefore, the Ar plasma processing, the Zr film formation process, and the formation of the Zr silicide film 49a accompanying the Zr film formation process can be performed in-situ in the same vacuum system. This can improve the throughput.

[0092] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the present disclosure.

[0093] For example, in the semiconductor manufacturing apparatus 10, the Ar plasma process and the Zr film formation process are performed in the Ar plasma process chamber 12 and the Zr film formation chamber 13, respectively. However, for example, by providing the Ar plasma process chamber 12 with a source gas supply source 42 for supplying ZrCl4 gas and a reducing gas supply source 38 for supplying H2 gas, not only the Ar plasma process but also the Zr film formation process may be performed in the Ar plasma process chamber 12. This can further improve the throughput.

[0094] Furthermore, the Ar plasma processing chamber 12 is not limited to an ICP plasma processing apparatus, and may be another plasma processing apparatus capable of applying an impact input by ions in Ar plasma, such as a CCP (Capacitive Coupled Plasma) plasma processing apparatus.

[0095] Furthermore, in this embodiment, the impact input of ions in the Ar plasma is used to break the bonds between each Si atom and the bonds between Zr atoms and Si atoms, but the impact input of ions in a rare gas plasma other than Ar plasma may also be used.

[0096] In this embodiment, the native oxide film is also removed by the Ar plasma treatment. In this case, H2 gas may be added to the Ar plasma treatment to promote the reduction of the native oxide film and ensure the removal of the native oxide film. [Explanation of symbols]

[0097] W wafer 10. Semiconductor manufacturing equipment 11 COR room 12 Ar plasma treatment chamber 13 Zr film formation chamber 46 Base 49 Zr film 49a Zr silicide film

Claims

1. 1. A method for forming zirconium silicide on a substrate, comprising: an activation step of activating the surface of the substrate on which the zirconium film is to be formed by argon plasma; and forming a metal film on the activated surface to form the zirconium film.

2. 2. The method of claim 1, wherein the surface activated by the argon plasma is composed of silicon or silicon germanium.

3. 2. The method of claim 1, wherein the surface activated by the argon plasma is comprised of zirconium silicide.

4. 2. The method of claim 1, wherein a heat treatment for forming zirconium silicide is not performed after the metal film forming step.

5. 2. The method of claim 1, wherein the temperature of the substrate is maintained in the range of 300° C. to 500° C. in the metal film forming step.

6. 2. The method of claim 1, wherein said activation step and said metal film formation step are repeatedly performed.

7. 2. The method of claim 1, wherein said activation step removes a native oxide film formed on said substrate.

8. 8. The method for forming a silicide according to claim 7, wherein after removing the native oxide film in the activation step, the metal film forming step is performed once, and then the activation step and the metal film forming step are repeatedly performed.

9. 2. The method of claim 1, further comprising the step of removing a native oxide film formed on said substrate by chemical etching prior to said activation step.

10. 10. The method for forming a silicide according to claim 9, wherein after removing the native oxide film by the chemical etching, the activation step and the metal film forming step are repeatedly performed.

11. 10. The method for forming a silicide according to claim 9, wherein after removing the native oxide film by the chemical etching, the metal film forming step is performed once, and then the activation step and the metal film forming step are repeatedly performed.

12. 2. The method for forming a silicide according to claim 1, wherein said activation step comprises applying a high frequency bias power in a pulsed manner for attracting argon ions.

13. 3. The method for forming a silicide according to claim 2, wherein in said activation step, dangling bonds of silicon are formed on the surface activated by said argon plasma.

14. 2. The method of claim 1, wherein in said metal film forming step, said zirconium film is formed by plasma CVD using zirconium (IV) chloride gas and hydrogen gas.

15. a silicide forming section for forming zirconium silicide on the substrate; an activation unit that activates a surface of the substrate on which a zirconium film is to be formed by using argon plasma; The silicide forming section forms the zirconium film on the activated surface.

16. 16. The semiconductor manufacturing apparatus according to claim 15, wherein the silicide forming section and the activation section are connected to a vacuum transfer system.

17. 16. The semiconductor manufacturing apparatus according to claim 15, wherein said activation section also serves as said silicide formation section by carrying out plasma CVD using zirconium (IV) chloride gas and hydrogen gas.

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