Film formation method, semiconductor device manufacturing method, and film formation apparatus

Abstract

To provide a film deposition method capable of depositing a low resistance titanium silicide at low temperature; a method for manufacturing a semiconductor device; and a film deposition apparatus.SOLUTION: A film deposition method capable of depositing a titanium silicide film in the contact formation area of a substrate comprises the steps of: preparing the substrate having the contact formation area; and sequentially supplying TiI4 gas as a Ti precursor and Si containing gas as reducing gas to the substrate to deposit the titanium silicide film on the contact formation area of the substrate by ALD.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a film formation method, a method for manufacturing a semiconductor device, and a film formation apparatus. [Background technology]

[0002] Titanium silicide is used for Si contacts in semiconductor devices. Non-Patent Document 1 describes a method of forming titanium silicide (TiSi2) by sequentially depositing Ti and TiN on a Si substrate and then reacting the Ti with the Si of the substrate by annealing. Patent Document 1 also describes forming a TiSi2 layer on a silicon substrate by atomic layer deposition (ALD) using TiCl4 and SiH4. Non-Patent Document 2 also describes forming a TiSi2 film by chemical vapor deposition (CVD) using TiI4 and SiH4. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-253797 [Non-patent literature]

[0004] [Non-Patent Document 1] K. Yanagihara and S. Hayashi, "Boron Redistribution during Silicidation Process of Titanium-Silicon System", Journal of Surface Analysis Vol. 5 No. 1 (1999) [Non-patent document 2] HwaSung Rhee, "Formation of TiSi2 Thin Films from Chemical Vapor Deposition Using TiI4" Journal of the Korean Physical Society, Vol 33, November 1998, pp. S121 - S124 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a film formation method, a semiconductor device manufacturing method, and a film formation apparatus that are capable of forming a low-resistivity titanium silicide film at a low temperature. [Means for solving the problem]

[0006] A film formation method according to one aspect of the present disclosure is a film formation method for forming a titanium silicide film in a contact formation region of a substrate, the method comprising the steps of: preparing a substrate having an insulating film formed on a base body and a contact formation region, which is a silicon-containing region into which impurities have been diffused, exposed at the bottom of the contact hole; and selectively adsorbing a film formation inhibitor that inhibits the formation of a titanium silicide film in portions of the substrate other than the contact formation region. Keep the substrate temperature below 450°C. TiI4 gas as a Ti precursor, TiI 4 Gas reduction to form silicide and a Si-containing gas as a reducing gas are sequentially supplied to the substrate, without reacting with silicon contained in the contact formation region and forming a titanium silicide film in the contact formation region of the substrate by ALD. [Effects of the Invention]

[0007] According to the present disclosure, a low-resistivity titanium silicide film can be formed at a low temperature. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a flowchart showing a first embodiment of a film forming method. [Figure 2] FIG. 2 is a cross-sectional view showing an example of a substrate. [Figure 3] 3 is a cross-sectional view showing a state in which a TiSix film is formed in a contact formation region at the bottom of a contact hole in the substrate of FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view showing a state in which wiring is formed by filling a wiring material into contact holes in the substrate on which the TiSix film of FIG. 3 is formed. [Figure 5] FIG. 10 is a diagram showing the results of a simulation of the relationship between reaction temperature (°C) and free energy ΔG (kcal) when TiI4, TiBr4, and TiCl4 are used as Ti precursors and SiH4 gas is used as the Si compound. [Figure 6] 10 is a flowchart showing a second embodiment of a film forming method. [Figure 7] 3 is a cross-sectional view showing a state in which a film formation inhibitor is formed on the substrate of FIG. 2. FIG. [Figure 8] 3 is a diagram showing a state in which a film-formation inhibitor is formed on the substrate of FIG. 2, a TiSix film is formed, and then a wiring material is buried in the contact holes. [Figure 9] FIG. 10 is a diagram schematically illustrating a case where a step of forming a film-forming inhibitor is performed prior to a step of forming a TiSix film. [Figure 10] FIG. 10 is a diagram schematically illustrating an example of sequentially supplying a film-forming inhibitor during an ALD cycle in the process of forming a TiSix film. [Figure 11] FIG. 10 is a diagram schematically illustrating an example in which a film-forming inhibitor is supplied simultaneously when one or both of TiI4 gas and Si-containing gas (SiH4 gas) are supplied in the step of forming a TiSix film. [Figure 12] FIG. 2 is a cross-sectional view showing an example of a film forming apparatus used in the film forming method. [Figure 13] FIG. 13 is a diagram showing a TiI4 gas supply source in the film forming apparatus of FIG. [Figure 14] 13 is a diagram showing an example of a gas supply sequence when a TiSix film is formed by the film forming apparatus of FIG. 12. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the accompanying drawings.

[0010] <Background and Overview> First, the background and overview of the film forming method of the present disclosure will be described. In addition, titanium silicide exists as TiSi2 and TiSi, so in the following explanation, titanium silicide will be referred to as TiSi, which includes both of these. x It is written as follows.

[0011] TiSi used for Si contacts x When forming the film, a lower processing temperature is required to reduce the risk of device failure due to the thermal budget, and a temperature of 450°C or less is required for logic semiconductors, which have low heat resistance. Furthermore, with the miniaturization of semiconductor devices, TiSi x There is a demand for films with low resistance.

[0012] Si contacts are formed in impurity diffusion regions such as source and drain electrodes. As mentioned in Non-Patent Document 1, Ti is reacted with Si in the substrate by annealing (reduction reaction) to form TiSi x When forming a film, the reaction (reduction reaction) between Ti and Si also sucks up the impurities added to the Si. The contact resistance is proportional to the resistance of the material and the Schottky barrier, and inversely proportional to the impurity concentration at the metal (Ti)-Si interface. Therefore, the contact resistance increases when the impurity concentration decreases due to the sucking up of impurities from the impurity diffusion region. In addition, Non-Patent Document 1 states that TiSi x The reaction to form the SiO2 requires a high processing temperature of 650°C or higher, making it difficult to apply to logic semiconductors.

[0013] In addition, in Patent Document 1, TiSi is grown on a silicon substrate by ALD using TiCl4 and SiH4. xFurthermore, Non-Patent Document 2 describes the formation of a TiSi2 film by CVD using TiI4 and SiH4, but the substrate temperature during this process is as high as 650°C.

[0014] Therefore, TiSi, which constitutes the Si contact, has been recently required. x The aim of this study was to lower the processing temperature and reduce the resistance of the film. As a result, TiSi was directly deposited on the contact formation area of ​​the substrate by ALD using TiI4 gas and Si-containing gas. x It has been found that forming a film is effective.

[0015] <Film formation method> Next, an embodiment of the film forming method will be described. [First embodiment of film formation method] 1 is a flowchart illustrating a first embodiment of a film formation method. As shown in FIG. 1, the first embodiment of the film formation method includes a step of preparing a substrate having a contact formation region (step ST1), and a step of depositing TiSi in the contact formation region of the substrate by ALD using TiI gas as a Ti precursor and a Si-containing gas as a reducing gas. x and a step of forming a film (step ST2).

[0016] The substrate in step ST1 is configured as shown in FIG. 2. The substrate 101 is, for example, a semiconductor wafer (silicon wafer), and in this example, a 3D device is formed on it. Specifically, the substrate 101 has an insulating film 102 on a base (not shown), and a contact hole 103 is formed in the insulating film 102. A contact formation region 104 is exposed at the bottom of the contact hole 103. The contact formation region 104 is a silicon-containing region in which impurities such as B are diffused, such as a source electrode or a drain electrode, and is made of, for example, Si or SiGe formed by epitaxial growth. In this case, the contact formation region 104 may be epitaxially grown vertically or epitaxially grown horizontally in a sheet shape. An example of the insulating film 102 is a SiN film. It may also be a SiO2 film. Note that, although a 3D device is illustrated in FIG. 2, a general 2D device may also be used, in which case the contact formation region 104 may be a Si substrate.

[0017] In step ST2, TiI gas, which is a Ti precursor, and a Si-containing gas, which is a reducing gas (silicidation gas), are sequentially (typically alternately) supplied to the substrate 101 in the processing chamber. As a result, TiSi as a Si contact is formed on the surface of the contact formation region 104, as shown in FIG. x The film 105 is formed.

[0018] TiSi x After forming the film 105, as shown in FIG. 4, a low-resistance wiring material such as Co, W, Mo, or Ru is filled into the contact hole 103, and a TiSi x Wiring 106 is formed on the film 105. In this way, a desired semiconductor device is obtained.

[0019] Prior to the film formation process in step ST2, a process may be performed to remove a native oxide film formed on the surface of the contact formation region 104. The native oxide film can be removed by a pre-cleaning process using Ar sputtering or the like.

[0020] Furthermore, after step ST2, plasma treatment using H2 plasma or the like may be performed.

[0021] Next, the film forming process in step ST2 will be described in detail. TiSi in step ST2 x In forming the film 105, TiI4 used as a Ti precursor has high reactivity, so it can react with Si compound gas at low temperature, and TiSi x A film can be formed. Figure 5 shows the results of a simulation of the relationship between reaction temperature (°C) and free energy ΔG (kcal) when TiI4, TiBr4, and TiCl4 are used as Ti precursors and SiH4 gas is used as the Si compound. The following reactions (1) to (3) were used in the simulation. In Figure 5, a negative ΔG indicates that the reaction is progressing. TiI4(g)+2SiH4(g)=TiSi2+2I2(g)+4H2(g) ···(1) TiBr4(g)+2SiH4(g)=TiSi2+2Br2(g)+4H2(g) ···(2) TiCl4(g)+2SiH4(g)=TiSi2+2Cl2(g)+4H2(g) ···(3)

[0022] As shown in the simulation results in Figure 5, when TiBr4 and TiCl4 are used as Ti precursors, a high temperature of 1000°C or higher is required for the film formation reaction to occur. In contrast, when TiI4 is used as the Ti precursor, ΔG becomes negative at around 350°C, indicating that film formation is possible at low temperatures of 450°C or lower.

[0023] In this way, TiSi was obtained by ALD using TiI4 gas and a Si-containing gas. xSince the film can be formed at a low temperature of 450°C or less, the risk of device failure due to thermal budget can be reduced even in the case of logic semiconductors. In addition, instead of forming silicide by reaction with the underlying Si, TiSi is directly deposited on the contact formation region 104 by ALD. x Since a film is formed, it is possible to suppress the absorption of impurities such as B from the contact formation region 104, and it is possible to reduce the resistance of the Si contact.

[0024] In addition, ALD has high controllability of film thickness, so TiSi x By forming a film, TiSi x This makes it possible to make the film thinner. TiSi x The thickness of the film can be in the range of 0.5 to 10 nm.

[0025] Examples of the Si-containing gas used as the reducing gas include silane-based gases, iodide-based gases, chloride-based gases, bromide-based gases, and fluoride-based gases, as described below. Silane-based gases: Si2H6, SiH4 Iodide gases: Si2I6, SiI4, SiHI3, SiH2I2, SiH3I Chloride gases: Si2Cl6, SiCl4, SiHCl3, SiH2Cl2, SiH3Cl Bromide gases: Si2Br6, SiBr4, SiHBr3, SiH2Br2, SiH3Br Fluoride gases: Si2F6, SiF4, SiHF3, SiH2F2, SiH3F

[0026] Among these, SiH4 gas is preferable in terms of reactivity. In addition, iodide gases are the same type of gas as TiI4, and therefore have the advantage of being able to reduce impurities.

[0027] In addition to the Si-containing gas, other reducing gases may be used. Examples of the other reducing gas include H2 gas, deuterium-containing gas, and NH3 gas. The deuterium-containing gas refers to deuterium gas, which is a gas of deuterium molecules formed by two deuterium atoms bonded together, or a gas of a molecule formed by one protium atom and one deuterium atom bonded together. By using at least one of H2 gas, deuterium-containing gas, and NH3 gas as the other reducing gas in addition to the Si-containing gas, it is possible to make the reduction reaction proceed more easily. The timing of supplying the other reducing gas is not particularly limited. For example, the other reducing gas may be supplied every time the Si-containing gas is supplied, or may be supplied part of the timing of supplying the Si-containing gas, for example, once every few times. Of course, the other reducing gas may also be supplied at a timing separate from that of SiH4 gas.

[0028] In step ST2, after the TiI gas and the Si-containing gas are supplied, residual gas in the processing chamber is discharged with a purge gas. An inert gas can be used as the purge gas. N2 gas or Ar gas can be preferably used as the inert gas. The purge gas may be continuously supplied during the film formation process.

[0029] The pressure inside the processing chamber during step ST2 may be in the range of 13 to 6650 Pa (0.1 to 50 Torr).

[0030] [Second embodiment of film forming method] 6 is a flowchart showing a second embodiment of the film forming method. As shown in FIG. 6, the second embodiment of the film forming method includes a step of preparing a substrate having a contact formation region (step ST11), and a step of depositing TiSi x a step of forming a film formation inhibitor that inhibits the formation of a film (step ST12); and a step of forming a TiSi film on a contact formation region of the substrate by ALD using TiI gas as a Ti precursor and a Si-containing gas as a reducing gas. x and a step of forming a film (step ST13).

[0031] 2 can be used as the substrate 101 in step ST11, as in step ST1. In step ST13, TiSi x The film 105 is formed.

[0032] The step of forming the film formation inhibitor in step ST12 is performed by forming TiSi on the region other than the contact formation region 104, that is, on the inner surface of the contact hole 103 in the insulating film 102, as shown in FIG. x The film formation inhibitor 107 that inhibits the film formation is adsorbed. x When forming the film 105, the inner surface of the contact hole 103 in the insulating film 102 is also coated with TiSi x A film may be formed on the surface. x Since TiSi has a higher resistance than the wiring material, the inner surface of the contact hole 103 is x If the wiring material is buried with the film still present, the wiring resistance will increase. For this reason, a film formation inhibitor 107 is adsorbed on the inner surface of the contact hole 103, which is a region other than the contact formation region 104, to prevent TiSi x The film formation inhibitor 107 can be formed very thinly by simply adsorbing it. x After the film 105 is formed, even if the wiring 106 is formed, there is almost no increase in the wiring resistance.

[0033] The film formation inhibitor 107 is preferably an organic substance that is easily adsorbed to the insulating film 102, and alkyl halides or alkenes can be suitably used. Alkyl halides and alkenes are particularly easily adsorbed to nitrogen-containing materials such as SiN. Alkyl halides are represented by the general formula RX (R is an alkyl group and X is a halogen atom), and alkenes are hydrocarbons with carbon double bonds (ethylene, propylene, isobutylene, etc.).

[0034] The step of forming the film formation inhibitor in step ST12 is replaced by a step ST13 of forming a TiSi xThis may be performed prior to the step of forming the TiSi film, or as shown in FIGS. 10 and 11, after the step ST13. x The example in Figure 10 shows a TiSi x This is an example in which a film formation inhibitor is supplied sequentially during an ALD cycle when forming a film. The example in FIG. 11 is an example in which a film formation inhibitor is supplied simultaneously when either TiI gas or a Si-containing gas (e.g., SiH gas) is supplied or when both are supplied.

[0035] <Film forming equipment> Next, an example of a film formation apparatus capable of carrying out the above-described embodiment of the film formation method will be described. Fig. 12 is a cross-sectional view showing the example of the film formation apparatus. Here, an example is shown in which SiH gas is used as the Si-containing gas and N gas is used as the inert gas used as a purge gas or the like.

[0036] The film forming apparatus 100 includes a chamber 1 which is a processing vessel, a susceptor (mounting table) 2, a shower head 3, an exhaust unit 4, a gas supply mechanism 5, and a control unit 6.

[0037] The processing vessel, chamber 1, is made of a substantially cylindrical metal. A sidewall of chamber 1 is formed with a loading / unloading port 26 for loading / unloading a substrate W into / from a vacuum transfer chamber (not shown) by a transfer mechanism (not shown). The loading / unloading port 26 can be opened and closed by a gate valve G.

[0038] An annular exhaust duct 28 with a rectangular cross section is provided above the main body of the chamber 1. Slits 28a are formed along the inner peripheral surface of the exhaust duct 28. An exhaust port 28b is also formed in the outer wall of the exhaust duct 28. A top wall 29 is provided on the upper surface of the exhaust duct 28 so as to close the upper opening of the chamber 1. A seal ring 30 provides an airtight seal between the top wall 29 and the exhaust duct 28.

[0039] The susceptor 2, which is a mounting table, is used to mount the substrate W within the chamber 1. An example of the substrate W is a semiconductor wafer (silicon wafer) having the structure shown in FIG. 2 as described above. The susceptor 2 is a circular disk sized to accommodate the wafer W and is installed horizontally. The susceptor 2 is supported by a support member 33. A heater 31 for heating the substrate W is embedded within the susceptor 2. The heater 31 generates heat when power is supplied from a heater power supply (not shown). The output of the heater 31 is controlled to maintain the substrate W at a desired temperature. The susceptor 2 is provided with a ceramic cover member 32 that covers the outer periphery and side surfaces of the wafer mounting surface.

[0040] A support member 33 that supports the susceptor 2 extends from the center of the bottom surface of the susceptor 2 to below the chamber 1, passing through a hole formed in the bottom wall of the chamber 1, and its lower end is connected to an elevation mechanism 34, which enables the susceptor 2 to be raised and lowered via the support member 33 between a processing position shown in Fig. 2 and a transfer position, shown by a two-dot chain line below, where a wafer can be transferred. A flange 35 is attached to the support member 33 below the chamber 1, and a bellows 36 is provided between the bottom surface of the chamber 1 and the flange 35 to separate the atmosphere inside the chamber 1 from the outside air, and expands and contracts as the susceptor 2 is raised and lowered.

[0041] Three wafer support pins 37 (only two shown) are provided near the bottom surface of the chamber 1 so as to protrude upward from a lift plate 37a. The wafer support pins 37 can be raised and lowered via the lift plate 37a by a lift mechanism 38 provided below the chamber 1, and are inserted into through holes 22 provided in the susceptor 2 at the transfer position so as to be able to protrude and retract relative to the upper surface of the susceptor 2. In this way, the substrate W is transferred between a wafer transfer mechanism (not shown) and the susceptor 2.

[0042] A heater (not shown) is embedded inside the wall of the chamber 1, and the temperature of the inner wall of the chamber 1 is controlled to about 100 to 350°C. x It is designed to inhibit film adhesion.

[0043] The showerhead 3 is used to supply processing gas into the chamber 1 in a shower-like manner, and is provided at the top of the chamber 1 so as to face the susceptor 2, with a diameter approximately the same as that of the susceptor 2. The showerhead 3 has a main body 39 fixed to the ceiling wall 29 of the chamber 1, and a shower plate 40 connected below the main body 39. A gas diffusion space 41 is formed between the main body 39 and the shower plate 40.

[0044] A plurality of gas dispersion members 42 are provided within the gas dispersion space 41. A plurality of gas discharge holes are formed around the periphery of the gas dispersion members 42. The gas dispersion members 42 are connected to one end of each of a plurality of gas supply paths 43 provided in the main body 39. The other ends of the gas supply paths 43 are connected to a diffusion section 44 formed in the center of the upper surface of the main body 39. Two gas introduction holes 45a and 45b are provided in the center of the main body 39, penetrating from the upper surface to the diffusion section 44.

[0045] A downwardly protruding annular protrusion 40b is formed on the periphery of the shower plate 40, and gas ejection holes 40a are formed on the flat surface inside the annular protrusion 40b of the shower plate 40. When the susceptor 2 is in the processing position, a processing space S is formed between the shower plate 40 and the susceptor 2, and the annular protrusion 40b and the upper surface of the cover member 32 of the susceptor 2 are close to each other to form an annular gap 48.

[0046] The exhaust unit 4 includes an exhaust pipe 46 connected to the exhaust port 28b of the exhaust duct 28, and an exhaust mechanism 47 having a vacuum pump, a pressure control valve, etc., connected to the exhaust pipe 46. During processing, gas inside the chamber 1 reaches the exhaust duct 28 through the slit 28a, and is exhausted from the exhaust duct 28 through the exhaust pipe 46 by the exhaust mechanism 47 of the exhaust unit 4.

[0047] The process gas supply mechanism 5 includes a TiI gas supply source 51 that supplies TiI gas, which is a Ti precursor, and a SiH gas supply source 52 that supplies SiH gas as a reducing gas (silicidation gas). The process gas supply mechanism 5 further includes a first N gas supply source 53 and a second N gas supply source 54 that supply N gas, which is a purge gas, an R gas supply source 55 that supplies other reducing gases such as H gas, deuterium-containing gas, and NH gas (hereinafter, for convenience, also referred to as R gas), and a film formation inhibitor supply source 56 that supplies a film formation inhibitor.

[0048] A TiI4 gas supply line 61 extends from the TiI4 gas supply source 51, and a SiH4 gas supply line 62 extends from the SiH4 gas supply source 52. The other ends of the TiI4 gas supply line 61 and the SiH4 gas supply line 62 are connected to the above-mentioned gas inlet holes 45a and 45b, respectively.

[0049] The first N2 gas supply source 53 is connected to a first N2 gas supply line 63 that supplies N2 gas to the TiI4 gas supply line 61 side. The second N2 gas supply source 54 is connected to a second N2 gas supply line 66 that supplies N2 gas to the SiH4 gas supply line 62 side.

[0050] The first N2 gas supply line 63 branches into a first continuous N2 gas supply line 64, which constantly supplies N2 gas during ALD film formation, and a first flush purge line 65, which only supplies N2 gas during the purge process. The second N2 gas supply line 66 branches into a second continuous N2 gas supply line 67, which constantly supplies N2 gas during ALD film formation, and a second flush purge line 68, which only supplies N2 gas during the purge process. The other end of the first continuous N2 gas supply line 64 is connected to the TiI4 gas supply line 61, and the other end of the first flush purge line 65 is connected to the first continuous N2 gas supply line 64. The other end of the second continuous N2 gas supply line 67 is connected to the SiH4 gas supply line 62, and the other end of the second flush purge line 68 is connected to the second continuous N2 gas supply line 67. Since the first flush purge line 65 and the second flush purge line 68 have a high flow rate, the first continuous N2 gas supply line 64 and the second continuous N2 gas supply line 67 are provided with orifices 83 and 84, respectively, to prevent backflow.

[0051] An R gas supply line 69 extends from the R gas supply source 55, and a film formation inhibitor supply line 70 extends from the film formation inhibitor supply source 56. The other end of the H gas supply line 69 is connected to a second continuous N gas supply line 67, and the other end of the film formation inhibitor supply line 70 is connected to the H gas supply line 69.

[0052] The TiI gas supply line 61 is equipped with a valve V1, a buffer tank 81, and a flow meter 71, in that order from the bottom. The SiH gas supply line 62 is equipped with a valve V2, a buffer tank 82, and a flow controller 72, in that order from the downstream side. The buffer tanks 81 and 82 are used to temporarily store the gases, and by storing the gases in these tanks, increasing the pressure therein, and then supplying the stored gas, a large flow rate of the gas can be supplied into the chamber 1. Buffer tanks may be provided in the first and second flush purge lines 65 and 68, which supply a large flow rate of N gas.

[0053] The first continuous N2 gas supply line 64, the first flush purge line 65, the second continuous N2 gas supply line 67, and the second flush purge line 68 are respectively equipped with valves V3, V4, V5, and V6 on their downstream sides and flow rate controllers 73, 74, 75, and 76 on their upstream sides. The R gas supply line 69 and the film formation inhibitor supply line 56 are respectively equipped with flow rate controllers 77 and 78. In addition, a valve V7 is installed in the H2 gas supply line 69 downstream of the junction with the film formation inhibitor supply line 70.

[0054] Valves V1 to V7 function as ALD valves for switching gases during ALD, and are configured as high-speed valves that can be opened and closed at high speed.

[0055] Although not shown, the gas supply mechanism 5 also has a ClF gas supply line that supplies ClF gas as a cleaning gas for cleaning the inside of the chamber 1. It also has a bottom N gas supply line that supplies N gas from the bottom of the chamber 1.

[0056] Since TiI4 is a solid at room temperature, TiI4 gas supply source 51 has the function of sublimating solid TiI4, as shown in Fig. 13. Specifically, TiI4 gas supply source 51 has solid source tank 90 that stores TiI4, which is solid at room temperature. A heater 90a is provided around solid source tank 90, and the TiI4 in tank 90 is heated to an appropriate temperature to sublimate the TiI4.

[0057] A carrier gas pipe 91 for supplying N2 gas as a carrier gas from above is inserted into the solid source tank 90. ​​A carrier N2 gas supply source 92 is connected to the carrier gas pipe 91. A flow rate controller 91a is installed in the carrier gas pipe 91. The above-mentioned TiI4 gas supply line 61 is inserted into the solid source tank 90 from above. A heater (not shown) is installed in the TiI4 gas supply line 61 to prevent condensation of the TiI4 gas. TiI4 gas sublimated in the solid source tank 90 is transported by the carrier N2 gas and supplied to the TiI4 gas supply line 61. An offset N2 gas supply line 93 is connected to the TiI4 gas supply line 61 upstream of the flow meter 71, and an N2 gas supply source 94 is connected to the offset N2 gas supply line 93. A flow rate controller 93a and a valve 93b are installed in the offset N2 gas supply line 93. The flow rate of TiI 4 gas is adjusted by a flow rate controller 91 a of the carrier gas pipe 91 and a flow rate controller 93 a of the offset N 2 gas supply line 93 .

[0058] The carrier gas pipe 91 and the TiI4 gas supply line 61 are connected by a bypass pipe 97, and a valve 97a is provided in the bypass pipe 97. Valves 95a and 95b are provided upstream and downstream of the bypass pipe 97 connection point in the carrier gas pipe 91, respectively. Valves 96a and 96b are provided upstream and downstream of the bypass pipe 97 connection point in the TiI4 gas supply line 61, respectively. By closing the valves 95b and 96a and opening the valves 95a, 96b, and 97a, N gas from the carrier N2 gas supply source 93 can be purged through the carrier gas pipe 91, the bypass pipe 97, and the TiI4 gas supply line 61. The TiI4 gas supply line 61 can also be purged with N2 gas from the offset N2 gas supply line 93.

[0059] When purging the chamber 1, flush purge N2 gas can be supplied from the first flush purge line 65 and the second flush purge line 68 to strengthen the purge, but the first and second flush purge lines 65, 68 are not essential. Also, the buffer tanks 81, 82 are not essential.

[0060] The control unit 6 is composed of a computer and includes a main control unit with a CPU, input devices (keyboard, mouse, etc.), output devices (printer, etc.), display devices (display, etc.), and a storage device (storage medium). The main control unit controls the operation of each component, such as opening and closing valves V1 to V7, adjusting the gas flow rate using flow rate controllers 72 to 78, adjusting the pressure inside the chamber 1 using a pressure control valve, and adjusting the temperature of the substrate W using a heater 31. These operations are controlled by a process recipe, which is a control program stored in a storage medium (hard disk, optical disk, semiconductor memory, etc.) built into the storage device.

[0061] In the film forming apparatus 100 configured as above, the control unit 6 controls the heating by the heater 31 so that the temperature of the substrate W placed on the susceptor 2 is 450°C or lower, for example, 350°C.

[0062] In this state, first, the gate valve G is opened, and the substrate W is carried into the chamber 1 from the vacuum transfer chamber by a transfer device (neither of which is shown), and placed on the susceptor 2. Prior to being transferred to the chamber 1, the substrate W may be subjected to a pre-cleaning process or the like in a separate chamber to remove any native oxide film, if necessary.

[0063] After the substrate W is placed and the transfer device is retracted, the gate valve G is closed and the susceptor 2 is raised to the processing position. Next, the chamber 1 is evacuated by the exhaust unit 4, and valves V3 and V5 are opened to continuously supply N2 gas into the processing space S of the chamber 1 via the first continuous N2 gas supply line 64 and the second continuous N2 gas supply line 67. This maintains the interior of the chamber 1 at a reduced pressure of 13 to 6650 Pa (0.1 to 50 Torr), and stabilizes the temperature of the substrate W on the susceptor 2 at a desired temperature of 450°C or less, for example, 350°C.

[0064] Then, while maintaining the state in which N2 gas is continuously supplied, the valves V1 and V2 of the TiI4 gas supply line 61 and the SiH4 gas supply line 62 are operated to alternately and intermittently supply TiI4 gas and SiH4 gas to the contact formation region of the substrate W by ALD. x Form a film.

[0065] FIG. 14 is a diagram showing an example of a gas supply sequence when a TiSix film is formed by the film forming apparatus of FIG. During processing, valves V3 and V5 are kept open, and N2 gas continues to be supplied via the first continuous N2 gas supply line 64 and the second continuous N2 gas supply line 67. Then, valve V1 is first opened, and TiI4 gas is supplied via the TiI4 gas supply line 61 into the processing space S in the chamber 1 (operation S1). This causes the TiI4 gas to be adsorbed onto the surface of the substrate W. At this time, the TiI4 gas is temporarily stored in a buffer tank 81, and after being pressurized, is supplied into the chamber 1.

[0066] Next, valve V1 is closed to stop the supply of TiI4 gas, and the processing space S of chamber 1 is purged (operation S2). For purging at this time, valves V4 and V6 are opened, and in addition to the continuously supplied N2 gas, N2 gas (flush purge N2 gas) is also supplied from the first flush purge line 65 and the second flush purge line 68. This allows the large flow of N2 gas to quickly exhaust excess TiI4 gas and the like from the processing space S.

[0067] Next, valves V4 and V6 are closed to stop the flush purge N2 gas, and valve V2 is opened to supply SiH4 gas into the processing space S in the chamber 1 via the SiH4 gas supply line 62 (operation S3). This causes the adsorbed TiI4 gas to react with the SiH4 gas. At this time, the SiH4 gas is temporarily stored in the buffer tank 82, and then supplied into the chamber 1 after being pressurized.

[0068] Next, valve V2 is closed to stop the supply of SiH4 gas, and the processing space S of chamber 1 is purged (operation S4). For purging at this time, valves V4 and V6 are opened, and in addition to the continuously supplied N2 gas, N2 gas (flush purge N2 gas) is also supplied from the first flush purge line 65 and the second flush purge line 68. This allows the large flow of N2 gas to quickly exhaust excess SiH4 gas and the like from the processing space S.

[0069] By performing the above steps S1 to S4 in one cycle in a short time, a thin TiSi x By forming a unit film and repeating this cycle of steps a predetermined number of times, a TiSi film of a desired thickness can be formed. x The TiSi film is formed. x The thickness of the film can be controlled by the number of times the above cycle is repeated.

[0070] In addition to SiH4 gas, the reduction reaction can be facilitated by using other reducing gases (R gases) such as H2 gas, deuterium-containing gas, and NH3 gas from the R gas supply source 55. The supply timing of the other reducing gas is not particularly limited, and for example, the other reducing gas may be supplied simultaneously with each supply of Si-containing gas, or may be supplied partly with the supply of Si-containing gas, for example, once every several times. Furthermore, the other reducing gas may be supplied at the same time as TiI4 gas is supplied, or may be supplied at a different timing from SiH4 gas and TiI4 gas.

[0071] The film-forming inhibitor can be supplied from the film-forming inhibitor supply source 56 as needed. By supplying the film-forming inhibitor, as described above, TiSi x The film formation inhibitor is adsorbed in the area where you do not want the film to be formed, and TiSi x The timing of supplying the film formation inhibitor is such that after the substrate W is placed on the susceptor 2, the TiSi x ALD can be performed prior to the formation of a TiSi film. x A film formation inhibitor may be supplied when forming a film. For example, the film formation inhibitor may be supplied sequentially after operation S2 or operation S4, or may be supplied when TiI gas or SiH gas is supplied in operation S1 or operation S3. The film formation inhibitor may be supplied both when TiI gas is supplied and when SiH gas is supplied.

[0072] After processing one substrate W is completed, the chamber 1 is purged with N2 gas, and the susceptor 2 is lowered to the transfer position. Next, the gate valve G is opened, a transfer device is inserted from the vacuum transfer chamber, and the substrate W on the susceptor 2 is transferred out of the chamber 1.

[0073] TiSi x The substrate W on which the film has been formed may be transferred to another chamber and subjected to plasma treatment using H2 plasma or the like.

[0074] In the film forming apparatus 100, after the film forming process for a certain number of substrates W is completed, the chamber 1 may be cleaned by supplying ClF3 gas as a cleaning gas from the ClF3 gas supply line. The cleaning is performed by supplying ClF3 gas into the chamber 1 with no substrates W present in the chamber 1. The inner wall of the chamber 1 is heated to about 100 to 350°C, and TiSi x Although the adhesion of the film is suppressed, it cannot be completely eliminated. Therefore, the TiSi x The membrane is removed.

[0075] The TiSi film formed by ALD in the film forming apparatus 100 described above x In film formation, highly reactive TiI4 gas is adsorbed on the substrate W to a monolayer with good control, and then reacted with SiH4 gas to form an extremely thin TiSi x This process is repeated several times to form a unit film. x Furthermore, due to the high controllability, it is possible to form a thin TiSi film of 0.5 to 10 nm. x Furthermore, a TiSi film can be formed directly on the contact formation area by ALD. x By forming a film, it is possible to suppress the absorption of impurities from the contact formation region and reduce the resistance of the Si contact.

[0076] Furthermore, during the purging of operations S2 and S4, in addition to the continuously supplied N2 gas, N2 gas (flush purge N2 gas) is also supplied from the first flush purge line 65 and the second flush purge line 68, resulting in high gas replacement efficiency. This allows for purging in a short period of time and high film thickness controllability. Furthermore, buffer tanks 81 and 82 are provided on the TiI4 gas supply line 61 and the SiH4 gas supply line 62, respectively, so that TiI4 gas and SiH4 gas are temporarily stored therein before being discharged. This makes it easier to supply TiI4 gas and SiH4 gas in a short period of time, ensuring that the required amount is supplied even when one cycle is short.

[0077] <Other applications> Although the embodiments have been described above, the disclosed embodiments should be considered to be illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0078] For example, in the above embodiment, TiSi x Although the case of forming a film has been mainly described, the present invention may also be applied to contact formation regions of memory semiconductors such as DRAM and 3D NAND.

[0079] Furthermore, the film formation apparatus shown in FIG. 12 is merely an example, and may be a single-sheet film formation apparatus with a different structure from that shown in FIG. 12, or a batch-type film formation apparatus that forms films on multiple substrates at once. Furthermore, it may be a film formation apparatus that achieves ALD by relative movement between a gas supply region and a substrate. Examples of such film formation apparatus include a semi-batch type in which multiple substrates are placed on a rotatable stage and, while the stage is rotating, the substrates pass through the supply regions of each gas to achieve ALD film formation. It may also be a semi-batch type film formation apparatus in which multiple substrates are placed on a non-rotating stage and ALD film formation is performed.

[0080] In the above embodiment, a semiconductor wafer is used as an example of the substrate, but the substrate is not limited to a semiconductor wafer and may be any substrate having a contact formation region for forming a Si contact. For example, the substrate may be a glass substrate used in an FPD (flat panel display) or a ceramic substrate. [Explanation of symbols]

[0081] 1; Chamber 2; susceptor 3. Shower head 4. Exhaust section 5. Gas supply mechanism 6; Control unit 51; TiI4 gas source 52: SiH4 gas source 53,54;N2 gas supply source 55;Other reducing gas (R gas) sources 56; Source of film formation inhibitors 100; Film deposition equipment 101; Substrate 102; insulating film 103; Contact hole 104: Contact formation region 105;TiSi x film 106; Wiring 107;Film formation inhibitor S: Processing space W; substrate

Claims

1. 1. A method for forming a titanium silicide film in a contact formation region of a substrate, comprising: a step of preparing a substrate having an insulating film formed on a base body and having a contact hole, the contact hole having a contact formation region exposed at the bottom of the contact hole, the contact formation region being a silicon-containing region into which impurities have been diffused; selectively adsorbing a film-formation inhibitor that inhibits the formation of a titanium silicide film on a portion of the substrate other than the contact formation region; The substrate temperature was set to 450° C. or less, and TiI was used as a Ti precursor. ４ a step of sequentially supplying a titanium silicide film to the substrate by ALD without reacting with silicon contained in the contact formation region, and a silicon-containing gas serving as a reducing gas for reducing the TiI gas to form a silicide, to the substrate; A film forming method comprising:

2. 2. The film forming method according to claim 1, wherein the contact formation region is a region where Si or SiGe is epitaxially grown.

3. 3. The film formation method according to claim 1, wherein the film formation inhibitor is an alkyl halide or an alkene.

4. 4. The film forming method according to claim 1, wherein the step of selectively adsorbing the film-forming inhibitor is performed prior to the step of forming the titanium silicide film or during the step of forming the titanium silicide film.

5. The Si-containing gas is Si ２ H ６ , SiH ４ , Si ２ I ６ , SiI ４ , SiHI ３ , SiH ２ I ２ , SiH ３ I, Si ２ Cl ６ , SiCl ４ , SiHCl ３ , SiH ２ Cl ２ , SiH ３ Cl, Si ２ Br ６ , SiBr ４ , SiHBr ３ , SiH ２ Br ２ , SiH ３ Br, Si ２ F ６ , SiF ４ , SiHF ３ , SiH ２ F ２ , SiH ３ The film forming method according to claim 1 , wherein the fluorine atom is selected from the group consisting of fluorine, ...

6. The step of forming the titanium silicide film includes, in addition to the Si-containing gas, a reducing gas such as H ２ Gas, deuterium-containing gas, NH ３ The film forming method according to claim 1 , further comprising supplying at least one gas.

7. a step of preparing a substrate having an insulating film formed on a base body and having a contact hole, the contact hole having a contact formation region exposed at the bottom of the contact hole, the contact formation region being a silicon-containing region into which impurities have been diffused; selectively adsorbing a film-formation inhibitor that inhibits the formation of a titanium silicide film on a portion of the substrate other than the contact formation region; The substrate temperature was set to 450° C. or less, and TiI was used as a Ti precursor. ４ a step of sequentially supplying a titanium silicide film, which is a silicon contact, to the substrate by ALD without reacting with silicon contained in the contact formation region, and a silicon-containing gas serving as a reducing gas for reducing the TiI gas to form a silicide, to the substrate; a step of filling the contact holes with a wiring material to form wiring on the titanium silicide film; A method for manufacturing a semiconductor device, comprising:

8. 8. The method for manufacturing a semiconductor device according to claim 7, wherein said contact formation region is a region where Si or SiGe is epitaxially grown.

9. 9. The method for manufacturing a semiconductor device according to claim 7, wherein the film formation inhibitor is an alkyl halide or an alkene.

10. 10. The method for manufacturing a semiconductor device according to claim 7, wherein the step of selectively adsorbing the film-forming inhibitor is performed prior to the step of forming the titanium silicide film or during the step of forming the titanium silicide film.

11. 11. The method for manufacturing a semiconductor device according to claim 7, wherein the wiring material is any one of Co, W, Mo, and Ru.

12. The Si-containing gas is Si ２ H ６ , SiH ４ , Si ２ I ６ , SiI ４ , SiHI ３ , SiH ２ I ２ , SiH ３ I, Si ２ Cl ６ , SiCl ４ , SiHCl ３ , SiH ２ Cl ２ , SiH ３ Cl, Si ２ Br ６ , SiBr ４ , SiHBr ３ , SiH ２ Br ２ , SiH ３ Br, Si ２ F ６ , SiF ４ , SiHF ３ , SiH ２ F ２ , SiH ３ 12. The method for manufacturing a semiconductor device according to claim 7, wherein the compound is selected from the group consisting of fluorine, fluorine-containing ...

13. The step of forming the titanium silicide film includes, in addition to the Si-containing gas, a reducing gas such as H ２ Gas, deuterium-containing gas, NH ３ The method for manufacturing a semiconductor device according to claim 7 , further comprising supplying at least one type of gas.

14. 1. A film formation apparatus for forming a titanium silicide film in a contact formation region of a substrate, the contact formation region being a silicon-containing region into which impurities have been diffused, the apparatus comprising: a processing vessel in which a substrate is accommodated; a mounting table on which a substrate is placed within the processing chamber; a heating unit that heats the substrate on the mounting table; The treatment vessel was charged with TiI as a Ti precursor. ４ a gas supply unit that supplies a gas containing a Si-containing gas as a reducing gas that reduces the TiI gas to form a silicide, and a film-forming inhibitor that inhibits the formation of a titanium silicide film on a portion of the substrate other than the contact formation region; Control unit and and The control unit With the substrate having the contact formation region provided in the processing chamber, the film-formation inhibitor is supplied into the processing vessel, and the film-formation inhibitor that inhibits the formation of a titanium silicide film on a portion of the substrate other than the contact formation region is selectively adsorbed; The TiI ４ a titanium silicide film formed in the contact formation region of the substrate by ALD without reacting with silicon contained in the contact formation region, by sequentially supplying a titanium silicide gas and the Si-containing gas to the substrate, and controlling the heating unit and the gas supply unit.

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