Substrate processing method and substrate processing apparatus

Abstract

The present disclosure relates to a substrate processing method and a substrate processing apparatus. In a case where a first metal film composed of a metal other than Ru is siliconized on a Si-containing layer exposed on a surface of a substrate, the Si-containing layer is prevented from being siliconized. The substrate processing method of the present disclosure includes the following steps: forming a first metal film composed of a metal other than Ru on a Si-containing layer exposed on a surface of a substrate; and supplying a Si element to the substrate, and forming a metal silicide film from the Si element and the first metal film.

Description

Technical Field

[0001] This disclosure relates to a substrate processing method and a substrate processing apparatus. Background Technology

[0002] In the manufacture of semiconductor devices, various metal films are deposited on the surface of a semiconductor wafer (hereinafter referred to as the substrate) that serves as a substrate, after forming a recess, in order to set a wiring layer. It is known that, in order to reduce the contact resistance between the wiring layer and the Si (silicon) layer of the substrate, a metal film such as a Ti (titanium) film is deposited at the bottom of the recess to form a silicide.

[0003] Patent Document 1 describes the following: After depositing Ti at the bottom of a connection hole on the surface of a substrate by sputtering, Ti is deposited in the connection hole by plasma CVD, and Al (aluminum) is embedded to form wiring.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 10-223570 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] This disclosure provides a technique for suppressing the silanization of the Si-containing layer when a first metal film, consisting of a Si-containing layer exposed on the surface of a substrate and made of a metal other than Ru (ruthenium), is silanized.

[0009] Solution for solving the problem

[0010] The substrate processing method disclosed herein includes the following steps: forming a first metal film composed of a metal other than Ru in a Si-containing layer exposed on the surface of the substrate; and supplying Si element to the substrate, thereby forming a metal silicide film from the Si element and the first metal film.

[0011] The effects of the invention

[0012] This disclosure enables the suppression of Si-containing layer silanization when a first metal film consisting of a Si-containing layer exposed on the surface of a substrate and made of a metal other than Ru is silanized. Attached Figure Description

[0013] Figure 1 This is a longitudinal sectional side view showing the surface layer of the substrate before processing in the embodiments and comparative methods.

[0014] Figure 2A This is a partial cross-sectional view of the substrate surface layer that changes through a comparative process.

[0015] Figure 2B This is a partial cross-sectional view of the substrate surface layer that changes through a comparative process.

[0016] Figure 2C This is a partial cross-sectional view of the substrate surface layer that changes through a comparative process.

[0017] Figure 3 This is a longitudinal sectional side view of the surface layer of the substrate after the comparison method is shown.

[0018] Figure 4A This is a partial cross-sectional view of the substrate W, which varies depending on the implementation method.

[0019] Figure 4B This is a partial cross-sectional view of the substrate W, which varies depending on the implementation method.

[0020] Figure 5A This is a partial cross-sectional view of the substrate W, which varies depending on the implementation method.

[0021] Figure 5B This is a partial cross-sectional view of the substrate W, which varies depending on the implementation method.

[0022] Figure 5C This is a partial cross-sectional view of the substrate W, which varies depending on the implementation method.

[0023] Figure 6 This is a longitudinal sectional side view showing the surface layer of the processed substrate according to the embodiment.

[0024] Figure 7 This is a top view showing the substrate processing apparatus for performing the embodiment.

[0025] Figure 8 This is a longitudinal sectional side view showing the processing module within the substrate processing apparatus.

[0026] Figure 9 This is a timing diagram showing the supply and disconnection of each gas in the processing module.

[0027] Figure 10 This is the first SEM image showing the surface layer of the bare wafer after evaluation test 1.

[0028] Figure 11 This is a second SEM image showing the surface layer of the bare wafer after evaluation test 1.

[0029] Figure 12 This is a longitudinal cross-sectional view showing the surface changes of the substrate before and after evaluation test 2.

[0030] Figure 13 This is a graph showing the results of the evaluation of experiment 2. Detailed Implementation

[0031] <Film formation of metal silicide films involved in the comparison method>

[0032] Before describing the method for forming metal silicide films as disclosed herein, the treatment of comparative methods related to the subject matter of this disclosure will be explained. Figure 1 This diagram shows the surface layer of the substrate before the processing according to the present disclosure and comparative method. On the surface layer of the substrate W undergoing the processing based on the present disclosure and comparative method, a Si layer 11 and a SiN (silicon nitride) layer 12 stacked on the Si layer 11 are provided as a Si-containing layer. Furthermore, by forming through-holes such as holes and trenches in the SiN layer 12, a recess 13 with openings on the surface of the substrate W is formed, exposing the bottom surface of the recess 13. The sidewalls of the recess 13 are formed by the SiN layer 12. Moreover, as part of the processing of the present disclosure and the comparative method, a series of processes are performed, including forming a Ti film (first metal film) 14 at the bottom of the recess 13 and siliconizing the Ti film 14 by heating. Furthermore, the substrate W is, for example, a semiconductor wafer.

[0033] Figures 2A-2C These are partial cross-sectional views of the substrate surface that have changed through comparative processing. In these views, the black arrows represent the diffusion of Ti (titanium), and the hollow arrows represent the diffusion of Si. Figure 2B , Figure 2C The dashed line represents the surface position of the Si layer 11 before the Ti film 14 is formed, that is, the interface position between the Ti film 14 and the Si layer 11 at the beginning of Ti film formation. Regarding the above, in relation to the following description of this disclosure... Figures 4A to 5C The same applies to the middle. Moreover, the interface between the initial Ti film 14 and the Si layer 11, as shown by the dashed line, is sometimes simply referred to as the initial interface.

[0034] First, at the bottom of the recess 13 of the substrate W, Ti (Ti) is gradually deposited to form a Ti film 14 by plasma CVD. Figure 2A At this time, between the Ti film 14 and the Si layer 11 in contact with the Ti film 14, due to the heating of the substrate W during Ti film formation, the Ti and Si that constitute the Ti film 14 and the Si layer, respectively, diffuse into each other through the initial interface according to the concentration gradient of Ti and Si. Figure 2B That is, Ti constituting the Ti film 14 diffuses into the Si layer 11, and Si constituting the Si layer 11 diffuses into the Ti film 14. Because the amount of Ti deposited is large (i.e., the Ti film 14 is relatively thick), a relatively large amount of Ti diffuses into the Si layer 11, and this Ti moves significantly downwards and laterally into the Si layer 11. Therefore, as... Figure 2CAs shown, the TiSi film 15 is formed by significantly eroding the Si layer 11. Specifically, the TiSi film 15 is formed such that its lower end separates significantly downwards from the initial interface, and the side edges of the TiSi film 15 are located below the SiN layer 12. Therefore, it can also be said that a relatively large amount of Si layer 11 is consumed during the formation of the TiSi film 15.

[0035] Figure 3 This is a diagram showing the surface layer of the substrate after the comparative treatment. The completed TiSi film 15 has relatively high conductivity and forms the contact between the wiring layer 19 and the Si layer 11 to be formed later. Because the TiSi film 15 is formed in a manner where the Si layer 11 is significantly etched, it may cause an increase in leakage current and other electrical performance defects in the semiconductor device manufactured from the substrate W. Figure 3 ).

[0036] <Film Formation of Metal Silicate Films as Represented in This Disclosure>

[0037] Figures 4A to 5C This is a partial cross-sectional view of the substrate W, which varies according to the processing described in this disclosure (the processing of the embodiment). In the processing of the embodiment, the erosion of the TiSi film 15 in the Si layer 11 as described above is suppressed. The following processes are performed by storing the substrate W in a processing container with its interior vented and set to vacuum pressure, and supplying each gas into the processing container. The substrate W is heated to a predetermined temperature suitable for processing.

[0038] For processing containers Figure 1 The substrate W shown is supplied with gases such as TiCl4 (titanium tetrachloride), H2 (hydrogen), and Ar (argon). A Ti film 14 is formed on the Si layer 11 at the bottom of the recess 13 by plasma CVD, which is performed by plasmaizing these gases. Figure 4AAlthough the film formation time of the Ti film 14 corresponds to the structure of the film formation apparatus and other processing conditions, the film formation time is set to be relatively short so that the thickness of the Ti film 14 is relatively small. For example, the Ti film 14 is formed with a thickness L of 5 nm or less based on the initial interface. In this way, since the thickness of the Ti film 14 is small, it can be said that the Ti concentration on the Si layer 11 is low. Therefore, diffusion of Si and Ti caused by the concentration gradient between the Ti film 14 and the Si layer 11 is less likely to occur. Therefore, even if such a Ti film 14 is formed, the formation of the TiSi film 15 can be suppressed, thereby suppressing the erosion of the Si layer 11 by the TiSi film 15. Furthermore, although the thickness L of the Ti film 14 based on the initial interface has been described as 5 nm or less, the case where a part of the Ti film 14 changes into the TiSi film 15 is also taken into consideration. Therefore, more specifically, the thickness L based on the initial interface of the Ti film 14 or the TiSi film 15 is 5 nm or less.

[0039] Next, as Figure 4B As shown, CVD is performed by supplying a gas such as SiH4 (silane) into the processing vessel as the Si supply gas to deposit a Si film 16 on a Ti film 14. By heating the substrate W used for this film formation, interdiffusion occurs between the Ti film 14 and the Si film 16 according to the concentration gradients of Ti and Si. That is, Ti contained in the Ti film 14 diffuses into the Si film 16, and Si contained in the Si film 16 diffuses into the Ti film 14, forming a TiSi film 15 from the Ti film 14 and the Si film 16. In other words, the Ti film 14 is silicided by the Si film 16. Figure 5A ).

[0040] Furthermore, the Si film 16 is not limited to being formed in a manner that completely covers the Ti film 14. Alternatively, a small amount of Si may be deposited on the Ti film 14 to the extent that no film is formed, but in this description, as... Figure 4B As shown, progress is made in the process where a Si film 16 is formed in a manner that covers the entire Ti film 14.

[0041] In this embodiment, the Si supply source for forming the TiSi film 15 is Si from a Si supply gas containing Si elements. Furthermore, when Ti-Si interdiffusion occurs between the Si film 16 and the Ti film 14, which are formed from gas, Ti-Si interdiffusion sometimes also occurs between the Ti film 14 and the Si layer 11. That is, in this embodiment, the Si layer 11 may also become a Si supply source for forming the TiSi film 15. However, by supplying Si from the Si film 16 to the Ti film 14 to increase the Si concentration in the Ti film 14, the Ti-Si interdiffusion between the Ti film 14 and the Si layer 11 caused by the aforementioned concentration gradient is suppressed. Therefore, in this embodiment, the TiSi film 15 is formed on the initial interface in a manner that suppresses erosion of the Si layer 11.

[0042] Subsequently, TiCl4 gas, H2 gas, and Ar gas are supplied into the processing container, and these gases are plasma-enhanced, thereby forming a Ti film 17 on the TiSi film 15. Figure 5B In this film formation process, the substrate W is heated by the heating mechanism of the processing apparatus, and then heated by plasma. This causes Ti, constituting the Ti film 17, to diffuse into the TiSi film 15, and Si, constituting the TiSi film 15, to diffuse into the Ti film 17. The Ti film 17 is also siliconized, thus forming the TiSi film 15. That is, the thickness of the TiSi film 15 increases (…). Figure 5C ).

[0043] Furthermore, as described above, in order to suppress the erosion of the Si layer 11 by the TiSi film 15 and reduce the film thickness L of the Ti film 14, therefore Figure 5B The thickness L1 of the Ti film 17 shown is, for example, greater than the thickness L of the Ti film 14. Furthermore, since the Ti film 17 is changed to the TiSi film 15, the thickness L1 of the Ti film 17 is more specifically the thickness of the TiSi film 15, which is equivalent to the amount of increase in the thickness of the TiSi film 15 from the end time point of the Si film 16 to the end time point of the Ti film 17.

[0044] like Figure 5C As shown, after a TiSi film 15 of sufficient thickness is formed, a film-forming gas for metal embedding is supplied into the processing container. Thereby, a second metal film, namely a wiring layer 19, made of, for example, Ru (ruthenium), is formed on the TiSi film 15 in a manner that embeds it into the recess 13. Figure 6 ).

[0045] Through the above-described embodiments, it is possible to suppress the erosion of the Si layer 11 by the TiSi film 15 while forming a TiSi film 15 of sufficient thickness on the substrate W. Since the TiSi film 15 serving as the contact portion has sufficient thickness, it is possible to ensure good electrical connection between the wiring layer 19 and the Si layer 11, and to suppress poor electrical performance as described above.

[0046] The processing of the embodiments described in Figures 4 and 5 above will be further explained. As described above, in this embodiment, Si constituting silane gas is used when forming the TiSi film 15, thereby suppressing the consumption of Si in the Si layer 11 to form the TiSi film 15. Regarding the timing of supplying the gas for supplying Si, it is assumed to be after the Ti film 14 has been formed. This is because, as shown in the evaluation test described later, even if silane gas is supplied to the Si layer 11, Si in the gas is difficult to adsorb onto the Si layer 11. However, if the Ti film 14 is formed on the Si layer 11, Si can be adsorbed more efficiently relative to the Ti film 14, thus serving as a material for forming the TiSi film 15. However, when Ti is excessively deposited on the Si layer 11 (the Ti film 14 becomes thicker), as explained in the comparative example, the erosion of the Si layer 11 by the TiSi film 15 becomes more significant. Therefore, in the process of the embodiment, silane gas is supplied to the substrate W while a thin Ti film 14 is formed, so that the Si contained in the gas becomes the material for forming the TiSi film 15.

[0047] Alternatively, if Ti diffuses sufficiently from the Ti film 14 into the Si film 16 through the Si film 16 formation illustrated in Figure 4(C), and the heating of the substrate W accompanying the formation, and the thickness of the TiSi film 15 formed by the Si film 16 formation is sufficient, then this step may not be necessary. Figure 5B , Figure 5C The Ti film 17 shown is formed during the film deposition process. However, when the Si film 16 is set to a thickness that allows for sufficient Ti diffusion, the thickness becomes relatively small. Therefore, at the point in time when the film deposition process of the Si film 16 ends and the TiSi film 15 is formed from the Si film 16 ( Figure 5A At the time point shown, the TiSi film 15 may not have sufficient thickness. To ensure that the TiSi film 15 has sufficient thickness, it is preferable to form the Ti film 17. That is, it is preferable to perform the deposition of the first metal film (Ti film) multiple times, and after the deposition of the first metal film, before the deposition of the next first metal film, to deposit a gas for supplying Si to form the Si film 16, thereby forming a metal silicide film from each of the first metal films.

[0048] Alternatively, a Si film 16 can be formed after the Ti film 17 is formed, allowing Ti constituting the Ti film 17 to diffuse into the Si film 16, further thickening the TiSi film 15. That is, the formation of the Ti film and the Si film can be performed alternately, with multiple formations of each film. Furthermore, when alternating the formation of the Ti film and the Si film in this manner, the Ti film can be formed last, or the Si film can be formed last.

[0049] Furthermore, when supplying Si to the substrate W to allow it to adsorb onto the substrate W, it was described that SiH4 (silane) was used as the gas for supplying Si, which is a compound containing Si. However, it is not limited to using SiH4 gas; for example, Si2H6 (disilane) could also be used. However, when using Si2H6 gas, it is easy to form an unwanted Si film on the SiN layer 12 that forms the sidewall of the recess 13. In other words, the selectivity of Si film formation between the Ti film 14 and the SiN layer 12 is low. On the other hand, when using SiH4 gas, as shown in the evaluation test described later, Si is selectively formed on the Ti film 14 compared to the SiN layer 12.

[0050] This is believed to be because, at relatively high temperatures, SiH4 decomposes after adsorption onto the metal film, producing SiH2, which becomes the raw material for forming the Si film. In the SiH4 state, the adsorption capacity for silicon-containing compounds (meaning they are contained as constituent elements rather than as impurities), such as Si layer 11 and SiN layer 12, is low. In contrast, Si2H6 decomposes to produce SiH2 before adsorption onto each film, and this SiH2 has a relatively high adsorption capacity for metals such as Ti and silicon-containing compounds. Therefore, it is preferable to use SiH4 as the gas for supplying Si, thereby enabling SiH2 to selectively adsorb onto the Ti film 14 and preventing film formation on the SiN layer 12.

[0051] Furthermore, when SiH4 gas is supplied to substrate W as described above, Si adsorption is highly efficient due to the existing Ti film 14. Therefore, when supplying the SiH4 gas to substrate W, the temperature of substrate W can be set to, for example, 450°C or below, and the pressure inside the processing container storing the substrate can be set to, for example, 1 Torr or below. Evaluation tests described later confirmed that Si adsorption onto substrate W can occur at such temperature and pressure. Furthermore, it was also confirmed that adsorption can occur even at a temperature of 400°C on substrate W.

[0052] <Substrate processing apparatus according to the embodiments>

[0053] The substrate processing apparatus 1 that performs the processing described above will now be explained. Figure 7 This is a top view showing the substrate processing apparatus. The substrate processing apparatus 1 is equipped with a substrate processing unit for performing... Figures 4A to 5C The processing module 5a described herein is for a series of processes, and the processing module 5b is for forming the wiring layer 19. The processing module 5a is equivalent to the Ti film forming section and the metal silicide film forming section.

[0054] The substrate processing apparatus 1 is configured such that, from front to rear, it comprises an atmospheric transport module 2, two load-locked vacuum modules 3, a vacuum transport module 4, and processing modules 5a and 5b. The load-locked vacuum module is sometimes referred to as an LLM. The atmospheric transport module 2 has a housing 21, the interior of which is set to atmospheric pressure. A transport mechanism 22 is provided within the housing 21, which is, for example, configured as a multi-joint arm that can move freely left and right. Furthermore, the atmospheric transport module 2 has, for example, three loading ports 23 for transferring the substrate W between the transport container C and the LLM 3, arranged horizontally.

[0055] Each loading port 23 comprises: a platform 24 for transporting container C, which is disposed on the front side relative to housing 21; a transport port, which is disposed on the side wall of housing 21 facing the transport container C on the platform 24; and a door 25 for opening and closing the transport port. Furthermore, the transport container C is configured to hold multiple substrates W, for example, a container called FOUP (Front Opening Unified Pod), and the transport mechanism 22 transports substrates W between the transport container C and LLM 3.

[0056] The LLM 3 includes a housing 31, configured to appropriately vary the pressure within the housing 31 between atmospheric pressure and a predetermined vacuum pressure. Each housing 31 has two transfer ports for transferring the substrate W into the atmospheric transfer module 2 and the vacuum transfer module 4, and each transfer port is equipped with a gate valve G. A mounting stage 33 for placing the substrate W is provided inside the housing 31. The transfer mechanism 22 of the atmospheric transfer module 2 and the transfer mechanism 43 of the vacuum transfer module 4 (described later) respectively exchange substrate W with the mounting stage 33.

[0057] The vacuum transfer module 4 includes a housing 41, to which LLM 3 and processing modules 5a and 5b are connected via gate valve G. The housing 41 is vented by an exhaust mechanism (not shown), thereby maintaining a vacuum atmosphere at a predetermined pressure during operation of the substrate processing apparatus 1. A transfer mechanism 43, which functions as a multi-joint arm, is provided within the housing 41. The transfer mechanism 43 transfers the substrate W between the processing modules 5a and 5b and the LLM 3.

[0058] The explanation will be based on processing module 5a in each of the processing modules 5a and 5b. Figure 8 This is a longitudinal sectional side view of the processing module 5a. The processing module 5a is configured to continuously supply TiCl4 gas, H2 gas, and argon (Ar) gas to the surface of the substrate W to form Ti films 14 and 17 via plasma CVD. TiCl4 gas is the raw material gas used for film formation, H2 gas is used to remove the influence of chlorine, and Ar gas is used for plasma formation. Additionally, the processing module 5a supplies SiH4 gas to the surface of the substrate W to form a Si film 16.

[0059] The processing module 5a includes a metal processing container 51, which is grounded. The processing container 51 is connected to an exhaust mechanism 52, and exhaust is performed from an exhaust port 53 formed in the bottom wall of the processing container 51. Thus, a predetermined vacuum pressure is maintained inside the processing container 51. Specifically, for example, during film formation ( Figures 4A to 5C The pressure is maintained at 133.3 Pa (1 Torr) or less during the processing. The exhaust mechanism 52 is configured similarly to the exhaust mechanism of LLM 3, allowing adjustment of the exhaust volume within the processing container 51 via a valve and a vacuum pump, thus creating a vacuum atmosphere within the processing container 51 at the desired pressure. Furthermore, a transfer port 54 for the substrate W is formed in the processing container 51, and this transfer port 54 is opened and closed via the aforementioned gate valve G.

[0060] A mounting platform 55, which is circular in plan view, is provided inside the processing container 51 for placing the substrate W. A heater 56, for example made of heating wire, is embedded in the mounting platform 55 to adjust its temperature to, for example, 400°C to 450°C. Similar to the mounting platform 33 of the LLM 3, the mounting platform 55 is also provided with three pins that can protrude and retract from its upper surface, allowing the transfer of the substrate W between the transfer mechanism 43 of the vacuum transfer module 4 and the mounting platform 55. The mounting platform 55 is grounded and disposed within the processing container 51 via a support portion provided at the bottom of the processing container 51. The support portion includes an insulating member (not shown) for insulating the mounting platform 55 from the processing container 51.

[0061] The processing container 51 has an upward-facing opening at its upper part, and a spray head 58 is mounted on the upper part of the processing container 51 via an annular insulating member 57. The spray head 58 is connected to a gas supply mechanism (described later) via a supply flow path, and its interior contains a gas diffusion space from which various gases are supplied from the gas supply mechanism. Furthermore, the spray head 58 has multiple through holes at its lower part for releasing various gases from the gas diffusion space into the processing container 51. The gas supply mechanism 59 is configured to supply TiCl4 gas, H2 gas, Ar gas, and SiH4 gas. Specifically, the gas supply mechanism 59 includes a supply source for each of these gases, valves for switching the supply of each gas into the processing container 51 and stopping the supply, and a mass flow controller for adjusting the supply flow rate of each gas supplied downstream of the aforementioned supply flow path, as well as a flow adjustment unit.

[0062] Furthermore, the spray head 58 is connected to a high-frequency power supply 62, which supplies high-frequency power for plasma formation, via a matching device 61. The processing module 5a constitutes a parallel-plate type plasma processing apparatus via the spray head 58 forming the upper electrode and the mounting stage 55 forming the lower electrode. Moreover, by placing the substrate W on the mounting stage 55 and positioning it in the space between the spray head 58 and the mounting stage 55, supplying TiCl4 gas, H2 gas, and Ar gas, and applying high-frequency power, plasma is generated, causing TiCl4 to decompose and form Ti films 14 and 17. In the processing module 5a, as shown in the test results described later, it is preferable to expose the Ti film 14 in a plasma-enhanced atmosphere for, for example, 30 seconds or less, more preferably 20 seconds. Additionally, the Si film 16 is formed using unplasma-enhanced SiH4 gas supplied from the spray head 58. Therefore, Ti films 14 and 17 are formed based on the supply of TiCl4 gas, H2 gas, and Ar gas, and Si films 14 are formed based on the supply of SiH4 gas at different times.

[0063] The processing module 5b, which forms the wiring layer 19, is configured to supply various gases via a plasma-free CVD method and does not include a matching device 61, a high-frequency power supply 62, or a grounded stage 55. The gas supply mechanism of the processing module 5b has the same structure as that of the processing module 5a, and is configured to supply Ru3(CO) to the substrate W. 12 Ru-containing gases are used as film-forming gases.

[0064] Return to Figure 7As explained, the substrate processing apparatus 1 includes a control unit 10, which functions as a computer. The control unit 10 includes a program, memory, and a CPU. Instructions (steps) are programmed into the program to process and transport the substrate W. This program is stored on a storage medium, such as an optical disc, hard disk, optical disc drive, or DVD, and is installed in the control unit 10. The control unit 10 uses this program to output control signals to each part of the substrate processing apparatus 1, controlling the operation of each part.

[0065] Examples of the operation of the substrate processing apparatus 1, which is controlled by control signals, include the transport of substrate W between modules by the movement of each conveying mechanism and the lifting and lowering of the pins of the platform; the opening and closing of the gate valve G; the pressure adjustment within the housing 31 by gas supply and exhaust in the LLM 3; the gas supply from the spray heads 58 in each processing module 5a, 5b; the pressure adjustment within the processing container 51; and the switching between execution and stop of plasma processing by the on and off of the high-frequency power supply 62.

[0066] Next, use Figures 4A to 5C and Figure 9 The timing diagrams shown illustrate the transport of the substrate W in the substrate processing apparatus 1 and the processing performed by the processing method of this disclosure. The timing diagrams show the supply and interruption of various gases to the processing container 51 in the processing module 5a.

[0067] First, the substrate W with recessed portion 13, which is to be transferred to the transfer container C with loading port 23 of substrate processing apparatus 1, is sequentially transferred to loading interlock vacuum module 3 → vacuum transfer module 4 → processing module 5a. Then, after adjusting the pressure inside processing container 51 to the previously described pressure and the temperature of substrate W to the previously described temperature, TiCl4 gas, H2 gas, and Ar gas are supplied, and plasma is generated from these gases supplied based on high-frequency electricity (time t1). A first Ti film (Ti film 14) is then formed on the surface of substrate W. Figure 4A ).

[0068] Then, the supply of TiCl4 gas, H2 gas, Ar gas, and high-frequency power was stopped, and the supply of SiH4 gas was started (at time t2). Figure 4B The Ti film 14 was siliconized. Figure 5A Next, the SiH4 gas supply is stopped, and TiCl4 gas, H2 gas, and Ar gas are supplied, along with plasma treatment of these gases based on high-frequency power (time t3). A second Ti film (Ti film 17) is then formed on the substrate W with the TiSi film 15 already formed. Figure 5BThis increases the thickness of the TiSi film 15. Then, the supply of TiCl4 gas, H2 gas, Ar gas, and high-frequency power is stopped (at time t4). As mentioned above, the film thickness L of Ti film 14 is smaller than the film thickness L1 of Ti film 17; therefore, for example, the film formation time of the first Ti film (times t1-t2) is shorter than the film formation time of the second Ti film (times t3-t4).

[0069] Then, the substrate W with the TiSi film 15 formed is transferred to the processing module 5b to form the wiring layer 19. Figure 6 The substrate W with the wiring layer 19 formed is transferred to the LLM 3 and then back to the transfer container C at the loading port 23, and then transferred to a substrate processing apparatus for subsequent processing such as chemical mechanical polishing (CMP). Alternatively, necessary processing can be performed appropriately during the period from the formation of the TiSi film 15 by processing module 5a to the formation of the wiring layer 19 by processing module 5b. In such cases, the processing module performing this processing can be connected to the vacuum transfer module 4, for example.

[0070] (Modified Example)

[0071] In this embodiment, an example is described where the formation of Ti films 14 and 17 and the formation of Si film 16 are performed in the same processing module 5a (i.e., within the same processing container). In this case, undesirable chemical reactions may sometimes occur between the gases supplied in each film formation process, and due to these gases, in the components of the processing module 5a, etc. If such a concern exists, the formation of Ti films 14 and 17 and the formation of Si film 16 may be performed in different processing modules (i.e., within different processing containers). Alternatively, if such a concern does not exist, different processing modules may be used. Furthermore, in this case, the processing module for forming Ti films 14 and 17 corresponds to a metal film formation section, and the processing module for forming Si film 16 corresponds to a metal silicide film formation section. Moreover, the processing module 5a in this embodiment corresponds to a module in which the metal film formation section and the metal silicide film formation section are integrally formed.

[0072] Furthermore, in the above-described embodiments, Si is supplied to the Ti film 14 by supplying a gas that is a compound containing Si, but this is not a limitation. For example, Si can be supplied to the Ti film 14 by other methods such as sputtering, but it is preferable to supply SiH4 gas, which can effectively and selectively form the Ti film 14.

[0073] The film formation processes for the Ti film 14 formed in the first Ti film formation process and the Ti film 17 formed in the second Ti film formation process can be different. That is, the processing conditions, such as the pressure inside the processing container 51 and the flow rate of each gas supplied to the processing container 51, can also be different.

[0074] The metal film to be siliconized (the first metal film) and formed on the substrate W is a metal film other than Ru, for example, ... Figures 4A to 5C In addition to the Ti film exemplified, tungsten (W), molybdenum (Mo), zirconium (Zr), and other metals can also be used as constituent elements. Thus, this technology can also be applied to the formation of metal silicides other than TiSi. Furthermore, when forming a first metal film composed of various metals on a substrate W, it can be done by supplying a gas containing that metal to the substrate; any suitable film-forming method can be used. Specifically, the formation of the first metal film is not limited to forming plasma within a processing container. Moreover, film formation is not dependent on CVD; other film-forming methods such as ALD and PVD can also be used.

[0075] In the above embodiment, in order to suppress the decomposition of SiH4 gas into SiH2 and its adsorption onto the SiN layer 12 before adsorption onto the Ti film 14, the SiH4 gas is supplied to the substrate W without plasma treatment. It is preferable that the SiH4 gas is not plasma-treated, but it is also possible to supply it to the substrate W in a plasma-treated manner. When using a gas other than SiH4 gas as the Si supply gas, it may be plasma-treated before being supplied to the substrate W, or it may be supplied to the substrate W without plasma treatment.

[0076] The wiring layer 19 embedded in the recess 13 of the substrate W is not limited to Ru, but can also be made of metals such as W, Mo, and Cr (chromium).

[0077] Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The above embodiments may be omitted, substituted, modified, and combined in various ways without departing from the appended claims and their spirit.

[0078] (Evaluation Test)

[0079] The following describes the evaluation tests conducted on a series of treatments related to this disclosure.

[0080] (Evaluation Experiment 1)

[0081] As evaluation experiment 1, the difference in the adsorption capacity of SiH4 gas for Ti and SiN films was confirmed. For two bare wafers serving as two silicon substrates, a Ti film was deposited on one and a SiN film on the other. In a processing container, each wafer was heated to 400°C, and SiH4 gas was supplied at a flow rate of 500 sccm. Each wafer was then exposed to a vacuum atmosphere of 133 Pa (1 torr) for 150 seconds. SEM analysis was performed on each bare wafer after this SiH4 gas supply to confirm the presence or absence of the Si film.

[0082] Figure 10 , Figure 11 This shows SEM images of the surface layer of each bare wafer after this evaluation test. Figure 10 This is a SEM image of a bare wafer with a Ti film deposited before SiH4 gas supply. Figure 11 These are SEM images of a bare wafer with a SiN film. As shown in these images, the Ti film becomes a TiSi film through the above experiments, and a Si film is formed on the TiSi film. Furthermore, no Si film is formed on the SiN film. This confirms that SiH4 gas is difficult to adsorb onto the SiN film, but readily adsorbs onto Ti-containing films such as the Ti film, and readily forms a Si film.

[0083] <Evaluation Experiment 2>

[0084] As an evaluation test 2, the difference in the expansion caused by the erosion of the Si layer by the TiSi film 15 based on the timing of supplying SiH4 gas to the Ti film 14 was confirmed. Figure 12 This is a longitudinal cross-sectional view showing the surface changes of the substrate before and after evaluation test 2. First, multiple bare wafers serving as silicon substrates were prepared. For each bare wafer, after a SiGe (germanium) layer and a Si layer were deposited on the surface via CVD, the thickness of the Si layer exposed on the surface was measured. Next, as... Figures 4A to 5C , Figure 9 These bare wafers were subjected to gas treatment as shown. The temperature of the bare wafers during treatment was set to 450°C. The SiH4 gas supply to each bare wafer was... Figure 13 The different timings shown. More specifically, Figure 9 The time intervals t1 to t4 in the diagram are the same across all bare wafers, but the timing of supplying SiH4 gas at the beginning of time t2 is staggered across the bare wafers, making the lengths between time intervals t1 and t2 different for each wafer.

[0085] After the above series of processes, the length between each interface between the TiSi film and the SiGe layer formed on each bare wafer is measured, thereby determining the thickness of the Si layer remaining on each bare wafer. Furthermore, the difference between the thickness of the residual Si layer in each bare wafer and the thickness of the Si layer measured before the series of processes is calculated as the amount of Si layer consumed.

[0086] Figure 13 This is a graph showing the results of evaluation experiment 2. The horizontal axis represents the start time of SiH4 gas supply (the length of time t1~t2), and the vertical axis represents the amount of Si layer consumed. As shown in the graph, when the start time of SiH4 gas supply is set to 0 seconds, the amount of Si consumed in the bare wafer is the highest, at 4.7 nm. Moreover, as the start time of SiH4 gas supply increases, the amount of Si consumed gradually decreases and then increases, after which it becomes approximately constant. The amount of Si consumed is the lowest, zero, when the start time of SiH4 gas supply is 15 seconds.

[0087] When the SiH4 gas supply start time is zero or close to zero, Si consumption is relatively high. This is presumably because the adsorption of SiH4 gas onto the Si layer of the bare wafer is low, and the formation of the TiSi film 15 mostly utilizes Si derived from the Si layer. Regarding the decrease in Si consumption as the SiH4 gas supply start time increases within the range of less than 15 seconds, this is presumably because the increased deposition of Ti onto the Si layer forms a Ti film, which enhances the adsorption of SiH4 onto the bare wafer, and the Si derived from this SiH4 is used for the formation of the TiSi film 15.

[0088] Furthermore, regarding the fact that within a range where the SiH4 gas supply start time is longer than 15 seconds, the Si consumption increases with the increase of the SiH4 gas supply start time and then remains approximately constant, this indicates that the Si layer of the bare wafer has already been used for the formation of the TiSi film 15 before the SiH4 gas is supplied. Additionally, it shows that before the amount of Ti on the Si layer reaches a certain constant amount, the diffusion of Ti onto the Si layer increases as the amount of Ti increases. While a longer SiH4 gas supply start time leads to increased Si consumption, as shown in the graph, it is clear that Si consumption can be relatively suppressed within a range where the SiH4 gas supply start time is 30 seconds or less. Therefore, a SiH4 gas supply start time of 30 seconds or less is preferred.

[0089] The above experiments, conducted in other processing modules and under different processing conditions, confirmed the same variation in Si layer consumption as described above. Therefore, it can be concluded that by slightly delaying the supply of film-forming gas after the start of Ti film formation, SiH4 can be adsorbed onto the Ti film during the growth process, thereby supplying Si to the Ti film.

[0090] Explanation of reference numerals in the attached figures

[0091] W: Substrate; 11: Si layer; 14, 17: Ti film; 15: TiSi film.

Claims

1. A substrate processing method, comprising the following steps: A first metal film composed of a metal other than Ru is formed in the Si-containing layer exposed on the surface of the substrate; and Si element is supplied to the substrate, and a metal silicide film is formed from the Si element and the first metal film.

2. The substrate processing method according to claim 1, wherein, The Si-containing layer is the Si layer that forms the bottom surface of the recess formed on the substrate. The Si element is supplied to the first metal film in the form of a gaseous compound containing the Si element. The sidewalls of the recess are made of a compound containing Si. The substrate processing method includes an embedding step in which a second metal film is embedded in the recess in a manner that is stacked on the metal silicide film.

3. The substrate processing method according to claim 2, wherein, The metals constituting the first metal film, other than Ru, are any one of Ti, W, Mo, and Zr.

4. The substrate processing method according to claim 3, wherein, The metal that constitutes the first metal film, excluding Ru, is Ti.

5. The substrate processing method according to claim 2, wherein, The sidewalls of the recess are made of silicon nitride film.

6. The substrate processing method according to claim 5, wherein, The gas that is a compound containing the element Si is SiH4 gas.

7. The substrate processing method according to claim 2, wherein, The process for forming the first metal film is performed multiple times. Between the step of forming the first metal film and the subsequent step of forming the first metal film, a step of supplying the Si element to the substrate is performed, and the metal silicide film is formed from each of the first metal films.

8. A substrate processing apparatus comprising: A metal film forming section for forming a first metal film composed of a metal other than Ru in a Si-containing layer exposed on the surface of a substrate; and A metal silicide film forming section supplies Si element to the first metal film, and forms a metal silicide film from the Si element and the first metal film.

Images