Film deposition method and treatment system

Abstract

To provide a technique capable of suppressing diffusion of impurities from a substrate to a metal silicide film.SOLUTION: A film deposition method according to an embodiment of the invention has the steps of: (a) preparing a substrate in which a doped region including silicon to which impurities are added is formed on a surface; (b) forming a diffusion prevention layer including the impurities on the doped region; and (c) forming a metal film on the doped region in which the diffusion prevention layer is formed and forming a metal silicide film by reaction of the metal film and silicon in the doped region. The step (b) includes supplying an impurity containing gas containing the impurities to the substrate without causing plasmatization.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to deposition methods and processing systems. [Background technology]

[0002] There is known a technique in which a titanium-containing gas is supplied to a silicon wafer, plasma is generated to form a titanium film, and a titanium silicide film is formed by reaction between the titanium film and silicon of the silicon wafer (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-158828 A [Patent Document 2] JP 2003-203976 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique capable of suppressing the diffusion of impurities from a substrate to a metal silicide film. [Means for solving the problem]

[0005] A film formation method according to one embodiment of the present disclosure includes the steps of: (a) preparing a substrate having a doped region formed on a surface thereof, the doped region including silicon having an impurity added thereto; (b) forming a diffusion prevention layer including the impurity on the doped region; and (c) forming a metal film on the doped region including the diffusion prevention layer, and forming a metal silicide film by reacting the metal film with silicon in the doped region, the step (b) including supplying an impurity-containing gas including the impurity to the substrate without generating a plasma. Effect of the Invention

[0006] According to the present disclosure, it is possible to suppress the diffusion of impurities from a substrate to a metal silicide film. [Brief description of the drawings]

[0007] [Figure 1] 4 is a flowchart showing a film forming method according to a first example of the embodiment. [Diagram 2] 1A to 1C are cross-sectional views illustrating a film forming method according to a first example of an embodiment. [Diagram 3] 10 is a flowchart showing a film forming method according to a second example of the embodiment. [Figure 4] 5A to 5C are cross-sectional views showing a film forming method according to a second example of the embodiment. [Diagram 5] 10 is a flowchart showing a film forming method according to a third example of the embodiment. [Figure 6] 11 is a flowchart showing a film forming method according to a fourth example of the embodiment. [Figure 7] FIG. 1 illustrates an example of a processing system according to an embodiment. [Figure 8] FIG. 2 illustrates an example of a processing apparatus according to an embodiment. [Figure 9] FIG. 4 is a diagram showing the measurement results of contact resistance in Example 1. [Figure 10] FIG. 11 is a diagram showing the measurement results of contact resistance in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all of the accompanying drawings, the same or corresponding members or parts are designated by the same or corresponding reference numerals, and duplicated descriptions will be omitted.

[0009] [Film formation method] A film forming method according to an embodiment will be described. The film forming method according to the embodiment includes forming a diffusion prevention layer containing the same impurity as the doped region on a doped region before forming a metal silicide film on the doped region containing silicon (Si) to which an impurity is added. Hereinafter, a case where the impurity is boron (B) and the metal silicide film is a titanium silicide (TiSi) film will be described as an example.

[0010] (Example 1) A film forming method according to a first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a flowchart showing the film forming method according to the first embodiment. Figure 2 is a cross-sectional view showing the film forming method according to the first embodiment.

[0011] The film formation method according to the first example of the embodiment includes forming a boron adsorption layer 140 as a diffusion prevention layer. As shown in Fig. 1, the film formation method according to the first example of the embodiment includes a preparation step S11, an oxide film removal step S12, a boron adsorption layer formation step S13, and a titanium silicide film formation step S14.

[0012] The preparation step S11 includes preparing a substrate 100 as shown in FIG. 2(a). The substrate 100 includes a silicon single crystal substrate 110 and a silicon epitaxial layer 120 on the silicon single crystal substrate 110. The silicon epitaxial layer 120 has a doped region 121 to which boron is added. The doped region 121 constitutes the surface of the silicon epitaxial layer 120. The doped region 121 is, for example, a region exposed from a contact hole formed in an insulating film. A native oxide film 130 may be present on the surface of the doped region 121.

[0013] The oxide film removal step S12 is performed after the preparation step S11. As shown in FIG. 2(b), the oxide film removal step S12 includes removing the native oxide film 130 on the surface of the doped region 121. The oxide film removal step S12 includes, for example, a COR (Chemical Oxide Removal) process and a PHT (Post Heat Treatment) process. The COR process is a process in which a gas containing a halogen element and a basic gas are supplied to the substrate 100 as a process gas, so that the native oxide film 130 on the surface of the doped region 121 and the process gas react chemically with each other to generate a reaction product. The gas containing a halogen element is, for example, hydrogen fluoride (HF) gas. The basic gas is, for example, ammonia (NH3) gas. In this case, a reaction product containing mainly ammonium silicofluoride [(NH4)2SiF6] and water (H2O) is generated. The PHT process is a process in which the reaction product generated by the COR process is heated and the reaction product such as ammonium silicofluoride is sublimated. The oxide film removing step S12 is not limited to a step including the COR treatment and the PHT treatment. For example, the oxide film removing step S12 does not have to include the PHT treatment. If there is no native oxide film 130 on the surface of the doped region 121, the oxide film removing step S12 may be omitted.

[0014] The boron adsorption layer forming step S13 is performed after the oxide film removing step S12. The boron adsorption layer forming step S13 includes forming a boron adsorption layer 140 on the doped region 121 by supplying diborane (B2H6) gas to the substrate 100 without plasma, as shown in FIG. 2(c). The boron adsorption layer forming step S13 may be performed in a state where a metal-containing gas is not supplied to the substrate 100. The diborane gas is, for example, continuously supplied to the substrate 100. The diborane gas may be intermittently supplied to the substrate 100. The boron adsorption layer forming step S13 may include supplying a carrier gas together with the diborane gas to the substrate 100. The carrier gas is, for example, an inert gas such as nitrogen (N2) gas or argon (Ar). The boron adsorption layer forming step S13 includes maintaining the substrate 100 at a first temperature. The first temperature is, for example, 150° C. or higher. In this case, boron is easily adsorbed onto the doped region 121. The first temperature is, for example, a temperature lower than the temperature at which diborane gas self-decomposes. In this case, the self-decomposition of diborane gas is suppressed, and deposition of boron at various locations in the processing vessel is suppressed. As a result, generation of particles can be suppressed. The temperature at which diborane gas self-decomposes is about 300°C.

[0015] The titanium silicide film forming step S14 is performed after the boron adsorption layer forming step S13. As shown in FIG. 2(d), the titanium silicide film forming step S14 includes forming a titanium (Ti) film on the doped region 121 on which the boron adsorption layer 140 is formed, and forming a titanium silicide film 150 by reacting the titanium film with silicon in the doped region 121. The titanium silicide film forming step S14 includes forming a titanium film on the doped region 121 by exposing the substrate 100 to plasma generated from titanium tetrachloride (TiCl4) gas and a reducing gas. The titanium silicide film forming step S14 may include forming a titanium film on the doped region 121 by alternately repeating supplying titanium tetrachloride gas to the substrate 100 and supplying a reducing gas to the substrate 100 in the form of plasma. The titanium silicide film forming step S14 may include forming a titanium film on the doped region 121 by simultaneously supplying titanium tetrachloride gas to the substrate 100 and supplying a reducing gas in the form of plasma to the substrate 100. The titanium film reacts with silicon in the doped region 121 to form a titanium silicide film 150. The reducing gas is, for example, hydrogen (H2) gas. The titanium silicide film forming step S14 includes maintaining the substrate 100 at a second temperature. The second temperature is, for example, a temperature higher than the first temperature. The second temperature is, for example, 380° C. or higher and 450° C. or lower. By forming the titanium film at the second temperature, the titanium silicide film 150 can be formed by a thermal reaction with the silicon in the doped region 121 while the titanium film is being formed.

[0016] According to the film forming method according to the first example of the embodiment described above, before forming the titanium silicide film 150 on the doped region 121, the boron adsorption layer 140 is formed on the doped region 121. In this case, when forming the titanium silicide film 150, boron in the boron adsorption layer 140 is more likely to diffuse into the titanium silicide film 150 than boron in the doped region 121. Therefore, the diffusion of boron from the doped region 121 to the titanium silicide film 150 is suppressed, and the doped region 121 can be maintained at a high boron concentration. As a result, an increase in the contact resistance between the doped region 121 and the titanium silicide film 150 is suppressed, and a low contact resistance can be achieved.

[0017] According to the film formation method of the first embodiment, the boron adsorption layer 140 is formed as the diffusion prevention layer. In this case, it is possible to suppress the incorporation of elements other than boron into the doped region 121 as impurities.

[0018] (Example 2) A film forming method according to a second example of the embodiment will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a flowchart showing the film forming method according to the second example of the embodiment. Fig. 4 is a cross-sectional view showing the film forming method according to the second example of the embodiment.

[0019] The film forming method according to the second example of the embodiment includes forming a TiB layer 160 as a diffusion barrier layer. As shown in Fig. 3, the film forming method according to the second example of the embodiment includes a preparation step S21, an oxide film removing step S22, a TiB layer forming step S23, and a titanium silicide film forming step S24.

[0020] 4(a), the preparation step S21 includes preparing a substrate 100. The preparation step S21 may be the same as the preparation step S11.

[0021] The oxide film removing step S22 is performed after the preparation step S21. As shown in Fig. 4(b), the oxide film removing step S22 includes removing the native oxide film 130 on the surface of the doped region 121. The oxide film removing step S22 may be the same as the oxide film removing step S12.

[0022] The TiB layer forming step S23 is performed after the oxide film removing step S22. The TiB layer forming step S23 includes forming a TiB layer 160 on the doped region 121 by supplying diborane gas and titanium tetrachloride gas to the substrate 100 as shown in FIG. 4(c). The TiB layer forming step S23 includes, for example, alternately repeating supplying diborane gas to the substrate 100 without plasma and supplying titanium tetrachloride gas to the substrate 100. In this case, the diborane gas may be supplied to the substrate 100 without plasma first. This makes it easier to suppress the chlorine (Cl) of the titanium tetrachloride gas from being taken in as an impurity to the doped region 121. The TiB layer forming step S23 may include simultaneously supplying diborane gas to the substrate 100 without plasma and supplying titanium tetrachloride gas to the substrate 100. The titanium tetrachloride gas may be supplied to the substrate 100 after being plasma, or may be supplied to the substrate 100 without being plasma. The TiB layer forming step S23 includes maintaining the substrate 100 at a third temperature. The third temperature is, for example, 200° C. or higher and 450° C. or lower.

[0023] The titanium silicide film forming step S24 is performed after the TiB layer forming step S23. As shown in Fig. 4(d), the titanium silicide film forming step S24 includes forming a titanium film on the doped region 121 in which the TiB layer 160 is formed, and forming a titanium silicide film 150 by a reaction between the titanium film and silicon in the doped region 121. The titanium silicide film forming step S24 may be the same as the titanium silicide film forming step S14.

[0024] According to the film forming method according to the second example of the embodiment described above, before forming the titanium silicide film 150 on the doped region 121, the TiB layer 160 is formed on the doped region 121. In this case, when forming the titanium silicide film 150, boron in the TiB layer 160 is more likely to diffuse into the titanium silicide film 150 than boron in the doped region 121. Therefore, the diffusion of boron from the doped region 121 to the titanium silicide film 150 is suppressed, and the doped region 121 can be maintained at a high boron concentration. As a result, an increase in the contact resistance between the doped region 121 and the titanium silicide film 150 is suppressed, and a low contact resistance can be achieved.

[0025] According to the film forming method of the second embodiment, the TiB layer 160 is formed as the diffusion prevention layer. In this case, the diffusion of boron from the doped region 121 to the titanium silicide film 150 can be effectively suppressed.

[0026] (Example 3) A film forming method according to a third example of the embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing a film forming method according to the third example of the embodiment.

[0027] The film formation method according to the third example of the embodiment includes forming, in this order, a boron adsorption layer 140 and a TiB layer 160 as diffusion prevention layers. As shown in Fig. 5, the film formation method according to the third example of the embodiment includes a preparation step S31, an oxide film removal step S32, a boron adsorption layer formation step S33, a TiB layer formation step S34, and a titanium silicide film formation step S35.

[0028] The preparation step S31 and the oxide film removing step S32 may be the same as the preparation step S11 and the oxide film removing step S12, respectively.

[0029] The boron adsorption layer forming step S33 is performed after the oxide film removing step S32. The boron adsorption layer forming step S33 may be the same as the boron adsorption layer forming step S13.

[0030] The TiB layer forming step S34 is performed after the boron adsorption layer forming step S33. The TiB layer forming step S34 may be the same as the TiB layer forming step S23.

[0031] The titanium silicide film forming step S35 is performed after the TiB layer forming step S34. The titanium silicide film forming step S35 may be the same as the titanium silicide film forming step S14.

[0032] According to the film forming method according to the third example of the embodiment described above, before forming the titanium silicide film 150 on the doped region 121, the boron adsorption layer 140 and the TiB layer 160 are formed in this order on the doped region 121. In this case, when forming the titanium silicide film 150, the boron of the boron adsorption layer 140 and the boron of the TiB layer 160 are more likely to diffuse into the titanium silicide film 150 than the boron of the doped region 121. Therefore, the diffusion of boron from the doped region 121 to the titanium silicide film 150 is suppressed, and the doped region 121 can be maintained at a high boron concentration. As a result, an increase in the contact resistance between the doped region 121 and the titanium silicide film 150 is suppressed, and a low contact resistance can be achieved.

[0033] According to the film formation method of the third embodiment, the boron adsorption layer 140 and the TiB layer 160 are formed in this order as the diffusion prevention layer. In this case, while preventing elements other than boron from being introduced as impurities into the doped region 121, the diffusion of boron from the doped region 121 to the titanium silicide film 150 can be effectively suppressed.

[0034] (Example 4) A film forming method according to a fourth example of the embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the film forming method according to the fourth example of the embodiment.

[0035] The film formation method according to the fourth example of the embodiment includes forming, in this order, a TiB layer 160 and a boron adsorption layer 140 as diffusion prevention layers. As shown in Fig. 6, the film formation method according to the fourth example of the embodiment includes a preparation step S41, an oxide film removal step S42, a TiB layer formation step S43, a boron adsorption layer formation step S44, and a titanium silicide film formation step S45.

[0036] The preparation step S41 and the oxide film removing step S42 may be the same as the preparation step S11 and the oxide film removing step S12, respectively.

[0037] The TiB layer forming step S43 is performed after the oxide film removing step S42. The TiB layer forming step S43 may be the same as the TiB layer forming step S23.

[0038] The boron adsorption layer forming step S44 is performed after the TiB layer forming step S43. The boron adsorption layer forming step S44 may be the same as the boron adsorption layer forming step S13.

[0039] The titanium silicide film forming step S45 is performed after the boron adsorption layer forming step S44. The titanium silicide film forming step S45 may be the same as the titanium silicide film forming step S14.

[0040] According to the film forming method according to the fourth example of the embodiment described above, before forming the titanium silicide film 150 on the doped region 121, the TiB layer 160 and the boron adsorption layer 140 are formed in this order on the doped region 121. In this case, when forming the titanium silicide film 150, the boron of the TiB layer 160 and the boron of the boron adsorption layer 140 are more likely to diffuse into the titanium silicide film 150 than the boron of the doped region 121. Therefore, the diffusion of boron from the doped region 121 to the titanium silicide film 150 is suppressed, and the doped region 121 can be maintained at a high boron concentration. As a result, the increase in the contact resistance between the doped region 121 and the titanium silicide film 150 is suppressed, and a low contact resistance can be achieved.

[0041] [Processing System] An example of a processing system PS capable of performing the film forming methods according to the first to fourth examples of the embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of a processing system PS according to the embodiment.

[0042] The processing system PS includes processing devices PM1 to PM4, a vacuum transfer chamber VTM, load lock chambers LL1 to LL3, an atmospheric transfer chamber LM, load ports LP1 to LP3, and a general control unit CU.

[0043] The processing devices PM1 to PM4 are connected to the vacuum transfer chamber VTM via gate valves G11 to G14, respectively. The processing devices PM1 to PM4 are each depressurized to a predetermined vacuum atmosphere. The processing devices PM1 to PM4 each perform a desired process on the substrate W therein. The processing device PM1 is a device that performs, for example, the COR process of the oxide film removal steps S12, S22, S32, and S42. The processing device PM2 is a device that performs, for example, the PHT process of the oxide film removal steps S12, S22, S32, and S42. The processing device PM3 is a device that performs, for example, the boron adsorption layer formation steps S13, S33, and S44 and the TiB layer formation steps S23, S34, and S43. The processing device PM4 is a device that performs, for example, the titanium silicide film formation steps S14, S24, S35, and S45.

[0044] The interior of the vacuum transfer chamber VTM is depressurized to a predetermined vacuum atmosphere. A transfer mechanism TR1 is provided inside the vacuum transfer chamber VTM. The transfer mechanism TR1 is configured to be able to transfer a substrate W under a reduced pressure state. The transfer mechanism TR1 transfers the substrate W to the processing devices PM1-PM4 and the load lock chambers LL1-LL3. The transfer mechanism TR1 has, for example, two forks FK11, FK12 that are independently movable. Each of the forks FK11, FK12 is configured to be able to hold a substrate W.

[0045] The load lock chambers LL1 to LL3 are connected to the vacuum transfer chamber VTM via gate valves G21 to G23, respectively. The load lock chambers LL1 to LL3 are connected to the atmospheric transfer chamber LM via gate valves G31 to G33, respectively. The interior of the load lock chambers LL1 to LL3 can be switched between an atmospheric atmosphere and a vacuum atmosphere.

[0046] The atmospheric transfer chamber LM has an atmospheric atmosphere inside. For example, a downflow of clean air is formed inside the atmospheric transfer chamber LM. An aligner AN is provided inside the atmospheric transfer chamber LM. The aligner AN aligns the substrate W. A transport mechanism TR2 is provided in the atmospheric transfer chamber LM. The transport mechanism TR2 transports the substrate W to the load lock chambers LL1 to LL3, the carriers C of the load ports LP1 to LP3, and the aligner AN.

[0047] The load ports LP1 to LP3 are provided on the long side walls of the atmospheric transfer chamber LM. A carrier C is attached to each of the load ports LP1 to LP3. The carrier C is, for example, a FOUP (Front Opening Unified Pod).

[0048] The overall control unit CU is, for example, a computer. The overall control unit CU includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an auxiliary storage device. The CPU operates based on programs stored in the ROM or the auxiliary storage device, and controls each part of the processing system PS. For example, the overall control unit CU executes operations of the processing devices PM1 to PM4, the transport mechanisms TR1 and TR2, the opening and closing of the gate valves G11 to G14, G21 to G23, and G31 to G33, switching of the atmosphere in the load lock chambers LL1 to LL3, etc.

[0049] [Operation of the Processing System] An example of the operation of the processing system PS according to the embodiment will be described with reference to Fig. 7. In the following, an example will be described in which the processing system PS performs a film formation method according to a first example of the embodiment. The same can be said for the cases in which the processing system PS performs the film formation methods according to the second to fourth examples of the embodiment. The operation of the processing system PS according to the embodiment is performed under the control of the overall control unit CU.

[0050] First, the carrier C is attached to the load port LP1 in a state in which it accommodates a plurality of substrates W. Each substrate W may be a substrate 100 having a doped region 121 formed on its surface.

[0051] Next, the transport mechanism TR2 transports the substrate W accommodated in the carrier C to the aligner AN. Next, the aligner AN aligns the substrate W. Next, the overall control unit CU switches the closed gate valve G31 to an open state. Next, the transport mechanism TR2 receives the substrate W from the aligner AN and transports it to the load lock chamber LL1, which has an atmospheric atmosphere. Next, the overall control unit CU switches the open gate valve G31 to a closed state. Next, the overall control unit CU switches the atmosphere inside the load lock chamber LL1 from the atmospheric atmosphere to a vacuum atmosphere.

[0052] Next, the overall control unit CU switches the gate valves G11 and G21 from the closed state to the open state. Next, the transport mechanism TR1 receives the substrate W from the load lock chamber LL1 and transports it to the processing device PM1. Next, the overall control unit CU switches the gate valves G11 and G21 from the open state to the closed state.

[0053] Next, the processing apparatus PM1 performs the COR process of the oxide film removal step S12, whereby the surface layer of the native oxide film 130 on the surface of the doped region 121 formed on the surface of the substrate W is transformed into a reaction product.

[0054] Next, the overall control unit CU switches the gate valves G11 and G12 from the closed state to the open state. Next, the transport mechanism TR1 receives the substrate W from the processing device PM1 and transports it to the processing device PM2. Next, the overall control unit CU switches the gate valves G11 and G12 from the open state to the closed state.

[0055] Next, the processing apparatus PM2 performs a PHT process in the oxide film removal step S12, whereby reaction products remaining on the surface of the substrate W are sublimated, and the native oxide film 130 on the surface of the doped region 121 is removed.

[0056] Next, the overall control unit CU switches the gate valves G12 and G13 from the closed state to the open state. Next, the transport mechanism TR1 receives the substrate W from the processing device PM2 and transports it to the processing device PM3. Next, the overall control unit CU switches the gate valves G12 and G13 from the open state to the closed state.

[0057] Next, the processing apparatus PM3 performs the boron adsorption layer forming step S13. As a result, the boron adsorption layer 140 is formed on the doped region 121.

[0058] Next, the overall control unit CU switches the gate valves G13 and G14 from the closed state to the open state. Next, the transport mechanism TR1 receives the substrate W from the processing device PM3 and transports it to the processing device PM4. Next, the overall control unit CU switches the gate valves G13 and G14 from the open state to the closed state.

[0059] Next, the processing apparatus PM4 performs a titanium silicide film formation step S14. As a result, a titanium film is formed on the doped region 121 on which the boron adsorption layer 140 has been formed. The titanium film reacts with silicon in the doped region 121 to form a titanium silicide film 150.

[0060] Next, the overall control unit CU switches the gate valves G14 and G23 from the closed state to the open state. Next, the transfer mechanism TR1 receives the substrate from the processing device PM4 and transfers it to the load lock chamber LL3 in a vacuum atmosphere. Next, the overall control unit CU switches the gate valves G14 and G23 from the open state to the closed state. Next, the overall control unit CU switches the atmosphere in the load lock chamber LL3 from a vacuum atmosphere to an air atmosphere.

[0061] Next, the general control unit CU switches the gate valve G33, which is closed, to an open state. Next, the transport mechanism TR2 receives the substrate W from the load lock chamber LL3, transports it to the carrier C attached to the load port LP3, and stores the substrate W in the carrier C. This completes the processing of one substrate W.

[0062] In the above-described operation of the processing system PS, the substrate W is transferred from the atmospheric transfer chamber LM to the vacuum transfer chamber VTM via the load lock chamber LL1, and then transferred from the vacuum transfer chamber VTM to the atmospheric transfer chamber LM via the load lock chamber LL3. However, the transfer route of the substrate W is not limited to this. The substrate W may be transferred from the atmospheric transfer chamber LM to the vacuum transfer chamber VTM via any of the load lock chambers LL1 to LL3. The substrate W may be transferred from the vacuum transfer chamber VTM to the atmospheric transfer chamber LM via any of the load lock chambers LL1 to LL3.

[0063] [Processing Device] An example of the processing apparatus PM3 will be described with reference to Fig. 8. Fig. 8 is a diagram showing an example of the processing apparatus PM3. The processing apparatus PM3 is configured to be able to perform the boron adsorption layer forming steps S13, S33, and S44 and the TiB layer forming steps S23, S34, and S43.

[0064] As shown in FIG. 8, the processing apparatus PM3 includes a processing vessel 1, a mounting table 2, a shower head 3, an exhaust unit 4, a gas supply mechanism 5, an RF power supply unit 8, and a control unit 9.

[0065] The processing vessel 1 is made of a metal such as aluminum and has a substantially cylindrical shape. The processing vessel 1 accommodates a substrate W. A loading / unloading port 11 is provided on a side wall of the processing vessel 1 for loading or unloading the substrate W. The loading / unloading port 11 is opened and closed by a gate valve 12. An annular exhaust duct 13 having a rectangular cross section is provided on the main body of the processing vessel 1. A slit 13a is formed along the inner peripheral surface of the exhaust duct 13. An exhaust port 13b is formed on the outer wall of the exhaust duct 13. A top wall 14 is provided on the upper surface of the exhaust duct 13 so as to close the upper opening of the processing vessel 1 via an insulating member 16. A seal ring 15 hermetically seals the gap between the exhaust duct 13 and the insulating member 16. The partition member 17 partitions the inside of the processing vessel 1 into upper and lower sections when the mounting table 2 and the cover member 22 are raised to a processing position described later.

[0066] The mounting table 2 horizontally supports the substrate W in the processing chamber 1. The mounting table 2 is formed in a disk shape slightly larger than the substrate W. The mounting table 2 is made of a ceramic material such as AlN, or a metal material such as an aluminum or nickel alloy. A heater 21 for heating the substrate W is embedded inside the mounting table 2. The heater 21 generates heat when powered by a heater power supply (not shown). The output of the heater 21 is controlled by a temperature signal from a thermocouple (not shown) provided near the upper surface of the mounting table 2, thereby controlling the substrate W to a predetermined temperature. A cover member 22 is provided on the mounting table 2 so as to cover the outer circumferential region of the upper surface and the side surfaces. The cover member 22 is made of ceramics such as alumina.

[0067] A support member 23 is connected to the bottom surface of the mounting table 2. The support member 23 supports the mounting table 2. The support member 23 extends from the center of the bottom surface of the mounting table 2 through a hole formed in the bottom wall of the processing vessel 1 to below the processing vessel 1, and its lower end is connected to the lifting mechanism 24. The mounting table 2 is raised and lowered via the support member 23 by the lifting mechanism 24. The mounting table 2 is raised and lowered between a processing position shown by a solid line in FIG. 8 and a transport position shown by a two-dot chain line below the processing position. The processing position is a position where the substrate W is processed. The transport position is a position where the substrate W is transported in or out. A flange 25 is attached to the lower side of the processing vessel 1 of the support member 23. A bellows 26 is provided between the bottom surface of the processing vessel 1 and the flange 25. The bellows 26 separates the atmosphere inside the processing vessel 1 from the outside air, and expands and contracts with the raising and lowering operation of the mounting table 2.

[0068] Three lift pins 27 (only two are shown) are provided near the bottom surface of the processing vessel 1. The lift pins 27 protrude upward from a lift plate 27a. The lift pins 27 are raised and lowered via the lift plate 27a by a lift mechanism 28 provided below the processing vessel 1. The lift pins 27 are inserted into through holes 2a provided in the mounting table 2 at the transfer position, and can be protruded and retracted from the upper surface of the mounting table 2. The substrate W is transferred between the transfer mechanism (not shown) and the mounting table 2 by raising and lowering the lift pins 27.

[0069] The shower head 3 supplies a processing gas into the processing vessel 1 in a shower-like manner. The shower head 3 is made of metal. The shower head 3 is provided to face the mounting table 2. The shower head 3 has approximately the same diameter as the mounting table 2. The shower head 3 has a main body 31 fixed to the ceiling wall 14 of the processing vessel 1 and a shower plate 32 connected below the main body 31. A gas diffusion space 33 is formed between the main body 31 and the shower plate 32. A gas introduction hole 36 is provided in the gas diffusion space 33 so as to penetrate the center of the ceiling wall 14 and the main body 31 of the processing vessel 1. An annular protrusion 34 protruding downward is formed on the periphery of the shower plate 32. A plurality of gas discharge holes 35 are formed on the inner flat surface of the annular protrusion 34. When the mounting table 2 is in the processing position, a processing space 38 is formed between the mounting table 2 and the shower plate 32, and the upper surface of the cover member 22 and the annular protrusion 34 are close to each other to form an annular gap 39.

[0070] The exhaust unit 4 exhausts the inside of the processing vessel 1. The exhaust unit 4 has an exhaust pipe 41 and an exhaust mechanism 42. The exhaust pipe 41 is connected to the exhaust port 13b. The exhaust mechanism 42 has a vacuum pump, a pressure control valve, etc., connected to the exhaust pipe 41. During processing, gas inside the processing vessel 1 reaches the exhaust duct 13 through the slit 13a, and is exhausted by the exhaust mechanism 42 from the exhaust duct 13 through the exhaust pipe 41.

[0071] The gas supply mechanism 5 supplies a processing gas into the processing chamber 1. The gas supply mechanism 5 includes a titanium-containing gas supply source 51a, a boron-containing gas supply source 52a, an Ar gas supply source 53a, and an Ar gas supply source 54a.

[0072] The titanium-containing gas supply source 51a supplies a titanium-containing gas into the processing vessel 1 through the gas supply line 51b. The titanium-containing gas is used when forming the TiB layer 160. In this embodiment, the titanium-containing gas is titanium tetrachloride gas. In the gas supply line 51b, a flow rate controller 51c, a storage tank 51d, and a valve 51e are interposed from the upstream side. The downstream side of the valve 51e of the gas supply line 51b is connected to the gas inlet 36 through a gas supply line 56. The titanium-containing gas supplied from the titanium-containing gas supply source 51a is temporarily stored in the storage tank 51d before being supplied into the processing vessel 1, and is then pressurized to a predetermined pressure in the storage tank 51d before being supplied into the processing vessel 1. The supply and stop of the titanium-containing gas from the storage tank 51d to the processing vessel 1 is performed by opening and closing the valve 51e. By temporarily storing the titanium-containing gas in the storage tank 51d, a relatively large flow rate of the titanium-containing gas can be stably supplied into the processing vessel 1.

[0073] The boron-containing gas supply source 52a supplies a boron-containing gas into the processing vessel 1 through a gas supply line 52b. The boron-containing gas is used when forming the boron adsorption layer 140 and the TiB layer 160. In this embodiment, the boron-containing gas is diborane gas. In the gas supply line 52b, a flow rate controller 52c, a storage tank 52d, and a valve 52e are interposed from the upstream side. The downstream side of the valve 52e of the gas supply line 52b is connected to the gas inlet 36 through a gas supply line 56. The boron-containing gas supplied from the boron-containing gas supply source 52a is temporarily stored in the storage tank 52d before being supplied into the processing vessel 1, and is then pressurized to a predetermined pressure in the storage tank 52d before being supplied into the processing vessel 1. The supply and stop of the boron-containing gas from the storage tank 52d to the processing vessel 1 is performed by opening and closing the valve 52e. By temporarily storing the boron-containing gas in the storage tank 52d, the boron-containing gas can be stably supplied into the processing vessel 1 at a relatively large flow rate.

[0074] The Ar gas supply source 53a supplies Ar gas as an inert gas into the processing vessel 1 via a gas supply line 53b. A flow rate controller 53c and a valve 53e are provided in the gas supply line 53b from the upstream side. The downstream side of the valve 53e of the gas supply line 53b is connected to a gas supply line 51b. The Ar gas supplied from the Ar gas supply source 53a is supplied into the processing vessel 1. The supply of Ar gas to the processing vessel 1 is started and stopped by opening and closing the valve 53e.

[0075] The Ar gas supply source 54a supplies Ar gas as an inert gas into the processing vessel 1 through a gas supply line 54b. A flow rate controller 54c and a valve 54e are provided in the gas supply line 54b from the upstream side. The downstream side of the valve 54e of the gas supply line 54b is connected to a gas supply line 52b. The Ar gas supplied from the Ar gas supply source 54a is supplied into the processing vessel 1. The supply of Ar gas to the processing vessel 1 is started and stopped by opening and closing the valve 54e.

[0076] The processing apparatus PM3 is a capacitively coupled plasma apparatus in which the mounting table 2 serves as a lower electrode and the shower head 3 serves as an upper electrode. The mounting table 2 serving as the lower electrode is grounded via a capacitor (not shown).

[0077] A high frequency power (hereinafter, also referred to as "RF power") is applied to the shower head 3 serving as the upper electrode by an RF power supply unit 8. The RF power supply unit 8 has a power feed line 81, a matching box 82, and a high frequency power supply 83. The high frequency power supply 83 is a power supply that generates high frequency power. The high frequency power has a frequency suitable for generating plasma. The frequency of the high frequency power is, for example, a frequency within a range of 450 KHz to 100 MHz. The high frequency power supply 83 is connected to the main body 31 of the shower head 3 via the matching box 82 and the power feed line 81. The matching box 82 has a circuit for matching the output reactance of the high frequency power supply 83 with the reactance of the load (upper electrode). The RF power supply unit 8 has been described as applying high frequency power to the shower head 3 serving as the upper electrode, but is not limited thereto. It may be configured to apply high frequency power to the mounting table 2 serving as the lower electrode.

[0078] The control unit 9 is, for example, a computer. The control unit 9 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an auxiliary storage device, etc. The CPU operates based on a program stored in the ROM or the auxiliary storage device, and controls the operation of the processing device PM3. The control unit 9 may be provided inside the processing device PM3, or may be provided externally. When the control unit 9 is provided externally to the processing device PM3, the control unit 9 controls the processing device PM3 via a communication means such as a wired or wireless communication means.

[0079] [Operation of the Processing Device] 8, as an example of the operation of the processing apparatus PM3, a case will be described in which the processing apparatus PM3 performs the boron adsorption layer forming step S13 on a substrate W. The substrate W may be a substrate 100 having a doped region 121 formed on its surface.

[0080] First, the control unit 9 opens the gate valve 12, and causes the transfer mechanism (not shown) to transfer the substrate 100 into the processing vessel 1 and place it on the mounting table 2. The control unit 9 moves the transfer mechanism out of the processing vessel 1, and then closes the gate valve 12. Next, the control unit 9 heats the substrate 100 to a predetermined temperature using the heater 21 of the mounting table 2, and adjusts the inside of the processing vessel 1 to a predetermined pressure using the exhaust mechanism 42. The predetermined temperature and the predetermined pressure may be the temperature and pressure, respectively, when the boron adsorption layer formation step S13 is performed.

[0081] Next, the control unit 9 controls each part of the processing device PM3 to perform the boron adsorption layer forming step S13. Specifically, the control unit 9 switches the valve 52e from a closed state to an open state. This causes diborane gas to be supplied to the substrate 100, and the boron adsorption layer 140 is formed on the doped region 121. After a predetermined time has elapsed, the control unit 9 switches the valve 52e from an open state to a closed state.

[0082] Next, the control unit 9 unloads the substrate 100 from the processing vessel 1 in the reverse order to the procedure for loading the substrate 100 into the processing vessel 1. With the above, the processing of one substrate 100 is completed.

[0083] 8, as another example of the operation of the processing apparatus PM3, a case will be described in which the processing apparatus PM3 performs a TiB layer forming step S23 on a substrate W. The substrate W may be a substrate 100 having a doped region 121 formed on its surface.

[0084] First, the control unit 9 opens the gate valve 12 and causes a transfer mechanism (not shown) to transfer the substrate 100 into the processing vessel 1 and place it on the mounting table 2. The substrate 100 may be a substrate 100 having a doped region 121 formed on its surface. The control unit 9 closes the gate valve 12 after retracting the transfer mechanism from inside the processing vessel 1. Next, the control unit 9 heats the substrate 100 to a predetermined temperature using the heater 21 of the mounting table 2, and adjusts the inside of the processing vessel 1 to a predetermined pressure using the exhaust mechanism 42. The predetermined temperature and the predetermined pressure may be the temperature and pressure when the TiB layer formation step S23 is performed, respectively.

[0085] Next, the control unit 9 controls each part of the processing device PM3 to perform the TiB layer forming step S23. Specifically, the control unit 9 switches the valve 52e in a closed state to an open state. As a result, diborane gas is supplied to the substrate 100, and the diborane gas is adsorbed on the doped region 121. After a predetermined time has passed, the control unit 9 switches the valve 52e in an open state to a closed state. Then, the control unit 9 switches the valve 51e in a closed state to an open state. As a result, titanium tetrachloride gas is supplied to the substrate 100, and the titanium tetrachloride gas is adsorbed on the doped region 121. After a predetermined time has passed, the control unit 9 switches the valve 51e in an open state to a closed state. The control unit 9 alternately repeats the switching of the valve 52e and the switching of the valve 51e. As a result, the TiB layer 160 is formed on the doped region 121.

[0086] Next, the control unit 9 unloads the substrate 100 from the processing vessel 1 in the reverse order to the procedure for loading the substrate 100 into the processing vessel 1. With the above, the processing of one substrate 100 is completed.

[0087] Example 1 In Example 1, the contact resistance between the doped region 121 and the titanium silicide film 150 was compared between the case where the boron adsorption layer 140 was formed on the doped region 121 before the titanium silicide film 150 was formed on the doped region 121 and the case where it was not formed. In Example 1, evaluation was performed on three recesses R1, R2, and R3 with different CD (Critical Dimension) sizes. The same conditions were set between the case where the boron adsorption layer 140 was formed and the case where it was not formed, except for the presence or absence of the boron adsorption layer 140. In Example 1, the temperature of the substrate 100 when the boron adsorption layer 140 was formed was set to 200° C., and the temperature of the substrate 100 when the titanium silicide film 150 was formed was set to 450° C.

[0088] Fig. 9 is a diagram showing the measurement results of the contact resistance in Example 1. The bar graphs on the left, center, and right in Fig. 9 respectively show the results of comparing the contact resistance in the case where the boron adsorption layer 140 is formed (solid black) on the doped region 121 and the case where it is not formed (open white) for the recesses R1, R2, and R3.

[0089] As shown in FIG. 9, in the recess R1, it is found that the contact resistance when the boron adsorption layer 140 is formed on the doped region 121 is 27.7% lower than the contact resistance when the boron adsorption layer 140 is not formed on the doped region 121. In the recess R2, it is found that the contact resistance when the boron adsorption layer 140 is formed on the doped region 121 is 24.7% lower than the contact resistance when the boron adsorption layer 140 is not formed on the doped region 121. In the recess R3, it is found that the contact resistance when the boron adsorption layer 140 is formed on the doped region 121 is 23.8% lower than the contact resistance when the boron adsorption layer 140 is not formed on the doped region 121. These results show that a low contact resistance can be achieved by forming the boron adsorption layer 140 on the doped region 121 before forming the titanium silicide film 150 on the doped region 121.

[0090] Example 2 In Example 2, instead of forming the titanium silicide film 150 on the doped region 121, a molybdenum silicide film was formed on the doped region 121. In Example 2, the contact resistance between the doped region 121 and the molybdenum silicide film was compared between the case where the boron adsorption layer 140 was formed on the doped region 121 before the molybdenum silicide film was formed on the doped region 121 and the case where it was not formed. In Example 2, evaluation was performed on three recesses R1, R2, and R3 with different CD sizes. The same conditions were set for the case where the boron adsorption layer 140 was formed and the case where it was not formed, except for the presence or absence of the formation of the boron adsorption layer 140. In Example 2, the temperature of the substrate 100 when the boron adsorption layer 140 was formed was set to 300° C., and the temperature of the substrate 100 when the molybdenum silicide film was formed was set to 400° C. In addition, molybdenum pentachloride gas was used as the molybdenum-containing gas when the molybdenum silicide film was formed.

[0091] Fig. 10 is a diagram showing the measurement results of the contact resistance in Example 2. The bar graphs on the left, center, and right in Fig. 10 respectively show the results of comparing the contact resistance in the case where the boron adsorption layer 140 is formed on the doped region 121 (solid black) and the case where it is not formed (open white) for the recesses R1, R2, and R3.

[0092] As shown in FIG. 10, in the recess R1, it is found that the contact resistance when the boron adsorption layer 140 is formed on the doped region 121 is 49.4% lower than the contact resistance when the boron adsorption layer 140 is not formed on the doped region 121. In the recess R2, it is found that the contact resistance when the boron adsorption layer 140 is formed on the doped region 121 is 44.9% lower than the contact resistance when the boron adsorption layer 140 is not formed on the doped region 121. In the recess R3, it is found that the contact resistance when the boron adsorption layer 140 is formed on the doped region 121 is 42.0% lower than the contact resistance when the boron adsorption layer 140 is not formed on the doped region 121. These results show that a low contact resistance can be achieved by forming the boron adsorption layer 140 on the doped region 121 before forming a molybdenum silicide film on the doped region 121.

[0093] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0094] In the above embodiment, the case where the impurity is boron and the impurity-containing gas is diborane gas has been described, but the present disclosure is not limited thereto. For example, the impurity-containing gas may be another boron-containing gas such as boron trichloride (BCl3) gas. For example, the impurity may be a p-type impurity other than boron, and the impurity-containing gas may be a gas containing the p-type impurity. For example, the impurity may be phosphorus (P), and the impurity-containing gas may be a phosphorus-containing gas such as phosphine (PH3) gas. For example, the impurity may be an n-type impurity other than phosphorus, and the impurity-containing gas may be a gas containing the n-type impurity.

[0095] In the above embodiment, the first metal-containing gas is titanium tetrachloride gas, but the present disclosure is not limited thereto. For example, the first metal-containing gas may be another titanium-containing gas such as titanium bromide (TiBr4) gas, dimethylamino titanium (TDMAT) gas, diethylamino titanium (TDEAT). For example, the first metal-containing gas may be a molybdenum-containing gas. The molybdenum-containing gas may be a molybdenum halide gas, a molybdenum oxyhalide gas, or the like. The halogen is fluorine, chlorine, bromine, or iodine. For example, the first metal-containing gas may be a metal-containing gas containing at least one metal selected from the group consisting of titanium, nickel (Ni), cobalt (Co), platinum (Pt), molybdenum (Mo), tantalum (Ta), hafnium (Hf), zirconium (Zr), ruthenium (Ru), niobium (Nb), antimony (Sb), and bismuth (Bi).

[0096] In the above embodiment, the second metal-containing gas is the same gas as the first metal-containing gas, but the present disclosure is not limited thereto. For example, the second metal-containing gas may be a gas different from the first metal-containing gas. For example, the second metal-containing gas may be any of the metal-containing gases exemplified as the first metal-containing gas.

[0097] In the above embodiment, the metal constituting the metal film is titanium, but the present disclosure is not limited thereto. For example, the metal constituting the metal film may be at least one selected from the group consisting of titanium, nickel, cobalt, platinum, molybdenum, tantalum, hafnium, zirconium, ruthenium, niobium, antimony, and bismuth. [Explanation of symbols]

[0098] 100 Substrates 121 Doped Region 140 Boron adsorption layer 150 Titanium silicide film 160 TiB layer S11, S21, S31, S41 Preparation process S13, S33, S44 Boron adsorption layer formation process S23, S34, S43 TiB layer formation process S14, S24, S35, S45 Titanium silicide film formation process

Claims

1. (a) providing a substrate having a doped region formed on a surface thereof, the doped region comprising silicon to which an impurity has been added; (b) forming a diffusion barrier layer containing the impurity on the doped region; (c) forming a metal film on the doped region on which the diffusion prevention layer is formed, and forming a metal silicide film by reaction between the metal film and silicon in the doped region; having The step (b) includes supplying an impurity-containing gas containing the impurity to the substrate without converting the gas into plasma. Film formation method.

2. The step (b) is carried out in a state where no metal-containing gas is supplied to the substrate. The film forming method according to claim 1 .

3. The step (b) includes continuously supplying the impurity-containing gas to the substrate; The film forming method according to claim 2 .

4. The step (b) includes intermittently supplying the impurity-containing gas to the substrate; The film forming method according to claim 2 .

5. The step (b) includes maintaining the substrate at a temperature lower than a temperature at which the impurity-containing gas self-decomposes. The film forming method according to claim 2 .

6. The step (b) includes supplying a first metal-containing gas to the substrate; The film forming method according to claim 1 .

7. The step (b) includes simultaneously supplying the impurity-containing gas to the substrate without generating plasma and supplying the first metal-containing gas to the substrate. The film forming method according to claim 6.

8. The step (b) includes alternately repeating supplying the impurity-containing gas to the substrate without generating plasma and supplying the first metal-containing gas to the substrate. The film forming method according to claim 6.

9. The impurity-containing gas is first supplied to the substrate without being turned into plasma. The film forming method according to claim 8.

10. The first metal-containing gas is supplied to the substrate without being turned into plasma. The film forming method according to claim 6.

11. The step (c) includes supplying a second metal-containing gas to the substrate; The second metal-containing gas is the same gas as the first metal-containing gas. The film forming method according to claim 6.

12. The step (b) a step of supplying the impurity-containing gas to the substrate without plasma, the step being performed in a state in which a metal-containing gas is not supplied to the substrate; alternately repeating supplying the impurity-containing gas to the substrate without generating plasma and supplying a first metal-containing gas to the substrate; Including, The film forming method according to claim 1 .

13. The step (b) a step of supplying the impurity-containing gas to the substrate without plasma, the step being performed in a state in which a metal-containing gas is not supplied to the substrate; supplying the impurity-containing gas to the substrate without generating a plasma and supplying a first metal-containing gas to the substrate simultaneously; Including, The film forming method according to claim 1 .

14. The first metal-containing gas contains at least one metal selected from the group consisting of titanium (Ti), nickel (Ni), cobalt (Co), platinum (Pt), molybdenum (Mo), tantalum (Ta), hafnium (Hf), zirconium (Zr), ruthenium (Ru), niobium (Nb), antimony (Sb), and bismuth (Bi); The film forming method according to claim 6 .

15. The first metal-containing gas is titanium tetrachloride gas or molybdenum pentachloride gas. The film forming method according to claim 6 .

16. The impurity is a p-type impurity. The film forming method according to claim 1 .

17. The p-type impurity is boron. The film forming method according to claim 16.

18. The impurity is an n-type impurity. The film forming method according to claim 1 .

19. The n-type impurity is phosphorus. The film forming method according to claim 18.

20. The impurity-containing gas is diborane gas. The film forming method according to claim 1 .

21. The impurity-containing gas is phosphine. The film forming method according to claim 1 .

22. The metal silicide film is a titanium silicide film or a molybdenum silicide film. The film forming method according to claim 1 .

23. The step (c) is carried out at a higher temperature than the step (b). The film forming method according to claim 1 .

24. (d) before the step (b), removing a native oxide film on a surface of the doped region; The film forming method according to claim 1 .

25. The step (d) includes supplying a gas containing a halogen element and a basic gas as processing gases to the substrate; The film forming method according to claim 24.

26. a processing vessel for accommodating a substrate having a doped region formed on a surface thereof, the doped region including silicon to which an impurity is added; a supply unit that supplies a gas to the substrate accommodated in the processing vessel; A control unit; Equipped with The control unit controls the supply unit, forming a diffusion prevention layer containing the impurity on the doped region; forming a metal film on the doped region on which the diffusion prevention layer is formed, and forming a metal silicide film by reaction between the metal film and silicon in the doped region; Run The step of forming the diffusion prevention layer includes supplying an impurity-containing gas that contains the impurity to the substrate without generating plasma. Processing system.

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