Method for treating a substrate and apparatus for treating a substrate

Abstract

To provide a technique for forming a titanium nitride layer having characteristics suitable as an adhesion layer when embedding a wiring metal in a recess.SOLUTION: When processing a substrate in which a silicon insulator layer having a recess for embedding a wiring metal is laminated and a titanium-containing layer or a tungsten layer is exposed on a bottom surface of the recess, plasma of gas containing nitrogen atoms is supplied to the substrate to nitride a side wall of the silicon insulator layer and the titanium-containing layer or the tungsten layer. Next, a titanium nitride layer is formed on the side wall surface of the insulator layer.SELECTED DRAWING: Figure 4D

Description

[Technical Field]

[0001] The present disclosure relates to a method of processing a substrate and an apparatus for processing a substrate. [Background technology]

[0002] In the manufacturing process of semiconductor devices, a recess such as a via hole or a trench is formed in an insulator layer formed on a semiconductor wafer (hereinafter also referred to as "wafer"), which is a substrate, and a conductor, which is a wiring metal, is embedded in the recess. As the integration of semiconductor devices progresses, the opening width of the recess tends to become smaller and smaller.

[0003] On the other hand, an adhesion layer may be provided to improve adhesion between the sidewall of the recess and the wiring metal. In recesses that are becoming smaller, the formation of the adhesion layer has a significant impact on suppressing void formation and filling the wiring metal with low resistance. In addition, when forming the adhesion layer, it is also important to suppress an increase in contact resistance between the wiring metal filled in the recess and the underlying material.

[0004] Patent Document 1 describes a technique in which tungsten is embedded in a contact hole formed in an interlayer insulating film to form a conductive plug, and then NH3 plasma is applied to the surface of the interlayer insulating film exposed by CMP. NH3 plasma is used to bond NH groups to oxygen atoms on the surface of the interlayer insulating film, thereby suppressing the effect of oxygen atoms on the crystallinity of the Ti film when a Ti film is formed on the top surface of the interlayer insulating film by physical vapor deposition (PVD) in a subsequent process. However, Patent Document 1 does not describe a technique for forming an adhesion layer suitable for embedding a conductive plug in a contact hole. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-94311 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure provides a technique for forming a titanium nitride layer having suitable properties as an adhesive layer when embedding a wiring metal in a recess. [Means for solving the problem]

[0007] The present disclosure provides a method for processing a substrate, comprising: a step of supplying plasma of a gas containing nitrogen atoms to the substrate, when a silicon insulator layer having a recess formed therein for burying a wiring metal therein and a titanium-containing layer or a tungsten layer exposed at the bottom of the recess, to the substrate, and nitriding a sidewall of the silicon insulator layer and the titanium-containing layer or the tungsten layer; Then, a titanium nitride layer is formed on the sidewall surface of the insulating layer. [Effects of the Invention]

[0008] According to the present disclosure, when embedding wiring metal in recesses, a titanium nitride layer having properties suitable as an adhesive layer can be formed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a plan view showing an example of the configuration of a substrate processing apparatus according to an embodiment; [Figure 2] 2 is a vertical cross-sectional side view showing an example of the configuration of a plasma processing module provided in the substrate processing apparatus. FIG. [Figure 3] 2 is a vertical cross-sectional side view showing an example of the configuration of a TiN film forming module provided in the substrate processing apparatus. FIG. [Figure 4A] FIG. 2 is a first enlarged vertical cross-sectional side view relating to wafer processing. [Figure 4B] FIG. 10 is a second enlarged vertical cross-sectional side view relating to wafer processing. [Figure 4C]FIG. 10 is a third enlarged vertical cross-sectional side view relating to wafer processing. [Figure 4D] FIG. 4 is a fourth enlarged vertical cross-sectional side view relating to wafer processing. [Figure 4E] FIG. 5 is an enlarged vertical cross-sectional view of a fifth embodiment of the present invention relating to wafer processing. [Figure 5] FIG. 10 is a plan view showing another example of the configuration of the substrate processing apparatus. [Figure 6] 1 is a graph showing the relationship between film thickness and coverage of the wafer surface in a TiN film formation experiment. [Figure 7] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Substrate processing apparatus 1> An embodiment of an apparatus for processing a substrate according to the present disclosure (hereinafter referred to as "substrate processing apparatus 1") will be described below with reference to Figures 1 to 3. The substrate processing apparatus 1 forms a titanium nitride (TiN) layer 205, which serves as an adhesion layer, on the sidewall of a recess 21 formed on the surface of a wafer W, as shown in the enlarged view of Figure 4E, and then performs a process of embedding ruthenium (Ru), which is an interconnect metal. The substrate processing apparatus 1 includes an atmospheric transfer chamber 11, a load lock chamber 12, a first substrate transfer chamber 13, a second substrate transfer chamber 14, and a plurality of process modules 151 to 153.

[0011] The first substrate transfer chamber 13 and the second substrate transfer chamber 14 are each configured to have a rectangular shape in a plan view, and are connected via, for example, two transfer sections 17. A vacuum atmosphere is set inside the first and second substrate transfer chambers 13, 14 and the transfer section 17. Furthermore, first and second transfer mechanisms 131, 141 are arranged inside the first and second substrate transfer chambers 13, 14, respectively.

[0012] The transfer unit 17 is configured to transfer the wafer W between the first transfer mechanism 131 provided in the first substrate transfer chamber 13 and the second transfer mechanism 141 provided in the second substrate transfer chamber 14. The first substrate transfer chamber 13, the second substrate transfer chamber 14, and the transfer unit 17 correspond to the vacuum transfer chamber in this embodiment. The first transfer mechanism 131 and the second transfer mechanism 141 correspond to the substrate transfer mechanism in this embodiment. The substrate transfer chamber 13 and the substrate transfer chamber 14 are equipped with a vacuum exhaust mechanism. The vacuum exhaust mechanism uses, for example, a turbo molecular pump to create a high vacuum (for example, 1.33×10) inside the substrate transfer chamber 13 and the substrate transfer chamber 14. ―5 Pa(1×10 ―7 By keeping the pressure lower than (less than) Torr, oxidation of the base before the Ru film is formed may be suppressed.

[0013] The direction in which these substrate transfer chambers 13, 14 are lined up is referred to as the front-to-rear direction, with the first substrate transfer chamber 13 on the front side and the second substrate transfer chamber 14 on the rear side. In this case, an atmospheric transfer chamber 11 set to an atmospheric pressure atmosphere is connected to the front side of the first substrate transfer chamber 13 via, for example, three load lock chambers 12. Transfer ports for wafers W and gate valves for opening and closing the transfer ports are respectively located between the first and second substrate transfer chambers 13, 14 and the transfer unit 17, between the load lock chamber 12 and the first substrate transfer chamber 13, and between the load lock chamber 12 and the atmospheric transfer chamber 11, but are not shown in the figures.

[0014] For example, four load ports 101 are connected to the atmospheric transfer chamber 11, and a carrier C accommodating a plurality of wafers W is placed on each load port 101. The atmospheric transfer chamber 11 is provided with an atmospheric transfer mechanism 111, which can transfer wafers W between the carrier C connected to the atmospheric transfer chamber 11 and the load lock chamber 12.

[0015] As viewed from the front side, two plasma processing modules 151 and two TiN film formation modules 152 are connected to each of the two left and right walls of the first substrate transfer chamber 13. A first transfer mechanism 131 provided in the first substrate transfer chamber 13 is configured to transfer wafers W between these four processing modules 151, 152, the interface 17, and the load lock chamber 12. In FIG. 1, symbol GV1 indicates a gate valve.

[0016] The plasma processing module 151 performs pre-processing for forming a TiN layer 205 having suitable properties. The plasma processing module 151 corresponds to the first processing module in this embodiment. The TiN film forming module 152 forms the TiN layer 205 on the sidewall of the recess 21 formed on the surface of the wafer W. The TiN film forming module 152 corresponds to the second processing module in this embodiment.

[0017] Further, as viewed from the front side, two Ru film formation modules 153 are connected to each of the two left and right walls of the second substrate transfer chamber 14, for a total of four Ru film formation modules 153. The second transfer mechanism 141 is configured to transfer wafers W between these four Ru film formation modules 153 and the transfer unit 17. In FIG. 1, the symbol GV2 indicates each gate valve. Each Ru film formation module 153 forms a Ru film to fill Ru in the recess 21. The Ru film formation module 153 corresponds to the third process module in this embodiment.

[0018] <Processing modules 151 to 153> 2 and 3, an example of the configuration of each of the process modules 151 to 153 will be described. These process modules 151 to 153 have a common configuration, which includes a process vessel (first process vessel, second process vessel, third process vessel) 51 that is evacuated to a vacuum atmosphere, a shower head 52 provided at the top of the process vessel 51, and a substrate mounting table (first mounting table, second mounting table, third mounting table) 53 provided within the process vessel 51.

[0019] The shower head 52 is disposed in the processing chamber 51 so as to face the substrate mounting table 53, and its interior forms a gas diffusion space (not shown). The lower part of the shower head 52 is configured as a shower plate, and a plurality of through holes are formed therein so that various gases supplied to the gas diffusion space are uniformly discharged toward the surface of the wafer W mounted on the substrate mounting table 53. The shower head 52 has holes formed in the center of its upper part to which processing gas supply mechanisms 6A and 6B (described later) and a metal source gas supply mechanism (not shown) are connected.

[0020] Three substrate support pins (not shown) are provided on the substrate mounting table 53 in the processing chamber 51 so as to be movable up and down. The substrate support pins are inserted into through holes formed in the substrate mounting table 53 and protrude and retract relative to the upper surface of the substrate mounting table 53, thereby enabling the transfer of the wafer W between the first and second transfer mechanisms 131 and 141 shown in FIG. 1 and the substrate mounting table 53.

[0021] An exhaust pipe 54 having an exhaust hole at its upstream end is connected to the bottom of the processing vessel 51, and a pressure control valve, such as an APC valve (not shown), is installed in the exhaust pipe 54. An exhaust mechanism 55 is installed at the downstream end of the exhaust pipe 54. The processing modules 151 to 153 each include gas supply mechanisms 6A and 6B for supplying various gases into the processing vessel 51 via the shower head 52, and are configured to perform various processes on a wafer W placed on a substrate mounting table 53.

[0022] Next, the characteristic configurations of the individual process modules 151-153 will be described. As shown in Fig. 2, the plasma process module (first process module) 151 includes a process gas supply mechanism 6A. The process gas supply mechanism 6A includes an H2 gas supply mechanism 61 configured to supply H2 gas, an NH3 gas supply mechanism 62 configured to supply NH3 gas, and an H2 gas supply mechanism 61 configured to supply N2 gas. Gases supplied from the gas supply mechanisms 61-63 are supplied into the process chamber 51 via the shower head 52.

[0023] The H gas supply mechanism 61 includes an H gas supply source 61a, a pipe 61b for supplying H gas to the shower head 52, and a flow rate adjustment mechanism M1 provided in the pipe 61b for adjusting the supply flow rate of H gas. The H gas corresponds to a reducing gas used for performing a process of reducing the TiSiO layer 203a (described later) to remove oxygen. From this perspective, the H gas supply mechanism 61 constitutes a reducing gas supply unit of this embodiment.

[0024] Similar to the configuration of the H2 gas supply mechanism 61, the NH3 gas supply mechanism 62 includes an NH3 gas supply source 62a, a pipe 62b, and a flow rate adjustment mechanism M2. The N2 gas supply mechanism 63 includes an N2 gas supply source 63a, a pipe 63b, and a flow rate adjustment mechanism M3. The NH3 gas supplied from the NH3 gas supply mechanism 62 and the N2 gas supplied from the N2 gas supply mechanism 63 are process gases containing nitrogen atoms. The NH3 gas and N2 gas correspond to process gases used for plasma processing of the wafer W before the wafer W is converted into plasma and the TiN layer 205 forming the adhesion layer is formed. From this perspective, the NH3 gas supply mechanism 62 and the N2 gas supply mechanism 63 constitute a process gas supply unit of this embodiment. Note that the process gas supply mechanism 6A may also include an argon gas supply mechanism (not shown) that supplies argon gas as an auxiliary gas to assist in converting the H2 gas, NH3 gas, and N2 gas into plasma, as will be described in the following examples.

[0025] To generate plasma from each processing gas, a high-frequency power supply 592 is connected to the shower head 52 via a matching box 591. Meanwhile, a substrate stage 53, which is positioned opposite the shower head 52, is grounded. This configuration forms a parallel-plate counter electrode system with the shower head 52 as the upper electrode and the substrate stage 53 as the lower electrode. When processing gas is supplied into the processing chamber 51 and high-frequency power is applied from the high-frequency power supply 592 to the shower head 52, capacitively coupled plasma is formed between the upper and lower electrodes due to capacitive coupling. The processing chamber 51 is grounded, and the processing chamber 51 and the shower head 52, and the processing chamber 51 and the substrate stage 53, are insulated by insulating members 57 and 58. The high-frequency power supply 592, the matching box 591, the shower head 52, and the heater 56 constitute a plasma generation unit of this embodiment.

[0026] The method for generating plasma from each processing gas is not limited to the above. Inductively coupled plasma (ICP) may be used, which generates eddy currents by using a high-frequency fluctuating magnetic field formed around an antenna to generate plasma from the processing gas. Furthermore, plasma may be generated by surface-wave plasma (SWP), discharge-produced plasma (DPP), hollow cathode plasma (HCP), or the like. Remote plasma, in which externally generated plasma is introduced into the processing vessel 51, may also be used.

[0027] In the plasma processing module 151, the interior of the processing vessel 51 is adjusted to a pressure atmosphere of, for example, 300 to 1500 Pa, and the heater 56 heats the wafer W placed on the substrate mounting table 53 to a temperature in the range of, for example, 200 to 500° C. Under these conditions, plasma of various processing gases is supplied to the wafer W, whereby plasma processing is performed.

[0028] Next, a characteristic configuration of the TiN film formation module (second processing module) 152 will be described with reference to Fig. 3. The TiN film formation module 152 of this embodiment is configured as a processing module that forms a TiN film by, for example, thermal ALD (Atomic Layer Deposition). Therefore, unlike the previously described plasma processing module 151, the TiN film formation module 152 does not include a plasma generation section (such as a matching box 591 or a high-frequency power supply 592).

[0029] The TiN film formation module 152 also includes a film formation gas supply mechanism 6B. The film formation gas supply mechanism 6B includes a TiCl4 gas supply mechanism 64 configured to supply TiCl4 gas, a titanium (Ti)-containing source gas, and an NH3 gas supply mechanism 65 configured to supply NH3 gas, a nitriding gas. Similar to the configuration of the H2 gas supply mechanism 61 described above, the TiCl4 gas supply mechanism 64 includes a TiCl4 gas supply source 64a, a pipe 64b, and a flow rate adjustment mechanism M4. The TiCl4 gas supply mechanism 64 corresponds to the titanium source gas supply unit of this embodiment. The NH3 gas supply mechanism 65 includes an NH3 gas supply source 65a, a pipe 65b, and a flow rate adjustment mechanism M5. The NH3 gas supply mechanism 65 corresponds to the nitriding gas supply unit of this embodiment. The film formation gas supply mechanism 6B also includes a purge gas supply mechanism (not shown) that supplies, for example, N2 gas or Ar gas as a purge gas for exhausting the supplied TiCl4 gas and NH3 gas from the processing chamber 51.

[0030] In the TiN film formation module 152, the interior of the processing chamber 51 is adjusted to a pressure atmosphere of, for example, 133 to 1333 Pa, and the heater 56 heats the wafer W placed on the substrate mounting table 53 to a temperature in the range of, for example, 300 to 500°C. In thermal ALD, the film formation gas supply mechanism 6B repeatedly supplies gas in the following order: TiCl4 gas → purge gas → NH3 gas → purge gas, thereby forming the TiN layer 205. In each cycle, the supply of NH3 gas → purge gas may be repeated approximately 2 to 10 times. The gas supply time in each cycle is approximately several hundred milliseconds to several seconds.

[0031] Next, the Ru film formation module (third processing module) 153 of this embodiment is configured as a processing module that forms a Ru film by, for example, thermal CVD (Chemical Vapor Deposition). The Ru film formation module 153 is configured almost the same as the TiN film formation module 152 described above, except for the configuration of the film formation gas supply mechanism 6B, and therefore is not individually illustrated.

[0032] The Ru deposition module 153 has a deposition gas supply mechanism that supplies Ru3(CO) 12 The system is equipped with a metal source gas supply mechanism configured to supply Ru3(CO) gas, and a CO gas supply mechanism configured to supply CO gas, which is a reaction control gas. 12 The system is equipped with gas and CO gas supply sources, piping, and a flow rate adjusting mechanism. The metal source gas supply mechanism corresponds to the metal source gas supply unit of this embodiment.

[0033] In the Ru film formation module 153, the inside of the processing chamber 51 is adjusted to a pressure atmosphere of, for example, 1.3 to 133 Pa, and the heater 56 heats the wafer W placed on the substrate mounting table 53 to a temperature in the range of, for example, 130 to 200° C. In the thermal CVD, Ru3(CO) 12 The Ru film is formed by simultaneously and continuously supplying the gas and CO gas.

[0034] As shown in Fig. 1, the substrate processing apparatus 1 includes a control unit 10. The control unit 10 is configured with a computer including a storage unit, a memory, and a CPU that stores a program. The program contains instructions (steps) for outputting control signals from the control unit 10 to each unit of the substrate processing apparatus 1, controlling the transfer of wafers W to each of the processing modules 151 to 153, and controlling the processing of wafers W. The program is stored in a storage unit of the computer, such as a flexible disk, compact disk, hard disk, MO (magneto-optical disk), or non-volatile memory, and is read from the storage unit and installed in the control unit 10.

[0035] <Wafer W Processing> The operation of the substrate processing apparatus 1 having the above-described configuration will be described with reference to FIGS. 4A to 4E. In the substrate processing apparatus 1, first, a carrier C accommodating a wafer W to be processed is transported and placed on a load port 101. In the wafer W to be processed shown in FIGS. 4A to 4E, Ru is embedded in the recesses 21 as a wiring metal for contact with the gate of a FET (Field Effect Transistor), for example. As shown in FIG. 4A, a silicon insulator layer (SiO layer) 202, which is an interlayer insulating film, is laminated on a Si layer 201, which is the upper surface of the wafer W body.

[0036] The recess 21 is formed to penetrate the SiO layer 202. The opening width of the recess 21 is, for example, 10 nm within a range of 5 to 50 nm. For comparison, the opening width of a conventional recess 21 can be 20 nm. A TiSi layer 203, which serves as a contact layer for electrical conduction between the Si layer 201 and the Ru 206, is exposed at the bottom of the recess 21. The TiSi layer 203 can be formed by forming a Ti layer on the bottom of the recess 21, and then heating the wafer W to thermally diffuse silicon toward the Ti layer. The surface of the TiSi layer 203 is oxidized while the wafer W is being transported in a clean room in an air atmosphere, forming a TiSiO layer 203a containing oxygen.

[0037] In the substrate processing apparatus 1, after the TiSi layer 203 is reduced to remove oxygen, pre-processing for forming the TiN layer 205 as an adhesive layer, formation of the TiN layer 205, and embedding of Ru 206 are performed. To explain this together with the operation of the substrate processing apparatus 1, the wafer W is removed from the carrier C by the atmospheric transfer mechanism 111 and transferred to the load lock chamber 12, which is under atmospheric pressure. Next, once the inside of the load lock chamber 12 is adjusted to a vacuum pressure atmosphere, the transfer mechanism 131 transfers the wafer W from the load lock chamber 12 to the plasma processing module 151 and places it on the substrate mounting table 53. In the plasma processing module 151, in preparation for plasma processing, the pressure inside the processing vessel 51 is adjusted and the wafer W is heated by the heater 56.

[0038] 4A, if Ru 206 is embedded while the TiSiO layer 203a is still formed on the surface of the TiSi layer 203, the contact resistance between the TiSi layer 203 and the Ru 206 increases. Therefore, in the plasma processing module 151, a plasma of H2 gas, which is a reducing gas, is first supplied into the processing chamber 51 to remove oxygen contained in the TiSiO layer 203a (FIG. 4A, oxygen removal step). This process reduces the TiSiO layer 203a, returning it to the TiSi layer 203 before oxidation, as shown in FIG. 4B.

[0039] Next, after stopping the supply of H gas plasma, N gas plasma and NH gas plasma are supplied alternately to the processing chamber 51 of the plasma processing module 151 in this order to pre-treat the wafer W (FIG. 4B). This pre-treating process nitrides the SiO layer 202 forming the sidewall of the recess 21 and the TiSi layer 203 exposed at the bottom of the recess 21 (nitriding process). The N gas plasma serves to nitride the surfaces of the SiO layer 202 and the TiSi layer 203 (FIG. 4C). The NH gas plasma serves to nitride the surfaces of the SiO layer 202 and the TiSi layer 203 and to form NH groups on these surfaces. In FIG. 4C, the nitrided SiO layer 202 is referred to as the SiON layer 204, and the nitrided TiSi layer 203 is referred to as the TiSiN layer 203b.

[0040] The TiSiN layer 203b acts to suppress reoxidation of the TiSi layer 203. Furthermore, the SiON layer 204 formed by nitriding the surface of the SiO layer 202 has high adhesion to the TiN layer 205. Furthermore, the NH groups formed by supplying NH gas plasma have high affinity with TiCl contained in the titanium source gas supplied when forming the TiN layer 205. This improves the probability of TiCl adsorption to the SiON layer 204. This provides an effective pretreatment for continuously forming the TiN layer 205 on the surface of the SiO layer 202 (SiON layer 204). From the viewpoint of protecting (preventing desorption of) the NH groups once formed, it is preferable to first perform the treatment with N gas plasma and then the treatment with NH gas plasma.

[0041] After each plasma treatment is completed, the wafer W is transported by the transport mechanism 131 to the TiN film formation module 152 and placed on the substrate mounting table 53. In the TiN film formation module 152, the pressure inside the processing chamber 51 is adjusted and the wafer W is heated by the heater 56 in preparation for the film formation process of the TiN layer 205. Then, the gas supply cycle described above, in which TiCl4 gas and NH3 gas are alternately supplied from the film formation gas supply mechanism 6B into the processing chamber 51, is repeated several to several tens of times to form the TiN layer 205 (step of forming a titanium nitride layer, FIG. 4D). Note that in this step, the TiN layer 205 is also formed on the bottom surface of the recess 21, but is integrated with the TiSiN layer 203b.

[0042] Furthermore, within the recess 21, the surface of the SiO layer 202 is nitrided by the action of the plasma of N2 gas and NH3 gas performed previously, forming a SiON layer 204. Furthermore, NH groups are formed on the surface of the SiON layer 204 by the action of the plasma of NH3 gas. The presence of the SiON layer 204 and the NH groups prevents the film from being interrupted over the entire surface of the sidewall of the recess 21, allowing the formation of a continuous TiN layer 205 with a high coverage.

[0043] As will be shown in the experimental results in the examples described later, the effect of being able to form a continuous TiN layer 205 can be obtained even if the thickness of the TiN layer 205 is thin. As a result, even if the TiN layer 205 is formed in the recess 21 having a smaller opening width than conventional ones, such as 10 nm within the range of 5 to 50 nm as described above, it is possible to prevent the space for embedding Ru from becoming narrow. The thickness of the TiN layer 205 can be, for example, 1.5 nm within the range of 0.5 to 3 nm (3 nm in total for both sidewalls).

[0044] After the formation of the TiN layer 205 is completed, the wafer W is transferred to the Ru film formation module 153 via the transfer mechanism 131, the delivery unit 17, and the transfer mechanism 141, and placed on the substrate mounting table 53. In the Ru film formation module 153, the pressure inside the processing chamber 51 is adjusted and the wafer W is heated by the heater 56 in preparation for the Ru film formation process. Then, Ru3(CO) 12 It supplies gas (including CO gas as a carrier gas) and CO gas for reaction control.

[0045] As a result, Ru3(CO) supplied into the processing vessel 51 12 Thermal CVD proceeds, in which Ru 206 is thermally decomposed on the wafer W. By carrying out thermal CVD for a preset period of time, a Ru layer is formed on the surface of the wafer W, and Ru 206 can be embedded in the recesses 21 (FIG. 4E, a step of embedding a wiring metal).

[0046] After the embedding of Ru 206 is completed, the wafer W is transferred to the load lock chamber 12 via the transfer mechanism 141, the delivery unit 17, and the transfer mechanism 131. Next, the atmosphere in the load lock chamber 12 is switched to an atmospheric pressure atmosphere, and then the processed wafer W is returned to the carrier C by the atmospheric transfer mechanism 111.

[0047] According to the substrate processing apparatus 1 of this embodiment, the recesses 21 are formed in the SiO layer 202, and the wafer W having the TiSi layer 203 exposed on the bottom surface of the recesses 21 is subjected to plasma treatment using N gas or NH gas containing nitrogen atoms. As a result, when Ru 206 is embedded in the recesses 21, a continuous TiN layer 205 can be formed, which has properties suitable for an adhesion layer, and is unlikely to be interrupted even when the film is thin.

[0048] <Variations> 1, an example is shown in which the plasma processing module 151 that performs plasma processing using plasmas of H gas, N gas, and NH gas, and the TiN film formation module 152 that forms the TiN layer 205, are configured separately. However, it is not essential that the processing modules 151 and 152 are configured as separate entities.

[0049] For example, the plasma processing / TiN film formation module 154 provided in the substrate processing apparatus 1a shown in FIG. 5 is configured to be capable of both plasma processing using various process gases and film formation of a TiN layer 205. That is, in the plasma processing / TiN film formation module 154, both the process gas supply mechanism 6A shown in FIG. 2 and the film formation gas supply mechanism 6B shown in FIG. 3 are connected to the processing vessel 51 (the overlapping NH gas supply mechanism 62 and NH gas supply mechanism 65 may be shared). Furthermore, by providing plasma generation units such as the matching box 591 and high-frequency power supply 592 described with reference to FIG. 2, both processes can be performed. The plasma processing / TiN film formation module 154 can be configured such that the substrate mounting table 53 and the processing vessel 51 are shared between a first processing module that performs plasma processing using various gases and a second processing module that forms a TiN layer 205.

[0050] On the other hand, as shown in FIGS. 1 and 5, it is not essential that all of the processing modules 151-155 be provided in a common substrate processing apparatus 1, 1a. Some or all of these processing modules 151-155 may be provided in separate substrate processing apparatuses. As described above, the TiSiN layer 203b formed by performing plasma processing using N2 gas and NH3 gas in the plasma processing module 151 is resistant to oxidation. Therefore, even if the plasma processing module 151, the TiN film deposition module 152, and the Ru film deposition module 153 are provided in different substrate processing apparatuses and atmospheric transport of the wafer W is required between the substrate processing apparatuses, the TiN layer 205 can be formed and Ru 206 can be embedded while suppressing an increase in contact resistance.

[0051] Furthermore, it is not essential to perform both the N2 gas plasma treatment and the NH3 gas plasma treatment. As long as a continuous TiN layer 205 can be formed, either one of the gas plasma treatments may be performed. Furthermore, the H2 gas plasma treatment is not essential. If the oxygen content in the TiSi layer 203 exposed on the bottom surface of the recess 21 is sufficiently low and the effect on contact resistance is small, the oxygen removal treatment using H2 gas plasma may be omitted. Even when both the H2 gas plasma treatment and the N2 gas and NH3 gas plasma treatments are performed, the processing modules for performing these plasma treatments may be configured as separate units.

[0052] In the example described with reference to FIGS. 4A to 4E, Ru is embedded in the recess 21 for contact with the gate of the FET. However, the treatment using plasma of N2 gas and NH3 gas according to the present disclosure can be applied to other configurations. For example, a tungsten layer is exposed on the bottom surface of the recess 21 for contact with the source of the FET. Furthermore, a Ti layer (TiSi layer) laminated on the surface of the SiGe layer or Si layer is exposed on the bottom surface of the recess 21 for contact with the drain of the FET. Even for these configurations, the plasma treatment according to the present disclosure is an effective pretreatment for forming a continuous TiN layer 205, which is less likely to be broken even in a thin film. Furthermore, the wiring metal is not limited to Ru, and may be molybdenum (Mo) or tungsten (W).

[0053] Furthermore, the configuration of the apparatus for forming the TiN layer 205 is not limited to the example shown in Fig. 3. For example, a batch-type film formation apparatus that simultaneously forms films on a plurality of wafers W may be used. In this case, a remote plasma device that supplies plasma of H gas, NH gas, or N gas may be provided in addition to the batch-type film formation apparatus to perform pre-treatment (plasma treatment) for forming the TiN layer 205.

[0054] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Example]

[0055] (experiment) The TiN layer 205 was formed with varying thickness on wafers W that had been subjected to plasma processing with N2 gas and NH3 gas, and on wafers W that had not been subjected to plasma processing, and the coverage was measured.

[0056] A. Experimental Conditions (Example 1) A flat silicon wafer was used as the wafer W, and a mixed gas of 4000 sccm of NH3 gas, 2000 sccm of argon gas, and 4500 sccm of H2 gas was supplied under the conditions of a heating temperature of 450°C and a pressure of 400 Pa for the wafer W. A high frequency power of 450 kHz and 300 W was applied to form a plasma, and the gas was supplied for 60 seconds. The H2 gas in the mixed gas, together with the Ar gas, played the role of an auxiliary gas that assists in forming the plasma of the NH3 gas. Thereafter, the TiCl4 gas → purge gas →<NH3ガス→パージガス> " gas supply cycle, in each cycle<NH3ガス→パージガス> The TiN layer 205 was formed by repeating this process 10 times (hereinafter also referred to as the "10-pulse supply method"). The thickness of the TiN layer 205 was changed by increasing or decreasing the number of gas supply cycles. For each wafer W on which the TiN layer 205 was formed, the coverage of the TiN layer 205 was determined by the ratio of the area on the wafer W where Ti was detected by ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry). Example 2 A TiN layer 205 was formed under the same conditions as in Example 1, except that 4000 sccm of N2 gas was supplied as the mixed gas instead of NH3 gas, and the coverage of the TiN layer 205 was determined.

[0057] Comparative Example 1: A TiN layer 205 was formed on a wafer W that had not been subjected to plasma processing, and the coverage of the TiN layer 205 was determined. Here, the gas supply cycle of TiCl4 gas and NH3 gas was not a 10-pulse supply method, but a normal gas supply cycle in which "TiCl4 gas → purge gas → NH3 gas → purge gas" was repeated was carried out. Comparative Example 2 A TiN layer 205 was formed in the same manner as in Example 1, except that the wafer W was not subjected to plasma processing, and the coverage of the TiN layer 205 was determined.

[0058] B. Experimental Results The experimental results for Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Figure 7. The horizontal axis of Figure 7 represents the film thickness of the TiN layer 205, and the vertical axis represents the coverage of the TiN layer 205. Example 1 is shown as a filled triangle plot, and Example 2 is shown as a white circle plot. Comparative Example 1 is shown as a filled square plot, and Comparative Example 2 is shown as a cross plot. In Figure 6, the plots are concentrated in the area where the coverage is 0.8 or more, so an enlarged view of that area is shown in Figure 7.

[0059] 6 and 7, in Example 1, in which plasma treatment was performed using NH gas, a coverage of 0.98 or more was obtained when the thickness of the TiN layer 205 was 0.8 nm or more. In Example 2, in which plasma treatment was performed using N gas, a coverage of 0.98 or more was obtained when the thickness of the TiN layer 205 was 1.1 nm or more.

[0060] In comparison with these experimental results, in Comparative Example 2, which did not undergo plasma treatment with NH3 gas or N2 gas, a film thickness of 1.9 nm was required to achieve a coverage of 0.98 or more. In Comparative Example 1, even with a film thickness of 2 nm, the coverage remained at around 0.96. Looking at the results of the above examples and comparative examples, it was confirmed that pretreatment using NH3 gas or N2 gas plasma has the effect of preventing the TiN layer 205 from being broken even when it is a thin film, and realizing continuous film formation, for each treatment gas. [Explanation of symbols]

[0061] W wafer 202 SiO layer 203 TiSi layer 203b TiSiN layer 204 SiON layer 205 TiN layer

Claims

1. 1. A method of processing a substrate, comprising: a step of supplying plasma of a gas containing nitrogen atoms to the substrate, when a silicon insulator layer having a recess formed therein for burying a wiring metal therein and a titanium-containing layer or a tungsten layer exposed at the bottom of the recess, to the substrate, and nitriding a sidewall of the silicon insulator layer and the titanium-containing layer or the tungsten layer; and then forming a titanium nitride layer on the sidewall surface of the insulator layer.

2. 2. The method of claim 1, further comprising the step of filling the recess with the interconnect metal in the recess in which the titanium nitride layer is formed.

3. The method of claim 2 wherein the interconnect metal is ruthenium.

4. The method of claim 1, wherein the titanium nitride layer is in the range of 0.5 to 3 nm.

5. The method according to claim 1, wherein the recess has an opening width in the range of 5 to 50 nm.

6. The method according to claim 1 , wherein the gas containing nitrogen atoms is at least one of nitrogen gas and ammonia gas.

7. 2. The method of claim 1, wherein the titanium-containing layer or the tungsten layer contains oxygen, and further comprising the step of supplying a plasma of a reducing gas to the substrate to remove oxygen contained in the titanium-containing layer or the tungsten layer before performing the nitriding step.

8. The method of claim 7 , wherein the reducing gas is hydrogen gas.

9. The method of claim 7 , wherein the titanium-containing layer further comprises silicon.

10. An apparatus for processing a substrate, comprising: a first processing module including: a first processing vessel including a first mounting table on which the substrate is placed; a processing gas supply unit for supplying a processing gas containing nitrogen atoms to the first processing vessel; and a plasma generating unit for generating plasma from the processing gas; a second processing module including: a second processing vessel including a second mounting table on which the substrate is placed; a titanium source gas supply unit for supplying a source gas containing titanium to the second processing vessel; and a nitriding gas supply unit for supplying a nitriding gas to the second processing vessel, the nitriding gas reacting with the titanium source gas to form a titanium nitride layer; a control unit, A silicon insulator layer having a recess formed therein for burying a wiring metal is laminated on the substrate, and a titanium-containing layer or a tungsten layer is exposed on the bottom surface of the recess. the control unit is configured to output a control signal to perform the steps of: placing the substrate on the first mounting table, supplying plasma of the processing gas into the first processing chamber, and nitriding a sidewall of the silicon insulator layer and the titanium-containing layer or the tungsten layer; and then placing the substrate on the second mounting table, supplying the titanium source gas and the nitriding gas into the second processing chamber, and forming a titanium nitride layer on a sidewall surface of the insulator layer.

11. The apparatus according to claim 10 , wherein the first processing module and the second processing module share the mounting table and the processing container.

12. a third processing module including a third processing vessel having a third mounting table on which the substrate is placed, and a metal source gas supply unit for supplying a metal source gas containing an element of the wiring metal to the third processing vessel; 11. The apparatus according to claim 10, wherein the control unit is configured to output a control signal for performing a step of placing the substrate on which the titanium nitride layer has been formed on the third mounting table, and supplying the metal source gas to the third processing chamber to embed the interconnect metal into the recess on which the titanium nitride layer has been formed.

13. 13. The apparatus of claim 12, wherein the interconnect metal is ruthenium and the metal source gas comprises ruthenium.

14. The apparatus of claim 10 , wherein the process gas is at least one of nitrogen gas or ammonia gas.

15. the titanium-containing layer or the tungsten layer contains oxygen; the first processing module includes a reducing gas supply unit for supplying a reducing gas to the first processing vessel, and the plasma generating unit is configured to generate plasma from the reducing gas; 11. The apparatus according to claim 10, wherein the control unit is configured to output a control signal to perform a step of supplying plasma of the reducing gas to the substrate and removing oxygen contained in the titanium-containing layer or the tungsten layer before performing the nitriding step.

16. 16. The apparatus of claim 15, wherein the reducing gas is hydrogen gas.

17. a vacuum transfer chamber to which the first processing container, the second processing container, and the third processing container are connected, and a substrate transfer mechanism disposed in the vacuum transfer chamber; 13. The apparatus according to claim 12, wherein the control unit is configured to output a control signal to perform a step of transporting the substrate by the substrate transport mechanism via the vacuum transport chamber from the mounting table of a processing module in which a preceding process is performed to the mounting table of a processing module in which a next process is performed, between the steps of nitriding, forming the titanium nitride layer, and embedding the wiring metal.

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