Method for treating substrate, and apparatus for treating substrate

Abstract

Provided is a technique for forming a titanium nitride layer having suitable characteristics for an adhesion layer when embedding wiring metal in a recess. In this invention, when treating a substrate in which a silicon insulator layer is stacked, the silicon insulator layer having a recess for embedding wiring metal and the recess having a bottom surface on which a titanium-containing layer or a tungsten layer is exposed, plasma of gas containing nitrogen atoms is supplied to the substrate, whereby a sidewall of the silicon insulator layer and the titanium-containing layer or the tungsten layer are nitrided. Next, a titanium nitride layer is formed on the side wall surface of the insulator layer.

Description

METHOD FOR PROCESSING A SUBSTRATE AND APPARATUS FOR PROCESSING A SUBSTRATE - Patent application

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

[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 a "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] In Patent Document 1, after tungsten is embedded in a contact hole formed in an interlayer insulating film to form a conductor plug, NH ３ The plasma irradiation technique is described. ３ By using plasma to bond NH groups to oxygen atoms on the surface of the interlayer insulating film, the effect of oxygen atoms on the crystallinity of the Ti film is suppressed when a Ti film is formed on the top surface of the interlayer insulating film by a PVD (Physical Vapor Deposition) method in a subsequent process. However, Patent Document 1 does not describe any technology for forming an adhesion layer suitable for embedding a conductor plug in a contact hole.

[0005] JP 2009-94311 A

[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.

[0007] The present disclosure provides a method for processing a substrate, wherein a silicon insulator layer having a recess formed therein for burying a wiring metal is stacked on the substrate, and a titanium-containing layer or a tungsten layer is exposed on the bottom surface of the recess, the method comprising the steps of: supplying plasma of a gas containing nitrogen atoms to the substrate to nitride a sidewall of the silicon insulator layer and the titanium-containing layer or the tungsten layer; and subsequently forming a titanium nitride layer on the sidewall surface of the insulator layer.

[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.

[0009] FIG. 1 is a plan view showing a configuration example of a substrate processing apparatus according to an embodiment. FIG. 2 is a longitudinal sectional side view showing a configuration example of a plasma processing module provided in the substrate processing apparatus. FIG. 3 is a longitudinal sectional side view showing a configuration example of a TiN film formation module provided in the substrate processing apparatus. FIG. 4 is a first enlarged longitudinal sectional side view related to wafer processing. FIG. 5 is a third enlarged longitudinal sectional side view related to wafer processing. FIG. 6 is a fourth enlarged longitudinal sectional side view related to wafer processing. FIG. 7 is a fifth enlarged longitudinal sectional side view related to wafer processing. FIG. 8 is a plan view showing another configuration example of a substrate processing apparatus. FIG. 9 is a graph showing the relationship between film thickness and wafer surface coverage in a TiN film formation experiment. FIG. 10 is an enlarged view of the graph.

[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 forming 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 x 10 ―７ By keeping the pressure lower than 1000 psi (less than 1000 psi) (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. 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, 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 transfer unit 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] Furthermore, 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. 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 the recess 21 with Ru. The Ru film formation module 153 corresponds to the third process module in this embodiment.

[0018] 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. A hole portion is formed in the center of the upper part of the shower head 52, 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 to be movable up and down on the substrate mounting table 53 in the processing vessel 51. 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.

[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 provided in the exhaust pipe 54. An exhaust mechanism 55 is provided 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, a description will be given of the characteristic configuration of each of the processing modules 151 to 153. As shown in FIG. 2, the plasma processing module (first processing module) 151 includes a processing gas supply mechanism 6A. The processing gas supply mechanism 6A supplies H ２ configured to supply H gas ２ Gas supply mechanism 61 and NH ３ configured to supply NH gas ３ A gas supply mechanism 62 and N ２ configured to supply N gas ２ The gas supply mechanism 61 to 63 supplies gases into the processing chamber 51 through the shower head 52.

[0023] H ２ The gas supply mechanism 61 is ２ The gas supply source 61 a and the shower head 52 are connected to H ２ A pipe 61b for supplying gas and a H ２ and a flow rate adjusting mechanism M1 that adjusts the gas supply flow rate. ２ The gas corresponds to a reducing gas that is converted into plasma and used to perform a process of reducing the TiSiO layer 203a to remove oxygen, which will be described later. ２ The gas supply mechanism 61 constitutes a reducing gas supply unit of this embodiment.

[0024] H ２ Similar to the configuration of the gas supply mechanism 61, NH ３ The gas supply mechanism 62 supplies NH ３ The gas supply source 62a, the pipe 62b, and the flow rate adjusting mechanism M2 are provided. ２ The gas supply mechanism 63 supplies N ２ It is equipped with a gas supply source 63a, a pipe 63b, and a flow rate adjusting mechanism M3. ３ NH supplied from the gas supply mechanism 62 ３ , N ２ N supplied from the gas supply mechanism 63 ２ are process gases containing nitrogen atoms. ３ Gas, N ２ The gas corresponds to a processing gas for performing plasma processing on the wafer W before the TiN layer 205 forming the adhesive layer is formed by plasma generation. ３ Gas supply mechanism 62, N ２ The gas supply mechanism 63 constitutes a processing gas supply unit of this embodiment. As shown in the examples described later, the processing gas supply mechanism 6A supplies H ２ Gas, NH ３ Gas, N ２ An argon gas supply mechanism (not shown) may be provided to supply argon gas as an auxiliary gas to assist in converting the gas into plasma.

[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 mounting table 53, which is positioned opposite the shower head 52, is grounded. This configuration forms a parallel plate-type counter electrode, with the shower head 52 serving as the upper electrode and the substrate mounting table 53 serving as the lower electrode. When processing gas is supplied into the processing vessel 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 vessel 51 is grounded, and the processing vessel 51 and the shower head 52, and the processing vessel 51 and the substrate mounting table 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 substrate mounting table 53 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 within a range of, for example, 200 to 500° C. Under these conditions, plasma of various processing gases is supplied to perform plasma processing on the wafer W.

[0028] 3, a description will be given of the characteristic configuration of the TiN film formation module (second processing module) 152. The TiN film formation module 152 of this embodiment is configured as a processing module that forms a TiN film by, for example, thermal atomic layer deposition (ALD). 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 forming module 152 also includes a film forming gas supply mechanism 6B. The film forming gas supply mechanism 6B supplies TiCl 4 , which is a source gas containing titanium (Ti). ４ configured to supply a TiCl gas ４ A gas supply mechanism 64 and a nitriding gas, NH ３ configured to supply NH gas ３ The gas supply mechanism 65 is also provided. ２ Similar to the configuration of the gas supply mechanism 61, TiCl ４ The gas supply mechanism 64 is a gas supply mechanism for supplying TiCl ４ The gas supply source 64a, the pipe 64b, and the flow rate adjusting mechanism M4 are provided. ４ The gas supply mechanism 64 corresponds to the titanium source gas supply unit in this embodiment. ３ The gas supply mechanism 65 supplies NH ３ It is equipped with a gas supply source 65a, a pipe 65b, and a flow rate adjusting mechanism M5. ３ The gas supply mechanism 65 corresponds to the nitriding gas supply unit of this embodiment. ４ Gas and NH ３ As a purge gas for discharging gas from the processing vessel 51, for example, N ２ The chamber is provided with a purge gas supply mechanism (not shown) that supplies gas and Ar gas.

[0030] In the TiN film forming module 152, the inside of the processing vessel 51 is adjusted to a pressure atmosphere of, for example, 133 to 1333 Pa, and the wafer W placed on the substrate mounting table 53 is heated by the heater 56 to a temperature in the range of, for example, 300 to 500° C. In the thermal ALD, the film forming gas supply mechanism 6B supplies “TiCl ４Gas → Purge gas → NH ３ The TiN layer 205 is formed by repeatedly supplying the gas "NH 4 " and "purge gas". ３ The supply of "gas → purge gas" may be repeated about 2 to 10 times. The gas supply time in each cycle is about several hundred milliseconds to several seconds.

[0031] Next, the Ru film formation module (third process module) 153 of this embodiment is configured as a process 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 shown separately.

[0032] The Ru deposition module 153 includes a deposition gas supply mechanism that supplies Ru as a metal source gas containing Ru. ３ (CO) １２ The system includes a metal source gas supply mechanism configured to supply Ru (dodecacarbonyltriruthenium) gas, and a CO gas supply mechanism configured to supply CO gas, which is a reaction control gas. ３ (CO) １２ The system includes a supply source for gas and CO gas, piping, and a flow rate adjusting mechanism. The metal source gas supply mechanism corresponds to the metal source gas supply unit in this embodiment.

[0033] In the Ru film forming module 153, the inside of the processing vessel 51 is adjusted to a pressure atmosphere of, for example, 1.3 to 133 Pa, and the wafer W placed on the substrate mounting table 53 is heated by the heater 56 to a temperature in the range of, for example, 130 to 200° C. In the thermal CVD, Ru is supplied from the film forming gas supply mechanism. ３ (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] <Processing of Wafer W> The operation of the substrate processing apparatus 1 having the above-described configuration will be described with reference to Figures 4A to 4E. In the substrate processing apparatus 1, first, a carrier C containing a wafer W to be processed is transferred and placed on the load port 101. In the wafer W to be processed shown in Figures 4A to 4E, Ru is embedded in the recess 21 as a wiring metal for contact with the gate of an FET (Field Effect Transistor), for example. As shown in Figure 4A, a silicon insulator layer (SiO2 layer) 202, which serves as 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. Furthermore, the surface of the TiSi layer 203 is oxidized during transport of the wafer W in a clean room in an atmospheric atmosphere, forming a TiSiO layer 203a containing oxygen.

[0037] In the substrate processing apparatus 1, after a process of reducing the TiSi layer 203 to remove oxygen, preprocessing for forming a TiN layer 205 as an adhesion layer, formation of the TiN layer 205, and embedding of Ru 206 are performed. To explain 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 in the TiSi layer 203 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 reducing gas, H ２ A gas plasma is supplied to perform a process for removing oxygen contained in the TiSiO layer 203a (FIG. 4A: oxygen removal process). This process reduces the TiSiO layer 203a, returning it to the TiSi layer 203 before oxidation, as shown in FIG. 4B.

[0039] Next is H ２ After the supply of gas plasma was stopped, N 2 was introduced into the processing chamber 51 of the plasma processing module 151. ２ Gas plasma, NH ３ The gas plasma is supplied in this order to perform pretreatment (FIG. 4B). This pretreatment nitrides the SiO layer 202 that forms the sidewall surface of the recess 21 and the TiSi layer 203 that is exposed at the bottom of the recess 21 (nitriding step). ２ The gas plasma serves to nitride the surfaces of the SiO layer 202 and the TiSi layer 203 (FIG. 4C). ３The 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 shown as an SiON layer 204, and the nitrided TiSi layer 203 is shown as a TiSiN layer 203b.

[0040] The TiSiN layer 203b has the effect of suppressing reoxidation of the TiSi layer 203. The SiON layer 204 formed by nitriding the surface of the SiO layer 202 has high adhesion to the TiN layer 205. ３ The NH group formed by supplying the gas plasma is TiCl contained in the titanium source gas supplied when forming the TiN layer 205. ４ Therefore, the affinity of TiCl to the SiON layer 204 is high. ４ As a result, this is 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 elimination of) the NH groups once formed, it is necessary to first ２ Treatment with gas plasma followed by NH ３ It is preferred to carry out the treatment with a plasma of the gas.

[0041] After each plasma treatment is completed, the wafer W is transferred by the transfer 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, TiCl 2 is supplied from the film formation gas supply mechanism 6B into the processing chamber 51. ４ Gas, NH ３ The gas supply cycle described above, in which the gas is switched and supplied, is repeated several to several tens of times to form the TiN layer 205 (step of forming a titanium nitride layer, FIG. 4D). In this step, the TiN layer 205 is also formed on the bottom surface of the recess 21, but it becomes integrated with the TiSiN layer 203b.

[0042] In addition, in the recess 21, the N ２ Gas, NH ３The surface of the SiO layer 202 is nitrided by the action of the gas plasma to form a SiON layer 204. ３ The action of the gas plasma forms NH groups on the surface of the SiON layer 204. The presence of the SiON layer 204 and the NH groups prevents the film from being interrupted over the entire sidewall of the recess 21, allowing the TiN layer 205 to be formed continuously 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 recesses, 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 forming 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 forming 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 forming process. Then, Ru film is supplied from the film forming gas supply mechanism into the processing chamber 51. ３ (CO) １２ Gas (including CO gas as a carrier gas) and CO gas for reaction control are supplied.

[0045] As a result, the Ru supplied into the processing vessel 51 ３ (CO) １２ Thermal CVD proceeds, in which Ru 206 is thermally decomposed on the wafer W. Then, 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 recess 21 is formed in the SiO layer 202, and the wafer W having the TiSi layer 203 exposed at the bottom of the recess 21 is treated with N containing nitrogen atoms. ２ Gas and NH ３ As a result, when Ru 206 is embedded in the recess 21, a continuous TiN layer 205 can be formed, which has properties suitable for an adhesive layer, and is difficult to break even when it is thin.

[0048] <Variations> In the substrate processing apparatus 1 described with reference to FIG. ２ Gas, N ２ Gas, NH ３ In this example, a plasma processing module 151 that performs plasma processing using the plasma of each gas and a 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 modules.

[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 able to perform both plasma processing using each processing gas and film formation processing of the TiN layer 205. That is, in the plasma processing / TiN film formation module 154, both the processing 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 (NH ３ Gas supply mechanism 62 and NH ３(The gas supply mechanism 65 may be shared.) By providing a plasma generation unit such as a matching box 591 and a high-frequency power supply 592 described with reference to FIG. 2, it becomes possible to perform both processes. The plasma processing / TiN film formation module 154 can be said to be configured such that the substrate mounting table 53 and the processing vessel 51 are shared by 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, it is not essential that all of the processing modules 151 to 155 are provided in the common substrate processing apparatus 1, 1a as shown in Figures 1 and 5. Some or all of these processing modules 151 to 155 may be provided in separate substrate processing apparatuses. As described above, in the plasma processing module 151, N ２ Gas, NH ３ The TiSiN layer 203b formed by the gas plasma processing is resistant to oxidation. Therefore, even if the plasma processing module 151, the TiN film formation module 152, and the Ru film formation module 153 are provided in different substrate processing apparatuses and the wafer W needs to be transferred in the atmosphere between the substrate processing apparatuses, the TiN layer 205 can be formed and the Ru 206 can be embedded while suppressing an increase in contact resistance.

[0051] Also, N ２ Treatment with gas plasma and NH ３ It is not essential to perform both the treatment with the plasma of the H gas and the treatment with the plasma of the H gas. If it is possible to form a continuous TiN layer 205, the treatment with the plasma of either one of the gases may be performed. ２ If the oxygen content in the TiSi layer 203 exposed at the bottom of the recess 21 is sufficiently low and the effect on the contact resistance is small, the treatment using H ２ The process of removing oxygen using gas plasma may be omitted. ２ Treatment with gas plasma and N ２ Gas, NH ３Even when both a gas plasma treatment and a gas plasma treatment are performed, the treatment modules for performing these plasma treatments may be configured as separate entities.

[0052] In the example described with reference to FIGS. 4A to 4E, the recess 21 for contact with the gate of the FET is filled with Ru. ２ Gas, NH ３ The process using gas plasma can also 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) stacked 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 process of the present disclosure is an effective pretreatment for forming a continuous TiN layer 205, even if the film is thin and is not easily broken. Furthermore, the wiring metal is not limited to Ru, but 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-forming apparatus that simultaneously forms films on a plurality of wafers W may be used. In this case, the batch-type film-forming apparatus may be provided with a H ２ Gas plasma and NH ３ Gas, N ２ A remote plasma device for supplying gas plasma may be provided in parallel 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.

[0055] (Experiment) N ２ Gas, NH ３ The TiN layer 205 was formed with varying thickness on wafers W that had been subjected to gas plasma processing and 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 NH ３ Gas 4000 sccm, Argon gas 2000 sccm, H ２ The mixed gas was supplied at 4500 sccm, and a high frequency power of 450 kHz and 300 W was applied to form a plasma, which was supplied for 60 seconds. ２ The gases were Ar gas and NH ３ It acts as an auxiliary gas to assist in the formation of plasma from the gas. ４ Gas → Purge gas → <NH ３ In each cycle of the gas supply cycle, NH ３ The TiN layer 205 was formed by a method in which the gas → purge gas cycle was repeated 10 times (hereinafter also referred to as the "10-pulse supply method"). The film 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 ratio of the area in which Ti was detected within the surface of the wafer W by ToF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) was taken as the coverage of the TiN layer 205. (Example 2) NH ３ Replace with gas ２ The TiN layer 205 was formed under the same conditions as in Example 1 except that the gas was supplied at 4000 sccm, 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. ４ Gas, NH ３ The gas supply cycle is not a 10-pulse supply method, but a "TiCl ４ Gas → Purge gas → NH ３ A normal gas supply cycle was carried out in which the "gas → purge gas" was repeated. (Comparative Example 2) A TiN layer 205 was formed in the same manner as in Example 1, except that the plasma treatment was not carried out on the wafer W, 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 6. The horizontal axis of Figure 6 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 region where the coverage is 0.8 or more, so an enlarged view of that region is shown in Figure 7.

[0059] According to the results shown in Figs. 6 and 7, NH ３ In Example 1, in which plasma processing using a gas was performed, a coverage of 0.98 or more was obtained when the film thickness of the TiN layer 205 was 0.8 nm or more. ２ In Example 2, in which plasma processing using gas was performed, a coverage of 0.98 or more was obtained when the thickness of the TiN layer 205 was 1.1 nm or more.

[0060] Compared with these experimental results, NH ３ Gas, N ２ In Comparative Example 2, where no plasma treatment with a gas was performed, a film thickness of 1.9 nm was required to obtain a coverage of 0.98 or more. In Comparative Example 1, even when the film thickness was 2 nm, the coverage remained at about 0.96. Looking at the results of the above Examples and Comparative Examples, it can be seen that the NH ３ Gas, N ２ It was confirmed that the pretreatment with gas plasma had the effect of preventing the TiN layer 205 from being broken even when it was a thin film, and realizing continuous film formation, for each processing gas.

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

Claims

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

2. The method according to 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 said 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 opening width of the recess is 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. 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 carrying out 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 having 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 generation unit for converting the processing gas into plasma; a second processing module including a second processing vessel having 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 to react with the titanium source gas to form a titanium nitride layer; and a control unit; 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. The apparatus according to claim 10, further comprising: a third processing module including: a third processing vessel having a third mounting table on which the substrate is to be mounted; and a metal source gas supply unit for supplying a metal source gas containing an element of the interconnect metal to the third processing vessel; wherein the control unit is configured to output a control signal for performing a step of mounting the substrate on which the titanium nitride layer is formed on the third mounting table, and supplying the metal source gas to the third processing vessel to embed the interconnect metal in the recess in which the titanium nitride layer is formed.

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 and ammonia gas.

15. The apparatus of claim 10, wherein 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 forming unit is configured to generate plasma from the reducing gas; and the control unit is configured to output a control signal for supplying plasma of the reducing gas to the substrate and performing a step of removing oxygen contained in the titanium-containing layer or the tungsten layer before performing the nitriding step.

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

17. The apparatus described in claim 12, comprising a vacuum transfer chamber to which the first processing vessel, the second processing vessel, and the third processing vessel are connected, and a substrate transfer mechanism disposed within the vacuum transfer chamber, wherein the control unit is configured to output a control signal for carrying out a step of transferring the substrate by the substrate transfer mechanism, via the vacuum transfer chamber, from the mounting table of the processing module in which the preceding processing is performed to the mounting table of the processing module in which the next processing is performed, between the performance of the nitriding step, the step of forming the titanium nitride layer, and the step of embedding the wiring metal.

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