Method for processing substrates, and apparatus for processing substrates

Abstract

To provide a technique for removing oxide films on a surface of metal silicide layers formed in the recesses of a substrate.SOLUTION: A substrate processing method includes the steps of: removing an oxide film on the surface of metal silicide layer provided by laminating an insulating layer with recesses formed in the silicon-containing layer and laminating the silicon-containing layer within the recesses, by supplying hydrogen fluoride gas and ammonia gas to the oxide film and reacting with the silicon oxide content contained in the oxide film; and supplying metal halide gas to the oxide film to react with the metal oxide content in the oxide film and remove it.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In the manufacturing process of semiconductor devices, there is a procedure in which recesses such as via holes and trenches are formed in the insulating layer on the semiconductor wafer (hereinafter also referred to as "wafer"), which is the substrate, and conductive materials, which are the wiring materials, are embedded in these recesses. At this time, a native oxide film may be formed on the surface of the metal exposed in the recesses due to contact with the atmosphere. If conductive materials are embedded without removing such a native oxide film, it will cause an increase in wiring resistance.

[0003] Patent Document 1 describes a technique for etching a substrate containing a metal oxide layer that may include one or more metals selected from alkali metals, alkaline earth metals, transition metals, lanthanides, actinides, and late transition metals, and Si, by exposing it to a metal halide. Patent Document 2 describes a technique for removing a fluoride layer by exposing an oxide layer containing one or more of hafnium, tungsten, molybdenum, and titanium to a fluorinating agent, and then exposing the fluoride layer to the same halide etchant. However, these patent documents do not contain any descriptions of techniques specifically for removing oxide films on metal silicides. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-507509 [Patent Document 2] Japanese Patent Publication No. 2022-536475 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present disclosure provides a technique for removing an oxide film on the surface of a metal silicide layer formed in a recess of a substrate.

Means for Solving the Problems

[0006] The method for processing the substrate of the present disclosure is as follows. For a silicon-containing layer, an insulator layer with a recess formed thereon is laminated, and hydrogen fluoride gas and ammonia gas are supplied to an oxide film on the surface of a metal silicide layer laminated and provided on the silicon-containing layer within the recess to react with silicon oxide components contained in the oxide film for removal. And a step of supplying a metal halide gas to the oxide film to react with metal oxide components contained in the oxide film for removal.

Advantages of the Invention

[0007] According to the present disclosure, an oxide film on the surface of a metal silicide layer formed in a recess of a substrate can be removed.

Brief Description of the Drawings

[0008] [Figure 1] It is a plan view showing a configuration example of a substrate processing apparatus according to the present disclosure. [Figure 2] It is a longitudinal sectional side view showing a configuration example of a Ti film forming module provided in the substrate processing apparatus. [Figure 3] It is an explanatory view showing an example of the flow of wafer processing according to an embodiment. [Figure 4A] It is a first enlarged longitudinal sectional side view of the surface of a wafer on which processing according to an embodiment is performed. [Figure 4B] It is a second enlarged longitudinal sectional side view of the surface of the wafer. [Figure 4C] It is a third enlarged longitudinal sectional side view of the surface of the wafer. [Figure 4D] It is a fourth enlarged longitudinal sectional side view of the surface of the wafer. [Figure 4E] It is a fifth enlarged longitudinal sectional side view of the surface of the wafer. [Figure 4F] This is a sixth enlarged longitudinal cross-sectional side view of the surface of the wafer. [Figure 5] This is a plan view showing an example of the configuration of a substrate processing apparatus according to the second embodiment. [Figure 6] This is an explanatory diagram showing an example of the wafer processing flow according to the second embodiment. [Figure 7] This is a plan view showing an example of the configuration of a substrate processing apparatus according to the third embodiment. [Figure 8] This is an explanatory diagram showing an example of the wafer processing flow according to the third embodiment. [Modes for carrying out the invention]

[0009] <Substrate Processing Device 1> The following describes the oxide film on the surface of the MoSi layer 64, which is a metal silicide layer (MoSiO X An embodiment of an apparatus (hereinafter referred to as "substrate processing apparatus 1") that has the function of removing layer 65a) and depositing a conductive Ru film 67 will be described.

[0010] Before beginning the explanation of the configuration of the substrate processing apparatus 1, an example of the surface structure of the wafer W to be processed by the substrate processing apparatus 1 will be described. As shown in Figure 4A, the wafer W to be processed has an SiO layer 62 laminated on a silicon-containing SiGe layer 61, and recesses 60 for embedding ruthenium (Ru), which is a conductor, are formed in the SiO layer 62. A molybdenum (Mo) layer is formed at the bottom of the recesses 60 to adjust the Schottky barrier height, and a MoSi layer 64 is formed by the diffusion of silicon (Si) from the SiGe layer 61.

[0011] When the wafer W having the above configuration is transported through the semiconductor manufacturing plant toward the substrate processing apparatus 1, contact with the atmosphere causes an oxide film called MoSiO to form on the surface of the MoSi layer 64. X Layer 65a is formed. Therefore, the substrate processing apparatus 1 of this embodiment uses the MoSiO X The configuration involves removing layer 65a before embedding Ru.

[0012] Figure 1 is a schematic plan view showing an example configuration of a substrate processing apparatus 1. This substrate processing apparatus 1 comprises an atmospheric transport chamber 11, a load lock chamber 12, a first substrate transport chamber 13 and a second substrate transport chamber 14, and a plurality of processing modules 151 to 154.

[0013] The first substrate transport chamber 13 and the second substrate transport chamber 14 are each configured in a rectangular shape in plan view and are connected, for example, via two transfer sections 17. The interiors of these first and second substrate transport chambers 13 and 14, and the transfer sections 17, are set to a vacuum pressure atmosphere, and their pressures are configured to be equal. In addition, the first and second transport mechanisms 131 and 141 are arranged inside the first and second substrate transport chambers 13 and 14, respectively.

[0014] The transfer unit 17 is configured to transfer wafers between itself and the first transport mechanism 131 located in the first substrate transport chamber 13, or between itself and the second transport mechanism 141 located in the second substrate transport chamber 14. The first substrate transport chamber 13, the second substrate transport chamber 14, and the transfer unit 17 correspond to the vacuum transport chambers of this embodiment. The first transport mechanism 131 and the second transport mechanism 141 correspond to the substrate transport mechanisms of this embodiment.

[0015] The direction in which the first and second substrate transport chambers 13 and 14 are aligned is defined as the length direction, with the first substrate transport chamber 13 being the front side and the second substrate transport chamber 14 being the back side. At this time, an atmospheric transport chamber 11, set to atmospheric pressure, is connected to the front side of the first substrate transport chamber 13, for example, via three load lock chambers 12. Between the first and second substrate transport chambers 13 and 14 and the transfer section 17, between the load lock chamber 12 and the first substrate transport chamber 13, and between the load lock chamber 12 and the atmospheric transport chamber 11, there are wafer transport openings and gate valves for opening and closing these transport openings, respectively, but these are not shown in the diagram.

[0016] For example, four load ports 101 are connected to the atmospheric transport chamber 11, and a carrier C containing multiple wafers W is placed on each load port 101. The atmospheric transport chamber 11 is provided with an atmospheric transport mechanism 111, which can transport wafers W between the carrier C connected to the atmospheric transport chamber 11 and the load lock chamber 12.

[0017] Viewed from the front, the left and right walls of the first substrate transport chamber 13 are connected to one chemical oxide removal (COR) module 151, one post-heat treatment (PHT) module 152, and two Ti film deposition modules 153, respectively. The first transport mechanism 131, provided in the first substrate transport chamber 13, is configured to transport the wafer W between these four modules 151-153, the transfer section 17, and the load lock chamber 12. In Figure 1, the symbol GV1 refers to the gate valve.

[0018] The COR treatment performed by the COR module 151 and the PHT treatment performed by the PHT module 152 are based on the previously described MoSiO X This is a pre-cleaning treatment to remove silicon oxide components contained in layer 65a. Here, MoSiO X Layer 65a is composed of a composite oxide containing Si, Mo, and oxygen (O). In this disclosure, the oxidized portion of Si contained in the composite oxide (SiO X ) is called "silicon oxide," and the oxidized part of Mo (MoO X ) is also called "molybdenum oxide." MoSiO is the oxide film of the metal silicide layer. X In layer 65a, the "molybdenum oxide content" corresponds to the "metal oxide content" in the metal silicide layer.

[0019] The COR module 151 is configured to perform an etching process (COR process) of the natural oxide film using hydrogen fluoride (HF) gas and ammonia (NH3) gas. Further, the PHT module 152 is configured to perform a PHT process of sublimating and removing the reaction products generated by the COR process by heating the wafer W. The configuration examples of the COR module 151 and the PHT module 152 will be described later. The COR module 151 corresponds to the first processing module of the present embodiment.

[0020] Next, the Ti film forming module 153 is configured to form a Ti layer 66, which is a contact metal layer provided between the MoSi layer 64 and the Ru wiring 67a. Further, the Ti film forming module 153 of the present embodiment has a function of removing the MoSiO X layer 65a (since SiO X has already been removed, hereinafter also referred to as "MoO X layer 65b") after the silicon oxide component is removed by the COR process and the PHT process. The MoO X layer 65b corresponds to the metal oxide component of the present embodiment. Also, from the viewpoint of removing the MoO X layer 65b, the Ti film forming module 153 corresponds to the second processing module of the present embodiment. A specific configuration example of the Ti film forming module 153 will be described later while referring to FIG. 2.

[0021] Also, when viewed from the front side, a total of four Ru film forming modules 154, two each, are connected to the left and right two wall portions of the second substrate transfer chamber 14. And the second transfer mechanism 141 is configured to transfer the wafer W between these four Ru film forming modules 154 and the transfer portion 17. In FIG. 2, the symbol GV2 indicates a gate valve.

[0022] Each Ru film forming module 154 is configured to form a Ru film 67 by, for example, CVD (Chemical Vapor Deposition) method using a source gas of Ru which is a conductor. The Ru film forming module 154 corresponds to the fourth processing module of the present embodiment.

[0023] <Ti film forming module 153> Next, a specific configuration example of the Ti film forming module 153 will be described while referring to FIG. 2. The Ti film forming module 153 is configured to supply a film forming gas to the wafer W and form a Ti layer 66 by plasma CVD method. Further, the Ti film forming module 153 supplies a metal halide gas to the wafer W from which the silicon oxide component of the MoSiO X layer 65a has been removed, so as to also have a function of removing the remaining MoO X layer 65b.

[0024] FIG. 2 is a longitudinal side view of the Ti film forming module 153 of the present embodiment. The Ti film forming module 153 includes a substantially cylindrical processing container 210 made of metal having corrosion resistance to chlorine and being grounded. In the central portion of the bottom surface of the processing container 210, for example, a cylindrical exhaust chamber 211 protruding downward is formed, and an exhaust passage 212 is connected to the side surface of the exhaust chamber 211. A vacuum exhaust unit 213 including a pressure regulating valve made of, for example, a butterfly valve and a vacuum pump is connected to the exhaust passage 212. The vacuum exhaust unit 213 serves to evacuate the inside of the processing container 210 to a preset vacuum pressure. The processing of the wafer W is performed in the space inside this processing container 210.

[0025] On the side surface of the processing container 210, a carry-in / out port 214 for carrying in and out the wafer W between the processing container 210 and the above-described first substrate transfer chamber 13 is formed. This carry-in / out port 214 is configured to be openable and closable by a gate valve 215 (GV1 in FIG. 1). Further, a heater 216 for adjusting the temperature inside the processing container 210 is embedded in the wall portion constituting the processing container 210.

[0026] Furthermore, a mounting table 22 is provided inside the processing container 210 to hold the wafer W in a nearly horizontal position. The mounting table 22 is supported by a support portion 221 extending from the bottom of the exhaust chamber 211. A heater 220, which is a heating element, is embedded in the mounting table 22, and the wafer W can be heated to a set temperature. In this example, the heating temperature of the wafer W is set to, for example, 450°C, within the range of 350 to 800°C.

[0027] Furthermore, a high-frequency power supply 223 is connected to the mounting table 22 via a matching unit 222 to supply high-frequency power for ion drawing. In addition, the mounting table 22 is provided with lifting pins (not shown) for holding and raising and lowering the wafer W on the mounting table 22. By raising and lowering the lifting pins, the wafer W can be transferred between the mounting table 22 and the first transport mechanism 131 on the first substrate transport chamber 13 side.

[0028] Furthermore, a flat, disc-shaped shower head 23 for supplying substrate processing gas to the wafer W is provided on the ceiling surface of the processing container 210. The shower head 23 is attached to the processing container 210 via an insulating member 217. A diffusion chamber 231 for diffusing gas is formed inside the shower head 23. Numerous discharge holes 232 for discharging gas toward the wafer W are also provided on the bottom surface of the shower head 23. Furthermore, a heater 235 is embedded in the upper surface of the shower head 23.

[0029] A high-frequency power supply 234, which supplies high-frequency power for plasma formation, is connected to the shower head 23 described above via a matching unit 233. That is, the substrate processing apparatus 1 of this embodiment is a parallel plate type plasma processing apparatus composed of a shower head 23 which forms the upper electrode and a mounting table 22 which forms the lower electrode. A wafer W is placed in the space between the shower head 23 and the mounting table 22, and by supplying a film-forming gas and applying high-frequency power, these gases are ionized and plasma is formed. The high-frequency power supply 234 may be configured to supply high-frequency power at any of the following frequencies: 450 kHz, 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, 100 MHz, or 2.45 GHz. For example, the high-frequency power supply 234 supplies high-frequency power in the range of greater than 0 W and less than or equal to 2000 W.

[0030] Furthermore, the downstream end of the gas supply passage 40 is connected to the diffusion chamber 231 of the showerhead 23. Upstream of this gas supply passage 40, the TiCl4 gas supply pipe 41, which is a supply passage for TiCl4 gas that constitutes the film formation gas for the Ti layer 66, the Ar gas supply pipe 42, which is a supply passage for Ar gas added for plasma generation, and the H2 gas supply pipe 43, which is a supply passage for H2 gas, a reaction gas, converge.

[0031] A TiCl4 gas supply source 410 is connected to the upstream end of the TiCl4 gas supply pipe 41, and a flow rate control unit M41 and a valve V41 are installed in that order from upstream. Similarly, an Ar gas supply source 420 is connected to the upstream end of the Ar gas supply pipe 42, and a flow rate control unit M42 and a valve V42 are installed in that order from upstream. Furthermore, an H2 gas supply source 430 is connected to the upstream end of the H2 gas supply pipe 43, and a flow rate control unit M43 and a valve V43 are installed in that order from upstream.

[0032] These mixed gases of TiCl4 gas, H2 gas, and Ar gas (film-forming gas) flow into the diffusion chamber 231 of the showerhead 23 via the gas supply passage 40 and are supplied into the processing container 210 through the discharge hole 232.

[0033] Furthermore, upstream of the gas supply line 40, a WCl5 gas supply pipe 51 joins it. WCl5 gas is MoO X This corresponds to the metal halide gas used to remove layer 65b. A WCl5 gas supply source 510 is connected to the upstream end of the WCl5 gas supply pipe 51, and a flow rate adjustment unit M51 and a valve V51 are interposed therefrom, in order from the upstream side. The supply source 510 and the flow rate adjustment unit M51 for supplying WCl5 gas constitute the metal halide gas supply unit of this embodiment. The WCl5 gas also flows into the diffusion chamber 231 of the shower head 23 via the gas supply passage 40 and is supplied into the processing container 210 through the discharge hole 232.

[0034] <Other processing modules 151, 152, 153> Although not shown in the diagram, the COR module 151, PHT module 152, and Ru film deposition module 154 are equipped with a processing container 210 and a mounting stage 22, similar to the Ti film deposition module 153 described above. In the case of the COR module 151, a mixed gas of HF gas and NH3 gas used for COR processing is supplied to the processing container 210 via the gas supply passage 40. The gas supply sources and flow rate control units that supply the HF gas and NH3 gas, respectively, constitute the mixed gas supply unit of this embodiment.

[0035] In addition, in the PHT module 152, N2 gas, which forms an inert gas atmosphere in which the PHT treatment is carried out, is supplied to the processing container 210 via the gas supply passage 40. In the PHT module 152, the heater 220 on the mounting table 22 heats the wafer W to, for example, 200°C within the range of 60 to 250°C. Furthermore, the COR module 151 and PHT module 152 of this embodiment are not equipped with a high-frequency power supply 234 for plasma formation, etc.

[0036] Furthermore, in the Ru film deposition module 154, the raw material gas for the Ru film 67 is Ru3(CO) 12 The gas and the carrier gas, CO gas, are supplied to the processing container 210 via the gas supply path 40. Ru3(CO) 12The gas supply source and flow rate control unit that supply gas and CO gas correspond to the raw material gas supply unit in this embodiment. The Ru film deposition module 154 in this embodiment is configured to deposit a Ru film 67 by, for example, thermal CVD. Therefore, unlike the Ti film deposition module 153 described with reference to Figure 2, it does not have a matching unit 233 and high-frequency power supply 234 connected to the shower head 23, nor a matching unit 222 and high-frequency power supply 223 connected to the mounting base 22.

[0037] <Control Unit 100> The substrate processing apparatus 1, having the configuration described above, includes a control unit 100 as shown in Figures 1 and 2. The control unit 100 is composed of a computer including a storage unit for storing a program, memory, and a CPU. The program is structured to execute substrate processing using various modules 151 to 154 by outputting control signals from the control unit 100 to each part of the substrate processing apparatus 1, controlling the supply and disconnection of gases and the supply of high-frequency power. The program is stored in the computer's storage unit, such as a flexible disk, compact disk, hard disk, MO (magneto-optical disk), or non-volatile memory, and is read from this storage unit and installed in the control unit 100.

[0038] <Substrate processing> The details of the substrate processing performed using the substrate processing apparatus 1 with the above configuration will be explained with reference to Figures 3 and 4A to 4F. In the substrate processing apparatus 1, first, the atmospheric transport mechanism 111 removes the wafer W contained in the carrier C and transfers it to the load lock chamber 12, which is under atmospheric pressure, and adjusts the load lock chamber 12 to a vacuum pressure atmosphere. Next, the first transport mechanism 131 transports the wafer W in the load lock chamber 12 to the COR module 151 and places it on the mounting table 22 in the processing container 210.

[0039] In the COR module 151, the temperature of the wafer W placed on the mounting stage 22 is adjusted to a temperature below 60°C, for example, 27°C. Then, a mixed gas of HF gas and NH3 gas is supplied to the wafer W in the processing container 210 from the mixed gas supply unit described above (Figure 4A). It has been found that at temperatures below 60°C, the adsorption probability of HF gas and NH3 gas molecules onto the wafer W is high. Therefore, the molecules of each gas are densely adsorbed on the surface of the wafer W, and MoSiO is formed on the bottom side of the recess 60. X These gas molecules also reach and adsorb into layer 65a. As a result, MoSiO X The silicon oxide (SiO) that makes up layer 65a X ) A chemical reaction proceeds between the HF molecules and NH3 molecules, and reaction products are formed, thereby removing (etching) the silicon oxide (process P11 in Figure 3, step to remove silicon oxide).

[0040] The reaction products generated during the COR treatment include ammonium fluorosilicate ((NH4)2SiF6) and water (H2O). These reaction products adhere to the bottom and side walls of the recesses 60 and the upper surface of the SiO layer 62. In addition, ammonium fluoride (NH4F) is also produced during this COR treatment through the reaction of hydrogen fluoride gas with ammonia gas. These ammonium fluoride molecules also act as etchants and react with silicon oxide to form reaction products. Furthermore, during the COR treatment, ammonium fluoride itself may also be deposited on the surface of the wafer W as a solid component.

[0041] The wafer W, from which silicon oxide has been removed by the COR treatment, is transported from the COR module 151 to the PHT module 152 and placed on the mounting table 22 in the processing container 210. In the PHT module 152, the wafer W is heated to sublimate and remove the reaction products and solid ammonium fluoride generated during the COR treatment. Specifically, N2 gas is supplied into the processing container 210 to adjust the temperature of the wafer W placed on the mounting table 22 to 200°C. As a result, the reaction products and solid ammonium fluoride adhering to the heated wafer W sublimate and are discharged to the outside of the processing container 210 along with the N2 gas (processing P11 in Figure 3, step to remove reaction products).

[0042] Next, the first transport mechanism 131 transports the wafer W to the Ti film deposition module 153. As previously described, in the Ti film deposition module 153, MoSiO X MoO is the remaining material after silicon oxide has been removed from layer 65a. X Two processes are performed: removal of layer 65b (metal oxide content) and deposition of the Ti layer 66.

[0043] First, after placing the wafer W on the mounting stage 22 of the Ti film deposition module 153, the vacuum exhaust unit 213 is used to evacuate the inside of the processing container 210 to a preset pressure. The heater 220 is then used to heat the wafer W to the previously described 450°C. Afterward, WCl5 gas is supplied into the processing container 210 from the metal halide gas supply unit (Figure 4B).

[0044] As shown in Figure 4B, when the WCl5 gas reaches the wafer W, the reaction shown in equation (1) below proceeds. 2MoO3(s)+2WCl5(g)→WO2Cl2(g)+2MoO2Cl2(g)+WCl2(s) …(1)

[0045] Solid WCl2 remains on the surface of wafer W. If the presence of chlorine is undesirable, H2 gas is supplied from the H2 gas supply source 430 along with WCl5 gas to allow the reaction shown in equation (2) below to proceed. WCl2(s)+H2(g)→W(s)+2HCl(g) …(2) By reacting with H2 gas, chlorine is removed as HCl gas, leaving only metallic tungsten (W) on the surface of the wafer W.

[0046] By proceeding with the above equation (1), the MoO remaining in the recess 60 after the COR treatment X Layer 65b can be removed (process P12 in Figure 3, step to remove metal oxides). As a result, as shown in Figure 4C, the inside of the recess 60 is the oxide on the surface of the MoSi layer 64 (MoSiO in Figure 4A). X The state after layer 65a) has been removed.

[0047] MoO X After the process of removing layer 65b is completed, the Ti layer 66, which is a metal layer for contact, is formed. Specifically, the supply of WCl5 gas to the processing container 210 of the Ti deposition module 153 is stopped. Then, while continuing to heat the wafer W and adjust the pressure inside the processing container 210, TiCl4 gas, H2 gas, and Ar gas are supplied from the gas supply sources 410, 420, and 430 at preset flow rates. As a result, the deposition gas, which is a mixture of these gases, is introduced into the processing container 210. Furthermore, by applying high-frequency power from the high-frequency power supply 234 to plasmaize the deposition gas, the deposition of Ti on the wafer W proceeds (processing P13 in Figure 3).

[0048] After the Ti film deposition is performed for a predetermined time, the supply of the deposition gas and the application of high-frequency power are stopped. As a result, as shown in Figure 4D, a Ti layer 66 is formed on the bottom surface of the recess 60.

[0049] Next, the wafer W is transported to the Ru deposition module 154 via the first transport mechanism 131, the transfer section 17, and the second transport mechanism 141. An inert gas is supplied to the first substrate transport chamber 13, the transfer section 17, and the second substrate transport chamber 14 to prevent gas diffusion from the deposition module. The pressure is controlled to 100 Pa, for example, within the range of 20 to 200 Pa. In addition, to prevent oxidation of the surface during transport, a vacuum evacuation mechanism (not shown) is used to evacuate these spaces (first substrate transport chamber 13, transfer section 17, and second substrate transport chamber 14), with a maximum vacuum level of 1.33 × 10⁻⁶. -5 The setting is below Pa. In the Ru deposition module 154, a Ru film 67 is deposited so that Ru is embedded on the upper surface side of the Ti layer 66 formed in the recess 60 (P14 in Figure 3, step of embedding the conductor).

[0050] Specifically, the wafer W is loaded into the processing container 210 of the Ru deposition module 154 and placed on the mounting table 22, and the wafer W is heated by the heater 220 to, for example, 150°C within the range of 130 to 200°C. Furthermore, the pressure inside the processing container 210 is adjusted, and Ru3(CO) is deposited into the processing container 210. 12 It supplies gas (including CO gas, which is the carrier gas).

[0051] As a result, Ru3(CO) supplied into the processing container 210 12 Thermal CVD proceeds on the wafer W, causing thermal decomposition. Then, by performing thermal CVD for a predetermined period, as shown in Figure 5C, MoSiO2 is produced. X The Ru film 67 can be embedded in the recess 60 from which layer 65a has been removed.

[0052] After the deposition of the Ru film 67 is completed, the wafer W is transported to the load lock chamber 12 via the second transport mechanism 141, the transfer section 17, and the first transport mechanism 131. Next, the atmosphere inside 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 transport mechanism 111. The unloaded wafer W is polished using an external CMP (Chemical Mechanical Polishing) device. This process removes the top surface layer, and a wafer W with Ru wiring 67a embedded in the recesses 60 is obtained, as shown in Figure 4F.

[0053] According to the above embodiment, the oxide film (MoSiO) on the surface of the metal silicide layer (MoSi layer 64) formed in the recess 60 of the substrate X The layer 65a) can be removed. As a result, the increase in wiring resistance after the Ru film 67 (Ru wiring 67a) is embedded in the recess 60 can be suppressed. In particular, in the substrate processing apparatus 1 in which the wafer W is transported between processing modules 151 to 154 via the first and second substrate transport chambers 13 and 14, it becomes possible to perform substrate processing while avoiding exposure to the atmosphere, and the formation of unwanted native oxide films can be suppressed.

[0054] <Second Embodiment> Next, the configuration and operation of the substrate processing apparatus 1a according to the second embodiment will be described with reference to Figures 5 and 6. In the substrate processing apparatus 1a and 1b shown in Figures 5 and 7, components common to the substrate processing apparatus 1 described using Figure 1 are denoted by the same reference numerals as those shown in Figure 1.

[0055] The substrate processing apparatus 1a according to the second embodiment uses WCl5 gas, which is a metal halide, to produce MoO2, which is a metal oxide. X The structure is designed to address the problem that a reaction different from the previously described equation (1) also proceeds when layer 65b is removed. As will be described later, in this reaction, MoO XInstead of layer 65b, an oxide of tungsten (W) contained in the WCl5 gas (hereinafter also referred to as the "first metal" in the second embodiment) is formed. If this W oxide remains in the recess 60, it can cause an increase in wiring resistance after Ru is embedded, so it may be necessary to remove the W oxide.

[0056] Therefore, in response to the need to remove W oxides, the substrate processing apparatus 1a of this embodiment deposits a film of a metal that is more easily oxidized than W, such as titanium (Ti) (hereinafter also referred to as the "second metal" in the second embodiment). As a result, the W oxides are reduced by Ti, and MoO X The configuration involves removing the Ti oxide formed in place of layer 65b using an etching gas.

[0057] From the above perspective, the substrate processing apparatus 1a uses WCl5 gas to produce MoO X The system includes a pre-cleaning module 156 that performs only the removal of layer 65b, a reduction Ti deposition module 155 that deposits Ti to reduce W oxides and removes those oxides, and a Ti deposition module 153a that deposits only the Ti layer 66 for contacts.

[0058] Although individual illustrations are omitted, the pre-cleaning module 156, the reduction Ti film deposition module 155, and the Ti film deposition module 153a are each equipped with a processing container 210 and a mounting stage 22, similar to the Ti film deposition module 153 described using Figure 2. The pre-cleaning module 156 is equipped only with the metal halide gas supply unit (WCl5 gas supply pipe 51, WCl5 gas supply source 510 flow rate adjustment unit M51, valve V51) shown in Figure 2, and does not have a configuration for supplying TiCl4 gas, Ar gas, and H2 gas for forming the Ti layer 66. It also does not have a high-frequency power supply 234 for plasmaizing the gas supplied to the processing container 210, nor a high-frequency power supply 223 for ion drawing. The pre-cleaning module 156 corresponds to the second processing module of the second embodiment.

[0059] The Ti deposition module 155 for reduction is configured in much the same way as the Ti deposition module 153 shown in Figure 2, and is equipped with a deposition gas supply unit for supplying a deposition gas which is a mixed gas of TiCl4 gas, H2 gas, and Ar gas. On the other hand, the Ti deposition module 155 for reduction differs from the Ti deposition module 153 in that it is equipped with an etching gas supply unit for supplying an etching gas to remove Ti oxides, instead of a supply unit for supplying WCl5 gas. In this example, the Ti deposition module 155 for reduction uses chlorine (Cl2) gas as the etching gas. For example, the etching gas supply unit is composed of a Cl2 gas supply source and a flow rate adjustment unit (neither of which are shown).

[0060] The Ti deposition module 153a is configured in substantially the same way as the Ti deposition module 153 shown in Figure 2, and includes a deposition gas supply unit for supplying a deposition gas which is a mixed gas of TiCl4 gas, H2 gas, and Ar gas. On the other hand, the Ti deposition module 153a differs from the Ti deposition module 153 in that it does not have a metal halide gas supply unit for supplying WCl5 gas. The Ti deposition module 153a corresponds to the third processing module in this embodiment.

[0061] In the substrate processing apparatus 1a shown in Figure 5, one COR module 151 and one PHT module 152 are connected to the first substrate transport chamber 13, similar to the substrate processing apparatus 1 of the first embodiment. On the other hand, in the substrate processing apparatus 1a of the second embodiment, instead of two Ti film deposition modules 153, one pre-cleaning module 156 and one reduction Ti film deposition module 155 are connected, which is different from the substrate processing apparatus 1 of the first embodiment. In addition, one Ti film deposition module 153a is connected to the second substrate transport chamber 14, and there are three Ru film deposition modules 154.

[0062] The processing of wafer W using this substrate processing apparatus 1a will be explained with reference to Figure 6. In Figure 6, the differences from the substrate processing according to the first embodiment explained with reference to Figure 3 will be explained in detail.

[0063] The wafer W to be processed is subjected to COR processing and PHT processing using the COR module 151 and PHT module 152 (processing P11 in Figure 6). After that, the wafer W is brought into the pre-cleaning module 156 and WCl5 gas is supplied, and MoO X Layer 65b is removed (process P12A in Figure 6, step to remove metal oxides).

[0064] At this point, as shown in Figure 4B, when the WCl5 gas reaches the wafer W, the reaction shown in equation (3) below proceeds in parallel with the reaction in equation (1) described above. MoO3(s)+WCl5(g)→WO3(s)+2MoCl5(g) …(3)

[0065] Here, in the reaction of equation (1), MoO X The Gibbs free energy for the reaction between layer 65b and WCl5 gas is -241 kJ / mol at an absolute temperature of 673 K. On the other hand, the Gibbs free energy for the reaction in equation (3) is -126 kJ / mol under the same temperature conditions. Therefore, both equations (1) and (3) have negative Gibbs free energy, and the reaction proceeds in both cases.

[0066] (3) The reaction of equation (3) produces MoO X While layer 65b is removed, an oxide of the first metal, W (WO3), is formed on the surface of the wafer W. In the substrate processing apparatus 1a of the second embodiment, the wafer W is then brought into the reduction Ti film deposition module 155, and a film deposition gas is supplied to deposit a second metal, reduction Ti (process P12B in Figure 6). When the reduction Ti is deposited and comes into contact with WO3, the reaction shown in equation (4) below proceeds, and WO3 is reduced to W (process to reduce the oxide of the first metal). WO3(s)+3Ti(s)→ W+3TiO …(4)

[0067] Subsequently, the supply of the film-forming gas is stopped, and the gas supplied to the processing container 210 is switched to Cl2 gas. As a result, the reaction shown in equation (5) below proceeds, and TiO is removed (process P12C in Figure 6, step to remove the oxide of the second metal). TiO(s)+Cl2(g)→TiOCl2(g) …(5)

[0068] As a result of the above process, metallic tungsten (W) remains on the surface of the wafer W. In addition, Ti that did not come into contact with WO3 also remains on the surface of the wafer W without being etched. Of this Ti, the portion formed in the recess 60 becomes integrated with the Ti formed in the subsequent Ti deposition module 153a to form the Ti layer 66. Furthermore, the Ti formed on the surface of the SiO layer 62 is polished off by CMP after the formation of the Ru film 67.

[0069] As previously described, the reaction in equation (1) proceeds in parallel with the reaction in equation (3) in which the oxide of W (WO3) is formed. As a result, if it is undesirable for solid WCl2 to remain on the surface of the wafer W, the reaction in equation (2) may be carried out to remove chlorine, for example, by supplying H2 gas before depositing the Ti film for reduction, as is the case with the substrate processing apparatus 1 according to the first embodiment.

[0070] When the removal of TiO is complete, the wafer W is loaded into the Ti deposition module 153a, and deposition gas is supplied to form the Ti layer 66, which is a metal layer for contacts (processing P13A in Figure 6). Subsequently, the process of depositing the Ru film 67 and the operation of unloading the wafer W after processing are the same as when using the substrate processing apparatus 1 described above, so a further explanation is omitted.

[0071] Here, the secondary metal is not limited to titanium (Ti). For example, Mo or Ta may be used as a secondary metal that is more easily oxidized than tungsten (W), and then the oxides of Mo or Ta may be etched with chlorine gas.

[0072] <Third Embodiment> Next, the configuration and operation of the substrate processing apparatus 1b according to the third embodiment will be described with reference to Figures 5 and 6. The substrate processing apparatus 1b according to the third embodiment does not have a PHT module 152 for PHT processing to remove reaction products generated in the COR process. Therefore, the pre-cleaning module 156 does not have MoO X The system utilizes the heating operation of the wafer W during the removal of layer 65b to simultaneously remove reaction products.

[0073] In the substrate processing apparatus 1b shown in Figure 7, two COR modules 151 and two pre-cleaning modules 156 are connected to the first substrate transport chamber 13. Therefore, it does not have a PHT module 152, and MoO X This differs from the substrate processing apparatus 1 according to the first embodiment in that it uses a pre-cleaning module 156 that performs only the removal of layer 65b. In addition, one Ti film deposition module 153a and three Ru film deposition modules 154 are connected to the second substrate transport chamber 14.

[0074] Note that the substrate processing apparatus 1b in Figure 7 illustrates a configuration corresponding to the progress of the reaction of equation (1) described above in the Ti film deposition module 153. When corresponding to the progress of the reaction of equation (3) in the Ti film deposition module 153, for example, one COR module 151, one pre-cleaning module 156, and one reducing Ti film deposition module 155 may be connected to the first substrate transport chamber 13.

[0075] The processing of wafer W using this substrate processing apparatus 1b will be explained with reference to Figure 8. In Figure 8, the differences from the substrate processing according to the first embodiment explained with reference to Figure 3 will be explained in detail.

[0076] First, the wafer W to be processed is subjected to COR processing using the COR module 151 (P11A in Figure 8). After that, the wafer W is brought into the pre-cleaning module 156 and WCl5 gas is supplied, and MoO X Layer 65b is removed. During this process, the wafer W is heated to a temperature in the range of 400-800°C (for example, 450°C), which causes MoO XIn parallel with the removal of layer 65b, the reaction products generated by the COR treatment are removed by sublimation (process P12D in Figure 8).

[0077] Here, Figure 8 shows the COR treatment in the COR module 151 (silicon oxide (SiO X ) removal) and MoO in pre-cleaning module 156 X An example is shown in which the removal of layer 65b is repeated multiple times. By repeating these processes, the MoSiO on the surface of the MoSi layer 64 is removed. X Layer 65a can be reliably removed. Examples of the number of repetitions of these processes include cases where they are performed within the range of 2 to 10 times.

[0078] In particular, in the substrate processing apparatus 1b according to the third embodiment shown in Figure 7, the installation of the PHT module 152 is omitted, and the removal of reaction products of the COR treatment and MoO X The removal of layer 65b is performed in parallel within the pre-cleaning module 156. Therefore, the processing time per cycle can be shortened compared to repeating the process using three processing modules (COR module 151, PHT module 152, and Ti film deposition module 153).

[0079] Furthermore, in the example of the substrate processing apparatus 1b shown in Figure 7, it is possible to provide two sets of COR module 151 and Ti film deposition module 153, thereby suppressing the excessive increase in total processing time that occurs when performing repeated processing. However, even if the COR treatment and the treatment with WCl5 gas are repeated multiple times, the implementation of PHT treatment using the PHT module 152 is not excluded. The treatment using the COR module 151, PHT module 152, and Ti film deposition module 153 may also be repeated.

[0080] In this way, both processes are repeated a predetermined number of times, and MoSiO XOnce layer 65a is removed, a Ti layer 66 for contacts is formed in the Ti deposition module 153a, and a Ru film 67 is deposited in the Ru deposition module 154. The subsequent operation for unloading the wafer W is the same as when using the substrate processing apparatus 1 described above, so a further explanation is omitted.

[0081] <Variations> In each of the mechanisms described above, the metal oxide content (MoO) on the surface of the MoSi layer 64 X The metal halide gas used to remove layer 65b) is not limited to WCl5 gas. For example, WCl6 gas or MoCl5 gas can be used to remove MoO X Layer 65b may be removed.

[0082] Furthermore, the silicon-containing layer is not limited to the example of the SiGe layer 61 described using Figure 4A, but may also be a single silicon layer without germanium. The metal silicide layer may also be a TiSi layer or a WSi layer, in addition to the example of the MoSi layer 64. Even if an oxide film is formed on the surface of these metal silicides, these oxide films can be removed by a combination of COR treatment and treatment with metal halide gas.

[0083] Furthermore, in the removal of silicon oxides by COR treatment (HF gas and NH3 gas) and the removal of metal oxides by metal halide gas, it is not always necessary to perform the COR treatment first. The metal halide gas treatment may be performed first, followed by the COR treatment.

[0084] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0085] 1, 1a, 1b Substrate processing equipment 151 Oxide Removal (COR) Module 153 Ti Thin Film Deposition Module 22 Mounting platform 23 Shower head

Claims

1. A method for processing a substrate, A silicon-containing layer is laminated with an insulating layer having recesses formed therein, and hydrogen fluoride gas and ammonia gas are supplied to the oxide film on the surface of a metal silicide layer laminated on the silicon-containing layer within the recesses to react with and remove the silicon oxide contained in the oxide film. A method comprising the step of supplying a metal halide gas to the oxide film and reacting it with the metal oxides contained in the oxide film to remove them.

2. The method according to claim 1, wherein the step of removing the silicon oxide includes a step of heating the substrate to remove reaction products generated when the silicon oxide reacts with the hydrogen fluoride gas and the ammonia gas.

3. The method according to claim 1, wherein, after the step of removing the silicon oxide, the step of removing the metal oxide is carried out while the substrate is heated, thereby carrying out the removal of the metal oxide and the removal of reaction products generated by the reaction of the silicon oxide with the hydrogen fluoride gas and the ammonia gas in parallel.

4. The method according to claim 1, wherein the step of removing the silicon oxide and the step of removing the metal oxide are repeatedly performed.

5. The method according to claim 1, wherein the silicon-containing layer is a silicon-germanium layer, the metal silicide layer is a molybdenum silicide layer, and the metal oxide component is molybdenum oxide.

6. The aforementioned metal halide gas is WCl ５ Gas or MoCl ５ The method according to claim 1, wherein the gas is used.

7. When the metal contained in the metal halide is called the first metal, if, in the step of removing the metal oxide, the oxide of the first metal remains on the substrate instead of the metal oxide, the step of reducing the oxide of the first metal by forming a film of a second metal that is more easily oxidized than the first metal on the substrate on which the oxide of the first metal remains, The method according to claim 1, further comprising the step of removing the oxide of the second metal that has been formed in place of the oxide of the first metal in the step of reducing the oxide of the first metal using an etching gas.

8. The method according to claim 7, wherein the first metal is tungsten and the second metal is titanium.

9. The method according to claim 8, wherein the etching gas is chlorine gas.

10. The method according to claim 1, comprising the steps of removing silicon oxide and removing metal oxide, then forming a conductive film on the substrate and embedding the conductive material in the recess.

11. A device for processing substrates, A first processing module comprising a processing container equipped with a mounting platform on which the substrate is placed, and a mixed gas supply unit for supplying a mixed gas of hydrogen fluoride gas and ammonia gas to the processing container, A second processing module comprising a processing container equipped with a mounting platform on which the substrate is placed, and a metal halide gas supply unit for supplying metal halide gas to the processing container, It comprises a control unit and, The control unit is configured to output a control signal for performing the following steps: supplying the mixed gas to an oxide film on the surface of a metal silicide layer laminated on the silicon-containing layer within the recesses of a silicon-containing layer, reacting the mixed gas with the silicon oxide content in the oxide film to remove it; and supplying the metal halogen gas to the oxide film, reacting the mixed gas with the metal oxide content in the oxide film to remove it.

12. The system comprises a vacuum transport chamber to which the processing container of the first processing module and the processing container of the second processing module are connected, and a substrate transport mechanism disposed within the vacuum transport chamber. The apparatus according to claim 11, wherein the control unit is configured to output a control signal between the step of removing the silicon oxide and the step of removing the metal oxide, the substrate transport mechanism, and the step of transporting the substrate between the stand of the first processing module and the stand of the second processing module via the vacuum transport chamber.

13. The second processing module includes a heating unit for heating the substrate, The apparatus according to claim 11, wherein the control unit is configured to output a control signal that performs, in parallel, the removal of the metal oxide and the removal of reaction products generated by the reaction of the silicon oxide with the hydrogen fluoride gas and the ammonia gas, by performing the step of removing the metal oxide while the substrate is heated after the step of removing the silicon oxide.

14. The apparatus according to claim 11, wherein the silicon-containing layer is a silicon-germanium layer, the metal silicide layer is a molybdenum silicide layer, and the metal oxide component is molybdenum oxide.

15. The aforementioned metal halide gas is WCl ５ Gas or MoCl ５ The apparatus according to claim 11, wherein the gas is used.

16. The third processing module comprises a processing container equipped with a mounting platform on which the substrate is placed, a film formation gas supply unit for supplying a film formation gas of a second metal that is more easily oxidized than the first metal (when the metal contained in the metal halide is called the first metal), and an etching gas supply unit for supplying an etching gas for etching the oxide of the second metal. The apparatus according to claim 11, wherein the control unit is configured to output a control signal for performing the following steps: reducing the oxide of the first metal by supplying the film-forming gas to the substrate on which the oxide of the first metal remains to form a film of the second metal when, in the step of removing the metal oxide, the oxide of the first metal remains on the substrate instead of the metal oxide; and then removing the oxide of the second metal formed in place of the oxide of the first metal in the step of reducing the oxide of the first metal using the etching gas.

17. The apparatus according to claim 16, wherein the first metal is tungsten and the second metal is titanium.

18. The apparatus according to claim 17, wherein the etching gas is chlorine gas.

19. The fourth processing module comprises a processing container equipped with a mounting platform on which the substrate is placed, and a raw material gas supply unit for supplying a conductive raw material gas to the processing container, The apparatus according to claim 11, wherein the control unit is configured to output a control signal for performing the steps of removing silicon oxide and removing metal oxide, then placing the substrate on the aforementioned stand of the fourth processing module, supplying the raw material gas into the processing container to form a conductive film on the substrate, and embedding the conductive film in the recesses.

Images