Semiconductor device manufacturing methods, processes, substrate processing methods and substrate processing apparatus

Abstract

The present invention relates to a technique for improving the properties of a film. It comprises: (a) a step of preparing a substrate having: a film containing a first metal element, and a film containing a group 13 element or a group 14 element formed on the film containing the first metal element; (b) a step of supplying a gas containing a second metal element to the aforementioned substrate; (c) a step of supplying a first reaction gas to the aforementioned substrate; and (d) a step of forming a film containing a second metal element on the aforementioned substrate by performing (b) and (c), while removing at least a portion of the film containing the group 13 element or the group 14 element formed on the film containing the first metal element.

Description

Technical Field

[0001] This case relates to a method for manufacturing a semiconductor device, a process, a substrate processing method, and a substrate processing device. Prior Art

[0002] In recent years, as semiconductor devices have become increasingly integrated and performant, the use of various metal films has led to the manufacture of three-dimensional semiconductor devices. In NAND flash memory, for example, a tungsten film (W film) is used as the control gate. Furthermore, a titanium nitride (TiN) film, for example, is sometimes used as a barrier film between the W film and the insulating film (see, for example, Patent Documents 1 and 2). Prior Art Literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-69407 Patent Document 2: Japanese Patent Application Publication No. 2018-49898 Summary of the Invention

[0004] (Problems to be solved by the invention)

[0005] However, when another metal film, such as a W film, is formed on the surface of a metal film such as a TiN film, the surface of the metal film may be etched by the film-forming gas used to form the other metal film. Furthermore, if the surface of the metal film is etched, its film properties may be degraded.

[0006] The purpose of this case is to provide a technology that can improve membrane properties. (Methods used to solve problems)

[0007] According to one aspect of the present invention, a technology having the following steps is provided: (a) preparing a substrate comprising: a film containing a first metal element; and a film containing a Group 13 element or a Group 14 element formed on the film containing the first metal element; (B) the step of supplying a gas containing a second metal element to the substrate; (c) supplying a first reaction gas to the substrate; and (d) A process of forming a film containing the second metal element on the substrate while removing at least a portion of the film containing the Group 13 element or the Group 14 element formed on the film containing the first metal element by performing (b) and (c). [Effects of the Invention]

[0008] If according to this case, the membrane can be specifically improved. Simple diagram description

[0009] FIG. 1 is a longitudinal sectional view for explaining the structure of a processing furnace 202 a of a substrate processing apparatus 10 according to one embodiment of the present invention. FIG2 is a cross-sectional view of the processing furnace 202a taken along line AA shown in FIG1. FIG. 3 is a longitudinal sectional view for explaining the structure of a processing furnace 202 b of a substrate processing apparatus 10 according to one embodiment of the present invention. FIG4 is a cross-sectional view of the processing furnace 202 b taken along line AA shown in FIG3 . FIG. 5 is a block diagram illustrating the structure of a control unit of a substrate processing apparatus 10 according to an embodiment of the present invention. FIG. 6 is a diagram showing a substrate processing sequence in a processing furnace 202 a of a substrate processing apparatus 10 according to an embodiment of the present invention. FIG. 7 is a diagram showing a substrate processing sequence in a processing furnace 202 b of a substrate processing apparatus 10 according to an embodiment of the present invention. [FIG. 8(A)] and [FIG. 8(B)] are diagrams for explaining a film formed on a substrate by processing in the processing furnace 202a, and [FIG. 8(C)] is a diagram for explaining a film formed on a substrate by processing in the processing furnace 202b. FIG. 9 is a diagram showing a modified example of the substrate processing sequence in the processing furnace 202 b of the substrate processing apparatus 10 according to one embodiment of the present invention. [FIG. 10(A)] is a diagram showing the structures of Sample 1 and Sample 2 used in this example, and [FIG. 10(B)] and [FIG. 10(C)] are diagrams showing the XPS analysis results of Sample 1 and Sample 2 shown in FIG. 10(A). [Figure 11(A)] is a diagram showing the structures of Sample 1 and Sample 2 used in this example, and [Figure 11(B)] and [Figure 11(C)] are diagrams showing the XPS analysis results of Sample 1 and Sample 2 shown in Figure 11(A). Implementation Method

[0010] <One embodiment of this case>

[0011] An embodiment of the present invention will be described below with reference to Figures 1 to 7 and Figures 8(A) to 8(C). A substrate processing apparatus 10 is an example of an apparatus configured for use in a semiconductor device manufacturing process. The drawings used in the following description are schematic, and the dimensional relationships and ratios of the elements shown in the drawings do not necessarily correspond to reality. Furthermore, the dimensional relationships and ratios of the elements in multiple drawings do not necessarily correspond to reality.

[0012] (1) Configuration of substrate processing apparatus 1 is a longitudinal sectional view of a processing furnace 202a as a first process unit of a substrate processing apparatus (hereinafter referred to as substrate processing apparatus 10) capable of implementing a method for manufacturing a semiconductor device. FIG. 2 is a sectional view of the processing furnace 202a taken along line AA. In addition, this embodiment describes an example in which, after a first metal film and a cover film are formed on a wafer 200 in a processing furnace 202a serving as a first process unit, a second metal film is formed while at least a portion of the cover film formed on the first metal film is removed in a processing furnace 202b serving as a second process unit described later.

[0013] The processing furnace 202a is equipped with a heater 207 as a heating means (heating mechanism, heating system, heating part). The heater 207 is cylindrical and is vertically installed by being supported by a heater base (not shown) as a holding plate.

[0014] Inside heater 207, outer tube 203, forming the reaction vessel (processing container), is concentrically arranged with heater 207. Outer tube 203 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC), and has a cylindrical shape with a closed top and an open bottom. Below outer tube 203, a manifold (inlet flange) 209 is concentrically arranged with outer tube 203. Manifold 209 is made of a metal such as stainless steel (SUS), and has a cylindrical shape with open top and bottom ends. An O-ring 220a is installed between the upper end of manifold 209 and outer tube 203 as a sealing member. With manifold 209 supported on the heater base, outer tube 203 is mounted vertically.

[0015] Inside outer tube 203 is an inner tube 204, which forms the reaction vessel. Inner tube 204 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC), and is cylindrical in shape, with a closed top and an open bottom. The outer tube 203, inner tube 204, and manifold 209 primarily constitute the processing vessel (reaction vessel). The hollow portion of the processing vessel (inside inner tube 204) forms the processing chamber 201a. While the inner tube 204 is included in the processing vessel (reaction vessel) and processing chamber 201a, a configuration without the inner tube 204 is also possible.

[0016] The processing chamber 201 a is configured to accommodate a plurality of wafers 200 as substrates arranged in a horizontal position in a vertical direction using a wafer boat 217 to be described later.

[0017] Within the processing chamber 201a, nozzles 410, 420, and 430 are positioned to penetrate the sidewalls of the manifold 209 and the inner tube 204. These nozzles 410, 420, and 430 are connected to the gas supply pipes 310, 320, and 330, respectively, which serve as gas supply lines. Thus, the substrate processing apparatus 10 is equipped with three nozzles 410, 420, and 430 and three gas supply pipes 310, 320, and 330, enabling the supply of multiple types of gases into the processing chamber 201a. However, the processing furnace 202a of this embodiment is not limited to the configuration described above.

[0018] Gas supply pipes 310, 320, and 330 are equipped with flow controllers (flow control units)—mass flow controllers (MFCs) 312, 322, and 332, respectively, from the upstream side. Furthermore, gas supply pipes 310, 320, and 330 are equipped with on-off valves 314, 324, and 334, respectively. Downstream of valves 314, 324, and 334 in gas supply pipes 310, 320, and 330, gas supply pipes 510, 520, and 530, respectively, are connected to supply inert gas. MFCs 512, 522, and 532 and valves 514, 524, and 534 are respectively equipped in this order from the upstream side.

[0019] Nozzles 410, 420, and 430 are connected to the front ends of the gas supply pipes 310, 320, and 330, respectively. These nozzles 410, 420, and 430 are L-shaped, with their horizontal portions extending through the sidewalls of the manifold 209 and the inner tube 204. The vertical portions of these nozzles 410, 420, and 430 are located within the channel-shaped (grooved) preparation chamber 205a. Within the preparation chamber 205a, they extend upward (above the direction in which the wafers 200 are arranged) along the inner wall of the inner tube 204. The preparation chamber 205a is formed to protrude outward in the radial direction of the inner tube 204 and extend vertically.

[0020] The nozzles 410, 420, and 430 are arranged to extend from the lower region of the processing chamber 201a to the upper region of the processing chamber 201a. A plurality of gas supply holes 410a, 420a, and 430a are provided at positions facing the wafer 200. Thus, the gas supply holes 410a, 420a, and 430a of the nozzles 410, 420, and 430 supply processing gas to the wafer 200. These gas supply holes 410a, 420a, and 430a are provided in plurality from the bottom to the top of the inner tube 204, each having the same opening area and spaced at the same intervals. However, the gas supply holes 410a, 420a, and 430a are not limited to the above configuration. For example, the opening area may gradually increase from the bottom of the inner tube 204 toward the top. Thereby, the flow rate of the gas supplied from the gas supply holes 410a, 420a, and 430a can be made more uniform.

[0021] The gas supply holes 410a, 420a, and 430a of the nozzles 410, 420, and 430 are located at positions extending from the bottom to the top of the wafer boat 217 (described later). Therefore, the process gas supplied from the gas supply holes 410a, 420a, and 430a of the nozzles 410, 420, and 430 into the processing chamber 201a is supplied from the bottom to the top of the wafer boat 217, that is, to the entire area of ​​the wafers 200 accommodated in the wafer boat 217. The nozzles 410, 420, and 430 can be extended from the bottom to the top of the processing chamber 201a, but are preferably extended to near the top of the wafer boat 217.

[0022] A gas containing a first metal element (hereinafter also referred to as “first metal-containing gas”) is supplied from a gas supply pipe 310 into the processing chamber 201 a as a processing gas via an MFC 312 , a valve 314 , and a nozzle 410 .

[0023] A third reaction gas that reacts with the first metal-containing gas is supplied from gas supply pipe 320 into processing chamber 201a as a process gas via MFC 322, valve 324, and nozzle 420. This embodiment also illustrates an example in which the third reaction gas is used as a reaction gas that reacts with a gas containing a Group 13 element or a Group 14 element, described later.

[0024] A Group 13 element- or Group 14 element-containing gas containing a Group 13 element or a Group 14 element is supplied from the gas supply pipe 330 into the processing chamber 201 a via the MFC 332 , the valve 334 , and the nozzle 430 as a processing gas.

[0025] Nitrogen (N2) gas, for example, is supplied as an inert gas from gas supply pipes 510, 520, and 530 into the processing chamber 201a via MFCs 512, 522, and 532, valves 514, 524, and 534, and nozzles 410, 420, and 430. While the following describes an example using N2 gas as the inert gas, other inert gases, such as argon (Ar), helium (He), neon (Ne), and xenon (Xe), may also be used.

[0026] The process gas supply system primarily comprises gas supply pipes 310, 320, 330, MFCs 312, 322, 332, valves 314, 324, 334, and nozzles 410, 420, 430. However, nozzles 410, 420, 430 alone can be considered the process gas supply system. The process gas supply system can also be simply referred to as the gas supply system. When the first metal-containing gas flows from gas supply pipe 310, the first metal-containing gas supply system primarily comprises gas supply pipe 310, MFC 312, and valve 314. However, nozzle 410 can also be considered as part of the first metal-containing gas supply system. Furthermore, when the third reactant gas flows from gas supply pipe 320, the third reactant gas supply system primarily comprises gas supply pipe 320, MFC 322, and valve 324. However, nozzle 420 can also be considered as part of the third reactant gas supply system. When nitrogen-containing gas is supplied as the third reaction gas from gas supply pipe 320, the third reaction gas supply system may also be referred to as the nitrogen-containing gas supply system. Furthermore, when a gas containing a Group 13 or Group 14 element flows from gas supply pipe 330, the Group 13 or Group 14 element-containing gas supply system is primarily comprised of gas supply pipe 330, MFC 332, and valve 334. However, nozzle 430 may also be incorporated into the Group 13 or Group 14 element-containing gas supply system. Furthermore, the inert gas supply system is primarily comprised of gas supply pipes 510, 520, 530, MFCs 512, 522, 532, and valves 514, 524, and 534.

[0027] The gas supply method of this embodiment delivers gas through nozzles 410, 420, and 430 disposed within a preparatory chamber 205a within a cylindrical, annular, longitudinal space defined by the inner wall of the inner tube 204 and the ends of the plurality of wafers 200. Gas is then ejected into the inner tube 204 from a plurality of gas supply holes 410a, 420a, and 430a located in the nozzles 410, 420, and 430, facing the wafers. More specifically, the gas supply holes 410a of the nozzle 410, the gas supply holes 420a of the nozzle 420, and the gas supply holes 430a of the nozzle 430 direct the processing gas, etc., toward a direction parallel to the surface of the wafer 200, that is, horizontally.

[0028] The exhaust hole (exhaust port) 204a is a through-hole, such as a vertically elongated slit-like through-hole, formed in the sidewall of the inner tube 204, facing the nozzles 410, 420, and 430, i.e., 180 degrees opposite the preparatory chamber 205a. Therefore, the gas supplied from the gas supply holes 410a, 420a, and 430a of the nozzles 410, 420, and 430 into the processing chamber 201a and remaining on the surface of the wafer 200 (residual gas) flows through the exhaust hole 204a into the exhaust path 206 formed by the gap formed between the inner tube 204 and the outer tube 203. The gas flowing into the exhaust path 206 then flows into the exhaust pipe 231 and is exhausted outside the processing furnace 202a.

[0029] Exhaust holes 204a are provided at positions facing the plurality of wafers 200 (ideally, positions facing from the top to the bottom of wafer boat 217). Gas supplied from gas supply holes 410a, 420a, and 430a to the vicinity of wafers 200 in processing chamber 201a flows horizontally, that is, parallel to the surfaces of wafers 200, before flowing through exhaust holes 204a into exhaust path 206. In other words, gas remaining in processing chamber 201a is exhausted parallel to the main surfaces of wafers 200 through exhaust holes 204a. Furthermore, exhaust holes 204a are not limited to being slit-shaped through-holes; they may also be formed by a plurality of holes.

[0030] An exhaust pipe 231 for exhausting the atmosphere within the processing chamber 201a is provided within the manifold 209. Connected to the exhaust pipe 231 from the upstream side are a pressure sensor 245 (a pressure detector (pressure detection unit)) that detects the pressure within the processing chamber 201a, an APC (Auto Pressure Controller) valve 243, and a vacuum pump 246 (a vacuum exhaust device). The APC valve 243 can be opened and closed while the vacuum pump 246 is in operation to enable and disable vacuum exhaust within the processing chamber 201a. Furthermore, the pressure within the processing chamber 201a can be adjusted by adjusting the valve opening while the vacuum pump 246 is in operation. The exhaust system, or exhaust line, is primarily composed of the exhaust port 204a, the exhaust path 206, the exhaust pipe 231, the APC valve 243, and the pressure sensor 245. Alternatively, the vacuum pump 246 may be incorporated into the exhaust system.

[0031] Below the manifold 209 is a sealing cap 219, a furnace cover that airtightly closes the lower end opening of the manifold 209. The sealing cap 219 is configured to abut against the lower end of the manifold 209 from the vertically downward side. The sealing cap 219 is formed of a metal such as SUS and is disc-shaped. An O-ring 220b, a sealing member that abuts against the lower end of the manifold 209, is located on the top of the sealing cap 219. On the side of the sealing cap 219 opposite the processing chamber 201a, a rotation mechanism 267 is provided to rotate the wafer boat 217 housing the wafers 200. The rotation shaft 255 of the rotation mechanism 267 passes through the sealing cap 219 and is connected to the wafer boat 217. The rotation mechanism 267 is configured to rotate the wafer boat 217, thereby rotating the wafers 200. The seal cap 219 is configured to be raised and lowered vertically by a boat elevator 115, a lifting mechanism vertically disposed outside the outer tube 203. The boat elevator 115 is configured to move the wafer boat 217 into and out of the processing chamber 201a by raising and lowering the seal cap 219. The boat elevator 115 is a transport device (transport mechanism) that transports the wafer boat 217 and the wafers 200 accommodated therein into and out of the processing chamber 201a.

[0032] The wafer boat 217, serving as a substrate support, is configured to support multiple wafers 200, for example, 25 to 200, in a horizontal position and aligned with their centers, arranged in multiple stages in the vertical direction. The wafer boat 217 is constructed of a heat-resistant material, such as quartz or SiC. Heat insulation plates 218, also made of a heat-resistant material such as quartz or SiC, are supported horizontally in multiple stages at the bottom of the wafer boat 217 (not shown). This configuration minimizes heat transfer from the heater 207 to the sealing cover 219. However, this embodiment is not limited to the above configuration. For example, instead of providing the heat insulation plates 218 at the bottom of the wafer boat 217, a heat insulation cylinder made of a heat-resistant material such as quartz or SiC may be provided.

[0033] As shown in FIG2 , a temperature sensor 263 serving as a temperature detector is installed within inner tube 204. The amount of current supplied to heater 207 is adjusted based on the temperature information detected by temperature sensor 263, thereby achieving a desired temperature distribution within processing chamber 201a. Like nozzles 410 , 420 , and 430 , temperature sensor 263 is L-shaped and located along the inner wall of inner tube 204 .

[0034] FIG3 is a longitudinal sectional view of a processing furnace 202 b as a second process unit included in the substrate processing apparatus 10 , and FIG4 is a sectional view taken along line AA of the processing furnace 202 b . The processing furnace 202b of this embodiment differs from the previously described processing furnace 202a in its internal structure within the processing chamber 201a. The following description will focus on only the parts of the processing furnace 202b that differ from the previously described processing furnace 202a; description of the same parts will be omitted. The processing furnace 202b includes the processing chamber 201b as a second processing chamber.

[0035] In the processing chamber 201b, nozzles 440 and 450 are provided to penetrate the side wall of the manifold 209 and the inner tube 204. The nozzles 440 and 450 are connected to the gas supply pipes 340 and 350, respectively. However, the processing furnace 202b of this embodiment is not limited to the above-mentioned configuration.

[0036] Gas supply pipes 340 and 350 are provided with MFCs 342 and 352, respectively, in order from the upstream side. Furthermore, valves 344 and 354 are provided in gas supply pipes 340 and 350, respectively. Downstream of valves 344 and 354 in gas supply pipes 340 and 350, gas supply pipes 540 and 550, respectively, are connected to supply inert gas. MFCs 542 and 552 and valves 544 and 554 are provided in gas supply pipes 540 and 550, respectively, in order from the upstream side.

[0037] Nozzles 440 and 450 are connected to the front ends of gas supply pipes 340 and 350, respectively. Nozzles 440 and 450 are L-shaped, with their horizontal portions extending through the sidewalls of manifold 209 and inner tube 204. The vertical portions of nozzles 440 and 450 are located within a channel-shaped (grooved) preparatory chamber 205b. Within preparatory chamber 205b, they extend upward (above the direction in which the wafers 200 are arranged) along the inner wall of inner tube 204. This preparatory chamber 205b is formed to protrude outward in the radial direction of inner tube 204 and extend vertically.

[0038] The nozzles 440 and 450 are provided to extend from the lower region of the processing chamber 201 b to the upper region of the processing chamber 201 b , and are provided with a plurality of gas supply holes 440 a and 450 a at positions facing the wafer 200 .

[0039] The gas supply holes 440a, 450a of the nozzles 440, 450 are provided in a plurality of locations at heights extending from the bottom to the top of the wafer boat 217 (described later). Therefore, the processing gas supplied from the gas supply holes 440a, 450a of the nozzles 440, 450 into the processing chamber 201b is supplied to the entire area of ​​the wafers 200 accommodated, from the bottom to the top of the wafer boat 217.

[0040] A gas containing a second metal element (hereinafter also referred to as “second metal-containing gas”) is supplied from the gas supply pipe 340 into the processing chamber 201 b as a processing gas via the MFC 342 , the valve 344 , and the nozzle 440 .

[0041] The first reaction gas that reacts with the second metal-containing gas is supplied from the gas supply pipe 350 into the processing chamber 201 b as a processing gas via the MFC 352 , the valve 354 , and the nozzle 450 .

[0042] N₂ gas, for example, is supplied as an inert gas from gas supply pipes 540 and 550 into processing chamber 201b via MFCs 542 and 552, valves 544 and 554, and nozzles 440 and 450, respectively. While the following describes an example using N₂ gas as the inert gas, other inert gases, such as argon (Ar), helium (He), neon (Ne), and xenon (Xe), may also be used.

[0043] The process gas supply system (process gas supply unit) is primarily comprised of gas supply pipes 340, 350, MFCs 342, 352, valves 344, 354, and nozzles 440, 450. However, nozzles 440, 450 alone can be considered the process gas supply system. The process gas supply system can be simply referred to as the gas supply system. When the second metal-containing gas flows from gas supply pipe 340, the second metal-containing gas supply system is primarily comprised of gas supply pipe 340, MFC 342, and valve 344. However, nozzle 440 can also be considered as part of the second metal-containing gas supply system. Furthermore, when the first reactant gas flows from gas supply pipe 350, the first reactant gas supply system is primarily comprised of gas supply pipe 350, MFC 352, and valve 354. However, nozzle 450 can also be considered as part of the first reactant gas supply system. Furthermore, the first reactant gas supply system can also be referred to as the reducing gas supply system. When hydrogen-containing gas is supplied from gas supply pipe 350 as the first reaction gas, the first reaction gas supply system may also be referred to as the hydrogen-containing gas supply system. Furthermore, the inert gas supply system is primarily comprised of gas supply pipes 540 and 550, MFCs 542 and 552, and valves 544 and 554. The inert gas supply system may also be referred to as the purge gas supply system, dilution gas supply system, or carrier gas supply system.

[0044] (Configuration of the control unit) As shown in Figure 5, the control unit (control means), or controller 121, is configured as a computer with a CPU (Central Processing Unit) 121a, RAM (Random Access Memory) 121b, a memory device 121c, and an I / O port 121d. RAM 121b, memory device 121c, and I / O port 121d are configured to exchange data with CPU 121a via an internal bus. Controller 121 is connected to an input / output device 122, such as a touch panel.

[0045] The memory device 121c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. The memory device 121c readablely stores a control program for controlling the operation of the substrate processing device, a process recipe that records the procedures or conditions of the semiconductor device manufacturing method described later, etc. The process recipe is a combination of processes (steps) that can be executed on the controller 121 to obtain a predetermined result, as a program function. Hereinafter, these process recipes, control programs, etc. are also collectively referred to as programs. When the term "program" is used in this specification, it may include only the process recipe alone, only the control program alone, or a combination of the process recipe and the control program. The RAM 121b is a memory area (work area) configured to temporarily store programs or data read by the CPU 121a.

[0046] The I / O port 121d is connected to the MFC312, 322, 332, 342, 352, 512, 522, 532, 542, 552, valves 314, 324, 334, 344, 354, 514, 524, 534, 544, 554, pressure sensor 245, APC valve 243, vacuum pump 246, heater 207, temperature sensor 263, rotation mechanism 267, wafer boat elevator 115, gate valves 70a~70d, first substrate transfer machine 112, etc., which are respectively possessed by the above-mentioned processing furnaces 202a and 202b.

[0047] The CPU 121 a is configured to read out a control program from the memory device 121 c and execute it, and to read out a prescription etc. from the memory device 121 c in accordance with input of an operation instruction etc. from the input / output device 122 . CPU121a is configured to control the flow adjustment actions of various gases of MFC312, 322, 332, 342, 352, 512, 522, 532, 542, 552, the opening and closing actions of valves 314, 324, 334, 344, 354, 514, 524, 534, 544, 554, the opening and closing actions of APC valve 243 and the pressure adjustment action of APC valve 243 according to pressure sensor 245, the temperature adjustment action of heater 207 according to temperature sensor 263, the start and stop of vacuum pump 246, the rotation and rotation speed adjustment action of wafer boat 217 of rotating mechanism 267, the lifting and lowering action of wafer boat 217 of wafer boat elevator 115, the storage action of wafer 200 into wafer boat 217, etc. according to the contents of the read prescription.

[0048] The controller 121 can be configured by installing the aforementioned program stored in an external memory device (e.g., a magnetic disk such as a magnetic tape, floppy disk, or hard disk, an optical disk such as a CD or DVD, an optical disk such as an MO, or a semiconductor memory such as a USB memory or memory card) 123 into a computer. The memory device 121c or the external memory device 123 is configured as a computer-readable recording medium. Hereinafter, these will be collectively referred to as recording media. In this specification, the term "recording medium" may include only the memory device 121c, only the external memory device 123, or both. Furthermore, the program can be provided to the computer without using the external memory device 123, but rather using communication means such as the internet or a dedicated line.

[0049] (2) Substrate processing step (film forming step) Using Figures 6, 7, and 8(A) to 8(C), an example of a process for manufacturing a semiconductor device is described. In a processing furnace 202a, a first metal film containing a first metal element is formed on a wafer 200, and a cap film is formed on the first metal film. In a processing furnace 202b, a second metal film containing a second metal element is formed on the wafer 200 while removing at least a portion of the cap film formed on the first metal film. In the following description, the operations of the various components of the substrate processing apparatus 10 are controlled by the controller 121.

[0050] The substrate processing step (semiconductor device manufacturing step) of this embodiment has the following steps: (a) preparing a substrate comprising: a film containing a first metal element; and a film containing a Group 13 element or a Group 14 element formed on the film containing the first metal element; (B) the step of supplying a gas containing a second metal element to the substrate; (c) supplying a first reaction gas to the substrate; and (d) A process of forming a film containing the second metal element on the substrate while removing at least a portion of the film containing the Group 13 element or the Group 14 element formed on the film containing the first metal element by performing (b) and (c).

[0051] In this specification, the term "wafer" may mean "the wafer itself" or "a laminate (assembly) of a wafer and predetermined layers or films formed on its surface" (that is, when the term "wafer" includes the predetermined layers or films formed on the surface). Furthermore, the term "wafer surface" may mean "the surface (exposed surface) of the wafer itself" or "the surface of predetermined layers or films formed on the wafer, that is, the outermost surface of the wafer as a laminate." Furthermore, the term "substrate" used in this specification is synonymous with the term "wafer."

[0052] A. Formation of the first metal film First, a wafer 200 is loaded into a processing furnace 202 a serving as a first process unit, and a first metal film containing a first metal element and a cap film containing a Group 13 element or a Group 14 element are formed on the wafer 200 .

[0053] (Wafer loading) Once the wafers 200 are loaded onto the wafer boat 217 (wafer charging), the wafer boat 217 supporting the wafers 200 is lifted by the boat elevator 115 and loaded into the processing chamber 201a (boat loading), as shown in FIG1 . In this state, the seal cap 219 closes the lower opening of the outer tube 203 via the O-ring 220b.

[0054] (Pressure adjustment and temperature adjustment) The vacuum pump 246 evacuates the processing chamber 201a, i.e., the space containing the wafer 200, to the desired pressure (vacuum level). The pressure within the processing chamber 201a is measured by the pressure sensor 245, and the APC valve 243 is feedback-controlled based on this pressure information (pressure adjustment). Furthermore, the heater 207 heats the processing chamber 201a to the desired temperature. The amount of current flowing to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 (temperature adjustment) to achieve the desired temperature distribution within the processing chamber 201a. Rotation of the wafer 200 by the rotation mechanism 267 is then initiated. Exhausting the processing chamber 201a and heating and rotating the wafer 200 continue until at least the processing of the wafer 200 is completed.

[0055] [Including the first metal film forming step] Next, a step of forming a first metal film on the wafer 200 is performed.

[0056] (Including the first metal gas supply step S10) Valve 314 is opened to allow the first metal-containing gas to flow through gas supply pipe 310. The first metal-containing gas is supplied into processing chamber 201a from gas supply hole 410a of nozzle 410 at a flow rate controlled by MFC 312 and exhausted through exhaust pipe 231. Simultaneously, valve 514 is opened to allow an inert gas, such as N₂, to flow through gas supply pipe 510. The inert gas flowing through gas supply pipe 510 is supplied into processing chamber 201a along with the first metal-containing gas at a flow rate controlled by MFC 512 and exhausted through exhaust pipe 231. Furthermore, to prevent the first metal-containing gas from entering nozzles 420 and 430, valves 524 and 534 are opened to allow the inert gas to flow through gas supply pipes 520 and 530. The inert gas is supplied into processing chamber 201a through gas supply pipes 320 and 330 and nozzles 420 and 430 and exhausted through exhaust pipe 231.

[0057] At this time, APC valve 243 is adjusted to set the pressure within processing chamber 201 to, for example, a range of 1 to 3990 Pa. The supply flow rate of the first metal-containing gas controlled by MFC 312 is set to, for example, a range of 0.1 to 2.0 slm. The supply flow rates of the inert gas controlled by MFCs 512, 522, and 532 are each set to, for example, a range of 0.1 to 20 slm. In the following, the temperature of heater 207 is set so that the temperature of wafer 200 is, for example, within the range of 300 to 650°C. The supply time of the first metal-containing gas to wafer 200 is, for example, within the range of 0.01 to 30 seconds. In this disclosure, the description of a numerical range such as "1 to 3990 Pa" means that the lower and upper limits are inclusive. Therefore, for example, "1 to 3990 Pa" means "1 Pa or more and 3990 Pa or less." The same applies to other numerical ranges.

[0058] At this time, a first metal-containing gas is supplied to the wafer 200. Here, the first metal-containing gas is, for example, a gas containing titanium (Ti) as a first metal element, and as an example, titanium tetrachloride (TiCl 4 ) gas containing a halogen element can be used.

[0059] (Purification Step S11) After a predetermined time has passed since the start of the supply of the first metal-containing gas, valve 314 is closed to stop the supply of the first metal-containing gas. At this time, APC valve 243 of exhaust pipe 231 remains open, and vacuum pump 246 is used to evacuate the interior of processing chamber 201a, removing any remaining unreacted first metal-containing gas or any gas that has contributed to the formation of the first metal-containing film. Valves 514, 524, and 534 remain open to maintain the supply of inert gas into processing chamber 201a. The inert gas acts as a purge gas, effectively removing any remaining unreacted first metal-containing gas or any gas that has contributed to the formation of the first metal-containing film from processing chamber 201a.

[0060] (Third Reaction Gas Supply Step S12) After a predetermined time has passed since the start of the purge, valve 324 is opened to allow the third reactant gas to flow through the gas supply pipe 320. The third reactant gas is supplied into the processing chamber 201a from the gas supply hole 420a of the nozzle 420 at a flow rate controlled by MFC 322 and exhausted through the exhaust pipe 231. Simultaneously, valve 524 is opened to allow an inert gas to flow through the gas supply pipe 520. Furthermore, to prevent the third reactant gas from entering the nozzles 410 and 430, valves 514 and 534 are opened to allow an inert gas to flow through the gas supply pipes 510 and 530.

[0061] At this time, APC valve 243 is adjusted to set the pressure within processing chamber 201a to, for example, a range of 1 to 3990 Pa. The supply flow rate of the third reactant gas controlled by MFC 322 is set to, for example, a range of 0.1 to 30 slm. The supply flow rates of the inert gas controlled by MFCs 512, 522, and 532 are each set to, for example, a range of 0.1 to 20 slm. The supply time of the third reactant gas to wafer 200 is set to, for example, a range of 0.01 to 30 seconds.

[0062] At this time, a third reaction gas is supplied to the wafer 200. Here, the third reaction gas is, for example, an N-containing gas containing nitrogen (N). For example, ammonia (NH 3 ) gas can be used as the N-containing gas.

[0063] (Purification Step S13) After a predetermined time has passed since the start of the supply of the third reaction gas, valve 324 is closed to stop the supply of the third reaction gas. The third reaction gas remaining in the processing chamber 201a, which has not reacted or has contributed to the formation of the first metal film, is then removed from the processing chamber 201a according to the same process as step S11.

[0064] (Scheduled number of times) By sequentially performing the above-described cycle of steps S10 to S13 one or more times (a predetermined number of times (p)), a first metal-containing film containing the first metal element having a predetermined thickness is formed on wafer 200, as shown in FIG8(A). It is desirable to repeat the above-described cycle a plurality of times. Here, a TiN film, for example, is formed on wafer 200 as the first metal-containing film.

[0065] [Cap film forming step] Next, a capping film is formed on the wafer 200 having the first metal film formed on its surface. The capping film is a film containing a Group 13 element or a Group 14 element, and functions as an anti-oxidation film to prevent oxidation of the outermost surface of the first metal film.

[0066] (Supplying Gas Containing Group 13 or Group 14 Element Step S20) Valve 334 is opened to allow a gas containing a Group 13 or Group 14 element to flow through the gas supply pipe 330. The gas containing a Group 13 or Group 14 element is supplied into the processing chamber 201a through the gas supply hole 430a of the nozzle 430 at a controlled flow rate by the MFC 332 and exhausted through the exhaust pipe 231. Simultaneously, valve 534 is opened to allow an inert gas to flow through the gas supply pipe 530. Furthermore, to prevent the gas containing a Group 13 or Group 14 element from entering the nozzles 410 and 420, valves 514 and 524 are opened to allow an inert gas to flow through the gas supply pipes 510 and 520.

[0067] At this time, APC valve 243 is adjusted to set the pressure within processing chamber 201 to, for example, a range of 1 to 3990 Pa. The flow rate of the gas containing a Group 13 or Group 14 element, controlled by MFC 332, is set to, for example, a range of 0.1 to 30 slm. The flow rates of the inert gas controlled by MFCs 512, 522, and 532 are each set to, for example, a range of 0.1 to 20 slm. The duration of supply of the gas containing a Group 13 or Group 14 element to wafer 200 is set to, for example, a range of 0.01 to 30 seconds.

[0068] At this time, a gas containing a Group 13 or Group 14 element is supplied to wafer 200 having the first metal-containing film formed on its surface. The Group 13 or Group 14 element-containing gas is, for example, a silicon-containing gas containing silicon (Si), such as dichlorosilane (SiH₂Cl₂, DCS). Using a Group 13 or Group 14 element-containing gas facilitates sublimation and removal of the cap film during formation of the second metal-containing film, described later.

[0069] Group 14 elements include at least one element such as silicon (Si) and germanium (Ge). Gases containing Group 14 elements include, for example, gases containing these elements and at least one of hydrogen (H), halogen elements (fluorine (F), chlorine (Cl)), and alkyl groups (such as methyl CH 3). Gases containing Si include, for example, silane-based gases and halogenated silane-based gases. Silane-based gases include, for example, monosilane (SiH 4) gas, disilane (Si 2H 6) gas, and trisilane (Si 3H 8) gas. Halogenosilane-based gases include, for example, dichlorosilane (SiH 2Cl 2), trichlorosilane (SiHCl 3), tetrachlorosilane (SiCl 4), and hexachlorosilane (Si 2Cl 6) gas.

[0070] (Purification Step S21) After a predetermined time has passed since the start of supply of the gas containing the Group 13 or Group 14 element, valve 334 is closed to stop the supply of the gas containing the Group 13 or Group 14 element. Then, through the same process as step S11, any remaining unreacted gas containing the Group 13 or Group 14 element in the processing chamber 201a or any gas that has contributed to the formation of the cap film is removed from the processing chamber 201a.

[0071] (Third Reaction Gas Supply Step S22) After a predetermined time has passed since the start of the purge, valve 324 is opened to allow the third reactant gas to flow through gas supply pipe 320. The third reactant gas is supplied into processing chamber 201a from gas supply port 420a of nozzle 420 at a flow rate controlled by MFC 322 and exhausted through exhaust pipe 231. Simultaneously, valve 524 is opened to allow an inert gas to flow through gas supply pipe 520. Furthermore, to prevent the third reactant gas from entering nozzles 410 and 430, valves 514 and 534 are opened to allow an inert gas to flow through gas supply pipes 510 and 530.

[0072] At this time, APC valve 243 is adjusted to set the pressure within processing chamber 201a to, for example, a range of 1 to 3990 Pa. The supply flow rate of the third reactant gas controlled by MFC 322 is set to, for example, a range of 0.1 to 30 slm. The supply flow rates of the inert gas controlled by MFCs 512, 522, and 532 are each set to, for example, a range of 0.1 to 20 slm. The supply time of the third reactant gas to wafer 200 is set to, for example, a range of 0.01 to 30 seconds.

[0073] At this time, the third reaction gas is supplied to the wafer 200. Here, the third reaction gas is, for example, NH 3 gas containing N, such as N-containing gas.

[0074] (Purification Step S23) After a predetermined time has passed since the start of the supply of the third reaction gas, valve 324 is closed to stop the supply of the third reaction gas. The third reaction gas remaining unreacted or contributing to the formation of the cap film in the processing chamber 201a is then removed from the processing chamber 201a by the same process as step S11.

[0075] (Scheduled number of times) By repeating the above-described cycle of steps S20 through S23 one or more times (a predetermined number of times (n)), a cap film of a predetermined thickness is formed on wafer 200 having the first metal film formed on its surface, as shown in FIG8(B). The above-described cycle is preferably performed multiple times, and the supply cycle is ideal. The thickness of the cap film formed here is ideally 0.2 to 3 nm. If the cap film thickness is thicker than 3 nm, even in the second metal film forming step described later, the cap film may not be removed and may remain. Furthermore, if the thickness is thinner than 0.2 nm, the underlying first metal film may be oxidized. In other words, during the second metal film forming step, the oxidized first metal film may be etched, resulting in a degradation of the properties of the first metal film. Here, the degradation of the properties of the first metal film refers to a reduction in barrier performance when the first metal film is a barrier film. Therefore, the cap film is ideally formed to a thickness of 0.2 nm or greater, which can suppress oxidation of the first metal film. Increasing the cap film's thickness enhances the first metal film's oxidation suppression effect, but the cap film may not be removed during the formation of the second metal film. Therefore, in this process, a cap film with a thickness of 0.2 to 3 nm, ideally 0.2 to 2 nm, is formed on wafer 200, on which the first metal film is formed. Setting the thickness to 2 nm or less allows removal of the cap film during the second metal film formation process. For example, a silicon nitride (SiN) film containing Si, a Group 14 element, is formed as the cap film. Here, 0.2 nm represents the thickness of one atomic layer when the cap film is composed of SiN. Since the thickness of one atomic layer varies depending on the type of cap film, the film thickness (number of layers) can also be adjusted depending on the type of cap film. Forming a film with a thickness of one atomic layer achieves the effect of suppressing oxidation of the first metal film. If the thickness is less than one atomic layer, holes will form, and the oxidation suppression effect of the first metal film will be insufficient. Furthermore, by setting the cap film to a thickness of several atomic layers, the oxidation suppression effect can be further achieved. Furthermore, with a layer thickness of one atomic layer, pinholes may form, and oxidation of the first metal film may occur through these pinholes. Therefore, a cap film thickness of two atomic layers or more but less than a few atomic layers is ideal. Forming a cap film of two atomic layers or more can suppress the formation of pinholes. Pinholes can also be caused by steric hindrance due to the molecular size of the raw material gas used in forming the cap film, or by the reaction characteristics of the raw material gas or the reaction gas. Furthermore, by setting the cap film to a thickness of several atomic layers, during the formation step of the second metal film, at least a portion of the cap film formed on the first metal film can be removed while the second metal film is formed. Here, when the cap film is SiN, the thickness of two to several atomic layers is set to 0.4 to 1.8 nm. By setting the thickness to 1.8 nm or less, the cap film can be removed at the initial stage of the second metal film formation process, reducing the number of layers containing the second metal film and the cap film. Layers containing the second metal film and the cap film may degrade the electrical properties of the second metal film.

[0076] (Post-purification and atmospheric pressure recovery) Inert gas is supplied into the processing chamber 201a through gas supply pipes 510, 520, and 530 and exhausted through exhaust pipe 231. The inert gas acts as a purge gas, purging the processing chamber 201a and removing any remaining gas or byproducts (post-purge). The atmosphere in the processing chamber 201a is then replaced with the inert gas (inert gas replacement), and the pressure in the processing chamber 201a is restored to normal pressure (atmospheric pressure recovery).

[0077] (Wafer removal) The sealing cap 219 is then lowered by the boat elevator 115, opening the lower end of the outer tube 203. The processed wafers 200, with the first metal film and the cap film formed on them, are then unloaded from the lower end of the outer tube 203 to the exterior of the outer tube 203 while supported by the boat 217 (wafer unloading). The processed wafers 200 are then removed from the boat 217 (wafer release).

[0078] B. Formation of a second metal film Next, wafer 200 processed in processing furnace 202a is loaded into processing furnace 202b, serving as the second process unit. Specifically, wafer 200 having a first metal film and a cap film formed thereon is prepared in processing furnace 202b. The pressure and temperature within processing chamber 201b are then adjusted to the desired pressure and temperature distribution. This process differs from the aforementioned processing furnace 202a only in the gas supply process. Therefore, the following description will focus on differences from the aforementioned processing furnace 202a process, with the same parts omitted.

[0079] [Including the second metal film forming step] Next, a step of forming a second metal-containing film containing a second metal element is performed on the wafer 200 having the cap film formed on the surface thereof while removing at least a portion of the cap film formed on the first metal-containing film.

[0080] (Including the second metal gas supply step S30) Valve 344 is opened to allow the second metal-containing gas to flow through gas supply pipe 340. The second metal-containing gas is supplied into processing chamber 201b from gas supply hole 440a of nozzle 440 at a flow rate controlled by MFC 342 and exhausted through exhaust pipe 231. Simultaneously, valve 544 is opened to allow an inert gas, such as N₂, to flow through gas supply pipe 540. The inert gas flowing through gas supply pipe 540 is supplied into processing chamber 201b along with the second metal-containing gas at a flow rate controlled by MFC 542 and exhausted through exhaust pipe 231. Furthermore, to prevent the second metal-containing gas from entering nozzle 450, valve 554 is opened to allow the inert gas to flow through gas supply pipe 550. The inert gas is supplied into processing chamber 201b via gas supply pipe 350 and nozzle 450 and exhausted through exhaust pipe 231.

[0081] At this time, APC valve 243 is adjusted to set the pressure within processing chamber 201 to, for example, a range of 0.1 to 6650 Pa. The supply flow rate of the second metal-containing gas, controlled by MFC 342, is set to, for example, a range of 0.01 to 10 slm. The supply flow rates of the inert gas, controlled by MFCs 542 and 552, are each set to, for example, a range of 0.1 to 20 slm. The second metal-containing gas is supplied to wafer 200 for, for example, a range of 0.01 to 30 seconds. The temperature of heater 207 is set so that the temperature of wafer 200 is, for example, within the range of 250 to 550°C. The gas flowing within processing chamber 201b contains only the second metal gas and the inert gas. The supply of the second metal-containing gas removes the cap film on wafer 200 while forming a second metal-containing film (e.g., a film having a thickness ranging from less than one atomic layer to several atomic layers) on wafer 200 (the underlying film on the surface).

[0082] At this time, a second metal-containing gas is supplied to the wafer 200 having the cap film formed on its surface. Here, the second metal-containing gas may be, for example, tungsten hexafluoride (WF6) gas containing tungsten (W) as the second metal element and fluorine (F) as a halogen-containing gas.

[0083] At this time, the cap film is sublimed by the supply of the second metal-containing gas. That is, the cap film reacts with the halogen element contained in the second metal-containing gas, and the cap film is removed (etched). Specifically, for a SiN film, an example of a cap film, by supplying WF6 gas, an example of a second metal-containing gas, the SiN and WF6 react, and W is adsorbed on the surface of wafer 200, producing silicon tetrafluoride (SiF4) and N2. Since SiF4 is easily sublimated, the SiF4 is sublimed, and the N2 is removed by the subsequent purge in step S31. In other words, the cap film is removed.

[0084] Here, the term "removal of the cap film" also includes a state where a portion of the cap film remains. In other words, a portion of the cap film may remain within the second metal film. For example, in a device structure, a TiN film may be formed on an aluminum oxide (AlO) film, and a W film may be formed on top of that. In this case, the W film functions as an electrode, while the TiN film does not. Therefore, even if an insulating film is present between the W and TiN films, the electrical properties of the individual films are minimally affected.

[0085] (Purification Step S31) After a predetermined time has passed since the start of the supply of the second metal-containing gas, valve 344 is closed to stop the supply of the second metal-containing gas. At this time, APC valve 243 of exhaust pipe 231 remains open, and vacuum pump 246 is used to evacuate the interior of processing chamber 201b, removing any remaining unreacted second metal-containing gas from processing chamber 201b, or any gas that contributes to the removal of the cap film and the formation of the second metal-containing film. Valves 544 and 554 remain open to maintain the supply of inert gas into processing chamber 201b. The inert gas acts as a purge gas, effectively removing any remaining unreacted second metal-containing gas from processing chamber 201b, or any gas that contributes to the removal of the cap film and the formation of the second metal-containing film.

[0086] (First Reaction Gas Supply Step S32) After a predetermined time has passed since the start of the purge, valve 354 is opened to allow the first reactant gas to flow through gas supply pipe 350. The first reactant gas is supplied into processing chamber 201b from gas supply hole 450a of nozzle 450 at a flow rate controlled by MFC 352 and then exhausted through exhaust pipe 231. Simultaneously, valve 554 is opened to allow inert gas to flow through gas supply pipe 550. The inert gas flowing through gas supply pipe 550 is supplied into processing chamber 201b along with the first reactant gas at a flow rate controlled by MFC 552 and then exhausted through exhaust pipe 231. Furthermore, to prevent the first reactant gas from entering nozzle 440, valve 544 is opened to allow inert gas to flow through gas supply pipe 540. The inert gas is supplied into processing chamber 201b via gas supply pipe 340 and nozzle 440 and then exhausted through exhaust pipe 231.

[0087] At this time, APC valve 243 is adjusted to set the pressure within processing chamber 201b to, for example, a range of 1 to 3990 Pa. The supply flow rate of the first reaction gas, controlled by MFC 352, is set to, for example, a range of 0.1 to 50 slm. The supply flow rates of the inert gas, controlled by MFCs 542 and 552, are each set to, for example, a range of 0.1 to 20 slm. The first reaction gas is supplied to wafer 200 for, for example, a range of 0.1 to 20 seconds. The temperature of heater 207 is set so that the temperature of wafer 200 reaches, for example, a range of 200 to 600°C. The gases flowing within processing chamber 201b consist solely of the first reaction gas and the inert gas. The supply of the first reaction gas removes the cap film on wafer 200 while forming a second metal-containing film (e.g., less than one atomic layer to several atomic layers thick) on wafer 200 (the underlying film on the surface).

[0088] At this time, the first reaction gas is supplied to the cap film formed on the surface of the wafer 200. The first reaction gas is, for example, a reducing gas, and hydrogen (H2) gas containing hydrogen (H) (hereinafter also referred to as "hydrogen-containing gas") can be used.

[0089] The supply of the first reaction gas removes the halogen elements in the film, further removing the cap film. Specifically, WF₆ gas, an example of a second metal-containing gas, and H₂ gas, an example of a first reaction gas, are supplied to wafer 200, on the surface of which the cap film is formed. The WF₆ and H₂ react to produce hydrogen fluoride (HF), forming a W film with the F removed. Furthermore, the HF generated by this reaction removes the SiN film, which serves as the cap film. In other words, the cap film is removed by the halogen elements contained in the second metal-containing gas, and the cap film is further removed by the HF generated by the supply of the second metal-containing gas and the first reaction gas.

[0090] Specifically, by forming a cap film on the first metal-containing film, oxidation of the first metal-containing film is suppressed, and when the second metal-containing film is formed on the cap film, the cap film can be sublimated and eliminated. This allows the formation of a second metal-containing film with a low content of Group 13 or Group 14 elements in the cap film.

[0091] Here, the supply flow rate of the first reaction gas is lower than the supply flow rate of the second metal-containing gas. After a predetermined period (a predetermined number of times), it is changed to a flow rate that is approximately equal to the supply flow rate of the second metal-containing gas. Here, the term "approximately equal flow rate" means a margin of error of approximately 10%. By initially supplying the first reaction gas at a higher flow rate than the supply flow rate of the second metal-containing gas, the reaction between the halogen element contained in the second metal-containing gas and the cap film is promoted, thereby removing the cap film. Furthermore, after the cap film is removed after the predetermined period, the supply flow rate of the first reaction gas is changed to approximately the same as the supply flow rate of the second metal-containing gas. This promotes the reaction between the first reaction gas and the second metal-containing gas, thereby forming a second metal-containing film low in halogen elements. This allows the second metal-containing film low in halogen elements to be formed on the first metal-containing film while suppressing etching of the first metal-containing film due to the formation of the second metal-containing film.

[0092] Furthermore, the supply flow rate of the first reactant gas can be initially set to a flow rate greater than the supply flow rate of the inert gas serving as the carrier gas, and then, after a predetermined period (a predetermined number of times), changed to a flow rate less than the inert gas supply flow rate. By initially supplying the first reactant gas at a flow rate greater than the carrier gas flow rate, the reaction between the second metal-containing gas and the first reactant gas is promoted, increasing the amount of HF generated and removing the cap film. Furthermore, after the cap film is removed after the predetermined period, the supply flow rate of the first reactant gas is set to a flow rate less than the inert gas supply flow rate, thereby suppressing the formation of reaction byproducts.

[0093] (Purification Step S33) After a predetermined time has passed since the start of the supply of the first reaction gas, valve 354 is closed to stop the supply of the first reaction gas. Then, through the same process as step S11, the first reaction gas remaining in the processing chamber 201b, which has not reacted or has contributed to the removal of the cap film and the formation of the second metal film, is removed from the processing chamber 201.

[0094] (Scheduled number of times) By repeating the above-described cycle of steps S30 through S33 one or more times (a predetermined number of times (m)), a second metal-containing film containing the second metal element of a predetermined thickness can be formed on wafer 200 while the cap film formed on wafer 200 is sublimated. That is, as shown in FIG8(C), at least a portion of the cap film formed on the first metal-containing film can be removed while the second metal-containing film of a predetermined thickness is formed on wafer 200. The above-described cycle is preferably performed multiple times, with the number of cycles (m) of the second metal-containing film formation step being greater than the number of cycles (n) of the cap film formation step. That is, m>n (m and n are positive integers). In this manner, a second metal-containing film of a predetermined thickness can be formed on wafer 200 while the cap film formed on wafer 200 is sublimated.

[0095] (Post-purification and atmospheric pressure recovery) Inert gas is supplied into the processing chamber 201b through gas supply pipes 540 and 550 and exhausted through exhaust pipe 231. The inert gas acts as a purge gas, purging the processing chamber 201b and removing any remaining gas or byproducts (post-purge). The atmosphere in the processing chamber 201b is then replaced with the inert gas (inert gas replacement), and the pressure in the processing chamber 201b is restored to normal pressure (atmospheric pressure recovery).

[0096] (Wafer removal) The sealing cap 219 is then lowered by the wafer boat elevator 115, opening the lower end of the outer tube 203. The processed wafers 200, supported by the wafer boat 217, are then unloaded from the lower end of the outer tube 203 to the exterior of the outer tube 203 (wafer unloading). The processed wafers 200 are then removed from the wafer boat 217 (wafer release).

[0097] (3) Effects of this embodiment According to this embodiment, one or more of the following effects can be achieved. (a) The film properties can be improved. (b) In particular, oxidation of the surface of the barrier film (including the first metal film) can be suppressed. (c) Furthermore, the barrier film can be suppressed from being etched, thereby improving the barrier properties of the barrier film. (d) The resistivity of the metal-containing film (including the second metal film) formed on the barrier film can be reduced. (e) The properties of the metal-containing film formed on the barrier film can be improved.

[0098] <Other embodiments> The above specifically describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be implemented without departing from the spirit and scope of the present invention.

[0099] (Variation) FIG9 shows a modified example of the substrate processing sequence of one embodiment of the present invention. This modified example differs from the aforementioned embodiment in the second metal film forming step. Specifically, in the second metal film forming step, a second metal-containing gas and a first reaction gas are supplied to form a second metal film of a predetermined thickness on wafer 200 while removing at least a portion of the cover film. Then, the second metal-containing gas and a second reaction gas, which is different from the first reaction gas, are supplied to form another film containing the second metal element on the second metal film. The other film containing the second metal element formed on the second metal film contains the second metal element contained in the second metal film and has a lower resistivity than the second metal film. This modified example allows the formation of a second metal film with a low resistivity while removing at least a portion of the cover film.

[0100] Here, when WF₆ gas is used as the second metal-containing gas, H₂ gas, which is a first hydrogen-containing gas, is used as the first reaction gas, and B₂H₆ gas, which is a second hydrogen-containing gas, is used as the second reaction gas. By supplying WF₆ gas and H₂ gas a predetermined number of times (m), at least a portion of the SiN film, an example of a cap film formed on the first metal-containing film, is removed while a W film with low SiN and F residues is formed on wafer 200. Subsequently, by supplying WF₆ gas and B₂H₆ gas a predetermined number of times (q), a low-resistivity W film is formed. In other words, a low-resistivity second metal-containing film can be formed on the first metal-containing film while suppressing etching of the first metal-containing film due to the formation of the second metal-containing film.

[0101] The above embodiment describes an example of using DCS gas as the gas containing a Group 13 or Group 14 element in the cap film formation process. However, this is not limiting and is also applicable when using different gases. For example, hexachlorosilane (Si2Cl6, abbreviated as HCDS) gas can also be used as the gas containing a Group 13 or Group 14 element. When HCDS gas is supplied as the gas containing a Group 13 or Group 14 element and NH3 gas is supplied as the third reactant gas, Si2Cl6 and NH3 react to produce SixNy, chlorine (Cl2), and hydrochloric acid (HCl), thereby forming a SiN film as the cap film on wafer 200 having the first metal film formed on its surface.

[0102] Furthermore, the above embodiment describes an example using H₂ gas as the first reactant gas in the second metal film formation step, but the present invention is not limited to this and is also applicable when using different gases. For example, monosilane (SiH₄) gas or disilane (Si₂H₆) gas, which contain silicon (Si) and hydrogen (H), can also be used as the first reactant gas. Using a gas containing Si and H, such as SiH₄ gas, as the first reactant gas accelerates the reaction and increases the amount of HF generated, compared to the case of using H₂ gas described above. This accelerates the etching (removal) of the SiN film by HF.

[0103] Furthermore, the above embodiment is also applicable when using diborane (B₂H₆) gas or monoborane (BH₃) gas, which contains boron (B) and hydrogen (H), as the first reaction gas in the second metal film formation step. Using a gas containing B and H, such as B₂H₆ gas, as the first reaction gas accelerates the reaction and increases the amount of HF generated compared to using H₂ gas, thereby accelerating the etching (removal) of the SiN film by HF. Furthermore, the resistivity of the second metal film, such as a W film, formed on the first metal film, such as a TiN film, can be reduced.

[0104] Here, SiH₄ or B₂H₆ reacts more readily with WF₆ than H₂. Therefore, using SiH₄ or B₂H₆ as the first reactant gas accelerates the reaction with WF₆, increasing the amount of HF generated and accelerating the removal of the SiN film by HF. Furthermore, the reaction between WF₆ and SiH₄ (or B₂H₆) forms a W film before the SiN film is removed, sometimes leaving a SiN film underneath the W film. Furthermore, when using H₂ as the first reactant gas, the reaction with WF₆ is slower than when using SiH₄ or B₂H₆, resulting in less residual SiN film.

[0105] Furthermore, the above embodiment describes a configuration in which, after the first metal film forming step and the cap film forming step are performed in the same processing furnace 202a (in-situ), the second metal film forming step is performed in the processing furnace 202b (ex-situ). This configuration suppresses oxidation of the surface of the first metal film and forms the second metal film on the first metal film. However, the present invention is not limited to this configuration. The second metal film forming step may be performed continuously in the same processing furnace as the first metal film forming step and the cap film forming step. In other words, the wafer 200 with the cap film formed on its surface may not be removed from the processing chamber 201a and may be continuously performed while stored in the processing chamber 201a. In other words, the processing may be performed continuously within the same processing chamber (in-situ).

[0106] Furthermore, the above embodiment describes an example of using a TiN film as the first metal-containing film, but is not limited thereto and can also be applied when using a metal-containing film such as a molybdenum (Mo)-containing film, a ruthenium (Ru)-containing film, or a copper (Cu)-containing film.

[0107] Furthermore, while the above embodiments describe the use of a SiN film as a cap film containing a Group 13 or Group 14 element, this is not limiting. The present invention is also applicable to films containing Group 13 elements such as boron (B), aluminum (Al), gallium (Ga), and indium (In), or films containing Group 14 elements such as Si and germanium (Ge). For example, in addition to SiN films, nitride films such as aluminum nitride (AlN) films can be used as cap films. These films can inhibit oxidation of the underlying metal-containing film and, when a metal-containing film different from the underlying metal-containing film is formed on the cap film, prevent sublimation. Furthermore, SiN films are more easily sublimated and extinguished than AlN films.

[0108] Gases containing Group 13 elements include, for example, gases containing these elements and at least one of hydrogen (H), halogen elements (fluorine (F), chlorine (Cl)), and alkyl groups (e.g., methyl CH₃). Gases containing Al include, for example, trimethylaluminum (Al(CH₃)₃) gas and aluminum trichloride (AlCl₃) gas. Using such gases enables the formation of AlN films.

[0109] Furthermore, the above embodiment illustrates an example of performing purification between each step including the second metal film forming process, but is not limited to this. Purification may not be performed between each step including the second metal film forming process, and the second metal-containing gas and the first reaction gas, or the second metal-containing gas and the second reaction gas, may be supplied simultaneously.

[0110] The following describes embodiments, but the present invention is not limited to these embodiments. Example 1

[0111] First, as shown in FIG10(A), using the processing furnace 202a of the substrate processing apparatus 10, the following are prepared: a sample 1 in which a TiN film and a SiN film as a cap film are formed on a wafer 200 by performing the substrate processing sequence of FIG6 including the first metal film forming step and the cap film forming step; and a sample 2 in which a TiN film is formed on a wafer by performing only the substrate processing sequence of FIG6 including the first metal film forming step. The surfaces of the samples 1 and 2 are analyzed by X-ray photoelectron spectroscopy (XPS).

[0112] As shown in FIG. 10(B) and FIG. 10(C), it was confirmed that the peak values ​​of sample 1 and sample 2 were different. By forming a cap film on the TiN film, the TiO component was suppressed, and oxidation of the TiN film was suppressed.

[0113] 11 (A), the substrate processing apparatus 10 of the processing furnace 202b, the substrate processing sequence of FIG. 7 is performed, the W film is formed on the surface of the sample 1 and the sample 2, respectively, for the surface of the sample 1 and the sample 2 XPS analysis.

[0114] As shown in Figure 11(B), the Ti2p intensity of Sample 1 was higher than that of Sample 2, indicating a larger amount of residual TiN film. This indicates that the formation of the cap film suppresses etching of the TiN film during W film formation. Furthermore, as shown in Figures 10(C) and 11(C), the peak of the cap film disappears, indicating that a W film is formed on top of the cap film, thereby removing the cap film.

[0115] Various typical embodiments and examples of the present invention have been described above, but the present invention is not limited to these embodiments and examples and can be used in combination as appropriate.

[0116] 10: Substrate processing equipment 121:Controller 200: Wafer (substrate) 201a, 201b: Processing room 202a, 202b: Treatment furnace

Claims

1. A substrate processing method, characterized by comprising: (a) a step of preparing a substrate, the substrate comprising: a film containing a first metal element, and a film containing a group 13 element or a group 14 element formed on the aforementioned film containing the first metal element by an atomic layer or a number of atomic layers; (b) a step of supplying the aforementioned substrate with a gas containing a second metal element and a fluorine element; and (c) a step of forming a film containing the aforementioned second metal element on the aforementioned substrate by performing (b) while removing at least a portion of the film containing the group 13 element or the aforementioned group 14 element.

2. The substrate processing method as described in claim 1, wherein, Furthermore, in step (d), the process of supplying the first reaction gas to the aforementioned substrate is performed, while in step (c), steps (b) and (d) are carried out.

3. The substrate processing method as described in claim 2, wherein, The first reaction gas mentioned above is a reducing gas.

4. The substrate processing method as described in claim 2, wherein, The first reaction gas mentioned above is a hydrogen-containing gas.

5. The substrate processing method as described in claim 4, wherein, The aforementioned hydrogen-containing gas is hydrogen gas.

6. The substrate processing method as described in claim 2, wherein, The first reaction gas mentioned above is a gas containing silicon and hydrogen.

7. The substrate processing method as described in claim 2, wherein, The first reaction gas mentioned above is a gas containing boron and hydrogen.

8. The substrate processing method as described in claim 2, wherein, It further includes (e) a process of supplying a second reaction gas, which is different from the first reaction gas, to the aforementioned substrate, and (f) by performing (b) and (e) after (c), forming another film containing the aforementioned second metal element on the film containing the aforementioned second metal element.

9. The substrate processing method as described in claim 8, wherein, The first reacting gas mentioned above is the first hydrogen-containing gas, and the second reacting gas mentioned above is the second hydrogen-containing gas.

10. The substrate processing method as described in claim 2, wherein, In (d), the flow rate of the first reactant gas is reduced compared to the flow rate of the gas containing the aforementioned second metallic element, and after a predetermined period, the flow rate of the first reactant gas is changed to a flow rate approximately the same as the flow rate of the gas containing the aforementioned second metallic element.

11. The substrate processing method as described in claim 1, wherein, It further comprises: (g) a process of supplying a gas containing the aforementioned Group 13 element or the aforementioned Group 14 element to the aforementioned substrate for forming a film containing the aforementioned first metal element; and (h) a process of supplying a third reaction gas to the aforementioned substrate, and (i) by performing (g) and (h), forming a film containing the aforementioned Group 13 element or the aforementioned Group 14 element on the film containing the aforementioned first metal element.

12. The substrate processing method as described in claim 11, wherein, In (i), (g) and (h) are repeated n times. In (d), (b) and (d) are repeated m times more than n times.

13. The substrate processing method as described in claim 1, wherein, The thickness of the film containing the aforementioned Group 13 element or the aforementioned Group 14 element in (a) is 0.2 nm or more and 3 nm or less.

14. The substrate processing method as described in claim 1, wherein, The thickness of the film containing the aforementioned Group 13 element or the aforementioned Group 14 element in (a) is 0.2 nm or more and 2 nm or less.

15. The substrate processing method as described in claim 1, wherein, The thickness of the film containing the aforementioned Group 13 element or the aforementioned Group 14 element in (a) is 0.4 nm or more and 1.8 nm or less.

16. A method for manufacturing a semiconductor device, characterized by comprising: (a) a step of preparing a substrate, the substrate comprising: a film containing a first metal element, and a film containing a group 13 element or a group 14 element formed on the aforementioned film containing the first metal element by an atomic layer or a number of atomic layers; (b) a step of supplying the aforementioned substrate with a gas containing a second metal element and a fluorine element; and (c) a step of forming a film containing the aforementioned second metal element on the aforementioned substrate by performing (b), while removing at least a portion of the film containing the group 13 element or the aforementioned group 14 element.

17. A program characterized by performing the following procedures on a substrate processing apparatus by means of a computer: (a) a procedure for preparing a substrate having: a film containing a first metal element, and a film containing a group 13 element or a group 14 element formed on the aforementioned film containing the first metal element by one or more atomic layers; (b) a procedure for supplying the aforementioned substrate with a gas containing a second metal element and a fluorine element; and (c) a procedure for forming a film containing the aforementioned second metal element on the aforementioned substrate by performing (b), while removing at least a portion of the film containing the group 13 element or the aforementioned group 14 element.

18. A substrate processing apparatus, characterized by comprising: a gas supply system for supplying a gas containing a second metal element and a fluorine element and a first reaction gas to a substrate, the substrate comprising: a film containing the first metal element, and a film containing a group 13 element or a group 14 element formed on the film containing the first metal element by one or more atomic layers; and a control unit configured to control the gas supply system to perform: (a) a process for preparing the substrate; (b) a process for supplying the gas containing the second metal element to the substrate; and (c) a process for forming a film containing the second metal element on the substrate by removing at least a portion of the film containing the group 13 element or the group 14 element formed on the film containing the first metal element while performing the process of (b).

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