Semiconductor device manufacturing method, substrate processing apparatus and program

Abstract

The present invention carries out the following steps: step (a), forming a first metal film by supplying a gas containing a first metal and a first reducing gas to a substrate having a recessed portion on its surface multiple times in a manner that they do not mix with each other; step (b), forming a second metal film on the first metal film by supplying a gas containing at least a second metal and a second reducing gas different from the first reducing gas to the substrate multiple times in a manner that they do not mix with each other; and step (c), etching at least the second metal film by supplying an etching gas to the substrate.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a semiconductor device, a substrate processing apparatus and a program. Background Art

[0002] As one of the steps in the manufacturing process of a semiconductor device, a process of filling a recess provided on a surface of a substrate with a metal film is sometimes performed (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-109419 Summary of the invention

[0006] Problems to be solved by the invention

[0007] An object of the present invention is to provide a technique capable of improving the quality and productivity of a process for filling a concave portion provided on a substrate surface with a metal film.

[0008] Means for solving problems

[0009] According to one embodiment of the present invention, there is provided the following technology, which includes the following steps:

[0010] Step (a), forming a first metal film by supplying a gas containing a first metal and a first reducing gas multiple times to a substrate having a recessed portion on a surface thereof in a manner that the gas and the first reducing gas are not mixed with each other;

[0011] Step (b) of forming a second metal film on the first metal film by supplying at least a gas containing a second metal and a second reducing gas different from the first reducing gas to the substrate a plurality of times in a manner that the gas does not mix with each other; and

[0012] In step (c), etching gas is supplied to the substrate to etch at least the second metal film.

[0013] Effects of the Invention

[0014] According to the present invention, the quality and productivity of the process of filling a recessed portion formed on a substrate surface with a metal film can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] [ Figure 1 ] is a schematic diagram of the structure of a vertical processing furnace of a substrate processing device suitable for use in one embodiment of the present invention, and is a diagram showing a processing furnace portion in a longitudinal cross-sectional view.

[0016] [ Figure 2] is a schematic diagram of a vertical processing furnace of a substrate processing device suitable for use in one embodiment of the present invention, Figure 1 The AA line cross-sectional view shows a portion of the processing furnace.

[0017] [ Figure 3 ] is a schematic diagram of the structure of a controller of a substrate processing device suitable for use in one embodiment of the present invention, and is a diagram showing the control system of the controller in the form of a block diagram.

[0018] [ Figure 4 ] is a flow chart showing the substrate processing sequence of one embodiment of the present invention.

[0019] [ Figure 5 ](a) is an enlarged cross-sectional view showing the surface structure of the chip before the first W film is formed, (b) is an enlarged cross-sectional view showing the surface structure of the chip after the first W film is formed, (c) is an enlarged cross-sectional view showing the surface structure of the chip after the second W film is formed on the first W film, (d) is an enlarged cross-sectional view showing the surface structure of the chip during etching, and (e) is an enlarged cross-sectional view showing the surface structure of the chip after etching is completed.

[0020] [ Figure 6 ] is a flowchart showing a variation of the substrate processing sequence of one embodiment of the present invention.

[0021] [ Figure 7 ] is a flowchart showing other variations of the substrate processing sequence of one embodiment of the present invention.

[0022] [ Figure 8 ] is a diagram showing the cross-sectional structure of the main parts of 3D NAND.

[0023] [ Fig. 9 ](a) is a graph showing the measurement results of the total processing time for forming the first W film and the second W film in the embodiment and the comparative example, and (b) is a graph showing the measurement results of the film formation rate of the first W film and the film formation rate of the second W film. DETAILED DESCRIPTION

[0024] <One embodiment of the present invention>

[0025] Below, use Figure 1 to Figure 4 , Figure 5 (a)~ Figure 5 (e) One embodiment of the present invention is described.

[0026] (1) Configuration of substrate processing apparatus

[0027] like Figure 1As shown, the processing furnace 202 has a heater 207 as a heating mechanism (temperature adjustment unit). The heater 207 is cylindrical and is vertically installed by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) the gas by heat.

[0028] A reaction tube 203 is disposed concentrically with the heater 207 inside the heater 207. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC), and is formed into a cylindrical shape with a closed upper end and an open lower end. A processing chamber 201 is formed in the hollow portion of the reaction tube 203. The processing chamber 201 is configured to accommodate a wafer 200 as a substrate.

[0029] In the processing chamber 201, nozzles 249a and 249b are provided so as to penetrate the lower side wall of the reaction tube 203. Gas supply pipes 232a and 232b are connected to the nozzles 249a and 249b, respectively.

[0030] On the gas supply pipes 232a and 232b, mass flow controllers (MFCs) 241a and 241b as flow controllers (flow control units) and valves 243a and 243b as on-off valves are respectively provided in order from the upstream side of the gas flow. Gas supply pipes 232c and 232d are respectively connected to the gas supply pipes 232a and 232b on the downstream side of the valves 243a and 243b. On the gas supply pipes 232c and 232d, MFCs 241c and 241d and valves 243c and 243d are respectively provided in order from the upstream side of the gas flow.

[0031] like Figure 2 As shown, in the annular space between the inner wall of the reaction tube 203 and the wafer 200 in a plan view, nozzles 249a and 249b are respectively provided in a manner of standing upright from the lower part of the inner wall of the reaction tube 203 along the upper part toward the upper side of the arrangement direction of the wafer 200. That is, in the area on the side of the wafer arrangement area where the wafer 200 is arranged and horizontally surrounding the wafer arrangement area, the nozzles 249a and 249b are respectively provided along the wafer arrangement area. Gas supply holes 250a and 250b for supplying gas are respectively provided on the side of the nozzles 249a and 249b. The gas supply holes 250a and 250b are respectively opened in a manner of facing the center of the reaction tube 203, and can supply gas toward the wafer 200. A plurality of gas supply holes 250a and 250b are provided in the range from the lower part to the upper part of the reaction tube 203.

[0032] A gas containing metal elements (atoms) and halogen elements, i.e., a halogen compound, is supplied as a gas (raw material gas) containing the first and second metals from the gas supply pipe 232a via the MFC 241a, the valve 243a, and the nozzle 249a into the processing chamber 201. As the gas containing the first and second metals, for example, tungsten hexafluoride (WF6) gas can be used.

[0033] The etching gas is supplied from the gas supply pipe 232a through the MFC 241a, the valve 243a, and the nozzle 249a into the processing chamber 201. As the etching gas, for example, nitrogen trifluoride (NF3) gas, which is a gas containing a halogen element, can be used.

[0034] A gas consisting of hydrogen (H) element alone (consisting of only H element) is supplied as a first reducing gas (a first reaction gas having reducing properties) from a gas supply pipe 232b via MFC 241b, valve 243b, and nozzle 249b into the processing chamber 201. As the first reducing gas, for example, hydrogen (H2) gas can be used.

[0035] A gas containing H, i.e., a compound containing H and an element other than H (a compound containing H) is supplied from a gas supply pipe 232b via an MFC 241b, a valve 243b, and a nozzle 249b into the processing chamber 201 as a second reducing gas (a second reaction gas having a reducing property) different from the first reducing gas. As the second reducing gas, for example, a monosilane (SiH4, abbreviated as: MS) gas containing H and silicon (Si) can be used.

[0036] Nitrogen (N2) gas as an inert gas is supplied from gas supply pipes 232c and 232d via MFCs 241c and 241d, valves 243c and 243d, gas supply pipes 232a and 232b, and nozzles 249a and 249b into the processing chamber 201. N2 gas functions as a purge gas, a carrier gas, and the like.

[0037] The raw material gas supply system and the etching gas supply system are mainly composed of the gas supply pipe 232a, MFC241a, and valve 243a. The first and second reducing gas supply systems are mainly composed of the gas supply pipe 232b, MFC241b, and valve 243b. The inactive gas supply system is mainly composed of gas supply pipes 232c, 232d, MFC241c, 241d, and valves 243c and 243d. Any or all of the above-mentioned various supply systems can also be collectively referred to as a gas supply system.

[0038] Any or all of the various supply systems mentioned above can be configured in the form of an integrated supply system 248 in which valves 243a to 243d, MFC241a to 241d, etc. are integrated. The integrated supply system 248 is configured to be connected to the gas supply pipes 232a to 232d, respectively, and the supply action of various gases in the gas supply pipes 232a to 232d, that is, the opening and closing action of the valves 243a to 243d, the flow rate adjustment action performed by the MFC241a to 241d, etc., is controlled by the controller 121 described later. The integrated supply system 248 is configured as an integrated unit of an integral type or a separate type, and can be disassembled and assembled as an integrated unit unit relative to the gas supply pipes 232a to 232d, etc., and the integrated supply system 248 can be maintained, replaced, and added as an integrated unit unit.

[0039] An exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201 is connected to the lower side wall of the reaction tube 203. A vacuum pump 246 as a vacuum exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure regulation unit). The APC valve 244 is configured to open and close the valve while the vacuum pump 246 is in operation, thereby enabling vacuum exhaust and vacuum exhaust stop in the processing chamber 201, and further enabling the pressure in the processing chamber 201 to be adjusted by adjusting the valve opening based on the pressure information detected by the pressure sensor 245 while the vacuum pump 246 is in operation. The exhaust system is mainly composed of the exhaust pipe 231, the pressure sensor 245, and the APC valve 244. It is also conceivable to include the vacuum pump 246 in the exhaust system.

[0040] Below the reaction tube 203, a sealing cover 219 as a furnace cover body capable of hermetically closing the lower end opening of the reaction tube 203 is provided. The sealing cover 219 is made of a metal material such as SUS and is formed into a disc shape. On the upper surface of the sealing cover 219, an O-ring 220 as a sealing member abutting against the lower end of the reaction tube 203 is provided. Below the sealing cover 219, a rotating mechanism 267 for rotating the wafer boat 217 described later is provided. The rotating shaft 255 of the rotating mechanism 267 passes through the sealing cover 219 and is connected to the wafer boat 217. The rotating mechanism 267 is configured to rotate the wafer 200 by rotating the wafer boat 217. The sealing cover 219 is configured to be lifted and lowered in the vertical direction by the wafer boat elevator 115 as a lifting mechanism provided outside the reaction tube 203. The boat elevator 115 is configured as a transport device (transport mechanism) that carries the wafer 200 into and out of the processing chamber 201 (transports) by raising and lowering the sealing cap 219 .

[0041] The wafer boat 217 as a substrate support is configured to support multiple wafers 200, for example, 25 to 200 wafers 200, in a horizontal posture and in a state where the centers are aligned with each other in a vertical direction in multiple layers, that is, multiple wafers 200 are arranged at intervals. The wafer boat 217 is made of a heat-resistant material such as quartz, SiC, etc. At the bottom of the wafer boat 217, a heat insulation plate 218 made of a heat-resistant material such as quartz, SiC, etc. is supported in multiple layers in a horizontal posture.

[0042] A temperature sensor 263 as a temperature detector is provided in the reaction tube 203. The temperature in the processing chamber 201 is adjusted to a desired temperature distribution by adjusting the power supply to the heater 207 based on the temperature information detected by the temperature sensor 263. The temperature sensor 263 is provided along the inner wall of the reaction tube 203.

[0043] like Figure 3 As shown, the controller 121 as a control unit (control means) is configured as a computer having a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to be able to exchange data with the CPU 121a via an internal bus 121e. The controller 121 is connected to an input / output device 122 configured as, for example, a touch panel.

[0044] The storage device 121c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. In the storage device 121c, a control program for controlling the action of the substrate processing device, a process recipe recording the steps and conditions of the substrate processing described later, etc., are stored in a readable manner. The process recipe is a combination of a method that enables the controller 121 to execute each step in the substrate processing process described later and obtain a specified result, and functions as a program. Hereinafter, the process recipe, control program, etc. are also collectively referred to as a program. In addition, the process recipe is also referred to as a recipe. In this specification, when the term program is used, sometimes it refers to a recipe alone, sometimes it refers to a control program alone, or sometimes it includes both. RAM121b is configured as a memory area (work area) that temporarily holds programs, data, etc. read by CPU121a.

[0045] The I / O port 121 d is connected to the above-mentioned MFCs 241 a to 241 d , valves 243 a to 243 d , pressure sensor 245 , APC valve 244 , vacuum pump 246 , heater 207 , temperature sensor 263 , rotation mechanism 267 , boat elevator 115 , and the like.

[0046] The CPU 121a is configured to read and execute the control program from the storage device 121c, and read the process from the storage device 121c according to the input of the operation command from the input / output device 122. The CPU 121a is configured to control the flow rate adjustment operation of various gases by the MFCs 241a to 241d, the opening and closing operation of the valves 243a to 243d, the opening and closing operation of the APC valve 244 and the pressure adjustment operation of the APC valve 244 by the pressure sensor 245, the start and stop of the vacuum pump 246, the temperature adjustment operation of the heater 207 by the temperature sensor 263, the rotation and rotation speed adjustment operation of the wafer boat 217 by the rotation mechanism 267, the lifting and lowering operation of the wafer boat 217 by the wafer boat elevator 115, etc. in accordance with the contents of the read process.

[0047] The controller 121 can be configured by installing the above-mentioned program stored in the external storage device 123 in a computer. The external storage device 123 includes, for example, magnetic disks such as HDD, optical disks such as CD, optical magnetic disks such as MO, semiconductor memories such as USB memories, etc. The storage device 121c and the external storage device 123 are configured as a computer-readable recording medium. Hereinafter, these are also collectively referred to as recording media. When the term recording medium is used in this specification, sometimes only the storage device 121c is included alone, sometimes only the external storage device 123 is included alone, or sometimes both are included. It should be noted that the provision of the program to the computer can also be done without using the external storage device 123, but using communication methods such as the Internet and dedicated lines.

[0048] (2) Substrate processing step

[0049] Using the above-mentioned substrate processing apparatus, as one of the steps in the manufacturing process of a semiconductor device, a substrate processing sequence example is used to fill the concave portion of a wafer 200 as a substrate with a tungsten film (W film). Figure 4 , Figure 5 (a)~ Figure 5 (e) In the following description, the operations of the various components constituting the substrate processing apparatus are controlled by the controller 121 .

[0050] Figure 4 In the substrate processing sequence shown, the following steps are performed:

[0051] A step of forming a first metal film (first W film) by supplying WF6 gas as a gas containing a first metal and H2 gas as a first reducing gas to a wafer 200 having a recessed portion multiple times in a manner that the WF6 gas and the H2 gas do not mix with each other;

[0052] a step of forming a second metal film (second W film) on the first W film by supplying at least WF6 gas as a gas containing a second metal and MS gas as a second reducing gas to the wafer 200 a plurality of times in a manner that the gas is not mixed with each other; and

[0053] A step of supplying NF3 gas as an etching gas to the wafer 200 to etch at least the second W film.

[0054] In this specification, when the term "wafer" is used, it sometimes refers to the wafer itself, and sometimes refers to a stack of a wafer and a predetermined layer or film formed on its surface. In this specification, when the term "surface of a wafer" is used, it sometimes refers to the surface of the wafer itself, and sometimes refers to the surface of a predetermined layer, etc. formed on the wafer. In this specification, when it is recorded as "forming a predetermined layer on a wafer", it sometimes refers to directly forming a predetermined layer on the surface of the wafer itself, and sometimes refers to forming a predetermined layer on a layer, etc. formed on a wafer. In this specification, the use of the term "substrate" has the same meaning as the use of the term "wafer".

[0055] (Wafer filling and wafer boat loading)

[0056] A plurality of wafers 200 are loaded (wafer filling) into the wafer boat 217. Then, as Figure 1 As shown, the boat 217 supporting a plurality of wafers 200 is lifted by the boat elevator 115 and carried (boat loading) into the processing chamber 201. In this state, the sealing cap 219 is in a state of sealing the lower end of the reaction tube 203 via the O-ring 220.

[0057] As the wafer 200, for example, a Si substrate composed of single-crystal Si or a substrate having a single-crystal Si film formed on the surface can be used. Figure 5 As shown in (a), a concave portion is provided on the surface of a wafer 200. The bottom of the concave portion is made of single crystal Si, and the side and top of the concave portion are made of an insulating film 200a including a silicon oxide film (SiO film), a silicon nitride film (SiN film), a silicon oxycarbon nitride film (SiOCN film), etc. The surface of the wafer 200, that is, the bottom, side and top surface of the concave portion, may be covered with a titanium nitride film (TiN film) as a barrier film.

[0058] (Pressure regulation and temperature regulation)

[0059] In order to make the space in the processing chamber 201, that is, the space where the wafer 200 exists, to be at a desired pressure (vacuum degree), vacuum exhaust (decompression exhaust) is performed by the vacuum pump 246. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure information. In addition, the wafer 200 in the processing chamber 201 is heated by the heater 207 so that it becomes a desired temperature (film forming temperature). At this time, the state of powering the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the temperature distribution in the processing chamber 201 becomes desired. In addition, the rotation of the wafer 200 by the rotation mechanism 267 is started. The operation of the vacuum pump 246, the heating and rotation of the wafer 200 are all continued at least until the processing of the wafer 200 is completed.

[0060] (First W Film Formation Step)

[0061] Then, the following two steps, namely step 1a and step 2a, are performed in sequence.

[0062] [Step 1a]

[0063] WF6 gas is supplied to the wafer 200 in the processing chamber 201. In this step, the valve 243a is opened to allow the WF6 gas to flow into the gas supply pipe 232a. As for the WF6 gas, the flow rate is adjusted by MFC241a, and it is supplied to the processing chamber 201 through the nozzle 249a, and exhausted from the exhaust pipe 231. At this time, WF6 gas is supplied to the wafer 200 (gas supply step containing the first metal). At this time, the valves 243c and 243d are opened to allow N2 gas to flow into the gas supply pipes 232c and 232d. As for the N2 gas, the flow rate is adjusted by MFC241c and 241d, and it is supplied to the processing chamber 201 through the nozzles 249a and 249b, and exhausted from the exhaust pipe 231. The supply of N2 gas to the processing chamber 201 in the gas supply step containing the first metal may not be implemented.

[0064] The following are examples of processing conditions in this step:

[0065] WF6 gas supply flow rate: 1~5000sccm

[0066] N2 gas supply flow rate (each gas supply pipe): 0~30000sccm

[0067] Gas supply time: 0.01 to 10 seconds, preferably 0.1 to 5 seconds

[0068] Processing temperature (film forming temperature): 200-600°C, preferably 300-500°C

[0069] Processing pressure: 1~3990Pa.

[0070] It should be noted that the expression of a numerical range such as "200 to 600°C" in this specification means that the lower limit and the upper limit are included in the range. Therefore, "200 to 600°C" means "200°C or more and 600°C or less". The same applies to other numerical ranges.

[0071] By supplying WF6 gas to the wafer 200 under the above conditions, a W-containing layer (first W-containing layer) containing fluorine (F) is formed on the wafer 200. The first W-containing layer may be an adsorption layer of WF6 gas, a W layer containing F, or both.

[0072] After the first W-containing layer is formed, the valve 243a is closed to stop the supply of WF6 gas into the processing chamber 201. Then, the processing chamber 201 is evacuated to remove the gas remaining in the processing chamber 201 from the processing chamber 201. At this time, the valves 243c and 243d are opened to supply N2 gas into the processing chamber 201. The N2 gas functions as a purge gas (purge step).

[0073] As the gas containing the first metal, in addition to WF6 gas, other tungsten fluoride-based gases can also be used. In addition, as the gas containing the first metal, tungsten chloride-based gases such as tungsten hexachloride (WCl6) gas, tungsten dichloride (WCl2) gas, tungsten tetrachloride oxygen (WOCl4) gas, tungsten pentachloride azide (Cl5N3W) gas can also be used. This is also the case in step 1b described later.

[0074] As the inert gas, in addition to N 2 gas, a rare gas such as Ar gas, He gas, Ne gas, or Xe gas may be used. This also applies to each step described later.

[0075] [Step 2a]

[0076] After step 1a is completed, H2 gas is supplied to the wafer 200 in the processing chamber 201. In this step, the opening and closing of valves 243b to 243d is controlled by the same steps as the opening and closing control of valves 243a, 243c, and 243d in step 1a. As for H2 gas, the flow rate is adjusted by MFC241b, supplied to the processing chamber 201 through nozzle 249b, and exhausted from exhaust pipe 231. At this time, H2 gas is supplied to the wafer 200 (first reducing gas supply step).

[0077] The following are examples of processing conditions in this step:

[0078] H2 gas supply flow rate: 1~30000sccm

[0079] Gas supply time: 0.05~60 seconds.

[0080] The other treatment conditions are the same as those in step 1a.

[0081] By supplying H2 gas to the wafer 200 under the above conditions, the first W-containing layer formed on the wafer 200 in step 1a can be made to react with H2 gas. That is, F (fluorine group) contained in the first W-containing layer can be made to react with H2 gas. Thus, F in the first W-containing layer that reacts with H can be separated (extracted) from the first W-containing layer. Through this reaction, F is separated from the first W-containing layer, and the first W-containing layer is changed (modified) to the first layer containing W (first W layer). The first W layer becomes a layer composed of W simple substance, that is, a layer with W as the main component.

[0082] When the first W layer is formed, F contained in the first W-containing layer and H2 gas form a gaseous substance containing at least one of F and H during the modification reaction of the first W-containing layer by H2 gas, and the gaseous substance is exhausted from the processing chamber 201 through the exhaust pipe 231. That is, impurities such as F in the first W-containing layer are drawn out from the first W-containing layer or separated from the first W-containing layer, thereby being separated from the first W-containing layer. As a result, the first W layer becomes a layer with less impurities such as F than the first W-containing layer.

[0083] If, for example, MS gas (which is a H-containing gas containing an element other than H element (Si element)) is used as the first reducing gas, Si contained in the MS gas is captured in the first W layer during the modification, and the first W layer may become a high-resistance layer. By using H2 gas containing no elements other than H element in step 2a, the impurity concentration of the first W layer is reduced, and a reduction in the conductivity of the first W layer can be avoided.

[0084] Then, the valve 243b is closed to stop the supply of H2 gas into the processing chamber 201. Then, the processing chamber 201 is evacuated by the same processing steps as those in the purging step of step 1a, and the gas remaining in the processing chamber 201 is removed from the processing chamber 201 (purging step).

[0085] As the first reducing gas, deuterium (D2) gas may be used in addition to H2 gas.

[0086] [Number of times of implementation]

[0087] By performing the cycle of steps 1a and 2a non-simultaneously, i.e., without mixing the WF6 gas and the H2 gas, for a predetermined number of times (m times, where m is an integer greater than 1), it is possible to form a first W film that fills the concave portion of the wafer 200 and covers the upper surface of the insulating film 200a. By alternately supplying the WF6 gas and the H2 gas to form the first W film, it is possible to form the first W film by utilizing a surface reaction rather than a gas phase reaction. As a result, the concave portion can be filled with the first W film without generating a void in the concave portion. It is preferred to repeat this cycle multiple times until the concave portion is filled with the first W film. That is, it is preferred to make the thickness of the first W layer formed in each cycle smaller than the desired film thickness and repeat the above cycle multiple times until the film thickness of the first W film formed by stacking the first W layer reaches the desired film thickness.

[0088] like Figure 5 As shown in (b), a V-shaped concave portion is formed on the upper surface (surface) of the first W film formed on the concave portion of the wafer 200. By repeating the cycle of non-simultaneously performing steps 1a and 1b for a long time, the V-shaped concave portion becomes smaller and eventually disappears, and the surface of the first W film becomes flat. However, the first W film forming step is a step performed for the purpose of filling the concave portion of the wafer 200 with the first W film. Therefore, it is preferred that once the concave portion of the wafer 200 is filled with the first W film, even in the state where a V-shaped concave portion is formed on the surface of the first W film, that is, before the surface of the first W film becomes flat, the second W film forming step is transferred as soon as possible. In other words, the film thickness of the first W film is preferably limited to the thickness required to completely fill the concave portion of the wafer 200 with the first W film.

[0089] The thickness of the first W film is preferably thicker than the thickness of the first W film remaining after the etching step described later, that is, the thickness of the first W film finally remaining in the recess of the wafer 200 (hereinafter also referred to as the final thickness). The thickness of the first W film is preferably, for example, 1.1 to 1.2 times the final thickness.

[0090] When the film thickness of the first W film is less than 1.1 times the above-mentioned final thickness, there is a deviation in the processing accuracy of the concave portion of the wafer 200, and therefore, there is a case where the first W film cannot completely fill the concave portion of the wafer 200. For example, there is a case where the lower end of the above-mentioned V-shaped concave portion is located in the concave portion of the wafer 200. In addition, when etching is excessively performed, a W film of the desired thickness is not left on the wafer 200, which sometimes causes a decrease in the quality of the W film. By making the film thickness of the first W film more than 1.1 times the above-mentioned final thickness, the problem described here can be eliminated. When the film thickness of the first W film exceeds 1.2 times the above-mentioned final thickness, the total film formation time of the W film formed by stacking the first W film and the second W film becomes longer, and there is a case where the productivity of substrate processing is reduced. By making the film thickness of the first W film less than 1.2 times the above-mentioned final thickness, the total film formation time of the W film can be shortened, thereby improving the productivity of substrate processing.

[0091] When the width of the concave portion of the wafer 200 is, for example, 20 nm, if the thickness of the first W film is 10 nm, the concave portion can be filled with the first W film. However, as described above, considering the processing accuracy variation of the concave portion of the wafer 200, it is preferred that the thickness of the first W film is greater than 10 nm, for example, 11 to 12 nm.

[0092] (Second W Film Formation Step)

[0093] Then, the following two steps, namely, steps 1b and 2b, are performed in sequence.

[0094] [Step 1b]

[0095] After the first W film formation step is completed, WF6 gas is supplied to the wafer 200 in the processing chamber 201. In this step, the opening and closing of the valves 243a, 243c, and 243d are controlled by the same steps as the opening and closing control of the valves 243a, 243c, and 243d in step 1a. As for the WF6 gas, the flow rate is adjusted by MFC241a, and it is supplied to the processing chamber 201 through the nozzle 249a and exhausted from the exhaust pipe 231. At this time, WF6 gas is supplied to the wafer 200 (gas supply step containing the second metal).

[0096] As the processing conditions in this step, the same processing conditions as those in step 1a can be exemplified.

[0097] By supplying WF6 gas to the wafer 200 under the above conditions, a W-containing layer containing F (second W-containing layer) is formed on the wafer 200. The second W-containing layer may be an adsorption layer of WF6 gas, a W layer containing F, or both.

[0098] After the second W-containing layer is formed, the valve 243a is closed to stop the supply of WF6 gas into the processing chamber 201. Then, the processing chamber 201 is evacuated by the same processing steps as those in the purging step of step 1a, and the residual gas in the processing chamber 201 is removed from the processing chamber 201 (purging step).

[0099] As the gas containing the second metal, the same gas as the gas containing the first metal described above can be used. As the gas containing the first metal and the gas containing the second metal, the same gas can be used, or different gases can be used.

[0100] [Step 2b]

[0101] After step 1b is completed, MS gas is supplied to the wafer 200 in the processing chamber 201. In this step, the opening and closing of valves 243b to 243d is controlled by the same steps as the opening and closing control of valves 243a, 243c, and 243d in step 1a. As for MS gas, the flow rate is adjusted by MFC241b, supplied to the processing chamber 201 through nozzle 249b, and exhausted from exhaust pipe 231. At this time, MS gas is supplied to the wafer 200 (second reducing gas supply step).

[0102] The following are examples of processing conditions in this step:

[0103] MS gas supply flow rate: 1~3000sccm

[0104] Gas supply time: 0.01 to 30 seconds.

[0105] The other treatment conditions are the same as those in step 1a.

[0106] By supplying MS gas to the wafer 200 under the above conditions, the second W-containing layer formed on the wafer 200 in step 1b can be reacted with the MS gas. That is, the F contained in the second W-containing layer can be reacted with the MS gas. Thus, the F in the second W-containing layer that reacts with MS can be separated (extracted) from the second W-containing layer. Through this reaction, F is separated from the second W-containing layer, and the second W-containing layer is changed (modified) to a second layer containing W (second W layer). The second W layer becomes a layer composed of a single substance of W, that is, a layer with W as the main component.

[0107] When the second W layer is formed, F contained in the second W-containing layer and the MS gas form a gaseous substance containing at least any one of F, H and Si in the modification reaction process of the second W-containing layer by the MS gas, and are exhausted from the processing chamber 201 through the exhaust pipe 231. That is, the impurities such as F in the second W-containing layer are drawn out or separated from the second W-containing layer, and are separated from the second W-containing layer. As a result, the second W layer becomes a layer with less impurities such as F than the second W-containing layer.

[0108] The bond energy of Si-H bond of MS gas used in step 2b is lower than the bond energy of HH bond of H2 gas used in step 2a. That is, the thermal decomposition temperature of MS gas is lower than that of H2 gas (it is easy to decompose). Therefore, by using MS gas as the second reducing gas, the film formation rate of the second W film can be increased compared with the case of using H2 gas as the second reducing gas.

[0109] Then, valve 243b is closed to stop the supply of MS gas into the processing chamber 201. Then, the processing chamber 201 is evacuated by the same processing steps as those in the purging step of step 1a, and the gas remaining in the processing chamber 201 is removed from the processing chamber 201 (purging step).

[0110] [Number of times the regulations are implemented]

[0111] By performing steps 1b and 2b non-simultaneously, i.e. without mixing the WF6 gas and the MS gas, the cycle is repeated for a predetermined number of times (n times, where n is an integer greater than 1), so that Figure 5 As shown in (c), a second W film can be formed on the first W film. That is, a W film (hereinafter, also referred to as the W film) of a specified film thickness formed by stacking the first W film and the second W film in sequence can be formed on the wafer 200. By repeating the cycle of steps 1b and 2b non-simultaneously, the V-shaped concave portion eventually disappears, and the upper surface (surface) of the second W film, that is, the upper surface of the W film becomes flat. It is preferred to repeat the cycle multiple times until the surface of the second W film becomes flat. That is, it is preferred to make the thickness of the second W layer formed in each cycle less than the desired film thickness and repeat the above cycle multiple times until the film thickness of the second W film formed by stacking the second W layer becomes the desired film thickness and the surface of the second W film becomes flat.

[0112] (Etching Step)

[0113] After the second W film formation step is completed, NF3 gas is supplied to the wafer 200 in the processing chamber 201. In this step, the opening and closing control of the valves 243a, 243c, and 243d is performed using the same steps as the opening and closing control of the valves 243a, 243c, and 243d in step 1a. As for the NF3 gas, the flow rate is adjusted by MFC241a, and it is supplied to the processing chamber 201 through the nozzle 249a and exhausted from the exhaust pipe 231. At this time, NF3 gas is supplied to the wafer 200 (etching gas supply step).

[0114] The following are examples of processing conditions in this step:

[0115] NF3 gas supply flow rate: 1~10000sccm

[0116] Gas supply time: 1 to 1800 seconds, preferably 1 to 1200 seconds

[0117] Processing temperature: 300-600°C, preferably 400-500°C.

[0118] The other treatment conditions are the same as those in step 1a.

[0119] By supplying NF3 gas to the wafer 200 under the above-mentioned conditions, a part of the W film formed on the wafer 200, that is, at least the second W film can be etched (etching step, etch-back step).

[0120] Although the first W film and the second W film have different impurity concentrations in the films, they are substantially the same film. Therefore, the etching rates of the first W film and the second W film relative to the NF3 gas are substantially equal. As a result, the in-plane uniformity of the wafer during etching (hereinafter also referred to as in-plane uniformity) can be improved. For example, Figure 5 As shown in (d), even if the first W film and the second W film are mixed on the surface (etched surface) of the wafer 200 during etching, etching can be performed at a substantially uniform rate over the entire region in the plane (surface) of the wafer 200. As described above, the surface of the second W film, that is, the surface of the W film, becomes a flat surface. Therefore, by etching at a substantially uniform rate over the entire region in the plane of the wafer 200, the surface of the first W film that is finally left in the concave portion of the wafer 200 after etching can be made flat.

[0121] The W film on the wafer 200 is etched only by a desired amount, such as Figure 5As shown in (e), the surface of the W film becomes a flat surface consisting of only the first W film, and then the valve 243a is closed to stop the supply of NF3 gas into the processing chamber 201. Then, the processing chamber 201 is vacuum-exhausted by the same processing steps as those in the purge step of step 1a, and the gas remaining in the processing chamber 201 is removed from the processing chamber 201 (purge step).

[0122] As the etching gas, in addition to the NF3 gas, chlorine fluoride (HF) gas, chlorine trifluoride (ClF3) gas, fluorine (F2) gas, etc. can also be used.

[0123] (Post-purge and atmospheric pressure recovery)

[0124] After the etching step is completed, N2 gas is supplied from the gas supply pipes 232c and 232d to the processing chamber 201, and the gas is exhausted from the exhaust pipe 231. Thus, the processing chamber 201 is purged, and the gas, reaction by-products, etc. remaining in the processing chamber 201 are removed from the processing chamber 201 (post-purging). Then, the atmosphere in the processing chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure in the processing chamber 201 is restored to normal pressure (atmospheric pressure recovery).

[0125] (Wafer boat unloading and wafer removal)

[0126] Then, the sealing cover 219 is lowered by the wafer boat elevator 115, the lower end of the reaction tube 203 is opened, and the processed wafers 200 are carried out from the lower end of the reaction tube 203 to the outside of the reaction tube 203 in a state supported by the wafer boat 217 (wafer boat unloading). After the processed wafers 200 are carried out to the outside of the reaction tube 203, they are taken out from the wafer boat 217 (wafer removal).

[0127] (3) Effects of this embodiment

[0128] According to the present embodiment, one or more of the following effects can be obtained.

[0129] (a) By forming a first W film by using WF6 gas and H2 gas to fill the concave portion of the wafer 200, and then forming a second W film by using WF6 gas and MS gas until the surface becomes flat, the total productivity of the W film can be improved. That is, since the modification rate of the second W film using MS gas having a lower thermal decomposition temperature than that of the first W film using H2 gas is greater, in this embodiment, the productivity of the W film formation process can be improved compared to the case where the W film is formed using only H2 gas as a reducing gas. As a result, the productivity of the W film filling process in the concave portion provided on the surface of the wafer 200 can be improved.

[0130] (b) By using a gas consisting of only H element, i.e., a gas containing no other elements other than H element such as Si and boron (B), as the first reducing gas, it is possible to prevent impurities brought by the first reducing gas from being mixed into the first W film. As a result, the impurity concentration of the first W film can be reduced, and the conductivity of the first W film can be prevented from being reduced. That is, the first W film becomes a film with high quality, and the quality of the W film filling process in the concave portion of the wafer 200 can be improved.

[0131] (c) By making the first W film that ultimately remains on the wafer 200 after etching a high-quality film with a low impurity concentration, and making the second W film that is removed by etching a film with a high impurity concentration but a high film formation rate, the quality and productivity of the W film filling process in the recessed portion of the wafer 200 can be improved.

[0132] (d) By making the first W film and the second W film have substantially the same etching rate, the in-plane uniformity of the etching process can be improved, and the surface of the W film finally remaining in the concave portion of the wafer 200 can be made flat.

[0133] (e) By forming the first W film by alternately supplying a gas containing a first metal (WF6 gas) and a first reducing gas (H2 gas) to the wafer 200, the first W film can be formed by surface reaction rather than gas phase reaction. As a result, compared with the case of using a simultaneous supply method of supplying WF6 gas and H2 gas to the wafer 200 at the same time, the step coverage (step coverage characteristics) of the first W film can be improved. Thus, the generation of voids in the recess can be avoided. As a result, the recess can be completely filled with the first W film, that is, in a state without voids. By alternately supplying WF6 gas and H2 gas to form the first W film, the first W film can be used to fill the recess without generating voids in the recess.

[0134] (f) By forming the second W film by alternately supplying the gas containing the second metal (WF6 gas) and the second reducing gas (MS gas) to the wafer 200, the step coverage characteristics of the second W film can be improved compared with the case of simultaneously supplying the WF6 gas and the MS gas to the wafer 200. Thus, the controllability of the film thickness control of the second W film can be improved.

[0135] (g) By forming a second film having a stress value lower than that of the first W film on the first W film, that is, a second W film having an internal stress lower than that of the first W film (low film stress), the stress applied to the first W film can be reduced, and deformation, collapse, etc. of the first W film can be suppressed during etching.

[0136] (h) The above-mentioned effects can also be obtained when the above-mentioned raw material gas other than WF6 gas is used, when the above-mentioned etching gas other than NF3 gas is used, and when an inert gas other than N2 gas is used.

[0137] (4) Modification

[0138] This embodiment can be modified as follows. In addition, these modifications can be combined arbitrarily. Unless otherwise specified, the processing steps and processing conditions in each step of each modification are the same as the processing steps and processing conditions in each step of the above-mentioned substrate processing sequence.

[0139] (Variant 1)

[0140] As the second reducing gas, diborane (B2H6, abbreviated as DB) gas, dichlorosilane (SiH2Cl2, abbreviated as DCS) gas, disilane (Si2H6, abbreviated as DS) gas, ammonia (NH3) gas, etc. can be used. When using these gases, the same Figure 4 The same effect is achieved in the order of substrate processing shown.

[0141] It should be noted that, when DB gas is used as the second reducing gas, the processing conditions in step 2b are exemplified as follows:

[0142] DB gas supply flow rate: 1~20000sccm

[0143] Gas supply time: 0.1~60 seconds

[0144] Processing temperature: 150~400℃.

[0145] The other treatment conditions are the same as those in step 1a. In this case, it is preferable that the treatment temperature in step 1b is the same as that in step 2b.

[0146] In addition, when DCS gas is used as the second reducing gas, the processing conditions in step 2b are exemplified as follows:

[0147] DCS gas supply flow rate: 1~2000sccm

[0148] Gas supply time: 0.1~60 seconds

[0149] Processing temperature: 300~600℃.

[0150] The other treatment conditions are the same as those in step 1a. In this case, it is preferable that the treatment temperature in step 1b is the same as that in step 2b.

[0151] In addition, when DS gas is used as the second reducing gas, the processing conditions in step 2b are exemplified as follows:

[0152] DS gas supply flow rate: 1~2000sccm

[0153] Gas supply time: 0.1~60 seconds

[0154] Processing temperature: 200~400℃.

[0155] The other treatment conditions are the same as those in step 1a. In this case, it is preferable that the treatment temperature in step 1b is the same as that in step 2b.

[0156] In addition, when NH3 gas is used as the second reducing gas, the processing conditions in step 2b are exemplified as follows:

[0157] NH3 gas supply flow rate: 1~20000sccm

[0158] Gas supply time: 0.1~60 seconds

[0159] Processing temperature: 300~600℃.

[0160] The other treatment conditions are the same as those in step 1a. In this case, it is preferable that the treatment temperature in step 1b is the same as that in step 2b.

[0161] In addition, as the second reducing gas, two or more kinds of the above-mentioned reducing gases may be used.

[0162] (Variant 2)

[0163] In the above embodiment, the case where the metal element contained in the gas containing the first and second metals is W is described. However, the present invention is not limited to such a mode. For example, even if the metal element contained in the gas containing the first and second metals is a transition metal element such as copper (Cu), cobalt (Co), titanium (Ti), molybdenum (Mo), tantalum (Ta), ruthenium (Ru), hafnium (Hf), zirconium (Zr), or a typical metal element such as aluminum (Al), the present invention can also be appropriately applied. In this modified example, the same effect as the above embodiment can also be obtained.

[0164] (Variant 3)

[0165] In the above embodiment, an example of forming a film composed of a W single substance on the wafer 200 is described. However, the present invention is not limited to such a method. For example, even when a film containing a metal element such as a tungsten nitride (WN) film, a tungsten oxide (WO) film, a tungsten oxynitride (WON) film, a titanium nitride (TiN) film, etc. is formed on the wafer 200, the present invention can also be appropriately applied. In the case of forming these films, in at least one of the steps of forming the first metal film and forming the second metal film, the following cycle can be performed a predetermined number of times, and the cycle includes a step of supplying a raw material gas to the wafer 200 and a step of supplying a reducing gas to the wafer 200, and also includes a step of supplying a nitriding gas to the wafer 200 and a step of supplying an oxidizing gas to the wafer 200. As the nitriding gas, for example, NH3 gas can be used, and as the oxidizing gas, for example, oxygen (O2) gas can be used.

[0166] (Variant 4)

[0167] The first metal film and the second metal film may be different films. In this case, it is preferable that the etching rates of the first metal film and the second metal film are close to each other.

[0168] The metal elements contained in the gas containing the first and second metals may be different elements. Figure 6 As shown in the substrate processing sequence, WF6 gas is used as the gas containing the first metal to form a W film as the first metal film, and titanium tetrachloride (TiCl4) gas is used as the gas containing the second metal to form a Ti film as the second metal film. In this variant, the same effect as the above embodiment can also be obtained.

[0169] A film composed of a metal single substance may be formed as the first metal film, and a film containing a metal element may be formed as the second metal film. For example, a W film may be formed as the first metal film, and a WN film, a WO film, a TiN film, or the like may be formed as the second metal film. In addition, for example, it is more preferable to form a W film as the first metal film, and to form a TiN film or a WN film having a film stress smaller than that of the W film as the second metal film.

[0170] (Variant 5)

[0171] In the second W film forming step, Figure 7 In this modification, the same substrate processing sequence as shown in FIG. Figure 4The same effect as the substrate processing sequence shown in FIG. 1 is obtained by forming the second W film by the simultaneous supply method, thereby increasing the film forming rate of the second W film compared to the case of using the alternating supply method. As a result, the total film forming rate of the W film formed by stacking the first W film and the second W film can be further increased. However, as described above, it is preferable to use the alternating supply method to form the second W film from the perspective of improving the controllability of the film thickness control of the second W film.

[0172] (Variant 6)

[0173] At once Figure 4 In terms of the substrate processing sequence shown in FIG. 1 , in step 2b, the NF3 gas is continuously supplied, but the NF3 gas may also be supplied intermittently multiple times. Figure 4 The same effect is achieved in the order of substrate processing shown.

[0174] (Variant 7)

[0175] In step 2b, O2 gas may be supplied to the wafer 200 together with NF3 gas (simultaneously). In this case, the supply of O2 gas may be started simultaneously with the supply of NF3 gas, or the supply of O2 gas may be started before the supply of NF3 gas. In addition, the supply of NF3 gas and the supply of O2 gas may be stopped simultaneously, or the supply of NF3 gas may be stopped before the supply of O2 gas. In this variant, the same Figure 4 The same effect as the substrate processing sequence shown in the figure is achieved. In addition, by circulating O2 gas during the etching step, even if a film other than the etching target film is removed by the etching gas, it can be quickly oxidized. As a result, the reaction between the film other than the etching target film and the etching gas can be minimized.

[0176] <Other Implementation Methods>

[0177] The embodiments of the present invention have been specifically described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0178] In the above embodiment, an example in which the reaction tube has a single tube structure is described, but the reaction tube may have a double tube structure including an inner reaction tube (inner tube) and an outer reaction tube (outer tube) provided outside the inner reaction tube.

[0179] In the above-mentioned embodiment, an example is described in which a series of steps from the first W film forming step to the etching step are performed in the same processing chamber 201 (in-situ). However, the present invention is not limited to such a method. For example, the first and second W film forming steps and the etching step may be performed in different processing chambers (in ex-situ). In addition, for example, the first W film forming step and a series of step groups after the second W film forming step may be performed in ex-situ. In addition, for example, each step may be performed in ex-situ. Among them, when all the steps are performed in-situ, the chip 200 will not be exposed to the atmosphere in the middle, and the chip 200 can be kept in a clean atmosphere and processed consistently, so that a stable film forming process can be performed.

[0180] The above-mentioned embodiments, variations, etc. can be applied to a metal film forming process performed as a process of manufacturing a flash memory (which is a nonvolatile semiconductor storage device (nonvolatile memory)). Hereinafter, the structure of the main part of a NAND flash memory (among which, a three-dimensional NAND flash memory (hereinafter also referred to as 3D NAND)) as a type of flash memory manufactured by applying the above-mentioned embodiments, variations, etc. will be described with reference to the following. Figure 8 It should be noted that, here, for convenience, a part of the films and structures constituting 3D NAND will be described, and description of other films and structures will be omitted.

[0181] like Figure 8 As shown in FIG. 1 , a multilayer stacked film is formed by alternately stacking an insulating film 102 such as a SiO film and a metal film 104 such as a W film on the surface of a wafer 200. Here, an example is shown in which the bottom layer and the top layer are the insulating film 102. The metal film 104 functions as a control gate. That is, the metal film 104 that functions as a control gate is formed between the insulating films 102 adjacent to each other. Figure 8 In the figure, for convenience, an example in which the number of stacked layers is 8 is shown, but the present invention is not limited to such a structure. A channel hole is formed in the multi-layer stacked film. In the channel hole, an insulating film 108 composed of three layers of ONO film, i.e., SiO film / SiN film / SiO film, and a channel polycrystalline Si film 109 are formed in sequence from the outer peripheral side. The insulating film 108 and the channel polycrystalline Si film 109 are each formed in a cylindrical shape. The rest of the channel hole, i.e., the recess formed by the channel polycrystalline Si film 109 is filled with an insulating film (filling insulating film) 110 such as SiO film. Between the inner wall surface of the channel hole and the insulating film 108, a protective film 107 composed of a metal oxide film such as SiO film or aluminum oxide (AlO) can be formed to protect the insulating film 108.

[0182] Furthermore, the above-described embodiments, modifications, and the like can also be applied to a process of forming a metal film for a word line which is performed as one of the steps in the manufacturing process of a dynamic random access memory (DRAM) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

[0183] Preferably, the process used in the substrate processing is prepared separately according to the processing content, and is pre-stored in the storage device 121c via the electrical communication line and the external storage device 123. In addition, when starting the substrate processing, it is preferred that the CPU 121a appropriately selects a suitable process from the multiple processes stored in the storage device 121c according to the substrate processing content. In this way, it is possible to form films of various film types, composition ratios, film qualities, and film thicknesses with good reproducibility in one substrate processing device. In addition, the burden on the operator can be reduced, and the processing can be started quickly while avoiding operating errors.

[0184] The above process is not limited to the case of newly making, and for example, it can also be prepared by changing an existing process already installed in a substrate processing device. When changing the process, the changed process can also be installed in the substrate processing device via an electrical communication line or a recording medium recording the process. In addition, the input / output device 122 of the existing substrate processing device can be operated to directly change the existing process installed in the substrate processing device.

[0185] In the above embodiment, an example of forming a film using a batch-type substrate processing device that processes multiple substrates at a time is described. The present invention is not limited to the above embodiment, and for example, a single-sheet substrate processing device that processes one or more substrates at a time can also be appropriately used to form a film. In addition, in the above embodiment, an example of forming a film using a substrate processing device having a hot wall type processing furnace is described. The present invention is not limited to the above embodiment, and can also be appropriately applied to a case where a film is formed using a substrate processing device having a cold wall type processing furnace.

[0186] When these substrate processing apparatuses are used, film formation can be performed according to the same processing steps and processing conditions as those in the above-mentioned embodiment and modification examples, and the same effects as those can be obtained.

[0187] In addition, the above-mentioned embodiments, modifications, etc. can be used in combination as appropriate. The processing steps and processing conditions in this case can be, for example, the same as the processing steps and processing conditions in the above-mentioned embodiment.

[0188] Example

[0189] Hereinafter, examples will be described.

[0190] As an example, using Figure 1 The substrate processing device shown in FIG. Figure 4 The W film is formed on the wafer by the substrate processing sequence shown in FIG. The processing conditions are set to predetermined conditions within the range of the processing conditions in the above-mentioned embodiment.

[0191] As a comparative example, Figure 1 The substrate processing apparatus shown forms a W film on a wafer by performing the first W film forming step. In the comparative example, the second W film forming step is not performed. Other processing conditions are the same as the processing steps and processing conditions in the embodiment.

[0192] Then, the total processing time of the formation process of the first W film and the second W film was measured for the embodiment and the comparative example. The results are shown in Fig. 9 (a) According to Fig. 9 (a), it can be seen that the total processing time of the formation of the first W film and the second W film in the embodiment is shorter than the total processing time in the comparative example. Next, the film formation rate of the first W film in the first W film formation step and the film formation rate of the second W film in the second W film formation step were measured respectively. The results are shown in Fig. 9 (b) According to Fig. 9 (b), it can be seen that the film forming rate of the second W film is greater than the film forming rate of the first W film. Fig. 9 (a) (b) It can be seen that by performing the second W film forming step, the productivity of the substrate processing in which the recessed portion of the wafer is filled with the W film can be improved.

[0193] Description of Reference Numerals

[0194] 200 Wafer (substrate)

Claims

1. A method for manufacturing a semiconductor device, comprising the following steps: Step (a) is to form a first metal film by supplying a gas containing a first metal and a first reducing gas multiple times to a substrate having a concave portion on a surface in a manner that the gas and the first reducing gas are not mixed with each other, thereby filling the concave portion. The first reducing gas is a gas composed of a single substance of hydrogen or a single substance of deuterium; Step (b) of forming a second metal film on the first metal film by supplying at least a gas containing a second metal and a second reducing gas different from the first reducing gas to the substrate multiple times in a manner that the gas does not mix with each other; step (c), supplying an etching gas to the substrate to etch the second metal film and to etch an upper portion of the first metal film, In the production method, step (a) and step (b) are performed sequentially. Step (c) is performed after step (a) and step (b). In the step (a), the thickness of the first metal film before the step (c) is set to be 1.1 to 1.2 times the thickness of the first metal film remaining after the step (c).

2. The method for manufacturing a semiconductor device according to claim 1, wherein: The gas containing the first metal and the gas containing the second metal are halogen compounds, and the second reducing gas is a compound containing hydrogen.

3. The method for manufacturing a semiconductor device according to claim 2, wherein: The second reducing gas is a compound in which the bonding energy between the elements constituting the second reducing gas is smaller than the bonding energy between the hydrogen elements.

4. The method for manufacturing a semiconductor device according to claim 1, wherein: The first metal film and the second metal film have substantially equal etching rates with respect to the etching gas.

5. The method for manufacturing a semiconductor device according to claim 3, wherein: The first metal film and the second metal film have substantially equal etching rates with respect to the etching gas.

6. The method for manufacturing a semiconductor device according to claim 1, wherein: The second metal film has a stress value lower than that of the first metal film.

7. The method for manufacturing a semiconductor device according to claim 1, wherein: The metal element contained in the gas containing the first metal and the metal element contained in the gas containing the second metal are the same element.

8. The method for manufacturing a semiconductor device according to claim 7, wherein: The metal element is any one of tungsten, molybdenum, copper and cobalt.

9. The method for manufacturing a semiconductor device according to claim 1, wherein: The metal elements contained in the gas containing the first metal and the metal elements contained in the gas containing the second metal are different elements.

10. A method for manufacturing a semiconductor device, comprising the following steps: Step (a) is to form a first metal film by supplying a gas containing a first metal and a first reducing gas multiple times to a substrate having a concave portion on a surface in a manner that the gas and the first reducing gas are not mixed with each other, thereby filling the concave portion. The first reducing gas is a gas composed of a single substance of hydrogen or a single substance of deuterium; step (d) of forming a second metal film on the first metal film by simultaneously supplying to the substrate at least a gas containing a second metal and a second reducing gas different from the first reducing gas; and step (c), supplying an etching gas to the substrate to etch the second metal film and to etch an upper portion of the first metal film, In the production method, step (a) and step (d) are performed in sequence. Step (c) is performed after step (a) and step (d). In the step (a), the thickness of the first metal film before the step (c) is set to be 1.1 to 1.2 times the thickness of the first metal film remaining after the step (c).

11. A substrate processing method comprising the following steps: Step (a) is to form a first metal film by supplying a gas containing a first metal and a first reducing gas multiple times to a substrate having a concave portion on a surface in a manner that the gas and the first reducing gas are not mixed with each other, thereby filling the concave portion. The first reducing gas is a gas composed of a single substance of hydrogen or a single substance of deuterium; Step (b) of forming a second metal film on the first metal film by supplying at least a gas containing a second metal and a second reducing gas different from the first reducing gas to the substrate a plurality of times in a manner that the gas does not mix with the first reducing gas; and step (c), supplying an etching gas to the substrate to etch the second metal film and to etch an upper portion of the first metal film, In the substrate processing method, step (a) and step (b) are performed in sequence. Step (c) is performed after step (a) and step (b). In the step (a), the thickness of the first metal film before the step (c) is set to be 1.1 to 1.2 times the thickness of the first metal film remaining after the step (c).

12. A substrate processing device comprising: a processing chamber for substrates to be processed; A gas supply system supplies a gas containing a first metal, a gas containing a second metal, a first reducing gas, a second reducing gas different from the first reducing gas, and an etching gas to the substrate in the processing chamber, wherein: The first reducing gas is a gas consisting of a single substance of hydrogen or a single substance of deuterium; and a control unit configured to control the gas supply system to perform the following process in the process chamber: process (a) of forming a first metal film in a manner of filling the concave portion by supplying the gas containing the first metal and the first reducing gas to the substrate having the concave portion on the surface a plurality of times in a manner that the gas and the first reducing gas are not mixed with each other; Process (b), forming a second metal film on the first metal film by supplying at least the gas containing the second metal and the second reducing gas to the substrate multiple times in a manner that they are not mixed with each other; process (c), etching the second metal film and etching the upper part of the first metal film by supplying an etching gas to the substrate, wherein process (a) and process (b) are performed in sequence, process (c) is performed after process (a) and process (b), and in process (a), the thickness of the first metal film before process (c) is made not less than 1.1 times and not more than 1.2 times the thickness of the first metal film remaining after process (c).

13. A computer-readable recording medium having a program recorded thereon for causing a substrate processing apparatus to execute the following steps in a processing chamber of the substrate processing apparatus through a computer: Step (a), by alternately supplying a gas containing a first metal and a first reducing gas to a substrate having a concave portion on a surface multiple times in a manner that the gas does not mix with each other, thereby forming a first metal film in a manner that fills the concave portion, wherein: The first reducing gas is a gas composed of a single substance of hydrogen or a single substance of deuterium; Step (b), forming a second metal film on the first metal film by supplying at least a gas containing a second metal and a second reducing gas different from the first reducing gas to the substrate multiple times in a manner that the gas does not mix with each other; Step (c), etching the second metal film and etching an upper portion of the first metal film by supplying an etching gas to the substrate; as well as Steps (a) and (b) are performed sequentially in such a manner that in step (a), the thickness of the first metal film before performing step (c) is greater than 1.1 times and less than 1.2 times the thickness of the first metal film remaining after performing step (c), and step (c) is performed after steps (a) and (b).

Images