JP6030746B2 - Semiconductor device manufacturing method, substrate processing apparatus, program, and recording medium - Google Patents

Description

  The present invention relates to a semiconductor device manufacturing method, a substrate processing apparatus, and a program including a step of forming a thin film on a substrate.

As a process of manufacturing a semiconductor device (device), a process of supplying a source gas containing a metal element and fluorine (F) to the substrate, a process of supplying a reactive gas having a reducing property to the substrate, By alternately performing the steps, a step of forming a film containing a metal element over the substrate may be performed. For example, by alternately performing a process of supplying hexafluorotungsten (WF ₆ ) gas to the substrate and a process of supplying diborane (B ₂ H ₆ ) gas to the substrate, tungsten is formed on the substrate. (W) A film can be formed.

However, when a film containing a metal element is formed by the above-described method, a substrate surface, a thin film, or the like, which is a base for film formation, may be affected by a ligand of the metal element contained in the source gas, that is, F. For example, when a W film is formed by the above-described method using a silicon (Si) -containing film or a silicon wafer as a film formation base, the film formation base may be etched by F contained in the WF ₆ gas. When the film formation base is etched, the formed W film is easily peeled off from the film formation base. For example, when an insulating film such as an aluminum oxide film (AlO film) or a hafnium oxide film (HfO film) is used as a base for film formation and a W film is formed by the above-described method, F contained in WF ₆ gas is contained in the insulating film. May be diffused to reduce the insulating properties of the insulating film.

  An object of the present invention is to reduce the influence of a base of film formation when a film containing a metal element is formed on a substrate.

According to one aspect of the invention,
A step of supplying a first source gas which is an inorganic gas containing a metal element and containing no fluorine to the substrate; and a step of supplying a first reactive gas having reducibility to the substrate. Forming a first film containing the metal element on the substrate by performing a cycle including the predetermined number of times;
A cycle including a step of supplying a second source gas containing the metal element and fluorine to the substrate and a step of supplying a second reactive gas having a reducing property to the substrate is performed a predetermined number of times. And forming a second film containing the metal element on the first film;
By performing the above, there is provided a method for manufacturing a semiconductor device including a step of forming a film containing the metal element in which the first film and the second film are stacked on the substrate.

According to another aspect of the invention,
A processing chamber for accommodating the substrate;
A first source gas supply system that supplies a first source gas that is an inorganic gas containing a metal element and not containing fluorine into the processing chamber;
A second source gas supply system for supplying a second source gas containing the metal element and fluorine into the processing chamber;
A first reactive gas supply system for supplying a reducing first reactive gas into the processing chamber;
A second reactive gas supply system for supplying a second reactive gas having reducing properties into the processing chamber;
By performing a predetermined number of cycles including a process of supplying the first source gas to the substrate in the processing chamber and a process of supplying the first reaction gas to the substrate in the processing chamber. A process for forming a first film containing the metal element on the substrate, a process for supplying the second source gas to the substrate in the process chamber, and a process for supplying the second source gas to the substrate in the process chamber. And a process of forming the second film containing the metal element on the first film by performing a cycle including the process of supplying the second reaction gas a predetermined number of times. The first source gas supply system and the second source gas supply system are formed on the substrate so as to form a film containing the metal element formed by laminating the first film and the second film. , Controlling the first reaction gas supply system and the second reaction gas supply system And so that made the control unit,
A substrate processing apparatus is provided.

According to yet another aspect of the invention,
A procedure of supplying a first source gas, which is an inorganic gas containing a metal element and not containing fluorine, to a substrate in the processing chamber, and a first reactive gas having a reducing property to the substrate in the processing chamber And a step of forming a first film containing the metal element on the substrate by performing a cycle including a predetermined number of times, and
A procedure for supplying a second source gas containing the metal element and fluorine to the substrate in the processing chamber; and a procedure for supplying a second reactive gas having a reducing property to the substrate in the processing chamber; A step of forming a second film containing the metal element on the first film by performing a cycle including a predetermined number of times,
By performing the above, there is provided a program for causing a computer to execute a procedure for forming a film containing the metal element formed by stacking the first film and the second film on the substrate.

  According to the present invention, when a film containing a metal element is formed on a substrate, it is possible to reduce the influence of the film formation base.

It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by embodiment of this invention, and is a figure which shows a processing furnace part with a longitudinal cross-sectional view. It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus used suitably by embodiment of this invention, and is a figure which shows a processing furnace part with the sectional view on the AA line of FIG. It is a schematic block diagram of the controller of the substrate processing apparatus used suitably by embodiment of this invention, and is a figure which shows the control system of a controller with a block diagram. It is a figure which shows the film-forming flow in the film-forming sequence of one Embodiment of this invention. (A) is a figure which shows the timing of the gas supply in the film-forming sequence of one Embodiment of this invention, (b) is a figure which shows the timing of the gas supply in the film-forming sequence of other embodiment of this invention. . (A) (b) is a figure which shows the timing of the gas supply in the film-forming sequence of other embodiment of this invention, respectively. (A)-(c) is a figure which shows the timing of the gas supply in the film-forming sequence of other embodiment of this invention, respectively. (A) (b) is a figure which shows the timing of the gas supply in the film-forming sequence of other embodiment of this invention, respectively.

<One Embodiment of the Present Invention>
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

(1) Configuration of Substrate Processing Apparatus As shown in FIG. 1, the processing furnace 202 has a heater 207 as heating means (heating mechanism). The heater 207 has a cylindrical shape and is vertically installed by being supported by a heater base (not shown) as a holding plate. As will be described later, the heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) gas with heat.

Inside the heater 207, a reaction tube 203 constituting a reaction vessel (processing vessel) concentrically with the heater 207 is disposed. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO ₂ ) or silicon carbide (SiC), and is formed in a cylindrical shape with the upper end closed and the lower end opened. A processing chamber 201 is formed in a cylindrical hollow portion of the reaction tube 203, and is configured so that wafers 200 as substrates can be accommodated in a state of being aligned in multiple stages in a horizontal posture and in a vertical direction by a boat 217 described later.

  In the processing chamber 201, nozzles 249 a and 249 b are provided so as to penetrate the lower part of the reaction tube 203. Gas supply pipes 232a and 232b are connected to the nozzles 249a and 249b, respectively. A gas supply pipe 232c is connected to the gas supply pipe 232a. A gas supply pipe 232f is connected to the gas supply pipe 232b. As described above, the reaction tube 203 is provided with the two nozzles 249a and 249b and the four gas supply tubes 232a to 232c and 232f. It is comprised so that gas can be supplied.

  However, the processing furnace 202 according to the present embodiment is not limited to the above-described form. For example, a metal manifold that supports the reaction tube 203 may be provided below the reaction tube 203, and each nozzle may be provided so as to penetrate the side wall of the manifold. In this case, an exhaust pipe 231 described later may be further provided in the manifold. Even in this case, the exhaust pipe 231 may be provided below the reaction tube 203 instead of the manifold. As described above, the furnace port portion of the processing furnace 202 may be made of metal, and a nozzle or the like may be attached to the metal furnace port portion.

  In the gas supply pipes 232a to 232c and 232f, mass flow controllers (MFC) 241a to 241c and 241f as flow rate controllers (flow rate control units) and valves 243a to 243c and 243f as opening / closing valves are sequentially provided from the upstream direction. Is provided. Gas supply pipes 232d and 232e for supplying an inert gas are connected to the downstream sides of the valves 243a and 243b of the gas supply pipes 232a and 232b, respectively. The gas supply pipes 232d and 232e are provided with MFCs 241d and 241e as flow rate controllers (flow rate control units) and valves 243d and 243e as opening / closing valves, respectively, in order from the upstream direction.

  The nozzles 249a and 249b described above are connected to the distal ends of the gas supply pipes 232a and 232b, respectively. As shown in FIG. 2, the nozzles 249 a and 249 b are arranged in an annular space between the inner wall of the reaction tube 203 and the wafer 200, above the lower portion of the inner wall of the reaction tube 203 and above the loading direction of the wafer 200. It is provided to stand up towards each. That is, the nozzles 249a and 249b are respectively provided along the wafer arrangement area in the area horizontally surrounding the wafer arrangement area on the side of the wafer arrangement area where the wafers 200 are arranged. The nozzles 249a and 249b are each configured as an L-shaped long nozzle, and each horizontal portion thereof is provided so as to penetrate the lower side wall of the reaction tube 203, and each vertical portion thereof is at least arranged in a wafer array. It is provided so as to rise from one end side of the region toward the other end side. Gas supply holes 250a and 250b for supplying gas are provided on the side surfaces of the nozzles 249a and 249b, respectively. The gas supply holes 250 a and 250 b are opened so as to face the center of the reaction tube 203, and gas can be supplied toward the wafer 200. A plurality of gas supply holes 250a and 250b are provided from the lower part to the upper part of the reaction tube 203, each having the same opening area, and further provided at the same opening pitch.

  As described above, in the present embodiment, an annular vertically long space defined by the inner wall of the reaction tube 203 and the ends (peripheries) of the stacked wafers 200, that is, a cylindrical shape. Gas is conveyed via nozzles 249a and 249b arranged in the space. Then, gas is first ejected into the reaction tube 203 from the gas supply holes 250a and 250b opened in the nozzles 249a and 249b, respectively, in the vicinity of the wafer 200. The main flow of gas in the reaction tube 203 is a direction parallel to the surface of the wafer 200, that is, a horizontal direction. With such a configuration, gas can be supplied uniformly to each wafer 200, and the film thickness of the thin film formed on each wafer 200 can be made uniform. The gas flowing on the surface of the wafer 200, that is, the residual gas after the reaction, flows toward the exhaust port, that is, the direction of the exhaust pipe 231 described later. However, the direction of the remaining gas flow is appropriately specified depending on the position of the exhaust port, and is not limited to the vertical direction.

  From the gas supply pipe 232a, for example, tungsten (W) as a predetermined element and a halogen element as a first element gas which is a fluorine (F) -free (F-free) inorganic gas containing a metal element are used. A chlorotungsten-based source gas containing chlorine (Cl) is supplied into the processing chamber 201 through the MFC 241a, the valve 243a, and the nozzle 249a.

A chlorotungsten-based source gas is a gas obtained by vaporizing a chlorotungsten-based source in a gaseous state, for example, a chlorotungsten-based source that is in a solid state or a liquid state at normal temperature and pressure, or in a gaseous state at normal temperature and normal pressure. Some chlorotungsten-based raw materials. The chlorotungsten-based material is a tungsten-based material having a chloro group as a halogen group, and is a material containing at least W and Cl. It can be said that the chlorotungsten-based raw material is a kind of halide. When the term “raw material” is used in the present specification, it means “solid raw material in a solid state”, “liquid raw material in a liquid state”, and “raw material gas in a gaseous state”. May mean all of them. Therefore, when the term “chlorotungsten-based raw material” is used in the present specification, when it means “a chlorotungsten-based raw material in a solid state”, when it means “a chlorotungsten-based raw material in a liquid state”, It may mean “a chlorotungsten-based source gas in a gaseous state” or all of them. As the chlorotungsten-based source gas, an inorganic gas containing W and not containing fluorine (F), that is, a gas containing W and not containing F and carbon (C) is preferably used. For example, hexachlorotungsten (WCl ₆ ) can be preferably used. When using a solid material that is in a solid state at normal temperature and pressure, such as WCl ₆ , for example, a liquefied material that is liquefied by dissolving the solid material in a solvent is vaporized by a vaporization system such as a vaporizer or bubbler. And chlorotungsten-based source gas (WCl ₆ gas).

From the gas supply pipe 232b, for example, diborane (B ₂ H ₆ , abbreviated as DB) gas, which is a hydrogen-containing gas, is supplied as an MFC 241b, a valve 243b, as a first reactive gas and a second reactive gas having reducibility. It is supplied into the processing chamber 201 through the nozzle 249b. The B ₂ H ₆ gas is used as a first reaction gas in a first W film formation step described later, and is used as a second reaction gas in a second W film formation step described later. That is, in this embodiment, B ₂ H ₆ gas that is the same gas, that is, a gas having the same chemical structure is used as the first reaction gas and the second reaction gas.

  However, this embodiment is not limited to this aspect. For example, different gases, that is, gases having different chemical structures may be used as the first reaction gas and the second reaction gas. In this case, in the first W film formation process, for example, the first reaction gas is supplied from the gas supply pipe 232b, and in the second W film formation process, for example, the second reaction gas is supplied from the gas supply pipe 232f. . The gas supplied from the gas supply pipe 232f is supplied into the processing chamber 201 through the MFC 241f, the valve 243f, the gas supply pipe 232b, and the nozzle 249b.

  From the gas supply pipe 232c, as a second source gas containing a metal element and fluorine (F), for example, a fluorotungsten-type source gas containing tungsten (W) as a predetermined element and fluorine (F) as a halogen element Is supplied into the processing chamber 201 through the MFC 241c, the valve 243c, the gas supply pipe 232a, and the nozzle 249a.

The fluorotungsten-type raw material gas is a gaseous fluorotungsten-type raw material, for example, a gas obtained by vaporizing a fluorotungsten-type raw material that is in a liquid state under normal temperature and normal pressure, or a fluorotungsten that is in a gaseous state under normal temperature and normal pressure It is a system raw material. The fluorotungsten-based material is a tungsten-based material having a fluoro group as a halogen group, and is a material containing at least W and F. It can be said that the fluorotungsten-based raw material is a kind of halide. In the present specification, when the term “fluorotungsten-based material” is used, it means “a fluorotungsten-based material in a liquid state”, “a fluorotungsten-based material gas in a gas state”, or May mean both. As the fluorotungsten-based source gas, it is preferable to use an inorganic gas containing W and F, that is, a gas containing W and F and not containing C. For example, hexafluorotungsten (WF ₆ ) is preferably used. it can. When using the gas material in a gaseous state at normal temperature and pressure as WF _6, without vaporized by the vaporizer and bubbler like vaporization system of the WF _6, it is provided as fluoro tungsten-based gas (WF ₆ gas) Can do. On the other hand, when using a fluorotungsten-based material that is in a liquid state at normal temperature and pressure, the fluorotungsten-based material in a liquid state is vaporized by a vaporization system such as a vaporizer or bubbler and supplied as a fluorotungsten-based material gas. It will be.

From the gas supply pipes 232d and 232e, for example, nitrogen (N ₂ ) gas is used as an inert gas via the MFCs 241d and 241e, valves 243d and 243e, gas supply pipes 232a and 232b, and nozzles 249a and 249b, respectively. Supplied into 201.

  When each of the gases as described above is allowed to flow from each gas supply pipe, the first source gas, which is an inorganic gas containing a metal element and not containing F, is mainly supplied from the gas supply pipe 232a, the MFC 241a, and the valve 243a. A first source gas supply system, that is, a chlorotungsten-type source gas supply system is configured. The nozzle 249a may be included in the chlorotungsten-based source gas supply system. The first source gas supply system can also be referred to as a first source gas supply system, and the chlorotungsten source gas supply system can also be referred to as a chlorotungsten source supply system.

In addition, the first reaction gas supply system for supplying the first reactive gas having reducibility and the second reactive gas for supplying the reducible gas mainly by the gas supply pipe 232b, the MFC 241b, and the valve 243b. A two-reaction gas supply system is configured. The first reactive gas supply system and the second reactive gas supply system are each configured as a reducing gas supply system (hydrogen-containing gas supply system). The nozzle 249b may be included in each of the first reactive gas supply system and the second reactive gas supply system. In the present embodiment, since the same reaction gas B ₂ H ₆ gas is used as the first reaction gas and the second reaction gas, the first reaction gas supply system and the second reaction gas supply system are used. The same gas supply system is used.

  However, this embodiment is not limited to this aspect. As described above, different gases can be used as the first reaction gas and the second reaction gas. In this case, the first reaction gas supply system and the second reaction gas supply system are configured by different gas supply systems. For example, the first reaction gas supply system is mainly configured by the gas supply pipe 232b, the MFC 241b, and the valve 243b. Further, for example, a second reaction gas supply system is mainly configured by the gas supply pipe 232f, the MFC 241f, and the valve 243f. Also in this case, the nozzle 249b may be included in the first reaction gas supply system and the second reaction gas supply system, respectively. Further, the downstream side of the nozzle 249b and the gas supply pipe 232b connected to the gas supply pipe 232f may be included in the second reaction gas supply system.

  The gas supply pipe 232c, the MFC 241c, and the valve 243c mainly constitute a second source gas supply system that supplies a second source gas containing a metal element and F, that is, a fluorotungsten-type source gas supply system. . The nozzle 249a may be included in the fluorotungsten-based source gas supply system on the downstream side of the gas supply pipe 232a connected to the gas supply pipe 232c. The second source gas supply system can also be referred to as a second source gas supply system, and the fluorotungsten source gas supply system can also be referred to as a fluorotungsten source supply system.

  Further, an inert gas supply system is mainly configured by the gas supply pipes 232d and 232e, the MFCs 241d and 241e, and the valves 243d and 243e. The nozzles 249a and 249b may be included in the inert gas supply system on the downstream side of the gas supply pipes 232a and 232b connected to the gas supply pipes 232d and 232e. The inert gas supply system also functions as a purge gas supply system.

  Note that the first source gas and the second source gas may be simply referred to as source gas, and in this case, the source gas supply system is configured by the first source gas supply system and the second source gas supply system. . The source gas supply system can also be referred to as a source supply system. In addition, the first reaction gas and the second gas gas may be simply referred to as a reaction gas. In this case, the reaction gas supply system is configured by the first reaction gas supply system and the second reaction gas supply system. The reaction gas supply system can also be referred to as a reducing gas supply system (hydrogen-containing gas supply system).

  The reaction tube 203 is provided with an exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201. The exhaust pipe 231 is connected 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 adjustment unit). A vacuum pump 246 as a vacuum exhaust device is connected. The APC valve 244 can perform vacuum evacuation and vacuum evacuation stop in the processing chamber 201 by opening and closing the valve with the vacuum pump 246 activated, and further, with the vacuum pump 246 activated, The valve is configured such that the pressure in the processing chamber 201 can be adjusted by adjusting the valve opening based on the pressure information detected by the pressure sensor 245. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. The vacuum pump 246 may be included in the exhaust system.

  Below the reaction tube 203, a seal cap 219 is provided as a furnace opening lid capable of airtightly closing the lower end opening of the reaction tube 203. The seal cap 219 is configured to contact the lower end of the reaction tube 203 from the lower side in the vertical direction. The seal cap 219 is made of a metal such as stainless steel (SUS) and is formed in a disk shape. An O-ring 220 is provided on the upper surface of the seal cap 219 as a seal member that contacts the lower end of the reaction tube 203. On the opposite side of the seal cap 219 from the processing chamber 201, a rotation mechanism 267 for rotating a boat 217 described later is installed. A rotation shaft 255 of the rotation mechanism 267 passes through the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be lifted and lowered in the vertical direction by a boat elevator 115 as a lifting mechanism vertically installed outside the reaction tube 203. The boat elevator 115 is configured so that the boat 217 can be carried in and out of the processing chamber 201 by moving the seal cap 219 up and down. The boat elevator 115 is configured as a transfer device (transfer mechanism) that transfers the boat 217, that is, the wafers 200 into and out of the processing chamber 201.

  The boat 217 as the substrate support is configured to support a plurality of, for example, 100 to 200, wafers 200 in a horizontal posture and in a multi-stage by aligning them in the vertical direction with their centers aligned. Are arranged so as to be spaced apart. The boat 217 is made of a heat-resistant material such as quartz or SiC. Under the boat 217, heat insulating plates 218 made of a heat-resistant material such as quartz or SiC are supported in multiple stages in a horizontal posture so that heat from the heater 207 is not easily transmitted to the seal cap 219 side. Yes. However, the present embodiment is not limited to such a form. For example, instead of providing the heat insulating plate 218 in the lower portion of the boat 217, a heat insulating cylinder configured as a cylindrical member made of a heat resistant material such as quartz or SiC may be provided.

  A temperature sensor 263 as a temperature detector is installed in the reaction tube 203. By adjusting the power supply to the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature in the processing chamber 201 has a desired temperature distribution. The temperature sensor 263 is configured in an L shape similarly to the nozzles 249a and 249b, and is provided along the inner wall of the reaction tube 203.

  As shown in FIG. 3, the controller 121, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. Has been. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to exchange data with the CPU 121a via the internal bus 121e. For example, an input / output device 122 configured as a touch panel or the like is connected to the controller 121.

  The storage device 121c is configured by, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 121c, a control program that controls the operation of the substrate processing apparatus, a process recipe that describes the procedure and conditions of the substrate processing described later, and the like are stored in a readable manner. The process recipe is a combination of the controller 121 that allows the controller 121 to execute each procedure in the substrate processing process described later and obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, the control program, and the like are collectively referred to simply as a program. When the term “program” is used in this specification, it may include only a process recipe alone, only a control program alone, or both. The RAM 121b is configured as a memory area (work area) in which programs, data, and the like read by the CPU 121a are temporarily stored.

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

  The CPU 121a is configured to read out and execute a control program from the storage device 121c, and to read out a process recipe from the storage device 121c in response to an operation command input from the input / output device 122 or the like. The CPU 121a adjusts the flow rate of various gases by the MFCs 241a to 241e, the opening / closing operation of the valves 243a to 243e, the opening / closing operation of the APC valve 244, and the pressure by the APC valve 244 based on the pressure sensor 245 so as to match the contents of the read process recipe. Adjusting operation, starting and stopping of the vacuum pump 246, temperature adjusting operation of the heater 207 based on the temperature sensor 263, rotation and rotation speed adjusting operation of the boat 217 by the rotating mechanism 267, lifting and lowering operation of the boat 217 by the boat elevator 115, and the like are controlled. It is configured as follows.

  The controller 121 is not limited to being configured as a dedicated computer, and may be configured as a general-purpose computer. For example, an external storage device storing the above-described program (for example, magnetic tape, magnetic disk such as a flexible disk or hard disk, optical disk such as CD or DVD, magneto-optical disk such as MO, semiconductor memory such as USB memory or memory card) 123 is prepared, and the controller 121 according to the present embodiment can be configured by installing a program in a general-purpose computer using the external storage device 123. However, the means for supplying the program to the computer is not limited to supplying the program via the external storage device 123. For example, the program may be supplied without using the external storage device 123 by using communication means such as the Internet or a dedicated line. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these are collectively referred to simply as a recording medium. When the term “recording medium” is used in this specification, it may include only the storage device 121c alone, may include only the external storage device 123 alone, or may include both.

(2) Substrate Processing Step Next, a sequence example in which a thin film is formed on a substrate will be described as one step of a semiconductor device (device) manufacturing process using the above-described processing furnace of the substrate processing apparatus. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

In the film forming sequence of this embodiment,
A step of supplying a first source gas which is an inorganic gas containing a metal element and containing no fluorine to the substrate; and a step of supplying a first reactive gas having reducibility to the substrate. Forming a first film containing the metal element on the substrate by performing a cycle including the predetermined number of times;
A cycle including a step of supplying a second source gas containing the metal element and fluorine to the substrate and a step of supplying a second reactive gas having a reducing property to the substrate is performed a predetermined number of times. And forming a second film containing the metal element on the first film;
By performing the above, a film containing the metal element formed by stacking the first film and the second film is formed on the substrate.

  Note that “performing a predetermined number of cycles including a step of supplying a source gas and a step of supplying a reactive gas” alternately includes a step of supplying a source gas and a step of supplying a reactive gas, Or, when the cycle performed simultaneously is one cycle, this means that this cycle is performed once or a plurality of times. That is, this cycle is performed once or more. In other words, a cycle in which the process of supplying the source gas and the process of supplying the reaction gas are performed alternately or simultaneously is performed once or repeated a plurality of times. However, this cycle is preferably repeated a plurality of times.

  In addition, the “film containing a metal element” means a film made of a conductive substance containing a metal element, which includes a film made of a metal element alone, that is, a metal element. A membrane as a component is included. In addition, the “film containing a metal element” includes a conductive metal nitride film, a conductive metal oxide film, a conductive metal oxynitride film, a conductive metal composite, in addition to a film composed of a single metal element. A film, a conductive metal alloy film, a conductive metal silicide film, a conductive metal carbide film (metal carbide film), and the like are included. These may be collectively referred to simply as a metal film (metal film).

  Hereinafter, the film forming sequence of the present embodiment will be described with reference to FIGS. 4 and 5A.

In the film forming sequence shown in FIG. 4 and FIG.
A step of supplying WCl ₆ gas as a first source gas, which is an inorganic gas containing W and not containing F, to wafer 200, and B ₂ as a first reactive gas having reducibility to wafer 200 Forming a first film containing W (first W film) on the wafer 200 by performing a cycle including the step of supplying H ₆ gas a predetermined number of times,
A step of supplying WF ₆ gas as a second source gas containing W and F to the wafer 200, and a step of supplying B ₂ H ₆ gas as a _second reactive gas having reducibility to the wafer 200; Forming a second film containing W (second W film) on the first film by performing a cycle including a predetermined number of times,
By performing the above, a film (W film) containing W formed by laminating the first film (first W film) and the second film (second W film) is formed on the wafer 200. .

  4 and 5A, the first W film is formed by alternately performing the process of supplying the first source gas and the process of supplying the first reaction gas a predetermined number of times (m times). An example is shown in which the second W film is formed by alternately performing the step of supplying the second source gas and the step of supplying the second reactive gas a predetermined number of times (n times). .

  Note that each of the first W film and the second W film is a film composed of W alone, that is, a film containing W as a main component. The W film formed by laminating the first W film and the second W film is also a film composed of W alone, that is, a film containing W as a main component. In addition, a first W layer and a second W layer, which will be described later, are also layers each composed of W alone, that is, a layer mainly composed of W. In the present specification, each portion expressed as “a film (or layer) composed of W alone” can be read as “a film (or layer) containing W as a main component”. The same applies to other embodiments and modifications described later.

  In addition, when the term “wafer” is used in this specification, it means “wafer itself” or “a laminate (aggregate) of a wafer and a predetermined layer or film formed on the surface thereof”. ", That is, a predetermined layer or film formed on the surface may be referred to as a wafer. In addition, when the term “wafer surface” is used in this specification, it means “the surface of the wafer itself (exposed surface)” or “the surface of a predetermined layer or film formed on the wafer”. That is, it may mean “the outermost surface of the wafer as a laminated body”.

  Therefore, in the present specification, the phrase “supplying a predetermined gas to the wafer” means “supplying a predetermined gas directly to the surface (exposed surface) of the wafer itself”. , It may mean that “a predetermined gas is supplied to a layer, a film, or the like formed on the wafer, that is, to the outermost surface of the wafer as a laminated body”. Further, in this specification, when “describe a predetermined layer (or film) on the wafer” is described, “determine a predetermined layer (or film) directly on the surface (exposed surface) of the wafer itself”. This means that a predetermined layer (or film) is formed on a layer or film formed on the wafer, that is, on the outermost surface of the wafer as a laminate. There is a case.

  In this specification, the term “substrate” is used in the same manner as the term “wafer”. In that case, in the above description, “wafer” may be replaced with “substrate”.

(Wafer charge and boat load)
When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), as shown in FIG. 1, the boat 217 that supports the plurality of wafers 200 is lifted by the boat elevator 115 and loaded into the processing chamber 201 (boat). Loaded). In this state, the seal cap 219 seals the lower end of the reaction tube 203 via the O-ring 220.

  On the surface of the wafer 200, for example, a silicon film (Si film), a silicon oxide film (SiO film), a silicon nitride film (SiN film), a silicon carbide film (SiC film), a silicon carbonitride film (SiCN film), silicon Si-containing films such as oxynitride films (SiON films), silicon oxycarbide films (SiOC films), silicon oxycarbonitride films (SiOCN films), aluminum oxide films (AlO films), hafnium oxide films (HfO films), zirconium Metal oxide films such as oxide films (ZrO films) and titanium oxide films (TiO films), that is, high dielectric constant insulating films (High-k films), metal nitride films such as titanium nitride films (TiN films), etc. Pre-formed. Further, for example, on the surface of the wafer 200, a laminated film in which these films are laminated, for example, a laminated film in which a TiN film is laminated on an AlO film, an HfO film, or a ZrO film (TiN / AlO, TiN / HfO, TiN). / ZrO) may be formed in advance. These films become at least a part of the base film when the first W film is formed in the first W film forming step described later. It can also be said that these films become at least a part of a base film in forming a W film in which a first W film and a second W film are laminated. The oxide film (or oxynitride film, oxycarbide film, oxycarbonitride film) here is an oxide film intentionally formed by performing a predetermined process such as a thermal oxidation process or a plasma oxidation process. In addition, a natural oxide film formed naturally by exposure to the atmosphere during transportation or the like is included.

(Pressure adjustment and temperature adjustment)
Vacuum is exhausted by the vacuum pump 246 so that the pressure in the processing chamber 201, that is, the pressure in the space where the wafer 200 exists becomes a desired pressure (degree of vacuum). 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 (pressure adjustment). The vacuum pump 246 maintains a state in which it is always operated until at least the processing on the wafer 200 is completed. Further, the wafer 200 in the processing chamber 201 is heated by the heater 207 so as to reach a desired temperature. At this time, the power supply to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the inside of the processing chamber 201 has a desired temperature distribution (temperature adjustment). Heating of the processing chamber 201 by the heater 207 is continuously performed at least until the processing on the wafer 200 is completed. Subsequently, rotation of the boat 217 and the wafers 200 by the rotation mechanism 267 is started. The rotation of the boat 217 and the wafer 200 by the rotation mechanism 267 is continuously performed at least until the processing on the wafer 200 is completed.

(First W film forming step)
Thereafter, the next two steps, that is, steps 1a and 2a are sequentially executed.

[Step 1a]
(WCl ₆ gas supply)
The valve 243a is opened, and WCl ₆ gas is allowed to flow through the gas supply pipe 232a. The flow rate of the WCl ₆ gas is adjusted by the MFC 241a, supplied into the processing chamber 201 from the gas supply hole 250a, and exhausted from the exhaust pipe 231. At this time, WCl ₆ gas is supplied to the wafer 200. At the same time, the valve 243d is opened and an inert gas such as N ₂ gas is allowed to flow into the gas supply pipe 232d. The flow rate of the N ₂ gas is adjusted by the MFC 241d, supplied to the processing chamber 201 together with the WCl ₆ gas, and exhausted from the exhaust pipe 231.

At this time, in order to prevent the WCl ₆ gas from entering the nozzle 249b, the valve 243e is opened, and N ₂ gas is allowed to flow into the gas supply pipe 232e. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipe 232b and the nozzle 249b, and is exhausted from the exhaust pipe 231.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 1 to 5000 Pa, preferably 10 to 1000 Pa, more preferably 50 to 500 Pa. The supply flow rate of the WCl ₆ gas controlled by the MFC 241a is, for example, a flow rate in the range of 1 to 2000 sccm. The supply flow rate of the N ₂ gas controlled by the MFCs 241d and 241e is, for example, a flow rate in the range of 100 to 10000 sccm. The time for supplying the WCl ₆ gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, 1 to 120 seconds, preferably 1 to 60 seconds. At this time, the temperature of the heater 207 is set to such a temperature that the temperature of the wafer 200 is, for example, 150 to 700 ° C., preferably 180 to 600 ° C., more preferably 200 to 400 ° C.

When the temperature of the wafer 200 is less than 150 ° C., WCl ₆ is difficult to be chemically adsorbed on the wafer 200, and a practical film formation rate may not be obtained. This can be solved by setting the temperature of the wafer 200 to 150 ° C. or higher. By setting the temperature of the wafer 200 to 180 ° C. or higher, further 200 ° C. or higher, WCl ₆ can be more sufficiently adsorbed on the wafer 200, and a more sufficient film formation rate can be obtained.

  When the temperature of the wafer 200 exceeds 700 ° C., the CVD reaction becomes strong (the gas phase reaction becomes dominant), so that the film thickness uniformity tends to be deteriorated and the control becomes difficult. By setting the temperature of the wafer 200 to 700 ° C. or lower, it is possible to suppress the deterioration of the film thickness uniformity and to control it. In particular, when the temperature of the wafer 200 is set to 600 ° C. or lower, and further to 400 ° C. or lower, the surface reaction becomes dominant, the film thickness uniformity is easily ensured, and the control becomes easy.

  Therefore, the temperature of the wafer 200 is set to 150 to 700 ° C., preferably 180 to 600 ° C., more preferably 200 to 400 ° C.

By supplying WCl ₆ gas to the wafer 200 under the above-described conditions, a W-containing layer containing Cl having a thickness of, for example, less than one atomic layer to several atomic layers is formed on the base film on the surface of the wafer 200. Is done. The W-containing layer containing Cl may be an adsorption layer of WCl ₆ gas, a W layer containing Cl, or both of them.

  The W layer containing Cl is a generic name including a continuous layer made of W and containing Cl, a discontinuous layer, and a W thin film containing Cl formed by overlapping these layers. A continuous layer composed of W and containing Cl may be referred to as a W thin film containing Cl. W constituting the W layer containing Cl includes not only those that are not completely disconnected from Cl but also those that are completely disconnected from Cl.

Adsorption layers of WCl ₆ gas, other continuous adsorption layer of gas molecules WCl ₆ gas, also includes a discontinuous adsorption layer. That is, the adsorption layer of WCl ₆ gas includes an adsorption layer having a thickness of less than one molecular layer composed of WCl ₆ molecules or less than one molecular layer. WCl ₆ molecules constituting the adsorption layer of WCl ₆ gas, including those bonds between W and Cl is partially broken. That is, the WCl ₆ gas adsorption layer may be a WCl ₆ gas physical adsorption layer, a WCl ₆ gas chemical adsorption layer, or both of them.

  In this specification, a layer having a thickness of less than one atomic layer means an atomic layer formed discontinuously, and a layer having a thickness of one atomic layer is formed continuously. It means an atomic layer. A layer having a thickness of less than one molecular layer means a molecular layer formed discontinuously, and a layer having a thickness of one molecular layer means a molecular layer formed continuously. ing.

Under the condition that the WCl ₆ gas is self-decomposed (thermally decomposed), that is, under the condition that the thermal decomposition reaction of the WCl ₆ gas occurs, the W layer containing Cl is formed by depositing W on the wafer 200. Conditions WCl ₆ gas is not autolyzed (pyrolyzed), i.e., in a condition in which a pyrolysis reaction of WCl ₆ gas does not occur, the adsorption layer of WCl ₆ gas by WCl ₆ gas on the wafer 200 is adsorbed is formed Is done. It is preferable to form a W layer containing Cl rather than forming a WCl ₆ gas adsorption layer on the wafer 200 because the film formation rate can be increased.

  When the thickness of the W-containing layer containing Cl formed on the wafer 200 exceeds several atomic layers, the modification effect in Step 2a described later does not reach the entire W-containing layer containing Cl. Further, the minimum value of the thickness of the W-containing layer containing Cl that can be formed on the wafer 200 is less than one atomic layer. Therefore, the thickness of the W-containing layer containing Cl is preferably less than one atomic layer to several atomic layers. Further, by setting the thickness of the W-containing layer containing Cl to 1 atomic layer or less, that is, 1 atomic layer or less than 1 atomic layer, the action of the reforming reaction in Step 2a described later can be relatively enhanced. The time required for the reforming reaction in step 2a can be shortened. The time required for forming the W-containing layer containing Cl in Step 1a can also be shortened. As a result, the processing time per cycle can be shortened, and the total processing time can be shortened. That is, the film forming rate can be increased. In addition, by controlling the thickness of the W-containing layer containing Cl to be 1 atomic layer or less, the controllability of film thickness uniformity can be improved.

(Residual gas removal)
After the W-containing layer containing Cl is formed, the valve 243a is closed and the supply of WCl ₆ gas is stopped. At this time, the APC valve 244 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the WCl ₆ gas that has remained in the processing chamber 201 and has contributed to the formation of a W-containing layer containing Cl. Are removed from the processing chamber 201. At this time, the valves 243d and 243e are kept open, and the supply of N ₂ gas as an inert gas into the processing chamber 201 is maintained. The N ₂ gas acts as a purge gas, thereby enhancing the effect of removing the WCl ₆ gas remaining in the processing chamber 201 or contributing to the formation of the W-containing layer containing Cl from the processing chamber 201. it can.

At this time, the gas remaining in the processing chamber 201 may not be completely removed, and the inside of the processing chamber 201 may not be completely purged. If the amount of gas remaining in the processing chamber 201 is very small, no adverse effects will occur in the subsequent step 2a. At this time, the flow rate of the N ₂ gas supplied into the processing chamber 201 does not need to be a large flow rate. For example, by supplying an amount similar to the volume of the reaction tube 203 (processing chamber 201), in step 2a Purge can be performed to the extent that no adverse effect occurs. By not completely purging the inside of the processing chamber 201, the purge time can be shortened and the throughput can be improved. In addition, consumption of N ₂ gas can be minimized.

As the first source gas, inorganic chloro such as dichlorotungsten (WCl ₂ ) gas, oxytetrachlorotungsten (WOCl ₅ ) gas, azidopentachlorotungsten (Cl ₅ N ₃ W) gas as well as WCl ₆ gas. A tungsten-based gas may be used.

As the inert gas, a rare gas such as Ar gas, He gas, Ne gas, or Xe gas may be used in addition to N ₂ gas.

[Step 2a]
(B ₂ H ₆ gas supply)
After step 1a is completed and residual gas in the processing chamber 201 is removed, the valve 243b is opened, and B ₂ H ₆ gas is allowed to flow into the gas supply pipe 232b. The flow rate of the B ₂ H ₆ gas is adjusted by the MFC 241b, supplied into the processing chamber 201 from the gas supply hole 250b, and exhausted from the exhaust pipe 231. At this time, B ₂ H ₆ gas activated by heat is supplied to the wafer 200. At the same time, the valve 243e is opened, and N ₂ gas as an inert gas is caused to flow into the gas supply pipe 232e. The flow rate of the N ₂ gas is adjusted by the MFC 241e, is supplied into the processing chamber 201 together with the B ₂ H ₆ gas, and is exhausted from the exhaust pipe 231.

At this time, in order to prevent B ₂ H ₆ gas from entering the nozzle 249a, the valve 243d is opened and N ₂ gas is allowed to flow into the gas supply pipe 232d. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipe 232a and the nozzle 249a, and is exhausted from the exhaust pipe 231.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 1 to 5000 Pa, preferably 10 to 1000 Pa, more preferably 50 to 500 Pa. By setting the pressure in the processing chamber 201 to such a pressure zone, the B ₂ H ₆ gas can be thermally activated by non-plasma. By supplying the B ₂ H ₆ gas after being activated by heat, a soft reaction can be generated, and the later-described modification can be performed softly. The supply flow rate of the B ₂ H ₆ gas controlled by the MFC 241b is, for example, a flow rate in the range of 1 to 2000 sccm. The supply flow rate of the N ₂ gas controlled by the MFCs 241d and 241e is, for example, a flow rate in the range of 100 to 10000 sccm. The time for supplying the heat-activated B ₂ H ₆ gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, 1 to 120 seconds, preferably 1 to 60 seconds. To do. The temperature of the heater 207 at this time is the temperature at which the temperature of the wafer 200 becomes, for example, 150 to 700 ° C., preferably 180 to 600 ° C., more preferably 200 to 400 ° C., as in step 1a. Set to.

By supplying B ₂ H ₆ gas to the wafer 200 under the above-described conditions, the W-containing layer containing Cl formed on the base film of the wafer 200 in step 1a reacts with the B ₂ H ₆ gas. . That is, Cl (chloro group), which is a halogen element (halogen group) contained in the W-containing layer containing Cl, and B ₂ H ₆ gas can be reacted. Thereby, Cl in the W-containing layer containing Cl reacted with B ₂ H ₆ can be separated (pulled out) from the W-containing layer containing Cl. By this reaction, Cl is desorbed from the W-containing layer containing Cl, and the W-containing layer containing Cl is changed (modified) to the first layer (first W layer) containing W. The first W layer is a layer composed of simple W having a thickness of less than one atomic layer to several atomic layers, that is, a layer mainly composed of W.

When the first W layer is formed, Cl contained in the W-containing layer containing Cl and B ₂ H ₆ gas are converted into the W-containing layer containing Cl by the B ₂ H ₆ gas. In the process, a gaseous substance containing at least one of Cl, B, and H is formed and discharged from the processing chamber 201 through the exhaust pipe 231. That is, impurities such as Cl in the W-containing layer containing Cl are separated from the W-containing layer containing Cl by being extracted or desorbed from the W-containing layer containing Cl. As a result, the first W layer is a layer having less impurities such as Cl as compared with the W-containing layer containing Cl.

(Residual gas removal)
After the first W layer is formed, the valve 243b is closed and the supply of B ₂ H ₆ gas is stopped. At this time, the APC valve 244 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and B ₂ H ₆ after contributing to the formation of unreacted or first W layer remaining in the processing chamber 201. Gases and reaction byproducts are removed from the processing chamber 201. At this time, the valves 243d and 243e are kept open, and the supply of N ₂ gas as an inert gas into the processing chamber 201 is maintained. The N ₂ gas acts as a purge gas, thereby removing unreacted B ₂ H ₆ gas and reaction byproducts remaining in the processing chamber 201 or contributing to the formation of the first W layer from the processing chamber 201. Can enhance the effect.

At this time, the gas remaining in the processing chamber 201 may not be completely removed, and the inside of the processing chamber 201 may not be completely purged. If the amount of gas remaining in the processing chamber 201 is very small, no adverse effect will occur in the subsequent step 1a. At this time, the flow rate of the N ₂ gas supplied into the processing chamber 201 does not need to be a large flow rate. For example, by supplying an amount similar to the volume of the reaction tube 203 (processing chamber 201), adverse effects are caused in step 1a. Purging to such an extent that no occurrence occurs can be performed. By not completely purging the inside of the processing chamber 201, the purge time can be shortened and the throughput can be improved. In addition, consumption of N ₂ gas can be minimized.

Examples of the first reaction gas include B ₂ H ₆ gas, inorganic borane-based gas such as triborane (B ₃ H ₈ , abbreviation: TB) gas, monoborane (BH ₃ , abbreviation: MB) gas, and trisilane (Si _3). Inorganic silane gases such as H ₈ , abbreviation: TS) gas, disilane (Si ₂ H ₆ , abbreviation: DS) gas, monosilane (SiH ₄ , abbreviation: MS) gas, hydrogen (H ₂ ) gas, ammonia (NH ₃₎ ) Gas, hydrazine (N ₂ H ₄ ) gas, diazene (N ₂ H ₂ ) gas, or the like can be used. That is, as the first reaction gas, a C-free hydrogen-containing gas, that is, an inorganic hydrogen-containing gas can be used.

As the inert gas, a rare gas such as Ar gas, He gas, Ne gas, or Xe gas may be used in addition to N ₂ gas.

(Performed times)
The above-described steps 1a and 2a are set as one cycle, and this cycle is performed once or more (predetermined number of times), that is, steps 1a and 2a are alternately performed once or more (predetermined number of times), thereby On the ground film, as the first W film, a film composed of W having a predetermined thickness, that is, a W film that is a film containing W as a main component can be formed.

If the thickness of the first W film is less than one atomic layer, that is, if the first W film is discontinuous, in the second W film forming process described later, The second source gas (WF ₆ gas) may be directly supplied. That is, the WF ₆ gas may come into direct contact with the underlying film on the wafer 200 surface. In addition, in the second W film formation step and the heat treatment step described later, the F diffusion suppression effect (barrier effect) by the first W film may be reduced. As a result, the underlying film on the surface of the wafer 200 may be etched by F, or F may diffuse into the underlying film on the surface of the wafer 200. By setting the thickness of the first W film to 1 atomic layer or more, preferably 1 nm or more, more preferably 5 nm or more, WF ₆ gas is not directly supplied to the base film on the surface of the wafer 200, and The effect of suppressing the diffusion of F by the first W film can be increased, and as a result, the influence of F on the underlying film on the surface of the wafer 200 can be suppressed.

Further, if the thickness of the first W film exceeds 15 nm, the total film formation time of the W film formed by laminating the first W film and the second W film becomes long, and the film formation process is performed. Productivity may be reduced. WCl ₆ gas is less reactive than WF ₆ gas, and when the film is formed under the same conditions, the film formation rate is lower when WCl ₆ gas is used than when WF ₆ gas is used. End up. Therefore, if the film formation time using WCl ₆ gas becomes too long as in the case where the thickness of the first W film exceeds 15 nm, the total film formation time is affected. If the thickness of the first W film exceeds 15 nm, the amount of relatively expensive WCl ₆ gas used may increase, and the cost of the film forming process may increase. By setting the thickness of the first W film to 15 nm or less, preferably 10 nm or less, the total film formation time of the W film can be shortened, and the productivity of the film formation process can be improved. . In addition, the usage amount of the WCl ₆ gas can be appropriately suppressed, and the cost of the film forming process can be reduced.

  Therefore, the thickness of the first W film is preferably not less than 1 atomic layer, preferably not less than 1 nm and not more than 15 nm, more preferably not less than 5 nm and not more than 10 nm.

  The above cycle is preferably repeated multiple times. That is, it is preferable that the thickness of the first W layer formed per cycle is made smaller than the desired film thickness, and the above cycle is repeated a plurality of times until the desired film thickness is obtained.

  In the case where the cycle is performed a plurality of times, at least in each step after the second cycle, the portion described as “supplying a predetermined gas to the wafer 200” is “to the layer formed on the wafer 200, That is, it means that a predetermined gas is supplied to the outermost surface of the wafer 200 as a laminated body, and a portion described as “form a predetermined layer on the wafer 200” is “formed on the wafer 200”. It means that a predetermined layer is formed on the applied layer, that is, on the outermost surface of the wafer 200 as a laminate. This point is as described above. This also applies to the second W film forming step and other embodiments described later.

(Second W film forming step)
Thereafter, the next two steps, that is, steps 1b and 2b are sequentially executed.

[Step 1b]
(WF ₆ gas supply)
The valve 243c is opened and WF ₆ gas is allowed to flow into the gas supply pipe 232c. The flow rate of the WF ₆ gas is adjusted by the MFC 241c, supplied to the processing chamber 201 from the gas supply hole 250a via the gas supply pipe 232a, and exhausted from the exhaust pipe 231. At this time, WF ₆ gas is supplied to the wafer 200. At the same time, the valve 243d is opened and an inert gas such as N ₂ gas is allowed to flow into the gas supply pipe 232d. The flow rate of the N ₂ gas is adjusted by the MFC 241d, supplied into the processing chamber 201 together with the WF ₆ gas, and exhausted from the exhaust pipe 231.

At this time, in order to prevent the WF ₆ gas from entering the nozzle 249b, the valve 243e is opened and N ₂ gas is allowed to flow into the gas supply pipe 232e. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipe 232b and the nozzle 249b, and is exhausted from the exhaust pipe 231.

At this time, the APC valve 244 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, 1 to 5000 Pa, preferably 10 to 1000 Pa, more preferably 50 to 500 Pa. The supply flow rate of the WF ₆ gas controlled by the MFC 241c is, for example, a flow rate in the range of 1 to 2000 sccm. The supply flow rate of the N ₂ gas controlled by the MFCs 241d and 241e is, for example, a flow rate in the range of 100 to 10000 sccm. The time for supplying the WF ₆ gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, 1 to 120 seconds, preferably 1 to 60 seconds. At this time, the temperature of the heater 207 is the same as that in the first W film forming step, that is, the temperature of the wafer 200 is, for example, in the range of 150 to 700 ° C., preferably 180 to 600 ° C., more preferably 200 to 400 ° C. Set the temperature so that the temperature is within the range.

When the temperature of the wafer 200 is lower than 150 ° C., WF ₆ is difficult to be chemically adsorbed on the wafer 200, and a practical film formation rate may not be obtained. This can be solved by setting the temperature of the wafer 200 to 150 ° C. or higher. By setting the temperature of the wafer 200 to 180 ° C. or higher, further 200 ° C. or higher, WF ₆ can be more sufficiently adsorbed on the wafer 200, and a more sufficient film formation rate can be obtained.

  When the temperature of the wafer 200 exceeds 700 ° C., the CVD reaction becomes strong (the gas phase reaction becomes dominant), so that the film thickness uniformity tends to be deteriorated and the control becomes difficult. By setting the temperature of the wafer 200 to 700 ° C. or lower, it is possible to suppress the deterioration of the film thickness uniformity and to control it. In particular, when the temperature of the wafer 200 is set to 600 ° C. or lower, and further to 400 ° C. or lower, the surface reaction becomes dominant, the film thickness uniformity is easily ensured, and the control becomes easy.

  Therefore, the temperature of the wafer 200 is set to 150 to 700 ° C., preferably 180 to 600 ° C., more preferably 200 to 400 ° C.

By supplying WF ₆ gas to the wafer 200 under the above-described conditions, a W-containing layer containing F having a thickness of, for example, less than one atomic layer to several atomic layers is formed on the first W film. The The W-containing layer containing F may be an adsorption layer of WF ₆ gas, a W layer containing F, or both of them.

  The W layer containing F is a generic name including a continuous layer made of W and containing F, a discontinuous layer, and a W thin film containing F formed by overlapping these layers. A continuous layer composed of W and containing F may be referred to as a W thin film containing F. W constituting the W layer containing F includes not only completely broken bond with F but also completely broken bond with F.

Adsorption layers of the WF ₆ gas, other continuous adsorption layer of gas molecules WF ₆ gas, also includes a discontinuous adsorption layer. That is, the adsorption layer of WF ₆ gas includes an adsorption layer having a thickness of less than one molecular layer or less than one molecular layer composed of WF ₆ molecules. WF ₆ molecules constituting the adsorption layer of the WF ₆ gas, including those bonds between W and F are partially broken. That is, the WF ₆ gas adsorption layer may be a WF ₆ gas physical adsorption layer, a WF ₆ gas chemisorption layer, or both of them.

Under the condition that the WF ₆ gas is self-decomposed (pyrolysis), that is, under the condition that the thermal decomposition reaction of the WF ₆ gas occurs, a W layer containing F is formed by depositing W on the first W film. The Conditions WF ₆ gas is not autolyzed (pyrolyzed), i.e., in a condition in which a pyrolysis reaction of WF ₆ gas does not occur, the adsorption of the WF ₆ gas by WF ₆ gas is adsorbed on the first W film A layer is formed. It is preferable to form a W layer containing F rather than forming an adsorption layer of WF ₆ gas on the first W film because the film formation rate can be increased.

  When the thickness of the W-containing layer containing F formed on the first W film exceeds several atomic layers, the modification effect in Step 2b described later does not reach the entire W-containing layer containing F. The minimum value of the thickness of the W-containing layer containing F that can be formed on the first W film is less than one atomic layer. Therefore, the thickness of the W-containing layer containing F is preferably set to be less than one atomic layer to several atomic layers. Further, by setting the thickness of the W-containing layer containing F to 1 atomic layer or less, that is, 1 atomic layer or less than 1 atomic layer, the effect of the reforming reaction in step 2b described later can be relatively enhanced. This can shorten the time required for the reforming reaction in step 2b. The time required for forming the W-containing layer containing F in Step 1b can also be shortened. As a result, the processing time per cycle can be shortened, and the total processing time can be shortened. That is, the film forming rate can be increased. Moreover, it becomes possible to improve the controllability of film thickness uniformity by setting the thickness of the W-containing layer containing F to 1 atomic layer or less.

(Residual gas removal)
After the W-containing layer containing F is formed, the valve 243c is closed and the supply of WF ₆ gas is stopped. At this time, the APC valve 244 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the WF ₆ gas after contributing to the formation of the unreacted or W-containing layer containing F remaining in the processing chamber 201 Are removed from the processing chamber 201. At this time, the valves 243d and 243e are kept open, and the supply of N ₂ gas as an inert gas into the processing chamber 201 is maintained. The N ₂ gas acts as a purge gas, thereby enhancing the effect of removing the unreacted WF ₆ gas remaining in the processing chamber 201 or forming a W-containing layer containing F from the processing chamber 201. it can.

At this time, the gas remaining in the processing chamber 201 may not be completely removed, and the inside of the processing chamber 201 may not be completely purged. If the amount of gas remaining in the processing chamber 201 is very small, no adverse effect will occur in the subsequent step 2b. At this time, the flow rate of the N ₂ gas supplied into the processing chamber 201 does not need to be a large flow rate. For example, by supplying an amount similar to the volume of the reaction tube 203 (processing chamber 201), in step 2b Purge can be performed to the extent that no adverse effect occurs. By not completely purging the inside of the processing chamber 201, the purge time can be shortened and the throughput can be improved. In addition, consumption of N ₂ gas can be minimized.

As the second source gas, in addition to the WF ₆ gas, another inorganic fluorotungsten gas may be used.

As the inert gas, a rare gas such as Ar gas, He gas, Ne gas, or Xe gas may be used in addition to N ₂ gas.

[Step 2b]
(B ₂ H ₆ gas supply)
After step 1b is completed and the residual gas in the processing chamber 201 is removed, step 2b of supplying B ₂ H ₆ gas as the second reaction gas to the wafer 200 is performed. Step 2b is performed in the same manner as step 2a described above.

By supplying B ₂ H ₆ gas to the wafer 200 under the same procedure and the same conditions as in Step 2a, the W-containing layer containing F and B ₂ formed on the first W film in Step 1b H ₆ gas reacts. That is, F (fluoro group) which is a halogen element (halogen group) contained in the W-containing layer containing F can be reacted with B ₂ H ₆ gas. Thereby, F in the W-containing layer containing F reacted with B ₂ H ₆ can be separated (pulled out) from the W-containing layer containing F. By this reaction, F is desorbed from the W-containing layer containing F, and the W-containing layer containing F is changed (modified) into a second layer (second W layer) containing W. The second W layer is a layer composed of simple W having a thickness of less than one atomic layer to several atomic layers, that is, a layer mainly composed of W.

When the second W layer is formed, F contained in the W-containing layer containing F and B ₂ H ₆ gas are modified by the reforming reaction of the W-containing layer containing F by B ₂ H ₆ gas. In the process, a gaseous substance containing at least one of F, B, and H is formed and discharged from the processing chamber 201 through the exhaust pipe 231. That is, impurities such as F in the W-containing layer containing F are separated from the W-containing layer containing F by being extracted or desorbed from the W-containing layer containing F. As a result, the second W layer is a layer with less impurities such as F compared to the W-containing layer containing F.

(Residual gas removal)
After the second W layer is formed, the B ₂ H ₆ gas and the reaction by-product remaining in the processing chamber 201 and contributing to the unreacted reaction or the reaction by the same procedure and the same conditions as in Step 2a described above. Objects are removed from the processing chamber 201. At this time, the gas remaining in the processing chamber 201 may not be completely removed, and the inside of the processing chamber 201 may not be completely purged as in step 2a described above.

  As the second reaction gas, the same gas as the first reaction gas, that is, an inorganic hydrogen-containing gas can be used. Moreover, the same gas can also be used as 1st reaction gas and 2nd reaction gas, and different gas can also be used.

As the inert gas, a rare gas such as Ar gas, He gas, Ne gas, or Xe gas may be used in addition to N ₂ gas.

(Performed times)
The above-described steps 1b and 2b are defined as one cycle, and this cycle is performed once or more (predetermined number of times), that is, steps 1b and 2b are alternately performed one or more times (predetermined number of times). Further, as the second W film, a film composed of W having a predetermined thickness, that is, a W film that is a film containing W as a main component can be formed. That is, a W film having a predetermined thickness formed by laminating the first W film and the second W film in this order as a film containing W can be formed on the base film on the surface of the wafer 200. Note that the W film formed by laminating the first W film and the second W film is a film composed of W alone, that is, a film containing W as a main component. The above cycle is preferably repeated multiple times. That is, it is preferable that the thickness of the second W layer formed per cycle is made smaller than the desired film thickness and the above-described cycle is repeated a plurality of times until the desired film thickness is obtained.

(Heat treatment process)
Subsequently, the W film formed on the base film on the surface of the wafer 200 is heat-treated. Here, the energization amount to the heater 207 is adjusted so that the temperature of the wafer 200 is 600 ° C. or higher, for example, 800 to 850 ° C., and the W film is heat-treated (annealed). The annealing process is performed in an inert gas atmosphere such as N ₂ gas. The annealing treatment time is, for example, a predetermined time within a range of 1 to 120 seconds. By performing the annealing process, the crystal state of the W film formed on the base film on the surface of the wafer 200 can be changed to a desired crystal state, and the crystal state can be stabilized. Further, impurities remaining in the W film can be eliminated. That is, the W film can be modified by annealing. Also, the W film can be densified by annealing.

  In this embodiment, an example in which the W film forming process (the first W film forming process and the second W film forming process) and the heat treatment process are performed in the same processing chamber 201 (in-situ). Although described, the W film forming step and the heat treatment step can be performed in different processing chambers (ex-situ). If both processes are performed in-situ, the wafer 200 can be consistently processed while being kept under vacuum without being exposed to the air, and a stable film forming process can be performed. it can. If both processes are performed ex-situ, the temperature in each processing chamber can be set in advance, for example, to the processing temperature in each process or a temperature close thereto, thereby shortening the time required for temperature adjustment and improving production efficiency. Can be increased.

(Purge and return to atmospheric pressure)
When the annealing process on the wafer 200 is completed, the valves 243d and 243e are opened, N ₂ gas as an inert gas is supplied into the processing chamber 201 from each of the gas supply pipes 232d and 232e, and exhausted from the exhaust pipe 231. The N ₂ gas acts as a purge gas, whereby the inside of the processing chamber 201 is purged with an inert gas, and the gas and reaction byproducts remaining in the processing chamber 201 are removed from the processing chamber 201 (purge). Thereafter, 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 returned to normal pressure (return to atmospheric pressure).

(Boat unload and wafer discharge)
Thereafter, the seal cap 219 is lowered by the boat elevator 115 to open the lower end of the reaction tube 203, and the processed wafer 200 is supported by the boat 217 from the lower end of the reaction tube 203 to the outside of the reaction tube 203. Unloaded (boat unload). Thereafter, the processed wafer 200 is taken out from the boat 217 (wafer discharge).

(3) Effects according to the present embodiment According to the present embodiment, the following one or more effects are achieved.

(A) According to the present embodiment, the first source gas (WCl ₆ gas) that does not contain F (F-free) is supplied to the wafer 200, and the first has reducibility with respect to the wafer 200. The first W film is formed on the base film on the surface of the wafer 200 by performing a predetermined number of cycles including the step of supplying the reactive gas (B ₂ H ₆ gas). That is, the first W film is formed without supplying a gas containing F to the wafer 200. Thereby, it can be avoided that F is supplied to the base film on the surface of the wafer 200, and etching of the base film on the surface of the wafer 200 due to F can be prevented.

Further, according to the present embodiment, after the first W film is formed on the base film on the surface of the wafer 200, the second source gas (WF ₆ gas) containing F is supplied to the wafer 200; And supplying a _second reactive gas (B ₂ H ₆ gas) having reducibility to the wafer 200, a second W film is formed on the first W film by performing a cycle including a predetermined number of times. Form. Further, the thickness of the first W film is set to be 1 atomic layer or more, preferably 1 nm or more, more preferably 5 nm or more. That is, when the second W film forming step is performed, the base film on the surface of the wafer 200 is covered with the first W film that is a continuous film without being exposed. Accordingly, it is possible to prevent the WF ₆ gas from being directly supplied to the base film on the surface of the wafer 200 in the second W film forming step, and the WF ₆ gas, that is, the F contained in the WF ₆ gas. It becomes possible to prevent etching of the underlying film on the surface of the wafer 200 due to the above.

  As described above, according to the present embodiment, when the W film is formed on the wafer 200 using the source gas containing F, it is possible to prevent the etching of the underlayer for film formation, that is, the underlayer film on the surface of the wafer 200. It becomes possible. And it becomes possible to suppress peeling from the foundation | substrate of film-forming of the formed W film | membrane. In addition, it is possible to improve the in-plane film thickness uniformity of the W film and improve the flatness of the W film surface. This effect is particularly effective when the film forming process is performed using a Si-containing film or the like that is easily etched by F as a base for film formation.

(B) In the first W film according to this embodiment, F contained in the second source gas (WF ₆ gas) diffuses (moves) to the base film on the surface of the wafer 200 in the second W film forming step. It acts to suppress this. Further, in the first W film, F contained in the second W film is diffused (moved) in the base film on the surface of the wafer 200 even in the step of heat-treating the W film formed on the base film on the surface of the wafer 200. It acts to suppress this. In other words, the first W film acts as a diffusion suppression film (barrier film) for F in the second W film formation process and the heat treatment process.

  As described above, according to the present embodiment, when a W film is formed on the wafer 200 using a source gas containing F, diffusion of F to the base film on the surface of the wafer 200 that serves as a base for film formation is prevented. It becomes possible. As a result, the influence of F on the film formation base can be reduced. For example, when a W film is formed using an insulating film (metal insulating film) such as an AlO film or an HfO film as a base for film formation, the diffusion of F into the insulating film is prevented, thereby insulating the insulating film. It becomes possible to suppress a decrease in property.

(C) According to the present embodiment, the first source gas (WCl ₆ gas) and the first reaction gas (B ₂ H ₆ gas) are alternately supplied to the wafer 200 by the alternate supply method. 1 W film is formed. By using the alternate supply method, the above-described F diffusion suppression effect by the first W film can be improved compared to the case of using the simultaneous supply method in which WCl ₆ gas and B ₂ H ₆ gas are simultaneously supplied to the wafer 200 ( (Barrier effect) can be improved. As a result, it is possible to more reliably prevent F from diffusing into the base film on the surface of the wafer 200 in the second W film forming step and the heat treatment step.

(D) According to the present embodiment, an inorganic gas, that is, a C-free gas is used as the first source gas. As a result, impurities such as C can be prevented from being mixed into the first W film, the impurity concentration of the W film can be reduced, and a decrease in the conductivity of the W film can be avoided.

The first source gas is preferably not only free of C but also free of O. That is, the first source gas is preferably a gas containing no C and O. By using such a gas, the entry of impurities such as C and O into the first W film can be prevented, the concentration of impurities in the W film can be further reduced, and the conductivity of the W film can be reduced. Even more avoidance is possible. In addition, by using an O-free gas, the first W film and the underlying film on the surface of the wafer 200 can be prevented from being oxidized. Note that the WCl ₆ gas used as the first source gas in the present embodiment is not only free of C but also free of O.

Further, it is more preferable that the first source gas is not C-free but also N-free, H-free, and O-free. That is, the first source gas is more preferably a gas containing no C, N, H and O. By using such a gas, impurities such as C, N, H, and O can be prevented from being mixed into the first W film, the concentration of impurities in the W film can be further reduced, and the conductivity of the W film can be reduced. It is possible to further avoid the deterioration of the property. Further, by using N-free gas, it is possible to prevent nitridation of the first W film and the underlying film on the surface of the wafer 200, respectively. In addition, by using an O-free gas, the first W film and the underlying film on the surface of the wafer 200 can be prevented from being oxidized. Note that the WCl ₆ gas used as the first source gas in the present embodiment is not only C-free, but also N-free, H-free, and O-free.

(E) According to the present embodiment, in step 2a, the W-containing layer containing Cl and B ₂ H ₆ gas are reacted to extract or remove impurities such as Cl from the W-containing layer containing Cl. Can be separated. Thereby, the impurity concentration in the first W layer, that is, the first W film can be reduced. In step 2b, by reacting the W-containing layer containing F with the B ₂ H ₆ gas, impurities such as F can be extracted or desorbed from the W-containing layer containing F. Thereby, the impurity concentration in the second W layer, that is, the second W film can be reduced. As a result, it is possible to reduce the impurity concentration of the W film and avoid a decrease in the conductivity of the W film.

(F) According to the present embodiment, a C-free hydrogen-containing gas, that is, an inorganic hydrogen-containing gas is used as the first reaction gas and the second reaction gas, respectively. As a result, impurities such as C can be prevented from being mixed into the first W film and the second W film, respectively, the impurity concentration of the W film can be reduced, and the conductivity decrease of the W film can be avoided. Is possible.

(G) According to this embodiment, the first W film formation step and the second W film formation step are performed in the same processing chamber 201 with the temperature of the wafer 200 set to the same temperature. That is, according to the present embodiment, it is not necessary to provide a temperature adjustment time (waiting time) between the first W film forming process and the second W film forming process. Thereby, the total time required for forming the W film can be shortened, and the total productivity of the substrate processing can be improved.

(H) According to the present embodiment, after the first W film is formed using WCl ₆ gas and B ₂ H ₆ gas, the _second W is formed using WF ₆ gas and B ₂ H ₆ gas. A film is formed. That is, WCl ₆ gas is used as the source gas at the initial stage of the film forming process, and thereafter, the source gas is switched to WF ₆ gas. As a result, the total productivity of the W film can be improved. In other words, the film formation rate of the W film using the WF ₆ gas having relatively high reactivity is higher than the film formation rate of the W film using the relatively mild WCl ₆ gas. Thus, it is possible to improve the productivity of the film formation process as compared with the case where the film formation is performed using only the WCl ₆ gas as the source gas. In addition, since the cost of the WCl ₆ gas is higher than that of the WF ₆ gas, in this embodiment, the film formation cost can be reduced as compared with the case where the film formation is performed using only the WCl ₆ gas as the source gas. It becomes possible.

  It should be noted that these effects are more prominent by making the film formation time for forming the first W film shorter than the film formation time for forming the second W film. That is, by making the film thickness of the first W film smaller (thinner) than the film thickness of the second W film, these effects are more prominent. In this case, when the thickness of the first W film is not less than 1 atomic layer, preferably not less than 1 nm and not more than 15 nm, more preferably not less than 5 nm and not more than 10 nm, these effects are further remarkably generated. It will be.

(I) According to this embodiment, the first W film and the second W film are formed by the alternate supply method in which the source gas and the reaction gas are alternately supplied to the wafer 200, respectively. Thereby, the film-forming process of a 1st W film | membrane and a 2nd W film | membrane can be suitably advanced on the conditions where surface reaction predominates, respectively. As a result, the step coverage (step coverage characteristic) of the W film can be improved, and the controllability of the W film thickness control can be improved.

<Other Embodiments of the Present Invention>
The embodiment of the present invention has been specifically described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention, as in the following modifications.

(Modification 1)
For example, in the above-described embodiment, an example in which B ₂ H ₆ gas, that is, a gas containing no metal element (W) is used as the first reaction gas and the second reaction gas has been described. However, the present invention is not limited to such a form. For example, a gas containing W and an amino group, that is, an aminotungsten-based gas may be used as at least one of the first reaction gas and the second reaction gas. As the aminotungsten-based gas, for example, hexadimethylaminoditungsten (W ₂ [N (CH ₃ ) ₂ ] ₆ ) gas can be used.

When W ₂ [N (CH ₃ ) ₂ ] ₆ gas is used as the first reaction gas, in step 2a, W ₂ [N (CH ₃ ) ₂ ] is applied to the W-containing layer containing Cl formed in step 1a. Supply ₆ gases. W ₂ [N (CH ₃ ) ₂ ] ₆ gas is supplied from the gas supply pipe 232b into the processing chamber 201 through the MFC 241b, the valve 243b, and the nozzle 249b. The processing procedure and processing conditions at this time can be the same as the processing procedure and processing conditions in step 2a of the above-described embodiment. In this case, the gas supply pipe 232b, the MFC 241b, and the valve 243b constitute an amino tungsten-based gas supply system as the first reaction gas supply system. The nozzle 249b may be included in the aminotungsten gas supply system.

By supplying W ₂ [N (CH ₃ ) ₂ ] ₆ gas to the wafer 200 under the above-described conditions, the W-containing layer containing Cl and formed on the wafer 200 in Step 1a and W ₂ [N ( CH ₃ ) ₂ ] ₆ gas reacts. That is, by supplying W ₂ [N (CH ₃ ) ₂ ] ₆ gas to the wafer 200 heated to the above temperature, an amino group is contained from W in the W ₂ [N (CH ₃ ) ₂ ] ₆ gas. The ligand is separated, and the separated ligand reacts with Cl in the W-containing layer containing Cl to extract Cl from the W-containing layer containing Cl. Further, the W in the W ₂ [N (CH ₃ ) ₂ ] ₆ gas is separated, and W which has dangling bonds is contained in the W-containing layer from which Cl is extracted and is not bonded. A W-W bond is formed by combining with W that has a hand or W that has an unbonded hand. At this time, under the above-described conditions, the ligand separated from W in the W ₂ [N (CH ₃ ) ₂ ] ₆ gas is inhibited from binding to W in the W-containing layer containing Cl. As a result, the W-containing layer containing Cl formed on the wafer 200 in Step 1a is the first layer (first W layer) containing W and having a very small content of impurities such as Cl, C, and N. To (modified). The first W layer is a layer formed of simple W having a thickness of less than one atomic layer to several atomic layers.

When the first W layer is formed, Cl contained in the W-containing layer containing Cl before modification and an amino group contained in the W ₂ [N (CH ₃ ) ₂ ] ₆ gas are included. The ligand reacts in the process of reforming the W-containing layer containing Cl with W ₂ [N (CH ₃ ) ₂ ] ₆ gas, constitutes a gaseous reaction product such as an amino salt, and the exhaust pipe It is discharged from the processing chamber 201 through the H.231. This makes it possible to reduce the amount of impurities such as Cl, C, and N contained in the W-containing layer containing modified Cl, that is, the first W layer.

When W ₂ [N (CH ₃ ) ₂ ] ₆ gas is used as the second reaction gas, in Step 2b, W ₂ [N (CH ₃ ) ₂ ] is applied to the W-containing layer containing F formed in Step 1b. Supply ₆ gases. W ₂ [N (CH ₃ ) ₂ ] ₆ gas is supplied from the gas supply pipe 232b into the processing chamber 201 through the MFC 241b, the valve 243b, and the nozzle 249b. The processing procedure and processing conditions at this time can be the same as the processing procedure and processing conditions in step 2b of the above-described embodiment. In this case, the gas supply pipe 232b, the MFC 241b, and the valve 243b constitute an aminotungsten-based gas supply system as the second reaction gas supply system. The nozzle 249b may be included in the aminotungsten gas supply system.

By supplying W ₂ [N (CH ₃ ) ₂ ] ₆ gas to the wafer 200 under the above-described conditions, the W-containing layer containing F and W ₂ formed on the first W film in Step 1b. [N (CH ₃ ) ₂ ] ₆ gas reacts. That is, by supplying W ₂ [N (CH ₃ ) ₂ ] ₆ gas to the wafer 200 heated to the above temperature, an amino group is contained from W in the W ₂ [N (CH ₃ ) ₂ ] ₆ gas. The ligand is separated, and the separated ligand reacts with F in the W-containing layer containing F to extract F from the W-containing layer containing F. Further, the W in the W ₂ [N (CH ₃ ) ₂ ] ₆ gas is separated, and W which has dangling bonds is contained in the W-containing layer from which F has been extracted and is not bonded. A W-W bond is formed by combining with W that has a hand or W that has an unbonded hand. At this time, under the above-described conditions, the ligand separated from W in the W ₂ [N (CH ₃ ) ₂ ] ₆ gas is inhibited from binding to W in the W-containing layer containing F. As a result, the W-containing layer containing F formed on the first W film in Step 1b includes the second layer (the second layer containing W and containing very little impurities such as F, C, and N). W layer) (modified). The second W layer is a layer composed of simple W having a thickness of less than one atomic layer to several atomic layers.

When forming the second W layer, it includes F contained in the W-containing layer containing F before modification, and an amino group contained in W ₂ [N (CH ₃ ) ₂ ] ₆ gas. The ligand reacts in the process of reforming the W-containing layer containing F by W ₂ [N (CH ₃ ) ₂ ] ₆ gas, constitutes a gaseous reaction product such as an amino salt, and the exhaust pipe It is discharged from the processing chamber 201 through the H.231. This makes it possible to reduce the amount of impurities such as F, C, and N contained in the W-containing layer containing F after modification, that is, the second W layer.

FIG. 5B is a diagram illustrating gas supply timings in a film forming sequence using W ₂ [N (CH ₃ ) ₂ ] ₆ gas as the first reaction gas and the second reaction gas, respectively. Even in this case, the same effects as those of the above-described embodiment can be obtained. Further, in the first W film forming step and the second W film forming step, the first W film is formed by performing film formation using two types of tungsten sources (double tungsten source) in one cycle. The film formation rate of the second W film and the film formation rate of the second W film can be increased, respectively, and the productivity of the W film formation process can be further improved. When considering the entire W film forming process, since three types of tungsten sources (triple tungsten sources) are used, this film forming method is sometimes referred to as triple tungsten source deposition or triple metal source deposition. it can. On the other hand, the film formation method of the above-described embodiment can also be referred to as double tungsten source deposition or double metal source deposition.

As the aminotungsten-based gas, in addition to W ₂ [N (CH ₃ ) ₂ ] ₆ gas, hexamethylethylaminoditungsten (W ₂ [N (CH ₃ ) (C ₂ H ₃ )] ₆ ) gas, hexadiethylamino Ditungsten (W ₂ [N (C ₂ H ₃ ) ₆ ] ₆ ) gas, butyrimidobisbutylaminotungsten gas, bistaributylimidobisdimethylamidotungsten ((t-C ₄ H ₉ NH) ₂ W = (Nt -C ₄ H _{9) 2)} it is possible to use a gas or the like.

(Modification 2)
In the above-described embodiment, the example in which the process of supplying the WCl ₆ gas and the process of supplying the B ₂ H ₆ gas are alternately performed a predetermined number of times (m times) in the first W film forming process has been described. The present invention is not limited to such a form. For example, as shown in FIG. 6A, the supply of B ₂ H ₆ gas may be continuously performed, and the supply of WCl ₆ gas may be intermittently performed a plurality of times (m times). Further, for example, as shown in FIG. 6B, the supply of WCl ₆ gas may be performed continuously, and the supply of B ₂ H ₆ gas may be intermittently performed a plurality of times (m times). . Further, for example, as shown in FIG. 7, the supply of WCl ₆ gas and B ₂ H ₆ gas is intermittently performed a plurality of times, and at this time, the supply period of one of the WCl ₆ gas and B ₂ H ₆ gas is supplied. The other gas may be intermittently supplied a predetermined number of times. FIG. 7A shows an example in which the supply of WCl ₆ gas is intermittently performed a plurality of times (m times), and the supply of B ₂ H ₆ gas is intermittently performed once during the supply period of each WCl ₆ gas. Is shown. In FIG. 7B, the supply of B ₂ H ₆ gas is intermittently performed a plurality of times (m times), and the supply of WCl ₆ gas is intermittently performed once during the supply period of each B ₂ H ₆ gas. An example is shown. FIG. 7C shows an example in which the supply of the WCl ₆ gas is intermittently performed a plurality of times (m times), and the supply of the B ₂ H ₆ gas is intermittently performed twice during each WCl ₆ gas supply period. Is shown. The processing conditions at this time can be set to the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

Thus, in a first W-film forming process, it is caused to overlap the supply period of part B ₂ H ₆ gas supply period of WCl ₆ gas, also the supply period of the B ₂ H ₆ gas Even if the supply period of the WCl ₆ gas is partially overlapped, the same effect as the above-described embodiment can be obtained. In addition, when a part of the gas supply period is overlapped as described above, the film formation rate of the first W film is improved as compared with the case where the gas supply periods are alternately performed without overlapping the supply periods. As a result, the total film formation rate of the W film formed by laminating the first W film and the second W film can be improved. However, as in the film forming sequence shown in FIG. 5A, the supply of WCl ₆ gas and the supply of B ₂ H ₆ gas are alternately performed with the residual gas removal in the processing chamber 201 interposed therebetween. However, the WCl ₆ gas and the B ₂ H ₆ gas can be appropriately reacted under conditions where the surface reaction is dominant, and the film thickness controllability and step coverage can be improved. It is preferable. In addition, a gas phase reaction between WCl ₆ gas and B ₂ H ₆ gas in the processing chamber 201 can be avoided, and generation of particles in the processing chamber 201 can be suppressed.

(Modification 3)
In the above-described embodiment, the example in which the step of supplying the WF ₆ gas and the step of supplying the B ₂ H ₆ gas are alternately performed a predetermined number of times (n times) in the second W film forming step has been described. The present invention is not limited to such a form.

For example, as shown in FIG. 6 (a), B ₂ H continuously perform supply of ₆ gas, while intermittently a plurality of times the supply of WF ₆ gas (n times) may be performed. Further, for example, as shown in FIG. 6B, the WF ₆ gas may be continuously supplied, and the B ₂ H ₆ gas may be intermittently supplied a plurality of times (n times) during that time. . Further, for example, as shown in FIG. 7, the supply of WF ₆ gas and B ₂ H ₆ gas is intermittently performed a plurality of times, and at this time, one of the WF ₆ gas and B ₂ H ₆ gas is supplied. The other gas may be intermittently supplied a predetermined number of times. FIG. 7A shows an example in which the supply of WF ₆ gas is intermittently performed a plurality of times (n times), and the supply of B ₂ H ₆ gas is intermittently performed once during each WF ₆ gas supply period. Is shown. In FIG. 7B, the supply of B ₂ H ₆ gas is intermittently performed a plurality of times (n times), and the supply of WF ₆ gas is intermittently performed once during the supply period of each B ₂ H ₆ gas. An example is shown. FIG. 7C shows an example in which the supply of WF ₆ gas is intermittently performed a plurality of times (n times), and the supply of B ₂ H ₆ gas is intermittently performed twice during each WF ₆ gas supply period. Is shown. The processing conditions at this time can be set to the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

As described above, in the second W film formation step, even if the B ₂ H ₆ gas supply period overlaps with a part of the WF ₆ gas supply period, the B ₂ H ₆ gas supply period Even if the supply period of the WF ₆ gas is partially overlapped, the same effect as the above-described embodiment can be obtained. In addition, when a part of the gas supply period is overlapped as described above, the deposition rate of the second W film is improved as compared with the case where the gas supply periods are alternately performed without overlapping the supply periods. As a result, the total film formation rate of the W film formed by laminating the first W film and the second W film can be improved. However, as in the film forming sequence shown in FIG. 5A, the supply of WF ₆ gas and the supply of B ₂ H ₆ gas are alternately performed with the residual gas removal in the processing chamber 201 interposed therebetween. However, the WF ₆ gas and the B ₂ H ₆ gas can be appropriately reacted under conditions where the surface reaction is dominant, and the controllability of the film thickness control and the step coverage can be improved. It is preferable. Further, it is preferable in that the gas phase reaction between the WF ₆ gas and the B ₂ H ₆ gas in the processing chamber 201 can be avoided, and generation of particles in the processing chamber 201 can be suppressed.

(Modification 4)
In the above-described embodiment, the example in which the first W film and the second W film are formed by the alternate supply method in which the source gas and the reaction gas are alternately supplied has been described. It is not limited.

For example, as shown in FIG. 8A, the first W film is formed by a simultaneous supply method in which the step of supplying the WCl ₆ gas and the step of supplying the B ₂ H ₆ gas are simultaneously performed a plurality of times (m times). Alternatively, the second W film may be formed by a simultaneous supply method in which the step of supplying WF ₆ gas and the step of supplying B ₂ H ₆ gas are simultaneously performed a plurality of times (n times). Further, as shown in FIG. 8B, the first W film is formed by the simultaneous supply method in which the step of supplying the WCl ₆ gas and the step of supplying the B ₂ H ₆ gas are performed once at the same time. The second W film may be formed by a simultaneous supply method in which the step of supplying WF ₆ gas and the step of supplying B ₂ H ₆ gas are performed once at the same time. The processing conditions at this time can be set to the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

  In this way, in the first W film forming step and the second W film forming step, the supply period of the source gas and the reactive gas may be supplied simultaneously, that is, the supply periods of these gases are overlapped. Even if it does, the effect similar to the above-mentioned embodiment is acquired. In addition, when the gas supply periods are overlapped as described above, the film formation rates of the first W film and the second W film are compared with the case where the gas supply periods are alternately performed without overlapping the supply periods. As a result, it is possible to improve the total film formation rate of the W film in which the first W film and the second W film are stacked. However, as in the film forming sequence shown in FIG. 5A, it is more preferable to supply the source gas and the reaction gas alternately with the residual gas removal in the processing chamber 201 between them. And reactive gas can be appropriately reacted under conditions in which the surface reaction is dominant, and the controllability of film thickness control can be improved. In addition, a gas phase reaction between the source gas and the reaction gas in the processing chamber 201 can be avoided, and the generation of particles in the processing chamber 201 can be suppressed.

(Modification 5)
The film forming sequences shown in FIGS. 5 to 8 can be arbitrarily combined. That is, any one of the film forming sequences shown in FIGS. 5A, 5B, 6A, 6B, 7A to 7C, and 8A, 8B. 5 (a), (b), FIGS. 6 (a), (b), FIGS. 7 (a)-(c), FIGS. The second W film forming step shown in any of the film forming sequences shown in b) can be performed in any combination. The processing conditions at this time can be set to the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

  For example, the wafer is formed by combining the first W film forming step of the film forming sequence shown in FIG. 5A and the second W film forming step of the film forming sequence shown in FIG. A W film formed by laminating a first W film and a second W film may be formed on 200. Further, for example, the first W film forming step of the film forming sequence shown in FIG. 5A and the second W film forming step of the film forming sequence shown in FIG. 8A are performed in combination. A W film formed by laminating a first W film and a second W film may be formed on the wafer 200. In these cases, as compared with the case where the W film formed by laminating the first W film and the second W film is formed by the film forming sequence shown in FIG. The film rate can be increased. Compared to the case where the W film formed by laminating the first W film and the second W film is formed by the film forming sequence shown in FIG. 6A or FIG. The total film thickness controllability and step coverage can be improved.

(Modification 6)
In the above-described embodiment, the example in which the first reaction gas and the second reaction gas are the same type of gas (the gas having the same chemical structure) has been described. That is, the first reaction gas and the second reaction gas may be different types of gases (gases having different chemical structures). For example, as the first reaction gas, an inorganic borane-based gas, an inorganic silane-based gas, an inorganic hydrogen-containing gas such as H ₂ gas, or an aminotungsten-based gas is used. Another type of gas different from that may be used as the gas.

  The type of reaction gas used in each step of the first W film forming step and the second W film forming step, the film forming sequence used in each step, and the like are the type of source gas, the temperature of the wafer 200, and the formation attempt. It can be appropriately selected depending on the characteristics of the film.

For example, when WCl ₆ gas is used as the first source gas, B ₂ is used as the first reaction gas when an inorganic silane-based gas such as Si ₂ H ₆ gas or H ₂ gas is used as the first reaction gas. An appropriate reaction can be generated and may be preferable to using an inorganic borane-based gas such as H ₆ gas.

In particular, when WCl ₆ gas is used as the first source gas, non-plasma is better when Si ₂ H ₆ gas is used as the first reaction gas than when B ₂ H ₆ gas is used as the first reaction gas. In some cases, the first W film can be easily formed in the atmosphere. In this case, the first W film is formed by alternately performing the process of supplying the WCl ₆ gas and the process of supplying the Si ₂ H ₆ gas, or by performing these processes simultaneously. Can do. However, alternately performing these steps can cause a more appropriate reaction than when these steps are performed simultaneously.

Further, when WCl ₆ gas is used as the first source gas, the non-plasma atmosphere is better when H ₂ gas is used as the first reaction gas than when B ₂ H ₆ gas is used as the first reaction gas. The formation of the first W film below may be facilitated. In this case, it is possible to generate a more appropriate reaction by simultaneously performing the step of supplying the WCl ₆ gas and the step of supplying the H ₂ gas than when these steps are alternately performed. However, when H ₂ gas is used as the first reaction gas, the temperature of the wafer 200 needs to be higher than when Si ₂ H ₆ gas is used as the first reaction gas. In some cases, the underlying film on the surface of the wafer 200 may be damaged by Cl, and the reliability of the semiconductor device may be reduced.

For example, when WF ₆ gas is used as the second source gas, the second reaction gas is not only an inorganic borane gas such as B ₂ H ₆ gas but also an inorganic silane gas such as Si ₂ H ₆ gas. Alternatively, H ₂ gas or the like can be suitably used.

When WF ₆ gas is used as the second source gas and Si ₂ H ₆ gas is used as the second reaction gas, as in the case of using B ₂ H ₆ gas as the second reaction gas, in a non-plasma atmosphere. A second W film can be formed. In this case, the step of supplying the WF ₆ gas and the step of supplying the Si ₂ H ₆ gas or the B ₂ H ₆ gas may be performed alternately, or these steps may be performed simultaneously. A W film can be formed. In addition, when these steps are alternately performed, a more appropriate reaction can be caused than when these steps are performed simultaneously.

In addition, when WF ₆ gas is used as the second source gas and H ₂ gas is used as the second reaction gas, as in the case of using B ₂ H ₆ gas as the second reaction gas, in a non-plasma atmosphere. A second W film can be formed. In this case, it is possible to generate a more appropriate reaction by simultaneously performing the step of supplying the WF ₆ gas and the step of supplying the H ₂ gas than when these steps are alternately performed.

Note that the resistivity of the W film increases (increases) in the order of using H ₂ gas as a reaction gas, using B ₂ H ₆ gas, and using Si ₂ H ₆ gas. That is, the resistivity of the W film is lowest (smaller) when H ₂ gas is used as the reaction gas. That is, by using H ₂ gas as the second reaction gas, the total resistivity of the W film formed by stacking the first W film and the second W film can be reduced. Further, by using H ₂ gas as each of the first reaction gas and the second reaction gas, the total resistivity of the W film in which the first W film and the second W film are laminated, It can be further reduced.

However, when WF ₆ gas is used as the second source gas and H ₂ gas is used as the second reaction gas, for example, in a low temperature region of about 200 to 250 ° C., depending on the type of the underlying film (TiN, SiO, Si, etc.) May be difficult to form a film. On the other hand, for example, WCl ₆ gas is used as the first source gas, Si ₂ H ₆ gas is used as the first reaction gas, and the first W film formed by reacting these is used as the base film. In this case, the second W film can be formed using the WF ₆ gas as the second source gas and the H ₂ gas as the second reaction gas even in the low temperature region described above. At this time, even if a trench having an aspect ratio of, for example, about 10 is formed on the surface of the wafer 200 surface, the first W film and the second W film can be formed as continuous films. Further, the step coverage can be made good (practical level).

From the above, in order to form a low resistivity W film without increasing the temperature of the wafer 200,
A step of supplying WCl ₆ gas as the first source gas to the wafer 200 and a step of supplying Si ₂ H ₆ gas as the first reaction gas to the wafer 200 are alternately performed a predetermined number of times. Forming a first W film on the wafer 200;
By simultaneously performing the step of supplying WF ₆ gas as the second source gas to the wafer 200 and the step of supplying H ₂ gas as the second reaction gas to the wafer 200, the first W Forming a second W film on the film;
It can be seen that it is effective to form a W film in which the first W film and the second W film are stacked.

(Modification 7)
Further, in the above-described embodiment, an example in which a film containing W that is a transition metal element is formed has been described. The present invention is not limited to the above-described embodiment. For example, transition metal elements such as titanium (Ti), molybdenum (Mo), tantalum (Ta), ruthenium (Ru), hafnium (Hf), aluminum (Al), and the like The present invention can also be suitably applied to the formation of a metal thin film containing a typical metal element.

For example, in the case of forming a Ti film composed of, for example, Ti alone as a film containing Ti, a gas containing Ti and a chloro group (Cl) such as titanium tetrachloride (TiCl ₄ ) as the first source gas ( A gas (fluorotitanium-based gas) containing Ti and a fluoro group (F) such as titanium tetrafluoride (TiF ₄ ) can be used as the second source gas. As the first reaction gas and the second reaction gas, tetrakisethylmethylaminotitanium (Ti [N (C ₂ H ₅ ) (CH ₃ )] ₄ , in addition to the reaction gas described in the above embodiment, is abbreviated. : TEMAT) or other gas containing an amino group and an amino group (amino titanium-based gas) can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, when a Mo film composed of, for example, Mo alone is formed as a film containing Mo, a gas containing Mo and a chloro group (chloromolybdenum) such as molybdenum pentachloride (MoCl ₅ ) is used as the first source gas. As the second source gas, a gas containing Mo and a fluoro group (fluoromolybdenum gas) such as molybdenum pentafluoride (MoF ₅ ) can be used. As the first reaction gas and the second reaction gas, in addition to the reaction gas shown in the above embodiment, a gas containing Mo and an amino group (amino molybdenum-based gas) can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, when forming a Ta film composed of Ta alone as a film containing Ta, for example, a gas containing Ta and a chloro group such as tantalum pentachloride (TaCl ₅ ) (chlorotantalum) as the first source gas. As the second source gas, a gas containing Ta and a fluoro group (fluorotantalum-based gas) such as tantalum pentafluoride (TaF ₅ ) can be used. Further, as the first reaction gas and the second reaction gas, in addition to the reaction gas shown in the above embodiment, a gas containing Ta and an amino group (amino tantalum-based gas) can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, in the case of forming a Ru film composed of, for example, Ru alone as a film containing Ru, a gas containing Ru and a chloro group (chlororuthenium) such as ruthenium trichloride (RuCl ₃ ) as the first source gas. As the second source gas, a gas containing Ru and a fluoro group (fluororuthenium-based gas) such as ruthenium trifluoride (RuF ₃ ) can be used. Further, as the first reaction gas and the second reaction gas, in addition to the reaction gas shown in the above embodiment, a gas containing Ru and an amino group (aminoruthenium-based gas) can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, when a Hf film made of Hf alone is formed as a film containing Hf, for example, a gas containing Hf and a chloro group (chlorohafnium) such as hafnium tetrachloride (HfCl ₄ ) as the first source gas. As the second source gas, a gas containing Hf and a fluoro group (fluorohafnium gas) such as hafnium tetrafluoride (HfF ₄ ) can be used. As the first reaction gas and the second reaction gas, tetrakisethylmethylaminohafnium (Hf [N (C ₂ H ₅ ) (CH ₃ )] ₄ , in addition to the reaction gas shown in the above embodiment, is abbreviated. : TEMAH) or other gas containing Hf and an amino group (aminohafnium-based gas) can be used. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

Further, for example, when an Al film composed of Al alone, for example, is formed as a film containing Al, a gas containing Al and a chloro group (chloroaluminum) such as aluminum trichloride (AlCl ₃ ) is used as the first source gas. As the second source gas, a gas containing Al and a fluoro group (fluoroaluminum-based gas) such as aluminum trifluoride (AlF ₃ ) can be used. Further, as the first reaction gas and the second reaction gas, an organoaluminum gas such as trimethylaluminum (Al (CH ₃ ) ₃ , abbreviation: TMA) is used in addition to the reaction gas shown in the above embodiment. Can do. The processing conditions at this time can be set to the same processing conditions as in the above-described embodiment, for example.

  Thus, the present invention can be applied not only to the W film that is a film containing a transition metal element, but also to the formation of a film containing a metal element such as a transition metal element other than W or a typical metal element, Even in this case, the same effect as the above-described embodiment can be obtained.

(Modification 8)
In the above-described embodiment, an example of forming a W film composed of W alone on a wafer 200 as a substrate, that is, an example of forming a film containing a metal element as a main component has been described. The form is not limited. For example, as a film containing W on the wafer 200, for example, a tungsten nitride film (WN film), a tungsten oxide film (WO film), a tungsten oxynitride film (WON film), a tungsten-titanium alloy film (WTi film), etc. The present invention can also be suitably applied when forming the film. Note that the WN film, the WO film, the WON film, and the WTi film are all conductive metal films.

For example, in the case where a metal nitride film such as a WN film is formed on the wafer 200, the wafer is used in at least one of the above-described first film forming process and the second film forming process. In addition to the process of supplying the source gas to the wafer 200 and the process of supplying the reaction gas to the wafer 200, for example, ammonia (NH ₃ ) gas is supplied to the wafer 200 as a nitriding gas, that is, a nitrogen-containing gas. A cycle that further includes a process may be performed a predetermined number of times. The supply flow rate of the NH ₃ gas can be set to a flow rate in the range of 100 to 1000 sccm, for example. Other processing conditions can be the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

Further, when a metal oxide film such as a WO film is formed on the wafer 200, the wafer is used in at least one of the above-described first film forming process and second film forming process. In addition to supplying a source gas to the wafer 200 and supplying a reaction gas to the wafer 200, for example, oxygen (O ₂ ) gas is supplied to the wafer 200 as an oxidizing gas, that is, an oxygen-containing gas. A cycle that further includes a process may be performed a predetermined number of times. The supply flow rate of the O ₂ gas can be set to a flow rate in the range of 100 to 1000 sccm, for example. Other processing conditions can be the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

Further, when a metal oxynitride film such as a WON film is formed on the wafer 200, in at least one of the above-described first film forming process and the second film forming process, In addition to the step of supplying the source gas to the wafer 200, the step of supplying the reaction gas to the wafer 200, the step of supplying, for example, NH ₃ gas as the nitrogen-containing gas to the wafer 200, and the wafer 200 In contrast, for example, a cycle that further includes a step of supplying O ₂ gas as the oxygen-containing gas may be performed a predetermined number of times. The supply flow rates of NH ₃ gas and O ₂ gas can be set to a flow rate in the range of 100 to 1000 sccm, for example. Other processing conditions can be the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

Further, when a metal alloy film such as a WTi film is formed on the wafer 200, the wafer is used in at least one of the above-described first film forming process and the second film forming process. In addition to the step of supplying the source gas to the wafer 200 and the step of supplying the reaction gas to the wafer 200, the step of supplying, for example, TiCl ₄ gas as a source gas containing another metal element to the wafer 200 is further provided. What is necessary is just to make it perform the cycle containing it predetermined times. Further, for example, the WTi film can be formed by using TiCl ₄ gas instead of WCl ₆ gas in the film forming sequence of FIG. 5B. The supply flow rate of the TiCl ₄ gas can be set to a flow rate in the range of 100 to 2000 sccm, for example. Other processing conditions can be the same processing conditions as the above-described film forming sequence described with reference to FIGS. 4 and 5A, for example.

As the nitrogen-containing gas, for example, diazene (N ₂ H ₂ ) gas, hydrazine (N ₂ H ₄ ) gas, N ₃ H ₈ gas, or the like can be used in addition to NH ₃ gas. The nitrogen-containing gas acts as an N source (nitrogen source) when forming a metal nitride film or a metal oxynitride film. As the oxygen-containing gas, in addition to O ₂ gas, for example, nitrous oxide (N ₂ O) gas, nitrogen monoxide (NO) gas, nitrogen dioxide (NO ₂ ) gas, ozone (O ₃ ) gas, hydrogen (H ₂ ) gas + O ₂ gas, H ₂ gas + O ₃ gas, water vapor (H ₂ O) gas, carbon monoxide (CO) gas, carbon dioxide (CO ₂ ) gas, or the like can be used. The oxygen-containing gas acts as an O source (oxygen source) when forming a metal oxide film or a metal oxynitride film. As a source gas containing other metal elements, TiF ₄ gas or the like can be used in addition to TiCl ₄ gas. The source gas containing other metal elements acts as a metal source (metal source) when forming the metal alloy film.

  Process recipes (programs describing processing procedures and processing conditions) used to form the above-mentioned thin film are each in accordance with the contents of the substrate processing (film type, composition ratio, film quality, film thickness, etc. of the film to be formed). It is preferable to prepare individually (preparing a plurality). And when starting a substrate processing, it is preferable to select a suitable process recipe suitably from several process recipes according to the content of a substrate processing. Specifically, the substrate processing apparatus includes a plurality of process recipes individually prepared according to the contents of the substrate processing via an electric communication line or a recording medium (external storage device 123) on which the process recipe is recorded. It is preferable to store (install) in the storage device 121c in advance. When starting the substrate processing, the CPU 121a included in the substrate processing apparatus appropriately selects an appropriate process recipe from a plurality of process recipes stored in the storage device 121c according to the content of the substrate processing. Is preferred. With this configuration, thin films with various film types, composition ratios, film qualities, and film thicknesses can be formed for general use with good reproducibility using a single substrate processing apparatus. Further, it is possible to reduce an operator's operation burden (such as an input burden of a processing procedure and a processing condition), and to quickly start substrate processing while avoiding an operation error.

  The above-described process recipe is not limited to the case of creating a new process. For example, an existing process recipe already installed in the substrate processing apparatus may be changed. When changing the process recipe, the changed process recipe may be installed in the substrate processing apparatus via an electric communication line or a recording medium recording the process recipe. Further, an existing process recipe that has already been installed in the substrate processing apparatus may be directly changed by operating the input / output device 122 provided in the existing substrate processing apparatus.

  In the above-described embodiment, an example in which a thin film is formed using a batch-type substrate processing apparatus that processes a plurality of substrates at a time has been described. The present invention is not limited to the above-described embodiment, and can be suitably applied to a case where a thin film is formed using, for example, a single wafer processing apparatus that processes one or several substrates at a time. In the above-described embodiment, an example in which a thin film is formed using a substrate processing apparatus having a hot wall type processing furnace has been described. The present invention is not limited to the above-described embodiment, and can be suitably applied to a case where a thin film is formed using a substrate processing apparatus having a cold wall type processing furnace. Even in these cases, the processing conditions can be the same processing conditions as in the above-described embodiment, for example.

  Each above-mentioned embodiment, each modification, etc. can be used combining suitably. Further, the processing conditions at this time can be the same processing conditions as in the above-described embodiment, for example.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

(Appendix 1)
According to one aspect of the invention,
A step of supplying a first source gas which is an inorganic gas containing a metal element and containing no fluorine to the substrate; and a step of supplying a first reactive gas having reducibility to the substrate. Forming a first film containing the metal element on the substrate by performing a cycle including the predetermined number of times;
A cycle including a step of supplying a second source gas containing the metal element and fluorine to the substrate and a step of supplying a second reactive gas having a reducing property to the substrate is performed a predetermined number of times. And forming a second film containing the metal element on the first film;
By performing the above, there is provided a method for manufacturing a semiconductor device including a step of forming a film containing the metal element in which the first film and the second film are stacked on the substrate.

(Appendix 2)
A method of manufacturing a semiconductor device according to appendix 1, preferably,
The first source gas is a gas containing the metal element and chlorine (chloro group).

(Appendix 3)
A method of manufacturing a semiconductor device according to appendix 1 or 2, preferably,
The first source gas is a gas containing the metal element and containing no fluorine (fluoro group), carbon and oxygen.

(Appendix 4)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 3, preferably,
The first source gas is a gas containing the metal element and containing no fluorine (fluoro group), carbon, nitrogen, hydrogen and oxygen.

(Appendix 5)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 4, preferably,
At least one of the first reaction gas and the second reaction gas is a hydrogen-containing gas.

(Appendix 6)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 5, preferably,
At least one of the first reaction gas and the second reaction gas is a gas containing the metal element and an amino group.
Here, the first reaction gas and the second reaction gas may be the same gas (gas having the same chemical structure) or different gases (gases having different chemical structures). May be.

(Appendix 7)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 6, preferably,
The step of forming the first film and the step of forming the second film are performed in the same processing chamber with the temperature of the substrate set to the same temperature.

(Appendix 8)
A method of manufacturing a semiconductor device according to any one of appendices 1 to 7, preferably,
The first film is formed on at least one of a silicon-containing film, a metal oxide film, and a metal nitride film formed on the substrate.

(Appendix 9)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 8, preferably,
The thickness of the first film is 1 atomic layer or more and 15 nm or less, preferably 1 nm or more and 15 nm or less, more preferably 5 nm or more and 10 nm or less.

(Appendix 10)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 9, preferably,
The method further includes a step of heat-treating the first film and the second film formed on the substrate.

(Appendix 11)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 10, preferably,
In the step of forming the first film, the step of supplying the first source gas and the step of supplying the first reaction gas are alternately performed a predetermined number of times (one or more times).

(Appendix 12)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 10, preferably,
In the step of forming the first film, supply of at least one of the first source gas and the first reaction gas is performed intermittently (multiple times).
For example, the supply of the first source gas is continuously performed, and the supply of the first reaction gas is intermittently performed a plurality of times.
Further, for example, the first reaction gas is continuously supplied, and the first raw material gas is intermittently supplied a plurality of times during that time.
Further, for example, the supply of the first source gas and the supply of the first reaction gas are intermittently performed a plurality of times, and at this time, one of the first source gas and the first reaction gas is supplied. During the gas supply period, the other gas is intermittently supplied a predetermined number of times (one or more times).

(Appendix 13)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 10, preferably,
In the step of forming the first film, the step of supplying the first source gas and the step of supplying the first reaction gas are simultaneously performed a predetermined number of times (one or more times).

(Appendix 14)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 13, preferably,
In the step of forming the second film, the step of supplying the second source gas and the step of supplying the second reaction gas are alternately performed a predetermined number of times (one or more times).

(Appendix 15)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 13, preferably,
In the step of forming the second film, supply of at least one of the second source gas and the second reaction gas is performed intermittently (multiple times).
For example, the supply of the second source gas is continuously performed, and the supply of the second reaction gas is intermittently performed a plurality of times.
Further, for example, the second reaction gas is continuously supplied, and the second raw material gas is intermittently supplied a plurality of times during that time.
Further, for example, the supply of the second source gas and the supply of the second reaction gas are intermittently performed a plurality of times, and at this time, one of the second source gas and the second reaction gas During the gas supply period, the other gas is intermittently supplied a predetermined number of times (one or more times).

(Appendix 16)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 13, preferably,
In the step of forming the second film, the step of supplying the second source gas and the step of supplying the second reaction gas are simultaneously performed a predetermined number of times (one or more times).

(Appendix 17)
A method for manufacturing a semiconductor device according to any one of appendices 1 to 16, preferably,
The film containing the metal element is a film composed of the metal element alone (a film containing the metal element as a main component).

(Appendix 18)
According to another aspect of the invention,
A step of supplying a first source gas which is an inorganic gas containing a metal element and containing no fluorine to the substrate; and a step of supplying a first reactive gas having reducibility to the substrate. Forming a first film containing the metal element on the substrate by performing a cycle including the predetermined number of times;
A cycle including a step of supplying a second source gas containing the metal element and fluorine to the substrate and a step of supplying a second reactive gas having a reducing property to the substrate is performed a predetermined number of times. And forming a second film containing the metal element on the first film;
By performing the above, there is provided a substrate processing method including a step of forming a film containing the metal element formed by stacking the first film and the second film on the substrate.

(Appendix 19)
According to yet another aspect of the invention,
A processing chamber for accommodating the substrate;
A first source gas supply system that supplies a first source gas that is an inorganic gas containing a metal element and not containing fluorine into the processing chamber;
A second source gas supply system for supplying a second source gas containing the metal element and fluorine into the processing chamber;
A first reactive gas supply system for supplying a reducing first reactive gas into the processing chamber;
A second reactive gas supply system for supplying a second reactive gas having reducing properties into the processing chamber;
By performing a predetermined number of cycles including a process of supplying the first source gas to the substrate in the processing chamber and a process of supplying the first reaction gas to the substrate in the processing chamber. A process for forming a first film containing the metal element on the substrate, a process for supplying the second source gas to the substrate in the process chamber, and a process for supplying the second source gas to the substrate in the process chamber. And a process of forming the second film containing the metal element on the first film by performing a cycle including the process of supplying the second reaction gas a predetermined number of times. The first source gas supply system and the second source gas supply system are formed on the substrate so as to form a film containing the metal element formed by laminating the first film and the second film. , Controlling the first reaction gas supply system and the second reaction gas supply system And so that made the control unit,
A substrate processing apparatus is provided.

(Appendix 20)
A procedure of supplying a first source gas, which is an inorganic gas containing a metal element and not containing fluorine, to a substrate in the processing chamber, and a first reactive gas having a reducing property to the substrate in the processing chamber And a step of forming a first film containing the metal element on the substrate by performing a cycle including a predetermined number of times, and
A procedure for supplying a second source gas containing the metal element and fluorine to the substrate in the processing chamber; and a procedure for supplying a second reactive gas having a reducing property to the substrate in the processing chamber; A step of forming a second film containing the metal element on the first film by performing a cycle including a predetermined number of times,
By performing the above, a program for causing a computer to execute a procedure for forming the film containing the metal element formed by laminating the first film and the second film on the substrate, and the program is recorded A computer readable recording medium is provided.

121 Controller (control unit)
200 wafer (substrate)
201 processing chamber 202 processing furnace 203 reaction tube 207 heater 231 exhaust pipe 232a to 232e gas supply pipe

Claims (14)

A step of supplying a first source gas, which is a non-fluorine-containing inorganic gas containing a metal element, to the substrate; and a step of reducing the substrate during the supply period of the first source gas. Forming a first film containing the metal element on the substrate by performing a cycle including a step of intermittently supplying one reactive gas a plurality of times a predetermined number of times,
Supplying a second source gas containing the metal element and fluorine to the substrate; and intermittently supplying a second reaction gas having reducibility to the substrate during the supply period of the second source gas. Forming a second film containing the metal element on the first film by performing a cycle including a step of supplying a plurality of times in a predetermined number of times, and
A method of manufacturing a semiconductor device, comprising: forming a film containing the metal element formed by stacking the first film and the second film on the substrate.   2. The semiconductor device according to claim 1, wherein in the step of forming the first film, the supply of the first source gas is continuously performed, and the supply of the first reaction gas is intermittently performed a plurality of times. Manufacturing method.   In the step of forming the first film, the supply of the first source gas and the supply of the first reaction gas are intermittently performed a plurality of times, and at this time, during the supply period of the first source gas The method for manufacturing a semiconductor device according to claim 1, wherein the supply of the first reactive gas is intermittently performed a plurality of times.   4. The method according to claim 1, wherein in the step of forming the second film, the supply of the second source gas is continuously performed, and the supply of the second reaction gas is intermittently performed a plurality of times. The manufacturing method of the semiconductor device as described in any one of Claims 1-3.   In the step of forming the second film, the supply of the second source gas and the supply of the second reaction gas are intermittently performed a plurality of times, and at this time, during the supply period of the second source gas The method for manufacturing a semiconductor device according to claim 1, wherein the second reactive gas is intermittently supplied a plurality of times.   6. The method of manufacturing a semiconductor device according to claim 1, wherein at least one of the first reaction gas and the second reaction gas is a gas containing the metal element and an amino group.   7. The gas according to claim 1, wherein one of the first reaction gas and the second reaction gas is a gas containing the metal element and an amino group, and the other gas is an inorganic hydrogen-containing gas. The manufacturing method of the semiconductor device in any one.   The method for manufacturing a semiconductor device according to claim 1, wherein both of the first reaction gas and the second reaction gas are gas containing the metal element and an amino group. The first source gas is at least one selected from the group consisting of a chlorotungsten gas, a chlorotitanium gas, a chloromolybdenum gas, a chlorotantalum gas, a chlororuthenium gas, a chlorohafnium gas, and a chloroaluminum gas. Including
The second source gas is at least one selected from the group consisting of fluorotungsten gas, fluorotitanium gas, fluoromolybdenum gas, fluorotantalum gas, fluororuthenium gas, fluorohafnium gas, and fluoroaluminum gas. Including
At least one of the first reaction gas and the second reaction gas is an aminotungsten gas, an aminotitanium gas, an aminomolybdenum gas, an aminotantalum gas, an aminoruthenium gas, or an aminohafnium gas. The method for manufacturing a semiconductor device according to claim 1, comprising at least one selected from the group consisting of a gas and an organoaluminum-based gas.   The first source gas is a chlorotungsten gas, the second source gas is a fluorotungsten gas, and at least one of the first reaction gas and the second reaction gas is: The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is an aminotungsten-based gas.   The method for manufacturing a semiconductor device according to claim 1, wherein a thickness of the first film is 5 nm or more and 15 nm or less. A processing chamber for accommodating the substrate;
A first source gas supply system that supplies a first source gas that is an inorganic gas containing a metal element and not containing fluorine into the processing chamber;
A second source gas supply system for supplying a second source gas containing the metal element and fluorine into the processing chamber;
A first reactive gas supply system for supplying a reducing first reactive gas into the processing chamber;
A second reactive gas supply system for supplying a second reactive gas having reducing properties into the processing chamber;
A process of supplying the first source gas to the substrate in the processing chamber; and intermittently supplying the first reaction gas to the substrate in the processing chamber during the supply period of the first source gas. A process including supplying a plurality of times, a process including forming the first film containing the metal element on the substrate and performing the process during the supply period of the second source gas. A cycle including a process for supplying the second source gas to the substrate in the chamber and a process for intermittently supplying the second reaction gas to the substrate in the process chamber a plurality of times is predetermined. And performing the process of forming the second film containing the metal element on the first film, so that the first film and the second film are formed on the substrate. The first raw material is formed so as to form a film containing the metal element formed by laminating Scan supply system, and the second source gas supply system, the controller configured first to control the reaction gas supply system and the second reactive gas supply system,
A substrate processing apparatus. A procedure for supplying a first source gas, which is a non-fluorine-containing inorganic gas containing a metal element, to a substrate in the processing chamber, and the substrate in the processing chamber during the supply period of the first source gas And a procedure for forming the first film containing the metal element on the substrate by performing a cycle including a procedure of intermittently supplying the first reactive gas having reducibility a plurality of times a predetermined number of times. When,
A procedure for supplying the second source gas containing the metal element and fluorine to the substrate in the processing chamber, and reducing the substrate in the processing chamber during the supply period of the second source gas. A step of intermittently supplying a second reaction gas having a plurality of times, and a step of forming a second film containing the metal element on the first film by performing a cycle including a predetermined number of times,
A program that causes a computer to execute a procedure for forming the metal element-containing film formed by stacking the first film and the second film on the substrate. A procedure for supplying a first source gas, which is a non-fluorine-containing inorganic gas containing a metal element, to a substrate in the processing chamber, and the substrate in the processing chamber during the supply period of the first source gas And a procedure for forming the first film containing the metal element on the substrate by performing a cycle including a procedure of intermittently supplying the first reactive gas having reducibility a plurality of times a predetermined number of times. When,
A procedure for supplying the second source gas containing the metal element and fluorine to the substrate in the processing chamber, and reducing the substrate in the processing chamber during the supply period of the second source gas. A step of intermittently supplying a second reaction gas having a plurality of times, and a step of forming a second film containing the metal element on the first film by performing a cycle including a predetermined number of times,
By performing the above, a computer-readable program that records a program for causing a computer to execute a procedure for forming the metal element-containing film formed by stacking the first film and the second film on the substrate is readable. recoding media.

Images