JP6061385B2 - Semiconductor device manufacturing method, substrate processing apparatus, and program - Google Patents

Description

  The present invention relates to a semiconductor device manufacturing method, a substrate processing apparatus, and a program.

  With the high integration and high performance of semiconductor devices such as MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), various types of metal films are used as electrodes and wirings. Among these, metal carbide-based or metal nitride-based metal films are often used from the viewpoint of oxidation resistance, electrical resistivity, work function, etc., for gate electrodes and DRAM (Dynamic Random Access Memory) capacitor electrodes ( Patent Document 1).

JP 2011-6783 A

  As an important parameter indicating the characteristics of the MOSFET, there is a threshold voltage (threshold voltage, Vth). This threshold voltage is determined by the work function of the electrode. The work function of the electrode can be tuned (adjusted or modulated) by the metal film constituting the electrode.

  An object of the present invention is to provide a technique capable of forming a metal film having a work function tuned to a desired value.

  According to one aspect of the present invention, a step of performing a first predetermined number of times of forming a first layer containing a metal element and nitrogen or carbon, and a second layer containing the metal element, nitrogen and carbon And a step of forming a metal film containing nitrogen and carbon at a predetermined ratio on the substrate by alternately performing a third predetermined number of times to perform the process of forming the second predetermined number of times. A method of manufacturing a device is provided.

  According to another aspect of the present invention, a step of alternately supplying a first raw material containing a metal element and a second raw material containing nitrogen or carbon to the substrate a first predetermined number of times, and the substrate In contrast, a step of supplying a third raw material containing carbon, a fourth raw material containing the metal element, and a fifth raw material containing nitrogen alternately for a second predetermined number of times are alternately performed for a third predetermined number of times. By doing so, there is provided a method for manufacturing a semiconductor device including a step of forming a metal film containing nitrogen and carbon at a predetermined ratio on the substrate.

  According to another aspect of the present invention, a metal-containing raw material containing a metal element is supplied to a processing chamber that accommodates a substrate and the substrate that is connected to the processing chamber and accommodated in the processing chamber. A metal-containing raw material supply system, connected to the processing chamber and connected to the processing chamber, a nitrogen-containing raw material supply system for supplying a nitrogen-containing raw material containing nitrogen to the substrate housed in the processing chamber, A carbon-containing raw material supply system that supplies a carbon-containing raw material containing carbon to the substrate accommodated in the processing chamber, a metal-containing raw material supply system, a nitrogen-containing raw material supply system, and a carbon-containing raw material supply system. A process of supplying the metal-containing raw material and the nitrogen-containing raw material or the carbon-containing raw material alternately for a first predetermined number of times to the substrate accommodated in the processing chamber; And nitrogen content A metal containing nitrogen and carbon at a predetermined ratio on the substrate by alternately performing the second predetermined number of times of supplying the material and the carbon-containing raw material for the third predetermined number of times. Provided is a substrate processing apparatus comprising: a control unit configured to control and execute a process for forming a film by controlling the metal-containing raw material supply system, the nitrogen-containing raw material supply system, and the carbon-containing raw material supply system. Is done.

  According to another aspect of the present invention, a procedure for performing the first predetermined number of times of the process of forming the first layer containing the metal element and nitrogen or carbon, and the first step including the metal element, nitrogen, and carbon. And a step of forming a metal film containing nitrogen and carbon in a predetermined ratio on the substrate by alternately performing a procedure of forming the second layer a second predetermined number of times and a third predetermined number of times. A program to be executed by a computer is provided.

  According to the present invention, a metal film having a work function tuned to a desired value can be formed.

It is a block diagram of the processing furnace of the substrate processing apparatus which concerns on embodiment of this invention. It is the sectional view on the AA line of FIG. It is a block diagram which shows the structure of the controller which the substrate processing apparatus shown in FIG. 1 has. It is a figure which shows the structural example of the semiconductor device to which the technique which concerns on this invention is applied. FIG. 5 is a process flowchart showing an example of a gate manufacturing process of the semiconductor device shown in FIG. 4. FIG. 6 is a process flow diagram illustrating an example of a metal film formation process in the gate manufacturing process illustrated in FIG. 5. It is a figure which shows the timing of the gas supply in the film-forming process shown in FIG. It is a figure which shows the relationship between an equivalent oxide film thickness and a flat band voltage about each of the metal film formed into Example 1-5 of this invention. It is a figure which shows the relationship between the ratio of C and N, and an effective work function about each of the metal film formed into Examples 1-5 of this invention. FIG. 10A is a diagram showing a work function with respect to the ratio of C for each of the metal films formed in Examples 1 to 5 of the present invention, and FIG. 10B is Example 1 of the present invention. It is a figure which shows the work function with respect to the ratio of N about each of the metal film formed into ~ 5.

  Next, an embodiment for carrying out the present invention will be described with reference to the drawings. 1 and 2 show a substrate processing apparatus 10 preferably used in an embodiment of the present invention. The substrate processing apparatus 10 is configured as an example of a semiconductor manufacturing apparatus used for manufacturing a semiconductor device (device).

<Processing furnace configuration>
As shown in FIGS. 1 and 2, the processing furnace 202 is provided with a heater 207 that is a heating means (heating mechanism, heating system) for heating the wafer (substrate) 200. The heater 207 includes a cylindrical heat insulating member whose upper portion is closed and a plurality of heater wires, and has a unit configuration in which the heater wires are provided on the heat insulating member. 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 has a cylindrical shape with the upper end closed and the lower end opened.

  A manifold 209 made of, for example, stainless steel is attached to the lower end of the reaction tube 203. The manifold 209 is formed in a cylindrical shape, and its lower end opening is airtightly closed by a seal cap 219 that is a lid. O-rings 220 are provided between the reaction tube 203, the manifold 209, and the seal cap 219, respectively. The reaction chamber 203, the manifold 209, and the seal cap 219 form a processing chamber 201. A boat 217 as a substrate holding unit is erected on the seal cap 219 via a boat support base 218.

  A plurality of wafers 200 to be batch-processed are stacked on the boat 217 in a horizontal posture in multiple stages in the tube axis direction. The boat 217 can be moved up and down (in and out) with respect to the reaction tube 203 by the boat elevator 115. A boat rotation mechanism 267 that rotates the boat 217 is provided at the lower end of the boat support 218 in order to improve processing uniformity. By driving the boat rotation mechanism 267, the boat 217 supported by the boat support 218 can be rotated. The heater 207 heats the wafer 200 inserted into the processing chamber 201 to a predetermined temperature.

  In the processing chamber 201, a nozzle 410 (first nozzle 410), a nozzle 420 (second nozzle 420), and a nozzle 430 (third nozzle 430) are provided so as to penetrate the lower part of the reaction tube 203. Yes. The nozzle 410, the nozzle 420, and the nozzle 430 include a gas supply pipe 310 (first gas supply pipe 310), 320 (second gas supply pipe 320), and 330 (third gas supply pipe 330) as gas supply lines. ) Are connected to each other. As described above, the reaction tube 203 is provided with the three nozzles 410, 420, and 430 and the three gas supply tubes 310, 320, and 330. Gas (processing gas, raw material) can be supplied.

  The gas supply pipe 310 is provided with a mass flow controller 312 which is a flow rate control device (flow rate control unit) and a valve 314 which is an on-off valve in order from the upstream side. A nozzle 410 is connected to the tip of the gas supply pipe 310. The nozzle 410 is configured as an L-shaped long nozzle, and its horizontal portion is provided so as to penetrate the side wall of the manifold 209. The vertical portion of the nozzle 410 rises upward along the inner wall of the reaction tube 203 (upward in the loading direction of the wafer 200) in an arc-shaped space formed between the inner wall of the reaction tube 203 and the wafer 200. (That is, rising from one end side to the other end side of the wafer arrangement region). That is, the nozzle 410 is provided on the side of the wafer arrangement area where the wafers 200 are arranged, in a region that horizontally surrounds the wafer arrangement area, along the wafer arrangement area.

  A gas supply hole 410 a for supplying gas is provided on the side surface of the nozzle 410. The gas supply hole 410 a is opened to face the center of the reaction tube 203. A plurality of the gas supply holes 410a are provided from the lower part to the upper part of the reaction tube 203, have the same or inclined opening areas, and are provided at the same opening pitch. A gas supply pipe 310, a mass flow controller 312, a valve 314, and a nozzle 410 constitute a first gas supply system.

  Further, a carrier gas supply pipe 510 for supplying a carrier gas is connected to the gas supply pipe 310. The carrier gas supply pipe 510 is provided with a mass flow controller 512 and a valve 514. A carrier gas supply pipe 510, a mass flow controller 512, and a valve 514 mainly constitute a first carrier gas supply system.

  The gas supply pipe 320 is provided with a mass flow controller 322 as a flow rate control device (flow rate control unit) and a valve 324 as an on-off valve in order from the upstream side. A nozzle 420 is connected to the tip of the gas supply pipe 320. Similarly to the nozzle 410, the nozzle 420 is configured as an L-shaped long nozzle, and a horizontal portion thereof is provided so as to penetrate the side wall of the manifold 209. The vertical part of the nozzle 420 is provided in an arc-shaped space formed between the inner wall of the reaction tube 203 and the wafer 200 so as to rise upward along the inner wall of the reaction tube 203.

  A gas supply hole 420 a for supplying gas is provided on the side surface of the nozzle 420. The gas supply hole 420 a is opened to face the center of the reaction tube 203. A plurality of the gas supply holes 420a are provided from the lower part to the upper part of the reaction tube 203, have the same or inclined opening areas, and are provided at the same opening pitch. The gas supply pipe 320, the mass flow controller 322, the valve 324, and the nozzle 420 mainly constitute a second gas supply system.

  Further, a carrier gas supply pipe 520 for supplying a carrier gas is connected to the gas supply pipe 320. The carrier gas supply pipe 520 is provided with a mass flow controller 522 and a valve 524. The carrier gas supply pipe 520, the mass flow controller 522, and the valve 524 mainly constitute a second carrier gas supply system.

  The gas supply pipe 330 is provided with a mass flow controller 332 that is a flow rate control device (flow rate control unit) and a valve 334 that is an on-off valve in order from the upstream side. A nozzle 430 is connected to the tip of the gas supply pipe 330. Similarly to the nozzle 410, the nozzle 430 is configured as an L-shaped long nozzle, and the horizontal portion thereof is provided so as to penetrate the side wall of the manifold 209. A vertical portion of the nozzle 430 is provided in an arc-shaped space formed between the inner wall of the reaction tube 203 and the wafer 200 so as to rise upward along the inner wall of the reaction tube 203.

  A gas supply hole 430 a for supplying gas is provided on the side surface of the nozzle 430. The gas supply hole 430 a is opened to face the center of the reaction tube 203. A plurality of the gas supply holes 430a are provided from the lower part to the upper part of the reaction tube 203, have the same or inclined opening areas, and are provided at the same opening pitch. The gas supply pipe 330, the mass flow controller 332, the valve 334, and the nozzle 430 mainly constitute a third gas supply system.

  Further, a carrier gas supply pipe 530 for supplying a carrier gas is connected to the gas supply pipe 330. The carrier gas supply pipe 530 is provided with a mass flow controller 532 and a valve 534. A third carrier gas supply system is mainly configured by the carrier gas supply pipe 530, the mass flow controller 532, and the valve 534.

  As described above, the gas supply method according to the present embodiment includes a nozzle 410 arranged in an arc-like vertically long space defined by the inner wall of the reaction tube 203 and the ends of a plurality of stacked wafers 200, The gas is conveyed through 420 and 430, and the gas is jetted into the reaction tube 203 for the first time in the vicinity of the wafer 200 from the gas supply holes 410a, 420b and 430c opened in the nozzles 410, 420 and 430, respectively. The main flow of gas in the reaction tube 203 is set in a direction parallel to the surface of the wafer 200, that is, in a horizontal direction. With such a configuration, there is an effect that the gas can be supplied uniformly to each wafer 200 and the thickness of the thin film formed on each wafer 200 can be made uniform. The residual gas after the reaction flows toward the exhaust port, that is, the direction of the exhaust pipe 231 described later. The direction of the residual gas flow is appropriately specified by the position of the exhaust port and is limited to the vertical direction. It is not a thing.

As an example of the above configuration, from the gas supply pipe 310, for example, titanium tetrachloride (TiCl ₄ ), which is a Ti-containing raw material containing at least a titanium (Ti) element, is a mass flow controller 312 as a raw material gas containing a first metal element. , And supplied into the processing chamber 201 through the valve 314 and the nozzle 410. When using a liquid material that is in a liquid state at normal temperature and pressure, such as TiCl ₄ , the liquid material is vaporized by a vaporization system such as a vaporizer or bubbler and supplied as TiCl ₄ gas that is a Ti-containing gas. It becomes.

From the gas supply pipe 320, as a source gas containing carbon and the second metal element, for example, TMA (trimethylaluminum. (CH ₃ ) ₃ Al) containing at least a carbon (C) element and an aluminum (Al) element. Is supplied into the processing chamber 201 via the mass flow controller 322, the valve 324, and the nozzle 420. In addition, when using the liquid material which is in a liquid state like TMA, a liquid raw material will be vaporized by vaporization systems, such as a vaporizer and a bubbler, and will be supplied as C and Al containing gas.

From the gas supply pipe 330, for example, ammonia (NH ₃ ) is supplied into the processing chamber 201 through the mass flow controller 332, the valve 334, and the nozzle 430 as a source gas containing nitrogen element.

From the carrier gas supply pipes 510, 520 and 530, for example, nitrogen (N ₂ ) gas passes through the mass flow controllers 512, 522 and 532, valves 514, 524 and 534, and nozzles 410, 420 and 430, respectively. To be supplied.

  In addition, for example, when each of the above-described gases is flowed from each gas supply pipe, the metal-containing raw material supply system is configured by the first gas supply system. In addition, a carbon-containing raw material supply system (or carbon and metal-containing raw material supply system) is configured by the second gas supply system. In addition, a nitrogen-containing raw material supply system is configured by the third 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 provided so as to penetrate the side wall of the manifold 209, similarly to the nozzles 410, 420, and 430. The exhaust pipe 231 is provided at a position facing the nozzles 410, 420, and 430 in the manifold 209. With this configuration, the gas supplied from the gas supply holes 410a, 420a, and 430a to the vicinity of the wafer 200 in the processing chamber 201 flows in the horizontal direction, that is, in the direction parallel to the surface of the wafer 200, and then downward. Then, the air flows through the exhaust pipe 231. As described above, the main flow of gas in the processing chamber 201 is a flow in the horizontal direction.

  The exhaust pipe 231 includes, in order from the upstream side, a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201, an APC (Auto Pressure Controller) valve 243, and a vacuum pump as a vacuum exhaust device. 246 is connected. The APC valve 243 is an exhaust valve and functions as a pressure adjustment unit. Further, the exhaust pipe 231 has a trap device that captures reaction by-products and unreacted source gas in the exhaust gas, and a detoxification device that removes corrosive components and toxic components contained in the exhaust gas. May be connected. An exhaust system, that is, an exhaust line, is mainly configured by the exhaust pipe 231, the APC valve 243, and the pressure sensor 245. Note that the vacuum pump 246 may be included in the exhaust system. Furthermore, a trap device or a detoxifying device may be included in the exhaust system.

  Note that the APC valve 243 can open and close the vacuum pump 246 while the vacuum pump 246 is operated, thereby performing vacuum evacuation and stop of the vacuum exhaust in the processing chamber 201. Further, the APC valve 243 can be operated with the vacuum pump 246 operated. Thus, the pressure in the processing chamber 201 can be adjusted by adjusting the valve opening. That is, the exhaust system adjusts the opening degree of the APC valve 243 based on the pressure information detected by the pressure sensor 245 while operating the vacuum pump 246, thereby “actual pressure” in the processing chamber 201. Can be brought close to a predetermined “set pressure”. For example, to change the actual pressure in the processing chamber 201 when there is no change in the flow rate of the gas supplied into the processing chamber 201 or when the gas supply to the processing chamber 201 is stopped, etc. Then, the set pressure in the processing chamber 201 is changed, and the opening degree of the APC valve 243 is changed to an opening degree corresponding to the above set pressure. As a result, the exhaust capacity of the exhaust line is changed, and the actual pressure in the processing chamber 201 gradually (curvedly) approaches the set pressure described above. As described above, the “set pressure” in the processing chamber 201 can be considered to be synonymous with the “target pressure” when the pressure control in the processing chamber 201 is performed. The "pressure" will follow. Further, “changing the set pressure in the processing chamber 201” is substantially synonymous with “changing the opening degree of the APC valve 243 in order to change the exhaust capacity of the exhaust line”. It can be considered as “a command for changing the opening degree of the APC valve 243”.

  A temperature sensor 263 as a temperature detector is installed in the reaction tube 203, and the temperature in the processing chamber 201 is adjusted by adjusting the energization amount to the heater 207 based on the temperature information detected by the temperature sensor 263. It is configured to have a desired temperature distribution. The temperature sensor 263 is configured in an L shape similarly to the nozzles 410, 420, and 430, and is provided along the inner wall of the reaction tube 203.

FIG. 3 shows the controller 121. As shown in FIG. 3, the controller 121 includes a CPU (Central Processing Unit) 121a, a RAM (Random).
Access
(Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to exchange data with the CPU 121a via an internal bus. 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. Note that the process recipe is a combination of functions so that a predetermined result can be obtained by causing the controller 121 to execute each procedure in a substrate processing step to be described later, and functions as a program. Hereinafter, the process recipe, the control program, and the like are collectively referred to as simply a program. When the term “program” is used in this specification, it may include only a process recipe alone, may include only a control program alone, or may include 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 includes the above-described mass flow controllers 312, 322, 332, 512, 522, 532, valves 314, 324, 334, 514, 524, 534, APC valve 243, pressure sensor 245, vacuum pump 246, heater 207. The temperature sensor 263, the rotation mechanism 267, the boat elevator 115 and the like are connected.

  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. Then, according to the read process recipe, the CPU 121a adjusts the flow rates of various gases by the mass flow controllers 312, 322, 332, 512, 522, 532, opens / closes the valves 314, 324, 334, 514, 524, 534, and the APC valve. 243 opening / closing operation and pressure adjustment operation based on the pressure sensor 245 by the APC valve 243, temperature adjustment operation of the heater 207 based on the temperature sensor 263, starting and stopping of the vacuum pump 246, rotation and rotation speed adjustment of the boat 217 by the rotation mechanism 267 It is configured to control the operation, the raising / lowering operation of the boat 217 by the boat elevator 115 and the like.

  The controller 121 is not limited to being configured as a dedicated computer, but 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. 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. Note that 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.

<Configuration of semiconductor device>
Next, a configuration example of a semiconductor device to which the technology according to the present embodiment is applied will be described. Here, a MOSFET is taken as an example of the semiconductor device.

FIG. 4 is an explanatory diagram showing a gate configuration example of a MOSFET. As shown in the figure, the gate of the MOSFET includes a silicon-based insulating film made of silicon oxide (SiO ₂ ) formed on a silicon (Si) substrate, and hafnium oxide (HfO ₂ ) formed on this SiO _2. A high-dielectric film (High-k film) made of and a metal film as a gate electrode made of titanium aluminum carbonitride (TiAlCN) formed on this HfO ₂ are stacked. The feature of this embodiment is the formation of a metal film that constitutes the gate electrode.

<Semiconductor device gate manufacturing process>
Next, an example of a gate manufacturing process of the MOSFET shown in FIG. 4 will be described with reference to FIG. FIG. 5 is a process flow showing an example of a MOSFET gate manufacturing process.

First, the silicon substrate is treated with, for example, a 1% HF aqueous solution to remove the sacrificial oxide film on the Si substrate (“HF treatment” step). Next, silicon oxide (SiO ₂ ) is deposited on the surface of the Si substrate by thermal oxidation (“SiO ₂ formation” step). SiO ₂ is formed as an interface layer at the interface between the Si substrate and HfO ₂ to be formed later.

Next, hafnium oxide (HfO ₂ ) is formed as a high dielectric film on the silicon oxide film (“High-k formation” step). A gate insulating film is composed of SiO ₂ and HfO ₂ . After film formation of HfO ₂ , PDA (Post
Deposition Annealing) is performed (“Post Deposition Annealing” step). This PDA is, for example, a heat treatment furnace (for example, RTP (Rapid
Thermal processing apparatus) is used to house a Si substrate on which HfO ₂ is formed in a processing chamber of the RTP apparatus, and N ₂ gas is supplied into the processing chamber to perform an annealing process. PDA is performed impurity removal during HfO _2, the densification or crystallization of HfO ₂ purposes.

Next, TiAlCN is formed as a metal film on HfO ₂ (“TiAlCN deposition” step). As shown in the figure, in this step, after performing a process of forming a titanium nitride (TiN) layer (first layer) (“TiN formation”) X times (first predetermined number of times), aluminum ( A step of performing a process (“AlCTiN formation”) for forming an AlCTiN layer (second layer) containing Al), carbon (C), titanium (Ti), and nitrogen (N) Y times (second predetermined number of times). Executed. Then, TiAlCN is formed by alternately performing these steps Z times (third predetermined number of times). Details of this processing will be described later.

Next, titanium nitride (TiN) is deposited on the TiAlCN as a Cap film by, for example, PVD (Physical Vapor Deposition) (“Cap TiN deposition” step). Then, using the resist as a mask on the TiN film, patterning using a photolithography technique of the gate electrode (“Gate patterning” process) and pattern etching using a dry etching technique (“Gate etching” process) are performed. Do. Thereafter, the resist is removed (“Resist removal” step). And FGA (Forming) such as hydrogen gas annealing
gas annealing) process ("FGA" process).

<Metal film deposition process>
Next, a film forming process of the metal film constituting the gate electrode described above will be described. The metal film forming step is performed as one step of the semiconductor device (MOSFET) manufacturing process using the processing furnace 202 of the substrate processing apparatus 10 described above.

The preferred sequence of this embodiment is
Performing a process for forming a first layer (eg, TiN) containing a metal element (eg, Ti) and nitrogen (N) on the wafer 200 for a first predetermined number of times;
Performing a process for forming a second layer (eg, AlCTiN) containing the metal element (eg, Ti), nitrogen (N), and carbon (C) on the wafer 200 a second predetermined number of times;
Are alternately performed for a third predetermined number of times to form a metal film (for example, TiAlCN) containing nitrogen (C) and carbon (C) at a predetermined ratio on the wafer 200.

Moreover, the suitable sequence of this embodiment is
A step of alternately supplying a first raw material (eg, TiCl ₄ ) containing a metal element (eg, Ti) and a second raw material (eg, NH ₃ ) containing nitrogen (N) to the wafer 200 a first predetermined number of times. When,
With respect to the wafer 200, a third raw material (for example, TMA) containing carbon (C), a fourth raw material (for example, TiCl ₄ ) containing the metal element (eg, Ti), and a fifth raw material containing nitrogen (N) ( For example, supplying NH ₃ ) alternately for a second predetermined number of times;
Are alternately performed for a third predetermined number of times to form a metal film (for example, TiAlCN) containing nitrogen (N) and carbon (C) at a predetermined ratio on the wafer 200.

  In the present embodiment, the first predetermined number of times, the second predetermined number of times, and the third predetermined number of times are the ratio of nitrogen (N) or carbon (C) included in the metal film (for example, TiAlCN), in other words, For example, it is determined according to the work function of the target gate electrode.

In this specification, when the term “wafer” is used, 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 wafer including a predetermined layer or film formed on the surface). 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.
Note that the term “substrate” in this specification is the same as the term “wafer”. In that case, in the above description, “wafer” is replaced with “substrate”. Good.

  In this specification, the term metal film means a film made of a conductive substance containing a metal atom, and includes a conductive metal nitride film, a conductive metal oxide film, and a conductive film. Metal oxynitride film, conductive metal composite film, conductive metal alloy film, conductive metal silicide film, conductive metal carbide film (metal carbide film), conductive metal carbonitride film (metal carbonitride film) ) Etc. are included. TiAlCN (titanium aluminum carbonitride) is a conductive metal carbonitride film.

  FIG. 6 is a process flow diagram showing an example of a metal film (TiAlCN) deposition process in the process flow shown in FIG. FIG. 7 is a diagram showing gas supply timing in the film forming process shown in FIG. In the following description, the operation of each unit constituting the substrate processing apparatus 10 is controlled by the controller 121.

(Wafer charge and boat load)
When a plurality of wafers 200 are loaded into the boat 217 (wafer charging), as shown in FIG. It is carried in (boat loading). In this state, the seal cap 219 closes the lower end opening of the reaction tube 203 via the O-ring 220.

(Pressure adjustment and temperature adjustment)
The processing chamber 201 is evacuated by a vacuum pump 246 so that a desired pressure (degree of vacuum) is obtained. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 243 is feedback-controlled based on the measured pressure information (pressure adjustment). Note that the vacuum pump 246 keeps being operated at least until the processing on the wafer 200 is completed. Further, the processing chamber 201 is heated by the heater 207 so as to have a desired temperature. At this time, the energization amount to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the processing chamber 201 has a desired temperature distribution (temperature adjustment). Note that the 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, the rotation mechanism 267 starts the rotation of the boat 217 and the wafer 200. Note that 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.

  Subsequently, a process of forming a TiN layer (Step 11 to Step 14) is performed.

<Step 11>
(TiCl ₄ gas supply)
The valve 314 of the gas supply pipe 310 is opened, and TiCl ₄ gas as the first raw material is caused to flow into the gas supply pipe 310. The flow rate of the TiCl ₄ gas that has flowed through the gas supply pipe 310 is adjusted by the mass flow controller 312. The flow-adjusted TiCl ₄ gas is supplied into the processing chamber 201 from the gas supply hole 410 a of the nozzle 410 and is exhausted from the exhaust pipe 231. At this time, TiCl ₄ gas is supplied to the wafer 200. That is, the surface of the wafer 200 is exposed to TiCl ₄ gas. At the same time, the valve 514 is opened, and an inert gas such as N ₂ gas is allowed to flow into the carrier gas supply pipe 510. The flow rate of the N ₂ gas flowing through the carrier gas supply pipe 510 is adjusted by the mass flow controller 512. The N ₂ gas whose flow rate has been adjusted is supplied into the processing chamber 201 together with the TiCl ₄ gas, and is exhausted from the exhaust pipe 231. At this time, in order to prevent the TiCl ₄ gas from entering the nozzles 420 and 430, the valves 524 and 534 are opened, and N ₂ gas is allowed to flow into the carrier gas supply pipe 520 and the carrier gas supply pipe 530. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipe 320, the gas supply pipe 330, the nozzle 420, and the nozzle 430 and is exhausted from the exhaust pipe 231.

At this time, the APC valve 243 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, in the range of 1 to 10,000 Pa. The supply flow rate of TiCl ₄ gas controlled by the mass flow controller 312 is, for example, a flow rate in the range of 10 to 10,000 sccm. The supply flow rate of the N ₂ gas controlled by the mass flow controllers 512, 522, and 532 is set to a flow rate in the range of, for example, 10 to 10,000 sccm. The time for supplying the TiCl ₄ gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, a time in the range of 0.1 to 120 seconds. At this time, the temperature of the heater 207 is set to such a temperature that the temperature of the wafer 200 becomes a temperature within a range of 200 to 500 ° C., for example. By supplying the TiCl ₄ gas, a Ti-containing layer having a thickness of, for example, less than one atomic layer to several atomic layers is formed on the wafer 200.

<Step 12>
(Residual gas removal)
After the Ti-containing layer is formed, the valve 314 of the gas supply pipe 310 is closed and the supply of TiCl ₄ gas is stopped. At this time, the APC valve 243 of the exhaust pipe 231 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and TiCl ₄ after remaining in the processing chamber 201 or contributing to the formation of the Ti-containing layer. The gas is removed from the processing chamber 201. At this time, the valves 514, 524, and 534 are kept open, and the supply of N ₂ gas into the processing chamber 201 is maintained. The N ₂ gas acts as a purge gas, which can enhance the effect of removing the unreacted or residual TiCl ₄ gas that has contributed to the formation of the Ti-containing layer 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. If the amount of gas remaining in the processing chamber 201 is very small, no adverse effect will occur in the subsequent steps. 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), Purge can be performed to the extent that no adverse effect occurs. Thus, 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.

<Step 13>
(NH ₃ gas supply)
After removing the residual gas in the processing chamber 201, the valve 334 of the gas supply pipe 330 is opened, and NH ₃ gas is allowed to flow into the gas supply pipe 330. The flow rate of the NH ₃ gas that has flowed through the gas supply pipe 330 is adjusted by the mass flow controller 332. The NH ₃ gas whose flow rate has been adjusted is supplied into the processing chamber 201 from the gas supply hole 430 a of the nozzle 430. The NH ₃ gas supplied into the processing chamber 201 is activated by heat and then exhausted from the exhaust pipe 231. At this time, NH ₃ gas activated by heat is supplied to the wafer 200. That is, the surface of the wafer 200 is exposed to heat activated NH ₃ gas. At the same time, the valve 534 is opened, and N ₂ gas is caused to flow into the carrier gas supply pipe 530. The flow rate of the N ₂ gas flowing through the carrier gas supply pipe 530 is adjusted by the mass flow controller 532. The N ₂ gas is supplied into the processing chamber 201 together with the NH ₃ gas, and is exhausted from the exhaust pipe 231. At this time, in order to prevent the NH ₃ gas from entering the nozzles 410 and 420, the valves 514 and 524 are opened, and the N ₂ gas is allowed to flow into the carrier gas supply pipes 510 and 520. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipes 310 and 320, the nozzle 410 and the nozzle 420, and is exhausted from the exhaust pipe 231.

When the NH ₃ gas is activated by heat and flows, the APC valve 243 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, in the range of 1 to 10,000 Pa. The supply flow rate of NH ₃ gas controlled by the mass flow controller 332 is, for example, a flow rate in the range of 10 to 50000 sccm. The supply flow rate of the N ₂ gas controlled by the mass flow controllers 512, 522, and 532 is set to a flow rate in the range of, for example, 10 to 10,000 sccm. The time for supplying the NH ₃ gas activated by heat to the wafer 200, that is, the gas supply time (irradiation time) is, for example, a time within the range of 0.1 to 120 seconds. The temperature of the heater 207 at this time is set to a temperature at which the temperature of the wafer 200 becomes a temperature within the range of 200 to 500 ° C., for example, as in step 11.

At this time, the gas flowing into the processing chamber 201 is NH ₃ gas that is thermally activated by increasing the pressure in the processing chamber 201, and this activated NH ₃ gas is converted into the wafer in step 11. Reacts with at least a portion of the Ti-containing layer formed on 200. As a result, the Ti-containing layer is nitrided and modified into a titanium nitride layer (TiN layer).

<Step 14>
(Residual gas removal)
After forming the TiN layer, the valve 334 of the gas supply pipe 330 is closed to stop the supply of NH ₃ gas. At this time, the APC valve 243 of the exhaust pipe 231 is kept open, the inside of the processing chamber 201 is evacuated by the vacuum pump 246, and the NH ₃ gas remaining in the processing chamber 201 and contributing to the formation of the TiN layer remains. And reaction by-products are removed from the processing chamber 201. At this time, the valves 514, 524, and 534 are kept open, and the supply of N ₂ gas into the processing chamber 201 is maintained. The N ₂ gas acts as a purge gas, thereby enhancing the effect of removing NH ₃ gas and reaction by-products remaining in the processing chamber 201 and contributing to formation of the TiN layer from the processing chamber 201. Can do.

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 steps. 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), Purge can be performed to the extent that no adverse effect occurs. Thus, 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.

The above-described processing from step 11 to step 14 is executed X times (first predetermined number of times) set in advance. That is, the process from step 11 to step 14 is set as one set, and these processes are executed for X sets. In this manner, TiN ₄ gas supply and NH ₃ gas supply are alternately performed X times to form a TiN layer (first layer) having a predetermined thickness (for example, 0.03 to 20 nm).

  After performing the above-described processing from step 11 to step 14 X times (X set), the following steps (step 15 to step 20) for forming an AlCTiN layer are performed.

<Step 15>
(TMA gas supply)
The valve 324 of the gas supply pipe 320 is opened, and TMA (trimethylaluminum. (CH ₃ ) ₃ Al) gas is allowed to flow through the gas supply pipe 320. The flow rate of the TMA gas flowing through the gas supply pipe 320 is adjusted by the mass flow controller 322. The flow-adjusted TMA gas is supplied from the gas supply hole 420 a of the nozzle 420 into the processing chamber 201 and is exhausted from the exhaust pipe 231. At this time, TMA gas is supplied to the wafer 200. That is, the surface of the wafer 200 is exposed to TMA gas. At the same time, the valve 524 is opened, and N ₂ gas is caused to flow into the carrier gas supply pipe 520. The N ₂ gas that has flowed through the carrier gas supply pipe 520 is adjusted in flow rate by the mass flow controller 522. The N ₂ gas whose flow rate has been adjusted is supplied into the processing chamber 201 together with the TMA gas, and is exhausted from the exhaust pipe 231. At this time, in order to prevent the TMA gas from entering the nozzles 410 and 430, the valves 514 and 534 are opened, and N ₂ gas is allowed to flow into the carrier gas supply pipe 510 and the carrier gas supply pipe 530. The N ₂ gas is supplied into the processing chamber 201 through the gas supply pipe 310, the gas supply pipe 330, the nozzle 410, and the nozzle 430 and is exhausted from the exhaust pipe 231.

At this time, the APC valve 243 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, a pressure in the range of 1 to 10,000 Pa as in Step 11. The supply flow rate of TMA gas controlled by the mass flow controller 322 is, for example, a flow rate in the range of 10 to 10,000 sccm. The supply flow rate of the N ₂ gas controlled by the mass flow controllers 512, 522, and 532 is set to a flow rate in the range of, for example, 10 to 10,000 sccm. The time for supplying the TMA gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, a time within the range of 0.1 to 120 seconds. The temperature of the heater 207 at this time is set to a temperature at which the temperature of the wafer 200 becomes a temperature within the range of 200 to 500 ° C., for example, as in step 11. By supplying the TMA gas, a layer containing carbon (C) and aluminum (Al) is formed on the TiN layer. The layer containing C and Al is formed to a thickness of, for example, less than one atomic layer to several atomic layers.

<Step 16>
(Residual gas removal)
Thereafter, the valve 324 of the gas supply pipe 320 is closed to stop the supply of TMA gas. At this time, the APC valve 243 of the exhaust pipe 231 is kept open, and the inside of the processing chamber 201 is evacuated by the vacuum pump 246 to form an unreacted or residual layer containing C and Al remaining in the processing chamber 201. The TMA gas after the contribution is removed from the processing chamber 201. At this time, the valves 510, 520, and 530 remain open, and the supply of N ₂ gas into the processing chamber 201 is maintained. The N ₂ gas acts as a purge gas, thereby increasing the effect of removing the TMA gas remaining in the processing chamber 201 or contributing to the formation of the layer containing C and Al from the processing chamber 201. be able to.

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 steps. 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), Purge can be performed to the extent that no adverse effect occurs. Thus, 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.

<Step 17>
(TiCl ₄ gas supply)
Next, TiCl ₄ gas is supplied into the processing chamber 201 by the same processing as in step 11. At this time, the APC valve 243 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, in the range of 1 to 10,000 Pa. The supply flow rate of TiCl ₄ gas controlled by the mass flow controller 312 is, for example, a flow rate in the range of 10 to 10,000 sccm. The supply flow rate of the N ₂ gas controlled by the mass flow controllers 512, 522, and 532 is set to a flow rate in the range of, for example, 10 to 10,000 sccm. The time for supplying the TiCl ₄ gas to the wafer 200, that is, the gas supply time (irradiation time) is, for example, a time in the range of 0.1 to 120 seconds. At this time, the temperature of the heater 207 is set to such a temperature that the temperature of the wafer 200 becomes a temperature within a range of 200 to 500 ° C., for example. TiCl ₄ gas supplied into the processing chamber 201 reacts with at least a part of the layer containing C and Al. Thereby, the layer containing C and Al is modified into a layer containing carbon (C), aluminum (Al), and titanium (Ti).

<Step 18>
(Residual gas removal)
Subsequently, the TiCl ₄ gas and by-products that have remained in the processing chamber 201 or contributed to the formation of the above-described layer containing C, Al, and Ti are removed from the processing chamber 201 by the same processing as in Step 12 and the like. Eliminate from within.

<Step 19>
(NH ₃ gas supply)
Next, NH ₃ gas is supplied into the processing chamber 201 by the same processing as in Step 13. At this time, the APC valve 243 is appropriately adjusted so that the pressure in the processing chamber 201 is, for example, in the range of 1 to 10,000 Pa. The supply flow rate of NH ₃ gas controlled by the mass flow controller 332 is, for example, a flow rate in the range of 10 to 50000 sccm. The supply flow rate of the N ₂ gas controlled by the mass flow controllers 512, 522, and 532 is set to a flow rate in the range of, for example, 10 to 10,000 sccm. The time for supplying the NH ₃ gas activated by heat to the wafer 200, that is, the gas supply time (irradiation time) is, for example, a time within the range of 0.1 to 120 seconds. The temperature of the heater 207 at this time is set to a temperature at which the temperature of the wafer 200 becomes a temperature within the range of 200 to 500 ° C., for example, as in step 11. The NH ₃ gas supplied into the processing chamber 201 reacts with at least a part of the layer containing C, Al, and Ti. Thereby, the layer containing C, Al, and Ti is modified into the AlCTiN-containing layer described above.

<Step 20>
(Residual gas removal)
Subsequently, TiCl ₄ gas and by-products that have contributed to the formation of the unreacted or AlCTiN-containing layer remaining in the processing chamber 201 are removed from the processing chamber 201 by the same processing as in step 14 and the like.

The above-described processing from step 15 to step 20 is executed Y times (second predetermined number of times) set in advance. That is, the process from step 15 to step 20 is set as one set, and these processes are executed for Y sets. As described above, by alternately performing TMA gas supply, TiCl ₄ gas supply, and NH ₃ gas supply Y times, an AlCTiN layer (second layer) having a predetermined thickness (for example, 0.1 to 20 nm). Form.

  The TiAlCN film as the gate electrode is composed of a laminate of the TiN layer and the AlCTiN layer described above. By repeating the step of forming the TiN layer and the step of forming the AlCTiN layer alternately Z times (third predetermined number of times), a predetermined thickness (for example, 1.0 to 20 nm) is obtained. A TiAlCN film is formed. The TiAlCN film can also be referred to as an AlC-doped TiN film (AlC-added TiN film) obtained by doping Al and C into a TiN film.

  Here, the number of times of performing the processing from Step 11 to Step 14 for forming the TiN layer (the above-mentioned X or the multiplication value of X and Z) and the number of times of performing the processing from Step 15 to Step 20 for forming the AlCTiN layer. The ratio of each element contained in the TiAlCN film can be adjusted by (the above-mentioned Y or a multiplication value of Y and Z). In other words, the work function of the gate electrode formed of the TiAlCN film can be tuned (adjusted or modulated) by adjusting the number of times of each process. In other words, the values of X, Y, and Z are determined according to the ratio of nitrogen or carbon (or the ratio of nitrogen, carbon, titanium, and aluminum) included in the TiAlCN film. X and Y are integers of 0 or more, and Z is an integer of 1 or more. X and / or Y is preferably an integer of 1 or more.

  Among the elements contained in the TiAlCN film, the work functions of the two metal elements (Ti and Al) are both about 4.3 eV. The inventors of the present application have obtained the knowledge that the work function can be increased or decreased based on about 4.3 eV which is the work function of Ti and Al by adjusting the ratio of C and N in the TiAlCN film. Yes. Specifically, when the proportion of C is increased, a work function lower than 4.3 eV can be obtained, and when the proportion of N is increased, a work function higher than 4.3 eV can be obtained. Therefore, a metal film having a desired work function can be formed by determining each value of X, Y, and Z according to the ratio of N or C included in the TiAlCN film.

(Purge and return to atmospheric pressure)
When a film forming process for forming a TiAlCN film having a predetermined thickness is performed, an inert gas such as N ₂ is supplied into the processing chamber 201 and is exhausted from the exhaust pipe 231, so that the inside of the processing chamber 201 is incomplete. Purge with active gas (gas 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, the lower end of the reaction tube 203 is opened, 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. Unload (boat unload). Thereafter, the processed wafer 200 is taken out from the boat 217.

(Other embodiments of the present invention)
In the above description, the TiN layer, that is, the metal nitride film is formed as the first layer constituting the TiAlCN film, but a metal carbide film may be formed instead of the metal nitride film.

For example, a TiAlCN film having a metal carbide film as the first layer can be formed by the following sequence.
Performing a process for forming a first layer (for example, TiC) containing a metal element (for example, Ti) and carbon (C) on the wafer 200 for a first predetermined number of times;
Performing a process for forming a second layer (eg, AlCTiN) containing the metal element (eg, Ti), nitrogen (N), and carbon (C) on the wafer 200 a second predetermined number of times;
Are alternately performed for a third predetermined number of times to form a metal film (for example, TiAlCN) containing nitrogen (C) and carbon (C) at a predetermined ratio on the wafer 200.

Moreover, the suitable sequence of this embodiment is
A first raw material (for example, TiCl ₄ ) containing a metal element (for example, Ti) and a second raw material (for example, Hf [C ₅ H ₄ (CH ₃ )] ₂ (CH ₃ ) containing carbon (C) with respect to the wafer 200. ) ₂ ) and alternately supplying the first predetermined number of times;
With respect to the wafer 200, a third raw material (for example, TMA) containing carbon (C), a fourth raw material (for example, TiCl ₄ ) containing the metal element (eg, Ti), and a fifth raw material containing nitrogen (N) ( For example, supplying NH ₃ ) alternately for a second predetermined number of times;
Are alternately performed for a third predetermined number of times to form a metal film (for example, TiAlCN) containing nitrogen (N) and carbon (C) at a predetermined ratio on the wafer 200.
In this sequence example, a gas supply system for supplying Hf [C ₅ H ₄ (CH ₃ )] ₂ (CH ₃ ) ₂ to the processing chamber 201 is added to the substrate processing apparatus 10.

In the above-described embodiment, an example in which a TiAlCN film is formed as a metal film constituting the gate electrode is described. However, the metal film is not limited to this, and tantalum (Ta), cobalt (Co), tungsten (W ), Molybdenum (Mo), ruthenium (Ru), yttrium (Y), lanthanum (La), zirconium (Zr), hafnium (Hf), etc., a metal carbide film, metal nitride film or metal carbonitride containing one or more metal elements A film or a silicide film obtained by adding silicon (Si) to these films may be formed. At that time, tantalum chloride (TaCl ₄ ) or the like can be used as the Ta-containing raw material, and Co amd [(tBu) NC (CH ₃ ) N (tBu) ₂ Co] or the like can be used as the Co-containing raw material. Tungsten fluoride (WF ₆ ) or the like can be used as the W-containing raw material, molybdenum chloride (MoCl ₃ or MoCl ₅ ) or the like can be used as the Mo-containing raw material, and 2,4- Dimethylpentadienyl (ethylcyclopentadienyl) ruthenium ((Ru (EtCp) (C ₇ H ₁₁ )) or the like can be used, and trisethylcyclopentadienyl yttrium (Y (C ₂ H ₅ C ₅ H _{4) 3)} or the like can be used, as the La-containing material tris isopropylcyclopentadienyl Lanthanum _{(La (i-C 3 H} 7 C 5 H 4) 3) or the like can be used, as the Zr-containing raw material tetrakis ethylmethylamino zirconium _{(Zr (N (CH 3 (} C 2 H 5)) 4) Tetrakisethylmethylaminohafnium (Hf (N (CH ₃ (C ₂ H ₅ )) ₄ ) or the like can be used, and tetrachlorosilane (SiCl ₄ ), hexachlorodisilane (Si Si ₂ Cl ₆ ), dichlorosilane (SiH ₂ Cl ₂ ), trisdimethylaminosilane (SiH (N (CH ₃ ) ₂ ) ₃ ), _binary butylaminosilane (H ₂ Si (HNC (CH ₃ ) ₂ ) ₂ ), etc. Can be used.

In the above-described embodiment, an example in which TiCl ₄ gas is used as the Ti-containing raw material has been described. However, the present invention is not limited thereto, and tetrakisdimethylaminotitanium (TDMAT, Ti [N (CH ₃ ) ₂ ] ₄ ), tetrakis A titanium (Ti) -containing gas other than a halogen compound such as diethylaminotitanium (TDEAT, Ti [N (CH ₂ CH ₃ ) ₂ ] ₄ ) may be used.

In the above-described embodiment, TMA gas or Hf [C ₅ H ₄ (CH ₃ )] ₂ (CH ₃ ) ₂ is given as an example of the carbon-containing raw material, but not limited thereto, Zr [C ₅ H ₄ (CH ₃ )] ₂ (CH ₃ ) ₂ gas, ethylene (C ₂ H ₄ ), propylene (C ₃ H ₆ ), butene (C ₄ H ₈ ), pentene (C ₅ H ₁₀ ), hexene (C ₆ H ₁₂ ), heptene (C ₇ H ₁₄ ), octene (C ₈ H ₁₆ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), pentane (C ₅ H ₁₂₎ ), Hexane (C ₆ H ₁₄ ), heptane (C ₇ H ₁₆ ), octane (C ₈ H ₁₈ ) and the like may be used.

In the above-described embodiment, an example in which NH ₃ gas is used as the nitrogen-containing raw material has been described. However, the present invention is not limited to this, but diazene (N ₂ H ₂ ) gas, hydrazine (N ₂ H ₄ ) gas, N ₃ H ₈ gas, nitrogen (N ₂ ), nitrous oxide (N ₂ O), monomethyl hydrazine (CH ₆ N ₂ ), dimethyl hydrazine (C ₂ H ₈ N ₂ ), or the like may be used. Further, as the inert gas, a rare gas such as Ar gas, He gas, Ne gas, Xe gas, etc. may be used in addition to N ₂ gas.

  In the above-described embodiment, an example in which one metal element is included as the first layer has been described. However, the first layer may include two or more metal elements (for example, Ti and Al). In the above-described embodiment, the same metal element is included in the first layer and the second layer, but this is not always necessary. For example, in the above-described embodiment, Ti may be included in the first layer and Ti may not be included in the second layer.

  In the above-described embodiment, when the ratio of C contained in the metal film is set to 0, a TiAlN film or a TiN film can be formed instead of the TiAlCN film. Further, when the ratio of N contained in the metal film is set to 0, a TiAlC film or a TiC film can be formed instead of the TiAlCN film.

  In the above-described embodiment, when the TiAlCN film is formed, the TiN layer and the AlCTiN layer are formed in this order, but the AlCTiN layer and the TiN layer may be formed in this order. Similarly, instead of the TiC layer and the AlCTiN layer in this order, the AlCTiN layer and the TiC layer may be formed in this order.

  Moreover, the above-mentioned embodiment, each modification, each application example, etc. can be used in combination as appropriate. Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  In the above-described embodiment, an example in which film formation is performed using a substrate processing apparatus which is a batch type vertical apparatus that processes a plurality of substrates at a time has been described. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention can also be suitably applied when a film is formed using a single-wafer type substrate processing apparatus that processes one or several substrates. 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. However, the present invention is not limited to this, and a cold wall type processing furnace is provided. The present invention can also be suitably applied when forming a thin film using a substrate processing apparatus.

  The present invention can also be realized by changing a process recipe of an existing substrate processing apparatus, for example. When changing a process recipe, the process recipe according to the present invention is installed in an existing substrate processing apparatus via a telecommunication line or a recording medium recording the process recipe, or input / output of the existing substrate processing apparatus It is also possible to operate the apparatus and change the process recipe itself to the process recipe according to the present invention.

  Examples will be described below, but the present invention is not limited to these examples. In each of the following examples, a TiAlCN film was formed on the wafer 200 (specifically, on the HfO film which is a high dielectric film) by the sequence shown in FIG. 6 and FIG.

  In Example 1, X, Y, and Z described above were set to 6, 1 and 36, respectively. That is, in Example 1, the process of forming the TiN layer 6 times (X = 6) and the process of forming the AlCTiN layer 1 time (Y = 1) are alternately performed 36 times (Z = 36) A TiAlCN film was formed by repeating the process.

Specifically, in Example 1, a TiN ₄ gas and NH ₃ gas are alternately supplied six times to form a TiN layer, and TMA gas, TiCl ₄ gas, and NH ₃ gas are once applied. The TiAlCN film was formed by alternately repeating the step of supplying and forming the AlCTiN layer 36 times. The processing conditions in each step at that time were set as follows.

<TiN layer formation>
(Step 11)
Processing room temperature: 350 ° C
Processing chamber pressure: 45Pa
TiCl ₄ gas supply rate: 1.16 g / min
TiCl ₄ gas irradiation time: 5 seconds (step 13)
Processing room temperature: 350 ° C
Processing chamber pressure: 65 Pa
NH ₃ gas supply flow rate: 7500sccm
NH ₃ gas irradiation time: 15 seconds

<AlCTiN layer formation>
(Step 15)
Processing room temperature: 350 ° C
Processing chamber pressure: 65 Pa
TMA gas supply amount: 0.6 g / min
TMA gas irradiation time: 6 seconds (Step 17)
Processing room temperature: 350 ° C
Processing chamber pressure: 45Pa
TiCl ₄ gas supply rate: 1.16 g / min
TiCl ₄ gas irradiation time: 5 seconds (step 19)
Processing room temperature: 350 ° C
Processing chamber pressure: 65 Pa
NH ₃ gas supply flow rate: 7500sccm
NH ₃ gas irradiation time: 15 seconds

  The thickness of the TiAlCN film formed by the above treatment was 10 nm, and a 30 nm TiN film was formed as a cap layer on the TiAlCN film.

  In Example 2, X, Y, and Z described above were set to 3, 1, and 52, respectively. That is, in Example 2, the process of forming the TiN layer three times (X = 3) and the process of forming the AlCTiN layer once (Y = 1) are alternately performed 52 times (Z = 52) A TiAlCN film was formed by repeating the process.

Specifically, in Example 2, TiTi ₄ gas and NH ₃ gas are alternately supplied three times to form a TiN layer, and TMA gas, TiCl ₄ gas, and NH ₃ gas are once applied. The step of supplying and forming the AlCTiN layer was repeated 52 times alternately to form a TiAlCN film. The processing conditions in each step at that time are the same as those in the first embodiment. The thickness of the TiAlCN film formed in Example 2 is 10 nm.

  In Example 3, X, Y, and Z described above were set to 1, 1 and 78, respectively. That is, in Example 3, the process of forming the TiN layer once (X = 1) and the process of forming the AlCTiN layer once (Y = 1) are alternately performed 78 times (Z = 78) A TiAlCN film was formed by repeating the process.

Specifically, in Example 3, a process of forming a TiN layer by supplying TiCl ₄ gas and NH ₃ gas once, and supplying TMA gas, TiCl ₄ gas, and NH ₃ gas once. Then, the process of forming the AlCTiN layer was alternately repeated 78 times to form a TiAlCN film. The processing conditions in each step at that time are the same as those in the first embodiment. The thickness of the TiAlCN film formed in Example 3 is 10 nm.

  In Example 4, X, Y, and Z described above were set to 0, 1, and 100, respectively. That is, in Example 4, the process of forming the TiN layer is not performed (X = 0), and the process of forming the AlCTiN layer once (Y = 1) is repeated 100 times (Z = 100). Then, a TiAlCN film was formed.

Specifically, in Example 4, the TiAlCN film was formed by repeating the process of supplying the TMA gas, the TiCl ₄ gas, and the NH ₃ gas once to form the AlCTiN layer 100 times. The processing conditions in each step at that time are the same as those in the first embodiment. The thickness of the TiAlCN film formed in Example 4 is 10 nm.

  In Example 5, X, Y, and Z described above were set to 1,0, 340, respectively. That is, in Example 5, the process of forming the AlCTiN layer is not performed (Y = 0), and the process of forming the TiN layer once (X = 1) is repeated 340 times (Z = 340). Then, a TiN film was formed.

Specifically, in Example 5, the TiN film was formed by repeating the process of supplying the TiCl ₄ gas and the NH ₃ gas once to form the TiN layer 340 times. The processing conditions in each step at that time are the same as those in the first embodiment. Further, the thickness of the TiN film formed in Example 5 is 10 nm.

  FIG. 8 shows the relationship between EOT (equivalent oxide film thickness) and Vfb (flat band voltage) for each of the metal films (TiAlCN film or TiN film) formed in Examples 1-5. As shown in the figure, it can be seen that the Vfb shifts in the negative direction as the C ratio (concentration) is higher (N ratio (concentration) is lower). When Vfb shifts in the negative direction, the work function decreases.

FIG. 9 shows the relationship between the ratio of C and N and the effective work function eWF for each of the metal films (TiAlCN film or TiN film) formed in Examples 1 to 5. 10A shows the work function with respect to the ratio of C for each of the metal films formed in Examples 1 to 5, and FIG. 10B shows the metal formed in Examples 1 to 5. For each of the films, the work function for the percentage of N is shown. In each of the above-described embodiments, the work function of the metal film itself is tuned by adjusting each value of X, Y, and Z. However, in FIGS. 9 and 10, the film was formed in each embodiment. The effective work function eWF of the gate electrode containing a metal film is shown. This effective work function eWF is a value calculated from the above-mentioned Vfb, and is a value including the dipole at the HfO ₂ / SiO ₂ interface.

  As shown in FIGS. 9 and 10, the effective work function eWF decreases as the proportion of C contained in the TiAlCN film (or TiN film) increases, and the effective work function eWF increases as the proportion of N increases. The dipole is determined according to the type of the high dielectric film, and is constant in each embodiment. Therefore, it can be said that the work function of the TiAlCN film decreases as the proportion of C contained in the TiAlCN film increases, and the work function of the TiAlCN film increases as the proportion of N increases.

In a High-k film such as an HfO ₂ film, oxygen in the High-k film diffuses and escapes from the High-k film due to the heat treatment in the process, so that an interface dipole is formed between the High-k film and the interface layer. As a result, the effective work function is increased. As shown in FIG. 9, the work function of the TiN film that is the metal film according to the fifth embodiment is about 5.0 eV including the dipole, whereas the work function of the TiAlCN film that is the metal film according to the first to fourth embodiments. The work function is 4.52 to 4.68 eV. In consideration of the influence of _dipole eΔ _dipole (0.31 eV, quoted from Y. Kamimura et al., IEDM (2007), PP. 341-344), the work function of the TiAlCN film is 4.21-4. It was confirmed that the work function can be tuned based on the above-described work function of Ti and Al (about 4.3 eV) by controlling the ratio of C and / or N contained therein. .

  Further, the work function of the TiAlN film containing Ti as the metal element and not containing C and the TiN film is about 4.6 to 4.7 eV, and the work function of the TiAlC film containing Ti as the metal element and not containing N is about 4 The inventors have confirmed that the voltage is 1 V. That is, the TiAlCN film containing Ti as a metal element and further containing C and N controls the work function of the TiAlC film and the work function of the TiAlN film (or TiN film) by controlling the ratio of C and N. It can be tuned to the desired value between functions.

  Thus, by controlling the ratio of C and / or N, a metal capable of adjusting Vth (threshold voltage, threshold voltage), that is, a TiAlCN film as a metal film whose work function can be tuned is provided. It was confirmed by experiments. Therefore, according to the present invention, it is possible to adjust the work function with one metal film having the same elemental composition even when different work function values are required depending on the application.

  The effective work function can also be tuned by a φ dipole or φFLP (Fermi-Level Pinning), but it is desirable to tune the work function of the metal film itself constituting the gate electrode for the following reason.

The value of the φ dipole is controlled by the film type of the high dielectric film or by diffusing Al, La, or the like from the gate electrode into the high dielectric film. However, when controlling by the type of the high dielectric film, the dipole value shifts in the same direction in both NMOS and PMOS (a dipole that shifts in the negative direction in NMOS and in the positive direction in PMOS is required). Therefore, it is necessary to make a high dielectric film separately for NMOS and PMOS, which complicates the process. Further, when Al, La, or the like is diffused and controlled from the gate electrode, heat treatment at about 1000 ° C. is necessary. However, when a high dielectric film is used, it is generally a gate last process, and the heat treatment at about 1000 ° C. is performed before the formation of the gate stack (electrode / high dielectric film / SiO ₂ / Si substrate). This heat treatment is a process for activating the source / drain. Therefore, in the gate last process, it is desirable that a heat treatment at about 1000 ° C. is unnecessary after the gate stack. Furthermore, in order to increase the tuning amount of the effective work function, it is necessary to increase the φ dipole. However, if the φ dipole is increased, the mobility (speed of movement of electrons and holes) may be reduced. Further, the value of φFLP can be controlled by adding Si to the electrode, but in this case, the resistance of the electrode may be increased. Therefore, it is desirable to tune the work function of the metal film itself.

  Hereinafter, desirable modes of the present invention will be additionally described.

[Appendix 1]
According to one aspect of the invention,
Performing a process for forming a first layer containing a metal element and nitrogen or carbon for a first predetermined number of times;
Performing a process for forming a second layer containing the metal element, nitrogen and carbon for a second predetermined number of times;
By alternately performing the third predetermined number of times, a method of manufacturing a semiconductor device including a step of forming a metal film containing nitrogen and carbon at a predetermined ratio on a substrate is provided.

[Appendix 2]
According to another aspect of the invention,
Supplying a first raw material containing a metal element and a second raw material containing nitrogen or carbon to the substrate alternately for a first predetermined number of times;
Supplying a third raw material containing carbon, a fourth raw material containing the metal element, and a fifth raw material containing nitrogen alternately to the substrate a second predetermined number of times;
By alternately performing the third predetermined number of times, a method of manufacturing a semiconductor device including a step of forming a metal film containing nitrogen and carbon at a predetermined ratio on a substrate is provided.

[Appendix 3]
In Supplementary Note 1 or 2, the first predetermined number of times, the second predetermined number of times, and the third predetermined number of times are determined according to a ratio of nitrogen or carbon included in the metal film.

[Appendix 4]
In Supplementary Note 1, the second layer includes a second metal element different from the metal element.

[Appendix 5]
In Supplementary Note 2, the third raw material includes a second metal element different from the metal element.

[Appendix 6]
In any one of appendices 1 to 5, the metal film is formed on a high dielectric film formed on the substrate.

[Appendix 7]
In any one of appendices 1 to 6, the metal element includes at least one element selected from the group consisting of titanium, tantalum, hafnium, zirconium, molybdenum, and tungsten.

[Appendix 8]
In Additional Statement 4 or 5, the second metal element includes aluminum.

[Appendix 9]
In Supplementary Note 2, the first raw material and the fourth raw material include TiCl ₄ .

[Appendix 10]
In Supplementary Note 5, the third raw material includes TMA (trimethylaluminum).

[Appendix 11]
In Additional Notes 1 to 10, the metal element is titanium, and the work function of the metal film is a value between the work function of TiN or TiAlN and the work function of TiAlC.

[Appendix 12]
In Additional Statement 4 or 5, the metal element is titanium, the second metal element is aluminum, and the work function of the metal film is a value between the work function of TiN or TiAlN and the work function of TiAlC.

[Appendix 13]
According to another aspect of the invention,
Performing a process for forming a first layer containing a metal element and nitrogen or carbon for a first predetermined number of times;
Performing a second predetermined treatment for forming a second layer containing the metal element, nitrogen and carbon;
By alternately performing the third predetermined number of times, a substrate processing method including a step of forming a metal film containing nitrogen and carbon in a predetermined ratio on the substrate is provided.

[Appendix 14]
According to another aspect of the invention,
Supplying a first raw material containing a metal element and a second raw material containing nitrogen or carbon to the substrate alternately for a first predetermined number of times;
Supplying a third raw material containing carbon, a fourth raw material containing the metal element, and a fifth raw material containing nitrogen alternately to the substrate a second predetermined number of times;
By alternately performing the third predetermined number of times, there is provided a substrate processing method including a step of forming a metal film containing nitrogen and carbon at a predetermined ratio on the substrate.

[Appendix 15]
In Supplementary Note 13 or 14, the first predetermined number of times, the second predetermined number of times, and the third predetermined number of times are determined according to a ratio of nitrogen or carbon included in the metal film.

[Appendix 16]
According to another aspect of the invention,
A processing chamber for accommodating the substrate;
A metal-containing raw material supply system for supplying a metal-containing raw material containing a metal element to the substrate connected to the processing chamber and housed in the processing chamber;
A nitrogen-containing material supply system for supplying a nitrogen-containing material containing nitrogen to the substrate connected to the processing chamber and housed in the processing chamber;
A carbon-containing raw material supply system for supplying a carbon-containing raw material containing carbon to the substrate connected to the processing chamber and housed in the processing chamber;
Connected to the metal-containing material supply system, the nitrogen-containing material supply system, and the carbon-containing material supply system, and with respect to the substrate housed in the processing chamber, the metal-containing material and the nitrogen-containing material or the A process of alternately supplying a carbon-containing raw material for a first predetermined number of times and a process of supplying the metal-containing raw material, the nitrogen-containing raw material, and the carbon-containing raw material alternately for a second predetermined number of times Performing a predetermined number of times to form a metal film containing nitrogen and carbon in a predetermined ratio on the substrate, the metal-containing raw material supply system, the nitrogen-containing raw material supply system, and the carbon-containing raw material supply. A control unit configured to control and execute the system;
A substrate processing apparatus is provided.

[Appendix 17]
In Supplementary Note 16, the first predetermined number of times, the second predetermined number of times, and the third predetermined number of times are determined according to a ratio of the nitrogen or the carbon included in the metal film.

[Appendix 18]
According to another aspect of the invention,
A procedure of performing a first predetermined number of times to form a first layer containing a metal element and nitrogen or carbon;
A step of performing a process for forming a second layer containing the metal element, nitrogen and carbon for a second predetermined time;
By alternately performing the third predetermined number of times, there is provided a program for causing a computer to execute a procedure for forming a metal film containing nitrogen and carbon at a predetermined ratio on a substrate.

[Appendix 19]
In Supplementary Note 18, the first predetermined number of times, the second predetermined number of times, and the third predetermined number of times are determined according to a ratio of nitrogen or carbon included in the metal film.

[Appendix 20]
According to another aspect of the invention,
A procedure of performing a first predetermined number of times to form a first layer containing a metal element and nitrogen or carbon;
A step of performing a process for forming a second layer containing the metal element, the nitrogen, and the carbon for a second predetermined time;
By alternately performing the third predetermined number of times, there is provided a computer-readable recording medium on which a program for causing a computer to execute a procedure for forming a metal film containing nitrogen and carbon at a predetermined ratio on a substrate is provided. The

[Appendix 21]
In Supplementary Note 20, the first predetermined number of times, the second predetermined number of times, and the third predetermined number of times are determined according to a ratio of nitrogen or carbon included in the metal film.

  As described above, the present invention can be used for, for example, a method for manufacturing a semiconductor device, a substrate processing apparatus for processing a substrate such as a semiconductor wafer or a glass substrate, and the like.

DESCRIPTION OF SYMBOLS 10 ... Substrate processing apparatus 200 ... Wafer 201 ... Processing chamber 202 ... Processing furnace

Claims (8)

(A) supplying a first raw material containing titanium element and a second raw material containing nitrogen alternately x times to the substrate to form a titanium nitride layer on the substrate;
(B) An aluminum titanium carbonitride layer is provided on the substrate by supplying a third raw material containing an aluminum element and carbon, the first raw material, and the second raw material alternately y times to the substrate. Forming a step;
(C) performing (A) and (B) alternately z times to form a titanium aluminum carbonitride film on the substrate;
Have
The x, y, and z are integers of 1 or more, respectively, and the ratio of titanium, aluminum, carbon, and nitrogen contained in the titanium aluminum carbonitride film is adjusted by adjusting the values of the x, y, and z. A method for manufacturing a semiconductor device, wherein the work function of the titanium aluminum carbonitride film is modulated to a value in the range of 4.52 to 4.68 eV.   2. The method of manufacturing a semiconductor device according to claim 1, wherein when the values of x, y, and z are adjusted, a multiplication value of x and z and a multiplication value of y and z are adjusted.   The method for manufacturing a semiconductor device according to claim 1, wherein a ratio of carbon to nitrogen (carbon / nitrogen) contained in the titanium aluminum carbonitride film is set to ¼ or less.   The method for manufacturing a semiconductor device according to claim 1, wherein a ratio of carbon to nitrogen (carbon / nitrogen) contained in the titanium aluminum carbonitride film is 1/6 or less.   The method of manufacturing a semiconductor device according to claim 1, wherein a ratio of carbon and nitrogen (carbon / nitrogen) contained in the titanium aluminum carbonitride film is 1/10 or less.   In (A), the value of x is adjusted to form the titanium nitride layer to a thickness of 0.03 to 20 nm. In (B), the value of y is adjusted to adjust the aluminum titanium carbonitride layer. 2 is formed to have a thickness of 0.1 to 20 nm, and in (C), the value of z is adjusted to form the titanium aluminum carbonitride film to have a thickness of 1.0 to 200 nm. The manufacturing method of the semiconductor device of description. A processing chamber for accommodating the substrate;
A first raw material supply system for supplying a first raw material containing titanium element to the processing chamber;
A second raw material supply system for supplying a second raw material containing nitrogen to the processing chamber;
A third raw material supply system for supplying a third raw material containing aluminum element and carbon to the processing chamber;
Controlling the first raw material supply system, the second raw material supply system, and the third raw material supply system, and (A) the first raw material, the second raw material, and the substrate stored in the processing chamber; Alternately supplying x times to form a titanium nitride layer on the substrate; and (B) alternating the third material, the first material, and the second material with respect to the substrate. Supplying y times to form an aluminum titanium carbonitride layer on the substrate;
(C) (A) and (B) are alternately performed z times to form a titanium aluminum carbonitride film on the substrate;
Have
The x, y, and z are integers of 1 or more, respectively, and the ratio of titanium, aluminum, carbon, and nitrogen contained in the titanium aluminum carbonitride film is adjusted by adjusting the values of the x, y, and z. A control unit configured to modulate the work function of the titanium aluminum carbonitride film to a value in the range of 4.52 to 4.68 eV;
A substrate processing apparatus. (A) A first raw material containing titanium element and a second raw material containing nitrogen are alternately supplied x times to the substrate in the processing chamber of the substrate processing apparatus to form a titanium nitride layer on the substrate. Procedure and
(B) An aluminum titanium carbonitride layer is provided on the substrate by supplying a third raw material containing an aluminum element and carbon, the first raw material, and the second raw material alternately y times to the substrate. The steps of forming
(C) performing steps (A) and (B) alternately z times to form a titanium aluminum carbonitride film on the substrate;
Have
The x, y, and z are integers of 1 or more, respectively, and the ratio of titanium, aluminum, carbon, and nitrogen contained in the titanium aluminum carbonitride film is adjusted by adjusting the values of the x, y, and z. A program for causing the substrate processing apparatus to execute a procedure for modulating the work function of the titanium aluminum carbonitride film to a value in the range of 4.52 to 4.68 eV.