JP2020077890A - Semiconductor device manufacturing method, substrate processing apparatus, and program - Google Patents

Abstract

To control an in-plane film thickness distribution of a film formed on a substrate.SOLUTION: A semiconductor device manufacturing method comprises the step of forming a film on a substrate by performing predetermined times a cycle of performing in a non-simultaneous manner, a step of supplying a material to the substrate to form a first layer and a step of supplying a reactant to the substrate to modify the first layer to form a second layer. In the step of forming the first layer, the following steps are performed in this order: a step of supplying a material to the substrate while supplying inert gas to the substrate at a first flow rate from a first supply part and supplying the inert gas to the substrate at a second flow rate from a second supply part provided adjacent to the first supply part at the same time, and a step of supplying the material while supplying the inert gas to the substrate at a third flow rate lower than each of the first flow rate and the second flow rate from the first supply part, or supplying the material from the first supply part while stopping supply of the inert gas from the first supply part and supplying the inert gas to the substrate at a fourth flow rate from the second supply part.SELECTED DRAWING: Figure 4

Description

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

  As one of the steps of manufacturing a semiconductor device, a process of forming a film on a substrate may be performed (see, for example, Patent Document 1).

JP, 2010-118462, A

  An object of the present invention is to provide a technique capable of controlling the in-plane film thickness distribution of a film formed on a substrate.

According to one aspect of the invention,
(A) supplying a raw material to the substrate to form a first layer,
(B) supplying a reactant to the substrate to modify the first layer to form a second layer,
A step of forming a film on the substrate by performing a predetermined number of non-simultaneous cycles,
In (a),
(A-1) A second supply unit provided adjacent to the first supply unit while supplying the raw material while supplying an inert gas at a first flow rate from the first supply unit to the substrate. And a step of supplying an inert gas at a second flow rate,
(A-2) The raw material is supplied to the substrate while the inert gas is supplied from the first supply unit at a third flow rate smaller than each of the first flow rate and the second flow rate, or Supplying the raw material from the first supply unit while stopping the supply of the inert gas from the first supply unit, and supplying the inert gas at a fourth flow rate from the second supply unit,
Is provided in this order.

  According to the present invention, it is possible to control the in-plane film thickness distribution of the film formed on the substrate.

FIG. 2 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus preferably used in an embodiment of the present invention, showing a processing furnace portion in a vertical sectional view. It is a schematic block diagram of a part of vertical processing furnace of the substrate processing apparatus suitably used in the embodiment of the present invention, and is a view showing a part of the processing furnace in a sectional view taken along the line AA of FIG. 1. It is a schematic block diagram of the controller of the substrate processing apparatus suitably used in the embodiment of the present invention, and is a block diagram showing the control system of the controller. It is a figure which shows the film-forming sequence of one Embodiment of this invention. It is a figure which illustrates the change of the formation rate of the 1st layer on a board. (A) And (b) is a cross-sectional view which shows the modification of a vertical processing furnace, respectively, and is a figure which shows a reaction tube, a buffer chamber, a nozzle, etc. partially extracted. (A) is a figure which shows the evaluation result of the film thickness distribution in a board | substrate in an Example, (b) is a figure which shows the evaluation result of the film thickness distribution in a board | substrate in a comparative example.

<One Embodiment of the Present Invention>
An embodiment of the present invention will be described below with reference to FIGS.

(1) Configuration of Substrate Processing Apparatus As shown in FIG. 1, the processing furnace 202 has a heater 207 as a heating mechanism (temperature adjusting unit). The heater 207 has a cylindrical shape and is vertically installed by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation unit) that activates (excites) gas by heat.

Inside the heater 207, a reaction tube 203 is arranged concentrically with the heater 207. 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 an upper end closed and a lower end opened. Below the reaction tube 203, a manifold 209 is arranged concentrically with the reaction tube 203. The manifold 209 is made of, for example, a metal material such as stainless steel (SUS), and has a cylindrical shape with an open upper end and a lower end. The upper end of the manifold 209 is engaged with the lower end of the reaction tube 203, and is configured to support the reaction tube 203. An O-ring 220a as a seal member is provided between the manifold 209 and the reaction tube 203. The reaction tube 203 is vertically installed like the heater 207. A processing container (reaction container) is mainly configured by the reaction tube 203 and the manifold 209. A processing chamber 201 is formed in the hollow cylindrical portion of the processing container. The processing chamber 201 is configured to be able to accommodate the wafer 200 as a substrate. The wafer 200 is processed in the processing chamber 201.

  A nozzle 249a as a first supply unit and nozzles 249b and 249c as a second supply unit are provided in the processing chamber 201 so as to penetrate a sidewall of the manifold 209. Gas supply pipes 232a to 232c are connected to the nozzles 249a to 249c, respectively. The second supply unit is a supply unit different from the first supply unit, and is provided adjacent to the first supply unit. The nozzles 249a, 249b, 249c are different nozzles, and each of the nozzles 249b, 249c is provided adjacent to the nozzle 249a.

  Mass flow controllers (MFCs) 241a to 241c, which are flow rate controllers (flow rate control units), and valves 243a to 243c, which are open / close valves, are provided in the gas supply pipes 232a to 232c in order from the upstream side of the gas flow. .. Gas supply pipes 232e and 232d are connected to the gas supply pipes 232a and 232b, respectively, on the downstream side of the valves 243a and 243b. The gas supply pipes 232e and 232d are provided with MFCs 241e and 241d and valves 243e and 243d, respectively, in this order from the upstream side of the gas flow.

  As shown in FIG. 2, the nozzles 249a to 249c are arranged in the annular space in a plan view between the inner wall of the reaction tube 203 and the wafer 200, along the upper part of the inner wall of the reaction tube 203 and the upper part of the wafer 200. They are provided so as to rise upward in the arrangement direction. That is, the nozzles 249a to 249c are provided along the wafer arranging region in a region laterally surrounding the wafer arranging region in which the wafers 200 are arranged and horizontally surrounding the wafer arranging region. The nozzle 249a is arranged so as to face the exhaust port 231a, which will be described later, in a straight line with the center of the wafer 200 loaded into the processing chamber 201 interposed therebetween in a plan view. The nozzles 249b and 249c are arranged on both sides of the nozzle 249a so as to sandwich the nozzle 249a from both sides along the inner wall of the reaction tube 203 (outer peripheral portion of the wafer 200). Gas supply holes 250a to 250c for supplying gas are provided on the side surfaces of the nozzles 249a to 249c, respectively. Each of the gas supply holes 250a to 250c is opened so as to face the exhaust port 231a in plan view, and gas can be supplied toward the wafer 200. A plurality of gas supply holes 250a to 250c are provided from the lower part to the upper part of the reaction tube 203.

From the gas supply pipe 232a, as a raw material (raw material gas), for example, a halosilane-based gas containing Si as a predetermined element (main element) constituting the film and a halogen element is processed through the MFC 241a, the valve 243a, and the nozzle 249a. It is supplied into the chamber 201. The raw material gas refers to a raw material in a gaseous state, for example, a gas obtained by vaporizing a raw material in a liquid state at room temperature and atmospheric pressure, a raw material in a gas state at room temperature and atmospheric pressure, and the like. Halosilane is a silane having a halogen group. The halogen group includes a chloro group, a fluoro group, a bromo group, an iodo group and the like. That is, the halogen group includes a halogen element such as chlorine (Cl), fluorine (F), bromine (Br), iodine (I). As the halosilane-based gas, for example, a raw material gas containing Si and Cl, that is, a chlorosilane-based gas can be used. The chlorosilane-based gas acts as a Si source. As the chlorosilane-based gas, for example, hexachlorodisilane (Si ₂ Cl ₆ , abbreviation: HCDS) gas can be used.

From the gas supply pipe 232b, as a reactant (reactant) having a chemical structure (molecular structure) different from that of the raw material, for example, a hydrogen nitride-based gas that is a nitriding gas as a nitrogen (N) -containing gas is supplied to the MFC 241b and the valve 243b, It is supplied into the processing chamber 201 through the nozzle 249b. The hydrogen nitride-based gas acts as an N source. As the hydrogen nitride-based gas, for example, ammonia (NH ₃ ) gas can be used.

From the gas supply pipes 232c to 232e, for example, nitrogen (N ₂ ) gas is supplied as an inert gas through the MFCs 241c to 241e, the valves 243c to 243e, the gas supply pipes 232c to 232a, and the nozzles 249c to 249a, respectively. It is supplied into 201. The N ₂ gas acts as a purge gas, a carrier gas, a diluent gas, and the like, and further acts as a film thickness distribution control gas that controls the in-plane film thickness distribution of the film formed on the wafer 200.

  A raw material supply system is mainly configured by the gas supply pipe 232a, the MFC 241a, and the valve 243a. A reactant supply system is mainly configured by the gas supply pipe 232b, the MFC 241b, and the valve 243b. An inert gas supply system is mainly configured by the gas supply pipes 232c to 232e, the MFCs 241c to 241e, and the valves 243c to 243e.

  Any or all of the various supply systems described above may be configured as an integrated supply system 248 in which valves 243a to 243e and MFCs 241a to 241e are integrated. The integrated supply system 248 is connected to each of the gas supply pipes 232a to 232e, and supplies various gases into the gas supply pipes 232a to 232e, that is, opens and closes the valves 243a to 243e and uses the MFCs 241a to 241e. The flow rate adjusting operation and the like are configured to be controlled by the controller 121 described later. The integrated type supply system 248 is configured as an integrated type or a divided type integrated unit, and can be attached / detached to / from the gas supply pipes 232a to 232e in units of integrated units. It is configured so that maintenance, replacement, expansion, etc. can be performed in units of integrated units.

  Below the side wall of the reaction tube 203, an exhaust port 231a for exhausting the atmosphere in the processing chamber 201 is provided. As shown in FIG. 2, the exhaust port 231a is provided at a position facing (facing) the nozzles 249a to 249c (gas supply holes 250a to 250c) with the wafer 200 interposed therebetween in a plan view. The exhaust port 231a may be provided along the upper part of the side wall of the reaction tube 203, that is, along the wafer array region. An exhaust pipe 231 is connected to the exhaust port 231a. In the exhaust pipe 231, 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 regulator) are provided. A vacuum pump 246 as a vacuum exhaust device is connected. The APC valve 244 can perform vacuum exhaust and vacuum exhaust stop in the processing chamber 201 by opening and closing the valve in a state where the vacuum pump 246 is operated, and further, in a state where the vacuum pump 246 is operated, The pressure inside the processing chamber 201 can be adjusted by adjusting the valve opening degree 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 manifold 209, a seal cap 219 is provided as a furnace port lid that can hermetically close the lower end opening of the manifold 209. The seal cap 219 is made of, for example, a metal material such as SUS and has a disc shape. An O-ring 220b is provided on the upper surface of the seal cap 219 as a seal member that contacts the lower end of the manifold 209. Below the seal cap 219, a rotation mechanism 267 for rotating the boat 217 described later is installed. The rotating shaft 255 of the rotating mechanism 267 penetrates the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the wafer 217 by rotating the boat 217. The seal cap 219 is configured to be vertically moved up and down by a boat elevator 115 as an elevating mechanism installed outside the reaction tube 203. The boat elevator 115 is configured as a transfer device (transfer mechanism) that moves the wafer 200 in and out (transfers) the wafer 200 by moving the seal cap 219 up and down. Below the manifold 209, there is provided a shutter 219s as a furnace port lid that can hermetically close the lower end opening of the manifold 209 in a state where the seal cap 219 is lowered and the boat 217 is carried out from the processing chamber 201. The shutter 219s is made of, for example, a metal material such as SUS and has a disk shape. On the upper surface of the shutter 219s, an O-ring 220c as a sealing member that comes into contact with the lower end of the manifold 209 is provided. The opening / closing operation (elevating operation, rotating operation, etc.) of the shutter 219s is controlled by the shutter opening / closing mechanism 115s.

  The boat 217 as the substrate support is configured to support a plurality of wafers 200, for example, 25 to 200 wafers 200 in a horizontal posture and in a vertically aligned manner with the centers thereof aligned with each other in a multi-stage manner, that is, It is configured to be arranged at intervals. The boat 217 is made of, for example, a heat resistant material such as quartz or SiC. Below the boat 217, a plurality of heat insulating plates 218 made of a heat resistant material such as quartz or SiC are supported in multiple stages.

  A temperature sensor 263 as a temperature detector is installed in the reaction tube 203. The temperature inside the process chamber 201 has a desired temperature distribution by adjusting the degree of energization to the heater 207 based on the temperature information detected by the temperature sensor 263. The temperature sensor 263 is provided along the inner wall of the reaction tube 203.

  As shown in FIG. 3, a 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 done. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to be able to exchange data with the CPU 121a via the internal bus 121e. An input / output device 122 configured as, for example, a touch panel or the like is connected to the controller 121.

  The storage device 121c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 121c, a control program for controlling the operation of the substrate processing apparatus, a process recipe in which a procedure, conditions, etc. of the substrate processing, which will be described later, are stored in a readable manner. The process recipe is a combination that causes the controller 121 to execute each procedure in the substrate processing described below and obtains a predetermined result, and functions as a program. Hereinafter, process recipes, control programs, and the like are collectively referred to simply as programs. In addition, the process recipe is also simply referred to as a recipe. When the word program is used in this specification, it may include only a recipe alone, only a control program alone, or both of them. The RAM 121b is configured as a memory area (work area) in which programs and data read by the CPU 121a are temporarily stored.

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

  The CPU 121a is configured to read and execute the control program from the storage device 121c, and also read the recipe from the storage device 121c in response to input of an operation command from the input / output device 122. The CPU 121a adjusts the flow rates of various gases by the MFCs 241a to 241e, opens and closes the valves 243a to 243e, opens and closes the APC valve 244, and adjusts the pressure by the APC valve 244 based on the pressure sensor 245 so as to follow the contents of the read recipe. Operation, start and stop of the vacuum pump 246, temperature adjustment operation of the heater 207 based on the temperature sensor 263, rotation and rotation speed adjustment operation of the boat 217 by the rotation mechanism 267, raising / lowering operation of the boat 217 by the boat elevator 115, shutter opening / closing mechanism 115s. Is configured to control the opening / closing operation of the shutter 219s.

  The controller 121 can be configured by installing the above program stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, a magnetic disk such as an HDD, an optical disk such as a CD, a magneto-optical disk such as an MO, and a semiconductor memory such as a USB memory. The storage device 121c and the external storage device 123 are configured as a computer-readable recording medium. 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 of them. Note that the program may be provided to the computer by using communication means such as the Internet or a dedicated line without using the external storage device 123.

(2) Substrate Processing Process As an example of a semiconductor device manufacturing process using the substrate processing apparatus described above, a substrate processing sequence example of forming a film on a wafer 200 as a substrate, that is, a film forming sequence example, will be described with reference to FIG. Will be explained. In the following description, the operation of each part of the substrate processing apparatus is controlled by the controller 121.

In the film forming sequence shown in FIG.
Step A (indicated by A in the figure) for supplying HCDS gas as a raw material to the wafer 200,
Step B (indicated by B in the figure) for supplying NH ₃ gas as a reactant to the wafer 200,
The silicon nitride film (SiN film) that is a film containing Si and N is formed as a film on the wafer 200 by performing a predetermined number of non-simultaneous cycles.

In the film forming sequence shown in FIG.
The HCDS gas is supplied to the wafer 200 from the nozzle 249a as the first supply unit at a first flow rate while supplying the N ₂ gas as the inert gas, and the second supply unit is provided adjacent to the nozzle 249a. A1 (indicated by A1 in the figure) for supplying N ₂ gas from the nozzles 249b and 249c at a second flow rate,
To the wafer 200, or to supply the HCDS gas while supplying _{N 2} gas with a small third flow rate than from each of the nozzles 249a of the first flow and the second flow rate, stopping the supply of the _{N 2} gas from the nozzle 249a While supplying the HCDS gas from the nozzle 249a while supplying the N ₂ gas from the nozzles 249b and 249c at the fourth flow rate (shown by A2 in the figure),
By carrying out in this order, the in-wafer film thickness distribution of the SiN film formed on the wafer 200 (hereinafter, also simply referred to as in-plane film thickness distribution) is controlled.

  Here, as an example, as the wafer 200, a bare wafer having a small surface area with no concave-convex structure formed on the surface thereof is used, and the in-plane film thickness distribution of the SiN film is adjusted to the center of the wafer 200 by the above-described film forming sequence and flow rate control. A description will be given of a case where the distribution is thickest in the part and gradually becomes thinner toward the outer peripheral part (peripheral part) (hereinafter, also referred to as central convex distribution). If it is possible to form a film having a central convex distribution on a bare wafer, it is possible to obtain a film thickness variation from the central part to the outer peripheral part on a pattern wafer (product wafer) with a large surface area having a fine uneven structure formed on the surface. It is possible to form a film having a small flat film thickness distribution (hereinafter, also referred to as flat distribution).

In addition, here, as an example, the first flow rate in step A1 is set to be larger than the second flow rate, the supply of N ₂ gas from the nozzle 249a is stopped in step A2 (the third flow rate is set to zero), and A case where the four flow rates are equal to the second flow rate will be described.

  In this specification, the film formation sequence shown in FIG. 4 may be referred to as follows for convenience. The same notation is used in the description of the modified examples and the like below.

(HCDS → NH ₃ ) × n ⇒ SiN

  When the term "wafer" is used in this specification, it may mean the wafer itself or a laminate of the wafer and a predetermined layer or film formed on the surface of the wafer. When the term "wafer surface" is used herein, it may mean the surface of the wafer itself or the surface of a predetermined layer or the like formed on the wafer. In this specification, the description of “forming a predetermined layer on a wafer” means directly forming a predetermined layer on the surface of the wafer itself, a layer formed on the wafer, etc. It may mean that a predetermined layer is formed on. In this specification, the term “substrate” is also synonymous with the term “wafer”.

(Wafer charge and boat load)
When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), the shutter opening / closing mechanism 115s moves the shutter 219s to open the lower end opening of the manifold 209 (shutter open). Thereafter, as shown in FIG. 1, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and loaded into the processing chamber 201 (boat loading). In this state, the seal cap 219 seals the lower end of the manifold 209 via the O-ring 220b.

(Pressure adjustment and temperature adjustment)
The inside of the processing chamber 201, that is, the space in which the wafer 200 exists is evacuated by the vacuum pump 246 (vacuum exhaust) so that the desired pressure (degree of vacuum) is obtained. At this time, the pressure inside 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. Further, the wafer 200 in the processing chamber 201 is heated by the heater 207 so as to have a desired film forming 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. Further, the rotation of the wafer 200 by the rotation mechanism 267 is started. The exhaust of the processing chamber 201, the heating of the wafer 200, and the rotation are all continuously performed at least until the processing of the wafer 200 is completed.

(Film forming step)
Then, the following steps A and B are sequentially executed.

[Step A]
In this step, the HCDS gas is supplied to the wafer 200 in the processing chamber 201. Specifically, the valve 243a is opened to flow the HCDS gas into the gas supply pipe 232a. The flow rate of the HCDS gas is adjusted by the MFC 241a, is supplied into the processing chamber 201 via the nozzle 249a, and is exhausted from the exhaust port 231a. At this time, the HCDS gas is supplied to the wafer 200. In Step A, Steps A1 and A2 of supplying N ₂ gas into the processing chamber 201 via the nozzles 249a to 249c are performed, the details of which will be described later.

As the processing conditions in step A, except for the N ₂ gas supply conditions in steps A1 and A2 described later,
HCDS gas supply flow rate: 0.001 to 2 slm, preferably 0.01 to 1 slm
HCDS gas supply time: 1 to 120 seconds, preferably 1 to 60 seconds Treatment temperature: 250 to 800 ° C, preferably 400 to 700 ° C
Processing pressure: 1 to 2666 Pa, preferably 67 to 1333 Pa
Is exemplified.

By supplying the HCDS gas to the wafer 200 under the above conditions, a Si-containing layer containing Cl is formed as the first layer on the outermost surface of the wafer 200. In the Si-containing layer containing Cl, HCDS is physically adsorbed on the outermost surface of the wafer 200, a substance (hereinafter referred to as Si _x Cl _y ) in which a part of HCDS is decomposed is chemically adsorbed, and HCDS is thermally decomposed. It is formed by depositing Si or the like. The Si-containing layer containing Cl may be an adsorption layer of HCDS or Si _x Cl _y (physical adsorption layer or chemical adsorption layer), or may be a Si layer containing Cl. In the present specification, the Si-containing layer containing Cl is also simply referred to as a Si-containing layer.

Since the Si adsorption sites are abundantly present on the outermost surface of the wafer 200 before the HCDS gas is supplied, as shown in FIG. The first layer is formed, and this relatively large formation rate is maintained for a predetermined period (period T ₁ ). After that, the formation of the first layer proceeds further by continuing the supply of the HCDS gas. However, when the amount of adsorption sites existing on the outermost surface of the wafer 200 decreases, the formation rate of the first layer significantly decreases. Reach the inflection point. After the inflection point is reached, the state in which the formation rate is greatly reduced is maintained for the period until the adsorption of Si on the outermost surface of the wafer 200 is completely saturated (period T ₂ ). Hereinafter, the formation rate of the first layer in the period T ₁ is also referred to as the first rate. In addition, the formation rate of the first layer in the period T ₂ is also referred to as a second rate. The second rate is a rate smaller than the first rate (first rate> second rate).

According to the inventors' earnest research, after the supply of the HCDS gas to the wafer 200 is started and the above-mentioned inflection point is reached, it is necessary to completely saturate the adsorption of Si on the outermost surface of the wafer 200. It has been found that the supply of HCDS gas to 200 needs to be continued for a long time. As one of the factors, it is conceivable that the steric hindrance formed on the surface of the wafer 200 may be eliminated during the film formation process and Si may be adsorbed to the hidden adsorption site. In addition, as another factor, the impurities attached to the adsorption sites existing on the surface of the wafer 200 and acting to inhibit the adsorption of Si to the adsorption sites are desorbed during the progress of the film formation process, It is possible that Si may be adsorbed to the hidden adsorption site. For these reasons, it is necessary to continuously supply the HCDS gas to the wafer 200 for a long time in order to completely saturate the adsorption of Si on the wafer 200, and the period T ₂ is longer than the period T _1. (T ₁ <T ₂ ).

In the present specification, the period T ₁ described above, that is, the state in which the formation rate of the first layer is the first rate and the adsorption of Si contained in the HCDS gas to the base is unsaturated is referred to as a pseudo-unsaturated state. The period during which the adsorption of Si contained in the HCDS gas to the underlayer is in a pseudo-unsaturated state is also referred to as a pseudo-unsaturated period. In addition, the period T ₂ described above, that is, the formation rate of the first layer is the second rate, and the adsorption of Si contained in the HCDS gas to the base is unsaturated, but a state close to saturation is referred to as a pseudo saturation state. The period during which Si contained in the HCDS gas is adsorbed to the underlayer in a pseudo saturation state is also referred to as a pseudo saturation period.

In the period T ₁ , the HCDS gas supplied from the nozzle 249 a is actively consumed in the outer peripheral portion of the wafer 200 and tends to hardly reach the central portion of the wafer 200. Therefore, when the supply of the HCDS gas to the wafer 200 is stopped after the supply of the HCDS gas to the wafer 200 is started, for example, before the inflection point is reached, the distribution of the thickness of the first layer in the plane of the wafer 200 is distributed. (Hereinafter, also referred to as the in-plane thickness distribution of the first layer) is a distribution in which the central portion of the wafer 200 is thinnest and gradually becomes thicker toward the outer peripheral portion (hereinafter also referred to as central concave distribution).

  On the other hand, after the supply of the HCDS gas to the wafer 200 is started, for example, by continuing the supply of the HCDS gas to the wafer 200 for a long time even after reaching the inflection point, the consumption of the HCDS gas at the outer peripheral portion of the wafer 200 is reduced. It is considered that eventually, the amount of HCDS gas reaching the central portion of the wafer 200 can be gradually increased accordingly. Therefore, as one method of approaching the in-plane thickness distribution of the first layer from the central concave distribution to the flat distribution, the supply of the HCDS gas to the wafer 200 is continued for a long time without stopping even after reaching the inflection point. It is possible to do it.

  However, this method causes an increase in gas cost, and increases the period required for step A, that is, the processing time per cycle, that is, the total processing time, resulting in a decrease in the productivity of the film forming process. There is a case. Further, in this method, even if it is theoretically possible to bring the in-plane thickness distribution of the first layer close to the central concave distribution, it is difficult to make it the central convex distribution.

Further, when the HCDS gas is supplied to the wafer 200 in the periods T ₁ and T ₂ , the N ₂ gas is supplied at a large flow rate from each of the nozzles 249b and 249c at the same time, so that the inner wall of the reaction tube 203 and the wafer 200 are supplied. The pressure of the annular space (hereinafter, also simply referred to as “annular space”) in plan view between and is larger than that when N ₂ gas is not supplied at a large flow rate from each of the nozzles 249b and 249c. Is possible. In this case, it is considered that the outflow of HCDS gas to the annular space can be suppressed and the amount of HCDS gas supplied to the central portion of the wafer 200 can be increased. Further, in this case, it is considered that the partial pressure (concentration) of the HCDS gas in the annular space can be reduced and the supply amount of the HCDS gas to the outer peripheral portion of the wafer 200 can be reduced. Therefore, as one method of approaching the in-plane thickness distribution of the first layer from the central concave distribution to the flat distribution, and further to approach the central convex distribution, the nozzles 249b and 249c in the periods T ₁ and T ₂ are selected. It is conceivable to flow N ₂ gas from each at a large flow rate, for example, at a flow rate higher than the flow rate of HCDS gas.

  However, this method may reduce the formation rate of the first layer due to excessive dilution of the HCDS gas, which may lead to a reduction in productivity of the film forming process.

Further, according to the inventors' earnest research, after the supply of the HCDS gas to the wafer 200 is started and before the inflection point is reached, that is, the supply of the N ₂ gas from the nozzles 249b and 249c in the period T ₁ is compared. Even with the control as described above, it may be difficult to change the tendency that the HCDS gas is actively consumed in the outer peripheral portion of the wafer 200 and does not easily reach the central portion of the wafer 200 in the period T ₁ . I know. For example, depending on the type of the source gas, even if the supply of the N ₂ gas from the nozzles 249b and 249c in the period T ₁ is controlled as described above, the in-plane thickness of the first layer formed in the period T ₁ It is known that there is no change in the tendency of the distribution to be a central concave distribution, and it may be difficult to make this distribution a flat distribution or a central convex distribution. As described above, the thickness distribution of the first layer may not be sufficiently controlled by this method alone.

Further, according to the inventors' earnest research, even after the supply of the HCDS gas to the wafer 200 is started and the inflection point is reached, that is, the supply of the N ₂ gas from the nozzles 249b and 249c in the period T ₂ is described above. It is known that it may be difficult to change the in-plane thickness distribution of the first layer formed in the period T ₁ even if the control is performed as described above. For example, depending on the type of source gas, even if the supply of the N ₂ gas from the nozzles 249b and 249c in the period T ₂ is controlled as described above, the in-plane thickness of the first layer formed in the period T ₁ It has also been found that it is difficult to change the tendency of the distribution in the period T ₂ , and it may be difficult to bring the distribution closer to the flat distribution or even the central convex distribution.

Therefore, in the present embodiment, in order to avoid the above-described various problems, in Step A, in the period from when the supply of the HCDS gas to the wafer 200 is started to when the supply of the HCDS gas to the wafer 200 is stopped, Step A1, A2 is performed in this order. Specifically, step A1 is performed until the above-mentioned period T ₁ , that is, until the formation rate of the first layer changes from the first rate to the second rate smaller than the first rate (until the inflection point is reached). It is done during the period including the period. Further, the step A2 is performed during the above-described period T ₂ , that is, after the formation rate of the first layer changes from the first rate to the second rate (after reaching the inflection point). In order to improve the controllability of the in-plane film thickness distribution of the SiN film formed on the wafer 200, it is effective to omit step A2 in the period T ₁ . As described above, since the period T ₁ is shorter than the period T ₂ , the implementation time of step A1 is shorter than the implementation time of step A2.

  The details of steps A1 and A2 will be described below in order.

In step A1, the valves 243e and 243a are opened, HCDS gas is supplied to the wafer 200 from the nozzle 249a while supplying N ₂ gas at the first flow rate, and at the same time, the valves 243d and 243c are opened and adjacent to the nozzle 249a. The N ₂ gas is supplied at a second flow rate from the nozzles 249b and 249c that are provided. The second flow rate here means the total flow rate of the N ₂ gas supplied from each of the nozzles 249b and 249c. The flow rates of the N ₂ gas supplied from the nozzles 249b and 249c can be substantially equal to each other.

In step A1, by controlling the supply of _{N 2} gas from the nozzle 249a, as described above, the _{N 2} gas supplied from the nozzle 249a to act as a carrier gas, the HCDS gas supplied from the nozzle 249a, the wafer It is possible to extrude 200 from the outer peripheral portion toward the central portion. By this action, it is possible to make the amount of HCDS gas reaching the central portion of the wafer 200 in step A1 larger than the amount of HCDS gas reaching the central portion of the wafer 200 in step A2 described later. .. As a result, the concentration of HCDS gas in the central portion of wafer 200 in step A1 can be made higher than the concentration of HCDS gas in the central portion of wafer 200 in step A2. Further, due to the above-described action, in step A1, it is possible to make the amount of HCDS gas reaching the central portion of wafer 200 larger than the amount of HCDS gas reaching the outer peripheral portion of wafer 200. As a result, in step A1, the concentration of HCDS gas in the central portion of wafer 200 can be made higher than the concentration of HCDS gas in the outer peripheral portion of wafer 200. As a result, in step A1, the formation rate of the first layer in the central portion of the wafer 200 can be made higher than the formation rate of the first layer in the outer peripheral portion of the wafer 200. Then, in the period T ₁ , the in-plane thickness distribution of the first layer formed on the wafer 200 can be a flat distribution or a central convex distribution instead of the central concave distribution.

Further, in step A1, by controlling the supply of the N ₂ gas from the nozzles 249b and 249c as described above, the pressure in the annular space described above is made larger than in the case where the above control is not performed. It is possible to suppress the outflow of the HCDS gas into the annular space and increase the supply amount of the HCDS gas to the central portion of the wafer 200. By controlling the supply of the N ₂ gas from the nozzles 249b and 249c as described above, the flow of the N ₂ gas supplied from the nozzles 249b and 249c toward the exhaust port 231a is supplied from the nozzle 249a. It becomes possible to act as a guide for guiding the HCDS gas or the like toward the central portion of the wafer 200. This action also makes it possible to increase the amount of HCDS gas supplied to the central portion of the wafer 200. Further, it is possible to reduce the partial pressure of the HCDS gas in the annular space and reduce the supply amount of the HCDS gas to the outer peripheral portion of the wafer 200. As a result, in step A1, the formation rate of the first layer in the central portion of the wafer 200 is set to be the same as that of the first layer in the central portion of the wafer 200 when the N ₂ gas is not supplied from the nozzles 249b and 249c. It can be higher than the formation rate. Then, the above-described action obtained by the N ₂ gas supplied from the nozzle 249a, that is, the in-plane thickness distribution of the first layer formed on the wafer 200 is set to a flat distribution or a central convex distribution. The effect of doing so can be obtained more reliably.

In step A1, it is desirable that at least one of the first flow rate and the second flow rate, and preferably both, be larger than the supply flow rate of the HCDS gas in step A1. As a result, the above-described effect of making the in-plane thickness distribution of the first layer formed on the wafer 200 a flat distribution or a central convex distribution can be obtained more reliably. Further, in step A1, at least one of the flow rates of the N ₂ gas supplied from each of the nozzles 249b and 249c, and preferably both, are made larger than the supply flow rate of the HCDS gas in step A1. Is desirable. As a result, the above-described effect of making the in-plane thickness distribution of the first layer formed on the wafer 200 a flat distribution or a central convex distribution can be obtained more reliably.

Further, in step A1, as shown in FIG. 4, it is preferable to start the supply of the N ₂ gas from the nozzle 249a prior to the supply of the HCDS gas. That is, it is preferable that the flow of the N ₂ gas from the nozzle 249a toward the central portion of the wafer 200 is generated in advance and then the supply of the HCDS gas to the wafer 200 is started. As a result, the above-described effect of causing the N ₂ gas supplied from the nozzle 249a to act as the carrier gas can be reliably obtained immediately after the start of the supply of the HCDS gas. In addition, it is possible to prevent the HCDS gas concentration from transiently varying in the plane of the wafer 200 when the supply of the HCDS gas is started. As a result, the in-plane thickness distribution of the first layer formed on the wafer 200 in the period T ₁ can be stably and reproducibly controlled.

The processing conditions in step A1 are:
First flow rate (nozzle 249a): 3 to 20 slm, preferably 5 to 10 slm
Second flow rate (total of nozzles 249b and 249c): 3 to 20 slm, preferably 5 to 10 slm
Implementation time of step A1: 1/10 to 1/4 of HCDS gas supply time in step A
Is exemplified. The other processing conditions are the same as the processing conditions in step A described above.

In Step A2, the MFC 241e is adjusted to supply the HCDS gas to the wafer 200 while supplying the N ₂ gas from the nozzle 249a at a third flow rate smaller than each of the first flow rate and the second flow rate, or the valve 243e. Is closed, while the supply of the N ₂ gas from the nozzle 249a is stopped, the HCDS gas is supplied from the nozzle 249a, the MFCs 241d and 241c are adjusted, and the N ₂ gas is supplied from the nozzles 249b and 249c at the fourth flow rate. Like the second flow rate, the third flow rate here means the total flow rate of the N ₂ gas supplied from the nozzles 249b and 249c, respectively. The flow rates of the N ₂ gas supplied from the nozzles 249b and 249c can be substantially equal to each other. As described above, in FIG. 4, as an example, in step A2, the supply of the N ₂ gas from the nozzle 249a is stopped (the third flow rate is set to zero), and the fourth flow rate is equal to the second flow rate. The case where (the fourth flow rate = the second flow rate) is set is shown.

By controlling the supply of the N ₂ gas from the nozzle 249a in step A2 as described above, it is possible to suppress the excessive dilution of the HCDS gas supplied to the wafer 200 from the nozzle 249a. As a result, a decrease in the formation rate of the first layer is suppressed, and a decrease in productivity of the film forming process can be avoided. In addition, when the N ₂ gas is supplied from the nozzle 249a in step A2 (when the third flow rate is not set to zero), the N ₂ gas supplied from the nozzle 249a is caused to act as a carrier gas. The same effect can be obtained in step A2. However, even in this case, it is preferable that the third flow rate be smaller than the supply flow rate of the HCDS gas in step A2. As a result, the above-described effect of suppressing the decrease in the formation rate of the first layer can be reliably obtained. Further, in step A2, when the supply of the N ₂ gas from the nozzle 249a is not performed (when the third flow rate is zero), the above effect of suppressing the decrease in the formation rate of the first layer is more reliable. Will be obtained.

Further, in step A2, by controlling the supply of N ₂ gas from the nozzles 249b and 249c as described above, the supply of HCDS gas to the central portion of the wafer 200 is performed for the same reason as described in step A1. It is possible to increase the amount and reduce the supply amount of the HCDS gas to the outer peripheral portion of the wafer 200. Further, step A1 is performed by causing the flow of the N ₂ gas supplied from the nozzles 249b and 249c toward the exhaust port 231a to act as a guide for guiding the HCDS gas supplied from the nozzle 249a toward the central portion of the wafer 200. The same effect as described above can be obtained in step A2. When the fourth flow rate is set to be higher than the supply flow rate of the HCDS gas in step A2 in step A2, the N ₂ gas supplied from the nozzles 249b and 249c acts as a guide for the HCDS gas in step A1. The effects described above can be obtained more reliably.

The processing conditions in step A2 are:
Third flow rate (nozzle 249a): 0 to 0.8 slm, preferably 0 to 0.2 slm
Fourth flow rate (total of nozzles 249b and 249c): 3 to 20 slm, preferably 5 to 10 slm
Implementation time of step A2: 3/4 to 9/10 of HCDS gas supply time in step A
Is exemplified. The other processing conditions are the same as the processing conditions in step A described above.

After forming the first layer on the wafer 200, the valve 243a is closed and the supply of the HCDS gas into the processing chamber 201 is stopped. Then, the inside of the processing chamber 201 is evacuated to remove gas and the like remaining in the processing chamber 201 from the inside of the processing chamber 201. At this time, the valves 243c to 243e are opened and N ₂ gas is supplied into the processing chamber 201 through the nozzles 249c to 249a. The N ₂ gas supplied from the nozzles 249c to 249a acts as a purge gas, whereby the inside of the processing chamber 201 is purged (purge step). In the purge step, the flow rate of the N ₂ gas supplied from each of the nozzles 249c to 249a is set to fall within the range of 0.1 to ₂ slm, for example. The other processing conditions are the same as the processing conditions in step A described above.

As a raw material, in addition to HCDS gas, monochlorosilane (SiH ₃ Cl, abbreviation: MCS) gas, dichlorosilane (SiH ₂ Cl ₂ , abbreviation: DCS) gas, trichlorosilane (SiHCl ₃ , abbreviation: TCS) gas, tetrachlorosilane A chlorosilane source gas such as (SiCl ₄ , abbreviated: STC) gas, octachlorotrisilane (Si ₃ Cl ₈ , abbreviated: OCTS) gas can be used.

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

[Step B]
After step A is completed, NH ₃ gas is supplied to the wafer 200 in the processing chamber 201, that is, the first layer formed on the wafer 200. Specifically, the valve 243b is opened, and NH ₃ gas is flown into the gas supply pipe 243b. The flow rate of the NH ₃ gas is adjusted by the MFC 241b, is supplied into the processing chamber 201 through the nozzle 249b, and is exhausted from the exhaust port 231a. At this time, NH ₃ gas is supplied to the wafer 200. At this time, at least one of the valves 243c to 243e may be opened to allow the N ₂ gas to flow into the processing chamber 201 through at least one of the nozzles 249c to 249a. Figure 4 shows a case where the supply of _{N 2} gas from the nozzle 249b and not implemented, implementing a nozzle 249a, the supply of _{N 2} gas from the 249 c.

The processing conditions in this step are:
NH ₃ gas supply flow rate: 1 to 10 slm
NH ₃ gas supply time: 1 to 120 seconds, preferably 1 to 60 seconds N ₂ gas supply flow rate (each gas supply pipe): 0 to 2 slm
Processing pressure: 1 to 4000 Pa, preferably 1 to 3000 Pa
Is exemplified. The other processing conditions are the same as the processing conditions in step A.

By supplying the NH ₃ gas to the wafer 200 under the above-described conditions, at least a part of the first layer formed on the wafer 200 is nitrided (modified). By modifying the first layer, a second layer containing Si and N, that is, a SiN layer is formed on the wafer 200. When forming the second layer, impurities such as Cl contained in the first layer form a gaseous substance containing at least Cl in the process of the reforming reaction of the first layer with NH ₃ gas, and It is discharged from inside 201. As a result, the second layer becomes a layer containing less impurities such as Cl than the first layer.

After the second layer is formed, the valve 243b is closed and the supply of NH ₃ gas into the processing chamber 201 is stopped. Then, the gas and the like remaining in the processing chamber 201 are removed from the processing chamber 201 by the same processing procedure and processing conditions as the purging step of step A.

As the reactant, in addition to NH ₃ gas, for example, hydrogen nitride-based gas such as diazene (N ₂ H ₂ ) gas, hydrazine (N ₂ H ₄ ) gas, and N ₃ H ₈ gas can be used.

[Performed a predetermined number of times]
By performing the above-described steps A and B non-simultaneously, that is, without repeating, for a predetermined number of times (n times, n is an integer of 1 or more), a SiN film having a predetermined composition and a predetermined film thickness is formed on the wafer 200. Can be formed. The above cycle is preferably repeated multiple times. That is, the thickness of the second layer formed when the above-described cycle is performed once is made thinner than the desired film thickness, and the SiN film formed by stacking the second layers has the desired film thickness. It is preferred to repeat the above cycle multiple times until the thickness is reached.

(Afterpurge and return to atmospheric pressure)
After the film forming step is completed, N ₂ gas as a purge gas is supplied into the processing chamber 201 from each of the nozzles 249a to 249c and exhausted from the exhaust port 231a. As a result, the inside of the process chamber 201 is purged, and the gas and reaction by-products remaining in the process chamber 201 are removed from the process chamber 201 (afterpurge). After that, the atmosphere in the processing chamber 201 is replaced with an inert gas (replacement with an inert gas), and the pressure in the processing chamber 201 is returned to normal pressure (return to atmospheric pressure).

(Boat unload and wafer discharge)
The boat elevator 115 lowers the seal cap 219 and opens the lower end of the manifold 209. Then, the processed wafer 200 is carried out from the lower end of the manifold 209 to the outside of the reaction tube 203 (boat unloading) while being supported by the boat 217. After the boat is unloaded, the shutter 219s is moved, and the lower end opening of the manifold 209 is sealed by the shutter 219s via the O-ring 220c (shutter close). The processed wafer 200 is carried out of the reaction tube 203 and then taken out from the boat 217 (wafer discharge).

(3) Effects of this Embodiment According to this embodiment, one or more of the following effects can be obtained.

(A) In step A in which the HCDS gas is supplied to the wafer 200 to form the first layer, the in-plane thickness distribution of the first layer can be controlled by performing steps A1 and A2 described above. Becomes As a result, the controllability of the in-plane film thickness distribution of the SiN film formed on the wafer 200 can be improved. For example, the in-plane film thickness distribution of the SiN film formed on the wafer 200 configured as a bare wafer can be made a central convex distribution. This makes it possible to form a SiN film having a flat distribution on the wafer 200 when using a patterned wafer as the wafer 200.

  The in-plane film thickness distribution of the film formed on the wafer 200 depends on the surface area of the wafer 200, which is considered to be due to the so-called loading effect. As the surface area of the wafer 200 to be formed becomes larger, the raw material such as the HCDS gas is consumed in a larger amount in the outer peripheral portion of the wafer 200 and becomes hard to reach the central portion. As a result, the in-plane film thickness distribution of the film formed on the wafer 200 tends to have a central concave distribution. According to the present embodiment, even when a patterned wafer having a large surface area is used as the wafer 200, the in-plane film thickness distribution of the film formed on the wafer 200 is corrected from the central concave distribution to the flat distribution, Further, it is possible to freely control such as correcting to a central convex distribution.

(B) In step A in which the HCDS gas is supplied to the wafer 200 to form the first layer, by performing the above-described steps A1 and A2, the distribution of the composition of the SiN layer in the plane of the wafer 200, that is, the wafer It is possible to control the wafer in-plane composition distribution (hereinafter, also referred to as in-plane composition distribution) of the SiN film formed on 200. As a result, the controllability of the in-plane film quality distribution of the SiN film formed on the wafer 200 (hereinafter, also referred to as in-plane film quality distribution) can be improved.

  For example, when the in-plane film thickness distribution of the SiN film formed on the wafer 200 is a central convex distribution, the composition of the film can be Si-rich in the central portion of the wafer 200 and the peripheral portion of the wafer 200 can be formed. Can make the composition of the film N-rich. Further, for example, when the in-plane film thickness distribution of the SiN film formed on the wafer 200 is a central concave distribution, the film composition can be made N rich in the central portion of the wafer 200, and the outer peripheral portion of the wafer 200 can be formed. In, the composition of the film can be made Si-rich. Further, for example, when the in-plane film thickness distribution of the SiN film formed on the wafer 200 is made flat, the composition of this film can be made uniform over the entire surface of the wafer 200.

  As described above, in this embodiment, the in-plane composition distribution of the SiN film formed on the wafer 200, that is, the in-plane film is controlled by controlling the in-plane film thickness distribution of the SiN film formed on the wafer 200. It is possible to control the quality distribution over a wide range, and for example, it is possible to improve the in-plane uniformity.

(C) In step A2, by controlling the supply of the N ₂ gas from the nozzle 249a as described above, it is possible to reduce the degree of dilution of the HCDS gas and suppress a decrease in the formation rate of the first layer. Becomes As a result, it is possible to suppress a decrease in efficiency of the first layer forming process and avoid a decrease in productivity of the film forming process.

  Further, by making the execution time of step A1 shorter than the execution time of step A2, it becomes possible to more reliably suppress the decrease in the formation rate of the first layer. That is, by making the execution time of step A1 in which the degree of dilution of HCDS gas is large shorter than the execution time of step A2 in which the degree of dilution of HCDS gas is small, it is possible to reduce the total efficiency of the formation processing of the first layer. It is possible to suppress, and it is possible to avoid a decrease in productivity of the film forming process.

(D) By performing steps A1 and A2 under the above-described processing conditions, the partial pressure of the HCDS gas in the processing chamber 201 in step A1 is made smaller than the partial pressure of the HCDS gas in the processing chamber 201 in step A2. It becomes possible to do. By lowering the partial pressure of the HCDS gas in step A1 in this way, it becomes possible to enhance the controllability of the in-plane thickness distribution of the first layer formed in step A1. As described above, the in-plane thickness distribution in the initial stage of forming the first layer can be a major factor in determining the finally obtained in-plane thickness distribution of the first layer. Therefore, the above-mentioned effects are very important in improving the controllability of the in-plane film thickness distribution of the SiN film formed on the wafer 200.

  Further, by reducing the partial pressure of the HCDS gas in step A1 in this way, it becomes possible to improve the step coverage (step coverage characteristic) of the first layer formed in step A1. This makes it possible to improve the step coverage characteristic of the SiN film formed on the wafer 200.

(E) in step A1, the supply of _{N 2} gas from the nozzle 249a, by starting ahead of the supply of the HCDS gas, the above-described effect of the action of _{N 2} gas supplied from the nozzle 249a as a carrier gas Can be reliably obtained immediately after the start of the supply of the HCDS gas. In addition, it is possible to suppress transient variations in the concentration of the HCDS gas within the surface of the wafer 200 when the supply of the HCDS gas is started. As a result, the in-plane thickness distribution of the first layer formed in step A1 can be stably and reproducibly controlled. As described above, the in-plane thickness distribution in the initial stage of forming the first layer can be a major factor in determining the finally obtained in-plane thickness distribution of the first layer. Therefore, the above-mentioned effects are very important in controlling the in-plane film thickness distribution of the SiN film formed on the wafer 200 stably and with good reproducibility.

(F) By arranging the nozzles 249b and 249c on both sides of the nozzle 249a, the controllability of the in-plane thickness distribution of the first layer, that is, the in-plane film of the SiN film formed on the wafer 200 is controlled. The controllability of the thickness distribution can be improved.

(G) By disposing the nozzles 249a to 249c so as to face the exhaust port 231a, respectively, the controllability of the in-plane thickness distribution of the first layer, that is, the in-plane of the SiN film formed on the wafer 200 is controlled. The controllability of the film thickness distribution can be improved.

(H) The above effects can be similarly obtained when a raw material other than HCDS gas is used, a reactant other than NH ₃ gas is used, or an inert gas other than N ₂ gas is used. ..

(4) Modified Example The film forming step in the present embodiment is not limited to the mode shown in FIG. 4, and can be modified as in the modified example shown below. Further, these modified examples can be arbitrarily combined. Unless otherwise specified, the processing procedure and processing conditions at each step of each modification are the same as the processing procedure and processing conditions at each step of the substrate processing sequence described above.

(Modification 1)
In the film formation sequence shown in FIG. 4, in step A1, the supply of _{N 2} gas from the nozzle 249a, an example has been described to start ahead of the supply of the HCDS gas, the supply of _{N 2} gas from the nozzle 249a May be started at the same time as the supply of the HCDS gas. In this case, the processing time per cycle can be shortened and the productivity of the film forming process can be improved as compared with the film forming sequence shown in FIG.

However, in such a case, the concentration of the HCDS gas in the plane of the wafer 200 may transiently change at the start of the supply of the HCDS gas, which may affect the in-plane thickness distribution of the first layer. Therefore, in order to stably and reproducibly control the in-plane thickness distribution of the first layer formed on the wafer 200 in the period T ₁ , as shown in FIG. It is preferable to start the supply of N ₂ gas prior to the supply of HCDS gas.

(Modification 2)
In the film forming sequence shown in FIG. 4, an example (fourth flow rate = second flow rate) in which the fourth flow rate is equal to the second flow rate in step A2 has been described, but the fourth flow rate is set to be smaller than the second flow rate. Good (4th flow rate <2nd flow rate). Further, the fourth flow rate may be set to zero and the supply of N ₂ gas from the nozzles 249b and 249c may be stopped. Alternatively, the fourth flow rate may be larger than the second flow rate (fourth flow rate> second flow rate).

  When the fourth flow rate <the second flow rate in step A2, it is possible to finely adjust the in-plane film thickness distribution of the SiN film formed on the wafer 200, for example, in the direction of weakening the central convex distribution. Become. Further, in step A2, when the fourth flow rate is set to zero, the in-plane film thickness distribution of the SiN film formed on the wafer 200 can be finely adjusted, for example, in a direction to further weaken the degree of central convex distribution. Becomes Further, in step A2, when the fourth flow rate> the second flow rate, the in-plane film thickness distribution of the SiN film formed on the wafer 200 can be finely adjusted, for example, in a direction to increase the degree of the central convex distribution. It will be possible.

  As described above, by adjusting the magnitude of the fourth flow rate in step A2, it becomes possible to finely adjust the in-plane film thickness distribution of the SiN film formed on the wafer 200.

(Modification 3)
In the film forming sequence shown in FIG. 4, the example in which the supply of the N ₂ gas from the nozzle 249a is stopped in step A2 has been described, but as described above, the first flow rate and the second flow rate are respectively supplied from the nozzle 249a. The HCDS gas may be supplied while the N ₂ gas is supplied at a third flow rate that is also smaller and larger than zero. By doing so, it becomes possible to finely adjust the in-plane film thickness distribution of the SiN film formed on the wafer 200, for example, in a direction in which the degree of the central convex distribution is strengthened.

(Modification 4)
As a raw material, for example, an alkylhalosilane raw material gas such as 1,1,2,2-tetrachloro-1,2-dimethyldisilane ((CH ₃ ) ₂ Si ₂ Cl ₄ , abbreviated as TCDMDS) gas, or trisdimethyl. Aminosilane source gas such as aminosilane (Si [N (CH ₃ ) ₂ ] ₃ H, abbreviated as 3DMAS) gas or bisdiethylaminosilane (SiH ₂ [N (C ₂ H ₅ ) ₂ ] ₂ , abbreviated as BDEAS) gas is used. You may use.

In addition, as a reactant, for example, an amine-based gas such as triethylamine ((C ₂ H ₅ ) ₃ N, abbreviation: TEA) gas, oxygen (O ₂ ) gas, water vapor (H ₂ O gas), ozone (O 2 ₃ ) gas, plasma-excited O ₂ gas (O ₂ ^* ), O-containing gas (oxidizer) such as O ₂ gas + hydrogen (H ₂ ) gas, or propylene (C ₃ H ₆ ) gas A C-containing gas or a B-containing gas such as trichloroborane (BCl ₃ ) gas may be used.

  Then, the silicon oxynitride film (SiON film), the silicon oxycarbonitride film (SiOCN film), the silicon oxycarbide film (SiOC film), the silicon carbonitride film (SiCN film) is formed on the wafer 200 by the following film formation sequence, for example. ), A silicon borocarbonitride film (SiBCN film), a silicon boronitride film (SiBN film), and a silicon oxide film (SiO film).

(HCDS → NH ₃ → O ₂ ) × n ⇒ SiON
(HCDS → TEA → O ₂ ) × n ⇒ SiOC (N)
(HCDS → C ₃ H ₆ → NH ₃ ) × n ⇒ SiCN
(HCDS → C ₃ H ₆ → NH ₃ → O ₂ ) × n ⇒ SiOCN
(HCDS → C ₃ H ₆ → BCl ₃ → NH ₃ ) × n ⇒ SiBCN
(HCDS → BCl ₃ → NH ₃ ) × n ⇒ SiBN
(HCDS → O ₂ + H ₂ ) × n ⇒ SiO
(3DMAS → O ₃ ) × n ⇒ SiO
(BDEAS → O ₂ ^* ) × n ⇒ SiO

  Also in these film forming sequences, the same effects as these can be obtained by performing steps A1 and A2 in the same manner as the film forming sequence shown in FIG. The processing procedure and processing conditions for supplying the raw materials and the reactants can be the same as those of the film forming sequence shown in FIG. 4 and the above-described modifications.

<Other Embodiments>
The embodiments of the present invention have 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 invention.

  In the above-described embodiment, an example in which the second supply unit has the nozzles 249b and 249c and these nozzles are arranged on both sides of the nozzle 249a as the first supply unit is described, but the present invention is not limited to this. It is not limited to such an aspect. For example, the second supply unit may have only the nozzle 249b, and the nozzle 249b may be arranged close to or apart from the nozzle 249a. Even in this case, the same effects as those can be obtained by performing steps A1 and A2 in the same manner as the film forming sequence shown in FIG. However, the nozzle arrangement in the above-described embodiment is preferable in that the controllability of the in-plane film thickness distribution of the film formed on the wafer 200 can be improved.

  In the above-described embodiment, an example in which steps A1 and A2 are performed at the time of supplying the raw material has been described, but the present invention is not limited to such an aspect. For example, steps A1 and A2 may be performed when the reactant is supplied instead of when the HCDS gas is supplied. In this case, it is possible to control the concentration distribution of N, C, O, B, etc. in the surface of the wafer 200 of the film formed on the wafer 200. Steps A1 and A2 performed at the time of supplying the reactant can be performed under the same processing conditions and procedures as those of the film forming sequence shown in FIG. 4 and steps A1 and A2 shown in each of the above-described modifications.

In the above embodiment, an example in which the reactant such as NH ₃ gas is supplied from the nozzle 249b has been described, but the present invention is not limited to such an aspect. For example, the reactants may be supplied from both nozzles 249b and 249c. Further, a nozzle different from the nozzles 249a to 249c may be newly provided in the processing chamber 201, and the reactant may be supplied using the newly provided nozzle. Even in these cases, the same effects as these can be obtained by performing steps A1 and A2 at the time of supplying the raw material in the same manner as the film forming sequence shown in FIG.

  In the above-described embodiment, an example of forming a film containing Si as a main element on the substrate has been described, but the present invention is not limited to such an aspect. That is, the present invention can be suitably applied to the case where a film containing a metalloid element such as germanium (Ge) or boron (B) as a main element in addition to Si is formed on the substrate. In addition, the present invention provides titanium (Ti), zirconium (Zr), hafnium (Hf), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), yttrium (Y), lanthanum (La). It can also be suitably applied to the case where a film containing a metal element such as strontium (Sr) or aluminum (Al) as a main element is formed on a substrate.

For example, titanium tetrachloride (TiCl ₄ ) gas or trimethylaluminum (Al (CH ₃ ) ₃ , abbreviated as TMA) gas is used as a raw material, and a titanium nitride film (TiN film) is formed on the substrate by the following film formation sequence. ), Titanium oxynitride film (TiON film), titanium aluminum carbonitride film (TiAlCN film), titanium aluminum carbide film (TiAlC film), titanium carbonitride film (TiCN film), titanium oxide film (TiO film), etc. Also in this case, the present invention can be suitably applied.

(TiCl ₄ → NH ₃ ) × n ⇒ TiN
(TiCl ₄ → NH ₃ → O ₂ ) × n ⇒ TiON
(TiCl ₄ → TMA → NH ₃ ) × n ⇒ TiAlCN
(TiCl ₄ → TMA) × n ⇒ TiAlC
(TiCl ₄ → TEA) × n ⇒ TiCN
(TiCl ₄ → H ₂ O) × n ⇒ TiO

  It is preferable that the recipe used for the substrate processing is individually prepared according to the processing content and stored in the storage device 121c via the telecommunication line or the external storage device 123. Then, when starting the processing, it is preferable that the CPU 121a appropriately selects an appropriate recipe from a plurality of recipes stored in the storage device 121c according to the content of the substrate processing. As a result, it becomes possible to form films of various film types, composition ratios, film qualities, and film thicknesses with good reproducibility with one substrate processing apparatus. Further, the burden on the operator can be reduced, and the processing can be started quickly while avoiding an operation error.

  The above-mentioned recipe is not limited to a case of newly creating the recipe, but may be prepared by changing an existing recipe already installed in the substrate processing apparatus, for example. When changing the recipe, the changed recipe may be installed in the substrate processing apparatus via an electric communication line or a recording medium recording the recipe. Further, the input / output device 122 included in the existing substrate processing apparatus may be operated to directly change the existing recipe already installed in the substrate processing apparatus.

  In the above-described embodiment, the example in which the first and second supply units are provided in the processing chamber along the inner wall of the reaction tube has been described. However, the invention is not limited to the embodiments described above. For example, as shown in the sectional structure of the vertical processing furnace in FIG. 6A, a buffer chamber is provided on the side wall of the reaction tube, and the first and second supply units having the same configuration as the above-described embodiment are provided in the buffer chamber. May be provided in the same arrangement as the above-described embodiment. FIG. 6A shows an example in which a supply buffer chamber and an exhaust buffer chamber are provided on the side wall of the reaction tube, and they are arranged at positions facing each other across the wafer. Each of the supply buffer chamber and the exhaust buffer chamber is provided from the lower part of the side wall of the reaction tube to the upper part thereof, that is, along the wafer array region. Further, FIG. 6A shows an example in which the supply buffer chamber is divided into a plurality of (three) spaces and each nozzle is arranged in each space. The arrangement of the three spaces in the buffer chamber is the same as the arrangement of the first and second supply units. Further, for example, as shown in the sectional structure of the vertical processing furnace in FIG. 6B, the buffer chamber is provided in the same arrangement as in FIG. 6A, the first supply unit is provided in the buffer chamber, and the buffer chamber You may make it provide a 2nd supply part so that the communication part with a process chamber may be pinched | interposed from both sides and along an inner wall of a reaction tube. The configuration other than the buffer chamber and the reaction tube described in FIGS. 6A and 6B is the same as the configuration of each part of the processing furnace shown in FIG. Even when these processing furnaces are used, the same effect as that of the above-described embodiment can be obtained.

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

  Even when these substrate processing apparatuses are used, film formation can be performed under the same sequence and processing conditions as those of the above-described embodiment and modification, and the same effects as these can be obtained.

  Further, the above-described embodiments and modified examples can be appropriately combined and used. The processing procedure and processing condition at this time can be the same as the processing procedure and processing condition of the above-described embodiment, for example.

  The SiN film and the like formed by the methods of the above-described embodiments and modified examples can be widely used as an insulating film, a spacer film, a mask film, a charge storage film, a stress control film, and the like. In recent years, with the miniaturization of semiconductor devices, demands for in-plane film thickness uniformity on films formed on a wafer have become strict. The present invention capable of forming a film having a flat distribution on a patterned wafer having a high-density pattern formed on its surface is considered to be very useful as a technique for responding to this demand.

  Hereinafter, experimental results that support the effects obtained in the above-described embodiment will be described.

As Examples 1 to 3, the substrate processing apparatus shown in FIG. 1 was used to form SiN films on a plurality of wafers by the film forming sequence shown in FIG. In Examples 1 to 3, in step A1, the flow rate (first flow rate) of the N ₂ gas supplied from one nozzle as the first supply unit is set to 10 slm, and the two nozzles as the second supply unit are set. The total flow rate (second flow rate) of the N ₂ gas supplied from 1 was set to 1 slm (0.5 slm × 2), 4 slm (2 slm × 2), and 10 slm (5 slm × 2) in order. In step A2, the supply of N ₂ gas from one nozzle serving as the first supply unit is stopped, and the total flow rate of the N ₂ gas supplied from the two nozzles serving as the second supply unit (fourth Flow rate) was set to the same flow rate as the second flow rate. The other processing conditions were predetermined conditions within the processing condition range described in the above embodiment.

As Comparative Examples 1 to 3, using the substrate processing apparatus shown in FIG. 1, a cycle in which the step of supplying the HCDS gas to the wafer and the step of supplying the NH ₃ gas to the wafer are non-simultaneously performed a predetermined number of times By doing so, a SiN film was formed on a plurality of wafers. In these comparative examples, steps A1 and A2 were not performed, and the supply of N ₂ gas from the first supply part and the second supply part was controlled as follows. That is, in Comparative Examples 1 and 2, in the step of supplying the HCDS gas to the wafer, the supply of N ₂ gas from one nozzle as the first supply unit was stopped, and the two as the second supply unit were stopped. The total flow rate of the N ₂ gas supplied from the nozzle was set to 0.2 slm (0.1 slm × 2) and 10 slm (5 slm × 2) in order. In Comparative Example 3, in the step of supplying the HCDS gas to the wafer, the flow rate of the N ₂ gas supplied from one nozzle as the first supply unit was set to 10 slm, and the two as the second supply unit were supplied. The total flow rate of N ₂ gas supplied from the nozzle was set to 0.2 slm (0.1 slm × 2). The other processing conditions were the same as the processing conditions in the examples.

  Then, the in-plane film thickness distributions of the SiN films in Examples 1 to 3 and Comparative Examples 1 to 3 were measured. The measurement results are shown in FIGS. 7 (a) and 7 (b). The vertical axis in each of FIGS. 7A and 7B is the ratio of the film thickness of the SiN film at the measurement position to the film thickness of the SiN film on the wafer outer peripheral portion (measurement position film thickness / wafer outer peripheral film thickness). Is shown. The horizontal axes of FIGS. 7A and 7B indicate the distance [mm] from the center of the wafer at the measurement position. 7 (a), the symbols ◆, ■, and ▲ indicate the measurement results of Examples 1 to 3, and the symbols ◆, ■, and ▲ in FIG. 7 (b) indicate Comparative Example 1 respectively. The measurement results of ~ 3 are shown.

  According to FIG. 7A, it can be seen that the in-plane film thickness distribution of the SiN film in Example 3 exhibits a strong central convex distribution, and the degree of central convex distribution weakens in the order of Examples 2 and 1. That is, in step A1, the second flow rate is adjusted between the high flow rate and the low flow rate with the first flow rate set to the high flow rate, so that the center of the in-plane film thickness distribution of the SiN film formed on the wafer is adjusted. It can be seen that it is possible to control the in-plane film thickness distribution over a wide range by increasing or decreasing the degree of the convex distribution.

  According to FIG. 7B, the in-plane film thickness distributions of the SiN films in Comparative Examples 1 to 3 do not show a central convex distribution, and all show a tendency to be thickest in the outer peripheral portion, Further, it can be seen that in some comparative examples, the degree of central concave distribution is extremely strong. It can be seen that with the film forming methods used in Comparative Examples 1 to 3, it is difficult to control the in-plane film thickness distribution of the SiN film formed on the wafer such as a flat distribution or a central convex distribution. ..

<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) supplying a raw material to the substrate to form a first layer,
(B) supplying a reactant to the substrate to modify the first layer to form a second layer,
A step of forming a film on the substrate by performing a predetermined number of non-simultaneous cycles,
In (a),
(A-1) A second supply unit provided adjacent to the first supply unit while supplying the raw material while supplying an inert gas at a first flow rate from the first supply unit to the substrate. And a step of supplying an inert gas at a second flow rate,
(A-2) The raw material is supplied to the substrate while the inert gas is supplied from the first supply unit at a third flow rate smaller than each of the first flow rate and the second flow rate, or Supplying the raw material from the first supply unit while stopping the supply of the inert gas from the first supply unit, and supplying the inert gas at a fourth flow rate from the second supply unit,
There is provided a method for manufacturing a semiconductor device or a method for processing a substrate, in which

(Appendix 2)
The method according to Appendix 1, preferably,
The implementation time of (a-1) is set shorter than the implementation time of (a-2).

(Appendix 3)
The method according to Appendix 1 or 2, preferably,
The partial pressure of the raw material in (a-1) is made smaller than the partial pressure of the raw material in (a-2).

(Appendix 4)
The method according to any one of appendices 1 to 3, preferably,
(A-1) is performed during a period in which the adsorption state (to the underlayer) of the main element contained in the raw material and constituting the film is in the pseudo-unsaturated state. Further, (a-2) is performed during a period in which the adsorbed state (on the underlayer) of the main element forming the film contained in the raw material is in the pseudo saturation state. Note that (a-2) is not performed during the period when the adsorption state (to the underlayer) of the main element forming the film contained in the raw material is in the pseudo-unsaturated state.

(Appendix 5)
The method according to any one of appendices 1 to 4, preferably,
(A-1) is performed during a period until the formation rate of the first layer changes from the first rate to a second rate smaller than the first rate. Further, (a-2) is performed in a period after the formation rate of the first layer changes from the first rate to the second rate smaller than the first rate. Note that (a-2) is not performed during the period until the formation rate of the first layer changes from the first rate to the second rate smaller than the first rate.

(Appendix 6)
The method according to any one of appendices 1 to 5, preferably:
The amount of the raw material reaching the central portion of the substrate in (a-1) is made larger than the amount of the raw material reaching the central portion of the substrate in (a-2).

(Appendix 7)
The method according to any one of appendices 1 to 6, preferably
In (a-1), the amount of the raw material reaching the central portion of the substrate is made larger than the amount of the raw material reaching the outer peripheral portion (peripheral portion) of the substrate.

(Appendix 8)
The method according to any one of appendices 1 to 7, preferably:
The concentration of the raw material in the central portion of the substrate in (a-1) is made higher than the concentration of the raw material in the central portion of the substrate in (a-2).

(Appendix 9)
The method according to any one of appendices 1 to 8, preferably:
In (a-1), the concentration of the raw material in the central portion of the substrate is made higher than the concentration of the raw material in the outer peripheral portion (peripheral portion) of the substrate.

(Appendix 10)
The method according to any one of appendices 1 to 9, preferably,
The fourth flow rate is made equal to the second flow rate. Alternatively, the fourth flow rate is made smaller than the second flow rate. Alternatively, the fourth flow rate is made larger than the second flow rate. In this way, by adjusting the fourth flow rate, the film thickness distribution of the film formed on the substrate in the plane of the substrate is finely adjusted.

(Appendix 11)
The method according to any one of appendices 1 to 10, preferably,
In (a-1), the supply of the inert gas from the first supply unit is started prior to the supply of the raw material.

(Appendix 12)
The method according to any one of appendices 1 to 11, preferably,
The second supply unit has a plurality of supply units, and they are arranged on both sides of the first supply unit with the first supply unit interposed therebetween.

(Appendix 13)
The method according to any one of appendices 1 to 12, preferably
Each of the first flow rate and the second flow rate is made larger than the supply flow rate of the raw material in (a-1).

(Appendix 14)
The method according to any one of appendices 1 to 13, preferably,
The fourth flow rate is set higher than the supply flow rate of the raw material in (a-2).

(Appendix 15)
The method according to any one of appendices 1 to 14, preferably,
The third flow rate is smaller than the supply flow rate of the raw material in (a-2).

(Appendix 16)
The method according to any one of appendices 1 to 15, preferably
In (a-2), the supply of the inert gas from the first supply unit is stopped. That is, the third flow rate is set to zero.

(Appendix 17)
According to another aspect of the invention,
A processing chamber in which the substrate is processed,
A raw material supply system for supplying a raw material to the substrate in the processing chamber,
A reactant supply system for supplying a reactant to the substrate in the processing chamber;
An inert gas supply system for supplying an inert gas to the substrate in the processing chamber,
In the processing chamber, (a) a process of supplying the raw material to the substrate to form a first layer, and (b) a process of supplying the reactant to the substrate to modify the first layer to form a first layer. A process of forming a film on the substrate is performed by performing a cycle of performing the process of forming two layers non-simultaneously a predetermined number of times. In (a), (a-1) A process of supplying the raw material while supplying an inert gas at a first flow rate from a first supply section, and supplying an inert gas at a second flow rate from a second supply section provided adjacent to the first supply section. And (a-2) whether to supply the raw material to the substrate while supplying an inert gas from the first supply unit at a third flow rate smaller than each of the first flow rate and the second flow rate. A process of supplying the raw material from the first supply unit while stopping the supply of the inert gas from the first supply unit, and supplying the inert gas at a fourth flow rate from the second supply unit. A control unit configured to control the raw material supply system, the reactant supply system, and the inert gas supply system so as to be performed in this order,
A substrate processing apparatus having the following is provided.

(Appendix 18)
According to yet another aspect of the invention,
In the processing chamber of the substrate processing apparatus,
(A) a procedure of supplying a raw material to a substrate to form a first layer,
(B) supplying a reactant to the substrate to modify the first layer to form a second layer,
A step of forming a film on the substrate by performing a predetermined number of non-simultaneous cycles,
In (a),
(A-1) A second supply unit provided adjacent to the first supply unit while supplying the raw material while supplying an inert gas at a first flow rate from the first supply unit to the substrate. From the second flow rate of the inert gas,
(A-2) The raw material is supplied to the substrate while the inert gas is supplied from the first supply unit at a third flow rate smaller than each of the first flow rate and the second flow rate, or A step of supplying the raw material from the first supply part while stopping the supply of the inert gas from the first supply part, and supplying the inert gas at a fourth flow rate from the second supply part;
And the procedure to do in this order,
There is provided a program for causing the substrate processing apparatus to execute the program by a computer, or a computer-readable recording medium recording the program.

200 wafers (substrates)
249a nozzle (first supply unit)
249b nozzle (second supply unit)
249c Nozzle (second supply section)

Claims (19)

(A) supplying a raw material to the substrate to form a first layer,
(B) supplying a reactant to the substrate to modify the first layer to form a second layer,
A step of forming a film on the substrate by performing a predetermined number of non-simultaneous cycles,
In (a),
(A-1) A second supply unit provided adjacent to the first supply unit while supplying the raw material while supplying an inert gas at a first flow rate from the first supply unit to the substrate. And a step of supplying an inert gas at a second flow rate,
(A-2) The raw material is supplied to the substrate while the inert gas is supplied from the first supply unit at a third flow rate smaller than each of the first flow rate and the second flow rate, or Supplying the raw material from the first supply unit while stopping the supply of the inert gas from the first supply unit, and supplying the inert gas at a fourth flow rate from the second supply unit,
In this order,
A method of manufacturing a semiconductor device, wherein (a-1) is performed during a period in which the formation rate of the first layer changes from the first rate to a second rate smaller than the first rate.   The method of manufacturing a semiconductor device according to claim 1, wherein (a-2) is performed in a period after the formation rate of the first layer changes from the first rate to a second rate smaller than the first rate.   The method of manufacturing a semiconductor device according to claim 1, wherein (a-1) is performed during a period in which an adsorbed state of a main element contained in the raw material and forming the film is in a pseudo-unsaturated state.   4. The method of manufacturing a semiconductor device according to claim 1, wherein (a-2) is performed during a period in which an adsorbed state of a main element contained in the raw material and forming the film is in a pseudo saturation state.   The amount of the raw material reaching the central portion of the substrate in (a-1) is made larger than the amount of the raw material reaching the central portion of the substrate in (a-2). 7. The method for manufacturing a semiconductor device according to any one of items.   In (a-1), the arrival amount of the raw material to the central portion of the substrate is made larger than the arrival amount of the raw material to the outer peripheral portion of the substrate. Method of manufacturing semiconductor device.   7. The concentration of the raw material in the central portion of the substrate in (a-1) is made higher than the concentration of the raw material in the central portion of the substrate in (a-2). A method of manufacturing a semiconductor device according to item 1.   In (a-1), the concentration of the raw material in the central portion of the substrate is set higher than the concentration of the raw material in the outer peripheral portion of the substrate, the manufacturing of the semiconductor device according to claim 1. Method.   The manufacturing of the semiconductor device according to claim 1, wherein the fourth flow rate is adjusted to finely adjust the film thickness distribution of the film formed on the substrate within the surface of the substrate. Method.   In (a-1), the method for manufacturing a semiconductor device according to claim 1, wherein the supply of the inert gas from the first supply unit is started prior to the supply of the raw material. ..   The method for manufacturing a semiconductor device according to claim 1, wherein the execution time of (a-1) is shorter than the execution time of (a-2).   The method for manufacturing a semiconductor device according to claim 1, wherein the partial pressure of the raw material in (a-1) is made smaller than the partial pressure of the raw material in (a-2).   13. The method of manufacturing a semiconductor device according to claim 1, wherein the second supply unit has a plurality of supply units, and these are arranged on both sides of the first supply unit with the first supply unit interposed therebetween.   14. The method of manufacturing a semiconductor device according to claim 1, wherein each of the first flow rate and the second flow rate is made larger than a supply flow rate of the raw material in (a-1).   The method for manufacturing a semiconductor device according to claim 1, wherein the fourth flow rate is set to be higher than the supply flow rate of the raw material in (a-2).   The method for manufacturing a semiconductor device according to claim 1, wherein the third flow rate is set to be smaller than the supply flow rate of the raw material in (a-2).   17. In (a-2), the method of manufacturing a semiconductor device according to claim 1, wherein the supply of the inert gas from the first supply unit is stopped and the third flow rate is set to zero. A processing chamber in which the substrate is processed,
A raw material supply system for supplying a raw material to the substrate in the processing chamber,
A reactant supply system for supplying a reactant to the substrate in the processing chamber;
An inert gas supply system for supplying an inert gas to the substrate in the processing chamber,
In the processing chamber, (a) a process of supplying the raw material to the substrate to form a first layer, and (b) a process of supplying the reactant to the substrate to modify the first layer to form a first layer. A process of forming a film on the substrate is performed by performing a cycle of performing the process of forming two layers non-simultaneously a predetermined number of times. In (a), (a-1) A process of supplying the raw material while supplying an inert gas at a first flow rate from a first supply section, and supplying an inert gas at a second flow rate from a second supply section provided adjacent to the first supply section. And (a-2) whether to supply the raw material to the substrate while supplying an inert gas from the first supply unit at a third flow rate smaller than each of the first flow rate and the second flow rate. A process of supplying the raw material from the first supply unit while stopping the supply of the inert gas from the first supply unit, and supplying the inert gas at a fourth flow rate from the second supply unit. The raw material supply system is set to perform in this order, and (a-1) is performed in a period until the formation rate of the first layer changes from the first rate to a second rate smaller than the first rate. A control unit configured to control the reactant supply system and the inert gas supply system,
A substrate processing apparatus having. In the processing chamber of the substrate processing apparatus,
(A) a procedure of supplying a raw material to a substrate to form a first layer,
(B) supplying a reactant to the substrate to modify the first layer to form a second layer,
A step of forming a film on the substrate by performing a predetermined number of non-simultaneous cycles,
In (a),
(A-1) A second supply unit provided adjacent to the first supply unit while supplying the raw material while supplying an inert gas at a first flow rate from the first supply unit to the substrate. From the second flow rate of the inert gas,
(A-2) The raw material is supplied to the substrate while the inert gas is supplied from the first supply unit at a third flow rate smaller than each of the first flow rate and the second flow rate, or A step of supplying the raw material from the first supply part while stopping the supply of the inert gas from the first supply part, and supplying the inert gas at a fourth flow rate from the second supply part;
And the procedure to do in this order,
Performing (a-1) in a period until the formation rate of the first layer changes from the first rate to a second rate smaller than the first rate,
A program that causes the substrate processing apparatus to execute the program.