JP6752976B2 - Semiconductor device manufacturing methods, substrate processing devices and programs - Google Patents

Description

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

As one step in the manufacturing process of the semiconductor device, a film forming process for forming a nitride film on a pattern including recesses such as holes and trenches formed on the surface of the substrate may be performed (see, for example, Patent Document 1).

International Publication No. 2006/088062

An object of the present invention is that when a nitride film is formed on a pattern including a recess formed on the surface of a substrate, the nitride film can be formed on the upper portion of the recess while holding a desired non-deposited region in the recess. Technology is to be provided.

According to one aspect of the invention
(A) A step of forming a first layer by supplying a raw material gas containing an amino group to a substrate having a recess on the surface.
(B) A step of nitriding the first layer by supplying a hydrogen nitride-based gas to the substrate to form an NH-terminated second layer.
(C) By plasma-exciting and supplying nitrogen gas to the substrate, a part of the NH terminal in the second layer is modified to an N terminal, which is different from the part of the NH terminal. The process of maintaining the NH terminal without modifying a part of the N terminal, and
By repeating the cycle of performing the above non-simultaneously, a step of forming a nitride film on the substrate is provided.
In (c), a technique is provided in which the N termination rate at the upper part of the recess of the second layer is higher than the N termination rate at the bottom of the recess of the second layer.

According to the present invention, when a nitride film is formed on a pattern including a recess formed on the surface of a substrate, it is possible to form a nitride film on the upper portion of the recess while holding a desired non-deposited region in the recess. It becomes.

It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus preferably used in one Embodiment of this invention, and is the figure which shows the processing furnace part in the vertical sectional view. It is a schematic block diagram of the vertical processing furnace of the substrate processing apparatus preferably used in one Embodiment of this invention, and is the figure which shows the processing furnace part in the cross-sectional view taken along line AA of FIG. It is a schematic block diagram of the controller of the substrate processing apparatus preferably used in one Embodiment of this invention, and is the figure which shows the control system of the controller by the block diagram. It is a figure which shows the film formation sequence of one Embodiment of this invention. (A) is a schematic view showing the surface state of the second layer formed on the upper part of the trench, and (b) is a schematic view showing the surface state of the second layer formed on the bottom of the trench, (c). ) Is a schematic view showing how a part of the NH termination in the second layer formed in the upper part of the trench is modified, and (d) is a schematic diagram showing the modification of the NH termination in the second layer formed in the bottom of the trench. It is a schematic diagram which shows the state of maintaining without causing, (e) is a schematic diagram which shows the state which the raw material gas is supplied to the modified 2nd layer formed in the upper part of a trench, and is (f). ) Is a schematic view showing how the raw material gas is supplied to the second layer formed at the bottom of the trench. (A) to (c) are enlarged cross-sectional views of a wafer showing a state in which a cap film is being formed on a substrate in which a pattern including a trench is formed on the surface, and (d) is a cross-sectional enlarged view of the wafer. It is a cross-sectional enlarged view of the wafer which shows the appearance that the air gap was formed in the trench by forming. It is a figure which shows the film formation sequence of another embodiment of this invention.

<One Embodiment of the present invention>
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4, 5 (a) to 5 (f), and 6 (a) to 6 (d).

(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, for example, 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 a metal material such as stainless steel (SUS), and is formed in a cylindrical shape with open upper and lower ends. 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.

Nozzles 249a and 249b are provided in the processing chamber 201 so as to penetrate the side wall of the manifold 209. Gas supply pipes 232a and 232b are connected to the nozzles 249a and 249b, respectively.

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

As shown in FIG. 2, the nozzles 249a and 249b are arranged in an 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 from the lower part of the wafer 200. Each is provided so as to stand up in the loading direction. That is, the nozzles 249a and 249b are respectively provided along the wafer arrangement region in a region horizontally surrounding the wafer arrangement region on the side of the wafer arrangement region in which the wafers 200 are arranged. Gas supply holes 250a and 250b for supplying gas are provided on the side surfaces of the nozzles 249a and 249b, respectively. The gas supply hole 250a is opened so as to face the center of the reaction tube 203, and gas can be supplied toward the wafer 200. The gas supply hole 250b is opened so as to face the center of the buffer chamber 237, which will be described later. A plurality of gas supply holes 250a and 250b are provided from the lower part to the upper part of the reaction tube 203.

The nozzle 249b is provided in the buffer chamber 237, which is a gas dispersion space. The buffer chamber 237 is formed between the inner wall of the reaction tube 203 and the partition wall 237a. The buffer chamber 237 (partition wall 237a) is provided in an annular space in a plan view between the inner wall of the reaction tube 203 and the wafer 200, and in a portion extending from the lower part to the upper part of the inner wall of the reaction tube 203 in the loading direction of the wafer 200. It is provided along. That is, the buffer chamber 237 (partition wall 237a) is provided along the wafer arrangement region in the region horizontally surrounding the wafer arrangement region on the side of the wafer arrangement region. A gas supply hole 250c for supplying gas is provided at the end of the surface of the partition wall 237a facing (adjacent to) the wafer 200. The gas supply hole 250c is opened so as to face the center of the reaction tube 203, and gas can be supplied toward the wafer 200. A plurality of gas supply holes 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 gas, that is, an aminosilane-based gas containing silicon (Si) as a main element constituting a film to be formed and an amino group as a raw material gas containing an amino group, MFC241a and a valve 243a , Is supplied into the processing chamber 201 via the nozzle 249a. The raw material gas is a raw material in a gaseous state, for example, a gas obtained by vaporizing a raw material in a liquid state under normal temperature and pressure, a raw material in a gaseous state under normal temperature and pressure, and the like. Aminosilane-based gas includes aminosilane containing chlorine (Cl) (silane having both chloro group and amino group), but the aminosilane-based gas in the present embodiment is Cl-free (Cl-free) aminosilane-based gas. Can be used. More preferably, a halogen-free (halogen-free) aminosilane-based gas can be used. The aminosilane gas acts as a Si source. As the aminosilane-based gas, for example, tris (dimethylamino) silane (SiH [N (CH ₃ ) ₂ ] ₃ , abbreviation: 3DMAS) gas can be used.

From the gas supply pipe 232b, a nitrogen (N) -containing gas is supplied as a reaction gas into the processing chamber 201 via the MFC 241b, the valve 243b, the nozzle 249b, and the buffer chamber 237. As the N-containing gas, for example, a hydrogen nitride-based gas can be used. The hydrogen nitride-based gas can be said to be a substance composed of only two elements, N and hydrogen (H), and acts as a nitride gas, that is, an N source. As the hydrogen nitride-based gas, for example, ammonia (NH ₃ ) gas can be used.

From the gas supply pipes 232c and 232d, nitrogen (N ₂ ) gas enters the processing chamber 201 via the MFC 241c, 241d, valves 243c, 243d, gas supply pipes 232a, 232b, nozzles 249a, 249b, and buffer chamber 237, respectively. Will be supplied. The N ₂ gas acts as a purge gas or a carrier gas. Further, the N ₂ gas supplied from the gas supply pipe 232d also acts as a reforming gas by being plasma-excited in step C described later.

The raw material gas supply system is mainly composed of the gas supply pipe 232a, the MFC 241a, and the valve 243a. The hydrogen nitride gas supply system is mainly composed of the gas supply pipe 232b, the MFC 241b, and the valve 243b. The nitrogen gas supply system is mainly composed of gas supply pipes 232c, 232d, MFC241c, 241d, and valves 243c, 243d.

Of the various supply systems described above, any or all of the supply systems may be configured as an integrated supply system 248 in which valves 243a to 243d, MFC 241a to 241d, and the like are integrated. The integrated supply system 248 is connected to each of the gas supply pipes 232a to 232d, and various gas supply operations into the gas supply pipes 232a to 232d, that is, the opening / closing operation of the valves 243a to 243d and the MFC 241a to 241d. The flow rate adjustment operation and the like are configured to be controlled by the controller 121 described later. The integrated supply system 248 is configured as an integrated or divided integrated unit, and can be attached to and detached from the gas supply pipes 232a to 232d in units of the integrated unit. It is configured so that maintenance, replacement, expansion, etc. can be performed on an integrated unit basis.

In the buffer chamber 237, two rod-shaped electrodes 269 and 270, which are composed of a conductor and have an elongated structure, stand up from the lower part to the upper part of the inner wall of the reaction tube 203 upward in the loading direction of the wafer 200. It is provided as such. The rod-shaped electrodes 269 and 270 are provided in parallel with the nozzle 249b, respectively. The rod-shaped electrodes 269 and 270 are each protected by being covered with an electrode protection tube 275 from the upper part to the lower part. One of the rod-shaped electrodes 269 and 270 is connected to the high frequency power supply 273 via the matching unit 272, and the other is connected to the ground which is the reference potential. By applying high frequency (RF) power between the high frequency power supply 273 and the rod electrodes 269 and 270, plasma is generated in the plasma generation region 224 between the rod electrodes 269 and 270. Mainly, the rod-shaped electrodes 269 and 270 and the electrode protection tube 275 constitute a plasma excitation section (activation mechanism) that excites (activates) the gas into a plasma state. The matching device 272 and the high frequency power supply 273 may be included in the plasma excitation section.

An exhaust pipe 231 that exhausts the atmosphere in the processing chamber 201 is connected below the side wall of the reaction pipe 203. The exhaust pipe 231 is provided via a pressure sensor 245 as a pressure detector (pressure detector) for detecting the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure regulator). , 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, By adjusting the valve opening degree based on the pressure information detected by the pressure sensor 245, the pressure in the processing chamber 201 can be adjusted. The exhaust system is mainly composed of an exhaust pipe 231, an APC valve 244, and a 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 palate body capable of airtightly closing 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. On the upper surface of the seal cap 219, an O-ring 220b is provided 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 200 by rotating the boat 217. The seal cap 219 is configured to be vertically lifted and lowered by a boat elevator 115 as a lifting mechanism installed outside the reaction tube 203. The boat elevator 115 is configured as a transport device (convey mechanism) for carrying in and out (transporting) the wafer 200 into and out of the processing chamber 201 by raising and lowering the seal cap 219. Further, below the manifold 209, a shutter 219s as a furnace palate body capable of airtightly closing the lower end opening of the manifold 209 is provided in a state where the seal cap 219 is lowered and the boat 217 is carried out from the processing chamber 201. There is. The shutter 219s is made of a metal material such as SUS and has a disk shape. On the upper surface of the shutter 219s, an O-ring 220c is provided as a seal member that contacts the lower end of the manifold 209. 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 a substrate support supports a plurality of wafers, for example, 25 to 200 wafers, in a horizontal position and vertically aligned with each other, that is, in a multi-stage manner. 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. By adjusting the degree of energization of the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature in the processing chamber 201 becomes a desired temperature distribution. The temperature sensor 263 is provided along the inner wall of the reaction tube 203.

As shown in FIG. 3, the controller 121, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. Has been done. The RAM 121b, the storage device 121c, and the I / O port 121d are configured so that data can be exchanged 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 device, a process recipe in which the procedure and conditions of the film forming process described later are described, and the like are readablely stored. The process recipes are combined so that the controller 121 can execute each procedure in the film forming process described later and obtain a predetermined result, and functions as a program. Hereinafter, process recipes, control programs, etc. are collectively referred to simply as programs. Further, the process recipe is also simply referred to as a recipe. When the word program is used in this specification, it may include only the recipe alone, may include only the control program alone, or may include 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 ports 121d include the above-mentioned MFCs 241a to 241d, valves 243a to 243d, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotation mechanism 267, boat elevator 115, shutter opening / closing mechanism 115s, It is connected to a matching device 272, a high frequency power supply 273, and the like.

The CPU 121a is configured to read and execute a control program from the storage device 121c and read a recipe from the storage device 121c in response to an input of an operation command from the input / output device 122 or the like. The CPU 121a adjusts the flow rate of various gases by the MFCs 241a to 241d, opens and closes the valves 243a to 243d, 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 vacuum pump 246, temperature adjustment operation of heater 207 based on temperature sensor 263, rotation and rotation speed adjustment operation of boat 217 by rotation mechanism 267, lifting operation of boat 217 by boat elevator 115, shutter opening and closing mechanism 115s It is configured to control the opening / closing operation of the shutter 219s, the impedance adjustment operation by the matching unit 272, the power supply to the high frequency power supply 273, and the like.

The controller 121 installs the above-mentioned program stored in an external storage device (for example, a magnetic disk such as an HDD, an optical disk such as a CD, a magneto-optical disk such as an MO, or a semiconductor memory such as a USB memory) 123 in a computer. Can be configured by 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 the present specification, it may include only the storage device 121c alone, it may include only the external storage device 123 alone, or it may include both of them. 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) Film formation processing A sequence example of forming a silicon nitride film (SiN film) on a wafer 200 as a substrate as one step of a manufacturing process of a semiconductor device using the above-mentioned substrate processing apparatus is shown in FIG. explain. In this embodiment, an example in which a substrate having a pattern including a trench formed on the surface of the wafer 200 as an example of a recess will be described. In the following description, the operation of each part of the substrate processing apparatus is controlled by the controller 121.

In the film formation sequence shown in FIG. 4,
Step A of forming the first layer by supplying 3DMAS gas as a raw material gas to the wafer 200 having a trench on the surface,
Step B of nitriding the first layer to form an NH-terminated second layer by supplying NH ₃ gas as a hydrogen nitride gas to the wafer 200.
By plasma-exciting and supplying N ₂ gas to the wafer 200, a part of the NH termination in the second layer is reformed to the N termination, and another part different from the above part of the NH termination is formed. Step C, which maintains the NH termination without modifying it to the N termination,
A SiN film is formed on the wafer 200 by repeating the non-simultaneous cycle.

In step C, the N termination rate at the upper part of the trench of the second layer is made higher than the N termination rate at the bottom of the trench of the second layer. In this case, by repeating the cycle, the thickness of the layer formed on the upper part of the trench (the layer formed by laminating the modified second layer) is changed to the thickness of the layer formed on the bottom of the trench (the modified second layer). It is possible to form a SiN film as a nitride film while making the thickness thicker than the thickness of the layer (layer formed by laminating the layers). As a result, the SiN film can be formed as a cap film on the upper part of the trench without embedding the inside of the trench with the SiN film (while maintaining the non-deposited area in the trench), and an air gap (hollow portion) can be formed in the trench. Can be formed.

Here, the effect of forming an air gap in the trench will be described.

In recent years, with the miniaturization and speeding up of semiconductor devices, an insulating film having a predetermined characteristic with a low capacitance is required in order to manufacture a device capable of achieving a desired performance. For example, the film (gate spacer, etc.) formed between the contact connecting the source / drain layer of the transistor and the wiring layer and the gate of the transistor has both electrical insulation and a low relative permittivity (k value). Is required. Generally, a silicon nitride film (k value 7.5 to 5) or the like is used as the insulating film, and a silicon oxide film (k value 3.9) is known as a film having a lower relative permittivity. As devices become finer and faster, it will be required to form a film that has both a lower relative permittivity (k value of less than 3.9) and insulating properties. Here, since the relative permittivity of air is 1, it is possible to achieve both low capacitance and insulating property by providing an air gap between layers for which insulation property is to be ensured. As a method of forming an air gap between layers, a method of selectively removing a film after performing a film forming process is also conceivable, but an apparatus for performing a film forming process as well as an apparatus for performing an etching process is required. Therefore, there are problems such as a decrease in production efficiency and an increase in production cost.

According to this embodiment, an air gap can be formed in the trench without performing etching treatment or the like, whereby an insulating film having a low capacitance can be formed with high productivity and low production cost. It becomes possible.

In the present specification, the film formation sequence shown in FIG. 4 may be shown as follows for convenience. The same notation will be used in the following description of the modified examples.

(3DMAS → NH ₃ ^* → N ₂ ^* ) × n ⇒ SiN

When the term "wafer" is used in the present specification, it may mean the wafer itself or a laminate of a wafer and a predetermined layer or film formed on the surface thereof. When the term "wafer surface" is used in the present specification, 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). After that, as shown in FIG. 1, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and carried into the processing chamber 201 (boat load). In this state, the seal cap 219 is in a state of sealing the lower end of the manifold 209 via the O-ring 220b.

(Pressure adjustment and temperature adjustment)
Vacuum exhaust (vacuum exhaust) is performed by the vacuum pump 246 so that the pressure (vacuum degree) in the processing chamber 201, that is, the space where the wafer 200 exists is desired. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure information. Further, the wafer 200 in the processing chamber 201 is heated by the heater 207 so as to have a desired processing temperature. At this time, the degree of energization of 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 mechanism 267 starts the rotation of the wafer 200. The operation of the vacuum pump 246 and the heating and rotation of the wafer 200 are all continuously performed at least until the processing of the wafer 200 is completed.

(Film formation step)
After that, the following three steps, that is, steps A to C, are sequentially performed.

[Step A]
In this step, 3DMAS gas is supplied to the wafer 200 in the processing chamber 201.

Specifically, the valve 243a is opened to allow 3DMAS gas to flow into the gas supply pipe 232a. The flow rate of the 3DMAS gas is adjusted by the MFC 241a, is supplied into the processing chamber 201 via the nozzle 249a, and is exhausted from the exhaust pipe 231. At this time, 3DMAS gas is supplied to the wafer 200. At this time, the valve 243 c, open the 243 d, the gas supply pipe 232c, may be supplied with _{N 2} gas into the 232 d. The flow rate of the N ₂ gas is adjusted by the MFC 241c and 241d, and the N ₂ gas is supplied into the processing chamber 201 via the nozzles 249a and 249b and the buffer chamber 237.

The processing conditions in this step are
3DMAS gas supply flow rate: 10 to 1000 sccm
N ₂ Gas supply flow rate (for each gas supply pipe): 0 to 10000 sccm
Each gas supply time: 1 to 100 seconds Processing temperature: 150 to 600 ° C, preferably 250 to 450 ° C
Processing pressure: 1-1333Pa
Is exemplified.

By supplying 3DMAS gas to the wafer 200 under the above conditions, a Si-containing layer containing an amino group is formed as the first layer on the outermost surface of the wafer 200. The Si-containing layer containing an amino group is formed by physically adsorbing 3DMAS on the outermost surface of the wafer 200, chemically adsorbing a substance in which a part of 3DMAS is decomposed, thermally decomposing 3DMAS, and the like. .. For example, the Si-containing layer containing an amino group is formed by chemically adsorbing Si on the outermost surface of the wafer 200 in 3DMAS in a state where a part of the ligand is desorbed. In addition, in this specification, a Si-containing layer containing an amino group is also simply referred to as a Si-containing layer.

After forming the first layer on the wafer 200, the valve 243a is closed to stop the supply of 3DMAS gas into the processing chamber 201. Then, the inside of the processing chamber 201 is evacuated, and the gas or the like remaining in the processing chamber 201 is removed from the inside of the processing chamber 201. At this time, the valve 243 c, open the 243 d, and supplies a _{N 2} gas into the processing chamber 201. The N ₂ gas acts as a purge gas.

As the raw material gas, in addition to 3DMAS gas, (diisopropylamino) silane (SiH ₃ N [CH (CH ₃ ) ₂ ] ₂ , abbreviated as DIPAS) gas, bis (diethylamino) silane (SiH ₂ [N (C ₂ H _{5) 5)} ) _{2] 2,} abbreviated: BDEAS) gas, bis (tertiary-butylamino) silane _{(SiH 2 [NH (C 4} H 9)] 2, abbreviated: BTBAS) gas, bis (diethyl piperidinophenyl) silane (SiH ₂ [NC ₅ H ₈ (C ₂ H ₅ ) ₂ ] ₂ , abbreviation: BDEPS) gas, tris (diethylamino) silane (SiH [N (C ₂ H ₅ ) ₂ ] ₃ , abbreviation: 3DEAS) gas, tetrakis (diethylamino) Silane (Si [N (C ₂ H ₅ ) ₂ ] ₄ , abbreviation: 4DEAS) gas, tetrakis (dimethylamino) silane (Si [N (CH ₃ ) ₂ ] ₄ , abbreviation: 4DMAS) gas, trisilylamine (N) Various aminosilane-based gases such as (SiH ₃ ) ₃ , abbreviation: TSA) gas can be used.

As the purge gas, in addition to the N ₂ gas, various rare gases such as Ar gas, He gas, Ne gas, and Xe gas can be used. This point is the same in steps B and C described later.

[Step B]
After the step A is completed, plasma-excited NH ₃ gas (NH ₃ ^* ) is supplied to the wafer 200 in the processing chamber 201, that is, the first layer formed on the wafer 200.

Specifically, while applying RF power between the rod-shaped electrodes 269 and 270, the opening and closing control of the valves 243b, 243c and 243d is performed in the same procedure as the opening and closing control of the valves 243a, 243c and 243d in step A. The flow rate of the NH ₃ gas is adjusted by the MFC 241b, is supplied into the processing chamber 201 via the nozzle 249b and the buffer chamber 237, and is exhausted from the exhaust pipe 231. At this time, the plasma-excited NH ₃ gas (NH ₃ ^* ) is supplied to the wafer 200. The NH ₃ gas is excited (activated) by plasma when passing through the buffer chamber 237, and at that time, active species such as NH ₃ ^* are generated, and the active species are supplied to the wafer 200. It will be. In the present specification, the plasma-excited NH ₃ gas is also referred to as NH ₃ ^* for convenience.

The processing conditions in this step are
NH ₃ gas supply flow rate: 100 to 10,000 sccm
NH ₃ Gas supply time: 1 to 100 seconds Processing pressure: 1 to 2000 Pa
RF power: 50-1000W
Is exemplified. Other processing conditions are the same as the processing conditions in step A. The processing conditions exemplified here are conditions that allow the active NH ₃ ^* to be evenly distributed not only to the upper part of the trench formed on the surface of the wafer 200 but also to the bottom of the trench and its surroundings.

By supplying NH ₃ ^* to the wafer 200 under the above conditions, at least a part of the first layer formed on the wafer 200 in step A is nitrided. By nitriding the first layer, a silicon nitride layer (SiN layer) containing Si and N is formed on the wafer 200 as the second layer. The surface of the second layer is nitrided by NH ₃ ^* to be in an NH-terminated state. FIG. 5A is a schematic view showing the surface state of the second layer formed on the upper part of the trench, and FIG. 5B is a schematic view showing the surface state of the second layer formed on the bottom of the trench. is there. As described above, under the treatment conditions in this step, the active NH ₃ ^* can be supplied to the entire surface of the first layer in an active state without being inactivated. As a result, the surface of the second layer obtained by nitriding the first layer can be evenly NH-terminated from the upper part of the trench to the entire bottom part. That is, in this step, the NH ₃ ^* concentration at the top of the trench is made equal to the NH ₃ ^* concentration at the bottom of the trench. Further, in this step, even if the active NH ₃ ^* is inactivated, NH ₃ ^* ratio of deactivation of the trench bottom is set to be equal to the NH ₃ ^* deactivation rate in the upper portion of the trench. When forming the second layer, impurities such as C and H contained in the first layer are extracted or desorbed from the first layer in the process of the nitriding reaction by NH ₃ ^*. Then, it is separated from the first layer.

After forming the second layer whose surface is NH-terminated on the wafer 200, the valve 243b is closed, the application of RF power between the rod-shaped electrodes 269 and 270 is stopped, and the NH ₃ into the processing chamber 201 is stopped. Stop the supply of ^* . Then, by the same processing procedure as in step A, the gas or the like remaining in the processing chamber 201 is removed from the processing chamber 201.

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

[Step C]
After the step B is completed, plasma-excited N ₂ gas (N ₂ ^* ) is supplied to the wafer 200 in the processing chamber 201, that is, the second layer whose surface is NH-terminated.

Specifically, while applying a RF power between the rod-shaped electrodes 269 and 270, opening the valve 243 d, flow the _{N 2} gas to the gas supply pipe 232 d. The flow rate of the N ₂ gas is adjusted by the MFC 241d, is supplied into the processing chamber 201 via the nozzle 249b and the buffer chamber 237, and is exhausted from the exhaust pipe 231. At this time, plasma-excited N ₂ gas (N ₂ ^* ) is supplied to the wafer 200. The N ₂ gas is excited (activated) by plasma when passing through the buffer chamber 237, and at that time, active species such as N ₂ ^* are generated, and these active species are supplied to the wafer 200. It will be. In the present specification, the plasma-excited N ₂ gas is also referred to as N ₂ ^* for convenience.

The processing conditions in this step are
Plasma-excited N ₂ gas supply flow rate: 10-5000 sccm
Plasma-excited N ₂ gas supply time: 1 to 90 seconds Processing pressure: 10 to 2666 Pa
RF power: 1-500W
Is exemplified. Other processing conditions are the same as the processing conditions in step A. The treatment conditions exemplified here are conditions that enable the active N ₂ ^* to be supplied mainly only to the upper part of the trench and its surroundings. That is, it is a condition that N ₂ ^* can be inactivated by the time it reaches the bottom of the trench and its periphery, and active N ₂ ^* can be supplied to these regions with little or no active N ₂ ^*. .. In other words, the treatment conditions exemplified here are such that the N ₂ ^* concentration at the top of the trench is higher than the N ₂ ^* concentration at the bottom of the trench, and the N ₂ ^* deactivation rate at the bottom of the trench is higher than that of the top of the trench. It is also a condition that becomes larger than N ₂ ^* deactivation rate in.

By supplying N ₂ ^* to the wafer 200 under the above conditions, it is possible to modify a part of the surface of the second layer formed on the wafer 200 in step B. That is, it is possible to desorb H from a part of the NH terminations existing on the surface of the second layer and modify (change) this to the N termination. As described above, under the treatment conditions in this step, the active N ₂ ^* is mainly supplied only to the upper part of the trench and its surroundings, and hardly or not to the bottom of the trench and its surroundings. Therefore, in the present embodiment, the above-mentioned reforming treatment is carried out mainly only in the upper part of the trench and its vicinity among the surfaces of the second layer formed on the wafer 200, and almost or not in the bottom of the trench and its vicinity. It is possible to prevent it from progressing. As a result, among the NH terminations existing on the surface of the second layer, some other NH terminations different from the above-mentioned some NH terminations that can be modified to N terminations are modified to N terminations. It is possible to maintain the NH termination without any problems. FIG. 5C is a schematic view showing a state in which a part of the NH termination in the second layer formed in the upper part of the trench is modified to the N termination, and FIG. 5D is formed in the bottom of the trench. It is a schematic diagram which shows the state which keeps the NH termination as it is without modifying the NH termination in the 2nd layer.

By performing this step, the N termination rate at the upper part of the trench of the second layer can be made higher than the N termination rate at the bottom of the trench of the second layer. Further, by performing this step, the NH termination rate at the bottom of the trench of the second layer can be made higher than the NH termination rate at the top of the trench of the second layer. That is, by performing this step, the N / NH termination ratio at the top of the trench of the second layer can be made larger than the N / NH termination ratio at the bottom of the trench of the second layer. The N termination rate referred to here is the amount of N termination (the number of N terminations existing on the surface) and the amount of NH termination (the number of NH terminations existing on the surface) per unit area of the surface of the second layer. It is the ratio of the N-terminated amount to the total amount of N-terminated amount [= N-terminated amount / (N-terminated amount + NH-terminated amount)]. Further, the NH termination rate referred to here is the ratio of the NH termination amount to the total amount of the N termination amount and the NH termination amount per unit area of the surface of the second layer [= NH termination amount / (N termination amount /). + NH termination amount)]. Further, the N / NH termination ratio referred to here is the ratio of the N termination amount to the NH termination amount [= N termination amount / NH termination amount] per unit area of the surface of the second layer.

The N-termination present on the surface of the second layer acts to promote the adsorption of Si contained in the 3DMAS gas to the surface of the second layer when performing step A in the next cycle. On the other hand, the NH termination existing on the surface of the second layer acts to suppress the adsorption of Si contained in the 3DMAS gas on the surface of the second layer when the step A is carried out in the next cycle. .. Therefore, by carrying out this step and making the N termination rate at the top of the trench of the second layer higher than the N termination rate at the bottom of the trench of the second layer, that is, the NH termination rate at the bottom of the trench of the second layer. By making it higher than the NH termination rate in the upper part of the trench of the second layer, when the step A is carried out in the next cycle, the surface of the second layer of Si contained in the 3DMAS gas is formed in the upper part of the trench and its surroundings. It is possible to promote adsorption to. On the other hand, at the bottom of the trench and its periphery, it is possible to suppress the adsorption of Si contained in 3DMAS gas on the surface of the second layer. FIG. 5 (e) is a schematic view showing how 3DMAS gas is supplied to the second layer (the second layer whose surface is modified to the N-terminal) formed in the upper part of the trench. FIG. f) is a schematic view showing how 3DMAS gas is supplied to the second layer (the second layer whose surface is maintained at the NH end) formed at the bottom of the trench.

That is, when the surface of the second layer is N-terminated, when a part of the Si—N bond contained in the 3DMAS gas is broken and a part of the ligand is eliminated, the Si contained in the 3DMAS gas is the second layer. Adsorbs to the N-terminal existing on the surface of. On the other hand, when the surface of the second layer is NH-terminated, even if a part of the Si—N bond contained in the 3DMAS gas is broken and a part of the ligand is desorbed, the NH-terminated surface of the second layer Unless the N—H bond is broken, Si contained in the 3DMAS gas will not be adsorbed on the surface of the second layer.

As a result, it is possible to promote the formation of the first layer at the upper part of the trench and its periphery, and suppress the formation of the first layer at the bottom of the trench and its periphery. In this case, the thickness of the first layer and the second layer formed on the upper part of the trench in the next cycle becomes thicker than the thickness of the first layer and the second layer formed on the bottom of the trench in the next cycle, respectively. That is, the thickness of the SiN layer formed on the upper part of the trench per cycle is thicker than the thickness of the SiN layer formed on the bottom of the trench per cycle. As a result, it is possible to form a SiN film as a cap film on the upper part of the trench without embedding the inside of the trench with the SiN film, that is, while holding a desired non-deposited area in the trench, and an air gap in the trench. Can be formed.

Further, in this step, the N termination rate at the upper part of the trench of the second layer is made higher than the NH termination rate at the upper part of the trench of the second layer by optimizing the processing conditions when supplying N ₂ ^*. Is possible. Further, the NH termination rate at the bottom of the trench of the second layer can be made higher than the N termination rate at the bottom of the trench of the second layer. In this case, in step A in the next cycle, the above-mentioned effect of promoting the formation of the first layer on the upper part of the trench and suppressing the formation of the first layer on the bottom of the trench is more reliably obtained. Will be able to. That is, it is possible to more reliably promote the growth of the cap film in the upper part of the trench, reliably hold the desired non-deposited region in the trench, and form an appropriate air gap.

In order to obtain the effects described here, active N ₂ ^* is mainly supplied only to the upper part of the trench and its surroundings, and hardly or at all to the bottom of the trench and its surroundings (not reachable). , It is important to perform step C. For example, if the processing pressure in step C is made larger than the processing pressure in step B, the lifetime of active N ₂ ^* can be appropriately shortened, and the effects described here can be surely obtained. Will be able to. Further, for example, even if the RF power in step C is made smaller than the RF power in step B, the lifetime of the active N ₂ ^* can be appropriately shortened, and the effect described here can be surely shortened. You will be able to obtain it. Further, for example, if the supply time of N ₂ ^* in step C is made shorter than the supply time of NH ₃ ^* in step B, the probability of reaching the bottom of the trench of active N ₂ ^* and its surroundings is reduced. This will ensure that the effects described here are obtained.

After performing the necessary modification treatment on a part of the surface of the second layer, the valve 243d is closed, the application of RF power between the rod-shaped electrodes 269 and 270 is stopped, and the inside of the processing chamber 201 is entered. N ₂ ^* supply will be stopped. Then, by the same processing procedure as in step A, the gas or the like remaining in the processing chamber 201 is removed from the processing chamber 201.

[Performed a predetermined number of times]
By performing the above-mentioned steps A to C non-simultaneously, that is, alternately performing the cycles without synchronization a predetermined number of times (n times, n is an integer of 1 or more), FIGS. 6 (a) to 6 (d) can be obtained. As shown, the SiN film 300 is formed on the pattern including the trench formed on the surface of the wafer 200, and at that time, the cap film by the SiN film 300 is formed on the upper part of the trench without embedding the inside of the trench by the SiN film 300. It becomes possible to form. As a result, as shown in FIG. 6D, an air gap 400 is formed in the trench.

(Afterpurge and return to atmospheric pressure)
After the film forming step is completed, N ₂ gas as a purge gas is supplied from each of the gas supply pipes 232c and 232d into the processing chamber 201 and exhausted from the exhaust pipe 231. As a result, the inside of the treatment chamber 201 is purged, and the gas and reaction by-products remaining in the treatment chamber 201 are removed from the inside of the treatment chamber 201 (after-purge). After that, the atmosphere in the treatment chamber 201 is replaced with the inert gas (replacement of the inert gas), and the pressure in the treatment chamber 201 is restored to normal pressure (return to atmospheric pressure).

(Boat unloading and wafer discharge)
The boat elevator 115 lowers the seal cap 219 to open the lower end of the manifold 209. Then, the processed wafer 200 is carried out (boat unloading) from the lower end of the manifold 209 to the outside of the reaction tube 203 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 the present embodiment According to the above-described embodiment, one or more of the following effects can be obtained.

(A) By performing step C after forming the second layer whose surface is NH-terminated, the N termination rate at the top of the trench of the second layer is made higher than the N termination rate at the bottom of the trench of the second layer. It becomes possible. As a result, the growth of the SiN layer in the upper part of the trench can be promoted, and the SiN film can be formed as a cap film in the upper part of the trench without embedding the inside of the trench with the SiN film. As a result, it becomes possible to form an air gap (hollow portion) in the trench.

(B) By performing step C after forming the second layer whose surface is NH-terminated, the NH termination rate at the bottom of the trench of the second layer is made higher than the NH termination rate at the upper part of the trench of the second layer. It becomes possible. As a result, the growth of the SiN layer at the bottom of the trench can be suppressed, and when a SiN film is formed as a cap film on the upper part of the trench, a desired non-deposited region can be held in the trench, and the inside of the trench can be maintained. Can be prevented from being embedded by the SiN film. As a result, it is possible to form an air gap in the trench.

(C) After forming the second layer whose surface is NH-terminated, step C is performed to obtain the N / NH termination ratio at the top of the trench of the second layer and the N / NH termination ratio at the bottom of the trench of the second layer. Can be made larger than. As a result, it is possible to surely promote the growth of the cap film in the upper part of the trench and to form an air gap in the trench without embedding the inside of the trench with the SiN film.

(D) By performing step C after forming the second layer whose surface is NH-terminated, the N termination rate at the upper part of the trench of the second layer is made higher than the NH termination rate at the upper part of the trench of the second layer. It becomes possible. Further, the NH termination rate at the bottom of the trench of the second layer can be made higher than the N termination rate at the bottom of the trench of the second layer. As a result, it is possible to surely promote the growth of the cap film in the upper part of the trench and to form an air gap in the trench without embedding the inside of the trench with the SiN film.

(E) the above-described effect, and when using an aminosilane-based gas of the material gas Cl-free non 3DMAS gas as (Cl free), even in the case of using NH ₃ hydronitrogen based gas other than the gas as the reaction gas, similar Can be obtained.

(4) Modification example This embodiment can be modified as the following modification example. Moreover, these modified examples can be arbitrarily combined.

(Modification example 1)
For example, as a film-forming sequence shown below, in step B, rather than supplying the NH ₃ gas by plasma excitation may be supplied by thermal excitation.

(3DMAS → NH ₃ → N ₂ ^* ) × n ⇒ SiN

(Modification 2)
Further, for example, the order of flowing the gas may be changed as in the film forming sequence shown in FIG. 7 and the following.

(NH ₃ ^* → N ₂ ^* → 3DMAS) × n ⇒ SiN

(Modification 3)
Further, for example, the order of flowing the gas may be changed as in the film forming sequence shown below.

(N ₂ ^* → 3DMAS → NH ₃ ^* ) × n ⇒ SiN

In the cases of Modifications 1 to 3, the same effect as the film formation sequence shown in FIG. 4 can be obtained. That is, it is possible to form a SiN film as a cap film on the upper part of the trench while suppressing embedding in the trench by the SiN film, and it is possible to form an air gap in the trench. Also in these modified examples, the processing pressure in step C is made larger than the processing pressure in step B, the RF power in step C is made smaller than the RF power in step B, and the supply time of N ₂ ^* in step C is increased. By making the time shorter than the supply time of NH ₃ gas in step B, this effect can be obtained more reliably. According to the second modification, it is possible to promote the adsorption of Si to the upper part of the trench and its periphery from the first cycle, and to suppress the adsorption of Si to the bottom of the trench and its periphery from the first cycle. Therefore, this effect can be obtained more efficiently.

(Modification example 4)
For example, when the cycle is repeated a plurality of times, the processing pressure in step C may be set to be higher than the processing pressure in step B, and may be gradually reduced as the cycle is repeated.

Further, for example, when the cycle is repeated a plurality of times, the RF power in step C may be set to be smaller than the RF power in step B, and may be gradually increased as the cycle is repeated.

Further, for example, when the cycle is repeated a plurality of times, the supply time of N ₂ ^* in step C may be shorter than the supply time of NH ₃ ^* in step B, and may be gradually lengthened as the cycle is repeated.

Further, for example, when the cycle is repeated a predetermined number of times, step C may be carried out only in the initial to middle stage, and step C may not be carried out in the middle to final stage.

Also in these cases, it is possible to form a cap film on the upper part of the trench and form an air gap in the trench as in the film forming sequence shown in FIG. Further, when the cycle is repeated a plurality of times, the film forming rate can be increased from the initial stage to the final stage, and the productivity of the film forming process can be improved.

<Other embodiments>
The embodiment of the present invention has been specifically described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof.

For example, the present invention is suitably applied not only when forming a metalloid nitride film containing a metalloid element such as silicon as a main element, but also when forming a metalloid nitride film containing a metal element as a main element. be able to. For example, the present invention uses a raw material such as tris (diethylamino) aluminum (Al [N (C ₂ H ₅ ) ₂ ] ₃ , abbreviated as TDEAA) as shown below, and uses an aluminum nitride film (AlN) as an insulating film. It can also be suitably applied when forming a film).

(TDEAA → NH ₃ ^* → N ₂ ^* ) × n ⇒ AlN

The processing procedure and processing conditions for the film forming process at this time can be the same as the processing procedures and processing conditions for the above-described embodiments and modifications. Also in these cases, the same effects as those of the above-described embodiments and modifications can be obtained.

Further, for example, the present invention can be suitably applied to the case where the wafer 200 uses a substrate having a pattern including recesses such as holes as well as recesses such as trenches formed on the surface thereof. In this case, the "trench" in the above description may be replaced with a "hole". Also in this case, the same effect as that of the above-described embodiment or modification can be obtained.

It is preferable that the recipes used for the substrate processing are individually prepared according to the processing content and stored in the storage device 121c via a telecommunication line or an external storage device 123. Then, when starting the substrate processing, it is preferable that the CPU 121a appropriately selects an appropriate recipe from the 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. In addition, the burden on the operator can be reduced, and the process can be started quickly while avoiding operation mistakes.

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

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

Even when these substrate processing devices are used, the film can be formed under the same processing procedures and conditions as those in the above-described embodiments and modifications, and the same effects as these can be obtained.

In addition, the above-described embodiments and modifications can be used in combination as appropriate. The processing procedure and processing conditions at this time can be, for example, the same as the processing procedure and processing conditions of the above-described embodiment.

200 wafers (board)

Claims (15)

(A) A step of forming a first layer by supplying a raw material gas containing an amino group to a substrate having a recess on the surface.
(B) A step of nitriding the first layer by supplying a hydrogen nitride-based gas to the substrate to form an NH-terminated second layer.
(C) By plasma-exciting and supplying nitrogen gas to the substrate, a part of the NH terminal in the second layer is modified to an N terminal, which is different from the part of the NH terminal. The process of maintaining the NH terminal without modifying a part of the N terminal, and
By repeating the cycle of performing the above non-simultaneously, a step of forming a nitride film on the substrate is provided.
(C), a method for manufacturing a semiconductor device, wherein the N termination rate at the upper part of the recess of the second layer is higher than the N termination rate at the bottom of the recess of the second layer. The method for manufacturing a semiconductor device according to claim 1, wherein in (c), the NH termination rate at the bottom of the recess of the second layer is higher than the NH termination rate at the top of the recess of the second layer. The semiconductor device according to claim 1, wherein in (c), the N / NH termination ratio at the upper part of the recess of the second layer is made larger than the N / NH termination ratio at the bottom of the recess of the second layer. Production method. In (c), the N termination rate at the upper part of the recess of the second layer is made higher than the NH termination rate at the upper part of the recess of the second layer, and the NH termination at the bottom of the recess of the second layer. The method for manufacturing a semiconductor device according to claim 1, wherein the rate is higher than the N termination rate at the bottom of the recess of the second layer. The method for manufacturing a semiconductor device according to claim 1, wherein (c) promotes adsorption of an element contained in the raw material gas to the upper portion of the recess in (a) of the next cycle. The method for manufacturing a semiconductor device according to claim 1, wherein the method (c) suppresses the adsorption of the element contained in the raw material gas to the bottom of the recess in the next cycle (a). In (b), the hydrogen nitride-based gas is plasma-excited and supplied.
The method for manufacturing a semiconductor device according to claim 1, wherein the pressure in the space where the substrate exists in (c) is made larger than the pressure in the space where the substrate exists in (b). In (b), the hydrogen nitride-based gas is plasma-excited and supplied.
The method for manufacturing a semiconductor device according to claim 1, wherein the electric power for plasma-exciting the nitrogen gas in (c) is smaller than the electric power for plasma-exciting the hydrogen nitride-based gas in (b). In (b), the hydrogen nitride-based gas is plasma-excited or thermally excited and supplied.
The semiconductor device according to claim 1, wherein the time for plasma-exciting and supplying the nitrogen gas in (c) is shorter than the time for plasma-exciting or thermally exciting the hydrogen nitride-based gas in (b). Production method. According to claim 1, the nitride film is formed by repeating the cycle so that the thickness of the layer formed on the upper portion of the recess is made thicker than the thickness of the layer formed on the bottom of the recess. The method for manufacturing a semiconductor device according to the description. By repeating the cycle, the nitride film is formed so that the thickness of the layer formed on the upper part of the recess is thicker than the thickness of the layer formed on the bottom of the recess. The method for manufacturing a semiconductor device according to claim 1, wherein the nitride film is formed as a cap film on the upper portion of the recess without embedding the inside of the recess with the nitride film, and an air gap is formed in the recess. The method for manufacturing a semiconductor device according to any one of claims 1 to 11, wherein the raw material gas does not contain chlorine. The method for manufacturing a semiconductor device according to any one of claims 1 to 11, wherein the raw material gas contains aminosilane gas. A processing room where processing is performed on the substrate, and
A raw material gas supply system that supplies a raw material gas containing an amino group to the substrate in the processing chamber,
A hydrogen nitride gas supply system that supplies hydrogen nitride gas to the substrate in the processing chamber, and a hydrogen nitride gas supply system.
A nitrogen gas supply system that supplies nitrogen gas to the substrate in the processing chamber,
A plasma excitation part that excites gas by plasma,
In the processing chamber, (a) a process of forming the first layer by supplying the raw material gas to a substrate having a recess on the surface, and (b) supplying the hydrogen nitride-based gas to the substrate. By doing so, the first layer is nitrided to form an NH-terminated second layer, and (c) the nitrogen gas is plasma-excited and supplied to the substrate to supply the second layer. A process of modifying a part of the NH termination in the layer to N termination and maintaining the other part different from the NH termination to N termination without modifying it to N termination. By repeating the cycle performed at the same time, a process of forming a nitride film on the substrate is performed, and in (c), the N termination rate at the upper part of the recess of the second layer is set to that of the recess of the second layer. A control unit configured to control the raw material gas supply system, the hydrogen nitride gas supply system, the nitrogen gas supply system, and the plasma excitation unit so as to be higher than the N termination rate at the bottom.
A substrate processing apparatus having. In the processing room of the substrate processing equipment
(A) A procedure for forming the first layer by supplying a raw material gas containing an amino group to a substrate having recesses on the surface.
(B) A procedure for nitriding the first layer by supplying a hydrogen nitride-based gas to the substrate to form an NH-terminated second layer.
(C) By plasma-exciting and supplying nitrogen gas to the substrate, a part of the NH termination in the second layer is modified to an N termination, which is different from the part of the NH termination. The procedure for maintaining the NH termination without modifying a part of the N termination, and
By repeating the non-simultaneous cycle of forming a nitride film on the substrate,
In (c), the procedure for increasing the N termination rate at the upper part of the recess of the second layer to be higher than the N termination rate at the bottom of the recess of the second layer.
A program that causes the board processing apparatus to execute the above.

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