阅读说明：本技术 半导体器件的制造方法、衬底处理装置及记录介质 (Method for manufacturing semiconductor device, substrate processing apparatus, and recording medium ) 是由 西田圭吾 尾崎贵志 佐佐木隆史 于 2018-09-21 设计创作，主要内容包括：提供提高在衬底表面形成的氧化膜的面内膜厚分布的控制性的技术。具有下述工序：第1工序,向处于低于大气压的第1压力下并被加热了的衬底供给含氧气体和含氢气体,对所述衬底的表面进行氧化并形成第1氧化层；以及第2工序,向处于与所述第1压力不同且低于大气压的第2压力下并被加热了的所述衬底供给所述含氧气体和所述含氢气体,对形成有所述第1氧化层的所述衬底的表面进行氧化并形成第2氧化层。(Provided is a technique for improving controllability of in-plane film thickness distribution of an oxide film formed on a substrate surface. Comprises the following steps: a 1 st step of supplying an oxygen-containing gas and a hydrogen-containing gas to a heated substrate at a 1 st pressure lower than atmospheric pressure to oxidize a surface of the substrate and form a 1 st oxide layer; and a 2 nd step of supplying the oxygen-containing gas and the hydrogen-containing gas to the substrate heated at a 2 nd pressure which is different from the 1 st pressure and lower than the atmospheric pressure, and oxidizing a surface of the substrate on which the 1 st oxide layer is formed to form a 2 nd oxide layer.)

1. A method for manufacturing a semiconductor device, comprising:

a 1 st step of supplying an oxygen-containing gas and a hydrogen-containing gas to the heated substrate at a 1 st pressure lower than atmospheric pressure to oxidize a surface of the substrate and form a 1 st oxide layer; and

and a 2 nd step of supplying the oxygen-containing gas and the hydrogen-containing gas to the substrate heated at a 2 nd pressure which is different from the 1 st pressure and lower than atmospheric pressure, and oxidizing a surface of the substrate on which the 1 st oxide layer is formed to form a 2 nd oxide layer.

2. The method for manufacturing a semiconductor device according to claim 1, wherein in the 1 st step and the 2 nd step, the oxygen-containing gas and the hydrogen-containing gas are supplied from an outer periphery of the substrate toward a center.

3. The method for manufacturing a semiconductor device according to claim 2, wherein in the 1 st step and the 2 nd step, a surface of the substrate is oxidized while being rotated.

4. The method for manufacturing a semiconductor device according to claim 3, wherein the 1 st pressure is lower than the 2 nd pressure,

the 1 st pressure is set so that a rate of oxidizing the surface of the substrate at the center of the substrate in the 1 st process is larger than near the outer periphery of the substrate.

5. The manufacturing method of the semiconductor device according to claim 4, wherein the 2 nd pressure is set so that:

in the 2 nd step, a rate of oxidizing the surface of the substrate on which the 1 st oxide layer is formed at the center of the substrate is smaller than that in the vicinity of the outer periphery of the substrate.

6. The method for manufacturing a semiconductor device according to claim 1, further comprising an initial step of supplying an oxygen-containing gas to the substrate to oxidize the surface of the substrate and form an initial oxide layer, before the 1 st step.

7. The method for manufacturing a semiconductor device according to claim 6, wherein a rate of forming the initial oxide layer in the initial process is lower than a rate of forming the 1 st oxide layer in the 1 st process.

8. The method for manufacturing a semiconductor device according to claim 6, wherein the oxygen-containing gas supplied in the initial step is oxygen and does not contain hydrogen.

9. The method for manufacturing a semiconductor device according to claim 1, wherein an inert gas nozzle is further provided, the inert gas nozzle being different from one or more nozzles configured to supply the oxygen-containing gas and the hydrogen-containing gas to the substrate, the inert gas nozzle being configured to supply an inert gas to the substrate.

10. The method for manufacturing a semiconductor device according to claim 9, wherein a plurality of the inert gas nozzles are provided.

11. The method for manufacturing a semiconductor device according to claim 1, wherein a hydrogen gas nozzle is further provided, the hydrogen gas nozzle being different from one or more nozzles configured to supply the oxygen-containing gas and the hydrogen-containing gas to the substrate, the hydrogen gas nozzle being configured to supply hydrogen gas to the substrate.

12. The method for manufacturing a semiconductor device according to claim 11, wherein a plurality of the hydrogen gas nozzles are provided.

13. The method for manufacturing a semiconductor device according to claim 1, wherein in the 1 st step and the 2 nd step, an inert gas is supplied to the substrate,

changing the supply flow rate of the inert gas to the substrate in the 1 st step and the 2 nd step.

14. The method for manufacturing a semiconductor device according to claim 1, wherein hydrogen gas is supplied to the substrate in the 1 st step and the 2 nd step,

changing the supply flow rate of the hydrogen gas to the substrate in the 1 st step and the 2 nd step.

15. A substrate processing apparatus, comprising:

a processing container for accommodating a substrate;

an oxygen-containing gas supply system configured to supply an oxygen-containing gas into the processing container;

a hydrogen-containing gas supply system configured to supply a hydrogen-containing gas into the processing container;

a heater for heating the substrate accommodated in the processing container;

an exhaust system configured to exhaust the inside of the processing container; and

a control unit configured to control the oxygen-containing gas supply system, the hydrogen-containing gas supply system, the heater, and the exhaust system to perform the following 1 st process and the following 2 nd process:

a 1 st process of heating the substrate to a 1 st pressure lower than atmospheric pressure in the processing container, supplying the oxygen-containing gas and the hydrogen-containing gas to the heated substrate, and oxidizing a surface of the substrate to form a 1 st oxide layer;

and a 2 nd process of forming a 2 nd oxide layer by supplying the oxygen-containing gas and the hydrogen-containing gas to the heated substrate to oxidize a surface of the substrate on which the 1 st oxide layer is formed, the inside of the process container being set to a 2 nd pressure which is different from the 1 st pressure and lower than atmospheric pressure.

16. A computer-readable recording medium having recorded thereon a program for causing a substrate processing apparatus to execute:

a 1 st step of supplying an oxygen-containing gas and a hydrogen-containing gas to a heated substrate stored in a processing chamber of the substrate processing apparatus and at a 1 st pressure lower than atmospheric pressure to oxidize a surface of the substrate to form a 1 st oxide layer,

and a 2 nd step of supplying the oxygen-containing gas and the hydrogen-containing gas to the substrate at a 2 nd pressure which is different from the 1 st pressure and lower than atmospheric pressure, and oxidizing a surface of the substrate on which the 1 st oxide layer is formed to form a 2 nd oxide layer.

Technical Field

The invention relates to a method for manufacturing a semiconductor device, a substrate processing apparatus and a recording medium.

Background

As one step of a manufacturing process of a semiconductor device, a step of supplying an oxygen-containing gas to a substrate in a processing chamber and forming an oxide film on the surface of the substrate is performed (for example, see patent documents 1 and 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5325363

Patent document 2: japanese patent No. 6199570

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional technique, it is difficult to make the in-plane film thickness distribution of the oxide film formed on the substrate surface uniform.

Means for solving the problems

One aspect of the present invention provides a technique including the steps of:

a 1 st step of supplying an oxygen-containing gas and a hydrogen-containing gas to the heated substrate at a 1 st pressure lower than atmospheric pressure to oxidize a surface of the substrate and form a 1 st oxide layer; and

and a 2 nd step of supplying the oxygen-containing gas and the hydrogen-containing gas to the substrate heated at a 2 nd pressure which is different from the 1 st pressure and lower than atmospheric pressure, and oxidizing a surface of the substrate on which the 1 st oxide layer is formed to form a 2 nd oxide layer.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, controllability of an in-plane film thickness distribution of an oxide film formed on a substrate surface can be improved.

Drawings

Fig. 1 is a schematic vertical sectional view showing a processing furnace of a substrate processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the treatment furnace shown in FIG. 1 taken along line A-A.

Fig. 3 is a schematic configuration diagram of a controller of a substrate processing apparatus according to an embodiment of the present invention, and a control system of the controller is shown as a block diagram.

Fig. 4 is a diagram showing a gas supply timing in an embodiment of the present invention.

Fig. 5 (a) is a diagram showing a model diagram of an SiO layer formed in an initial step, (B) is a diagram showing a model diagram of an SiO layer formed in a first step, and (C) is a diagram showing a model diagram of an SiO layer formed in a second step.

FIG. 6 is a schematic view showing a structure consisting of H₂Gas and O₂Graph of the relationship between the time of the oxidation treatment by gas and the thickness of the film formed.

FIG. 7 is a view showing H₂Gas and O₂H in gas mixture₂Graph of the relationship between the ratio of gas and the film formation rate.

Fig. 8 is a graph showing the pressure dependence of in-plane uniformity.

Fig. 9 (a) is a graph showing the film thickness distribution of the SiO layer formed on the surface of the wafer placed on the upper portion of the boat in the present embodiment, (B) is a graph showing the film thickness distribution of the SiO layer formed on the surface of the wafer placed on the central portion of the boat in the present embodiment, and (C) is a graph showing the film thickness distribution of the SiO layer formed on the surface of the wafer placed on the lower portion of the boat in the present embodiment; (D) the film thickness distribution of the SiO layer formed on the surface of the wafer placed on the boat in the comparative example is shown, (E) the film thickness distribution of the SiO layer formed on the surface of the wafer placed on the center portion of the boat in the comparative example is shown, and (F) the film thickness distribution of the SiO layer formed on the surface of the wafer placed on the lower portion of the boat in the comparative example is shown.

Detailed Description

Next, preferred embodiments of the present invention will be described.

The following description will be made with reference to fig. 1 to 4. The substrate processing apparatus 10 is an example of an apparatus used in a manufacturing process of a semiconductor device.

(1) Constitution of substrate processing apparatus

Fig. 1 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus 10 preferably used in the present embodiment for carrying out the method of manufacturing a semiconductor device according to the present embodiment, and a portion of the processing furnace 202 is shown in a vertical sectional view. Fig. 2 is a schematic configuration diagram of a vertical type treatment furnace preferably used in the present embodiment, and a part of the treatment furnace 202 is shown in a sectional view along line a-a of fig. 1.

As shown in fig. 1, the processing furnace 202 has a heater 207 as a heating unit (heating mechanism). The heater 207 has a cylindrical shape and is vertically mounted by being supported by a heater base (not shown). As described later, the heater 207 also functions as an activation mechanism for activating gas by heat.

The reaction tube 203 is disposed inside the heater 207 in a concentric manner with the heater 207. The reaction tube 203 is made of, for example, quartz (SiO)₂) Or a heat-resistant material such as silicon carbide (SiC), and is formed into a cylindrical shape having a closed upper end and an open lower end. A processing chamber 201 is formed in the hollow of the reaction tube 203. The processing chamber 201 is configured to accommodate a wafer 200 as a substrate. The process for the wafer 200 is performed in the process chamber 201.

In the processing chamber 201, a 1 st nozzle 249a, a 2 nd nozzle 249b, a 1 st auxiliary nozzle 249c, a 2 nd auxiliary nozzle 249d, and a 3 rd auxiliary nozzle 249e are provided so as to penetrate through a lower side wall of the reaction tube 203. The 1 st nozzle 249a and the 2 nd nozzle 249b are connected to the 1 st gas supply pipe 232a and the 2 nd gas supply pipe 232b, respectively. The 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e are connected to the 3 rd gas supply pipe 232c, the 4 th gas supply pipe 232d, and the 5 th gas supply pipe 232e, respectively.

The 1 st nozzle 249a, the 2 nd nozzle 249b, the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e are each formed as an L-shaped nozzle, and a horizontal portion thereof is provided so as to penetrate through a lower side wall of the reaction tube 203. The vertical portions of the 1 st nozzle 249a, the 2 nd nozzle 249b and the 1 st auxiliary nozzle 249c are provided inside a groove-shaped preliminary chamber 201a formed to protrude outward in the radial direction of the reaction tube 203 and extend in the vertical direction, and are provided upward (upward in the arrangement direction of the wafers 200) along the inner wall of the reaction tube 203 in the preliminary chamber 201 a. The vertical portion of the 1 st auxiliary nozzle 249c is provided adjacent to the 1 st nozzle 249a and the 2 nd nozzle 249 b. The vertical portions of the 2 nd auxiliary nozzle 249d and the 3 rd auxiliary nozzle 249e are provided inside the preliminary chamber 201b having a groove shape formed to protrude outward in the radial direction of the reaction tube 203 and extend in the vertical direction, and are provided upward along the inner wall of the reaction tube 203 in the preliminary chamber 201b, similarly to the preliminary chamber 201 a. The vertical portions of the 2 nd auxiliary nozzle 249d and the 3 rd auxiliary nozzle 249e are disposed adjacent to each other.

The 1 st nozzle 249a and the 2 nd nozzle 249b are provided to extend from a lower region of the process chamber 201 to an upper region of the process chamber 201. A plurality of gas supply holes 250a and 250b are provided in the 1 st nozzle 249a and the 2 nd nozzle 249b, respectively, at positions facing the wafers 200 and at a height from the lower portion to the upper portion of the boat 217, and in a range from the lower portion to the upper portion of the reaction tube 203. The gas supply holes 250a, 250b have the same opening area as each other and are arranged at the same opening interval.

The 1 st auxiliary nozzle 249c is provided to extend from a lower region of the process chamber 201 to an upper region of the process chamber 201. The 1 st auxiliary nozzle 249c is provided with a plurality of gas supply holes 250c only at positions corresponding to the wafers 200 arranged in the upper region of the boat 217 and at a height position above the 1 st auxiliary nozzle 249c in the extending direction. The gas supply holes 250c have the same opening area as each other and are disposed at the same opening interval. Therefore, the gas supplied from the gas supply hole 250c of the 1 st auxiliary nozzle 249c into the process chamber 201 is supplied to the wafers 200 accommodated in the upper region of the boat 217.

The 2 nd auxiliary nozzle 249d is provided to extend from a lower region of the process chamber 201 to a middle region of the process chamber 201. The 2 nd sub-nozzle 249d is provided with a plurality of gas supply holes 250d only at positions facing the wafers 200 arranged in the middle region of the wafer boat 217, below the gas supply holes 250c of the 1 st sub-nozzle 249c, and above the gas supply holes 250e of the 3 rd sub-nozzle 249e, which will be described later. The gas supply holes 250d have the same opening area as each other and are disposed at the same opening interval. Therefore, the gas supplied from the gas supply hole 250d of the 2 nd auxiliary nozzle 249d into the process chamber 201 is supplied to the wafers 200 accommodated in the middle region of the boat 217.

The 3 rd auxiliary nozzle 249e is provided to extend to a lower region of the process chamber 201. The 3 rd auxiliary nozzle 249e is provided with a plurality of gas supply holes 250e only at positions facing the wafers 200 arranged in the lower region of the wafer boat 217 and at a height position below the gas supply holes 250d of the 2 nd auxiliary nozzle 249 d. The gas supply holes 250e have the same opening area as each other and are arranged at the same opening interval. Therefore, the gas supplied into the process chamber 201 from the gas supply hole 250e of the 3 rd auxiliary nozzle 249e is supplied to the wafers 200 accommodated in the lower region of the boat 217.

That is, the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e have different lengths (heights) in the process chamber 201, and at least some of the gas supply holes 250c to 250e provided in the respective nozzles have different positions in the height direction (positions in the extending direction of the nozzles).

The 1 st, 2 nd, 3 rd, 4 th and 5 th gas supply pipes 232a, 232b, 232c, 232d and 232e are provided with Mass Flow Controllers (MFCs) 241a to 241e as flow rate controllers (flow rate control units) and valves 243a to 243e as on-off valves, respectively, and the 1 st, 2 nd, 3 rd, 4 th and 5 th inert gas supply pipes 232f, 232g, 232h, 232i and 232j are connected to the gas supply pipes 232a, 232b, 232c, 232d and 232e, respectively. MFCs 241f to 241j and valves 243f to 243j are provided in the 1 st inert gas supply pipe 232f, the 2 nd inert gas supply pipe 232g, the 3 rd inert gas supply pipe 232h, the 4 th inert gas supply pipe 232i, and the 5 th inert gas supply pipe 232j, respectively.

The 1 st gas supply system is mainly constituted by the 1 st gas supply pipe 232a, the MFC241a, and the valve 243 a. It is also conceivable to include the 1 st nozzle 249a in the 1 st gas supply system. The 1 st inert gas supply system is mainly constituted by the 1 st inert gas supply pipe 232f, the MFC241f, and the valve 243 f.

The 2 nd gas supply system is mainly constituted by the 2 nd gas supply pipe 232b, the MFC241b, and the valve 243 b. It is also conceivable to include the 2 nd nozzle 249b in the 2 nd gas supply system. The 2 nd inert gas supply system is mainly constituted by the 2 nd inert gas supply pipe 232g, the MFC241g, and the valve 243 g.

The 1 st auxiliary gas supply system is mainly constituted by the 3 rd gas supply pipe 232c, the MFC241c, and the valve 243 c. It is also conceivable to include the 1 st auxiliary nozzle 249c in the 1 st auxiliary gas supply system. The 3 rd inert gas supply system is mainly constituted by the 3 rd inert gas supply pipe 232h, the MFC241h, and the valve 243 h.

The 4 th gas supply pipe 232d, the MFC241d, and the valve 243d mainly constitute a 2 nd auxiliary gas supply system. It is also conceivable to include the 2 nd auxiliary nozzle 249d in the 2 nd auxiliary gas supply system. The 4 th inert gas supply line 232i, the MFC241i, and the valve 243i mainly constitute a 4 th inert gas supply system.

The 5 th gas supply pipe 232e, the MFC241e, and the valve 243e mainly constitute a 3 rd auxiliary gas supply system. It is also conceivable to include the 3 rd auxiliary nozzle 249e in the 3 rd auxiliary gas supply system. The 5 th inert gas supply line 232j, the MFC241j, and the valve 243j mainly constitute a 5 th inert gas supply system. The 1 st to 5 th inert gas supply systems also function as purge gas supply systems, respectively.

As an oxidizing gas (oxidizing gas), an oxygen-containing gas, for example, oxygen (O), is supplied into the processing chamber 201 from the 1 st gas supply pipe 232a through the MFC241a, the valve 243a, and the 1 st nozzle 249a₂) A gas. That is, the 1 st gas supply system is configured as an oxygen-containing gas supply system that supplies an oxygen-containing gas into the processing chamber 201. At the same time, the inert gas may be supplied from the 1 st inert gas supply pipe 232f into the 1 st gas supply pipe 232 a.

As a reducing gas (reducing gas), a hydrogen-containing gas, for example, hydrogen (H) is supplied from the 2 nd gas supply pipe 232b into the processing chamber 201 through the MFC241b, the valve 243b, and the 2 nd nozzle 249b₂) A gas. That is, the 2 nd gas supply system is configured as a hydrogen-containing gas supply system that supplies a hydrogen-containing gas into the processing chamber 201. At the same time, the inert gas may be supplied from the 2 nd inert gas supply pipe 232g into the 2 nd gas supply pipe 232 b.

As the reducing gas, a hydrogen-containing gas, for example, H, is supplied from the 3 rd gas supply pipe 232c, the 4 th gas supply pipe 232d, and the 5 th gas supply pipe 232e into the processing chamber 201 through the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e, respectively₂A gas. That is, the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e supply H into the processing chamber 201₂A hydrogen gas nozzle of gas was used. The 1 st auxiliary gas supply system, the 2 nd auxiliary gas supply system, and the 3 rd auxiliary gas supply system each function as a hydrogen gas supply system.

Further, as the inert gas, for example, nitrogen (N) is supplied into the processing chamber 201 from the 3 rd inert gas supply pipe 232h, the 4 th inert gas supply pipe 232i, and the 5 th inert gas supply pipe 232j through the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e, respectively₂) A gas. That is, the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e are also used as inert gas nozzles for supplying an inert gas into the process chamber 201. The 1 st auxiliary gas supply system, the 2 nd auxiliary gas supply system, and the 3 rd auxiliary gas supply system also function as inactive gas supply systems, respectively. In the present embodiment, H supplied from the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e is supplied₂N in gas₂The flow rate of the gas is adjusted to function as an inert gas supply system.

An exhaust pipe 231 for exhausting the atmosphere in the processing chamber 201 is provided below the side wall of the reaction tube 203. A vacuum pump 246 as a vacuum exhaust device is connected to the exhaust pipe 231 via a Pressure sensor 245 as a Pressure detector (Pressure detecting unit) for detecting the Pressure in the processing chamber 201 and an APC (automatic Controller) valve 244 as a Pressure regulator (Pressure adjusting unit). The exhaust pipe 231, the APC valve 244, and the pressure sensor 245 mainly constitute an exhaust system. It is also conceivable to include the vacuum pump 246 in the exhaust system. The exhaust system is configured to be capable of performing vacuum exhaust so that the pressure in the processing chamber 201 reaches a predetermined pressure (vacuum degree) by adjusting the valve opening degree of the APC valve 244 based on the pressure information detected by the pressure sensor 245 while operating the vacuum pump 246.

A seal cap 219 serving as a furnace opening cover capable of hermetically sealing the lower end opening of the reaction tube 203 is provided below the reaction tube 203. An O-ring 220 as a sealing member is provided on the upper surface of the seal cap 219 to be in contact with the lower end of the reaction tube 203. A rotation mechanism 267 for rotating the wafer boat 217 as a substrate holder described later is provided on the side of the seal cap 219 opposite to the processing chamber 201. The rotary shaft 255 of the rotary mechanism 267 penetrates the seal cover 219 and is connected to the boat 217. The rotating mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The boat elevator 115 is configured to move the boat 217 into and out of the process chamber 201 by moving the seal cap 219 up and down.

The wafer boat 217 is made of a heat-resistant material such as quartz or silicon carbide, and is configured to support a plurality of wafers 200 in a horizontal posture in a plurality of stages while aligning the centers of the wafers with each other. A heat insulating member 218 made of a heat-resistant material such as quartz or silicon carbide is provided below the boat 217.

As shown in fig. 2, a temperature sensor 263 as a temperature detector is provided in the reaction tube 203. The temperature inside the processing chamber 201 is set to a desired temperature distribution by adjusting the current supply state to the heater 207 based on the temperature information detected by the temperature sensor 263.

As shown in fig. 3, the controller 121 serving as 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 121 d. The RAM121b, the storage device 121c, and the I/O port 121d are configured to be able to exchange data with the CPU121a via the internal bus 121 e. An input/output device 122 configured as a touch panel or the like, for example, is connected to the controller 121.

The storage device 121c is configured by, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 121c, a control program for controlling the operation of the substrate processing apparatus, and process steps, conditions, and the like of the film formation process described later are stored so as to be readable. The process steps are combined so that the controller 121 can perform each step in the substrate processing step described later to obtain a predetermined result, and function as a program. Hereinafter, the process, the control program, and the like are also referred to as simply "programs". In the present specification, the term "program" may be used to include only a process step, only a control step, or both. The RAM121b is configured as a memory area that temporarily holds programs, data, and the like read by the CPU121 a.

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

The CPU121a is configured to read and execute a control program from the storage device 121c, and read a process recipe from the storage device 121c in response to input of an operation command from the input/output device 122. The CPU121a is configured to control flow rate adjustment operations of the respective gases by the MFCs 241a to 241j, opening and closing operations of the valves 243a to 243j, opening and closing operations of the APC valve 244, pressure adjustment operations by the APC valve 244 of the pressure sensor 245, temperature adjustment operations of the heater 207 by the temperature sensor 263, start and stop of the vacuum pump 246, rotation and rotation speed adjustment operations of the boat 217 by the rotation mechanism 267, and lifting and lowering operations of the boat 217 by the boat lifter 115, in accordance with the read contents of the process recipe.

The controller 121 is not limited to a dedicated computer configuration, and may be a general-purpose computer configuration. For example, the controller 121 of the present embodiment can be configured by preparing an external storage device (for example, a magnetic disk such as a magnetic tape, a flexible disk, or a hard disk, an optical disk such as a CD or a DVD, an optical magnetic disk such as an MO, a USB memory, or a semiconductor memory such as a memory card) 123 storing the program, and installing the program in a general-purpose computer using the external storage device 123. The means for supplying the program to the computer is not limited to the case of supplying the program via the external storage device 123. For example, the program may be supplied using a communication means such as the internet or a dedicated line without passing through the external storage device 123. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, the above will be also simply referred to as "recording medium". Note that the term "recording medium" used in this specification may include only the storage device 121c alone, only the external storage device 123 alone, or both of them.

(2) Substrate processing procedure

Next, an example of a method of forming a silicon oxide film (SiO film) by oxidizing the surface of the wafer 200 on which a silicon (Si) film as a silicon-containing film is formed as one step of a manufacturing process of a semiconductor device (device) using the processing furnace of the substrate processing apparatus will be described. In the following description, the operations of the respective parts constituting the substrate processing apparatus are controlled by the controller 121. In the present specification, the term "surface of wafer" may be used to indicate a surface of a wafer itself or a surface of a predetermined layer or the like formed on a wafer. The term "substrate" used in this specification is the same as the term "wafer".

The film formation sequence of the present embodiment will be described specifically with reference to fig. 4. Fig. 4 is a diagram showing the gas supply timing in the film formation sequence according to the embodiment of the present invention.

Here, an example of performing the following steps as a film formation sequence of the SiO film will be described:

a step 1 of supplying O as an oxygen-containing gas to the heated wafer 200 in a processing chamber 201 as a processing container in an atmosphere of a 1 st pressure lower than atmospheric pressure₂Gas and H as hydrogen-containing gas₂A gas that oxidizes the surface of the wafer 200 on which the Si film, which is a silicon-containing film, is formed to form a silicon oxide layer (SiO layer 300b) as the 1 st oxide layer; and

a 2 nd step of supplying O as an oxygen-containing gas to the heated wafer 200 in a process container under an atmosphere of a 2 nd pressure which is different from the 1 st pressure and lower than the atmospheric pressure₂Gas and as a mixture ofH of Hydrogen gas₂The gas oxidizes the surface of the wafer 200 on which the SiO layer 300b is formed, thereby forming an SiO layer 300c as a 2 nd oxide layer.

In the present embodiment, the SiO layer 300c constitutes an SiO film formed in the present film formation sequence.

Further, an example will be described in which an initial step is performed before the 1 st step, in which O as an oxygen-containing gas is supplied into the processing container₂The gas oxidizes the surface of the wafer 200 on which the Si film is formed, and forms an SiO layer 300a as an initial oxide layer.

(wafer filling and boat loading)

When a plurality of wafers 200 are loaded on the boat 217 (wafer loading), the lower end opening of the reaction tube 203 is opened. As shown in fig. 1, the boat 217 supporting a plurality of wafers 200 is carried into the processing chamber 201 accommodating the wafers 200 by the boat elevator 115 (boat loading). In this state, the seal cap 219 seals the lower end of the reaction tube 203.

(pressure control and temperature control)

The inside of the processing chamber 201 is vacuum-exhausted by a vacuum pump 246. At this time, the pressure in the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure information so that the pressure in the processing chamber 201 reaches a desired pressure (pressure regulation). The vacuum pump 246 is maintained in operation at least until the process for the wafer 200 is completed. In addition, heating is performed by the heater 207 to reach a desired temperature in the processing chamber 201. At this time, the energization state 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 becomes a desired temperature distribution (temperature adjustment). Thereby, the wafer 200 housed in the processing chamber 201 is heated to a desired temperature. It should be noted that the heating in the processing chamber 201 by the heater 207 is continued at least until the processing for the wafer 200 is completed. Next, the rotation of the boat 217 and the wafers 200 by the rotation mechanism 267 is started. The rotation of the boat 217 and the wafers 200 by the rotation mechanism 267 is continued at least until the process for the wafers 200 is completed.

(initial step (initial oxide layer formation step))

First, as a pretreatment, an SiO layer as an initial oxide layer is formed on the surface of the wafer 200.

The valve 243a of the 1 st gas supply pipe 232a is opened to make O as oxygen-containing gas₂The gas flows into the 1 st gas supply pipe 232 a. O is₂The gas flows from the 1 st gas supply pipe 232a, and the flow rate of the gas is adjusted by the MFC241 a. Flow regulated O₂The gas is supplied into the processing chamber 201 from the gas supply hole 250a of the 1 st nozzle 249a and is exhausted from the exhaust pipe 231. At this time, O is supplied to the heated wafer 200₂A gas. In the present embodiment, a gas substantially not containing hydrogen is used as the oxygen-containing gas, and O is particularly preferable as an example₂The gas is supplied as an oxygen-containing gas alone into the processing chamber 201. That is, the oxygen-containing gas in this step is O₂Gas, free of hydrogen.

At this time, the valve 243f of the 1 st inert gas supply pipe 232f may be opened, and an inert gas, for example, N, which is a carrier gas of the oxygen-containing gas may be supplied from the 1 st inert gas supply pipe 232f₂A gas. N is a radical of₂The gas is flow-regulated by the MFC241f and supplied into the 1 st gas supply pipe 232 a. Flow regulated N₂Gas is mixed with O in the 1 st gas supply pipe 232a₂The gases are mixed and supplied from the 1 st nozzle 249a into the heated processing chamber 201 in a reduced pressure state, and are exhausted from the exhaust pipe 231. In this case, O is prevented₂The gas enters the 2 nd to 5 th gas supply pipes 232b to 232e, the valves 243g to 243j are opened, and N is set₂The gas flows into the 2 nd, 3 rd, 4 th, and 5 th inactive gas supply pipes 232g, 232h, 232i, and 232 j.

At this time, the opening degree of the APC valve 244 is controlled so that the pressure in the processing chamber 201 is, for example, in the range of 1 to 1330Pa, preferably 20 to 133Pa (for example, 73 Pa). O controlled by MFC241a₂The supply flow rate of the gas is, for example, in the range of 0.01 to 20.0slmFlow (e.g., 8.7 slm). N controlled by MFC241f₂The supply flow rate of the gas is, for example, in the range of 0 to 40.0slm (e.g., 1 slm). Supplying O to the wafer 200₂The gas supply time, which is the time of the gas, is, for example, 10 to 600 seconds (e.g., 180 seconds). At this time, the temperature of the heater 207 is set so that the temperature of the wafer 200 becomes, for example, a temperature within a range of 400 to 1000 ℃ (for example, a temperature of 630 ℃).

The Si film on the wafer 200 is oxidized from the surface by this step, and as shown in fig. 5 (a), an SiO layer 300a as an initial oxide layer (base oxide layer) is formed on the surface of the wafer 200 to have a thickness (e.g., 1nm) in the range of, for example, 0.1 to 2 nm. The film formation rate (oxidation rate) for forming the initial oxide layer in this step is preferably lower than the film formation rate for forming the SiO layer in the later-described 1 st and 2 nd stepsLess than one minute. In this manner, by forming the oxide layer at a sufficiently low oxidation rate in the initial step, the film thickness distribution (in particular, in-plane uniformity, which is film thickness uniformity in the same substrate plane) can be easily controlled in the subsequent 1 st step and 2 nd step.

(step 1 of Forming oxide layer)

Next, an SiO layer 300b as a 1 st oxide layer is formed on the surface of the wafer 200 on which the preliminary oxide layer is formed through the preliminary process.

[ Low pressure Oxidation treatment ]

While continuing to perform O from the 1 st nozzle 249a₂Supply of gas and N₂In the state where the gas is supplied, the controller 121 controls the APC valve 244 so that the pressure in the processing chamber 201 becomes a predetermined pressure lower than the atmospheric pressure (101.3 kPa). At this time, the valve 243b of the 2 nd gas supply pipe 232b is opened to make H as the hydrogen-containing gas₂The gas flows into the 2 nd gas supply pipe 232 b. H₂The gas flows from the 2 nd gas supply pipe 232b, and is flow-regulated by the MFC241 b. Flow regulated H₂Gas is supplied into the processing chamber 201 from the gas supply hole 250b of the 2 nd nozzle 249b and exhausted from the exhaust gasThe pipe 231 is vented. At this time, O as an oxygen-containing gas₂Gas, H₂Gas, N as carrier gas₂The gas is supplied from the outer periphery side of the heated wafer 200 toward the center thereof. In addition, at this time, O in the processing chamber 201₂Gas and H₂Concentration ratio of gas (i.e., O supplied into the processing chamber 201)₂Gas and H₂Flow rate ratio of gas) is set to a predetermined concentration ratio region (for example, 80: 20-35: 65 range).

In this case, in the present embodiment, the valve 243g of the 2 nd inert gas supply pipe 232g is opened, and the gas is supplied from the 2 nd inert gas supply pipe 232g as H₂Inert gas (e.g. N) as carrier gas for the gas₂Gas). N is a radical of₂The gas is flow-regulated by the MFC241g and supplied into the 2 nd gas supply pipe 232 b. Flow regulated N₂Gas is supplied to the 2 nd gas supply pipe 232b together with H₂The gas is mixed and supplied from the 2 nd nozzle 249b toward the wafer 200 from the outer peripheral side toward the center thereof.

(auxiliary H)₂Gas supply)

In this case, in the present embodiment, H is set to₂The gas flows into the 3 rd gas supply pipe 232c, the 4 th gas supply pipe 232d and the 5 th gas supply pipe 232e (H to be supplied from these gas supply pipes)₂Gas referred to as auxiliary H₂Gas). Auxiliary H₂The gas is supplied from the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e toward the wafer 200 from the outer peripheral side thereof toward the center.

Here, in this step and the later-described 2 nd step, in order to adjust the film formation distribution of the SiO layer formed on the surface of the wafer 200, auxiliary H is used as needed₂Gas and flow regulation is performed. Specifically, the assist H is supplied from each nozzle₂The flow rate of the gas is adjusted so that H in the in-plane direction (i.e., horizontal direction) of the wafer 200 can be finely adjusted₂Gas concentration, in particular with O₂Distribution of concentration ratio of gas. In addition, since the nozzles are different in position in the height direction from each other, the nozzles can be arranged in pairsAuxiliary of nozzle supply H₂The flow rate of the gas is adjusted so as to finely adjust H in the inter-plane direction (i.e., vertical direction) of the wafer 200₂Gas concentration, in particular with O₂The distribution of the concentration ratio of the gas is adjusted.

By finely aligning H in this manner₂Gas concentration, in particular with O₂By adjusting the distribution of the concentration ratio of the gas, the distribution of the oxidation rate (film formation distribution of the SiO layer) in the surface of the wafer 200 and between the wafers can be adjusted to be closer to a desired distribution.

(subsidiary N)₂Gas supply)

In this case, N may be supplied as the inert gas from the 3 rd gas supply pipe 232c, the 4 th gas supply pipe 232d, and the 5 th gas supply pipe 232e by opening the valves 243h, 243i, and 243j₂Gas (N to be supplied from these gas supply pipes₂Gas known as auxiliary N₂Gas). Auxiliary N₂The gas is supplied to the gas supply pipes H and H in the 3 rd, 4 th and 5 th gas supply pipes 232c, 232d and 232e₂The gases are mixed and supplied from the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d, and the 3 rd auxiliary nozzle 249e toward the wafer 200 accommodated in the processing chamber 201 from the outer peripheral side toward the center thereof.

At this time, the opening degree of the APC valve 244 is adjusted to set the pressure in the processing chamber 201 to the 1 st pressure lower than the atmospheric pressure, for example, a pressure within a range of 1 to 665Pa (for example, 532 Pa). O controlled by MFC241a₂The supply flow rate of the gas is, for example, in the range of 0.1 to 20.0slm (e.g., 10.0 slm). N controlled by MFC241f₂The supply flow rates of the gases are, for example, in the range of 0 to 40.0slm (e.g., 19.0 slm). H controlled by MFC241b₂The supply flow rate of the gas is, for example, in the range of 0.1 to 10.0slm (e.g., 3.0 slm). N controlled by MFC241g₂The supply flow rate of the gas is, for example, in the range of 0 to 40.0slm (e.g., 1.5 slm). H is to be₂Gas and O₂The gas is supplied to the wafer 200 for a time period within a range of, for example, 0.1 to 300 minutes (for example, 28.25 minutes). At this time, the temperature of the heater 207 is set so that of the wafer 200The temperature is, for example, in the range of 400 to 1000 ℃ (for example, 630 ℃). Each H controlled by MFC241 c-241 e₂The supply flow rates of the gases are set to, for example, 0 to

A flow rate in the range of 10.0slm (e.g., 0.3 slm). N controlled by MFCs 241 h-241 j₂The supply flow rates of the gases are, for example, in the range of 0 to 40.0slm (e.g., 3.0 slm).

In this step, O is supplied into the processing chamber 201 under the above-described conditions₂Gas and H₂Gas, thereby O₂Gas and H₂The gas is thermally activated by a non-plasma to react with the gas, thereby generating atomic oxygen (O) or the like containing oxygen but not moisture (H)₂O) is oxidized. Then, the surface of the wafer 200 on which the initial oxide layer (SiO layer 300a) is formed is oxidized mainly by the oxidation species, and an SiO layer 300b as a 1 st oxide layer is formed. Here, the SiO layer 300b as the 1 st oxide layer represents an SiO layer formed on the surface of the wafer 200 after this step. Therefore, in the case of the present embodiment, the SiO layer 300b includes an oxide layer formed by the initial oxidation process. In the case where only the present step is performed without the initial oxidation step, the oxide layer formed only in the present step may be referred to as a 1 st oxide layer.

Here, in this step, the pressure (1 st pressure) in the processing chamber 201 is adjusted to a pressure different from the pressure (2 nd pressure) in the next 2 nd step. By setting the processing pressure in this manner, the variation in the distribution of the oxidation rate in the radial direction from the outer peripheral portion (the vicinity of the outer periphery) to the central portion of the wafer 200 can be made different from that in the 2 nd step.

In the present embodiment, in the present step, the adjustment is performed so that the 1 st pressure is lower than the 2 nd pressure. By setting the processing pressure in this manner, the gas easily reaches the center of the wafer 200 and the oxidation reaction easily occurs at the center of the wafer 200, as compared with the 2 nd step. Therefore, the oxidation rate of the central portion in the surface of the wafer 200 in the 1 st step is higher than that in the 2 nd step, and the oxidation rate of the outer peripheral portion in the surface of the wafer 200 in the 1 st step is lower than that in the 2 nd step.

In the present embodiment, the 1 st pressure is adjusted (set) in the present step so that the oxidation rate increases from the outer peripheral portion toward the center portion in the radial direction of the wafer 200 (that is, the distribution of the oxidation rate varies in a convex shape in the radial direction). As a result, as shown in fig. 5 (B), the SiO layer 300B is formed so that the thickness distribution of the SiO layer 300B in the center portion of the wafer 200 is larger than the thickness distribution of the outer peripheral portion of the wafer 200 and the SiO layer 300B is convex in the surface of the wafer 200.

(step 2 of Forming oxide layer)

Next, an SiO layer 300c as a 2 nd oxide layer is formed on the surface of the wafer 200 on which the 1 st oxide layer is formed through the 1 st step.

[ high pressure Oxidation treatment ]

While continuing to perform O from the 1 st nozzle 249a₂Gas and N₂Gas supply and H from the 2 nd nozzle 249b₂Gas and N₂Gas supply, H from the 1 st auxiliary nozzle 249c, the 2 nd auxiliary nozzle 249d and the 3 rd auxiliary nozzle 249e₂Gas and N₂In the state where the gas is supplied, the controller 121 controls the APC valve 244 so that the pressure in the processing chamber 201 becomes a predetermined pressure higher than the 1 st pressure and lower than the atmospheric pressure. At this time, similarly to the step 1, O is supplied from the outer peripheral side of the wafer 200 toward the center₂Gas, H₂Gas, and N₂A gas. In addition, at this time, O₂Gas and H₂The concentration ratio of the gas is set to a predetermined value in a predetermined concentration ratio region (for example, in the range of 80: 20 to 35: 65). Here, as in the above-described step 1, in order to adjust the film formation distribution of the SiO layer formed on the surface of the wafer 200, auxiliary H is used as needed₂Gas and auxiliary N₂A gas.

At this time, the opening degree of the APC valve 244 is adjusted so that the pressure in the processing chamber 201 is set to the 2 nd pressure which is different from the 1 st pressure and lower than the atmospheric pressure, that is, a pressure (e.g., 665Pa) within a range of, for example, 399 to 13300 Pa. O controlled by MFC241a₂The supply flow rate of the gas is, for example, in the range of 0.1 to 20.0slm (e.g., 10.0 slm). N controlled by MFC241f₂The supply flow rate of the gas is, for example, in the range of 0 to 40.0slm (for example3.0 slm). That is, let N be controlled by MFC241f₂The supply flow rate of the gas is controlled to N controlled by MFC241f in step 1₂The supply flow rate of the gas is changed. Specifically, let N be controlled by MFC241f₂The supply flow rate of the gas is smaller than N controlled by MFC241f in step 1₂The supply flow rate of the gas. H controlled by MFC241b₂The supply flow rate of the gas is, for example, in the range of 0.1 to 10.0slm (e.g., 3.0 slm). N controlled by MFC241g₂The supply flow rate of the gas is, for example, in the range of 0.1 to 40.0slm (e.g., 1.5 slm). Supply H to the wafer 200₂Gas and O₂The gas time is, for example, a time within a range of 0.1 to 300 minutes (for example, 11.75 minutes). At this time, the temperature of the heater 207 is set so that the temperature of the wafer 200 becomes, for example, a temperature within a range of 400 to 1000 ℃ (for example, a temperature of 630 ℃). H controlled by MFCs 241 c-241 e₂The supply flow rates of the gases are, for example, in the range of 0.1 to 10.0slm (e.g., 0.3 slm). N controlled by MFCs 241 h-241 j₂The supply flow rates of the gases are, for example, in the range of 0.1 to 40.0slm (e.g., 3.0 slm).

In this step, O is supplied into the processing chamber 201 under the above-described conditions₂Gas and H₂Gas thereby to make O₂Gas and H₂The gas is thermally activated with a non-plasma to produce oxidizing species. The surface of the wafer 200 on which the SiO layer 300b is formed is oxidized mainly using the oxidation species so that the film thickness of the SiO layer 300b is increased, thereby forming the SiO layer 300c as the 2 nd oxide layer.

Here, in this step, as described above, the 2 nd pressure is adjusted so as to be a pressure different from the 1 st pressure. By varying the process pressure for each step in this manner, O can be adjusted for each step₂The probability (ease or difficulty of reaching) that an oxidizing gas such as a gas reaches the center portion from the outer periphery of the wafer 200. That is, by making the process pressure different for each process, the distribution of the oxidation rate in the radial direction of the wafer 200 can be made different between the outer peripheral portion and the central portion of the wafer 200.

For example, in the present embodiment, as described above, the adjustment is made so that the 2 nd pressure is higher than the 1 st pressure. By setting the processing pressure in this manner, the gas is less likely to reach the center of the wafer 200 than in the step 1, and an oxidation reaction is more likely to occur in the outer peripheral portion of the wafer 200 on the upstream side of the gas flow. Therefore, the oxidation rate of the central portion of the wafer 200 in the 2 nd step can be made smaller than that in the 1 st step, and the oxidation rate of the outer peripheral portion of the wafer 200 in the 2 nd step can be made larger than that in the 1 st step.

By performing the 1 st step and the 2 nd step, which have different oxidation rate distributions in the radial direction of the wafer 200, in combination with the pressure conditions, the film thickness distribution of the SiO layer 300c in the radial direction of the wafer 200 can be made close to a desired distribution. That is, controllability of the film thickness distribution in the wafer 200 plane can be improved.

In the present embodiment, in the present step, the 2 nd pressure is adjusted (set) so that the oxidation rate decreases from the outer peripheral portion toward the center portion in the radial direction of the wafer 200 (that is, the distribution of the oxidation rate varies in a concave shape in the radial direction). Here, assuming that the 1 st step is not performed and the 2 nd step is performed, the thickness of the SiO layer formed in the 2 nd step is larger at the outer peripheral portion of the wafer 200 than at the center of the wafer 200, and the SiO layer is formed so as to have a concave shape in the surface of the wafer 200.

In the present embodiment, since the SiO layer 300b is formed in the 1 st step so that the thickness distribution becomes convex on the surface of the wafer 200, the in-plane thickness distribution of the SiO layer 300C formed after the present step can be brought into a nearly uniform state as shown in fig. 5 (C) by performing the present step. That is, by performing the 1 st step in which the oxidation rate of the central portion of the wafer 200 is higher than that of the outer peripheral portion in combination with the 2 nd step in which the oxidation rate of the outer peripheral portion of the wafer 200 is higher than that of the central portion, the uneven distribution of the oxidation rate in the 1 st step can be compensated for by the uneven distribution in the 2 nd step, and the SiO layer 300c having excellent in-plane uniformity of film thickness can be formed.

N supplied from the 1 st nozzle 249a and the 2 nd nozzle 249b is used₂The supply flow rate of the gas is smaller than that in the 1 st step, so that the oxidation rate of the SiO layer 300c formed at the center of the wafer can be increasedThe rate is slower than the outer periphery of the wafer 200. That is, it is also possible to reduce N as a carrier gas in the 2 nd step₂The supply flow rate of the gas, thereby further strengthening the distribution of the oxidation rate of the concave shape in the radial direction of the wafer 200.

In the 1 st step, N supplied from the 1 st nozzle 249a and the 2 nd nozzle 249b is increased₂The supply flow rate of the gas is such that the oxidation rate of the SiO layer 300b formed at the center of the wafer can be made faster than the outer peripheral portion of the wafer 200. That is, it is also possible to increase N as the carrier gas in the 1 st step₂The supply flow rate of the gas, thereby further enhancing the distribution of the oxidation rate in a convex shape in the radial direction of the wafer 200.

Then, the valves 243a, 243b, 3 rd, 4 th, and 5 th gas supply pipes 232a, 232d, 232e of the 1 st, 2 nd, 3 rd, 4 th, and 5 th gas supply pipes 232a, 232b, 232e are closed, respectively, to thereby close the O-ring₂Gas, H₂The supply of gas is stopped. At this time, the inside of the processing chamber 201 is evacuated by the vacuum pump 246 while keeping the APC valve 244 open, and O remaining in the processing chamber 201 and remaining unreacted or participating in SiO layer formation is removed₂Gas, H₂Gas is exhausted from the process chamber 201 (residual gas removal).

(purge and atmospheric pressure recovery)

N as an inert gas is supplied into the processing chamber 201 from the 1 st inert gas supply pipe 232f, the 2 nd inert gas supply pipe 232g, the 3 rd inert gas supply pipe 232h, the 4 th inert gas supply pipe 232i and the 5 th inert gas supply pipe 232j while the valves 243f to 243j are kept open₂And the gas is discharged from the gas discharge pipe 231. N is a radical of₂The gas functions as a purge gas, and the gas remaining in the processing chamber 201 is removed (purged) from the processing chamber 201. Thereafter, the atmosphere in the processing chamber 201 is replaced with an inert gas, and the pressure in the processing chamber 201 is returned to the normal pressure (atmospheric pressure recovery).

(boat unloading and wafer taking out)

Thereafter, the processed wafers 200 are carried out from the lower end of the reaction tube 203 to the outside of the reaction tube 203 by the boat elevator 115 while being held on the boat 217 (boat unloading). Thereafter, the processed wafers 200 are taken out from the boat 217 (wafer take-out).

(3) Relationship between treatment time and Oxidation Rate

Next, the use of H in the same manner as in the 1 st step and the 2 nd step will be described₂Gas and O₂Oxidation rate of gas in the case of forming a SiO film on the wafer surface. FIG. 6 illustrates the use of H at a wafer temperature of 600 deg.C₂Gas and O₂H-based in the case of gas-forming SiO films₂Gas and O₂Graph of the relationship between the time of oxidation treatment for gas supply and the film thickness of the formed SiO film.

As can be seen from FIG. 6, in the case of use H₂Gas and O₂In the case where a gas forms an SiO film on the wafer surface, the oxidation rate is particularly high immediately after the gas is supplied. That is, in the initial stage immediately after the gas supply, since the SiO film is rapidly formed in a short time with a high oxidation rate, it is difficult to control the film formation distribution in the wafer surface and between wafers. Thus, in the initial step of the present embodiment, the use of O having a low oxidation rate is performed in the initial stage of the film formation₂By forming an initial oxide layer having high in-plane uniformity by oxidizing the gas, it is possible to avoid extreme variation in the oxidation rate distribution that is conspicuously observed in the initial stage in the first and second steps to be performed later, and to improve the controllability of the film thickness distribution of the SiO layer (particularly, in-plane film thickness uniformity).

(4)H₂Concentration ratio dependence of Oxidation Rate

Next, H is explained₂Gas and O₂H in gas₂The ratio of (c) to (d) is related to the film formation rate (oxidation rate). FIG. 7 shows the supply of disilicon hexachloride (Si) as Si source gas to the wafer surface alternately and repeatedly₂Cl₆) Process for producing gas and process for using gas H₂Gas and O₂A step of gas oxidation treatment to form an SiO film in H₂Gas and O₂H in gas₂The ratio of (A) to (B) is different from the ratio of (B) to (C)And (5) fruit. That is, the graph shows a case where the condition that the film formation rate is higher is the condition that the oxidation rate is higher.

H of each plot in FIG. 7₂The concentrations indicated 2%, 18.4%, 80%, 97.4%, respectively.

As shown in FIG. 7, by making H₂Flow rate of gas relative to H₂Gas and O₂The ratio of the total flow rate of the gases (concentration ratio) is changed, whereby the film formation rate of the SiO film formed on the wafer surface can be controlled. Specifically, by mixing O₂Gas and H₂The concentration ratio of the gas was set to 80: 20-35: 65, so that the oxidation rate can be increased. In addition, by adding O₂Gas and H₂The concentration ratio of the gas was set to 80: 20-35: a specified value outside the range of 65, so that the oxidation rate can be reduced.

(5) Pressure dependence of film thickness distribution

Next, the pressure dependence of the film thickness distribution of the SiO film will be described. FIG. 8 shows O₂Gas and H₂A graph showing the relationship between the pressure in the processing chamber 201 and the in-plane uniformity when the concentration ratio of the gas is 33%. In fig. 8, 0 of the vertical axis indicates a case where a film is formed in a flat shape on the wafer surface, a (positive) value of the vertical axis greater than 0 indicates a case where a film is formed in a convex shape on the wafer surface, and a (negative) value of the vertical axis less than 0 indicates a case where a film is formed in a concave shape on the wafer surface. As the wafer, a bare wafer having no pattern formed on the surface thereof was used.

As can be seen from fig. 8, when the processing conditions other than the pressure are the same, the higher the pressure in the processing chamber 201 is, the stronger the tendency that the film is formed on the wafer surface in a concave shape is. This is presumably because the number of molecules in the processing chamber 201 is reduced by setting the low pressure condition, the mean free path becomes longer, and the probability of the gas reaching the wafer center increases, whereas the high pressure condition increases the number of molecules in the processing chamber 201, the mean free path becomes shorter, and the probability of the gas reaching the wafer center decreases.

(6) Other embodiments

In the above embodiment, the case where the 1 st step and the 2 nd step are performed in the above order has been described, but the present invention is not limited to this case. For example, the second step 2 may be performed first, and the first step 1 may be performed after the SiO layer having a concave shape is formed in the wafer 200 surface, and the film thickness distribution in the wafer 200 surface may be adjusted so as to compensate the film thickness distribution having a concave shape.

In the above embodiment, O is used for the initial step₂The case of gas has been described, but the present invention is not limited to this case. For example, O may be used also in the initial step₂Gas and H₂The gas forms an initial oxide layer. In this case, O in the processing chamber 201₂Gas and H₂The concentration ratio of the gas used was 80: 20-35: a specified value outside the range of 65. That is, a concentration ratio region where the oxidation rate is low is used, preferably the oxidation rate isConcentration ratio in the region below/min.

In the above embodiment, the case where O is used in the initial step is explained₂Gas, but the present invention is not limited to this case. Preference is given to using a catalyst having an oxidation rate ofFilm forming gas in a region of less than/minute. For example, in the use of ozone (O)₃) The oxidation rate can be reduced even in the case of the like, and the above-described effects can be obtained similarly.

In the above-described embodiments, the case where the SiO layer is formed on the wafer surface on which the Si-containing film is formed has been described, but the present invention is not limited to this case, and the present invention can be similarly applied to the case where the oxide layer is formed on the wafer surface on which another metal-containing film is formed.

In the above embodiment, it has been described that O is supplied from the 1 st nozzle 249a and the 2 nd nozzle 249b independently₂Gas and H₂Gas, but the present invention is not limited to this case. For example, the O may be supplied from one nozzle₂Gas and H₂A mixture of gases.

In the above embodiment, it has been described that O is used as the oxygen-containing gas in any of the initial step, the 1 st step and the 2 nd step₂Gas, but the present invention is not limited to this case. As the oxygen-containing gas, O may be used₃Other gases such as gas and NO gas, and different oxygen-containing gases may be used in the respective steps.

While various exemplary embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and may be appropriately combined and used.

(7) Examples of the embodiments

As an example, a SiO film was formed on the wafer surface by the substrate processing step shown in fig. 4 using the substrate processing apparatus shown in fig. 1. As the wafer, a bare wafer having no pattern formed on the surface thereof was used. O in the initial step of the substrate treatment step₂Gas supply time was set to 3 minutes, and H in step 1₂Gas and O₂Gas supply time was 27 minutes, and H in step 2₂Gas and O₂The gas supply time was set to 13 minutes. The processing conditions in the other steps are predetermined conditions within the processing condition range in the above embodiment.

As a comparative example, only the 1 st step of the substrate processing steps shown in fig. 4 was performed using the substrate processing apparatus shown in fig. 1, and an SiO film was formed on the wafer surface. As the wafer, a bare wafer was used as in the example. Step 1H₂Gas and O₂The gas supply time was set to 40 minutes. The other processing conditions were the predetermined conditions in the above-described examples.

As shown in fig. 9 (D), the SiO film formed on the surface of the wafer placed on the upper portion of the boat in the comparative example had an in-plane uniformity of + 4.62%, as shown in fig. 9 (E), the SiO film formed on the surface of the wafer placed on the central portion of the boat in the comparative example had an in-plane uniformity of + 3.64%, as shown in fig. 9 (F), the SiO film formed on the surface of the wafer placed on the lower portion of the boat in the comparative example had an in-plane uniformity of + 6%, and the SiO film was formed in a convex shape on the surface of the wafer placed on the boat in the range from the lower region to the upper region.

On the other hand, as shown in fig. 9 (a), the SiO film formed on the surface of the wafer placed on the upper portion of the boat had an in-plane uniformity of + 1.02%, as shown in fig. 9 (B), the SiO film formed on the surface of the wafer placed on the central portion of the boat had an in-plane uniformity of-0.98%, as shown in fig. 9 (C), the SiO film formed on the surface of the wafer placed on the lower portion of the boat had an in-plane uniformity of-1.70%, and the SiO film formed on the surface of the wafer placed on the lower portion of the boat had an in-plane uniformity that was improved over the comparative example over the range from the lower region to the upper region of the boat.

From the above results, it was confirmed that the in-plane uniformity of the oxide film formed on the wafer surface was improved by performing the substrate treatment process of the present embodiment.

Description of the reference numerals

10 substrate processing apparatus

121 controller

200 wafer (substrate)

201 processing chamber