US-12623258-B2 - Gas cleaning method, method of processing substrate, method of manufacturing semiconductor device, recording medium, and substrate processing apparatus

Abstract

A gas cleaning method includes: (a) removing a first metal element as one of contaminants from a process chamber by supplying a chlorine-containing gas into the process chamber without supplying an oxygen-containing gas; and (b) removing a second metal element as another one of the contaminants from the process chamber by supplying the oxygen-containing gas into the process chamber, wherein (b) is performed after (a).

Inventors

• Takahiro Kobayashi
• Iwao Nakamura
• Toru Harada
• Hisashi Nomura
• Sadayoshi Horii

Assignees

• Kokusai Electric Corporation

Dates

Publication Date

20260512

Application Date

20230201

Priority Date

20220318

Claims (17)

1. 1 . A gas cleaning method comprising: (a) removing a first metal element as one of contaminants from a process chamber by supplying a chlorine-containing gas into the process chamber without supplying an oxygen-containing gas; and (b) removing a second metal element as another one of the contaminants from the process chamber by supplying the oxygen-containing gas into the process chamber, wherein (b) is performed after (a), and wherein (a) and (b) are performed before performing a process of oxidizing, diffusing, and annealing a substrate in the process chamber.
2. 2 . The gas cleaning method of claim 1 , further comprising: (c) forming a protective oxide film on at least one selected from the group of an inner surface of the process chamber, a component disposed in the process chamber, and a dummy substrate for adhesion of the contaminants which is disposed in the process chamber, wherein (c) is performed before (a).
3. 3 . The gas cleaning method of claim 1 , wherein, in (a), the first metal element is removed by being chlorinated and vaporized, and wherein, in (b), the second metal element is removed by being oxidized and vaporized.
4. 4 . The gas cleaning method of claim 1 , wherein the chlorine-containing gas is a mixed gas containing HCl gas and an inert gas, and wherein the first metal element includes at least one selected from the group of Fe, Al, Cr, Ni, and Ti.
5. 5 . The gas cleaning method of claim 1 , wherein the second metal element includes at least one selected from the group of Mg, Ca, and Na.
6. 6 . The gas cleaning method of claim 1 , wherein the oxygen-containing gas includes O 2 gas.
7. 7 . The gas cleaning method of claim 1 , wherein (b) is continuously performed after (a).
8. 8 . The gas cleaning method of claim 1 , wherein the process chamber is made of quartz, and wherein a component for supporting the substrate, which is disposed in the process chamber, is made of silicon, quartz, or SiC.
9. 9 . The gas cleaning method of claim 4 , wherein the inert gas includes at least one selected from the group of N 2 and Ar.
10. 10 . The gas cleaning method of claim 1 , wherein (a) and (b) are performed in a state in which a dummy substrate for adhesion of the contaminants is disposed in the process chamber.
11. 11 . The gas cleaning method of claim 1 , wherein, in (b), the oxygen-containing gas is supplied to have an oxygen partial pressure for passively oxidizing a component disposed in the process chamber.
12. 12 . The gas cleaning method of claim 1 , wherein (a) and (b) are performed continuously at an equal processing temperature between 800 degrees C. and 1,300 degrees C.
13. 13 . The gas cleaning method of claim 1 , wherein (a) and (b) are repeatedly performed multiple times.
14. 14 . A non-transitory computer-readable recording medium storing a program that causes, by a computer, a substrate processing apparatus to perform a process comprising the gas cleaning method of claim 1 .
15. 15 . A method of processing a substrate, comprising: gas cleaning of removing contaminants containing a first metal element and a second metal element from a process chamber; and processing the substrate by supplying a processing gas to the substrate in the process chamber, wherein the gas cleaning comprises: (a) removing the first metal element by supplying a chlorine-containing gas into the process chamber without supplying an oxygen-containing gas; and (b) removing the second metal element by supplying the oxygen-containing gas into the process chamber, wherein (b) is performed after (a), and wherein (a) and (b) are performed before performing a process of oxidizing, diffusing, and annealing the substrate in the process chamber.
16. 16 . A method of manufacturing a semiconductor device, comprising the method of claim 15 .
17. 17 . A substrate processing apparatus comprising: a process chamber in which a substrate is accommodated; a gas supplier connected to the process chamber and configured to supply a processing gas, a chlorine-containing gas, and an oxygen-containing gas into the process chamber; and a controller configured to be capable of controlling the gas supplier so as to perform a process including: (a) removing a first metal element as one of contaminants from the process chamber by supplying the chlorine-containing gas into the process chamber without supplying the oxygen-containing gas; and (b) removing a second metal element as another one of the contaminants from the process chamber by supplying the oxygen-containing gas into the process chamber after (a), and wherein (a) and (b) are performed before performing a process of oxidizing, diffusing, and annealing the substrate in the process chamber.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-044570, filed on Mar. 18, 2022, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a gas cleaning method, a method of processing a substrate, a method of manufacturing a semiconductor device, a recording medium, and a substrate processing apparatus. BACKGROUND As a process of manufacturing a semiconductor device, a process of cleaning contaminants in a process chamber may be performed before processing a substrate. The related art discloses a cleaning method of removing a SiC film formed on a member in a process chamber by gas cleaning while preventing an inner wall of a graphite nozzle from being excessively etched. SUMMARY In a cleaning method performed in the state in which an oxygen-containing gas is present in the process chamber, metal impurities in the process chamber may be oxidized, which may make it difficult to etch the metal impurities and remove the metal impurities from the process chamber. As a result, the surface of a substrate may be contaminated with metal impurities and the thickness of an oxide film formed on the surface of the substrate may be uneven. The present disclosure provides a technique capable of forming a film having a more uniform thickness on the surface of a substrate. According to one embodiment of the present disclosure, there is provided a gas cleaning method including: (a) removing a first metal element as one of contaminants from a process chamber by supplying a chlorine-containing gas into the process chamber without supplying an oxygen-containing gas; and (b) removing a second metal element as another one of the contaminants from the process chamber by supplying the oxygen-containing gas into the process chamber, wherein (b) is performed after (a). The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure. FIG. 1 is a schematic configuration of a vertical process furnace of a substrate processing apparatus suitably used in embodiments of the present disclosure, in which a portion of a process furnace 202 is shown in a vertical cross section. FIG. 2 is a schematic configuration of a controller 121 of the substrate processing apparatus suitably used in embodiments of the present disclosure, in which a control system of the controller 121 is shown in a block diagram. FIG. 3 is a flowchart of a gas cleaning process according to embodiments of the present disclosure. FIG. 4 is a flowchart of a process performed by a substrate processing apparatus according to embodiments of the present disclosure. FIG. 5 is a view showing relationships between elements and standard electrode potentials, standard production enthalpies of chlorides, and standard production enthalpies of oxides. FIG. 6 is a graph showing an aluminum contamination density (number of atoms per unit area) in a process chamber with respect to an integrated flow time (hours) of a mixed gas of HCl and N2. FIG. 7 is a graph showing a film thickness range versus the integrated flow time (hours) of a mixed gas of HCl and N2. DETAILED DESCRIPTION Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments. Embodiments of the Present Disclosure Embodiments of the present disclosure will be described below mainly with reference to FIGS. 1 to 4. The drawings used in the following description are all schematic, and the dimensional relationship of respective elements, the ratios of respective elements, and the like shown in the drawings do not necessarily match the actual ones. In addition, the dimensional relationships of respective elements, the ratio of respective elements, and the like do not necessarily match among a plurality of drawings. (1) Configuration of Substrate Processing Apparatus As illustrated in FIG. 1, a process furnace 202 includes a heater 207 as a temperature regulator (heating part). The heater 207 has a cylindrical shape and is installed vertically by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation part) that thermally activates (excites) gas. Inside the heater 207, a reaction tube 203 and a soaking tube 209 are arranged concentrically with the heater 207. The reaction tube 203 is made of a heat-resistant material such a