US-12624444-B2 - Film forming method and film forming apparatus

US12624444B2US 12624444 B2US12624444 B2US 12624444B2US-12624444-B2

Abstract

A film forming method forms a film on a substrate by plasma in a processing container including a stage configured to hold the substrate thereon, wherein the film forming method includes: (a) a step of supplying a raw material gas and a reaction gas as a processing gas to the processing container; and (b) a step of generating plasma of the processing gas using a radio-frequency power of 100 MHz or higher.

Inventors

Nobuo Matsuki
Yoshinori Morisada
Takayuki Komiya
Satoru Kawakami
Taro Ikeda
Toshihiko Iwao

Assignees

TOKYO ELECTRON LIMITED

Dates

Publication Date: 20260512
Application Date: 20210812
Priority Date: 20200826

Claims (13)

1 . A film forming method that forms a film on a substrate by plasma in a processing container including a stage configured to hold the substrate thereon, the film forming method comprising: (a) supplying a raw material gas to the processing container; (b) purging the processing container with a nitrogen gas (N 2 gas) and an inert gas; and (c) generating plasma of the nitrogen gas by supplying a radio-frequency power of 180 MHz or higher and equal to or lower than 220 MHz to the processing container in which the nitrogen gas and the inert gas are supplied.
2 . The film forming method of claim 1 , wherein the substrate includes a first film, wherein, in the step of (a), the raw material gas is adsorbed onto the substrate having the first film, wherein, in the step of (c), the plasma of the nitrogen gas is generated and reacted with the raw material gas adsorbed onto the substrate having the first film, and wherein the film forming method further comprises: (d) forming a second film on the substrate having the first film by atomic layer deposition by repeating the step of (a) and the step of (c).
3 . The film forming method of claim 2 , wherein the raw material gas is a silicon-containing gas.
4 . The film forming method of claim 3 , wherein the silicon-containing gas contains halosilane.
5 . The film forming method of claim 4 , wherein the first film is a carbon-containing film.
6 . The film forming method of claim 5 , wherein the second film is a silicon nitride film.
7 . The film forming method of claim 6 , wherein the substrate has a temperature in a range of −50 degrees C. to 700 degrees C.
8 . The film forming method of claim 3 , wherein the step of (a) includes: (e) adsorbing a first silicon-containing gas including a halogen-containing silane onto the substrate having the first film; and (f) adsorbing a second silicon-containing gas including a halogen-free silane onto the substrate having the first film.
9 . The film forming method of claim 8 , wherein, in the step of (a), the step of (e) and the step of (f) are alternately performed, and wherein the step of (b) and the step of (c) are further performed between the step of (e) and the step of (f).
10 . The film forming method of claim 1 , wherein the raw material gas includes one or more of Si, Al, Ti, Ta, B, W, and V.
11 . The film forming method of claim 1 , wherein the substrate has a temperature in a range of −50 degrees C. to 700 degrees C.
12 . A film forming method that forms a film on a substrate by plasma in a processing container including a stage configured to hold the substrate thereon, the film forming method comprising: (a) supplying a mixed gas of a raw material gas, a nitrogen gas (N 2 gas), and an inert gas to the processing container; and (b) generating plasma of the nitrogen gas by supplying a radio-frequency power of 180 MHz or higher and equal to or lower than 220 MHz to the processing container in which the nitrogen gas and the inert gas are supplied, wherein the substrate includes a first film, and wherein, in the step of (b), a second film is formed on the substrate having the first film by the generated plasma.
13 . The film forming method of claim 12 , wherein the raw material gas is a silicon-containing gas.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a U.S. National Stage Entry of International Patent Application No. PCT/JP2021/029695, filed Aug. 12, 2021, which claims the benefit of priority to Japanese Patent Application No. 2020-142859, filed Aug. 26, 2020, each of which is hereby incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates to a film forming method and a film forming apparatus. BACKGROUND In a semiconductor device manufacturing process, there is atomic layer deposition (ALD) in which a plurality of processing gases are switched to repeatedly stack thin unit films, which are approximately monomolecular layers, on a substrate. There is also plasma-enhanced atomic layer deposition (PEALD) using plasma during film formation. In addition, it has been proposed to form a silicon nitride layer on a wafer by PEALD using the plasma of a silicon-containing precursor and a nitrogen-containing reactant. PRIOR ART DOCUMENTS Patent Documents Patent Document 1: Japanese Laid-Open Publication No. 2018-050038 The present disclosure provides a film forming method and a film forming apparatus capable of suppressing damage caused by plasma. SUMMARY An embodiment of the present disclosure discloses a film forming method that forms a film on a substrate by plasma in a processing container including a stage configured to hold the substrate thereon, wherein the film forming method includes: (a) a step of supplying a raw material gas and a reaction gas as a processing gas to the processing container; and (b) a step of generating plasma of the processing gas using a radio-frequency power of 100 MHz or higher. According to the present disclosure, it is possible to suppress damage caused by plasma. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view illustrating an exemplary film-forming apparatus according to a first embodiment of the present disclosure. FIG. 2 is a flowchart illustrating an example of a film forming process in the first embodiment. FIG. 3 is a diagram illustrating an example of a film forming process sequence in the first embodiment. FIG. 4 is a diagram illustrating another example of a film forming process sequence in the first embodiment. FIG. 5 is a diagram illustrating an example of a film forming model of a silicon nitride film at a low temperature by PEALD. FIG. 6 is a diagram illustrating an example of precursors in a two-precursor process. FIG. 7 is a view illustrating an example of a wafer as a film formation target in the first embodiment. FIG. 8 is a diagram illustrating an example of experimental results in the first embodiment. FIG. 9 is a diagram illustrating another example of the film forming process sequence in a modification. FIG. 10 is a flowchart illustrating an example of a film forming process in a second embodiment. FIG. 11 is a view illustrating an example of a wafer as a film formation target in the second embodiment. FIG. 12 is a diagram illustrating an example of experimental results in the second embodiment. FIG. 13 is a diagram illustrating an example of experimental results in the second embodiment. DETAILED DESCRIPTION Hereinafter, embodiments of a film forming method and a film forming apparatus disclosed herein will be described in detail with reference to the drawings. The technology disclosed herein is not limited by the following embodiments. When a silicon nitride film is formed by PEALD, 400 kHz, 13.56 MHz, 27.12 MHz, and 60 MHz are usually used as the frequencies of radio-frequency power, and NH3 or amine is used as a nitriding gas. When NH3 or amine is used, H radicals are generated in plasma. H radicals damage metal films or resins. When a substrate having a film formed thereon contains these materials, the film quality of an underlying layer may be adversely affected. Therefore, it is expected to suppress damage caused by plasma and to reduce the influence of H radicals on film quality. First Embodiment [Overall Configuration of Film Forming Apparatus 100] FIG. 1 is a view illustrating an example of a film forming apparatus according to a first embodiment of the present disclosure. The film forming apparatus 100 illustrated in FIG. 1 is a capacitively coupled plasma processing apparatus. The film forming apparatus 100 includes a chamber 1, a susceptor 2 that horizontally supports a wafer W as an example of a target substrate in the chamber 1, and a shower head 3 configured to supply a processing gas into the chamber 1 in the form of a shower. In addition, the film forming apparatus 100 includes an exhauster 4 configured to evacuate the interior of the chamber 1, a processing gas supply mechanism 5 configured to supply a processing gas to the shower head 3, a plasma generating mechanism 6, and a controller 7. The chamber 1 is made of a metal such as aluminum, and has a substantially cylindrical shape. A carry-in/out port for carry-in/out of a wafer W (not illustrated) is formed in the sidewall of the chambe