CN-121986581-A - Etching method and etching apparatus

CN121986581ACN 121986581 ACN121986581 ACN 121986581ACN-121986581-A

Abstract

The etching method includes a first gas supply step of supplying a fluorine-containing gas into a process container for storing a substrate on which a silicon oxide film is formed in a first period, a second gas supply step of supplying an alkaline gas into the process container in a second period including a common supply period overlapping with the first period, and a first gas exhaust step of exhausting gas from the process container so that the pressure in the process container in the common supply period becomes a first pressure of 50Torr or more in order to perform etching of the silicon oxide film by using the fluorine-containing gas and the alkaline gas.

Inventors

TAUCHI KEITO
JIN CHENGMIN
YOSHIAKI OKAMOTO
Kotoh Shusuke
Nandabe sho

Assignees

东京毅力科创株式会社

Dates

Publication Date: 20260505
Application Date: 20241009
Priority Date: 20231016

Claims (13)

1. An etching method comprising the steps of: a first gas supply step of supplying a fluorine-containing gas into a process container for storing a substrate having a silicon oxide film formed thereon during a first period; A second gas supply step of supplying an alkaline gas into the process container during a second period including a common supply period overlapping with the first period, and And a first evacuation step of evacuating the process chamber so that the pressure in the process chamber during the common supply period becomes a first pressure greater than 50Torr in order to etch the silicon oxide film by using the fluorine-containing gas and the alkaline gas.
2. The etching method according to claim 1, wherein, The fluorine-containing gas is hydrogen fluoride gas and the alkaline gas is ammonia gas.
3. The etching method according to claim 2, wherein, The etching method includes a second evacuation step of evacuating the processing container after the first evacuation step so that the interior of the processing container has a second pressure of 50Torr or less lower than the first pressure.
4. The etching method according to claim 3, wherein, The treatment vessel is connected to an upstream end of a first exhaust path, a downstream end of the first exhaust path is connected to a first exhaust mechanism, a first valve and a second exhaust mechanism are provided in this order on the first exhaust path toward a downstream side, An upstream side of the first valve in the first exhaust path and a downstream side of the second exhaust mechanism in the first exhaust path are connected to an upstream end and a downstream end of a second exhaust path provided with a second valve, The second exhaust process includes: A first exhausting step of closing the first valve to exhaust the inside of the processing container by the first exhausting means, and And a post-evacuation step of closing the second valve after the preceding evacuation step to evacuate the processing container through the first evacuation mechanism and the second evacuation mechanism.
5. The etching method according to claim 3, wherein, The etching method includes a continuous etching step of continuing the etching in a state in which the supply of the fluorine-containing gas and the alkaline gas into the processing container is stopped, after the first exhausting step and before the pressure in the processing container is continuously reduced to the second pressure.
6. The etching method according to claim 5, wherein, The continuous etching step is performed for a longer period of time than a period of time during which one of a fluorine-containing gas and an alkaline gas is supplied into the processing container.
7. The etching method according to claim 3, wherein, One of the first period and the second period starts before the other of the first period and the second period, and is longer than the other of the first period and the second period.
8. The etching method according to claim 7, wherein, The period of one of the first period and the second period is a first period.
9. The etching method according to claim 1, wherein, The first pressure is 70 Torr-100 Torr.
10. The etching method according to claim 1, wherein, The etching method includes a step of setting the temperature of the substrate in the common supply period to 100 ℃ or higher.
11. The etching method according to any one of claims 1 to 10, wherein, The silicon oxide film includes a thermal oxide film.
12. The etching method according to claim 11, wherein, The silicon oxide film includes the thermal oxide film and a silicon oxide film of a different kind from the thermal oxide film.
13. An etching apparatus includes: a processing container for storing a substrate on which a silicon oxide film is formed; a first gas supply unit configured to supply a fluorine-containing gas into the process container during a first period; A second gas supply unit configured to supply an alkaline gas into the process container during a second period including a common supply period overlapping with the first period, and And a gas exhaust unit configured to exhaust the interior of the processing container so that the pressure in the processing container during the common supply period becomes a first pressure greater than 50Torr in order to etch the silicon oxide film by using the fluorine-containing gas and the alkaline gas.

Description

Etching method and etching apparatus Technical Field The present disclosure relates to an etching method and an etching apparatus. Background In the production of a semiconductor device, a silicon oxide film formed on the surface of a semiconductor wafer (hereinafter, referred to as a wafer) as a substrate is sometimes etched. Patent document 1 describes a technique in which HF gas and NH 3 gas are supplied to a silicon oxide film on the surface of a wafer to generate ammonium silicofluoride (Ammonium Fluoro Slicate: AFS) as a reaction product, and then the wafer is heated to vaporize the AFS, thereby performing the etching. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2021-180281 Disclosure of Invention Problems to be solved by the invention The present disclosure provides a technique capable of etching a silicon oxide film at a desired etching rate. Solution for solving the problem The etching method includes a first gas supply step of supplying a fluorine-containing gas into a process container for storing a substrate having a silicon oxide film formed thereon during a first period; A second gas supply step of supplying an alkaline gas into the process container during a second period including a common supply period overlapping with the first period, and And a first evacuation step of evacuating the process chamber so that the pressure in the process chamber during the common supply period becomes a first pressure greater than 50Torr in order to etch the silicon oxide film by using the fluorine-containing gas and the alkaline gas. ADVANTAGEOUS EFFECTS OF INVENTION The present disclosure enables etching of a silicon oxide film at a desired etching rate. Drawings Fig. 1 is a longitudinal cross-sectional side view of an etching apparatus according to one embodiment of the present disclosure. Fig. 2 is an explanatory diagram showing an operation of the process in the etching apparatus. Fig. 3 is an explanatory diagram showing an operation of the process in the etching apparatus. Fig. 4 is an explanatory diagram showing an operation of the process in the etching apparatus. Fig. 5 is an explanatory diagram showing an operation of the process in the etching apparatus. Fig. 6 is an explanatory diagram showing an operation of the process in the etching apparatus. Fig. 7 is a graph showing supply and shut-off of gas to the process container and pressure changes in the process container. Fig. 8 is a longitudinal cross-sectional side view of a wafer before and after etching. Fig. 9 is a graph showing the results of the evaluation test. Fig. 10 is an explanatory diagram showing an example of processing in the evaluation test. Fig. 11 is an explanatory diagram showing an example of processing in the evaluation test. Fig. 12 is an explanatory diagram showing an example of processing in the evaluation test. Detailed Description An embodiment of the etching method of the present disclosure will be described. Fig. 1 is a longitudinal sectional side view of an etching apparatus 1 for carrying out the etching method. The etching apparatus 1 etches a film formed on the surface of a wafer W as a substrate in a non-plasma atmosphere of a vacuum atmosphere. The films to be etched are a thermal oxide film 11 and a silicon oxide film 12. The thermal oxide film 11 is a silicon oxide film obtained by heating a silicon film at a temperature of 700 ℃ or higher in an oxygen atmosphere or a water vapor atmosphere which is a non-plasma atmosphere. The silicon oxide film 12 is a silicon oxide film of a different kind from the thermal oxide film 11. Specifically, a silicon oxide film formed by CVD (Chemical Vapor Deposition: chemical vapor deposition) or ALD (Atomic Layer Deposition: atomic layer deposition), a silicon oxide film containing an additive element such as a PSG (phosphous SILICATE GLASS: phosphosilicate glass) film or a BSG (Borosilicate Glass: borosilicate glass) film, and a film obtained by oxidizing silicon in a plasma environment correspond to the silicon oxide film 12. Film formation by CVD or ALD includes both film formation in a plasma environment and film formation in a non-plasma environment. Further, as a silicon oxide film formed by CVD or ALD, there is a silicon oxide film formed by supplying TEOS (tetra ethoxy silane: tetraethoxysilane) gas as a film forming gas to the wafer W, and this silicon oxide film is sometimes referred to as a TEOS film hereinafter. In order to avoid confusion with the thermal oxide film 11, the silicon oxide film 12 may be hereinafter referred to as a non-thermal oxide film 12. It is desirable to increase the etching rate (etching amount per unit time) of the thermal oxide film 11, and it is sometimes required to have an etching rate larger than that of the non-thermal oxide film 12. The etching apparatus 1 is configured to cope with this requirement. In the etching process in the etching apparatus 1, HF (hydrogen fluoride) gas is us