Gas for selectively etching silicon nitride and process for selectively etching silicon nitride with the gas

• US 4,529,476 A
• Filed: 06/01/1984
• Issued: 07/16/1985
• Est. Priority Date: 06/01/1983
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd., Showa Denko KK (Resonac Holdings Corp.)
• Original Assignee: Hitachi, Ltd., Showa Denko KK (Resonac Holdings Corp.)
• Inventors: Kawakami, Hiroshi, Hashimoto, Norikazu, Kure, Tokuo, Kawamoto, Yoshifumi, Tachi, Shinichi, Takaichi, Tsuyoshi
• Primary Examiner(s): Powell, William A.
• Application Number:
  US06/616,114
• Time in Patent Office: 410 Days
• Field of Search: 156/643, 156/646, 156/653, 156/657, 156/659.1, 204/164, 204/192 E, 252/79.1, 427/38, 427/39
• US Class Current: 438/724
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/5346 Dry etching
• CPC Class Codes: C04B 41/91 involving the removal of part of the materials of the treated articles, e.g. etching
• CPC Class Codes: C09K 13/08 containing a fluorine compound
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

A dry-etching gas suitable for selective etching of silicon nitride and a process for selectively dry-etching silicon nitride with the dry-etching gas are disclosed. Silicon nitride can be dry-etched with a higher selectivity or at a higher etching rate than silicon dioxide and silicon, and a process for fabricating semi-conductor devices can be simplified and devices with a novel structure can be realized.

Claims

1. A gas for selectively etching silicon nitride, which comprises a composition consisting of C, H and F atom species and having a ratio of F to H by atom of not more than 2.

2. A gas according to claim 1, wherein the gas has a carbon number of not more than 3.

3. A gas according to claim 1 or 2, wherein the gas is at least one member selected from the group consisting of CH₂ F₂, CH₃ F, C₂ H₅ F, C₂ H₄ F₂, C₂ H₃ F₃, C₂ H₂ F₄, C₃ H₇ F, C₃ H₆ F₂, C₃ H₅ F₃, C₃ H₄ F₄ and C₃ H₃ F₅.

4. A process for etching an article by contact of the article with a plasma of a reacting gas, which comprises selectively etching silicon nitride as the article with a gas consisting of C, H and F atom species and having a ratio of F to H by atom of not more than 2 as the reacting gas.

5. A process according to claim 4, wherein the reacting gas has a carbon number of not more than 3.

6. A process according to claim 4 or 5, wherein the reacting gas is at least one member selected from the group consisting of CH₂ F₂, CH₃ F, C₂ H₅ F, C₂ H₄ F₂, C₂ H₃ F₃, C₂ H₂ F₄, C₃ H₇ F, C₃ H₆ F₂, C₃ H₅ F₃, C₃ H₄ F₄ and C₃ H₃ F₅.

7. A process according to claim 4, wherein the etching is carried out in a reactive sputter etching apparatus in a parallel plate type.

8. A process according to claim 7, wherein the reacting gas has a pressure of 0.01-0.1 Torr.

9. A process according to claim 4, wherein at least one of silicon dioxide film and polycrystalline silicon film, and a film of the silicon nitride are exposed to surface.

10. A process according to claim 9, where the film of the silicon nitride is etched by masking the silicon dioxide film or the polycrystalline silicon film or both.

11. A process according to claim 4, wherein the film of the silicon nitride is formed on a silicon substrate, the polycrystalline silicon film or the silicon dioxide film.

12. A process according to claim 4, wherein the reacting gas is mixed with at least one member selected from the group consisting of N₂, O₂, H₂ and He.

13. A process according to claim 4, wherein the reacting gas is a mixture of at least one of CF₄ and CHF₃, and H₂.