Control of etch rate ratio of SiO.sub.2 /photoresist for quartz planarization etch back process

• US 4,511,430 A
• Filed: 01/30/1984
• Issued: 04/16/1985
• Est. Priority Date: 01/30/1984
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chen, Lee, Mathad, Gangadhara S.
• Primary Examiner(s): Powell, William A.
• Application Number:
  US06/575,118
• Time in Patent Office: 442 Days
• Field of Search: 156/643, 156/646, 156/657, 156/659.1, 156/668, 252/79.1, 204/192 E, 427/38, 427/39
• US Class Current: 438/723
• CPC Class Codes: H01L 21/31055 the removal being a chemical etching step, e.g. dry etching etching per se H01L21/311
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31138 by dry-etching

Abstract

A method of controlling the etch rate ratio of SiO₂ /photoresist (PR) in a quartz planarization etch back process involves etching with a gaseous mixture containing CF₄ and either CHF₃ or C_x F_y with x>1 or O₂. The preferred SiO₂ /PR ratio of 1.2±0.1 is obtained by either adding CHF₃ to decrease the etch rate of the PR or by adding O₂ to increase the etch rate of the PR.

Claims

1. A method for uniformly etching a surface which includes both silicon dioxide and an organic polymer material comprising the steps of

contacting said surface with a reactive etching plasma which contains CF₄ and a gas taken from the group consisting of CHF₃ and C_x F_y with x>

1 to cause the structure formed by said etching step to be substantially planar and have an etch rate ratio of 1.2±

0.1.

2. A method as described in claim 1 whereby said etching plasma contains CHF₃.

3. A method as described in claim 2 whereby the gaseous mixture contains 0.5 to 5.0% CHF₃.

4. A method as described in claim 1 including the step of evacuating said structure to a pressure of not less than 500 microns of mercury.

5. A method as described in claim 1 whereby said reactive etching plasma contains oxygen.

6. A method as described in claim 5 whereby the reactive etching plasma contains 0.5 to 10 volume % O₂.