The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 12, 1999
Filed:
Jul. 03, 1997
Chunshi Cui, Santa Clara, CA (US);
Robert W Wu, Pleasanton, CA (US);
Gerald Zheyao Yin, Cupertino, CA (US);
Applied Materials, Inc., Santa Clara, CA (US);
Abstract
A low-temperature process for selectively etching oxide with high selectivity over silicon in a high-density plasma reactor. The principal etching gas is a hydrogen-free fluorocarbon, such as C.sub.2 F.sub.6 or C.sub.4 F.sub.8, to which is added a silane or similar silicon-bearing gas, e.g., the monosilane SiH.sub.4. The fluorocarbon and silane are added in a ratio within the range of 2 to 5, preferably 2.5 to 3. The process provides high polysilicon selectivity, high photoresist facet selectivity, and steep profile angles. Selectivity is enhanced by operating at high flow rates. Silicon tetrafluoride may be added to enhance the oxide etching rate. The process may operate at temperatures of chamber parts below 180.degree. C. and even down to 120.degree. C. The process enables the fabrication of a bi-level contact structure with a wide process window.