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:
Mar. 29, 2005
Filed:
Sep. 26, 2000
Wanqing Cao, Portland, OR (US);
Guo-qiang Lo, Portland, OR (US);
Shih-ked Lee, Hillsboro, OR (US);
Hongyong Xue, Portland, OR (US);
Wanqing Cao, Portland, OR (US);
Guo-Qiang Lo, Portland, OR (US);
Shih-Ked Lee, Hillsboro, OR (US);
Hongyong Xue, Portland, OR (US);
Integrated Device Technology, Inc., Santa Clara, CA (US);
Abstract
An improved method is provided for etching back a tungsten layer that overlies a titanium nitride adhesion layer on a semiconductor structure. This method includes the steps of: (1) performing a first plasma etchback of the tungsten layer for a first predetermined time period, such that a thin layer of tungsten remains over the adhesion layer at the end of the first plasma etchback, (2) actively or passively cooling the resulting semiconductor structure to a temperature of 35° C. or lower, and then (3) performing a second plasma etchback of the tungsten layer until an endpoint is detected, thereby exposing the adhesion layer. Cooling the semiconductor structure prior to the second plasma etchback ensures that the titanium nitride adhesion layer is at a relatively low temperature during the second plasma etchback. The titanium nitride adhesion layer etches significantly slower at lower temperatures, thereby making it easier to stop the second plasma etchback on the adhesion layer.