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:
Jul. 25, 2000
Filed:
May. 13, 1997
Applicant:
Inventors:
Satoru Ohkubo, Tokyo, JP;
Kensuke Kasahara, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
438745 ; 438752 ; 438753 ;
Abstract
A compound semiconductor wafer is dipped into water at a temperature of 5.degree. C. for about 10 seconds to preliminarily adjust to a temperature substantially equal to a temperature of etching agent. Next, with taking a photoresist as a mask, etching is performed at 5.degree. C. employing a mixture of 50 wt % of citric acid solution and 30 wt % of hydrogen peroxide solution in a volume ratio of 3:1. Thereafter, gate metal is deposited, and the mask and excessive metal are removed by a lift-off or other method to fabricate a semiconductor device.