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:
Apr. 22, 2003
Filed:
May. 09, 2002
Applicant:
Inventor:
Sadaaki Masuoka, Tokyo, JP;
Assignee:
NEC Electronics Corporation, Kawasaki, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 1/8234 ;
U.S. Cl.
CPC ...
H01L 1/8234 ;
Abstract
A method for forming three gate oxide films having different thicknesses in first through third circuit areas, respectively. The method includes the consecutive steps of forming a first gate oxide film having a largest thickness in all the areas, removing the first gate oxide film and forming a second gate oxide film having a second largest thickness in the second circuit area, and removing the first gate oxide and forming a third gate oxide film having a smallest thickness in the third circuit area. The resultant gate oxide films have accurate thicknesses.