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:
May. 08, 2001
Filed:
Sep. 23, 1998
Akihiko Furukawa, Hyogo, JP;
Yoshikazu Yoneda, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of manufacturing a semiconductor device is provided in which a semiconductor device including a plurality of FETs having different threshold voltages and gate insulating films with different film thicknesses can be manufactured in a simplified process. Specifically, a first gate insulating film is formed on the main surface of a semiconductor substrate. On the first gate insulating film, a first protection film is formed. In regions A and B in each of which an FET having a second gate insulating film with a film thickness different from that of the first gate insulating film is to be formed, the first gate insulating film and the first protection film are removed to expose the surface of the semiconductor substrate. At the same time, the first protection film is left in regions other than the regions A and B. Using the first protection film as a mask, an impurity is implanted into the semiconductor substrate in the regions A and B.