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:
Jan. 28, 2014
Filed:
Jun. 14, 2011
Shinya Sasagawa, Chigasaki, JP;
Hitoshi Nakayama, Atsugi, JP;
Masashi Tsubuku, Atsugi, JP;
Daigo Shimada, Atsugi, JP;
Shinya Sasagawa, Chigasaki, JP;
Hitoshi Nakayama, Atsugi, JP;
Masashi Tsubuku, Atsugi, JP;
Daigo Shimada, Atsugi, JP;
Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;
Abstract
When a transistor including a conductive layer having a three-layer structure is manufactured, three-stage etching is performed. In the first etching process, an etching method in which the etching rates for the second film and the third film are high is employed, and the first etching process is performed until the first film is at least exposed. In the second etching process, an etching method in which the etching rate for the first film is higher than that in the first etching process and the etching rate for a 'layer provided below and in contact with the first film' is lower than that in the first etching process is employed. In the third etching process, an etching method in which the etching rates for the first to the third films are higher than those in the second etching process is preferably employed.