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:
Aug. 23, 2005
Filed:
May. 29, 2003
Hitoshi Shiraishi, Tokyo, JP;
Kenichi Hayashi, Tokyo, JP;
Naoto Hirano, Tokyo, JP;
Atsushi Yamamoto, Tokyo, JP;
Hitoshi Shiraishi, Tokyo, JP;
Kenichi Hayashi, Tokyo, JP;
Naoto Hirano, Tokyo, JP;
Atsushi Yamamoto, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A semiconductor film serving as an active region of a thin film transistor and an upper oxide film protecting the semiconductor film are dry etched to form the active region. In this case, a fluorine-based gas is used as the etching gas, and the etching gas is switched from the fluorine-based gas to a chlorine-based gas at a point of time when a lower oxide film as an underlying film of the semiconductor film is exposed. As the fluorine-based gas, a mixed gas of CFand Ois used, and suitably, a gas ratio of CFand Oin the mixture gas is set at 1:1, and the dry etching is performed therefor. By this etching, a side face of a two-layer structure of the semiconductor film and upper oxide film is optimally tapered, and a crack or a disconnection is prevented from being occurring in a film crossing over the two-layer structure.