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:
Oct. 31, 2017
Filed:
Dec. 11, 2014
Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;
Akihiro Ishizuka, Sagamihara, JP;
Shinya Sasagawa, Chigasaki, JP;
Semiconductor Energy Laboratory Co., Ltd., Kanagawa-ken, JP;
Abstract
A manufacturing method forms an oxide insulating layer and a first plasma etching treatment forms a depressed portion therein. A second plasma etching treatment forms a trench including curved lower corner portions. An oxide semiconductor film is formed in contact with a bottom portion, the curved lower corner portions, and side portions of the trench. Source and electrodes are formed to be electrically connected to the oxide semiconductor film. A gate insulating layer is formed over the oxide semiconductor film and a gate electrode is formed over the gate insulating layer. The first plasma etching treatment is performed with a first bias power and a first power of a first power source, and the second plasma etching treatment is performed with a second bias power and a second power of a second power source, wherein the second bias power is lower than the first bias power.