Method for manufacturing thin film transistor using multi-tone mask

Patent metadata

Field	Value
Publication number	US-8980685-B2
Application number	US-201414191853-A
Country	US
Kind code	B2
Filing date	Feb 27, 2014
Priority date	Oct 24, 2008
Publication date	Mar 17, 2015
Grant date	Mar 17, 2015

Abstract

An object is to manufacture a semiconductor device including an oxide semiconductor at low cost with high productivity in such a manner that a photolithography process is simplified by reducing the number of light-exposure masks In a method for manufacturing a semiconductor device including a channel-etched inverted-staggered thin film transistor, an oxide semiconductor film and a conductive film are etched using a mask layer formed with the use of a multi-tone mask which is a light-exposure mask through which light is transmitted so as to have a plurality of intensities. In etching steps, a first etching step is performed by wet etching in which an etchant is used, and a second etching step is performed by dry etching in which an etching gas is used.

First claim

What is claimed is:

1. A method for manufacturing a semiconductor device, comprising:
forming a gate electrode layer over an insulating surface, wherein the gate electrode layer comprises a stack of a first layer comprising Ti and a second layer comprising Cu;
forming a gate insulating layer over the gate electrode layer, wherein the gate insulating layer comprises a stack of a silicon nitride layer and a first silicon oxide layer, and the silicon nitride layer covers the second…

Assignees

• Semiconductor Energy Lab

Inventors

• Suzawa Hideomi
• Sasagawa Shinya
• Muraoka Taiga
• Ito Shunichi
• Hosoba Miyuki

Classifications

• H10D30/0312

  Electricity · mapped topic

• H10D30/6755

  Electricity · mapped topic

• H10D30/6715

  Electricity · mapped topic

• H10D99/00 Primary

  Electricity · mapped topic

• H10D86/0231

  Electricity · mapped topic