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. 05, 2009
Filed:
May. 11, 2007
Shu-chun Chan, Hsinchu, TW;
Jung-ching Chen, Hsinchu, TW;
Shyan-yhu Wang, Hsinchu County, TW;
United Microelectronics Corp., Hsinchu, TW;
Abstract
A method of manufacturing gate oxide layers with different thicknesses is disclosed. The method includes that a substrate is provided first. The substrate has a high voltage device region and a low voltage device region. Then, a high voltage gate oxide layer is formed on the substrate. Afterwards, a first wet etching process is performed to remove a portion of the high voltage gate oxide layer in the low voltage device region. Then, a second wet etching process is performed to remove the remaining high voltage gate oxide layer in the low voltage device region. The etching rate of the second wet etching process is smaller than that of the first wet etching process. Next, a low voltage gate oxide layer is formed on the substrate in the low voltage device region.