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:
Apr. 13, 2004
Filed:
Oct. 17, 2002
Atsushi Kanda, Suwa, JP;
Yasushi Haga, Sakata, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
Among first and second oxide films and formed on a substrate , the oxide film in a low-breakdown-voltage transistor area LV is all etched off, while the whole surface of the oxide film in a high-breakdown-voltage transistor area HV is left intact. A sixth oxide film for defining side walls is subsequently formed on the whole surface of the substrate in a greater thickness of approximately 2000 angstrom than a standard thickness. Over-etching of the sixth oxide film defines side walls SW. Non-required portions of the oxide film are then etched off with a resist R A. This causes a drain-source forming region, which is expected to form a drain area and a source area, to be open in an element forming region in a high-breakdown-voltage nMOS area HVn. The resist R A is not removed but is used continuously, and an n-type impurity ion is implanted into the open drain-source forming region. This arrangement enables both a high-breakdown-voltage MOS transistor and a low-breakdown-voltage MOS transistor to be formed efficiently on an identical substrate without damaging the characteristics of the respective MOS transistors.