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:
Sep. 02, 2003
Filed:
May. 22, 2002
Yukihisa Wada, Kyoto, JP;
Satoshi Kume, Kanagawa, JP;
Other;
Abstract
On the sides of a gate electrode, layered-film sidewalls are formed which includes a first oxide film such as an NSG film or a TEOS film and a second oxide film such as a BPSG film or a PSG film. After the layered-film sidewalls are used as a mask for forming source and drain regions of a MIS transistor, the second oxide film of the sidewalls is selectively removed. At the removal, wet etching is performed with an aqueous solution containing hydrofluoric acid, and acetic acid or isopropyl alcohol. This makes etching selectivity between oxide films higher and removes only the upper second oxide film. As a result, in the formation of two types of oxide films which differ in their etching properties, the etching selectivity can be prevented from deteriorating.