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. 18, 2001
Filed:
Jul. 10, 1997
Yoshiaki Nakayama, Okazaki, JP;
Shoji Miura, Nukata-gun, JP;
Denso Corporation, Kariya, JP;
Abstract
A semiconductor wafer in which black silicon does not form during trench etching even when side rinsing is carried out during a photolithography process. In an embedded oxide film interposed between first and second semiconductor wafers of a bonded SOI wafer, the film thickness of a peripheral part thereof is made greater than a predetermined thickness Dsio so that it functions as an oxide film for etching prevention. When side rinsing is carried out in a resist coating process to form an opening in an oxide film for masking use in trench etching, the oxide film for masking use at the periphery is also etched during formation of the opening. Due to over-etching at that time, the oxide film for etching prevention is etched by a film thickness d,. During trench etching also, the oxide film for etching prevention is etched by a film thickness d,. Accordingly, if the film thickness Dsio of the oxide film for etching prevention is set to be greater than the film thickness d,+d,, because an oxide film remains at the final stage, the formation of black silicon can be prevented.