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:
Jul. 09, 1996
Filed:
Sep. 26, 1995
Mamiko Nakanishi, Itami, JP;
Yasutaka Kohno, deceased, late of Saijyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A method for producing a semiconductor device includes preparing a semi-insulating substrate having an active layer, depositing a first insulating film on the active layer and forming two first openings in the first insulating film, depositing a second insulating film on the first insulating film filling the first openings and make a flat surface with the surface of the first insulating film, removing a portion of the first insulating film between the first openings to form a second opening, etching the active layer through the second opening formed by the removal of the first insulating film, removing parts of the second insulating film on opposite sides of the first insulating film from the active layer to form a third opening, and etching the active layer through the third opening formed by removal of the second insulating film to form a double-stage recess. The widths of the first and second stage recesses are determined by the pattern of the first insulating film and the patterns of the first and second insulating films, respectively, so that only one alignment step is sufficient and the positions and the widths of the recess are easily controlled, enhancing the degree of freedom in the recess width.