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. 14, 2004
Filed:
Dec. 11, 2001
Shinichi Izuo, Tokyo, JP;
Hiroshi Ohji, Tokyo, JP;
Kazuhiko Tsutsumi, Tokyo, JP;
Patrick James French, Delft, NL;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An electrochemical etching system has an etching bath for holding an n-type silicon substrate with a first surface of the substrate in contact with hydrofluoric acid, an electrode positioned in the hydrofluoric acid, a power source having a positive pole connected to the silicon substrate and a negative pole connected to the electrode, and an illumination unit having a light source for illumination of a second surface of the silicon substrate. The illumination unit illuminates the second surface of the silicon substrate with an illumination intensity of 10 m W/cm or more. A ratio of a maximum illumination to a minimum illumination of the second surface of the silicon substrate is 1.69:1 or less. With the etching system, pores and/or trenches of a certain size and shape can be formed in an entire area of the silicon substrate having a diameter of more than three inches.