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:
Aug. 20, 2002
Filed:
Apr. 18, 2001
Shinji Makikawa, Annaka, JP;
Hiroshi Aoi, Annaka, JP;
Masaaki Shirota, Annaka, JP;
Seiki Ejima, Kita-Gun, JP;
Shin-Etsu Chemical Co., Ltd, Tokyo, JP;
Abstract
A method of making a high quality optical waveguide substrate is provided, in which the surface of a silicon substrate is oxidized through relatively large thickness and no foreign matter particles are adhered on the surface thereof. The silicon substrate to form a quartz film for the optical waveguide is mounted on a carbon contained ceramics sample base and is inserted into a carbon contained ceramics furnace core tube of which its external circumference is arranged in a heating furnace. When the inside of the furnace core tube is heated to 200 to 600° C. by the heating furnace, an oxidant gas for the silicon substrate surface is introduced, then by further heating up to 1200 to 1350° C., the silicon surface is thus oxidized.