Method of manufacturing photo-mask and photo-mask manufactured thereby
CA 1313792 C · Owner: Mieda, Michinobu · Inventors: Katayama, Hiroyuki; Inui, Tetsuya; Ohta, Kenji
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of manufacturing a photo-mask which, includes the steps of applying a resist film onto a substrate of quartz, glass and the like, subjecting the resist film to light exposure and development to form a fine resist pattern, etching the mask substrate covered by the fine resist pattern so as to cause a non-light transmitting thin film of Cr, Ta, etc. to adhere thereon by vapor deposition sputtering and the like, and removing the thin film on the resist pattern together with the resist film thereby-to, form the photo-mask. The disclosure is also directed to a photo-mask manufactured by the above method.
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted February 23, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 23, 2010.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.