Self-aligned phase-shifting mask
CA 2082869 A1 · Owner: Young, Malcolm A. · Inventors: Young, Malcolm A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract A phase-shifting mask with self-aligned spacers of phase-shift material adjacent to the edges of the opaque mask pattern and a method for making the same is disclosed. The method of the invention deposits a blanket layer of an appropriate phase-shift material over a transparent mask substrate having a patterned opaque layer followed by a removal step which forms the spacers. The mask is preferably comprised of a quartz substrate covered with a patterned chrome layer fabricated following the normal inspection and repair procedure. A layer of phase-shift material is then blanket deposited. The thickness and index of refraction of the phase-shift material is chosen to provide a …
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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
- Filed November 13, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 13, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 13, 2014.
- 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.