Apparatus for imaging a mask pattern on a substrate
CA 1232981 A · Owner: N.V.Philips'Gloeilampenfabrieken · Inventors: Van Der Werf, Jan E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
PHN. 11.053 15, ABSTRACT:, A pre-alignment system of an apparatus for imaging a mask pattern on a substrate is described. The pre-alignment system comprises two optical imaging systems for imaging two alignment marks provided on the substrate for the purpose of fine-alignment onto two radiation-sensitive detectors, the combined output signals of the subdetectors of each detector being a measure of the alignment of the associated alignment mark relative to a detector. me alignment marks are preferably phase gratings and the imaging systems are preferably interference-contrast microscopes.
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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 16, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 16, 2005.
- 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.