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. 22, 2000
Filed:
Nov. 19, 1998
Paul McKay Moore, San Bruno, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
Reflectance of a silicon light valve is preserved by eliminating bowing in the wafer and by retaining the pad etch photoresist mask on the wafer until insertion of LC material. Wafer bowing is eliminated by performing backside etching to remove polysilicon and oxide accumulated during previous polysilicon deposition steps. The pad etch photoresist mask serves as passivation during wafer transport and testing before liquid crystal material is inserted. The pad etch photoresist mask is removed during the cleaning step that is required prior to insertion of LC material. Elimination of the redundant pad etch photoresist mask stripping step spares the metal electrodes of the precursor light valve structure from roughness and loss of reflectance that would be caused by the extra cleaning step.