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:
Dec. 30, 1997
Filed:
May. 08, 1995
Mark D Kellam, Chapel Hill, NC (US);
Gershon Kedem, Chapel Hill, NC (US);
Astarix Inc., , US;
Abstract
A photoresist (18) is exposed through a design-independent high resolution reticle (20), producing a high resolution image of exposed resist (18A). Photoresist (18) is exposed for the second time through a design-specific low-resolution reticle (24), exposing selected portions (18D) of previously unexposed resist. The remaining portions (18B) of previously unexposed resist form a design-dependent high resolution image. After development of photoresist (18), its unexposed portions (18B) are removed, producing openings (26) in photoresist (18), that can be transferred to underlying material (36), for example by etching openings in that underlying material (36), thereby transferring the design-dependent high-resolution image to it. Since the design-independent high resolution reticle (20) can be prefabricated ahead of time and used to produce many designs with different functions, the above double-exposure method is suitable for fabricating design-specific high resolution features, e.g., contacts (vias) between conducting layers, within time and at the approximate cost required to fabricate and process a low resolution image. Several variants of the basic method are possible.