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:
Nov. 14, 1995
Filed:
Apr. 28, 1994
Jonathan D Chapple-Sokol, Poughkeepsie, NY (US);
Louis L-C. Hsu, Fishkill, NY (US);
Paul J-M. Tsang, Poughkeepsie, NY (US);
Chi-Min Yuan, Austin, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A subtractive method for making a Levenson type lithographic phase shift mask using a sacrificial etch monitor film in which some of the monitor film is left standing on the opaque portions of the mask. The monitor film otherwise is consumed when it is simultaneously etched with selected portions of the mask substrate to produce recesses of desired depth in the substrate. The etching is stopped upon detecting that the etched monitor film is completely consumed. The technique also is adapted for the fabrication of a RIM type lithographic phase shift mask combined with the Levenson type phase shift mask in the same mask. The technique further is adapted to include 90 degree shift transitions at the end of the Levenson line-space pairs of the mask. The monitor film left standing on the opaque portions of the mask provides self-aligned phase error correction to offset sidewall scattering in the Levenson type mask.