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:
Mar. 08, 1994
Filed:
Jul. 02, 1992
Kevin G Kemp, Austin, TX (US);
Bernard J Roman, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Integrated circuits with small feature sizes are obtained using a phase shifting mask which has reduced back reflection and improved optical contrast. These improvements result from reduced etching of the chrome and chrome oxide layers on the phase shifting mask. In one embodiment, the phase shifting mask is formed by depositing an image reversible photoresist layer (22) which overlies the optical mask (18). Forming a first exposed region (24) and an unexposed region (26) in the image reversible photoresist layer (22). Treating the first exposed region (24) to form a hardened first exposed region. Forming a second exposed region (30) within the remaining portion of the unexposed region (26) by exposing the back surface (16) of the substrate (12) to an optical illumination source. Removing the second exposed region (30) to uncover a portion (32) of the substrate (12) and to form an etch mask (34). The uncovered portion (32) of the substrate (12) is etched to form a trench region (38).