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. 03, 1999
Filed:
Nov. 26, 1997
Abstract
A phase-shifting mask structure has a base plate, a pattern zone on the base plate and a peripheral region on the periphery of the base plate around the pattern zone. The peripheral region and the pattern zone further have a plurality of alignment-checking patterns and alignment slits. Each alignment-checking pattern has a first pattern of light-blocking thin films and a second pattern of light-penetrating thin films. Similarly, each alignment slit has a third pattern of light-blocking thin films and a fourth pattern of light-penetrating thin films. In this invention, absolute light-blocking thin films are used in the light-blocking portions of the alignment-checking pattern and the alignment slits instead of the semi-transparent thin films in a conventional system. Thus, alignment checking errors due to the distortion of fiducial marks are minimized, and mask layers are more precisely aligned.