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. 19, 1995
Filed:
May. 12, 1994
Chi-Min Yuan, Austin, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method of determining quantitatively the exposure levels for photoresists in semiconductor photolithography employs a specially designed grating pattern on a mask. The mask is first used to expose a series of LIM image gratings of different dosages. Then a normal plane wave at a longer wavelength is incident on these gratings one by one, and some nonzero order diffraction efficiency of the grating is measured to determine quantitatively the correct dosage to be used. This method can make a determination of exposure dosage, without knowledge of underlying film thickness and refractive index, and handle either resist thickness change or underlying film thickness/refractive index change or both.