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. 12, 2002
Filed:
Jul. 06, 2000
Sang-In Han, Phoenix, AZ (US);
Pawitter Mangat, Gilbert, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A method and apparatus for determining stress levels of membrane masks that may be used in membrane-based lithographic techniques is presented. A piezoelectric plate ( ) is used to induce vibrations into the membrane mask ( ), where the frequency and amplitude of the vibrations induced in the membrane layer ( ) are optically sensed. By comparing the stimulus applied to the piezoelectric plate ( ) with the response sensed optically in a gain phase analyzer ( ), a frequency graph ( ) associated with the membrane layer ( ) is constructed such that resonant frequencies are easily determined. These resonant frequencies can then be used to calculate the stress associated with the membrane layer ( ).