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. 14, 2001
Filed:
Feb. 25, 1999
Roger M. Terry, Allen, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A method and system of measuring misalignment between two levels wherein there is provided a first grating pattern (,) on a first layer (,) and a second grating pattern (,) on a second layer (41) capable of providing Moire fringes when disposed over the first grating pattern and which is disposed over the first grating pattern whereby the first and second grating patterns are capable of providing Moire fringes. Misalignment of the first layer relative to the second layer is measured from the position of the Moire fringe provided by the first and second grating patterns either visually or by optical instrumentation. The second layer is preferably transparent. The first grating pattern comprises a first group of plural sets of lines (,) , each of the lines of each of the sets being parallel to each other and extending across first imaginary straight lines, a second group of plural sets of lines (,) each of the lines of each set of lines of the second group being parallel to each other and each extending across a second imaginary straight line, each second imaginary line being parallel to a different one of the first imaginary lines, the second grating pattern being substantially identical to that of the first layer with the imaginary lines overlapping except that overlapping sets of lines are at an angle to each other different from being parallel and preferably overlap at an angle of less than about 60 degrees. Preferably, the first imaginary straight lines numbers four lines in the shape of a rectangle.