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. 21, 2001
Filed:
Mar. 29, 1999
Taiwan Semiconductor Manufacturing Company, Hsin-Chu, TW;
Abstract
A method of using a monitor wafer to monitor the shielding of alignment marks during material deposition steps. The alignment marks are shielded using shielding tabs attached to the clamp ring used to clamp the wafer during deposition of a layer of material. An oxide monitor wafer, having the same size and shape of product wafers, has monitor marks formed thereon. The center of the monitor marks has the same location on the monitor wafer as the alignment marks have on the product wafers. The monitor wafer is subjected to the same processing steps as the product wafers through the step of material deposition. The clamp ring is removed from the monitor wafer and the distance from the center of the monitor marks and the edge of the deposited material is determined. The monitor marks are formed so that the distance from the center of the monitor marks and the edge of the deposited material can be determined by direct observation of the monitor marks. The monitor wafers are processed after adjustments to or maintenance on equipment or after a fixed number of product wafers are processed.