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:
May. 11, 1999
Filed:
Dec. 23, 1997
Xian J Ning, Mohegan Lake, NY (US);
Rainer Florian Schnabel, Wappingers Falls, NY (US);
Siemens Aktiengesellschaft, Munich, DE;
Abstract
Methods for detecting under-etched vias, spaces, or under-polished portions in a wafer stack are disclosed. The wafer stack comprises a dielectric layer disposed on a metal layer. The dielectric layer has a plurality of vias etched therein. The wafer stack, including the plurality of vias, is exposed to an etchant which is configured to etch the metal layer at a substantially faster rate than the dielectric layer. As a result, cavities are formed in the metal layer below properly-etched vias. Then, the vias in the wafer stack are optically inspected to detect and identify under-etched vias, which reflect more light than the cavities etched into the metal layer.