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. 18, 2010
Filed:
Apr. 02, 2008
Baher S. Haroun, Allen, TX (US);
Gaurav Chandra, Richardson, TX (US);
Vijaya Bhaskar Rentala, Plano, TX (US);
Venkatesh Srinivasan, Dallas, TX (US);
Hisashi Shichijo, Plano, TX (US);
Krishnaswamy Nagaraj, Plano, TX (US);
Baher S. Haroun, Allen, TX (US);
Gaurav Chandra, Richardson, TX (US);
Vijaya Bhaskar Rentala, Plano, TX (US);
Venkatesh Srinivasan, Dallas, TX (US);
Hisashi Shichijo, Plano, TX (US);
Krishnaswamy Nagaraj, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
In an apparatus and method for monitoring defects in wafers, a monitoring circuit is fabricated on an area of each one of the wafers. The monitoring circuit includes representative devices that replicate similar devices located in a die area of the wafers. Defects if present in the representative devices contribute to a generation of a noise, thereby causing an imbalance in a differential signal measurable across selected ones of the representative devices. A digitizing circuit that uses a common mode voltage as a reference to measure the imbalance digitizes the differential signal to a digital signal, the digital signal being indicative of the noise generated by the defects. The digital signal is stored over a configurable time interval to form a digital bit stream. The digital bit stream is compared to a reference to determine whether the defects are within an allowable range.