Kla Corporation

Tzi-Cheng Lai

Stephen Biellak

Jehn-Huar Chern

Jehn-Huar Chem

First and second images of a semiconductor die or portion thereof are generated. Generating each image includes performing a respective instance of time-domain integration (TDI) along a plurality of pixel columns in an imaging sensor, while illuminating the imaging sensor with light scattered from the semiconductor die or portion thereof. The plurality of pixel columns comprises pairs of pixel columns in which the pixel columns are separated by respective channel stops. While performing a first instance of TDI to generate the first image, a first bias is applied to electrically conductive contacts of the channel stops. While performing a second instance of TDI to generate the second image, a second bias is applied to the electrically conductive contacts of the channel stops. Defects in the semiconductor die or portion thereof are identified using the first and second images.

Multi-pass imaging using image sensors with variably biased channel-stop contacts for identifying defects in a semiconductor die

A back-illuminated image sensor includes a first pixel, a second pixel, and a channel stop situated between the first pixel and the second pixel to isolate the first pixel from the second pixel. The channel stop includes a LOCOS structure and a region of doped silicon beneath the LOCOS structure. The back-illuminated image sensor also includes a first electrically conductive contact that extends through the LOCOS structure and forms an ohmic contact with the region of doped silicon. The first electrically conductive contact may be grounded, negatively biased, or positively biased, depending on the application.

Image sensors with grounded or otherwise biased channel-stop contacts

An image sensor is provided that includes a pixel array divided into a plurality of pixel groups. Each pixel group is clocked by a respective plurality of horizontal-register clocks. Clock signals for the image sensor are adjusted. Adjusting the clock signals includes phase-shifting each plurality of horizontal-register clocks by a respective phase delay of a plurality of phase delays. The phase delays are evenly spaced and are spaced symmetrically about zero. With the clock signals adjusted, a target is imaged using the image sensor.

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San Jose, CA, United States of America

Tzi-Cheng Lai