US Patent No. 10,923,526

MULTI-PASS IMAGING USING IMAGE SENSORS WITH VARIABLY BIASED CHANNEL-STOP CONTACTS FOR IDENTIFYING DEFECTS IN A SEMICONDUCTOR DIE


Patent No. 10,923,526
Issue Date February 16, 2021
Title Multi-pass Imaging Using Image Sensors With Variably Biased Channel-stop Contacts For Identifying Defects In A Semiconductor Die
Inventorship Tzi-Cheng Lai, San Jose, CA (US)
Jehn-Huar Chem, Morgan Hill, CA (US)
Stephen Biellak, Sunnyvale, CA (US)
Assignee KLA Corporation, Milpitas, CA (US)

Claim of US Patent No. 10,923,526

1. An imaging method, comprising:generating a first image of a semiconductor die or portion thereof, comprising:
in an imaging sensor, while illuminating the imaging sensor with light scattered from the semiconductor die or portion thereof, performing a first instance of time-domain integration (TDI) along a plurality of pixel columns comprising pairs of pixel columns in which the pixel columns are separated by respective channel stops, wherein the channel stops comprise respective localized oxidation of silicon (LOCOS) structures, respective regions of doped silicon beneath the respective LOCOS structures, and electrically conductive contacts that extend through the LOCOS structures and form ohmic contacts with the regions of doped silicon; and
while performing the first instance of TDI, applying a first bias to the electrically conductive contacts;
generating a second image of the semiconductor die or portion thereof, comprising:
in the imaging sensor, while illuminating the imaging sensor with light scattered from the semiconductor die or portion thereof, performing a second instance of TDI along the plurality of pixel columns; and
while performing the second instance of TDI, applying a second bias to the electrically conductive contacts; and
identifying defects in the semiconductor die or portion thereof using the first and second images.