Andrew Chang
Sponsored
By: UC-SMART #97-01
Abstract
Currently, an investigation on acoustic emission (AE) sensing strategies for chemical-mechanical
polishing (CMP) monitoring is underway. A unique signal processing technique that involves a
time-averaged comparison of high to low frequency events, AE ratioing, is being evaluated. With a
sensor coupled to the backside of the wafer, preliminary results show that AE ratios can differentiate
polishing between oxide and bare silicon wafers. A sensitivity investigation will be performed to
compare different CMP operating conditions such as metal polishing, IC pattern dependency, and the
effects of different CMP consumable sets. This new methodology shows potential for implementation
in an endpoint detection (EPD) system.
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