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Non-destructive Method to Evaluate Polishing Damage on the Surface of a Ceramic Substrate

IP.com Disclosure Number: IPCOM000121229D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Hu, D-C: AUTHOR

Abstract

This article describes a new method employing an optical detection technique for evaluating the quality of an as-polished ceramic surface.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 76% of the total text.

Non-destructive Method to Evaluate Polishing Damage on the Surface
of a Ceramic Substrate

      This article describes a new method employing an optical
detection technique for evaluating the quality of an as-polished
ceramic surface.

      The major constituent of ceramic substrates used in
semiconductor device manufacture and packaging is alumina. Stress
generated to the alumina grains during surface planarization
(polishing) of the substrate can cause electrical defects due to
ceramic pullouts.  If the force is too high, it can either break the
second phase between alumina grains, causing the ceramic to pull out,
or partially break the second phase, causing a discontinuity in the
ceramic substrate.  The disclosed technique takes advantage of the
fact that alumina is translucent in visible light.  When light shines
through an alumina grain where the second phase is partially broken,
the light will be scattered at the discontinuity, thereby allowing
for flaw detection by a photomultiplier or similar device.  The
quality of the polished surface can thus be evaluated in a
non-destructive manner by use of this technique.

      By way of demonstration, when a substrate is evaluated under a
laser scanning microscope, the light generated at the discontinuity
is detected by the photomultiplier attached to the scope.  This is
determined by "bright areas" showing up around the ceramic pull-out
locations.  Partially adhered grain can also be detected by this
meth...