Appeal No. 1997-4043 Page 3
Application No. 08/124,332
BACKGROUND
The invention at issue in this appeal comprises a method
of, and a cover plate used in, ultrasonic testing (UT).
Immersion UT is a known technique for detecting internal flaws
in machined parts or materials. A piece to be tested is
immersed in a fluid, and an ultrasonic transducer sends
ultrasonic waves through the fluid and into the part. The
ultrasonic fluid enhances the coupling of ultrasonic waves to
the piece. Voids, inclusions, cracks, or other defects in the
piece reflect the ultrasonic waves passing through the
component. The reflected ultrasonic waves are analyzed to
detect such defects.
Immersion UT cannot be used to test materials that might
react with an immersion fluid, thereby damaging the material.
Specifically, targets used for semiconductor manufacturing
often include a sputtering surface of a porous material such
as tungsten, titanium, iron, terbium, cobalt or copper, which
are likely to be damaged by immersion and thus rendered
worthless.
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