Folks,

Especially with JK's help during my GaAs FA adventure, a few weeks ago, I
was able to determine many interesting factors concerning the use of
MIL-STD-883E's test method 2030. It provides details about using C-SAM
(scanning acoustic microscopy), to visually determine voiding, and gives
graphic acceptance criteria, in percent voiding in, primairly, eutectic and
adhesive bonding of semiconductor devices to whatever substrate required.

This method, and its criteria, is derived, I presume, from data correlating
voiding percentages to thermal conductivity efficiency and effectiveness.
However, it does present some drawbacks.

As I am preparing to use the same method, or something better if available,
do study the effects of various thermal adhesives used to mount RF
amplifiers, and various other device types, to a cold wall. The experiments
must show the relationship of such voiding in selected adhesives to thermal
conductivity. The experiments are straighforward enough. However, the
problem is: it is really hard some times, using C-SAM, as an example, to
really "see" and quantify the voiding percentage amounts. I need assistance
in using a better test method (didn't do well with x-ray on previous
occassions), if available, to better "see" and correlate findings.

All help appreciated.

Earl Moon


Also, I meant to say smooth side facing in toward preg on the issue of
capacitance planes.

Thanks

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