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Some lots had very peculiar
rainbow effects on them that could not be removed. The surface
concentration after boron diffusion was substantially out of control on
some slices and fine for others. In the end, we discovered that even a
small touch with tweezers to the platinum boxes resulted in tiny pinholes
in the platinum. There was no way to load the carriers and then place them
in the boxes without using tweezers. After at least of week, maybe longer,
of trying to teach operators not to allow their tweezers to touch the
boxes, we gave up and went back to our old, messy BBr3. One of our planners
was given the chore to collect all of the platinum boxes and to arrange for
metal reclaim so that TI could recover some of its investment. I learned
that good ideas and good test results in a pilot line do not necessarily
equate to success in production. A very useful thing to know and remember.
Even though the IC days of the
60s were essentially pioneer days for IC fabrication and design, the basics
are still used today. Certainly the facilities, the equipment, the sources,
the chemicals, the materials, and the analytical equipment are much more
sophisticated.
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