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You might think that some of the early glass
deposition systems looked like grandma’s high-pressure steam cooker.
You wouldn’t be far from wrong, because that’s exactly what they got
their start in.
This model still retains that look, even though it survived well
into the nineteen eighties. Original non-epitaxial ‘glass’ CVD films
emerged in high temperature diffusion furnaces. Then it was
recognized that by predoping and using pressure control the
temperatures could be lowered to the range of 300-450 ºC. This
beauty could operate at 40-100PSI in temperatures from 380-450 ºC.
Tempress was one of those early evergreen companies providing a wide
range of equipment into the industry. It was acquired by General
Signal in the late seventies in a move to become a general store for
semiconductor manufacturing equipment.
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