Jeffery,

I certainly apreciate your posting as a reminder to me as well. I would add,
from a DFM point of view concerning materials and their processing:

Getek has good electrical properties, as you say, but processing and some
results associated with it can be dissapointing. This material must be
processed more along the lines of polyimide. It requires a more damanding
press cycle than those for FR4 types using simple straight up processing
from 0 to 90 minutes or so. Therefore, not all shops like or do well with it.

The Rogers and Arlon (liscensed from Rogers but with slight variations
concerning properties) material is really neat stuff. It has processing
drawbacks as well as being limited in prepreg glass styles and thicknesses
when reinforced. If improperly processed, as with any material type, it has
several failing characteristics. As is widely known, this type material
often is married/laminated to Getek to meet design and performance
requirements. Really low DC and loss tangents.

My money is on BT epoxy blends when and where possible. It has high
performance characteristics and is easily processed. I have designed it in
and used in in very complex, large, high layer count MLB's with great
success. It is/was used in some Cray designs built by IBM, as one example.

Just wanted to add to your good comments,

MoonMan

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