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| From [log in to unmask] Wed Feb 5 08: |
47:50 1997 |
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Hi TechNetters!
We use a multilayer pcb made from basically FR4 with a Tg of 135°C.
There are pths, blind microvias, buried vias and some fine line wiring
(only on top and bottom). One of our processing steps in building up the
assembly (after smd-soldering both sides and cleaning) is die attach
with an adhesive. The recommended curing cycle of the adhesive is 1 h
(actual it may be 2h ore more) at 150°C and is done in a convection oven
under normal atmosphere.
I am interested in the cons of above curing temperature and time. Are
there any reliability issues concerning the pcb? To my knowledge,
laminating the pcb's by the manufacturer is done at even higher
temperatures (although under vacuum).
Any comments are welcome.
Ulrich Korndörfer
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