Hi Ivan,
It is not all that simple--the CTE of Cu 17-18 ppm/C and the CTE of
glass-reinforced FR-4 18+/-2 ppm/C are not that different. What is different is the way
they change when heated and cooled. Cu changes very little, but the FR-4
resin goes through the glass transition temperature, where it goes from 'glassy'
to 'rubbery' behavior and changes ALL of its properties.



Werner

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