volume 34, issue 24, P1815-1822 1994
DOI: 10.1002/pen.760342406
View full text

Abstract: Abstract Coefficient of thermal expansion mismatch between the epoxy layer and composite substrate of “inner layers” can lead to large residual stresses during the manufacture of printed wiring boards (PWB). The viscoelastic nature of the polymeric resin (epoxy) leads to a relaxation of the stresses and a resulting change in dimensions of the inner layer over long periods of time. Here, we treat a micro‐mechanical model using linear viscoelasticity in a finite element thermal stress analysis to demonstrate th…

expand abstract