Characterization Of Coefficient Of Thermal Expansion And Coefficient Of Diluent Expansion Using a Bimaterial Technique

摘要

Thin film devices are used widely in microelectronic areas. Because of CTE (coefficient of thermal expansion) mismatch residual stresses can be built up in a multi-layer system, and the preexisting residual stresses could reduce the service life of such devices through debonding under some environments, such as thermal cycling. In other applications, devices are immersed in diluents and the diluent-induced expansion of polymer coating will also play an important role in the performance of such devices. A bimaterial technique has been extended in order to evaluate the CTE and CDE of the polymeric material in bimaterial system. Because of the CTE or CDE mismatch, a bimaterial specimen shows a curvature due to the expansion or shrinkage of polymer. The bimaterial strip's curvature under thermal excursion was measured to evaluate the CTE of the polymeric material in the bimaterial system. The relation between the curvature of a bimaterial system submerged in a diluent with time was measured to characterize the material's CDE.