Linear Fracture Mechanics Analysis of Interfacial Delamination in LSI Packages under Temperature Cyclic Loading : 2nd Report, The Effects of Material Properties and Package Geometry Factors

Further fracture mechanics analyses to understand comprehensively the effects of material properties and package geometries on two configurations of delaminations along the interfaces at a) die-bonding layer and b) the bottom surface of the die pad in LSI plastic packages subjected to temperature cyclic loading were performed. Specifically, the effects on these delaminations of such package constituent material properties as 1) coefficients of thermal expansion and 2) Young's moduli of the encapsulant resin and die-bonding material were examined. Package geometry factors such as thickness and width, including chip size were also considered. The analyses were conducted on the basis of three models of delaminated packages, in which large stress intensity factors at the tips of growing delaminations were induced in our previous work. The impact of these parameters on the delaminations were determined and several design guides of Cu alloy and Fe-42% Ni alloy leadframe packages were pointed out