Determination of adhesion and delamination prediction for semiconductor packages by using Grey Scale Correlation and Cohesive Zone Modelling

摘要

Adhesion of moulding compounds on different surfaces like silicon, copper or silver is the most important parameter to optimise with regards delamination behaviour of a semiconductor package. Standard material characterisation methods like Thermo-Mechanical Analysis (TMA) or Dynamic Mechanical Analysis (DMA) do not fully cover this essential parameter.This paper presents results from moulding compound adhesion measurements obtained by using the Button-Shear-Test (BST). The interface cracking of a specimen was analysed by Deformation-Measure-ment-by-means-of-Correlation (DAC) technique which is based on Grey Scale Correlation.Using knowledge of the crack opening derived from DAC, a methodology to determine fracture energies which are necessary to remove the button from the dedicated surface is shown. Based on these energies the possibility of delamination prediction of semiconductor packages by using the Cohesive Zone Modelling (CZM) is described. This simulation approach is demonstrated for a TO220 package and compared with temperature cycle test results.The aspect of material pre-selection by evaluating adhesion in reliability stress tests like High Temperature Storage (HTS) is also discussed.