Measurement of deformation and strain in flip chip on BGA (FC-BGA)

An autofocus digital image correlation (DIC) workstation, incorporating image stacking functionality was used to perform a thermo-mechanical deformation and strain analysis of controlled collapse chip connect (C4) bumps in two FC-BGA packages. Cross-sections through the C4 bumped region were analysed through a temperature cycle from ambient temperature up to 100/spl deg/C. Strain concentrations at the C4 layer-to-die interface are revealed. Aspects of recent advances in digital image correlation technology are described in the context of this study.