Microstructural and textural analyses of flip chip bonded gold by orientation mapping

Orientation mapping based on electron backscatter diffraction (EBSD) technique is applied to reveal microstructural and textural characteristics of flip chip bonded Au at its different processing stages. Attention is paid also to the influence of thermosonic energy. It is found that columnar grains in free air ball (FAB) that inherit the orientations of heat affected zone (HAZ) and layer formed grains are formed at first bonding interface owing to the thermosonic vibration. Recrystallised grains are occasionally detected between the heavily strained boundary region and the less strained centre region.