Flip Chips and Acoustic Micro Imaging: An Overview of Past Applications

Flip Chip bonding is widely being used in the microelectronic industry as the method for interconnection. Various methods of flip chip bonding and underfill are presently in use. Acoustic micro imaging has been used since early in the development of flip chips to evaluate the quality of the bump bonds as well as the quality of the underfill. The focus of AMI up to now was to accommodate various thickness of the silicon chips with varying back surface roughness of the chips and still maintain sufficient resolution in the acoustic images to see the interconnects and small features in the underfill. In some cases the imaging technique has to accommodate the flip chip substrates in order to detect the bonds. Currently the aim is to provide transducers and/or imaging methods that ar