METHOD FOR AUTOMATED NONDESTRUCTIVE ANALYSIS OF FLIP CHIP UNDERFILL

摘要

For many years Acoustic Micro Imaging (AMI) techniques have been utilized to evaluate the quality of the underfill used to support the solder bump interconnections of Flip Chip type devices. AMI has been established as one of the few techniques that can provide reliability and quality control data, but little has been done to automate the evaluation process for Flip Chip underfill until now. An automated analysis method has been developed and tested on a variety of Flip Chip structures that provides more consistent and accurate analysis than manual, visual examination by operators. The automated analysis provides unbiased, repeatable evaluation data for part-to-part and lotto- lot comparisons to ensure that the process is within its control limits, providing a more reliable product. This new method of analysis incorporates techniques that provide data on how well individual solder bumps are being supported by the underfill or an overall percentage void measurement, depending on the level of detail required for the process. The analysis functions also have built-in capabilities to automatically account for process variations. Example acoustic microscope images and automated data analysis results for a set of Flip Chip devices will be presented to help explain the methods utilized to obtain consistent and accurate information for process evaluation.