Flip chips and acoustic micro imaging: An overview of past applications, present status, and roadmap for the future

Acoustic Micro Imaging has been used over the past years to successfully evaluate the quality of flip chip underfill and interconnect bonds. Flip chip technology is steadily progressing toward smaller devices and higher IO count which leads to smaller bumps and bonds. In many instances the small bumps are in close proximity to the edge of a relatively thick silicon chip which leads to information being obscured by edge effects. This is driving AMI technology to provide higher resolution images with improved clarity of information at the edges in order to evaluate the devices. This paper will present an overview of AMI flip chip applications from the inception to the present and include a roadmap for future AMI developments to meet the challenges presented by changes in the design and manufacturing of flip chips.