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 ev aluate the quality of flip chip underfill and interconnect bonds. Flip chip technology is steadily progressing toward smaller devices and higher IO co unt which leads to smaller bumps and bonds. In many instances the small bum ps are in close proximity to the edge of a relatively thick silicon chip wh ich leads to information being obscured by edge effects. This is driving AM I technology to provide higher resolution images with improved clarity of i nformation at the edges in order to evaluate the devices. This paper will p resent an overview of AMI flip chip applications from the inception to the present and include a roadmap for future AMI developments to meet the chall enges presented by changes in the design and manufacturing of flip chips. ( C) 2000 Elsevier Science Ltd. All rights reserved.