AUTOMATED X-RAY INSPECTION OF CHIP-TO-CHIP INTERCONNECTIONS OF SI-ON-SI MCMS

The silicon-on-silicon (Si-on-Si) multichip module (MCM) is one of the newest system integration technologies that has the potential for hig h functional integration, enhanced performance, and cost effectiveness . Aside from functional tests, X-ray inspection is required to ensure good quality chip-to-chip interconnections during the fabrication proc ess, This paper presents an automated inspection system that is capabl e of detecting defects such as ''swollen'' solders, misaligned solders , missing solders, solder robbing, and solder bridging in a semifinish ed MCM, The semi-finished MCM is in wafer form and has completed the f ollowing operations: stencil printing, device placing, and solder refl owing. The defect detection methodology is detailed, Over a test set o f 54 sample images of wafer tiles, 100% inspection accuracy was obtain ed, This system has the potential to automate the manual visual inspec tion operation which is tedious, slow, and error-prone.