Endoscopic inspection of solder joint integrity in chip scalepackages

摘要

This paper reports the use of endoscopy for the nondestructiveexamination of solder joint integrity in chip scale packages (CSP) suchas flip chip on flex. Borrowed from the medical instrument technology,the endoscope is used to examine visually the inside of an organ. Thisconcept has now been developed and refined by ERSA and KURTZ, and led toan ERSASCOPE inspection system coupled with sophisticated butuser-friendly software for data and image analysis. We have successfullyused this endoscopic method to evaluate the solder joint integrity inCSP such as cold joints, standoff height measurements, and probing ofinner rows of ball joint integrity. Since this new instrument has onlybeen introduced very recently, we will also report the latest resultsfor obtaining the optimal examination of solder joint integrityachievable. By analyzing many varieties of CSP samples, we havewitnessed the tremendous power of endoscopy when applied to thenondestructive examination of CSP solder joints, and found this methodof immense use to the quality assessment of miniaturized electronicpackages. We also give a critical review of this inspection method whenapplied to CSP