A Study of Defects in High Reliability Die Sort Applications

For high-reliability microelectronics with uses in aerospace, defense, automotive, and medical applications, in-line visual inspection during the die sort process allows for a higher quality and more robust process for generating known-good-die. The visual inspection serves three primary functions: verifying unique device characteristics (such as bumps, MEMS structures, waveguides, etc.), verifying the device is free from singulation defects, and verifying the die sort process induces no device damage. Performing a visual inspection of the die top surface and one edge during the pick and place process allowed qualification of a non-surface contact edge grip approach for sensitive surface MEMS and optoelectronic parts. Die 100 microns thick or less were also inspected to ensure no cracking during the die pick process. For continual process reliability improvement and optimization, the inspection results must be captured and logged along with incoming product details including the wafer ID, electrical test results, and chip ID. This logged information is then traceable to the die position in the output medium. As new device manufacturing technology is implemented, this screening for process-induced defects is required for a robust manufacturing process.