Plasma Dicing Process-Flows for Advanced Packaging Fabrications

Comprehensive investigations were conducted on identifying integration efforts needed to adapt plasma dicing technology in BEOL pre-production environments. First, the authors identified a few suitable process flows. Within the plasma dicing process flows, laser grooving before plasma etching was shown to be a key unit process to control the resulting die sidewall quality. Significant improvement on laser grooving quality has been demonstrated. Through these efforts, extremely narrow kerfs and near ideal dies strengths were achieved on Si dies. The Bosch-etching based plasma dicing process generates fluorinated polymer residues both on the Si die sidewalls as well as under the topography overhangs on wafer surfaces, such as under the solder balls or micro-bumps. The fluorinated polymers in certain areas cannot be cleaned by an in-chamber post-treatments. Multiple wet chemistry-based cleaning methods demonstrated excellent process capability, and are compatible with plasma singulated dies-on-tape handling. Lastly, many methods exist for backside metal and under Si die-attach-film (DAF) separations. The authors highlighted recent processing results suitable for post-plasma dicing die separations of such film materials.