Plasma Dicing Fully Integrated Process-Flows Suitable for BEOL Advanced Packaging Fabrications

Abstract

Comprehensive investigations were conducted on identifying integration efforts needed to adapt plasma dicing technology in BEOL pre-production environments. First, the authors identified the suitable process flows. Within the process flow, laser grooving before plasma dicing was shown to be a key unit process to control 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 bare Si dies. Plasma dicing process generates fluorinated polymer residues on both Si die sidewalls and under the topography overhangs on wafer surfaces, such as under the solder balls or microbumps. Certain areas cannot be cleaned by in-chamber post-treatments. Multiple cleaning methods demonstrated process capability and compatibility to singulated dies-on-tape handling. Lastly, although many methods exist commercially for backmetal and DAF separations, the authors' investigation is still inconclusive on one preferred process for post-plasma dicing die separations.