Particle Removal by Surface Protection and Adhesion in the Wafer Dicing Applied to Chip-to-Wafer Hybrid Bonding

Abstract

Controlling particles in wafer dicing chip-to-wafer (C2W) hybrid bonding has been a vital issue for yield assurance. In this study, laser dicing, blade dicing and plasma dicing are first compared and plasma dicing is considered as the cleanest dicing method. Second, wafer surface protection by photoresist AZ4620 and a PDMS adhesion layer before wafer dicing is investigated. It is found that a thick protective layer mixing photoresist and PDMS together provides better protection effect, reducing particle density from 47.25 mm−2 to 19.71 mm−2. Then, surface protection of SiO2 by surface energy reduction is accomplished by spin-coating AR300-80-new and CF4 plasma treatment. The particle density shows a more significant decrease after CF4 plasma, owing to its greater effectiveness to lower dispersive component ( $\gamma _{\mathrm {sd}}$ ) and the effect of increasing surface roughness. Finally, the particle density is further reduced by PDMS adhesion from 19.71 mm−2 to 7.60 mm−2. PDMS residue on the chip surface is detected by dynamic secondary ion mass spectroscopy (D-SIMS), and removed by O2 plasma treatment. The results provide feasible suggestions and approaches to decrease the deposition and adhesion of the particle generated from wafer dicing in C2W hybrid bonding.