Surface Quality Challenges Associated with Temporary Bonding and Debonding Process for Chip Stacking Applications

Temporary bonding and debonding (TBDB) are crucial steps in multi-chip stacking via chip-to-wafer hybrid bonding and enables backside processing and thin wafer handling. However, achieving a high-performing hybrid bonding interface requires stringent surface quality control, including cleanliness and roughness. Despite progress in temporary bonding materials, wafer surface quality after debonding and cleaning wafers mounted on a film-frame involves several practical challenges and remains understudied. In this study, cleaning processes involving mild chemistry (compatible with film-frame mounted wafers), temperature control, and process sequence optimization have been developed to efficiently remove residual bonding material with no dielectric surface roughening. We evaluate various wet cleaning methods, including solvent and ozonated DI water (DIO3)-based solutions, to ensure effective residue removal and improve overall device roughness.