Surface Protecting and Particles Removing after Wafer Sawing for Die-to-wafer Hybrid Bonding

Hybrid bonding technology has become an essential approach to fulfill the Chiplets technology. The wafer dicing process before die-to-wafer (D2W) hybrid bonding will introduce a large number of particles on the die surface. The method of surface protection and particles removal is urgently needed for D2W hybrid bonding with the bonding pitch scaling down. In this study, the photoresist mask and polydimethylsiloxane (PDMS) are innovatively introduced to protect the wafer before dicing and post-clean the particles after dicing. After laser dicing, the average particle density on the surface of chips without any protection is 83.07 mm
^-2
. The mixture mask of AZ4620 photoresist and PDMS film before dicing reduce the average particle density to 19.71 mm
^-2
. Further PDMS adhesion treatment as the post-clean reduces the average particle density to only 7.60 mm
^-2
. It indicates the surface protecting by photoresist and PDMS mask and particles removal by PDMS is qualified to be used in the die sawing and cleaning. Organic residue on the chip surface after PDMS immersion is also detected and O
2
plasma treatment is effective to remove the organic residue. The surface roughness of chips descends after PDMS immersion. The results show that the PDMS is effective for surface protection and particles removal, which is suitable for D2W hybrid bonding.