Hybrid Bonding With Particle Accommodation Using Polymer Dielectric: Design, Process and Yield Study

Hybrid bonding has become a critical solution to enable fine pitch direct copper-to-copper (Cu-Cu) interconnection. In conventional oxide/Cu hybrid bonding, success is contingent on wafer surface cleanliness. A significant challenge in chip-level bonding arises from silicon debris generated during the mechanical dicing process, which contaminates the wafer surface. This study introduces a low-temperature-curable polymer dielectric designed for hybrid bonding using mechanically diced chips. The polymer provides excellent defect coverage and enhanced particle tolerance. We demonstrate polymer/Cu hybrid bonding on memory chips with dense $10 \mu ~\mathrm{m}$ pitch Cu bumps and known particle contamination. The polymer/Cu hybrid bonding alignment precision of less than $2 \mu ~\mathrm{m}$ is achieved. Additionally, the study explores the process window of polymer CMP and reveals that the bonding yield relation with the copper bump protrusion from the polymer surface.