Non-Conductive Adhesive (NCA) Trapping Study in Chip on Glass Joints Fabricated Using Sn Bumps and NCA

Abstract

Chip-on-glass (COG) bonding using a nonconductive adhesive (NCA) and the entrapment of NCA and fillers in the COG joints were studied. Sn was used as a bump material because it has a higher propensity of plastic deformation than an Au bump. Three types of Sn bumps were fabricated, electroplated Sn bumps, reflowed Sn bumps, and coined Sn bumps. Three types of NCAs were applied during COG bonding. The reflowed bump had the least amount of trapped NCA with fillers among the bumps studied. The NCA with the lowest viscosity was trapped the least compared to the other NCAs. The electrical test results showed that contact resistance increased with increasing amounts of trapped NCA with fillers in the COG joint.