Process accessibility of high temperature cure type NCP flip chip package

초록

The flip chip technology is a chip and substrate-to-face form of bonding with excellent electrical characteristics by the shorter interconnection distance [1]. As the miniaturization and high-density packaging is needed in the next generation mobile devices, the fine pitch of interconnection is required. NCP(non-conductive paste) is a candidate bonding material replacing capillary underfill in flip chip package process due to its cost effect and free of bridging problem. In this study, NCP formulation and process variables for high temperature flip chip bonding were investigated to form the stable adhesive joint with metallic bonding between bumps. NCPs were formulated with epoxy resin, hardener and catalyst according to the response surface method. Curing behaviors of formulations were measured by DSC(differential scanning calorimetry) techniques. The shear strength and void formation at the joint were measured and the various reliability tests, such as dynamic bending , thermal shock (TS) and highly accelerated stress test (HAST) were conducted.