Simulation and Experiment of Liquid-Phase Microjoining Using Cone-Shaped Compliant Bump

摘要

In order to meet the requirements of high-density interconnection in 3D-LSI, we have proposed easy-deforming compliant bumps (10 μm-diameter / 20 μm-pitch) to lower the pressing load during bonding. But still, when the number of I/O connections approaches to or larger than 1,000,000, the pressing load becomes too heavier to be carried out by an available flip-chip bonder. The load problems of compliant bumps can be overcome by liquid phase bonding method. On the other hand, the shrinkage of bump pitch is restricted by the spread of melting solder as far as the existing bump technology is used. In this paper, this constraint can be overcome by using the cone-shaped compliant bump as a counter electrode of solder bump. We show experimental results together with simulation of fluid dynamics of molten solder.