High-quality multiple global layers on chip-redistributed wafer for wafer-level system integration using pseudo-SOC

Abstract

This paper reports an advanced process to realize high-quality multiple global layers on high-accuracy chip-redistributed wafer for wafer-level system integration using pseudo-SOC. We have been developing pseudo-SOC (p-SOC) technology by which KGD chips are integrated to a chip-redistributed wafer using high-rigidity epoxy resin and global layers with interconnecting chips are formed on it. The basic process has been established for p-SOC, and integration of MEMS and LSI, or front-end RF LSI and passive components, has been demonstrated. However, the first stage of p-SOC technology was based on a single global layer consisting of an insulating layer and a conductive layer, which limited the range of application. It is desirable to realize high-quality multiple global layers on the high-accuracy chip-redistributed wafer in order to expand its application toward system-level integration. For this purpose, it is necessary to keep all processes at low temperature for the reduction of warpage in the resin-based chip-redistributed wafer during several resin curing processes, to readjust resin-based materials, and to obtain high accuracy of chip position in chip-redistributed wafer. We developed the advanced p-SOC process to resolve these technical issues by improving the hardening process of resin, employing low-temperature-curing polyimide and optimizing the stress analysis by FEM simulation. As a result, realization of a novel one-chip module for a versatile high-sensitivity amplifier is demonstrated.