Development of thermal compression bonding with Non Conductive Paste for 3DIC fine pitch copper pillar bump interconnections

High density interconnection is a key technology to realize the miniaturization trend in Integrated Circuit (IC) industry, and to reduce power consumption for next generation mobile devices. In advanced three-dimensional (3D) package, fine pitch pillar bump is deployed not only to fulfill ever-growing I/O density requirement, but also provides better electrical performance than that of traditionally solder bump [1]. Meanwhile, to maximize die area utilization, die sizes of top and bottom die are generally kept as close as possible, leaving stringent spacing for underfilling, and makes fillet width control and dispense space two great challenges for capillary underfill (CUF). In this paper, test vehicle of fine pitch micro-bump interconnection was achieved by thermal compression bonding (TCB) with Non-Conductive Paste (NCP). This paper addresses development of TCB process with NCP material by different TCB condition and NCP properties to show the correlation between TCB process parameter and NCP material. In order to achieve spherical bump shape, NCP gel time was studied in different bump melting time. Fillet width was studied to control the exceeding area around chip. Void was also studied for TCB parameter adjusting. Finally, reliability test was tested for NCP properties discussion.