A Study of 3D Packaging Interconnection Performance Affected by Thermal Diffusivity and Pressure Transmission

Abstract

3D packaging technology has been considered as one of the best candidates to improve the system performance by implementing high I/O density as well as providing shortest signal channel path with given package form factor. However, it is difficult to uniformly control the bonding thickness and the precisely align the bumps other than thermo compression (TC) bonding to enable 3D packaging. Moreover, high chip cost and possibly low productivity of TC bonding are main business reasons to prevent this attractive technology from prevailing the mass production environment. To address these well-known technical issues of TC bonding, non-conductive film are proposed for especially high vertical stack with small bump pitch and also minimum chip to chip distance required packages such as high bandwidth memory. In this article, we investigated key process parameters to understand how to optimize bonding process to ensure excellent joint quality for highly dense 3D packages products.