Improved manufacturability of Cu bond pads and implementation of seal design in 3D integrated circuits and packages

Abstract

In this paper we investigated the effect of Cu bonding quality on inter-level via structural reliability for 3D manufacturing applications. We developed a Cu bond pad structure and fabrication process for improved bonding quality by recessing oxides using a combination of SiO2 CMP process and dilute HF wet etching. In addition, in order to achieve improved wafer-level bonding, we introduced a seal design concept that prevents corrosion and provides extra mechanical support. Demonstrations of these concepts and processes prove the feasibility of reliable and manufacturable 3D integrated circuits and packages.