Novel leveling materials for copper deposition in advanced packaging

Abstract

Electroplated copper is rapidly becoming the core technology in wafer level packaging. Although copper pillar technology is not new to the semiconductor industry, it is not without significant challenges. One of the most challenges is to obtain desired co-planarity and bump shape under high throughput and various design. Meanwhile, material properties began to gain people's attention. This paper addresses the challenges with a novel class of copper plating leveling composition, L118 system, which has shown remarkable electrochemical modulation abilities on different patterns. XRD (X-ray diffraction spectra) and FIB (focused ion beam) are utilized to investigate the microstructure of the copper pillars, which exhibits that deposited copper with the novel additives is preferentially (111) textured.