Effect of Ar and N2 plasma etching on adhesion between mold resin and sputtered Cu in semiconductor electromagnetic shielding

Abstract

In recent years, there has been growing demand for processes to form electromagnetic shielding films on the periphery of semiconductor packages, and shielding films are increasingly being formed by sputter deposition methods with stable processes. However, little consideration has been given to the adhesion mechanism between the mold resin and sputtered Cu film formed on the semiconductor devices. In this study, Cu films were sputtered on mold resin with different etching conditions, and X-ray photoelectron spectroscopy was used to analyze the state of the interface, which affects adhesion. The color difference of the mold resin surface under different Ar and N2 etching conditions was also evaluated. Excellent adhesion between the mold resin and sputtered Cu was achieved under a high flow rate for Ar + N2 etching. The amount of Si (SiO2) exposed on the mold resin surface was correlated with the color difference. We proposed a mechanism in which amino groups in particular were formed on the surface of the mold resin, the resin etching rate increased, and the amount of SiO2 exposed increased. Functional groups, especially amino groups, were also formed on the SiO2 surface by N2 plasma. Cuσ+ in the sputtered film and Nσ- formed on the SiO2 surface adhered to each other through polar interactions.