Regulating the valence state of lead ions in lead aluminosilicate glass to improve the passivation performance for advanced chip packaging

Abstract

Eliminating surface ion contamination, increasing the reverse breakdown voltage and reducing the leakage current are extremely important for semiconductor devices. Herein, we demonstrated that regulating the valence state of lead ions in lead aluminosilicate glass can efficiently improve the performance of glass passivation technique for chip packaging. It was found that heat treatment technique can be utilized to control valence state of lead ions from +4 into +2 in 20PbO-4.8Al2O3-75.2SiO2 (mol%) (PAS) glass powder, which induces transformation of [PbO3] units into stable glass former units of [PbO4] and generates a free state and charge compensator of Pb2+, therefore contributing to a more stable structure and discoloration of glass. As a result, the optical band gap of glass powder was enhanced from 4.1772 to 4.3184, which could significantly improve glass insulation. As a demonstration of chip packaging, PAS glass powder, after heat treatment processing into a paste for the passivation layer of metal–oxide–semiconductor (MOS) structure devices shows a tight and integrated structure and exhibits a lower fixed charge density from 3.97 × 1010cm−2 to 2.73 × 1010 cm−2. This work provides techniques to adjust the structure of glass to enhance the passivation performance of glass for chip packaging.