Development of hybrid bonding using area-selective passivation layer deposition technology on various substrates for heterogeneous integrated structure

Abstract An advanced area-selective deposition approach for passivation layers in Cu/SiO 2 and Cu/PI hybrid bonding structures is introduced in this study to reduce costs and process complexity compared to traditional PVD passivation. This method includes ultra-thin film via plasma pretreatment, successfully depositing passivation layers with precise thickness control which the Cu atoms could successfully diffuse through. The excellent hybrid bonding quality is achieved in the deposition of passivation layers, with successful bonding observed at temperatures ranging from 250 °C to 180 °C. Area-selective deposition on copper pads as small as 3 μ m achieves complete area-selectivity, highlighting its significant potential for fine-pitch hybrid bonding applications. The outstanding electrical characteristics of Cu/SiO 2 and Cu/PI hybrid bonding structures confirm excellent bonding quality in this study.