In-Sn Passivated Low Temperature and Low Pressure Cu-Cu Interconnects
Part Of
2026 International Conference on Electronics Packaging and Hybrid Bonding Symposium, ICEP-HBS 2026
Start Page
144
End Page
145
ISBN (of the container)
9784991483516
ISBN
9784991483516
Date Issued
2026
Author(s)
Abstract
Recently, Cu-Cu bonding has emerged as a key solution for high-density interconnections in heterogeneous integration. Among various Cu-Cu bonding approaches, solid-liquid interdiffusion (SLID) is one of the critical technologies. This study introduces a novel In-Sn passivation approach, which is built upon the Cu-Sn binary SLID system, to further reduce bonding temperature and pressure requirements. The passivation layer was fabricated by electroplating, and a diffusion barrier layer was incorporated to prevent the premature growth of intermetallic compounds (IMC) between the Cu and In. Thermal compression bonding was performed under atmospheric conditions, where the melting In-Sn compensates for the non-uniformity and surface roughness of the Cu pillars. Consequently, this work proposes a novel low temperature and low pressure fine-pitch Cu-Cu bonding approach, utilizing a fully wet-chemical, CMP-free process conducted in an atmospheric condition. Various characterization, including cross-sectional Focused Ion Beam (FIB), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDS), were employed to evaluate the interfacial reactions prior to bonding and the resulting joint properties.
Event(s)
25th International Conference on Electronics Packaging, held in conjunction with the IEEE EPS Hybrid Bonding Symposium, ICEP-HBS2026, 14 April 2026 - 18 April 2026, Hiroshima
Subjects
CMP-free bonding
Cu-Cu bonding
In-Sn passivation
SLID
Publisher
Institute of Electrical and Electronics Engineers Inc.
Type
conference paper