Rapid in-situ formation of Cu-Sn full intermetallic compound films and their joint strengthening mechanisms

Abstract

Cu-Sn full intermetallic compounds (IMC) have emerged as promising interconnection materials for power semiconductor packaging, owing to their excellent electrical conductivity and thermal stability. However, traditional fabrication methods often require prolonged processing times, which constrain their application in high-efficiency electronic packaging. In this study, an advanced dual-beam laser co-deposition technique combined with real-time heating was developed to rapidly fabricate pure Cu₆Sn₅ films in situ, tailored for power electronic packaging applications. Under conditions of 260 °C and 15  MPa bonding pressure, the Cu-Sn full IMC joint achieved a shear strength of up to 72 MPa within only 3 min. The mechanisms underlying the rapid IMC formation and joint strengthening during the thin-film preparation were systematically explored. Furthermore, SiC diode samples bonded with these thin films were subjected to power cycling tests, showing durability exceeding 40,000 cycles at junction temperatures above 160 °C. These findings highlight the potential of Cu-Sn full IMC joints for next-generation power electronics packaging.