Highly thermostable joint of a Cu/Ni–P plating/Sn–0.7Cu solder added with Cu balls
- 359 Downloads
Solder joint reliability in power modules is one of the most important issues for hybrid, electric, and fuel cell vehicles; these modules must have highly reliable solder joints, i.e., they must be highly thermostable at temperatures over 175 °C in the future. The soldering surfaces in power modules are often finished with electroless Ni–P plating. Thus, for Cu/Ni–P plating/Sn–0.7Cu joints, it is necessary to suppress Ni diffusion into the solder. Ni diffusion can be suppressed in the presence of a continuous Cu6Sn5 intermetallic compound (IMC) layer at a Ni–P plating/solder interface. To form this IMC, we investigated the composite Sn–0.7Cu solder added with Cu balls. It was confirmed that the addition of 2.5 wt% Cu balls formed a continuous (Cu, Ni)6Sn5 IMC layer between the solder and the Ni–P plating. It is concluded that the IMC layer works well as a Ni diffusion barrier in multiple reflow tests, of which the peak temperature was 330 °C, and in a high-temperature storage test at 200 °C for 1000 h.
KeywordsInductively Couple Plasma Mass Spectrometry Solder Joint Power Module Molten Solder Fuel Cell Vehicle
The authors would like to thank the students in Chukyo University and colleagues in Toyota Motor Corporation for their helpful discussions.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interests.
- 1.Matsubara T, Yaguchi H, Takaoka T, et al (2009) Development of new hybrid system for compact class vehicle. In: Proceedings of JSAE 2009, Japan, p 21Google Scholar
- 3.Nozawa N, Maekawa T, Yagi E, et al (2010) Development of power control unit for compact class vehicle. In: Proceedings of the 22nd ISPSD 2010, Japan, p 43Google Scholar
- 4.Tsuruta K (2011) Prospects of the practical use of SiC power semiconductor devices in automotive applications. Denso Tech Rev 16:90Google Scholar
- 5.Hirose S (2014) Power electronics technology for the next generation environmentally-friendly vehicles. In: Proceedings of the 24th microelectronics symposium, JIEP, Japan, p 37 (Japanese) Google Scholar
- 6.Hirano N, Mamitsu K, Okumura T (2011) Structural development of double-sided cooling power modules. Denso Tech Rev 16:30Google Scholar
- 7.Miura S, Ookura Y, Okabe Y et al (2011) Development of power devices for power cards. Denso Tech Rev 16:38Google Scholar
- 8.Sakamoto Y (2011) Assembly technologies of double-sided cooling power modules. Denso Tech Rev 16:46Google Scholar
- 9.Kadoguchi T, Okumura T, Miyoshi T (2014) Semiconductor module. U.S.Patent, 8,742,556Google Scholar
- 10.Kadoguchi T, Iwasaki S, Kawashima T, et al (2014) Semiconductor device and manufacturing method thereof. U.S.Patent, 8,884,411Google Scholar
- 12.Baldwin C, Such TE (1968) Plating rates and physical properties of electroless nickel/phosphorus alloy deposits. Trans Inst Metal Finish 46:73Google Scholar
- 13.Parker K (1981) Effects of heat treatment on the properties of electroless nickel deposits. Plat Surf Finish 68(12):71Google Scholar
- 14.Kadoguchi T, Yamanaka K, Nagao S, et al (2015) Solder electromigration behavior in Cu/electroless Ni–P plating/Sn–Cu based joint system at low current densities. In: Proceeding of the 48th IMAPS, Orlando, p 141Google Scholar
- 16.Ikeda O, Serizawa K (2009) Joint reliability of high heatproof bonding by Sn–Cu solder. In: Proceedings of the 15th Symposium on microjoining and assembly technology in electronics, Japan, p 59 (Japanese)Google Scholar
- 18.Bader WG (1969) Dissolution of Au, Ag, Pd, Pt, Cu, and Ni in a molten-tin-lead solder. Weld J Res Suppl 48(12):551Google Scholar
- 19.Frear DR et al (1994) The mechanics of solder alloy interconnects. Van Nostrand Reinhold Publishing, New YorkGoogle Scholar