Ni-Cu低温TLP扩散连接接头组织及性能

Microstructures and properties of joints formed by Ni-Cu TLP bonding process at low temperature

采用厚度40μm的纯锡钎料中间层在镍和铜基板间实现了低温瞬态液相扩散连接(transient liquid phase bonding,TLP Bonding),通过延长等温反应时间,获得了完全由(Cu,Ni)6Sn5和Cu3Sn两种金属间化合物相(intermetallic compounds,IMCs)组成的焊接接头.在Ni-Cu TLP扩散连接液-固反应过程中,Sn/Ni和Sn/Cu界面处均形成了(Cu,Ni)6Sn5,但晶粒形貌存在差异,从镍侧到铜侧化合物形貌依次是小颗粒状、针状和扇贝状.此外,Cu3Sn的生长受到了抑制.该IMCs接头具有418.4℃的重熔温度和49.8 MPa的平均抗剪强度,能够满足高温功率器件封装中对耐高温互连的需求,并且有助于提高电子器件在恶劣条件下服役时的可靠性.

In this study,pure Sn foil with a thickness of 40 μm was used as a solder interlayer in the low-temperature transient liquid phase( TLP) bonding process between Ni and Cu substrates,and joints completely composed of( Cu,Ni)_6Sn_5 and Cu_3Sn intermetallic compounds( IMCs) phases were achieved by prolonging the isothermal reaction time. During the soldering process,the interfacial( Cu,Ni)_6Sn_5 formed on the Ni side and Cu side. However,the grain morphology of the( Cu,Ni)_6Sn_5 compounds subsequently exhibited fine rounded,needlelike and coarse rounded shapes from the Ni side to the Cu side. On the other hand,the growth of the Cu_3Sn compounds was suppressed. The IMCs joint had a remelting temperature of 418. 4℃ and an average shear strength of 49. 8 MPa,which can fulfill the requirement for thermal stable joints in high-temperature power electronics packaging and promote the reliabilities of devices operated in harsh environment.