Cu/In-Sn-20Cu/Cu复合颗粒TLP焊点的组织形貌及剪切性能研究

Microstructure and Shear Property of Cu/In-Sn-20Cu/Cu Composite Particles TLP Solder Joints

在缩短键合时间的前提下,为降低孔洞生成率,提高焊点力学强度,基于铟-锡-铜复合粉末的瞬态液相连接(TLP),制备了Cu/In-Sn-20Cu/Cu焊点,并研究了键合时间对该焊点显微组织形貌和力学性能的影响。结果表明:焊点组织由界面扩散反应区和钎料原位反应区两部分组成。界面扩散反应区生成的主相为Cu3(In,Sn),并且随着键合时间增加,界面扩散技应区逐渐增厚;随着键合时间的增加,原位反应区先生成Cu6(In,Sn)5,再与Cu原子进一步反应转化成Cu3(In,Sn)。焊点剪切性能随着键合时间的增加呈现先增加后下降的趋势。当键合时间为15 min时,由于致密IMCs与Cu原子的熔合组织,抗剪切强度最高,达到26.54 MPa。当键合时间延长至30 min时,焊点朝着全IMC的方向发展,致使焊点脆性增加,强度降低。

In order to reduce the void formation rate and improve the mechanical properties of the solder joints under the premise of shortening the bonding time, the Cu/In-Sn-20 Cu/Cu solder joints were fabricated by the indium-tin-copper composite powder transient liquid phase(TLP) bonding. The effect of bonding time on the microstructure and mechanical properties of solder joints was systematically investigated. The results show that the joint structure consists of two parts: the interfacial diffusion reaction zone and the brazing material in situ reaction zone. The main phase formed in the interfacial diffusion reaction zone is Cu3(In,Sn), and the thickness of the interfacial diffusion reaction zone increases continuously with bonding time increasing. With the increase of bonding time, Cu6(In,Sn)5 is formed in the in situ reaction zone, and then further reacted with Cu atom to form Cu3(In,Sn). The shear strength of the solder joint tends to increase first and then decrease with bonding time increasing. When the bonding time is 15 min, due to the microstructure of the dense IMCs and Cu atoms, the shear strength is the highest, which is 26.54 MPa. When the bonding time extends to 30 min, the microstructure of solder joint develops toward the full IMCs, resulting in increased brittleness and reduced strength.