Microstructure of Transient Liquid Phase Sintering Joint by Sn-Coated Cu Particles for High Temperature Packaging

Abstract

We develop a transient liquid phase sinter (TLPS) bonding using Sn-coated Cu micro-sized particles. With this bonding process, a thermally stable joint comprising Cu3Sn phase and a dispersion of ductile Cu particles can be obtained. The particle paste, which contained Cu particles with a thin Sn coating and terpineol, was used to join Cu substrates. The setup was bonded at 300 °C for 30s under an applied pressure of 10 MPa using a thermo-compression bonding system under a formic acid gas atmosphere for reducing the oxide layer on the Sn coating and the Cu substrate. After bonding, the TLPS joint showed a thermally stable microstructure with a good shear strength, which was fully consisted of Cu3Sn intermetallic compounds matrix and embedded ductile Cu particles. The kinetics of the microstructure transformation and high temperature reliability of the TLPS joint were investigated. After 300 °C isothermal aging for 200h, the shear strength and microstructure of the TLPS joints showed almost unchanged. The results demonstrate that joint with high-melting-point obtained by the TLPS bonding using Sn-coated Cu particle paste has the potential to fulfill the requirement of high temperature electronic packaging.

Transient Liquid Phase Bonding of Copper Using Sn Coated Cu MWCNT Composite Powders for Power Electronics

“…As the advancement in the electronic era proceeds, power devices are finding their scope in automotive, aerospace, and electronics industries. In recent years, the incorporation of new semiconductor materials like SiC, GaAs, Si 3 N 4 , and AlN in power devices demands stable interconnects with high operating temperatures (>250 • C) [1]. Therefore, the conventional low melting point solders such as Sn-Pb, SnAgCu, and Sn-Bi cannot be used for power electronic devices [2].…”

“…Currently, these power devices are interconnected using thermo-compression joining [3], high temperature soldering [4], and nano Ag paste sintering [5]. However, the major drawbacks in these methods are (1) high joining temperature, which enhances the interface diffusion; (2) high applied pressure, which damages the semiconductor substrates; and (3) high manufacturing cost.…”

Prediction and Mitigation of Vertical Cracking in High-Temperature Transient Liquid Phase Sintered Joints by Thermomechanical Simulation

“…This decouples the process completion time from the joint thickness, because the required IMC thickness is equal to the short distance between high-melting temperature particles. Because of these advantages, considerable research has been pursued on the Cu-Sn [14][15][16][17][18][19][20][21][22] and Ni-Sn [18,[23][24][25][26][27] material systems in the last years.…”