Investigation of ethylene glycol, α-terpineol, and polyethylene glycol 400 on the sintering properties of Cu–Ag core–shell micro/nano-mixed paste

With the rapid development of the 3rd semiconductors, the metal nanoparticles are investigated to be applied in the die-attached interconnect materials. However, the organic solvent used in the nanoparticle paste needs to be addressed. In this work, we adopted the liquid phase reduction method to synthesize Cu–Ag core–shell micro/nano-mixed particles (Cu@Ag MNPs), which achieved better anti-oxidation properties than Cu MNPs. Due to the suitable boiling point and viscosity, the electrical properties and hardness of the sintered films prepared by polyethylene glycol 400 (PEG-400) are better than those of ethylene glycol and α-terpineol. The electrical properties reach 43.82 µΩ cm and the hardness reach 61.3 HV at 300 °C. The shear strength of the joint sintered by Cu@Ag MNPs paste with PEG-400 can reach 20.14 MPa at 300 °C. Besides, the sintered Cu@Ag MNPs film exhibits a denser structure than Ag MNPs and Cu MNPs film. Therefore, Cu@Ag MNPs have great development prospects in the 3rd semiconductors.