Enhanced shear strength and microstructure of Cu–Cu interconnection by low-temperature sintering of Cu nanoparticles

Sintering of Cu nanoparticles at low temperature is a promising material for advanced power electronic packaging; while its sintering quality is significantly inhibited by oxides. In this work, the Pt-catalyzed formic acid and decomposition of mixtures of organic compounds and copper formate were utilized to eliminate Cu nanoparticles from oxidation to promote Cu atomic diffusion and form strong bonding. The results indicated that the sintered neck length was longer in the Pt-catalyzed formic acid environment, and the stronger atomic diffusion and interparticle bonding was formed. The shear strength of the sintered Cu–Cu joint reached 49 MPa at 180 °C. Furthermore, the effects of temperature and pressure on the formation and growth of sintered necks, pore eliminations, densification, and bonding strength were discussed. This work could provide industrial insights from realizing low-temperature sintering used in the field of power electronics.