Sintering of Copper Particles for Die Attach

First steps are taken toward a low-cost alternative to silver sintering as a highly reliable die attach technology for deep drilling applications and future power electronic modules. In this feasibility analysis, we evaluate sintering of copper particles for die attach. Particulate copper pastes are pretreated in H₂ atmosphere (50 mbar) in order to gain oxide-free particles. Subsequently, particles are sintered at a pressure of 40 N/mm² and a temperature of 350°C for 2 min. Porosity, Young´s modulus as well as electrical and thermal conductivities of sintered layers are analyzed. Moreover, shear tests at ambient temperature are performed for evaluating the adhesion of monometallic as well as Cu-Au bonds according to the American military standard for chip-substrate contacts (MIL-STD-883H, method 2019.8).