HV-H3TRB Evaluation of Ag and Cu Sintering Paste for Double-Sided Sintered Power Devices

Double-sided sintering can be used to eliminate aluminum wire bonds for even higher levels of power electronics reliability than currently attained by die-attach sintering. Double-sided sintering brings the sintering paste and, thus, very fine metal particles extremely close to the edge termination of the power devices. This could facilitate electrochemical migration, leading to short circuits across the device's edge termination. To investigate this, we manufacture four variations of test vehicles for HV-H3TRB testing. The variants include Si diodes with pure Cu top metal, Cu wire bonds, and top-side sintered bond buffers. The sintering process reveals that the rheology of our Ag paste is better suited for precise printing as is required on the die-top. The Cu paste produces bleed-out as well as squeeze-out during sintering. One device fails HV-H3TRB, which is attributed to the Cu pate squeeze out, as no dendrites can be detected.