Development of micron-sized Cu-Ag composite paste for oxidation-free bare Cu bonding in air condition and its deterioration mechanism during aging and power cycling tests

The development of next-generation power electronics requires the semiconductor power devices with higher voltage endurance, higher electrical current density under high -temperature operations above 250 & DEG;C. Herein, we propose the uses of combined micron -sized Cu particles with Ag-amino composite to achieve a robust direct Cu-Cu bonding under a low sintering pressure and temperature (300 & DEG;C) in ambient atmosphere. The strong bonding strength of the Cu-Cu joint structure was evaluated as high as 45.3 MPa under 300 & DEG;C sintering temperature with low pressure (1 MPa). For the high temperature reliability evaluation, the sintered Cu-Ag composite Cu-Cu joints were stored at 250 & DEG;C in air. The shear strength of the joints remains above 30 MPa after 500 h ageing, suggesting an excellent mechanical stability during high temperature storage. Additionally, a SiC Schottky barrier diode with the sintered Cu-Ag composite joint structure was evaluated during a power cycle test at a junction temperature of 200 & DEG;C for 10,000 cycles. The thermal resistance of the joint structure was almost unaffected, and no large delamination was observed after the power cycle test, indicating that the Cu-Ag composite material exhibit remarkable potential in SiC power devices packaging. & COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).