A high-temperature-resistant die attach material based on Cu@In@Ag particles for high-power devices

This paper presents a high-temperature-resistant preform based on Cu@In@Ag particles that can be used as a die attach material for high-power devices, using an electroless method to achieve the preparation of core-shell structure particles. Indium has a lower melting point of 156.6 degrees C and can be completely consumed to form intermetallic compounds of Cu2In, Ag9In4, and Ag3In, which will raise the melting point of the solder joint to over 400 degrees C. The silver coating is intended to enhance the oxidation resistance of the Cu@In particles and to improve the service reliability of the solder joint. It was demonstrated that high-temperature-resistant solder joints could be obtained by reflowing at 200 degrees C for 15 min under a pressure of 10 MPa. The shear strengths of solder joints were 29.70 MPa and 21.85 MPa at 25 degrees C and 300 degrees C, respectively. The thermal and electrical properties of the solder joints after reflow composed of Cu@In@Ag core-shell particles were tested and the thermal conductivity was 79.02 W/m K and 58.64 W/m K at 30 degrees C and 250 degrees C, respectively. Great electrical and thermal conductivity and high shear strength at high temperatures result in high-temperature reliability. As a high-temperature-resistant die attachment material, it has the potential to be used in die attachment in high-power equipment modules.