Copper Die-Bonding Sinter Paste: Sintering and Bonding Properties

Abstract

this paper describes the sintering properties and bonding properties of copper (Cu) die-bonding sinter paste for power devices operating at high temperatures. The Cu paste can be sintered pressure less in 100% H2 or under pressure in 100% N2 atmospheres. The as-sintered density, thermal conductivity and resistivity of pressure less-sintered Cu (in 100% H2, 300 °C, 1 h) is found to be 7S%, 180 Wm^-1K^-1 and 4.3 $\mu\Omega\cdot cm$, respectively. The pressurelesssintered Cu has higher 0.2% proof stress than the pressure-sintered Ag (sintered density =87%, in air, 300 °C 10 MPa, 10min) as a comparison material in a three-point bending test. The die-shear strength of appropriate pressurelesssintered Cu on four different metal adherends (Cu, Ni, Ag and Au) was 30 MPa or higher. The die-shear strength of pressure- sintered Cu in 100% N2 was 36 MPa or higher. A thermal cycle tolerance of 1000 cycles or greater was shown in a power device test package which was bonded using the pressurelesssintered Cu and encapsulated with an epoxy molding compound. The Cu sinter paste can be used as a reliable die-bonding material for power modules operating at high temperatures.