Effect of Sintering Conditions on the Mechanical Strength of Cu-Sintered Joints for High-Power Applications

Abstract

In this study, the feasibility of low-cost Cu-sintering technology for power electronics packaging and the effect of sintering conditions on the bonding strength of the Cu-sintered joint have been evaluated. A Cu paste with nano-sized Cu powders and a metal content of ~78% as a high-temperature bonding material was fabricated. The sinter-bonding reactions and mechanical strengths of Cu-sintered joints were evaluated at different sinter bonding pressures, temperatures, and durations during the sintering process. The shear strength of the Cu-sintered joints increased with increasing sintering pressure. Good interfacial uniformity and stable metallurgical microstructures were observed in the Cu joints sintered at a high sintering pressure of 10 MPa, irrespective of the sintering time. It was confirmed that a high-pressure-assisted sintering process could create relatively dense sintered layers and good interfacial uniformity in the Cu-sintered joints, regardless of the sintering temperatures being in the range of 225–300 °C. The influence of the sinter bonding pressure on the shear strengths of the Cu-sintered joints was more significant compared to that of the sintering temperature. Durations of 10 min (at 300 °C) and 60 min (at 225 and 250 °C) are sufficient for complete sintering reactions between the Si chip and the direct bond copper (DBC) substrate. Relatively good metallic bonding and dense sintered microstructures created by a high sintering pressure of 10 MPa resulted in high shear strength in excess of 40 MPa of the Cu-sintered joints.

In-air sintering of copper nanoparticle paste with pressure-assistance for die attachment in high power electronics

“…The vaporized organic additives and the air are partially removed with the assistance of low pressure, thereby resulting in the exposure of the Cu NP surfaces. This facilitated the diffusion of Cu atoms between the particles, which induced the formation of sintering necks [33][34][35][36]. Since the sintering was performed at a relatively high temperature in air, the surfaces of the Cu NPs underwent slight oxidation.…”

Influence of Structure Development on Performance of Copper Composites Processed via Intensive Plastic Deformation

“…The majority of commercially produced metallic materials are fabricated by casting, although techniques such as powder metallurgy (PM) [ 1 , 2 , 3 ], sintering (of various types) [ 4 , 5 , 6 ], mechanical alloying [ 7 , 8 , 9 ], and additive manufacturing [ 10 , 11 , 12 ] are also favored. Fabricating a bulk material from initial powders is advantageous as it supports the achievement of fine grain size and thus provides the materials with improved properties [ 13 , 14 ].…”

Distortion prediction during sintering using Monte Carlo method implemented with virtual springs

“…Sintering techniques have progressed with the diversification of components in electronics and with technological advancements. In particular, electronic components [1][2][3][4] such as multilayer ceramic capacitors and die bonding for power semiconductors have been downsized. As a result, such components comprise only countable layers, and thus, the analysis of behavior of individual particles in the layers has become increasingly important.…”