Microstructure and Bonding Properties of Transient Liquid-Phase Bonding using Cu-SnAgCu Molded Sheets By High-Pressure Powder Compression

초록

We propose a bonding technology for transient liquid-phase (TLP) materials using Cu-SnAgCu (SAC) molded sheets, which are a mixture of spherical Cu and SAC particles, for high-temperature die-attach applications. The powder-compressed Cu-SAC molded sheet had a dense internal structure with minimal internal voids and a smooth surface. The Cu-SAC molded sheets were bonded at a bonding temperature of 300 degrees C, bonding time of 20 min, and pressure of 5 MPa under a formic acid atmosphere. The Cu-SAC molded sheet exhibited minimal voids within the sheet and at the bonding interface, and the microstructure between the Cu particles and specimen was composed of intermetallic Cu3Sn. Consequently, the sheet achieved average shear strength of 50.5 MPa, which is a stable bonding strength under TLP bonding conditions, demonstrating its potential as a high-temperature die-attach material.

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