Effect of Pre-Annealing Time of Ti/Ag Metallized Cu Substrate on Ag-Ag Direct Bonding for SiC Die Attach

초록

The effect of pre-annealing time on Ti/Ag metallized Cu substrates on Ag-Ag direct bonding was investigated for SiC die-attach applications. For Ag-Ag joints bonded at 250 °C under 10-20 MPa for 5 min, the shear strength increased from 11.2 MPa for joints fabricated using non-annealed substrates to 42.9 MPa and 45.0 MPa for those prepared using pre-annealed substrates, depending on the pre-annealing time. For Ag-Ag joints bonded at 200 °C under 1.1 MPa for 60 min, the shear strength similarly increased from 15.5 MPa for joints fabricated using non-annealed substrates to 50.5 MPa and 52.5 MPa for joints prepared using pre-annealed substrates. These improvements indicated preformed Ag hillocks enhanced interfacial contact and provided favorable pathways for atomic transport during bonding. This study demonstrates that substrate pre-annealing is a promising approach for achieving enhanced Ag-Ag direct bonding under relaxed bonding conditions for wide-bandgap power device packaging. © 2026 Japan Institute of Electronics Packaging.

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