Rapid sintering by thermo-compression in air using a paste containing bimodal-sized silver-coated copper particles and effects of particle size and surface finish type

To rapidly form a highly thermal-conductive line structure that could be sustained even at high temperatures such as 300 degrees C, the compression (5 MPa)-assisted sintering of a Ag-finished die on an Ag-finished substrate was performed in air employing a paste containing bimodal-sized Ag-coated Cu (Cu@Ag) particles at a ratio of 6 (1.5 mu m):4 (800, 400, and 200 nm). The 20 0-nm particles among the submicrometer-sized particles provided the most enhanced sinterability on both joint strength and microstructure. Accordingly, the 1.5-mu m/200-nm Cu@Ag paste exhibited excellent shear strength surpassing 20 MPa, accompanied with a near full-density structure, even by the short sintering for 3 min. The strength eventually exceeded 45 MPa after 10 min. These results demonstrate the successful development of an effective paste to achieve rapid sintering even in air with low material cost. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study demonstrates the successful development of an effective paste that can rapidly form a highly thermal-conductive line structure. By using a paste containing Cu@Ag particles in air, excellent shear strength and microstructure can be achieved in a short period of time, showing rapid sintering with low material cost.