THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, December 3, 2019

9:00 AM
in GTMI 431

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Kashyap Mohan

"Design and Demonstration of Sintered Nanoporous Copper Die-Attach Interconnections with Superior Electrical, Thermal, and Reliability Performances over Sintered Silver”

 Committee Members:

Prof. Rao Tummala, Advisor, MSE

Prof. Antonia Antoniou, Co-Advisor, ME

Dr. Vanessa Smet, ECE

Prof. Naresh Thadani, MSE

Prof. Preet Singh, MSE

Abstract:

To address the demand for higher electrification and efficiency in automobiles and aviation, there is an increasing focus on developing new power electronics packaging technologies which can enable the wide-bandgap devices to operate at their full potential. In particular, new die-attach interconnection materials are needed with thermal stability at temperatures greater than 250°C, superior thermal and electrical conductivities for higher thermal dissipation and power handling, and higher mechanical reliability as the thermal stresses due to CTE mismatch in the package are expected to increase with the increase in temperature cycling range.

This research proposes low-temperature, low-pressure sintering of nanoporous copper (Cu) films to form all-Cu die-attach joints as the next-generation die-attach technology capable of addressing the above-mentioned challenges. To realize the above objective, three research tasks are proposed and results for the tasks are discussed. The first task details the design and fabrication of nanoporous Cu by chemical dealloying of electroplated Cu-Zn alloys. In the second task, the effect of the morphology of nanoporous Cu films on their sintering kinetics is explored, followed by the development of assembly parameters to form good metallurgical bonds with bulk-Cu interfaces. The third and final task proposes to investigate the thermomechanical reliability of sintered Cu joints at elevated temperatures.