In this paper, the process development and reliability of novel copper preforms are presented, which while offering a substantially reduced manufacturing footprint, ensure enhanced reliability, high thermal conductivity, excellent thermo-mechanical fatigue resistance and most importantly, the capability to realise a single material system for top side of the die, die-attach and the substrate attach while sintering at 250°C for 5min with 20MPa sintering pressure. Such kind of a novel approach does not exist in the industry today and the reliability of such a set-up is discussed through power-cycling and high-stress thermal shock analysis.
The SiC devices assembled through this process show no failures even after 500000 cycles through power cycling and zero delamination after 1000 thermal shock cycles at +150/-40°C with a 5min dwell time, tested in a two-chamber thermal shock chamber (air-air conditions).