27 4 August, 2015
Ag Sintering III – 0-hr & Reliability Results
Oxidation and/or delamination of interfaces is common,
even at 0-hr, lowering adhesion and electrical & thermal
performance. Potential solutions (not yet proven):
Reduce oxygen content in atmosphere during curing
Change paste formulation to allow for lower sintering
temperature or less interaction with back-side metallization
Change back-side metallization
In cases with no delamination, high DSS (20 N/mm
2
) and
good thermal performance can be had with Ag finishes
In-package electrical performance still lags Pb-solder
No test configuration has yet to pass all required reliability
tests after MSL1 preconditioning
Results after MSL3 preconditioning are better, with
reduced cracking and delamination
Recent results show further improvements,
but still some delamination after temperature cycling and
pressure pot / autoclave tests
but failures during biased tests (THB, HAST) are common
Physics of failure understanding missing/ongoing: already
porosity and bond line thickness changes seen
Die penetration test shows non-hermetic die attach (at
least for ~1mm from the edges of the die)
Delamination
Copper oxide
LF
Ag-plating
Ag-sinter material
Die
Ag-sinter material