Abstract:
Standard packaging and interconnection technologies
limit the maximal junction temperature (Tjmax) to about 150°C at
present. This restriction is caused by the limited power cycling
capabilities of Al bond wires and of soft solder joints. Important
applications of power devices, however, require operating
temperatures of 175°C or even 200°C.
To evaluate the suitability of the Low Temperature Joining
Technique (LTJT) for future module set-up, test samples were
prepared and investigated. Already the replacement of only the
chip-to-substrate solder joint (one-sided LTJT) improved the
power cycling capability at ∆Tj=130K five times or at a ∆Tj=156K
ten times compared to the expected capability of soldered and
wire bonded devices at these conditions. Application of LTJT to
top side chip connections also, i.e. additional replacement of bond
wires by silver stripes joined by LTJT (double-sided LTJT),
yielded a further increase of power cycling capability.
