Dependence of overcurrent failure modes of IGBT modules on interconnect technologies

Abstract

The networked conductive phases within the solidification structure and the Sn-3.5Ag filled in the cracks within the residual Si IGBT are responsible for forming the conducting paths in the tested samples. Both liquid phase and gas phase can be formed and the highest temperature can reach the boiling point of Si even if the sandwich structure IGBT sample is tested with short circuit failure mode.

Packaging Solution for SiC Power Modules with a Fail-to-Short Capability

“…7 exhibit a fail-to-short behaviour, with a failure resistance of usually less than 200 mΩ, independently of the energy which caused the failure. On the contrary, despite being encapsulated in a solid material (epoxy), the un-clamped module (C) This means that the fail-to-short behaviour requires two key elements: a large, solid interconnect system (standard wirebonds can only manage a very low energy levels [4]), but also a strong mechanical support to prevent the module from exploding.…”

“…To prevent the failure of a single module from stopping the operation of a whole converter, a fail-to-short behavior is expected [1], so that the failing power modules basically "disappear" from the series string. Fail-to-short power modules have been demonstrated for silicon devices [2], [3], [4]. They are all based on massive interconnects (such as in press-packs [5]), as opposed to the wirebond interconnects used in standard power modules (wirebonds act as fuses, resulting in an open-circuit behavior in case of failure).…”

Design and Experimental Validation of a Wire-Bond-Less 10-kV SiC MOSFET Power Module

“…This type of structure allows for increased power density, and reduces the parasitic inductances and capacitances in the module, thereby improving the transient performance. Furthermore, by eliminating the wire bonds, the energy absorption capability during faults is increased, as shown in [85]. This structure also allows decoupling capacitors to be embedded within the module to further improve the dynamic performance without increasing the module footprint.…”

Interconnect Materials Enabling IGBT Modules to Achieve Stable Short-Circuit Failure Behavior

“…During the test, the capacitor bank was charged to a specified energy level of 750 J (charging voltage 156 V). Such an energy level has been selected as per a previous estimation that each IGBT in IGBT power modules would face in real industrial applications [12]. The test was triggered enabling (all the energy stored in the capacitor bank to) discharge through the device inducing thermal overload failure.…”

“…In a previous paper [12], the dependence of failure mode of the IGBT modules on the different interconnect technologies were investigated using overcurrent test powered with a capacitor bank. The present work is concerned with the selection of interconnect materials for both die attachment (DA) and top side insert (TSI) material.…”