Investigation of Lateral Die Crack Failure at Reliability Test

Abstract

"Goes Green & Copper", is the strategy to introduce 1) environmentally friendly materials to meet RoHS (Restriction of the use of Hazardous Substances) & WEEE (Waste Electrical & Electronic Equipment) requirements and 2) Cu wires for superior electrical, mechanical & intermetallics properties compared to Au wires. A complete package level qualification was planned to assess the reliability performaces in discrete packages. This paper will discuss in details on investigation of lateral die crack failure during reliability. Process & materials investigation revealed that interaction of leadframe paddle construction, die attach method, die construction & mold compound factors play important role in aggravating lateral die crack. FEA (finite element analysis) was performed to understand the thermo-mechanical stress distribution within the die & package. Re-qualification was performed & reliability results showed that lateral die crack failure could be eliminated with proper combination of BOM selection.