Copper-Aluminum Wirebond Interconnects

Synopsis

Automotive electronics is migrating to copper, palladium-coated copper and silver wire for wirebonding.  Copper and Silver wire is finding increasing applications in high power electronics operating at 50V-300V used for propulsion, transmission and control in emerging hybrid electric (HEV) and electric vehicles (EV).  Potential advantages of transition to Cu-Al wire bond system includes low cost of copper wire, lower thermal resistivity, lower electrical resistivity, higher deformation strength, damage during ultrasonic squeeze, and stability compared to gold wire. However, the transition to the copper wire brings along some trade-offs including poor corrosion resistance, narrow process window, higher hardness, and potential for cratering.  Research focuses on development of corrosion life prediction models during operation at high voltage at extreme temperatures.

Representative Recent Publications

1. Lall, P., and S. Jung, Reliability Assessment of Cu-Al WB under Automotive Temperatures in Presence of Ionic Contamination and Voltage Bias, in Proceedings of the InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp. 880-890, May 31-June 3, 2022.
2. Lall, P., Kasturi, M., Kothari, N., and Locker, D., X-Ray Microcomputed  Tomography Based FE-Models to Capture Realistic Manufacturing Variability in Cu-Al Wirebonds and Solder-Joints in QFNs, Proceedings of SMTAI, pp. 1-13, Sept 22-26, 2019
3. Lall, P., Deshpande, S., Nguyen, L., Comparison of Reliability of Copper, Gold, Silver and PCC Wirebonds under Sustained Operation at 200°C, Proceedings of the SMTAI Conference, pp. 1-13, Rosemont, IL, Oct 14-18, 2018
4. Lall, P., Y. Luo and L. Nguyen, Numerical Multiphysics Model for Cu-Al Wire Bond Corrosion Subjected to Highly-Accelerated Stress Test, in Proceedings of ECTC, San Diego,CA, US, pp. 1622-1633, May 29-June 1, 2018.
5. Lall, P., Deshpande, S., Nguyen, L., Copper, Silver, and PCC Wirebonds Reliability in Automotive Underhood Environments [IPACK2018-8358], Proceedings of the ASME InterPACK2018, San Francisco, CA, pp. 1-13, August 27-30, 2018.
6. Lall, P., Deshpande, S., Nguyen, L., Development of Model for Identification of Process Parameters for Wet Decapsulation of Copper-Aluminum Wirebond in PEMs, IEEE Transactions on Components, Packaging and Manufacturing Technology, Volume 7, Issue 8, pp. 1280-1292, August 2017
7. Lall, P., Deshpande, S., L. Nguyen, M. Murtuza, Microstructural Indicators for Prognostication of Copper–Aluminum Wire Bond Reliability Under High-Temperature Storage and Temperature Humidity, IEEE Transactions on Components, Packaging and Manufacturing Technology, Vol 6, No. 4, pp. 569 – 585, 2016.
8. Lall, P., Luo, Y., Nguyen, L., Multiphysics Life-Prediction Model Based on Measurement of Polarization Curves for Copper-Aluminum Intermetallics, Proceedings of the 66th ECTC, Las Vegas, Nevada, pp. 1027- 1039, May 31- June 3, 2016.
9. Lall, P., Deshpande S., Nguyen, L., Principal Components Regression Model for Prediction of Acceleration Factors for Copper- Aluminum Wirebonds Subjected to Harsh Environments, Proceedings of the 66th ECTC, Las Vegas, Nevada, pp. 637- 648, May 31- June 3, 2016.
10. Lall, P., Luo, Y., Nguyen, L., De-Bonding Simulation of Cu-Al Wire Bond Intermetallic Compound Layers, Proceedings of the ITHERM 2016, Las Vegas, Nevada, pp. 862-871, May 31- June 3, 2016.