Micro-Computed Tomography Measurements in Electronics

Synopsis

Electronic components may be subjected to significant deformation under the action of thermal and mechanical loads during operation and storage.  The use of thin material layers in addition to fine embedded interconnects limits the possibilities for the integration of sensors to measure deformation and strain.  Previously, deformations in in electronic components and assemblies have been measured using optical methods including moiré interferometry and digital image correlation – both of which require the cross-sectioning of the solder joint to gain access to the joint of interest for the purpose of strain and deformation measurement.  Cross-sectioning is an invasive technique which requires discarding a portion of the package.  In addition, the measurements are often limited to line of sight allowing measurement of only the optically visible cut-section.  In this research area, methods are being studied for non-contact measurement of displacements in electronics layers and interconnects, non-invasively using a combination of x-ray computed tomography and digital volume correlation.  The new class-of-methods does not require cross-sectioning of the part for the purpose of deformation and strain measurement.  In addition, the measurements are not limited to the joints in the line of sight.

Representative Publications

1. 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;
2. Lall, P., M. Kasturi, J. Suhling, and D. Locker, Stress Strain Analysis on Stitch Bond of Cu-Al Wirebonds Using X-ray Micro-CT Technique, in Proceedings of the IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, Las Vegas, NV, pp. 841-846, May 28-31, 2019.
3. Lall, P., N. Kothari, S. Deshpande, and L. Nguyen, Study of the Effect of Solder-Joint Voiding using X-ray MicroCT Data-based FE Models with Experimental Validation, in Proceedings of the Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, Las Vegas, NV, pp. 1160-1167, May 28-31, 2019.
4. Lall, P., and K. Goyal, Reliability of SAC305 Solder Interconnects on Double – Sided Flexible Printed Circuit Board Using X-Ray Micro-CT, in Proceedings of the ASME Interpack 2017, California, pp. 1-7, August 29 – September 1, 2017.
5. Lall, P., and J. Wei, X-ray Micro-CT and DVC Based Analysis of Strains in Metallization of Flexible Electronics, in Proceedings of the 16th ITherm, Orlando, FL, pp. 1253-1261, May 30 – June 2, 2017.
6. Lall, P., Wei, J., Remaining Useful Life Assessment of Field Deployed Electronics Using X-ray Micro-CT Based Digital Volume Correlation and Finite- Element Analysis, Proceedings of the 66th ECTC, Las Vegas, Nevada, pp. 1583- 1593, May 31- June 3, 2016.
7. Lall, P., Wei, J., PBGA Package Finite Element Analysis Based on the Physical Geometry Modeling Using X-ray Micro-CT Digital Volume Reconstruction, Proceedings of the ITHERM 2016, Las Vegas, Nevada, pp. 285- 295, May 31- June 3, 2016.
8. Lall, P., and J. Wei, X-Ray Micro- CT and Digital- Volume Correlation Based Three- Dimensional Measurements of Deformation and Strain in Operational Electronics, Proceedings of the 65^th ECTC, San Diego, CA, pp. 406-416, May 26-29, 2015
9. Lall, P., Wei, J., LED Chip Deformation Measurement During the Operation Using the X-ray CT Digital Volume Correlation, Paper IPACKICNMM2015-48785; Session 14-5-1, ASME International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems (InterPACK), San Francisco, CA, pp. 1-6, July 6-9, 2015
10. Lall, P., Deshpande, S., Wei, J., Suhling, J., Non-Destructive Crack and Defect Detection in SAC Solder Interconnects Using Cross-Sectioning and X-Ray Micro-CT, Electronic Components and Technology Conference, 64th ECTC, pp. 1449-1456, Orlando, FL, May 27-30, 2014.