CALCE’s commitment to the application of physics-of-failure-based principles in material and device research, its research archive of over 25 years, as well as its track record in assisting its members in understanding the limits and uses of new technologies make CALCE an attractive collaborative partner. CALCE has a strong track record helping the automotive industry, and its work with both automotive and aerospace electronics manufacturers provides a respected forum for addressing critical issues and challenges facing the automotive industry.

For more information on the CALCE Electronic Product and Systems Center, please visit http://www.calce.umd.edu/consortium.html.

In 2013, Wei He, a Ph.D. candidate advised by Prof. Pecht, co-oped with the Energy Modeling, Control and Computation Team at the Bosch Research and Technology Center in California for 6 months. Wei's role was focused on the development and design of battery management software functions and advanced battery models. In particular, he developed an efficient numerical solution for a system of algebraically coupled partial differential equations in an electrochemical model of a Li-ion battery for use in a real-time battery management system. He also developed a cumulative numerical integration scheme needed in the software. He selected the Clenshaw-Curtis integration scheme based on its ease of computation and generalized the method to perform cumulative integration to each of its nodes. He also implemented a reduced-order electrochemical battery model in Matlab/Simulink, and ran the models in dSPACE for use in the hardware in the loop validation of battery management systems.

Dae-Suk Kim, a Ph.D. student advised by Prof. Bongtae Han, co-oped with the AE/EDT3 Team at Robert Bosch GmbH in Germany for the summer in 2013. Dae-Suk’s research was focused on validation and calibration of an FEA model developed for electronic control units. In this work, he utilized a high sensitivity in-plane displacement technique called moiré interferometry. In particular, he successfully implemented this technique for a very large surface area as well as for extreme temperature conditions encountered in the automotive applications, which has been a challenge in implementing this high sensitivity technique. Accuracy of less than a micron displacement was achieved by the numerical model through verification and calibration.

If you are interested in sponsoring an internship, please contact  Prof. Michael Pecht.

The End of Life Vehicle Directive 2011/37/EU in the European Union require automobile manufacturers to eliminate lead-based products from automotive electronics by January 2016. With regard to lead elimination from electronics, CALCE has performed extensive research and testing on lead-free electronics since early 2000s. The reliability of tin-based solders, such as SAC305, SnAg, and SN100C, and other low silver tin-based alloys have been determined and benchmarked against eutectic tin-lead solder under harsh operating conditions, including automotive applications [1][2][3][4]. Models for predicting the failure of interconnects formed with these solders have been devised and validated. Furthermore, CALCE is continuing to develop models to enable the prediction of next-generation solders as they are being proposed. One of the current challenges with the use SAC305 solder has been that SAC305 soldered assemblies tend to exhibit poor performance compared with SnPb under vibration and shock loading. As a result, alternative alloys are still being investigated, and underfill and staking of parts to improve shock and drop performance are being considered.

In addition to solder interconnects, CALCE is examining the impact of process temperature and material changes on printed wiring board reliability. The printed wiring board provides electronic connectivity and isolation of electric circuits formed to provide desired functions. Property changes [5][6], conductive anodic filament formation [7][8], and creep corrosion of lead-free finished copper pads [9][10] for printed wiring boards present failure risks for automotive electronics. CALCE research has quantified these changes and their corresponding risks.

In addition to the change in solder material, the removal of lead in electronics has also raised concern regarding the failure risk presented by tin whiskers. Tin whiskers, which are conductive filament structures that spontaneously form on tin finished surfaces, are another reliability concern for automotive electronics. Since tin whiskers are conductive, their formation can create unintended electrical failures such as short circuits. Since 2007, CALCE has hosted seven international symposia on the topic of tin whiskers. Further, studies at CALCE have shown the formation of tin whiskers on automotive electronic throttle controls and engine controls unit, necessitating control plans for the use or prohibition of tin-based finishes in automotive applications [11][12]. CALCE studies have provided key insights into the reliability issues faced by the automotive industry and have provided various recommendations to manufacturers and National Highway Traffic Safety Administration to resolve those problems.

CALCE has a long history of applying a physics-of-failure-based philosophy to product qualification. The application of the physics-of-failure is a key approach for establishing test requirements for products to assure life expectancy. Physics-of-failure is used to identify failure mechanisms that are active throughout a product’s life cycle and determine acceleration factors to quantitatively relate life cycle conditions to testing. To facilitate physics-of-failure-based qualification, shorten design cycles, and improve overall product reliability, CALCE has developed virtual qualification. Virtual qualification involves using computer-assisted modeling and simulation based on the physics-of-failure. CALCE’s Simulation Assisted Reliability Assessment (calceSARA^®) software is used to assess the life expectancy of electronic hardware under anticipated life cycle loading conditions, as well as under accelerated stress test conditions [13]. The assessment of life expectancy under anticipated life cycle loading conditions is referred to as the virtual qualification (VQTM) process. CALCE has carried out virtual qualification of various electronic parts and assemblies used in automobiles [26]. Accelerated experimental tests have also been conducted to verify whether a product has met or exceeded its intended quality and reliability requirements.

In addition to physics-of failure-based qualification, CALCE has assisted automotive manufacturers with work on micro-electro-mechanical systems (MEMS), silicon carbide semiconductors, as well as power and high temperature electronics. Secondary battery systems are increasingly used in automotive vehicles to reduce carbon output, and hybrid-electric and electric vehicles are touted as the future of the automotive industry, with their sales gaining ground across the world. However, vehicle fires due to battery failures have been reported in the news, which indicates the need for a better understanding of the root-causes of battery failures. Another major impediment hindering the popularity of hybrid-electric and electric vehicles is "range anxiety." The CALCE Battery Team at the University of Maryland, College Park, has been developing approaches to improve the safety, reliability, and performance of automobile batteries. The team is examining battery degradation and shorting failure mechanisms as well as developing physics-based battery models, prognostic and diagnostic algorithms, online sensing techniques, and optimal control strategies. CALCE has been conducting extensive and thorough evaluation of battery life through state of charge and state of health estimation to address the issue of range anxiety [14-18]. In addition, various prognostic techniques are being employed to evaluate the reliability and remaining useful life of automotive batteries [19-24].

Prof. Bongtae Han and his Ph.D. student, Dae-Suk Kim, together with engineers at Robert Bosch GmbH, have successfully implemented a high displacement measurement technique under extreme temperature conditions for model calibration. The figure shows the y-direction displacement field obtained from the FEM (left) and fringe pattern obtained at -30°C by moiré interferometry (right). With the high sensitivity (contour interval of 417 nm) and high quality displacement field provided by moiré interferometry, correlation within one micron was achieved at the extreme temperatures. As a part of this collaboration, Dae-Suk Kim interned with the AE/EDT3 team at Robert Bosch GmbH in Germany for 2 months in 2013. The team will continue to work on prognostics and health management of electronic control modules through CALCE.

To learn more, please contact Prof. Bongtae Han.

In one design assessment, the vibration module of the software was used to resolve component selection and placement issues that would have led to reduced product life. In the same design, the thermal analysis module was used to optimize localized metallization, leading to reduced component temperatures and extended life. Subsequent comparison of design verification results of comparable designs realized a 10% reduction in design time and an 83% reduction in permanent failures.

To learn more about the calceSARA® software, please visit the calceSARA information page or contact Dr. Michael Osterman.

On September 16-19, 2014, CALCE and Buehler will jointly offer a four-day course on failure analysis of electronics at the University of Maryland, College Park campus. To date, over 200 engineers from leading companies, including automotive manufacturers and suppiliers, from around the world have taken this course.

With a combination of classroom instruction, case studies, demonstrations, and hands-on laboratory training, this course covers topics ranging from failure mechanisms in electronics to specimen preparation, physics of failure, reliability, root cause analysis methodology, and materials analysis techniques.

For more information and to register, please visit http://www.calce.umd.edu/facourse/.

1. C. O'Connor, K. Nathan, and P. McCluskey, Evaluating the Performance and Reliability of Embedded Computer Systems for Use in Industrial and Automotive Temperature Ranges, Intel Developer Network News, Vol. 1, pp. 62-65, 2001.
2. E. George, D. Das, M. Osterman, and M. Pecht, Thermal Cycling Reliability of Lead-Free Solders (SAC305 and Sn3.5Ag) for High-Temperature Applications, IEEE Transactions on Device and Materials Reliability, vol.11, no.2, pp.328-338, June 2011.
3. Choubey, J. Wu, S. Ganesan, and M. Pecht, Lead-Free Assemblies in High Temperature Applications, Proceeding of IMAPS International Conference on High Temperature Electronics (HITECH 2006), pp. 384-389, May 2006.
4. E. George, M. Osterman, M. Pecht, R. Coyle, R. Parker, and E. Benedetto, Thermal Cycling Reliability of Alternative Low-Silver Tin-based Solders, 46th International Symposium on Microelectronics, Orlando, Florida, US, 29 September-3 October, 2013.
5. R. Sanapala, B. Sood, D. Das, and M. Pecht, Effect of Lead-Free Soldering on Key Material Properties of FR-4 Printed Circuit Board Laminates, IEEE Transactions on Electronics Packaging Manufacturing, Vol. 32, No. 4, pp. 272-280, October 2009.
6. B. Sood, R. Sanapala, D. Das, M. Pecht, C. Huang and M. Tsai, Comparison of Printed Circuit Board Property Variations in Response to Simulated Lead-Free Soldering, IEEE Transactions on Electronics Packaging Manufacturing, Vol. 33, No. 2, pp. 98-111, April 2010.
7. K. Rogers and M. Pecht, A Variant of Conductive Filament Formation Failures in PWBs with 3 and 4 mil Spacings, Circuit World, Vol. 32, No. 3, pp. 11-18, 2006.
8. B. Sood and M. Pecht, Conductive Filament Formation in Printed Circuit Boards – Effects of Reflow Conditions and Flame Retardants, 35th International Symposium for Testing and Failure Analysis(ISTFA 2009), San Jose, CA, November 15-19, 2009.
9. S. Zhang, M. Osterman, A. Shrivastava, R. Kang and M. Pecht, The Influence of H2S Exposure on Immersion-Silver-Finished PCBs Under Mixed-Flow Gas Testing, IEEE Transactions on Device and Materials Reliability, Vol.10, No.1, pp. 71-81, March 2010.
10. Y. Zhou and M. Pecht, Investigation on Mechanism of Creep Corrosion of Immersion Silver Finished Printed Circuit Board by Clay Tests, 55th Annual IEEE Holm Conference, Vancouver, British Columbia, Canada, pp. 321-330, September 14-16, 2009.
11. E. George, M. Pecht, Tin whisker analysis of an automotive engine control unit, Microelectronics Reliability, Volume 54, Issue 1, Pages 214-219, January 2014 .
12. B. Sood, M. Osterman and M. Pecht, Tin Whisker Analysis of Toyota's Electronic Throttle Controls, Circuit World, Vol. 37, No. 3, pp. 4-9, 2011.
13. W. Wang, M.H. Azarian, and M. Pecht, Qualification for product development, Electronic Packaging Technology & High Density Packaging, ICEPT-HDP 2008. International Conference, pp.1-12, July 28-31, 2008.
14. N. Williard, B. Sood, M. Osterman, and M. Pecht, Disassembly methodology for conducting failure analysis on lithium–ion batteries, Journal of Material Sciences: Material Electron (2011) Vol. 22, pp.1616–1630, 2011.
15. W. He, N. Williard, C. Chen and M. Pecht, State of charge estimation for electric vehicle batteries using unscented kalman filtering, Microelectronics Reliability, Vol. 53, Issue 6, pp. 840-847, June 2013.
16. D. Liu, J. Pang, J. Zhou, Y. Peng and M. Pecht, Prognostics for state of health estimation of lithium-ion batteries based on combination Gaussian process functional regression, Microelectronics Reliability, Vol. 53, Issue 6, pp. 832-839, June 2013.
17. N. Williard, W. He, and M Pecht, Model Based Battery Management System for Condition Based Maintenance, MFPT 2012 Proceedings, 2012.
18. Y. Xing, E. W. M. Ma, K. L. Tsui and M. Pecht, Battery Management Systems in Electric and Hybrid Vehicles, Energies,Vol. 4, pp. 1840-1857, 2011.
19. Q. Miao, L. Xie, H. Cui, W. Liang and M. Pecht, Remaining useful life prediction of lithium-ion battery with unscented particle filter technique, Microelectronics Reliability, Vol. 53, Issue 6, pp. 805-810, June 2013.
20. Y. Xing, E. W.M. Ma, K-L. Tsui and M. Pecht, An ensemble model for predicting the remaining useful performance of lithium-ion batteries, Microelectronics Reliability, Vol. 53, Issue 6, pp. 811-820, June 2013.
21. W.He, N. Williard, M. Osterman, M. Pecht, Prognostics of lithium-ion batteries based on Dempster–Shafer theory and the Bayesian Monte Carlo method, Journal of Power Sources, Vol. 196, pp. 10314– 10321, 2011.
22. W. He, N. Williard, M. Osterman, and M. Pecht, Remaining Useful Performance Analysis of Batteries, IEEE: International Prognostics and Health Management Conference, Denver CO, June 21-23, 2011.
23. W. He, N. Williard, M. Osterman, and M. Pecht, Prognostics of Lithium-ion Batteries using Extended Kalman Filtering, IMAPS Advanced Technology Workshop on High Reliability Microelectronics for Military Applications, Linthicum Heights, MD, May 17-19, 2011.
24. N. Williard, W. He, M. Osterman, M. Pecht, Predicting Remaining Capacity of Batteries for UAVs and Electric Vehicle Applications, IMAPS Advanced Technology Workshop on High Reliability Microelectronics for Military Applications, Linthicum Heights, MD, May 17-19, 2011.
25. K. Upadhyayula and A. Dasgupta, Physics-of-Failure Guidelines for Accelerated Qualification of Electronic Systems, Quality And Reliability Engineering International, Vol. 14, pp 433-447, 1998.
26. M. Osterman, A. Dasgupta, and T. Statderman, Simulation Guide Testing in Product Qualification and Development in Case Studies in Reliability and Maintenance, Wallace R. Blischke (Editor), D. N. Prabhakar Murthy (Editor), John Wiley, December 2002.
27. A. Kleyner and P. Sandborn, Minimizing Life Cycle Cost by Managing Product Dependability via Validation Plan and Warranty Return Cost, International Journal of Production Economics, Vol. 112, No. 2, pp. 796-807, April 2008.
28. M. Pecht, A. Ramakrishnan, J. Fazio, and C.E. Nash, The Role of U.S. National Highway Traffic Safety Administration in Automotive Electronics Reliability and Safety Assessment, IEEE Trans. on Components and Packaging Technologies, Vol. 28, No. 3, pp. 571-580, Sept. 2005.
29. C. Castelli, C. Nash, C. Ditlow, and M. Pecht, Sudden Acceleration - The Myth of Driver Error, CALCE Press, University of Maryland, College Park, MD, 2003.
30. D. A. Thomas, K. Ayers, and M. Pecht, “The ‘Trouble Not Identified’ Phenomenon in Automotive Electronics,” Microelectron. Reliab., 42(4–5), pp. 641–651, 2002.
31. E. Habtour, C. Cholmin, M. Osterman, and A. Dasgupta, Novel Approach to Improve Electronics Reliability in the Next Generation of US Army Small Unmanned Vehicles under Complex Vibration Conditions, ASM International Journal Failure Analysis and Prevention, Vol. 12, pp. 86-95, 2012.
32. J. Gu, D. Barker, and M. Pecht, Health Monitoring and Prognostics of Electronics Subject to Vibration Load Conditions, IEEE Sensors Journal, Vol. 9, No. 11, pp. 1479-1485, Nov. 2009.
33. H. Qi, M. Osterman, and M. Pecht, A Rapid Life-Prediction Approach for PBGA Solder Joints Under Combined Thermal Cycling and Vibration Loading Conditions, IEEE Transactions on Components and Packaging Technologies, Vol. 32, No. 2, pp. 283-292, June 2009.
34. H. Qi, M. Osterman, and M. Pecht, Design of Experiments for Board-Level Solder Joint Reliability of PBGA Package under Various Manufacturing and Multiple Environmental Loading Conditions, IEEE Transactions on Electronics Packaging Manufacturing, Vol. 32, No. 1, pp. 32-40, Jan. 2009.
35. Y. Zhou, M. Al-Bassyiouni, and A. Dasgupta, Harmonic and Random Vibration Durability of SAC305 and Sn37Pb Solder Alloys, IEEE Transactions on Components and Packaging Technologies, Vol. 33, No. 2, pp. 319-328, June 2010.
36. H. Qi, S. Ganesan and M. Pecht, No-fault-found and Intermittent Failures in Electronic Products, Microelectronics Reliability, Vol. 48, Issue 5, pp. 663-674, May 2008.
37. S. Han, S. Meschter, M. Osterman, and M. Pecht, Evaluation of Effectiveness of Conformal Coatings as Tin Whisker Mitigation, Journal of Electronic Materials, 6 July, 2012.
38. S. Mathew, W. Wang, M. Osterman and M. Pecht, Assessment of Solder Dipping as a Tin Whisker Mitigation Strategy, IEEE Trans. on Components, Packaging and Manufacturing Technology, Vol. 1, No. 6, pp. 957-963, June 2011.
39. S. Han, M. Osterman, and M. Pecht, Electrical Shorting Propensity of Tin Whiskers, IEEE Transactions on Electronics Packaging Manufacturing, Vol. 33, No. 3, July 2010.
40. T. Shibutani, Q. Yu, and M. G. Pecht, Tin Whisker Reliability in Microelectronics, Micromaterials and Nanomaterials, No. 9, pp. 49-53, 2009.
41. T. Shibutani, M. Osterman, and M. Pecht, Standards for tin whisker test methods on lead-free components, IEEE Transactions on Components and Packaging Technologies, Vol. 32, No. 1, pp. 216-219, March 2009.
42. Y. Chen, Q. Miao, B. Zheng, S. Wu, and M. Pecht, Quantitative Analysis of Lithium-Ion Battery Capacity Prediction via Adaptive Bathtub-Shaped Function, Energies, Vol. 6, No. 6, pp. 3082-3096, 2013.
43. P. Quintero and P. McCluskey, Temperature Cycling Reliability of High-Temperature Lead-Free Die-Attach Technologies, IEEE Transactions on Device and Materials Reliability, Vol.11, No.4, pp. 531-539, December 2011.
44. P. Quintero, P. McCluskey, and B. Koene, Thermomechanical reliability of a silver nano-colloid die attach for high temperature applications, Microelectronics Reliability, Vol. 54, No. 1, pp. 220-225, January 2014.
45. V. Khuu, M. Osterman, A. Bar-Cohen, and M. Pecht, Effects of Temperature Cycling and Elevated Temperature/Humidity on the Thermal Performance of Thermal Interface Materials, IEEE Transactions on Device and Materials Reliability, Vol. 9, No. 3, pp. 379-391,September 2009.
46. F. Chai, M. Osterman, and M. Pecht, Strain Range Based Solder Life Predictions under Temperature Cycling with Varying Amplitude and Mean, IEEE Transactions on Device and Materials Reliability, 2013.
47. R. Bakhshi, S. Kunche, and M. Pecht, Intermittent Failures in Hardware and Software, Journal of Electronic Packaging, Vol. 136, No. 1, March 2014.
48. J. Fan, K. Yung, and M. Pecht, Physics-of-Failure-Based Prognostics and Health Management for High-Power White Light-Emitting Diode Lighting, IEEE Transactions on Device and Materials Reliability, Vol. 11, No. 3, pp. 407-416, September 2011.
49. J. Fan, K. Yung and M. Pecht, Lifetime Estimation of High-Power White LED Using Degradation-Data-Driven Method, IEEE Transactions on Device and Materials Reliability, Vol. 12, No. 2, pp. 470-477, June 2012.
50. M.H. Chang, D. Das, P. Varde, and M. Pecht, Light Emitting Diodes Reliability Review, Microelectronics Reliability, Vol. 52, No. 5, pp. 762-782, May 2012.