EPSI INC.  -  Electronics Packaging Solutions International Inc.
P.O. Box 1522, Montclair, NJ 07042 USA, tel. & fax: +1 (973)746-3796



  • Jean-Paul M. Clech (EPSI Inc.), Richard J. Coyle (Nokia Bell Labs), Babak Arfaei (Ford Motor Co.), "Pb-Free
    Solder Joint Thermo-Mechanical Modeling: State of the Art and Challenges", JOM (TMS), Advances in
    Electronic Interconnection Materials, January 2019, Volume 71, Issue 1, pp 143–157.  First Online: 17 August
    2018.  Available for download (Springer Pub.).



  • Clech, J-P., "A Pseudo-Stress. Pseudo-Strain Methodology to Predict Lead-Free Solder Joint
    Reliability", presented a SMTA International (SMTAI) Conference, Oct. 2013, Dallas, TX.  See
    presentation (.pdf file).  The full paper can be purchased, with the 2013 SMTAI Proceedings, from the SMTA
    bookstore at: http://www.smta.org/knowledge/proceedings.cfm .

  • Saito, T., Tamai, N. (Hirose Electric, Japan), Kikuchi, T. (Hirose Electric, USA), Ramakrishna, G. (Cisco
    Systems), Chu, Q., Sethuraman, S. (Jabil), Shea, C. (Shea Engineering Services) and Clech, J-P. (EPSI Inc.),
    "Long-Term Reliability Assessment Of A New Lead-Free Area Array Connector System", presented
    at SMTA International Conference (SMTAI 2010).  See abstract. The paper can be purchased, with the 2010
    SMTAI Proceedings, from the SMTA bookstore at:  http://www.smta.org/knowledge/proceedings.cfm .

  • Clech, J-P., Henshall, G. and Miremadi, J., "Closed-Form, Strain-Energy Based Acceleration Factors for
    Thermal Cycling of Lead-Free Assemblies", presented at SMTA International Conference (SMTAI 2009),
    Oct. 4-8, 2009, San Diego, CA. See abstract and presentation (.pdf file).  Note: paper received BEST OF
    PROCEEDINGS AWARD.  The paper can be purchased, with the 2009 SMTAI Proceedings, from the
    SMTA bookstore at:  http://www.smta.org/store/book_detail.cfm?book_id=358 .  

  • Clech, J-P., "Lead-free Solder Joint Reliability", Chapter 6, in book: Lead Free Soldering, ed. Jasbir Bath
    (Solectron), Springer Publications, Spring 2007.

  • Clech, J-P., "Review And Analysis Of Lead-Free Solder Material Properties", Chapter 2 Lead-Free
    Electronics: iNEMI Projects Lead to Successful Manufacturing. ed.: Bath, J., Handwerker, C., Bradley,
    E. and Parker, R., IEEE Press / Wiley, October 2007.

  • Zhang, R. and Clech, J-P., "Applicability of various Pb-free solder joint acceleration factors", Proceedings
    (CD-ROM), Lead-free Symposium, Surface Mount International Conference, SMTAI '06, September 2006,
    Chicago, IL (presented by Ron Zhang, Sun Microsystems).  See presentation (.pdf file) and paper (.pdf).


  • Clech, J-P.,  "Acceleration factors and thermal cycling test efficiency for lead-free Sn-Ag-Cu assemblies",
    Proceedings, SMTA International Conference, Chicago, IL, Sept. 25-29, 2005, pp. 902-917.  Download
    SMTAI'05 Paper , Presentation (.pdf files).

  • "Reliability evaluation of lead-free SnAgCu PBGA676 components using tin-lead and lead-free SnAgCu
    solder paste", Jasbir Bath, Sundar Sethuraman, Xiang Zhou, Dennis Willie, Kim Hyland, Solectron
    Corporation; Keith Newman, Livia Hu, Dave Love, Heidi Reynolds, Ken Kochi, Sun Microsystems; Diana
    Chiang, Vicki Chin, Sue Teng, Mudasir Ahmed, Cisco Systems; Greg Henshall, Valeska Schroeder, Hewlett
    Packard, Quang Nguyen, Abhay Maheswari, MJ Lee, Xilinx Corporation; Jean-Paul Clech, EPSI Inc., Jeff
    Cannis, Amkor Technologies, John Lau, Agilent Technologies, Chris Gibson, Motorola Inc., Proceedings,
    SMTA International Conference, Chicago, IL, Sept. 25-29, 2005, pp. 891-917.   Paper can be purchased
    from the SMTA's Publications Dept.

  • Clech, J-P.,  "An Extension of the Omega Method to  Primary and Tertiary Creep of Lead-Free Solders",
    Proceedings, 55th Electronic Components and Technology Conference, ECTC'05, Orlando, FL, May 31-
    June 3, 2005, pp. 1261-1271.  Download: ECTC Paper , Presentation  (.pdf files).

  • "Overview of Lead Free SAC Alloys Evaluation and Reliability Test Program", Karl Seelig, AIM Inc ; Bernard
    Tournier, Avantec; Paul Lotosky, Cookson Electronic Assembly Material; John Vivari, EFD Inc; Jim Slattery,
    Indium Corporation; Tony Hilvers, IPC; Greg Munie, Kester Solder; Tippy Wicker, Qualitek International Inc;
    Dongkai Shangguan, Flextronics, Jasbir Bath, Solectron; George Wenger, Andrew Corporation; Jean-Paul
    Clech, EPSI; Dean May, NavSea Crane, Proceedings, IPC/Soldertec Global 3rd International Conference on
    Lead Free Electronics, June 7-10, 2005, Barcelona, Spain.  Paper / CD-ROM proceedings can be purchased
    through the IPC's Publication Dept.

  • Clech, J-P., "An obstacle-controlled creep model for Sn-Pb and Sn-based lead-free solders", Proceedings,
    SMTA International Conference, Chicago, IL, September 26-28, 2004.  Download SMTAI'04 paper ,
    Presentation .

  • Clech, J-P., "Comparative analysis of creep data for Sn-Ag-Cu solder joints in shear", in Micromaterials and
    Nanomaterials (IZM / MMCB publication, Fraunhofer Institute, Berlin, Germany), Issue 3 (dedicated to the
    memory of Dr. Andreas Schubert), 2004, pp. 144-155.  Download Micromaterials & Nanomaterials 2004
    paper  (2.98 Mbytes, .pdf file).

  • Clech, J-P., "Lead-free and mixed assembly solder joint reliability trends", in Proceedings (CD-ROM), IPC /
    SMEMA Council APEX 2004 Conference, Anaheim, CA, Feb. 23-26, 2004, pp. S28-3-1 through S28-3-
    14.  Download: APEX 2004 Paper  (825 kbytes .pdf file); APEX 2004 Presentation (238 kbytes PowerPoint
    file).   Slides # 8 and # 9 show comparisons of SnPb and lead-free isothermal creep rate data at temperatures
    from -55C to 125C.  Figures shows the cross-over point of SnPb and lead-free creep curves for common
    lead-free alloys.

  • Clech, J-P., “Review and analysis of lead-free solder material properties”, chapter in IEEE/Wiley book on
    NEMI’s Lead-Free Project, 2004 - study sponsored by US National Institute of Standards and Technology

Clech, J-P., "Solder joint reliability of CSP versus BGA assemblies" (invited paper), Proceedings, System Integration in Micro Electronics, SMT
ESS & Hybrids Conference, Nuremberg, Germany, June 27-29, 2000, pp. 19-28.
 Download Nuremberg 2000 paper (73kB .pdf file) .

NOTE: recommended reading for users of the Solder Reliability Solutions (SRS) software.

  • Paper shows additional validation of the SRS model against accelerated thermal cycling test results for fip-chip, CSP and
    cavity-down BGA assemblies.
  • New flip chip reliability test results are used to test and validate the use if "solder volume correction factors" for small size
    solder joints (as described in SMI'98 paper below).

Clech, J-P., "BGA, Flip-Chip and CSP solder joint reliability" (invited paper), Proceedings, MicroMat2000 Conference, Berlin, Germany, April
2000, pp. 153-158.

Reichelt, G. and Clech, J-P., "Life expectancy of solder joints SMD-PCB: comparing test data to an improved life prediction equation",
Nepcon West '99, Anaheim, CA, February 21-25, 1999, Vol. III, pp. 1269-1285.

Clech, J-P., "Flip-chip / CSP assembly reliability and solder volume effects", Proceedings, Surface Mount International Conference, San Jose, CA,
August 25-27, 1998, pp. 315-324.  
Download SMI'98 paper (119kB .pdf file) .

NOTE: recommended reading for users of the Solder Reliability Solutions (SRS) software.

 Paper shows the validation of the SRS model against accelerated thermal cycling test results for flip-chip, microBGA and
ceramic CSP assemblies.

 Includes a new correlation of fatigue data with an empirical "solder volume correction factor" for small size solder joints
(flip-chip, CSP assemblies).  Model calibration factors to account for solder volume effects are defined in page 5 of this paper.  

Clech, J-P., "Flip-chip and chip-scale package reliability modeling", Chip Scale Review, Vol. 2, No. 5, November 1998, pp. 49-54 (out-of-print, no .
pdf file available).

Jean-Paul Clech and Joseph Fjelstad, "Reliability prediction of area-array CSPs", Electronic Packaging and Production, June 1997, pp. 91-96 (out-
of-print, no .pdf file available).

J-P. Clech, "SMT/CSP reliability perspectives", SMTA Newsletter, April 1997, p. 3.
Download SMTA Newsletter Article (8kB .pdf file).

J-P. Clech, "Tools to assess the attachment reliability of modern soldered assemblies (BGA, CSP...)", Proceedings, Nepcon West’97, Anaheim, CA,
February 23-24, 1997, Vol. I, pp. 35-45.  
Download Nepcon West '97 paper (100kB .pdf file) .

NOTE: recommended reading for users of the Solder Reliability Solutions (SRS) software.  Includes description of procedure to
effective CTE of perimeter PBGA package.

J-P.Clech, "Reliability challenges and modeling of miniaturized soldered assemblies" (invited paper), Proceedings, TMS’97, The Minerals, Metals
Materials Society, Symposium on "Design and Reliability of Solders and Solder Interconnections", Orlando, FL., February 9-13, 1997, pp. 367-
Download TMS'97 paper (130kB .pdf file) .

NOTE: recommended reading for users of the Solder Reliability Solutions (SRS) software.  Includes details of underfill flip-chip
model in appendix.

J-P. Clech, "Solder Reliability Solutions: a PC-based design-for-reliability tool", Proceedings, Surface Mount International Conference, Sept. 8-12,
1996, San Jose, CA, pp. 136-151. Republished in
Soldering and Surface Mount Technology, Wela Publications, British Isles, Vol. 9, No. 2, July
1997, pp. 45-54.
Download SMI'96 paper (162kB .pdf file) .

NOTE: recommended reading for users of the Solder Reliability Solutions (SRS) software.

 Paper gives basic description of SRS model, including validation across a database of thirty accelerated tests.

 Defines model terminology and software input, output parameters.

J-P. Clech, "Strength and reliability of flip chip assemblies with underfill", EPSI Inc. Technical Publication, 1996 (available to licensed users of the
upon request).

J-P. Clech, "Solder reliability solutions: from LCCCs to area array assemblies", Proceedings, Nepcon West '96, Anaheim, CA, February 25-29,
1996, pp. 1665-1680.
 Download Nepcon West '96 paper (103kB .pdf file) .

NOTE: recommended reading for users of the Solder Reliability Solutions (SRS) software.

 Paper gives a general description of the SRS model, including validation of the model against test results for full-array
PBGA assemblies (with substrate thickness and pad size effects).

OTHER PUBLICATIONS (with AT&T Bell Laboratories colleagues):

Ejim, T. I. and Clech, J-P., "Moiré analysis and modeling of area array assemblies", Proceedings, VIII International Congress on Experimental and
Applied Mechanics, Nashville, TN, June 10-12, 1996, pp. 53-54. Full paper in post-conference proceedings, Society for Experimental Mechanics,
Bethel, CT, 1996.

Ejim, T. I., Clech, J-P., Dudderar, T. D., Guo, Y. and Han, B., “Measurement of thermomechanical deformations of plastic ball grid array
assemblies using moiré interferometry”, Proceedings, 1995 SEM Spring Conference and Exhibit, June 12-14, 1995, Grand Rapids, Michigan, pp.

Clech, J. P., Noctor, D. M., Manock, Lynott, G. W. and Bader, F. E., “Surface mount failure statistics and failure free time”, Proceedings, 44th
Washington, DC, May 1-4, 1994, pp. 487-497.  
Download ECTC'94 paper (186kB .pdf file) .

Note: recommended reading if you are interested in the application of Three-Parameter (3P) Weibull distributions to the statistical analysis of
solder joint failure times.

Clech, J-P., Manock, J. C., Noctor, D. M., Bader, F. E. and Augis, J. A., "A Comprehensive Surface Mount Reliability model: background,
validation and applications", Proceedings Surface Mount International ‘93, San Jose, CA, August 29-September 2, 1993, Vol. I, pp. 363-375.  
Download SMI'93 paper (86kB .pdf file) .  

Noctor, D. and Clech, J-P., “Accelerated testing and predictive modeling of the attachment reliability of alloy 42 and copper leaded TSOPs”,
Proceedings, Nepcon East, Boston, MA, June 14-17, 1993, pp. 193-206.
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