I. Education

PhD (08/2003~06/2007)          Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore (Electronic Packaging Group)

MSc (09/2000~07/2002)           Tsinghua University,       P.R.China       Materials Science & Engineering

BSc (09/1995~07/2000)           Tsinghua University,       P.R.China      Materials Science & Engineering

BSc (09/1995~07/2000)           Tsinghua University,       P.R.China      Environmental Engineering

BA Econ (09/1998~07/2000)    Tsinghua University,       P.R.China      Business (Minor)

II. Professional Experience

     Expert knowledge in electromigration study on wafer level/package level Pb-free solder joints.

     Board level drop reliability studies, FPBGA assembly at different surface finish OSP, ENIG, Im-Sn, Im-Ag.

     Systematic research experience on Pb-free metallurgy for electronic packaging

     Through Si Vias(TSV)  in 3-D stacking packaging

     Nano crystalline and nano-twin in TSV electroplated copper

◆  Ph. D. Dissertation

Title: "Studies of interconnect failure in lead-free soldered assembly"

 Advisor:  Prof. John H.L. Pang, NTU

- Investigation of failure of fine pitch BGA solder joint subject to combined electrical, mechanical and thermal loadings, e.g. sequential thermal cycling followed by drop impact test

- the interfacial reaction between lead-free (SnAg, SnAgCu) and different PCB surface finish materials (Im-Sn, ENIG and Cu-OSP).

- Analysis of board level drop impact failure for FPBGA assembly at different surface finish.

- The project is supported by UTAC to choose the proper solder joint and substrates.

◆  MSc (09/200007/2002) Thesis

“Surface characterization and performance of Rare earth catalyst compound"

Advisor: Prof. Duan Weng, Asst. Prof. Xiaodong Wu, Prof. Hengde Li

- Development of wet surface coating technique to achieve high surface area

- Characterization of Nano-scale multilayered film prepared by ion beam deposition

- This project is supported by ISUZU, Japan.

III. Experienced Technical Skills

1. Plating and Packaging Reliability Studies

Electroless and electrolytic plating process; Intermetallic composition, morphology and growth characterization; Industrial solder reflow process

Electromigration Study in solder joint and copper via; Thermal Cycling and Thermal Shock Test; Drop Reliability; R.F. magnetron sputtering equipment

2. Characterization Technique

Dye Penetration: Characterization of electronic packaging failure.

Nanoindentation: Trained professional user of MTS Indentation CSM. Used for modulus measurement, creep analysis, pop-in effect analysis

DISC: Digital Image Speckle Correlation, used for in-situ strain and stress analysis

    Infrared Thermal Imaging System, non-contact temperature measurement

TEM: Transmission Electron Microscopy

AFM: Atomic Force Microscope

SEM: Scanning Electron Microscopy, professional user of JOEL SEM

XRD: X-ray Diffraction,  quantitative analysis and texture analysis

EDX: Energy Dispersive X-ray Analysis

IV. Work experience and Internship

    Postdoctoral Scholar (09/2007-), UCLA.

    Research Associate and Staff (12/2006-08/2007), Nanyang Technological University

    Research Associate (07/2002-07/2003), Tsinghua University

Research attachment in SIMTech, (Singapore Institute of Manufactory Technology) (08/2003~08/2006)

Exchange research student at Nagaoka University of Technology, Japan. Motoh's Research Group (10/2004)

V. Awards

02/2007: "National Award for the best research students studying oversea", Prize of US$5000, Ministry of Education, China.

05/2006: Best Paper award as one of the 7 finalists for Motorola/IEEE CPMT fellowship at 56^th ECTC, USA

08/2003-08/2006: Three Years Full PhD scholarship from Singapore Government

08/2000-08/2002: Graduate student scholarship, first class, Tsinghua University

1996-2000: Four-time undergraduate student awards, Tsinghua University

VI. Journal Paper Publications

2008

[1]  Luhua Xu, JK Han, Jarrett Liang and K.N. Tu; Yi-Shao Lai ELECTROMIGRATION INDUCED HIGH FRACTION OF COMPOUND FORMATION IN SNAGCU FLIP CHIP Applied Physics Letters, July 2008

[2]  Luhua Xu, John H. L. Pang, Faxing Che. Impact of Thermal Cycling on SAC Solder Joints and Board Level Drop Reliability?Journal of Electronic Materials, p880-886 June, 2008

[3]  Chong, D.Y.R.; Che, F.X.; Pang, J.H.L.; Luhua Xu; Xiong, B.S.; Toh, H.J.; Lim, B.K. . Evaluation on Influencing Factors of Board-Level Drop Reliability for Chip Scale Packages (Fine-Pitch Ball Grid Array) , IEEE Transactions on Advanced Packaging, p66-75 v31, 2008

2007

[1]  Luhua Xu, Pradeep Dixit, Jianmin Miao and John H.L. Pang; Xi Zhang and K.N. Tu; Robert Preisser Through-wafer electroplated copper interconnect with ultra-fine grains and high density of nano-twins, Applied Physics Letters, 90, 033111 2007

[2]  Pradeep Dixit, Luhua Xu, Jianmin Miao,  John H L Pang and Robert Preisser. Mechanical and microstructural characterization of high aspect ratio through-wafer electroplated copper interconnects,  Journal of Micromechanics and Microengineering, 17 2007:1749-1757

[3]  Pradeep Dixit, Tan Chee Wee, Luhua Xu, Nay Lin, Jianmin Miao, John H.L. Pang, Robert Preisser, "Fabrication and Characterization of Fine Pitch On-Chip Copper Interconnects for Advanced Wafer Level Packaging by High Aspect Ratio Through AZ9260 Resist Electroplating ", Journal of Micromechanics and Microengineering, 17 2007:1078-1086

2006

[1]  Luhua Xu, John H.L. Pang and K.N. Tu, Effect of electromigration-induced back stress gradient on nano-indentation marker movement in SnAgCu solder joints, Applied Physics Letters, 89, 221909, 2006

[2]  Fei Ren, Jae-Woong Nah, K. N. Tu Bingshou Xiong, Luhua Xu, and John H. L. Pang Electromigration induced ductile-to-brittle transition in lead-free solder joints Applied Physics Letters 89, 141914 ,2006

[3]  Luhua Xu and John H.L. Pang, In-Situ Electromigration Studies on SnAgCu Solder Joint by Digital Image Speckle Analysis, Journal of Electronic Materials, 2006 (35-11):1993-1999

[4]  Luhua Xu, John H. L. Pang, Fei Ren, K. N. Tu. “Electromigration Effect on Intermetallic Growth and Young's Modulus in SAC/ENIG Solder Joint?Journal of Electronic Materials, 2006 (35-12):2116-2125

[5]  Luhua Xu, John H. L. Pang, “Nanoindentation on SnAgCu and SnCu Lead-Free Solder and Analysis? Journal of Electronic Materials, 2006 (35-12):2107-2116

[6]  Luhua Xu, John H.L. Pang. “Nano-Indentation Characterization of Lead-Free Solder and IMC layer Properties? Thin Solid Films. 504, 362, 2006. 

2005-2004

[1]  Luhua Xu, John H. L. Pang, Kithva H. Prakash. “Isothermal and Thermal Cycling Aging On IMC Growth Rate in Lead-Free and Lead-Based Solder Interface? IEEE Transactions, Components and Packaging Technologies 2005(28):408 

[2]  John H. L. Pang, T. H. Low, B. S. Xiong, Luhua Xu. “Thermal cycling aging effects on Sn–Ag–Cu solder joint microstructure, IMC and strength? Thin Solid Films, Vol462-463, 2004, pp370-375

[3]  John.H.L Pang, Luhua Xu. “Intermetallic Growth Studies on Sn-Ag-Cu Lead-Free Solder Joints? Journal of Electronic Materials, 2004 (33-10): pp1219-1226

2004 and before

[1]  Xiaodong Wu, Luhua Xu, Duan Weng. The NO selective reduction on the La1-xSrxMnO3 catalysts. Catalysis Today, Vol 90 3-4, 2004: 199-206

[2]  Xiaodong Wu, Luhua Xu, Bin Yang, Duan Weng. Surface characterization and catalytic performance of La0.7Sr0.3MnO3+r coating deposited by plasma spraying. Surface & Coating Technology. Vol 184-1, 2004,pp40-46

[3]  Xiaodong Wu, Luhua Xu, Duan Weng. The thermal stability and catalytic performance of Ce-Zr promoted Rh-Pd/g-Al2O3 automotive catalysts. Applied Surface Science 2004, 221(1-4):375-383

[4]  Jizhong Zhang, Luhua Xu. Influence of aging on the morphology and wettability of polytetrafluoroethylene implanted by high-fluence carbon ion. Materials Letters 2002(56): 410?17

VII. IEEE Collections of Conference Proceedings

[1] Combined Thermal and Electromigration Exposure Effect on SnAgCu BGA Solder Joint Reliability
Luhua Xu; Pang, J.H.L.;
Electronic Components and Technology Conference, 2006. Proceedings. 56th
30 May-2 June 2006 Page(s):1154 - 1159
Digital Object Identifier 10.1109/ECTC.2006.1645799
 

[2] Effect of Intermetallic and Kirkendall Voids Growth on Board Level Drop Reliability for SnAgCu Lead-Free BGA Solder Joint
Luhua Xu; Pang, J.H.L.;
Electronic Components and Technology Conference, 2006. Proceedings. 56th
30 May-2 June 2006 Page(s):275 - 282
Digital Object Identifier 10.1109/ECTC.2006.1645659
 

[3] Intermetallic growth studies on SAC/ENIG and SAC/Cu-OSP lead-free solder joints
Luhua Xu; Pang, J.H.L.;
Thermal and Thermomechanical Phenomena in Electronics Systems, 2006. ITHERM '06. The Tenth Intersociety Conference on
30 May-2 June 2006 Page(s):6 pp.
Digital Object Identifier 10.1109/ITHERM.2006.1645472
 

[4] Lead free solder joint reliability characterization for PBGA, PQFP and TSSOP assemblies
Che, F.X.; Pang, J.H.L.; Xiong, B.S.; Luhua Xu; Low, T.H.;
Electronic Components and Technology Conference, 2005. Proceedings. 55th
31 May-3 June 2005 Page(s):916 - 921 Vol. 1
Digital Object Identifier 10.1109/ECTC.2005.1441381
 

[5] In-situ study of the effect of electromigration on strain evolution and mechanical property change in lead-free solder joints
Fei Ren; Luhua Xu; Xi Zhang; Jae-Woong Nah; Pang, J.H.L.; Tu, K.N.;
Electronic Components and Technology Conference, 2006. Proceedings. 56th
30 May-2 June 2006 Page(s):4 pp.
Digital Object Identifier 10.1109/ECTC.2006.1645800
 

[6] Intermetallic Growth and Failure Study for Sn­Ag­Cu/ENIG PBGA Solder Joints Subject to Thermal Cycling
Luhua Xu; Pang, J.H.L.; Che, F.X.;
Electronic Components and Technology Conference, 2005. Proceedings. 55th
31 May-3 June 2005 Page(s):682 - 686
Digital Object Identifier 10.1109/ECTC.2005.1441342
 

[7] Nanoindentation on SnAgCu lead-free solder and analysis
Luhua Xu; Pang, J.H.L.;
Electronic Packaging Technology Conference, 2005. EPTC 2005. Proceedings of 7th
Volume 1, 7-9 Dec. 2005 Page(s):4 pp.
Digital Object Identifier 10.1109/EPTC.2005.1614421
 

[8] Drop reliability performance assessment for PCB assemblies of chip scale packages (CSP)
Chong, D.Y.R.; Toh, H.J.; Lim, B.K.; Low, P.T.H.; Pang, J.H.L.; Che, F.X.; Xiong, B.S.; Luhua Xu;
Electronic Packaging Technology Conference, 2005. EPTC 2005. Proceedings of 7th
Volume 1, 7-9 Dec. 2005 Page(s):8 pp.
Digital Object Identifier 10.1109/EPTC.2005.1614404
 

[9] Failure study of Sn-Ag-Cu lead-free solder joint by digital image speckle analysis (DISA)
Luhua Xu; Pang, J.H.L.; Faxing Che;
Electronic Packaging Technology Conference, 2005. EPTC 2005. Proceedings of 7th
Volume 1, 7-9 Dec. 2005 Page(s):4 pp.
Digital Object Identifier 10.1109/EPTC.2005.1614379
 

[10] Interfacial IMC and Kirkendall void on SAC solder joints subject to thermal cycling
Luhua Xu; Pang, J.H.L.;
Electronic Packaging Technology Conference, 2005. EPTC 2005. Proceedings of 7th
Volume 2, 7-9 Dec. 2005 Page(s):5 pp.
Digital Object Identifier 10.1109/EPTC.2005.1614520
 

[11] Failure analysis of lead-free Sn-Ag-Cu solder joints for 316 I/O PBGA package
Luhua Xu; Pang, J.H.L.; Che Faxing;
Physical and Failure Analysis of Integrated Circuits, 2005. IPFA 2005. Proceedings of the 12th International Symposium on the
27 June-1 July 2005 Page(s):323 - 327
Digital Object Identifier 10.1109/IPFA.2005.1469188
 

[12] In-situ electromigration studies on Sn-Ag-Cu solder joint by digital image speckle analysis (DISA)
Luhua Xu; Pang, J.H.L.; Xiong, B.S.;
Electronics Packaging Technology Conference, 2004. EPTC 2004. Proceedings of 6th
2004 Page(s):410 - 413
Digital Object Identifier 10.1109/EPTC.2004.1396643
 

[13] Effect of electromigration on mechanical behavior of solder joints
Ren, F.; Nah, J.W.; Suh, J.O.; Tu, K.N.; Xiong, B.S.; Xu, L.H.; Pang, J.H.L.;
Advanced Packaging Materials: Processes, Properties and Interfaces, 2005. Proceedings. International Symposium on
16-18 March 2005 Page(s):66 - 69
Digital Object Identifier 10.1109/ISAPM.2005.1432048

[14] Performance Assessment on Board-level Drop Reliability for Chip Scale Packages (Fine-Pitch BGA)
Chong, D.Y.R.; Che, F.X.; Xu, L.H.; Toh, H.J.; Pang, J.H.L.; Xiong, B.S.; Lim, B.K.;
Electronic Components and Technology Conference, 2006. Proceedings. 56th
30 May-2 June 2006 Page(s):356 - 363
Digital Object Identifier 10.1109/ECTC.2006.1645671
 

[15] IMC consideration in FEA simulation for PB-free solder joint reliability
Fa-Xing Che; Pang, J.H.L.; Xu, L.H.;
Thermal and Thermomechanical Phenomena in Electronics Systems, 2006. ITHERM '06. The Tenth Intersociety Conference on
30 May-2 June 2006 Page(s):1018 - 1023
Digital Object Identifier 10.1109/ITHERM.2006.1645456
 

[16] Drop Impact Reliability Testing for Lead­Free and Leaded Soldered IC Packages
Chong, D.Y.R.; Kellin Ng; Tan, J.Y.N.; Low, P.T.H.; Pang, J.H.L.; Che, F.X.; Xiong, B.S.; Xu, L.H.;
Electronic Components and Technology Conference, 2005. Proceedings. 55th
31 May-3 June 2005 Page(s):622 - 629
Digital Object Identifier 10.1109/ECTC.2005.1441334