Publications affiliated with UCLA (K. N. Tu)

1. H. K. Kim, H. K. Liou, and K. N. Tu, "Morphology of instability of wetting tips of eutectic SnBi , eutectic SnPb, and pure Sn on Cu," J. of Materials Research, 10. 497-504 (1995).

2. Y. Wang, H. K. Kim, H. K. Liou, and K. N. Tu, "Rapid soldering reactions of eutectic SnBi and eutectic SnPb solder on Pd surfaces," Scripta Metall. And Mater., 32, 2087-2092 (1995).

3. H. K. Liou, J. S. Huang, and K. N. Tu, "Oxidation of Cu and Cu3Ge thin films," J. Appl. Phys., 77, 5443-5445 (1995).

4. L. T. Shi, and K. N. Tu, "Finite element stress analysis of failure mechanism in a multi-level metallization structure," J. Appl. Phys., 77, 3037-3041 (1995).

5. H. K. Kim, H. K. Liou, and K. N. Tu, "Three-dimension morphology of a very rough interface formed in the soldering reaction between eutectic SnPb and Cu," Appl. Phys. Lett., 66, 2337-2339 (1995).

6. F. G. Si and K. N. Tu, "Entropic origin of the free energy in nucleation of crystallites in amorphous CoSi2 thin films," Phys. Rev. Lett., 74, 4476-4478 (1995).

7. K. L. Lee, C. K. Hu, and K. N. Tu, "In-situ SEM comparison studies on electromigration of Cu and Cu(Sn) alloy for advanced chip interconnects," J. Appl. Phys., 78, 4428-4437 (1995).

8. Y. Wang and K. N. Tu, "Ultra-fast intermetallic compound formation between eutectic SnPb and Pd where the intermetallic is not a diffusion barrier," Appl. Phys. Lett., 67, 1069-071 (1995).

9. H. K. Kim and K. N. Tu, "Rate of consumption of Cu soldering accompanied by ripening," Appl. Phys. Lett., 67, 2002-2004 (1995).

10. H. K. Kim and K. N. Tu, "Kinetic analysis of the soldering reaction between eutectic SnPb alloy and Cu accompanied by ripening, " Phys. Rev. B53, 16027- 16034 (1996)

11. Ann A. Liu, H. K. Kim, K. N. Tu, and P. A. Totta, "Spalling of Cu6Sn5 spheroids in the soldering reaction of eutectic SnPb on Cr/Cu/Au thin films," J. Appl. Phys., 80, 2774-2780 (1996).

12. K. N. Tu, "Cu/Sn interdiffusion reactions: thin film case vs bulk case," Materials Chemistry and Physics, 46, 217-223 (1996).

13. H. K. Kim, K. N. Tu, and P. A. Totta, "Ripening-assisted asymmetric spalling of Cu-Sn compound spheroids in solder joints on Si wafers," Appl. Phys. Lett. 68, 2204-2206 (1996).

14. P. G. Kim and K. N. Tu, "Morphology of wetting reaction of eutectic SnPb solder on Au foils," J. Appl. Phys., 80, 3822-3827 (1996).

15. C. Y. Liu, K. H. Kim, K. N. Tu, and P. A. Totta, "Dewetting of molten Sn on Au/Cu/Cr thin film metallization," Appl. Phys. Lett., 69, 4014-4016 (1996).

16. J. S. Huang, H. K. Liou, and K. N. Tu, "Polarity effect of electromigration in Ni2Si contacts on Si," Phys. Rev. Lett., 76, 2346-2349 (1996).

17. J. S. Huang and K. N. Tu, "Novel dopant activation of heavily-doped p+-Si by high current density," Phys. Rev. Lett., 77, 4926-4929 (1996).

18. C. C. Lin, W.S. Chen, H. L. Hwang, K. Y. J. Hsu, H. K. Liou and K. N. Tu, "Reliability study of submicron Ti silicide contacts," Appl. Surface Science, 92, 660-664 (1996).

19. T. Laursen, D. Adams, T. L. Alford, K. N. Tu, F. Deng, R. Morton, and S. S. Lau, "Encapsulation of Ag films in Ag-Ti alloy bilayer structures," Thin Solid Films, 290-291, 411-416 (1996).

20. G. Z. Pan, K. N. Tu, and S. Prussin, "Size-distribution of end-of-range dislocation loops in Si-implanted Si," Appl. Phys. Lett., 68, 1654-1656 (1996).

21. Chih Chen, G. Z. Pan, and K. N. Tu, "Preparation of twist-type bicrystals of Si," Materials Chemistry and Physics, 47, 90-92 (1997).

22. J. S. Huang, J. Zhang, A. Cruves, and K. N. Tu, "Grain growth in bulk Cu and Cu(Sn) alloys," Materials Chemistry and Physics, 49, 33-41 (1997).

23. G. Z. Pan, K. N. Tu, and S. Prussin, "Size distribution and annealing behavior of end-of -range dislocation loops in Si-implanted Si," J. Appl. Phys. 81, 78-84 (1997).

24. P. G. Kim, K. N. Tu, and D. C. Abbott, "Effect of Pd thickness on soldering reaction between eutectic SnPb and plated Pd/Ni thin films on Cu leadframe," Appl. Phys. Lett. 71, 61-63 (1997).

25. G. Z. Pan, Ann A. Liu, H, K, Kim, K. N. Tu, and P. A. Totta, "Microstructure of phased-in Cr-Cu/Cu/Au bump-limiting-metallization and its soldering behavior with high Pb and eutectic SnPb solders," Appl. Phys. Lett., 71, 2946-2948 (1997).

26. G. Z. Pan, K. N. Tu, and S. Prussin, "Microstructural evolution of (113) rodlike defects and (111) dislocation loops in Si-implanted Si," Appl. Phys. Lett., 71, 659- 601 (1997).

27. G. Z. Pan and K. N. Tu, "Transmission electron microscopy on (113) rodlike defects and (111) dislocation loops in silicon-implanted silicon," J. Appl. Phys. 82, 601-608 (1997).

28. J. S. Huang, S. S. Huang, K. N. Tu, F. Deng, S. S. Lau, S. L. Cheng and L. J. Chen, "Kinetics of Cu3Ge formation and reaction with Al," J. Appl. Phys., 82, 644-649 (1997).

29. J. S. Huang, K. N. Tu, S. W. Bedell, W. A. Lanford, S. L. Cheng, J. B. Lai, and L. J. Chen, "Polarity effect on failure of Ni and Ni2Si contacts on Si, " J. Appl. Phys., 82, 2370-2377 (1997).

30. C. Y. Liu, and K. N. Tu, "Morphology of wetting reactions of SnPb alloys on Cu as a function of alloy composition," J. Materials Research, 13, 37-44 (1998).

31. P. G. Kim and K. N. Tu, "Fast dissolution and soldering reactions on Au foils," Materials Chemistry & Physics, 53/2, 165-171 (1998)

32. D. W. Zheng, Weijia Wen, and K. N. Tu, "Reactive wetting and dewetting induced diffusion-limited aggregation," Phys. Rev. E57, R3719-R3722 (1998).

33. D. W. Zheng, Z. Y. Jia, C. Y. Liu, Weijia Wen, and K. N. Tu, "Size dependent dewetting and sideband reaction of eutectic SnPb on Au/Cu/Cr thin film," J. Materials Research 13, 1103-1106 (1998).

34. Weijia Wen, D. W. Zheng, and K. N. Tu, "In-situ time response measurement of the microspheres dispersed in electrorheological fluids, " Phys. Rev. E57, 4516- 4519 (1998).

35. J. S. Huang, C. N. Liao, K. N. Tu, S. L. Cheng and L. J. Chen, "Abnormal electrical behavior and phase changes in implanted p+ and n+ -Si channels under high current densities," J. Appl. Phys. 84, 4788-4796 (1998).

36. P. G. Kim, K. N. Tu, and D. C. Abbott, "Time and temperature dependent wetting behavior of eutectic SnPb on Cu lead-frame plated with Pd/Ni and Au/Pd/Ni thin films," J. Appl. Phys. 84, 770-775 (1998).

37. C. Y. Liu, and K. N. Tu, "Reactive flow of molten Pb(Sn) alloys in Si grooves coated with Cu film," Phys. Rev. E58, 6308-6311 (1998).

38. L. A. Chow, Y. H. Xu, B. Dunn, K. N. Tu, and C. Chiang, "Cracking behavior of xerogel silica films on silicon substrates," Appl. Phys. Lett. 73, 2944-2946 (1998).

39. Weijia Wen, D. W. Zheng, K. N. Tu, "Fractal or Chain? Which is the preferred spatial configuration in field-induced solid particle/liquid phase separation?" Phys. Rev. E58, 7682-7685 (1998).

40. Weijia Wen, D. W. Zheng, and K. N. Tu, "Experimental investigation for the time- dependent effect in electrorheological fluids under time-regulated high pulse electric field," Review of Scientific Instruments, 69, 3573-3576 (1998).

41. Weijia Wen, F. Kun, K. F. Pal, D. W. Zheng, and K. N. Tu, "Aggregation kinetics and stability of structures formed by magnetic microspheres," Phys. Rev. E59, R4758-R4761, (1999).

42. Weijia Wen, Ning Wang, D. W. Zheng, and K. N. Tu, "Two and three-dimensional matrixes formed by magnetic microspheres," J. Materials Research, 14, 1186-1189 (1999).

43. D. W. Zheng, Weijia Wen, K. N. Tu, and P. A. Totta, "In-situ scanning electron microscopy study of eutectic SnPb and pure Sn wetting on Au/Cu/Cr multi-layered thin films, " J. Materials Research, 14, 745-749 (1999).

44. C. Y. Liu, Chih Chen, K. Mal, and K. N. Tu, "Direct correlation of mechanical failure and metallurgical reaction in flip chip solder joints," J. Appl. Phys. 85, 3882-3886 (1999).

45. Weijia Wen, D. W. Zheng, and K. N. Tu, "Chain/column evolution and corresponding electrorheological effect," J. Appl. Phys. 85, 530-533 (1999).

46. J. W. Jang, P. G. Kim, K. N. Tu, D. Frear, and P. Thompson, "Solder reaction- assisted crystallization of electroless Ni (P) under-bump metallization in low cost flip chip technology," J. Appl. Phys. 85, 8456-8463 (1999).

47. P. G. Kim, J. W. Jang, K. N. Tu, and D. Frear, "Kinetic analysis of interfacial penetration accompanied by intermetallic compound formation," J. Appl. Phys. 86, 1266-1272 (1999).

48. C. Y. Liu, Chih Chen, C. N. Liao, and K. N. Tu, "Microstructure-electromigration correlation in a thin stripe of eutectic SnPb solder stressed between Cu electrodes," Appl. Phys. Lett., 75, 58-60, 1999.

49. Yuhuan Xu, Yi-pin Tsai, K. N. Tu, Bin Zhao, Q. Z. Liu, Maureen Brongo, George T. T. Sheng, and C. H. Tung, "Dielectric property and microstructure of a porous polymer materials with ultra-low dielectric constant," Appl. Phys. Lett. 75, 853-855 (1999).

50. Chih Chen, J. S. Huang, C. N. Liao and K. N. Tu, "Dopant activation of heavily doped SOI by high density currents," J. Appl. Phys., 86, 1552-1557 (1999)..

51. Chih Chen, K. N. Tu, C. H. Tung, T. T. Sheng, A. Ploessl, R. Scholz, and U. Goesele, " Twist-type Si bicrystals and compliant substrates prepared from SOI wafers," Phil. Mag. A80, 881-891 (2000).

52. J. W. Jang, P. G. Kim, K. N. Tu, and M. Lee, "High temperature Pb-free SnSb solders: wetting and interfacial reactions on Cu foils and phased-in Cu-Cr thin films", J. Materials Research, 14, 3895-3900 (1999).

53. Weijia Wen, D. W. Zheng, and K. N. Tu, "Field induced coarsening of electrorheological suspensions," App. Phys. Lett. (submitted).

54. C. N. Liao, Chih Chen and K. N. Tu, "Thermoelectric properties of silicon thin film in SOI," J. Appl. Phys.86, 3204-3208 (1999).

55. L. A. Chow, B. Dunn, K. N. Tu, and C. Chiang, "The mechanical properties of xerogel silica films derived from stress versus temperature and cracking experiements," J. Appl. Phys., 87, 7788-7792 (2000).

56. D. W. Zheng, Xinhua Wang, K. K. Shyu, C. T. Chang, Y. Guo, V. Sarihari, Weijia Wen, and K. N. Tu, "A study of local stress using stress-absorbing Si diaphragm," J. Vac. Sci. Tech. B 17(5), 2178-2181(1999).

57. J. R. LaGraff, G. Z. Pan, and K. N. Tu, "Si ion implantation of STO passivated YBCO films for multi-layer processing," Applied Phys. (submitted).

58. A. S. Zuruzi, C. H. Chiu, W. T. Chen, S. K. Lahiri, and K. N. Tu, "Interdiffusion of high Sn and high lead (PbSn) solders in low temperature flip chip joints during reflow," Appl. Phys. Lett. 75, 3635-3637 (1999).

59. A. S. Zuruzi, C. H. Chiu, S. K. Lahiri, and K. N. Tu, "Roughness evolution of Cu6Sn5 intermetallic during soldering and its effect on wettability," J. Appl. Phys. 86, 4916-4921 (1999).

60. J. W. Jang, C. Y. Liu, P. G. Kim, K. N. Tu, A. K. Mal, and D. R. Frear, "Interfacial morphology and shear deformation of flip chip solder joints," J. Appl. Phys. (to be submitted).

61. C. Y. Liu, K. N. Tu, T. T. Sheng, C. H. Tung, D. R. Frear, and P. Elenius, "Electron microscopy study of interfacial reaction between eutectic SnPb and Cu/Ni(V)/Al thin film metallization," J. Appl. Phys. 87, 750-754 (2000).

62. P. G. Kim, J. W. Jang, T. Y. Lee, and K. N. Tu, "Interfacial reaction and wetting behavior in eutectic SnPb solder on Ni/Ti thin films and Ni foils," J. Appl. Phys. 86, 6746-6751 (1999).

63. C. N. Liao, C. Chen, J. S. Huang, and K. N. Tu, "Asymmetrical heating behavior of doped Si channels in bulk Si and in SOI under high current density," J. Appl. Phys. 86, 6895-6901 (1999).

64. F. Kun, K. F. Pal, W. Wen, and K. N. Tu, " Break-up of dipolar rings under an external magnetic field," Phys. Rev. Lett., 277, 287-293(2000).

65. K. N. Chen, H. H. Lin, S. L. Cheng, Y. C. Peng, G. H. Shen, L. J. Chen, C. R. Chen, J. S. Huang, and K. N. Tu, "Silicide formation in implanted channels and interfacial reactions of metal contacts under high current density," J. Mater. Res. 14, 4720-4726 (1999).

66. C. N. Liao, Y. P. Tsai, Y. Xu, K. N. Tu, B. Zhao, Q. Z. Liu, and Maureen Brongo, "Thermal conductivity measurement of low-k inter-layer-dielectric thin films," J. Appl. Phys. (submitted).

67. K. N. Tu, C. C. Yeh, C. Y. Liu, and Chih Chen, "Effect of current crowding on vacancy diffusion and void formation in electromigration," Appl. Phys. lett., 76, 988-990 (2000).

68. D. W. Zheng, Y. H. Xu, Y. P. Tsai, K. N. Tu, P. Patterson, Bin Zhao, Q. Z. Liu, and Maureen Brongo, "Mechanical property measurement of thin polymeric low dielectric constant films using bulge testing methods," Appl. Phys. lett., 76, 2008-2010 (2000).

69. J. S. Huang, Chih Chen, C. C. Yeh, K. N. Tu, T. L. Shofner, J. D. Drown, R. B. Irwin, and C. B. Vartuli, "Effect of current crowding on contact failure in heavily doped n+- and p+-silicon-on-insulator," J. Mater. Res. , 15, 2387-2392 (2000).

70. P. S. Nam, L. M. Ferreira, T. Y. Lee, and K. N. Tu, "Study of grass formation in GaAs backside via etching using inductively coupled plasma system," J. Vac. Sci. Tech., B18, 2780-2784 (2000).

71. J. W. Jang, D. R. Frear, T. Y. Lee, and K. N. Tu, "Morphology of interfacial reaction between Pb-free solders and electroless Ni(P) under-bump-metallization," J. Appl. Phys., 88, 6359-6363 (2000).

72. T. Y. Lee, K. N. Tu, S. M. Kuo, and D. R. Frear, "Electromigation of eutectic SnPb solder interconnects for flip chip technology," J. Appl. Phys., 89, 3189-3194 (2001).

73. Everett C. C. Yeh and K. N. Tu, "Effects of contact resistance and film thickness on current crowding and critical product of electromigration in Blech structures," J. Appl. Phys., 89, 3203-3208 (2001).

74. Q. T. Huynh, C. Y. Liu, Chih Chen, and K. N. Tu, "Electromigration in eutectic PbSn solder lines," J. Appl. Phys. , 89, 4332-4335 (2001).

75. K. N. Tu, T. Y. Lee, J. W. Jang, L. Li, D. R. Frear, K. Zeng, and J. K. Kivilahti, "Wetting reaction vs. solid state aging of eutectic SnPb on Cu," J. Appl. Phys. 89, 4843-4849 (2001).

76. K. N. Tu and K. Zeng, "Tin-lead (SnPb) solder reaction in flip chip technology," Materials Science & Engineering reports, R34, 1-58 (2001)

77. K. N. Tu, response to comments on "Effect of current crowding on vacancy diffusion and void formation in electromigration," Appl. Phys. Lett., 79, 1063 (2001).

78. K. N. Tu, Fiona Ku, and T. Y. Lee, "Morphology stability of solder reaction products in flip chip technology," J. Electronic Materials, 30, 1129-1132 (2001).

79. T. Y. Lee, K. N. Tu, and D. R. Frear, "Electromigration of eutectic SnPb and SnAgCu flip chip solder bumps and under-bump-metallization," J. Appl. Phys., 90, 4502-4508 (2001).

80. T. Y. Tom Lee, T. Y. Lee, and K. N. Tu, "A study of electromigration in 3-D flip chip solder joint using numerical simulation of heat flux and current density," 2001 IEEE ECTC Proceedings, pp. 558-563 (2001).

81. C. Y. Liu, Jian Li, G. J. Vandentop, W. J. Choi, and K. N. Tu, "Wetting reaction of Sn-Ag based solder systems on Cu substrates plated with Au," J. Electronic Materials, 30, 521-524 (2001)

82. D. R. Frear and K. N. Tu, "Metallurgical Factors," Chapter 28 in "Area Array Interconnection Handbook" edited by K. Puttlitz and P. A. Totta, Kluwer Academic Publishers, Boston (2001) pp. 1108-1144. (Book chapter)

83. H. H. Lin, S. L. Cheng, L. J. Chen, Chih Chen and K. N. Tu, "Enhanced dopant activation and elimination of end-of-range defects in BF2-implanted silicon-on-insulator by high-density current," Appl. Phys. Lett., 79, 3971-3973 (2001)

84. F. Kun, W. Wen, K.F. Pal, and K. N. Tu, "Break-up of dipolar rings under a perpendicular magnetic field," Phys. Rev. E64, 061503-1 to -8 (2001).

85. Everett C.C. Yeh, W.J. Choi, K.N. Tu, P. Elenius, H. Balkan, "Current-crowding-induced electromigration failure in flip chip solder joints," Appl. Phys. Lett., 80(4), 580-2 (2002).

86. T. Y. Lee, W. J. Choi, K. N. Tu, J. W. Jang, S. M. Kuo, J. K. Lin, D. R. Frear, K. Zeng, and J. K. Kivilahti, "Morphology, kinetics, and thermodynamics of solid state aging of eutectic SnPb and Pb-free solders (SnAg, SnAgCu, and SnCu) on Cu," J. Materials Research. , 17, 291-301 (2002).

87. Z. B. Zhang, J. S. Huang, M. Twiford, E. Martin, N. Layadi, A. Salah, B. Bhowmik, D. Vitkavago, S. Lytle, E. C. C. Yeh, and K. N. Tu, "A robust multilevel interconnect module for sub-quarter-micrometer complementary metal oxide semiconductor technology integration," J. of Electrochemical Society, 149, G324-G329 (2002).

88. K. Zeng and K. N. Tu, "Six cases of reliability study of Pb-free solder joints in electron packaging technology," Materials Science and Engineering Reports, R38, 55-105 (2002). (A review paper.)

89. W. J. Choi, T. Y. Lee, K. N. Tu, N. Tamura, R. S. Celestre, A. A. MacDowell, Y. Y. Bong, L. Nguyen, and G. T. T. Sheng, "Structure and kinetics of Sn whisker growth on Pb-free solder finish," 52nd Electronic Component & Technology Conference Proceedings (IEEE Catalog number 02CH3734-5), San Diego, CA, 628-633 (2002).

90. K. N. Tu, and K. Zeng, "Reliability issues of Pb-free solder joints in electronic packaging technology," 52nd Electronic Component & Technology Conference Proceedings, San Diego, CA, 1194-1200 (2002).

91. W. J. Choi, E. C. C. Yeh, and K. N. Tu, "Electromigration of flip chip solder bump on Cu/Ni(V)/Al thin film under bump metallization," 52nd Electronic Component & Technology Conference Proceedings, San Diego, CA, 1201-1205 (2002).

92. H. Gan and K. N. Tu, "Effect of electromigration on intermetallic compound formation in Pb-free solder - Cu interfaces," 52nd Electronic Component & Technology Conference Proceedings, San Diego, CA, 1206-1212 (2002).

93. H. Gan, W. J. Choi, G. Xu, and K. N. Tu, "Electromigration in flip chip solder joints and solder lines," JOM, 6, 34-37 (2002).

94. D. W. Zheng, X. H. Wang, K. Shyu, Chih Chen, C. T. Chang, K. N. Tu, A. J. Mal, and Y. F. Guo, "Stress relaxation of a patterned microstructure on a diaphragm," J. Materials Research, 17, 1795-1802 (2002).

95. M. Li, F. Zhang, W. T. Chen, K. Zeng, K. N. Tu, H. Balkan, and P. Elenius, "Interfacial microstructure evolution between eutectic SnAgCu solder and Al/Ni(V)/Cu thin films," J. Mater. Res., 17, 1612-1621 (2002).

96. G. T. T. Sheng, C. F. Hu, W. J. Choi, K. N. Tu, Y. Y. Bong, and Luu Nguyen, " Tin whiskers studied by focused ion beam imaging and transmission electron microscopy," J. Appl. Phys., 92, 64-69 (2002).

97. C. N. Liao and K. N. Tu, "Direct measurement of contact temperature using Seebeck potential," J. Appl. Phys., 92, 635-637 (2002).

98. A. M. Gusak and K. N. Tu, "Kinetic theory of flux-driven ripening," Phys. Rev. B66, 115403-1 to -14 (2002).

99. K. N. Tu, A. M. Gusak, and M. Li, "Physics and materials challenges for Pb-free solders," J. Appl. Phys., 93, 1335-1353 (2003). (Applied Physics Reviews - Focused Review)