Thermosonic bonding is being widely used for wire bonding and tape automated bonding (TAB). It is also being developed for flip-chip assemblies. The bonding process is sensitive to system parameters such as ultrasonic frequency, bonding tool length, and friction. One of the process control challenges is to prevent the random change of vibration modes. The change from an axial to a bending mode excitation may reduce the ultrasonic vibration amplitude at the bonding interface and result in poor bond quality. In this work, we have studied the random mode change effected by tool length, friction, and the frequency window selected for the power generator. In one case, the mode change was not observed when the tool end extended 2.32 cm below the longitudinal axis of the bonding horn. In the other case, however, the resonant frequency switched between 58.4 and 60.0 kHz when the tool moved 0.31 cm downward with all other system parameters held constant. Such a frequency shift resulted in a change of vibration amplitudes between 1.63 and 0.55 μm. Different random mode changes measured were explained by our theoretical models consisting of a modal analysis for the system and a vibration model for the tool. The models generated a guideline to prevent mode change by selecting the right system parameters.

Issue Section:
Technical Papers
Topics:
Bonding, Vibration, Friction, End effectors, Excitation, Flip-chip assemblies, Generators, Modal analysis, Process control, Resonance, Wire bonding
1.
Harman, G. G., and Leedy, K. O., 1972, “An Experimental Model of the Microelectronic Ultrasonic Wire Bonding Mechanism,” Proc. Reliability Physics Syrup., pp. 49–56.
2.
Hu
S. J.
,
Lim
G. E.
,
Lira
T. L.
, and
Foong
K. P.
,
1991
, “
Study of Temperature Parameter on the Thermosonic Gold Wire Bonding of High-Speed CMOS
,”
IEEE Trans. On Components, Hybrids, and Manufacturing Technology
, Vol.
14
, No.
4
, pp.
855
–
858
.
3.
Hueners, B. M., 1983, “Absolute Ultrasonic Amplitude Measurement, Calibration and Troubleshooting of a Wire Bonding Using Laser Interferometer,” Proc. of ISHM Conf.
4.
Johnson
K. I.
,
Scott
M. H.
, and
Edson
D. A.
,
1977
, “
Ultrasonic Wire Bonding
,”
Solid State Technology
, Vol.
20
, No.
4
, pp.
91
–
95
.
5.
Kang
S. Y.
,
Williams
P. M.
, and
Lee
Y. C.
,
1995
, “
Modeling and Experimental Studies on Thermosonic Flip-Chip Bonding
,”
IEEE Trans. On Components, Products, and Manufacturing Technology, Part B. Advanced Packaging
, Vol.
18
, No.
4
, pp.
728
–
733
.
6.
McBrearty
M.
,
Kim
L. H.
, and
Bilgutay
N. M.
,
1988
, “
Analysis of Impedance Loading in Ultrasonic Transducer Systems
,”
Proc. IEEE Ultrasonics Symposium
, Vol.
1
, pp.
497
–
502
.
7.
McLaren
T.
,
Kang
S. Y.
,
Zhang
W.
, and
Lee
Y. C.
,
1994
, “
Thermosonic Bonding for Flip-Chip Assembly
,”
Advancing Microelectronics
, Vol.
21
, No.
4
, July/Aug., pp.
14
–
16
.
8.
Morris
R. B.
,
Carnevalli
P.
, and
Bandy
W. T.
,
1991
, “
Dynamics of an Ultrasonic Bonding Tool: A Case Study in p-Version Finite Element Analysis
,”
Jour. of Acoust. Soc. Am.
, Vol.
90
, No.
6
, pp.
2919
–
2923
.
9.
Onuki
J.
,
Suwa
M.
,
Koizumi
M.
, and
Iizuka
T.
,
1987
, “
Investigation of Aluminum Ball Bonding Mechanism
,”
IEEE Trans. on Components, Hybrids, and Manufacturing Technology
, Vol.
10
, No.
2
, pp.
242
–
246
.
10.
O’Shea, K., 1991, “Enhanced Vibration Control Ultrasonic Tooling Using Finite Element Analysis,” Vibration Analysis—Analytical and Computational ASME, Winter Annual Meeting, DE-Vol. 37, pp. 259–265.
11.
Paz, M., 1985, Structural Dynamics, 2nd ed., Van Nostrand Reinhold Company, NY, sect. 11.5.
12.
Przemieniecki, J. S., 1968, Theory of Matrix Structural Analysis, McGraw-Hill Book Company, NY, sect. 5.6, 11.5.
13.
Shirai, Y., Otsuka, K., Araki, T., Seki, I., Kikichi, K., Fujita, N., and Miwa, T., 1993, “High Reliability Wire Bonding by the 120 kHz Frequency of Ultrasonics,” ICEMM Proceedings, pp. 366–377.
14.
Operation and Maintenance Manual, 1985, Uthe Tech. Inc., Milpitas, CA.
15.
Viterbi, A. J., 1966, chap. 1 in Principles of Coherent Communication, McGraw-Hill Book Company, NY.
16.
Young, W. C., 1989, chap. 4 in Roark’s Formulas for Stress and Straining, 6th ed., McGraw-Hill Book Company, NY.
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