New methods of removing surface contaminants from microelectronic and microelectromechanical systems (MEMS) devices are needed since the decreasing size of their components is reducing the allowable contamination levels. By choosing the pulse duration and fluence to optimize electronic rather than thermal desorption in short-pulse laser processing, surface species can be removed without exceeding maximum temperature constraints. A two-temperature model for short-pulse laser heating of, and subsequent desorption from, metal surfaces is presented. A scaling analysis indicates the material properties and laser parameters on which the ratio of electronic to thermal desorption depends. Regimes of predominantly electronic and thermal desorption are identified, and predicted desorption yields from gold films show that electronic desorption is the primary desorption mechanism in certain short-pulse laser processes.
Issue Section:
Micro-Scale Heat Transfer
1.
Anisimov
S. I.
Kapeliovich
B. L.
Perel’man
T. L.
1974
, “Electron Emission from Metal Surfaces Exposed to Ultrashort Laser Pulses
,” Soviet Physics JETP
, Vol. 39
, pp. 375
–377
.2.
Brorson
S. D.
Fujimoto
J. G.
Ippen
E. P.
1987
, “Femtosecond Electronic Heat-Transport Dynamics in Thin Gold Films
,” Physical Review Letters
, Vol. 59
, pp. 1962
–1965
.3.
Brorson
S. D.
Kazeroonian
A.
Moodera
J. S.
Face
D. W.
Cheng
T. K.
Ippen
E. P.
Dresselhaus
M. S.
Dresselhaus
G.
1990
, “Femtosecond Room-Temperature Measurement of the Electron-Phonon Coupling Constant λ in Metallic Super-conductors
,” Physical Review Letters
, Vol. 64
, pp. 2172
–2175
.4.
Budde
F.
Heinz
T. F.
Loy
M. M. T.
Misewich
J. A.
de Rougemont
F.
Zacharias
H.
1991
, “Femtosecond Time-Resolved Measurement of Desorption
,” Physical Review Letters
, Vol. 66
, pp. 3024
–3027
.5.
Busch
D. G.
Gao
S.
Pelak
R. A.
Booth
M. F.
Ho
W.
1995
, “Femtosecond Desorption Probed by Time-Resolved Velocity Measurements
,” Physical Review Letters
, Vol. 75
, pp. 673
–676
.6.
Cavanagh
R. R.
Buntin
S. A.
Richter
L. J.
King
D. S.
1990
, “Laser Induced Desorption of Molecules from Surfaces
,” Comments on Atomic and Molecular Physics
, Vol. 24
, pp. 365
–376
.7.
Comizzoli
R. B.
Frankenthal
R. P.
Milner
P. C.
Sinclair
J. D.
1986
, “Corrosion of Electronic Materials and Devices
,” Science
, Vol. 234
, pp. 340
–345
.8.
Elsayed-Ali
H. E.
Norris
T. B.
Pessot
M. A.
Mourou
G. A.
1987
, “Time-Resolved Observation of Electron-Phonon Relaxation in Copper
,” Physical Review Letters
, Vol. 58
, pp. 1212
–1215
.9.
Fann
W. S.
Storz
R.
Tom
H. W. K.
Bokor
J.
1992
, “Direct Measurement of Nonequilibrium Electron-Energy Distributions in Subpicosecond Laser-Heated Gold Films
,” Physical Review Letters
, Vol. 68
, pp. 2834
–2837
.10.
Fushinobu
K.
Phinney
L. M.
Tien
N. C.
1996
, “Ultrashort-Pulse Laser Heating of Silicon to Reduce Microstructure Adhesion
,” International Journal of Heat and Mass Transfer
, Vol. 39
, pp. 3181
–3186
.11.
Grey, D. E., ed., 1972, American Institute of Physics Handbook, 3rd Ed., McGraw-Hill, New York.
12.
Groeneveld
R. H. M.
Sprik
R.
Lagendijk
A.
1990
, “Ultrafast Relaxation of Electrons Probed by Surface Plasmons at a Thin Silver Film
,” Physical Review Letters
, Vol. 64
, pp. 784
–787
.13.
Incropera, F. P., and DeWitt, D. P., 1990, Fundamentals of Heat and Mass Transfer, 3rd Ed., John Wiley and Sons, New York.
14.
Kaganov
M. I.
Tanatarov
L. V.
1957
, “Relaxation between Electrons and the Crystalline Lattice
,” Soviet Physics JETP
, Vol. 4
, pp. 173
–178
.15.
Kao
F.-J.
Busch
D. G.
Gomes da Costa
D.
Ho
W.
1993
a, “Femtosecond versus Nanosecond Surface Photochemistry: O2 + CO on Pt(111) at 80 K
,” Physical Review Letters
, Vol. 70
, pp. 4098
–4101
.16.
Kao
F.-J.
Busch
D. G.
Cohen
D.
Gomes da Costa
D.
Ho
W.
1993
b, “Femtosecond Laser Desorption of Molecularly Adsorbed Oxygen from Pt(111)
,” Physical Review Letters
, Vol. 71
, pp. 2094
–2097
.17.
Kittel, C., 1986, Introduction to Solid State Physics, 6th Ed., John Wiley and Sons, New York.
18.
Klemens
P. G.
Williams
R. K.
1986
, “Thermal Conductivity of Metals and Alloys
,” International Metals Reviews
, Vol. 31
, pp. 197
–215
.19.
Leech
C. S.
1994
, “Removing Moisture from Electronic Components and Assemblies
,” Circuit Assembly
, Vol. 5
, pp. 34
–37
.20.
Legtenberg
R.
Tilmans
H. A. C.
Elders
J.
Elwenspoek
M.
1994
, “Stiction of Surface Micromachined Structures after Rinsing and Drying: Model and Investigation of Adhesion Mechanisms
,” Sensors and Actuators A
, Vol. 43
, pp. 230
–238
.21.
Park
H. K.
Grigoropoulos
C. P.
Leung
W. P.
Tarm
A. C.
1994
, “A Practical Excimer Laser-Based Cleaning Tool for Removal of Surface Contaminants
,” IEEE Transactions on Components, Packaging, and Manufacturing Technology-Part A
, Vol. 17
, pp. 631
–643
.22.
Patankar, S. V., 1980, Numerical Heat Transfer and Fluid Flow, Hemisphere, New York.
23.
Pells
G. P.
Shiga
M.
1969
, “The Optical Properties of Copper and Gold as a Function of Temperature
,” Journal of Physics C.
, Vol. 2
, pp. 1835
–1846
.24.
Phinney, L. M., 1997, “Electronic Desorption and Microstructure Adhesion Reduction Using Ultrashort-Pulse Lasers,” Ph.D. thesis, University of California, Berkeley, CA.
25.
Prybyla
J. A.
Heinz
T. F.
Misewich
J. A.
Loy
M. M. T.
Glownia
J. H.
1990
, “Desorption Induced by Femtosecond Laser Pulses
,” Physical Review Letters
, Vol. 64
, pp. 1537
–1540
.26.
Prybyla
J. A.
Tom
H. W. K.
Aumiller
G. D.
1992
, “Femtosecond Time-Resolved Surface Reaction: Desorption of CO from Cu(111) in <325 fsec
,” Physical Review Letters
, Vol. 68
, pp. 503
–506
.27.
Qiu, T. Q., 1993, “Energy Deposition and Transport during High-Power and Short-Pulse Laser-Metal Interactions,” Ph.D. thesis, University of California, Berkeley, CA.
28.
Qiu
T. Q.
Tien
C. L.
1993
a, “Heat Transfer Mechanisms during Short-Pulse Laser Heating of Metals
,” ASME JOURNAL OF HEAT TRANSFER
, Vol. 115
, pp. 835
–841
.29.
Qiu
T. Q.
Tien
C. L.
1993
b, “Size Effects on Nonequilibrium Laser Heating of Metal Films
,” ASME JOURNAL OF HEAT TRANSFER
, Vol. 115
, pp. 842
–847
.30.
Qiu
T. Q.
Tien
C. L.
1994
, “Femtosecond Laser Heating of Multi-Layer Metals—I. Analysis
,” International Journal of Heat and Mass Transfer
, Vol. 37
, pp. 2789
–2797
.31.
Schoenlein
R. W.
Lin
W. Z.
Fujimoto
J. G.
Eesley
G. L.
1987
, “Femtosecond Studies of Nonequilibrium Electronic Processes in Metals
,” Physical Review Letters
, Vol. 58
, pp. 1680
–1683
.32.
Scouler
W. J.
1967
, “Temperature-Modulated Reflectance of Gold from 2 to 10 eV
,” Physical Review Letters
, Vol. 18
, pp. 445
–448
.33.
Shumay
W. C.
1987
, “Corrosion in Electronics
,” Advanced Materials and Processes
, Vol. 132
, pp. 73
–77
.34.
Tien
N. C.
Jeong
S.
Phinney
L. M.
Fushinobu
K.
Bokor
J.
1996
, “Surface Adhesion Reduction in Silicon Microstructures Using Femtosecond Laser Pulses
,” Applied Physics Letters
, Vol. 68
, pp. 197
–199
.35.
Walsh
S. T.
Boylan
R.
Bart
S. F.
1995
, “Overcoming Stiction in MEMS Manufacturing
,” Micro
, Vol. 13
, pp. 49
–50
.36.
Woodruff, D. P., and Delchar, T. A., 1994, Modern Techniques of Surface Science, 2nd Ed., Cambridge University Press, Cambridge, England.
37.
Yoo, K. M., Zhao, X. M., Siddique, M., Alfano, R. R., Osterman, D. P., Rad-parvar, M., and Cunniff, J., 1990, “Rate of Electron-Phonon Relaxation in Niobium,” Ultrafast Phenomena VII, C. B. Harris et al., ed., Springer-Verlag, Berlin, pp. 357–359.
38.
Zhdanov
V. P.
1991
, “Arrhenius Parameters for Rate Processes on Solid Surfaces
,” Surface Science Reports
, Vol. 12
, pp. 183
–242
.39.
Zhu
X.-Y.
1994
, “Surface Photochemistry
,” Annual Review of Physical Chemistry
, Vol. 45
, pp. 113
–144
.
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