Recently, short-pulse lasers have been applied to microfabrication in the field of various industries. It becomes more difficult to experimentally observe the microfabrication phenomena as pulse width becomes short. Numerical analysis with a continuum model has a limit in elucidation of such phenomena, therefore, computer simulations at the atomic or molecular level must be important. The authors have conducted the molecular dynamics simulation of laser materials processing over the years. In this paper, a modified molecular dynamics method for metal developed by the authors, where calculation of the molecular dynamics is carried out while revising the heat conduction by free electrons at each time step, was applied to elucidate the laser microfabrication phenomena. Pulse width dependence of damage threshold, evaporation process, velocity distribution of evaporation particles and temperature profile near the surface were investigated.

1.
For example,
M.C.
Downer
,
R.L.
Fork
and
C.V.
Shank
:
Femtosecond Image of Melting and Evaporation at a Photoexcited Silicon Surface
,
Opt. Soc. Am
. B,
2
, (
1985
),
595
.
2.
For example,
J.R.
Ho
,
C.P.
Grigoropoulos
and
J.A.C.
Humphrey
:
Computational Study of Heat Transfer and Gas Dynamics in the Pulsed Laser Evaporation of Metals
,
J. Appl. Phys.
,
78
, (
1995
),
4696
.
3.
E.
Ohmura
and
I.
Fukumoto
:
Computer Simulation on Fusion and Evaporation of Metal with Laser Irradiation
,
J. High-Temperature Society
,
20
, (
1994
),
228
.
4.
E.
Ohmura
and
I.
Fukumoto
:
Molecular Dynamics Simulation on Laser Ablation of fcc Metal
,
Int. J. Japan Soc. Prec. Eng.
,
30
, (
1996
)
128
.
5.
E.
Ohmura
and
I.
Fukumoto
:
Modified Molecular Dynamics Simulation on Laser Ablation of Metal
,
International Journal of Japan Society for Precision Engineering
,
31
, (
1997-9
)
206
207
.
6.
U.
Grigull
and
H.H.
Sandner
:
Heat Conduction
,
Springer-Verlag
, (
1984
),
7
.
7.
Y.H.
Touloukian
,
R. W.
Powell
,
C. Y.
Ho
and
P.G.
Klements
ed.:
Thermophysical Properties of Matter
,
1
,
Plenum
, (
1970
),
9
.
8.
W.J.
Parker
,
R.J.
Jenkins
,
C.P.
Buther
and
G.L.
Abott
:
Flash Method of Determining Thermal Diffusivity, Heat Capacity, and Thermal Conductivity
,
J. Appl. Phys.
,
32
, (
1961
),
1679
.
9.
J.F.
Ready
:
Effects of High Power Laser Radiation
,
Academic Press
, (
1971
),
72
.
10.
B.C.
Stuart
,
M.D.
Feit
,
A.M.
Rubenchik
,
B.W.
Shore
, and
M.D.
Perry
:
Optical Ablation by High-Power Short-Pulse Lasers
,
J. Opt. Soc.
,
B13
, (
1996
),
459
.
11.
P.P.
Pronko
,
S.K.
Dutta
,
D. Du and R.K.
Singh
:
Thermophysical Effects in Laser Processing of Materials with Picosecond and Femto-second Pulses
,
J. Appl. Phys.
,
78
, (
1995
),
6233
.
12.
A.
Rosenfeld
,
D.
Ashkenasi
,
H.
Varel
,
M.
Wahmer
and
E.E.B.
Camp-bell
:
Time Resolved Detection of Particle Removal from ielectrics on Femtosecond Laser Ablation
,
Appl. Surf. Sci.
,
127-129
, (
1998
),
76
80
.
13.
H.
Wang
,
A.P.
Salzberg
and
B.R.
Weiner
:
Laser Ablation of Aluminum at 193, 248, and 351 nm
,
Appl. Phys. Lett.
,
59
, (
1991
),
935
.
14.
C.
Momma
,
B.N.
Chichkov
,
S.
Nolte
,
F.
von Alvensleben
,
A
Tonnermann
,
H.
Welling
and
R
Wellegehausen
:
Short-Pulse Laser Ablation of Solid Targets
,
Optics Comm.
,
129
, (
1996
),
134
.
This content is only available via PDF.
You do not currently have access to this content.