Appeal No. 2000-1608
Application 08/953,998
BACKGROUND
The disclosed invention relates to a method of simulating a
sputtering process. In Appellant's former simulation method,
described in connection with Fig. 1, the polar angular
distribution of extracted sputtered particles from a target
(i.e., atoms ejected from the surface further than a cut-off
distance) is calculated using the molecular dynamics (MD) method
for N particles, where N is limited to 100-200 because of
calculation time (step P1). Then the angular distribution of
ejection is read out (step P2) and used to calculate a track of
the sputtered particle by means of the Monte Carlo (MC) method,
and the sputtered particles which arrive at a specific region on
a wafer are extracted (step S5). The shape of the region where
the particles actually arrive is then calculated (step S6).
The problem with this former method is that the sampling
errors in directional components of the possible tracks of the
sputtered particles depend on the number of ejection angle
data N. Because N is as small as 100-200, the random number
error can be large. It is advantageous to make the number of
ejection angle data N as great as possible in order to minimize
the sampling error, but the number N needs to be kept small
because of the limitation in MD calculation time.
The invention creates a larger number of ejection angle
data from the calculated ejection angle data N. The calculated
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