K. Ikeda et Y. Oshita, NUMERICAL-ANALYSIS OF THE PRESSURE-DEPENDENCE OF THE ETCH RATE IN AN AL ETCHING REACTOR EQUIPPED WITH A HELICON SOURCE, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 16(1), 1998, pp. 159-163
The pressure dependence of the etch rate in an Al etching reactor has
been studied with the goal of developing a method of numerically simul
ating the etching process. Experimentally, the etch rate was measured
at pressures between 3 and 100 mTorr and reached a maximum at about 10
mTorr, whereas the calculated etch rate, which took the etching react
ion between Al and Cl-2 on an Al surface into account, increased with
pressure. To explain the experimental data, the residence time tau(0)
Of the inhibitor adsorbed on the Al surface and time-averaged surface
coverage were included in the calculations. In the low-pressure region
below 10 mTorr, the etch rate increased with an increase in pressure,
due to the increased Cl-2 flux on the Al surface. On the other hand,
in the high-pressure region over 10 mTorr, the etch rate decreased whe
n the effect of the inhibitor became stronger; this was explained by d
eveloping an improved model. Consideration of the inhibitor adsorbed o
n the Al surface is important, where the increase of tau(0) with press
ure is necessary to precisely simulate the correlation between the etc
h rate and pressure. (C) 1998 American Vacuum Society.