V. Gopinath et al., ELECTRON-CYCLOTRON-RESONANCE SPUTTER REMOVAL OF SIO2 ON SILICON-WAFERS, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 11(6), 1993, pp. 2067-2070
The in situ sputter removal of oxide layers prior to subsequent deposi
tions or growth is increasingly important as device sizes and hence in
terlayer contact sizes shrink. Electron cyclotron resonance (ECR) plas
ma sputter removal of oxides has been investigated since it offers the
combination of high plasma densities and low ion energy induced subst
rate damage. In this study, ECR argon discharge sputter removal of SiO
2 was investigated using a 9 and 25 cm diam discharge. The uniformity
and rate of oxide removal on 3 and 6 in. silicon wafers were investiga
ted with respect to pressure (0.6-2 mTorr), microwave power (200-800 W
), radio-frequency induced bias (-30 to -80 V) and downstream position
(6.3-11.8 cm) of the wafer. Uniformity and rate results show good cor
relation to ion density measurements and to an ambipolar plasma diffus
ion model.