Spatial distributions of ion-species in a large-volume inductively coupledplasma source

Distributions of plasma parameters, such as electron temperature and electr on density have been studied for large-volume processing. In terms of preci se study of large-volume plasma, ion-species distributions in plasma should be measured as well as those of plasma parameters. However, no method to m easure the spatial distributions of ion species has been developed so far. In this study, we construct a new apparatus to measure the ion-species dist ribution by using a quadrupole mass spectrometer, which can be moved in vac uum perpendicularly to the beam extraction. Furthermore, we propose a new m ethod to generate uniform plasma by introducing gas in pulse and generate p ulsed plasma correspondently with the gas introduction. The results suggest that the ion-species distributions are not consistent with the electron-de nsity distribution and spatial distributions of ion species can be improved by introducing gas in pulse and generating pulsed plasma. For further stud y towards the next-generation semiconductor fabrication, the ion-species di stributions in large-volume plasma should be taken into account as well as those of the other plasma parameters. (C) 2001 Elsevier Science B.V. All ri ghts reserved.