Studies on rarefied gas flow of radicals and surface reactions in a high-density plasma reactor

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We describe the theoretical and experimental results of this study.1 Theoretical results(1) The physical and chemical phenomena in an ICP reactor are analyzed using DSMC and PIC/MC methods.The etch rate increases with increasing mass flow rate and the region of nonuniform etch rate becomes wider as the flow rate decreases.The deviation of EEDF from the Maxwellian becomes small due to Coulomb collisions for smaller coil current.(2) Etching of silicon wafer by chlorine gas in a CCP reactor is studied by use of a combined analysis of the DSMC and PIC/MC methods.The etch rate is uniform in most of tea wafer. It shows a sharp rise near the wafer edge.The electron density is two-order lower than the negative chlorine radical ion density in the afterglow of RF chlorine discharge plasma.(3) We proposed a new useful particle modeling to simulate the ICP reactor. In this work, production and transport of plasma and radicals are calculated using this modeling. Our simulation and experiment show a good agreement with each other.2 Experimental results(1) We examined the argon plasma properties in an ICP reactor.The electron density is in the region of 1×10^<10>〜1×10^<11> cm^3, electron temperature 4〜6eV, and plasma potential 35〜45V.(2) We examined the silicon etching properties of cw discharge and pulsed discharge in the chlorine plasma. The results of the cw discharge are as follows :The distribution of the etch rate is very uniform over the wafer surface.The etch depth depends on the etching time linearly.(3) The results of the pulsed discharge are as follows :The etch rate increases with decreasing the duty ratio butit is saturated about 33% of duty ratio.As the duty ratio decreases, the distribution of the etch rate becomes more nonuniform.