Patent ID: 6231774
Filing Date: 2001-05-15
Classification: H01J

Abstract:
A plasma processing method for performing plasma processing on an object placed inside a reaction chamber by forming an electric field within said reaction chamber into which a processing gas is introduced and generating plasma that fluctuates over a given fluctuation cycle, comprising:(a) a step for obtaining sampling data by sampling plasma light of said plasma with a constant sampling period;(b) a step for hypothesizing a plurality of hypothetical fluctuation cycle, calculating a moving average values over each period corresponding to each of the hypothetical fluctuation cycles based upon said sampling data and obtaining a moving average value data for each of said hypothetical fluctuation cycles;(c) a step for obtaining an approximate expression corresponding to each of said hypothetical fluctuation cycles based upon said moving average value data for each of said hypothetical fluctuation cycles;(d) a step for ascertaining a deviation quantity between said moving average value data and a corresponding approximate expression for each of said hypothetical fluctuation cycles at one or two or more time points; and(e) a step for ascertaining a hypothetical fluctuation cycle having the smallest deviation quantity among said deviation quantities to determine said hypothetical fluctuation cycle as said fluctuation cycle of said plasma.