Patent ID: 6207007
Filing Date: 2001-03-27
Classification: H01J

Abstract:
A plasma processing system for carrying out a plasma process for processing a substrate by using a plasma produced by ionizing a process gas, said plasma processing system comprising:a processing vessel;a process gas supply system for supplying a process gas into the processing vessel;an evacuating system for evacuating the processing vessel;an electrode disposed in the processing vessel;a RF power generating means for supplying RF power to the electrode to produce a plasma by ionizing the process gas in the processing vessel;a pressure sensing means for measuring pressure in the processing vessel;a frequency measuring means for measuring the frequency of the RF power generated by the RF power generating means;a conversion means for relating the pressure in the processing vessel and the frequency of the RF power with the rate of the negative ion number density of the plasma produced in the processing vessel; anda control means for controlling the pressure in the processing vessel and the frequency of the RF power with reference to the conversion means so that the rate of the negative ion number density of the plasma is adjusted to a value.