Abstract: This invention includes a first filter (27) connected between a susceptor (21) and ground and having a variable impedance, a sensor (28) for detecting an electrical signal based on the state of a plasma (P) generated in a process chamber (11), and a control means (36) for controlling the impedance of the first filter (27) on the basis of a detection result output from the sensor (28). Thus, a preferable plasma distribution to match the object of the plasma process can be realized.

Abstract: An apparatus, which performs a plasma process on a target substrate by using plasma, includes first and second electrodes in a process chamber to oppose each other. An RF field, which turns a process gas into plasma by excitation, is formed between the first and second electrodes. An RF power supply, which supplies RF power, is connected to the first or second electrode through a matching circuit. The matching circuit automatically performs input impedance matching relative to the RF power. A variable impedance setting section is connected to a predetermined member, which is electrically coupled with the plasma, through an interconnection. The impedance setting section sets a backward-direction impedance against an RF component input to the predetermined member from the plasma. A controller supplies a control signal concerning a preset value of the backward-direction impedance to the impedance setting section.

Abstract: A method of detecting an etching depth of a target object includes the steps of irradiating an etching layer of the target object that is being etched in an etching section with light having a plurality of components differing from each other in a wavelength, detecting a plurality of interference light components differing from each other in the wavelength and having an intensity periodically changed by the light components reflected from an upper surface of the etching layer and a surface of the etching section, applying a frequency analysis to these interference light components so as to obtain the frequency of each of these interference wave forms in which the intensity forms the amplitude, calculating an etching rate corresponding to each interference wave form by using the frequency of the interference wave form, and obtaining an etching depth from the etching rate.

Abstract: A method of detecting an etching depth of a target object includes the steps of irradiating an etching layer of the target object that is being etched in an etching section with light having a plurality of components differing from each other in a wavelength, detecting a plurality of interference light components differing from each other in the wavelength and having an intensity periodically changed by the light components reflected from an upper surface of the etching layer and a surface of the etching section, applying a frequency analysis to these interference light components so as to obtain the frequency of each of these interference wave forms in which the intensity forms the amplitude, calculating an etching rate corresponding to each interference wave form by using the frequency of the interference wave form, and obtaining an etching depth from the etching rate.