Patent ID: 7175875

Claim:
A method for processing a specimen using a plasma, comprising: generating a plasma in a processing chamber in which the specimen is disposed; processing the specimen with the plasma generated in the processing chamber; and performing contaminant analysis, which includes: an irradiation operation for projecting and scanning a light beam into the processing chamber through an observation window of the processing chamber; a detection operation for detecting a reflected light signal corresponding to a reflected light of the projected light beam which is reflected from an inside wall of the processing chamber, the reflected light signal being detected by separating a wall-reflected light component from light emanated from the plasma; and a signal processing operation for obtaining information on a state of contamination of the inside wall of the processing chamber, by processing the wall-reflected light signal obtained at the detection operation, by referring to an electronic database storing predetermined relationships between candidate signals obtainable from said detection of light from said inside wall and corresponding states of inside-wall contamination, to derive a state of contamination corresponding to the wall-reflected light signal, from the electronic database.