Apparatus for monitoring thickness of deposited layer in reactor and dry processing method

A dry processing method of generating discharge in a processing chamber in a predetermined gas atmosphere to process an object to be processed so that a deposit produced in the processing chamber is cleaned, comprising:

• irradiating a measurement window, which is formed in an inner wall surface of the processing chamber and can transmit light, with measurement light at an incident angle that said measurement light is totally reflected by an inner surface of said measurement window;
• focussing said measurement light reflected by the inner surface of said measurement window and a surface of a layer deposited on the inner surface to detect said measurement light;
• evaluating the layer deposited on the inner surface of said measurement window on the basis of the detected reflected light of said measurement light;
• and
• deciding a time of cleaning the deposit produced in the processing chamber on the basis of the evaluation of the deposited layer.

A dry processing apparatus for generating discharge in a processing chamber in a predetermined gas atmosphere to process an object to be processed so that a deposit produced in the processing chamber is cleaned, comprising:

• a measurement window which is formed in an inner wall surface of the processing chamber and can transmit light;
• means for irradiating said measurement window with measurement light at an incident angle that said measurement light is totally reflected by an inner surface of said measurement window on the side of an inner wall surface of the processing chamber;
• detection means for focusing said measurement light reflected by the inner surface of said measurement window and a surface of a layer deposited on the inner surface to detect said measurement light;
• and
• means for evaluating the layer deposited on the inner surface of said measurement window on the basis of the detection result of said detection means and deciding a time of cleaning the deposit produced in the processing chamber on the basis of the evaluation of the deposited layer.