| 摘要 |
PURPOSE:To accurately detect the ending point of decomposing reaction by detecting the quantity of a light to be absorbed to a decomposing gas generated by the decomposing reaction of organic matter coated on the surface of a material to be treated, thereby detecting the ending point of the reaction. CONSTITUTION:When an organic matter coated on the surface of an object 4 to be treated is removed by decomposing with predetermined processing gas, the quantity of the light to be absorbed to the decomposing gas generated by the decomposing reaction of the organic matter is detected thereby to detect the ending point of the reaction. That is, when the light irradiated from a light emission body 11 is absorbed, the quantity of the light which arrives at photodetecting means 12 from the L.E. body 11 is reduced as compared with that before the decomposing reaction is started. Thus, the quantity of generated decomposed gas and hence the ending point of the reaction can be accurately detected on the basis of the variation in the quantity of the light without depending upon the quantity of the organic matter being coated in advance on the surface of the object to be processed. |
