METHOD OF DECIDING ENDING POINT OF OXYGEN-FREE PLASMA TREATMENT

摘要

PURPOSE: A method of deciding ending point of oxygen-free plasma treatment is provided to accurately detect the ending point of ashing for non oxygen plasma peeling treatment. CONSTITUTION: In this method of deicing the ending point of non-oxygen plasma treatment, used at the working of a semiconductor wafer, and non- oxygen plasma is generated by exciting a gas composition, containing a nitrogen gas and a reactive gas and is made to react to a substrate(88) carrying a photoresist/residues. The ending point is decided by optically measuring the first optically discharged signal of the resulted product of an oxygen-free resection at a wavelength of about 387 nm. When the plasma does not react to the substrate(88) any longer, the generating time of the optically discharged signal with the wavelength of about 387 nm is decided as the ending point and is displayed that the photoresist/residues are removed from the wafer. It is also possible to decide the ending point by monitoring the second optically discharged signal of the resulted product of the oxygen-free reaction at wavelengths of about 358 nm and 431 nm.