Patent ID: 9741629
Date: 2017-08-22
CPC Classifications: H01J,H01L

Claim:
1. A plasma processing method of processing a layer structure previously formed on an upper surface of a wafer disposed in a processing chamber within a vacuum container by means of plasma generated in the processing chamber, the layer structure including a layer to be processed and an undercoating layer disposed under the layer to be processed, the method comprising: calculating an etching amount of the layer to be processed at a time during processing of the wafer by using a result of comparing real pattern data which indicates a pattern of intensity of interference light having as a parameter a wavelength thereof obtained at a time during the processing of the wafer with detection pattern data obtained in advance by combining two patterns of data selected from three or more patterns of data each of which indicate the intensity of the interference light detected from a plurality of layer structures, wherein each said layer structure contains said undercoating layer having a thickness which is different for each said layer structure; and judging arrival at a target of the processing of the layer to be processed using the etching amount.