Patent ID: 8049872

Claim:
An endpoint detection device comprising: an Optical Emission Spectrometer (OES) data operation unit for processing reference OES data by normalization and Principal Component Analysis (PCA), outputting linear reference loading vectors and rate values of reference principal components, and outputting reference ranking values on the basis of the linear reference loading vectors; a data selector for first selecting part of the linear reference loading vectors on the basis of the rate values of the reference principal components, selecting part of the reference OES data or selecting part of process OES data on the basis of the reference ranking values, and second selecting part of the first selected linear reference loading vectors on the basis of the reference ranking values; a product generator for outputting at least one reference product value on the basis of the first selected linear reference loading vectors and the reference OES data; a Support Vector Machine (SVM) for performing regression on the basis of the selected reference OES data and the at least one reference product value, generating nonlinear reference loading vectors, and periodically outputting a prediction product value on the basis of the second selected linear reference loading vectors, the nonlinear reference loading vectors, and the selected process OES data; and an endpoint determiner for detecting a process wafer etch or deposition endpoint on the basis of the periodically received prediction product value and outputting a detection signal, wherein first lights of a whole wavelength emitted from the inside of a plasma reaction chamber are converted into the reference OES data by a spectrometer during a reference wafer etch or deposition process and second lights of a whole wavelength emitted from the inside of the plasma reaction chamber are converted into the process OES data by the spectrometer during a process wafer etch or deposition process executed after the reference wafer etch or deposition process, wherein the reference ranking values represent a ranking for the intensity of the first lights of the whole wavelength, and wherein the linear reference loading vectors each correspond to one-dimensional function values expressed by the reference OES data and the nonlinear reference loading vectors each correspond to S-dimensional, wherein S: integer larger than 1, function values expressed by the selected process OES data.