Method and Assembly for Determining the Thickness of a Layer in a Sample Stack

摘要

A method and an inspection assembly for determining the thickness of one or more layers of a sample stack of layers or other properties influencing the intensity of light reflected by the sample stack with an assembly comprising a light source for illuminating the sample stack of layers and a camera with a detector for detecting the intensity of light reflected by the sample stack of layers in defined wavelength ranges, the method comprising the steps of illuminating the sample stack of layers with light from the light source; detecting the intensity of light reflected by the sample stack of layers with the detector in different wavelength ranges; and determining the thickness or other property from the intensity detected by the detector; are characterized in that the detector is an array detector with a plurality of detector elements in lines and columns; an image of the sample stack of layers is generated on the detector; the detector comprises a plurality of sections in the form of parallel stripes, the stripes detecting the light reflected by the sample stack of layers simultaneously; light of one selected wavelength range only is detected by each of the plurality of sections of the detector; and a movement of the image of the sample stack of layers on the detector or of the parallel stripes is generated in a direction perpendicular to the longitudinal direction of the parallel stripes such that each point of the inspected sample stack of layers is detected at least once in each of the different wavelength ranges.

主权项

1. A method for determining the thickness of one or more layers of a sample stack of layers or other properties influencing the intensity of light reflected by said sample stack of layers with an assembly comprising
a light source emitting light for illuminating said sample stack of layers, said sample stack of layers reflecting said light from said light source with an intensity; and a camera with an array detector with a plurality of detector elements arranged in lines and columns for detecting said intensity of said light reflected by said sample stack of layers; and means for separating said intensity of said light reflected by said sample stack of layers in defined wavelength ranges, said defined wavelength ranges being at least partly different from each other; the method comprising the steps of: illuminating said sample stack of layers with said light from said light source; detecting said intensity of light reflected by said sample stack of layers with said detector in different wavelength ranges; and determining the thickness or other property from said intensity detected by said detector; and wherein an image of said sample stack of layers is generated on said detector; said detector comprises a plurality of sections in the form of parallel stripes, said stripes detecting said intensity of said light reflected by said sample stack of layers simultaneously; light of one of said wavelength ranges only is detected by each of said plurality of sections of said detector; and said parallel stripes have a longitudinal direction and a movement of said image of said sample stack of layers on said detector or of said parallel stripes is generated in a direction perpendicular to said longitudinal direction of said parallel stripes such that each point of said inspected sample stack of layers is detected at least once in each of said different wavelength ranges.