Patent ID: 6515293
Filing Date: 2003-02-04
Classification: G01B,H01L

Abstract:
A method of detecting the thickness of a thin layer, comprising:(a) providing a sample wafer having a plurality of cells, an oxide site disposed laterally adjacent each of the cells, and a thin layer formed over the cells and each said oxide site adjacent thereto, each of the cells comprising a patterned layer disposed on a substrate, and the oxide site being devoid of the patterned layer; (b) irradiating white light towards one of the cells of the sample wafer, collecting light reflecting from the cell, dividing the white light into components including red and green light, and obtaining respective values of the luminance of red and green components of the collected light; (c) detecting the thickness of the thin layer at the oxide site adjacent the cell; (d) repeating (b) and (c) a plurality of times to obtain a plurality of luminance values corresponding to the luminance of the green light from a plurality of the cells, respectively, a plurality of luminance values corresponding to the luminance of the red light from the plurality of the cells, respectively, and a plurality of thickness values corresponding to the detected thicknesses of the thin layer at the oxide sites adjacent the cells, respectively; (e) using a plurality of luminance values obtained only in (d) and a plurality of the thickness values obtained in (d) to establish a thickness calculation formula for the green light and for the red light; and (f) determining the thickness of a top layer in a cell of a wafer of a device under manufacture using the thickness calculation formula for the green light and for the red light.