Patent ID: 6476920
Filing Date: 2002-11-05
Classification: G01B,G01J,H01L

Abstract:
A method for measuring at least one desired parameter of a patterned structure which represents a grid having at least one cycle formed of at least two locally adjacent elements having different optical properties in respect of incident radiation, the structure having a plurality of features defined by a certain process of its manufacturing, the method comprising the steps of:a) providing an optical model, which is based on at least some of said features of the structure and on relation between wavelength range of the incident radiation to be used for measurements and pitch of the structure under measurements, and is capable of determining theoretical data representative of photometric intensities of light components of different wavelengths specularly reflected from the structure and of calculating said at least one desired parameter of the structure; b) locating a measurement area for applying thereto spectrophotometric measurements, wherein said measurement area is a grid cycles containing area and is substantially larger than a surface area of the structure defined by one grid cycle; c) applying the spectrophotometric measurements to said measurement area by illuminating it with incident radiation of a preset substantially wide wavelength range, detecting light component substantially specularly reflected from the measurement area, and obtaining measured data representative of photometric intensities of each wavelength within said wavelength range; d) analyzing the measured data and the theoretical data and optimizing said optical model until said theoretical data satisfies a predetermined condition; and e) upon detecting that the predetermined condition is satisfied, calculating said at least one parameter of the structure.