Apparatus and method for generating profiles of constituents of chemical mixtures

摘要

An apparatus, system and method are described for determining profiles of the absolute or relative concentrations of N constituent chemical components of a chemical mixture over a group of samples. For each sample a plurality of sets of concentrations is determined wherein each set has substantially the same error for corresponding to the absorption spectra measured for the composite sample. A plurality of samples of the chemical mixture are generated, for example, by removing parts of a surface sequentially. From amongst the plurality of sets of absolute or relative concentrations over the plurality of samples, a path of highest probability is determined from which profiles of each of the chemical components can be determined. The invention is applied to generating profiles of chemical constituents as material is received from a surface of a semiconductor chip to generate profiles as a function of depth into the sample.