Patent ID: 7268876

Claim:
A method of fabricating and characterizing the outermost material of an article which is manufactured by the deposition or removal of material, to or from, a process substrate, without explicit knowledge of any previously deposited underlying layers, said method comprising a procedure which comprises steps a, a′, b and c, said steps a, a′, b and c being: a) providing a material deposition or removal chamber and an ellipsometer system configured with respect thereto so as to, in use, cause a beam of polarized electromagnetic radiation to impinge upon a process substrate therewithin during a procedure in which material deposition or removal upon said process substrate is caused to occur over a period of time; a′) obtaining ellipsometric data during material deposition or removal upon said process substrate at three distinct times (t 1 ), (t 2 ), and (t 3 ); b) using a system of analytic equations which are derived from the exact Fresnel equations that describe the interaction of electromagnetic radiation with a layered material system, such analytic equations not requiring any knowledge of the underlying layer structure previously deposited on the sample, calculating ellipsometric data at time (t 3 ), using the ellipsometric data acquired at times (t 1 ) and (t 2 ), and a parameterized optical model for the outermost material deposition or removal that occurs between (t 1 ) and (t 3 ), and (t 2 ) and (t 3 ); c) determining the optical model parameters which characterize the outermost layer(s) by minimizing the difference between the ellipsometric data calculated at time (t 3 ) by the analytical equations in b) and the ellipsometric data measured at time (t 3 ), using a minimization algorithm; and d) practicing said procedure steps a, a′, b and c to the end that said article is manufactured and said outermost material thereof is characterized.