Patent ID: 6433541
Filing Date: 2002-08-13
Classification: G01N

Abstract:
A method of obtaining information in-situ regarding a film of a sample using an eddy probe dung a process for removing the film, the eddy probe having first and second sensing coils, the method comprising:(a) applying an AC voltage to the first and second sensing coils of the eddy probe; (b) measuring one or more first signals in the first sensing coil of the eddy probe when the sensing coil is positioned proximate the film of the sample; (c) measuring one or more second signals in the second sensing coil of the eddy probe when the sensing coil is positioned proximate to a reference material having a fixed composition and/or distance from the second sensing coil; (d) calibrating the first signals based on the second signals so that undesired gain and/or phase changes within Me first sills are corrected; and (e) deter a property value of the turn based on the calibrated first signals, wherein the measuring one or more first signals and the measuring one or more second signals are performed substantially simultaneously.