Patent ID: 7173418

Claim:
A method of determining a first thickness of a first conductive layer formed of a first conductive material on a target substrate, said target substrate further having a second conductive layer formed of a second conductive material different from said first conductive material, comprising: positioning a first eddy current sensor at a given position relative to said target substrate, said first eddy current sensor being in a spaced-apart relationship with respect to said target substrate when positioned at said given position; measuring, using said first eddy current sensor while said first eddy current sensor is positioned at said given position, a first set of electrical responses that includes at least one of a first voltage measurement and a first current measurement, said measuring said first set of electrical responses being performed at a first target substrate temperature; measuring, using said first eddy current sensor while said first eddy current sensor is positioned at said given position, a second set of electrical responses that includes at least one of a second voltage measurement and a second current measurement, said measuring said second set of electrical responses being performed at a second target substrate temperature different from said first target substrate temperature; calculating a third set of electrical responses using at least said first set of electrical responses and said second set of electrical responses, and a first temperature coefficient of said first conductive layer, said third set of electrical responses representing responses substantially attributable to said first conductive layer; and determining said first thickness from said third set of electrical responses.