KLA Corporation
Micro-Four-Point Metrology of Joule-Heating-Induced Modulation of Test Sample Properties

Abstract:

A method of obtaining a physical property of a test sample, comprising a conductive or semi-conductive material (line/area/volume), by performing electric measurements using a multi-terminal microprobe. Periodic Joule heating within the test sample is induced by passing an ac current across a first pair of probe terminals electrically connected to the test sample, measuring the voltage at one and three times the power supply frequency of the current-conducting terminals across a second pair of probe terminals electrically connected to the test sample, and calculating the temperature-modulated property(ies) of the test sample as a function of the voltage measurements at said frequencies. A value proportional to the Temperature Coefficient of Resistivity (TCR), an Electrical Critical Dimension (ECD), or the true resistivity of the test sample at the ambient experimental temperature by subtracting a measurable TCR offset from the apparent (heating-affected) resistivity of the test sample can be determined.