Non-contact charge-voltage method for dielectric characterization on small test areas of IC product wafers

We present an electric characterization method for monitoring dielectrics on miniature 50 μm×70 μm scribe line test sites of semiconductor IC product wafers. The method is an extension to micro-scale of the corona–Kelvin metrology used for much larger sites of about 5 mm in diameter. A miniaturization of the corona charging and of the Kelvin probe is accomplished without a sacrifice in precision or repeatability. The apparatus incorporates a machine vision system for identification of test sites. The micro-testing is demonstrated using advanced gate dielectrics and key electrical parameters, i.e., dielectric capacitance, leakage, dielectric charge and flatband voltage. Monitoring is non-contact and it adds no contaminants or particulates. Therefore, after measurement, the product wafer can be returned to the fab-line for further processing.