Advanced designs of specialty films have led to the need for better measurement tools to confirm product quality. One of the most critical parameters of specialty films is thickness measurement. Increasing demands for improved precision and repeatability require the ability to measure films as thin as 1 nm and as thick as 1 mm or more. Although several commercial devices and techniques based on ellipsometry, spectrophotometry, eddy current, and ultrasound exist, and have adequately addressed the needs of layer thickness measurements in the past, they are not capable of such precision. In this paper, we describe a new technique for measuring the thickness and constant of dielectrics for ultra thin, thin and thick films. This technique uses Corona Discharges as a source of ions and non-contact Surface Potential measurements. Corona-assisted Surface Potential measurements are excellent tool in measuring film thicknesses as thin as 1 nm and as thick as 1 mm. Experimental results show that Surface Potential variations are directly related to the thickness and to the dielectric constant of contaminants or oxides. A model fitting with these results is proposed and discussed.
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