CCD camera-based analysis of thin film growth in industrial PACVD processes

In this paper we present a method for the characterization of (semi-transparent) thin film growth during PACVD processes (plasma assisted chemical vapour deposition), based on analysis of thermal radiation by means of nearinfrared imaging. Due to interference effects during thin film growth, characteristic emissivity signal variations can be observed which allow very detailed spatio-temporal analysis of growth characteristics (e.g. relative growth rates). We use a standard CCD camera with a near-infrared band-pass filter (center wavelength 1030 nm, FWHM 10nm) as a thermal imaging device. The spectral sensitivity of a Si-CCD sensor at 1μm is sufficient to allow the imaging of thermal radiation at temperatures above approx. 400 C, whereas light emissions from plasma discharges (which mainly occur in the visible range of the electromagnetic spectrum) barely affect the image formation.