Surface interactions of CF2 radicals during deposition of amorphous fluorocarbon films from CHF3 plasmas

Surface reactivities for CF2 radicals formed in a CHF3 plasma molecular bea m are measured during film deposition on a variety of substrates. The imagi ng of radicals interacting with surfaces (IRIS) technique was used to colle ct spatially resolved laser-induced fluorescence (LIF) images of CF2 radica ls interacting with SiO2, Si3N4, Si, 304 stainless steel, and system 8 phot oresist substrates. Films deposited during IRIS experiments were characteri zed using x-ray photoelectron spectroscopy and Fourier transform infrared s pectroscopy and were found to be nearly identical in composition on all sub strates. Simulation of LIF cross-sectional data shows high scattering coeff icients for CF2 radicals on all substrates. These extremely large scatterin g coefficients (>1.0) indicate that CF2 molecules are generated through pla sma interactions with the substrate. Possible CF, surface generation mechan isms an discussed, with consideration of CF and ion bombardment contributio ns to the generation of CF2. (C) 1998 American Institute of Physics. [S0021 -8979(98)07721-4].