Behaviors of gas species in electron cyclotron resonance (ECR) plasmas employing low global warming potential fluorocarbon gases of hexafluorobutadiene (C4F6) and hexafluoropropene (C3F6) with unsaturated carbon bonds together with the conventional octafluorocyclobutane (c-C4F8) are investigated. The spatial distributions of the absolute CF and CF2 radical densities are measured by combining the single-path infrared diode laser absorption spectroscopy and laser-induced fluorescence techniques. CF2 radicals have hollow-type distributions at all conditions in the ECR plasma reactor. However, the spatial distribution of the CF radical density differs greatly from that of the CF2 radical density. Behaviors of carbon atoms measured by vacuum ultraviolet absorption spectroscopy disagree with those of CF and CF2 radical densities. The behaviors of ion and fluorine species and the gas pressure in the plasma have been also evaluated. Fluorocarbon films with low dielectric constant of about 3.0 are deposited at a high rate of 600 nm/min at high microwave powers in C3F6 and C4F6 plasmas. The distribution of deposition rates of the film on the 8 in. Si substrate shows hill-type distributions, which are quite different from the spatial distribution- - s of CF and CF2 radical densities. Therefore, CF and CF2 radicals do not directly contribute greatly to the growth of fluorocarbon films in these plasmas. The behaviors of C atom densities indicate the similar tendency to those of deposition rates of films. On the basis of systematically measured results of species in the plasma and film deposition rate on Si wafer, it is clarified that the C atom and polymeric species contribute dominantly to the formation of films at a high rate in low-pressure and high-density fluorocarbon plasmas. © 2001 American Vacuum Society.