CFX (X=1-3) radicals were found to be generated from fluorocarbon films deposited on the reactor wall when the films are irradiated with plasmas. In this process, the fluorocarbon films were first formed on the reactor wall by electron cyclotron resonance (ECR) etching plasmas employing C4F8 and C4F8/H-2 gases, and subsequently irradiated with an ECR-Ar plasma. CFX radical densities were measured during the Ar plasma by infrared diode laser absorption spectroscopy. CF3 radical density in the Ar plasma was estimated to be the same order as that in the C4F8 plasma. the fluorocarbon films deposited on the reactor wall were investigated by x-ray photoelectron spectroscopy. These results will offer valuable information for the production mechanism of CFX radicals in the etching process employing fluorocarbon gases.