The neutral active products extracted from a microwave discharge in CF4/He were analyzed by mass spectrometry. Free radical species such as CHF2,CF2, and CF3 were detected and analyzed for the first time using the Li+ ion attachment mass spectrometry technique. We examined the effects of varying the MW power and the feed gas composition on the production of an intense flow source of CHF2, CF2, and CF3 radicals as well as many other products. A radical chain reaction is postulated as the mechanism for the formation of the observed polymeric products. (c) 2005 Elsevier B.V. All rights reserved.