Time-varying axial magnetic field of approximately 10-15 G is added to an inductively coupled plasma. High aspect ratio deep-sub-micron contact holes in borophosphosilicate glass have been etched by C4F8/Ar plasma. In order to correlate etched profile with etching conditions, deposition of polymeric precursors in the etching process is monitored. By means of the appearance mass spectroscopy, the distributions of CFx+ ions and CFx radicals are measured as a function of the frequency of axial magnetic field. The axial magnetic field is found to influence the densities of fluorocarbon ions (CFx+; x = 1-3), F and CFx radicals. X-ray photoelectron spectroscopy shows that fluorocarbon polymer on oxide surface strongly varies with the frequency of axial magnetic field. 0.2 mum diameter contact holes with aspect ratio of 10 are successfully fabricated in this system. (C) 2003 Elsevier Science B.V. All rights reserved.