X-ray photoelectron spectroscopy (XPS) using fullerene (C-60) cluster ion bombardment was applied to films of a fluorinated block copolymer. Spectra so obtained were essentially different from those using Ar ion beam. Structure in the surface region with the depth down to 60 nm drawn on the basis of XPS with C-60 beam was essentially the same as the one drawn by the result using dynamic secondary ion mass spectrometry, which is a well-established method for the depth analysis of polymers. This implies that XPS using C-60 beam enables one to gain access to the depth analysis of structure in polymer. films with the depth range over the analytical depth of conventional XPS, that is, three times inelastic mean-free path of photoelectrons. (c) 2008 Elsevier B.V. All rights reserved.