A novel method for measuring the thickness of lubricant coated on magnetic recording media using time-of-flight secondary ion mass spectroscopy (TOF-SIMS) is proposed. This method employs a pulsed primary ion beam to uniformly etch the lubricant layer down to the underlying carbon overcoat layer. The lubricant thickness is determined by detecting the etching time taken for the lubricant backbone fragments CF2O and C2F4O to converge or alternatively by monitoring the maximum position of the depth profile of CH fragment. The film thickness determined by this new method showed good linearity across a wide range and correlated well with current available techniques such as Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. (C) 2002 Elsevier Science B.V. All rights reserved.