Real-Time Observation of Molecularly Thin Lubricant Films on Head Sliders Using Rotating-Compensator-Based Ellipsometric Microscopy

Lubricant transfer or pickup from a disk to a head slider is a crucial issue in designing the head-disk interfaces of hard disk drives (HDDs). A method based on ellipsometric microscopy is presented for observing thin lubricant film on a head slider in real time. The use of rotating-compensator ellipsometry (RCE) results in one order of magnitude higher temporal resolution (0.6 frames/s) and several times higher thickness resolution (0.2 nm) compared to null-ellipsometry-based microscopy, which was recently proposed. RCE-based ellipsometric microscopy will be useful in clarifying the mechanism of lubricant pickup for higher density HDDs.