Abstract
Flying height of hard disk drives was measured based on Phase Comparison Michelson Interferometry (PCMI), which utilizes the phase comparison of two interference fringe patterns formed respectively on the inner surface of a glass disk and the air bearing surface of a flying head slider through the glass disk. To suppress Interference noise and to further enhance measurement accuracy, low coherent white light was adopted as an Illuminating source to replace high coherent laser. The measured results show that the application of white light illumination effectively improves interference fringe patterns, and greatly minimizes the measurement error of extracting the ridgeline in comparison with a laser. Sub-10nm flying height was measured with high accuracy and good repeatability.
