title: Fast surface measurement using wavelength scanning interferometry with compensation of environmental noise.
abstract: We introduce a new optical interferometry system for fast areal surface measurement of microscale and nanoscale surfaces that are immune to environmental noise. Wavelength scanning interferometry together with an acousto-optic tunable filtering technique is used to measure surfaces with large step heights. An active servo control system serves as a phase-compensating mechanism to eliminate the effects of environmental noise. The system can be used for online or in-process measurement on a shop floor. Measurement results from two step height standard samples and a structured surface of a semiconductor daughterboard are presented. In comparison with standard step height specimens, the system achieved nanometer measurement accuracy. The measurement results of the semiconductor daughterboard, under mechanical disturbance, showed that the system can withstand environmental noise.
authors.affiliation: Centre for Precision Technologies, School of Computing and Engineering,University of Huddersfield, Huddersfield HD1 3DH, United Kingdom. x.jiang@hud.ac.uk
authors.forename: Xiangqian
authors.initials: X
authors.lastname: Jiang
authors.forename: Kaiwei
authors.initials: K
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Hussam
authors.initials: H
authors.lastname: Muhamedsalih