Vibration compensation of wavelength scanning interferometer for in-process surface inspection

A vibration stabilized Wavelength Scanning Interferometer (WSI) is developed for online or in-process measurement purposes. This paper describes the vibration compensation part of the WSI system. The vibration compensation is provided by multiplexing a reference interferometer with the main WSI
interferometer. The reference interferometer has a different light source and wavelength from the WSI interferometer but both are sharing common optical path. The reference interferometer serves as a phase-compensating mechanism to eliminate the effects of environmental noise. A structured surface measurement of a semiconductor daughterboard, under mechanical disturbance, is presented. The measurement results showed that the system can withstand environmental noise.