Development of a Micro Reconfigurable Ultra-Precision Interferometer

Nowadays, in pace with the development of semiconductor, micro-electronic and biological industries, many micro/nano manufacturing, positioning and metrology depend on the technologies of ultra-precision sensor. However, to achieve large metrology range and high resolution is not only an expensive, bulky but an environmental dependent task. As a result, the main contribution of this thesis is to solve the above paradox and develop a low cost, high accuracy, large metrology scale, compact and free of environmental effect sensor scheme.
Laser interferometers provide the reliability of the accuracy of the instruments in industrial use, but the size and cost make them almost impossible to be embedded into the system as sensor. Based on the same metrology principle, our research makes efforts in minimizing and simplifying the interferometer as a practically useful sensor in industrial use.
To achieve the above-mentioned goal, we present a versatile interferometric module as the core of our sensor. By applying the polarizing theory and four-detector-array, the performance of the sensor can be optimized. It can be reconfiguring to a number of metrology way and measurement range by adopting different sets of plane mirrors. This research also presents a general scheme of signal processing by mixing a hardware circuit and a software algorithm, proceeding pre-correction, real-time compensation, wave count and interpolation of the metrology signal.
The whole sensor scheme can rapidly reconfigured into polarizing Michelson interferometer, pitch-yaw angle interferometer, anti-deflection angle interferometer, linear diffraction grating interferometer and planar diffraction grating interferometer. The accuracy and the measurable range of the three displacement sensor are experimentally testified to be better than 27 nanometers and 25 millimeters in two directions. The angular accuracy of the angle sensors are 0.25 arcsec in static measurement and 1 arcsec in large linear motion measurement.