微型可重構式超精密光學干涉儀之研製

Abstract

隨著半導體產業、微電子產業、微生物產業等小尺度工程的發展，許多奈米級的加工、定位、量測系統都有賴於超精密的感測器技術；然而，想要同時達到大量程與高解析度的代價不僅昂貴、體積龐大而且容易受到環境影響。因此，本研究主旨為解決上述問題並研發低成本、高精度、大量程、工藝技術簡單且不受環境影響的感測器。 在工業上，雷射干涉儀的使用加強了系統精度的可靠性，但雷射干涉儀受限於價格和體積，並不適合嵌入一般儀器中做為感測器使用。本研究基於同樣的干涉原理，將精密干涉儀微小化並簡易化成可在工程上實用的感測器，並加強安裝時的寬鬆性，不造成使用上的障礙。 為了達到上述的目的，本研究提出一種多工式干涉模組(versatile interferometric module, VIM)做為感測器的核心元件，利用偏極化光學理論和四通道光感測器陣列來優化系統的性能。搭配上不同的平面鏡並偏折光路即可實現許多不同的量測方式及量測範圍。在訊號處理方面，提出了硬體電路和軟體演算法，進行前級訊號修正、後級訊號即時處理、訊號計數、細分割等動作，為一通用式的訊號解析模組。 整套感測器系統可快速重構成麥克森干涉儀(PMI)、雙角度干涉儀(PYAI)、抗偏擺式角度干涉儀(ADAI)、線性光柵尺(LDGI)或平面光柵尺(PDGI)。各種位移感測器的精度經實驗驗證後都優於27 nm，量測範圍最高可以達到兩個方向各50 mm；角度感測器在定距離量測時精度為0.25 arcsec，當量測鏡進行長距離之線性運動時，量測精度也都優於1 arcsec。

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.