利用垂直梳狀致動器驅動之抬起式為掃描鏡之設計、製作及組裝

Abstract

近年來隨著半導體產業的發展，微機電製程技術有許多重大的發展。微光機電技術(Micro-Opto-Electro-Mechanical System)提供了一個實現微型光學系統的好方法。在自由空間的光學平台應用上，三維抬起式微結構的角色也更加重要。 我們的最終目標為設計一微光學資訊儲存平台，採用SOI (Silicon on Insulator)基板上的單晶矽作為鏡面結構，因為它的低應力可以避免其他材料製作時可能發生的翹曲現象。SU-8光阻可用簡單微影製程製作高深寬比結構，所以使用它來製作結構層。 本實驗室之前已提出利用簡單下壓動作進行任意角度斜面鏡的組裝，成功驗證了不同角度的組裝，並將135˚斜面鏡應用在微光學讀取頭的架構。本論文提出一構想，在以下壓方法的組裝基礎上，在斜面鏡上製作垂直梳狀致動的微掃描鏡，並將之應用在微光學讀取頭的架構當中實現循軌伺服的功能。 本論文已成功量測到組裝前靜態與動態掃描特性。具有直線形扭力彈簧的微掃描鏡在110V的直流電壓驅動下有0.57˚的機械掃描角。具有彎曲式彈簧的微掃描鏡在5V直流電壓±5V交流電壓的驅動下，在共振頻率下具有0.8˚的光學掃描角。由於梳指間隙受限於曝光機的誤差約±2μm，所以限制了微掃描鏡的效能，本論文也提出了一新式的製程，可將梳指間隙縮小至3μm，提升效能。

Recently, Micro Electro Mechanical System (MEMS) technology has many important developments with the rapid progress in the semiconductor industry. Micro-Opto-Electro-Mechanical System (MOEMS) technology provides a method to realize miniaturized optical systems. Three-dimensional (3-D) flip-up MEMS structures are important components in applications such as free-space optical bench. In this thesis, low-stress silicon on insulator (SOI) wafers are used to avoid stress-induced curvature for optical applications. SU-8 can be processed by simple lithography with high aspect ratio, making it suitable for another structural layer. In our previous study, flip-up structures with arbitrary angles were assembled using a simple push operation. The design and assembly of 135˚ mirrors were verified and used in the proposed optical pickup head. A flip-up micro scanning mirrors assembled by the simple push operation were proposed in this thesis. It can be integrated on the proposed optical pickup head as the tracking servo actuator. The characteristics of the micro scanning mirror before assembly were measured. The maximum static scanning angle of the beam type mirror was 0.57˚ with 110 V applied voltage. The maximum dynamic scanning angle of the meander type mirror was 0.80˚ with ±5 V sinusoidal and 5 V DC applied voltage at 413.6 Hz. The performance was strongly related to the finger gaps. The large finger gaps were limited by the accuracy of the aligner. The vertical comb fingers fabricated by the new fabrication process are proposed to improve the performance.