微壓電陀螺儀設計、分析與製作

Abstract

本論文提出一平面設計之微壓電陀螺儀，此壓電陀螺儀在放置於待測物體上和其驅動及感測模態皆設計在同一平面上，藉此去縮減音叉型和Ｈ型陀螺儀在固定於待測物體上所占去的垂直體積。而驅動及感測材料採用壓電材料，正是看中壓電材料結構簡單、輸出力大的優點去彌補微陀螺儀常見的因質量過小而造成響應訊號之不足的問題。 在ANSYS軟體的模擬下，此論文提出的壓電陀螺儀設計驅動模態和感測模態共振頻率分別在4654赫茲和 4674 赫茲；其操作頻率為 4664 赫茲。而在角速度和輸出訊號間有一線性關係，並有mini volt 數量級的輸出。對科氏力的估算也有在此研究中提出，並且找出角速度、科氏力、位移量及訊號輸出間的關係。 文末提出兩種製程對於PZT在Si3N4上沒有辦法結晶成功，以及非全Pt 表面上多層沉積結晶的不可行性進行了驗證，也提出製程替代方案，亦證實了製程中因欲定義SiO2 而在PZT無保護層的情況下使用濕式蝕刻程序的不可行性及提供相關實驗數據，其他實驗相關數據，例如：PZT蝕刻配方，蝕刻速率，每層沉積厚度...等也都有提供，最後更提出PZT壓電材料裝置微機電製程流程方案。

This study proposes a piezoelectric gyroscope designed in a flat shape. The driving mode and detecting mode are on the same plane. Because of its flat shape, it will not occupy so much volume as the traditional fork-shaped and H-shaped gyroscopes in vertical space when it is installed on the target object. In addition, traditional gyroscopes face the problem of the detecting mass being too small, which causes output signals to be weak. Therefore, compared to traditional gyroscopes, using piezoelectric material for sensing and actuating would make the structure simpler and the signals of response will be much stronger. In ANSYS simulations, the driving mode resonant frequency and sensing mode frequency are located individual at 4654 Hz and 4674 Hz. The operating frequency of this gyroscope is 4664 Hz. The relation between angular velocity and output signals is a linear tendency, and the signals were at the mini volt level. Coriolis force derivation is also mentioned in this study, and the relationships among angular velocity, Coriolis force, displacement and output electric potential are discussed. In the last chapter, it is shown that the first fabrication process proved the unfeasibility of PZT multi-layer deposition on an incomplete Platinum layer surface and directly wet etches SiO2 without any protecting mask on the PZT layer. The chapter includes data about the fabrication process, i.e. PZT etchant recipe, wet etching rate, PZT deposition thickness per layer etc. are provided too. At the end of the chapter, based on the unsuccessful fabrications, an improved fabrication process for PZT related device is proposed.