微機械邏輯閘的絕緣製程設計及實現

Abstract

可攜式裝置(mobile devices)的盛行，代表續航能力的要求提高，因此半導體元件一直存在的漏電流及偏壓電流功率損耗問題也逐漸被重視，相關的研究也陸續提出，而微波微機械開關(RF MEMS Switch)的研究即是其中之一。微波微機械開關具有低耗能(low power consumption)、高絕緣性(high isolation )、低耗損(low insertion loss)、可批次製造等優點，然而其僅具“開╱關”功能，應用上易受局限。因此本篇論文研發具邏輯功能之微機械開關，此元件結合微機械開關的優點與IC邏輯閘的功能，冀望能藉由與傳統IC邏輯閘之輸出輸入的相匹配，進而直接取代傳統邏輯線路中部分之IC邏輯閘。我們預期此元件將比微波微機械開關更容易且廣泛的被使用。 在文獻[1]中，先前的研究者提出了構想中微機械邏輯閘的設計雛型，並以軟體模擬驗證其可行性，最後再以微機械薄膜製程的方式嘗試製造此元件，雖然未完成元件的製作，但由其製作經驗，歸納出失敗的可能原因。 本篇論文針對微機械邏輯閘[1]製程中所遭遇到的問題，提出兩種製程改善的方法，修正其缺失之處，並成功的以微機械薄膜製程的技術來完成微機械邏輯閘的製作。在完成元件製作後，進行元件靜態和動態特性的量測，包括元件尺寸、邏輯功能、暫態響應、頻率響應等等，並且和數學分析的結果作比較；暫態響應的誤差平均為6.3％，頻率響應平均誤差為7.95％，並以顯微鏡觀察的方式確認了元件具有預期的邏輯功能。

The problem of “leakage current” and bias current consumption, existed in semiconductor components, is getting more and more attention with widely spreading of mobile devices. RF MEMS switch has been developed as one of the major means to solve this problem. It has the advantages of high isolation, the ability to integrate with other solid-state devices, and so on. However, it only equips with on/off function which hampers its use. In our research group, we proposed MEMS logic gates designs which combine the advantages of MEMS switches and IC logic gates. We expect a great potential for this device. In previous research [1], the researcher proposed a prototype design of MEMS logic gate and a surface micromachining process for making it. He verified his design concepts with related software. Unfortunately, he did not get to finish the fabrication due to fabrication process issues. He concluded his research by pointing out some problematic fabrication steps. In this thesis, we proposed two fabrication processes to fix the problems pointed out in research [1], and we successfully fabricated the device in the end. We also did various experiments to characterize this device. As compared to simulation results, the experimental data of transient response and frequency response deviated from simulated values roughly at 6.3% and 7.95％, respectively. We also verified its logic function by observation through microscopes.