應用於下世代生醫檢測與邏輯之互補式金屬氧化物半導體整合微/奈米流道細胞/電化學感測 及互補式場效電晶體

Abstract

本論文包含三個部分：用於細胞檢測的CMOS嵌入式微流道系統、用於電化學感測的CMOS晶片上電極開發以及CFET元件的製作。首先，我們提出了一種新穎的CMOS嵌入式微流道平台，該平台具有晶片上阻抗感測電極和三維微/奈流體學，適用於下一代POC診斷設備。該平台採用單步驟後CMOS濕刻蝕刻製程，透過去除CMOS後端製程走線（BEOL），由金屬來形成中空流體通道。通過提高水力壓力來優化蝕刻過程，從而將蝕刻速率提高了10倍。為了研究各種流體通道的可行性，我們設計了多種具有不同功能的通道幾何形狀，對應日益增長的微流道技術與元件。為了晶片上電極進行阻抗感測，我們探索了各種策略，並提出了“通孔”電極，在保持檢測能力的同時亦維持其完整性。我們還研究了平台的長期穩定性，並展示了使用不同濃度離子溶液進行阻抗感測的有效性。此外，我們還設計了一個跨阻放大器，使用串接電流再利用放大器作為類比前端電路，製作了我們提出的高度CMOS整合的微流道系統的原型。其次，我們展示了用於電化學感測的CMOS片上電極的開發。我們採用化學鍍膜和蒸鍍沉積的過程在鋁墊層上製作金層。通過這樣的技術開發，我們成功地將微電極陣列與CMOS晶片整合。為了驗證我們感測電極的功能，我們使用卡那霉素之適體進行分子感測。結果與商業電極的結果相似，因此可證明其功能。最後，我們介紹了一種新的製程技術，用於實現CFET結構。我們採用薄膜轉移技術來製作堆疊通道結構，無需進行複雜的磊晶生長和晶圓鍵合。透過使用氦離子束微影技術，我們成功地將元件的關鍵尺寸縮小到50奈米以下。

This thesis contains three parts: a CMOS-embedded microfluidics system for cell detection, CMOS-integrated on-chip electrode development for electrochemical sensing, and the fabrication of a CFET device.To begin with, we present a novel CMOS-embedded microfluidics platform that features on-chip impedance-sensing electrodes, and 3D micro/nanofluidics suitable for next-generation point-of-care (POC) diagnostic devices. The platform uses a single-step post-CMOS wet-etching process to create hollow fluidic channels by removing CMOS back-end-of-line (BEOL) routing metals. The etching process is optimized by improving the etching rate by 10× through hydraulic pressure. To investigate the feasibility of a variety of fluidic channels, we design several channel geometries of different functions, corresponding to more and more emerging microfluidics techniques. To integrate on-chip electrodes for impedance sensing, we explore various strategies and present "via" electrodes that maintain their integrity in the etching process while preserving detection sensitivity. We also investigate the long-term reliability of the platform and demonstrate the efficacy of impedance sensing using ionic solutions of varying strengths. We also design a transimpedance amplifier employing a cascode current-reuse amplifier as an analog front-end circuit to make the prototype of our proposed highly CMOS-integrated microfluidics system.Secondly, we demonstrate the development of CMOS on-chip electrodes for electrochemical sensing. We adopt the process of both ENIG and evaporator deposition to make a gold layer onto the aluminum pad layer. With such process development, we successfully integrate a microelectrode array with a CMOS chip. To verify the functionality of our sensing electrodes, we use kanamycin aptamer to conduct molecular sensing. The results are consistent with the data from commercial electrodes.In the last, we introduce a novel fabrication technique to realize the CFET architecture. We use membrane transfer techniques to make the stacked channel structure without complex epitaxial growth and wafer bonding. By using helium ion beam lithography, we successfully shrink the device’s critical size to below 50nm.