本研究期待設計出一套具有最大電容特性及最佳靈敏度的指叉式電容生物感測器之範本。本研究利用先進設計系統(Advanced Design System)軟體進行二維電場模擬及使用田口實驗設計分析法，可獲得指叉式電容感測器之最佳電極幾何參數設計和各電極參數與電容效應之比重關係。針對指叉式電容生物感測器，本研究所設計出的最佳電極之各幾何參數，分別為電極寬度 = 1200 μm、電極間距 = 0.01 μm、電極厚度 = 500 μm以及電極交叉長度 = 10000 μm，其整體電容效應遠大於一般文獻上之指叉式電容生物感測器，約為795.17倍；各電極參數與電容效應之比重關係為電極寬度(31.65%) > 電極間距(26.154%) > 電極厚度(23.154%) > 電極交叉長度(19.039%)。考慮以現今製程技術實現之容易度，將電極寬度與電極間距設定為一般文獻常用值10 μm，而電極厚度及電極交叉長度仍遵循本研又究所得到的最佳參數設計。在設計上遷就製程技術現實所得到的電容效應雖然只是採用最佳電極參數尺寸之設計的5.53分之一，但卻是未採用最佳化設計者的142.96倍。對於生物待測物(例如DNA cylinder、Protein G及MDA231 Cell等)的靈敏度方面，遷就製程技術所設計出的感測器與最佳化設計的表現相近。故本研究的結論建議使用遷就現有製程之最佳電極參數尺寸來設計電容性生物感測器，以利於使用現今製程來實現並提高偵測的靈敏度。 The goal of this research is to develop an interdigitated capacitive biosensor with maximum capacitive response and highest sensitivity. This research concentrated on two-dimensional electric-filed simulation using ADS (Advanced Design System) to analyze and understand the capacitive response of interdigitated biosensors. Furthermore, Taguchi method was employed to find the optimal electrode geometric parameters. The optimal geometric parameters of interdigitated capacitive biosensor thus determined were: electrode width = 1200 μm, electrode spacing = 0.01 μm, electrode thickness = 500 μm, and overlapping length = 10000 μm. The capacitance of this optimal design was 795.17 times as big as that of an interdigitated capacitive biosensor with ordinary geometric parameters. The capacitance of an interdigitated biosensor is determined collectively by its geometric parameters. According to the results by Taguchi method, the relevant parameters and their weights of influences were: electrode width (31.65%), electrode spacing (26.154%), electrode thickness (23.154%), and overlapping length (19.039%). A suboptimal design was proposed to meet the current process limitation. The electrode width and spacing were both changed to 10um, whereas the electrode thickness and overlapping length followed the optimal geometric design. The resultant capacitance was reduced to 1/5.53 times as big as that of the optimal design. Nevertheless, it was still 142.96 times as big as that with the ordinary geometric parameters. For detection of DNA, protein, cell, et. al., by biosensors of suboptimal geometry design, the sensitivity doubled that of the ordinary design and was commensurate to that of the optimal design. Hence, the suboptimal design represents a good choice for capacitive biosensors to attain high sensitivity under current process limitation.
