| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 103 === According to the 2014 annual report of Health Promotion Administration (Ministry of Health and Welfare, Taiwan), the hepatocellular carcinoma (HCC) has become the second major cancer killer in Taiwan. Usually, the concentration of alpha fetoprotein (AFP) in human serum can be detected by various commercial sensing equipment (&;gt; 40×30×10 cm3) and be used for the initial stage diagnosis of HCC. Various flexural plate-wave (FPW) micro biosensors and related bio-sensing microsystems (25×10×5 cm3) have been developed for POCT (Point-of-Care Testing) applications in our previous researches. However, the conventional FPW devices have two major disadvantages of high insertion loss (&;gt; 40 dB) and low fabrication yield (&;lt; 10%) which will limited their commercialization.
To improve effectively the insertion loss and fabrication yield of FPW device, a small-size interdigital transducer with circular-arc geometry design, two different rate of silicon anisotropic etching process and a high C-axis ZnO piezoelectric thin-film deposition process are developed in this thesis. The main fabrication steps of the proposed FPW based on AFP-biosensor including seven thin-film depositions and five photolithography processes. Two major technologies used in this work are micro-electro-mechanical systems (MEMS) technology and cystamine based self-assembly monolayer (SAM) nanotechnology.
The implemented FPW device with dimension only about 0.7×0.9 cm2 and the thickness of suspended silicon plate can be accurately controlled to 20 μm. Under the optimized conditions, a very low insertion loss (-36.04 dB), very high fabrication yield (64.81%) and high mass sensitivity (70.06 cm2/g) can be obtained. Furthermore, the proposed FPW based AFP-biosensor demonstrated a very low detection limit (5 ng/mL) and high mass-sensing linearity (0.9304).
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