- 學位論文
雷利式表面聲波應用於微流控晶片分離微奈米粒子與模擬分析
Nano-particle Separation and Sorting by using Rayleigh Surface Acoustic Wave based on Microfluidic Chip and Simulation Analysis
摘要
本研究藉由壓電材料鈮酸鋰產生雷利式表面聲波(Rayleigh Surface Acoustic Wave, R-SAW)結合微流體控制技術進行微奈米粒子的分離，並且提出具反射閘極的指叉電極結構之表面聲波分離晶片及其有限元素數值模型分析。將模擬的結果與量測、實驗操作的結果進行討論與比較，建立出表面聲波分離晶片其頻率響應與微奈米粒子之聲波力運動響應。 有限元素分析法針對特徵頻率響應、頻域分析與時間相依的分析，設計不同的指叉電極結構，模擬表面聲波模型之散射參數與阻抗分析，將模擬結果與網路分析儀實際測量晶片參數進行比較，其量測之共振頻率與模擬結果的中心頻率吻合，且在時間相依分析下晶片表面透過指叉電極的時變訊號而激發出表面聲波。除此之外，使用Matlab數值分析建立微奈米粒子在微流道間的粒子運動軌跡亦與實驗結果相近。 研究中採用4吋128°YX-LiNbO3鈮酸鋰晶圓使用半導體製程的技術在基板上製作指叉電極與微機電技術翻模製造微流道完成表面聲波分離晶片。在操作頻率為12.8MHz施加峰值為12.5伏特雙埠時變電場的訊號分離10μm與3μm的奈米粒子，其分離率達95%。提出在高頻的操作下具反射閘極的結構有更低的插入損失，在操作頻率為40MHz施加峰值為21伏特的訊號分離200nm與500nm的奈米粒子，以粒徑分析儀(Dynamic Light Scattering, DLS)做樣品分析其分離率高達93%。 在模擬晶片頻域分析下尋找最佳的幾何設計並且在時域分析具駐波效應，而駐波形成的壓力節點在微流道的模擬下成功模擬出粒子移動之現象，與實驗中有高度的吻合。透過網路分析儀分析晶片的散射參數進而提升晶片的分離效率與最佳化設計。 表面聲波作為分離的技術，單純利用粒子的物理特性不同達成分離，具有結構簡單、成本低、高通量的特性。其優點在於分離速率快、純度高且為非接觸式分離，在生物醫學領域可以保護細胞免於結構或是分子的改變，其技術應用甚廣於各種領域中。
並列摘要
In this study, using the piezoelectric materials to generate Rayleigh Surface Acoustic Wave (R-SAW) combined with microfluidic technology to separate nanoparticles, and the separation system and finite element method (FEM) analysis were proposed. The simulation results are compared with the results of measurement and experimental operation, and the frequency response of the SAW separation chip and the particle trajectory of acoustic radiation force are established. The FEM simulates the scattering parameters and impedances of the surface acoustic wave model with different Interdigital Transducers (IDT) structures and compare with the actual chip parameters by the network analyzer (NA). By comparison, the measured resonance frequency is consistent with the simulation result. In addition, the particle trajectory was shown in MATLAB and is similar with the experimental results. In the research, the IDTs were fabricated on a 4-inch 128°YX-LiNbO3 using semiconductor process technology, and microchannels were fabricated using soft-lithography technology to complete the SAW separation chip. A dual-port AC signal with a peak of 12.5 volts at 12.8MHz is applied to separate the 10μm and 3μm particles, and has the separation efficiency of 95%. We demostrate the IDTs with the reflection grating structure has lower insertion loss and a signal with a peak of 21 volts at 40MHz is applied to separate the 200nm and 500nm nanoparticles. The Dynamic Light Scattering (DLS) was used for analysis, the separation efficiency is as high as 93%. Surface acoustic wave, as a separation technology, has the characteristics of simple structure, low cost, and high flux. Its advantages are fast separation rate, high purity and non-contact separation. The SAW technology is widely used in various fields.