以微流道結構製作三維軟性微電極陣列

A Three-dimensional Flexible Microelectrode Array Assembled through Microchannel Alignment

陳立軒(Li-Shuan Chen)

指導教授 ： 饒達仁

國立清華大學/工學院/動力機械工程學系/碩士(2011年)

https://doi.org/10.6843/NTHU.2011.00423

摘要

本研究主要目的為開發製作一高密度之「軟性立體微電極陣列」。生物體的大腦內含有數量龐大的神經細胞，這些神經細胞能夠傳遞外界所帶來的刺激，將其轉變為神經電訊號提供訊息給大腦做出適當的反應，以即時應付外界環境。神經細胞對於生物體如此的重要，其中電訊號所扮演的角色舉足輕重。藉由量測此一神經訊號，可以幫助我們瞭解生物體對外來刺激的接受與反應情形。
本研究將利用具有柔軟特性的高分子材料Parylene C與SU-8作為微電極的基材，以E-beam薄膜蒸鍍方式沉積金電極並配合黃光微影製程、PDS高分子沉積Parylene C作為金電極絕緣層；利用SU-8厚光阻製作探針之幾何結構，接著以RIE氧電漿乾式蝕刻出探針結構間之鉸鍊，最後以陽極金屬溶解法釋放晶片；在晶片完成後，將晶片各區塊相互折疊固定形成立體結構以PDMS固定，最後以ACF異方性導電膠帶熱壓連接印刷電路板做電性連接，完成一具有量測生物神經訊號之微電極陣列。目前所完成的微電極陣列，經過電化學介面阻抗的量測，其阻抗可達125 kΩ；利用所製作的微電極陣列亦可成功地紀錄到斑馬魚心臟之心電圖。

關鍵字

微電極 ； 陣列 ； 軟性探針

並列摘要

Human’s brain is found of millions of neural cell, these cells transmit electric signal in order to communication with each other. In order to realize the function of neural signal, scientist implant electrode to record the neural signal. There are kinds of microprobe for improving the performance of neural signal recording such as microwire probe silicon based probe, and polymer based probes. Polymer based probes show better performance in long term neural signal recording because of its soft structure and high biocompatibility. In the past we reported an electrostatic actuation process to fold the planar probes to be the arbitrary orientations of three-dimensional probes for neuroscience application. Now we developed a novel MEA with 2 × 2, 4 × 4 and 6 × 6 electrodes packaging by microchannel flow. By using Parylene C, SU-8 and gold as the materiel, we use E-beam evaporation, polymer deposit system (PDS), lithography fabrication, reacting ion etching (RIE) and anodic metal dissolution method to fabricate the microelectrode array. After the fabrication finished, we folded the chip step by step and alignment it by using an alignment column. Fixing each layer by adding PDMS liquid into the microchannel and heating for an hour to solid the flow. After complete the packaging of probes chip, the connection between chip and PCB should be found. In this part we used anisotropic conductive film (ACF) to build the connection. There are solder coating on the bonding pad of the PCB so that it could be heat and melt to fill the gap between the chip and bonding pad. After finished the package, an implant test for the designed probe should be precede. The result indicates that the designed probes have satisfied the request for our implant purpose. The designed MEA implanted into a bio-gel successfully for the implant test. For the impedance measurement, MEA shows 125 kΩ at 1 kHz, phase -60°. A 600 μV potential change was obtained in electrocardiography measurement of zebrafish.

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