整合微流管及溶液電導度量測奈升流體系統

Abstract

在微機電領域裡，微流系統中的微流管結構在近幾年來都被廣泛地討論與研究，其中用犧牲層來作微流管的製造方法即使稍嫌複雜，卻是目前IC製造技術裡最常用且最簡單的方法。在微流管頂壁用以蝕刻的孔洞被打開以便於蝕刻底下的犧牲氧化層後，金屬鋁被濺鍍到整片晶片上以填住這些蝕刻孔洞並密封住整個微流管。接下來利用黃光技術將這層鋁開出以做為微流管通道兩旁的成對電極，當施加定電壓在這成對的電極上後，可導電的電解質溶液流到這成對的電極上，電流就會產生。依照這個原理，在微流管裡置放數以百計的成對電極，如此一來注入此微流管的流速也可輕易的量測。在本實驗中，最大的微流管體積是1奈升(1 nl)且在通道裡置入100對成對電極，也就是說，對最大的100微米寬度的微流管而言，其精準度是10 pl，而對最小寬度的微流管而言精準度竟只有0.5 pl。

Microchannel structure of microfluidic system in MEMS technology has been widely studied recently. Method of using sacrificial layer to fabricate microchannel is the mostly used, simple and compatible in the conventional IC fabrication process even if it is a little complex. In order to seal the whole microchannel, aluminum is sputtered onto the blanked wafer after the etching holes are opened on the channel top so as to etch down the sacrificial layer clearly. Next we define the aluminum film as electrodes of two rows at the opposite sides of the channel. By placing the aluminum electrodes of a pair in the channel, the flowing current turns on for applying constant voltage when the injected electrolytic solutions approach the electrodes. For this reason the flowing rate in this microchannel can be easily detected by means of locating a large number of pairs of electrodes. In the experiment the largest microchannel volume is 1 nano-liter (nl) and 100 pairs of electrodes are placed in the channel. It means that the sensitivity of the largest microchannel that is 100 µm in width is only 10 pico-liter (pl) and the smallest channel is 0.5 pico-liter.