A digital microfluidic chip by electrostatic manipulation was designed and fabricated for a micro total analysis system. The principle of the electrostatic manipulation was proposed and the fabrication processes and experimental platform were demonstrated. For the chip, the silicon was taken as a substrate,a silicon oxide film as the insulating layer,a TiW/Au film as the electrode array, a Si3N4 film as the dielectric layer, and the fluorocarbon polymer as the hydrophobic layer. With an open structure instead of complex sandwich structure, the chip just needed a coplanar controlling electrode with one layer, so the process was simplified greatly. As the electrode array was embeded in the SiO2, the electric leakage from poor step coverage and dielectric breakdown at the margin were prevented.Furthermore, with thin dielectric layer and fine hydrophobic layer, the manipulating voltage was reduced greatly. Experiments show that,by controlling the sequence of voltage to the electrode array,the droplet can be transported smoothly in the two-dimension planes with a programmable manner at a low voltage of 20 V, and the maximum speed has reached 96 mm/s. The digital microfluidic chip can be used in a Lab-on-chip due to its simple structure and IC compatible fabrication processes.%设计并制作了一种基于静电力驱动的数字微流控芯片,用于构建芯片实验室.介绍了静电力驱动原理和芯片制作工艺流程,搭建了驱动检测实验平台.该芯片采用硅作衬底,氧化硅作绝缘层,TiW/Au为驱动电极阵列,氮化硅作介质层,碳氟聚合物为疏水层.由于采用开放式的结构,只需单层共平面控制电极,简化了工艺流程,优化了器件结构;而驱动电极阵列嵌入在氧化硅中,改善了减小介质层厚度时介质层对金属的台阶覆盖性,减少了电极边沿突起引起的边界击穿.另外,采用较薄的高质量介质层和疏水性能好的疏水膜层,大大降低了液滴驱动电压.实验显示,在20 V驱动电压下,该工艺可实现液滴按程序设定方式在二维平面内流畅运动,最大运动速度达96 mm/s.提出的芯片制作工艺简单,与IC工艺兼容,可应用于生化分析芯片实验室系统.
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