Chen Po-Jui, Shih Chi-Yuan, Tai Yu-Chong
Department of Electrical Engineering, Divison of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA.
Lab Chip. 2006 Jun;6(6):803-10. doi: 10.1039/b600224b. Epub 2006 Mar 30.
This paper presents a novel channel fabrication technology of bulk-micromachined monolithic embedded polymer channels in silicon substrate. The fabrication process favorably obviates the need for sacrificial materials in surface-micromachined channels and wafer-bonding in conventional bulk-micromachined channels. Single-layer-deposited parylene C (poly-para-xylylene C) is selected as a structural material in the microfabricated channels/columns to conduct life science research. High pressure capacity can be obtained in these channels by the assistance of silicon substrate support to meet the needs of high-pressure loading conditions in microfluidic applications. The fabrication technology is completely compatible with further lithographic CMOS/MEMS processes, which enables the fabricated embedded structures to be totally integrated with on-chip micro/nano-sensors/actuators/structures for miniaturized lab-on-a-chip systems. An exemplary process was described to show the feasibility of combining bulk micromachining and surface micromachining techniques in process integration. Embedded channels in versatile cross-section profile designs have been fabricated and characterized to demonstrate their capabilities for various applications. A quasi-hemi-circular-shaped embedded parylene channel has been fabricated and verified to withstand inner pressure loadings higher than 1000 psi without failure for micro-high performance liquid chromatography (microHPLC) analysis. Fabrication of a high-aspect-ratio (internal channel height/internal channel width, greater than 20) quasi-rectangular-shaped embedded parylene channel has also been presented and characterized. Its implementation in a single-mask spiral parylene column longer than 1.1 m in a 3.3 mm x 3.3 mm square size on a chip has been demonstrated for prospective micro-gas chromatography (microGC) and high-density, high-efficiency separations. This proposed monolithic embedded channel technology can be extensively implemented to fabricate microchannels/columns in high-pressure microfluidics and high-performance/high-throughput chip-based micro total analysis systems (microTAS).
本文介绍了一种在硅衬底中制造体微机械加工的单片嵌入式聚合物通道的新型通道制造技术。该制造工艺有利地避免了表面微机械加工通道中对牺牲材料的需求以及传统体微机械加工通道中的晶圆键合。在微加工通道/柱中选择单层沉积的聚对二甲苯C（聚对苯二甲撑二甲基苯）作为结构材料来进行生命科学研究。借助硅衬底支撑，这些通道可获得高压容量，以满足微流体应用中高压加载条件的需求。该制造技术与进一步的光刻CMOS/MEMS工艺完全兼容，这使得制造的嵌入式结构能够与片上微/纳传感器/致动器/结构完全集成，用于小型化的芯片实验室系统。描述了一个示例性工艺，以展示在工艺集成中结合体微机械加工和表面微机械加工技术的可行性。已经制造并表征了具有通用横截面轮廓设计的嵌入式通道，以展示其在各种应用中的能力。制造了一个准半圆形嵌入式聚对二甲苯通道，并经过验证，该通道能够承受高于1000 psi的内部压力载荷而不失效，可用于微型高效液相色谱（microHPLC）分析。还介绍并表征了一种高纵横比（内部通道高度/内部通道宽度大于20）的准矩形嵌入式聚对二甲苯通道。已经证明其在芯片上3.3 mm×3.3 mm方形尺寸的长度超过1.1 m的单掩膜螺旋聚对二甲苯柱中的应用，可用于未来的微型气相色谱（microGC）以及高密度、高效分离。所提出的单片嵌入式通道技术可广泛应用于制造高压微流体和基于芯片的高性能/高通量微全分析系统（microTAS）中的微通道/柱。
