准分子激光微加工技术结合模塑技术加工微流控芯片

Fabrication of Microfluidic Chip with Two-Step Using Excimer Laser Ablation Micromachining Technique and Replica Molding Technology

利用准分子激光微加工技术与模塑技术相结合的方法制造微流控芯片。用准分子激光在玻璃基胶层上刻蚀出加工质量较高的微流控生物芯片形貌,通过电铸技术对微流控芯片进行复制,得到反向金属模具。用金属模具通过注塑成型技术用聚碳酸酯注塑出微流控芯片。系统研究了准分子激光的能量密度和工作台移动速度对胶层微通道加工质量的影响;测量并分析了激光刻蚀加工出的微流控芯片原型、电铸的反向金属模板和注塑成型后的微流控芯片的轮廓精度和表面粗糙度,上表面尺度偏差不大于2μm,底面粗糙度小于20 nm。对注塑出的微流控芯片和激光直写刻蚀的几何结构相同的微流控芯片的流动性能进行比较测试。在流速较小时,用激光微加工技术与模塑技术相结合的方法加工的微通道比准分子激光直写法所加工的微通道流动性能更好。

We present an effective and low-cost method for fabricating microfluidic chip based on excimer laser direct-writing ablation and replica molding. It is based on a newly excimer laser micromachining technique that can accurately machine microfluidic chip microstructure with smooth surface profile. Microfluidic chips with precise and smooth surface profiles are ablated by direct laser machining on an epoxy glue layer sticking on glass substrates. Laser-machined microfluidic chips are replicated by electroforming to obtain inverse metal molds. Finally, polycarbonate （PC） microfluidic chips are replicated from these metal molds using injection molding method. The relation between the process parameters （the translational speed of working platform and the laser fluence） and the micromachining quality （the depth and surface of the microchannel） is investigated. The profile accuracy and surface roughness of the produced microfluidic chip at each stage are measured and monitored. The average upper surface profile accuracy is better than 2 μm and the average surface roughness is less than 20 nm. Experimental data show the controllability and accuracy of this micromachining process. Experimental investigation is performed on the flow characteristics of water in two different roughness rectangle microchannels. The flow characteristics of water in the microchannels fabricated with the proposed combination method are better than those in the microchannels fabricated with laser direct-writing when the flow velocity is small.