Zamuruyev Konstantin O, Zrodnikov Yuriy, Davis Cristina E
Department of Mechanical and Aerospace Engineering, One Shields Avenue, University of California, Davis, Davis CA 95616, USA.
J Micromech Microeng. 2017 Jan;27(1). doi: 10.1088/0960-1317/27/1/015010. Epub 2016 Oct 28.
Excellent chemical and physical properties of glass, over a range of operating conditions, make it a preferred material for chemical detection systems in analytical chemistry, biology, and the environmental sciences. However, it is often compromised with SU8, PDMS, or Parylene materials due to the sophisticated mask preparation requirements for wet etching of glass. Here, we report our efforts toward developing a photolithography-free laser-patterned hydrofluoric acid-resistant chromium-polyimide tape mask for rapid prototyping of microfluidic systems in glass. The patterns are defined in masking layer with a diode-pumped solid-state laser. Minimum feature size is limited to the diameter of the laser beam, 30 μm; minimum spacing between features is limited by the thermal shrinkage and adhesive contact of the polyimide tape to 40 μm. The patterned glass substrates are etched in 49% hydrofluoric acid at ambient temperature with soft agitation (in time increments, up to 60 min duration). In spite of the simplicity, our method demonstrates comparable results to the other current more sophisticated masking methods in terms of the etched depth (up to 300 μm in borosilicate glass), feature under etch ratio in isotropic etch (~1.36), and low mask hole density. The method demonstrates high yield and reliability. To our knowledge, this method is the first proposed technique for rapid prototyping of microfluidic systems in glass with such high performance parameters. The proposed method of fabrication can potentially be implemented in research institutions without access to a standard clean-room facility.
在一系列操作条件下，玻璃具有出色的化学和物理性能，这使其成为分析化学、生物学和环境科学中化学检测系统的首选材料。然而，由于玻璃湿法蚀刻对掩膜制备要求复杂，玻璃材料常与SU8、聚二甲基硅氧烷（PDMS）或聚对二甲苯材料配合使用。在此，我们报告了为玻璃微流控系统快速原型制作开发一种无需光刻的激光图案化耐氢氟酸铬 - 聚酰亚胺胶带掩膜所做的努力。图案通过二极管泵浦固态激光在掩膜层中定义。最小特征尺寸限制为激光束直径30μm；特征之间的最小间距受聚酰亚胺胶带的热收缩和粘性接触限制，为40μm。图案化的玻璃基板在室温下于49%的氢氟酸中进行软搅拌蚀刻（以时间增量进行，最长持续60分钟）。尽管方法简单，但就蚀刻深度（硼硅酸盐玻璃中可达300μm）、各向同性蚀刻中的特征欠蚀刻率（约1.36）和低掩膜孔密度而言，我们的方法与其他当前更复杂的掩膜方法取得了相当的结果。该方法具有高成品率和可靠性。据我们所知，这种方法是首次提出的用于玻璃微流控系统快速原型制作且具有如此高性能参数的技术。所提出的制造方法有可能在没有标准洁净室设施的研究机构中实施。
