Archer Marie J, Ligler Frances S
U. S. Naval Research Laboratory, Center for Biomolecular Science and Engineering 4555 Overlook, USA.
Sensors (Basel). 2008 Jun 9;8(6):3848-3872. doi: 10.3390/s8063848.
We present a simplified, highly reproducible process to fabricate arrays of tapered silicon micro-funnels and micro-channels using a single lithographic step with a silicon oxide (SiO2) hard mask on at a wafer scale. Two approaches were used for the fabrication. The first one involves a single wet anisotropic etch step in concentrated potassium hydroxide (KOH) and the second one is a combined approach comprising Deep Reactive Ion Etch (DRIE) followed by wet anisotropic etching. The etching is performed through a 500 mm thick silicon wafer, and the resulting structures are characterized by sharp tapered ends with a sub-micron cross-sectional area at the tip. We discuss the influence of various parameters involved in the fabrication such as the size and thickness variability of the substrate, dry and wet anisotropic etching conditions, the etchant composition, temperature, diffusion and micro-masking effects, the quality of the hard mask in the uniformity and reproducibility of the structures, and the importance of a complete removal of debris and precipitates. The presence of apertures at the tip of the structures is corroborated through current voltage measurements and by the translocation of DNA through the apertures. The relevance of the results obtained in this report is discussed in terms of the potential use of these structures for stochastic sensing.
我们展示了一种简化的、高度可重复的工艺,用于在晶圆规模上使用带有氧化硅(SiO₂)硬掩膜的单一光刻步骤制造锥形硅微漏斗和微通道阵列。该制造过程采用了两种方法。第一种方法是在浓氢氧化钾(KOH)中进行单一的湿法各向异性蚀刻步骤,第二种方法是一种组合方法,包括深反应离子蚀刻(DRIE),随后进行湿法各向异性蚀刻。蚀刻过程通过500毫米厚的硅晶圆进行,所得结构的特征是具有尖锐的锥形末端,尖端处的横截面积为亚微米级。我们讨论了制造过程中涉及的各种参数的影响,如衬底的尺寸和厚度变化、干法和湿法各向异性蚀刻条件、蚀刻剂成分、温度、扩散和微掩膜效应、硬掩膜的质量对结构均匀性和可重复性的影响,以及完全去除碎片和沉淀物的重要性。通过电流电压测量以及DNA通过这些孔的转运,证实了结构尖端存在孔。本报告中获得的结果的相关性将根据这些结构在随机传感方面的潜在用途进行讨论。