Exploiting differential etch rates to fabricate large-scale nozzle arrays with protudent geometry

Abstract

Nozzles with micro and nanometer scale orifices are playing an increasingly important role in many micro and nano devices, processes and characterization applications such as cell sorters, micro deposition of structures and near-field optical scanning. This paper describes a new process that can generate nozzles in a silicon substrate with nozzle walls of silicon nitride and oxide and with protudent geometry around the nozzle orifice. The fabrication process exploits a combination of geometry and differences in etching rates to simultaneously open up the nozzle orifice and pattern the geometry around it. The result is an in-parallel, high-throughput process.

Fabrication and Characterization of Silicon Micro-Funnels and Tapered Micro-Channels for Stochastic Sensing Applications

“…An important parameter to consider is texturization of the surfaces characterized by the presence of micropyramids resulting from the re-deposition of the reaction products as well as the presence of H 2 bubbles acting as “micro-masks” [ 34 - 37 ]. It is known that these artifacts can be minimized through the use of highly concentrated hydroxide solutions (up to 15 M) at temperatures up to 85 °C with or without the addition of isopropyl alcohol (IPA) [ 12 , 35 - 36 ].…”

Mode-tunable, micro/nanoscale electrohydrodynamic deposition techniques for optoelectronic device fabrication

“…64 Copyright 2019, Springer Nature. (b) Parallel nozzle array: integrated metal nozzles, 77 Copyright 2018, AIP Publishing; etched cylindrical silicon nozzles, 78 Copyright 2017, IOP Publishing; etched pyramid silicon nozzles, 81 Copyright 2017, IOP Publishing; machined metal nozzles, 83 Copyright 2013, Taylor & Francis; 3D printed electrospinning, 84 Copyright 2017, IOP Publishing; and electrospray 85 nozzles, Copyright 2017, Royal Society of Chemistry. (c) Addressable nozzle array with different controlling methods: by rotating the individual nozzle, 86 Copyright 2012, IOP Publishing; or by controlling the potential of the ring electrodes, 87 Copyright 2015, AIP Publishing.…”

“…Assembling a plurality of stainless-steel nozzles or glass capillaries into a nozzle array is a simple and effective method, 77 but these coarse nozzle arrays with mm-level spacing cannot meet the requirements for high density and accuracy. Using MEMS-based techniques to prepare high-precision glass or silicon nozzle arrays has gradually become a focus, and various high-precision cylindrical [78][79][80] and pyramid-shaped nozzle arrays 81 have been fabricated. Besides MEMS-based technology, special processing techniques like laser etching, 82 micro-machining 83 and high-precision 3D printing 84,85 also show tremendous potential in EHD nozzle array fabrication.…”

High density, addressable electrohydrodynamic printhead made of a silicon plate and polymer nozzle structure

“…Pan et al 31 fabricated silicon multi-nozzles by photolithography and etching. Mukhopadhyay et al 32 developed high-precision pyramid-shaped nozzle arrays with a rectangle outlet on a silicon substrate. Ohigashi et al 33 utilized a MEMS micromachining process to develop nozzle arrays with a small inner/outer diameter and nozzle spacing.…”