Micro-ball lens array fabrication in photoresist using PTFE hydrophobic effect

Abstract

This paper presents a simple method for fabricating a micro-ball lens and its array. The core technology involves the hydrophobic characteristics of polyterafluoroethylene (PTFE) substrate. High contact angle between the melted photoresist pattern and PTFE generates the micro-ball lens and array. The PTFE thin film is spun onto a silicon wafer and oven dried. Photoresist AZ4620 is used to pattern micro-columns with various diameters; 60, 70 and 80 mu m. A thermal reflow process is then applied to melt these micro-column patterns into a micro-ball lens array. The achieved micro-ball lens array has a diameter of 98 mu m fabricated using 80 mu m diameter patterns. This method provides a simple fabrication process and low material cost

An Ultrasensitive Silicon Photonic Ion Sensor Enabled by 2D Plasmonic Molybdenum Oxide

“…There should be no resonant wavelength shift or transmission power drop down. Due to the relative high hydrophobicity of PTFE, water molecules rarely diffuse into the interlayer of H 0.3 MoO 3 and the interface between H 0.3 MoO 3 and silicon. Therefore, the deposited 2D H 0.3 MoO 3 can be maintained on the device surface even after at least 39 consecutive tests.…”

Controllable Fabrication of Highly Ordered Spherical Microcavity Arrays by Replica Molding of In Situ Self-Emulsified Droplets

“…2−5 In recent years, spherical hollow features have attracted considerable attention from scientists and engineers due to their wide applications in biomedical and optical fields. Extensive efforts have therefore been devoted to the construction of spherical microcavities, including thermally reflowed microball molding, 6,7 magnetassisted microbead molding, 8,9 gas expansion molding, 10−14 and droplet molding. 15−21 Due to the geometrical contraction of the spherical microcavity's opening, the replication of spherical microcavities from microballs or microbeads inevitably suffers from the difficulty of demolding or even obtaining fractured spherical microcavities.…”

“…For example, microlens arrays require relief microstructures with smooth convex surface profiles, and in vitro modeling of blood vessels requires circular microchannels. − In recent years, spherical hollow features have attracted considerable attention from scientists and engineers due to their wide applications in biomedical and optical fields. Extensive efforts have therefore been devoted to the construction of spherical microcavities, including thermally reflowed microball molding, , magnet-assisted microbead molding, , gas expansion molding, − and droplet molding. − Due to the geometrical contraction of the spherical microcavity’s opening, the replication of spherical microcavities from microballs or microbeads inevitably suffers from the difficulty of demolding or even obtaining fractured spherical microcavities. The gas expansion molding method offers an elegant solution for this problem, which exploits the expansion of air trapped inside the patterned pits to fabricate the spherical microcavity arrays without requiring demolding.…”

Facile fabrication of microlenses with controlled geometrical characteristics by inkjet printing on nanostructured surfaces prepared by combustion chemical vapour deposition

“…The posts were later thermally treated to melt the resist leading, through a thermal reflow process, to a lens with a spherical profile dictated by surface tension. Curing of the photoresist ultimately stabilizes the final microlens shape [11,12]. Other photolithographic approaches such as gray-scale microlens projection as well as other chemical or mechanical methods, for example hot embossing, have also been used in the production of microlens arrays with well-defined profiles redirecting light in a controlled fashion [13][14][15][16].…”