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Maskless lithography based on digital micromirror device (DMD) and double sided microlens and spatial filter array
摘要： A new type of maskless lithography system based on digital mirror device (DMD) is proposed, constructed, and experimentally demonstrated. It includes a pin-hole array sandwiched by two microlens arrays on each side, known as double-sided microlens/spatial-filter array (D-MSFA), and aligned with a DMD. Ultraviolet (UV) light reflected by DMD is first collected by the first microlens array, filtered through the pin-hole array, and then re-focused by the second microlens array into a UV spot array. Along with an obliquely scanning method, this D-MSFA/DMD-based maskless lithography system can perform not only 2D but also 3D UV patterning. Experimental testing successfully generates complicated patterns with a minimum line-width of 3.36 μm. Direct 3D patterning and 3D microfabrication are also experimentally demonstrated on a photoresist layer. Excellent profile accuracy and surface structure qualities are observed with great potentials for future 2D and 3D microfabrication in a maskless manner.
关键词： Microlens array,Maskless lithography,Digital mirror device (DMD),3D microfabrication
更新于2025-09-23 15:22:29
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Low-Cost Fabrication of Polymer Based Micro-Optical Devices for Application in Illumination, Sensing, and Optical Interconnects
摘要： Fabrication of desired micro structures in polymers is always of keen interest for applications in illumination optics, sensors and optical interconnects. The challenge is to fabricate structures in the sub-micron range but at low cost. Among other fabrication methods as described in [1], maskless lithography tends to be cost effective and can create sub-micron structures. Here, we present a simple and low-cost fabrication process chain for fabricating desired micro structures in polymer, i.e. PMMA. The microstructures are, for example, grating structures and straight waveguides. The fabrication is done using a maskless lithography setup which employs a spatial light modulator and a UV LED. For recording the microstructure pattern a grayscale photoresist, i.e. OrmoComp, is used, which is coated on the silicon substrate. For writing waveguides, a translation stage is included in the setup to stitch the single exposure patterns together to form a continuous waveguide structure, as can be seen in Fig. 1(c). For replication an intermediate stamp, which is stable at high thermal loads, is obtained by casting Polydimethyl siloxane (PDMS) in an oven for 15 mins at 100 0C. The stamp is then used to replicate the microstructures onto the Polymethyl methacrylate (PMMA) using a hot embossing system, i.e. Jenoptik HEX03. A 500 μm thick PMMA (Plexiglas XT99524, Thyssen Krupp) foil is placed on the PDMS (ELASTOSIL RT 607A/B) stamp and an embossing pressure of 7 kPa is applied for 4 mins. After cooling to a release temperature of 40 0C, the PMMA foil is removed manually.
关键词： micro-optical devices,PDMS,optical interconnects,illumination,polymer,sensing,maskless lithography,PMMA,hot embossing
更新于2025-09-19 17:13:59
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Thermoplasmonic Maskless Lithography on Upconverting Nanocomposites Assisted by Gold Nanostars
摘要： Photothermal effects in plasmonic nanoparticles can be used to locally modify temperature-sensitive materials. Polylactic acid (PLA) is a thermoplastic biodegradable polymer with a glass transition temperature around 60 ?C that has been popularized as a feedstock material for 3D printing. Here, we extend its use to produce thin PLA films that can be modified at the microscopic level when covered with gold nanostars (AuNSs). The heat dissipation generated when exciting the plasmon resonance of AuNSs, under exposure to 976 nm focused laser light, produce an increase in the local temperature of more than 100 ?C. When the temperature surpasses the glass transition of the base PLA layer, AuNSs get attached to the polymer surface. The following dissolution of the unexposed material in acetone bath permits the precise control of the engraving process at the microscale. Furthermore, Er3+ doped upconverting nanoparticles embedded into the PLA layer can act as optical nanothermometers to probe the local temperature, simultaneously allowing the visualization of the laser spot. A computer numerical control (CNC) system was developed to drive the laser writing beam and transfer 2D patterns, opening up the thermoplasmonic maskless lithography technique. Suitable for rigid and flexible substrates coated with PLA, the methods and materials developed here were applied to produce patterned substrates for surface enhanced Raman spectroscopy, and luminescent optical encoding for anti-counterfeiting technologies.
关键词： photothermal nanoparticles,gold nanostars,optical thermometry,thermoplasmonics,maskless lithography,upconversion nanoparticles
更新于2025-09-16 10:30:52