35 results match your criteria negative-tone photoresist

Electronic Tuning of Monolayer Graphene with Polymeric "Zwitterists".

ACS Nano 2021 Feb 29;15(2):2762-2770. Epub 2021 Jan 29.

Faculty of Engineering and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel.

Work function engineering of two-dimensional (2D) materials by application of polymer coatings represents a research thrust that promises to enhance the performance of electronic devices. While polymer zwitterions have been demonstrated to significantly modify the work function of both metal electrodes and 2D materials due to their dipole-rich structure, the impact of zwitterion chemical structure on work function modulation is not well understood. To address this knowledge gap, we synthesized a series of sulfobetaine-based zwitterionic random copolymers with variable substituents and used them in lithographic patterning for the preparation of negative-tone resists (, "zwitterists") on monolayer graphene. Read More

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February 2021

Lithographic Performance of Aryl Epoxy Thermoset Resins as Negative Tone Photoresist for Microlithography.

Polymers (Basel) 2020 Oct 14;12(10). Epub 2020 Oct 14.

Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

Photoresists (or photo-resins) are the main and most important raw material used for lithography techniques such as deep X-ray (DXRL), ultraviolet (UVL), deep-UV (DUVL), and extreme UV (EUVL). In previous work, we showed how complicated could be the synthesis of the resins used to produce photoresist. In this study, we follow up on the strategy of tuning deep and macro levels of properties to formulate photo-resins. Read More

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October 2020

Two-Color Pixel Patterning for High-Resolution Organic Light-Emitting Displays Using Photolithography.

Micromachines (Basel) 2020 Jun 30;11(7). Epub 2020 Jun 30.

Department of Materials Science and Engineering, University of Seoul, Seoul 02504, Korea.

Nowadays, the display industry is endeavoring to develop technology to provide large-area organic light-emitting diode (OLED) display panels with 8K or higher resolution. Although the selective deposition of organic molecules through shadow masks has proven to be the method of choice for mobile panels, it may not be so when independently defined high-resolution pixels are to be manufactured on a large substrate. This technical challenge motivated us to adopt the well-established photolithographic protocol to the OLED pixel patterning. Read More

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Multi-layering of SU-8 exhibits distinct geometrical transitions from circular to planarized profiles.

Biomicrofluidics 2020 Jan 21;14(1):014116. Epub 2020 Feb 21.

Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794, USA.

The negative tone photoresist SU-8 permits the creation of micrometer-scale structures by optical lithography. It is also the most used photoresist in soft lithography for the fast-prototyping of microfluidic devices. Despite its importance, the effect of capillary forces on SU-8 multi-layering onto topographical features has not been thoroughly studied. Read More

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January 2020

Epoxy Resins for Negative Tone Photoresists.

Polymers (Basel) 2019 Sep 6;11(9). Epub 2019 Sep 6.

Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

One of the types of negative tone photoresists is composed of at least a catalyst, a solvent, and epoxy resin. This is the primary raw material for lithography technology. To ensure high-quality pattern transfer in the lithography process, it is crucial to control the properties of the photoresist. Read More

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September 2019

Light-Activated Hybrid Nanocomposite Film for Water and Oxygen Sensing.

ACS Appl Mater Interfaces 2018 Sep 5;10(37):31745-31754. Epub 2018 Sep 5.

Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , P.O. Box 2008, Oak Ridge , Tennessee 37831-6496 , United States.

Oxygen and water vapor sensing properties are investigated in metal-oxide-hybrid polymer nanocomposite thin films generated by infiltration synthesis, which incorporates molecular ZnO into the matrix of SU-8 polymer, a common negative-tone photoresist. The hybrid thin films display 20-fold higher gravimetric responses to oxygen and water vapor than those of control ZnO thin films in the dark. An additional 50-500% enhanced responses are detected under UV irradiation. Read More

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September 2018

Use of SU8 as a stable and biocompatible adhesion layer for gold bioelectrodes.

Sci Rep 2018 04 3;8(1):5560. Epub 2018 Apr 3.

Imperial College London, Exhibition Road, South Kensington, London, SW7 2AY, UK.

Gold is the most widely used electrode material for bioelectronic applications due to its high electrical conductivity, good chemical stability and proven biocompatibility. However, it adheres only weakly to widely used substrate materials such as glass and silicon oxide, typically requiring the use of a thin layer of chromium between the substrate and the metal to achieve adequate adhesion. Unfortunately, this approach can reduce biocompatibility relative to pure gold films due to the risk of the underlying layer of chromium becoming exposed. Read More

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Polyarylenesulfonium Salt as a Novel and Versatile Nonchemically Amplified Negative Tone Photoresist for High-Resolution Extreme Ultraviolet Lithography Applications.

ACS Appl Mater Interfaces 2017 01 27;9(1):17-21. Epub 2016 Dec 27.

School of Basic Sciences and ‡School of Computing and Electrical Engineering, Indian Institute of Technology Mandi , Kamand 175 005, Himachal Pradesh, India.

The present report demonstrates the potential of a polyarylenesulfonium polymer, poly[methyl(4-(phenylthio)-phenyl)sulfoniumtrifluoromethanesulfonate] (PAS), as a versatile nonchemically amplified negative tone photoresist for next-generation lithography (NGL) applications starting from i-line (λ ∼ 365 nm) to extreme ultraviolet (EUV, λ ∼ 13.5 nm) lithography. PAS exhibited considerable contrast (γ), 0. Read More

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January 2017

Cloning SU8 silicon masters using epoxy resins to increase feature replicability and production for cell culture devices.

Biomicrofluidics 2015 May 23;9(3):036502. Epub 2015 Jun 23.

Department of Chemistry, University of North Carolina at Chapel Hill , Campus Box 3290, Chapel Hill, North Carolina 27599, USA.

In recent years, there has been a dramatic increase in the use of poly(dimethylsiloxane) (PDMS) devices for cell-based studies. Commonly, the negative tone photoresist, SU8, is used to pattern features onto silicon wafers to create masters (SU8-Si) for PDMS replica molding. However, the complexity in the fabrication process, low feature reproducibility (master-to-master variability), silane toxicity, and short life span of these masters have been deterrents for using SU8-Si masters for the production of cell culture based PDMS microfluidic devices. Read More

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Synthesis of triphenylsulfonium triflate bound copolymer for electron beam lithography.

J Nanosci Nanotechnol 2014 Aug;14(8):6270-3

Photoacid generator (PAG) has been widely used as a key component in photoresist for high-resolution patterning with high sensitivity. A novel acrylic monomer, triphenylsulfonium salt methyl methacrylate (TPSMA), was synthesized and includes triphenylsulfonium triflate as a PAG. The poly(MMA-co-TPSMA) (PMT) as a polymer-bound PAG was synthesized with methyl methacrylate (MMA) and TPSMA for electron beam lithography. Read More

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Parallel near-field photolithography with metal-coated elastomeric masks.

Langmuir 2015 Jan 14;31(3):1210-7. Epub 2015 Jan 14.

Key Laboratory of Flexible Electronic (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM) and ⊥College of Science, Nanjing Technological University , Nanjing 211816, China.

Developing a cost-effective nanolithography strategy that enables the production of subwavelength features with various shapes over large areas is a long-standing goal in the nanotechnology community. Herein, an inexpensive nanolithographic technique that combines the wafer-scale production capability of photolithography with the subwavelength feature size controllability of near-field photolithography was developed to fabricate centimeter-scale up to wafer-scale sub-100-nm variously shaped nanopatterns on surfaces. The wafer-scale elastomeric trench-based photomasks with subwavelength apertures created at the apexes were compatible with mask aligners, allowing for the production of wafer-scale subwavelength nanopatterns with adjustable feature sizes, shapes, and periodicities. Read More

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January 2015

Print-to-Pattern Dry Film Photoresist Lithography.

J Micromech Microeng 2014 May;24(5):057002

Micro-Nano Innovations (MiNI) Laboratory, Department of Biomedical Engineering, University of California, Davis Davis, CA 95616 (USA).

Here we present facile microfabrication processes, referred to as Print-to-Pattern dry film photoresist (DFP) lithography, that utilize the combined advantages of wax printing and DFP to produce micropatterned substrates with high resolution over a large surface area in a non-cleanroom setting. The Print-to-Pattern methods can be performed in an out-of-cleanroom environment making microfabrication much more accessible to minimally equipped laboratories. Two different approaches employing either wax photomasks or wax etchmasks from a solid ink desktop printer have been demonstrated that allow the DFP to be processed in a negative tone or positive tone fashion, respectively, with resolutions of 100 μm. Read More

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Dual photosensitive polymers with wavelength-selective photoresponse.

Adv Mater 2014 Aug 15;26(29):5012-7. Epub 2014 May 15.

Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128, Mainz, Germany.

Polyurethane thin films that photopolymerize and photodegrade upon exposure to light of different wavelengths are presented. The chromic response is based on two caged monomers with the ability to be activated or photocleaved with different wavelengths under single and two-photon excitation. This material represents a dual photoresist with "positive" and "negative" tone contained in a single resist formulation and with the ability to generate complex 2D and 3D patterns. Read More

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SU-8 bonding protocol for the fabrication of microfluidic devices dedicated to FTIR microspectroscopy of live cells.

Lab Chip 2014 Jan;14(1):210-8

CNR-IOM, TASC laboratory, S. S. 14 km 163.5 Basovizza, 34149 Trieste, Italy.

Here we present a new bonding protocol for SU-8 negative tone photoresist that exploits the chemical modifications induced in the resin by exposure to 254 nm (UVC) light. Fourier Transform Infrared microspectroscopy (μ-FTIR) was used to carry out a thorough study on the chemical processes and modifications occurring within the epoxy resin by exposure to 365 nm and 254 nm light. In particular, we established that UVC light promotes the opening of the epoxy rings bypassing the post-exposure bake. Read More

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January 2014

Photolithographic olefin metathesis polymerization.

J Am Chem Soc 2013 Nov 30;135(45):16817-20. Epub 2013 Oct 30.

Arnold and Mabel Beckman Laboratories for Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.

Patterning functional materials is a central challenge across many fields of science. The ability to lithographically fabricate micro- and nanostructures has been one of the most impactful technological breakthroughs of the last century. In part due to the complexity of the chemical processes in photoresists, there is a limited variety of materials that can currently be patterned by photolithography. Read More

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November 2013

Characterization of single α-tracks by photoresist detection and AFM analysis-focus on biomedical science and technology.

Phys Med Biol 2013 Nov 11;58(21):7673-82. Epub 2013 Oct 11.

Department of Oncology, University of Oxford, MRC/CRUK Gray Institute for Radiation Oncology and Biology, Oxford, UK. Department of Biomedical Science, Tshwane University of Technology, Pretoria, South Africa.

The interactions between energetic ions and biological and/or organic target materials have recently attracted theoretical and experimental attention, due to their implications for detector and device technologies, and for therapeutic applications. Most of the attention has focused on detection of the primary ionization tracks, and their effects, while recoil target atom tracks remain largely unexplored. Detection of tracks by a negative tone photoresist (SU-8), followed by standard development, in combination with analysis by atomic force microscopy, shows that both primary and recoil tracks are revealed as conical spikes, and can be characterized at high spatial resolution. Read More

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November 2013

Nanoscopic cylindrical dual concentric and lengthwise block brush terpolymers as covalent preassembled high-resolution and high-sensitivity negative-tone photoresist materials.

J Am Chem Soc 2013 Mar 12;135(11):4203-6. Epub 2013 Mar 12.

Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA.

We describe a high-resolution, high-sensitivity negative-tone photoresist technique that relies on bottom-up preassembly of differential polymer components within cylindrical polymer brush architectures that are designed to align vertically on a substrate and allow for top-down single-molecule line-width imaging. By applying cylindrical diblock brush terpolymers (DBTs) with a high degree of control over the synthetic chemistry, we achieved large areas of vertical alignment of the polymers within thin films without the need for supramolecular assembly processes, as required for linear block copolymer lithography. The specially designed chemical compositions and tuned concentric and lengthwise dimensions of the DBTs enabled high-sensitivity electron-beam lithography of patterns with widths of only a few DBTs (sub-30 nm line-width resolution). Read More

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Neutron reflectivity characterization of the photoacid reaction-diffusion latent and developed images of molecular resists for extreme ultraviolet lithography.

Langmuir 2012 May 11;28(20):7665-78. Epub 2012 May 11.

Polymers Division, National Institute of Standards & Technology, Gaithersburg, Maryland 20899, USA.

Lithographic feature size requirements have approached a few radius of gyration of photoresist polymers used in thin-film patterning. Furthermore, the feature dimensions are commensurate with the photoacid diffusion length that defines the underlying latent image. Smaller imaging building blocks may enable reduced feature sizes; however, resolution limits are also dependent upon the spatial extent of the photoacid-catalyzed reaction diffusion front and subsequent dissolution mechanism. Read More

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Combinatorial optimization of a molecular glass photoresist system for electron beam lithography.

Adv Mater 2011 Dec 18;23(45):5404-8. Epub 2011 Oct 18.

Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge, UK.

Electron beam lithography is a powerful technique for the production of nanostructures but pattern quality depends on numerous interacting process variables. Orthogonal gradients of resist composition, baking temperatures, and development time as well as dose variations inside writing fields are used to prepare ternary combinatorial libraries for an efficient stepwise optimization of a molecular glass negative tone resist system. Read More

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December 2011

Oxide nanocrystal based nanocomposites for fabricating photoplastic AFM probes.

Nanoscale 2011 Nov 22;3(11):4632-9. Epub 2011 Aug 22.

CNR-IPCF Sez. Bari c/o Dipartimento di Chimica, Università di Bari, via Orabona 4, Bari, 70126, Italy.

We report on the synthesis, characterization and application of a novel nanocomposite made of a negative tone epoxy based photoresist modified with organic-capped Fe(2)O(3) nanocrystals (NCs). The mechanical properties of the nanocomposite drastically improve upon incorporation of a suitable concentration of NCs in the polymer, without deteriorating its photolithography performance. High aspect ratio 3D microstructures made of the nanocomposite have been fabricated with a uniform surface morphology and with a resolution down to few micrometres. Read More

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November 2011

Advanced lithography simulation for various 3-dimensional nano/microstructuring fabrications in positive- and negative-tone photoresists.

J Nanosci Nanotechnol 2011 Jan;11(1):528-32

Department of Applied Physics, Hanyang University, Ansan 426-791, Korea.

Photoresist lithography has been applied to the fabrication of micro/nano devices, such as microfluidic structures, quantum dots, and photonic devices, in MEMS (micro-electro mechanical systems) and NEMS (nano-electro-mechanical systems). In particular, nano devices can be expected to present different physical phenomena due to their three-dimensional (3D) structure. The flexible 3D micro/nano fabrication technique and its process simulation have become among the major topics needed to understand nano-mechanical phenomena. Read More

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January 2011

Multiphoton photoresists giving nanoscale resolution that is inversely dependent on exposure time.

Nat Chem 2011 Mar 23;3(3):223-7. Epub 2011 Jan 23.

Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.

Recent advances in materials science have made it possible to perform photolithography at the nanoscale using visible light. One approach to visible-light nanolithography (resolution augmentation through photo-induced deactivation) uses a negative-tone photoresist incorporating a radical photoinitiator that can be excited by two-photon absorption. With subsequent absorption of light, the photoinitiator can also be deactivated before polymerization occurs. Read More

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An inorganic-organic diblock copolymer photoresist for direct mesoporous SiCN ceramic patterns via photolithography.

Chem Commun (Camb) 2011 Mar 11;47(12):3484-6. Epub 2011 Feb 11.

National Creative Research Center of Applied Microfluidic Chemistry, Chungnam National University, 220 Kung Dong, Yuseong Gu, Daejeon 305-764, Korea.

A high resolution negative-tone-type of inorganic-organic diblock copolymer photoresist was synthesized as a novel precursor for simple and direct fabrication of SiCN ceramic mesoporous patterns with ordered nanoscale pores by using a "top-down" photolithographic technique and the subsequent sacrificial processes of a "bottom-up" self-assembled nanostructure. Read More

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Selective area control of self-assembled pattern architecture using a lithographically patternable block copolymer.

ACS Nano 2009 Jul 17;3(7):1761-6. Epub 2009 Jun 17.

Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853.

We leverage distinctive chemical properties of the diblock copolymer poly(α-methylstyrene)-block-poly(4-hydroxystyrene) to create for the first time high-resolution selective-area regions of two different block copolymer phase morphologies. Exposure of thin films of poly(α-methylstyrene)-block-poly(4-hydroxystyrene) to nonselective or block-selective solvent vapors results in polymer phase separation and self-assembly of patterns of cylindrical-phase or kinetically trapped spherical-phases, respectively. Poly(4-hydroxystyrene) acts as a high-resolution negative-tone photoresist in the presence of small amounts of a photoacid generator and cross-linker, undergoing radiation-induced cross-linking upon exposure to ultraviolet light or an electron beam. Read More

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Large-core single-mode rib SU8 waveguide using solvent-assisted microcontact molding.

Appl Opt 2008 Sep;47(25):4540-7

1Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195-2600, USA.

This paper describes a novel fabrication technique for constructing a polymer-based large-core single-mode rib waveguide. A negative tone SU8 photoresist with a high optical transmission over a large wavelength range and stable mechanical properties was used as a waveguide material. A waveguide was constructed by using a polydimethylsiloxane stamp combined with a solvent-assisted microcontact molding technique. Read More

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September 2008

Behavior of single DNA molecules in the well-ordered nanopores.

J Chromatogr A 2008 Oct 11;1206(1):72-6. Epub 2008 Jul 11.

Department of Material Science and Engineering, National Chiao Tung University, Hsin Chu 300, Taiwan.

Here we describe a simple approach to fabricate robust three-dimensional periodic porous nanostructures inside the microchannels. In this approach, the colloidal crystals were first grown inside the microchannel using an evaporation-assisted self-assembly process. Then the void spaces among the colloidal crystals were filled with epoxy-based negative tone photoresist. Read More

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October 2008

Three-dimensionally-patterned submicrometer-scale hydrogel/air networks that offer a new platform for biomedical applications.

Nano Lett 2008 May 5;8(5):1456-60. Epub 2008 Apr 5.

Institute for Soldier Nanotechnologies, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

Phase mask interference lithography was employed to fabricate three-dimensional (3D) hydrogel structures with high surface area on neural prosthetic devices. A random terpolymer of poly(hydroxyethyl methacrylate- ran-methyl methacrylate- ran-methacrylic acid) was synthesized and used as a negative-tone photoresist to generate bicontinuous 3D hydrogel structures at the submicrometer scale. We demonstrated that the fully open 3D hydrogel/air networks can be used as a pH-responsive polymeric drug-release system for the delivery of neurotrophins to enhance the performance of neural prosthetic devices. Read More

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Enhanced wettability of SU-8 photoresist through a photografting procedure for bioanalytical device applications.

J Micromech Microeng 2008 Jan;18(4):450131-450137

Department of Chemical and Biological Engineering, 143 Schrenk Hall, Missouri University of Science and Technology (formerly University of Missouri-Rolla), Rolla, MO 65409.

In this work, we detail a method whereby a polymeric hydrogel layer is grafted to the negative tone photoresist SU-8 in order to improve its wettability. A photoinitiator is first immobilized on freshly prepared SU-8 samples, acting as the starting point for various surface modifications strategies. Grafting of a 2-hydroxyethylmethacrylate-based hydrogel from the SU-8 surface resulted in the reduction of the static contact angle of a water droplet from 79 +/- 1 degrees to 36 +/- 1 degrees , while addition of a poly(ethylene glycol)-rich hydrogel layer resulted in further improvement (8 +/- 1 degrees ). Read More

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January 2008

Monolithic integration of well-ordered nanoporous structures in the microfluidic channels for bioseparation.

J Chromatogr A 2007 Aug 27;1162(2):175-9. Epub 2007 Jun 27.

Research Center for Applied Sciences, Academia Sinica, 128, Section 2, Academia Road, Nankang, Taipei 115, Taiwan.

Gel electrophoresis and capillary gel electrophoresis are widely used for the separation of biomolecules. With increasing demand in the miniaturized devices such as lab-on-a-chip, it is necessary to integrate such a separation component into a chip format. Here, we describe a simple approach to fabricate robust three-dimensional periodic porous nanostructures inside the microchannels for the separation of DNA molecules. Read More

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Fabrication of high-resolution periodical structure on polymer waveguides using a replication process.

Opt Express 2007 Jul;15(14):8649-59

This paper describes a procedure to replicate a polymeric wavelength filter. In this work, the grating structure on a polymer is fabricated first using holographic interferometry and micro-molding processes. The polymeric wavelength filters are produced by a two-step molding process where the master mold is first formed on a negative tone photoresist and subsequently transferred to a PDMS mold; following this step, the PDMS silicon rubber mold was used as a stamp to transfer the pattern of the polymeric wavelength filters onto a UV cure epoxy. Read More

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