Pulsed Laser Drilling of Engineering Plastic Films to Fabricate Through-Hole Membranes for Print-and-Imprint Method

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To understand the phenomenon in which shear stress increases in nanogaps between mold and substrate surfaces during alignment in ultraviolet (UV) nanoimprinting, we investigate the liquid advancement of UV-curable droplets on modified silicon surfaces. The droplets are pressed with a flat modified surface of a synthetic quartz mold, and the transformed droplets are cured individually. Subsequently, the mold is detached and the shapes of the transformed droplets are observed. Scanning electron microscopy is performed to determine whether the transformed shapes are affected by the pressing force and holding time under a fixed applied force. The areas on which the droplets spread on the modified silicon substrates are almost independent of the pressing force and holding time, whereas the thickness of the surface silicon oxide layer affects the liquid advancement of the UV-curable droplets sandwiched between the modified mold and substrate surfaces in the nanogaps.

Section: Methodsmentioning

confidence: 99%

Effect of thickness of surface silicon oxide on liquid advancement in nanogaps between synthetic quartz mold and silicon substrate surfaces in UV nanoimprinting

Nakagawa,

Onuma,

Niinomi

et al. 2024

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“…The details of the optical system are described in our former paper. 35) A polyimide film surface to contact a substrate surface was photo-oxidized using a UV/ozone cleaner. The photo-oxidized surface was coated with a solution of FAS13 (0.5 g) and toluene (10 g) using a silicon spatula and subsequently dried in an ambient atmosphere.…”

Section: Laser-drilled Screen Printingmentioning

confidence: 99%

Selecting adhesive molecular layers with matched surface free energy and chemisorption for shape-fixed UV-cured thin films fabricated by laser-drilled screen printing and UV nanoimprinting

Nakagawa

Kawasaki

Onuma

et al. 2023

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This study investigates the importance of surface free energy and chemisorption of substrates for formation of a UV-cured thin film corresponding to a residual layer in UV nanoimprint lithography. Silicon substrate surfaces were modified with binary molecular layers which were prepared through photo-oxidation of a monomer-repelling monolayer and implantation of a reactive surface modifier with an acrylate polymerizable group. Laser-drilled screen printing enabled the placement of droplets of high-viscosity dimethacrylate UV-curable liquid on the modified substrates. UV nanoimprinting with a modified flat mold surface allowed the formation of UV-cured films with a square shape and a sub-100 nm thickness. The thickness of the UV-cured film was tuned precisely in the case of the substrate showing almost the same surface free energy value as the mold surface. The comparison with and without the reactive surface modifier revealed that the chemisorption was essential for the film formation on the substrates.

“…The average diameters increased in the order of poly(ether ether ketone) (PEEK) ≈ poly(ethylene terephthalate) (PET) < polyimide (PI) < poly(phenylene sulfide) (PPS) at identical repetition rates because of absorption at the laser emission wavelength. 27) PET, PPS, and PEEK formed heataffected zones around the edges of the though holes by laser drilling at a high repetition rate of 50 kHz. A comparison of the engineering plastic films indicates that the polyimide film is suitable for through-hole stencil masks in screen printing because of the laser-drilled performance without heat-affected zones in addition to its chemical, thermal, and mechanical properties.…”

Section: Tuning the Diameters Of Through Holes On Laserdrilled Stenci...mentioning

confidence: 99%

Micro-print and nano-imprint methods combining laser-drilled screen printing and ultraviolet nanoimprint lithography: a review

Nakagawa

2022

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Ultraviolet (UV) nanoimprint lithography consists of molding–demolding and lithographic etching processes, which enable the shape transfer of molded resist patterns to underlying substrate surfaces. UV nanoimprint lithography has been applied in various fields, including optics, electronics, biology, and energy engineering. An important key to shape transfer through resist masks is to level the thicknesses of thin residual layers. To solve this issue, the region-selective placement of UV-curable droplets on a substrate is effective for leveling the thickness of the residual layer regardless of the differences in mold pattern density. Herein, we developed laser-drilled screen printing that allows the quantitative placement of high-viscosity UV-curable liquids on substrate surfaces via screen printing using a polyimide through-hole stencil mask prepared via ultrashort-pulse laser drilling. This review explains the practical demonstrations of UV nanoimprint lithography involving laser-drilled screen printing: nano/micro fabrication of Au split ring resonators, Au four-terminal electrodes, and silicon line patterns.