• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.76-76
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• 2007

Several kinds of photo-chromic polymers containing push-pull structure were synthesized and investigated on optical patterning by photo-induced surface relief gratings (SRG) technique. The azobenzene segment was introduced as a functional group for a photo-triggered tran-cis isomerization. Consequently, we have fabricated micro-size regular pattern by one-step process without photo-mask.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.369-372
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• 2004

Photo-induced surface alignment is charming as a non-contact photo-patternable alignment technology which can be used in the next generation of displays, such as large area, multi-domain. For decades, many polymer film have been investigated and developed to be used in the photo alignment. Among these photoreactive materials, recently developed polyimide, Chloromethylated Polyimide(CMPI) now became the focus of interests in this area because of its high photosensitivity and superior thermal stability. In this report, we present micro patterning method to form the nanoscale structure by Mask-Less laser patterning using this CMPI film and NSOM probe.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.503-507
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• 2002

Mask manufacturing is a high COC and COO process in developing of semiconductor devices, because of the mass production tool with high resolution. Direct writing has been thought to be one of the patterning method to cope with development or small-lot production of the device. This study focused on the development of the direct, mastless patterning process using stereolithography tool for the easy and convenient application to micro and miso scale products. Experiments are utilized by three dimensional CAD/CAM as a mask and photo-curable resin as a photo-resist in a conventional stereo-lithography apparatus. Results show that the resolution of the pattern was achieved about 300 micron because of complexity of SLA apparatus settings, inspite of 100 micro of inherent resolution. This paper concludes that photo resist and laser spot diameter should be adjusted to get finer patterns and the proposed method is significantly feasible to mastless and low cost patterning with micro and miso scale.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.303-303
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• 2007

Photo-imageable thick-film lithography technology was developed for the fabrication of embedded passives such as inductors and capacitors. In this study, photo-imageable dielectric and conductor pastes have apoted a negative type. Sodalime glass wafer, alumina substrate and zero-shrinkage LTCC green tapes were used as substrates. In result, The lithographic patterns were designed as lines and spaces for conductor material, or via-holes for ceramic, LTCC, materials. The scattering and reflection of UV-beam on the substrate had negative effects on fine patterning. The patterning performance was varied with the exposing and developing process conditions, and also varied with the substrate materials. Fine resolution of less then $50/50{\mu}m$ in line and space was obtained, which is difficult in screen printing method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.395-396
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• 2008

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.186-189
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• 2001

The main method in micro-etching process, used in manufacturing semiconductors, electronic components, circuits, is Photo Masking method that exposes and develops on the photo-sensitivity solutions or films. This method enables one to process highly precisely, $\pm$0.03 mm in end line location area. But this has limits in a high speed / wide width process, difficulties in endless masking, and the problem of high price. We have developed the direct masking method to make use of Gravure printing, widely used in grocery packing sheet printing. We made cylinder tools to influence the masking quality by laser stream process. We have confirmed that the end line location accuracy in the line width of the product is improved from 0.12 mm to $\pm$0.07 mm level, after etching process.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1419-1420
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• 2005

We have synthesized a photo patternable blue lightemitting polyfluorene (PF) derivative containing cross-linkable oxetane units. Poly(9,9-bis-(4-octyloxyphenyl)- fluorene-2,7-diyl-alt-9,9-bis-((3-hexyloxy-3'- ethyl)-oxetane)-fluorene-2,7-diyl) has been synthesized by Suzuki coupling polymerization. The relationship between patterning property and several variables such as the intensity of the exposed UV light, the concentrations of additives, has been studied by using optical microscope UV/visible spectroscopy, photoluminescence and scanning electron microscope (SEM). We obtained fine patterns with 10 mm resolution using the polymer film after exposure and development. This patterning method using conjugated polymers can be applicable to make fine pixels for PLEDs and OFETs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.191-191
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• 2007

By employing a photo-sensitive PVA as a photoresist, we first demonstrated simultaneous patterning and passivation of P3HT active layer. The passivation layers were obtained by annealing the organic layers after developing PVA and over-etching the P3HT layer. The fabricated OTFTs were electrically characterized. The OTFTs after the passivation exhibited the field-effect of ${\sim}5.9{\times}10^{-4}cm^2/V{\cdot}s$, on/off current ratio of ${\sim}10^3$. The value of OTFTs a little degradation with time in air but it appeared different unpassivated OTFT.

• Macromolecular Research
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• v.17 no.10
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• pp.791-796
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• 2009

An electrochemically and photochemically polymerizable monomer, 2-((2,3-dihydrothieno[3,4-b] [1,4]dioxin-2-yl)methoxy)ethyl methacrylate (EDOT-EMA), was explored for patterning of poly(3,4-ethylenedioxythiophene) (PEDOT) via side chain cross-linking. The polymer from EDOT-EMA was deposited electrochemically to produce polymeric EDOT (PEDOT-EMA), which was directly photo-patterned by UV light as the side EMA groups of PEDOT-EMA were polymerized to give cross-linked EMA (PEDOT-PEMA). Absorption and FTIR studies of the UV-exposed film (PEDOT-PEMA) indicated that the photo-patterning mainly originated from the photo cross-linking of the methacrylates in the side-chain. After irradiation of the film, the conductivity of the irradiated area decreased from $5.6{\times}10^{-3}$ S/cm to $7.2{\times}10^{-4}$ S/cm, possibly due to bending of the conductive PEDOT channel as a result of the side chain cross-linking. The patterned film was applied to a solid state electrochromic (EC) cell to obtain micro-patterned EC cells with lines up to 5 ${\mu}m$ wide.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.1
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• pp.21-26
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• 2021

Single-layer graphene is grown directly on Ti-buffered SiO2 at 100℃. As a result of the AFM measurement of the Ti buffer layer, the roughness of approximately 0.2 nm has been improved. Moreover, the Raman measurement of graphene grown on it shows that the D/G intensity ratio is extremely small, approximately 0.01, and there are no defects. In addition, the 2D/G intensity ratio had a value of approximately 2.1 for single-layer graphene. The sheet resistance is also 89 Ω/□, demonstrating excellent characteristics. The problem was solved by using graphene and a lift-off patterning method. Low-temperature direct-grown graphene does not deteriorate after the patterning process and can be used for device and micro-patterning research.