• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.5
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• pp.426-433
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• 2008

We first demonstrated simultaneous patterning and passivation of P3HT active layer with photosensitive PVA. The passivation layers were obtained by annealing the organic layers after developing PVA and subsequent over-etching the P3HT layer. The fabricated OTFTs were electrically characterized. The OTFTs exhibited the mobility of ${\sim}5.9{\times}10^{-4}\;cm^2/V{\cdot}s$ and on/off current ratio of ${\sim}10^4$. After passivation, the results showed the extended lifetime of ${\sim}250$ hours with photosensitive PVA layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.450-451
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• 2007

Dot-patterned carbon nanotube (CNT) emitters with excellent field emission properties were fabricated using photosensitive CNT paste. We carried out a parametric study on the compositions and the fabrication processes of the paste, in particular, by ball milling CNTs, which were optimized in terms of dot shapes and their field emission characteristics. The ball milling process improved the field emission current of the dot-patterned CNT emitters several times higher than that of the non-milled paste.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.145-153
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• 1996

Naphthoquinone-1,2-diazide-5-sulfonyl[NDAS] derivatives members of quinone diazide compound that are utilizable as photosensitive polymer material were synthesized, and photoresist were prepared by mixing these derivatives with m-cresol novolak(a matrix resin) at various weight ratios. Photosensitive characteristics of photoresist were studied by examining UV and IR, relative sensitivity using a Gray scale method, and SEM to analyze if they can be used as photosensitive material in printing process. Experimental results showed that, by UV, NDAS derivatives were photoconverted and developer-soluble photoresist were produced. The mixing ratio of 1:4(by mass) of NDAS+p-ydroxybenzophenone+sensitizer and m-cresol novolak gave rise to the highest dissolution rate. In addition, photoresist obtained at this condition resulted in the most superior sensitivity and contrast.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.5
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• pp.351-355
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• 2001

Via for achieving reliable fabrication of MCM(Multichip Module) substrate was formed on photosensitive BCB layer. The MCM substrate consists of photosensitive BCB(Benzocyclobutene) interlayer dielectric and copper conductors. In order to form the vias in the photosensitive BCB layer, the process of forming the BCB layer and its via forming plasma etch using C$_2$F$\_$6//O$_2$ gas were evaluated. The thickness of the BCB layer after hard bake was shrunk down to 40% of the original. The resolution of vias formed on the BCB was 15㎛ and the slope after develop was 85 degree. AES analysis was done on two vias, one is etched in C$_2$F$\_$6/O$_2$ gas and the other isnot etched. On the via etched in C$_2$F$\_$6//O$_2$, native C was detected and the amount of native C was reduced after Ar sputter. On the via not etched in C$_2$F$\_$6//O$_2$, organic C was detected. As a result of AES, BCB residue was not removed by Ar sputter, so plasma etch is necessary for achieving reliable vias.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.99-102
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• 2000

Via for achieving reliable fabrication of MCM-D substrate was formed on the photosensitive BCB layer. MCM-D substrate consists of photosensitive BCB(Benzocyclobutene) interlayer dielectric and copper conductors. In order to form the vias in photosensitive BCB layer, the process of BCB and plasme etch using $C_2$F$_{6}$ gas were evaluated. The thickness of BCB after soft bake was shrunk down to 60% of the original. AES analysis was done on two vias, one is etched in $C_2$F$_{6}$ gas and the other is non etched. On via etched in $C_2$F$_{6}$, native C was detected and the amount of native C was reduced after Ar sputter. On via non etched in $C_2$F$_{6}$, organic C was detected and amount of organic C was reduced a little after Ar sputter. As a result of AES, BCB residue was not removed by Ar sputter, so plasma etch is necessary for achieving reliable via.ble via.

• Macromolecular Research
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• v.8 no.4
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• pp.172-178
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• 2000

We synthesized polymethacrylate and polyurethane bearing a photosensitive azobenzene chromophore. Photo-induced birefringence of the thin film was observed under a linearly polarized light(λ = 532 nm). Dynamic behaviors of birefringence in two polymers were investigated in terms of the rate constants of growth and decay. An induced dichroism was observed from polarized UV-VIS absorption spectroscopy. Layers of two photosensitive polymers were used for aligning liquid crystal (LC) molecules instead of one of the rubbed polyimide layers in the conventional twisted nematic cell. For producing homogeneous alignment of a nematic LC molecule, a linearly polarized light was exposed to the films of two polymers. The stability of the LC alignment upon the linearly polarized light exposure was also studied.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.5
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• pp.474-480
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• 2008

In order to make full color cholesteric displays, color filter-less R, G, B sub-pixel structured cholesteric LC cells have been studied. To make R, G, B colors, UV induced pitch variant chiral dopant was added to cholesteric LC mixtures. The concentration of the photo-sensitive chiral dopant was adjusted so that the initial state showed blue color and the color was changed from blue to green and red with increase of UV irradiation to the cholesteric cells. To prevent the mixing of R, G, B reflective sub-pixel liquid crystals, separation walls were formed using negative photo resister in boundary area between sub-pixels, Through the optimization of the material concentrations and UV irradiation condition, vivid R, G, B colors were achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.369-369
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• 2007

ZnO film has been investigated during several decades because it has excellent optical property like a transmittance among the range of visible light for using transparent conducting oxide (TCO) films. But ZnO film has not enough conductivity for applying to TCO devices. Therefore we synthesized platinum nanoparticles and they incorporated into ZnO due to improve the electrical property of ZnO film by sol-gel synthesis method. Also, we fabricated photosensitive ZnO thin film containing Pt nanoparticles by sol-gel process and spin-coating for using photochemical solution deposition. Photosensitive ZnO film could carry out the direct-pattern which allow the etching process to be convenient. The optical and electrical properties of ZnO film with or without various atomic percent of Pt nanoparticles annealed at various temperatures were investigated by using UV-Vis spectroscopy and 4-point probe method, respectively. We characterized the ZnO thin film containing Pt nanoparticles using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy.

• Journal of the Korean Applied Science and Technology
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• v.14 no.2
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• pp.27-34
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• 1997

Naphthoquinone-1,2-diazide-5-sulfonyl [NDS]derivatives members of Quinone diazide compound that are utilizable as photoresist for printing plate were synthesized, and photoresist were prepared by mixing these derivatives with a matrix resin(PF, CF) at various weight ratios. Photosensitive characteristics of photoresist were studied by Gray scale method, and SEM to analyze if they can be used as photosensitive material in a printing plate. Experimental results showed using IR, UV, NDS derivatives were photoconverted and developer-soluble photoresist were produced. Photoresist in the mixing ratio of 1:4 of NDS[II] and CF resin gave rise to the highest dissolution rate. In addition, photoresist obtained at this condition resulted in the most superior sensitivity.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.10 no.1
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• pp.55-62
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• 2004

Synthesis of poly[N-(formyloxyphenyl)maleimide](PFOMI) as photopolymer were investigated with various kinds of photosensitive groups. Generally, photopolyimide have some deficiencies in solubility, sensitivity, reserve stability of the photosensitive solution, and the precision of image pattern. The study has been required on those polymers which have high glass transition temperature and photo efficiency, and low dielectricity. The existing condensation resins require high curing temperature and perfect elimination of subreacted materials that are produced during the process after irradiation and various membrane damages such as the deformation and contraction in image pattern cure. In this study poly[N-(hydroxyphenyl)maleimide](PHPMI) was synthesized. The PHPMI were analyzed by H-NMR and FT-IR. The measured number average molecular weight of PHPMI was produced was $1.06{\times}10^4$. Poly[N-(formyloxyphenyl)maleimide](PFOMI) as a type of photo-Fries rearrangement was synthesized by NHPMI and formic acid followed by radical polymerization. PFOMI was analyzed by FT-IR, and photocharacteristics was investgated by UV spectra and FT-IR before and after UV irradiation. Based on the image characteristics of PFOMI measured from optical micrographs, it was formed that the resolution of positive type PFOMI was $0.5{\mu}m$.