• Journal of the Microelectronics and Packaging Society
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• v.10 no.2
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• pp.1-5
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• 2003

In this project, the efficiency of localized heating for micro systems packaging is developed by using a forced potential scheme microheater. Less than 0.2 Mpa contact pressure was used for bonding with a 200 mA current input for $50{\mu}m$ width, $2{\mu}m$ height and $8mm{\times}8mm$, $5mm{\times}5mm$, $3mm{\times}3mm$ sized phosphorus-doped poly-silicon microheater. The temperature can be raised at the bonding region to $800^{\circ}C$, and it was enough to achieve a strong and reliable bonding in 3 minutes. The IR camera test results show improved uniformity in heat distribution compared with conventional microheaters. For performing the gross leak check, IPA (Isopropanol Alcohol) was used. Since IPA has better wetability than water, it can easily penetrate small openings, and is more suitable for conducting a gross leak check. The pass ratio of bonded dies was 67%, for conventional localized heating, and 85% for our newly developed FP scheme. The bonding strength was more than 25Mpa for FP scheme packaging, which shows that FP scheme can be a good candidate for micro-scale hermetic packaging.

• Polymer(Korea)
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• v.24 no.6
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• pp.737-743
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• 2000

Polyquinonediimines (PQDI) which have stable structure on heat and contains mono-azobenzene in the side chain were synthesized by means of condensation polymerization under TiCl$_4$. The synthesized monomers and polymers were identified by FT-IR, $^1$H-NMR, and elementary analysis. Especially, PQDI was comfirmed by the double-bonding peak of >C=N appeared near 1625 $cm^{-1}$ / by means of FT-IR spectrum. PQDI containing mono-azobenzene group in both side chains wat not soluble in non-polar solvents at all but partially soluble in the polar solvents having small dielectric constant, and dissolved in the strong acid such as sulfuric acid and $CH_3$SO$_3$H. Molecular weight distribution of PQDI measured by GPC showed 1.74. It was confirmed through X-ray diffraction analysis that the polymer was partially crystalline at the low angle region, but amorphous after heat treatment at 1$25^{\circ}C$. The glass transition temperature (T$_{g}$ ) of synthesized polymer was measured as 1$25^{\circ}C$ by differential scanning calorimetry. The SHG value for $\chi$$^{(2)}$ after poling at 1$25^{\circ}C$ was 8.6 pm/V (λ=1.542 ${\mu}{\textrm}{m}$). The SHG value slowly decreased with time from the start but appeared temporal stability after 100 hours.

• Polymer(Korea)
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• v.25 no.4
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• pp.496-502
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• 2001

Thermally stable polyquinonediimines(PQDI) containing di-azobenzene in the side chain were synthesized by means of condensation polymerization under $TiCl_4$. The synthesized monomers and polymers were identified by FT-IR, $^1H-NMR$, and elemental analysis. Especially, the polymerization of PQDI was confirmed by the double-bonding peak of >C=N appearing near 1625cm$^{-1}$ in FT-IR spectrum. PQDI with di-azobenzene group in one side chain was insoluble in methanol, acetone and non-polar solvents having big dielectric constant, but had good solubility in polar solvents having small dielectric constant. Molecular weight distribution of PQDI measured by GPC was 1.38. It was confirmed to be amorphous polymer through X-ray diffraction by the appearance of the halo in case of PQDI containing di-azobenzene in the side chain. The glass transition temperature ($_g$) of synthesized polymer was measured to be 116$^{\circ}C$ by differential scanning calorimetry. The SHG value for ${\chi}^{(2)}$ was 1.2 pm/V (${\lambda}$ = 1.542 ${\mu}$m). The SHG value slightly decreased in an early stage but showed temporal stability after 20 hours.

• Korean Journal of Optics and Photonics
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• v.33 no.1
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• pp.28-34
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• 2022

We study through computational simulation the focal performance of an infrared (IR) Fresnel lens, composed of a multilayer-graphene zone plate formed under a graphene electrode. Here the Fermi level E_F of the patterned multilayer graphene is adjusted by the overlying graphene electrode. The Fresnel lens effect, with respect to the reflectance contrast between the graphene electrode and the 8-layer graphene zone plate placed on a glass substrate, has been analyzed over a broad wavelength range from 4 to 30 ㎛. As the optimal wavelength of 8 ㎛ (considering the reflectance and the reflectance-contrast ratio) is incident upon the Fresnel lens with a focal length of 240 ㎛, the focal intensity is enhanced by a factor of 4.3 as the E_F of multilayer graphene increases from 0.4 eV to 1.6 eV, and is improved by a factor of 5.8 as the number of graphene layers increases from two to eight. As a result, an all-graphene-based IR Fresnel zone-plate lens, exhibiting multifocal function (240 ㎛ and 360 ㎛) according to the selected E_F, is proposed as an ultrathin lens platform.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.416-423
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• 2009

Statement of problem: The degree of light attenuation at the time of cementation of the PLV restoration depends on characteristics such as thickness, opacity and shade of the restorations, which interfere with light transmittance and, as a result, may decrease the total energy reaching the luting cement. Purpose: The purpose of this study was to compare the degree of conversion of light-cured resin cements measuring by FT-IR in regard to different thickness, light devices and curing time. Material and methods: In the control group, a clear slide glass (1.0 mm) was positioned between the light cured resin cement and light source. The specimens of ceramics were made with IPS Empress Esthetic. The ceramics were fabricated with varying thicknesses-0.5, 1.0, 1.5 mm with shade ETC1. Rely $X^{TM}$ Veneer with shade A3, light-cured resin cement, was used. Light-activation was conducted through the ceramic using a quartz tungsten halogen curing unit, a light emitting diode curing unit and a plasma arc curing unit. The degree of conversion of the light-cured resin cement was evaluated using FT-IR and OMNIC. One-way ANOVA and Tukey HSD test were used for statistical analysis ($\alpha$< .05). Results: The degree of conversion (DC) of photopolymerization using QTH and LED was higher than results of using PAC in the control group. After polymerization using QTH and LED, the DC results from the different ceramic thickness- 0.5 mm, 1.0 mm, 1.5 mm- did not show a significant difference when compared with those of control group. However, the DC for polymerization using PAC in the 1.5mm ceramic group showed significantly lower DC than those of the control group and 0.5 mm ceramic group (P<.05). At 80s and 160s, the DC of light-cured resin cement beneath 1.0 mm ceramic using LED was significantly higher than at 20s (P<.05). Conclusion: Within the limitation of this study, when adhering PLV to porcelain with a thickness between 0.5-1.5 mm, the use of PAC curing units were not considered however, light cured resin cements were effective when cured for over 40 seconds with QTH or LED curing units. Also, when curing the light cured resin cements with LED, the degree of polymerization was not proportional with the curing time. Curing exceeding a certain curing time, did not significantly affect the degree of polymerization.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.2
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• pp.56-59
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• 2001

Thin films of hydrogenated amorphous silicon (a-Si : H) of different compositions were deposited on Si(100) wafer and glass by RF plasma-enhanced chemical vapor deposition (PECVD). In the present work, we have investigated the effect of the If. power on the properties, such as optical band gap, transmittance and crystallinity, of crystalline silicon thin films. Raman data show that the material consists of an amorphous and crystalline phase for the co-presence of two peaks centered at 480 and 520cm$^{-1}$. X-ray spectra confirmed of crystallites with (111) orientation at 300w The transmittance of thin films was measured by UV-VIS spectrophotometer. In addition, Si-H chemical bondings were studied by Fourier Transform Infrared (FT-IR) spectroscopy.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.687-694
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• 2006

We report on the fabrication of organic-based flexible displays using an amorphous IZO anode grown at room temperature. The IZO anode films were grown by a conventional DC reactive sputtering on the polycarbonate (PC) substrate at room temperature using a synthesized IZO target in a $Ar/O_2$ ambient. Both x-ray diffraction (XRD) and high resolution electron microscope (HREM) examination results show that the IZO anode film grown at room temperature Is complete amorphous structure due to low substrate temperature. A sheet resistance of $35.6\Omega/\Box$, average transmittance above 90 % in visible range, and root mean spare roughness of $6\sim10.5\AA$ were obtained even in the IZO anode film grown on PC substrate at room temperature. It is shown that the $Ir(ppy)_3$ doped flexible organic light emitting diode (OLED) fabricated on the IZO anode exhibit comparable current-voltage-luminance characteristics as well as external quantum efficiency and power efficiency to OLED fabricated on conventional ITO/Glass substrate. These findings indicate that the IZO anode film grown on PC substrate is a promising anode materials for the fabrication of organic based flexible displays.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.5
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• pp.366-371
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• 2012

In this paper, fabricated by MEMS uncooled micro-bolometer detector for the study in the infrared sensitivity enhancement. Absorption layer SiOx-Metal series MDTF (metal-dielectric thin film) by high absorption rate and has a high thermal coefficient of resistance, low noise characteristics were implemented. Then MDTF were made in a vacuum deposition method. And MDTF for the analysis of the physical properties of silicon wafers were fabricated, TCR (temperature coefficient of resistance) value was made in order to measure the glass wafer and FT-IR (Fourier Transform Infrared spectroscopy) values were made in order to measure the germanium window. The analyzed results of MDTF -3 [%/K] has more characteristics of the TCR. And 8~12 um wavelength region close to 70% in the absorption characteristic.

• Textile Coloration and Finishing
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• v.27 no.2
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• pp.126-131
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• 2015

Silica-polyurethane hybrid breathable films were prepared and their breathabilities were assessed. Appropriately aggregated silica was prepared through sol-gel reaction of water glass and its particle size ranged 360~500nm. The polyurethane dispersion was prepared by the reaction of isophorone diisocyanate(IPDI) as diisocyanate and polytetramethylene glycol(PTMG) and dimethylol propionic acid(DMPA) as polyol, particle size ranging 30~120nm. The reaction between isocyanate and hydroxyl group to form urethane bonding was checked by the intensity of the stretch peak of isocyanate at $2270cm^{-1}$ in the FT-IR. The silica was incorporated into polyurethane dispersion and casted into film. It was shown that the incorporated silica(1~5wt.%) increased water vapour permeability of the films by 30~100%, and decreased the hydrostatic pressure by 10~40%. From the results, it could be concluded that the appropriate hybridization of silica can increase the breathability of polyurethane dispersion film, while minimizing the loss of hydrostatic pressure.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.1065-1068
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• 1998

On the study, The activated carbon assemblies(ACA) were prepared by activation of the coated glass mate(woven type) with phenolic resin at $700^{\circ}C$ under $N_2$ after drying and curing processes. Surface of the ACA was continuously modified with $N_2$, $CO_2$ or $NH_3$ at $700^{\circ}C$ for 2 hour for comparison of adsorptive characteristics between the ACA and commercial activated carbon cloth. The ACA showed high surface areas up to $2440\;m^2/g$ when converted into the coated carbon base, and the surface was investigated by FT-IR and XPS. The basic ACA modified with $NH_3$ displayed the efficient removal capability of $SO_2$, which is 75% of that in commercial activated carbon cloth. Therefore, it has proved the applicability of ACA as an inexpensive materials for Dry de-SOX system.