• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.218-222
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• 2021

Wearable multi-sensors based on nanocrystals have attracted significant attention, and studies on patterning technology to implement such multi-sensors are underway. Conventional patterning processes may affect material properties based on high temperatures and harsh chemical conditions. In this study, we developed an inkjet printing technique that can overcome these drawbacks through the application of patterning processes at room temperature and atmospheric pressure. Nanocrystal-based ink is used to adjust properties efficiently. Additionally, the viscosity and surface tension of the solvents are investigated and optimized to increase patterning performance. In the patterning process, the electrical, electrothermal, and electromechanical properties of the nanocrystal pattern are controlled by the ligand exchange process. Experimental results demonstrate that a multi-sensor with a temperature coefficient of resistance of 3.82 × 10^-3 K^-1 and gauge factor of 30.6 can be successfully fabricated using one-step inkjet printing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.3
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• pp.209-216
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• 2008

The application of focused ion beam (FIB) depends on the optimal interaction of the operation parameters between operating parameters which control beam and samples on the stage during the FIB deposition process. This deposition process was investigated systematically in C precursor gas. Under the fine beam conditions (30kV, 40nm beam size, etc), the effect of considered process parameters - dwell time, beam overlap, incident beam angle to tilted surface, minimum frame time and pattern size were investigated from deposition results by the design of experiment. For the process analysis, influence of the parameters on FIB-CVD process was examined with respect to dimensions and constructed shapes of single and multi- patterns. Throughout the single patterning process, optimal conditions were selected. Multi-patterning deposition were presented to show the effect of on-stage parameters. The analysis have provided the sequent beam scan method and the aspect-ratio had the most significant influence for the multi-patterning deposition in the FIB processing. The bitmapped scan method was more efficient than the one-by-one scan type method for obtaining high aspect-ratio (Width/Height > 1) patterns.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.658-659
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• 2008

Numerical simulation is performed for a microdroplet deposition on the pre-patterned micro-structure. The liquid-air interface is tracked by level set method improved by incorporating the ghost fluid approach based on a sharp-interface representation. The method is further extended to treat the contact angle condition at an immersed solid surface. The present computation of a patterning process using microdroplet ejection demonstrates that the multiphase characteristics between the liquid-gas-solid phases can be used to overcome the patterning error.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.1
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• pp.28-38
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• 2009

Numerical simulation is performed for microdroplet deposition on a pre-patterned micro-structure. The liquid-air interface is tracked by a level-set method, which is improved by incorporating a sharp-interface modeling technique for accurately enforcing the matching conditions at the liquid-gas interface and the no-slip condition at the fluid-solid interface. The method is further extended to treat the contact angle condition at an immersed solid surface. The present computation of a patterning process using microdroplet ejection demonstrates that the multiphase characteristics between the liquid-gas-solid phases can be used to improve the patterning accuracy.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.144.2-144.2
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• 2013

With the synthesis of graphene sheets as large-scale and high quality, it is essentially important to develop suitable graphene patterning process for future industrial applications. Especially, transfer or patterning method of CVD-grown graphene has been studied. We report simple soft lithographic process to develop easily applicable patterning method of large-scale graphene sheets by using chemically functionalized polymer stamp. Also important applications, the prototype capacitors with graphene electrode and commercial polymer dielectrics for the electrostatic-type touch panel are fabricated using the developed soft lithographic patterning and transfer process.

• 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.

• Laser Solutions
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• v.12 no.4
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• pp.1-5
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• 2009

Conventional patterning based on wet-process for multi-layered film is a relatively complex and costly process though it is a necessary step for fabrication of TFT-LCD module. Recently, a direct pattering by laser has been studied because it is low cost and simple process compared to the wet process. In this work, the selective removal process of multi-layered film (polyimide/indium tin oxide/glass) is studied by modeling the thermal and mechanical behavior for multi-layered structure. Especially, the effects of thickness of polyimide layer are examined.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.151-154
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• 2007

We demonstrate a novel selective patterning process of a semiconducting polymer for channel regions to fabricate an array of organic thin-film transistors (OTFTs). This process is applicable for various organic films over large area. A reflective liquid crystal display based on the OTFT array was produced using the selective patterning through a wettability control.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.122-128
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• 2016

The Biosensor biosensor pattern was developed by via an EHD (electro-hydro-dynamics (EHD) patterning process that was performed under atmospheric pressure at room temperature in a single step. The drop diameter was smaller than nozzle diameter and applied high viscosity conductive ink was applied in the EHD patterning method to provide a clear advantage over the piezo and thermal inkjet printing techniques. The Biosensor's biosensor's micro electrode pattern was printed by via a continuous EHD patterning method using 3three- type types of control parameters parameter (input voltage, patterning speed, nozzle pressure). High viscosity (1000 cps) conductive ink with 75 wt% of silver nanoparticles was used for experimentation. The incremental result of impedance of biosensor impedance was measured between the antibody ($10ug{\mu}g/ml$) to spore (0.1 ng/ml, 10 ng/ml, and $1ug{\mu}g./ml$) reaction at frequency 493 MHz frequency.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.750-757
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• 2002

Self-patterning of thin films using photosensitive sol solution has advantages such as simple manufacturing process compared to photoresist/dry etching process. In this study, ferroelectric $Sr_{0.9}Bi_{2.1}Ta_2O_9$ thin films have been prepared by spin coating method using photosensitive sol solution. Strontium ethoxide, tertramethylheptanedionato bismuth and tantalum ethoxide were used as starting materials. As UV exposure time to the SBT thin film increased, the UV absorption peak intensity of metal ${\beta}$-diketonate decreased due to reduced solubility by M-O-M bond formation. Solubility difference by UV irradiation on SBT thin film allows to obtain a fine patterning of thin film. Also, The ferroelectric properties of the UV irradiated SBT thin films were superior to those of the no-UV irradiated films.