• Journal of Magnetics
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• v.13 no.2
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• pp.53-56
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• 2008

This study proposes a simple nano-patterning process for the fabrication of magnetic nanodot arrays on a large area substrate. Ni nanodots were fabricated on a large area (4 inches in diameter) Si substrate using the soft lithographic technique using self-assembled surface micelles of Polystyrene-block-Poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer formed at the air/water interface as a mask. The hexagonal array of micelles was successfully transferred to a Ni thin film on a Si substrate using the Langmuir-Blodgett technique. After ion-mill dry etching, a magnetic Ni nanodot array with a regular hexagon array structure was obtained. The Ni nanodot array showed in-plane easy axis magnetization and typical soft magnetic properties.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.612-615
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• 2003

Maskless laser patterning process is developed using 3rd harmonic Diode Pumped Solid State Laser with near visible wavelength of 355 nm. Photo-sensitive curable polymer is irradiated by UV laser and developed using polymer solvent to obtain quasi-3D patterns. We performed basic experiments for the various process conditions such as laser power, writing speed, laser focus, and polymer optical property to gain the optimal conditions. Experimentally, the patterns of trapezoidal shape were manufactured into dimension of 8${\mu}{\textrm}{m}$ width and 5.4${\mu}{\textrm}{m}$ height. This process could be applied to fabricate a single mode waveguide without expensive mask projection method.

• Laser Solutions
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• v.9 no.1
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• pp.17-23
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• 2006

The technologies of laser micromachining are changed toward more complex-micropatterning, from the micro circle-shaped hole drilling to the micro arbitrary-shaped hole drilling. In this paper, the fundamental experiments by using DPSS 3rd harmonic $Nd:YVO_4\;laser({\lambda}=355nm)$ were carried out in order to obtain the feasibility of flexible micropatterning by various fixed masks. Fixed masks and Galvano scanners were investigatde to make micro patterns. from these experimental results, micropatterns on PEN film were rapidly manufactured in large area.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1272-1273
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• 2009

We demonstrate conformal phosphor coating and patterning methods on light emitting diodes (LEDs) using image processing based optofluidic maskless lithography (IP-OFML) system in microfluidic channels. IP-OFML allows a real-time detection and dynamic mask generation for packaging of randomly dispersed microchips. Our system detects each chip by considering rotation of the chip through image processing regardless of their arrangement error. Therefore, it precisely packages the chip making conformal polymer layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.511-514
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• 2000

This work aimed to develop ITO (Indium Tin Oxide) thin films ablation with a KrF Eximer laser required for the application in flat panel display, especially patterning into small geometry on a large substrate area. The threshold fluence for ablating ITO on glass substrate is about 0.1 J/cm$^2$. And its value is much smaller than using third harmonic Nd:YAG laser. Through the optical microscope measurement the surface color of the damaged ITO is changed into dark brown and irradiated spot is completely isolated form the undamaged surroundings by laser light. The XPS analysis showed that the relative surface concentration of Sn and In were essentially unchanged (In :Sn=5:1) after irradiating Eximer laser. Using aluminium mask made by second harmonic Nd:YAG laser the ITO patterning is carried out.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.2
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• pp.38-43
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• 2019

Electrochemical etching is a popular process to apply metal patterning in various industries. In this study, the electrochemical etching using a patterned copper layer was proposed to fabricate multilayered structures. The process consists of electrodeposition, laser patterning, and electrochemical etching, and a repetition of this process enables the production of multilayered structures. In the fabrication of a multilayered structure, an etch factor that reflects the etched depth and pattern size should be considered. Hence, the etch factor in the electrochemical etching process using the copper layer was calculated. After the repetition process of electrochemical etching using copper layers, the surface characteristics of the workpiece were analyzed by EDS analysis and surface profilometer. As a result, multilayered structures with various shapes were successfully fabricated via electrochemical etching using copper layers.

• Journal of the Korean Magnetics Society
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• v.23 no.4
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• pp.126-129
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• 2013

We have fabricated an ordered Ni nanodot structure using an alumina mask prepared via 2-step anodization technique under phosphoric acid. We have formed a porous structure with average pore size of 279 nm on $2{\mu}m$ thick alumina film and the thermal deposition of thin Ni film though the mask led to the formation of ordered Ni nanodot structure with an average dot size of 293 nm, following the pore structure on the mask. We further investigated the magnetic properties of the nanodot structure by measuring the hysteresis curve at room temperature. When compared to the magnetic properties of a continuous Ni film, we observed the decrease in the squareness and the increase in coercivity along the magnetization easy axis, due to the isolated nanodot structure. Our study suggests that the ordered nanodot structure can be easiy fabricated with thin film deposition technique using anodized alumina mask as a mask.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.60-67
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• 1999

Micro-fabrication techniques such as lithography and LIGA processes usually require large investment and are suitable for mass production. Therefore, there is a need for a new micro-fabrication technique that is flexible and more cost effective. In this paper a novel, economical and flexible method of producing micro-pattern on silicon wafer is presented. This method relies on selective removal of mask by mechanical cutting. Then micro-pattern is produced by chemical etching. V-shaped grooved of about 3 ${\mu}m$ wide and 2 ${\mu}m$ deep has been made on ${SiO_2}m$ coated silicon wafer with this method. This method may be utilized for making microstructures in MEMS application at low cost.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.245-250
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• 2011

A high-resolution shadow mask, a nanostencil, is widely used for high resolution lithography. This high-resolution shadowmask is often fabricated by a combination of MEMS processes and focused ion beam (FIB) milling. In this study, FIB milling on 500-nm-thin SiN membrane was tested and characterized. 500 nm thick and $2{\times}2$ mm large membranes were made on a silicon wafer by micro-fabrication processes of LPCVD, photolithography, ICP etching and bulk silicon etching. A subsequent FIB milling enabled local membrane thinning and aperture making into the thinned silicon nitride membrane. Due to the high resolution of the FIB milling process, nanoscale apertures down to 60 nm could be made into the membrane. The nanostencil could be used for nanoscale patterning by local deposition through the apertures.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.869-875
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• 1996

In this article the effects of process parameters of inductively coupled plasma etching with $SF_6$ /$N_2$/Ar mixture gas and mask materials on the etched profile of W were investigated. While the etched profile was improved by $N_2$-addition, low working presure, and reduced $SF_6$ flow rate, the etching selectity (W against SAL resist) was decreased. Due to the difficulty of W etching with single layer resist, sputter deposited $Al_2O_3$ film was used as a hardmask. Reduction of required EB resist thickness through $Al_2O_3$ mask application could reduce proximity effect during e-beam patterning, but the etch anisotropy was degraded by decreased sidewall passiviation effect.