• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.231-236
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• 2005

To investigate the electrical properties at the single grainboundary of ZnO varistors, micro-electrodes were fabricated on the surface which was polished and thermally etched. Our micro-electrode had 2000 $\AA$ silicon nitride layer between micro-electrode and ZnO surface. This layer was deposited by PECVD and etched by RIE after photoresistor pattering process using by mask 1. The metal patterning of micro-electrodes used lift-off method. We found that the breakdown voltage of single grainboundary is about 3.5∼4.2 V at 0.1 mA on I-V curves. Also, capacitance-voltage measurement at single grainboundary gave several parameters( $N_{d}$, $N_{t}$, $\Phi$$_{b}$, t) which were related with grainboundary.ary.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.366-370
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• 1997

This paper descibes a micro groove machining process on the polyurethane biopolymer by KrF excimer laser. To investigate the etch charcteristics of polyurethane biopolymer quantitatively,laser system for ablation was installed with high precison moter and then polymer ablation experiment, in which paramteters were fluence,pulse repetition rate,numbers of pulses and assist gas, was carred out. In this experiment, we found out that the value of critical energy density for ablation is 30mJ/cmsup2/ and the etching rate is more dependent on the pulse number and fluence than any other pamameter. Finally, we machined micro grooves for fiexibility as width 300.mu.m depth 100.mu.m and port for micro-devices mounting as length 100.mu.m width 300.mu.m depth .mu.m on the outer wallof polyurethane biopolymer tube which is used as medical device.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.138-145
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• 2006

An injection molding is necessary to mass-product for micro-nano system, so micro-nano mold must be developed for injection molding. The micro-nano mold has precision and strength to overcome a surround of injection. So in this paper, two methods were used. First, after etching the Al, Ni was electroplated in etched AI. The other, LIGA method was used. A temperature and thickness of Ni are important factors in these methods. So after fabrication, the simulation was processed to find optimal thickenss of Ni and temperature.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.110-116
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• 2011

The current study investigated the friction property of angle and width effect for micro-scale grooved crosshatch pattern on SKD11 steel surface against bearing steel using pin-on-disk type. The samples fabricated by photolithography process and then these are carry out the electrochemical etching process. We discuss the friction property due to the influence of a hatched-angle and a width of groove on contact surface. We could be explained the lubrication mechanism for a Stribeck curve. So It was found that the friction coefficient depend on an angle of the crosshatch on contact surface. It was thus verified that micro-scale crosshatch grooved pattern could affect the friction reduction. Also, it is play an important a width of groove to be improved the friction property. I was found that friction property has a relationship between a width and an angle for micro-grooved pattern.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.341-346
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• 2000

The effect of OTS(octadecyltrichlorosilane) SAM(self-assembled monolayer) on the micro-adhesion has been studied. OTS SAM was formed on the Si(100) surface and SPM (scanning probe microscope) tips with different radius of curvature were fabricated by a series of masking and etching processes. Pull-off forces of different tips on Si and OTS SAM surfaces were measured by SPM in different relative humidities. The surface of OTS SAM was changed to hydrophobic surface and the micro-adhesion force of OTS SAM was lower than that of pure Si. As the tip radius of curvature and the relative humidity increased. the micro-adhesion force increased. Based on the test results. the main parameter affected to the micro-adhesion was absorbed humidity on the surface.

• KSTLE International Journal
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• v.8 no.2
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• pp.26-28
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• 2007

Si(100) surfaces were topographically modified i.e. the surfaces were patterned at micro-scale using photolithography and DRIE (Deep Reactive Ion Etching) fabrication techniques. The patterned shapes included micro-pillars and microchannels. After the fabrication of the patterns, the patterned surfaces were chemically modified by coating a thin DLC film. The surfaces were then evaluated for their friction behavior at micro-scale in comparison with those of bare Si(100) flat, DLC coated Si(100) flat and uncoated patterned surfaces. Experimental results showed that the chemically treated (DLC coated) patterned surfaces exhibited the lowest values of coefficient of friction when compared to the rest of the surfaces. This indicates that a combination of both the topographical and chemical modification is very effective in reducing the friction property. Combined surface treatments such as these could be useful for tribological applications in miniaturized devices such as Micro-Electro-Mechanical-Systems (MEMS).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1194-1197
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• 2005

Micro nozzle is employed as a dynamic passive valve in micro fluidic devices. Micro nozzle array is used in micro droplet generation in bio-medical applications and propulsion device for actuating satellite and aerospace ship in vacuum environments. Aperture angle and the channel length of the micro nozzle affect its retification efficiency, and thus it is needed to produce micro nozzle precisely. MEMS process has a limit on making a micro nozzle with high-aspect ratio. Reactive ion etching process can make high-aspect ratio structure, but it is difficult to make the complex shape. Focused ion beam deposition has advantage in machining of three-dimensional complex structures of sub-micron size. Moreover, it is possible to monitor machining process and to correct defected part at simultaneously. In this study, focused ion beam deposition was applied to micro nozzle production.

• Journal of Integrative Natural Science
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• v.5 no.4
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• pp.211-215
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• 2012

Single-crystalline silicon nanowire arrays (SiNWAs) using electroless metal-assisted etchings of p-type silicon were successfully fabricated. Ag nanoparticle deposition on silicon wafers in HF solution acted as a localized micro-electrochemical redox reaction process in which both anodic and cathodic process took place simultaneously at the silicon surface to give SiNWAs. The growth effect of SiNWs was investigated by changing of etching times. The morphologies of SiNWAs were obtained by SEM observation. Well-aligned nanowire arrays perpendicular to the surface of the silicon substrate were produced. Optical characteristics of SiNWs were measured by FT-IR spectroscopy and indicated that the surface of SiNWs are terminated with hydrogen. The thicknesses and lengths of SiNWs are typically 150-250 nm and 2 to 5 microns, respectively.

• Transactions on Electrical and Electronic Materials
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• v.6 no.3
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• pp.87-90
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• 2005

$SiO_2$ via-hole etching with a high aspect ratio is a key process in fabricating ULSI devices; however, accumulated charge during plasma etching can cause etching stop, micro-loading effects, and charge build-up damage. To alleviate this concern, charge-up damage sensor was fabricated for the ultimate goal of real-time monitoring of accumulated charge. As an effort to reach the ultimate goal, fabricated sensor was used for electrical potential measurements of via holes between two poly-Si electrodes and roughly characterized under various plasma conditions using statistical design of experiment (DOE). The successful identification of potential difference under various plasma conditions not only supports the evidence of potential charge-up damage, but also leads the direction of future study.

• Transactions of Materials Processing
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• v.11 no.7
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• pp.601-607
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• 2002

Optically transparent materials such as fused silica, quartz and crystal have become important in the filed of optics and optoelectronics. Laser ablation continues to grow as an important technique for micromachining and surface modification of various materials, because many problems caused by direct contact between tools and workpiece can be avoided. Especially, laser ablation with excimer lasers enables fine micromachining of transparent materials such as fused silica, quartz and crystal, etc. In this study, laser-induced wet etching of fused silica in organic solution was conducted. KrF excimer laser was used as a light source and acetone solution of pyrene was used as etchant. Changing the number of laser pulses, micro holes of various depths are fabricated.