• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.92-96
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• 2019

In the presence of ${\mu}-tip$ embedded in a slot-die head for stripe coatings, there arises the capillary flow that limits an increase of the stripe density, which is required for the potential applications in organic light-emitting diode displays. With an attempt to suppress it, we have employed a computational fluid dynamics software and performed simulations by varying the ${\mu}-tip$ length and the contact angles of the head lip and ${\mu}-tip$. We have first demonstrated that such a capillary flow phenomenon (a spread of solution along the head lip) observed experimentally can be reproduced by the computational fluid dynamics software. Through simulations, we have found that stronger capillary flow is observed in the hydrophilic head lip with a smaller contact angle and it is suppressed effectively as the contact angle increases. When the contact angle of the head lip increases from $16^{\circ}$ to $130^{\circ}$, the distance a solution can reach decreases sharply from $256{\mu}m$ to $44{\mu}m$. With increasing contact angle of the ${\mu}-tip$, however, the solution flow along the ${\mu}-tip$ is disturbed and thus the capillary flow phenomenon becomes more severe. If the ${\mu}-tip$ is long, the capillary flow also appears strong due to an increase of flow resistance (electronic-hydraulic analogy). It can be suppressed by reducing the ${\mu}-tip$ length, but not as effectively as reducing the contact angle of the head lip.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.4
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• pp.149-154
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• 2004

This paper presents a silicon probe tip for vertical probe card application. The silicon probe tip was fabricated using MEMS technology such as porous silicon micromachining and deep- RIE (reactive ion etching). The thickness of the silicon epitaxial layers was 5 ${\mu}{\textrm}{m}$ and 7 ${\mu}{\textrm}{m}$, respectively. The width and length were 40 ${\mu}{\textrm}{m}$ and 600 ${\mu}{\textrm}{m}$, respectively. The probe structure was a multilayered structure and was composed of Au/Ni-Cr/Si$_3$N$_4$/n-epi layers. The height of the curled probe tip was measured as a function of the annealing temperature and time. Resistance characteristics of the probe tip were measured using a touchdown test.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.124-127
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• 2000

A new triode type Ti-silicided Si FEA(field emitter array) was realized by Ti-silicidation of Ti coated Si FEA and its field emission properties were investigated. In the fabricated device, the field emission properties through the unit pixel with $200{\mu\textrm{m}}{\times}200{$\mu\textrm{m}}$ tip array in the area of $1000{\mu\textrm{m}}{\times}1000{$\mu\textrm{m}}$ were as follows : the turn-on voltage was about 70V under high vacuum condition of $10^8Torr$, and the field emission current and steady state current degradation were about 2nA/tip and 0.3%/min under the bias of $V_A=500V\;and\;V_G=150V$. The low turn-on voltage and the high current stability during long term operation of the Ti silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• Korean Journal of Materials Research
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• v.10 no.4
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• pp.301-304
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• 2000

A new triode type Co-silicided Si FEA(field emitter array) was realized by Co-silicidation of Co coated Si FEA and its field emission properties were investigated. The field emission properties of the fabricated device through the unit pixel with $45{\times}45$ tip array in the area of $250{\mu\textrm{m}}{\times}250{\mu\textrm{m}}$ under high vacuum condition of $10^{-8}Torr$ were as follows : the turn-on voltage was about 35V and the anode current was about $1.2\mu\textrm{A}(0.6㎁/tip)$ at the bias of $V_A=500V\;and\; V_G=55V$. The fabricated device showed the stable electrical characteristics without degradation of field emission current for the long term operation except for the initial transient state. The low turn-on voltage and the high current stability of the Co-silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• 전자공학회논문지 IE
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• v.44 no.3
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• pp.1-5
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• 2007

A new field emission tip array was realized by Ti silicidation of Ti coated Si tip, which has long term durability, chemical stability, and high emission current density. The fabricated Ti silicided FE tip array under high vacuum condition of about $10^{-8}Torr$ shows that the turn-on voltage is about 40V and the emission current is about $69{\mu}A$ when the bias of 150V is applied between anode and cathode of $100{\mu}m$ distance.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1160-1163
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• 1999

In this study, we developed FE-tip lithography system that could apply to multi-tip system and did lithography using FE-tip. The software that control FE-tip lithography system, was proposed for acquiring more adaptive data to compensate the effect of fluctuation. We found that the fluctuation effect was reduced. The minimum line width was related to applied voltage and we observed a movement of Z-axis piezo stage to correct the error of this system. When FE current was 5nA, scanning speed was $3{\mu}m/sec$ and applied voltage was 200V, we made a line pattern which had minimum line width of 614 nm. If we reduce applied voltage to several decades and increase scanning speed to $20{\mu}m/sec$, it is possible to set the minimum line width of 100 nm. The proposed system can be easily applied to multi FE-tip lithography system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1495-1508
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• 1990

There are requirement of surface roughness in mechanical elements that has minute surface of several nm degree. When high precision surface roughness measurement is made with stylus type surface roughness measuring apparatus, measuring accuracy depend on the tip radius of diamond stylus. Therefore, ultra precision machining was accomplished using ion sputter machining in order to machining the stylus tip radius less than 0.5.mu.m, which is impossible through lapping machining. In this study, optimal machining condition for the ion sputter machining was obtained through the experiment under the various varing machinbing quantity and condition of diamond stylus. And as the result of applying this optimal condition, the good result was obtained that machining probability of stylus tip radius less than o.5.mu.m is 93%.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.256-259
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• 2008

An micro-probe tip must be manufactured using thin film to evaluate integrity of the semiconductor with narrow distance between pads. In this study, fatigue tests were performed for BeCu thin film which is used in micro-probe tip of semiconductor test machine. The thin film was manufactured by electro plating process, and the specimens were fabricated by wire-cut electric discharge method to make hour glass type specimen of $5000{\mu}m$ width, $29200{\mu}m$ length and $30{\mu}m$ thickness. The fatigue test of load control with 10Hz frequency was performed, in ambient environment. The fatigue cycles were tension-tension with mean stress, at stress ratio, R=0.1.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.9
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• pp.605-610
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• 2001

Electrostatic comb-drive microactuators with sub-micron gap were fabricated and tested. We designed and fabricated two type of electrodes which are rectangular and triangular tip. The fabricated microactuators with triangular tip resulted in the electrode gaps in the range of 0.55 ${\mu}{\textrm}{m}$~1.35 ${\mu}{\textrm}{m}$ Displacement of 1 ${\mu}{\textrm}{m}$ and electrostatic force of 2.3 $\mu$N were observed in a triangular-tip microactuator with 0.55 ${\mu}{\textrm}{m}$ gap when a DC drive voltage of 13 volts was applied. Measured 1st resonance frequency of microactuators was about 23 kHz.

• Journal of the Semiconductor & Display Technology
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• v.18 no.2
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• pp.6-10
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• 2019

In the presence of $\mu-tip$ for narrow stripe coating, there appears lateral capillary flow along the hydrophilic head lip because the $\mu-tip$ has some resistance to flow. It was known to be suppressed by increasing the contact angle of the head lip. In this paper, we have demonstrated by computational fluid dynamics(CFD) simulations that it can also be suppressed by the formation of micro-patterns on the shim and meniscus guide embedded into the slot-die head. To optimize the micro-patterned structure, we have performed simulations by varying the groove width, depth, and clearance. In the absence of micro-patterns, it is shown by experiment and simulation that the solution spreads to a distance of $1,300{\mu}m$ from the ${\mu}-tip$. In the presence of micro-patterns with the groove width and clearance of $50{\mu}m$, the distance the solution spreads is reduced to $260{\mu}m$. However, no further suppression in the capillary flow is observed with micro-patterns with the groove width of $40{\mu}m$ or less. It is also observed that the capillary flow is not affected by the groove depth if it is larger than $10{\mu}m$. We have shown that the distance the solution spreads can be reduced further to $204{\mu}m$ by coating a hydrophobic material (contact angle of $104^{\circ}$) on the surface of micro-patterns having the groove width and clearance of $50{\mu}m$.