• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.35-38
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• 2008

A pattern master and a Ni stamper for 50nm class of patterns are fabricated through e-beam lithography and Ni electroforming process. A model pattern set is designed, which is based on unit patterns of 50nm, 100nm, 150nm and 200nm in length and 50nm in width. The e-beam process is optimized to fabricate designed patterns with some parameters including dose, accelerating voltage, focal distance and developing time. For Ni electroforming to fabricate Ni stamper, a seed layer, a conducting layer, is deposited first on the pattern master fabricated by an e-beam lithography process. Ni, Ti/Ni and Cr are first tested to find optimal seed layer process. Currently the best result is obtained when adopting Cr deposited to be 100nm thick with continuous tilting motion of the master substrate during the deposition process.

• Electrical & Electronic Materials
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• v.10 no.4
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• pp.349-354
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• 1997

This paper aims at studying the improvement of test method for t-weight sensitive fault (t-wsf) detect. The development of RAM fabrication technology results in not only the increase at device density on chips but also the decrease in line widths in VLSI. But, the chip size that was large and complex is shortened and simplified while the cost of chips remains at the present level, in many cases, even lowering. First of all, The testing patterns for RAM fault detect, which is apt to be complicated , need to be simplified. This new testing method made use of Local Lower Bound (L.L.B) which has the memory with the beginning pattern of 0(l) and the finishing pattern of 0(1). The proposed testing patterns can detect all of RAM faults which contain stuck-at faults, coupling faults. The number of operation is 6N at 1-weight sensitive fault, 9,5N at 2-weight sensitive fault, 7N at 3-weight sensitive fault, and 3N at 4-weight sensitive fault. This test techniques can reduce the number of test pattern in memory cells, saving much more time in test, This testing patterns can detect all static weight sensitive faults and pattern sensitive faults in RAM.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.4
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• pp.7-12
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• 2014

A transparent poly methyl methacrylate (PMMA) optical micro-pyramid array-pattern is designed and fabricated using an injection modeling technique. The device's optical characteristics are tested and analyzed theoretically. In the optical pattern generated using the fabricated PMMA pattern, the components, due to not only refraction but also diffraction, are observed simultaneously. Wave optic modeling and analysis reveals that the energy ratio between the diffraction and refraction in the optical pattern are dependent on the critical dimension of the optical pattern such that the refraction and diffraction tend to be directly and inversely proportional to the pattern dimension, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.178-184
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• 2006

Hot embossing is to fabricate desired pattern on the polymer substrate by pressing the patterned mold against the substrate which is heated above the glass transition temperature, and it is a high throughput fabrication method for bio chip, optical microstructure, etc. due to the simultaneous large area patterning. However, the bad pattern fidelity in large area patterning is one of the obstacles to applying the hot embossing technology for mass production. In the present study, PDMS pad was used as a cushion on the backside of the micro-patterned 4 inch Si mold to improve the pattern fidelity over the 4 inch PMMA sheet by increasing the conformal contact between the Si mold and the PMMA sheet. The pattern replicability improvement over 4 inch wafer scale was evaluated by comparing the replicated pattern height and depth for PDMS-cushioned Si mold against the rigid Si mold without PDMS cushion.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.213-216
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• 2007

LGP (light guide plate) of LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of the major components which affects the product quality of LCD. In the present study, the optical patterns of LGP(2.2") are manufactured by three different methods, namely, laser ablation, chemical etching and LiGA - reflow, respectively. The pattern surface images and roughness of mold and product were compared to check the optical characteristics. From the results of measurement the optical patterns fabricated by LiGA - reflow method showed the best geometric structure as intended in design and the lowest roughness among those.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.759-762
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• 2005

The LGP(Light Guide Panel) for the back light unit that is used to the 2.2" TFT LCD was designed and fabricated. The method of the pattern design which is the most important in the design of the LGP was converted the V-cutting method into the Dot method. This newly developed Dot method provided a good uniformity in the brightness at the LGP, which was a very difficult problem to solove in the V-cutting method. The experiment result of the newly designed LGP shows the brightness uniformity 90% and the brightness 3656 $cd/\;m^2$ which is 20% higher than the commercial products.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1489-1492
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• 2005

Compared to other nano-patterning techniques, Nano imprint Lithography (NIL) has some advantages of high throughput and low process cost. To imprint low temperature and pressure, UV Nano imprint Lithography, which using the monomer based UV curable resin is suggested. Because fabrication of high fidelity pattern on topographical substrate is difficult, bi-layer Nano imprint lithography, which are consist of easily removable under-layer and imprinted pattern, is being used. If residual layer is not remained after imprinting, and under-layer is removed by oxygen RIE etching, we might be able to fabricate the bi-layer pattern for easy lift-off process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.14-17
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• 2000

The rise throughput and the stability in fabrication of device can be obtained by applying of CMP process to STI structure in 0.18um semiconductor device. To employ in STI CMP, the reverse moat process has been added thus the process became complex and the defects were seriously increased. Removal rates of each thin films in STi CMP was not equal hence the devices must to be effected, that is, the damage was occured in the device dimension in the case of excessive CMP process and the nitride film was remained on the device dimension in the case of insufficient CMP process than these defects affect the device characteristics. We studied the current sensing method in STI-CMP with the reverse moat pattern.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.2
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• pp.23-27
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• 2001

Microarray-based DNA chips provide an architecture for multi-analyte sensing. In this paper, we report a new approach for DNA chip microarray fabrication. Multifunctional DNA chip microarrays were made by immobilizing many kinds if DNAs on transducers (particles). DNA chip microarrays were prepared by randomly distributing a mixture of the particles on a chip pattern containing thousands of micro meter-scale sites. The particles occupied different sites from array to array. Each particle cam be distinguished by a tag that is established on the particle. The particles were arranged on the chip pattern by the random fluidic self-assembly (RFSA) method, using hydrophobic interaction.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.4
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• pp.332-335
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• 2008

PMMA light guiding plate with nano pattern was fabricated by nano imprint lithography method. A silicon mold for electroplating of nickel was fabricated by conventional photolithography process. A nickel stamp for nano imprint lithography was fabricated by electroplating process using silicon mold. The nano imprint lithography was performed on PMMA plate at $140^{\circ}C$ under pressure of 20kN. The nano pattern on PMMA plate was investigated using FE-SEM. It is shown that the patterns were well transferred for several steps and the nano imprint lithography method could be applied for fabricating patterns of light guiding plate.