• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.37.2-37.2
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• 2011

반도체공정에서 Photo-lithography는 특정 광원을 사용하여 구현하고자 하는 패턴을 기판상에 형성하는 기술이다. 이러한 Photo-lithography 공정에서는 패턴이 형성되어 있는 마스크가 핵심적인 역할을 하며 반도체소자의 전체적인 성능을 결정한다. 이에 따라 Photo-lithography용 마스크에 사용되는 Blank 마스크는 Defect의 최소화 및 우수한 평탄도 등의 조건들이 요구되고 있다. 이러한 Blank 마스크 재료로 광원을 효율적으로 투과시키는 성질이 우수하고 다른 재료에 비해 열팽창계수가 작은 석영기판이 사용되고 있다. 석영 기반의 마스크는 UV Lithography에서 주로 사용되고 있으며 그 밖에 UV-NIL (Nano Imrpint Lithography), EUVL (Extreme Ultra Violet Lithography) 등에도 이용되고 있다. 석영기판을 가공하여 Blank 마스크로 제작하기 위해 석영기판의 Lapping/Polishing 등이 핵심기술이며 현재 일본에서 전량 수입에 의존하고 있어, 이에 대한 연구의 필요성이 절실한 상황이다. 본 연구에서는 Blank 마스크제작을 위한 석영기판의 Polishing 공정에 사용되는 Ceria Slurry의 특성 연구 및 이에 따른 연마평가를 실시하였으며 첨가제의 조건에 따른 pH/Viscosity/Stability 등의 물리적인 특성을 관찰하여 석영기판 Polishing에 효율적인 Ceria slurry의 최적조건을 도출했다. 또한, 조건에 따른 Slurry의 정확한 분석을 위해 Zeta Potential Analyzer를 이용하여 연마입자의 크기 및 Zeta Potential에 대한 평가를 실시한 후 연마제와 석영기판의 Interaction force를 측정하였다. 상기 실험에 의해 얻어진 최적화된 연마 공정 조건하에서 Ceria slurry를 사용하여 연마평가를 실시함으로써 Removal Rate/Roughness 등의 결과를 관찰하였다. 본 연구를 통해 반도체 photo mask 제작을 위한 Ceria slurry의 주요특성을 파악하고 석영기판의 Polishing에 효율적인 조건을 도출함으로써 Lithography 마스크를 효율적으로 제작할 수 있을 것으로 예상된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1267-1268
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• 2013

• Journal of the Speleological Society of Korea
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• no.77
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• pp.21-30
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• 2007

Photo-lithography lies in the middle of the wafer fabrication process. It is often considered as the most critical step in the IC process. We use a mask in exposure steps of the photo-lithography. Typically, 20 to 25 different levels of masks are required to complete an IC device. That means, if a photo process can be developed with the use of only one photo mask, we can reduce more process cost. To satisfy this, we plan to develop an alternative photo mask. For this reason, we chose to use a LCD. We expect to develop a LCD panel that can be changed by electrical control. This is the main idea about the adjustive photo mask. The Photo mask made of LCD panel will replace the former one.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.682-688
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• 2009

A periodic away of zinc oxide(ZnO) micro-rods as fabricated by using chemical bath deposition and photo-lithography. Vertically aligned ZnO micro-rods array was successfully grown by chemical bath deposition method on ZnO seed layer. The ZnO seed layer was deposited on glass and the patterning was made by standard photo-lithography technique. The selective growth of ZnO micro-rods as achieved with the masked ZnO seed layer. The fabricated ZnO micro rods were found to be single crystalline and have grown along hexagonal c-axis direction of (0002) which is same as the preferred growth orientation of ZnO seed layer.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.12-18
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• 2020

In semiconductor manufacturing, defect detection is critical to maintain high yield. Currently, computer vision systems used in semiconductor photo lithography still have adopt to digital image processing algorithm, which often occur inspection faults due to sensitivity to external environment. Thus, we intend to handle this problem by means of using Mask R-CNN instead of digital image processing algorithm. Additionally, Mask R-CNN can be trained with image dataset pre-processed by means of the specific designed digital image filter to extract the enhanced feature map of Convolutional Neural Network (CNN). Our approach converged advantage of digital image processing and instance segmentation with deep learning yields more efficient semiconductor photo lithography inspection system than conventional system.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.295-299
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• 2012

Defect generation during organic bottom anti-reflective coating (BARC) in the photo lithography process is closely related to humidity control in the BARC coating unit. Defects are related to the water component due to the humidity and act as a blocking material for the etching process, resulting in an extreme pattern bridging in the subsequent BARC etching process of the poly etch step. In this paper, the lower limit for the humidity that should be stringently controlled for to prevent defect generation during BARC coating is proposed. Various images of defects are inspected using various inspection tools utilizing optical and electron beams. The mechanism for defect generation only in the specific BARC coating step is analyzed and explained. The BARC defect-induced gate pattern bridging mechanism in the lithography process is also well explained in this paper.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.303-303
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• 2007

Photo-imageable thick-film lithography technology was developed for the fabrication of embedded passives such as inductors and capacitors. In this study, photo-imageable dielectric and conductor pastes have apoted a negative type. Sodalime glass wafer, alumina substrate and zero-shrinkage LTCC green tapes were used as substrates. In result, The lithographic patterns were designed as lines and spaces for conductor material, or via-holes for ceramic, LTCC, materials. The scattering and reflection of UV-beam on the substrate had negative effects on fine patterning. The patterning performance was varied with the exposing and developing process conditions, and also varied with the substrate materials. Fine resolution of less then $50/50{\mu}m$ in line and space was obtained, which is difficult in screen printing method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.109-109
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• 2006

Screen printing (SP) metal contact is typically applied to the solar cells for mass production. However, SP metal contact has low aspect ratio, low accuracy, hard control of the substrate penetration and unclean process. On the other hand, photo lithograpy (PL) metal contact can reduce defects by metal contact. In this investigation, PL metal contact was obtained the multi-layer structure of Ti/Pd/Ag by e-beam process. We applied SP metal contact and PL metal contact to single crystalline silicon solar cells, and demonstrated the difference of conversion efficiency. Because PL metal contact silicon solar cell has Jsc (short circuit current density) better than silicon solar cell applied SP metal contact.

• Korean Journal of Optics and Photonics
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• v.20 no.1
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• pp.23-28
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• 2009

In this study, we propose an image stitching method for large-area holographic photo lithography. In this method, a hologram medium become a hologram mask for lithography. And the mask has information for stitched images. These images are recorded by signal images which are controlled with DMD (digital micro-mirror device), and serial hologram recording is achieved with a motorized linear stage. Using this method, fringe seams appear on the stitching area. To remove these fringe seams, double exposure holographic lithography is tried. Each stitched image is recorded and reconstructed with a different reference beam. The experiments confirm that fringe seams are removed.

• Korean Journal of Optics and Photonics
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• v.20 no.6
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• pp.334-338
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• 2009

Recently, with increasing demand for flat-panel display product, methods for large area patterning are required. TIR (total internal reflection) holographic photo-lithography isstudied as one of the methods of large area lithography. In conventional TIR holography, light sources for hologram recording and image reconstruction are coherent beams such as laser beams. If the image is reconstructed with an incoherent light source such a UV lamp, the image noise from the coherence of light will be reduced and the UV lamp will be a better light source for large area exposure. We analyzed the effect of spectral bandwidth and angular bandwidth of the light source in image reconstruction and verified image blurring with experiments. For large area patterning which has micro-scale line width, it is expected that TIR holographic photo lithography by UV lamp will become a low-noise and low-priced technique.