• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.345-352
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• 1997

Recently, in designing optical mask such as 4GDRAM, the scattering effect of electromagnetic wave must be considered. For this reason we claculated directly the mask function using the finite difference time domain(FDTD) method. The modification of image theory with this new mask function could explain clearly the scattering effect at the etched side wall of the submicron optical mask. The characteristics of the various type of alternating PSM were investigated. According to the simulation, the dual wet etch process was the most useful fabrication technique to overcoe the light scattering off at the shifted opening.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.152-156
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• 2004

A new tool of surface patterning technique for general purpose lithography was developed based on shadow mask method. This paper describes the fabrication of a new type of miniaturized shadow mask. The shadow mask is fabricated by photolithography and etching of 100-mm full wafer. The fabricated shadow mask has over 388 membranes with apertures of micrometer length scale ranging from 1${\mu}{\textrm}{m}$ to 100s ${\mu}{\textrm}{m}$ made on each 2mm${\times}$2mm large low stress silicon nitride membrane. It allows micro scale patterns to be directly deposited on substrate surface through apertures of the membrane. This shadow mask method has much wider choice of deposit materials, and can be applied to wider class of surfaces including chemical functional layer, MEMS/NEMS surfaces, and biosensors.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.15-20
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• 1997

This paper presents the experimental study of the non-contact temperature measurement for the shadow mask of cathode ray tube using InSb sensor. At present, High resolution of CRT(Cathode Ray Tube) is needed broadly; therefore, the measurement of temperature distribution of shadow mask in CRT during operation is important to analyze the thermal deformation of shadow mask. Most of the studies could not measure the temperature distribution of shadow mask precisely. We studied the temperature dis- tribution of shadow mask using InSb photo sensor for 17" cathode ray tube (CRT). Experiments using ther- mocouple are performed to validate the results of non-contact measurement. The results agree well with those results of non-contact method using InSb sensor.nsor.

• Journal of Korea Multimedia Society
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• v.23 no.1
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• pp.8-14
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• 2020

For a reliable fingerprinting system, improving fingerprint matching accuracy is crucial. In this paper, we try to improve a binary image fingerprint matching performance by utilizing auxiliary information, power mask, which is obtained while constructing fingerprint DB. The power mask is an expected robustness of each fingerprint bit. A caveat of the power mask is the increased storage cost of the fingerprint DB. This paper mitigates the problem by reducing the size of the power mask utilizing spatial correlation of an image. Experiments on a publicly-available image dataset confirmed that the power mask is effective in improving fingerprint matching accuracy.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1071-1074
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• 2007

6Mask CMOS process in low temperature polycrystalline silicon thin film transistors (poly-Si TFTs) has been developed and verified by manufacturing a 6Mask CMOS AMLCD panel. The novel 6Mask CMOS process is realized by eliminating the storage mask, gate mask and via open mask of conventional structure.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.164-168
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• 2007

Deformation of a shadow mask is one of the problems encountered during the deposition of organic materials for manufacturing large size OLED. The larger the glass substrate, the larger the shadow mask becomes. But as the size of the shadow mask increases, its deformation becomes more severe, thereby making it difficult to deposit organic materials in a precise pattern on a substrate. In this paper, a new type mask-frame structure is proposed. The proposed mask-frame structure making a curved mask has the ability of reducing drooping of mask. The test frame is fabricated and evaluation experiments are performed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.9
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• pp.731-737
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• 2002

Nonlinear vibration of the CRT shadow mask with impact damping wires is analyzed in consideration of the mask tension distribution and the effect of wire impact damping. A reduced order FEM model of the shadow mask is obtained from dynamic condensation of the mass and stiffness matrices, and damping wire is modeled using the lumped parameter method to effectively describe its contact interactions with the shadow mask. The nonlinear contact-impact model is composed of spring and damper elements, of which parameters are determined from the Hertzian contact theory and the restitution coefficient, respectively. The analysis model of the shadow mask with damping wires is experimentally verified through impact tests of shadow masks performed in a vacuum chamber.

• Journal of the Semiconductor & Display Technology
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• v.3 no.2
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• pp.5-9
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• 2004

Microcircuit fabrication requires precise control of impurities in tiny regions of the silicon. These regions must be interconnected to create components and VLSI circuits. The patterns to define such regions are created by lithographic processes. In order to image features smaller than 70 nm, it is necessary to employ non-optical technology (or next generation lithography: NGL). One such NGL is extreme ultra-violet lithography (EUVL). EUVL transmits the pattern on the wafer surface after reflecting ultra-violet through mask pattern. If particles exist on the blank mask, it can't transmit the accurate pattern on the wafer and decrease the reflectivity. It is important to care the blank mask. We removed the particles on the wafer using focused ion beam (FIB). During removal, FIB beam caused damage the multi layer mask and it decreased the reflectivity. The relationship between particle removal and reflectivity is examined: i) transmission electron microscope (TEM) observation after particle removal, ii) reflectivity simulation. It is found that the image mode of FIB is more effective for particle removal than spot and bar mode.

• Journal of Information Display
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• v.2 no.1
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• pp.34-37
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• 2001

We developed the tension mask of which thickness increased from 25 urn to 50 urn to reduce the mask cost and improve the vibration property. First of all, the limitation by which rail structure can support is calculated and the optimal thickness of mask is determined. To prevent the reduction of brightness and brightness uniformity, the dimensions of mask was reassigned. As a result, the increase of mask thickness brought about a reduction in cost and improvement of howling property which had been a weak point of flat CRTs.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.129-131
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• 2004

극자외선 리소그래피(EUV lithography) 기술은 50nm 이하의 선폭을 가지는 차세대 소자 제작에 있어서 선도적인 기술 중 하나이다. EUVL 에서 필수적인 요소중의 하나가 mirror 로 사용되는 blank mask 이다. Blank mask 에 있어서 가장 중요한 요소는 반사도이다. 이 blank mask 는 Si substrate 위에 반사를 위한 Mo/Si pair 가 40pair 이상 적층되어있다. Blank mask 는 매우 청결해야한다. 만약 결함이 있다면 blank mask 에는 치명적이다 결함은 blank mask 에 있어서 반사도를 떨어뜨리는 주 요소이기 때문이다. 그 결함에는 amplitude defect 과 phase defect 이 있다. FIB 에서는 amplitude defect 을 수정하는 것이 가능하다. 우리는 FIB 를 이용하여 mage mode, spot mode, bar rotation mode 를 사용하여 amplitude defect을 수정하였다. 그리고, 그 결과 효과적으로 amplitude defect을 수정하였다.