• Journal of the Semiconductor & Display Technology
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• v.13 no.3
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• pp.61-67
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• 2014

Micro-cracks in crystalline silicon wafer often result in wafer breakage in solar wafer manufacturing, and also their existence may lead to electrical failure in post fabrication inspection. Therefore, the reliable detection of micro-cracks is of importance in the photovoltaic industry. In this paper, an experimental method to select optimal parameters in anisotropic diffusion filter is proposed. It can reliably detect micro-cracks by the distinct extension of boundary as well as noise reduction in near-infrared image patterns of micro-cracks. Its performance is verified by experiments of several type cracks machined.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.112-115
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• 2017

ITO thin films were grown on the glass substrate under various oxygen gas flow and substrate temperature by using FTS (Facing Target Sputtering) system. To investigate properties of as-prepared films for transparent electrical devices, we employed four-point probe, UV-VIS spectrometer, X-ray diffractometer (XRD), scanning electron microscopy (SEM), Hall Effect measurement system and Atomic Force Microscope (AFM). As a results, all of prepared samples has high transmittance of over 80 % in the visible range (300-800 nm). Their resistivity increased as a function of oxygen gas flow and substrate temperature due to their crystal structure and oxygen defect in the films. As-prepared films have a resistivity of under $10^{-4}({\Omega}-cm)$.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.113-118
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• 2011

This paper proposes computer visual inspection algorithms for PCB defects which are found in a manufacturing process. The proposed method can detect open circuit and short circuit on bare PCB without using any reference images. It performs adaptive threshold processing for the ROI (Region of Interest) of a target image, median filtering to remove noises, and then analyzes connected components of the binary image. In this paper, the connected components of circuit pattern are defined as 6 types. The proposed method classifies the connected components of the target image into 6 types, and determines an unclassified component as a defect of the circuit. The analysis of the original target image detects open circuits, while the analysis of the complement image finds short circuits. The machine vision inspection system is implemented using C language in an embedded Linux system for a high-speed real-time image processing. Experiment results show that the proposed algorithms are quite successful.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.60-65
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• 2019

In this paper, the hybrid illumination system for effectively detecting surface defects in steel plate with lowcontrast, non-uniformity and featureless is designed based on illuminance uniformity. First of all, characteristics of steel plate defects were considered and typical inspection illumination system is implemented. Optimum illumination parameters for uniformly illuminating an inspection area in the typical illumination system are selected based on the illuminance uniformity and illuminance distribution measurement. The illuminance uniformity and illuminance distribution are measured using an illuminometer based on the arduino. Through illuminance distribution analysis of the typical illumination, an hybrid illumination is designed by fusing bi-directional illumination and coaxial illumination. The hybrid illumination showed higher uniformity ratio and illuminance distribution than the typical illuminations. The hybrid illumination system showed the ability to uniformly illuminate the entire inspection region of steel plate surface.

• Journal of the Semiconductor & Display Technology
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• v.11 no.3
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• pp.1-6
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• 2012

In this paper, inspection system based on optical scanning mechanism is designed and developed for solar cell wafer. It consists of optical scanning mechanism, NIR camera optics, machinery and control system, algorithm of defect detection and software. Optical scanning mechanism is composed of geometrical camera optics and structured hybrid illumination system. It is used to inspection of surface defects. NIR camera optics is used for inspection of defects inside solar cell wafer. It is shown that surface and internal micro defects can be detected in developed inspection system for solar cell wafer.

• Journal of the Semiconductor & Display Technology
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• v.12 no.3
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• pp.29-34
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• 2013

Solar cell has been considered as renewable green energy. Its silicon wafer thickness is thinner due to manufacturing cost and accordingly micro cracks is often generated in the process. Micro cracks result in bad quality of solar cell, and so their accurate and reliable detection is required. In this paper, near-infrared optics system is newly designed based on the analysis of near-infrared transmittance characteristics and its important parameters are optimally selected using the design of experiment for micro crack detection in solar cell wafer. The performance of the proposed method is verified using several experiments.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.147-150
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• 2005

We process a novel approach cal led combined nanoimprint and photolithography (CNP) to greatly simplify the fabrication in conventional nanoimprint lithography (NIL). In this study, a novel HMM with anti-sticking $SiO_2$ layer is introduced to improve the quality of transferred pattern. The surface property was investigated using contact angle measurement and spectrophotometer. Replicate pattern with CNP using HMM showed complete pattern transfer without defect.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.26-31
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• 2018

In this paper, surface defects and typical illumination mechanisms for steel plates are analyzed, and then optimum illumination mechanism is selected using discrete wavelet transform (DWT) synthetic images and discriminant measure (DM). The DWT synthetic images are generated using component images decomposed by Haar wavelet transform filter. The best synthetic image according to surface defects is determined using signal to noise ratio (SNR). The optimum illumination mechanism is selected by applying discriminant measure (DM) to the best synthetic images. The DM is applied using the tenengrad-euclidian function. The DM is evaluated as the degree of contrast using the defect boundary information. The performance of the optimum illumination mechanism is verified by quantitative data and intuitive image looks.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.39-43
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• 2022

In this paper, a study was conducted on encapsulation technology for high mechanical stability of flexible displays. First, unlike conventional encapsulation barrier that exclude cracks as much as possible for low water vapor transmission rate (WVTR), mechanical properties were improved by using a defect suppression mechanism introduced with crack arresters. The zero-stress encapsulation barrier optimizes the residual stress of the thin film based to improve the internal mechanical stability. The zero-stress encapsulation barrier was applied to the organic light emitting diodes (OLEDs) to confirm its characteristics and lifetime. Due to improved internal mechanical stability, it has a longer lifetime more than 35% compared to conventional encapsulation technologies. As the zero-stress encapsulation barrier proposed in this study does not require additional deposition process, it is not difficult to apply it. Based on various advantages, it is expected to play an important role in flexible displays.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.2
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• pp.164-169
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• 2008

The effects of the antisite related defects on the electronic structure of silica and the gate leakage current have been investigated using first-principles calculations. Energy levels related to the antisite defects in silicon dioxide have been introduced into the bandgap, which are nearly 2.0 eV from the top of the valence band. Combining with the electronic structures calculated from first-principles simulations, tunneling currents through the silica layer with antisite defects have been calculated. The tunneling current calculations show that the hole tunneling currents assisted by the antisite defects will be dominant at low oxide field whereas the electron direct tunneling current will be dominant at high oxide field. With increased thickness of the defect layer, the threshold point where the hole tunneling current assisted by antisite defects in silica is equal to the electron direct tunneling current extends to higher oxide field.