• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.523-523
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• 2012

As the wafer geometric requirements continuously complicated and minutes in tens of nanometers, the expectation of real-time add-on sensors for in-situ plasma process monitoring is rapidly increasing. Various industry applications, utilizing plasma impedance monitor (PIM) and optical emission spectroscopy (OES), on etch end point detection, etch chemistry investigation, health monitoring, fault detection and classification, and advanced process control are good examples. However, process monitoring in semiconductor manufacturing industry requires non-invasiveness. The hypothesis behind the optical monitoring of plasma induced ion current is for the monitoring of plasma induced charging damage in non-invasive optical way. In plasma dielectric via etching, the bombardment of reactive ions on exposed conductor patterns may induce electrical current. Induced electrical charge can further flow down to device level, and accumulated charges in the consecutive plasma processes during back-end metallization can create plasma induced charging damage to shift the threshold voltage of device. As a preliminary research for the hypothesis, we performed two phases experiment to measure the plasma induced current in etch environmental condition. We fabricated electrical test circuits to convert induced current to flickering frequency of LED output, and the flickering frequency was measured by high speed optical plasma monitoring system (OPMS) in 10 kHz. Current-frequency calibration was done in offline by applying stepwise current increase while LED flickering was measured. Once the performance of the test circuits was evaluated, a metal pad for collecting ion bombardment during plasma etch condition was placed inside etch chamber, and the LED output frequency was measured in real-time. It was successful to acquire high speed optical emission data acquisition in 10 kHz. Offline measurement with the test circuitry was satisfactory, and we are continuously investigating the potential of real-time in-situ plasma induce current measurement via OPMS.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.388-395
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• 2015

The waste gate valve (WGV) for gasoline vehicles operate in a harsh high-temperature environment. Hence, WGVs are typically made of Inconel 713C, which is a type of Ni-based superalloy. Recently, the metal injection molding (MIM) process has attracted considerable attention for parts used under high-temperature conditions. In this study, an MIM analysis for the head and other parts of the WGV is conducted using a commercial CAE program Moldflow. Further, optimal manufacturing conditions are determined by analyzing flow characteristics at various injection times and locations. Moreover, to improve the accuracy of the analysis results, we compare the actual temperature of the mold during injection processing with that observed through the analysis. As the results, metal injection patterns of analysis are well in accord with these of short shot test. And the temperature variations of analysis is also very similar with those of feedstock when metal injection molding.

• Journal of the Korean Data and Information Science Society
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• v.26 no.2
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• pp.367-376
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• 2015

Today, big data has become a hot keyword in that big data may be defined as collection of data sets so huge and complex that it becomes difficult to process by traditional methods. Clustering method is to identify the information in a big database by assigning a set of objects into the clusters so that the objects in the same cluster are more similar to each other clusters. The similarity measures being used in the cluster analysis may be classified into various types depending on the nature of the data. In this paper, we computed upper and lower limits for probability interestingness measure based similarity measures without marginal probability such as Yule I and II, Michael, Digby, Baulieu, and Dispersion measure. And we compared these measures by real data and simulated experiment. By Warrens (2008), Coefficients with the same quantities in the numerator and denominator, that are bounded, and are close to each other in the ordering, are likely to be more similar. Thus, results on bounds provide means of classifying various measures. Also, knowing which coefficients are similar provides insight into the stability of a given algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2587-2593
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• 2014

Ceramic Injection Molding (CIM) is one of wide used processes in industry field and the applications are gradually being expanded to parts of medical and electric devices. In this study, the CIM process were analyzed with FEM and process parameters were studied and analyzed the effect on product quality. The shape of simple flat plate was compared to the shapes with the hole, with the round corner portion or with the side wall portion. If there are holes then the hole around the uneven density distribution and the defects such as weld lines could be occurred. The Large radius of the corners of the product give good formability and fluidity. Not only the shape parameters of product but also the process parameters during CIM are studied. The simulation results showed that the process parameters of temperature, initial fractions and velocity are important design parameters to improve the quality of products.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1017-1024
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• 2017

Carbon thin films were deposited by HiPIMS(High Power Impulse Magnetron Sputtering). The properties and microstructures of carbon thin film were investigated with power, pressure, bias voltage and duty cycle. As the HiPIMS power increased, the deposition thickness increased and the surface tended to be rough. The increase in pressure also tended to make the surface rough, but the deposition thickness was not proportional to the pressure. As the bias voltage increased, the surface roughness became worse, the deposition thickness increased and then decreased from the critical bias voltage. Changes in the duty cycle have caused problems such as arcing, which is affected by the chamber structure and the size of the target. The $sp^2/sp^3$ fractions of thin films were estimated by XPS and it was confirmed that the fraction of thin films made by HiPIMS were larger than the fraction of thin films made by DC sputtering.

• Korean Journal of Metals and Materials
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• v.48 no.7
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• pp.630-638
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• 2010

The present investigation has been performed on the mixing behavior and microstructural development during fabrication of Fe micro-nano powder feedstock for a micro-powder injection molding process. The mixing experiment using a screw type blender system was conducted to measure the variations of torque and temperature during mixing of Fe powder-binder feedstock with progressive powder loading for various nano-powder compositions up to 25%. It was found that the torque and the temperature required in the mixing of feedstock increased proportionally with increasing cumulative powder loading. Such an increment was larger in the feedstock containing higher content of nano-powder at the same powder loading condition. However, the maximum value was obtained at the nano-powder composition of not 25% but 10%. It was owing to the 'roller bearing effect' of agglomerate type nano-powder acting as lubricant during mixing, consequently leading to the rearrangement of micro-nano powder in the feedstock. It is concluded that the improvement of packing density by rearrangement of nano-powders into interstices of micro-powders is responsible for the maximum powder loading of about 71 vol.% in the nano-powder composition of 25%.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.291-298
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• 2023

SRAM-based in-memory computing is one of the technologies to solve the bottleneck of von Neumann architecture. In order to achieve SRAM-based in-memory computing, it is essential to design efficient SRAM bit-cell. In this paper, we propose a low-power differential sensing 8+T SRAM bit-cell which reduces power consumption and improves circuit performance. The proposed 8+T SRAM bit-cell is applied to ripple carry adder which performs SRAM read and bitwise operations simultaneously and executes each logic operation in parallel. Compared to the previous work, the designed 8+T SRAM-based ripple carry adder is reduced power consumption by 11.53%, but increased propagation delay time by 6.36%. Also, this adder is reduced power-delay-product (PDP) by 5.90% and increased energy-delay- product (EDP) by 0.08%. The proposed circuit was designed using TSMC 65nm CMOS process, and its feasibility was verified through SPECTRE simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.777-784
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• 2023

A sense amplifier is an essential peripheral circuit for designing a memory and is used to sense a small differential input signal and amplify it into digital signal. In this paper, a high-speed sense amplifier applicable to in-memory computing circuits is proposed. The proposed circuit reduces sense delay time through transistor Mtail that provides an additional discharge path and improves the circuit performance of the sense amplifier by applying m-GDI (: modified Gate Diffusion Input). Compared with previous structure, the sense delay time was reduced by 16.82%, the PDP(: Power Delay Product) by 17.23%, the EDP(: Energy Delay Product) by 31.1%. The proposed circuit was implemented using TSMC's 65nm CMOS process, while its feasibility was verified through SPECTRE simulation in this study.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.100-103
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• 2004

The culture condition and medium composition for the enhanced mycelial growth of Inonotus mikadoi IMSNU 32058 were investigated. The optimal temperature and pH for the mycelial growth were $27^{\circ}C$ and pH 4.5, respectively. Among the complex media tested, the malt extract medium and Phellinus igniarius medium were very good for mycelial growth of I. mikadoi. When Czapek-Dox medium was used as a minimal medium for cultivation of mycelia, xylose, raffinose and carboxymethyl cellulose were very excellent as a carbon and energy source. With respect to carbohydrate, sucrose and glucose were very good carbon sources. In general, organic complex nitrogen sources were better than other inorganic ones. As the organic complex nitrogen sources tested, yeast extract, soytone, proteose peptone and bacto peptone were the best as a source of organic nitrogen. When ammonium sulfate as an inorganic source of nitrogen was used, the enhanced mycelial growth was shown. p-Aminobenzoic acid was proved to be most appropriate source of vitamin. After the mycelia of I. mikadoi was cultivated at $27^{\circ}C$ for 5 days in MEM broth (pH 4.5), the activities of both exomycelial and endo-mycelial enzymes were determined. Among endomycelial enzymes assayed, the specific activity of laccase was much higher than those of other enzymes. When the fungus was grown in MEM broth, exomycelial specific enzyme activity of laccase was comparatively high. However, little or no enzyme activities of protease, chitinase and lipase were found.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.141-152
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• 2018

Although the 1997 Raw Data of the National Wealth Statistical Survey (South Korea) is timely 20-year-old data, it is meaningful as a benchmarking in the capital stock estimations of Korea, which is estimated by PIM (permanent inventory method). In the case of machinery/equipment, it is the data that can analyze in depth the changes in the industrial structure of Korea. In the case of ASL (average service life) which has economic concept, since the change of ASL is not so large, ASL yielded by the Raw Data of the 1997 National Wealth Statistical Survey is meaningful as reference value for the ASL estimated by the Bank of Korea and the National Statistical Office. As you know Japan has changed its service life due to changes in its industrial structure. However, many of its assets are still used for the years indicated in Showa (before 1989). The same trend with other countries such as Japan. However, the United States is constantly devoted to assessing the useful ASL and value of assets by distinguishing between the Hulten-Wykoff models and those not. Korea has also benchmarked the useful ASL of the United States and Japan when it conducted its own survey every 10 years by due diligence until 1997. In this study, the 'constraint' Iowa curve estimation by the Raw Data of the 1997 National Wealth Statistical Survey is based on the age records of the assets and the maximum age of the assets appropriately derived. And then we made modified Iowa curve by smoothing. From this modified one, we suggested ASL by asset. After 1997, the vintage disposal data directly were collected by the National Statistical Office with Oh Hyun Seung, Cho Jin Hyung, in order to estimate the useful ASL. Since then, the B/S team of the Economic and Statistics Bureau of the Bank of Korea has been working on a new concept of content training.