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In this article the recent progress in the elements of EUV lithography is presented. Source power around 205W was demonstrated and further scaling up is going on, which is expected to be implemented in the field within 2017. Source availability keeps improving especially due to the introduction of new droplet generator but collector lifetime needs to be verified at each power level. Mask blank defect satisfied the HVM goal. Resist meets the requirements of development purposes and dose needs to be reduced further to satisfy the productivity demand. Pellicle, where both the high transmittance and long lifetime are demanded, needs improvements especially in pellicle membrane. Potential issues in high-NA EUV are discussed including resist, small DOF, stitching, mask infrastructure, whose solutions need to be prepared timely in addition to high-NA exposure tool to enable this technology.

As an emergency encountered in orthopedic practice requiring prompt diagnosis and aggressive treatment, necrotizing fasciitis around the hip must be discriminated from Fournier gangrene. The current case report describes a patient who suffered from bilateral type I necrotizing fasciitis around the hips, which was alleviated by prompt surgical debridement and intensive postoperative care.

산업의 고도화 및 새로운 기계의 도입, 화학물질 사용 등 산업재해의 다양한 양상과 더불어 생산설비들의 자동화, 대형화로 인해 산업재해 발생의 양상이 점차 다양해지고 있다. 국내 산업재해는 OECD(Organization for Economic Cooperation and Development) 경제협력개벌기구대비, 상대적 하위수준에 있어 기업 발생 산업재해는 근로자들의 심리적 및 치교와 보상 손실에도 타격이 되어 기업 총생산과 이윤 추구에도 중요문제가 야기되고 있다. 더불어, 장애자와 사망유족들의 증가로 생활 안정문제 등 사회적 문제도 제기된다. 이러한 동기에서 본 논문은 산업재해 통계와 산재예방 사업을 분석하고, 시스템다이내믹스 법론의 이용하여 산업재해율을 예측하고 평가하는 모델을 개발하였다. 모델은 근로자수 모델, 재해자수 모델, 재해율 모델 등 총 12개의 모델로 구성되었고, 규모별 분석에서는 근로자수를 기준으로 12개 그룹으로, 업종별 분석에서는 제조업, 건설업 등 총 10개의 업종으로 구분하여 개발하였다. 개발된 모델을 토대로 업종별 규모별 산업재해율을 예측하고 산재예방사업을 다각도로 평가하는 방법론을 제시하였다.

Abrupt changes in sidewall profile were induced in pulsed plasma etch process for high aspect ratio isolation trench structuring. Impacts of operational parameters when applying pulsed RF bias power were investigated. Silicon sidewall chipping problems were removed mainly by increasing bias power level and pulse frequency. The chemical sensitivity of O2 has shown decreased in extremely narrow trench spaces of high pattern density

APP based on the smart phone is being utilized to various scopes such as medical services in hospitals, financing services at banks and credit card companies, and ubiquitous technologies in companies and homes etc. In this service environment, exposures of smart phones cause loss of assets including leaks of official/private information by outsiders. Though secret keys, pattern recognition technologies, and single image authentication techniques are being applied as protective methods, but they have problems in that accesses are possible by utilizing static key values or images like pictures. Therefore, this study proposes a face authentication technology for protecting smart phones from these dangerous factors and problems. The proposed technology authenticates users by extracting key frames of user`s facial images by real time, and also controls accesses to the smart phone. Authentication information is composed of multiple key frames, and the user` access is controlled by distinction algorism of similarity utilizing DC values of image`s pixel and luminance.

To address the scalability of phase change memory (PCM), we study a 1-D thickness scaling effect on threshold switching voltage (Vth), Vth drift, high resistance state (RESET) resistance (RRESET) drift, and crystallization temperature (Tcrys). We use a pseudo three-terminal device to accurately correlate the amorphous region thickness to the observed characteristics. The pseudo 3-terminal device is a fully functional PCM cell and enables 1-D thickness scaling study down to 6 nm without the need for ultrafine lithography. Vth scales down to 0.65-0.5 V (at 25°C-75°C) for 6-nm-thick Ge2Sb2Te5 (GST), showing that stable read operation is possible in scaled PCM devices. The Vth drift measurement suggests that Vth drift can be attributed to threshold switching field (Eth) drift, whereas Vth0, i.e., Vth at zero thickness, stays almost constant. RRESET drift shows no dependence on the amorphous GST thickness. Tcrys is ~175°C for the device with 6-nm-thick GST, compared with ~145°C of thick GST. From the 1-D scaling study, no significant hurdles against scaling are found down to 6 nm. Further study of scaling effect on endurance and development of scalable selection device is needed to assess the ultimate scalability of PCM.

We studied the misalignment between active and gate layer in terms of silicon dislocation caused by high temperature anneal process in SOG based STI gap-fill process. The SOG process is one of good candidates to overcome gap-fill limitation due to its excellent gap-fill characteristics. However, the SOG process needs high temperature anneal process to convert from Si-H, N-H to Si-O bond, which leads to the misalignment due to large stress change. We suggest that silicon defect is generated from ion bombardment at trench etch process and accelerated from hysteresis at anneal process. The O2 cure process is known as one of feasible methods to cure silicon damage through recrystallization. Based on this model, the misalignment was significantly improved as removing the defect through O2 cure process following trench etch process.

High-k dielectrics like Ta2O5, TiO2 etc. should overcome high leakage current due to the low energy band-gap property for applying to the future DRAM device below 50nm design rule beyond. Various techniques including metal doping and bi-layer scheme were studied to improve the leakage current of I-V characteristics. The leakage current of Dy or Zr doped TiO2 could be improved depending on the doping concentration. Nb doping in Ta2O5 could increase the dielectric constant within the appropriate level of leakage current at the operation voltage. Bi-layer scheme of high-k dielectrics like HfO2-TiO2 or ZrO2-TiO2 also applied to reduce the leakage current with the high work function Ru electrode. Combination of high work function Ru as a top electrode with the bottom TiN electrode could reduce the leakage current by increasing band offset at the interface between the high-k and the electrode.

This paper analyses the risk probability of an underwater tunnel excavation using an earth pressure balance (EPB) type tunnel boring machine (TBM). An event tree analysis (ETA) has been applied to quantify the risk at the preliminary design stage of the tunnel. Probable results, which may be sequenced from specific initiating events, are analyzed, and adequate general countermeasures (safety functions) are selected to ensure safety against risks. To identify the initiating events, various data on underwater tunneling such as empirical analyses; design reports; case studies of practical problems; numerical analyses and model test results; and hydrological analysis results were used. Event trees corresponding to three significant initiating events were constructed. Each event tree consists of five countermeasures that construct 32 paths, and the probability of each path is calculated. A quantitative risk assessment was performed and the occurrence probabilities and criticalities of the paths depending on the initiating events were considered. Based on these ETA results, it was found that the selected underwater tunnel site still has a considerable probability of accidents in spite of common countermeasures. Based on the evaluated risks, improved target probabilities are proposed to reduce the probability of disaster during construction. Additional countermeasures, in other words mitigation actions, corresponding to the new target are considered. As a result, technical risks and economical losses of property can be minimized in a systematic way. It was found that the ETA is an effective method for the evaluation and quantitative analysis of probable risks and for the proposition of countermeasures for hazardous environmental conditions such as the underwater tunnel.

When a tunnel is excavated underneath a groundwater table, groundwater flows into the tunnel and consequently, seepage forces act on the cross-section of the tunnel. Such seepage forces significantly affect the ground reaction curve, which is defined by the relationship between the internal pressure and displacement of the tunnel wall. From a practical point of view, a simplified analytical solution of the ground reaction curve accounting for the seepage forces with steady-state flow was developed in this study based on ground reaction curve theories from earlier studies. The simplified analytical solution derived in this study was validated by numerical analysis. The changes in the ground reaction curve according to various ground and groundwater table conditions were investigated. Finally, the simplified analytical solution of the ground reaction curve developed in this study can be used for approximate design of circular openings such as tunnels excavated underneath a groundwater table with seepage forces.

Tunneling in difficult geological conditions is often inevitable especially in urban areas. Ground improvement and reinforcement techniques are required to guarantee safe tunnel excavations and/or to prevent damage to adjacent structures. The steel pipe-reinforced multi-step grouting method has been recently applied to tunnel sites as an auxiliary technique in Korea for impermeabilization in underwater tunnels as well as for reinforcement. However, this technique has been usually employed empirically without much understanding with regard to its effect on the tunnel safety. In this study, the face stability with steel pipe-reinforced multi-step grouting in underwater tunnels was evaluated by simultaneously considering two factors: one is the effective stress acting on the tunnel face calculated by limit theorem and limit equilibrium method; the other is the seepage force obtained by means of numerical analysis. This study revealed that the influence of the steel pipe-reinforced multi-step grouting on the support pressure required for the stability of the tunnel face in dry condition is not significant while there is relatively a significant reduction in seepage forces by adopting the technique in the underwater tunnel. The effect of permeability anisotropy on the seepage force acting on the tunnel face was also assessed by conducting a coupled analysis.

Recent years, as a rapid development of multimedia technology, video database system to retrieve video data efficiently seems to core technology in the oriented society. This thesis describes an efficient automatic frame detection and location method for content based retrieval of video. Frame extraction part is consist of incoming / outgoing car frame extraction and car number frame extraction stage. We gain star/end time of car video also car number frames. Frames are selected at fixed time interval from video and key frames are selected by color scale histogram and edge operation method. Car frame recognized can be searched by content based retrieval method.

In this study, two factors are simultaneously considered for assessing tunnel face stability. The first is the effective stress acting on the tunnel face calculated by upper bound solution, and the other is the seepage force calculated by numerical analysis under the condition of steady-state groundwater flow. The seepage forces calculated by numerical analysis are compared with the results of a model test. The upper bound solution taking into consideration the seepage force acting on the tunnel face, shows that the minimum support pressure for the face stability is equal to the sum of the effective support pressure that is obtained from the upper bound solution based on effective stress and the seepage pressure acting on the tunnel face. It was found that the average seepage pressure acting on the tunnel face is proportional to the hydrostatic pressure at the same elevation, and the magnitude is about 22% of the hydrostatic pressure for the drainage type tunnel and about 28% for the waterproof type tunnel. The seepage forces obtained from the results of a model test showed similar trends as those calculated by numerical analysis.Key words: face stability, upper bound solution, seepage force, model test.

In this letter, a cost-effective vertical diode scheme for next-generation memory devices, including phase-change memories (PCMs), is realized. After the contact formation for diodes with only one mask layer, an amorphous silicon (a-Si) film was deposited within the contacts using SiH4 ramp-up ambient in a conventional batch-type furnace in order to minimize the growth of native oxide. A deposition/etch-back/deposition scheme enabled us to achieve robust vertical diodes without any seams or interfacial oxide layer within the vertical diode pillars. Subsequent annealing at 600 °C provided solid-phase epitaxial alignment of the a-Si layer. An ideality factor revealed that the new scheme provided noticeable crystallinity of the silicon diodes. Moreover, the electrical characteristics of the diodes verified that the scheme was suitable for full operation of PCM devices.

We first present chemical-vapor-deposited GeBiTe (CVD GBT) in a confined cell for high-performance phase-change random access memory (PRAM). Due to the fast crystallization of GBT, we were able to reduce the speed to less than 26 ns while maintaining endurance characteristics up to 109 cycles. Our results indicate that the scalable PRAM device enabling the use of PRAM in dynamic RAM and storage class memory applications can be realized using CVD GBT.

Needs for the performance improvement of memory subsystem in big data and clouding computing era begin to open new markets for emerging memories such as phase change memory, spin-torque-transfer magnetic memory, and metal oxide memory. To fulfill these needs, a cost-effective and high-speed phase change memory cell scheme was introduced at 19nm technology node, which is directly scalable down to 1y or 1z nm nodes and can be extendable to stacked array for higher density. Here, key technologies such as self-aligned cell patterning and vertical poly-Si diode switch on metal word line were adopted. In addition, damascene Ge-Sb-Te technologies were optimized to improve programming speed and to show excellent cell performances.

In this paper, the seepage force problems arising from the flow of groundwater into a tunnel were studied. Firstly, the effect of seepage forces acting on the tunnel lining was studied for the case of shallow drainage-type tunnels and these results were compared with the lining stresses developed for waterproof-type tunnels. This model was then reviewed through a comparison with an actual case study of the Seoul Subway Line No. 5. Secondly, the effect of seepage forces on the tunnel face stability was studied. In this study, two factors were considered simultaneously. The first factor considered was the effective stresses acting on the tunnel face, calculated from the upper bound solution of limit analysis and the other factor was the seepage forces, calculated from a numerical analysis under a steady-state of groundwater flow conditions. Consequently, reasonable design concepts applicable to the design of tunnel lining and to the evaluation of the support pressure required for maintaining the stability of the tunnel face were suggested for underwater tunnels.

In this paper, current-voltage-temperature (I-V-T) characteristics of vertical diodes realized by different selective epitaxial growth techniques have been investigated. Diodes by the batch-type cyclic SEG process at low temperature have shown eligible performances for vertical switches, including ideality factor of 1.08, off-current of 1.0×10−12 A and on/off-ratio of 2.4×108. The optimization of crystallographic defects and series resistance is expected to be the most critical for the performances of vertical diodes for next generation memories.

Flowable CVD (Chemical Vapor Deposition) process having merits in terms of both superior gap-fill performance of SOD (Spin-on Dielectric) and process stability of CVD was introduced for the interlayer dielectric (ILD) in sub-20nm devices based on new concept and precursor. Remote plasma during low temperature deposition and ozone treatment was adopted to stabilize the film. We also developed a novel Flowable CVD process which does not oxidize Si or electrode, resulted in removal of Si 3 N 4 stopper layer as an oxidation or diffusion barrier. After the application of Flowable CVD to 20nm DRAM ILD, we could reduce not only loading capacitance of Bit-line by 15% but also enhance comparable productivity. Through the successful development of sub-20nm DRAM ILD Gap-fill process, Flowable CVD was successful demonstrated as a promising candidate for mass production-worthy ILD in sub-20nm next generation devices.

Data retention characteristic is one of the most critical issues in low power DRAMs because it determines idle currents of self-refresh operation. Compared to normal healthy cells, a few ppm orders of cells in a tail distribution have much higher leakage currents. The origin of the leaky cells (so called weak cells or tail cells) has been quite arguable for the past decades [1, 2], but it should be scrutinized in order to achieve long data retention time. In this paper, we have thoroughly investigated the behavior of the retention weak cells using a newly generated combination program and TEM analysis so as to discover and explain their origins

To improve the IPD reliability of NAND flash memory, plasma oxidation was introduced as the post-treatment process of ONO (Oxide/Nitride/Oxide) IPD. The LP-CVD SiO2 modified by plasma oxidation showed the excellent electrical properties. e.g., low leakage current, high breakdown voltage etc. By the analysis of Tof-SIMS and XRR, we could observe the several changes of physical characteristics such as the reduction of impurities (H, N etc.), the increase of oxide density, and the improvement of oxide surface roughness. We found out the appropriate treatment condition to be able to densify oxide layer without the addition of ONO Equivalent Oxide Thickness (EOT). The LP-CVD SiO2 prepared by plasma oxidation was used for the ONO IPD of 50nm NAND flash device and also compared with the conventional LP-CVD SiO2 in the aspect of the IPD reliability.

Gout is characterized by recurrent attacks of arthralgia, and deposition of monosodium urate crystals in and around the joints of the extremities and soft tissues. Monosodium urate crystals are observed most frequently at the 1st metatarsophalangeal joint and usually presented in the ankle and wrist joint. However, no case of an intratendinous tophus in the patellar tendon has been reported in Korean literature. In this report, we found monosodium urate crystals in the patellar tendon on magnetic resonance imaging images and intratendinous tophus were visible to the naked eye by excision. We reported on the case of a patient who experienced an unusual intratendinous tophus in the patellar tendon.

We studied factors which affect cell Vth variation in the floating gate flash memory. By simulation and experiment, we showed that the shape of STI (shallow trench isolation) and the tunnel oxide thickness in the STI edge were the main control factors. For example, sharp and thin oxide in the STI edge caused an uncontrolled F-N gate current in the program or erase operation, which directly indicated the amount of threshold voltage in the flash memory. Furthermore, we found that tunnel oxide thinning was closely related to the activation energy in the oxidation process. Smaller activation energy resulted in better thinning and better cell Vth distribution.

This report was designed to investigate a rare case that brachialis tear and hematoma caused by acute elbow posterior dislocation. We studied a 20-year-old male patient with right elbow joint pain after outstretched injury. Physical examination showed instability of hright elbow joint and simple radiography indicated a posterolateral dislocation of right elbow joint. Computed tomography taken after closed reduction using Parvin technique revealed a few small bone fragment located on posterior humerus capitulum. Magnetic resonance imaging showed complete tear of brachialis and anterior articular capsule with hematoma. The patient was managed with long arm splint and hinge brace for an elbow dislocation with brachialis rupture and hematoma. The elbow joint range of motion was recovered to be in a normal range, and pain was diminished. There are few reported cases of acute elbow posterior dislocation combined with brachialis rupture and hematoma. The patient showed good clinical outcome after conservative treatment.

Objectives: To analyze the influence of fracture patterns and the result of bone mineral density on cement leakage after percutaneous vertebroplasty for osteoporotic vertebral compression fractures. Summary of Literature Review: Leakage of bone cement after vertebroplasty has known to be related with the direction of cortical disruption of fractured vertebral body and low bone mineral density (BMD). Materials and Methods: One hundred eighty-two patients with osteoporotic vertebral compressions were studied from January 2009 to August 2013. The patients’ fracture levels and patterns were compared. Among them, the cement leakage patterns were analyzed in 105 patients who had undergone vertebroplasty. The findings were compared with fracture patterns including cortical disruption and BMD. Results: Seventy-five cases of cement leakage were observed. Among them, intradiscal leakage was the most common type of leakage. In the patient group with low BMD, there was a high incidence of lower and posterior cortical disruption in the fractures. Patients with posterior cortical disruption demonstrated a higher incidence of leakage into the spinal canal and anterior cortex. No significant correlation was observed between fracture patterns and leakage. Conclusions: A surgeon should use caution in performing vertebroplasty in patients with low BMD and posterior disruption of the vertebral cortex.

Study Design: A case report. Objectives: To investigate the outcomes of recapping laminoplasty for the treatment of atraumatic spinal interdural hematoma. Summary of Literature Review: There are several causes for a spinal hematoma. The occurrence of spinal hematoma is rare; in particular, the ones arising atraumaticaly are considered extremely rare. Materials and Methods: We studied a 33 year old male patient without any known risk factor. Magnetic resonance image has revealed an intraspinal epidural cyst compressing on the spinal nerve. After performing recapping laminoplasty, followed by partial excision of dura mater and resection of hematoma, we were able to observe another layer of dura mater, confirming the location of hematoma within two epidural layers, i.e., an interdural hematoma. Results: Performing recapping laminoplasty is a more effective and less invasive procedure for removing cyst than conventionally used laminectomy. Patients were found to have synostosis after three months post-op, and they have exhibited neither lumbosacral pain nor lower limb motor weakness after six months follow-up. There were no recurrences or complications reported on our study. Conclusion: There are a few reported cases of atraumatic spinal interdural hematoma. Our study shows that performing pars osteotomy with recapping laminoplasty yield good clinical outcome for the treatment of atraumatic spinal interdural hematoma.