• 통합자연과학논문집
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• 제2권3호
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• pp.207-210
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• 2009

Multiple rugate structures can be etched on a silicon wafer and placed in the same physical location, showing that many sharp spectral lines can be obtained in the optical reflectivity spectrum. Porous silicon samples were prepared by electrochemical etch of heavily doped p-type silicon wafers. The etching solution consisted of a 3:1 volume mixture of aqueous 48% hydrofluoric acid and absolute ethanol. Galvanostatic etch was carried out in a Teflon cell by using a two-electrode configuration with a Pt mesh counterelectrode. A sinusoidal current density waveform varying between 51.5 and $74.6mA/cm^2$ is applied. The anodization current was supplied by a Keithley 2420 high-precision constant current source which is controlled by a computer to allow the formation of PSi multilayer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2509-2511
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• 1998

In this study, we formed the piezoelectric film and estimated its characteristics for sensor application. The $Pb(Zr,Ti)O_3(PZT)$ was chosen as piezoelectric material and we used Sol-Gel method to form film. To increase film thickness, the multiple coatings were performed, and the good characteristics obtained in thick film compared to thin film. Because PZT film showed fine etching property as well as other good characteristics, it was thought that it was appropriate material for sensor fabrication.

• 센서학회지
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• 제14권5호
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• pp.357-361
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• 2005

Low-stress silicon nitride (LSN) thin films with embedded metal line have been developed as free standing structures to keep microspheres in proper locations and localized heat source for application to a chip-based sensor array for the simultaneous and near-real-time detection of multiple analytes in solution. The LSN film has been utilized as a structural material as well as a hard mask layer for wet anisotropic etching of silicon. The LSN was deposited by LPCVD (Low Pressure Chemical Vapor Deposition) process by varing the ratio of source gas flows. The residual stress of the LSN film was measured by laser curvature method. The residual stress of the LSN film is 6 times lower than that of the stoichiometric silicon nitride film. The test results showed that not only the LSN film but also the stack of LSN layers with embedded metal line could stand without notable deflection.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.976-979
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• 2002

A focusing grating coupler (FGC) was not fabricated by the 'Continuous Path Control' writing strategy but by an electron-beam lithography system of more general exposure mode, which matches not only the address grid with the grating period but also an integer multiple of the address grid resolution (5 nm), To more simplify the fabrication, we are able to reduce a process step without large decrease of pattern quality by excluding a conducting material or layer such as metal (Al, Cr, Au), which are deposited on top or bottom of an e-beam resist to prevent charge build-up during e-beam exposure. A grating pitch period and an aperture feature size of the FGC designed and fabricated by e-beam lithography and reactive ion etching were ranged over 384.3 nm to 448.2 nm, and $0.5{\times}0.5mm^2$ area, respectively, This fabrication method presented will reduce processing time and improve the grating quality by means of a consideration of the address grid resolpution, grating direction, pitch size and shapes when exposing. Here our investigations concentrate on the design and efficient fabrication results of the FGC for coupling from slab waveguide to a spot in free space.

• 대한치과보철학회지
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• 제44권4호
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• pp.383-393
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• 2006

Statement of problem : Limited research on flowable resin has been undertaken on its application directly on dentin associated with the adhesive systems. Purpose : This study was to evaluate the shear bond strengh and fracture aspect of flowable resin on human dentin with various types of dentin bonding adhesives with thermo cycling effect. Materials and methods: Filtek-Flow(3M ESPE, USA) was used as flowable resin and Eighty human molars were randomly divided into 4 groups : three dentin bonding adhesives (Scotchbond-Multipurpose : 3-step contentional system, One-Step : One-bottle system. Prompt L-Pop : All-in-one, self-etching primer) and 32% etching treatment without bonding adhesive as a control group. For evaluating their durability of bonding, each group was subdivided : storaging in the water at 37$^{\circ}C$(24 hours) and thermocycling (0$^{\circ}C$-55$^{\circ}C$, 30 seconds intervals, 1000 cycle). Shear bond strength tests were performed and resin-dentin interface and fracture mode were observed. Results were analysed by one-way ANOVA and Scheffe's multiple range test. Results and Conclusion : 1. At 0 cycle, the mean shear bond strength of One-Step exhibited the highest value of all groups(p<0.05), and there were no significant differences between Prompt L-Pop and Scotchbond-Multipurpose, Scotchbond-Multipurpose and control(p>0.05). After 1000 thermocycling, One-Step exhibited higher value than other groups(p<0.05), and there were no significant differences among other groups (p>0.05). 2. The shear bond strength of each group was significantly decreased after thermocycling except Scotchbond-Multipurpose (p>0.05). 3. The most common failure mode was adhesive type and mixed type, next in order.

• 한국정보통신학회논문지
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• 제3권3호
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• pp.661-669
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• 1999

프로브 카드는 IC(integrated circuit) 칩을 테스트할 때, 테스트 시스템의 가장 중요한 부분의 하나이다. 본 연구는 다수의 반도체 칩을 동시에 테스트 할 수 있는 범프(bump)형 수직형 프로브 카드에 관한 것이다. 프로브는 범프 팁을 가지는 실리콘 캔틸레버로 구성되어 있다. 캔틸레버의 최적 크기를 결정하기 위하여 캔틸레버의 크기는 유한요소해석에 의하여 결정되었다. 프로브는 SDB웨이퍼를 사용하여 RIE, 등방성 에칭, 그리고 벌크 마이크로머시닝에 의하여 제조되었다. FEM에 의해 결정된 최적 크기로 제작된 프로브 카드는 범프의 높이가 30$\mum$, 캔틸레버의 두께가 $\mum$, 빔의 폭이 100 $\mum$, 길이가 400 $\mum$, 이었다. 제조된 프로브 카드의 접촉 테스트에서 측정된 접촉 저항은 $2 \Omega$ 미만이고, 2만회의 접촉동안 접촉 저항의 변화가 거의 없는 특성을 보였다. 따라서 20,000회 이상의 수명을 가질 수 있음을 알 수 있었다.

• Transactions on Electrical and Electronic Materials
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• 제3권1호
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• pp.30-37
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• 2002

A focusing grating coupler (FGC) was not fabricated by the 'Continuous Path Control'writing strategy but by an electron-beam lithography system of more general exposure mode, which matches not only the address grid with the grating period but also an integer multiple of the address grid resolution (5 nm). To more simplify the fabrication, we are able to reduce a process step without large decrease of pattern quality by excluding a conducting material or layer such as metal (Al, Cr, Au), which are deposited on top or bottom of an e-beam resist to prevent charge build-up during e-beam exposure. A grating pitch period and an aperture feature size of the FGC designed and fabricated by e-beam lithography and reactive ion etching were ranged over 384.3 nm to 448.2 nm, and 0.5 $\times$ 0.5 mm$^2$area, respectively. This fabrication method presented will reduce processing time and improve the grating quality by means of a consideration of the address grid resolution, grating direction, pitch size and shapes when exposing. Here our investigations concentrate on the design and efficient fabrication results of the FGC for coupling from slab waveguide to a spot in free space.

• 전기전자학회논문지
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• 제23권3호
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• pp.1077-1081
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• 2019

태양전지의 표면으로 입사되는 빛은 태양전지의 내부로 모두 흡수되지 못하고 그 일부가 기판 표면에서 반사되어 손실이 발생한다. 때문에 기판 표면의 반사손실을 줄이거나 태양전지 내부의 생성 전하를 증기시키기 위한 연구가 많이 진행 중이다. 본 논문에서는 유리 기판의 표면을 습식 에칭하여 표면을 거칠게 형성하는 표면 처리를 진행하였으며, 거칠어진 표면의 구조적 특성을 분석하였다. 그리고 빛이 입사되는 유리 기판의 각도를 변화하면서 그에 따른 분광특성 또한 분석하였다. 입사되는 빛이 에칭된 표면으로 조사될 때 다중반사에 의해서 유리 기판 내부에 빛을 재흡수할 확률이 증가함을 확인하였다. 또 유리 기판의 각도를 변화하면서 빛을 입사할 때 빛의 투과 및 반사 성능은 변화하지 않음을 확인하였다.

• 인터넷정보학회논문지
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• 제6권1호
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• pp.105-114
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• 2005

본 논문에서는 다중 시계열 패턴을 분석하여 계측 값을 예측하는 방법에 관하여 기술한다. 본 논문의 목적은 표본패턴들 중에서 입력패턴과 가장 유사한 패턴을 찾은 다음 그 표본패턴이 가지는 실측값과의 오차율을 산출하는 것이다. 따라서 인식이 아니라 계측이며 하드웨어가 아닌 소프트웨어 기술을 제안하다. 본 논문에서 제안하는 방법은 초기화, 인식 및 계측 등의 단계로 구성된다. 초기화 단계에서는 중요도를 사용하여 인자들 각각의 가중치를 산출한다. 학습 단계에서는 수집된 표본패턴을 먼저 DTW와 LBG 알고리즘을 사용하여 각 인자별 독립적으로 군집화를 수행한 다음, 모든 표본패턴에 대하여 군집의 번호들로 구성된 코드열을 생성한다. 계측 단계에서는 입력패턴에 대한 코드열을 생성한 다음 해슁으로 표본패턴들 중에서 같은 코드열을 가지는 표본들을 찾고, 이 표본들 중에서 입력패턴에 가장 잘 정합되는 하나의 표본을 선택하다. 최종적으로 이 패턴이 가지고 있는 실측값과 오차율을 출력한다. 성능평가는 반도체생산장치 중에서 하나인 식각장치로부터 얻어진 자료에 적용하여 수행한다.

• 산업공학
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• 제22권2호
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• pp.126-134
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• 2009

As product quality and yield are essential factors in semiconductor manufacturing, monitoring the main manufacturing steps is a critical task. For the purpose, FDC(Fault detection and classification) is used for diagnosing fault states in the processes by monitoring data stream collected by equipment sensors. This paper proposes an FDC model based on decision tree which provides if-then classification rules for causal analysis of the processing results. Unlike previous decision tree approaches, we reflect the structural aspect of the data stream to FDC. For this, we segment the data stream into multiple subregions, define structural features for each subregion, and select the features which have high relevance to results of the process and low redundancy to other features. As the result, we can construct simple, but highly accurate FDC model. Experiments using the data stream collected from etching process show that the proposed method is able to classify normal/abnormal states with high accuracy.