• 전자공학회논문지
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• 제52권3호
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• pp.105-115
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• 2015

반도체 식각 전산모사에서는 플라즈마 입자를 생성하는 소스의 모델링이 필요하다. 본 논문에서는 플라즈마 식각 공정에서 사용하는 소스를 확률분포함수로 모델링하고, 몬테칼를로 방법을 이용하여 특정 프로프일의 플럭스를 계산하는 실험을 하였다. 소스의 모델링 파라미터로 소스와 셀 사이의 거리, 소스에서 방사하는 입자수가 있고, 플럭스 계산에 미치는 추가적인 파라미터로 프로파일 상의 셀의 수(셀의 면적)이 있다. 방사하는 입자 분포는 사용하는 소스의 물성에 따라 가우시안 분포와 코사인 분포로 모델링 할 수 있는데, 본 논문은 이들 각각에 대하여 파라미터를 바꿔가며 전산모사를 한 결과를 보인다. 오차율은 가우지안(Incident Flux)과 코사인분포(Incident Neutral Flux)에서 모두 입자 수의 증가에 따라 상당부분 감소하였으나 처리시간은 이보다 더 증가하였다. 셀수와 거리의 증가는 오차율을 약간 증가시켰고 처리시간도 증가시켰다. 본 논문의 실험 결과를 통해 처리 시간을 고려하여 적합한 플럭스의 계산을 유추할 수 있다.

• Restorative Dentistry and Endodontics
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• 제40권4호
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• pp.299-305
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• 2015

Objectives: The purpose of this study was to investigate the effectiveness of multiple decontamination procedures for salivary contamination after curing of a universal adhesive on dentin bond strength according to its etch modes. Materials and Methods: Forty-two extracted bovine incisors were trimmed by exposing the labial dentin surfaces and embedded in cylindrical molds. A universal adhesive (All-Bond Universal, Bisco) was used. The teeth were randomly divided into groups according to etch mode and decontamination procedure. The adhesive was applied according to the manufacturer's instructions for a given etch mode. With the exception of the control groups, the cured adhesive was contaminated with saliva for 20 sec. In the self-etch group, the teeth were divided into three groups: control, decontamination with rinsing and drying, and decontamination with rinsing, drying, and adhesive. In the etch-and-rinse group, the teeth were divided into four groups: control, decontamination with rinsing and drying, decontamination with rinsing, drying, and adhesive, and decontamination with rinsing, drying, re-etching, and reapplication of adhesive. A composite resin (Filtek Z350XT, 3M ESPE) was used for filling and was cured on the treated surfaces. Shear bond strength was measured, and failure modes were evaluated. The data were subjected to one-way analysis of variation and Tukey's HSD test. Results: The etch-and-rinse subgroup that was decontaminated by rinse, drying, re-etching, and reapplication of adhesive showed a significantly higher bond strength. Conclusions: When salivary contamination occurs after curing of the universal adhesive, additional etching improves the bond strength to dentin.

• 대한소아치과학회지
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• 제44권3호
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• pp.358-364
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• 2017

소아치과 영역에서 수복 치료에 널리 쓰이는 레진 치료의 술식 민감성 및 시간 감소에 대한 꾸준한 노력으로 새로운 접착제의 개발이 이루어지고 있는데 최근 출시된 접착제와 기존에 널리 쓰이는 두 단계 접착제와 비교 분석하여 임상적으로 적용하기에 어떠할지 평가해 보고자 하였다. 본 연구에서는 78개의 건전한 소구치를 3군으로 나누어 순면 법랑질에 새로 개발된 $Tetric^{(R)}$ N-Bond Universal (Ivoclar Vivadent, Liechtenstein)과 $GC^{(R)}$ G-Premio BOND (GC Co., Japan)를 실험군으로 하고 기존의 5세대 $3M^{TM}$ Single Bond2 (3M ESPE, USA)를 대조군으로 설정하여 동일하게 $Filtek^{TM}$ Z-350 (3M ESPE, USA)복합 레진을 접착시킨 후 접착제에 따른 전단접착강도를 비교 평가하였다. 그 결과 산부식 과정을 따로 적용하지 않은 두 실험군에서 각각의 전단접착강도가 산부식 과정을 포함한 대조군의 결과보다 통계학적으로 유의성 있게 낮은 결과를 나타내었다. 또한 새로 개발된 두 접착제간 비교에서는 $Tetric^{(R)}$ N-Bond Universal 제품이 $GC^{(R)}$ G-Premio BOND 제품보다 전단 접착 강도가 유의성 있게 큰 것으로 나타나 임상에서 제품을 선택할 때 참조할 수 있을 것으로 생각된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.50.1-50.1
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• 2009

Transparent conductive oxides (TCOs) play an important role in thin-film solar cells in terms of low cost and performance improvement. Al-doped ZnO (AZO) is a very promising material for thin-film solar cellfabrication because of the wide availability of its constituent raw materials and its low cost. In this study, AZO films were prepared by low pressurechemical vapor deposition (LPCVD) using trimethylaluminum (TMA), diethylzinc(DEZ), and water vapor. In order to improve the absorbance of light, atypical surface texturing method is wet etching of front electrode using chemical solution. Alternatively, LPCVD can create a rough surface during deposition. This "self-texturing" is a very useful technique, which can eliminate additional chemical texturing process. The introduction of a TMA doping source has a strong influence on resistivity and the diffusion of light in a wide wavelength range.The haze factor of AZO up to a value of 43 % at 600 nm was achieved without an additional surface texturing process by simple TMA doping. The use of AZO TCO resulted in energy conversion efficiencies of 7.7 % when it was applied to thep-i-n a-Si:H thin film solar cell, which was comparable to commercially available fluorine doped tin oxide ($SnO_2$:F).

• 한국전기전자재료학회논문지
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• 제13권7호
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• pp.551-556
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• 2000

We have investigated the effect of surface In composition with Si cell temperature on the In$_{0.1}$/Ga$_{0.9}$/As epilayers grown on GaAs substrates. The epilayers were grown by molecular beam epitaxy(MBE) method and were characterized by the pthotoreflectance(PR) measurements. The E$_{o}$ bandgap energies of In$_{0.1}$/Ga$_{0.9}$/As epilayers were observed at around 1.28 eV at room temperature, and the additional shoulder peaks appeared at the higher energies than E$_{o}$ with increase of Si doping concentrations. The intensity of the additional shoulder peak was decreased with lowering the measurement temperature and the peak disappeared with the increase of surface etching time. This results hows that In composition at surface of InGaAs epilayer is decreased with the increase of the doping cell temperature. We consider that the reason of the decrease of In composition at the surface should be due to In re-evaporation from the surface by radiation heat of Si doping cell.ell.ell.ell.

• Restorative Dentistry and Endodontics
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• 제30권6호
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• pp.493-504
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• 2005

본 연구는 상아질 접착제와 레진 시멘트의 적합성 여부를 알아보고자 시행하였다. 발거한 제3대구치의 상아질 표면을 노출시킨 후 Tescera ATL 복합레진 시편을 상아질 접착제 [All Bond 2 (Bisco), Clearfil SE Bond (Kuraray), Adper Prompt L-POP (3M), One-Up Bond F (Tokuyama)]와 레진시멘트 [Choice (Bisco), Panavia F (Kuraray), RelyX ARC (3M), Bistite II DC (Tokuyama)]로 접착하고 미세인장 결합강도 및 주사전자 현미경 관찰을 시행한 결론은 다음과 같다. 1. Clearfil SE Bond와 All-Bond 2가 Prompt L-Pop과 One-Up Bond F 보다 높은 미세인장 결합강도를 보였다(p<0.05). 2. Clearfil SE Bond와 All-Bond 2 사용시 1-step 상아질 접착제보다 혼성층이 두껍고 레진 tag가 길었다.

• 마이크로전자및패키징학회지
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• 제30권4호
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• pp.98-104
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• 2023

대기 중 구리-구리 플립칩(flip-chip) 접합을 위해 제안된 효율적 공정의 실현 가능성을 평가하고자 구리(Cu) 필라(pillar) 상 다공성 구리층의 형성 및 액상 환원제 투입 후 열압착 접합을 실시하였다. 구리 필라 상 다공성 구리층은 아연(Zn) 도금-합금화 열처리-선택적 아연 에칭(etching)의 3단계 공정으로 제조되었는데, 형성된 다공성 구리층의 두께는 평균 약 2.3 ㎛였다. 본 플립칩 접합은 형성 다공성 구리층에 환원성 용제를 침투시킨 후, 반건조 과정을 거쳐 열압착 소결접합으로 진행하였다. 용제로 인한 구리 산화막의 환원 거동과 함께 추가 산화가 최대한 억제되면서 열압착 동안 다공성 구리층은 약 1.1 ㎛의 두께로 치밀해지며 결국 구리-구리 플립칩 접합이 완수되었다. 그 결과 10 MPa의 가압력 하에서 대기 중 300 ℃에서 5분간 접합 시 약 11.2 MPa의 접합부 전단강도를 확보할 수 있었는데, 이는 약 50% 이하의 필라들만이 접합된 결과로서, 공정 최적화를 통해 모든 필라들의 접합을 유도할 경우 20 MPa 이상의 강도값을 쉽게 얻을 수 있을 것으로 분석되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1305-1308
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• 2003

A new technique is presented to construct a predictive model of plasma etch process. This was accomplished by combining a backpropagation neural network (BPNN) and a genetic algorithm (GA). The predictive model constructed in this way is referred to as a GA-BPNN. The GA played a role of controlling training factors simultaneously. The training factors to be optimized are the hidden neuron, training tolerance, initial weight magnitude, and two gradients of bipolar sigmoid and linear functions. Each etch response was optimized separately. The proposed scheme was evaluated with a set of experimental plasma etch data. The etch process was characterized by a $2^3$ full factorial experiment. The etch responses modeled are aluminum (A1) etch rate, silica profile angle, A1 selectivity, and dc bias. Additional test data were prepared to evaluate model appropriateness. The GA-BPNN was compared to a conventional BPNN. Compared to the BPNN, the GA-BPNN demonstrated an improvement of more than 20% for all etch responses. The improvement was significant in the case of A1 etch rate.

• Journal of the Optical Society of Korea
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• 제20권2호
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• pp.291-299
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• 2016

We have investigated the ultimate limits of nonuniform grating couplers (NGCs) for optimized fiber coupling to silicon waveguides, compared to uniform grating couplers (UGCs). Simple grating coupler schemes, which can be fabricated in etching steps of the conventional complementary metal-oxide semiconductor (CMOS) process on silicon-on-insulator (SOI) wafers without forming any additional overlay structure, have been simulated numerically and demonstrated experimentally. Optimum values of the grating period, fill factor, and groove number for ultimate coupling efficiency of the NGCs are determined from finite-difference time-domain (FDTD) simulation, and confirmed with experimentally demonstrated devices by comparison to those for the UGCs. Our simulated results indicate that maximum coupling efficiency of NGCs is possible when the minimum pattern size is below 50 nm, but the experimental value for the maximum coupling efficiency is limited by the attainable fabrication tolerance in a practical device process.

• 전자공학회논문지D
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• 제35D권2호
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• pp.60-69
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• 1998

Polysilicon surface mdoification tecnique is developed to reduce the sticking of microstructures fabricated by micromachining. Modified anti-sticking grain holes are simply formed by two-step dry eth without additional photolithography nor deposition of thin films. Both process-induced sticking and in-use sticking are successfully reduced more than two times by adopting grain holed polysilicon substrate. A sticking model for cantilever beam is derived. This model includes bending moment stems from stress gradient along the thickness directionof structural polysilicon. Because the surface tension of rinse liquid and the surface energy of the solids to be stuk tend to decrease in recently developed anti-sticking techniques, the effect of stress gradient will play an important role to analyze the sticking phenomena. Effect of the temperature during post-release rinse and dry is modelled and verified experimentally. Based on developed anti-sticking polysilicon structure and the sticking model, sticking of microstructure, fabricated by simple wet process including sacrificial layer etch and rinse with deionized water without special equimpment for post-release rinse and dry was alleviated more than 3.5 times.