• 한국기계가공학회지
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• 제13권6호
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• pp.139-144
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• 2014

As a result of a mismatch of the residual stress between both sides of the silicon wafer, which warps and distorts during the patterning process. The accuracy of the warpage measurement is related to the calibration. A CCD camera was used for the calibration. Performing optimization of the error function constructed with phase values measured at each pixel on the CCD camera, the coordinates of each light source can be precisely determined. Measurement results after calibration was performed to determine the warpage of the silicon wafer demonstrate that the maximum discrepancy is $5.6{\mu}m$ with a standard deviation of $1.5{\mu}m$ in comparison with the test results obtained by using a Form TalySurf instrument.

• 대한산업공학회지
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• 제41권6호
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• pp.579-587
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• 2015

Semiconductor manufacturing industry is a high density integration industry because it generates a vest number of data that takes about 300~400 processes that is supervised by numerous production parameters. It is asked of engineers to understand the correlation between different stages of the manufacturing process which is crucial in reducing production costs. With complex manufacturing processes, and defect processing time being the main cause. In the past, it was possible to grasp the corelation among manufacturing process stages through the engineer's domain knowledge. However, It is impossible to understand the corelation among manufacturing processes nowadays due to high density integration in current semiconductor manufacturing. in this paper we propose a canonical correlation analysis (CCA) using both wafer test voltage variables and fail bit counts variables. using the method we suggested, we can increase the semiconductor yield which is the result of the package test.

• 한국소음진동공학회논문집
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• 제19권12호
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• pp.1347-1355
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• 2009

This paper demonstrates the validity of spectral element analysis for modeling the high-frequency dynamic behaviors of a beam with a surface-bonded piezoelectric wafer through a laboratory test. In the spectral element analysis, the high-frequency electro-mechanical interaction can be considered properly with relatively low computational cost compared to the finite element analysis. In the verification test, a cantilever beam with a surface-bonded piezoelectric wafer is forced to be in steady-state motion by exerting the harmonic driving voltage signal on the piezoelectric wafer. A laser scanning vibrometer is used to obtain the overall dynamic responses of the structure such as resonance frequencies, the associated mode shapes, and frequency response functions up to 20 kHz. Then, these dynamic responses from the test are compared to those computed by the spectral element analysis. A two-dimensional finite analysis is conducted to obtain the asymptotic solutions for the comparison purpose as well.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.90-98
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• 2004

Nano/micro-scale studies on friction properties were conducted on Si (100) and three self-assembled monolayers (SAMs) (PFOTC, DMDM, DPDM) coated on Si-wafer by chemical vapor deposition technique. Experiments were conducted at ambient temperature $(24{\pm}1^{\circ}C)$ and humidity $(45{\pm}5\%)$. Nano-friction was evaluated using Atomic Force Microscopy (AFM) in the range of 0-40nN normal loads. In both Si-wafer and SAMs, friction increased linearly as a function of applied normal load. Results showed that friction was affected by the inherent adhesion in Si-wafer, and in the case of SAMs the physical/chemical structures had a major influence. Coefficient of friction of these test samples was also evaluated at the micro-scale using a micro-tribotester. It was observed that SAMs had superior frictional property due to their low interfacial energies. In order to study of the effect of contact area on friction coefficient at the micro-scale, friction was measured for Si-wafer and DPDM against Soda Lime balls (Duke Scientific Corporation) of different radii 0.25 mm, 0.5 mm and 1 mm at different applied normal loads $(1500,\;3000\;and\;4800{\mu}N)$. Results showed that Si-wafer had higher friction coefficient than DPDM. Furthermore, unlike that in the case of DPDM, friction was severely influenced by wear in the case of Si-wafer. SEM evidences showed that solid-solid adhesion to be the wear mechanism in Si-wafer.

• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.738-747
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• 2006

The friction behaviour of Si-wafer, diamond-like carbon (DLC) and two self-assembled monolayers (SAMs) namely dimethyldichlorosilane (DMDC) and diphenyl-dichlorosilane (DPDC) coated on Si-wafer was studied under loading conditions in milli-newton (mN) range. Experiments were performed using a ball-on-flat type reciprocating micro-tribo tester. Glass balls with various radii 0.25 mm, 0.5 mm and 1 mm were used. The applied normal load was in the range of 1.5 mN to 4.8 mN. Results showed that the friction increased with the applied normal load in the case of all the test materials. It was also observed that friction was affected by the ball size. Friction increased with the increase in the ball size in the case of Si-wafer. The SAMs also showed a similar trend, but had lower values of friction than those of Si-wafer In-terestingly, for DLC it was observed that friction decreased with the increase in the ball size. This distinct difference in the behavior of friction in DLC was attributed to the difference in the operating mechanism. It was observed that Si-wafer and DLC exhibited wear, whereas wear was absent in the SAMs. Observations showed that solid-solid adhesion was dominant in Si-wafer, while plowing in DLC. The wear in these two materials significantly Influenced their friction. In the case of SAMs their friction behaviour was largely influenced by the nature of their molecular chains.

• 전자공학회논문지A
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• 제29A권11호
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• pp.62-69
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• 1992

In this paper, a measurement system of surface flatness test using 2-Bucket algorithm phase-shifting interferometry is designed and constructed. In the conventional surface flatness test system using phase shifting interferometry, it is needed more than 3 fringe datas but we propose 2-Bucket algorithm phase-shifting interferometry which only uses two fringe datas. 2-Bucket algorithm uses the relative phase differences of the neighbour pixels. If we watch the result of phase-shift error test simulation, 2-Bucket algorithm has the same calculating values that 3-Bucket, 4-Bucket and 5-Bucket algorithm have them. Experiments have been carried out on the silicon wafer. The measurement of silicon wafer's surface flatness shows that the flatness topography using 2-Bucket algorithm is similar to that of other algorithms.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1318-1319
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• 2011

In this paper, we analyzed of growth and electrical characteristics of micro-cracks with thermal effect in PV module. The micro-cracks are increasing the breakage risk over the whole value chine from the wafer to the finished module, because the wafer or cell is exposed to mechanical stress. we experimentally analyze the direct impact of micro-cracks on the module power and the consequences after artificial aging. The first step, we made micro-cracks in PV module by mechanical load test according to IEC 61215. Next, PV modules applied the thermal cycling test, because microcracks accelerated aging by thermal cycling test. according to IEC61215. Before every test, we checked output and EL image of PV module.

• 마이크로전자및패키징학회지
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• 제7권2호
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• pp.55-62
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• 2000

Si-wafer에 단면 코팅된 UBM(Under Bump Metallurgy)의 젖음성을 Sn-Pb 솔더에서 평가하기 위하여 wetting balance 법을 사용하였다. 단면 코팅된 UBM의 젖음곡선은 양면 코팅된 시편의 젖음 곡선과 비교할 때, 젖음곡선의 모양이 비슷하고 젖음곡선을 특징짓는 변수들의 온도에 대한 변화경향이 일치하였다. 단면 코팅된 금속층의 젖음성을 젖음곡선으로부터 정의한 새로운 젖음 지수 $F_{min}$, $F_{s}t_{s}$로 평가할 수 있었다. Au/Cu/Cr UBM은 젖음시간의 측면에서 Au/Ni/Ti UBM보다 젖음성이 우수하였다 Si-wafer에 단면 코팅된 UBM과 Sn-Pb 솔더의 접촉각을 $F_{s}$와 기울어짐각을 측정하고 메니스커스의 정적상태에서 힘의 평형으로부터 유도된 식을 이용하여 계산할 수 있었다.

• 마이크로전자및패키징학회지
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• 제10권4호
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• pp.53-60
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• 2003

CCD(Charge-Coupled Device) wafer와 같이 표면이 polymer 성분의 micro lens로 구성되어있는 경우 passivation 막을 도포하지 않는 것이 보통인데, 이때 particle이 lens 표면에 쉽게 달라붙는 현상이 나타나게 된다. 특히 sawing 하면서 발생하는 particle은 치명적인 불량을 유발한다. 본 연구에서는 sawing에서 발생한 particle을 효과적으로 flushing하기위한 방안으로 측면노즐과 중심노즐의 분사위치, 분사각도, 퍼짐각도를 최적화 하고, 아울러 flushing 노즐을 추가한 새로운 형태의 wafer saw를 도입하였다. 개선된 saw를 적용하여 실험한 결과 particle로 인한 CCD chip의 불량률이 9.l%로부터 0.63%로 현격하게 개선되었음을 확인할 수 있었다.

• 한국기계가공학회지
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• 제11권2호
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• pp.144-151
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• 2012

Polishing is not only one of the most frequently adopted processes in modern industries, but also the most critical one to the surface quality of the products such as semi conductor wafers and LED sapphire wafers. With the required specifications for the wafer surface quality getting more and more strengthened, the manufacturers are spending huge amount of cost to renew the machine to meet the enhanced surface specifications. Surface qualities of the wafers are mostly damaged by the structural vibrations of the polishing machines. In this paper, the dynamic characteristics of a wafer polishing machine have been analyzed through the frequency response test and the computer simulation. And the supporting structure of a polishing machine has been investigated to minimize the vibration transmissions, to improve the stability of the machine and further to reduce the defects of the polished products. The result of the study shows that simple design modifications of the supporting structure without altering the main structure of the machine can substantially suppress the vibrations of the machine with negligible expenses.