• Journal of the Microelectronics and Packaging Society
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• v.19 no.4
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• pp.51-56
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• 2012

In order to fabricate through-Si-vias for thermal vias by using wet etching process, anisotropic etching behavior of Si substrate was investigated as functions of concentration and temperature of TMAH solution in this study. The etching rate of 5 wt%, 10 wt%, and 25 wt% TMAH solutions, of which temperature was maintained at $80^{\circ}C$, was $0.76{\mu}m/min$, $0.75{\mu}m/min$, and $0.30{\mu}m/min$, respectively. With changing the temperature of 10 wt% TMAH solution to $20^{\circ}C$ and $50^{\circ}C$, the etching rate was reduced to $0.067{\mu}m/min$ and $0.233{\mu}m/min$, respectively. Through-Si-vias of $500{\mu}m$-depth could be fabricated by etching a Si substrate for 5 hours in 10 wt% TMAH solution at $80^{\circ}C$ after forming same via-pattern on each side of the Si substrate.

• International Journal of Control, Automation, and Systems
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• v.3 no.3
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• pp.469-476
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• 2005

Performance of a force-torque sensor is affected significantly by an error signal that is included in the sensor signal. The error sources may be classified mainly into two categories: one is a structural error due to inaccuracy of sensor body, and the other is a noise signal existing in sensed information. This paper presents a principle of 6-axis force-torque sensor briefly, a double-hole structure to be able to improve a structural error, and then a signal conditioning to reduce the effect of a noise signal. The validity of the proposed method is investigated through experimental study, which shows that SIN ratio is improved significantly in our experimental setup, and the sensor can be implemented cheaply with reasonable performance.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.47-55
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• 1995

Proximity-coupled open-end microstrip interconnections in bilevel planar structures are investigated through three-dimensional finite-difference time-domain(3D-FDTD) method. Three types of EMC (electromagnetically coupled) microstriplines are considered, collinear lines, transverse lines and modified EMC structure. From the analyzed results, it is found that these EMC interconnections have the coupling coefficient enough to interconnect lines in bilevel structures over a broad-band. The computed results of the modified EMC structure was compared with measurement from physical model and the computed results of via hole interconnection.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.40-44
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• 2010

opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. A dynamical sensing range as a important parameter introduced to maintain the our protocol performance. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.273-276
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• 2010

Opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.317-322
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• 2013

We have proposed and demonstrated a low numerical aperture technique to measure the depth of through silicon vias (TSVs) using white-light scanning interferometry. The high aspect ratio hole like TSV's was considered to be impossible to measure using conventional optical methods due to low visibility at the bottom of the hole. We assumed that the limitation of the measurement was caused by reflection attenuation in TSVs. A novel interference theory which takes the structural reflection attenuation into consideration was proposed and simulated. As a result, we figured out that the low visibility in the interference signal was caused by the unbalanced light intensity between the object and the reference mirror. Unbalanced light can be balanced using an aperture at the illumination optics. As a result of simulation and experiment, we figured out that the interference signal can be enhanced using the proposed technique. With the proposed optics, the depth of TSVs having an aspect ratio of 11.2 was measured in 5 seconds. The proposed method is expected to be an alternative method for 3-D inspection of TSVs.

• Journal of Electrochemical Science and Technology
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• v.10 no.3
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• pp.271-275
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• 2019

Anodic $TiO_2$ nanotubes were simultaneously grown and doped with $RuO_2$ by single-step anodization in a negatively-charged $RuO_4{^-}$ precursor. Subsequently, a high positive voltage was imposed on the nanotubes in an $F^-$-based electrolyte (a process referred to as potential shock), which led to the formation of a through-hole $RuO_2$-doped $TiO_2$ nanotube membrane without significant loss of the $RuO_2$ catalyst. XPS results confirmed that the doped Ru metal was converted into $RuO_2$ as the potential shock voltage increased. Further increases in the potential shock voltage led to the formation of $RuO_x/Ru$ in the $TiO_2$ nanotubes. All of our results clearly showed that a through-hole catalyst-doped $TiO_2$ nanotube membrane can be produced by a sequence consisting of single-step anodization and the potential shock process.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.4
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• pp.47-56
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• 2015

In this paper, the Thermal behavior and reliability characteristics of carbon CCL (Copper Claded Layer), which can be used as the core of HDI (High Density Interconnection) PCB (Printed Circuit Board) are evaluated through experiments and numerical analysis using CAE (Computer Aided Engineering) software. For the characterization of the carbon CCL, it is compared with the conventional FR-4 core and Heavy Cu core. From research results, the deformation amount of the flexure strength of PCB is the highest with pitch grade carbon and thermal behavior of PCB is lowest as temperature increases. In addition, TC (Thermal Cycling), LLTS (Liquid-to-Liquid Thermal Shock) and Humidity tests have been applied in the PCB with carbon core and the reliability of PCB with carbon core is confirmed through reliability tests. Also, possibility of uneven surface of the via hole and wear of the drill bit due to the carbon fibers are analyzed. surface of the via hole is uniform, the surface of the drill bit is smooth. Therefore, it is proved that the carbon CCL has the drilling workability of the same level as conventional core material.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.75-75
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• 2010

3D 패키징 기술은 전기소자의 소형화, 고용량화, 저전력화, 높은 신뢰성등의 요구와 함께 그 중요성이 대두대고 있다. 이러한 3D 패키징의 연결방법은 와이어 본딩 또는 플립칩등의 기존의 방법에서 TSV(Through Silicon Via)를 이용하여 적층하는 방법이 주목받고 있다. TSV는 기존의 와이어 본딩과 비교하여 고집적도, 빠른 신호전달, 낮은 전력소비 등의 장점을 가지고 있어 많은 연구가 진행되고 있다. TSV의 세부 공정 중 비아필링(Via filling)기술은 I/O수 증가와 미세피치화에 따른 비아(Via) 직경의 감소 및 종횡비(Via Aspect Ratio)증가로 인해 기존 필링 공정으로는 한계가 있다. 기존의 비아 홀(Via hole)에 금속을 필링하기 위한 방법으로 전기도금법이 많이 사용되고 있으나, 전기도금법은 전기도금액 조성, 첨가제의 종류, 전류밀도, 전류모드 등에 따라 결과물에 큰 차이가 발생되어, 최적공정조건의 도출이 어렵다. 또한 20um이하의 비아직경과 높은 종횡비로 인하여 충진시 void형성등의 문제점이 발생하기도 한다. 본 연구에서는 용융솔더와 진공을 이용하여 비아를 필링시켰다. 이 방법은 관통된 비아가 형성된 웨이퍼 양단에 압력차를 주어, 작은 직경을 갖는 비아 홀의 표면장력을 극복하고, 용융상태의 솔더가 관통된 비아 홀 내부로 필링되는 방법이다. 관통 비아홀이 형성 된 웨이퍼 위에 솔더페이스트를 $250^{\circ}C$이상 온도를 가해 용융상태로 만든 후 웨이퍼 하부에 진공을 형성하여 필링하는 방법과 용융솔더를 노즐을 통하여 위쪽으로 유동시켜 그 위에 비아홀이 형성된 웨이퍼를 접촉하고 웨이퍼 상부에 진공을 형성하여 필링하는 방법으로 실험을 각각 실시하였다. 이 때, 웨이퍼 두께는 100um이하이며 홀 직경은 20, 30um, 웨이퍼 상부와 하부의 진공차는 약 0.02~0.08Mpa, 진공 유지시간은 1~3s로 실시하여 최적 조건을 고찰하였다. 각 조건에 따른 필링 후 단면을 전자현미경(FE-SEM)을 통해 관찰하였다. 실험 결과 0.04Mpa 이상에서 1s내의 시간에 모든 비아홀이 기공(Void)없이 완벽하게 필링되는 것을 관찰하였으며 이 결과는 기존의 방법에 비하여 공정시간을 감소시켜 생산성이 대폭 향상 될 수 있는 방법임을 확인하였다.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.5-5
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• 2008

Spinoglenoid cyst of the shoulder is a rare clinical entity and several treatment modalities have been reported. Recently, arthroscopy is effectively used via communication hole or posterior capsulotomy through the glenohumeral joint. With this method, the complete cystectomy is impossible if the cyst is a large size or extended anteriorly and there are few reports about such cases. We present extra-articular complete cystectomy through bursal space in 3 cases of huge and anteriorly extended spinoglenoid cysts. All patients were able to return to work with no restrictions and 2 patients who performed the follow up MRI demonstrated complete resolution of the cyst and some recovery of the mass of infraspinatus muscle.