• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권7호
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• pp.311-315
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• 2002

Chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric(IMD), inter-level dielectric (ILD) layers of multi-layer interconnections. In this paper, we studied the characteristics of polishing pad, which can apply shallow trench isolation (STI)-CMP process for global planarization of multi-level interconnection structure. Also, we investigated the effects of different sets of polishing pad, such as soft and hard pad. As an experimental result, hard pad showed center-fast type, and soft pad showed edge-fast type. Totally, the defect level has shown little difference, however, the counts of scratch was detected less than 2 on JR111 pad. Through the above results, we can select optimum polishing pad, so we can expect the improvements of throughput and device yield.

• 마이크로전자및패키징학회지
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• 제22권3호
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• pp.51-56
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• 2015

솔더 조인트의 신뢰성 강화를 위해서 다양한 pad finish material이 사용되고 있으며, 최근에는 Electroless Ni Electroless Pd Immersion Gold (이하 ENEPIG) pad가 많이 사용되고 있다. 따라서, 본 연구는 상용화 되어 사용중인 Electrolytic Ni (soft Ni) pad와 최근 이슈가 되고 있는 ENEPIG pad에 대한 신뢰성 평가에 관한 것으로, 다양한 Cu 함량에 따른 거동을 관찰 하였다. Reflow 후 솔더와 pad간의 접합층은 $Cu_6Sn_5$에 Ni이 치환된 형태의 금속간 화합물로 구성되어 있었으며, ENEPIG pad의 경우, 접합층과 Ni layer 사이에 $Ni_3P$ (dark layer) layer가 관찰 되었다. 또한, Cu 함량에 따라 Dark layer의 두께를 제어할 수 있었다. 충격 낙하 시험 후, 파괴모드를 관찰한 결과 soft Ni pad와 ENEPIG pad에서 서로 다른 파괴모드가 관찰 되었으며, soft Ni의 경우, 1차 IMC와 2차 IMC 경계에서 파괴가 관찰 되었고, ENEPIG pad의 경우, dark layer에서 파괴가 관찰 되었다. IMC와 pad material, bulk 솔더와의 lattice mismatch에 의해 불안정한 계면이 존재하며, 이는 연속적인 외부 충격에 의해 가해진 열적, 물리적 스트레스를 IMC 계면으로 전송하기 때문에, 솔더의 신뢰성 향상을 위해서는 솔더 벌크의 제어와 IMC의 두께 및 형상의 제어는 필요하다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.54-57
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• 2001

We studied the characteristics of polishing pad, which can apply STI-CMP process for global planarization of multilevel interconnection structure. Also, we investigated the effects of different sets of polishing pad, such as soft and hard pad. As an experimental result, hard pad showed center-fast type, and soft pad showed edge-fast type. Totally, the defect level has shown little difference, however, the counts of scratch was defected less than 2 on JRlll pad. Through the above results, we can select optimum polishing pad, so we can expect the improvements of throughput and devise yield.

• 대한치과의사협회지
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• 제47권3호
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• pp.122-130
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• 2009

For the successful guided bone regeneration(GBR) of maxillary bony defect, proper soft tissue coverage is one of the most important things. Soft tissue dehiscence can be most common reason of osseous reconstruction failure. If a vascular supply to the graft should not develop from the host tissue, then the graft may also foil. Both of these prerequisites can be aided by judicious use of the buccal fat pad(BFP). Many methods for adequate soft tissue coverage have been proposed and the use of the BFP is one of them. BFP is useful in posterior maxillary area, can cover larger area and have higher blood flow than other methods. so the use of the BFP may offer protection and early blood supply to maxillary bone graft. This report describes the history, anatomy, blood flow, and clinical usefulness with two clinical cases.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.433-434
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• 2002

Chemical mechanical polishing refers to a process by which silicon and partially-processed integrated circuits (IC's) built on silicon substrates are polished to produce planar surfaces for the continued manufacturing of IC's. Chemical mechanical polishing is done by pressing the silicon wafer, face down, onto a rotating platen that is covered by a rough polyurethane pad. During rotation, the pad is flooded with a slurry that contains nanoscale particles. The pad deforms and the roughness of the surface entrains the slurry into the interface. The asperities contact the wafer and the surface is polished in a three-body abrasion process. The contact of the wafer with the 'soft' pad produces a unique elastohydrodynamic situation in which a suction force is imposed at the interface. This added force is non-uniform and can be on the order of the applied pressure on the wafer. We have measured the magnitude and spatial distribution of this suction force. This force will be described within the context of a model of the sliding of hard surfaces on soft substrates.

• Archives of Plastic Surgery
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• 제38권4호
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• pp.415-420
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• 2011

Purpose: The reconstruction of a soft tissue defect of the heel pad can be challenging. One vital issue is the restoration of the ability of the heel to bear the load of the body weight. Many surgeons prefer to use local flaps or free tissue transfer rather than a skin graft. In this study, we evaluated the criteria for choosing a proper flap for heel pad reconstruction. Methods: In this study, 23 cases of heel pad reconstruction were performed by using the flap technique. The etiologies of the heel defects included pressure sores, trauma, or wide excision of a malignant tumor. During the operation, the location, size and depth of the heel pad defect determined which flap was chosen. When the defect size was relatively small and the defect depth was limited to the subcutaneous layer, a local flap was used. A free flap was selected when the defect was so large and deep that almost entire heel pad had to be replaced. Results: There was only one complication of poor graft acceptance, involving partial flap necrosis. This patient experienced complete recovery after debridement of the necrotic tissue and a split thickness skin graft. None of the other transferred tissues had complications. During the follow-up period, the patients were reported satisfactory with both aesthetic and functional results. Conclusion: The heel pad reconstructive method is determined by the size and soft-tissue requirements of the defect. The proper choice of the donor flap allows to achieve satisfactory surgical outcomes in aesthetic and functional viewpoints with fewer complications.

• Journal of Korean Dental Science
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• 제7권1호
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• pp.38-42
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• 2014

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is defined as exposed necrotic bone without evidence of healing for at least 8 weeks in the maxillofacial area in a patient with history of bisphosphonate use. Obtaining complete coverage of the hard tissue by soft tissue in BRONJ patients is especially important. Therefore, managing the mucosa is one of the key factors in a successful outcome, but this is especially hard to achieve in BRONJ patients. Various applications of buccal fat pad in oral reconstruction-including the closure of surgical defects following tumor excision, repair of surgical defects following the excision of leukoplakia and submucous fibrosis, closure of primary and secondary palatal clefts, coverage of maxillary and mandibular bone grafts, and lining of sinus surface of maxillary sinus bone graft in sinus lift procedures for maxillary augmentation-have been studied. Eliminating all potential sites of infection and post-operative infection control is crucial in BRONJ. We present a case using the buccal fat pad pedicle for a stage 3 BRONJ defect. Uneventful total epithelialization of the buccal fat pad regardless of size was noted. In summary, the buccal fat pad has versatile application and various recipient sites for surgical utilization. It is an easy technique, with promising overall success rates. With careful selection and handling, buccal fat graft can resolve problems with soft tissue coverage in stage 2 or 3 BRONJ patients.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.381-386
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• 2000

The brake force of drum brakes for commercial vehicles is applied by a s-cam. First of all the influence of the s-cam load angles and elastic modulus of the pad on the contact pressure distribution between pad and drum was checked by using 3 dimensional finite element model. In the second part, temperature and thermal stress analyses were carried out by an axisymmetric model with constant heat flux and pressure-proportional heat flux. In the case of temperature analysis the heat conduction from the interface to the pad and the drum was modeled using a thin soft film element, so artificial division of the generated heat flux between pad and drum is not necessary. The analysis was performed by ABAQUS/Standard code.

• 한국전기전자재료학회논문지
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• 제18권4호
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• pp.313-320
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• 2005

Stick-slip friction is one of the material removal mechanisms in tribology. It occurs when the static friction force is larger than the dynamic friction force, and make the friction curve fluctuated. In the friction monitoring of chemical mechanical polishing(CMP), the friction force also vibrates just as stick-slip friction. In this paper, an attempt to show the similarity between stick-slip friction and the friction of CMP was conducted. The prepared hard pa(IC1000/Suba400 stacked/sup TM/) and soft pad(Suba400/sup TM/) were tested with SiO₂ slurry. The friction force was measured by piezoelectric sensor. According to this experiment, it was shown that as the head and table velocity became faster, the stick-slip time shortened because of the change of real contact area. And, the gradient of stick-slip period as a function of head and table speed in soft pad was more precipitous than that of hard one. From these results, it seems that the fluctuating friction force in CMP is stick-slip friction caused by viscoelastic behavior of the pad and the change of real contact area.

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2009년도 춘계학술대회
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• pp.36-36
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• 2009