• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.45-50
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• 2014

Effects of wet chemical treatment and thermal cycle conditions on the quantitative interfacial adhesion energy of $Cu/SiN_x$ thin film interfaces were evaluated by 4-point bending test method. The test samples were cleaned by chemical treatment after Cu chemical-mechanical polishing (CMP). The thermal cycle test between Cu and $SiN_x$ capping layer was experimented at the temperature, -45 to $175^{\circ}C$ for 250 cycles. The measured interfacial adhesion energy increased from 10.57 to $14.87J/m^2$ after surface chemical treatment. After 250 thermal cycles, the interfacial adhesion energy decreased to $5.64J/m^2$ and $7.34J/m^2$ for without chemical treatment and with chemical treatment, respectively. The delaminated interfaces were confirmed as $Cu/SiN_x$ interface by using the scanning electron microscope and energy dispersive spectroscopy. From X-ray photoelectron spectroscopy analysis results, the relative Cu oxide amounts between $SiN_x$ and Cu decreased by chemical treatment and increased after thermal cycle. The thermal stress due to the mismatch of thermal expansion coefficient during thermal cycle seemed to weaken the $Cu/SiN_x$ interface adhesion, which led to increased CuO amounts at Cu film surface.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.151-151
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• 1999

금속-산화막-반도체(MOS) 소자를 이용하는 집적회로의 발전은 게이트 금속의 규격 감소를 필요로 한다. 규격감소에 따른 저항 증가가 중요한 문제점으로 대두되었으며, 그동안 여러 연구자들에 의하여 금속 게이트에 관련된 연구가 진행되어 왔다. 특히 저항이 낮으며 녹는점이 매우 높은 내화성금속(refractory metal)인 텅스텐(tungsten, W)이 차세대 MOS 소자의 유력한 대체 게이트 금속으로 제안되었다. 텅스텐은 스퍼터링(sputtering)과 화학기상 증착(CVD) 방식을 이용하여 성장시킬 수 있다. 스퍼터링에 의한 텅스텐 증착은 산화막과의 접착성은 우수한 반면에 증착과정 동안에 게이트 산화막(SiO2)에 손상을 주어 게이트 산화막의 특성을 열화시킬 수 있다. 반면, 화학기상 증차에 의한 텅스텐 성장은 스퍼터링보다 증착막의 저항이 상대적으로 낮으나 산화막과의 접착성이 좋지 않은 문제를 해결하여야 한다. 본 연구에서는 감압 화학기상 증착(LPCVD)방식을 이용하여 텅스텐 게이트 금속을 100~150$\AA$ 두께의 게이트 산화막(SiO2 또는 N2O 질화막)위에 증착하여 물리 및 전기적 특성을 분석하였다. 물리적 분석을 위하여 XRD, SEM 및 저항등이 증착 조건에 따라서 측정되었으며, 텅스텐 게이트로 구성된 MOS 캐패시터를 제작하여 절연 파괴 강도, 전하 포획 메커니즘 등과 같은 전기적 특성 분석을 실시하였다. 특히 텅스텐의 접착성을 증착조건의 변화에 따라서 분석하였다. 텅스텐 박막의 SiO2와의 접착성은 스카치 테이프 테스트를 실시하여 조사되었고, 증착시의 기판의 온도에 민감하게 반응하는 것을 알 수 있었다. 또한, 40$0^{\circ}C$ 이상에서 안정한 것을 볼 수 있었다. 텅스텐 박막은 $\alpha$ 및 $\beta$-W 구조를 가질 수 있으나 본 연구에서 성장된 텅스텐은 $\alpha$-W 구조를 가지는 것을 XRD 측정으로 확인하였다. 성장된 텅스텐 박막의 저항은 구조에 따라서 변화되는 것으로 알려져 있다. 증착조건에 따른 저항의 변화는 SiH4 대 WF6의 가스비, 증착온도에 따라서 변화하였다. 특히 온도가 40$0^{\circ}C$ 이상, SiH4/WF6의 비가 0.2일 경우 텅스텐을 증착시킨 후에 열처리를 거치지 않은 경우에도 기존에 발표된 저항률인 10$\mu$$\Omega$.cm 대의 값을 얻을 수 있었다. 본 연구를 통하여 산화막과의 접착성 문제를 해결하고 낮은 저항을 얻을 수 있었으나, 텅스텐 박막의 성장과정에 의한 게이트 산화막의 열화는 심각학 문제를 야기하였다. 즉, LPCVD 과정에서 발생한 불소 또는 불소 화합물이 게이트의 산화막에 결함을 발생시킴을 확인하였다. 향후, 불소에 의한 게이트 산화막의 열화를 최소화시킬 수 있는 공정 조건의 최저고하 또는 대체게이트 산화막이 적용될 경우, 개발된 연구 결과를 산업체로 이전할 수 있는 가능성이 높을 것을 기대된다.

• Journal of Adhesion and Interface
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• v.11 no.2
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• pp.41-49
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• 2010

Furan-containing epoxide monomers (8, 9) were designed and synthesized as carbon-neutral, environment-friendly adhesion material. Bicyclic skeleton were constructed using the Diels-Alder reaction of furan and methyl acrylate, both readily accessible starting material from a biomass via bio-refinery process. After reduction of ester functionality, resulting hydroxyl moieties were coupled to epichlorohydrin to provide the epoxy-functionalized furanic monomers (8, 9). The structure of new furanic monomers was confirmed by $^1H$ and $^{13}C$ NMR spectroscopy. As UV-curable monomers, basic properties such as UV curing time and the extent of UV curing were evaluated by photo DSC. Photo-curing shrinkages were measured by linear variable differential transformer transducer (LVDT) and the effect of molecular structure on shrinkage was considered. In addition, new synthetic compounds showed the shear strength over 3 MPa when they were photo-cured between polycarbonate plates, which indicates these compounds are feasible to use as photo-curable adhesive materials.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.1-8
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• 2019

The demand and importance of adhesives and paint coatings applied to solid surfaces such as metals, ceramics, and plastics are increasing. In this study, the influencing factors on the adhesive strength between the polymer coating and the metal adherend were investigated by Dolly test when the adhesive or the paint coating was applied on the metal adherend. Two-component epoxy adhesive was used as the adhesive, and EH2350, a two-component epoxy paint for anti-corrosion, was used as the paint. Especially, the effect of adherend metals(Al, Fe, STS, Cu, Zn), surface roughness and surface contamination(tap water, salt water) on adhesive strength was studied as influencing factors. The adhesive strength between adhesive and adherend was different when the type of metal adherend was different even when the same adhesive was used. It was found that spray water cleaning was necessary before the paint coating process on the surface of the oxide contaminated adherend with tap water or salt water. As a result of this study, it was confirmed that Dolly test can be widely used in the future to measure adhesive strength between paint coating and adherend.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.261-267
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• 2020

The demand for faster, lighter, and thinner portable electronic devices has brought about a change in semiconductor packaging technology. In response, a stacked chip-scale package(SCSP) is used widely in the assembly industry. One of the key materials for SCSP is a die-attach film (DAF). Excellent flowability is needed for DAF for successful die attachment without voids. For DAF with high flowability, two-step curing is often required to reduce a cure crack, but one-step curing is needed to reduce the processing time. In this study, DAF composition was categorized into three groups: cure (epoxy resins), soft (rubbers), hard (phenoxy resin, silica) component. The effect of the composition on a cure crack was examined when one-step curing was applied. The die-attach void and flowability were also assessed. The cure crack decreased as the amount of hard components decreased. Die-attach voids also decreased as the amount of hard components decreased. Moreover, the decrease in cure component became important when the amount of hard component was small. The flowability was evaluated using high-temperature storage modulus and bleed-out. A decrease in the amount of hard components was critical for the low storage modulus at 100℃. An increase in cure component and a decrease in hard component were important for the high bleed-out at 120℃(BL-120).

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.46.2-46.2
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• 2009

휴대전화, 랩톱 컴퓨터 등 각종 모바일기기 및 디스플레이 기기의 경박단소화 및 고기능화에 따라 연성회로기판(FPCB)의 사용량이 증가하고있다. 연성회로기판의 핵심소재인 동박적층필름(FCCL)은 폴리이미드필름과 접착층, Cu 층으로 구성되는데, 이 중접착층으로 사용되는 Ni-20Cr합금은 에칭공정 후 Cr의 잔류에 의해 불량률 증가가 문제되고 있어, Ni-Cr합금 스퍼터링 타깃의 Cr 함량 저감 또는 Cr-free Ni합금 개발 등이 요구되고 있다. 본 연구에서는 차세대 FCCL 본드층에 적합한 Ni기 합금을 개발하기 위한 기초연구로써 Cr 함량 및 가공열처리조건에 따른 미세조직과 집합조직 변화를 조사하였다. 4N급의 고순도Ni과 Cr을 진공 플라즈마 용해장치로 용해하여Ni-xCr (x=5, 10, 15, 20wt.%)합금 잉곳을 만들고, 이를 두께감소율 90%로 냉간압연한 후, $600^{\circ}C$ 및 $800^{\circ}C$에서 10~120분 동안 어닐링하여 시편을 준비하였다. 광학현미경으로 미세조직을 관찰하고, Micro-Vickers 경도시험을 통해 어닐링 조건에 따른 경도변화를 조사하였다. 또한 SEM-EBSD를 이용하여 집합조직 및 입계특성을 분석하였다. $600^{\circ}C$ 어닐링 시 Cr함량이 증가할수록 재결정 완료시간이 증가하여 Ni-20Cr합금의 경우 2시간이상 어닐링에도 재결정이 일어나지 않았다. $800^{\circ}C$ 어닐링 시 10분 어닐링 조건에서 4종류 합금 모두 재결정이 완료되었으며, 동일한 어닐링 조건에서 Cr함량이 증가할수록 결정립이 작아지는 것으로 나타났다. $800^{\circ}C$ 2시간 어닐링 조건에서 Ni-5Cr 합금의 주요 집합조직은 {223}<113>과 {122}<112>로 나타났으며, 이중 {223}<113>은Cr 함량이 증가함에 따라 점차 {122}<112>에 가까운 방향으로 변화되어 Ni-20Cr 합금의 경우 {123}<112>만이 형성되었다. 이러한 집합조직의 변화는 적층결함에너지 감소에 의한 ${\Sigma}3$ 입계의 분율 증가와 밀접한 관련이 있는 것으로 사료된다.

• Journal of the Korean Ceramic Society
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• v.39 no.10
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• pp.1001-1006
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• 2002

Bond strength of $SrZrO_3$ resistive oxide barrier on Ag sheathed Bi(2223) tapes prepared by the sol-gel and dip-coating method was evaluated with an aid of Taguchi method and $L_18(2^1{\times}3^7)$ orthogonal arrays to determine the optimal process combination of levels of factors that best satisfy the bigger is better quality characteristic. The observed optimal condition is as follows: Sr/Zr mol ratio(0.3/0.7), amount of organic vehicle(5 wt%), drying temperature and time(160${\circ}C$, 10 min), heat treatment temperature and time(500${\circ}C$, 20 min), respectively. ANOVA analysis suggested that the influence of the factors within ${\alpha}$=0.1 was significant with a 90% confidence level.

• Journal of Adhesion and Interface
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• v.18 no.3
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• pp.118-126
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• 2017

In a natural fiber-reinforced composite material, many studies have been devoted to improving the interfacial adhesion between natural fiber and polymer matrix and the composite properties through various fiber surface modifications. In the present study, waste wool-reinforced polypropylene matrix composites were fabricated by compression molding and their mechanical and impact properties were characterized. As a result, the tensile and flexural properties and the impact strength of waste wool/polypropylene composites strongly depended on the treatment medium, alkali treatment with sodium hydroxide (NaOH) and silane treatment with 3-glycidylpropylsilane(GPS). The composite with waste wool by silane treatment exhibited higher mechanical properties and impact resistance than that by alkali treatment. The fracture surfaces of the composites support qualitatively the increased properties, showing the improved interfacial bonding between the waste wool and the polypropylene matrix.

• Composites Research
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• v.26 no.2
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• pp.129-134
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• 2013

The strength of adhesive joints employed in composite structures under cryogenic environments, such as LNG tanks, is affected by thermal residual stress generated from the large temperature difference between the bonding process and the operating temperature. Aramid fibers are noted for their low coefficient of thermal expansion (CTE) and have been used to control the CTE of thermosetting resins. However, aramid composites exhibit poor adhesion between the fibers and the resin because the aramid fibers are chemically inert and contain insufficient functional groups. In this work, electrospun meta-aramid nanofiber-reinforced epoxy adhesive was fabricated to improve the interfacial bonding between the adhesive and the fibers under cryogenic temperatures. The CTE of the nanofiber-reinforced adhesives were measured, and the effect on the adhesion strength was investigated at single-lap joints under cryogenic temperatures. The fracture toughness of the adhesive joints was measured using a Double Cantilever Beam (DCB) test.

• Journal of the Korean Wood Science and Technology
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• v.30 no.1
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• pp.1-10
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• 2002

The aim of this research was to investigate the manufacturing possibility of the paper sludge-synthetic fiber-wood fiber composite. Three levels of the formulation of paper sludge, synthetic fiber and wood fiber (5:5:90, 15:15:70, 25:25:50), two types of adhesive (PMDI, urea-formaldehyde resin) and three levels of density(0.7, 0.8, 0.9) were designed. From the test result, composites with similar or better properties, when compared with commercial fiberboard, appeared to be possible by the addition of up to 30~50% paper sludge and synthetic fiber into wood fiber.