• Journal of Welding and Joining
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• 제20권6호
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• pp.783-788
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• 2002

Sn-Ag-Cu solder is known as most competitive in many kinds of Pb-free solders. In this study, effects of solderability with plated layers such as Cu, Cu/Sn, Cu/Ni and Cu/Ni/Au were investigated. Sn-3.5Ag-0.7Cu solder balls were reflowed in commercial reflow machine (peak temp.:$250^{\circ}C$and conveyer speed:0.6m/min). In wetting test, immersion speed was 5mm/sec., immersion time 5sec., immersion depth 4mm and temperature of solder bath was $250^{\circ}C$. Wettability of Sn-3.5Ag-0.7Cu on Cu, Cu/Sn ($5\mu\textrm{m}$), Cu/Ni ($5\mu\textrm{m}$), and Cu/Ni/Au ($5\mu\textrm{m}/500{\AA}$) layers was investigated. Cu/Ni/Au layer had the best wettability as zero cross time and equilibrium force, and the measured values were 0.93 sec and 7mN, respectively. Surface tension of Sn-3.5Ag-0.7Cu solder turmed out to be 0.52N/m. The thickness of IMC is reduced in the order of Cu, Cu/Sn, Cu/Mi and Cu/Ni/Au coated layer. Shear strength of Cu/Ni, Cu/Sn and Cu was around 560gf but Cu/Ni/Au was 370gf.

• 마이크로전자및패키징학회지
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• 제9권2호
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• pp.1-9
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• 2002

실제 BGA패키지에서 Sn-Ag-(Cu) 솔더와 금속패드가 반응하여 생성된 금속간 화합물의 특성을 Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS)f) X-ray Diffractometer (XRD)를 사용하여 분석하였다. EDS로 분석한 결과를 보면 BGA 패키지에서 Sn-Ag-Cu 솔더와 Au/Ni/Cu 금속층간의 반응으로 생성된 금속간화합물은 $(Cu,Ni)_6Sn_5$로 예상되며 . Cu의 편석은 솔더와 Ni 층 사이에서 발견되었다. XRD 분석결과 Cu를 함유하고 있는 Sn-Ag-Cu 솔더와 Ni층 사이에서는 $\eta -Cu_6 Sn_5$ 타입의 금속간화합물이 분석되었으며 Sn-Ag 솔더와 Ni층 사이에서는 $Ni_3$Sn_4$가 분석되었다. 계면에 생성된 금속간화합물은 리플로 회수와솔더내의 Cu의 함량에 따라증가하였다

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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• pp.84-87
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• 2003

Since Pb-free solder alloys have been used extensively in microelectronic packaging industry, the interaction between UBM (Under Bump Metallurgy) and solder is a critical issue because IMC (Intermetallic Compound) at the interface is critical for the adhesion of mechanical and the electrical contact for flip chip bonding. IMC growth must be fast during the reflow process to form stable IMC. Too fast IMC growth, however, is undesirable because it causes the dewetting of UBM and the unstable mechanical stability of thick IMC. UP to now. Ni and Cu are the most popular UBMs because electroplating is lower cost process than thin film deposition in vacuum for Al/Ni(V)/Cu or phased Cr-Cu. The consumption rate and the growth rate of IMC on Ni are lower than those of Cu. In contrast, the wetting of solder bumps on Cu is better than Ni. In addition, the residual stress of Cu is lower than that of Ni. Therefore, the alloy of Cu and Ni could be used as optimum UBM with both advantages of Ni and Cu. In this paper, the interfacial reactions of Sn-3.5Ag-0.7Cu solder on Ni-xCu alloy UBMs were investigated. The UBMs of Ni-Cu alloy were made on Si wafer. Thin Cr film and Cu film were used as adhesion layer and electroplating seed layer, respectively. And then, the solderable layer, Ni-Cu alloy, was deposited on the seed layer by electroplating. The UBM consumption rate and intermetallic growth on Ni-Cu alloy were studied as a function of time and Cu contents. And the IMCs between solder and UBM were analyzed with SEM, EDS, and TEM.

• 한국자기학회지
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• 제7권1호
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• pp.19-24
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• 1997

적층형 chip inductor 소재인 NiCuZn ferrite의 제조 공정 조건 및 조성을 선정하였다. NiCuZn ferrite의 NiO 함량이 증가할 수록 저온 소결에 필요한 Fe$_{2}$O$_{3}$ 결핍량은 점차 증가하였고, NiO 함량과 Co$_{3}$O$_{4}$ 첨가량을 변화하여 투자율을 12 ~ 562 범위에서 제어할 수 있었다. NiCuZn ferrite의 투자율이 562에서 60으로 변화함에 따라서 Q$_{max}$ 주파수는 3 MHz에서 50 MHz 범위로 제어할 수 있었다. 이때 Q$_{max}$ 주파수(Y)와 투자율(X)은 log Y = 4.2-1.4 log X의 상관관계를 나타내었다.

• 한국재료학회지
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• 제20권6호
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• pp.338-343
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• 2010

As an alternative to the W plug used in MOSFETs, a Cu plug with a NiSi contact using Ta / TaN as a diffusion barrier is currently being considered. Conventionally, Ni was first deposited and then NiSi was formed, followed by the barrier and Cu deposition. In this study, Ti was employed as a barrier material and simultaneous formation of the NiSi contact and Cu plug / Ti barrier was attempted. Cu(100 nm) / Ti / Ni(20 nm) with varying Ti thicknesses were deposited on a Si substrate and annealed at $4000^{\circ}C$ for 30 min. For comparison, Cu/Ti/NiSi thin films were also formed by the conventional method. Optical Microscopy (OM), Scanning Probe Microscopy (SPM), X-Ray Diffractometry (XRD), and Auger Electron Microscopy (AES) analysis were performed to characterize the inter-diffusion properties. For a Ti interlayer thicker than 50 nm, the NiSi formation was incomplete, although Cu diffusion was inhibited by the Ti barrier. For a Ti thickness of 20 nm and less, an almost stoichiometric NiSi contact along with the Cu plug and Ti barrier layers was formed. The results were comparable to that formed by the conventional method and showed that this alternative process has potential as a formation process for the Cu plug/Ti barrier/NiSi contact system.

• 한국자기학회지
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• 제9권5호
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• pp.251-255
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• 1999

4$^{\circ}$기울어진 Si(111) 웨이퍼를 기판으로 사용하여 Cu(50$\AA$) 바닥층 위에 외부 자장의 인가없이 iFe(60$\AA$)/Co(0$\AA$$\leq$x$\AA$$\leq$15$\AA$)/Cu(60$\AA$)/Co(30$\AA$) 스핀밸브 박막을 형성하여, NiFe/Cu 계면에 삽입된 Co 층에 따른 스핀밸브 박막의 거대자기저항 특성의 변화와 NiFe 층의 자기이방성의 변화를 관찰하였다. NiFe/Cu 계면에 극히 얇은 Co층이 삽입됨에 따라, 스핀밸브 박막의 자기저항비는 약 1.5%에서 3.5%로 약 2배이상 증가하였고, NiFe층의 자화용이축이 90$^{\circ}$전이하여 Co(30$\AA$)층의 자화용이축과 같은 방향으로 정렬됨이 관찰되었다. 따라서, 극히 얇은 Co 층이 NiFe/Cu 계면에 삽입된 스핀밸브 박막에서 향상된 각형성(squareness)을 나타내는 자기저항곡선을 관찰할 수 있었으며, 이는 MRAM을 비롯한 디지털 자기저항소자 응용에 적합한 것으로 판단되었다. 또한, NiFe 박막을 동일한 기판과 바닥층에 형성하여, NiFe 박막과 Cu 바닥층이 이루는 계면에 Co 층의 삽입 유무에 따른 XRD 측정을 한 결과, NiFe/Cu 계면에 존재하는 Co층에 상관없이 NiFe 박막은(220) 배향을 타나냈었으며, 이로부터 극히 얇은 Co층의 삽입에 따른 NiFe층의 자기이방성의 변화는 NiFe/Cu 계면에서 NiFe/Co 계면으로 바뀜에 따른 계면 효과에 의한 것으로 사료되었다.

• 대한화학회지
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• 제53권3호
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• pp.233-243
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• 2009

실리카지지 니켈(Ni-Si$O_2$), 실리카지지 구리(Cu-Si$O_2$), 몇가지 조성의 실리카지지 니켈과 구리의 합금(Ni/Cu-Si$O_2$)을 실온에서 일산화탄소(CO)의 압력을 넓은 범위에서 변화시키면서(0.2 $torr{\sim}$50 torr) 흡착된 CO의 적외선 스펙트럼을 1500 $cm^{-1}{\sim}2500\;cm^{-1}$ 범위에서 관찰했고 실온에서 진공탈착시키면서 흡착된 CO의 적외선 스펙트럼을 관찰했다. Ni-Si$O_2$에 CO를 흡착시켰을 때 2059.6 $cm^{-1},\;{\sim}$2036.5 $cm^{-1},\;{\sim}$1868.7 $cm^{-1},\;{\sim}$1697.1 $cm^{-1}$의 네 흡수띠가 관찰되었고, Cu-Si$O_2$에 일산화탄소를 흡착시켰을 때 $\sim$2115.5 $cm^{-1},\;{\sim}$1743.0 $cm^{-1}$ 두 흡수띠가 관찰되었으며, Ni/Cu-Si$O_2$에서는 ${\sim}2123.2\;cm^{-1}$, 2059.6 $cm^{-1},\;{\sim}$2036.4 $cm^{-1},\;{\sim}$1899.5 $cm^{-1},\;{\sim}$1697.1 $cm^{-1}$에 다섯 흡수띠가 관찰되었다. Ni/Cu-Si$O_2$, Cu-Si$O_2$, Ni/Cu-Si$O_2$에서 CO를 흡착시켰을 때 관찰된 흡수스펙트럼은 이전의 보고와 근사적으로 일치한다. 1800 $cm^{-1}$ 이하의 흡수띠는 Ni이나 Ni/Cu 합금의 스텦이 있는 결정표면에서 관찰된 바 있는데 Ni-Si$O_2$, Ni/Cu-Si$O_2$를 실온에서 CO를 흡착시켰을 때 나타나는 ${\sim}1697.1\;cm^{-1}$ 흡수띠는 Ni이나 Ni/Cu 합금 표면에서 스텦에 인접한 흡착자리에 흡착한 CO에 기인한 흡수띠로 제시할 수 있다. Cu-Si$O_2$ 시료를 실온에서 CO를 흡착시켰을 때 Cu 결정표면에서 2000 $cm^{-1}$ 이하의 흡수띠가 관찰되는 경우는 드문데 1743.0 $cm^{-1}$ 흡수띠는 Cu 표면의 스텦에 인접한 흡착자리에 흡착한 CO에 기인한 흡수띠로 제시할 수 있다. Ni/Cu-Si$O_2$에서 Cu의 함량이 몰분율 0.5까지 변함에 따라 같은 CO 압력 또는 같은 진공탈착시간에서 흡수띠의 위치가 21 $cm^{-1}$ 이하로 다른 ⅠB 금속을 첨가했을 때보다 작게 변하는데 Cu d 전자의 리간드 효과가 작은 현상에 기인한 것으로 볼 수 있다.

• 대한금속재료학회지
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• 제50권6호
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• pp.419-425
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• 2012

The purpose of this research was to develop a low Ni austenitic cast iron through replacing Ni by Cu and Mn because they are cheaper than Ni. The effect of the Cu content (6-12 wt%) on the microstructure characteristics was investigated in Fe-3%C-16%(Ni+Cu+Mn) cast iron. Contrary to general effect of the Cu on cast iron, the result of the microstructure analysis indicated that bainite and cementite were formed in high Cu content (>8 wt%Cu). A crystallized Cu-solution (Cu-Mn) phase and MnS in the Cu-solution were formed. The quantity of those phases increased as the Cu content increased. Consequently, the high Cu content in the composition ratio (Ni+Cu+Mn=16%) caused the formation of Cu-Mn/MnS and those phases decreased the effect of Cu and Mn on austenite formation. For this reason, bainite and cementite were formed in high Cu content.

• E2M - 전기 전자와 첨단 소재
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• 제10권9호
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• pp.938-944
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• 1997

Cu-Ni thin film strain gauges for diaphragm-type pressure sensors were developed. Thin films of Cu-Ni alloys of various compositions were deposited onto glass and stainless steel substrates by RF magnetron sputtering. The effects of composition substrate temperature Ar partial pressure and aging on the electrical properties of Cu-Ni film strain gauges in the thickness range 500~2000$\AA$ are discussed. The maximum resistivity(95.6 $\mu$$\Omega$cm) is obtained from 53wt%Cu-47wt%Ni films while the temperature coefficient of resistance(TCR) becomes minimum(25.6ppm/$^{\circ}C$). The gauge factor is about 1.9.

• Applied Microscopy
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• 제45권1호
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• pp.9-15
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• 2015

In the present study, microstructural evolution in CuCrFeNi, CuCrFeNiMn, and CuCrFeNiMnAl alloys has been investigated. The as-cast CuCrFeNi alloy consists of a single fcc phase with the lattice parameter of 0.358 nm, while the as-cast CuCrFeNiMn alloy consists of (bcc+fcc1+fcc2) phases with lattice parameters of 0.287 nm, 0.366 nm, and 0.361 nm. The heat treatment of the cast CuCrFeNiMn alloy results in the different type of microstructure depending on the heat treatment temperature. At $900^{\circ}C$ a new thermodynamically stable phase appears instead of the bcc solid solution phase, while at $1,000^{\circ}C$, the heat treated microstructure is almost same as that in the as-cast state. The addition of Al in CuCrFeNiMn alloy changes the constituent phases from (fcc1+fcc2+bcc) to (bcc1+bcc2).