• Clean Technology
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• v.27 no.3
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• pp.223-231
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• 2021

In order to address many issues associated with large volume changes of silicon, which has very low electrical conductivity but offers about 10 times higher theoretical capacity than graphite (Gr), a silicon nanoparticles/hollow carbon (SiNP/HC) composite having bimodal-mesopores was prepared using silica nanoparticles as a template. A control SiNP/C composite without a hollow structure was also prepared for comparison. The physico-chemical and electrochemical properties of SiNP/HC were analyzed by X-ray diffractometry, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption measurements for surface area and pore size distribution, scanning electron microscopy, transmission electron microscopy, galvanostatic cycling, and cyclic voltammetry tests to compare them with those of the SiNP/C composite. The SiNP/HC composite showed significantly better cycle life and efficiency than the SiNP/C, with minimal increase in electrode thickness after long cycles. A hybrid composite, SiNP/HC@Gr, prepared by physical mixing of the SiNP/HC and Gr at a 50:50 weight ratio, exhibited even better cycle life and efficiency than the SiNP/HC at low capacity. Thus, silicon/carbon composites designed to have hollow spaces capable of accommodating volume expansion were found to be highly effective for long cycle life of silicon-based composites. However, further study is required to improve the low initial coulombic efficiency of SiNP/HC and SiNP/HC@Gr, which is possibly because of their high surface area causing excessive electrolyte decomposition for the formation of solid-electrolyte-interface layers.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.2
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• pp.52-59
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• 2023

The effects of dielectric curing temperature and temperature/humidity treatment conditions on the interfacial adhesion energies between Ti diffusion barrier/polybenzoxazole (PBO) dielectric layers were systematically investigated for Cu redistribution layer applications of fan-out wafer level package. The initial interfacial adhesion energies were 16.63, 25.95, 16.58 J/m² for PBO curing temperatures at 175, 200, and 225 ℃, respectively. X-ray photoelectron spectroscopy analysis showed that there exists a good correlation between the interfacial adhesion energy and the C-O peak area fractions at PBO delaminated surfaces. And the interfacial adhesion energies of samples cured at 200 ℃ decreased to 3.99 J/m² after 500 h at 85 ℃/85 % relative humidity, possibly due to the weak boundary layer formation inside PBO near Ti/PBO interface.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.49-55
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• 2016

The effects of post-annealing and temperature/humidity conditions on the interfacial adhesion energies of atomic layer deposited RuAlO diffusion barrier layer for Cu interconnects were systematically investigated. The initial interfacial adhesion energy measured by four-point bending test was $7.60J/m^2$. The interfacial adhesion energy decreased to $5.65J/m^2$ after 500 hrs at $85^{\circ}C$/85% T/H condition, while it increased to $24.05J/m^2$ after annealing at $200^{\circ}C$ for 500 hrs. The X-ray photoemission spectroscopy (XPS) analysis showed that delaminated interface was RuAlO/$SiO_2$ for as-bonded and T/H conditions, while it was Cu/RuAlO for post-annealing condition. XPS O1s peak separation results revealed that the effective generation of strong Al-O-Si bonds between $AlO_x$ and $SiO_2$ interface at optimum post-annealing conditions is responsible for enhanced interfacial adhesion energies between RuAlO/$SiO_2$ interface, which would lead to good electrical and mechanical reliabilities of atomic layer deposited RuAlO diffusion barrier for advanced Cu interconnects.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.29-37
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• 2021

The effect of Ar/N₂ two-step plasma treatment on the quantitative interfacial adhesion energy of low temperature Cu-Cu bonding interface were systematically investigated. X-ray photoelectron spectroscopy analysis showed that Ar/N₂ 2-step plasma treatment has less copper oxide due to the formation of an effective Cu4N passivation layer. Quantitative measurements of interfacial adhesion energy of Cu-Cu bonding interface with Ar/N₂ 2-step plasma treatment were performed using a double cantilever beam (DCB) and 4-point bending (4-PB) test, where the measured values were 1.63±0.24 J/m² and 2.33±0.67 J/m², respectively. This can be explained by the increased interfacial adhesion energy according phase angle due to the effect of the higher interface roughness of 4-PB test than that of DCB test.

• Composites Research
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• v.35 no.6
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• pp.394-401
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• 2022

Two polymer precursors, polyvinylidene chloride-resin (PVDC-resin) and polyvinylidene fluoride (PVDF), are assembled into the microporous carbon by pyrolysis. Microporous carbon is advantageous as an electrode for supercapacitors that store electric charges through ion adsorption/desorption. The pyrolysis also turns the various heteroatoms of two precursors into functional groups, contributing to the additional charge storage. The analysis of the porous structure and function group during carbonization are important to develop the carbon for energy storage. Here, we analyzed the functional groups of two polymer-derived carbons through X-ray photoelectron spectroscopy. The electrochemical properties of the functional groups were explored in various pH electrolytes. The specific capacitance of two carbons in the acidic electrolyte (1 M H₂SO₄) was improved compared to that in the neutral electrolyte (0.5 M Na₂SO₄) due to the faradaic charge/discharge reaction of the quinone functional group. In particular, the carbon electrode derived from PVDC-resin exhibits a lower capacity than the carbon from PVDF due to the small micropores. In the alkaline electrolyte (6 M KOH), the highest specific capacitance and rate capability were obtained among the three electrolytes for both electrodes based on the facile adsorption of the constituent electrolyte ions (K⁺, OH^-).

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.75-81
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• 2017

The effects of KOH pretreatment and annealing conditions on the interfacial adhesion and the reliability between epoxy resin and polyimide substrate in the flexible printed circuit board were quantitatively evaluated using $180^{\circ}$ peel test. The initial peel strength of the polyimide without the KOH treatment was 29.4 g/mm and decreased to 10.5 g/mm after 100hrs at $85^{\circ}C/85%$ R.H. temperature/humidity treatment. In case of the polyimide with annealing after KOH treatment, initial peel strength was 29.6 g/mm and then maintained around 27.5 g/mm after $85^{\circ}C/85%$ R.H. temperature/humidity treatment. Systematic X-ray photoelectron spectroscopy analysis results showed that the peel strength after optimum annealing after KOH treatment was maintained high not only due to effective recovery of the polyimide damage by the polyimide surface treatment process, but also effective removal of metallic ions and impurities during various wet process.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.7-12
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• 2018

The effects of Ru deposition temperature and post-annealing conditions on the interfacial adhesion energies of atomic layer deposited (ALD) Ru diffusion barrier layer and Cu thin films for the advanced Cu interconnects applications were systematically investigated. The initial interfacial adhesion energies were 8.55, 9.37, $8.96J/m^2$ for the sample deposited at 225, 270, and $310^{\circ}C$, respectively, which are closely related to the similar microstructures and resistivities of Ru films for ALD Ru deposition temperature variations. And the interfacial adhesion energies showed the relatively stable high values over $7.59J/m^2$ until 250h during post-annealing at $200^{\circ}C$, while dramatically decreased to $1.40J/m^2$ after 500 h. The X-ray photoelectron spectroscopy Cu 2p peak separation analysis showed that there exists good correlation between the interfacial adhesion energy and the interfacial CuO formation. Therefore, ALD Ru seems to be a promising diffusion barrier candidate with reliable interfacial reliability for advanced Cu interconnects.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.55-60
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• 2012

In order to develop electroless-plated Nickel Phosphate (Ni-P) as a contact material for high efficient low-cost silicon solar cells, we evaluated the effect of ambient thermal annealing on the degradation behavior of interfacial adhesion energy between electroless-plated Ni-P and silicon solar cell wafers by applying 4-point bending test method. Measured interfacial adhesion energies decreased from 14.83 to 10.83 J/$m^2$ after annealing at 300 and $600^{\circ}C$, respectively. The X-ray photoelectron spectroscopy analysis suggested that the bonding interface was degraded by environmental residual oxygen, in which the oxidation inhibit the stable formation of Ni silicide phase between electroless-plated Ni-P and silicon interface.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.39-45
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• 2012

Three-dimensional integrated circuit(3D IC) technology has become increasingly important due to the demand for high system performance and functionality. In this work, BOE and HF wet etching of Cu line surfaces after CMP were conducted for Cu-Cu pattern direct bonding. Step height of Cu and $SiO_2$ as well as Cu dishing after Cu CMP were analyzed by the 3D-Profiler. Step height increased and Cu dishing decreased with increasing BOE and HF wet etching times. XPS analysis of Cu surface revealed that Cu surface oxide layer was partially removed by BOE and HF wet etching treatment. BOE treatment showed not only the effective $SiO_2$ etching but also reduced dishing and Cu surface oxide rather than HF treatment, which can be used as an meaningful process data for reliable Cu-Cu pattern bonding characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.153-153
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• 1999

platinum 유기착화합물을 사용하여 유리 기판 위에 Pt를 증착시켰다. Pt를 증착하기 위하여 Pt 착화합물을 용해 시킨 후, 유리 기판을 용액속에 담근 후 가열하여 Pt막을 증착하였다. 증착 후 Pt의 면저항은 200~75$\Omega$의 값을 나타내어 비교적 높은 저항값을 나타내었다. 높은 저항값을 낮추기 위해 진공 10-5Torr에서 50, 100, 150, 25$0^{\circ}C$로 열처리를 하였다. 이러한 저항값을 변화의 원인을 살펴보기 위하여 X-선 회절법을 이용하여 결정성의 변화를 살펴보았고, 화학적 조성의 변화는 X-ray 광전자 분광법을 이용하여 조사하였다. 열처리 전 Pt막은 비정질 상태를 나타내었으나, 6$0^{\circ}C$에서 30분간 열처리한 후에는 결정성이 증가하는 것으로 관찰되었다. 열처리 후 결정방향은 {111] 방향이 주 방향이였으며 [002] 방향의 피크도 관찰되었다. 따라서 성장된 막은 다결정 막임을 알 수 있었다. XPS를 이용하여 조성을 조사하여 본 결과 열처리하지 않은 시료의 경우 유기물과 반응하여 Pt의 피크가 넓게 나타나나 열처리 후에는 유기물이 분해되어 Pt의 고유한 피크를 관찰할 수 있었다. 따라서 전기전도도의 변화는 유기물의 분해를 통하여 순수한 Pt로 변해가면서 감소하는 것으로 생각되어 지며 결정성 또한 전기전도도 변화에 중요한 역할을 함을 알 수 있었다. 기존의 방법을 이용하여 Pt를 증착할 경우 기판과 쉽게 박리 되는 현상이 관찰되었으나 본 방법을 이용하여 증착된 Pt 박막의 경우 열처리 후에는 기판과의 접착력이 기존의 방법보다 뛰어나 박리되는 현상이 관찰되지 않았다.$ 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.박막 형성 메카니즘에 큰 영향을 미침을 알 수 있었다. 또한 은의 전기화학적 다층박막 성장은 MSM (monolayer-simultaneous-multilayer) 메카니즘을 따름을 확인하였다. 마지막으로 구조 및 양이 규칙적으로 조절되는 전극의 응용가능성이 간단히 논의될 것이다.l 성장을 하였다는 것을 알 수 있었다. 결정성