• Transactions on Electrical and Electronic Materials
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• 제6권4호
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• pp.164-168
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• 2005

Effects of high-temperature slurry were investigated on the chemical mechanical polishing (CMP) performance of tetra-ethyl ortho-silicate (TEOS) film with silica and ceria slurries by the surface analysis of X-ray photoelectron spectroscopy (XPS). The pH showed a slight tendency to decrease with increasing slurry temperature, which means that the hydroxyl $(OH^-)$ groups increased in slurry as the slurry temperature increased and then they diffused into the TEOS film. The surface of TEOS film became hydro-carbonated by the diffused hydroxyl groups. The hydro-carbonated surface of TEOS film could be removed more easily. Consequently, the removal rate of TEOS film improved dramatically with increasing slurry temperature.

• 한국기계가공학회지
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• 제11권1호
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• pp.7-12
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• 2012

Chemical mechanical polishing(CMP) technology is faced with the challenge of processing new electronic materials. This paper focuses on the balance between chemical and mechanical reactions in the CMP process that is required to cope with a variety of electronic materials. The material properties were classified into the following categories: easy to abrade(ETA), difficult to abrade(DTA), easy to react(ETR) and difficult to react(DTR). The chemical and mechanical balance for the representative ETA-ETR, DTA-ETR, ETA-DTR and DTA-DTR materials was considered for defect-free surfaces. This paper suggests the suitable polishing methods and examples for each electronic material.

• 한국정밀공학회지
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• 제22권2호
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• pp.46-52
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• 2005

The sapphire wafer was polished by the implementation of the surface machining technology based on nano-tribology, The removal process has been performed by grinding, lapping and chemical-mechanical polishing. For the chemical mechanical polishing process, the chemical reaction between the slurry and sapphire wafer was investigated in terms of the change of Zeta-potential between two materials. The Zeta-potential was -4.98 mV without the slurry in deionized water and was -37.05 mV for the slurry solution. By including the slurry into the deionized water the Zeta-potential -29.73 mV, indicating that the surface atoms of sapphire become more repulsive to be easy to separate. The average roughness of the polished surface of sapphire wafer was ranged to 1∼4$\AA$.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권4호
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• pp.318-328
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• 2011

Stage-level reconfigurable chip multiprocessor (CMP) aims to achieve highly reliable and fault tolerant computing by using interwoven pipeline stages and on-chip interconnect for communicating with each other. The existing crossbar-switch based stage-level reconfigurable CMPs offer high reliability at the cost of significant area/power overheads. These overheads make realizing large CMPs prohibitive due to the area and power consumed by heavy interconnection networks. On other hand, area/power-efficient architectures offer less reliability and inefficient stage-level resource utilization. In this paper, I propose a hierarchical multiplexing interconnection structure in lieu of crossbar interconnect to design area/power-efficient stage-level reconfigurable CMP. The proposed approach is able to keep the reliability offered by the crossbar-switch while reducing the area and power overheads. Experimental results show that the proposed approach reduces area by up to 21% and power by up to 32% when compared with the crossbar-switch based interconnection network.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.528-528
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• 2007

Cu CMP widely has been using for the formation of multilevel metal interconnects by the Cu damascene process. And lower dielectric constant materials are required for the below 45nm technology node. As the dielectric constant of dielectric materials are smaller, the strength of dielectric materials become weaker. Therefore these materials are easily damaged by high down pressure during conventional CMP. Also, technical problems such as surface scratches, delamination, dishing and erosion are also occurred. In order to overcome these problems in CMP, the ECMP (electro-chemical mechanical planarization) has been introduced. In this process, abrasive free electrolyte, soft pad and low down force were used. The electrolyte is one of important factor to solve these problems. Also, additives are required to improve the removal rate, uniformity, surface roughness, defects, and so on. In this study, KOH and $NaNO_3$ based electrolytes were used for Cu ECMP and the electrochemical behavior was evaluated by the potentiostat. Also, the Cu surface was observed by SEM as a function of applied voltage and chemical concentration.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.82-82
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• 2007

The chemical mechanical polishing (CMP) process has been widely used to obtain global planarization of multilevel interconnection process for ultra large scale. integrated circuit applications. Especially, the application of copper CMP has become an integral part of several semiconductor device and materials manufacturers. However, the low-k materials at 65nm and below device structures because of fragile property, requires low down-pressure mechanical polishing for maintaining the structural integrity of under layer during their fabrication. In this paper, we studied electrochemical mechanical polishing (ECMP) as a new planarization technology that uses electrolyte chemistry instead of abrasive slurry for copper CMP process. The current-voltage (I-V) curves were employed we investigated that how this chemical affect the process of voltage induced material removal in ECMP of Copper. This work was supported by grant No. (R01-2006-000-11275-0) from the Basic Research Program of the Korea Science.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.78-78
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• 2007

In semiconductor devices, Cu has been used for the formation of multilevel metal interconnects by the damascene technique. Also lower dielectric constant materials is needed for the below 65 nm technology node. However, the low-k materials has porous structure and they can be easily damaged by high down pressure during conventional CMP. Also, Cu surface are vulnerable to have surface scratches by abrasive particles in CMP slurry. In order to overcome these technical difficulties in CMP, electro-chemical mechanical planarization (ECMP) has been introduced. ECMP uses abrasive free electrolyte, soft pad and low down-force. Especially, electrolyte is an important process factor in ECMP. The purpose of this study was to characterize KOH and $KNO_3$ based electrolytes on electro-chemical mechanical. planarization. Also, the effect of additives such as an organic acid and oxidizer on ECMP behavior was investigated. The removal rate and static etch rate were measured to evaluate the effect of electro chemical reaction.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.165-165
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• 2007

투명전도박막은 ITO, $SnO_2$, ZnO, 등이 있으나 $SnO_2$는 자외선 영역까지 투과시키는 우수한 광학적 특성을 나타내지만, 상당히 큰 전기저항으로 인해 현재는 현재 ITO가 널리 이용되고 있다. ITO(Indium Tin Oxide)박막은 자외선 영역에서 반사율이 높으며 가시광선영역에서는 80%이상의 뛰어난 투과율을 가지고 있다. 또한 낮은 전기저항과 넓은 광학적 밴드갭 때문에 가장 유용한 투과전도성 재료 중에 하나이다. 이러한 특성 때문에 여러 가지 문자 표시소자의 투명전극, 태양전지의 창재료, 정전차폐를 위한 반도체 포장재료, 열반사막, 면발열체, 광전변환 소자에 응용되고 있다. 일반적으로 박막의 제작에는 저항가열법과 전자선가열법, 스퍼터링법의 물리적 증착과 화학적 증착으로 나뉜다. 본 논문에서는 증착온도를 달리 하여 RF-sputtering에 의해 ITO박막을 증착한 후 온도증가에 따른 박막의 특성을 연구하였으며 또한 광역평탄화를 위한 CMP공정을 적용하여 증착온도가 연마에 미치는 영향을 연구하였다. 본 실험에서 사용된 ITO박막은 $2{\times}2Cm$의 Corning glass위에 증착되었으며 타겟은 $In_2O_3$와 $SnO_2$가 9:1로 혼합된 Purity 99.99%이상의 직경 2 inch인 ITO타겟을 사용하였다. 박막 증착시 기판온도는 상온에M $200^{\circ}C$까지 변화시켰으며 RF power는 100W로 일정하게 하였으며 증착압력은 $8{\times}10^{-2}$Torr이였다. CMP공정조건은 헤드속도 60rpm, 플레이튼 속도 60rpm, 슬러리 주입 유량 60mml/min, 압력 $300g/cm^2$이였다. 전기적 특성은 four point probe를 이용하여 측정하였으며 광학적 특성은 UV-Visible Spectrometer를 이용하여 200~900nm의 파장범위에서 광투과도를 측정하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.136-139
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• 2003

Copper has attractive properties as a multi-level interconnection material due to lower resistivity and higher electromigration resistance as compared with Alumina and its alloy with Copper(0.5%). Among a variety of agents in Copper CMP slurry, $H_2O_2$ has commonly been used as the oxidizer However. $H_2O_2$ is so unstable that it requires stabilization to use as oxidizer Hence, stabilization of $H_2O_2$ is a vital process to get better yield in practical CMP process. In this article the stability of Hydrogen Peroxide as oxidizer of Copper CMP slurry has been investigated. When alumina abrasive was used, $\gamma$-particle Alumina C had a better stability than $\alpha$-particle abrasive. As adding KOH as pH buffering agent, $H_2O_2$ stability in slurry decreased. Urea hydrogen peroxide was used as oxidizer, an enhanced stability was gotten. When $H_3PO_4$ as $H_2O_2$ stabilizer was added, the decrease of $H_2O_2$ concentration in slurry became slower. Even though adding $H_2O_2$ in slurry after bead milling lead to better stability than in advance of bead milling, it had a lower dispersibility.

• Earthquakes and Structures
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• 제9권2호
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• pp.353-373
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• 2015

In this paper, the effects of different types of irregularity along the height on the seismic responses of moment resisting frames are investigated using nonlinear dynamic analysis. Furthermore, the applicability of consecutive modal pushover (CMP) procedure for computing the seismic demands of vertically irregular frames is studied and the advantages and limitations of the procedure are elaborated. For this purpose, a special moment resisting steel frame of 10-storey height was selected as reference regular frame for which the effect of higher modes is important. Forty vertically irregular frames with stiffness, strength, combined-stiffness-and-strength and mass irregularities are created by applying two modification factors (MF=2 and 4) in four different locations along the height of the reference frame. Seismic demands of irregular frames are computed by using the nonlinear response history analysis (NL-RHA) and CMP procedure. Modal pushover analysis (MPA) method is also carried out for the sake of comparison. The effect of different types of irregularity along the height on the seismic demands of vertically irregular frames is investigated by studying the results obtained from the NL-RHA. To demonstrate the accuracy of the enhanced pushover analysis methods, the results derived from the CMP and MPA are compared with those obtained by benchmark solution, i.e., NL-RHA. The results show that the CMP and MPA methods can accurately compute the seismic demands of vertically irregular buildings. The methods may be, however, less accurate especially in estimating plastic hinge rotations for weak or weak-and-soft top and middle storeys of vertically irregular frames.