• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.41-44
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• 2003

As the device feature size is reduced to the deep sub-micron regime, the chemical mechanical polishing (CMP) technology is widely recognized as the most promising method to achieve the global planarization of the multilevel interconnection for ULSI applications. However, cost of ownership (COO) and cost of consumables (COC) were relatively increased because of expensive slurry. In this paper, the effects of different slurry composition on the oxide CMP characteristics were investigated to obtain the higher removal rate and lower non-uniformity. We prepared the various kinds of slurry. In order to save the costs of slurry, the original slurry was diluted by de-ionized water (DIW). And then, alunima abrasives were added in the diluted slurry in order to promote the mechanical force of diluted slurry.

• Journal of the Korean Vacuum Society
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• v.7 no.2
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• pp.88-93
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• 1998

The fabrication process and emission characteristics of gated silicon field emitter arrays(FEAs) using chemical-mechanical-polishing (CMP) method are described. Novel fabrication techniques consisting of two-step dry etching with oxidation of silicon and CMP processes were developed for the formation of sharp tips and clear-cut edged gate electrodes, respectively. The gate height and aperture could be easily controlled by varying the polishing time and pressure in the CMP process. We obtained silicon FEAs having self-aligned and clear-cut edged gate electrode opening by eliminating the dishing problem during the CMP process with an oxide mask layer. The tip height of the finally fabricated FEAs was about 1.1 $\mu$m and the end radius of the tips was smaller than 100 $\AA$. The emission current meaured from the fabricated 2809 tips array was about 31 $\mu$A at a gate voltage of 80 V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.358-363
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• 2010

The polishing pad is important element for polishing characteristic such as material removal rate(MRR) and within wafer non-uniformity(WIWNU) in the chemical mechanical planarization(CMP). The result of the viscoelasticity measurement shows that 1st elastic modulus is increased and 2nd elastic modulus is decreased when the top pad is thickened. The finite element analysis(FEA) was conducted to predict characteristic of polishing behavior according to the pad thickness. The result of polishing experiment was similar with the FEA, and it shows that the 1st elastic modulus affects instantaneous deformation of pad related to MRR. And the 2nd elastic modulus has an effect on WIWNU due to the viscoelasticity deformation of pad.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.521-526
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• 2005

Within wafer non-uniformity(WIWNU) improves as the stiffness of pad decrease. We designed the pad groove to study of pad stiffness on WIWNU in Chemical mechanical polishing(CMP) and measured the pad stiffness according to groove width. The groove influences effective pad stiffness although original mechanical properties of pad are unchanged by grooving. Also, it affects the flow of slurry that has an effect on the lubrication regime and polishing results. An Increase of the apparent contact area of pad by groove width results in decrease of effective pad stiffness. WIWNU and profile of removal tate improved as effective pad stiffness decreased. Because grooving the pad reduce its effective stiffness and it makes slurry distribution to be uniform. Futhermore, it ensures that pad conforms to wafer-scale flatness variability. By grooving the top pad, it is possible to reduce its stiffness and hence reduce WIWNU and edge effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.145-148
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• 2003

Recently, the recycle of CMP (chemical mechanical polishing) slurries have been positively considered in order to reduce the high COO (cost of ownership) and COC (cost of consumables) in CMP process. Among the composition of slurries (buffer solution, bulk solution, abrasive particle, oxidizer, inhibitor, suspension, antifoaming agent, dispersion agent), the abrasive particles are one of the most important components. Especially, the abrasive particles of slurry are needed in order to achieve a good removal rate. However, the cost of abrasives, is still very high. In this paper, we have collected the silica abrasive powders by filtering after subsequent CMP process for the purpose of abrasive particle recycling. And then, we have studied the possibility of recycle of reused silica abrasive through the analysis of particle size and hardness. Also, we annealed the collected abrasive powders to promote the mechanical strength of reduced abrasion force. Finally, we compared the CMP characteristics between self-developed KOH-based silica abrasive slurry and original slury, As our experimental results, we obtained the comparable removal rate and good planarity with commercial products. Consequently, we can expect the saving of high cost slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.527-527
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• 2007

CMP가 1980년 IBM에 의해 반도체 웨이퍼의 표면 연마를 위해 적용된 후, 많은 연구 개발의 노력으로 반도체 집적회로의 제조 공정에서 필수 핵심기술이 되었으나, 소모자재(연마패드, 탄성지지대, 슬러리, 패드 컨디셔너)의 비용이 CMP 공정 비용의 70% 이상을 차지하는 등 제조단가가 높다는 단점을 극복할 수가 없었다. 특히, 고가의 슬러리가 차지하는 비중이 40% 이상을 넘고 있어, 슬러리 원액의 소모량을 줄이기 위한 연구들이 현재 활발히 연구 중이다. 슬러리의 변수로는 연마입자의 종류 및 특성, 용액의 pH, 연마입자의 슬러리내 안정성 등이 있다. 슬러리내 연마입자는 연마량과 균일도 측면에서 밀접한 관계를 가지고 있다. 또한, 연마제의 영향에 따라 연마율의 차이 즉, CMP 특성의 변화를 보이고 있기 때문에 투입량 또한 최적화가 필요하다. 본 연구에서는 새로운 연마제의 특성을 알아보기 위해 탈이온수(de-ionized water; DIW)에 $CeO_2,\;MnO_2,\;ZrO_2$ 등을 첨가한 후 분산시간에 따른 연마 특성과 atomic force microscopy (AFM)분석을 통해 표면 거칠기를 비교 분석하였다. 그리고, 세 가지 종류의 연마제를 각각 1wt%, 3wt%, 5wt% 첨가하여 산화막에 대한 CMP 특성을 알아본 후, scanning electron microscopy (SEM) 측정과 입도 분석을 통해 그 가능성을 알아보았다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.4
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• pp.303-308
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• 2005

In this paper, the effects of oxidants on tungsten chemical mechanical polishing (CMP) process were investigated using three different oxidizers such as Fe(NO₃)₃, KIO₃ and H₂O₂. Moreover, the interaction between the tungsten film and the oxidizer was discussed by potentiodynamic polarization measurement with three different oxidizers, in order to compare the effects of W-CMP and electrochemical characteristics on the tungsten film as a function of oxidizer. As an experimental result, the tungsten removal rate reached a maximum at 5 wt％ Fe(NO₃)₃concentration, and when 5 wt％ H₂O₂was added in the slurry, the removal rate of W increased. Also, the microstructures of surface layer by atomic force microscopy(AFM) image were greatly influenced by the slurry chemical composition of oxidizers. It was shown that the surface roughness and removal rate of the polished surface were improved in Fe(NO₃)₃than KIO₃. The electrochemical results indicate that the corrosion current density of the 5 wt％ H₂O₂ and 5 wt％ H₂O/sub 2+/＋ 5 wt％ Fe(NO₃)₃was higher than the other oxidizers. Therefore, we conclude that the W-CMP characteristics are strongly dependent on the kinds of oxidizers and the amounts of oxidizer additive.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.118-118
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• 2008

The oxide CMP has been applied to interlayer dielectric(ILD) and shallow trench isolation (STI) in chip fabrication. Recently the slurry used in oxide CMP being changed from silica slurry to ceria (cerium dioxide) slurry particularly in STI CMP, because the material selectivity of ceria slurry is better than material selectivity of silica slurry. Moreover, the ceria slurry has good a planarization efficiency, compared with silica slurry. However ceria abrasives make a material removal rate too high at the region of wafer center. Then we focuses on why profile of material removal rate is convex. The material removal rate sharply increased to 3216 $\AA$/min by $4^{th}$ run without conditioning. After $4^{th}$ run, material removal rate converged. Furthermore, profile became more convex during 12 run. And average material removal rate decreased when conditioning process is added to end of CMP process. This is due to polishing mechanism of ceria. Then the ceria abrasive remains at the pad, in particular remains more at wafer center contacted region of pad. The field emission scanning electron microscopy (FE-SEM) images showed that the pad sample in the wafer center region has a more ceria abrasive than in wafer outer region. The energy dispersive X-ray spectrometer (EDX) verified the result that ceria abrasive is deposited and more at the region of wafer center. Therefore, this result may be expected as ceria abrasives on pad surface causing the convex profile of material removal rate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.539-539
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• 2008

본 논문에서는 투명전도박막의 균일한 표면특성을 확보하기 위해 광역평탄화 공정을 적용하여 투명전도 박막의 표면 거칠기를 연구하였으며 슬러리의 종류에 따른 박막의 연마특성을 연구하였다. 본 실험에서 사용된 ITO 박막은 RF Sputtering에 의해 제작되었고 하부 기판은 석영 Glass가 사용되었다. 광역평탄화를 위한 CMP 공정은 고분자 물질계열의 패드위에 슬러리입자를 공급하고 웨이퍼 캐리어에 하중을 가하며 웨이퍼의 표면을 연마하는 방법으로 가공물을 탄성패드에 누르면서 상대 운동시켜 가공물과 친화력이 우수한 부식액으로 화학적 제거를 함과 동시에 초미립자로 기계적 제거를 하는 것이다. ITO 박막의 평탄화를 위한 공정조건은 Polisher pressure 300 g/$cm^2$, 슬러리 유속 80 ml/min, 플레이튼속도 60 rpm으로 하였다. 위의 조건에 따라 공정을 진행 후 연마특성을 측정하였으며 이때 사용된 슬러리는 산화막에 사용되는 실리카슬러리와 금속연마용 슬러리인 EPL을 사용하였다. 연마율은 실리카 슬러리가 EPL슬러리에 비해 높음을 확인 하였다. CMP 공정에 의해 평탄화를 수행 할 경우 실리카슬러리와 EPL슬러리 모두 CMP전에 비해 돌출된 힐록들이 감소되었음을 알 수 있었다. 비균일도 특성은 모든 슬러리가 양호한 특성을 나타내었다. 평탄화된 박막의 표면과 거칠기 특성은 AFM(XE-200, PSIA Company) 을 이용하여 분석을 하였다.

• 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.