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Zhang Z.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang Z.,Shanghai Xinanna Electronic Technology Co. | Zhang Z.,University of Chinese Academy of Sciences | Liu W.,CAS Shanghai Institute of Microsystem and Information Technology | And 3 more authors.
Microelectronic Engineering | Year: 2010

Effect of abrasive particle concentration on material removal rate (MRR), MRR per particle and the surface quality in the preliminary chemical mechanical polishing (CMP) of rough glass substrate was investigated. Experimental results showed that the MRR increases linearly with the increase of abrasive concentration and reaches to the maximum when the abrasive concentration is 20 wt.%, and then tends to be stable. When the abrasive concentration increases from 2 to 5 wt.%, the MRR per particle increases greatly and reaches a peak. Then the MRR per particle decreases almost linearly with the increase of the abrasive concentration. The root mean squares (RMS) roughness almost decreases with increasing particle concentration. In addition, in situ coefficient of friction (COF) was also conducted during the polishing process and the zeta potentials of abrasive particles in slurry with different solid concentration were also characterized. Results show that COF value is not related to zeta potential but be sensitive to glass surface conditions in terms of rough peaks in preliminary polishing of glass substrate. © 2010 Elsevier Ltd. All rights reserved.


Zhang L.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang L.,Shanghai Xinanna Electronic Technology Co. | Zhang L.,University of Chinese Academy of Sciences | Liu W.-L.,CAS Shanghai Institute of Microsystem and Information Technology | And 3 more authors.
Gongneng Cailiao yu Qijian Xuebao/Journal of Functional Materials and Devices | Year: 2012

A novel method was developed to prepare monodisperse ultrafine silica using ammonia as a catalyst by means of hydrolysis of tetraethoxysilane (TEOS). Polyvinylpyrrolidone (PVP) can effectively reduce the silica particles size. It was found that the size of monodisperse silica particles tends to decrease with increase of the PVP concentration. By using the optimum process parameters, monodisperse silica nanoparticles with diameter 11 nm were prepared. Furthermore, these monodisperse silica spheres can be successfully used as seeds in the regrowth procedure in the same reaction media. The size of the particles can be precisely controlled by addition various TEOS concentration.


Yu L.,CAS Shanghai Institute of Microsystem and Information Technology | Yu L.,Shanghai Xinanna Electronic Technology Co. | Yu L.,University of Chinese Academy of Sciences | Liu W.-L.,CAS Shanghai Institute of Microsystem and Information Technology | And 5 more authors.
Chinese Chemical Letters | Year: 2015

In this paper, a facile synthesis of 100. nm commercial colloid silica coated with nano-ceria core-shell composite particles by the precipitation method using ammonium cerium nitrate and urea as a precipitator with polyvinylpyrrolidone (PVP) as an assistant was briefly introduced. The results showed that the colloid silica was surrounded by nano-ceria uniformly forming the core-shell composite particles. The synthesis process was further discussed and optimized. It was found that the type and quantity of surfactant played a key role in the process. PVP connected the surface of colloid silica and that of the ceria precursor. © 2015 Wei-Li Liu.


Wang H.,CAS Shanghai Institute of Microsystem and Information Technology | Wang H.,Shanghai Xinanna Electronic Technology Co. | Wang H.,University of Chinese Academy of Sciences | Song Z.,CAS Shanghai Institute of Microsystem and Information Technology | And 5 more authors.
Microelectronic Engineering | Year: 2011

The effect of hydrogen peroxide (H2O2) concentration in alkaline slurry on the surface micro-roughness of final polished silicon wafer was investigated. The root mean square roughness (RMS) reached minimum with H2O2 when the concentration is 0.05 wt%. Meanwhile, the contact angle of the polished surface was decreased to 21°. This decrease was attributed to enhanced chemical reaction in the CMP process. Electrochemical impedance was measured to explore the variation with addition of H2O2 in the reaction process of silicon erosion. Based on the measurements, a mechanism was suggested to explain the phenomenon in combine with the coefficient of friction force in the chemical mechanical polishing (CMP) process. © 2010 Elsevier B.V. All rights reserved.


Zhang Z.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang Z.,Shanghai Xinanna Electronic Technology Co. | Zhang Z.,University of Chinese Academy of Sciences | Liu W.,CAS Shanghai Institute of Microsystem and Information Technology | And 3 more authors.
Applied Optics | Year: 2010

This study explores the effect of particle size and surfactant on the chemical mechanical polishing (CMP) of glass using colloidal silica-based slurry. It was found that the material removal rate strongly depends on the particle size and the types of surfactants and that the rms roughness was independent of particle size and correlated to surfactants. On the basis of polishing results, it was concluded that the main polishing mechanism was changed from indentation mechanism to surface-area mechanism, with the variation of particle size. In addition, the molecular structure, charge type, and lubricating effect of the surfactants play an important role in the dispersion of abrasive particles and in the CMP performance. © 2010 Optical Society of America.


Zhang L.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang L.,Shanghai Xinanna Electronic Technology Co. | Zhang L.,University of Chinese Academy of Sciences | Wang H.,CAS Shanghai Institute of Microsystem and Information Technology | And 11 more authors.
Gongneng Cailiao yu Qijian Xuebao/Journal of Functional Materials and Devices | Year: 2011

Abrasive is an important component of the chemical mechanical polishing(CMP) system. It is an important factor that determines the planarization in CMP. Novel silica coated polystyrene(PS) core-shell composite abrasives were prepared via a two-step process. The composite abrasives were characterized by Scanning Electron Microscope(SEM), Transmission Electron Microscope(TEM) and Energy Dispersive X-ray Analysis(EDX). The results indicate that composite abrasive has a core-shell structure and smooth surface. The chemical mechanical polishing(CMP)performances of the composite abrasive and colloidal silica on blanket copper wafers were investigated. The copper surfaces were characterized by Atomic force microscopy(AFM). The results show that the average roughness of the polished copper is 0.58 nm for composite abrasive and the removal rate is 40nm/min. The average roughness of the polished copper is 1.95 nm for colloidal silica and the removal rate is 37nm/min.


Zhang Z.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang Z.,Shanghai Xinanna Electronic Technology Co. | Zhang Z.,University of Chinese Academy of Sciences | Liu W.,CAS Shanghai Institute of Microsystem and Information Technology | And 5 more authors.
Applied Surface Science | Year: 2010

Nano-sized ceria particles were coated on the silica surface by the precipitation method using ammonium cerium nitrate and urea as precipitant with poly(vinylpyrrolidone) (PVP) as assistant. The structures and compositions of ceria-coated silica particles were characterized using X-ray diffraction (XRD), field-emission scanning microscopy (FE-SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements. The results show that nano-size ceria particles were coated uniformly around the surface of silica particles when PVP was used as assistant during coating process, while without PVP, the ceria particles were grown sparsely on the silica particle surface and many ceria particles grow up through independent nucleation in the solution. Then, the chemical mechanical polishing (CMP) behaviors of the as-prepared ceria-coated silica particles on glass substrate were investigated. The CMP test results suggest that the as-prepared ceria-coated silica particles exhibit higher removal rate than pure silica particles without deteriorating the surface quality. In addition, online coefficient of friction (COF) was conducted during the polishing process. The COF data indicate that the COF values of ceria-coated silica particles are larger than those of pure silica particles due to their surface properties. © 2010 Elsevier B.V. All rights reserved.


Zhang Z.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang Z.,Shanghai Xinanna Electronic Technology Co. | Zhang Z.,University of Chinese Academy of Sciences | Yu L.,CAS Shanghai Institute of Microsystem and Information Technology | And 5 more authors.
Applied Surface Science | Year: 2010

To improve their chemical mechanical polishing (CMP) performance, ceria nanoparticles were surface modified with γ-aminopropyltriethoxysilane (APS) through silanization reaction with their surface hydroxyl group. The compositions, structures and dispersibility of the modified ceria particles were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), laser particle size analyzer, zeta potential measurement and stability test, respectively. The results indicated that APS had been successfully grafted onto the surface of ceria nanoparticles, which led to the modified ceria nanoparticles with better dispersibility and stability than unmodified ceria particles in aqueous fluids. Then, CMP performance of the modified ceria nanoparticles on glass substrate was investigated. Experimental results showed that the modified ceria particles exhibited lower material removal rate (MRR) but much better surface quality than unmodified ceria particles, which may be explained by the hardness reduction of ceria particles, the enhancement of lubrication of the particles and substrate surfaces, and the elimination of the agglomeration among the ceria particles. © 2010 Elsevier B.V. All rights reserved.


Zhang L.,CAS Shanghai Institute of Microsystem and Information Technology | Zhang L.,Shanghai Xinanna Electronic Technology Co. | Zhang L.,University of Chinese Academy of Sciences | Wang H.,CAS Shanghai Institute of Microsystem and Information Technology | And 11 more authors.
Applied Surface Science | Year: 2011

Monodisperse silica-coated polystyrene (PS) nano-composite abrasives with controllable size were prepared via a two-step process. Monodisperse positively charged PS colloids were synthesized via polymerization of styrene by using a cationic initiator. In the subsequent coating process, silica formed shell on the surfaces of core PS particles via the ammonia-catalyzed hydrolysis and condensation of tetraethoxysilane. Neither centrifugation/water wash/redispersion cycle process nor surface modification or addition surfactant was needed in the whole process. The morphology of the abrasives was characterized by scanning electron microscope. Transmission electron microscope and energy dispersive X-ray analysis results indicated that silica layer was successfully coated onto the surfaces of PS particles. Composite abrasive has a core-shell structure and smooth surface. The chemical mechanical polishing performances of the composite abrasive and conventional colloidal silica abrasive on blanket copper wafers were investigated. The root mean square roughness decreases from 4.27 nm to 0.56 nm using composite abrasive. The PS/SiO2 core-shell composite abrasives exhibited little higher material removal rate than silica abrasives. © 2011 Elsevier B.V. All rights reserved.


Zefang Z.,Chinese Academy of Sciences | Zefang Z.,Shanghai Xinanna Electronic Technology Co. | Zefang Z.,University of Chinese Academy of Sciences | Weili L.,Chinese Academy of Sciences | And 3 more authors.
Journal of Semiconductors | Year: 2010

The effect of the ammonium molybdate concentration on the material removal rate (MRR) and surface quality in the preliminary chemical mechanical polishing (CMP) of a rough glass substrate was investigated using a silica-based slurry. Experimental results reveal that the ammonium molybdate concentration has a strong influence on the CMP behaviors of glass substrates. When the ammonium molybdate was added to the baseline slurry, polishing rates increased, and then decreased with a transition at 2 wt.%, and the root mean square (RMS) roughness decreased with increasing ammonium molybdate concentration up to 2 wt.%, after which it increased linearly up to 4 wt.%. The improvement in MRR and RMS roughness may be attributed to the complexation of hydrolysis products of the glass substrate with the ammonium molybdate so as to prevent their redeposition onto the substrate surface. It was found that there exists an optimal ammonium molybdate concentration at 2 wt.% for obtaining the highest MRR and the lowest RMS roughness within a particular polishing time. © 2010 Chinese Institute of Electronics.

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