Oxide Chemical Mechanical Polishing Research Articles

Development of Ceria Slurry for Enhanced Chemical Mechanical Polishing (CMP) Performance

As the semiconductor device is shrinking and gets complicated, the chemical mechanical polishing (CMP) process has become important. Various types of abrasive particles are used as CMP slurry, and among them, ceria slurry is in the spotlight due to its high material removal rate (MRR) and selectivity on oxide CMP process. It is known that the ceria abrasives form Ce-O-Si chemical bonds with oxide film, which makes it possible to achieve a high CMP performance.To further advance the performance of ceria slurry, we conducted a series of researches on ceria. A study was conducted on scanning mobility particle sizer (SMPS) measurement to accurately evaluate particle size distribution along with the basic polishing mechanism of monodisperse ceria nanoparticles. In addition, an optimization study was conducted considering the CMP performance according to the abrasive concentration of ceria slurry and the influence of ceria nanoparticles remaining on the wafer surface before the post-CMP cleaning process. Furthermore, research on synthesis method and surface modification of ceria was also conducted to improve the polishing performance. Ce3+ ions on the surface of ceria form Ce-O-Si chemical bond with the silicon dioxide film. Therefore, an important key point is to increase the concentration of Ce3+ ions to improve polishing performance. To achieve high Ce3+ ion concentration, ceria nanoparticles were synthesized through a hydrothermal method, and this performance was improved through lanthanide doping. On the other hand, methods to enhance Ce3+ ion concentration by inducing a reduction reaction on the surface of ceria nanoparticles were also proposed. First, the polishing performance was improved by adding trace metals (FeCl2, CrCl2) to induce a reduction reaction of ceria nanoparticles. Next, the reduction reaction of ceria was induced by applying an eco-friendly method which did not add chemical agents. Ultraviolet (UV) irradiation and hydrogen-gas reduction methods showed sufficient reduction reaction to improve the polishing performance of ceria slurry, and maintained physical properties without causing CMP defects such as poor surface roughness and micro-scratches.As with previous polishing studies, post-CMP cleaning is also important to decease defects. While ceria nanoparticles exhibit great polishing performance for silicon dioxide due to their ability to form chemical bonds, however, they also have the disadvantage of being difficult to remove during the post-CMP cleaning process. To efficiently remove ceria nanoparticles from the wafer surface during the post-CMP cleaning process, various methods have been studied. First, the buff cleaning process was studied in which a deionized water-based cleaning solution is injected instead of slurry after the CMP process. Since the buff cleaning process must simultaneously minimize damage of wafer surface and maximize cleaning performance, optimization research on the properties of the physical factors and cleaning solution is important. For an environmentally friendly cleaning method, we proposed controlling the viscosity of deionized water or using gas-dissolved water. It has been proven that physical factors of cleaning solutions (viscosity, micro bubbles, etc.) can be effective in removing ceria nanoparticles. Especially, hydrogen gas in gas-dissolved water induced a reduction reaction, breaking Ce-O-Si bonds and improving the cleaning performance. Limited to the bulk ceria CMP process, we also studied the improvement of cleaning performance of remained ceria nanoparticles using the tangential flow filtration (TFF) method before CMP process. We focused that small contaminant particles are difficult to remove during the cleaning process, and through the TFF method, small abrasive particles in the slurry are filtered in advance while maintaining the polishing performance.

Investigation of thermal effects in bulk oxide chemical mechanical polishing

Bulk oxide polishing occupies a substantial portion of time to achieve surface planarization in semiconductor manufacturing. Recently, thermal management has emerged as a critical issue in the polishing process. Fundamental research on thermal effects in oxide film polishing is essential for optimizing both the thermal management system and the polishing process itself. Experiments indicate that friction force, significantly influenced by wafer and retainer ring pressures as well as slurry species, plays a major role in determining polishing temperature, more so than slurry flow rate. An important finding is the temperature-dependent behavior of slurry particles, which generally reduce in size and concentrate more at higher temperatures, with aggregation starting at around 80 °C. High-temperature slurry deteriorated pad properties but enhance oxide film surface hydrolyzation. During a 60-s polishing process, the slurry temperature exhibited the maximum removal rate at 60 °C for fumed silica polishing, while for calcined ceria, the highest removal rate was observed at 20 °C. Pad B at ambient temperature, having similar hardness to Pad A at 60 °C, reduced the oxide film removal rate by 31.82 % for fumed silica and 40.94 % for calcined ceria. This indicates that pad hardness has a more pronounced effect on polishing with calcined ceria slurry.

Real-time prediction of material removal rate for advanced process control of chemical mechanical polishing

Polishing torque holds significance in monitoring the chemical mechanical polishing (CMP) process due to its close correlation with material removal. This study introduces a new model-based technique for estimating the material removal rate (MRR) using in-process data from CMP machines. The proposed method employs either the sequential least squares method or Kalman filter for real-time state estimation. Real-time estimation of MRR enables material removal control without relying on conventional endpoint detection (EDP) technologies. The accuracy of the proposed approach is validated through oxide CMP experiments, demonstrating precise estimation of the center-slowed MRR profile towards the end of the pad life.

Improvement of oxide chemical mechanical polishing performance by increasing Ce3+/Ce4+ ratio in ceria slurry via hydrogen reduction

Ceria-based abrasive is widely used in the oxide chemical mechanical polishing (CMP) process due to its high polishing performance. Ce3+ ions on the surface of ceria form a Ce–O–Si chemical bond with surface of the SiO2 wafer, significantly affecting the material removal rate (MRR). In this study, the ceria surface was reduced by contact with hydrogen gas in a high temperature isothermal environment. Hydrogen gas forms surface hydroxyls on the ceria. Then, the generated hydroxyls form H2O and oxygen vacancies occur through the desorption of the H2O. The color of ceria changed to blue due to a change of the crystal structure by the reduction reaction. The reducing ability of hydrogen gas increased as the reduction temperature increased and the Ce3+ ion concentration increased by 12.7% under isothermal conditions at 1000 °C. The MRR of reduced ceria was improved by up to 37.7% compared to the original ceria.

Simulation and Experimental Investigation of the Radial Groove Effect on Slurry Flow in Oxide Chemical Mechanical Polishing

Slurry flow on the pad surface and its effects on oxide chemical mechanical polishing (CMP) performance were investigated in simulations and experiments. A concentric groove pad and the same pad with radial grooves were used to quantitatively compare the slurry saturation time (SST), material removal rate (MRR), and non-uniformity (NU) in polishing. The monitored coefficient of friction (COF) and its slope were analyzed and used to determine SSTs of 25.52 s for the concentric groove pad and 16.06 s for a certain radial groove pad. These values were well correlated with the simulation prediction, with around 5% error. Both the laminar flow and turbulent flow were included in the sliding mesh model. The back mixing effect, which delays fresh slurry supply, was found in the pressure distribution of the wafer–pad interface.

Tangential flow filtration of ceria slurry: Application of a single-pass method to improve buff cleaning

Ceria slurries are used in the oxide chemical mechanical polishing (CMP) process due to their high polishing performance and selectivity characteristics. However, it takes great effort to remove small ceria particles that remain on the wafer surface during the post-CMP cleaning process. Therefore, we applied tangential flow filtration (TFF) systems, which can be used to separate small ceria particles before CMP process. In a previous study, we improved the post-CMP cleaning efficiency of the ceria slurry with a circulation-type TFF system. Herein, the correlations between the separation rate of ceria particles and parameters affecting the TFF system, such as membrane pore size, flow rate, and transmembrane pressure (TMP), were evaluated to improve buff cleaning efficiency. Finally, we also fabricated a single-pass TFF system to reduce the process time and loss of active ceria particles. With the single-pass TFF system, the basic properties and polishing performance of the ceria slurry did not change. In addition, the buff cleaning efficiency improved by up to 18.1%.

Development of Zr- and Gd-doped porous ceria (pCeO2) abrasives for achieving high-quality and high-efficiency oxide chemical mechanical polishing

Porous ceria (pCeO2), Zr-doped pCeO2 (pCeZrO2), and Gd-doped pCeO2 (pCeGdO2) abrasives for both surface quality and removal rate improvements were developed using a facile one-pot solvothermal approach. The resulting products were characterized via XRD, SEM, TEM, HRTEM, Raman spectroscopy, UV–visible spectroscopy, and N2 adsorption-desorption measurements. Raman spectra revealed that oxygen vacancies were the dominant defects in pCeO2 nanospheres. Zr- and Gd-doping treatments contributed to oxygen vacancy enrichment, thus leading to an increased content of trivalent cerium (Ce3+) formed on the pCeO2 surfaces. Oxide-CMP capability of pure pCeO2, pCeZrO2, and pCeGdO2 abrasives were compared in terms of surface morphology/roughness/defect, topographical variation, as well as material removal rate (MRR). Atomic force microscopy and interferometric microscopy investigations showed that both pCeO2, pCeZrO2, and pCeGdO2 abrasives achieved high-quality surfaces with ultra-low roughness (0.11–0.14 nm Ra, 0.13–0.17 nm RMS). As expected, the MRR was accelerated by 78.7% in alkaline slurries containing pCeGdO2 abrasives compared to the undoped pCeO2. The improved CMP performance might be attributed to the reduced modulus, the expend pore size, as well as the enriched Ce3+ and oxygen vacancy. Furthermore, the interfacial action and removal mechanism of the pCeO2 abrasives were discussed on the basis of their structure feature and surface chemistry.

Auxiliary mechanism of in-situ micro-nano bubbles in oxide chemical mechanical polishing

Silicon dioxide is the most important gate oxide dielectric material, and its surface planarization is an important factor in the continuous shrinking of the size of integrated circuits. Developing a novel chemical mechanical polishing auxiliary technique to achieve efficient polishing of oxide wafers is a significant challenge. In this study, a novel in-situ micro-nano bubbles auxiliary method, which used a nano-hydrophobic film to prepare a gas supersaturated slurry that can generate instant in-situ micro-nano bubbles during polishing, was developed for oxide wafers. Compared with conventional slurries, this auxiliary method increased the material removal rate by about 30% and ensured the low surface roughness of the wafer of 0.14 nm. The existence of micro-nano bubbles and the multi-size distribution and zeta potential of the micro-nano bubbles were measured by optical microscope and dynamic light-scattering methods. Then, to investigate the auxiliary mechanism of this in-situ micro-nano bubbles, different analytical methods, such as oxide thickness measurement system, scanning electron microscopy, Fourier transform infrared spectroscopy, and atomic force microscopy, were used to characterize the sample. The results indicated that during the polishing process, the micro-nano bubbles generated in situ have a good cleaning effect. In addition, the free radicals generated after in-situ micro-nano bubbles burst simultaneously modified the surfaces of the wafer and the pad. The improvement of the adsorption between the wafer and abrasives promoted the chemical reaction between them. After conditioning, the rougher and cleaner pad had a higher mechanical effect. Most importantly, this in-situ micro-nano bubbles auxiliary method has the potential to be applicable to all slurries.

Soft Chemical Mechanical Polishing Pad for Oxide CMP Applications

Chemical mechanical polishing (CMP) is widely accepted as the best planarization technique for fabricating nanoscale devices. A soft CMP pad that can enable higher oxide removal rates (RRs) and good planarity has been proposed for oxide CMP applications. In this study, three pads namely, Pad-1 (hard), Pad-2 (soft), and a commercial pad (hard) were used to polish blanket oxide, and STI patterned wafers. The Pad-2 demonstrated significantly higher RRs and better planarization than the hard pads. Post-polish pad texture analysis on Pad-2 showed a uniform surface asperity distribution. This is due to the novel method of pad manufacturing, which enables precise material placement and consistent pore construction.

Effects of Amino Acids on Silicon Oxide for High Silicon Oxide Removal Rate Ceria Slurry

Chemical mechanical polishing (CMP) is a process for flattening a wafer, and its importance is increasing as design rules are shrunk. There are Inter Level Dielectric (ILD), Shallow Trench isolation (STI), and 3D-NAND CMP processes for polishing the oxide surface in the CMP process. In the case of 3D-NAND CMP, a high removal rate (RR) slurry is required because a thick oxide film must be polished in a short time. Generally, ceria or silica slurries are used in oxide CMP. Ceria slurry shows high RR by Ce-O-Si bonding. The slurry includes additives for purpose of dispersion of abrasive, pH adjustment, change of wafer surface properties. Amino acids have various functional groups depending on the pH. Depending on the activity of the functional groups, the amino acid has various effects on the surface of the slurry or silicon oxide. Amino acids were used additive in slurry and some amino acids increased the removal rate. We investigated the effect of some amino acids on the silicon oxide wafers and ceria slurry. The effect of amino acids on the removal rate was analyzed by zeta potential, contact angle and X-ray photoelectron spectroscopy analysis. Our results indicate that some amino acid adsorb on oxide surface and increase the values of absolute zeta potential. Differences in zeta potential values between slurry and wafer surface make high removal rate. Figure 1

Model of Particle Contact Area for Friction in Oxide Chemical Mechanical Polishing

Friction from Chemical Mechanical Polishing (CMP) of integrated circuits can cause damage to surface and sub-surface layers. To understand potentially damaging CMP friction, a model is presented which separates the contributions of: 1) bare pad asperity to substrate junction contacts, 2) slurry nanoparticles in the pad asperity contacts, and 3) a proposed substrate area where slurry particles adhere to and are swept along with the moving asperity contact. The model is used to interpret data from pin-on-disk friction experiments performed with a fused silica wafer and various polymer polishing pad materials, flooded with 100 nm diameter silica nanoparticle slurries. The results showed that only 18% of the pad asperity junction contact area had active particles and contacts outside of the asperity area were 38 times of the asperity junction area. This suggests that 93% of CMP material removal activity results from particles outside of the asperity/substrate contact.

Solid-silica core/mesoporous-silica shell composite abrasives: synthesis, characterization, and the effect of mesoporous shell structures on CMP

The silica-based composite abrasive particles containing solid silica (sSiO2) cores and mesoporous silica (mSiO2) shells exhibit potential applications in efficient and damage-free chemical mechanical polishing (CMP) due to their special mechanical and/or chemical characteristics. In this work, the composite particles composed of sSiO2 cores and worm-like mesoporous silica shells (sSiO2/W-mSiO2) or dendritic mesoporous shells (sSiO2/D-mSiO2) were obtained by a modified Stober method combined with a biphase stratification approach. And the effects of mSiO2 shell structures of the silica-based composites on oxide CMP performance and structural stability were further investigated. TEM and XRD analyses revealed that the sSiO2/W-mSiO2 composites exhibited an improved mesochannel organization in silica shells with respect to the sSiO2/D-mSiO2 particles. The polishing results showed that the substrates after finishing with the as-obtained silica-based composite abrasives presented a superior surface quality with respect to conventional solid silica particles with a comparable particle size. Moreover, an improved organization in silica shells contributed to the improvement of surface quality and mechanical stability during CMP processes. In addition, the sSiO2/D-mSiO2 abrasives exhibited an enhanced material removal rate by comparison with the sSiO2/W-mSiO2 under the same CMP conditions. This work provides an experimental basis for exploring the relationship between the polishing performance and the mesoporous shell structure of silica-based composite abrasives.

Design of ceria grafted mesoporous silica composite particles for high-efficiency and damage-free oxide chemical mechanical polishing

Chemical mechanical polishing or planarization (CMP) is a material removal process dominated by mechanical and tribo-chemical assisted friction and wear. The choice of abrasive plays a key role in this process. In this work, the mSiO2/CeO2 composite particles, consisting mesoporous silica (mSiO2) cores and CeO2 nanoparticle coatings, were designed and introduced into oxide chemical mechanical polishing (CMP) as novel abrasives. The abrasives were further characterized in terms of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (STEM-EDX) techniques. Five different abrasive systems were tested in the oxide CMP processes, and their performances were evaluated in terms of material removal rate (MRR) and surface roughness. Particularly, the effects of inner cores of composite abrasives were investigated by comparing mSiO2/CeO2 (meso-silica cores), sSiO2/CeO2 (solid-silica cores), and PS/CeO2 (solid-polystyrene cores). As confirmed by TEM and XPS, the mSiO2/CeO2 composite particles revealed an improved structural stability with respect to PS/CeO2 hybrids, resulting from the formation of Ce-O-Si chemical bonding between SiO2 and CeO2 after high-temperature calcination. Overall, the composite abrasives resulted in a decreased surface roughness and reduced mechanical damage after CMP due to the spring-like effect coming from the elastic component of the PS or the mSiO2 cores, compared with the conventional rigid inorganic ceria abrasives or the mixed compounds (mSiO2+CeO2). In addition, the mSiO2/CeO2 composites exhibited a comparable surface roughness (0.20 vs 0.18 nm) and topographical variation with respect to PS/CeO2 hybrids. However, the material removal rate for the mSiO2/CeO2 abrasives (64 nm/min) was about three times larger than that of the PS/CeO2 abrasives (19 nm/min) under the same CMP conditions. The enhanced removal rate might be related to the improved crystallinity of CeO2 particles and the increased content of Ce3+ ions at the CeO2 surfaces.

Core/shell structured sSiO2/mSiO2 composite particles: The effect of the core size on oxide chemical mechanical polishing

In a typical chemical mechanical polishing (CMP) process, the type, morphology, structure, mechanical, and surface characteristics of abrasive particles play an important role in influencing the material removal process. The novel abrasive particles with special mechanical and/or tribochemical properties have been introduced into CMP processes for the improvement of surface quality and finishing efficiency. In this work, the composite particles containing solid silica (sSiO2) cores and mesoporous silica (mSiO2) shells were prepared via a developed Stöber method using cetyltrimethylammonium bromide as a structure-templating surfactant. The as-synthesized core/shell structured sSiO2/mSiO2 composite particles were characterized by powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and nitrogen sorption–desorption measurements. The effect of the sSiO2 core size of the composite particles on oxide CMP performance was evaluated in terms of surface roughness and material removal rate (MRR). The root-mean-square surface roughness (0.15–0.31nm) of the polished substrates slightly increased with increasing of the sSiO2 core size (168–353nm) of the composites with a comparable mSiO2 shell thickness (16–18nm). The sSiO2/mSiO2 composite particles with a relatively smaller or larger core presented a relatively high MRR for silicon oxide films. These oxide CMP results could be rationalized according to the contact area mechanism and indentation-based mechanism, incorporating the total contact area and chemical reactivity between particles and wafers, and the indentation depth of an abrasive particle onto the substrate surface.

Effect of mixing ratio of non-spherical particles in colloidal silica slurry on oxide CMP

Colloidal silica and fumed silica are common slurry materials for oxide chemical mechanical polishing (CMP). Non-spherical colloidal silica particles are manufactured via a multi-step feeding method to compensate for the material removal rate of colloidal silica slurry, which is lower than that of fumed silica slurry. Additionally, mixed abrasive slurry has been used by combining non-spherical and spherical colloidal silica particles. Experiments were conducted on a 4-inch wafer with silicon dioxide film (SiO 2 , 1-μm thick) and KOH-based colloidal silica slurry. The slurry had spherical colloidal silica particles with the size of 30 nm and 70 nm and non-spherical colloidal silica particles with the size of 70 nm. Effects of different colloidal particles in the oxide CMP were observed under the same pH condition in order to achieve high material removal rate. The mixing ratios were 2:1, 1:1, and 1:2 respectively. The analysis of the particle combinations showed that the mixing of particles with different sizes caused agglomeration and increased the material removal rate. The relatively smaller spherical particles improved the surface roughness and overall performance, especially when mixed with non-spherical particles. Such mixtures of particles with different sizes and shapes mixed at an appropriate ratio can outperform the fumed silica slurry.

Impact of Business Trends on Advanced CMP Process Technology Development

The technology of chemical mechanical polishing (CMP) is directly influenced by business trends within the semiconductor industry. Companies that manufacture devices and integrated circuits can be grouped into three broad industry segments: leading edge, mainstream or established, and emerging technology. Development of new device architectures, new integration schemes, and ultimately new commercial products are often enabled by development of new and optimized CMP processes. This is illustrated with examples from three different CMP development projects: oxide CMP for advanced silicon substrates with inlaid features requiring sub-nanometer topography, Pt CMP for high temperature vias, and polymer CMP for an advanced packaging interposer design.

Material Removal Behavior of Nano-Sized Cerium Hydroxide Abrasive Slurry for Chemical Mechanical Polishing

Microscratch induced by Chemical Mechanical Polishing (CMP) is a chronic problem to device yield-killing and its criticality becomes more important in sub-14nm device manufacturing. In order to mitigate scratching during CMP, minimizing abrasive particle size without sacrificing removal rate is the most important parameter. For this purpose, less than 5nm sized cerium hydroxide-based (nano-sized cerium hydroxide-based, NC) particle is utilized as oxide CMP slurry, which is much smaller than conventionally used calcined ceria slurry (100nm – 200nm in particle size). Although it shows more than 80% microscratch reduction obtained by NC slurry in poly CMP process, its polishing behavior is not well understood. In this study, tetraethyl orthosilicate (TEOS) oxide removal behavior with NC slurry is explored by a series of experiments involving tribological analysis. Based on experimental results, this study emphasizes surface reaction as a dominant parameter to determine removal rate rather than mechanical aspect of material removal.

Material Removal Behavior of Nano-Sized Cerium Hydroxide Abrasive Slurry for Chemical Mechanical Polishing

Microscratch induced by Chemical Mechanical Polishing (CMP) is a chronic problem to device yield-killing. In sub-14nm device, its criticality becomes more important due to its structural and process complexity. In order to mitigate scratching during CMP process, minimizing abrasive particle size without sacrificing removal rate is the most important parameter. Uniform size distribution of abrasive particles is critical to reduce scratching as well. For this purpose, less than 5nm sized (i.e., nano-sized) cerium hydroxide-based particle (NSC) is utilized as oxide CMP slurry. This size is much smaller than conventionally used calcined ceria slurry (100nm – 200nm in particle size). The slurry that is used in this experiment is designed to have high TEOS selectivity to polysilicon. And the effect of NSC on the microscratch generation is investigated with stop on polysilicon CMP process for so-called ‘dummy gate’ formation and experimental results show more than 80% microscratch reduction compared with process of record (POR) process. Moreover, microscratch size is much smaller than calcined ceria slurry induced microscratch. However, although dramatic microscratch reduction is obtained with NSC, its polishing behavior has not been well understood. In this study, material removal behavior with NSC is explored by a series of experiments involving tribological analysis. 300mm tetra-ethyl-ortho-silicate (TEOS) oxide is used for the experiments, and non-Prestonian TEOS removal behavior with respect to down pressure is observed. At low down force regime, TEOS removal rate is linearly proportional to down force, which is following Preston equation. However, after certain pressure is reached, TEOS material removal rate increases slowly and slope of removal rate becomes smaller. The effect of rotational speed, retainer ring down force, dilution and additive on the removal rate is also explored. TEOS removal rate increase as rotational speed increase is not as sensitive as down pressure effect, and TEOS removal rate is decreased at high retainer ring down force. Experimental results suggest that TEOS removal mechanism by nano-sized cerium hydroxide particle is different from conventionally used calcined ceria particle. Based on the experimental results, this study emphasizes surface reaction as a dominant parameter to determine removal rate rather than mechanical aspect of material removal. Figure 1

Impact of Business Trends on Advanced CMP Process Technology Development

The technology of chemical mechanical polishing (CMP) is directly influenced by business trends within the semiconductor industry. Companies that manufacture devices and integrated circuits can be grouped into three broad industry segments: leading edge, mainstream or established, and emerging technology. Development of new device architectures, new integration schemes, and ultimately new commercial products are often enabled by development of new and optimized CMP processes. This is illustrated with examples from three different CMP development projects: oxide CMP for advanced silicon substrates with inlaid features requiring sub-nanometer topography, Pt CMP for high temperature vias, and polymer CMP for an advanced packaging interposer design.

Evaluation of oxide chemical mechanical polishing performance of polystyrene coated ceria hybrid abrasives

The spherical polystyrene (PS) coated ceria composite particles with different PS core size were synthesized by an in situ chemical precipitation method. Chemical mechanical polishing (CMP) of silicon dioxide film was performed using the obtained core/shell structured PS/ceria hybrid abrasives and conventional solid ceria abrasives. Four different abrasive systems were tested in the oxide-CMP process and their performances thoroughly evaluated in terms of material removal rate (MRR) and surface roughness. The aim of this work was to explore the effect of core size on oxide-CMP behavior of PS/ceria hybrid abrasives. As confirmed by atomic force microscopy, fewer scratches were detected for the composites by comparison with solid ceria abrasives. For the PS/ceria hybrids with a comparable shell thickness (ca. 10 nm), the MRR increased with the PS core size at the expense of the surface roughness after CMP. The lowest root-mean-square (RMS) roughness (0.19 nm) was achieved for the PS/ceria hybrids with the smallest PS cores (ca. 120 nm), while the highest MRR (195 nm/min) was obtained for the hybrids with the largest cores (ca. 260 nm). This work presents our effort to explore the relationship between the microstructures and the polishing performances of the core/shell structured PS/ceria hybrid abrasives in order to optimize the oxide-CMP performance.