Polishing Rate Research Articles

Numerical Analysis in Double-Sided Polishing: Mechanism Exploration of Edge Roll-Off

Understanding the mechanism of stress concentration effects on the surface of semiconductor substrate materials—silicon wafers—in Double-Sided Polishing (DSP) is particularly important for improving polishing quality. In this study, a two-dimensional finite element model is established to study the effect of contact state and stress concentration during polishing on edge roll-off (ERO) and polishing rate uniformity. The variation in this contact state is influenced by changes in wafer thickness and the gap between it and the carrier. The model is validated by experiments and helps to further analyze and interpret the experimental results, identifying six stages of contact states during the polishing process. The research indicates that the phenomenon of stress concentration at the edge of a wafer is caused by the pads creating a large amount of compression at the edge of the wafer. Additionally, there appears to be a threshold value during the polishing process, below which the stress concentration on the wafer changes, thereby altering the magnitude of edge roll-off and, ultimately, affecting overall flatness. This study provides a basis for optimizing the process design.

Enhancing Slurry Stability and Surface Flatness of Silicon Wafers through Organic Amine-Catalyzed Synthesis Silica Sol.

The stability of slurries used for chemical mechanical polishing (CMP) is a crucial concern in industrial chip production, influencing both the quality and cost-effectiveness of polishing fluids. In silicon wafer polishing, the conventional use of commercial neutral silica sol combined with organic bases often leads to slurry instability. To address this issue, this study proposes organic amines-specifically ethanolamine (MEA), ethylenediamine (EDA), and tetramethylammonium hydroxide (TMAOH)-as catalysts for synthesizing alkaline silica sol tailored for silicon wafer polishing fluids. Sol-gel experiments and zeta potential measurements demonstrate the efficacy of this approach in enhancing the stability of silica sol. The quantitative analysis of surface hydroxyl groups reveals a direct correlation between enhanced stability and increased hydroxyl content. The application of the alkaline silica sol in silicon wafer polishing fluids improves polishing rates and enhances surface flatness according to atomic force microscopy (AFM). In addition, electrochemical experiments validate the capability of this polishing solution to mitigate corrosion on silicon wafer surfaces. These findings hold significant implications for the advancement of chemical mechanical polishing techniques in the field of integrated circuit fabrication.

Unveiling the synergistic interaction: Investigating the enhanced mechanism of 4H–SiC chemical mechanical polishing with the addition of sodium silicate and manganese dioxide

Silicon carbide (SiC), the quintessential semiconductor material, poses an acute challenge to the realization of highly efficient ultra-precision processing. This study has investigated the effect of the combined ratio of sodium silicate and manganese dioxide on the polishing rate and surface roughness of 4H–SiC in chemical mechanical polishing (CMP). The synergistic mechanism of sodium silicate and manganese dioxide on slurry spreading performance and particle dispersion stability is characterized by surface wettability, surface tension, scanning electron microscopy, zeta potential analysis and X-ray photoelectron spectroscopic. Based on the above studies, the synergistic mechanism of sodium silicate and manganese dioxide on the CMP of 4H–SiC is attributed to the improvement of the suspension stability of the abrasive as well as the oxidizing ability of the slurry.

(Dielectric Science and Technology Division Poster Award, 1st Place) The Influence of Pad Micro-Features on Chemical Mechanical Polishing (CMP) Performance: Insights from Computational Fluid Dynamics (CFD)

With semiconductor chip dimensions shrinking below 7 nanometers, Chemical Mechanical Planarization (CMP) becomes more critical [1], [2]. To meet the increasing demand for precision and uniformity in the fabrication of wafers and chips, enhancements in CMP consumables and operating conditions are necessary. To address these requirements, novel pad designs have been developed, particularly those that do not require conditioning [3]. It is known that the CMP polishing rate depends on pressure, pad wafer relative velocity, and the distribution of pad asperities [4]. As conventional pads provide small and random contact areas, the external pressure applied by the head determines the material removal rate (MRR) [5] Advanced pads with micro-features provide more contact areas and help deliver consistent pressure and slurry distribution during Chemical Mechanical Polishing (CMP) [6], [7]. This study uses computational fluid dynamics (CFD) to simulate the flow between pad and wafer surfaces to determine how pad surface micro-features affect the CMP process. The abrasive residence time, total fluid pressure, and slurry flow velocity are evaluated for four distinct pad micro-feature geometries: square, square-circle, circle, and ellipse. Increasing the number of edges in the pad micro-feature patterns increases pressure drop, leading to more interaction between pad and slurry and enhancement of MRR. The findings of this study confirm the effectiveness of micro-featured pads in optimizing CMP processes and provide valuable insights into the influence of microfeature geometries on critical parameters for improving the semiconductor fabrication process.[1] J. Seo, Journal of Materials Research, 36, 235–257, Jan, 2021.[2] B. Suryadevara, Advances in Chemical Mechanical Planarization (CMP). Woodhead Publishing, 2021.[3] S. Lee and E. Hwang, “Smart pad fabrication for CMP,” LMA Res Rep, vol. 10, pp. 100–104, 2002.[4] G. Ahmadi and X. Xia, J Electrochem Soc, 148, G99, 2001.[5] X. Xia and G. Ahmadi, Particulate Science and Technology, 20, 187–196, 2002.[6] S. Lee, G. Kim, M. Mcgahay, H. Kim, and H. Cho, “Pad Designs-To navigate the fundamentals of CMP.”[7] M. Mcgahay, G. Kim, S. Lee, H. Cho, and H. Kim, “Critical Feature Size of Polishing Pad and Its Performance.”

Rational utilization of the size and electronic effect of inhibitors enabling high polishing rate with minimum corrosion in copper chemical mechanical polishing

Chemical mechanical polishing (CMP) relies on corrosion to remove excess materials, while also on corrosion inhibitors to ensure post-polished surface quality. The robust adsorption of inhibitors onto metal surfaces typically improves inhibition effectiveness but significantly reduces the polishing rate. In this study, we propose and validate a novel strategy that focuses on the utilization of large-sized physisorption-type inhibitors to address this inherent conflict. By incorporating disproportionated rosin (DR) as the inhibitor, the developed slurry facilely obtained a balance between polishing efficiency and quality for copper CMP. The inhibition mechanism of DR was elucidated through electrochemical characterization, adsorption isotherms, and reactive forcefield molecular dynamics (ReaxFF MD) simulations. The weak physisorption of the inhibitors facilitated their easy removal, resulting in minimal impact on the polishing rate. Additionally, the large-size structure of DR effectively hindered corrosive substances from reaching concave areas not under external force, thereby demonstrating superior inhibition efficacy. The adsorption mode of DR on copper was simultaneously determined through adsorption isotherms and ReaxFF MD simulations, marking the first instance of linking classic adsorption theory with MD simulations. The advantage of the ReaxFF MD simulations over classic MD simulations and density-functional-theory calculations for the metal-inhibitor adsorption systems was also discussed and demonstrated.

Study on carbon allotrope abrasive particles based on C60 molecule for diamond chemical mechanical polishing

In this study, we developed C60 reactive diamond composite particles for the chemical mechanical polishing (CMP) of diamond substrates by applying the high hardness and high reactivity of the C60 molecule. When diamond substrates were polished using these C60 diamond composite particles, the polished surface was found to be superior to that of diamond particles. In addition, when the composite particles were irradiated with ultraviolet light to produce polishing fine particles, the polishing rate was improved by about 30%. These results indicate that the composite nanoparticles that reacted with C60 have the potential to remove even the hardest of diamond substrates.

Chemical mechanical planarization of nanotwinned copper/polyimide for low temperature hybrid bonding

In this study, fully cured low-temperature polyimide (PI) films and 〈111〉, 〈110〉, 〈200〉, and 〈211〉-oriented Cu films on Si wafers were chosen to investigate the grinding effect on Cu/PI pattern wafers. PI is chemically inert and low cost with good mechanical properties, which is a promising material for hybrid bonding. However, it is challenging to remove PI during chemical mechanical planarization (CMP) process. The removal rate of PI is dominated by the abrasive grinding mechanism. By adjusting the mechanical parameters (abrasive type, size, dose, and platen velocity), we explored the desorption/adsorption (Kpad) and repulsion (Krep) coefficients using a modified Langmuir adsorption model. Such a tool enables us to predict and discover the optimal PI grinding interval. Additionally, results showed that the hardness of Cu with different orientations varied and was inversely proportional to the removal rate. It was found that the 〈111〉-oriented nanotwinned Cu (NT-Cu) possessed high surface hardness and low polishing rate, which benefited the CMP process of Cu/PI hybrid joints. The optimal height profile of NT-Cu/PI was adjusted by abrasives and pad types. PI recess was achieved while Cu was protected from further dishing under harsh grinding environment. As characterized by atomic force microscopy, Cu protrusion of 200 nm was obtained, achieving excellent bonding interfaces for the NT-Cu/PI hybrid bonding under a thermal compression bonding (TCB) process at 220 ℃ for 1 h with 8.3 MPa.

Casting Production in Poland Versus European Trends in 21st Century

This article presents changes of the total casting production volumes and of the production of castings made from basic casting alloys in Poland, in Europe and worldwide in years 2001–2021. Analogous casting production parameters were compared for Poland, Europe and countries being the leading European and global manufacturers in years 2001, 2011 and 2021. The leading casting manufacturers in Europe (with the manufacturing volume exceeding 1 million tons in the mentioned years) include Germany, Italy, the Ukraine, France and Spain. For years, the largest casting manufacturer worldwide has been China. In 2001–2021, global casting production increased from ca. 68 million tons to ca. 97 million tons (i.e. by ca. 42%), whereas the European one decreased from ca. 17 million tons to ca. 12 million tons (i.e. by close to 30%). In the analyzed period, the Polish production volume grew from ca. 0.75 million tons to ca. 0.88 million tons (i.e. by ca. 17%). The presented data reveal the decreasing importance of gray cast iron and cast steel and the increasing one of ductile cast iron and aluminum alloys. However, the Polish average annual growth rate for aluminum alloy casting production was 10.3%, whereas the global one was 3% and the European one 0.7%.

Effect of Potassium Ferrocyanide on CMP Performance of Ruthenium in H2O2-based Slurries

As feature size of integrated circuits develops to 7 nm, ruthenium is considered the preferred material to replace traditional Ta/TaN barrier layers. Ruthenium can be electroplated without the need for copper seed crystal layers. However, the removal of the ruthenium barrier layer during the polishing process must be addressed. Therefore, this article studies the promoting effect of potassium ferrocyanide (K4Fe(CN)6) and hydrogen peroxide (H2O2) containing silicon slurries on the rate of ruthenium chemical mechanical polishing. Experiments have shown that the polishing rate of ruthenium is significantly improved by the combined action of K4Fe(CN)6 and H2O2. The stronger hydroxyl radicals is the main factor in achieving a high Ru polishing rate, which accelerates the dissolution and removal of Ru layers by converting the hard Ru layer into softer RuO2 and RuO3 oxide layers. The dependencies of the chemical properties (such as electrochemical impedance spectroscopy and surface morphology) proved that the CMP mechanism using Fenton reaction principally performs chemical oxidation and etching dominant CMP simultaneously. This study is expected to provide ideas and insights for the development and design of a new alkaline polishing solution for ruthenium, which is beneficial for the wider application of ruthenium in the field of integrated circuits.

Controlled Synthesis of Triangular Submicron-Sized CeO2 and Its Polishing Performance.

CeO2 is widely used in the field of chemical-mechanical polishing for integrated circuits. Morphology, particle size, crystallinity, and Ce3+ concentration are crucial factors that affect polishing performance. In this study, we successfully synthesized two novel triangular CeO2 abrasives with similar particle sizes (600 nm) but different morphologies and Ce3+ concentrations using a microwave-assisted hydrothermal method with high-concentration raw materials, and no surfactants or template agents were added. It is generally believed that CeO2 with a higher Ce3+ concentration leads to better polishing performance. However, the results of polishing indicate that CeO2 synthesized at 200 °C, despite its lower Ce3+ concentration, demonstrates outstanding polishing performance, achieving a polishing rate of 324 nm/min, and the Sa of Si wafers decreased by 3.6% after polishing. This suggests that, under similar particle size conditions, the morphology of CeO2 plays a dominant role in the mechanical effects during the polishing process. Additionally, compared to commercial polishing slurries, the synthesized samples demonstrated better polishing performance. This indicates that, in CMP, the pursuit of smaller spherical abrasives may not be necessary. Instead, the appropriate shape and particle size can better balance the material removal rate and surface roughness.

Synergistic effect of abrasive friction and glycine on improving chemical mechanical polishing performance of single-crystal GaN substrate

With the rapid development of the third-generation semiconductor materials, the chemical mechanical polishing rate and surface quality of single-crystal gallium nitride (GaN) substrates have been a research hot-spot. In this work, the synergistic effect of abrasive friction and glycine (Gly) on improving the chemical mechanical polishing (CMP) performance of single-crystal GaN substrate is proposed and studied systematically. The results indicated that the polishing solutions with Gly have a 2.3-fold improvement in material removal rate (MRR) as well as scratch-free surface than that without Gly. The maximum MRR of the single-crystal GaN substrate is 129.4 nm/h with surface roughness (Ra) of 0.64 nm attained by using the polishing solutions containing only 3 wt% potassium persulfate (K2S2O8). In contrast, when Gly is added as a reaction reagent, which can be activated by abrasive friction, the maximum MRR is increased to 304.2 nm/h with Ra of 0.42 nm. Meanwhile, the epitaxial evaluation indicates that two-dimensional (2D) MoS2 grown on processed single-crystal GaN substrate has superior crystalline quality and optical properties. Finally, the polishing mechanism of the single-crystal GaN substrate using the mixed solutions of K2S2O8 and Gly is discussed. The proposed CMP method has potential applications in the semiconductor and microelectronics industries.

Characterization of Ceria Nanoparticles as Abrasives Applied with Defoaming Polymers for CMP (Chemical Mechanical Polishing) Applications.

Chemical mechanical polishing/planarization (CMP) is an essential manufacturing process in semiconductor technologies. This method combines chemical and mechanical forces to smooth the surfaces of wafers. The effectiveness of CMP relies on a carefully chosen slurry, demanding a sophisticated manufacturing technology. This technology must seamlessly integrate both chemical composition and mechanical elements, highlighting the intricate synergy required for successful semiconductor fabrication. Particularly in milling processes, if agglomerated particles due to slurry particle corrosion are present during polishing, uneven polishing, numerous fine scratches occur, leading to an increase in roughness and a deterioration in the quality of the finished surface. In this study, to overcome the issue of particle agglomeration and uneven polishing in commonly used ceria nanoparticle slurries during CMP processes, we investigated the ceria nanoparticle behavior based on styrene-maleic acid (SMA) dispersant polymer applied with three types of defoaming polymers. The investigations are expected to open up the possibility of utilizing ceria nanoparticles with applied defoaming polymer as an abrasive for advanced CMP applications. All samples were characterized by DLS (dynamic light scattering), SEM-EDX (scanning electron microscopy-energy dispersive X-ray spectroscopy), pH, conductivity, viscosity, a 10-day stability test at 60 °C, the AF4 test, and the polishing rate efficiency test. Our research demonstrates a significant improvement achieved through the use of SMA dispersant polymer, resulting in a polishing selection ratio exceeding 80 for oxide and nitride films. The G-336 defoaming polymer utilized here is expected to serve as a viable alternative in CMP processes by providing stable uniformity.

Electrolyte Effect on Photoetching of Gallium Nitride

The limited material removal rate of conventional chemical mechanical polishing (CMP) significantly hinders the fabrication efficiency and surface quality, thereby preventing the development of gallium nitride (GaN)-based devices. Moreover, the incorporation of photoelectrochemistry in CMP has garnered increasing attention because of its potential to enhance the quality and efficiency of the GaN process. However, a considerable gap still exists in the comprehensive understanding of the specific photoelectrochemical (PEC) behavior of GaN. Here, we report the influence of the electrolyte on the PEC etching of GaN. Various acids and bases were tested, with their pH being carefully adjusted. The concentrations of the cations and anions were also examined. The results showed that photocorrosion/photoetching was more pronounced in sulfuric acid, phosphoric acid, and nitric acid environments than in alkaline environments, but it was less pronounced in hydrochloric acid. Furthermore, the effects of pH and anion concentration on photoetching were investigated, and the results revealed that photoetching in acidic environments weakened with increasing pH levels and diminished with increasing sulfate concentration. The underlying reasons contributing to this observation were explored. These findings provide ideas for improving the photoetching efficiency of GaN, thereby enriching the photoelectrochemical mechanical polishing (PECMP) technology of GaN.

In Situ Analysis of the Effect of Ultrasonic Cavitation on Electrochemical Polishing of Additively Manufactured Metal Surfaces

Abstract The effects of a hybrid process that combines ultrasonic cavitation and electrochemical polishing on the electrochemical behavior and the resulting surface characteristics of additively manufactured 316-L stainless steel were investigated. In situ potentiodynamic scans and electrochemical impedance spectroscopy (EIS) were conducted to gain a fundamental understanding of the effect of ultrasonic cavitation on the electrochemical processes involved, considering the influence of electrolyte temperature at 60 and 70 °C. The potentiodynamic scans revealed that increasing the ultrasonic excitation amplitude from 20 to 80 µm at 20 µm intervals and temperature from 60 to 70 °C led to reduced polishing resistance, and elevated passivation current density at equivalent applied potentials, thus leading to an increased polishing rate. These findings are attributed to intensified cavitation near the material surface, which promoted anodic dissolution reactions and accelerated the polishing rate. In situ EIS measurements provided valuable information on the charge transfer resistance and double-layer capacitance and their influence on the hybrid process. Specifically, higher ultrasonic amplitudes and elevated temperatures contributed to enhanced electrical double-layer formation and ion adsorption, resulting in a faster rate of polishing, indicating the efficacy of the hybrid process. These findings enhance our understanding of the complex interactions between ultrasonic cavitation and electrochemical dissolution processes that occur during ultrasonic cavitation-assisted electrochemical polishing. The research provides valuable insights for optimizing the process and its potential application in the post-processing of metal additive manufactured parts.

Material removal model for magnetorheological polishing considering shear thinning and experimental verification

To establish a more accurate magnetorheological polishing material removal model, the shear thinning effect of magnetorheological polishing solution under high shear rate conditions was analyzed based on magnetic dipole theory, and the two-particle chain junction model was used to analyze the force of magnetic particles in magnetorheological polishing solution, and the shear yield stress of magnetic chain under tilted condition was obtained, and the magnetorheological polishing material removal model considering shear thinning was established by combining the modified Preston equation. The effect of shear thinning on the magnetorheological polishing material removal model was analyzed. The calculated results of the model are compared with the experimental data of magnetorheological polishing material removal, and the results show that the material removal model considering shear thinning can accurately predict the material removal rate of magnetorheological polishing, especially the trend of decreasing material removal rate of magnetorheological polishing at high shear rate is effectively predicted.

Polishing Mechanism of CMP 4H-SiC Crystal Substrate (0001) Si Surface Based on an Alumina (Al2O3) Abrasive.

Silicon carbide, a third-generation semiconductor material, is widely used in the creation of high-power devices. In this article, we systematically study the influence of three crucial parameters on the polishing rate of a silicon carbide surface using orthogonal experiments. By optimizing the parameters of chemical mechanical polishing (CMP) through experiments, we determined that the material removal rate (MRR) is 1.2 μm/h and the surface roughness (Ra) is 0.093 nm. Analysis of the relevant polishing mechanism revealed that manganese dioxide formed during the polishing process. Finally, due to the electrostatic effect of the two, MnO2 adsorbed on the Al2O3, which explains the polishing mechanism of Al2O3 in the slurry.

Fabrication of self-standing large (111) single crystal diamond using bulk growth of (100) CVD diamond and lift-off process

Diamond (111) plane is superior in impurity doping and quantum spin control to (100) plane, however, there are many technical issues in mass production of the substrate, such as a smaller seed substrate size, low removal rate of polishing, and low growth rate. In this study, a large (111) single crystal diamond substrate of 7 mm × 6 mm was fabricated by growing and processing bulk (100) CVD single crystal. Furthermore, using this as a seed substrate, a (111) self-standing plate was fabricated using the lift-off method. The FWHM of the X-ray rocking curve was 46 arcsec and that of the Raman peak was 2 cm−1. This method can be applied to fabrication of any high index plane such as (113) and can be utilized to fabrication of substrate for electronic and quantum devices, device processing to fabricate vertical structure.

Mechanism Exploration of the Effect of Polyamines on the Polishing Rate of Silicon Chemical Mechanical Polishing: A Study Combining Simulations and Experiments.

Polyamines have become important chemical components used in several integrated circuit manufacturing processes, such as etching, chemical mechanical polishing (CMP), and cleaning. Recently, researchers pointed out that polyamines can be excellent enhancers in promoting the material removal rate (MRR) of Si CMP, but the interaction mechanism between the polyamines and the silicon surface has not been clarified. Here, the micro-interaction mechanisms of polyamines, including ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and pentaethylenehexamine (PEHA), with the Si(1, 0, 0) surface were investigated through molecular dynamics (MD) simulations using the ReaxFF reactive force field. Polyamines can adsorb onto the Si(1, 0, 0) surface, and the adsorption rate first accelerates and then tends to stabilize with the increase in the quantity of -CH2CH2NH-. The close connection between the adsorption properties of polyamines and the polishing rate has been confirmed by CMP experiments on silicon wafers. A comprehensive bond analysis indicates that the adsorption of polyamines can stretch surface Si-Si bonds, which facilitates subsequent material removal by abrasive mechanical wear. This work reveals the adsorption mechanism of polyamines onto the silicon substrate and the understanding of the MRR enhancement in silicon CMP, which provides guidance for the design of CMP slurry.

Effect of Ferric Catalyst on Chemical Decomposition of Polyimide-Film-Surface for Enhancing Chemical–Mechanical-Planarization Polishing-Rate

In semiconductor devices, flexible displays and microelectromechanical systems (MEMS), polyimide has been utilized as a protecting layer, interlayer dielectric polymer for thin-film metallization and low-stress polymer for wafer-level packaging. Since, it has low stress, low thermal coefficient of expansion, low moisture, high modulus, good ductility, thermal stability, high glass transition temperature, and low process cost. However, the applications of polyimide required estentially chemical-mechanical-planarization (CMP) of the polyimide-film-surface. that can be challenging to enhance the polishing rate of the polyimide-film-surface because of the hard and covalently bonded nature of the polyimide-film surface.In this study, to enhance chemical dominant CMP, the chemical decomposition of the polyimide-film-surface was performed by hydrolysis reaction between ferric ions and oxygen atoms covalently bonded with pyromellitimide on the polyimide-film-surface during CMP, as shown in Fig. 1. The polyimide-film polishing rate was estimated as a function of ferric catanylst concentration in the CMP slurry;surprisingly, the polyimide film polishing rate(i.e., 1465A/min) peaked at a specific(i.e., 0.05wt%) ferric catalyst concentration, as shown in Fig. 2. This result indicates that the degree of chemical decomposition during CMP could be principally determined by ferric nitrate concentration. The details of both chemical and mechanical dominant polishing mechanisms will be presented. In addition, the evidence of the chemical composition of the polyimide-film-surface will be demonstrated, depending on the ferric catalyst concentation in the CMP slurry. Figure 1

Silicon-Germanium on Insulator CMP Slurry Designed with Oxidant and Accelerator Heading an Amine Functional Group for Remarkably Enhancing Polishing Rate

High quality single crystal silicon-germanium-on-insulator (SGOI) has a potential to enable the next generationof photonic and electronic devices. However, to utilize an SGOI structure, a high SiGe-film polishing rate isnecessary (i.e., > 200 nm/min) for polishing the facet crystalline SiGe during the fabrication of SiGe on insulatorthrough epitaxial growth processes.In previous studies, amine-based chemicals as SiGe-film polishing rate accelerators have been reported, butthere were limitations in increasing the SiGe-film polishig rate by considering only the chemical reaction of SiGe-film surface. In this study, for the first time, both oxidant(i.e., H2O2) and accelerator with amine functional groups(i.e., triethanolamine) were designed, resulting in a surprising increase in the SiGe-film polishing rate of 270nm/min, as shown Fig. 1a.The SiGe chemical mechanical planarization (CMP) mechanism was clearly demonstrated by preciselyinvestigating both chemical properties(i.e., GeO2 spectra intensity via X-ray photoelectron spectroscopy) andmechanical properties(i.e., electrostatic repulsive force between colloidal silica abrasives and the SiGe-film viaelectrophoretic light scattering). The remarkable enhancement of the SiGe-film polishing rate for oxidant andtriethanolamine was the result of (i) minimizing the loss of degree of SiGe surface oxidation, as shown Fig. 2, (ii)enhancing degree of adsorption of the CMP slurry on the polished SiGe-film surface during CMP, and (iii)decreasing the electrostatic repulsive force between colloidal silica abrasives and the SiGe-film surface, as shownFig 1b. Finally, successful removal of the facets in SiGe on insulator wafers was achieved, securing excellentsurface roughness characteristics. SiGe-film polishing mechanism and the SiGe slurry characteristics will bepresented in detail. Figure 1