Mechanism of the interaction between Al2O3 and SiO2 during the chemical-mechanical polishing of sapphire with silicon dioxide

Вовк, Е. А.; Budnikov, A. T.; Dobrotvorskaya, M.V.; Krivonogov, S. I.; Dan’ko, A. Ya.

doi:10.1134/s1027451012020188

Cited by 61 publications

(42 citation statements)

References 6 publications

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“…That guess was proven by Vovk who revealed that aluminum silicate with the composition Al 2 SiO 5 could be formed on the polished surface and the siliconcontaining near-surface layer thickness was about 20 nm [24]. The CMP process occurred on the surface activated by the destruction of interatomic bonds after an amorphous silicon-containing layer was removed under the mechanical frictional action of silica particles on sapphire surface.…”

Section: Resultsmentioning

confidence: 81%

Preparation of Ag2O modified silica abrasives and their chemical mechanical polishing performances on sapphire

2017

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Abstract:The chemical mechanical polishing (CMP) process has become a widely accepted global planarization technology. The abrasive material is one of the key elements in CMP. In the presented paper, an Ag-doped colloidal SiO 2 abrasive is synthesized by a seed-induced growth method. It is characterized by time-of-flight secondary ion mass spectroscopy and scanning electron microscopy to analyze the composition and morphology. The CMP performance of the Ag-doped colloidal silica abrasives on sapphire substrates is investigated. Experiment results show the material removal rate (MRR) of Ag-doped colloidal silica abrasives is obviously higher than that of pure colloidal silica abrasives under the same testing conditions. The surfaces that are polished by composite colloidal abrasives exhibit lower surface roughness (Ra) than those polished by pure colloidal silica abrasives. Furthermore, the acting mechanism of Ag-doped colloidal SiO 2 composite abrasives in sapphire CMP is analyzed by X-ray photoelectron spectroscopy, and analytical results show that element Ag forms Ag 2 O which acts as a catalyst to promote the chemical effect in CMP and leads to the increasing of MRR.

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Section: Resultsmentioning

confidence: 81%

Preparation of Ag2O modified silica abrasives and their chemical mechanical polishing performances on sapphire

2017

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“…The specific reaction pathway outlined is likely for most oxide glasses and possibly for other workpiece materials. Other pathways are possible, following the basic steps outlined here, such as by stress corrosion, some other type of direct bonding, or a more complex reaction scheme, such as the formation of an interfacial reaction layer that then chemically reacts or dissolves (eg, see Reference ).…”

Section: Discussionmentioning

confidence: 99%

Influence of partial charge on the material removal rate during chemical polishing

et al. 2018

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A partial charge‐based chemical polishing model has been developed, which can serve as metric for describing the relative polishing material removal rate for different combinations of slurries and workpieces. A series of controlled polishing experiments utilizing a variety of colloidal polishing slurries (SiO2, CeO2, ZrO2, MgO, Sb2O5) and optical materials [single crystals of Al2O3 (sapphire), SiC, Y3Al5O12 (YAG), CaF2, and LiB3O5 (LBO); a SiO2‐Al2O3‐P2O5‐Li2O glass ceramic (Zerodur); and glasses of SiO2:TiO2 (ULE), SiO2 (fused silica), and P2O5‐Al2O3‐K2O‐BaO (Phosphate)] was performed and its material removal rate was measured. As previously proposed by Cook (J Non‐Cryst Solids. 1990;120:152), for many polishing systems, the removal rate is governed by a series of chemical reactions which include the formation of a surface hydroxide, followed by condensation of that hydroxyl moiety with the polishing particle, and a subsequent hydrolysis reaction. The rate of condensation can often be the rate limiting step, thus it can determine the polishing material removal rate. By largely keeping the numerous other factors that influence material removal rate fixed (such as due to particle size distributions, interface interactions, pad topography, kinematics, and applied pressure), the material removal rate is shown to scale exponentially with the partial charge difference (δwp‐s) between the workpiece and polishing slurry particle for many of the slurry‐workpiece combinations indicating that condensation rate is the rate limiting step. The partial charge (δ) describes the equilibrium distribution of electron density between chemically bonded atoms and is related to the electronegativity of the atoms chemically bonded to one another. This partial charge model also explains the age‐old experimental finding of why cerium oxide is the most effective polishing slurry for chemical removal of many workpieces. Some of the slurry‐workpiece combinations that did not follow the partial charge dependence offer insight to other removal mechanisms or rate limiting reaction pathways.

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“…In case of sapphire polishing with colloidal silica, both mechanical and chemical removal mechanisms have been previously proposed . Gutsche and Vovk have reported that during sapphire polishing, an aluminosilicate (A1 2 Si 2 O 7 –H 2 O) is formed on the surface which is then removed by chemical removal, as evidenced by X‐ray photoelectron spectroscopy .…”

Section: Discussionmentioning

confidence: 99%

Nanoplastic removal function and the mechanical nature of colloidal silica slurry polishing

et al. 2018

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The nanomechanical deformations on a broad range of optical material surfaces (single crystals of Al2O3 [sapphire], SiC, Y3Al5O12 [YAG], CaF2, and LiB3O5 [LBO]; a SiO2–Al2O3–P2O5–Li2O glass‐ceramics [Zerodur]; and glasses of SiO2:TiO2 [ULE], SiO2 [fused silica], and P2O5–Al2O3–K2O–BaO [Phosphate]) near the elastic‐plastic load boundary have been measured by nanoindentation and nanoscratching to mimic the nanoplastic removal caused by a single slurry particle during polishing. Nanoindenation in air was performed to determine the workpiece hardness at various loads using a commercial nanoindenter with a Berkovich tip. Similarly, an atomic force microscope (AFM) with a stiff diamond coated tip (150 nm radius) was used to produce nanoplastic scratches in air and aqueous environments over a range of applied loads (~20‐170 μN). The resulting nanoplastic deformation of the nanoscratches were used to calculate the removal function (i.e., depth per pass) which ranged from 0.18 to 3.6 nm per pass for these materials. A linear correlation between the nanoplastic removal function and the polishing rate (using a fixed polishing process with colloidal silica slurry on a polyurethane pad) of these materials was observed implying that: (a) the polishing mechanism using colloidal silica slurry can be dominated by mechanical rather than chemical interactions; and (b) the nanoplastic removal function, as opposed to interface particle interactions, is the controlling factor for the polishing material removal rate. Furthermore, this correlation is consistent with the Ensemble Hertzian Multi‐Gap (EHMG) microscopic material removal rate model described previously. The nanoplastic removal depth was also found to correlate to the measured nanoindentation hardness (H1) of the optical material, scaling as H1−3.5. Two‐dimensional (2D) finite element analysis simulations of nanoindentation showed a similar nonlinear dependence of plastic deformation with the workpiece material hardness. The findings of this study are used to determine an effective Preston coefficient for the material removal rate expression and enhance the predictive nature of the nanoplastic polishing rate for various materials utilizing their material properties.

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Mechanism of the interaction between Al2O3 and SiO2 during the chemical-mechanical polishing of sapphire with silicon dioxide

Cited by 61 publications

References 6 publications

Preparation of Ag2O modified silica abrasives and their chemical mechanical polishing performances on sapphire

Preparation of Ag2O modified silica abrasives and their chemical mechanical polishing performances on sapphire

Influence of partial charge on the material removal rate during chemical polishing

Nanoplastic removal function and the mechanical nature of colloidal silica slurry polishing

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