Surface acidity of colloidal silica and its correlation with sapphire surface polishing

Gu, Yunyun; Wang, Lei; Chen, Jiapeng; Jiang, Zhenlin; Wang, Wenjun; Chen, Haibo; Shen, Juanfen; Zhong, Jiyuan; Meng, Shihang; Li, Jun; Zhu, Yongwei; Sun, Tao

doi:10.1016/j.colsurfa.2022.129718

Cited by 5 publications

(4 citation statements)

References 36 publications

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“…This acidic character can catalyze the hydrolysis/transesterification of PLA [ 37 ]. The silica surface also has a slightly acidic behavior [ 38 ] and could, in principle, provide a further contribution to PLA degradation. However, the main factor accelerating the hydrolysis in samples with higher SiNP content can be ascribed to the increased crystallinity recorded at higher SiNP content.…”

Section: Resultsmentioning

confidence: 99%

Poly(lactic acid)/Plasticizer/Nano-Silica Ternary Systems: Properties Evolution and Effects on Degradation Rate

et al. 2023

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Plasticized nanocomposites based on poly(lactic acid) have been prepared by melt mixing following a two-step approach, adding two different oligomeric esters of lactic acid (OLAs) as plasticizers and fumed silica nanoparticles. The nanocomposites maintained a remarkable elongation at break in the presence of the nanoparticles, with no strong effects on modulus and strength. Measuring thermo-mechanical properties as a function of aging time revealed a progressive deterioration of properties, with the buildup of phase separation, related to the nature of the plasticizer. Materials containing hydroxyl-terminated OLA showed a higher stability of properties upon aging. On the contrary, a synergistic effect of the acid-terminated plasticizer and silica nanoparticles was pointed out, inducing an accelerated hydrolytic degradation of PLA: materials at high silica content exhibited a marked brittleness and a dramatic decrease of molecular weight after 16 weeks of aging.

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Section: Resultsmentioning

confidence: 99%

Poly(lactic acid)/Plasticizer/Nano-Silica Ternary Systems: Properties Evolution and Effects on Degradation Rate

et al. 2023

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“…Single-crystal sapphire specimen (α-Al 2 O 3 ) are currently one of the most widely applied materials in the fields of defense, aerospace, microelectronics, and the medical domain [ 1 , 2 , 3 , 4 ] due to their excellent physicochemical properties and material characteristics, such as high hardness (Mohs hardness 9), high melting point (2045 °C), high light transmittance, high chemical stability, and high thermal stability [ 5 , 6 , 7 , 8 , 9 , 10 ]. Sapphire has not only become the most widely used substrate material for traditional LEDs [ 11 , 12 , 13 , 14 ] but also has a large number of applications in mini/micro-LEDs, which are currently very popular.…”

Section: Introductionmentioning

confidence: 99%

Research on the Preparation and Application of Fixed-Abrasive Tools Based on Solid-Phase Reactions for Sapphire Wafer Lapping and Polishing

Cao,

Zhou,

Wang

et al. 2023

Micromachines

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Single-crystal sapphire specimen (α-Al2O3) have been widely applied in the semiconductor industry, microelectronics, and so on. In order to shorten the production time and improve the processing efficiency of sapphire processing, an integrated fixed-abrasive tool (FAT) based on solid-phase reactions is proposed in this article. The optimal FAT composition is determined using a preliminary experiment and orthogonal experiments. The mass fraction of the abrasives is chosen as 55 wt%, and the mass ratio of SiO2/Cr2O3 is 2. Surface roughness Ra decreased from 580.4 ± 52.7 nm to 8.1 ± 0.7 nm after 150 min, and the average material removal rate was 14.3 ± 1.2 nm/min using the prepared FAT. Furthermore, FAT processing combined with chemical mechanical polishing (CMP) was shortened by 1.5 h compared to the traditional sapphire production process in obtaining undamaged sapphire surfaces with a roughness of Ra < 0.4 nm, which may have the potential to take the place of the fine lapping and rough polishing process.

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“…Liu et al [2] used a neodymium-doped colloidal silica composite abrasive to process sapphire, which improved the processing efficiency and the surface quality of sapphire. Xu et al [3] proposed a new type of catalyst (SoFe III ) to process sapphire; the material removal rate was 1.6 times that of ordinary CMP, and a sapphire wafer with a surface roughness of 0.053 nm was obtained.GU et al [4] combined the low-field nuclear magnetic resonance (LF NMR) and freeze-drying-programmed temperature desorption (TPD) techniques to investigate the true acidity of the surface Si-OH groups, and discovered that there are two possible different mechanisms for sapphire polishing by silica nanoparticles, depending on the pH of the polishing slurries. Kwon [5] analyzed the source of impurity particles, and suggested that the main internal source of impurity particles was the agglomeration of particles in the polishing solution.…”

Section: Introductionmentioning

confidence: 99%

The Preparation and Performance Analysis of a Cr2O3 Gel Abrasive Tool for Sapphire Substrate Polishing

et al. 2022

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In order to solve the problem of the agglomeration of abrasives in traditional hot-pressing abrasive tools, this paper proposes a chromium oxide (Cr2O3) gel abrasive tool with a polyacrylamide gel and a polyimide resin as the bonding agent. The effects of the dispersant and slurry pH on slurry viscosity and the effects of different sintering temperatures on the properties of the abrasives tool were explored. The influence of abrasive tools on the friction coefficient at different sintering temperatures was compared through friction and wear experiments. A comparison experiment of sapphire substrate polishing was carried out to compare the processing effect of the hot-pressing abrasive tool and the gel abrasive tool on the workpiece. The experimental results show that, when the pH value of the slurry is between 8–9 and the mass fraction of the dispersant is 1.5 wt%, the viscosity of the slurry is the lowest. When the sintering temperature is 350 °C, the tensile and flexural strengths of the abrasive tool reach 96 MPa and 42 MPa, and the hardness reaches 72 HRF. In the friction wear test, the friction coefficient is the most stable, and the wear rate of the abrasive tool is the lowest. In the polishing experiment, the gel abrasive tool performs better than the hot-pressing abrasive tool. After processing using the gel abrasive tool, the average surface roughness Ra reaches 2.69 nm, and the flatness PV reaches 0.65 μm; after CMP, the surface roughness Ra reaches 0.67 nm and no scratches appear on the surface of the sapphire.

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Surface acidity of colloidal silica and its correlation with sapphire surface polishing

Cited by 5 publications

References 36 publications

Poly(lactic acid)/Plasticizer/Nano-Silica Ternary Systems: Properties Evolution and Effects on Degradation Rate

Poly(lactic acid)/Plasticizer/Nano-Silica Ternary Systems: Properties Evolution and Effects on Degradation Rate

Research on the Preparation and Application of Fixed-Abrasive Tools Based on Solid-Phase Reactions for Sapphire Wafer Lapping and Polishing

The Preparation and Performance Analysis of a Cr2O3 Gel Abrasive Tool for Sapphire Substrate Polishing

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