scholarly journals Using experimental design for the screening and optimization of key factors on silica particles adsorption using magnetic nanoparticles – a case study of chemical mechanical polishing wastewater treatment

2017 ◽  
Vol 12 (3) ◽  
pp. 647-659 ◽  
Author(s):  
Chung-Fu Huang ◽  
An-Chi Huang ◽  
Feng-Jen Chu ◽  
Chia-Ling Lin ◽  
Terng-Jou Wan
Keyword(s):  
Wastewater Treatment ◽  
Magnetic Nanoparticles ◽  
Experimental Design ◽  
Chemical Mechanical Polishing ◽  
Removal Rate ◽  
Average Particle Size ◽  
Mechanical Polishing ◽  
Average Particle ◽  
Key Factors ◽  
Turbidity Removal

This study applied magnetic nanoparticles (MNPs) to chemical mechanical polishing wastewater treatment using experimental design (Plackett–Burman methods) to select the key factors among pH, mixing, Polyaluminum chloride dosage, settling time, MNPs dosage, and temperature and using response surface methodology (RSM) to determine the optimal values of key factors. Research results showed that the key factors influencing processing performance were pH and rpm, and the optimal conditions were a pH of 4.9 and rpm of 68. The turbidity removal rate through RSM simulation was 90%; under this parameter, the actual turbidity removal rate in the experiment was 89%, which was extremely close to the simulation value; this value was also much higher than the nonoptimized removal rate of 61 ± 8%. Additionally, in the subsequent regeneration and reuse experiment involving mixing and ultrasound for desorption and regeneration, the number of recoveries were 4 and 5, respectively. The study showed that the average particle size of MNPs following ultrasonic vibration was reduced; the effect was optimal at 23 to 15 nm. Therefore, a removal rate of over 80% could be maintained for the fifth ultrasonic regeneration, and the energy of the mixing method may not have been sufficient, causing incomplete desorption and a turbidity removal rate of only 71%.

Effect of Different Abrasives on Chemical Mechanical Polishing for Magnesia Alumina Spinel

2020 ◽  
Vol 866 ◽  
pp. 115-124
Author(s):  
Zhan Kui Wang ◽  
Ming Hua Pang ◽  
Jian Xiu Su ◽  
Jian Guo Yao
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chemical Mechanical Polishing ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Key Factors ◽  
Particle Size Analyzer ◽  
Scanning Electron ◽  
Shape And Size

In this paper, a series of chemical mechanical polishing (CMP) experiments for magnesia alumina (Mg-Al) spinel were carried out with different abrasives, and the materials removal rate (MRR) and surface quality was evaluated to explore their different effects. The scanning electron microscope (SEM) and laser particle size analyzer were also employed to test the micro-shape and size distribution of abrasives. Then, the mechanism of different effects with different abrasives was analyzed in CMP for Mg-Al spinel. Those experimental results suggest that different subjecting pressure ratios of abrasives to polishing pad with different abrasive are the key factors leading to difference polishing performances in CMP.

Analysis of Chemical Action of Oxidants in Chemical Mechanical Polishing of SiC Crystal Substrate

2014 ◽  
Vol 1027 ◽  
pp. 213-216
Author(s):  
Su Fang Fu ◽  
Jian Guo Yao ◽  
Li Jie Ma ◽  
Jian Xiu Su
Keyword(s):  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Key Factors ◽  
Chemical Action ◽  
Crystal Substrate ◽  
The Stability ◽  
Polishing Efficiency

Chemical mechanical polishing (CMP) had been considered as the most practical and effective method of achieving an ultra-smooth and non-damage surface in manufacturing SiC crystal substrate. CMP slurry was one of the key factors of CMP technology. In this paper, through investigating the changes of several core factors to evaluate the performance of CMP, such as the material removal rate (MRR), surface roughness Ra, 3D surface profiler, etc., the influence of various slurry and its content on the polishing efficiency and surface finish quality had been studied. The research results showed that different oxidant had different chemical action mechanism, also affecting the stability of CMP slurry and surface quality of specimen; adding suitable an oxidant to slurry could effectively improve the CMP performance.

Optimization of Kaolin Wastewater Treatment Processes Research via Response Surface Methodology

2011 ◽  
Vol 366 ◽  
pp. 361-365
Author(s):  
Li Ping Wu ◽  
Dian Mo Zheng ◽  
Sheng Gan Zhu
Keyword(s):  
Particle Size ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Ph Value ◽  
Removal Rate ◽  
Average Particle Size ◽  
Average Particle ◽  
Good Prediction ◽  
Turbidity Removal ◽  
Treatment Processes

The CCD mathematical model of response surface methodology (RSM) has been used to optimize the process parameters of treating kaolin wastewater, the interaction of the factors on removal rate of turbidity and average particle size of floc such as the flocculation temperature ,the pH value, the dosage of PAC, the dosage of St-PAM were studied. The optimum condition of the effluent disposal via the experiment was as follows: the flocculation temperature was 25°C,the pH value was 6.5, the dosage of PAC was 21.5/mg/L, the dosage of St-PAM was 5/mg/L.In these conditions,the turbidity removal rate of the kaolin wastewater was 97.56%,and the average particle size of flocculation body was 0.994mm. Under the optimum conditions, the removal rate of turbidity and the average particle size of flocculation body was respectively 98.05% and 1.09mm.The model had good prediction effect.

Application of Amorphous Nanoparticle Fe-B Magnetic Fluid in Wastewater Treatment

NANO ◽  
2019 ◽  
Vol 14 (09) ◽  
pp. 1950119 ◽  
Author(s):  
Chuncheng Yang ◽  
Mengchun Yu ◽  
Xiuling Cao ◽  
Xiufang Bian
Keyword(s):  
Wastewater Treatment ◽  
Magnetic Fluid ◽  
Magnetic Particles ◽  
High Efficiency ◽  
Removal Rate ◽  
Average Particle Size ◽  
Oxygen Demand ◽  
Amorphous Structure ◽  
Average Particle ◽  
High Concentration

Amorphous magnetic particles demonstrate excellent comprehensive properties and outstanding characteristics for numerous applications. In this report, magnetic crystalline Fe3O4 and amorphous Fe-B nanoparticles were successfully synthesized and introduced to prepare water-based magnetic fluids. The Fe3O4 and Fe-B particles are homogeneous nanoparticles with an average particle size of [Formula: see text][Formula: see text]nm. The shape of Fe-B amorphous nanoparticles is regular. The saturation magnetizations of Fe-B and Fe3O4 particles are 74 emu/g and 69 emu/g. The use of crystalline Fe3O4 magnetic fluid and amorphous Fe-B magnetic fluid in advanced treatment of high concentration organic wastewater was presented. The removal rate of chemical oxygen demand by using the amorphous Fe-B magnetic fluid reached 96%, about 16% higher than that by using the Fe3O4 magnetic fluid. Moreover, compared with Fe3O4 magnetic fluid, the treatment results demonstrate that the decolorizing effect by using the amorphous Fe-B magnetic fluid was 20% higher. It has been found that the nano-size Fe-B particles in magnetic fluid with amorphous structure led to high efficiency of wastewater treatment due to the catalytic activity.

scholarly journals Agglomeration of Silicon Dioxide Nanoscale Colloids in Chemical Mechanical Polishing Wastewater: Influence of pH and Coagulant Concentration

2019 ◽  
Vol 29 (3) ◽  
pp. 252-271
Author(s):  
Mohamad Zuki Noor Aina ◽  
Jing Yao Sin ◽  
Amane Jada ◽  
Arezoo Fereidonian Dashti ◽  
Mohd Omar Fatehah
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Silicon Dioxide ◽  
Chemical Mechanical Polishing ◽  
Average Particle Size ◽  
Mechanical Polishing ◽  
Second Phase ◽  
Average Particle ◽  
Sulfate Heptahydrate ◽  
Nanoscale Clusters

Abstract Chemical mechanical polishing (CMP) wastewater generated from semiconductor manufacturing industries is known to contain residual organic and inorganic contaminants, i.e. photoresists, acids, including silicon dioxide (SiO2), nanoparticles (NPs) and others. Nanoscale colloids in CMP wastewater have strong inclination to remain in the suspension, leading to high turbidity and chemical oxygen demand (COD). Although various types of pre-treatment have been implemented, these nanoparticles remain diffused in small clusters that pass through the treatment system. Therefore, it is crucial to select suitable pH and coagulant type in the coagulation treatment process. In this research zeta potential and dynamic light scattering measurements are applied as preliminary step aimed at determining optimum pH and coagulant dosage range based on the observation of inter particle-particle behavior in a CMP suspension. The first phase of the conducted study is to analyze nanoscale colloids in the CMP suspension in terms of zeta potential and z-average particle size as a function of pH within a range of 2 to 12. Two types of coagulants were investigated - polyaluminum chloride (PACl) and ferrous sulfate heptahydrate (FeSO4·7H2O). Similar pH analysis was conducted for the coagulants with the same pH range separately. The second phase of the study involved evaluating the interaction between nanoscale colloids and coagulants in the suspension. The dynamics of zeta potential and corresponding particle size were observed as a function of coagulant concentration. Results indicated that CMP wastewater is negatively charged, with average zeta potential of -59.8 mV and 149 d.nm at pH value of 8.7. The interaction between CMP wastewater and PACl showed that positively charged PACl rapidly adsorbed colloids in the wastewater, reducing the negative surface charge of nanoscale clusters. The interaction between CMP wastewater and FeSO4·7H2O showed that larger dosage is required to aggregate nanoscale clusters, due to its low positive value to counter negative charges of CMP wastewater.

Effect of Process Parameters on Material Removal Rate in Chemical Mechanical Polishing of 6H-SiC(0001)

2008 ◽  
Vol 600-603 ◽  
pp. 831-834 ◽  
Author(s):  
Joon Ho An ◽  
Gi Sub Lee ◽  
Won Jae Lee ◽  
Byoung Chul Shin ◽  
Jung Doo Seo ◽  
...  
Keyword(s):  
Material Removal Rate ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Colloidal Silica ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Diamond Particles ◽  
Average Grain Size ◽  
Silica Slurry ◽  
Sic Wafer

2inch 6H-SiC (0001) wafers were sliced from the ingot grown by a conventional physical vapor transport (PVT) method using an abrasive multi-wire saw. While sliced SiC wafers lapped by a slurry with 1~9㎛ diamond particles had a mean height (Ra) value of 40nm, wafers after the final mechanical polishing using the slurry of 0.1㎛ diamond particles exhibited Ra of 4Å. In this study, we focused on investigation into the effect of the slurry type of chemical mechanical polishing (CMP) on the material removal rate of SiC materials and the change in surface roughness by adding abrasives and oxidizer to conventional KOH-based colloidal silica slurry. The nano-sized diamond slurry (average grain size of 25nm) added in KOH-based colloidal silica slurry resulted in a material removal rate (MRR) of 0.07mg/hr and the Ra of 1.811Å. The addition of oxidizer (NaOCl) in the nano-size diamond and KOH based colloidal silica slurry was proven to improve the CMP characteristics for SiC wafer, having a MRR of 0.3mg/hr and Ra of 1.087Å.

Modeling of Polishing Regimes in Chemical Mechanical Polishing

2005 ◽  
Vol 867 ◽  
Author(s):  
Suresh B. Yeruva ◽  
Chang-Won Park ◽  
Brij M. Moudgil
Keyword(s):  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Operating Conditions ◽  
Comprehensive Model ◽  
Mechanical Effects ◽  
Microelectronic Devices ◽  
Asperity Distribution ◽  
Modification Of The Surface

AbstractChemical mechanical polishing (CMP) is widely used for local and global planarization of microelectronic devices. It has been demonstrated experimentally in the literature that the polishing performance is a result of the synergistic effect of both the chemicals and the particles involved in CMP. However, the fundamental mechanisms of material removal and the interactions of the chemical and mechanical effects are not well understood. A comprehensive model for CMP was developed taking into account both the chemical and mechanical effects for monodisperse slurries. The chemical aspect is attributed to the chemical modification of the surface layer due to slurry chemistry, whereas the mechanical aspect is introduced by indentation of particles into the modified layer and the substrate depending on the operating conditions. In this study, the model is extended to include the particle size and pad asperity distribution effects. The refined model not only predicts the overall removal rate but also the surface roughness of the polished wafer, which is an important factor in CMP. The predictions of the model show reasonable agreement with the experimental observations.

A Model for Optimizing Material Removal Rate in Low-Pressure CMP: Effects of Pad Porosity and Abrasive Concentration

2008 ◽  
Author(s):  
Dinc¸er Bozkaya ◽  
Sinan Mu¨ftu¨
Keyword(s):  
Material Removal Rate ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Applied Pressure ◽  
Low Pressure ◽  
Mechanical Polishing ◽  
Low K

The necessity to planarize ultra low-k (ULK) dielectrics [1], and the desire to reduce polishing defects leads to use of lower polishing pressures in chemical mechanical polishing (CMP). However, lowering the applied pressure also decreases the material removal rate (MRR), which causes the polishing time for each wafer to increase. The goal of this work is to investigate effects of pad porosity and abrasive concentration on the MRR.

Investigation on Smoothing Silicon Carbide Wafer With a Combined Method of Mechanical Lapping and Photocatalysis Assisted Chemical Mechanical Polishing

2018 ◽  
Author(s):  
Zewei Yuan ◽  
Kai Cheng ◽  
Yan He ◽  
Meng Zhang
Keyword(s):  
Silicon Carbide ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Combined Method ◽  
Polishing Process ◽  
High Quality ◽  
Quality Surface ◽  
High Quality Surface

The high quality surface can exhibit the irreplaceable application of single crystal silicon carbide in the fields of optoelectronic devices, integrated circuits and semiconductor. However, high hardness and remarkable chemical inertness lead to great difficulty to the smoothing process of silicon carbide. Therefore, the research presented in this paper attempts to smooth silicon carbide wafer with photocatalysis assisted chemical mechanical polishing (PCMP) by using of the powerful oxidability of UV photo-excited hydroxyl radical on surface of nano-TiO2 particles. Mechanical lapping was using for rough polishing, and a material removal model was proposed for mechanical lapping to optimize the polishing process. Several photocatalysis assisted chemical mechanical polishing slurries were compared to achieve fine surface. The theoretical analysis and experimental results indicate that the material removal rate of lapping process decreases in index form with the decreasing of abrasive size, which corresponds with the model developed. After processed with mechanical lapping for 1.5 hours and subsequent photocatalysis assisted chemical mechanical polishing for 2 hours, the silicon carbide wafer obtains a high quality surface with the surface roughness at Ra 0.528 nm The material removal rate is 0.96 μm/h in fine polishing process, which is significantly influenced by factors such as ultraviolet irradiation, electron capture agent (H2O2) and acidic environment. This combined method can effectively reduce the surface roughness and improve the polishing efficiency on silicon carbide and other hard-inert materials.

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