Effect of graphene additions on polishing of silicon carbide wafer with functional PU/silica particles in CMP slurry

2019 ◽  
Vol 12 (05) ◽  
pp. 1950066 ◽  
Author(s):  
Hsien-Kuang Liu ◽  
Chao-Chang A. Chen ◽  
Chun-Jen Chen
Keyword(s):  
Silicon Oxide ◽  
Ph Value ◽  
Removal Rate ◽  
Weight Fraction ◽  
Processing Parameters ◽  
Sonication Time ◽  
Polishing Process ◽  
Improvement Rate ◽  
Sic Wafer ◽  
Polishing Pads

In this paper, a functional ternary slurry consisting of polyurethane (PU) microspheres, graphene oxide (GO) nano platelets and silicon oxide (SiO2) abrasives was used to carry out the polishing process on Si face of 4H-SiC wafers. The processing parameters of the slurry include graphene weight fraction in slurry GO1–GO7 (0.1–0.7[Formula: see text]wt.%), pH value (3–5), and sonication time T5–T15 (5–15[Formula: see text]min). Polishing process is conducted with two kinds of polishing pads A and B, PU and PC (polycarbonate). Results show that material removal rate (MRR) increases with increasing GO weight fraction up to GO5; besides, MRR also increases with increasing sonication time up to T10, and with increasing pH value. Using PU pad, the GO5-T10-pH5-A slurry leads to highest MRR 102.220[Formula: see text]nm/h of the polished SiC wafer. On the other hand, surface roughness improvement rate (SRIR) increases with increasing GO weight fraction up to GO5, and increases with increasing sonication time up to T15. But SRIR is not affected by pH value. Regarding effect of pad type, on average the PU pad results in higher MRR and better SRIR compared with the PC pad. Using PC pad, GO5-T10-pH5-B leads to lower MRR of 87.627[Formula: see text]nm/h. The addition of GO as the ternary slurry demonstrates its better effect on polishing SiC wafers by comparing with the counterpart binary slurry without GO. For example, MRR by the counterpart slurry SiO212-pH5-A is 58.411[Formula: see text]nm/h, which is lower than 102.220[Formula: see text]nm/h by the ternary slurry GO5-T10-pH5-A. Both XPS and Raman spectra demonstrate that the wafer polished by the functional ternary slurry can effectively produce the softer SiO2 reactant layer on SiC wafer, and result in better polishing performance.

Achieving Highly Stable Removal Rate in Small Tool Polishing of Glass Lenses

2020 ◽  
Author(s):  
Urara Satake ◽  
Toshiyuki Enomoto ◽  
Teppei Miyagawa ◽  
Takuya Ohsumi
Keyword(s):  
Removal Rate ◽  
Industrial Applications ◽  
Polishing Process ◽  
The Stability ◽  
Sudden Decrease ◽  
Polishing Pads ◽  
Glass Lenses ◽  
Polishing Pressure ◽  
Small Tool

Abstract The demand for improving the image quality of cameras has increased significantly, especially in industrial applications, such as broadcasting, on-vehicle, security, factory automation, and medicine. Surface of glass lenses, which is a key component of cameras, is formed and finished by polishing using small tools. However, the existing small tool polishing technologies exhibit serious problems including an unstable removal rate with the accumulated polishing time. In concrete, low removal rate at the beginning of the polishing process and sudden decrease in the removal rate during the polishing process significantly deteriorate stability of the removal rate. To improve the stability of the removal rate, we proposed a vibration-assisted polishing method using newly developed polishing pads with titanium dioxide particles in the previous work. Polishing experiments on glass lenses confirmed that the variation in the removal rate was suppressed by the developed polishing method; however, the reason for the improvement, in concrete, the relation between the vibration of polishing pressure and the stability of the removal rate remains unknown. In this study, we investigated and clarified the effect of the vibration of polishing pressure on the surface conditions of polishing pads, which strongly affected removal rate.

Stabilization of Removal Rate in Small Tool Polishing of Glass Lenses

2019 ◽  
Vol 13 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Urara Satake ◽  
Toshiyuki Enomoto ◽  
Teppei Miyagawa ◽  
Takuya Ohsumi ◽  
Hidenori Nakagawa ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Material Removal Rate ◽  
Time Variation ◽  
Material Removal ◽  
Removal Rate ◽  
Polishing Process ◽  
Polishing Pad ◽  
The Stability ◽  
Polishing Pads ◽  
Glass Lenses

The demand for improving the image quality of cameras has increased significantly, especially in industrial fields such as broadcasting, on-vehicle, security, factory automation, and medicine. The surface of glass lenses as a key component of cameras is formed and finished by polishing using small tools. The existing polishing technologies, however, exhibit serious problems including an unstable material removal rate over time. In our previous work, the mechanism of time variation in material removal rate was clarified. Based on the findings, a vibration-assisted polishing method using polishing pads containing titanium dioxide particles was developed for improving the stability of the material removal rate with the accumulated polishing time. Our experiments revealed that the proposed polishing method suppressed the time variation significantly in the material removal rate. The developed polishing pads, however, possessed a short life because of their poor wear resistance; as such, they could not be applied to the mass-production process of lenses. In this study, we applied the vibration-assisted polishing method to the polishing process using commercial polishing pads that exhibit sufficient wear resistance for practical use. To investigate the effect of vibration on the stability of the material removal rate, polishing experiments and the observation of slurry flow on the surface of the polishing pads during the vibration-assisted polishing process were conducted. Based on the findings, a new polishing method utilizing a large-amplitude high-frequency vibration applied to the polishing pressure was developed. In addition, a new polishing method utilizing the overhang of a polishing pad, where the polishing pad was moved to hang over the edge of the workpiece for incorporating periodic dressing processes of the polishing pad surface during the polishing process, was also developed. Our polishing experiments revealed that both the proposed polishing methods improved the stability of the material removal rate significantly over the course of the polishing process.

The Performance and Optimization of Slurry on the Double Sided Polishing Process of Silicon Wafer

2007 ◽  
Vol 359-360 ◽  
pp. 324-328
Author(s):  
Wei Li ◽  
Gang Xiang Hu ◽  
Xiao Dong Hu ◽  
Xiao Zhen Hu
Keyword(s):  
Surface Roughness ◽  
Silicon Wafer ◽  
Process Parameters ◽  
Ph Value ◽  
Removal Rate ◽  
Polished Surface ◽  
Polishing Process ◽  
Stock Removal

This study compares the effectiveness of different polishing slurries for Double Sided Polishing process of Silicon wafer in the polished surface roughness and stock removal rate, discusses the mechanism of Double Sided Polishing for silicon wafer with different type slurries, also the influence of the pH value, temperature and concentration of the slurries are discussed in this paper. Furthermore, by the optimization of the process parameters, the ultra-smooth of polished surface of silicon wafer has been got with higher efficient.

Development of electrical enhanced photocatalysis polishing slurry for silicon carbide wafer

2019 ◽  
Vol 234 (3) ◽  
pp. 401-413 ◽  
Author(s):  
Yan He ◽  
Zewei Yuan ◽  
Kai Cheng ◽  
Zhenyun Duan ◽  
Wenzhen Zhao
Keyword(s):  
Silicon Carbide ◽  
Hydroxyl Radical ◽  
Ph Value ◽  
Uv Light ◽  
Removal Rate ◽  
Chemical Oxidation ◽  
Chemical Effect ◽  
Semiconductor Particles ◽  
Clean Manufacturing ◽  
Sic Wafer

Single-crystal silicon carbide, as one of the most promising next-generation semiconductor materials, should be polished with atomically smooth and damage-free surface to meet the requirements of semiconductor applications. The research presented in this paper aims to develop an electrical enhanced photocatalysis polishing method for atomic smoothing of Si-face (0001) 4H-SiC wafer based on the powerful oxidability of UV photo-excited hydroxyl radical on nano semiconductor particles. The research identifies the influences of photocatalyst, electron capturer, UV light, voltage and pH value by designing the orthogonal fading experiments of methyl orange and thus develops several slurries for electrical enhanced photocatalysis polishing accordingly. It also demonstrates that photocatalyst, UV light, electron capturer, and acid environment being necessaries for the electrical enhanced photocatalysis polishing process. Electricity can effectively prevent the recombination of electrons and holes generated on the surface of semiconductor particles and therefore enhance the polishing efficiency. Five photocatalysts including 5 nm TiO2, P25, ZnO, CeO2 and ZrO2 have envious selectivity to the UV light. The slurry with P25 as the photocatalyst and H2O2 as electron capturer presents best polishing performance among, which provides a material removal rate of about 1.18 µm/h and a surface roughness of about Ra 0.0527 nm in an area of 1.0 × 1.0 µm. Furthermore, it also discusses how the UV light irradiation and electricity promotes the chemical oxidation of hydroxyl radical with SiC by forming “Si-C-O”, “Si-O” and “C-O” on SiC surface. The paper concludes that the proposed electrical enhanced photocatalysis polishing is an effective and clean manufacturing method for SiC wafer without rendering toxic chemical effect on environment and human health.

scholarly journals Study on the Effect of Nano-SiO2in ULSI Silicon Substrate Chemical Mechanical Polishing Process

2006 ◽  
Vol 2006 ◽  
pp. 1-4
Author(s):  
Liu Yuling ◽  
Wang Juan ◽  
Sun Ming ◽  
Liu Chenglin
Keyword(s):  
Silicon Substrate ◽  
Chemical Mechanical Polishing ◽  
Ph Value ◽  
Removal Rate ◽  
Low Ph ◽  
Mechanical Polishing ◽  
Polishing Process ◽  
Chemical Mechanical Polishing Process ◽  
Traditional Function

Both process and mechanical of silicon substrate chemical mechanical polishing (CMP) are studied in detail, and the effects of experiments designed indicate that nano-SiO2grinding particles seem to be acted as catalyzer besides the grinding action during the CMP process. This is different from the traditional function. As a result, in the condition of low pH, the nano-SiO2slurry can be recycled. In the meanwhile, the removal rate can gain stability and pH value does not change obviously.

Performance Analysis of Trihexyltetradecylphosphonium Chloride Ionic Fluid under MQL Condition in Hard turning

2020 ◽  
Vol 17 (1) ◽  
pp. 7629-7647
Author(s):  
A. Pandey ◽  
R. Kumar ◽  
A. K. Sahoo ◽  
A. Paul ◽  
A. Panda
Keyword(s):  
Material Removal Rate ◽  
Feed Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Cutting Speed ◽  
Coconut Oil ◽  
Chip Morphology ◽  
Weight Fraction ◽  
Cutting Fluid ◽  
Depth Of Cut

The current research presents an overall performance-based analysis of Trihexyltetradecylphosphonium Chloride [[CH3(CH2)5]P(Cl)(CH2)13CH3] ionic fluid mixed with organic coconut oil (OCO) during turning of hardened D2 steel. The application of cutting fluid on the cutting interface was performed through Minimum Quantity Lubrication (MQL) approach keeping an eye on the detrimental consequences of conventional flood cooling. PVD coated (TiN/TiCN/TiN) cermet tool was employed in the current experimental work. Taguchi’s L9 orthogonal array and TOPSIS are executed to analysis the influences, significance and optimum parameter settings for predefined process parameters. The prime objective of the current work is to analyze the influence of OCO based Trihexyltetradecylphosphonium Chloride ionic fluid on flank wear, surface roughness, material removal rate, and chip morphology. Better quality of finish (Ra = 0.2 to 1.82 µm) was found with 1% weight fraction but it is not sufficient to control the wear growth. Abrasion, chipping, groove wear, and catastrophic tool tip breakage are recognized as foremost tool failure mechanisms. The significance of responses have been studied with the help of probability plots, main effect plots, contour plots, and surface plots and the correlation between the input and output parameters have been analyzed using regression model. Feed rate and depth of cut are equally influenced (48.98%) the surface finish while cutting speed attributed the strongest influence (90.1%). The material removal rate is strongly prejudiced by cutting speed (69.39 %) followed by feed rate (28.94%) whereas chip reduction coefficient is strongly influenced through the depth of cut (63.4%) succeeded by feed (28.8%). TOPSIS significantly optimized the responses with 67.1 % gain in closeness coefficient.

Determination of cost-efficient cooling power range for improving the performance of internally cooled ultrasonic atomization liquid desiccant dehumidifiers

2020 ◽  
Vol 29 (9) ◽  
pp. 1260-1276
Author(s):  
Zili Yang ◽  
Lu-An Chen ◽  
Ruiyang Tao ◽  
Ke Zhong
Keyword(s):  
Power Efficiency ◽  
Removal Rate ◽  
Operating Conditions ◽  
Cooling Power ◽  
Internal Cooling ◽  
Liquid Desiccant ◽  
Improvement Rate ◽  
Ultrasonic Atomization ◽  
Internally Cooled ◽  
Cost Efficient

Liquid desiccant dehumidifiers (LDDs) can be improved by adding internal cooling. However, the addition of excessive cooling power may deteriorate the system‘s cost-efficiency, whereas the addition of insufficient cooling power leads to negligible performance improvements. The objective of this study is to determine the suitable cost-efficient cooling power range for improving the performance of internally cooled LDDs (IC-LDDs). A novel method and a set of criteria related to the moisture removal rate, cooling-power efficiency ( ηc) and coefficient of dehumidification performance from cooling power ( DCOPcooling) were proposed to determine cost-efficient cooling power. The internally cooled ultrasonic atomization liquid desiccant system (IC-UADS), together with a well-validated model based on the conservation laws of mass and energy and the sensible heat balance, was adopted to demonstrate the analysis. The results showed that, although the dehumidification performance improves with increasing cooling power, the improvement rate decreases, while ηcand DCOPcoolingdecline quickly (by 87.9%). For cost-efficient improvement, the necessary power proportion of internal cooling to the system‘s target dehumidification capacity tends to be stable, which was about 29% for the IC-UADS, and independent of the operating conditions. The results may help to determine the reasonable cooling power range for cost-efficient improvement of IC-LDDs.

scholarly journals Lignocellulose@ Activated Clay Nanocomposite with Hierarchical Nanostructure Enhancing the Removal of Aqueous Zn(II)

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1710 ◽  
Author(s):  
Xiaotao Zhang ◽  
Yinan Hao ◽  
Zhangjing Chen ◽  
Yuhong An ◽  
Wanqi Zhang ◽  
...  
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Weight Ratio ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Hierarchical Nanostructure ◽  
Desorption Temperature ◽  
Desorption Time ◽  
Adsorption Temperature ◽  
Hcl Concentration

A lignocellulose@ activated clay (Ln@AC) nanocomposite with a hierarchical nanostructure was successfully synthesized by the chemical intercalation reaction and applied in the removal of Zn(II) from an aqueous solution. Ln@AC was characterized by N2 adsorption/desorption isotherms and X-Ray Diffraction (XRD), scanning Electron Microscope (SEM), transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis, and the results indicate that an intercalated–exfoliated hierarchical nanostructure was formed. The effects of different adsorption parameters on the Zn(II) removal rate (weight ratio of Ln to AC, Ln@AC dosage, initial Zn(II) concentration, pH value, adsorption temperature, and time) were investigated in detail. The equilibrium adsorption capacity reached 315.9 mg/g under optimal conditions (i.e., the weight ratio of Ln to AC of 3:1, Ln@AC dosage of 1 g/L, initial Zn(II) concentration of 600 mg/L, pH value of 6.8, adsorption temperature of 65 °C, and adsorption time of 50 min). The adsorption process was described by the pseudo-second-order kinetic model, Langmuir isotherm model, and the Elovich model. Moreover, Zn(II) could be easily eluted by HCl, and the effects of HCl concentration, desorption temperature, and ultrasonic desorption time on desorbed amount were tested. Desorption studies revealed that with an HCl concentration of 0.25 mol/L, desorption temperature of 70 °C, and ultrasonic desorption time of 20 min, the maximum desorption capacity and efficiency were achieved at 202.5 mg/g and 64.10%, respectively. Regeneration experimental results indicated that the Ln@AC exhibited a certain recyclable regeneration performance. Due to such outstanding features, the novel Ln@AC nanocomposite proved to have great adsorption potential for Zn(II) removal from wastewater, and exhibited an extremely significant amount of adsorbed Zn(II) when compared to conventional adsorbents.

Achieving High Flatness of Workpiece Edge Shape by Considering Polishing Pressure

2010 ◽  
Vol 447-448 ◽  
pp. 71-75
Author(s):  
Takahiro Miyake ◽  
Toshiyuki Enomoto
Keyword(s):  
Semiconductor Devices ◽  
Silicon Wafers ◽  
Polishing Process ◽  
Model Based ◽  
Polishing Pad ◽  
Experimental Analyses ◽  
Polishing Pads ◽  
Polishing Pressure

In recent years, the achievement of further high flatness of workpiece edge shape is strongly required in mirror finishing. Especially, the edge roll off of silicon wafers as the substrates of semiconductor devices is demanded to decrease in the polishing process for raising the yield of IC chips. Many theoretical and experimental analyses for the edge roll off generation have been already done to meet the demand. The analyses, however, cannot fully account for the obtained edge shape in actual polishing. Concretely, the influence of the polishing pressure as one of the key polishing conditions on the edge roll off has not been clarified. In this study, the influence of the polishing pressure on the edge shape was investigated by the polishing experiments and the edge roll off generation analyses using the model based on the viscoelasticity of the polishing pad, which was proposed in the previous study. And it was revealed that an appropriate polishing pressure is needed to be set for achieving high flatness of workpiece edge shape with the consideration of the properties of applied polishing pads.

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.

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