Fundamental Studies on the Mechanisms of Oxide CMP

2000 ◽  
Vol 613 ◽  
Author(s):  
Uday Mahajan ◽  
Seung-Mahn Lee ◽  
Rajiv K. Singh
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Wear Rate ◽  
Removal Rate ◽  
Polished Surface ◽  
Electrostatic Repulsion ◽  
Polishing Process ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Slurry Stability

ABSTRACTIn this paper, results of studies on the addition of salt to a polishing slurry, in terms of its effect on slurry stability, SiO2 polishing rate and surface roughness of the polished surface are presented. Three salts, viz. LiCl, NaCl and KCl were selected, and three concentrations were tested. Polishing rate measurements using these slurries show that adding salt leads to increased removal rate without affecting surface roughness significantly. Based on these results, we can say that the agglomerates formed by adding salt to the slurry are fairly soft and easily broken during the polishing process. In addition, turbidity and particle size measurements show that significant coagulation of the particles in the slurry occurs only at the highest salt concentration, and is fastest for LiCl and NaCl, with KCl showing the slowest coagulation. From these results, it can be concluded that the enhancement in polish rate is due to increased contact at the wafer-pad-slurry interface, and not due to formation of larger agglomerated particles in the slurry. This is because of reduced electrostatic repulsion between these three surfaces, due to the screening of their negative surface charge by the metal ions in solution, resulting in a higher wear rate.

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.

Mechanochemical Polishing of Single Crystal Diamond with Mixture of Oxidizing Agents

2006 ◽  
Vol 315-316 ◽  
pp. 852-855 ◽  
Author(s):  
Cheng Yong Wang ◽  
C. Chen ◽  
Yue Xian Song
Keyword(s):  
Surface Roughness ◽  
Single Crystal ◽  
Smooth Surface ◽  
Removal Rate ◽  
Polishing Process ◽  
Iron Plate ◽  
Oxidizing Agents ◽  
Single Crystal Diamond ◽  
Lower Temperature ◽  
And Control

In order to achieve the smooth surface of diamond, several kinds of mixture oxidizing agents have been used to polish the single crystal diamond by a designed polishing apparatus. The existing of graphite and amorphous carbon has been found in the surface of diamond after polishing. The mechanochemical actions of oxidizing agents and the polishing iron plate have been proved. The mixture of oxidizing agents can decrease the polishing temperature so that the super-smooth surface of single crystal diamond can be achieved at lower temperature. The method provided is benefit not only to simplify polishing device and control the polishing process, but also to improve the removal rate and surface roughness.

Research on Ultra-Precision Machining Technology for KTP

2004 ◽  
Vol 471-472 ◽  
pp. 473-476 ◽  
Author(s):  
Ju Long Yuan ◽  
Fei Yan Lou ◽  
Zhi Wei Wang ◽  
M. Chang ◽  
W.P. Du ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Frequency Conversion ◽  
Removal Rate ◽  
Nonlinear Coefficient ◽  
Damage Threshold ◽  
Green Laser ◽  
Machining Process ◽  
Polished Surface ◽  
Nonlinear Frequency ◽  
Ultra Precision

Potassium Titanium Oxide Phosphate (KTP) is a new nonlinear frequency-conversion crystal. It has chemical stability, high nonlinear coefficient, high damage threshold, easily-polished surface, and a broad transparency range. It is be used in solid green laser with medium and low power widely. The requirement for surface roughness is less than 1nm.In this paper, the removal rate and surface roughness are discussed with different velocity, pressure and size of abrasive powder. In order to satisfy the requirement, new polishing techniques with ultra-precision plane polishing machine (Nanopoli-100), and fine AL2O3, SiO2 powders are proposed in this study. The final surface roughness of the KTP is less than 1nm.The machining process and characteristics are also indicated.

scholarly journals An overview of conventional and non-conventional techniques for machining of titanium alloys

2020 ◽  
Vol 7 ◽  
pp. 34 ◽  
Author(s):  
Samuel Ranti Oke ◽  
Gabriel Seun Ogunwande ◽  
Moshood Onifade ◽  
Emmanuel Aikulola ◽  
Esther Dolapo Adewale ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Wear Rate ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Metal Removal ◽  
Removal Rate ◽  
High Volume ◽  
Future Research ◽  
Tool Wear Rate ◽  
The Common

Machining is one of the major contributors to the high cost of titanium-based components. This is as a result of severe tool wear and high volume of waste generated from the workpiece. Research efforts seeking to reduce the cost of titanium alloys have explored the possibility of either eliminating machining as a processing step or optimising parameters for machining titanium alloys. Since the former is still at the infant stage, this article provides a review on the common machining techniques that were used for processing titanium-based components. These techniques are classified into two major categories based on the type of contact between the titanium workpiece and the tool. The two categories were dubbed conventional and non-conventional machining techniques. Most of the parameters that are associated with these techniques and their corresponding machinability indicators were presented. The common machinability indicators that are covered in this review include surface roughness, cutting forces, tool wear rate, chip formation and material removal rate. However, surface roughness, tool wear rate and metal removal rate were emphasised. The critical or optimum combination of parameters for achieving improved machinability was also highlighted. Some recommendations on future research directions are made.

A Study on Surface Quality of GaN with CMP Polishing Process

2011 ◽  
Vol 291-294 ◽  
pp. 1764-1767
Author(s):  
Wei Li ◽  
Ming Ming Ma ◽  
Bin Hu
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Gallium Nitride ◽  
Surface Quality ◽  
Chemical Reaction ◽  
Experimental Result ◽  
Precision Machining ◽  
Polishing Process

This paper introduced a polishing process for planarization of gallium nitride (GaN) wafer by polishing slurry that is made up by the chemical reaction with H2O2 solution and iron. Some different polishing parameters in the polishing process has been analyzed, which affect the surface quality of wafers, such as slurry particle size, polishing times, polishing slurry etc., and trying to improve the polishing process by optimization of the polishing parameters. The experimental result showed that this polishing method has an effect on the surface quality of GaN wafers, finally, the efficient and precision machining with surface roughness of GaN wafers of Ra0.81 nm has been gained by the CMP polishing process.

A Novel Tape and Diamond Process Developed for Polishing Hard Substrates

2015 ◽  
Vol 656-657 ◽  
pp. 416-421
Author(s):  
Rong Hwei Yeh ◽  
T.M. Chao ◽  
Cheng Kuo Lee ◽  
A.H. Tan
Keyword(s):  
Surface Roughness ◽  
Removal Rate ◽  
Lower Surface ◽  
Polished Surface ◽  
Closed Chamber ◽  
Glass Substrates ◽  
Nominal Size ◽  
Hard Glass ◽  
High Removal Rate ◽  
Diamond Abrasive

A nanoscale polish process with improved desired characteristics of low roughness and low scratch counts has been developed using a novel polish tape and diamond abrasive on hard glass substrates. For an improved polishing performance with high removal rate properties and preventing scratches, a novel tape was developed having a nanofiber level, densified surface and a flatter surface by slenderizing the fiber and dispersing ultrafine fiber using an innovative technique. Using this novel polishing tape with a fiber size of 200nm, one can produce a 17% lower surface roughness (Ra) (from 1.05A to 0.87A) and a reduced polished surface scratch count of 53 reduced to 18. The novel nanocluster diamond abrasive is synthesized from carbon atoms of explosives created by detonation in a closed chamber under an oxygen leaked atmosphere ambient. Several crystals are bonded together by layers of non-diamond carbon and other elements, forming aggregates with a nanocluster structure. Using this novel nanocluster diamond along with an ultra-fine diamond mixture with a nominal size of 15nm, one is able to produce an improvement of a 48% lower surface roughness Ra (from 0.87A to 0.45A) and a lower polishing surface scratch count reduced from 18 to 7. Overall, these results indicate that a smoother and a reduced scratch polished substrate results in a significant improvement in disk defects and related magnetic performances.

Optimization of Electric Discharge Machining Parameters of Al-7%Si-4%Mg with 20% of Red Mud Metal Matrix Composites

2014 ◽  
Vol 941-944 ◽  
pp. 1973-1976
Author(s):  
B. Geetha ◽  
K. Ganesan
Keyword(s):  
Surface Roughness ◽  
Wear Rate ◽  
Tool Wear ◽  
Material Removal Rate ◽  
Electric Discharge ◽  
Material Removal ◽  
Removal Rate ◽  
Tool Wear Rate ◽  
Peak Current ◽  
Pulse On Time

An investigation was carried out to find out the influence of process parameters on surface roughness (SR) and material removal rate (MRR) in electric discharge machine of Al-7%Si-4%Mg with 20% of red mud Metal Matrix Composites since electric discharge machining is a thermo-electric machining process, an electronic die sinking electric discharge machine was used to drill holes in the composite work piece, copper is used as tool material. Experiment was carried out to find surface roughness, material removal rate and tool wear rate by varying the peak current, flushing pressure of dielectric fluid and pulse on time. It was found that the surface roughness of composite metal increases with the increase peak current ,pulse on time and flushing pressure due larger and deeper craters on the drilled surface. It was also found that there was increase in metal removal rate with the increase in peak current and flushing pressure and slightly decreases with the increase in pulse on time due carbon deposits on the electrodes. Experimental analysis is carried using Taguchi’s Design of Experiment method with various parameters like peak current, flushing pressure of dielectric fluid and pulse on time to identify the key factors that influence the surface roughness, material removal rate and tool wear rate. It was found that the peak current was the most significant parameter that influences surface roughness, material removal rate and tool wear rate. The Taguchi experiments results confirm the actual results obtained from the numerical calculation.

ELECTRICAL DISCHARGE MACHINING OF Al/7.5% Al2O3 MMCs USING ROTARY TOOL AND Al2O3 POWDER

2017 ◽  
Vol 24 (02) ◽  
pp. 1750018 ◽  
Author(s):  
SAEED DANESHMAND ◽  
BEHNAM MASOUDI ◽  
VAHID MONFARED
Keyword(s):  
Surface Roughness ◽  
Wear Rate ◽  
Tool Wear ◽  
Material Removal Rate ◽  
Material Removal ◽  
Pulse Current ◽  
Removal Rate ◽  
Tool Wear Rate ◽  
Rotary Tool ◽  
Pulse On Time

Nowadays, composites are used in different parts of industries and it is one of the most important subjects. The most widely used reinforcements in metal matrix composites are Al2O3 and SiC fibers and particles which may be used in cutting-edge functional and structural applications of aerospace, defense, and automobile industries. Depending on the type of powder used, composite materials are difficult to machine by conventional cutting tools and methods. The most appropriate way for machining of these composites is electro discharge. For the reason of improving the surface quality, tool wear rate and material removal rate and reducing the cracks on the surface, Al2O3 powder was used. In this study, the effect of input parameters of EDM such as voltage, pulse current, pulse on-time and pulse off-time on output parameters like material removal rate, tool wear rate and surface roughness in both conditions of the rotary tool with powder mixed dielectric EDM and the stationary tool excluding powder mixed dielectric were investigated. The critical parameters were identified by variance analysis, while the optimum machining parameter settings were achieved via Taguchi method. Results show that using of powder mixed dielectric and rotary tool reduce the tool wear rate, surface roughness and the cracks on the surface significantly. It is found also that using of powder mixed dielectric and rotary tool improve the material removal rate due to improved flushing action and sparking efficiency. The analysis of variance showed that the pulse current and pulse on-time affected highly the MRR, TWR, surface roughness and surface cracks.

An Approach to the Influence of Flotative Abrasive Balls on Polishing Process

2006 ◽  
Vol 532-533 ◽  
pp. 393-396 ◽  
Author(s):  
Yong Dai ◽  
Qian Fa Deng ◽  
Xun Lv ◽  
Ju Long Yuan ◽  
Xun Jie Yu
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Removal Rate ◽  
Great Influence ◽  
Work Piece ◽  
Polishing Process ◽  
Soft Contact ◽  
Ball Diameter ◽  
Experiment Device

Polishing with Flotative Abrasive Balls(FABs) is a kind of soft contact polishing means， and the conventional polishing plate and pad are not needed in this case. The pressure of polishing is the flotage which is the upward force that a fluid exerts on the FABs, but the movement of work piece is similar to that in conventional polishing, the removal rate and quality of polishing is influenced by FAB and its flotage. An experiment device is built up and two kinds of FAB are designed and produced. Some primary experiments are carried out in order to investigate the influences of the size of FABs on the removal rate and surface roughness in polishing with FABs. It is found from the experiments that the grain size and the layers of FAB may have great influence on the removal rate of polishing; the surface roughness is mainly decided by the ball diameter and the layers of FAB. The results of experiments are discussed and analyzed, it indicates that the efficiency and quality depend on flotage and the number of active grains when the velocity of workpiece is assigned.

Optimization of Process Parameters on Ti-6Al-4V Using Central Composite Design Method

2011 ◽  
Vol 189-193 ◽  
pp. 1393-1400 ◽  
Author(s):  
M.M. Rahman
Keyword(s):  
Surface Roughness ◽  
Wear Rate ◽  
Process Parameters ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Machining Process ◽  
Peak Current ◽  
Long Pulse ◽  
Pulse On Time

Electrical discharge machining (EDM) is relatively modern machining process having distinct advantages over other machining processes and able to machine Ti-alloys effectively. This paper attempts to investigate the effects of process parameters on output response of titanium alloy Ti-6Al-4V in EDM utilizing copper tungsten as an electrode and positive polarity of the electrode. Mathematical models for material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) are developed in this paper. Design of experiments method and response surface methodology techniques are implemented. The validity test of the fit and adequacy of the proposed models has been carried out through analysis of variance. It can be seen that as the peak current increases the TWR decreases till certain ampere and then increases. The excellent surface finish is investigated in this study at short pulse on time and in contrast the long pulse duration causes the lowest EWR. Long pulse off time provides minimum EWR and the impact of pulse interval on EWR depends on peak current. The result leads to wear rate of electrode and economical industrial machining by optimizing the input parameters. It found that the peak current, servo voltage and pulse on time are significant in material removal rate and surface roughness. Peak current has the greater impact on surface roughness and material removal rate.

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