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Amos Ullmann - One of the best experts on this subject based on the ideXlab platform.

  • measurements of solid contaminant emission rates from boiling pools
    Chemical Engineering Science, 2000
    Co-Authors: Abraham Dayan, Sylvia Zalmanovich, Amos Ullmann
    Abstract:

    Abstract An experimental study was performed to measure release rates of solid Particles from boiling pools. Sensitivity studies were conducted to reveal the dependence of the Particle carry-over rate on the pool depth, the boiling rate and the vertical distance from the pool surface. Experimental data on Particle concentrations as a function of size at the pool surface are also provided. The study was conducted in a nucleate boiling regime. Tests were performed with distilled water and solid nickel Particles ranging in size from 5 to 40 μm. The test apparatus was made of a cylindrical vessel, 30 cm in diameter and 120 cm in height. Slurry Particle concentrations were on the order of milligrams per cubic centimeter of Slurry. Heat fluxes on the order of 100 kW/m 2 were attained by electrical bottom heating. Corresponding superficial vapor velocities were on the order of several centimeters per second. The phenomenon of Particle emission from the surface of boiling pools pauses major environmental and industrial problems. Such Particles are often undesirable contaminants, especially if toxic or radioactive. Exploration of this subject is of considerable importance to the chemical, nuclear, and power generation industries. The current study provides important data to support safety analyses and development of analytical tools. Surface contamination concentrations and Particle emission rates are essential data for environmental contamination evaluations of spills and boiling, respectively. The study indicates, among other things, that emission rates intensify as pools get shallower. A released Particle flux is strongest near the surface; and at a decreasing pace, diminishes to a constant rate as the distance from the surface is increased. Decontamination factors of the boiling process were found to be in a range of 10 3 –10 4 .

  • measurements of solid contaminant emission rates from boiling pools
    Chemical Engineering Science, 2000
    Co-Authors: Abraham Dayan, Sylvia Zalmanovich, Amos Ullmann
    Abstract:

    Abstract An experimental study was performed to measure release rates of solid Particles from boiling pools. Sensitivity studies were conducted to reveal the dependence of the Particle carry-over rate on the pool depth, the boiling rate and the vertical distance from the pool surface. Experimental data on Particle concentrations as a function of size at the pool surface are also provided. The study was conducted in a nucleate boiling regime. Tests were performed with distilled water and solid nickel Particles ranging in size from 5 to 40 μm. The test apparatus was made of a cylindrical vessel, 30 cm in diameter and 120 cm in height. Slurry Particle concentrations were on the order of milligrams per cubic centimeter of Slurry. Heat fluxes on the order of 100 kW/m 2 were attained by electrical bottom heating. Corresponding superficial vapor velocities were on the order of several centimeters per second. The phenomenon of Particle emission from the surface of boiling pools pauses major environmental and industrial problems. Such Particles are often undesirable contaminants, especially if toxic or radioactive. Exploration of this subject is of considerable importance to the chemical, nuclear, and power generation industries. The current study provides important data to support safety analyses and development of analytical tools. Surface contamination concentrations and Particle emission rates are essential data for environmental contamination evaluations of spills and boiling, respectively. The study indicates, among other things, that emission rates intensify as pools get shallower. A released Particle flux is strongest near the surface; and at a decreasing pace, diminishes to a constant rate as the distance from the surface is increased. Decontamination factors of the boiling process were found to be in a range of 10 3 –10 4 .

Abraham Dayan - One of the best experts on this subject based on the ideXlab platform.

  • measurements of solid contaminant emission rates from boiling pools
    Chemical Engineering Science, 2000
    Co-Authors: Abraham Dayan, Sylvia Zalmanovich, Amos Ullmann
    Abstract:

    Abstract An experimental study was performed to measure release rates of solid Particles from boiling pools. Sensitivity studies were conducted to reveal the dependence of the Particle carry-over rate on the pool depth, the boiling rate and the vertical distance from the pool surface. Experimental data on Particle concentrations as a function of size at the pool surface are also provided. The study was conducted in a nucleate boiling regime. Tests were performed with distilled water and solid nickel Particles ranging in size from 5 to 40 μm. The test apparatus was made of a cylindrical vessel, 30 cm in diameter and 120 cm in height. Slurry Particle concentrations were on the order of milligrams per cubic centimeter of Slurry. Heat fluxes on the order of 100 kW/m 2 were attained by electrical bottom heating. Corresponding superficial vapor velocities were on the order of several centimeters per second. The phenomenon of Particle emission from the surface of boiling pools pauses major environmental and industrial problems. Such Particles are often undesirable contaminants, especially if toxic or radioactive. Exploration of this subject is of considerable importance to the chemical, nuclear, and power generation industries. The current study provides important data to support safety analyses and development of analytical tools. Surface contamination concentrations and Particle emission rates are essential data for environmental contamination evaluations of spills and boiling, respectively. The study indicates, among other things, that emission rates intensify as pools get shallower. A released Particle flux is strongest near the surface; and at a decreasing pace, diminishes to a constant rate as the distance from the surface is increased. Decontamination factors of the boiling process were found to be in a range of 10 3 –10 4 .

  • measurements of solid contaminant emission rates from boiling pools
    Chemical Engineering Science, 2000
    Co-Authors: Abraham Dayan, Sylvia Zalmanovich, Amos Ullmann
    Abstract:

    Abstract An experimental study was performed to measure release rates of solid Particles from boiling pools. Sensitivity studies were conducted to reveal the dependence of the Particle carry-over rate on the pool depth, the boiling rate and the vertical distance from the pool surface. Experimental data on Particle concentrations as a function of size at the pool surface are also provided. The study was conducted in a nucleate boiling regime. Tests were performed with distilled water and solid nickel Particles ranging in size from 5 to 40 μm. The test apparatus was made of a cylindrical vessel, 30 cm in diameter and 120 cm in height. Slurry Particle concentrations were on the order of milligrams per cubic centimeter of Slurry. Heat fluxes on the order of 100 kW/m 2 were attained by electrical bottom heating. Corresponding superficial vapor velocities were on the order of several centimeters per second. The phenomenon of Particle emission from the surface of boiling pools pauses major environmental and industrial problems. Such Particles are often undesirable contaminants, especially if toxic or radioactive. Exploration of this subject is of considerable importance to the chemical, nuclear, and power generation industries. The current study provides important data to support safety analyses and development of analytical tools. Surface contamination concentrations and Particle emission rates are essential data for environmental contamination evaluations of spills and boiling, respectively. The study indicates, among other things, that emission rates intensify as pools get shallower. A released Particle flux is strongest near the surface; and at a decreasing pace, diminishes to a constant rate as the distance from the surface is increased. Decontamination factors of the boiling process were found to be in a range of 10 3 –10 4 .

Sylvia Zalmanovich - One of the best experts on this subject based on the ideXlab platform.

  • measurements of solid contaminant emission rates from boiling pools
    Chemical Engineering Science, 2000
    Co-Authors: Abraham Dayan, Sylvia Zalmanovich, Amos Ullmann
    Abstract:

    Abstract An experimental study was performed to measure release rates of solid Particles from boiling pools. Sensitivity studies were conducted to reveal the dependence of the Particle carry-over rate on the pool depth, the boiling rate and the vertical distance from the pool surface. Experimental data on Particle concentrations as a function of size at the pool surface are also provided. The study was conducted in a nucleate boiling regime. Tests were performed with distilled water and solid nickel Particles ranging in size from 5 to 40 μm. The test apparatus was made of a cylindrical vessel, 30 cm in diameter and 120 cm in height. Slurry Particle concentrations were on the order of milligrams per cubic centimeter of Slurry. Heat fluxes on the order of 100 kW/m 2 were attained by electrical bottom heating. Corresponding superficial vapor velocities were on the order of several centimeters per second. The phenomenon of Particle emission from the surface of boiling pools pauses major environmental and industrial problems. Such Particles are often undesirable contaminants, especially if toxic or radioactive. Exploration of this subject is of considerable importance to the chemical, nuclear, and power generation industries. The current study provides important data to support safety analyses and development of analytical tools. Surface contamination concentrations and Particle emission rates are essential data for environmental contamination evaluations of spills and boiling, respectively. The study indicates, among other things, that emission rates intensify as pools get shallower. A released Particle flux is strongest near the surface; and at a decreasing pace, diminishes to a constant rate as the distance from the surface is increased. Decontamination factors of the boiling process were found to be in a range of 10 3 –10 4 .

  • measurements of solid contaminant emission rates from boiling pools
    Chemical Engineering Science, 2000
    Co-Authors: Abraham Dayan, Sylvia Zalmanovich, Amos Ullmann
    Abstract:

    Abstract An experimental study was performed to measure release rates of solid Particles from boiling pools. Sensitivity studies were conducted to reveal the dependence of the Particle carry-over rate on the pool depth, the boiling rate and the vertical distance from the pool surface. Experimental data on Particle concentrations as a function of size at the pool surface are also provided. The study was conducted in a nucleate boiling regime. Tests were performed with distilled water and solid nickel Particles ranging in size from 5 to 40 μm. The test apparatus was made of a cylindrical vessel, 30 cm in diameter and 120 cm in height. Slurry Particle concentrations were on the order of milligrams per cubic centimeter of Slurry. Heat fluxes on the order of 100 kW/m 2 were attained by electrical bottom heating. Corresponding superficial vapor velocities were on the order of several centimeters per second. The phenomenon of Particle emission from the surface of boiling pools pauses major environmental and industrial problems. Such Particles are often undesirable contaminants, especially if toxic or radioactive. Exploration of this subject is of considerable importance to the chemical, nuclear, and power generation industries. The current study provides important data to support safety analyses and development of analytical tools. Surface contamination concentrations and Particle emission rates are essential data for environmental contamination evaluations of spills and boiling, respectively. The study indicates, among other things, that emission rates intensify as pools get shallower. A released Particle flux is strongest near the surface; and at a decreasing pace, diminishes to a constant rate as the distance from the surface is increased. Decontamination factors of the boiling process were found to be in a range of 10 3 –10 4 .

Yongwu Zhao - One of the best experts on this subject based on the ideXlab platform.

  • a new nonlinear micro contact model for single Particle in the chemical mechanical polishing with soft pad
    Journal of Materials Processing Technology, 2007
    Co-Authors: Yongguang Wang, Yongwu Zhao
    Abstract:

    Abstract A new mathematical micro-contact model based on the Sneddon's equation is developed for chemical–mechanical polishing (CMP) with soft pad. The main feature of the model is incorporation of the large elastic pad deformation for Particle/pad contact. The model strongly shows that the large deformation of the soft pad can significantly affect the micro-contact force between the single sandwiched Particle and the soft pad. Besides, the new model also predicts a nonlinear dependence of indentation depth of a Slurry Particle into the wafer surface on the parameters of the soft pad and the wafer. The predicted results based on the current model are shown to be consistent with the published experimental date. The results are also compared with those calculated by the ZC model, and show that the present model is more complete in describing the micro-contact of wafer/Particle/pad for CMP process. The results and analysis reveal some insights into the micro-contact on the performance of the CMP with soft pad.

  • a micro contact and wear model for chemical mechanical polishing of silicon wafers
    Wear, 2002
    Co-Authors: Yongwu Zhao, Liming Chang
    Abstract:

    Abstract A micro-contact and wear model for chemical–mechanical polishing (CMP) of silicon wafers is presented in this paper. The model is developed on the basis of elastic–plastic micro-contact mechanics and abrasive wear theory. The synergetic effects of mechanical and chemical actions are formulated into the model. A close-form equation of material removal rate from the wafer surface is derived relating to the material, geometric, chemical and operating parameters in a CMP process. The model is evaluated by comparing the theoretical removal rates with those experimentally determined. Good agreement is obtained for both chemically active and inactive polishing processes. The model reveals some insights into the micro-contact and wear mechanisms of the CMP process. It suggests that the removal rate is sensitive to the Particle concentration in the Slurry, more sensitive to the applied load and operating speed and most sensitive to the surface hardness and Slurry Particle size. The model may be used to study the effects of different materials, geometry, Slurry chemistry and operating conditions on CMP processes.

Yeauren Jeng - One of the best experts on this subject based on the ideXlab platform.

  • a material removal rate model considering interfacial micro contact wear behavior for chemical mechanical polishing
    World Tribology Congress III Volume 1, 2005
    Co-Authors: Yeauren Jeng, Payyau Huang
    Abstract:

    Chemical Mechanical Polishing (CMP) is a highly effective technique for planarizing wafer surfaces. Consequently, considerable research has been conducted into its associated material removal mechanisms. The present study proposes a CMP material removal rate model based upon a micro-contact model which considers the effects of the abrasive Particles located between the polishing interfaces, thereby the down force applied on the wafer is carried both by the deformation of the polishing pad asperities and by the penetration of the abrasive Particles. It is shown that the current theoretical results are in good agreement with the experimental data published previously. In addition to such operational parameters as the applied down force, the present study also considers consumable parameters rarely investigated by previous models based on the Preston equation, including wafer surface hardness, Slurry Particle size, and Slurry concentration. This study also provides physical insights into the interfacial phenomena not discussed by previous models, which ignored the effects of abrasive Particles between the polishing interfaces during force balancing.Copyright © 2005 by ASME

  • a material removal rate model considering interfacial micro contact wear behavior for chemical mechanical polishing
    Journal of Tribology-transactions of The Asme, 2005
    Co-Authors: Yeauren Jeng, Payyau Huang
    Abstract:

    Chemical Mechanical Polishing (CMP) is a highly effective technique for planarizing wafer surfaces. Consequently, considerable research has been conducted into its associated material removal mechanisms. The present study proposes a CMP material removal rate model based upon a micro-contact model which considers the effects of the abrasive Particles located between the polishing interfaces, thereby the down force applied on the wafer is carried both by the deformation of the polishing pad asperities and by the penetration of the abrasive Particles.. It is shown that the current theoretical results are in good agreement with the experimental data published previously. In addition to such operational parameters as the applied down force, the present study also considers consumable parameters rarely investigated by previous models based on the Preston equation, including wafer surface hardness, Slurry Particle size, and Slurry concentration. This study also provides physical insights into the interfacial phenomena not discussed by previous models, which ignored the effects of abrasive Particles between the polishing interfaces during force balancing.

  • Tribological Analysis of CMP with Partial Asperity Contact
    Journal of The Electrochemical Society, 2003
    Co-Authors: Yeauren Jeng, Payyau Huang, Wen-chueh Pan
    Abstract:

    Chemical mechanical polishing (CMP) is the most effective technology for global planarization in submicrometer device fabrication. Therefore, much research has been conducted to understand the basic mechanisms of the CMP process. In this study, a model that considers the microcontact mechanism and the grain flow is proposed. The down force acting on the wafer is supported by both the Slurry pressure in the noncontact area and the surface asperity contact force in the contact area. The operation parameter effects on the force distribution, separation distance, and real contact area were investigated. The results show that larger down force and lower relative speed between the wafer and the polishing pad lead to increased contact ratio between the polishing interfaces. Larger Slurry Particle size can decrease the contact ratio.