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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Fundamental Consumables Characterization of Advanced Dielectric and Metal Chemical Mechanical Planarization Processes

Sampurno, Yasa January 2008 (has links)
This dissertation presents a series of studies relating to kinetics and kinematics of inter-layer dielectric and metal chemical mechanical planarization processes. These are also evaluated with the purposes of minimizing environmental and cost of ownership impact.The first study is performed to obtain the real-time substrate temperature during the polishing process and is specifically intended to understand the temperature distribution across the polishing wafer during the chemical mechanical planarization process. Later, this technique is implemented to study the effect of slurry injection position for optimum slurry usage. It is known that the performance of chemical mechanical planarization depends significantly on the polishing pad and the kinematics involved in the process. Variations in pad material and pad grooving type as well as pressure and sliding velocity can affect polishing performance. One study in this dissertation investigates thermoset and thermoplastic pad materials with different grooving methods and patterns. The study is conducted on multiple pressure and sliding velocity variations to understand the characteristic of each pad. The analysis method elaborated in this study can be applied generically.A subsequent study focuses in a slurry characterization technique. Slurry, a critical component in chemical mechanical planarization, is typically a water-based dispersion of fine abrasive particles with various additives to control material removal rate and microscratches. Simultaneous turbidity and low angle light scattering methods under well-defined mixing conditions are shown to quantify the stability of abrasive particle from aggregations. Further contribution of this dissertation involves studies related to the spectral analysis of raw shear force and down force data obtained during chemical mechanical planarization. These studies implemented Fast Fourier Transforms to convert force data from time to frequency domain. A study is performed to detect the presence of larger, defect-causing particles during polishing. In a further application on diamond disc conditioning work is performed to achieve optimum break-in time and an optimum conditioning duty cycle. Studies on spectral analysis are also extended to planarization of shallow trench isolation pattern wafers to monitor the polishing progress in real-time.
102

Achieving High Rates and High Uniformity in Copper Chemical Mechanical Polishing

Nolan, Lucy M Unknown Date
No description available.
103

Thermal effects on subsurface damage during the surface grinding of titanium aluminide

Stone, Wesley Lloyd 05 1900 (has links)
No description available.
104

Visualization of colloidal particle dynamics at a solid-liquid interface

Zettner, Claudia Margaret 12 1900 (has links)
No description available.
105

Mechanical interactions at the interface of chemical mechanical polishing

Shan, Lei 12 1900 (has links)
No description available.
106

POLISHING OF POLYCRYSTALLINE DIAMOND COMPOSITES

CHEN, Yiqing January 2007 (has links)
Doctor of Philosophy (PhD) / This thesis aims to establish a sound scientific methodology for the effective and efficient polishing of thermally stable PCD composites (consisting of diamond and SiC) for cutting tools applications. The surface roughness of industrial PCD cutting tools, 0.06 μm Ra is currently achieved by mechanical polishing which is time consuming and costly because it takes about three hours to polish a 12.7 mm diameter PCD surface. An alternative technique, dynamic friction polishing (DFP) which utilizes the thermo-chemical reactions between the PCD surfaces and a catalytic metal disk rotating at high peripheral speed has been comprehensively investigated for highly efficient abrasive-free polishing of PCD composites. A special polishing machine was designed and manufactured in-house to carry out the DFP of PCD composites efficiently and in a controllable manner according to the requirements of DFP. The PCD polishing process and material removal mechanism were comprehensively investigated by using a combination of the various characterization techniques: optical microscopy, SEM and EDX, AFM, XRD, Raman spectroscopy, TEM, STEM and EELS, etc. A theoretical model was developed to predict temperature rise at the interface of the polishing disk and PCD asperities. On-line temperature measurements were carried out to determine subsurface temperatures for a range of polishing conditions. A method was also developed to extrapolate these measured temperatures to the PCD surface, which were compared with the theoretical results. The material removal mechanism was further explored by theoretical study of the interface reactions under these polishing conditions, with particular emphasis on temperature, contact with catalytic metals and polishing environment. Based on the experimental results and theoretical analyses, the material removal mechanism of dynamic friction polishing can be described as follows: conversion of diamond into non-diamond carbon takes place due to the frictional heating and the interaction of diamond with catalyst metal disk; then a part of the transformed material is detached from the PCD surface as it is weakly bonded; another part of the non-diamond carbon oxidizes and escapes as CO or CO2 gas and the rest diffuses into the metal disk. Meanwhile, another component of PCD, SiC also chemically reacted and transformed to amorphous silicon oxide/carbide, which is then mechanically or chemically removed. Finally an attempt was made to optimise the polishing process by investigating the effect of polishing parameters on material removal rate, surface characteristics and cracking /fracture of PCD to achieve the surface roughness requirement. It was found that combining dynamic friction polishing and mechanical abrasive polishing, a very high polishing rate and good quality surface could be obtained. The final surface roughness could be reduced to 50 nm Ra for two types of PCD specimens considered from pre-polishing value of 0.7 or 1.5 μm Ra. The polishing time required was 18 minutes, a ten fold reduction compared with the mechanical abrasive polishing currently used in industry.
107

The effects of early and delayed finishing and polishing of amalgam restorations on gingival health thesis submitted in partial fulfillment ... restorative dentistry ... /

Zajia, Raul A. January 1984 (has links)
Thesis (M.S.)--University of Michigan, 1984.
108

Occlusal stability following occlusal adjustment a stereophotogrammetric study : a thesis submitted in partial fulfillment ... periodontics ... /

Vale, Jose D. Freitas. January 1970 (has links)
Thesis (M.S.)--University of Michigan, 1970.
109

A study on electrolytic in-process dressing (ELID) grinding of sapphire with acoustic emission monitoring /

Han, Peidong. January 2009 (has links)
Thesis (M.S.)--University of Toledo, 2009. / Typescript. "Submitted as partial fulfillments of the requirements for The Master of Science Degree in Mechanical Engineering." "A thesis entitled"--at head of title. Bibliography: leaves 104-110.
110

Measurement and modeling of fluid pressures in chemical mechanical polishing

Ng, Sum Huan. January 2005 (has links) (PDF)
Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2005. / Steven Danyluk, Committee Chair ; Richard Salant, Committee Member ; Jeffrey Streator, Committee Member ; Michael Sacks, Committee Member ; Dennis Hess, Committee Member ; Leonard Borucki, Committee Member. Includes bibliographical references.

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