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This dissertation presents several studies relating to fundamental characterization of CMP consumables in planarization processes. These are also evaluated with the purposes of minimizing environmental impact and reducing cost of ownership (COO).The first study is conducted to obtain the retaining ring wear rate in a typical ILD CMP process and is specifically intended to investigate the effect of retaining ring materials and slot designs during the CMP process. The results show that retaining ring materials have effect on the COF, pad temperature and retaining ring wear rate, while retaining ring slot designs affect the pad surface abruptness. The second study is performed to compare the effect of different retaining ring slot designs on the slurry film thickness within the pad-wafer interface. A novel non-intrusive optical technique, dual emission UV-enhanced fluorescence (DEUVEF), was applied to accurately measure the film thickness of the slurry underneath the wafer during polishing. It is indicated that the optimized retaining ring slot design can significantly reduce the COO of CMP processes by increasing slurry utilization.A COF method is applied to measure the slurry mean residence time (MRT) during CMP. This technique uses transient COF data induced by a shift in slurry concentration to determine MRT. Variations in consumables as well as sliding velocity, pressure and slurry flow rate can affect the slurry MRT. One study in this dissertation focus on the effect of retaining ring slot designs on the slurry MRT. Another study compares the slurry MRT under same polishing conditions using pads with different groove width. Both studies are conducted on multiple sliding velocity, pressure and slurry flow rate variations to understand the characteristics of consumable designs. The method of measuring MRT during polishing presented in this dissertation can be easily applied in general CMP processes.The subsequent studies focus in the diamond conditioner discs characterization techniques. A newly developed method for determining active diamonds and aggressive diamonds on a diamond conditioner disc under a certain vertical load is elaborated in this dissertation. Later, this technique together with scanning electron microscopy (SEM) imaging is implemented to analyze diamond pullout and fracture in CMP. Five different types of diamond conditioner discs are subjected to a novel accelerated wear test respectively to compare the extent of diamond pullout and fracture under the same conditioning condition

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No description available.

The order of events in the Deacetoxycephalosporin C/Deacetylcephalosporrn C Synthetase (DAOC/DAC Synthetase) catalysed ring expansion of penicillin N to deacetoxycephalosporin C has been investigated by the use of labelled/unlabelled penicillin N mixed competitive kinetic isotope effect experiments, in which the labelled penicillin N substrates were either labelled in the pro <strong>R</strong>- and pro <strong>S</strong>-methyl groups or at C-3. In addition, to assisting in the determination of the position of the first irreversible event in this reaction, deuteration at C-3 gave rise to a bifurcation of the natural biosynthetic pathway which led to enhanced production of the shunt metabolite, (2<strong>R</strong>,3<strong>S</strong>,6<strong>R</strong>,7<strong>R</strong>)-l-aza-3- methyl-3-hydroxy-7-[(5<strong>R</strong>)-5-amino-5-carboxy-pentanamido]-8-oxo-5-thiabicyclo[4.2.0]octane-2-carboxylate. The biosynthetic precursor to the 3<strong>S</strong>-hydroxycepham shunt metabolite has been investigated and the origin of the 3<strong>S</strong>-hydroxyl oxygen atom has been determined by the use of labelling studies with ¹⁸O₂ and shown to be derived from molecular oxygen. ¹³C-labelling studies are described which indicate that the ring expansion process is stereospecific to within the limits of the detection system employed. These experiments confirm earlier investigations but, in addition to improving upon the assessment of the degree of stereospecificity, have shown that the 3<strong>S</strong>- hydroxycepham shunt metabolite is produced with the same stereospecificity as that observed for the usual biosynthetic products, DAOC and DAC. Chapter 5 describes an investigation of the anomalous C-2 deuterium exchange detected in DAOC produced by incubation of di-(²H₃-methyl)-penicillin N with DAOC/DAC synthetase. The preliminary results from this study indicate that initially exchange occurs stereospecifically with the pro <strong>R</strong> C-2 deuterium atom being replaced by a hydrogen atom. The origins of the unusual tripeptides <strong>L</strong>-α-aminoadipyl-<strong>L</strong>-serinyl-<strong>D</strong>-valine (<strong>L</strong>,<strong>L</strong>,<strong>D</strong>-ASV), α-aminoadipyl-serinyl-isodehydrovaline (ASdV) and α-aminoadipyl-cysteinyl- β-hydroxyvaline (AC-[β-OH]-V) isolated from Penicillium chrysogenum and Cephalosporium acremonium, have been examined by the use of variously ¹³C-labelled <strong>L</strong>,<strong>L</strong>,<strong>D</strong>-α-aminoadipyl-cysteinyl-valine (<strong>L</strong>,<strong>L</strong>,<strong>D</strong>-ACV) and <strong>D</strong>,<strong>L</strong>,<strong>D</strong>-α-aminoadipyl- cysteinyl-valine (<strong>D</strong>,<strong>L</strong>,<strong>D</strong>-ACV) tripeptide isotopomers. The initial results obtained from this investigation may be considered as circumstantial evidence that ASdV is formed by the action of IPNS upon <strong>L</strong>,<strong>L</strong>,<strong>D</strong>-ACV. Finally, various substrate analogues have been prepared and evaluated as substrates for the ring expansion and hydroxylation activities of the bifunctional DAOC/DAC synthetase enzyme.

Slope instabilities have been affecting the grade slope of Provincial Trunk Highway 5 near the junction with Provincial Trunk Highway 10 in northwestern Manitoba for over 50 years. In recent years, the instabilities have resulted in significant damage to the highway pavement surface. In 2011, Manitoba Infrastructure and Transportation initiated a geotechnical investigation to gain a better understanding of the failure, identify possible failure mechanisms, and explore various remedial design alternatives in order to stabilize the slope. The site was instrumented with slope inclinometers and vibrating wire piezometers, and monitored over a period of two years. An extensive laboratory testing program was completed to compare the results of direct shear tests and torsional ring shear tests for determining the shear strength of the underlying Cretaceous clay shale. Measured values were compared with values back analyzed using limit equilibrium analysis. A coupled finite element model was used to model the expected excess porewater pressure response, and therefore the stability of the slope, during construction of a stabilization berm. It was subsequently calibrated to agree with the measured porewater pressure responses from the instrumentation. Finally, spring flood conditions were simulated to determine the effect of multiple flash flood events on the stability of the slope.

A ring laser gyroscope (gyro) is an active laser interferometer designed to sense rotation through the Sagnac frequency shift encountered by two beams travelling in opposite directions around a closed path. The classes of devices considered in this thesis are the large and ultra-large ring laser gyros. These instruments are designed for direct measurement of earth rotation rate and find applications in geodesy, geophysics, and tests of physical theories. The research presented in this thesis focuses on the demonstration of new techniques for operating ring laser gyros. The main goal of these techniques has been the correction for variations in the geometry of an ultra-large ring laser gyro, UG-3. This instrument is a 77 m perimeter ultra-large ring laser gyro of heterolithic construction and is the primary instrument used in the experiments presented here. UG-3 has been used to demonstrate measurement of earth strains which have been used to correct for changes in the geometry of the instrument. It has also been used to demonstrate a control technique where the co-rotating beams were alternately offset allowing the number of wavelengths around the perimeter to be counted and a Sagnac rotation signal to be obtained. Among the most important outcomes of this research of interest to the large ring laser gyro community is that we now understand most of the problems that would affect a next generation ring laser gyro. This understanding allows us to choose an operational technique best suited to the measurements being made and thus maximise the scientific potential of the instrument. Additionally, the development of a new standard for data storage and an associated suite of software to acquire, query and analyse ring laser data is expected to improve collaboration with the wider research community. Other research outcomes of more general interest include the analysis of how oscillation of a single mode is established in a high finesse laser cavity. We demonstrate that the ultimate mode of operation can be selected with a ‘seed’ beam of exceptionally low intensity. An interesting related outcome is the demonstration of Sagnac beat frequency measurement during the ring down of a ring cavity, a type of measurement immune to dispersive and flow related frequency shifts.

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No description available.