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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.
71

Processing, Reliability And Integration Issues In Chemical Mechanical Planarization

Zantye, Parshuram B 15 July 2005 (has links)
Global planarization is one of the major demands of the semiconductor industry. Chemical mechanical polishing (CMP) is the planarization method of choice use to achieve the required stringent tolerances essential for successful fabrication of next generation Integrated Circuits (IC). The predominant reason for CMP defects is the shear and normal stresses during polishing to which the material is subjected. Understanding the process of CMP and factor that contribute to overall stress addition during polishing requires an approach that encompasses all the four major categories of variables, namely: a) machine parameters, b) material properties, c) polishing pad characteristics, and d) polishing slurry performance. In this research, we studied the utilized in-situ technique involving acoustic emission (AE) signal monitoring and coefficient of friction (COF) monitoring using a CETRTM Bench Top CMP Tester to evaluate the impact of variation in machine parameters on the CMP process. The mechanical and tribological properties of different candidate materials have been evaluated bring potential challenges in their integration to the fore. The study also involves destructive and non destructive testing of polishing pads performed for characterization and optimization of polishing pad architecture. Finally, the investigation concludes proposing novel nanoparticle CMP slurry which has a predominant chemical component in its polishing mechanism. It was found that the decrease in the mechanical shear and normal loading by: a) operating the process in the low stress regime, b) using potential materials that are mechanically stronger, c) using polishing pads with lesser variation in specific gravity and with a surface that is has its mechanical properties fine tuned to those of the wafer, and d) deploying polishing slurry with a significant chemical component mechanical removal, are some of the approaches that can be employed to meet the future challenges of the CMP process and reduce the defect associated with it.
72

Evaluation des performances isolantes de couches de SIOCH poreuses et de polymères destinés aux technologies d'intégration innovantes

Dubois, Christelle 13 May 2011 (has links) (PDF)
L'objectif de ce travail de thèse a été d'évaluer, à partir d'outils de caractérisation électrique (spectroscopie d'impédance basse fréquence et courants thermo-stimulés), l'impact des étapes de polissage mécanochimique (CMP) et de recuits thermiques sur les propriétés diélectriques de matériaux utilisés pour les dernières générations de circuits intégrés. Une première partie est focalisée sur le matériau SiOCH poreux déposé par voie chimique " en phase vapeur " assisté par plasma (PECVD) suivant une approche porogène (p=26%, d=2nm et er=2,5). Son intégration dans les technologies 45nm nécessite l'utilisation d'un procédé de 'CMP directe' qui induit une dégradation des propriétés isolantes attribuée à l'adsorption de surfactants et de molécules d'eau. L'analyse diélectrique sur une large gamme de fréquence (10-1Hz- 105Hz) et de température (-120°C -200°C) a mis en évidence plusieurs mécanismes de relaxation diélectrique et de conduction liés à la présence de molécules nanoconfinées (eau et porogène) dans les pores du matériau. L'étude de ces mécanismes a permis d'illustrer le phénomène de reprise en eau du SiOCH poreux ainsi que d'évaluer la capacité de traitements thermiques à en restaurer les performances. Une seconde partie concerne l'étude d'une résine époxy chargée avec des nanoparticules de silice, utilisée en tant que 'wafer level underfill' dans les technologies d'intégration 3D. Les analyses en spectroscopie d'impédance ont montré que l'ajout de nanoparticules de silice s'accompagne d'une élévation de la température de transition vitreuse et de la permittivité diélectrique, ainsi que d'une diminution de la conductivité basse fréquence. L'autre contribution majeure des mesures diélectriques a été de montrer qu'un refroidissement trop rapide de la résine à l'issue de la réticulation était responsable d'une contrainte interne qui pourra occasionner des problèmes de fiabilité pour l'application.
73

Dynamic, In-Situ Pressure Measurements during CMP

Osorno, Andres 26 September 2005 (has links)
A rotational setup for measuring interfacial fluid pressure and temperature was successfully constructed. Interfacial fluid measurements were performed with various slurries, slurry flow rates, and pad topographies. It was experimentally determined that the pad topography has the biggest effect in pressure and temperature distribution. This was also confirmed by tilt experiments ran in a rotational environment. For all cases, the edge high conditioned pad displayed the most changes during the experiments. For an edge high conditioned pad, the fluid pressure was found to be mostly subambient reaching levels of up to 42 kPa at the center of the fixture, and dissipating towards the edges. The pressure maps appear to be almost center symmetric. The pressure was found to be positive during the first second of contact, and rapidly turn subambient. The Subambient pressures stabilize after about 5 seconds, and their suction force was found to slow the rotating platen significantly. Suction forces were confirmed by displacement observed during the tilt experiments. The fixtures center was sucked down into the pad up to 20 m, and tends to tilt towards the leading edge. Interfacial temperatures were also found to vary with pad geometry. The edge-high conditioned pad exhibited changes of up to 4 C, concentrated at the center. The relative position and shape of these temperature rises matches the results observed in the pressure experiments. Temperature takes a longer time to reach equilibrium, up to 30 seconds in most measurements.
74

Numerical heat transfer during partially-confined, confined, and free liquid jet impingement with rotation and chemical mechanical planarization process modeling

Lallave-Cortes, Jorge C 01 June 2009 (has links)
No description available.
75

Chemical Mechanical Planarization and Old Italian Violins

Philipossian, Ara, Sampurno, Yasa, Peckler, Lauren 18 January 2018 (has links)
Previous studies have shown that spectral analysis based on force data can elucidate fundamental physical phenomena during chemical mechanical planarization (CMP). While it has not been literally described elsewhere, such analysis was partly motivated by modern violinmakers and physicists studying Old Italian violins, who were trying to discover spectral relations to sound quality. In this paper, we draw parallels between violins and CMP as far as functionality and spectral characteristics are concerned. Inspired by the de facto standard of violin testing via hammer strikes on the base edge of a violin's bridge, we introduce for the first time, a mobility plot for the polisher by striking the wafer carrier head of a CMP polisher with a hammer. Results show three independent peaks that can indeed be attributed to the polisher's natural resonance. Extending our study to an actual CMP process, similar to hammered and bowed violin tests, at lower frequencies the hammered and polished mobility peaks are somewhat aligned. At higher frequencies, peak alignment becomes less obvious and the peaks become more isolated and defined in the case of the polished wafer spectrum. Lastly, we introduce another parameter from violin testing known as directivity, , which in our case, we define as the ratio of shear force variance to normal force variance acquired during CMP. Results shows that under identical polishing conditions, increases with the polishing removal rate.
76

Porous Ultra Low-k Material Integration Through An Extended Dual Damascene Approach: Pre-/ Post-CMP Curing Comparison

Calvo, Jesús, Koch, Johannes, Thrun, Xaver, Seidel, Robert, Uhlig, Benjamin 22 July 2016 (has links)
Integration of dielectrics with increased porosity is required to reduce the capacitance of interconnects. However, the conventional dual damascene integration approach is causing negative effects to these materials avoiding their immediate implementation. A post-CMP curing approach could solve some of these issues. However, materials with porogens being stable at temperatures of the barrier-seed deposition process are not common, hindering this approach. Here, we report on an extended dual-damascene integration approach which permits post-CMP curing.
77

Využití elektrostimulace ke snížení spasticity u pacienta po CMP / Utilizing of electrical stimulation for decreasing of spasticity in stroke patient

Ustinova, Darya January 2021 (has links)
1 Abstract Electrical stimulation by coupled impulses according to Hufschmidt was created with the primary goal of reducing spasticity. However, there are currently few studies that confirm or refute the effect of this type of electrical stimulation in reducing spasticity. The aim of this diploma thesis was to determine the effect of electrostimulation according to Hufschmidt on the reduction of biceps brachii spasticity in patients after stroke. In addition, the effect of electrical stimulation on increasing the active range of movement of the antagonist of the examined muscle and on the active function of the spastic limb was investigated. For these purposes, a non-randomized controlled pilot study was created, which involved a total of 16 probands, 8 - in the therapeutic group, 8 - in the control group. Five-step clinical assessment in spastic paresis according to Gracies were used for the examination. In the therapeutic group, electrostimulation took place 3 times a week, a total of 8 times. The intragroup difference was evaluated using the Friedman and Wilcoxon paired tests, the intergroup difference was subsequently evaluated using the Mann-Whitney U test. The significance level p = 0.05 applies to all tests. The measured values show that Hufschmidt's electrical stimulation has a positive effect on...
78

Improving Energy Efficiency of Network-on-Chips Using Emerging Wireless Technology and Router Optimizations

DiTomaso, Dominic F. 25 July 2012 (has links)
No description available.
79

Možnosti funkčního hodnocení stavu pacientů po prodělané akutní CMP v ČR / Possibilites of functional evaluation of patients after acute cerbral palsy in ČR

Cvrčková, Iveta January 2013 (has links)
Title: Possibilities of functional Evaluation of Patients after acute cerebral Palsy in Czech Republic Objectives: The main objective of this study was to describe the problems of functional assessment of patiens after stroke. Another objektive was to determine and compare the properties ofthe most commonly used functional measures designed for stroke,in our country. Methods: This work is theoretical - research work, which is the theoretical part of the period from September 2012 to June 2013 when retrieving data from literature sources using advanced targeted keywords and thein hotkey in databases based on EBM. The practical part of the study consisted of a questionnaire, which was using the questionnaire survey gathered data needed to evaluace the clinical utility, in the period from May 2013 to July 2013. After obtaining the necessary data from both theoretical and practical part of this data was evaluated and analyzed according to the standard metodology for the evaluation of functional measures for spinal patiens (Chapman, J.R. et al, 2007) and the results of the individual measures were mutually compared. Results: In the theoretical part of the available resources found high objectivity of the free evaluated measures, the measure Barthel Index and the Functional independence measure received...
80

Exploring coordinated software and hardware support for hardware resource allocation

Figueiredo Boneti, Carlos Santieri de 04 September 2009 (has links)
Multithreaded processors are now common in the industry as they offer high performance at a low cost. Traditionally, in such processors, the assignation of hardware resources between the multiple threads is done implicitly, by the hardware policies. However, a new class of multithreaded hardware allows the explicit allocation of resources to be controlled or biased by the software. Currently, there is little or no coordination between the allocation of resources done by the hardware and the prioritization of tasks done by the software.This thesis targets to narrow the gap between the software and the hardware, with respect to the hardware resource allocation, by proposing a new explicit resource allocation hardware mechanism and novel schedulers that use the currently available hardware resource allocation mechanisms.It approaches the problem in two different types of computing systems: on the high performance computing domain, we characterize the first processor to present a mechanism that allows the software to bias the allocation hardware resources, the IBM POWER5. In addition, we propose the use of hardware resource allocation as a way to balance high performance computing applications. Finally, we propose two new scheduling mechanisms that are able to transparently and successfully balance applications in real systems using the hardware resource allocation. On the soft real-time domain, we propose a hardware extension to the existing explicit resource allocation hardware and, in addition, two software schedulers that use the explicit allocation hardware to improve the schedulability of tasks in a soft real-time system.In this thesis, we demonstrate that system performance improves by making the software aware of the mechanisms to control the amount of resources given to each running thread. In particular, for the high performance computing domain, we show that it is possible to decrease the execution time of MPI applications biasing the hardware resource assignation between threads. In addition, we show that it is possible to decrease the number of missed deadlines when scheduling tasks in a soft real-time SMT system.

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