10 research outputs found

    Design for pre-bond testability in 3D integrated circuits

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    In this dissertation we propose several DFT techniques specific to 3D stacked IC systems. The goal has explicitly been to create techniques that integrate easily with existing IC test systems. Specifically, this means utilizing scan- and wrapper-based techniques, two foundations of the digital IC test industry. First, we describe a general test architecture for 3D ICs. In this architecture, each tier of a 3D design is wrapped in test control logic that both manages tier test pre-bond and integrates the tier into the large test architecture post-bond. We describe a new kind of boundary scan to provide the necessary test control and observation of the partial circuits, and we propose a new design methodology for test hardcore that ensures both pre-bond functionality and post-bond optimality. We present the application of these techniques to the 3D-MAPS test vehicle, which has proven their effectiveness. Second, we extend these DFT techniques to circuit-partitioned designs. We find that boundary scan design is generally sufficient, but that some 3D designs require special DFT treatment. Most importantly, we demonstrate that the functional partitioning inherent in 3D design can potentially decrease the total test cost of verifying a circuit. Third, we present a new CAD algorithm for designing 3D test wrappers. This algorithm co-designs the pre-bond and post-bond wrappers to simultaneously minimize test time and routing cost. On average, our algorithm utilizes over 90% of the wires in both the pre-bond and post-bond wrappers. Finally, we look at the 3D vias themselves to develop a low-cost, high-volume pre-bond test methodology appropriate for production-level test. We describe the shorting probes methodology, wherein large test probes are used to contact multiple small 3D vias. This technique is an all-digital test method that integrates seamlessly into existing test flows. Our experimental results demonstrate two key facts: neither the large capacitance of the probe tips nor the process variation in the 3D vias and the probe tips significantly hinders the testability of the circuits. Taken together, this body of work defines a complete test methodology for testing 3D ICs pre-bond, eliminating one of the key hurdles to the commercialization of 3D technology.PhDCommittee Chair: Lee, Hsien-Hsin; Committee Member: Bakir, Muhannad; Committee Member: Lim, Sung Kyu; Committee Member: Vuduc, Richard; Committee Member: Yalamanchili, Sudhaka

    Shortest Paths and Steiner Trees in VLSI Routing

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    Routing is one of the major steps in very-large-scale integration (VLSI) design. Its task is to find disjoint wire connections between sets of points on a chip, subject to numerous constraints. This problem is solved in a two-stage approach, which consists of so-called global and detailed routing steps. For each set of metal components to be connected, global routing reduces the search space by computing corridors in which detailed routing sequentially determines the desired connections as shortest paths. In this thesis, we present new theoretical results on Steiner trees and shortest paths, the two main mathematical concepts in routing. In the practical part, we give computational results of BonnRoute, a VLSI routing tool developed at the Research Institute for Discrete Mathematics at the University of Bonn. Interconnect signal delays are becoming increasingly important in modern chip designs. Therefore, the length of paths or direct delay measures should be taken into account when constructing rectilinear Steiner trees. We consider the problem of finding a rectilinear Steiner minimum tree (RSMT) that --- as a secondary objective --- minimizes a signal delay related objective. Given a source we derive some structural properties of RSMTs for which the weighted sum of path lengths from the source to the other terminals is minimized. Also, we present an exact algorithm for constructing RSMTs with weighted sum of path lengths as secondary objective, and a heuristic for various secondary objectives. Computational results for industrial designs are presented. We further consider the problem of finding a shortest rectilinear Steiner tree in the plane in the presence of rectilinear obstacles. The Steiner tree is allowed to run over obstacles; however, if it intersects an obstacle, then no connected component of the induced subtree must be longer than a given fixed length. This kind of length restriction is motivated by its application in VLSI routing where a large Steiner tree requires the insertion of repeaters which must not be placed on top of obstacles. We show that there are optimal length-restricted Steiner trees with a special structure. In particular, we prove that a certain graph (called augmented Hanan grid) always contains an optimal solution. Based on this structural result, we give an approximation scheme for the special case that all obstacles are of rectangular shape or are represented by at most a constant number of edges. Turning to the shortest paths problem, we present a new generic framework for Dijkstra's algorithm for finding shortest paths in digraphs with non-negative integral edge lengths. Instead of labeling individual vertices, we label subgraphs which partition the given graph. Much better running times can be achieved if the number of involved subgraphs is small compared to the order of the original graph and the shortest path problems restricted to these subgraphs is computationally easy. As an application we consider the VLSI routing problem, where we need to find millions of shortest paths in partial grid graphs with billions of vertices. Here, the algorithm can be applied twice, once in a coarse abstraction (where the labeled subgraphs are rectangles), and once in a detailed model (where the labeled subgraphs are intervals). Using the result of the first algorithm to speed up the second one via goal-oriented techniques leads to considerably reduced running time. We illustrate this with the routing program BonnRoute on leading-edge industrial chips. Finally, we present computational results of BonnRoute obtained on real-world VLSI chips. BonnRoute fulfills all requirements of modern VLSI routing and has been used by IBM and its customers over many years to produce more than one thousand different chips. To demonstrate the strength of BonnRoute as a state-of-the-art industrial routing tool, we show that it performs excellently on all traditional quality measures such as wire length and number of vias, but also on further criteria of equal importance in the every-day work of the designer

    Human-Robot Collaborations in Industrial Automation

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    Technology is changing the manufacturing world. For example, sensors are being used to track inventories from the manufacturing floor up to a retail shelf or a customer’s door. These types of interconnected systems have been called the fourth industrial revolution, also known as Industry 4.0, and are projected to lower manufacturing costs. As industry moves toward these integrated technologies and lower costs, engineers will need to connect these systems via the Internet of Things (IoT). These engineers will also need to design how these connected systems interact with humans. The focus of this Special Issue is the smart sensors used in these human–robot collaborations

    Study of the impact of lithography techniques and the current fabrication processes on the design rules of tridimensional fabrication technologies

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    Working for the photolithography tool manufacturer leader sometimes gives me the impression of how complex and specific is the sector I am working on. This master thesis topic came with the goal of getting the overall picture of the state-of-the-art: stepping out and trying to get a helicopter view usually helps to understand where a process is in the productive chain, or what other firms and markets are doing to continue improvingUniversidad de sevilla.Máster Universitario en Microelectrónica: Diseño y Aplicaciones de Sistemas Micro/Nanométrico

    Circuit Design

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    Circuit Design = Science + Art! Designers need a skilled "gut feeling" about circuits and related analytical techniques, plus creativity, to solve all problems and to adhere to the specifications, the written and the unwritten ones. You must anticipate a large number of influences, like temperature effects, supply voltages changes, offset voltages, layout parasitics, and numerous kinds of technology variations to end up with a circuit that works. This is challenging for analog, custom-digital, mixed-signal or RF circuits, and often researching new design methods in relevant journals, conference proceedings and design tools unfortunately gives the impression that just a "wild bunch" of "advanced techniques" exist. On the other hand, state-of-the-art tools nowadays indeed offer a good cockpit to steer the design flow, which include clever statistical methods and optimization techniques.Actually, this almost presents a second breakthrough, like the introduction of circuit simulators 40 years ago! Users can now conveniently analyse all the problems (discover, quantify, verify), and even exploit them, for example for optimization purposes. Most designers are caught up on everyday problems, so we fit that "wild bunch" into a systematic approach for variation-aware design, a designer's field guide and more. That is where this book can help! Circuit Design: Anticipate, Analyze, Exploit Variations starts with best-practise manual methods and links them tightly to up-to-date automation algorithms. We provide many tractable examples and explain key techniques you have to know. We then enable you to select and setup suitable methods for each design task - knowing their prerequisites, advantages and, as too often overlooked, their limitations as well. The good thing with computers is that you yourself can often verify amazing things with little effort, and you can use software not only to your direct advantage in solving a specific problem, but also for becoming a better skilled, more experienced engineer. Unfortunately, EDA design environments are not good at all to learn about advanced numerics. So with this book we also provide two apps for learning about statistic and optimization directly with circuit-related examples, and in real-time so without the long simulation times. This helps to develop a healthy statistical gut feeling for circuit design. The book is written for engineers, students in engineering and CAD / methodology experts. Readers should have some background in standard design techniques like entering a design in a schematic capture and simulating it, and also know about major technology aspects

    Circuit Design

    Get PDF
    Circuit Design = Science + Art! Designers need a skilled "gut feeling" about circuits and related analytical techniques, plus creativity, to solve all problems and to adhere to the specifications, the written and the unwritten ones. You must anticipate a large number of influences, like temperature effects, supply voltages changes, offset voltages, layout parasitics, and numerous kinds of technology variations to end up with a circuit that works. This is challenging for analog, custom-digital, mixed-signal or RF circuits, and often researching new design methods in relevant journals, conference proceedings and design tools unfortunately gives the impression that just a "wild bunch" of "advanced techniques" exist. On the other hand, state-of-the-art tools nowadays indeed offer a good cockpit to steer the design flow, which include clever statistical methods and optimization techniques.Actually, this almost presents a second breakthrough, like the introduction of circuit simulators 40 years ago! Users can now conveniently analyse all the problems (discover, quantify, verify), and even exploit them, for example for optimization purposes. Most designers are caught up on everyday problems, so we fit that "wild bunch" into a systematic approach for variation-aware design, a designer's field guide and more. That is where this book can help! Circuit Design: Anticipate, Analyze, Exploit Variations starts with best-practise manual methods and links them tightly to up-to-date automation algorithms. We provide many tractable examples and explain key techniques you have to know. We then enable you to select and setup suitable methods for each design task - knowing their prerequisites, advantages and, as too often overlooked, their limitations as well. The good thing with computers is that you yourself can often verify amazing things with little effort, and you can use software not only to your direct advantage in solving a specific problem, but also for becoming a better skilled, more experienced engineer. Unfortunately, EDA design environments are not good at all to learn about advanced numerics. So with this book we also provide two apps for learning about statistic and optimization directly with circuit-related examples, and in real-time so without the long simulation times. This helps to develop a healthy statistical gut feeling for circuit design. The book is written for engineers, students in engineering and CAD / methodology experts. Readers should have some background in standard design techniques like entering a design in a schematic capture and simulating it, and also know about major technology aspects

    Ensaios sobre mercado de trabalho no Brasil : doenças cardiovasculares, contatos pessoais e empreendedorismo feminino

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    Esta tese é composta por três ensaios sobre o mercado de trabalho brasileiro, cada um correspondendo a um capítulo. O primeiro ensaio identifica se há uma relação entre doenças cardiovasculares e salários no Brasil com base nos dados da Pesquisa Nacional de Saúde 2013. Utilizaram-se os métodos de regressão quantílica incondicional e de decomposição para quantis por meio de funções de influência. Os resultados das regressões indicaram que, para os trabalhadores nos primeiros decis de renda as perdas salariais podem ser significativas. Para os homens, a incidência de doenças cardiovasculares pode reduzir os salários entre 0,90% e 14,80%; para as mulheres, entre 1,20% e 18%. A decomposição mostrou que homens e mulheres valorizam atributos distintos para o cômputo de seus salários e que os cuidados preventivos de saúde ajudam a explicar a menor incidência de doenças cardiovasculares no caso das mulheres. Os homens, por seu turno, apresentam maior demanda por serviços médicos em idades mais avançadas, o que é corroborado pela estimativa negativa da idade sobre o efeito atribuível às características próprias. O segundo ensaio analisa a relação entre (i) o ciclo econômico e o uso de contatos pessoais para obter emprego por meio de um modelo com parâmetros variantes no tempo; e (ii) a relação entre o uso de contatos pessoais para obter emprego e os salários utilizando-se regressão quantílica. Para tanto, foram empregados os microdados da Pesquisa Mensal de Emprego entre 2002 e 2015. As estimativas indicam que o uso de contatos pessoais tornou-se menos anticíclico ao longo do tempo Em geral, eles mostram que há mais evidências de uma relação de mudança lenta entre contatos pessoais e o ciclo econômico ao longo do tempo, em vez de uma quebra repentina e discreta. Observa-se que as diferenças salariais entre trabalhadores que usam contatos pessoais versus trabalhadores que usam outros canais desaparecem. As evidências apontam que os trabalhadores recorrem a contatos pessoais devido à avaliação de características de trabalho não pecuniárias. Por fim, o terceiro ensaio faz uma análise dos retornos do empreendedorismo feminino no Brasil para o período 1992-2015. Para tanto, faz uso dos microdados da Pesquisa Nacional por Amostra de Domicílios e uma análise de regressão que incluiu os efeitos idade, período e coorte. Os resultados implicam que as mudanças que são próprias do perfil etário assumem um papel de destaque na evolução dos rendimentos das mulheres que atuam por conta própria e para as empregadoras informais (aquelas com no máximo cinco empregados). O efeito coorte permitiu um acréscimo de renda às autônomas, por meio da abertura e criação de novas oportunidades a esse segmento de mulheres. Contudo, não apresentou nenhuma correlação com os ganhos monetários das empregadoras, sugerindo a existência de “barreiras” para esse grupo. Os efeitos de curto prazo associados às flutuações econômicas tendem a ser contracíclicos, de forma geral, até 2005 e posteriormente são pró-cíclcos.This thesis is composed of three essays on the Brazilian labor market, each one corresponding to a chapter. The first essay identifies whether there is a relationship between cardiovascular diseases and wages in Brazil based on data from the National Health Survey 2013. The unconditional quantile regression and the quantile-regression based decomposition methods were used, which are based on influence functions. The results of the regressions indicated that, for workers in the first decile of income, wage losses can be significant. For men, the incidence of cardiovascular diseases can reduce wages between 0.90% and 14.80%; for women, between 1.20% and 18%. The decomposition showed that men and women value different attributes for the computation of their wages and that preventive health care helps explain the lower incidence of cardiovascular diseases in the case of women. Men, in turn, have greater demand for medical services at more advanced ages, which is corroborated by the negative age estimate. The second essay analyzes the relationship between (i) business cycle and use of personal contacts to obtain job, and (ii) use of personal contacts to obtain job and wages. To do so, we used the microdata of the Monthly Employment Survey between 2002 and 2015. Time-varying parameter estimates indicate that the relationship between business cycle and use of personal contacts became less countercyclical over time. In general, they show that there is more evidence of a slow changing relationship between personal contacts and the business cycle over time rather than a sudden and discrete one Using quantile regressions, we observed that, controlling for similar observable characteristics, and including unobserved heterogeneity, wage differences between workers using personal contacts versus workers using others channels disappear. The evidences seems to indicate that workers resort to personal contacts because of valuation of non-pecuniary job characteristics. Finally, the third essay analyzes the wage dynamics of women entrepreneurs in Brazil for the 1992-2015 period. To do so, we use the microdata from the National Household Sample Survey. The method consists of a regression analysis that included the effects age, period and cohort. The results suggest that changes in the age play an important role in the evolution of the income of the self-employed and informal employers. The cohort effect allowed an increase in income to the self-employed, through the opening and creation of new opportunities for this segment. However, it did not show any correlation with employers’ monetary gains, suggesting the existence of “barriers” to this group. The short-term effects associated with economic fluctuations tend to be countercyclical, generally up to 2005, and later pro-cyclical

    Life Sciences Program Tasks and Bibliography for FY 1996

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    This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1996. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web page

    References, Appendices & All Parts Merged

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    Includes: Appendix MA: Selected Mathematical Formulas; Appendix CA: Selected Physical Constants; References; EGP merged file (all parts, appendices, and references)https://commons.library.stonybrook.edu/egp/1007/thumbnail.jp
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