4 research outputs found

    Switching Noise in 3D Power Distribution Networks: An Overview

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    Through Silicon Via์˜ Coupling Noise๋ฅผ ์–ต์ œํ•˜๋Š” ๋ฐ˜์ „ ์ „ํ•˜์ธต์„ ์ด์šฉํ•œ Guard Ring ์ œ์ž‘ ๋ฐ ๋ถ„์„

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    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์ „๊ธฐยท์ปดํ“จํ„ฐ๊ณตํ•™๋ถ€, 2015. 8. ์ด์ข…ํ˜ธ.As technology shrinks, the implementation of high-density chip with a two-dimensional (2-D) planar architecture is becoming more difficult due to the limitation of lithography process. To overcome such scale-down limitations, a three-dimensional (3-D) package has been investigated. Among the various 3-D package technologies, a through silicon via (TSV) is a promising technology in which several chips are stacked vertically and electrically. This 3-D package can enhance the memory capacity, and implement a system with different functional chips. Although TSVs offer many advantages when used to achieve a high-density package, they also have several disadvantages, such as coupling noise. A high-frequency signal applied to a TSV induces noise in transistors near the TSV due to electrical coupling. Another issue is that copper (Cu) which is used as a conducting material of the TSV generates trap density caused by large diffusivity of Cu atoms. In this dissertation, we propose a new guard ring which consists of a shallow n+ region, a deep n-well, and an inversion layer formed along the interface between the oxide surrounding the TSV (TSV oxide) and the p-substrate. The proposed guard ring utilizes an inversion charge induced by a positive oxide charge located at the interface of the TSV oxide. We characterize quantitatively a TSV with a guard ring which is used to reduce the coupling noise from the TSV by utilizing an inversion layer as a shield layer. It is shown that a transient current due to the coupling is clearly reduced when the proposed guard ring is used. The proposed method is compared with a conventional guard ring method in terms of the drain current of a victim nMOSFET. The effective depth of the inversion layer with the signal frequency is also characterized. It is demonstrated that the high-frequency response of the guard ring can be modeled as an RC equivalent circuit. The proposed guard ring is effective in shielding the coupling noise and can be fabricated easily by modifying the ion implantation mask layer. A TSV conducting material requires high conductivity for low power consumption and high-speed operation. Cu is widely used as a TSV conducting material, but Cu atoms diffuse to the adjacent silicon substrate and transistors easily and generate traps during a low temperature annealing process. It is very important to suppress Cu diffusion and to devise a proper method to measure how many Cu atoms diffuse due to annealing. However, the characteristics of traps induced by Cu diffusion in a TSV are not easily measured because TSVs are typically located some distance away from the silicon surface, reaching a depth of tens of micrometers. For this reason, the deep part of a TSV cannot be measured. We suggest a measurement method which can be used to evaluate the trap density generated by Cu diffusion through the use of the proposed guard ring and analyze Cu diffusion as a parameter of the thickness of the barrier metal.Contents Abstract 1 Contents 4 Chapter 1 Introduction 6 1.1 BACKGROUND OF TSV 6 1.2 MOTIVATION FOR THE RESEARCH 14 Chapter 2 Structure of the guard ring and the TSV 15 2.1 INTRODUCTION 15 2.2 PROCESS FLOW OF FABRICATING TSV AND GUARD RING 20 2.3 STRUCTURE OF THE TSV AND THE PROPOSED GUARD RING 24 Chapter 3 Characteristics of the proposed guard ring 27 3.1 INTRODUCTION 27 3.2 JUNCTION CHARACTERISTICS OF THE PROPOSED GUARD RING 28 3.3 C-V CHARACTERISTICS OF THE PROPOSED GUARD RING 31 Chapter 4 Effective method to analyze the trap density 40 4.1 INTRODUCTION 40 4.2 CHARACTERISTICS OF CU DIFFUSION WITH BARRIER METAL THICKNESS 42 4.3 EFFECT OF CU DIFFUSION ENHANCED BY ADDITIONAL ANNEALING 53 Chapter 5 Shielding ability of the proposed guard ring 65 5.1 INTRODUCTION 65 5.2 SHIELDING ABILITY OF THE PROPOSED GUARD RING 69 5.3 EFFECTIVENESS OF THE PROPOSED GUARD RING 75 5.4 CHARACTERISTICS OF THE PROPOSED GUARD RING BY RC MODELING 86 Conclusions 91 Bibliography 93 Abstract in Korean 98Docto

    VLSI Design

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    This book provides some recent advances in design nanometer VLSI chips. The selected topics try to present some open problems and challenges with important topics ranging from design tools, new post-silicon devices, GPU-based parallel computing, emerging 3D integration, and antenna design. The book consists of two parts, with chapters such as: VLSI design for multi-sensor smart systems on a chip, Three-dimensional integrated circuits design for thousand-core processors, Parallel symbolic analysis of large analog circuits on GPU platforms, Algorithms for CAD tools VLSI design, A multilevel memetic algorithm for large SAT-encoded problems, etc
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