Heurísticas bioinspiradas para el problema de Floorplanning 3D térmico de dispositivos MPSoCs

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Informática, Departamento de Arquitectura de Computadores y Automática, leída el 20-06-2013Depto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaTRUEunpu

Investigation into yield and reliability enhancement of TSV-based three-dimensional integration circuits

Three dimensional integrated circuits (3D ICs) have been acknowledged as a promising technology to overcome the interconnect delay bottleneck brought by continuous CMOS scaling. Recent research shows that through-silicon-vias (TSVs), which act as vertical links between layers, pose yield and reliability challenges for 3D design. This thesis presents three original contributions.The first contribution presents a grouping-based technique to improve the yield of 3D ICs under manufacturing TSV defects, where regular and redundant TSVs are partitioned into groups. In each group, signals can select good TSVs using rerouting multiplexers avoiding defective TSVs. Grouping ratio (regular to redundant TSVs in one group) has an impact on yield and hardware overhead. Mathematical probabilistic models are presented for yield analysis under the influence of independent and clustering defect distributions. Simulation results using MATLAB show that for a given number of TSVs and TSV failure rate, careful selection of grouping ratio results in achieving 100% yield at minimal hardware cost (number of multiplexers and redundant TSVs) in comparison to a design that does not exploit TSV grouping ratios. The second contribution presents an efficient online fault tolerance technique based on redundant TSVs, to detect TSV manufacturing defects and address thermal-induced reliability issue. The proposed technique accounts for both fault detection and recovery in the presence of three TSV defects: voids, delamination between TSV and landing pad, and TSV short-to-substrate. Simulations using HSPICE and ModelSim are carried out to validate fault detection and recovery. Results show that regular and redundant TSVs can be divided into groups to minimise area overhead without affecting the fault tolerance capability of the technique. Synthesis results using 130-nm design library show that 100% repair capability can be achieved with low area overhead (4% for the best case). The last contribution proposes a technique with joint consideration of temperature mitigation and fault tolerance without introducing additional redundant TSVs. This is achieved by reusing spare TSVs that are frequently deployed for improving yield and reliability in 3D ICs. The proposed technique consists of two steps: TSV determination step, which is for achieving optimal partition between regular and spare TSVs into groups; The second step is TSV placement, where temperature mitigation is targeted while optimizing total wirelength and routing difference. Simulation results show that using the proposed technique, 100% repair capability is achieved across all (five) benchmarks with an average temperature reduction of 75.2? (34.1%) (best case is 99.8? (58.5%)), while increasing wirelength by a small amount

TSV placement optimization for liquid cooled 3D-ICs with emerging NVMs

Three dimensional integrated circuits (3D-ICs) are a promising solution to the performance bottleneck in planar integrated circuits. One of the salient features of 3D-ICs is their ability to integrate heterogeneous technologies such as emerging non-volatile memories (NVMs) in a single chip. However, thermal management in 3D-ICs is a significant challenge, owing to the high heat flux (~ 250 W/cm2). Several research groups have focused either on run-time or design-time mechanisms to reduce the heat flux and did not consider 3D-ICs with heterogeneous stacks. The goal of this work is to achieve a balanced thermal gradient in 3D-ICs, while reducing the peak temperatures. In this research, placement algorithms for design-time optimization and choice of appropriate cooling mechanisms for run-time modulation of temperature are proposed. Specifically, an architectural framework which introduce weight-based simulated annealing (WSA) algorithm for thermal-aware placement of through silicon vias (TSVs) with inter-tier liquid cooling is proposed for design-time. In addition, integrating a dedicated stack of emerging NVMs such as RRAM, PCRAM and STTRAM, a run-time simulation framework is developed to analyze the thermal and performance impact of these NVMs in 3D-MPSoCs with inter-tier liquid cooling. Experimental results of WSA algorithm implemented on MCNC91 and GSRC benchmarks demonstrate up to 11 K reduction in the average temperature across the 3D-IC chip. In addition, power density arrangement in WSA improved the uniformity by 5%. Furthermore, simulation results of PARSEC benchmarks with NVM L2 cache demonstrates a temperature reduction of 12.5 K (RRAM) compared to SRAM in 3D-ICs. Especially, RRAM has proved to be thermally efficient replacement for SRAM with 34% lower energy delay product (EDP) and 9.7 K average temperature reduction

Thermal-aware 3D Microarchitectural Floorplanning

Next generation deep submicron processor design will need to take into consideration many performance limiting factors. Flip flops are inserted in order to prevent global wire delay from becoming nonlinear, enabling deeper pipelines and higher clock frequency. The move to 3D ICs will also likely be used to further shorten wirelength. This will cause thermal issues to become a major bottleneck to performance improvement. In this paper we propose a floorplanning algorithm which takes into consideration both thermal issues and profile weighted wirelength using mathematical programming. Our profile-driven objective improves performance by 20% over wirelength-driven. While the thermal-driven objective improves temperature by 24% on average over the profile-driven case

Interconnect Planning for Physical Design of 3D Integrated Circuits

Vertical stacking—based on modern manufacturing and integration technologies—of multiple 2D chips enables three-dimensional integrated circuits (3D ICs). This exploitation of the third dimension is generally accepted for aiming at higher packing densities, heterogeneous integration, shorter interconnects, reduced power consumption, increased data bandwidth, and realizing highly-parallel systems in one device. However, the commercial acceptance of 3D ICs is currently behind its expectations, mainly due to challenges regarding manufacturing and integration technologies as well as design automation. This work addresses three selected, practically relevant design challenges: (i) increasing the constrained reusability of proven, reliable 2D intellectual property blocks, (ii) planning different types of (comparatively large) through-silicon vias with focus on their impact on design quality, as well as (iii) structural planning of massively-parallel, 3D-IC-specific interconnect structures during 3D floorplanning. A key concept of this work is to account for interconnect structures and their properties during early design phases in order to support effective and high-quality 3D-IC-design flows. To tackle the above listed challenges, modular design-flow extensions and methodologies have been developed. Experimental investigations reveal the effectiveness and efficiency of the proposed techniques, and provide findings on 3D integration with particular focus on interconnect structures. We suggest consideration of these findings when formulating guidelines for successful 3D-IC design automation.:1 Introduction 1.1 The 3D Integration Approach for Electronic Circuits 1.2 Technologies for 3D Integrated Circuits 1.3 Design Approaches for 3D Integrated Circuits 2 State of the Art in Design Automation for 3D Integrated Circuits 2.1 Thermal Management 2.2 Partitioning and Floorplanning 2.3 Placement and Routing 2.4 Power and Clock Delivery 2.5 Design Challenges 3 Research Objectives 4 Planning Through-Silicon Via Islands for Block-Level Design Reuse 4.1 Problems for Design Reuse in 3D Integrated Circuits 4.2 Connecting Blocks Using Through-Silicon Via Islands 4.2.1 Problem Formulation and Methodology Overview 4.2.2 Net Clustering 4.2.3 Insertion of Through-Silicon Via Islands 4.2.4 Deadspace Insertion and Redistribution 4.3 Experimental Investigation 4.3.1 Wirelength Estimation 4.3.2 Configuration 4.3.3 Results and Discussion 4.4 Summary and Conclusions 5 Planning Through-Silicon Vias for Design Optimization 5.1 Deadspace Requirements for Optimized Planning of Through-Silicon Vias 5.2 Multiobjective Design Optimization of 3D Integrated Circuits 5.2.1 Methodology Overview and Configuration 5.2.2 Techniques for Deadspace Optimization 5.2.3 Design-Quality Analysis 5.2.4 Planning Different Types of Through-Silicon Vias 5.3 Experimental Investigation 5.3.1 Configuration 5.3.2 Results and Discussion 5.4 Summary and Conclusions 6 3D Floorplanning for Structural Planning of Massive Interconnects 6.1 Block Alignment for Interconnects Planning in 3D Integrated Circuits 6.2 Corner Block List Extended for Block Alignment 6.2.1 Alignment Encoding 6.2.2 Layout Generation: Block Placement and Alignment 6.3 3D Floorplanning Methodology 6.3.1 Optimization Criteria and Phases and Related Cost Models 6.3.2 Fast Thermal Analysis 6.3.3 Layout Operations 6.3.4 Adaptive Optimization Schedule 6.4 Experimental Investigation 6.4.1 Configuration 6.4.2 Results and Discussion 6.5 Summary and Conclusions 7 Research Summary, Conclusions, and Outlook Dissertation Theses Notation Glossary BibliographyDreidimensional integrierte Schaltkreise (3D-ICs) beruhen auf neuartigen Herstellungs- und Integrationstechnologien, wobei vor allem “klassische” 2D-ICs vertikal zu einem neuartigen 3D-System gestapelt werden. Dieser Ansatz zur Erschließung der dritten Dimension im Schaltkreisentwurf ist nach Expertenmeinung dazu geeignet, höhere Integrationsdichten zu erreichen, heterogene Integration zu realisieren, kürzere Verdrahtungswege zu ermöglichen, Leistungsaufnahmen zu reduzieren, Datenübertragungsraten zu erhöhen, sowie hoch-parallele Systeme in einer Baugruppe umzusetzen. Aufgrund von technologischen und entwurfsmethodischen Schwierigkeiten bleibt jedoch bisher die kommerzielle Anwendung von 3D-ICs deutlich hinter den Erwartungen zurück. In dieser Arbeit werden drei ausgewählte, praktisch relevante Problemstellungen der Entwurfsautomatisierung von 3D-ICs bearbeitet: (i) die Verbesserung der (eingeschränkten) Wiederverwendbarkeit von zuverlässigen 2D-Intellectual-Property-Blöcken, (ii) die komplexe Planung von verschiedenartigen, verhältnismäßig großen Through-Silicion Vias unter Beachtung ihres Einflusses auf die Entwurfsqualität, und (iii) die strukturelle Einbindung von massiv-parallelen, 3D-IC-spezifischen Verbindungsstrukturen während der Floorplanning-Phase. Das Ziel dieser Arbeit besteht darin, Verbindungsstrukturen mit deren wesentlichen Eigenschaften bereits in den frühen Phasen des Entwurfsprozesses zu berücksichtigen. Dies begünstigt einen qualitativ hochwertigen Entwurf von 3D-ICs. Die in dieser Arbeit vorgestellten modularen Entwurfsprozess-Erweiterungen bzw. -Methodiken dienen zur effizienten Lösung der oben genannten Problemstellungen. Experimentelle Untersuchungen bestätigen die Wirksamkeit sowie die Effektivität der erarbeiten Methoden. Darüber hinaus liefern sie praktische Erkenntnisse bezüglich der Anwendung von 3D-ICs und der Planung deren Verbindungsstrukturen. Diese Erkenntnisse sind zur Ableitung von Richtlinien für den erfolgreichen Entwurf von 3D-ICs dienlich.:1 Introduction 1.1 The 3D Integration Approach for Electronic Circuits 1.2 Technologies for 3D Integrated Circuits 1.3 Design Approaches for 3D Integrated Circuits 2 State of the Art in Design Automation for 3D Integrated Circuits 2.1 Thermal Management 2.2 Partitioning and Floorplanning 2.3 Placement and Routing 2.4 Power and Clock Delivery 2.5 Design Challenges 3 Research Objectives 4 Planning Through-Silicon Via Islands for Block-Level Design Reuse 4.1 Problems for Design Reuse in 3D Integrated Circuits 4.2 Connecting Blocks Using Through-Silicon Via Islands 4.2.1 Problem Formulation and Methodology Overview 4.2.2 Net Clustering 4.2.3 Insertion of Through-Silicon Via Islands 4.2.4 Deadspace Insertion and Redistribution 4.3 Experimental Investigation 4.3.1 Wirelength Estimation 4.3.2 Configuration 4.3.3 Results and Discussion 4.4 Summary and Conclusions 5 Planning Through-Silicon Vias for Design Optimization 5.1 Deadspace Requirements for Optimized Planning of Through-Silicon Vias 5.2 Multiobjective Design Optimization of 3D Integrated Circuits 5.2.1 Methodology Overview and Configuration 5.2.2 Techniques for Deadspace Optimization 5.2.3 Design-Quality Analysis 5.2.4 Planning Different Types of Through-Silicon Vias 5.3 Experimental Investigation 5.3.1 Configuration 5.3.2 Results and Discussion 5.4 Summary and Conclusions 6 3D Floorplanning for Structural Planning of Massive Interconnects 6.1 Block Alignment for Interconnects Planning in 3D Integrated Circuits 6.2 Corner Block List Extended for Block Alignment 6.2.1 Alignment Encoding 6.2.2 Layout Generation: Block Placement and Alignment 6.3 3D Floorplanning Methodology 6.3.1 Optimization Criteria and Phases and Related Cost Models 6.3.2 Fast Thermal Analysis 6.3.3 Layout Operations 6.3.4 Adaptive Optimization Schedule 6.4 Experimental Investigation 6.4.1 Configuration 6.4.2 Results and Discussion 6.5 Summary and Conclusions 7 Research Summary, Conclusions, and Outlook Dissertation Theses Notation Glossary Bibliograph

Through-silicon-via-aware prediction and physical design for multi-granularity 3D integrated circuits

The main objective of this research is to predict the wirelength, area, delay, and power of multi-granularity three-dimensional integrated circuits (3D ICs), to develop physical design methodologies and algorithms for the design of multi-granularity 3D ICs, and to investigate the impact of through-silicon vias (TSVs) on the quality of 3D ICs. This dissertation supports these objectives by addressing six research topics. The first pertains to analytical models that predict the interconnects of multi-granularity 3D ICs, and the second focuses on the development of analytical models of the capacitive coupling of TSVs. The third and the fourth topics present design methodologies and algorithms for the design of gate- and block-level 3D ICs, and the fifth topic pertains to the impact of TSVs on the quality of 3D ICs. The final topic addresses topography variation in 3D ICs. The first section of this dissertation presents TSV-aware interconnect prediction models for multi-granularity 3D ICs. As previous interconnect prediction models for 3D ICs did not take TSV area into account, they were not capable of predicting many important characteristics of 3D ICs related to TSVs. This section will present several previous interconnect prediction models that have been improved so that the area occupied by TSVs is taken into account. The new models show numerous important predictions such as the existence of the number of TSVs minimizing wirelength. The second section presents fast estimation of capacitive coupling of TSVs and wires. Since TSV-to-TSV and TSV-to-wire coupling capacitance is dependent on their relative locations, fast estimation of the coupling capacitance of a TSV is essential for the timing optimization of 3D ICs. Simulation results show that the analytical models presented in this section are sufficiently accurate for use at various design steps that require the computation of TSV capacitance. The third and fourth sections present design methodologies and algorithms for gate- and block-level 3D ICs. One of the biggest differences in the design of 2D and 3D ICs is that the latter requires TSV insertion. Since no widely-accepted design methodology designates when, where, and how TSVs are inserted, this work develops and presents several design methodologies for gate- and block-level 3D ICs and physical design algorithms supporting them. Simulation results based on GDSII-level layouts validate the design methodologies and present evidence of their effectiveness. The fifth section explores the impact of TSVs on the quality of 3D ICs. As TSVs become smaller, devices are shrinking, too. Since the relative size of TSVs and devices is more critical to the quality of 3D ICs than the absolute size of TSVs and devices, TSVs and devices should be taken into account in the study of the impact of TSVs on the quality of 3D ICs. In this section, current and future TSVs and devices are combined to produce 3D IC layouts and the impact of TSVs on the quality of 3D ICs is investigated. The final section investigates topography variation in 3D ICs. Since landing pads fabricated in the bottommost metal layer are attached to TSVs, they are larger than TSVs, so they could result in serious topography variation. Therefore, topography variation, especially in the bottommost metal layer, is investigated and two layout optimization techniques are applied to a global placement algorithm that minimizes the topography variation of the bottommost metal layer of 3D ICs.PhDCommittee Chair: Lim, Sung Kyu; Committee Member: Bakir, Muhannad; Committee Member: Kim, Hyesoon; Committee Member: Lee, Hsien-Hsin Sean; Committee Member: Mukhopadhyay, Saiba

CAD methodologies for low power and reliable 3D ICs

The main objective of this dissertation is to explore and develop computer-aided-design (CAD) methodologies and optimization techniques for reliability, timing performance, and power consumption of through-silicon-via(TSV)-based and monolithic 3D IC designs. The 3D IC technology is a promising answer to the device scaling and interconnect problems that industry faces today. Yet, since multiple dies are stacked vertically in 3D ICs, new problems arise such as thermal, power delivery, and so on. New physical design methodologies and optimization techniques should be developed to address the problems and exploit the design freedom in 3D ICs. Towards the objective, this dissertation includes four research projects. The first project is on the co-optimization of traditional design metrics and reliability metrics for 3D ICs. It is well known that heat removal and power delivery are two major reliability concerns in 3D ICs. To alleviate thermal problem, two possible solutions have been proposed: thermal-through-silicon-vias (T-TSVs) and micro-fluidic-channel (MFC) based cooling. For power delivery, a complex power distribution network is required to deliver currents reliably to all parts of the 3D IC while suppressing the power supply noise to an acceptable level. However, these thermal and power networks pose major challenges in signal routability and congestion. In this project, a co-optimization methodology for signal, power, and thermal interconnects in 3D ICs is presented. The goal of the proposed approach is to improve signal, thermal, and power noise metrics and to provide fast and accurate design space explorations for early design stages. The second project is a study on 3D IC partition. For a 3D IC, the target circuit needs to be partitioned into multiple parts then mapped onto the dies. The partition style impacts design quality such as footprint, wirelength, timing, and so on. In this project, the design methodologies of 3D ICs with different partition styles are demonstrated. For the LEON3 multi-core microprocessor, three partitioning styles are compared: core-level, block-level, and gate-level. The design methodologies for such partitioning styles and their implications on the physical layout are discussed. Then, to perform timing optimizations for 3D ICs, two timing constraint generation methods are demonstrated that lead to different design quality. The third project is on the buffer insertion for timing optimization of 3D ICs. For high performance 3D ICs, it is crucial to perform thorough timing optimizations. Among timing optimization techniques, buffer insertion is known to be the most effective way. The TSVs have a large parasitic capacitance that increases the signal slew and the delay on the downstream. In this project, a slew-aware buffer insertion algorithm is developed that handles full 3D nets and considers TSV parasitics and slew effects on delay. Compared with the well-known van Ginneken algorithm and a commercial tool, the proposed algorithm finds buffering solutions with lower delay values and acceptable runtime overhead. The last project is on the ultra-high-density logic designs for monolithic 3D ICs. The nano-scale 3D interconnects available in monolithic 3D IC technology enable ultra-high-density device integration at the individual transistor-level. The benefits and challenges of monolithic 3D integration technology for logic designs are investigated. First, a 3D standard cell library for transistor-level monolithic 3D ICs is built and their timing and power behavior are characterized. Then, various interconnect options for monolithic 3D ICs that improve design quality are explored. Next, timing-closed, full-chip GDSII layouts are built and iso-performance power comparisons with 2D IC designs are performed. Important design metrics such as area, wirelength, timing, and power consumption are compared among transistor-level monolithic 3D, gate-level monolithic 3D, TSV-based 3D, and traditional 2D designs.PhDCommittee Chair: Lim, Sung Kyu; Committee Member: Bakir, Muhannad; Committee Member: Kim, Hyesoon; Committee Member: Lee, Hsien-Hsin; Committee Member: Mukhopadhyay, Saiba

TSVを考慮した3次元積層プロセッサ向けフロアプランナの提案とマルチコアプロセッサの配置設計

近年半導体技術の進歩により3次元積層技術が開発され、半導体チップの更なる性能向上が期待されている。 3次元積層実装を行うことによってトランジスタ数あたりのチップ面積（フットプリント）を減少させることが出来、さらにはモジュール（一定の機能をもったひとまとまりの回路）同士の幾何学的な距離が短くなり，平面配置に比べて配線長を短縮することが出来る。さらに、積層間の結線を行う際にチップ外に配線を通して結線するワイヤボンディングに代わり、積層内を貫通する電極であるTSVを用いる事で積層間配線長を短縮できるようになった。3次元積層技術の利点としてチップ面積の減少とそれに伴う歩留まりの向上、モジュール間配線の減少による高速化と消費電力の減少、バンド幅の増加、異なるプロセスの混在など数多くの利点が挙げられ、TSVによる柔軟な配線はこれらをさらに促進する。一方で3次元積層技術の問題点は、設計の難化、製造コストの増大、熱密度の増加が挙げられる。柔軟な層間配線を可能とするTSVだが、通常配線に比べれば100?1000倍程度の大きさとなる。更に総配線長はTSVがどこに配置されるかによって大きく変化する。しかし、従来の手法ではモジュール位置が優先され，TSVの配置が最適化されない。そこで本論文では複数のTSVをまとめて扱い，TSV配置を準最適化する探索配置アルゴリズムを提案する。我々の手法ではTSVを配置するための場所を仮想的なモジュール、「TSVモジュール」として他のモジュールと同様に探索アルゴリズムに従って準最適化する。提案システムの評価ではシングルコアプロセッサ、マルチコアプロセッサについてフロアプランを取得した。 これらの評価を行い、TSVモジュールを導入することでいままでより配線が向上したフロアプランを得ることが出来た。これはシングルコアだけではなくマルチコアでも同様なことが言えた。また、従来のシーケンスペアではホワイトスペースが出来ないような位置にTSVモジュールが存在することで、本来の手法では配置されないような場所にもTSVを配置するのに適した場所が存在する事がわかった。電気通信大学201