|Litho Process Corner Identification using Test Structures|
Lithographic process variations, such as changes in focus, exposure, resist thickness introduce distortions to line shapes on a wafer. Large distortions may lead to line open and bridge faults. Locations of such defects vary with lithographic process corner. Based on lithographic simulation, it is easily verified that for a given layout, changing one or more of the process parameters shifts the defect location. Thus, if the lithographic process corner of a die is known, test patterns can be better targeted for both hard and parametric defects. In this talk, we will present design of control structures such that preliminary testing of these structures can uniquely identify the manufacturing process corner. If the manufacturing process corner is known, we can easily attain highest possible fault coverage for lithography related defects during manufacturing test. Parametric defects such as delay defects are notorious to test because such defects may affect paths that are subcritical under nominal conditions and not ordinarily targeted for test. Adoption of the proposed approach can easily flag such paths for delay tests.
Dr. Sandip Kundu, University of Massachusetts, Amherst
|What Can We Learn about Quality from the Hubble Space Telescope?|
Technology has come to one of many cliffs. Too often, massively complex constructions are brought down by an event that is lost in the minutia. Case in point, the initial failure of the Hubble Space Telescope. Through a series of what appeared to be defensive steps, a complete failure was inadvertently created. What has been clearly taught over the last 30 years is that it is not effective to perform your contribution perfectly; you must defend your contribution from potential attack. You must chose to climb to the top of the cliff that appears at the beginning of the project to a higher ground, not be swept to your demise over the cliff at the end of the path that is not yet seen in the rush to complete. But, which of the cliffs that you see ahead, or to the side, do you chose to climb and how? This talk will point to how to choose where to put extra effort and it is left to you to determine how best to make the ascent.
Dr. Kevin Thompson, Synopsys
|Transistor Evolution from 90nm to 15nm|
Analysis of the transistor evolution happening in the industry over the last several technology nodes reveals that despite the on-schedule chip area scaling, there has been a crisis in transistor scaling. In leading edge technology, the critical transistor size did not change all the way from 90nm to 20nm nodes. The underlying physical mechanisms explain why it is happening and point to the upcoming changes in transistor architecture that will enable transistor shrinking to resume. The scaling crisis is responsible for the slower than anticipated variability increase and for the stress engineering taking over the driver’s seat in the performance race. A change in the transistor architecture at 15nm node will change the balance of major variability mechanisms and some of the lithography requirements and design rules. It will also open the door for introduction of non-silicon transistors built on top of a silicon wafer. Comparative analysis of a planar bulk MOSFET with FDSOI MOSFET and a FinFET shows their pros and cons and suggest their likely roles in the future.
Dr. Victor Moroz, Synopsys
|Why Design Must Change: Rethinking Digital Design |
Design is so expensive we can’t afford to spend it on creating a single chip. Working out the interactions in a complex design is challenging and costs a lot of money, even when we do it well. The key is to leverage this work over a broader range of chips – we need to design chip-generators and not chips. One creates a virtual programmable chip (the generator) that is MUCH more flexible than any real chip (it has no resource constraints) and the application designer (the new chip designer) then configures this system to produce a customized chip at low cost. While there are many hard problems that need to be addressed to make this work, none seem insurmountable. I will present some recent examples from my group which indicate the promise of this approach - including improving the energy efficiency of a H.264 encoder by 200x, and validating a chip generator.
Mark Horowitz, Stanford University
|Random Variability in Transistors and SRAM: Measurement, Analysis, and Improvement|
We have fabricated and measured large scale device-matrix-array (DMA) TEG of 1M transistors and 16k SRAM cells. The origins of random variability in transistors have been analyzed and its suppression methods have been pursued. In the first half of the talk, the origins of random variability in Vth and drain current are discussed based on measured data and simulation. In the second half, the relationship between measured static noise margin (SNM) and Vth of individual transistor in SRAM cells is discussed using DMA SRAM TEG.
Dr. Toshiro Hiramoto, University of Tokyo
|Geographic Access Engine for Layout Design: Part I|
The presented GA Engine is bin array based and can solve numerous rectilinear geometry computation in O(N) time, including geometric operations like reverse, merge, enlarge, shrink, contour, smooth and maximize-area. All operations are based on a fact: shapes decomposed in same direction can be merged in O(N) time with the help of constant time RQ. To process 100+ million shapes, the GA Engine needs to take both algorithm and SW engineering challenges. Without getting into programming details, some SW architecture concerns are also addressed in this presentation. As an example, we'll show how to construct an O(N) rectilinear polygon engine from this GA Engine.
Mingfu Gong and Yanyan He; Synopsys Inc.
|Third Revolution: The Search for Scalable Code-Based Design|
Over the last 25 years, there have been two major revolutions in how we do digital design: the move to language/synthesis based design (starting in 1986) and design reuse (starting around 1996). We are well overdue for a third revolution. Current design methods are not meeting the needs dictated by the complexity and size of today’s SoC designs, much less the designs of the future.
This talk will describe the current candidates for the next revolution in digital design: high level synthesis, chip generators, and radical extensions to the synthesizable subset of current RTL languages. It will also describe how the economics of SoC design and manufacturing, as well as the economics of EDA, will affect and possibly de-rail the third revolution.
Mike Keating, Synopsys Inc.
|Rapid3D 20X Performance Improvement|
Due to changing product requirements, our group recently rewrote the Raphael-NXT random walk capacitance extraction product. Surprisingly good results were obtained, a 20X improvement in speed, a 3X reduction in memory and 6X reduction in lines of code at the same level of accuracy. These improvements were due to both changes in the numeric algorithms and changes in software architecture goals. After an introduction to random walk capacitance extraction the presentation will discuss how problem areas were identified and the performance improvement was made possible.
Dr. Greg Rollins, Synopsys
|Why Johnny Can’t Code |
Software and Functional Verification are the two largest and fastest-growing components of chip design cost. They are also the aspects of chip design that involve large – or even huge – amounts of code. The languages used in chip design – SystemVerilog, C++ - allow the creation of very complex functionality, and semiconductor technology and EDA tools allow us to implement these complex designs. But our approach to code-based design has not enabled us to manage this complexity effectively. In particular, newly graduated students do not have the tools or the theoretical grounding to develop code-based designs that will meet the needs of the chips of the next decade – when we may well see chips with 1 trillion transistors. This talk will outline the nature of the challenges of code-based design and suggest a path for managing the functional complexity demanded – and enabled – by tomorrow’s SoC designs.
Mike Keating, Synopsys Inc.
|Creating 3D Specific Systems|
3D stacking and integration with TSVs can provide significant system advantages in terms of power, scale, cost and performance. This talk will cover what we have learned at NCSU over the past five years putting together CAD flows for 3DIC design and designing multiple 3DIC chips in the Lincoln Labs and Tezzaron 3D processes. Issues to be covered in detail include 3D motivation, system engineering, floorplanning and partitioning, thermal analaysis and CAD flow.
Prof. Paul Franzon, North Carolina State University
|The Synergy Between Logic Synthesis and Formal Verification|
Our research group has been working on logic synthesis with forays into formal verification for several decades. As a result, we have become increasingly aware of the similarity between these two lines of research, resulting in a synergistic approach, which is our main research focus these days. For example, formal verification systems often use And-Invertor-Graphs (AIGs). Verification experts developed these and came up with very fast methods to reduce the AIG representation for use in verification engines. Recently, these computations have been extended to work in synthesis, resulting in improved quality and scalability, as exemplified by its successful adoption in several FPGA synthesis tools. Investigation of the commonalities between logic synthesis and formal verification led us to develop a new CAD tool, ABC, which is both a synthesis and verification tool. ABC is a public domain system in development at Berkeley. It has become popular with academic institutions as well as industrial companies. In the talk, ABC will be overviewed and some of the synthesis techniques borrowed from verification will be described.
Prof. Robert K. Brayton and Prof. Alan Mishchenko, University of California Berkeley
|An Analytical Study on the Role of Thermal TSVs in a 3DIC Chip Stack|
This paper analyzes the effectiveness of the use of thermal TSVs in lowering the overall average temperature of a 3D IC vertical stack as well as the impact and significance of thermal TSV count on the vertical and lateral thermal gradients in the stack for a given set of initial boundary conditions. A set of simulations were carried out using a 3DIC compact thermal model simulator on a multi-tier multi-die 3DIC design to access these effects of thermal TSVs.
Min Ni, Qing Su, Zongwu Tang, and Jamil Kawa, Synopsys Inc.
|TSV Stress Management|
This tutorial addresses the multi-physics challenges associated with TSV based 3D IC technology that need to be considered including mechanical and thermal stresses experienced inter-die and intra-die and the impact of those stresses on performance and on reliability.
Jamil Kawa, Synopsys Inc.
|A Revisit to the Primal-Dual Based Clock Skew|
Clock skew scheduling is a useful sequential circuit optimization method. The run time efficiency of this problem becomes crucial if it must be repeated iteratively in a higher level optimization. The widely recognized Burns' algorithm proposed to solve this problem suffers from high runtime complexity, which makes it unsuitable to be deployed in iterative optimization loops. This algorithm is based on the general concept of primal-dual optimization. In this paper, we demonstrate that a more efficient approach to the clock skew scheduling problem can be developed by designing a new algorithm using the same primal-dual optimization concept. The basic idea of the algorithm is to avoid creating new admissible graph and recalculating theta values for each iteration of the primal-dual optimization. The asymptotic runtime efficiency of our algorithm is of O(|V||E|+|V|log|V|), which is improved from O(|V|^2|E|) thanks to the heap data structure used in our proposed algorithm. The experimental results show that our algorithm is on average 95 times faster than Burns' implementation. In a best case, we can observe as much as 189 times speedup.
Min Ni¹ and Seda Ogrenci Memik², Synopsys Inc.¹, Northwestern University²
|A Scalable Methodology for Analog and Mixed-Signal Verification|
Traditional verification approaches for analog & mixed-signal designs do not scale well with increasing design complexity and product functionality. Full chip verification in the presence of analog components can be very slow, tedious, and difficult to maintain. In this tutorial, we focus on a scalable methodology for analog & mixed-signal verification that leverages advanced techniques used for verification of digital designs. Behavioral modeling using Verilog-AMS and SystemVerilog constructs will be presented. This tutorial addresses the several challenging issues that present road blocks for verification closure, and presents a methodology that promotes reuse and easy to maintain verification environment. Various strategies will be explored, for both top-down and bottom-up approaches, to develop a framework that can be shared across design teams, design stages, and product cycles.
Shyam Rapaka and Tapan Halder, Synopsys Inc.
|Is Built-In Logic Redundancy Ready for Prime Time|
With each new process generation, it becomes ever more challenging to maintain high yields of integrated circuits. Progressively lower yields potentially undermine the profits of semiconductor companies across all industry segments. Embedding redundant logic into designs can improve product yields, but is this economically viable for most systems-on-chip? This paper attempts to answer this fundamental question. After describing an example architecture for built-in logic redundancy (BILR), we examine precisely how the BILR design and test parameters affect the area overhead, test execution time and yield of the redundant system. After conveying the cost model, we present analysis results showing that redundancy could be cost-effective, depending on a number of cost infrastructure variables that include the parameters of the BILR system itself.
Chris Allsup, Synopsys Inc.
|Test of the Future: Some Thoughts for the Next Decade|
Over the last 40 years, test has moved from being a fab tool to being a design tool, and has become an integral part of the design flow. This move has allowed better (QOR), cheaper (COR), and faster (TTR) test. As the vanguards of the semiconductor industry approach the 32-nanometer node and start planning the jump to the 22-nanometer node, a number of fundamental challenges are emerging, which force a thorough rethinking of the role of test. Like drugs, which often have counter-indications and side effects, even nanometer design and manufacturing are not immune to drawbacks. This requires that test assume an equal station to nanometer design and manufacturing, is accounted for by them, and inter-operates thoroughly with them. Both implementation and yield management tools may feed test with the design and manufacturing-related information it needs to keep problems manageable, while guaranteeing the desired quality and cost of results. At the same time, test can feed implementation and manufacturing with a great deal of information, which can help identify, locate, fix and/or prevent yield issues. In this keynote, Dr. Domic will describe how design, manufacturing, and test can join forces, and “collaborate” to battle the nanometer challenges.
Dr. Antun Domic, Synopsys Inc.
|The Role of Simulation in Photovoltaics: From Solar Cells to Arrays|
The photovoltaic industry is undergoing a transformational evolution as it expands production capacity and deployments to meet the growing need for green alternative sources of electricity production. Two of the primary drivers for the industry are the reduction in the cost of the solar cells and modules, and the improvement of the performance, particularly the conversion efficiency. To meet these challenges, new materials, manufacturing technologies and cell designs are being investigated. To support this development, simulation provides key insights into the physics of solar cell operation, enabling engineers to fully explore the range of design alternatives. At the module and system level, behavioral models allow engineers to examine design trade-offs which impact system performance. This talk reviews the current status of simulation in the development of photovoltaic technologies, from solar cell design to system performance, and provides an outlook for future work.
Ricardo Borges, Kurt Mueller, and Nelson Braga, Synopsys Inc.
|Overview of Technology Trends and 22nm Technology Node|
The ongoing technology scaling provides improved area, cost, speed, leakage, and power. We look at the technology innovations that are necessary to go from the current 32nm node to the next (22nm) node and beyond. For the last 40 years, semiconductor industry has been driven by planar MOSFETs, which are expected to be still manufactured at 22nm node, but will be initially complemented, and eventually overtaken by alternative transistor architectures. We review the alternative transistor architectures and the differences in their inherent variability mechanisms. Special attention is devoted to the analysis of performance boosting high-k/metal gate and stress engineering technologies and how they can be used to leverage either speed or leakage or both. In addition to conventional layout scaling that doubles transistor density for each subsequent technology node, 3D chip integration using through-silicon vias (TSV) is expected to be in high volume production within the next two years. We present TSV process flow and TSV impact on the adjacent circuit.
Dr. Victor Moroz, Synopsys
|Relay Technology and Circuit Design for Energy-Efficient Electronics|
Transistor scaling has yielded continual improvements in integrated-circuit performance and cost per function over the past several decades, ushering in the Information Age. Continued transistor scaling will not be as straightforward in the future as it has been in the past, however, due to fundamental limits leading to increased power consumption. In this seminar, we will discuss recent developments, research, and challenges in micro-relay technology and circuits that aim to overcome the CMOS power crisis and usher in the Age of Ambient Intelligence.
Professor Tsu-Jae King Liu & Professor Elad Alon, UC Berkeley
|Through-Silicon-Via Based 3D IC Research Activities at the GTCAD Laboratory|
This talk provides an overview of various 3D IC research projects being conducted at the Georgia Tech Computer-Aided Design (GTCAD) Laboratory. With the support of the US National Security Agency (NSA), we are currently building a many-core 3D processor with stacked memory (arguably the first in academia). Our 3D processor features 64 cores and SRAM memory banks that are interconnected with high-density through-silicon-vias (TSV).
Sung Kyu Lim, Georgia Institute of Technology
|Model Reduction of Large-Scale Systems: An Overview and Some New Results |
Direct numerical simulation has become one of few available means for the systematic study of physical or artificial processes for which experiments are expensive and/or time-consuming to perform. But without the aid of systematic strategies for reducing model complexity, the burdens of complex geometries, multi-physics, and operating environments coupled with an ever increasing appetite for accuracy and model fidelity, would likely render simulation an ineffective tool. In this talk we will give an overview of projection methods for model reduction and discuss some recent results.
Thanos Antoulas, Rice University
|Design & Verification of Low Power SoCs|
The areas chosen for this tutorial include wireless, automotive, IP, and EDA flows. A general overview of low power design and verification challenges for SoC designers will set the context for each of the application areas.
Yatin Trivedi¹, Gary Delp², John Biggs³, Srikanth Jadcherla¹,
Synopsys Inc.¹, LSI², ARM³
|Addressing Verification Challenges in the Next Decade|
Verification consumes continue to consume the majority of the implementation effort of any new design. In an era of billion-gate chips, ultra-low power and consumer-driven economics, how can we continue to deliver working designs at an acceptable cost?
Janick Bergeron, Synopsys Inc.