Introduction to CMOS VLSI Design

1
Introduction to CMOS VLSI Design

• Adnan Aziz
• The University of Texas at Austin

2
Organization

• Prerequisites logic design, basic computer
  organization
• See sample questions
• Architecture design versus chip design
• Example innovative processor
• Overview of material
• Bottom-up approach, CAD tools
• See syllabus for individual topics
• Course organization
• Website, TA, office hours, HW, projects
• Acknowledgements
• J. Abraham (UT), D. Harris (HMC), R. Tupuri (AMD)

3
Course relevance

• 2007 world wide sales of chips 250B
• Primarily digital
• High-margin business
• Basis for systems
• Most CE graduates work in
• VLSI design Intel, Qualcomm
• System design HP, Cisco
• Software Microsoft, Google

4
Systems and Chips

• This course designing ICs
• Part of a system chips board software
• System companies HP, Cisco
• Chip companies Intel, Qualcomm
• nVidia vs. Hercules
• Example high-end data switch
• Marketing gives range of specs, architect tries
  to meet them
• Off the shelf chips, embedded software
• Why dont we teach system design?

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Course Goals

• Learn to design and analyze state-of-the-art
  digital VLSI chips using CMOS technology
• Employ hierarchical design methods
• Understand design issues at the layout,
  transistor, logic and register-transfer levels
• Use integrated circuit cells as building blocks
• Use commercial design software in the lab
• Understand the complete design flow
• Wont cover architecture, solid-state physics,
  analog design
• Superficial treatment of transistor functioning

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Course Information

• Instructor Adnan Aziz
• [phone], Adnan_at_ece.utexas.edu
• http//www.ece.utexas.edu/adnan
• Course Web Page
• Link from my page
• Book Weste and Harris, CMOS VLSI Design A
  Circuits and Systems Perspective, AW, 3rd edition

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Work in the Course

• Lectures largely from text (not always in
  sequence)
• Homework roughly 6 HWs
• Relatively straightforward review questions
• Laboratory exercises
• Three major exercises dealing with various
  aspects of VLSI design
• Complete each section before the deadline
• Grad students VLSI design project
• Design an IP core, architecture to layout
• Course involves a large amount of work throughout
  the semester

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What Will We Cover?

• Designing chips containing lots of transistors
• How basic components work (transistors, gates,
  flops, memories, adders,
• Complexity management hierarchy and CAD tools
• Key issues
• Creating logical structures from transistors
• Performance analysis and optimization
• Testing functional and manufacturing
• Power consumption, clocking, I/O, etc.

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Exams and Grading

• Two midterm tests in class, open book/notes
  samples will be posted
• Dates for exams in syllabus
• Final exam (360R), project (382M)
• Lab dates in syllabus
• Bonus/penalty for early/late submission
• Weights for homework, exams, project are in
  syllabus
• Relative weights of MT1/2, Lab 1/2/3
  intentionally not specified

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Academic Honesty

• Cheating will not be tolerated
• OK to discuss homework, laboratory exercises with
  classmates, TAs and the instructors
• However write the homework and lab exercises by
  yourself
• We check for cheating, and report incidents

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General Principles

• Technology changes fast gt important to
  understand general principles
• optimization, tradeoffs
• work as part of a group
• leverage existing work programs ,building blocks
• Concepts remain the same
• Example relays -gt tubes -gt bipolar transistors
  -gt MOS transistors

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Types of IC Designs

• IC Designs can be Analog or Digital
• Digital designs can be one of three groups
• Full Custom
• Every transistor designed and laid out by hand
• ASIC (Application-Specific Integrated Circuits)
• Designs synthesized automatically from a
  high-level language description
• Semi-Custom
• Mixture of custom and synthesized modules

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MOS Technology Trends
14
Steps in Design
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System on a Chip
Source ARM
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Laboratory Exercises

• Layout and evaluation of standard cells
• Familiarity with layout, circuit simulation,
  timing
• Design and evaluation of an ALU, performance
  optimization
• Learn schematic design, timing optimization
• Design, synthesis and analysis of a simple
  controller as part of an SoC
• Learn RT-level design, system simulation, logic
  synthesis and place-and-route
• If you already have industrial experience with
  some of these tools, you can substitute lab for
  final project
• Need my approval will expect more from project

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Laboratory Design Tools

• We will use commercial CAD tools
• Cadence, Synopsys, etc.
• Commercial software is powerful, but very complex
• Designers sent to long training classes
• Students will benefit from using the software,
  but we dont have the luxury of long training
• TAs have experience with the software
• Start work early in the lab
• Unavailability of workstations is no excuse for
  late submissions
• Plan designs carefully and save work frequently

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Laboratory Exercise 1
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Laboratory Exercise 2
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Laboratory Exercise 3
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Need for transistors

• Cannot make logic gates with voltage/current
  source, RLC components
• Consider steady state behavior of L and C
• Need a switch something where a (small) signal
  can control the flow of another signal

22
Coherers and Triodes

• Hertz spark gap transmitter, detector
• Verified Maxwells equations
• Not practical Tx/Rx system
• Marconi coherer changes resistance after EM
  pulse, connects to solenoid
• Triode based on Edisons bulbs!
• See Ch. 1, Tom Lee, Design of CMOS RF ICs

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A Brief History of MOS

• Some of the events which led to the microprocessor

Photographs from State of the Art A
photographic history of the integrated circuit,
Augarten, Ticknor Fields, 1983. They can also
be viewed on the Smithsonian web site,
http//smithsonianchips.si.edu/
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Lilienfeld patents
1930 Method and apparatus for controlling
electric currents, U.S. Patent 1,745,175
1933 Device for controlling electric current,
U. S. Patent 1,900,018
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Bell Labs

• 1940 Ohl develops the PN Junction
• 1945 Shockley's laboratory established
• 1947 Bardeen and Brattain create point contact
  transistor (U.S. Patent 2,524,035)

Diagram from patent application
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Bell Labs

• 1951 Shockley develops a junction transistor
  manufacturable in quantity (U.S. Patent
  2,623,105)

Diagram from patent application
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1950s Silicon Valley

• 1950s Shockley in Silicon Valley
• 1955 Noyce joins Shockley Laboratories
• 1954 The first transistor radio
• 1957 Noyce leaves Shockley Labs to form
  Fairchild with Jean Hoerni and Gordon Moore
• 1958 Hoerni invents technique for diffusing
  impurities into Si to build planar transistors
  using a SiO2 insulator
• 1959 Noyce develops first true IC using planar
  transistors, back-to-back PN junctions for
  isolation, diode-isolated Si resistors and SiO2
  insulation with evaporated metal wiring on top

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The Integrated Circuit

• 1959 Jack Kilby, working at TI, dreams up the
  idea of a monolithic integrated circuit
• Components connected by hand-soldered wires and
  isolated by shaping, PN-diodes used as
  resistors (U.S. Patent 3,138,743)

Diagram from patent application
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Integrated Circuits

• 1961 TI and Fairchild introduce the first logic
  ICs (50 in quantity)
• 1962 RCA develops the first MOS transistor

RCA 16-transistor MOSFET IC
Fairchild bipolar RTL Flip-Flop
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Computer-Aided Design

• 1967 Fairchild develops the Micromosaic IC
  using CAD
• Final Al layer of interconnect could be
  customized for different applications
• 1968 Noyce, Moore leave Fairchild, start Intel

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RAMs

• 1970 Fairchild introduces 256-bit Static RAMs
• 1970 Intel starts selling1K-bit Dynamic RAMs

Fairchild 4100 256-bit SRAM
Intel 1103 1K-bit DRAM
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The Microprocessor

• 1971 Intel introduces the 4004
• General purpose programmable computer instead of
  custom chip for Japanese calculator company