Introduction to CMOS
VLSI Design
Adnan Aziz
The University of Texas at Austin
Introduction
CMOS VLSI Design
Slide 1
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)
Introduction
CMOS VLSI Design
Slide 2
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
Introduction
CMOS VLSI Design
Slide 3
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 don’t we teach system design?
Introduction
CMOS VLSI Design
Slide 4
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
– Won’t cover architecture, solid-state physics, analog design
– Superficial treatment of transistor functioning
Introduction
CMOS VLSI Design
Slide 5
Course Information
 Instructor: Adnan Aziz
– (512) 465-9774, Adnan@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
Introduction
CMOS VLSI Design
Slide 6
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
Introduction
CMOS VLSI Design
Slide 7
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.
Introduction
CMOS VLSI Design
Slide 8
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
Introduction
CMOS VLSI Design
Slide 9
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
Introduction
CMOS VLSI Design
Slide 10
General Principles
 Technology changes fast => 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 -> tubes -> bipolar transistors ->
MOS transistors
Introduction
CMOS VLSI Design
Slide 11
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
Introduction
CMOS VLSI Design
Slide 12
MOS Technology Trends
Introduction
CMOS VLSI Design
Slide 13
Steps in Design
Designer
Tasks
Define Overall Chip
Architect
C/RTL Model
Tools
Text Editor
C Compiler
Initial Floorplan
Behavioral Simulation
Logic
Designer
Logic Simulation
Synthesis
Datapath Schematics
RTL Simulator
Synthesis Tools
Timing Analyzer
Power Estimator
Cell Libraries
Circuit
Designer
Circuit Schematics
Circuit Simulation
Megacell Blocks
Schematic Editor
Circuit Simulator
Router
Layout and Floorplan
Physical
Designer
Place and Route
Parasitics Extraction
DRC/LVS/ERC
Introduction
CMOS VLSI Design
Place/Route Tools
Physical Design
and Evaluation
Tools
Slide 14
System on a Chip
Source: ARM
Introduction
CMOS VLSI Design
Slide 15
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
Introduction
CMOS VLSI Design
Slide 16
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 don’t 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
Introduction
CMOS VLSI Design
Slide 17
Laboratory Exercise 1
Schematics
(Cadence)
Library
Symbol
LVS
DRC
Layout
(Cadence)
Introduction
Functional model
(Simulation)
Extraction
(Cadence)
Characterization
SPICE
CMOS VLSI Design
Footprint (APR)
Timing model
Slide 18
Laboratory Exercise 2
Library
Schematics
(Cadence)
Functional
Verification
VerilogXL
Data Path Block
Library
LVS
DRC
Layout
(Cadence)
Introduction
Extraction
(Cadence)
Static Timing
Analysis
(Synopsys)
CMOS VLSI Design
Schematic
Layout
Slide 19
Laboratory Exercise 3
Verilog
RTL model
Synthesis
(Synopsis)
APR
(Cadence)
Extraction
(Cadence)
Static Timing Analysis
(Synopsys)
Control Block
Formal
Verification
(Verplex)
Introduction
Netlist
Layout
CMOS VLSI Design
Slide 20
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
Introduction
CMOS VLSI Design
Slide 21
Coherers and Triodes
 Hertz: spark gap transmitter, detector
– Verified Maxwell’s equations
– Not practical Tx/Rx system
 Marconi: “coherer” changes resistance after EM
pulse, connects to solenoid
 Triode: based on Edison’s bulbs!
• See Ch. 1, Tom Lee, “Design of CMOS RF ICs”
Introduction
CMOS VLSI Design
Slide 22
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/
Introduction
CMOS VLSI Design
Slide 23
Lilienfeld patents
1930: “Method and
apparatus for controlling
electric currents”, U.S.
Patent 1,745,175
Introduction
1933: “Device for controlling
electric current”, U. S. Patent
1,900,018
CMOS VLSI Design
Slide 24
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
Introduction
CMOS VLSI Design
Slide 25
Bell Labs
 1951: Shockley develops a junction transistor
manufacturable in quantity (U.S. Patent 2,623,105)
Diagram from patent application
Introduction
CMOS VLSI Design
Slide 26
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
Introduction
CMOS VLSI Design
Slide 27
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
Introduction
CMOS VLSI Design
Slide 28
Integrated Circuits
 1961: TI and Fairchild introduce the first logic
ICs ($50 in quantity)
 1962: RCA develops the first MOS transistor
Fairchild bipolar RTL Flip-Flop
Introduction
RCA 16-transistor MOSFET IC
CMOS VLSI Design
Slide 29
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
Introduction
CMOS VLSI Design
Slide 30
RAMs
 1970: Fairchild introduces 256-bit Static RAMs
 1970: Intel starts selling1K-bit Dynamic RAMs
Fairchild 4100 256-bit SRAM
Introduction
CMOS VLSI Design
Intel 1103 1K-bit DRAM
Slide 31
The Microprocessor
 1971: Intel introduces the 4004
– General purpose programmable computer instead of
custom chip for Japanese calculator company
Introduction
CMOS VLSI Design
Slide 32