DigitalIntegratedCircuits

(83-313)

SemesterB,2015-16

Lecturer:AdamTeman

TAs:Itamar Levi,RobertGiterman1

Lecture 1:

Introduction

WhatwillwedointhisCourse?

2

InDigitalElectronicCircuits,welearnedthebasicsof

buildingadigitalgateandgottoknowanumberof

methodsindigitalcircuitdesign.

Inthiscoursewewillstepupalevel,including:

Connectingthetheoretical(schematic)implementationofthe

circuittoitsphysical(layout)implementation.

Learnaboutparasitics thatareinherenttointegratedcircuit

design.

Considerthetrade-offsinusingdifferentarchitecturesand

designalternatives.

Learnhowto“put-it-all-together”towardscompilingaVLSI

chip.

WhatwillwedointhisCourse?

3

ThiscoursedealswiththeCircuitLevel andGateLevel

designofdigitalcomponents.

Togetabetter“hands-on”understanding,wewilluse

CadenceVirtuoso to:

Compileourcircuits.

Simulatecircuitoperation.

Understandphysicalimplementationandprocessvariations.

Uponcompletionofthiscourse,youwillhaveagood

understandingofwhat’shappening“underneaththe

HDL”.

There’sNoFreeLunch!

Understanding,designingand

optimizingthetrade-offs

between:

Performance

Power

Cost

Reliability

1

3 42

Whatwillwelearntoday?

5

Course

LogisticsDesign

Abstraction

andStyles

Howachipis

born

Costofan

Integrated

Circuit

6

Course Administration

• Lecturer: Dr. Adam Teman

adam.teman@biu.ac.il

Lecture: Monday 09:00-12:00. Class 249

One break in the middle!

Office Hrs: Monday 14:00-15:00. Office 413

• Teaching Assistants:

Itamar Levi itamar.levi@biu.ac.il

Office Hrs: Wednesday 1630-1730

Robert Giterman robert.giterma@biu.ac.il

Office Hrs: Wednesday 1200-1300

Labs: TBD

• Course Web Page: Moodle

Whoarewe?

7

EnICS – EmergingNanoscaled

IntegratedCircuitsandSystemsLabs

TheEnICS Family

8

Grading

9

§ Quizzes:

§ Intro Quiz: 8%

§ 3 Quizzes: 45%

§ 6 Homeworks: 42%

§ Participation and Evaluation: 5%

Labs

10

Labsare2hourslong.

Labsaredoneingroupsoftwo.

Eachgrouphasalabeveryotherweek.

SignupforLab1TODAY!

Itamar andRobertwillpassaroundasignupsheet.

Exactgroupingscanbesetinthelab,butsincetheystartonWednesday,

youwillneedtosignuptoday.

DuringthefirstlabitismandatorytosignanNDA.

LabSchedule

11

Week Homework Lab

1-2 SPICE WritingaSPICEnetlist.

ControllingSPICEwithascript.

3-4 MOSFETS BasicMOSFET Parameters

5-6 AutomaticLayout

inVirtuoso

CustomFloorplanning,Placementand

RoutinginVirtuoso

7-8 Advanced

MOSFETS

AdvancedDeviceParameters

9-10 Verilog/Verilog-A MixedSignal Simulation

11-12 SystemDesign Designing asmallmemory

ReadingMaterial

12

MainBook:

Rabaey, et al., “Digital Integrated Circuits: A Design Perspective”, 2nd Edition, 2003.Highly recommended: UC Berkeley EE141 – lectures online (most recent from 2012)

Butmostlectureswillhaveareadinglist.

Inordertogetabetterunderstanding,itishighly

advisedtousethesereferences!

CourseSyllabus

13

Lecture 1: Introduction Lecture 2: Process and LayoutLecture 3: The NanoScaled MOSFETLecture 4: ScalingLecture 5: InterconnectLecture 6: MemoriesLecture 7: Sequential LogicLecture 8: ArithmeticLecture 9: Back to the Future

IntroQuiz:14/3

Quiz1:11/4

Quiz2:30/5

Quiz3:20/6

NoLectureson:18/4(Pesach),25/4(Pesach),23/5(ISCAS),13/5(Shavuot)

2

3 41

Whatwillwelearntoday?

14

Design

Abstraction

andStyles

Course

Logistics

Howachipis

born

Costofan

Integrated

Circuit

Primer:WhatisanICChip?

15

Primer:WhatisanICChip?

16

Example:dynOR

17

cpu_dca

control

cgu

cgu_mux

DynOR-light arch. v2.1

same high voltage for all modules, except for the cpus

in cpu_dca and cpu_ref,which have a separate low

voltage and level shifters

cpu

tms_err dca_ctrl

mem_data

SPREG 1024x32

membus membus

clockbox

mor1kx

mif_muxclk_ext_i

mem_instr

SPREG 1024x32

cpu_refcpu

mem_data

SPREG 1024x32

membus membus

clockbox

mor1kx

mem_instr

SPREG 1024x32

debug_mon

mem_edram

conf_ctrl

reg. filereset_sync

...

rst_n_ext_i

moduleresets

serialif

master

...

clk_cgu

sdat_i

eflags, notifiers, ...

sdat_o

clockbox cdca:

ext

cgu

CG

CG

CG

cpu

mem

dca

clockbox cref:

ext

cgu

CG

CG

cpu

mem

scan chain 0

scan chain 1

gp_i[1:0]

gp_o[21:0]

io_mux_ctrl

io_mux_i

tms_rst_gen

cpu_input_sync

debug signals:divided clock,eflags, notifiers,cgu periods,im addr.,edram if

cpu_input_sync sregsreg

DevelopinganASIC

18

ChipDesign Fab/Foundry

CAD/EDA

SiliconValleyorSiliconWadi?

19www.siliconvalley.co.il

Digitalvs.Analog

20

q DigitaldesignenablesAbstraction!

q Abstractionisonlyavailablewhenthereisseparation

(i.e.nofeedback)betweenblocks.

q In otherwords– noisesuppression.

q Thisisverydifficult withAnalogdesign.

q Inaddition,DigitaldesignisScalable,whereasthe

parasiticeffectsintroducedbyscalingcauselimitations

toanalogscaling.

DeviceLevelAbstraction

21

FabricationPlantsorFoundriessupplya

ProcessDesignKit (PDK).

ThePDKincludes:

Devices(Transistors,Resistors,Capacitors,Diodes)

Layers

Rules

Various“Flavors”ofPDKsareavailable,e.g.:

GeneralPurpose/HighSpeed/LowPower

RF/ImageSensor

Flash/DRAM

VariousnumberofMetalInterconnectLayers Device Level

CircuitLevelAbstraction

22

UsingthedevicessuppliedinthePDK,Schematics aredrawn.

Simulators,suchasSPICE,areusedtotestandoptimizethe

circuits.

Variousparameters(calledCDFparameters)canbemodifiedto

optimizetheschematic,e.g.:

LengthandWidthoftransistors.

NumberofFingers.

CapacitancesandResistances.

CircuitsaredrawnwithaLayoutEditor and

parasitics areextractedforaccuratesimulation.

22

Device Level

CircuitLevel

GateLevelAbstraction

23

Drawncircuitsareabstractedintoa

blackboxforuseasgates.

Thesegatesaredefinedbyeasyto

usecharacteristics,suchas:

BooleanFunctionality.

Interface(i.e.pins orports).

Delayandpowerconsumption.

Inputandoutputcapacitance.

Sizeandgeometry.

Onceagateisabstracted,itcanbe

usedbyhigherleveltools,suchasHDLs.

23

Device Level

CircuitLevel

GateLevel

ModuleLevelAbstraction

24

Gatesandotherlowlevelcircuitsareconnected

togetherintomodules(adders,memories,etc.).

Thesearetestedforfunctionalityandareabstracted

forsystemintegration.

Analogmodulesareabstractedfromcircuitlevel.

Digitalmodulesandfullsystemsarecomprisedwith

HDLs,instantiatinggatesandmodules.

EDAtoolsareusedtoverifyfunctionalityatalldepths

ofhierarchy.

24

Device Level

CircuitLevel

GateLevel

ModuleLevel

SystemLevelAbstraction

25

Architecturaldesigndefineshighlevelabstractionsto

buildasystem.

Thisabstractionleveldefines:

Registers

InstructionSets

ControlBlocks

Buses

etc.

SystemsareimplementedwithHDLsand

functionalityisverifiedwithlogicalverification.

Systemaredefinedtocomplywithstandards

andimplementprotocols. Device Level

CircuitLevel

GateLevel

ModuleLevel

SystemLevel

HigherLevelAbstraction

26

Programmerswritecodeinahighlevel

programminglanguage (C,Java,Perl,etc.)

ACompiler translatesthecodeintoanAssembly

language.

Compilerstrytooptimizetheinstructionsaccordingtothe

actualarchitecturetheyarecompilingto.

AnAssembler translatestheAssemblyinto

MachineLanguage (i.e.0’sand1’s).

Device Level

CircuitLevel

GateLevel

ModuleLevel

SystemLevel

DesignAbstractionLevels

27

n+n+S

GD

+

DEVICE

CIRCUIT

GATE

MODULE

SYSTEM

Whoactuallydoesthiswork?

28

VLSIDesignStyles

29

Duetotimeandcostconstraints,veryfewteamsand/or

companiesdevelopproductsfromdevicelevelthrough

tosystemlevel.

VariousDesignStyles areavailabletoshortenthetime-

to-market anddevelopmentcost.

Trade-offs aretakenintoconsideration,asabstractions

areusuallydesignedgenerically andthereforecome

withsomeoverhead.

CMOSTechnology

30

31

VLSIDesignStyles– FullCustom

32

FullCustomDesign

Theoriginaldesignstyle.

Everythingisdoneat

transistorlevel

Rarelyusedindigitaldesign

Highcost

But,givessignificantgainin

performance.

Analogdesignsmostly

INTEL4004 www.arstechnica.com

VLSIDesignStyles– StandardCells

Standard-cellsbaseddesign

(ASIC- ApplicationSpecificIntegratedCircuit)

HDLsaremappedtoLibraries

33

VLSIDesignStyles– GateArray

GateArrayDesignorStructuredASIC

Designimplementationisdonewithmetalmaskdesignand

processing

34

VLSIDesignStyles- FPGA

FPGA– FieldProgrammableGateArray

arrayofconfigurablelogicblocks,

andprogrammableinterconnectstructures

Fastprototyping,costeffectiveforlowvolumeproduction

HDL(hardwaredescriptionlanguage)– isused

35http://lsiwww.epfl.ch/LSI2001/teaching/webcourse

DesignStyles– ProsandCons

36

FullCustomDesign:

Customizationforoptimizedpower,performance,area.

Highcomplexity=cost,time-to-market,highrisk.

StandardCell:

Simple,fast,reliable.

OnlyDigitaldesigns.Excesspower,wirelength,etc.

GateArray:

Reducednumberofmasksà Inexpensive.

Highpercentageofoverhead,limitedspeed.

FPGA:

Postsiliconconfigurability,veryinexpensive.

Highpercentageofoverhead.Highcostperchip.

32 41

Whatwillwelearntoday?

37

Howachipis

bornCourse

Logistics

Design

Abstraction

andStyles

Costofan

Integrated

Circuit

Howachipisborn…

38

A&Aand Specification

LogicDesign&

IPIntegration

LogicVerification

Physical Design

Sign-off&

TapeOut

PhysicalDesignFlow

39

StandardCells

HardIPs

HDLCodeSynthesizer

PlaceandRoute

StaticTiming

Analysis

Floorplan

Tapeout

DRC,LVS,LEC,

Gatelevel sim

Circuit(Custom)DesignFlow

40

Schematic

Simulation

Layout

PostLayout

Simulation

DRC/LVS/RCX

ALittleBitAboutCAD

41

Process DesignKit(PDK)

Device Library

TechFile

Schematic

Composer

AnalogDesign

Environment

LayoutDesigner

SPICESimulator

FastSPICE Simulator

AMSSimulator

ModelFile

StatisticalDistribution

AnalogLib

DesignRules

Parasitics

Waveform

Hierarchy Editor

DRC

LVS

RCX

SchematicComposer

42

Graphicaltoolfordrawingelectrical

circuits.

Usesanabstractrepresentationfor:

Devices

Sources

Wires

Allwiresareidealà R=C=0

Directlytranslatesintoanetlist:

SPICEnetlist

Spectrenetlist

V1 1 0 dc 24V2 3 0 dc 15R1 1 2 10kR2 2 3 8.1kR3 2 0 4.7k.end

AnalogDesignEnvironment

43

Graphicaltoolforcreatingtestbenches (ADE,ADE-XL).

Create“tests”thatrunsimulationsona“top-level”netlist.

Maintypesoftests:

DCOperatingPoint

DCSweep

TransientAnalysis

ACAnalysis

Define“outputs”tobeprintedorplotted.

Define“variables”toenableparametricsweeps.

Directlytranslatesintoaspicenetlist orscript(“Oceanscript”)

thatrunsthesimulationsanddisplaystheoutputs.

.dc V1 0 24 24

.print dc v(1) v(2,3)

.tran .05 1

.print tran v(1,2)

AnalogDesignEnvironment

44

Severalsimulatorscanbeusedinyoursimulation:

SPICE(Spectre)

FastSpice (UltraSim)

APS

AMS

Variousmodelscanbeusedtodescribedevices.

Cornersimulationchangesmodelstosimulateglobalprocess

variations.

MonteCarlosimulationsusestatisticaldistributionstosimulation

localprocessvariations.

Layout– ConnectivitytoSchematics

45

Afterreachingoptimalcircuittopology,thelayouteditoris

enactedtoproduceaphysicalrepresentationofthecircuit.

Theprocess“techfile”describesthevariousdesignlayersand

designrules.

Inordertoassistthelayoutdesignerincircuitcompilation,Layout-

XLusesconnectivitybetweenthelayoutandschematic:

GenerateFromSourcecreates“p-cells”oftheschematicdevices.

Netnamesconnectbetweentheschematicandlayout.

Fly-linesandWiresautomaticallyconnectnodesonthesamenet.

Pinlayersareusedtodescribeschematicports/pins.

LayoutVerification– DRC/LVS/RCX

46

DesignRuleCheck(DRC)ensuresthatthelayoutmeets

thedesignrulerequirements.

LayoutVsSchematics(LVS)ensuresthatthelayout

trulyrepresentsthecircuit.

ParasiticExtraction(RCXorPEX)extractstheparasitic

resistance,capacitanceandinductanceofthelayout.

Themostcommontoolsforperforminglayout

verificationare:

CadenceAssura/PVS

MentorGraphicsCalibre

DRC

47

DRCcanbeappliedinteractivelyin

Layout-XLbyturningon“DRD”

TheDRCcheckertestscomplex

geometricpatternsforeachlayeras

describedinthePDK’srulefile.

DRCwarningsinclude:

Circuitlevelrules

Chiplevelrules

RecommendedRules(ForDFM)

LVS

48

LVSusesagreedyalgorithmtocompare

netlists.

The“Source”netlist istheschematic

(alreadyinnetlist format).

The“Target”netlist isthelayoutas

compiledbyanextractorthatfindsdevices

andconnectsthem.

ThestartingpointfortheLVScheckeristhe

interface(pins/ports).Iftheseare

incorrect,youwillget“strange”errors.

LVSalsochecksvariousdesign

requirementssuchasbulkconnections.

RCX

49

RCXisaparasiticextractorthatcreatesanetlist that

includesthenon-idealitiesofthelayout.

Actualdevicesizes,suchasLdiff.

ResistanceandCapacitanceofwires.

CouplingCapacitance

InordertorunRCX,youmustFIRSTrunLVS.

TheoutputofRCXisalistofnetparasitics anda

netlist thatcanbepluggedbackintothecircuit

simulatorforcomparisontoprelayoutresults.

The“new”CadenceextractoriscalledQRC.

PostLayoutSimulation

50

Pre-layoutsimulationisdoneaccordingtogeneric

modelswithaveragedeviceparametersandidealwires.

Aftercreatingalayoutofyourdesign,itisessentialto

re-simulateyourdesignwiththeactualparasitics – for

betterorforworse.

Yourcircuitwillnowhaveanew“view”inadditiontoits

“schematic”view.Thisviewiscalled“extraction”or

“calibre”orsomethingsimilar.

Thecommonwaytotellthesimulatortousethisviewis

byinvokingtheHierarchyEditor.

CADToolsUsedinthisClass

51

42 31

Whatwillwelearntoday?

52

Costofan

Integrated

Circuit

Course

Logistics

Design

Abstraction

andStyles

Howachipis

born

NoFreeLunch

53

InVLSIDesign,wealwayshaveatrade-offbetween:

Foreverycircuit/system,wewillhavetoevaluatethe

specandchoosethemostbeneficialtrade-off.

InDigitalElectronicCircuits,wediscussedthebasic

metricsformeasuringSpeed,Power,andReliability.

Now,wewilldiscussCost.

Speed CostReliabilityPower

CostofIntegratedCircuits

54

NRE(non-recurrent

engineering)costs

designtimeandeffort,

maskgeneration

one-timecostfactor

Recurrentcosts

siliconprocessing,packaging,test

proportionaltovolume

proportionaltochiparea

MaskCosts

TotalCost

55

qCostperIC

qVariablecost

fixed costcost per IC = variable cost per IC +

volume⎛ ⎞⎜ ⎟⎝ ⎠

die cost + package cost+ test costvariable cost =

final test yield

No. of good chips100%

Total number of chipsYield = ×

DieCost

56

Singledie

Wafer

From http://www.amd.com

cost of wafercost of die =

dies per wafer die yield×

fixed costcost per IC = variable cost per IC +

volume⎛ ⎞⎜ ⎟⎝ ⎠

die cost + package cost+ test costvariable cost =

final test yield

EdgeLosses

57

( )2wafer diameter/2 wafer diameterDies per waferdie area 2 die area

π π× ×= −

×

fixed costcost per IC = variable cost per IC +

volume⎛ ⎞⎜ ⎟⎝ ⎠

die cost + package cost+ test costvariable cost =

final test yieldcost of wafer

cost of die = dies per wafer die yield×

WaferSize

58

Moore’sLawofWafers?

59

Defects

60

4die cost (die area) die areaf= ∝

Yield=¼=0.25 Yield=19/24=0.79

fixed costcost per IC = variable cost per IC +

volume⎛ ⎞⎜ ⎟⎝ ⎠

die cost + package cost+ test costvariable cost =

final test yieldcost of wafer

cost of die = dies per wafer die yield×

TotalCost- summary

61

fixed costcost per IC = variable cost per IC +

volume⎛ ⎞⎜ ⎟⎝ ⎠

die cost + test cost + package costvariable cost =

final test yield

cost of waferdie cost =

dies per wafer die yield×

%Yield good chips=

Beforepackaging

Afterpackaging

( )2wafer diameter/2 wafer diameterDies per waferdie area 2 die area

π π× ×= −

×

4die cost die area∝

SomeExamples(1994)

62

Chip Metal layers

Line width

Wafer cost

Def./ cm2

Area mm2

Dies/wafer

Yield Die cost

386DX 2 0.90 $900 1.0 43 360 71% $4

486 DX2 3 0.80 $1200 1.0 81 181 54% $12

Power PC 601

4 0.80 $1700 1.3 121 115 28% $53

HP PA 7100 3 0.80 $1300 1.0 196 66 27% $73

DEC Alpha 3 0.70 $1500 1.2 234 53 19% $149

Super Sparc 3 0.70 $1700 1.6 256 48 13% $272

Pentium 3 0.80 $1500 1.5 296 40 9% $417

ImportantConceptsFromThisLecture

63

q Abstraction

q Scaling

q Flavors

q Foundry

q Interconnect

q Schematics

q Simulator

q Layout

q Parasitics

q Extraction

q Interface

q Instantiate

q Hierarchy

q Verification

q Standards&Protocols

q DesignStyles

q Trade-offs

q FullCustomDesign

q StandardCellDesign

q Libraries

ImportantConceptsFromThisLecture

64

q GateArray

q SignOff

q Tapeout

q Synthesis

q Floorplan

q PlaceandRoute

q StaticTiming

q PostLayoutSimulation

q Corners

q MonteCarlo

q OceanScript

q Virtuoso

q Calibre

q Assura

q SPICE

q Netlist

q Testbench

q DCOperatingPoint

q TransientAnalysis

q DCSweep

q ACSweep

q ProcessVariations

ThreeLetterWords

65

q PDK– ProcessDesignKit

q HDL– HardwareDescriptionLanguage

q EDA– ElectronicDesignAutomation

q ASIC– ApplicationSpecificIntegratedCircuit

q FPGA– FieldProgrammableGateArray

q IP– IntellectualProperty

q DRC– DesignRuleCheck

q LVS– LayoutVs.Schematics

q RCX– Resistance/Capacitance

Extraction

q ADE– AnalogDesign

Environment

FurtherReading

66

J.Rabaey,“DigitalIntegratedCircuits”2003,Chapter1.3

E.Alon,BerkeleyEE-141,Lecture2(Fall2009)http://bwrc.eecs.berkeley.edu/classes/icdesign/ee141_f09/

…anumberofyearsofexperience!