25_Integrated Circuits(集成电路)

©2000byCRCPressLLC25IntegratedCircuits25.1IntegratedCircuitTechnologyTechnologyPerspectives•TechnologyGenerations•NationalTechnologyRoadmapforSemiconductors25.2Layout,Placement,andRoutingWhatIsLayout?•FloorplanningTechniques•PlacementTechniques•RoutingTechniques25.3Application-SpecificIntegratedCircuitsIntroduction•PrimaryStepsofVLSIASICDesign•IncreasingImpactofInterconnectionDelaysonDesign•GeneralTransistor-LevelDesignofCMOSCircuits•ASICTechnologies•InterconnectionPerformanceModeling•ClockDistribution•PowerDistribution•AnalogandMixed-SignalASICs25.1IntegratedCircuitTechnologyJoeE.BrewerIntegratedcircuit(IC)technology,thecornerstoneofthemodernelectronicsindustry,issubjecttorapidchange.Electronicengineers,especiallythoseengagedinresearchanddevelopment,canbenefitfromanunderstandingofthestructureandpatternofgrowthofthetechnology.TechnologyPerspectiveAsolidstateICisagroupofinterconnectedcircuitelementsformedonorwithinacontinuoussubstrate.Whileanintegratedcircuitmaybebasedonmanydifferentmaterialsystems,siliconisbyfarthedominantmaterial.Morethan98%ofcontemporaryelectronicdevicesarebasedonsilicontechnology.Ontheorderof85%ofsiliconICsarecomplementarymetaloxidesemiconductor(CMOS)devices.FromaneconomicstandpointthemostimportantmetricforanICisthe“leveloffunctionalintegration.”SincetheinventionoftheICbyJackKilbyin1958,thelevelofintegrationhassteadilyincreased.Thepleasantresultisthatcostandphysicalsizeperfunctionreducecontinuously,andweenjoyaflowofnew,affordableinformationprocessingproductsthatpervadeallaspectsofourday-to-daylives.Thehistoricalrateofincreaseisadoublingoffunctionalcontentperchipevery18months.Forengineerswhoworkwithproductsthatusesemiconductordevices,thechallengeistoanticipateandmakeuseoftheseenhancedcapabilitiesinatimelymanner.Itisnotanoverstatementtosaythatsurvivalinthemarketplacedependsonrapid“design-in”anddeployment.Forengineerswhoworkinthesemiconductorindustry,orinitsmyriadofsupportingindustries,thechallengeistomaintainthisrelentlessgrowth.Theentireindustryismarchingtoadrumbeat.Thecostoftechnologydevelopmentandtheinvestmentinplantandequipmenthaverisentobillionsofdollars.Companiesthatlagbehindfaceaseriouslossofmarketshareand,possibly,direeconomicconsequences.JoeE.BrewerNorthropGrummanCorporationMedhiR.ZarghamandSpyrosTragoudasSouthernIllinoisUniversityStuartTewksburyWestVirginiaUniversity©2000byCRCPressLLCTechnologyGenerationsTheconceptofatechnologygenerationemergedfromanalysisofhistoricalrecords,wasclearlydefinedbyGordonMooreinthe1960s,andcodifiedasMoore’slaw.Thecurrentversionofthelawisthatsucceedinggenerationswillsupportafourtimesincreaseincircuitcomplexity,andthatnewgenerationsemergeatapproximately3-yearintervals.Theassociatedobservationsarethatlineardimensionsofdevicefeatureschangebyafactorof0.7,andtheeconomicallyviablediesizegrowsbyafactorof1.6.Minimumfeaturesizestatedinmicrons(micrometers)isthetermusedmostfrequentlytolabelatechnologygeneration.“Feature”referstoageometricobjectinthemasksetsuchasalinewidthoragatelength.The“minimumfeature”isthesmallestdimensionthatcanbereliablyusedtoformtheentity.Figure25.1displaysthetechnologyevolutionsequence.Inthediagramsucceedinggenerationsarenumberedusingthecurrentgenerationasthe“0”reference.Becausethismaterialwaswrittenin1996,the“0”generationisthe0.35mmminimumfeaturesizetechnologythatbeganvolumeproductionin1995.Anindividualdevicegenerationhasbeenobservedtohaveareasonablywell-definedlifecyclewhichcoversabout17years.Thefirstyearofvolumemanufactureisthereferencepointforageneration,butitslifetimeactuallyextendsfurtherinbothdirections.AsshowninFig.25.2,onecanthinkofthestagesofmaturityasrangingoveralinearscalewhichmeasuresyearstoproductioninboththeplusandminusdirections.The17-yearlifecycleofasinglegeneration,withnewgenerationsbeingintroducedat3-yearintervals,meansthatatanygiventimeuptosixgenerationsarebeingworkedon.Thistendstoblurthesignificanceofresearchnewsandcompanyannouncementsunlessthereaderissensitivetothetechnologyoverlapintime.Tovisualizethissituation,considerFig.25.3.Thetoprowlistscalendaryears.Thesecondrowshowshowthelifecycleofthe0.35mmgenerationrelatestothecalendar.Thethirdrowshowsthelifecycleofthe0.25mmgenerationvs.thecalendar.Lookingdownanycolumncorrespondingtoaspecificcalendaryear,onecanseewhichgenerationsareactiveandidentifytheirrespectivelifecycleyear.FIGURE25.1Semiconductortechnologygenerationtimesequence.FIGURE25.2Lifecycleofasemiconductortechnologygeneration.FIGURE25.3Timeoverlapofsemiconductortechnologygenerations.©2000byCRCPressLLCOneshouldnotinterpretthe17-yearlifecycleasmeaningthatnoworkisbeingperformedthatisrelevanttoagenerationbeforethe17-yearperiodbegins.Forexample,manyorganizationsareconductingexperimentsdirectedattransistorswithgatelengthssmallerthan0.1mm.Thisauthor’sinterpretationisthatwhenbasicresearcheffortshaveexploredtechnologyboundaryconditions,theconditionsareripeforaspecificgenerationtobegintocoalesceasauniqueentity.Whenabodyofresearchbeginstoseekcompatiblematerialsandprocessestoenabledesignandproductionatthetargetfeaturesize,thegeneration