Very Large Scale Integrated Circuit

Developmenthistory

Inthe1920s,someinventorstriedtomasterthemethodofcontrollingthecurrentinsolid-statediodes,andtheirideaswererealizedinbipolartransistorslater.However,theirvisionwasnotrealizeduntiltheendoftheSecondWorldWar.Duringthewar,peoplefocusedtheirenergyonmanufacturingmilitaryproductssuchasradar.Therefore,thedevelopmentoftheelectronicsindustrywasnotasrapidasafterwards,butpeople’sunderstandingofsemiconductorphysicshasgraduallyincreasedandthelevelofmanufacturingtechnologyhasgraduallyimproved.Afterthewar,manyscientistsresumedresearchonsolid-stateelectronicdevices.In1947,thefamousBellLabssuccessfullydevelopedatransistor.Sincethen,theresearchdirectionofelectronicshasshiftedfromvacuumtubestosolid-stateelectronicdevices.

Atthetime,thetransistorseemedtohavethecharacteristicsofsmallsizeandhighefficiency.Inthe1950s,someelectronicengineershopedtodevelopmoreadvancedandcomplexcircuitsbasedontransistors.However,withtheincreaseincircuitcomplexity,theimpactoftechnicalissuesondeviceperformancehasgraduallyattractedpeople'sattention.

Complexcircuitslikecomputermotherboardsoftenhavehigherrequirementsforresponsespeed.Ifthecomponentsofthecomputeraretoolarge,orthewiresbetweendifferentcomponentsaretoolong,electricalsignalscannotpropagatefastenoughinthecircuit,whichwillcausethecomputertoworkslowly,lowefficiency,andevencauselogicerrors.

In1958,JackKilbyofTexasInstrumentsfoundasolutiontotheaboveproblems.Heproposedthatallcomponentsandchipsinthecircuitcanbemadeofthesameblockofsemiconductormaterial.Hiscolleagueswereonvacationatthetime.Aftertheyfinishedtheirvacation,Kilbyimmediatelyshowedhisnewdesign.Subsequently,hedevelopedatestversionofthisnewcircuit.InSeptember1958,thefirstintegratedcircuitwassuccessfullydeveloped.Althoughthisintegratedcircuitlooksveryroughandhassomeproblems,theintegratedcircuitisindeedaninnovativeconceptinthehistoryofelectronics.Byintegratingallthecomponentsonthesamematerialblockandconnectingthevariouspartsthroughtheuppermetallizationlayer,separateindependentcomponentsarenolongerneeded,thusavoidingthestepsofmanuallyassemblingcomponentsandwires.Inaddition,thefeaturesizeofthecircuitisgreatlyreduced.Withthegradualdevelopmentofelectronicdesignautomation,manyprocessesinthemanufacturingprocesscanbeautomatedandcontrolled.Sincethen,theideaof​​integratingallcomponentsonasinglesiliconchiphasbeenrealized.TheeraofSmallScaleIntegration(SSI)beganintheearly1960sandthenwentthroughMediumScaleIntegration(MSI,1960).Late),large-scaleintegratedcircuitsandverylarge-scaleintegratedcircuits(early1980).ThenumberofVLSItransistorscanreach10,000.

Classification

Integratedcircuitscanbedividedintosmall-scaleintegratedcircuits,medium-scaleintegratedcircuits,large-scaleintegratedcircuits,verylarge-scaleintegratedcircuits,andverylarge-scaleintegratedcircuitsaccordingtothelevelofintegration.Andhuge-scaleintegratedcircuits.

Small-scaleintegratedcircuitsappearedin1960,containing10-100elementsor1-10logicgatesonasiliconchip.Suchaslogicgatesandflip-flops.Ifasmall-scaledigitalintegratedcircuit(SSI)isusedtodesignacombinationallogiccircuit,thegatecircuitisusedasthebasicunitofthecircuit,sothesimplificationofthelogicfunctionshouldminimizethenumberofgatecircuitsused,andthenumberofgateinputsisalsoleast.

MediumScaleIntegration(MSI)

Appearedin1966,itcontains100-1000componentsor10-100logicgatesonasiliconchip.Suchas:integratedtimers,registers,decoders,etc.

Ifyouchooseamedium-scaleintegratedcircuit(MSI)todesignacombinationallogiccircuit,thenumberofintegratedcircuitsusedistheleast,thevarietyistheleast,andtheconnectionsbetweentheintegratedcircuitsarealsotheleast.Thisoftenneedstotransformthelogicalfunctionexpressionintotheexpressionformrequiredbytheselectioncircuit,andsometimesthestandardparadigmcanbeuseddirectly.

AlthoughMSImedium-scalecombinationallogicdeviceshavestrongerfunctionsthansmall-scaleintegratedcircuitsSSI,theyarenotasspecializedaslarge-scaleintegratedcircuitsLSI.Althoughtherearemanytypesofthesedeviceproducts,theyarenotItmayfullymeettheuser'srequirements,whichrequiresmultiplechipstobecascadedtoexpanditsfunctions,andsomestandardmedium-scaleinheritedcomponentscanbeusedtoimplementothercombinatoriallogiccircuitdesigns.Whenusingmedium-scaleintegratedcomponentsforcombinatoriallogiccircuitdesign,themethodistoselectasuitableMSI,andthentransformthelogicalexpressionaftertheactualproblemistransformedintotheexpressionformoftheresponseMSI.Comparedwiththecombinationallogiccircuitdesignedwithgatecircuit,thecombinationallogiccircuitdesignedwithMSIisnotonlysmallinsizeandlighterinweight,butalsoimprovesthereliabilityofwork.

Thecascadefromtheselectionofmedium-scaledatacanexpandthenumberofwaysofselectingdata,anditsfunctionexpansioncanbeusednotonlyforcombinationallogiccircuits,butalsoforsequentiallogiccircuits.Incombinationallogiccircuits,therearemainlythefollowingapplications:

(1)Cascadeexpansiontoincreasethenumberofselectedchannelsandbits,whichcanrealizedatatransmissionfrommultiplebitstomultiplebits;

(2)Asalogicfunctiongeneratortorealizethedesignofanycombinationallogiccircuit.

LargeScaleIntegratedCircuits(LSI)

Appearedin1970,containing103-105componentsor100-10,000logicgatesonasiliconchip.Suchas:semiconductormemory,somecomputerperipherals.628512,628128(128K)Themaximumcapacityis1G.

VeryLargeScaleIntegratedCircuits(VLSI)

Integratedcircuitswithmorethan100,000componentsormorethan10,000gatecircuitsonachip,CalledVLSI.Verylargescaleintegratedcircuitsweresuccessfullydevelopedinthelate1970sandaremainlyusedtomanufacturememoriesandmicroprocessors.The64k-bitrandomaccessmemoryisthefirstgenerationofverylarge-scaleintegratedcircuits,whichcontainsapproximately150,000componentsandhasalinewidthof3microns.

TheintegrationlevelofVLSIhasreached6milliontransistors,andthelinewidthhasreached0.3microns.Electronicequipmentmanufacturedwithverylargescaleintegratedcircuitshassmallsize,lightweight,lowpowerconsumptionandhighreliability.UsingVLSItechnology,anelectronicsub-systemandeventheentireelectronicsystemcanbe"integrated"onachiptocompletevariousfunctionssuchasinformationcollection,processing,andstorage.Forexample,theentire386microprocessorcircuitcanbeintegratedonachipwithanintegrationlevelof2.5milliontransistors.Thesuccessfuldevelopmentofverylarge-scaleintegratedcircuitsisaleapinmicroelectronicstechnology,whichhasgreatlypromotedtheprogressofelectronictechnology,therebydrivingthedevelopmentofmilitarytechnologyandciviliantechnology.Verylargescaleintegratedcircuitshavebecomeanimportantindicatortomeasurethelevelofacountry'sscientific,technologicalandindustrialdevelopment,anditisalsoanareawherethecompetitionismostintenseintheworld'smajorindustrialcountries,especiallytheUnitedStatesandJapan.

UltraLarge-ScaleIntegration(ULSI)

In1993,withthesuccessfuldevelopmentof16MFLASHand256MDRAMintegratedwith10milliontransistors,itenteredtheultra-largescaleintegratedcircuit.ULSI(UltraLarge-ScaleIntegration)era.Thenumberofintegratedcomponentsofverylargescaleintegratedcircuitsisbetween107and109.

TherapidgrowthofULSIcircuitintegrationmainlydependsonthefollowingtwofactors:oneisthatthecrystalgrowthtechnologyhasreachedaveryhighlevel;theotheristhecontinuousimprovementofmanufacturingequipment,theprocessingaccuracy,automationandreliabilityTheimprovementhasbroughtthedevicesizeintothedeepsub-micronrange.Thesiliconsinglecrystalpreparationtechnologycanmaketheradialparametersofthecrystaluniform,reducethemicro-defectsinthebody,andtheaveragedefectsizeof0.1~0.3umcanbelessthan0.05/cm2.Acompleteunderstandingofthetheoreticalmodelofdefectsinducedduringcircuitprocessinghasalsobeendeveloped,andacompletesetofcrystalprocessingtechnologyhasbeendeveloped.Thecontinuousincreaseinthediameterofsiliconwafersusedintheproductionofcircuitshasledtoasubstantialincreaseinproductionefficiency,andthediameterofsiliconwafershasreached12inches.Thereductionofmicro-defectsincreasesthechipyield.Asiliconchipwith0.02defectspersquarecentimetercanmaketheyieldof256MBDRAMreach80~90%.

GigaScaleIntegration(GSI)

In1994,duetothesuccessfuldevelopmentof1GDRAMintegrating100millioncomponents,itenteredthegiganticscaleintegratedcircuitGSI(GigaScaleIntegration).)era.Thenumberofintegratedcomponentsofahuge-scaleintegratedcircuitismorethan109.

Developmentstatus

Asoflate2012,billionsoftransistorprocessorshavebeencommerciallyavailable.Asthesemiconductormanufacturingprocessjumpsfromthe32-nanometerleveltothenext22-nanometerlevel,thistypeofintegratedcircuitwillbecomemorecommon,althoughitwillencounterchallengessuchasprocessangledeviations.Anotableexampleisthegraphicsprocessorcode-named‘GK110’,thefirstdisplaycoreofNvidia’sGeForce700series,whichusesall7.1billiontransistorstoprocessdigitallogic.AndmostofItanium'stransistorsareusedtoformits32-megabytethree-levelcache.ThechipintegrationleveloftheIntelCorei7processorhasreached1.4billiontransistors.Thedifferencebetweentheadopteddesignandtheearlydaysisthatitwidelyuseselectronicdesignautomationtools.Designerscanfocusmostoftheirenergyonthehardwaredescriptionlanguageexpressionofcircuitlogicfunctions,whilefunctionalverification,logicsimulation,logicsynthesis,layout,routing,Thelayout,etc.canbecompletedwithcomputerassistance.

Insufficient

Duetothecontinuousexpansionoftechnologyandtheincreasingcomplexityofmicroprocessors,microprocessordesignershaveencounteredseveralchallenges.

1Powerconsumptionandheatdissipation:Asthescaleofcomponentintegrationincreases,theheatpowerperunitvolumeisgraduallyincreasing,buttheheatdissipationareaof​​thedeviceremainsunchanged,causingtheheatdissipationperunitareatofailtomeettherequirements.Atthesametime,thestaticpowerconsumptioncausedbytheweaksub-thresholdcurrentofasingletransistorhasbecomeincreasinglysignificantduetothesubstantialincreaseinthenumberoftransistors.Somelow-powerdesigntechniqueshavebeenproposed,suchasdynamicvoltageandfrequencyscaling(DVFS),toreducethetotalpowerdissipation.

2Processdeviation:Asphotolithographytechnologyislimitedbyopticallaws,higherprecisiondopingandetchingwillbecomemoredifficult,andthepossibilityoferrorwillincrease.Thedesignermustcarryouttechnicalsimulationbeforechipmanufacturing.

3Morestringentdesignrules:Duetotheproblemsofphotolithographyandetchingprocesses,thedesignrulesforintegratedcircuitlayoutmustbestricter.Whendesigningthelayout,thedesignermustalwaysconsidertheserules.Thetotalcostofcustomdesignhasreachedacriticalpoint,andmanydesignagenciestendtostartwithelectronicdesignautomationtoachieveautomaticdesign.

4Designclosure:Astheclockfrequencyofdigitalelectronicapplicationstendstorise,designersfinditmoredifficulttomaintainlowclockskewontheentirechip.Thissparkedinterestinmulti-core,multi-processorarchitectures(seeAmdahl'sLaw).

5Cost:Asthesizeofthecrystalgrainshrinks,thesizeofthewaferbecomeslarger,andthenumberofcrystalgrainsperwaferareaincreases,sothecomplexityofthephotomaskusedinthemanufacturingprocessincreasessharply.Modernhigh-precisionphotomasktechnologyisveryexpensive.

Manufacturer

"Ultra-largescale"hasbeensaidmanyyearsago.Themostadvancedmanufacturingprocesshasreachedtheorderof7nanometers,andtheactualmassproductionprocessesaremostlyat14and22nanometers.Sortedbysales,thetopthreecompaniesare:Intel(U.S.),Samsung(SouthKorea),andTSMC(Taiwan).MostothercompaniesareEuropean,American,JapaneseandTaiwanesecompanies.OnlySMICinmainlandChinacankeepupwiththetrendoftechnologicaldevelopment.