CMOS工艺

L01–VLSIOverview16.371–Fall200209/04/026.371IntrotoVLSISystemsFall2002Lecturers:KrsteAsanovic,ChrisTermanWebsite:–VLSIOverview26.371–Fall200209/04/02ModernsystemsengineeringPersonalComputer:Hardware&SoftwareCircuitBoard:≈8/system1-2GdevicesIntegratedCircuit:≈8-16/PCB.25M-16MdevicesModule:≈8-16/IC100KdevicesCell:≈1K-10K/Module16-64devicesGate:≈2-16/Cell8devicesSchemeforrepresentinginformationMOSFETL01–VLSIOverview36.371–Fall200209/04/02So,what’s6.371allabout?You’llgetatop-downtourofhowintegratedcircuitsareengineered.We’lltalkabout♦howyoutackletheproblemofdesigningcircuitswithmillionsofgates–andhaveeverythingworkthefirsttime!♦howarchitecturalandimplementationchoicesareaffectedbythetargettechnology(inourcase,CMOS)♦variousdesignandlayouttechniquesforcreatingcombinationalandsequentialcircuits,datapaths,memories,buffers,regularlogicstructures,…♦computer-aideddesign(CAD)tools–lettingprogramsdotheheavylifting.Thefunpart:you’llgettotryityourselfinthelabs!L01–VLSIOverview46.371–Fall200209/04/02What’sexpectedofyouDesignexercisestobedoneinthe“lab.”ReadingsfromWeste&Eshraghian(seecoursewebsiteforhowtoorderthebook).Specify,architect,design,layoutandverifyamodest-sizedCMOScircuit.PrepareaWeb-pagedescriptionandgiveabriefpresentationthelastweekofclass.Workaspartofa2-or3-personteam.Two80-minutein-class,closed-bookquizzes(10/11,11/15).Meanttobeducksoupifyou’vebeencomingtolecturesanddoingthehomework.Homework20%offinalgradeProject40%offinalgradeQuizzes40%offinalgradeL01–VLSIOverview56.371–Fall200209/04/02WhatisaVLSIcircuit?VERYLARGESCALEINTEGRATEDCIRCUITTechniquewheremanycircuitcomponentsandthewiringthatconnectsthemaremanufacturedsimultaneouslyintoacompact,reliableandinexpensivechip.Early(circa1977)characterizationofcircuit“size”beforepeoplerealizedthatthenumberofcomponentsperchipwasquadruplingevery24months(akaMoore’sLaw)!L01–VLSIOverview66.371–Fall200209/04/02DawnofthetransistorBellLabslaysthegroundwork:1940:RusselOhldevelopsPNjunctionwhichproduces0.5Vwhenexposedtolight.1945:Bellsetsuplabinthehopesofdeveloping“solidstate”componentstoreplaceexistingelectromechanicalsystems.WilliamSchockley,JohnBardeen,WalterBrattain:allsolid-statephysicists.FocusonSiandGe.1947:BardeenandBrattaincreatepoint-contacttransistorw/twoPNjunctions.Gain=18.AnnouncedinJuly1948.Buttreatedasanoveltyuntil1951inventionofjunctiontransistor.BellLabswillingtolicensetherightstothetransistortoanycompanyforaroyalty(whichwaswaivedforhearingaidcompaniesasagesturetoAlex.G.Bell).Transistorwasgood:smaller,faster,morereliableandeconomicalbutthisisonlyhalfthestorysincethecircuits,albeitsmaller,werestillconstructedinmuchthesameway.L01–VLSIOverview76.371–Fall200209/04/02Dawnofthetransistor(II)1951:Shockleydevelopsjunctiontransistorwhichcanbemanufacturedinquantity.1952:GWADummerforecasts“solidblock[with]layersofinsulating,conductingandamplifyingmaterials”1954:Thefirsttransistorradio!Also,TImakesfirstsilicontransistor(price$2.50)1956:Bardeen,Shockley,BrattainreceiveNobelPrize.(U.S.Patents#2,502,488,#2,524,035)L01–VLSIOverview86.371–Fall200209/04/02EarlyIntegrationJackKilbywasdeniedentrytoMITbecauseofpoorhighschoolgrades(wenttoUofI).Kilbyworkedonminiaturizedcomponentsduringthewarandexperimentedwithphotolithography.Wentto1952BellLabstransistorcourse.HighlaborcostsatTIgotKilbythinkingabout“solidcircuits”overtheJuly1959plantclosing.Builtphase-shiftoscillatoranditworkedon9/12/59.Bytheendoftheyear,hehadconstructedseveralexamples,includingtheflip-flopshowninthepatentdrawingabove.Componentsareconnectedbyhand-solderedwiresandisolatedby“shaping”andPNdiodesusedasresistors.InDecember2000,KilbywasawardedtheNobelPrizeinphysicsforthiswork.(U.S.Patent#3,138,743)L01–VLSIOverview96.371–Fall200209/04/02Makingitreal…RobertNoyceexperimentedinthelate40’swithtransistorswhileaphysicsmajoratcollege(hisprofwasfriendswithBardeenatBellandsohadearlyaccesstotransistors).HecametoMITwhere“muchtohissurprise,fewpeoplehadevenheardaboutthetransistor.”AftergettinghisPhDin1953,heworkedinindustry,finallyarrivingatMountainView,CAandShockleySemiconductorLabsin1955.In1957,NoyceleftShockley’slab(Schockleywasn’tthebestofmanagers)toformFairchildSemiconductorwithJeanHoerni.GordonMooreisanotherfounder.Inearly1958,HoerniinventstechniquefordiffusingimpuritiesintothesilicontobuildplanartransistorsandthenusingaSiO2insulator.Inspringof1959,KurtLehovecatSpragueElec.Co.hereinNorthAdams,MAinventsisolationtechniqueusingback-to-backpnjunctions.Inmid1959,NoycedevelopsfirsttrueICusingplanartransistors,back-to-backpnjunctionsforisolation,diode-isolatedsiliconresistorsandSiO2insulationwiredusinghisinnovation:usingmetaldepositedbyevaporationthroughamasktoformtheinterconnect--keepingtheICflatandeasytobuild.(U.S.Patent#2,981,877)L01–VLSIOverview106.371–Fall200209/04/021960’s:eraofintegration(socialandelectrical!)1963:Densitiesandyieldsareimproving.Thiscircuithasfourflipflops.0.06”0.038”1966:RobertDennardinvents1-TDRAMatIBMTJWatsonResearchCenter.1967:Fairchildmarketsthissemi-customchip.Transistors(organizedincolu