機(jī)械畢業(yè)設(shè)計英文外文翻譯465水射流與激光結(jié)合加工在半導(dǎo)體中的應(yīng)用

附錄1英文翻譯水射流與激光結(jié)合加工在半導(dǎo)體中的應(yīng)用P.Ogawa,D.Perrottet，F(xiàn).Wagner，R.Housh，B.Richerzhagen**SA，ChSynova.delaDentd'Oche，CH-1024Ecublens，瑞士電子郵件：richerzhagen@synova.ch摘要最近幾年，半導(dǎo)體晶圓已經(jīng)占據(jù)了市場的很大一部分，它在復(fù)合材料的生產(chǎn)中超過其他硅產(chǎn)品的知名度。由于這些III/V半導(dǎo)體材料的加工工藝要求高，因此產(chǎn)生了許多與傳統(tǒng)加工不同的加工工藝和方法。不同的切割方法之間存在著顯著差異。在傳統(tǒng)切割中，由于存在嚴(yán)重的熱損失，使工件的切口處產(chǎn)生結(jié)晶體?，F(xiàn)在，有了讓人滿意的解決方法---與激光微射流（lmj）這一成果，一個革命性耦合激光和水射流的技術(shù)。這是一種比其他加工方法更快捷和清潔的加工方法，并且能產(chǎn)生很高的加工精度。此外，它可以切割任意的形狀，這在其他傳統(tǒng)加工方法中是不可能的。最后，安全問題不應(yīng)該忘記。事實(shí)上，由于融入了水射流，在加工過程的檢測中沒有發(fā)現(xiàn)產(chǎn)生有毒氣體。關(guān)鍵詞：激光切割，水射流引導(dǎo)激光，砷化鎵，化合物半導(dǎo)體。1.導(dǎo)言硅占半導(dǎo)體晶圓市場已經(jīng)超過三十年。然而，持續(xù)的要求，更高的速度和增加小型化帶動無線電和寬帶通訊行業(yè)的發(fā)展，使III/V半導(dǎo)體材料，如砷化鎵（GaAs）的和磷化銦（InP）的需求量增大。事實(shí)上，這些材料的電學(xué)性比純硅更具有優(yōu)勢，它們在高頻率的運(yùn)作，改善信號接收效果，更好的處理信號在擁擠的頻帶，和增大大的功率效率更有優(yōu)勢。根據(jù)“IC的洞察”的市場研究（公司總部設(shè)在斯科茨代爾，亞利桑那州），在2002年占市場87％的份額的化合物半導(dǎo)體集成電路仍然主要是基于砷化鎵。半導(dǎo)體市場已經(jīng)把他們生產(chǎn)的產(chǎn)品定在這個方向?！癐C的洞察”調(diào)查，在2002年到2007年化合物半導(dǎo)體每年平均的增長率為22%。相較之下，比同一時期的IC市場增長率為10％。在2000年該化合物半導(dǎo)體IC市場的高峰24.2億美元，但在2002年下跌至16.9億美元?！癐C的洞察”預(yù)測增長強(qiáng)勁，在隨后的歲月，與不斷擴(kuò)大到2007年，當(dāng)市場將會擴(kuò)大一倍以上，達(dá)46.5億美元。今天，砷化鎵市場已不再被認(rèn)為是為特定盈利市場。最重要的應(yīng)用不光是無線通信業(yè)，砷化鎵是揭示了它的潛力在光電電子應(yīng)用在軍事，醫(yī)療，特別是LED照明領(lǐng)域。標(biāo)準(zhǔn)的生產(chǎn)技術(shù)仍然需要變得更加適應(yīng)這一新的高增長的市場。減少芯片尺寸低于500um的規(guī)定，使用更薄的晶圓比lOOum的，縮小晶圓厚度也有其優(yōu)點(diǎn)，可以降低其溫度梯度。由于砷化鎵是非常脆弱，改善方法是用樹脂葉片。這需要提高切削速度和質(zhì)量。此外，考慮制造晶圓的切割過程是精密的，這需要使用新的切割方法，達(dá)到高生產(chǎn)率。此外，砷化鎵的價格昂貴也是需要考慮的。另一個不如忽視的重要方面是：制造和加工的化合物半導(dǎo)體，尤其是砷化鎵，對安全有嚴(yán)重的威脅。砷化鎵氣體有毒，是引起人類致癌物質(zhì)。這些事實(shí)提出了很多的關(guān)注，從環(huán)境，健康和安全的立場。2.比較不同的切割方法目前有三種加工方法，用來加工砷化鎵晶圓，即砂輪切斷，刨切，和激光引導(dǎo)水射流切割。由于砷化鎵的特定屬性，缺點(diǎn)不容忽視，當(dāng)切割硅晶片，因為劃片砷化鎵在加工時有很多缺點(diǎn)。傳統(tǒng)的切割方法在加工半導(dǎo)體時會遇到很多問題。激光引導(dǎo)水射流切割主要優(yōu)勢切割硅晶圓時的切縫質(zhì)量高。如果是傳統(tǒng)的切割方法的話，由于硅晶圓非常的脆，加工出高質(zhì)量的切縫是很難實(shí)現(xiàn)的。刨切寬度較大的砷化鎵時，加工面面要拓寬，從而減少芯片數(shù)量的百分之晶圓。此外，由于機(jī)械的限制，導(dǎo)致工件的邊緣往往容易破碎，從而使該件無法使用。在一般情況下，要達(dá)到一個符合條件的切割質(zhì)量,切削速度要在3到12mm/s之間,這主要取決于晶圓的厚度，從而大大減緩了整個加工效率表1顯示的是3種切割方法的比較。DicingmethodMinimalstreetwidthTimetoprocessawaferDiceshapelimitationMechanicalproblemsAbrasiveSaw80pm50minutesLinearNosizelimitChippingBrokencomersScribeandBreakbpm30minutesLinearAtleast1x1mmBrokenwafersLaserMicrojet40pm15minutesFree-shapeAtleastO.5xO.5tnmNochippingNobrokencomersTable1:ComparisonofthethreedicingmethodsforatypicalGaAswafer-400cuts,8inches,200pmthick160°C的［2160°C的［2WincfoH Liiser尉如協(xié)'Fi罠.LPrinci卩oftheLaserMierojetdicingtechnique水射流切割可以在同樣的毛配件中切削出更多的工件，既節(jié)約材料降低成本。在加工一個昂貴的復(fù)合材料，這是一個真正的優(yōu)勢。舉例來說，晶圓并不總是沿內(nèi)切線。這往往是晶圓破損的主要原因。這意味著，要清楚處理大量的廢棄晶圓時間和精力。利用激光引導(dǎo)水射流，不需要將它與一個標(biāo)準(zhǔn)的激光看待，可以增加砷化鎵晶圓的切削速度，提高切縫質(zhì)量。此外，它可以切割任意形狀，包括多項目晶圓，這在傳統(tǒng)切割中是不可能的。3.水射流引導(dǎo)激光加工激光引導(dǎo)水射流采用了薄水射流作為一個引導(dǎo)件，以指導(dǎo)工件加工（參見圖1）。除了引導(dǎo)激光，水射流冷卻作用正是它的優(yōu)勢所在，它可以降低切削時的溫度，也就消除了材料的熔融。事實(shí)上，在激光引導(dǎo)水射流是一個低溫切割Loser系統(tǒng)，在任何切削過程中檢測的工作的切削溫度不會超過FtHidinglefts這種水射流很安全，在晶圓在切割中不存在由于機(jī)械和熱而產(chǎn)生的損失（見圖2）。該水射流提供了一個不斷切縫寬度等于直徑的射流，因此，特別是對非常脆和難以加工材料如砷化鎵，即使厚度小25“m也可加工，（25至75“m的根據(jù)該噴嘴直徑）。另一個明顯的優(yōu)勢，這種水射流對于此特定的應(yīng)用是當(dāng)工件變薄時它的切削速度和質(zhì)量會增加，而在傳統(tǒng)切割中，這是剛好相反。薄砷化鎵晶圓，可實(shí)現(xiàn)非常高切割速度。傳統(tǒng)的激光切割砷化鎵時產(chǎn)生大量的碎片，很難消除，甚至可以破壞附近的活性成分。在水射流切割中，這個問題已經(jīng)克服。使用一種特殊的薄水膜，新技術(shù)的具體不斷晶圓清潔和免費(fèi)的粒子。由此產(chǎn)生的水平芯片的污染，比傳統(tǒng)的切削方法要小得多。任意形狀的切割，在薄晶圓加工中已變得日益重要，為各種應(yīng)用在微電子學(xué)和醫(yī)學(xué)，在其中的任意形狀使用。傳統(tǒng)技術(shù)不能提供所需的靈活性和兩維自由度。圖3介紹了水射流全方位的定向切割。左圖的砷化鎵晶圓厚175pm,切縫寬75pm的，所取得的速度15mm/s（點(diǎn)表面上是沒有殘留）。該切削的晶圓（右側(cè)）是250pm厚，切削速度2mm/s。Fig.3.Fig.3.Omni-directionalcutting,kefwidth75pm-Leg:GaAs(thedotsonthesurfacearcnotresiduesfiomthecutting卩roccss)-Right:InP4.安全關(guān)于安全問題，多次對水射流測試表明在切割過程中空氣里沒有發(fā)現(xiàn)存在砷化氫的氣體，切割砷化鎵晶圓[3]，一個重要的差異，以傳統(tǒng)激光切割為例（見表2）PELDetectedduringthetestRecommandationsArsinegas|ppmjTLV=0.05NotdetectedAirconcentrationofAs|pg/m}|10(OSHAcancerhazard)130(incuttingchamber4(outsidecuttingchamber)ExhaustsystemwithaparticulatefilterWaterconcentrationofAs[pg/L]<2062700Closedrecycling,ArsenicfilterArsenicinthehumanbody||igZL|BE1=3550(EPA)5.2(before)9.4(after)GlovesandaHEPAfilterWipesampleresults||ig/cm3|I30(incuttingchamber)0.062(nexttomachine)Post-cleaningTable2:ResultsfromtheGaAssafetytests這是不得不令人驚訝，因為激光引導(dǎo)水射流是水射流和再加上在一個很短激光脈沖（約450ns）相互作用的雷射光與物質(zhì)。由于有水的存在，在切割時不會產(chǎn)生有毒氣體，而是是有毒氣體溶解到水中。因為廢水中砷的濃度很高，所以廢水應(yīng)當(dāng)適當(dāng)?shù)倪^濾或循環(huán)。與傳統(tǒng)切割相比，激光引導(dǎo)水射流切割砷化鎵不需要任何額外的保安系統(tǒng)。5.結(jié)論總括而言，較傳統(tǒng)的切割方法，水射流切割展示了無可爭議的優(yōu)勢。100“m厚的晶圓可以切割在六60mm/s和卓越的品質(zhì)是達(dá)成共識。甚至，盡管傳統(tǒng)方法已有所改善所做，多年來，他們將很快取代晶圓變薄和聘用更多的成本和關(guān)鍵材料。[1]“2003年麥卡琳報告”，新聞稿，IC的洞察，2003年。[2]N.Dushkina,B.Richerzhagen:“劃片砷化鎵晶圓與思諾瓦激光微-挑戰(zhàn)，改善和安全[3]N.Dushkina“安全切割砷化鎵晶圓與雷射器”，技

術(shù)文件的工業(yè)標(biāo)準(zhǔn)結(jié)構(gòu)，第一卷。438，175-183，2003。附錄2英文原文□加y辺口ma』口口口0口moAnnnmj□兀。?？诳赺歸。-4』』10—EU^ELi^ELP.Ogawa,D.Perrottet,F.Wagner,R.Housh,B.Richerzhagen**SynovaSA,Ch.DelaDentd'Oche,CH-1024Ecublens,SwitzerlandE-mail:richerzhagen@synova.chABSTRACTForafewyearsnowthesemiconductorwafermarkethasturnedasubstantialpartofitsproductiontowardscompoundmaterials,fasterthanthewell-knownsilicon.ThemechanicalandchemicalpropertiesoftheseIII/Vsemiconductormaterials(ofwhichthemostusedbeinggalliumarsenide,GaAs)requirenewspecializedtechnologies.Inparticular,thesingulationprocessisprovedtobedelicate.Differentdicingmethodsexist,butimportantdifferencesinresultscanbeobserved.Thesawcreatesconsequentchippingaswellasbrokenedges.Conventionallasersshouldbeavoidedbecauseofimportantheatdamages.Thescribeandbreakmethodcancreatecracksthattendtobreakwafers.ThemostsatisfyingresultsareobtainedwiththeLaserMicrojet(LMJ),arevolutionarytechnologycouplingalaserandawaterjet.Itisfasterandcleanerthananyotherprocess,andgeneratesanimpressivekerfquality.Furthermore,itallowsfree-shapecutting,whichisimpossiblewithblades.Atlast,thesafetyquestionshouldnotbeforgotten.Infact,becauseofthewaterjet,notoxicarsenicgascouldbedetected.Keywords:Lasercutting,Waterjetguidedlaser,GaAs,Compoundsemiconductors,Chipping-freeINTRODUCTIONSiliconhasdominatedthesemiconductorwafermarketformorethanthreedecades.However,thecontinuingdemandsforhigherspeedandincreasingminiaturizationhavedriventhewirelessandbroadbandcommunicationsindustriestousethebrittleanddifficult-to-handle,butmuchfaster(meaninghighercarriermobility),III/Vsemiconductormaterials,suchasgalliumarsenide(GaAs)andindiumphosphide(InP).Indeed,thesematerials'electricalpropertiesgivethemseveralperformanceadvantagesoverpureSi,includinghighfrequencyoperation,improvedsignalreception,bettersignalprocessingincongestedfrequencybands,andgreaterpowerefficiency.AccordingtoICInsights,marketresearchfirmsbasedinScottsdale,Arizona,compoundsemiconductorICsarestilllargelybasedonGaAs,whichaccountedfor87%ofthemarketin2002.Mostofthebigplayersinthesemiconductormarkethaveturnedtheirproductioninthisdirection.ICInsightsexpectsthecompoundsemiconductorICmarkettoexperienceanaverageannualgrowthrateof22%from2002through2007.Incomparison,thetotalICmarketwillgrowatarateof10%overthesametimeperiod.ThecompoundsemiconductorICmarketpeakedat$2.42billionin2000,butfellto$1.69billionin2002.ICInsightsforecastsstronggrowthinthefollowingyears,withacontinualexpansionthrough2007,whenthemarketwillhavemorethandoubledto$4.65billion.TheGaAsmarketisnolongerconsideredanichemarket.Today,ifthemostimportantapplicationremainsthewirelesscommunicationindustry,GaAsisrevealingitspotentialinopto-electronicsforapplicationsinthemilitary,themedicalandespeciallytheLEDlightingdomains.Standardproductiontechnologiesstillneedtobecomemoreadaptedtothisnewhigh-growthmarket.Decreasingthechipsizebelow500pmrequiresusingwafersthinnerthan100|Jm;shrinkingthewafers'thicknessalsohavetheadvantageofloweringitstemperaturegradient.TheuseofGaAswafers,whichmightbeasthinas25“m,createsproblemswhentheyreachthelastleveloftheproductionchain-chipsingulation.BecauseGaAsisverybrittleandfragile,evenimprovedsawmethodsusingresinoidbladesdonotprovidethedesiredhighcuttingspeedandyield.Furthermore,consideringthatdicingistheverylastprocessofwafermanufacturing,whichmeansthatthewaferhasthehighestvalueatthatstage,andthedrivetowardhigherproductionvolumesatlowercosts,itisparamounttoemploythedicingmethodthatachievesthehighestyield.ItisalsoimportanttoconsiderthatalthoughGaAs'spriceisnotashighasitusedtobe,itisstillacostlymaterial.Anotherimportantaspectmustnotbeneglected:manufacturingandprocessingofcompoundsemiconductors,especiallyGaAs,revealsseriousindustrialsafetyconcernsbecauseofthehazardouschemicalcompoundsfoundincertainprocesses.PurecompoundGaAscontains51.8%wtarsenic.Itisdescribedastoxicbyinhalationandapossiblehumancarcinogen.Thesefactsraisealotofconcernsfromanenvironmental,healthandsafetystandpoint.COMPARISONOFTHEDIFFERENTDICINGMETHODSTherearecurrentlythreewell-knownmethodstodiceGaAswafers,namelytheabrasivesaw,scribingandbreaking,andlaserLMJdicingprocesses.BecauseofGaAs'sspecificproperties,disadvantagesofcertainmethodsthataretoleratedwhendicingSiwafersbecauseitisaratherforgivingmaterialbecomeunacceptabledisadvantageswhendicingGaAs.Traditionalsawingisthemostcommondicingtechniqueusedinthesemiconductorindustryingeneral.ItsprimaryadvantageontheSiwaferisthequalityofthekerf.ButthesawingprocessinducesmechanicalconstraintsthatarecriticalinthecaseofGaAs.IfchippingisacceptableforSi,itisnotthecaseforthisbrittlecompound.ChippingwidthsofGaAsbeinglarger,thestreethastobewidened,therebydiminishingthenumberofchipsperwafer.Also,becauseofthemechanicalconstraintsinducedbysawing,chipscornerstendtobreakeasilythusrenderingthepiecesunusable.Ingeneral,toachieveanacceptablecuttingquality,sawspeedhastobereducedtovaluesrangingbetween3and12mm/s,dependingonthewafer'sthickness,therebyconsiderablyslowingthewholeprocess.Table1showsacomparisonofthreedicingmethods.DicingmethodMinimalstreetwidthTimetoprocessawaferDiceshapelimitationMechanicalproblemsAbrasiveSaw80j,im50minutesLinearNosizelimitChippingBrokencomersScribeandBreak30minutesLinearAtleastlx1mmBrokenwalersLaserMicrojet40pm15minutesFree-shapcAtleast0.5x0.5mmNochippingNobrokencornersTabic1:ComparisonofthethreedicingmethodsforatypicalGaAswafer-400cuts,8inches,200pmthickWiththescribeandbreakmethod,streetwidthcanbereduceddrastically,increasingthenumberofdiesperwafer.Thisisarealadvantagewhenprocessinganexpensivecompoundmaterial.However,automationistoolowtoensureanacceptableyield.Forexample,wafersdonotalwaysbreakalongthescribedline.Thisoftenresultsintototalwaferbreakageandloss.Thismeansaswellthattheprocessingspeedisslow,andalargeamountofscrapwafersarerequiredforqualifications.UseoftheLaserMicrojet,nottobeconfusedwithastandardlaser,appreciablyincreasesthespeedandkerfqualityofGaAswaferdicing.Moreover,itallowsfree-shapecutting,includingmulti-projectwafers,whichisnotpossiblewithconventionalsawingtechniques.WATER-JETGUIDEDLASERPROCESSING

TheLaserMicrojet(LMJ)usesathinwaterjetasalight-guidetoguidethelaserontotheworkpiece(seeFig.1).Apartfromguidingthelaser,thewaterjetcoolsthepieceexactlyattheplacewhereitisbeingcutandheated,alsoremovingthemoltenmaterial.Infact,LMJisalow-temperaturelaserdicingsystemsincethemeasuredtemperatureduringanyworkingconditionsdoesnotexceed160°C[2].Wimlnw'Loser斤mJ?、加glensWimlnw'Loser斤mJ?、加glensLaserguidedbytotalinr^rttainflectifmWatercfuimbei-iiw'k/.Jfccelig.1-PrinctplcoftheLaserMierojctdicingicehniqucThelow-pressurejetalsoinsuresthatnomechanicalandnothermaldamagesareincurredbythewaferduringdicing(seeFig.2).TheLMJisthereforeparticularlyefficientonbrittleanddifficulttomachinematerialssuchasGaAs,evenforthicknessassmallas25pm.Furthermore,thehighlaminarityofthewaterjetprovidesaconstantkerfwidthequaltothediameterofthejet(25to75|Jmaccordingtothenozzlediameter).AnotherinterestingadvantageoftheLMJforthisspecificapplicationisthatitsspeedincreaseswhensamplesbecomethinner,whileinthecaseofsawing,itisjusttheopposite.ForthinGaAswafers,achievableLMJcuttingspeedsareveryhigh.ConventionallaserablationofGaAscreatesalotofdebris,hardtoremove,thatcanevendamagenearbyactivecomponents.WiththeLaserMicrojet(LMJ)technology,thisproblemhasbeenovercome.Usingaspecialthinwaterfilm,anewtechnologyspecifictoSynovaSAandtotheLMJ,keepsthewafercleanandfreeofparticles.Theresultinglevelofchipcontaminationisequivalenttoconventionalsaw,butthecutismuchfaster.Free-shapecutting,alsoknownasfree-formorarbitrarycutting,ofthinwafershasbecomeincreasinglyimportantforvariousapplicationsinmicroelectronicsandmedicine,inwhichchipswitharbitraryshapeareused.Conventionaltechniquescannotprovidetherequiredflexibilityandtwo-dimensionalfreedom.Fig.3presentsomni-directionalcuttingwiththeLMJ.TheGaAswafer(ontheleft)was178|Jmthick,andforakerfwitdhof75|Jm,achievedspeedwas15mm/s(thedotsonthesurfacearenotresiduesfromthecuttingprocess).TheInPwafer(ontheright)was250Jmthick,andresultingspeedwas2mm/s,singlepass.EmployingfrequencydoubledNd:YAGlasers,thecuttingspeedcouldsoonbeimproved.Fig.Omiii-direciioiiiilcutting,kerfwidth75pmFig.Omiii-direciioiiiilcutting,kerfwidth75pm-Left:GaAs(thedotspnthesuifacearenotresiduesfromthecuttingprocess)-Right:InPSAFETYRegardingsafetyissues,severaltestshavebeenperformedwiththeLMJ.ThemostimportantresultwasthatnoarsinegasisdetectedintheairwhilecuttingGaAswafers[3].,animportantdifferencetoclassicallasercutting(seeTable2).PELDetectedduringthetestRecommandationsArsinegas|ppmjTLV=0.05NotdetectedAirconcentrationofAs|pg/m>|10(OSHAcancerhazard)130(incuttingchamber4(outsidecuttingchamber)ExhaustsystemwithaparticulatefilterWaterconcentrationofAs[yg/L]<2062700Closedrecycling,ArsenicfilterArse