電子與通信工程專業(yè)英語(yǔ)Unit3IntegratedCircuit

IntegratedCircuitsareusuallycalledICsorchips.Theyarecomplexcircuitswhichhavebeenetchedontotinychipsofsemiconductor(silicon).Thechipispackagedinaplasticholderwithpinsspacedona0.1inch(2.54mm)gridwhichwillfittheholesonbreadboards[1].Veryfinewiresinsidethepackagelinkthechiptothepins.

1．Pinnumbers

Thepinsarenumberedanti-clockwisearoundtheIC(chip)startingnearthenotchordot.Fig3.1showsthenumberingfor8-pinand14-pinICs,buttheprincipleisthesameforallsizes.4．Datasheets

DatasheetsareavailableformostICsgivingdetailedinformationabouttheirratingsandfunctions.Insomecasesexamplecircuitsareshown.Thelargeamountofinformationwithsymbolsandabbreviationscanmakedatasheetsseemoverwhelmingtoabeginner,buttheyareworthreadingasyoubecomemoreconfidentbecausetheycontainagreatdealofusefulinformationformoreexperiencedusersdesigningandtestingcircuits.5．Sinkingandsourcingcurrent

Chipoutputsareoftensaidto“sink”or“source”current.Thetermsrefertothedirectionofthecurrentatthechip’soutput.

Ifthechipissinkingcurrentitisflowingintotheoutput.Thismeansthatadeviceconnectedbetweenthepositivesupply(+Vs)andthechipoutputwillbeswitchedonwhentheoutputislow(0

V).

Ifthechipissourcingcurrentitisflowingoutoftheoutput.Thismeansthatadeviceconnectedbetweenthechipoutputandthenegativesupply(0

V)willbeswitchedonwhentheoutputishigh(+Vs).Itispossibletoconnecttwodevicestoachipoutputsothatoneisonwhentheoutputislowandtheotherisonwhentheoutputishigh.ThisarrangementisusedintheLevelCrossingprojecttomaketheredLEDsflashalternately.

Themaximumsinkingandsourcingcurrentsforachipoutputareusuallythesamebuttherearesomeexceptions,forexample74LSTTLlogicchipscansinkuptol6

mAbutonlysource2

mA.6．The555and556timers

The8-pin555timerchipisusedinmanyprojects.apopularversionistheNE555.Mostcircuitswilljustspecify“555timerIC”andtheNE555issuitableforthese.The555output(pin3)cansinkandsourceupto200mA.ThisismorethanmostchipsanditissufficienttosupplyLEDs,relaycoilsandlowcurrentlamps.Toswitchlargercurrentsyoucanconnectatransistor.

The556isadualversionofthe555housedina14-pinpackage.Thetwotimerssharethesamepowersupplypins.7．LogicICs(chips)

LogicICsprocessdigitalsignalsandtherearemanydevices,includinglogicgates,flip-flops,shiftregisters,countersanddisplaydrivers.Theycanbesplitintotwogroupsaccordingtotheirpinarrangements:the4000seriesandthe74serieswhichconsistsofvariousfamiliessuchasthe74HC,74HCTand74LS.Formostnewprojectsthe74HCfamilyisthebestchoice.Theolder4000seriesistheonlyfamilywhichworkswithasupplyvoltageofmorethan6

V.The74LSand74HCTfamiliesrequirea5

Vsupplysotheyarenotconvenientforbatteryoperation.8．PlCmicrocontrollers

APICisaProgrammableIntegratedCircuitmicrocontroller,a“computer-on-a-chip”.TheyhaveaprocessorandmemorytorunaprogramrespondingtoinputsandcontrollingoutputssotheycaneasilyachievecomplexfunctionswhichwouldrequireseveralconventionalICs[2].

ProgrammingaPICmicrocontrollermayseemdauntingtoabeginnerbutthereareanumberofsystemsdesignedtomakethiseasy.ThePICAXEsystemisanexcellentexamplebecauseitusesastandardcomputertoprogram(andre-program)thePICs;nospecialistequipmentisrequiredotherthanalow-costdownloadlead.ProgramscanbewritteninasimpleversionofBASICorusingaflowchart.ThePICAXEprogrammingsoftwareandextensivedocumentationisavailabletodownloadfreeofcharge,makingthesystemidealforeducationandusersathome.IfyouthinkPICsarenotforyoubecauseyouhaveneverwrittenacomputerprogram,pleaselookatthePICAXEsystem!ItisveryeasytogetstartedusingafewsimpleBASICcommandsandthereareanumberofprojectsavailableaskitswhichareidealforbeginners.NEWWORDSANDPHRASES

integrate vt. 使結(jié)合成為整體

notch n. (邊緣或表面上的)V形痕跡，刻痕

vi. 在(事物)上刻V形痕

semiconductor n. 半導(dǎo)體

grid n.格子，格欄；地圖上的坐標(biāo)方格；輸電網(wǎng)

anti-clockwise adj. 逆時(shí)針?lè)较虻?/p>

screwdriver n. 螺絲刀；螺絲起子；改錐

antistatic adj. 抗靜電的

aluminium n. 鋁beetchedonto n. 被……蝕刻

bepackagedin n. 被……包裝

besolderedonto n. 被……焊接

NOTES

[1]Thechipispackagedinaplasticholderwithpinsspacedona0.1inch(2.54mm)gridwhichwillfittheholesonbreadboards.

句中“spacedona0.1inch(2.54mm)grid…”作為后置定語(yǔ)修飾“pins”?！癰readboard”為做電路實(shí)驗(yàn)時(shí)用的面包板，可在上面直接插上元器件和導(dǎo)線組成簡(jiǎn)單的實(shí)驗(yàn)電路。

本句可譯為：芯片被封裝在帶有引腳的塑料插座中，每個(gè)引腳間隔0.1英寸(2.54mm)，可插在電路試驗(yàn)板上。[2]TheyhaveaprocessorandmemorytorunaprogramrespondingtoinputsandcontrollingoutputssotheycaneasilyachievecomplexfunctionswhichwouldrequireseveralconventionalICs.

句中“They”指的是PIC，動(dòng)名詞短語(yǔ)“respondingtoinputs”作為后置定語(yǔ)修飾“aprogram”。

本句可譯為：PIC內(nèi)含一個(gè)處理器和存儲(chǔ)器，可根據(jù)輸入來(lái)運(yùn)行程序從而控制輸出。因此它們能夠很容易地完成一些需多個(gè)傳統(tǒng)集成電路芯片才能實(shí)現(xiàn)的復(fù)雜功能。

EXERCISES

I．TranslatethefollowingphrasesintoChinese.

(1)

IntegratedCircuits (2)

DualIn-Line

(3)

sinkcurrent (4)

sourcecurrent

(5)

LevelCrossingproject (6)

flip-flops

(7)

shiftregister (8)

ProgrammableIntegratedCircuit

(9)

computer-on-a-chip

II．TranslatethefollowingparagraphsintoChinese.

(1)

ManyICsarestaticsensitiveandcanbedamagedwhenyoutouchthembecauseyourbodymayhavebecomechargedwithstaticelectricity,fromyourclothesforexample.StaticsensitiveICswillbesuppliedinantistaticpackagingwithawarninglabelandtheyshouldbeleftinthispackaginguntilyouarereadytousethem.

(2)

LogicICsprocessdigitalsignalsandtherearemanydevices,includinglogicgates,flip-flops,shiftregisters,countersanddisplaydrivers.Theycanbesplitintotwogroupsaccordingtotheirpinarrangements:the4000seriesandthe74serieswhichconsistsofvariousfamiliessuchasthe74HC,74HCTand74LS.

參考譯文

第三單元集成電路

集成電路通常被稱為IC或芯片。它們是被固化在微小的半導(dǎo)體(硅)芯片中的復(fù)雜電路。芯片被封裝在帶有引腳的塑料插座中，每個(gè)引腳間隔0.1英寸(2.54

mm)，可插在電路試驗(yàn)板上。在插座下有一些非常精細(xì)的導(dǎo)線，(通過(guò)它們)將芯片與引腳相連。

1．引腳編號(hào)

集成電路芯片的引腳編號(hào)從靠近槽口或圓點(diǎn)處開始以逆時(shí)針?lè)较蚺帕校瑘D3.1所示為一個(gè)8腳和14腳的集成電路芯片。對(duì)于其他數(shù)量引腳的芯片，編號(hào)的規(guī)則都是一樣的。

2．芯片插座(雙列直插式插座)

集成電路芯片很容易被焊接時(shí)的熱量所損壞，并且它們的短引腳不受散熱片保護(hù)。因此我們采用芯片座作為替代，嚴(yán)格地說(shuō)叫雙列直插式(DIL，DualIn-Line)插座，它可安全地被焊接到電路板上。當(dāng)所有的焊接工作完成后，再把芯片嵌入到插座中。

僅在焊接時(shí)才使用芯片插座，在電路試驗(yàn)板上是不使用它們的。商業(yè)上生產(chǎn)的電路板通常是在沒(méi)有芯片插座的情況下直接將芯片焊接到電路板上的，通常這項(xiàng)工作都是由運(yùn)轉(zhuǎn)快速的機(jī)械設(shè)備完成的。不要試圖自己去這樣做，因?yàn)槟愫芸赡軙?huì)損壞芯片，而且通過(guò)拆焊移出芯片時(shí)不可避免地會(huì)損壞它。

如果需要將芯片移出，可用小平口螺絲刀將它從插座中輕輕地拿出。先將螺絲刀的平口插入芯片和插座，然后輕輕地轉(zhuǎn)動(dòng)螺絲刀從而將芯片的兩端小心地、水平地抬起。在試圖將芯片移出前要小心地將芯片的兩端抬起，否則會(huì)將引腳弄彎或者弄斷。3．靜電保護(hù)

許多集成電路都對(duì)靜電敏感，當(dāng)你接觸時(shí)可能會(huì)損壞它們，因?yàn)槟愕囊路赡茏屇愕纳眢w帶靜電。靜電敏感的集成電路會(huì)被放置在帶有警告標(biāo)簽的靜電保護(hù)袋中，不使用時(shí)必須把它們放置在袋中。

一般在你接觸集成電路前，先將你的手與金屬水管或窗框接觸，達(dá)到接地的效果就足夠了。但是對(duì)于更為敏感(且昂貴的)的集成電路可利用特殊的裝置。這些裝置包括接地手環(huán)和接地工作臺(tái)。你可取一塊廚房用的鋁金屬薄片，然后用鱷魚嘴夾通過(guò)串聯(lián)一個(gè)10k的電阻將它接到金屬水管或窗框上，這樣就可制成一個(gè)接地工作臺(tái)了。4．?dāng)?shù)據(jù)手冊(cè)

大多數(shù)的集成電路都附有數(shù)據(jù)手冊(cè)，提供產(chǎn)品等級(jí)和功能方面的詳細(xì)信息，有時(shí)還給出參考電路。數(shù)據(jù)手冊(cè)中大量帶有符號(hào)和縮寫的信息，初學(xué)者感到難以理解。但對(duì)于有經(jīng)驗(yàn)的使用者來(lái)說(shuō)，數(shù)據(jù)手冊(cè)值得一看，因?yàn)樗舜罅康挠杏眯畔⒓霸O(shè)計(jì)和測(cè)試電路。5．灌電流和拉電流

芯片的輸出通常被稱為“灌”或“拉”電流。它們表示了芯片輸出端電流的方向。

如果芯片是灌電流式的，那么電流流入輸出端。這就意味著在輸出端為低電壓(0

V)時(shí)如果將一個(gè)器件連接在正電源和芯片的輸出端之間，那么這個(gè)器件將會(huì)被導(dǎo)通。

如果芯片是拉電流式的，那么電流流出輸出端。這就意味著在輸出端為高電壓(+V)時(shí)如果將一個(gè)器件連接在負(fù)電源和芯片的輸出端之間，那么這個(gè)器件將會(huì)被導(dǎo)通?？梢酝瑫r(shí)將兩個(gè)器件接到芯片的輸出端，其中一個(gè)當(dāng)輸出低電壓時(shí)是通的，另一個(gè)當(dāng)輸出高電壓時(shí)是通的。這種設(shè)計(jì)方式用于平交路口信號(hào)燈項(xiàng)目中用來(lái)使紅色的發(fā)光二極管交替閃爍。

芯片輸出的最大拉電流和灌電流通常一樣大，但也有些例外，如74LSTTL邏輯芯片能夠提供高達(dá)16

mA的灌電流，但拉電流只有2

mA。6．555和556定時(shí)器

8腳的555定時(shí)器芯片應(yīng)用于許多項(xiàng)目中，常用的型號(hào)為NE555。大多數(shù)電路指定使用“555集成電路芯片”，NE555就適用于這種情況。555的輸出引腳3的拉電流和灌電流可達(dá)200

mA。這比大多數(shù)的芯片都大，而且足夠驅(qū)動(dòng)發(fā)光二極管、繼電器線圈和低電流電燈。需產(chǎn)生大電流時(shí)，可連接一個(gè)晶體管來(lái)放大電流。

556是兩個(gè)555的組合，14腳封裝。556內(nèi)的兩個(gè)定時(shí)器共享一個(gè)電源腳。7．邏輯集成芯片

邏輯集成芯片處理數(shù)字信號(hào)，這種器件有很多種，包括邏輯門、觸發(fā)器、移位寄存器、計(jì)數(shù)器和顯示驅(qū)動(dòng)器等。根據(jù)它們引腳的排列方式分為兩類，即4000系列和74系列，74系列又分為許多子類，如74HC、74HCT和74LS。

對(duì)于大多數(shù)新的項(xiàng)目，74HC系列是最佳的選擇。較早的4000系列是工作電壓唯一在6

V以上的系列。74LS和74HCT系列需要5

V電源，因此它們不便于用電池來(lái)驅(qū)動(dòng)。8．可編程集成電路微控制器

PIC就是可編程集成電路微控制器，即一個(gè)“片上計(jì)算機(jī)系統(tǒng)”。PIC內(nèi)含一個(gè)處理器和存儲(chǔ)器，可根據(jù)輸入來(lái)運(yùn)行程序從而控制輸出。因此它們能夠很容易地完成一些需多個(gè)傳統(tǒng)集成電路芯片才能實(shí)現(xiàn)的復(fù)雜功能。

對(duì)于初學(xué)者來(lái)說(shuō)，可編程集成電路微控制器的編程是非常難的，但是現(xiàn)在有許多使這個(gè)過(guò)程簡(jiǎn)化的系統(tǒng)。PICAXE就是一個(gè)很好的例子，因?yàn)樗褂脴?biāo)準(zhǔn)的計(jì)算機(jī)對(duì)PIC編程。除了廉價(jià)的下載數(shù)據(jù)線外，它不再需要其他專門的設(shè)備。程序可使用簡(jiǎn)單版本的BASIC編寫或使用流程圖編寫。由于PICAXE編程軟件和大量的文件可免費(fèi)下載，對(duì)于教學(xué)和家庭用戶這個(gè)系統(tǒng)是非常理想的。

如果你從未編寫過(guò)程序，認(rèn)為PIC不適合你，那么請(qǐng)看PICAXE系統(tǒng)！使用一些簡(jiǎn)單的BASIC命令很容易入門，并且還有許多對(duì)初學(xué)者非常理想的案例可作為參考。

EXTENSIVETEXT

HowICProductsAreMade?

TheIntegratedCircuit(IC),atechnologicalwizard,haschangedtheworld,ourlifeandourcivilizationtosuchanextentthatthepresenthumansocietyexistsdirectlyandindirectlyrelyingonICproducts.Themoreadvancedthesocietyis,themoredependentonICitappears.InsomedevelopedcountriessuchastheUnitedStatesandJapan.ICmanufacturinghasbecomeamajorindustryunderlyingthenations’economyNomodemproductcanbemadewithouttheparticipationofICproducts.Therefore,IChasbecomeapillarsupportingourmoderncivilization.

HowisanICproductmade?StudyingtheprocessesinvolvedinICmanufacturingisjustaninterestingsubjectforeveryuniversitystudentmajoringinscienceandtechnology.

Therawmaterialformakingsemiconductorproductsispolycrystallinesilicon,whosepurityisrequiredtobeabove99.9999%.Impurity-freeisessentialtothesuccessofIC-making.Theworkingenvironmentmustbemaintaineddust-freeandoperatorsmustwearoverallslopsanddongloves.Allrawmaterials,solvents,workingmedia，fluidsforflushingintermediateproducts,tools,containersandmachinesmustbefreefromfreemetallicionsandotherimpuritiesthatwouldentertheICproducts.

Thefirststepispreparingsingle-crystallinesiliconsubstrates,duringwhichthepolycrystallinesiliconisfirstcrystallizedintosingle-crystalsiliconrodsinacrystal-pullingfurnace,inwhosevacuumchamberagrainofsiliconcrystalioniskeptturninganddrawnupwardslowly.Fromthesurfaceofthemoltenpolycrystallinesilicon,inseveralhoursofprocessing,arodofsingle-crystallinesiliconwillgrowafterthecrystalLon,inotherwords,itwillcrystallizewiththesamecrystallineasthecrystalLon’s.Thenthesingle-crystallinesiliconrodisslicedonaspecialmachinebyanon-metallicdiskwithdiamondsonitsedge.Thesliceswillbepolishedwithcrystolonpowderuntiltheirsurfacebecomesamirrorlikefine.

Onthesiliconsubstrateanepitomicallayerismade,whereICcomponentsareformedsubsequently.InaCVD(chemicalvapordeposition)process,thesiliconsubstratesplacedinavacuumcrystaltubearefirstheatedto1,600℃byhigh-frequencyradiopowerandthenSiH2C12andcertaingaseouscompoundsofAs(arsenic)orP(phosphorus)isinjectedintothetubetomakeadepositofseveralurnontheirsurface.IonsofAsorPareimpuritydeliberatelyaddedtothesingle-crystallinesiliconstructuretosupplyelectronsthattransmit“negative”currentinthesiliconcrystals,whichiscalledn-typesilicon.B(boron)canbeaddedasimpuritytoproducep-typesiliconthatsuppliesholesfortransmitting“positive”current.Whetherap-typeorann-typesiliconsubstrateisneededdependsonwhattypeoftransistorsisexpectedtobemanufacturedonit:n-p-ntypeorp-n-ptype.Anotherpreparationismakingaseriesofmasksonwhichmicrocircuitpatternsaredescribed.Eachmaskisusedto“print”,thespecificmicrocircuitpatternontothesiliconsubstrateinaprocessknownasthephotolithography.Thesizeofeachmaskisbigenoughtocoverthesiliconslice.Usually,theyaremadeofcellulosefilmormetalfilm.

Tomakethosemasks,firstacircuitpatternisdesignedtodescribethephysicalstructureofthecircuitunit,whichmayconsistdozensoftransistorsandresistorsaswellasconnectingwires.Eachbipolar-typetransistorhasanemitter,acollectorandabase,andaMOStransistorhasthreeelectrodes:source,drainandgate,allmadeinasinglewaferofsilicon.Resistorscanbemadeinalmostthesamewayastransistors.Then,takingintoaccounttheprocessinwhichthestructureofthosetransistorscanbeproduced,aseriesofpatternsformakingasinglecircuitunitonthesubstratecanbedrawneitherbyhandorbyacomputer-aidedgraphicsplotter.Thesepatternsareminiaturedusingspecialcamerashavinghighresolvingpower.Further,eachpatternisduplicatedusingalaser-positioningcameratoproduceanarrayofthesamepatternonafilms,onwhicheachelementofthatarrayhasexactlythesamepatternandtheyseparatefromeachotherwithexactlythesamedistance,inotherwords,theyarealignedonrowsandcolumnswithhighprecision.Precisionoftheirrelativepositiononthefilmisofparticularimportancebecausethemaskssomadewithmanypatternsoneachcanguaranteeprecisepinpointingofallpatternsonthesiliconsubstrateduringthephoto-lithographprocess.Finally,thefilmisfurtherminimized.

ThephotolithographyprocesswillberepeatedlyinvolvedinmakingICproducts,withtheprocessas:(1)

Onthefilmtobeprocessed,phenolnovolacsystemresinandphoto-resistareappliedinuniformthickness.

(2)

Photo-maskengravedwithdesiredcircuitpatternsisplacedonthephoto-resistlayerforexposuretolight;thepartoftheresistexposedtolightisphoto-decomposed.

(3)

Whenthesubstrateissoakedinalkalineliquid,thosepartswhichhavephoto-decomposedarewashedaway,leavingapatternontheresistlayer.

(4)

Theoriginalfilmtobeprocessedbyetchingusingphoto-resistasamaskisremovedfromthepatternarea.(5)

Whentheresistmaskisremoved,theoriginalfilmtobeprocessedremainsasthatcontainingcircuitpatterns.

ThefollowingdescriptionprovidesyouwithknowledgeofthesimplifiedprocessesinvolvedinmakingaMOStransistor.Actually,alltransistorsonasinglesiliconsubstratearemadesimultaneouslyduringthoseprocesses.

(1)

Amirror-polishedsingle-crystalsiliconsubstratesurfaceisheatedto900to1,000℃inanoxidationatmosphereforoxidationofthesurface,sothatanapproximately0.005-μm-thickSiO2filmisgenerated.LaminatingtheSiO2film,Si3N4filmisdepositedbyaCVDprocessinwhichSiH2C12(dichloridesilane)andNH2(ammonium)reactat700to800℃toforma0.1-m-thickfilmontheareawherethetransistorismanufactured.Therestoftheareaiscalledelementseparationdomain,whichhorizontallyseparatestransistordomainsfromeachother.

(2)Thesubstrateisexposedagaininahigh-temperatureoxidationatmospherefortheseparationareatobeselectivelyoxidizedtoform1-m-thickoxidefilms.Si3N4filmactsasamasktodeterminetheboundaryseparatingthetransistordomainfromtheseparationarea.(3)

RemainingSi3N4filmandsiliconoxidefilmundertheSi3N4areremoved.Next,0.02to0.03-m-thickgateoxidefilmisdepositedonthesurfaceofthesiliconsubstrateinthetransistordomainbyathermaloxidationprocess.

(4)

ACVDprocessbywhichsilane(Si3N4)isdecomposedat650℃isappliedfordepositing0.3to0.5-μm-thickpolycrystallinesiliconontheentiresurfaceofthedomain.Crystallizedpolycrystallinesiliconshowshighresistancecharacteristicsasitis,soAsorPisaddedasimpuritytosupplyelectronsascarriersofnegativecurrentinsiliconcrystals.Foraddingimpurity,theimpurityisionizedtoformanionbeam,whichisthenacceleratedbyanelectricfieldinvacuumandinjectedbyanioninjectionprocess.Finally,SiO2filmisprocessedintothepatternofagateelectrode.

(5)

Atstage(4),ofasioninjectionprocess,asionsreachthesiliconsurfaceunderthethingateoxidefilmtogeneratesourceanddrainelectrodes.Inthiscases,AsionsonlyreachareasofthesourceanddrainelectrodedomainbecausetheyarehinderedfromreachingthesiliconsurfacebythickSiO2filmcoveringallbutthetransistordomain.Stages(1)to(5)formthebasicprocessbywhichaMOStransistorismanufactured.Whenalargenumberoftransistorsinacircuitunitareconnectedbyaluminumwiringinaspecificarea,manufacturingofanICproductiscompleted,exceptthefollowingadditionalprocess.

(6)

Toseparatetheelectrodesoftransistorsfromthewiringlayers,aninsulationlayerisdeposited.ThematerialsaresiliconoxideandPSG(phospho-silicateglass)obtainedbyapplicationofaCVDprocessusingsilaneandoxygenaddedwithphosphine(PH3),PSGshowsliquidityat1,000℃toformsmoothsurface.(7)

ContactholeswhichreachthesurfaceofbothsourceanddrainelectrodesaremadethroughthePSGlayer.

(8)

Finally,a1-m-thickaluminumlayerisdepositedovertheentireareatomakewiringwithPVD(physicalvapordeposition)methodssuchassputtering.

ThefollowingtopicsareofparticularsignificanceinICmanufacturing.AnobvioustrendinICmanufacturingistheever-increasingintegrationoftransistorsinanICproduct.WhenthenumberoftransistorsintegratedinanICproductexceeds100k,theproductiscalledlarge-scaleintegrated(LSI)circuit.ThelargerthecapacityofanLSIproductthehigheritscost-effect.ThequalifierrateofanLSIproductisanessentialfactorthatdetermineswhetherthatproductcansurvive.Thedecisivefactorsthatdeterminequalifierrateincludethepurityofrawmaterials,thecleannessoftheworkingenvironment,theprecisionofthemanufacturingequipmentandtheadvancementofprocessingtechniquesused,