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BIPOLAR TECHNOLOGY The Bipolar Integrated Circuits Principles and Manufacturing version 2.2 En VPS This presentation was prepared for the needs of the company ON Semiconductor with the aim to approximate the production principle of bipolar integrated circuits especially to those who have never met this topic. The author, VPS s.r.o. thanks to TESLA SEZAM, a.s., TEROSIL, a.s. and SCG Czech Design Center s.r.o. based in Roznov pod Radhostem, Czech Republic for their friendly help in compiling the presentation and for the chance to shoot the video clips in the production rooms. In our effort to continuously improve our products we thank you in advance for your comments, which will help us in the production of further versions.. Piestany, June 2001 VPS s.r.o., P.O. Box B-11, Partizanska 31, 921 01 Piestany 1, Slovak Republic tel., fax.: +421 838 7730151, email: [email protected] Bipolar Technology 2.2 En 2 Controlling the Presentation Mouse Control Video A click of the left mouse button, unless the cursor is on a control button or on a video, moves the presentation one step forward. If there is a video on the slide, it is in the blue frame, similarly to the picture below. By locating the cursor on the video, the shape of the cursor will change to character. Clicking on the left mouse button will start the video. Clicking the left mouse on the running video will stop it. Keyboard Control The N key has the same function as the left mouse button (independent of the cursor position). The P key has the opposite function, it means one step backward. Press Esc to finish the presentation. Control Buttons on the Picture By locating the cursor on a button, the shape of the cursor will be changed into character. Clicking the left mouse will stimulate its function then. transition to the slide Contents return to the last displayed slide transition to a slide with relevant information next slide Bipolar Technology 2.2 En end of presentation VIDEO 320 x 240 If you do not notice an animation action press the P key (Previous) and then start the animation with the N key (Next). 3 Contents Introduction Voltage Regulator Where Else it can be Used? What is Inside an Integrated Circuit? Semiconductor Silicon - the Structure Silicon - Inside the Single Crystal Silicon - Conductivity Type Silicon - PN Junction - Bipolar Technology Diode Function Transistor Function (NPN) Silicon Wafer Why is it “integrated”? Surface of a Chip Is the Whole Thickness of a Chip Utilized? What is Under the Surface? Cross Section How it Originates? Buried Layer Collector Second Part of Insulation and the Base Emitter Contacts and Metallization Passivation Final Wafer Treatment Testing Assembly Bipolar Technology 2.2 En Clicking on this box will navigate you to the Controlling the Presentation slide Thermal Oxidation Oxidation (diffusion) Furnace Oxidation Furnace - Gas System Diffusion Diffusion Furnace - Gas System Photolithography and Etching Plasma Etching Ion Implantation Ion Implanter Epitaxy Epitaxial Reactor Sputtering Contamination Silicon Fragment Clean Rooms Semiconductor Hygiene and Wafer Handling Process Control Materials for the Semiconductor Technology Reverse Osmosis Diffusion - the Principle Gas Flow Measurement Anisotropic and Isotropic Etching Names of the Layers Some Physical Units 4 Introduction The Roznov pod Radhostem, Czech Republic manufacturing location is a significant European source of semiconductor devices. Voltage regulators, operational amplifiers and various control circuits are designed and manufactured there in the high tech clean rooms. The voltage regulator MC 7812 in TO220 case is a typical product from Roznov. It was used as an example of bipolar analog integrated circuits. Bipolar Technology 2.2 En 5 Voltage Regulator There The To have course is aa stable well-known of an supply unstable variant (insupply order of the the voltage stabilized light is bulb represented does voltage notsupply blink), onon the a voltage the diagram left bottom stabilizer, - the picture. light e.g. bulb theis blinking. The integrated circuit mostMC of 7812, electrical hasappliances to be used.could not work reliably powered like this. 16 14 Voltage [V] 12 10 8 6 4 2 0 Time MC 7812 Bipolar Technology 2.2 En 6 Where Else it can be Used? The voltage Wherever This is the amotherboard stable regulators supply are with isnot necessary. a only microprocessor. in the Oncentral the picture The power microprocessor, supply we canbut, seeaccording a just personal as many tocomputer theother requirements, parts, wellknown needs also at ato different stable everybody. supply places There voltage of particular arefor several itsboards. functioning. boards with many parts inside the computer. Bipolar Technology 2.2 En 7 What is Inside an Integrated Circuit? The If This webasic small remove material piece the of black of matter a material chip is is called a from chip. the semiconductor - silicon. package, After an enlargement we can see we the can leads see leading its up to a small piece of matter inside which the structure. whole function of a regulator proceeds. Bipolar Technology 2.2 En 8 Semiconductor Electrically Nonconductive Materials - insulators glass china plastics . . . Conductivity From Nonconductive Conductive Finally the there view materials of are of the materials semiconductors, electric semiconductors - conductors conductivity - insulators having - can especially -the e.g. be their materials glass, can beplastic, china, metals, electrical influenced divided but conductivity by also temperature, wood, asgraphite follows: etc. between Their and electric some "nonconductivity" that field of others. anand insulator Their can be influenced conductivity and especially conductor. bycan avery tiny This beslightly amount partially can beonly. substantially of influenced, foreign materials. mainly influenced by These admixtures calledgermanium dopants, could temperature. in a wide range. Silicon, and be galliumarsenide chemical elements arelike theboron, well-known phosphorus, semiconductors, arsenic silicon or antimony... is the most commonly used one. Electrically Conductive Materials - conductors silver copper gold . aluminum iron . graphite Semiconductors Influenced by temperature, electric field or by an impurity of foreign material the semiconductor can behave once as an insulator yet as a conductor. Bipolar Technology 2.2 En silicon germanium galliumarsenide 9 Silicon - the Structure It is The If Each wenecessary basic basis move silicon material of aatom acopy silicon to add has of this a crystallographic that four voltage structure silicon neighbors, regulator has by 1/4 structure which chip of the itis silicon. is internal forms appropriate a face aSilicon diagonal, bond centered properties with. is aboth cubic chemical for the structure semiconductor original element -and a from cube thechips the with groupwhen atoms shifted only IV in atoms its inthe the vertices form atoms Periodic aand diamond in the table. in the whole type wallvolume of centers. the of the structure, chip are arranged which is exactly the silicon according structure to as thiswell. structure. Such and arrangement is called single crystal. A view of a fictitious observer inside the silicon single crystal looks like the following picture. 28,0885 Si 14 2,33 g/cm3 Silicon Bipolar Technology 2.2 En 10 Silicon - Inside the Single Crystal Bipolar Technology 2.2 En 11 Silicon - Conductivity Type Ontechnology, An Physically, Only Such In admixture the aa very pictures, slight the tiny amount of we boron amount some the usually P-type admixture ischemical difficult ofknow asilicon dopant a to causes elements low formulate will isdoped be sufficient a represented different - dopants, in silicon grams, formechanism -doping can up by therefore to, a silicon. shade say,of1018 the of substantially electric For unit atoms blue, example, ofthe acurrent of dopant N-type dopant/cm3 influence 1 transfer gram concentration silicon of and the by in phosphorus silicon asilicon a heavy shade used than electric doped ofin (on red. phosphorus thethe conductivity. silicon semiconductor Deeper pan -ofwith shades or scales) arsenic. Boron, higher technology will is Silicon phosphorus doped sufficient is concentration represent the number with to a boron change higher and of a arsenic dopant isdopant. concentration 1000 called atoms are tons the This especially P-type of per heavy silicon ofunit a dopant. silicon doped used volume, (a fullwhile for silicon train) usually this silicon into is purpose. called given the doped N-type P+ in with or 3 or phosphorus one. #atoms/cm N+ type silicon. of silicon. arsenic The is called concentration the N-typeofone. 1g phosphorus per 1000 tones of silicon is 45000000000000 atoms/cm3 of silicon. 1 gram of phosphorus in 1000 tons of silicon = 45 000 000 000 000 phosphorus atoms in 1 cubic centimeter of silicon conductivity conductivity P N (4,5 . 1013 cm-3) 10,81 heavy doped silicon tens - hundreds kg / 1000 tons 5B (1018 to 1021 cm-3) Boron P+ , N+ Bipolar Technology 2.2 En (Positive) (Negative) 30,97376 15 P 74,9216 Phosphorus 33 As Arsenic 12 Silicon - PN Junction - Bipolar Technology A two-layer The interface diode between and three-layer P-type andtransistor N-type layers are the of silicon, bestcalled PN devices. junction, an exceptional knownthe bipolar Thehas bipolar transistors physical are classified behavior. as either NPN Semiconductor or PNP according devicestowhich the arrangement function is based of the on PN junction interfacing semiconductor are bipolar layers. devices and their manufacturing technology is called bipolar technology. P PN Junction Transistor PNP N P N P N P Diode Transistor NPN Anode Collector Base N P N Cathode Emitter Bipolar Technology 2.2 En 13 Diode Function Now, we Diode is aconnect simple the PN cathode junction. to Onthe thebattery picture, negative the diodeand pole is connected the anode to through a circuit thewith bulb a light to thebulb positive and battery. one. TheWhen diodethe conducts P layerelectric - anodecurrent - is connected and the bulb through The shines. the light diodebulb conducts to the battery electric negative current only pole, if the there is negative battery no electric pole current is connected flowing through to the N-layer, the circuit. The bulb does not shine. cathode. IA = 2 0A Anode P Cathode N + Keyboard P Bipolar Technology 2.2 En N 14 Transistor Function (NPN) Transistor, On There Now, Let´s the we move ispicture, are still connect different inano his sleeve the current principle, a kinds transistor small on flowing the of watch isdiodes resistor created is into connected battery and the now. bybase. transistors. to three The the to aIn base layers. circuit the There with collector circuit. resistance From athe battery isThere acircuit, big thin is reduced ones is and (1-3 athere small, aused mm) bulb. and islayer say, to no The the control current 10 of base bulb mA a P-type engines is current as current connected well. base to doubles. flowing The thebulb to a between collector does into A ones response the notbase. we can -two shine. it in isfind N-type Physical the inIfcollector on we collector layers. the compare processes voltage circuit. circuit Thethe N-type regulator Amakes in transistor resistor semiconductor layers the chip. isto bulb are a called fully. connected water layers shine tap, the cause emitter this to Similar athe situation much base. and to an bigger the represents open collector, current valve.athe flow By closed P-type aalso transistor valve. inlayer the is called collector we can regulate the circuit. base. In bigThe comparison changes arrangement oftocollector theinwater this current way main, isby the the NPN transistor. valve means isof half-opened. small changes of the base current. Transistor works as an amplifier. ICK = 2 0A 1 R = 40 80 W IB = 20 0 mA 10 mA N P N + Base thickness 1-3 µm Keyboard P Bipolar Technology 2.2 En N 15 Silicon Wafer Secondary Flat VIDEO 320 x 240 P <100> <100> Primary Flat diameter: 100 mm, thickness: 525 µm <111> On integrated An For The the that silicon crystallographic conductivity wafers video, reason, wafer arecircuit there fabricated many (P is or round-shaped. are chip orientation, N) chips some is type byvery are cutting scenes and small, processed in aThe respect from silicon from just diameters athe to awafer few the square together of crystallographic monocrystalline silicon 100,wafers wafer millimeters. 125, in one 150 surface, manufacturing slice orientation silicon mm Itof or would iscylinder semiconductor important more are be line. are difficult, encoded pulled commonly for the from -ifsilicon in final not amolten used. even impossible, wafer. A electrical relative silicon 100 mm At inposition special the properties. wafer toend produce of equipment. is ofprimary about the In each practice, process half and The chip ofsecondary millimeter the melting individually. wafer orientations point is flat thick. cut on ofup into individual Already according each silicon wafer. isthe 1415 towafer The the chips. °Ctop pictures (in material side comparison of are issilicon doped usedtowafer and iron andthey with1535 itisishighly are P or N-type classified polished. °C or aluminium then. as <111> withor660 <100>. °C). Bipolar Technology 2.2 En 16 Why is it “integrated”? All the The voltage components regulator of is a an regulator electronic are circuit the blueprint matched - integrated of which-we intocan onesee chip. in the This is background. why the final On device the is chip, called we can identify integrated circuit. particular terminals as well as various devices - transistor, resistor, capacitor ... Bipolar Technology 2.2 En 17 In our conception Details According of atochip the structure blueprint, the transistor cannot we can consists be identify seenofwith a3 the naked collector, silicon layers an eye. emitter and Wewe need and canaahardly base microscope on findthe such witha at least tenfold microphotograph. structure on the magnification. picture. The Q8 Therefore transistors When looking it iscovers at the area necessary chip surface, of to 145 analyze x only 80 µm. the some under complex surface of lanes space. can be seen. The whole secret of the circuit function is deeper in its structure. According to the blueprint, there should be many various components there, especially transistors. Let´s choose the, say, Q8 transistor and let´s investigate its structure. Collector Emitter Base Collector N P N Emitter Base 80 µm Surface of a Chip Q8 145 µm Where this structure is? Bipolar Technology 2.2 En 18 Is the Whole Thickness of a Chip Utilized? vertical : horizontal 1 : 1 20 µm 80 µm 340 µm vertical : horizontal 5 : 1 Because The Q8 transistor layer of with thisalldimensional the covers integrated an area disproportion circuit of 145 x 80 in µm. The thickness components horizontal (145 reaches x 80ofµm) finalized justand 20 µm vertical chip under is (5 340 the toµm. 20 (Let´s surface. µm) directions remind Moreover, that the the structure many silicon details cross wafer are sections thickness in the is 525 upper are represented 5µm. µmThe only.wafer in theisway finished of thebyquintuple grinding at the of scale end theofvertical a manufacturing dimensionprocess.) in comparison to the horizontal one. 145 µm Bipolar Technology 2.2 En 19 What is Under the Surface? In order Now, To The On this improve the this integrated transistor buried NPN P-type last we layer PN surface, picture, to layer can transistor image interface, layer the region there see of structure circuit collector the there the prevents inward the are isstructure consists transistor close there structure consists P+ are ischaracteristics, the type metal built the under is of cell is atransistor walls is of in relatively 3imaged connections the with many layers: the a better dividing emitter. surface N-type the at from the N-type thick whole way, thechip the in a components. silicon chip we transistor N+ mutual collector, surface forming order same will type into to scale layer use influencing is the enable region the P-type structure. connected atransistor both (the cells bigger Informing the order base red infor by horizontal transistor We enlargement layer) particular to "leakage" base. not and the the can toN-type on cell buried see be to and the components bottom. the of "communicate" the and emitter. P-type vertical electric layer components insulation we Since by silicon will Here, an ofitNundesirably substrate integrated make reaching is current the type with directions incollector depth, other column. the under down silicon (the and components circuit. itinfluenced isisthe blue itformed to called represents layers These the insulation. layer). P-type the by one on transparent. walls the buried the another, the silicon N-type chip. are real layer. called substrate. proportion there siliconmustof be some insulation. limited Q8 transistor. byindependent the insulation areas fromon sides the and chip,bya the kind of cells.layer buried Let´sfrom have bottom. a look at the cell of "our" Q8 transistor. Emitter Base Collector N P N N-type layer Collector N P-type pad Emitter P Base Bipolar Technology 2.2 En 20 Cross Section passivation field oxide Actually Technological We The have shades right transistor silicon already structure ofprocesses structure blue is named not isrepresent atransparent, bit described some do different not the layers. make P-type therefore so from far itHere possible the is silicon created itleft are is possible to the while picture in aproduce names very the ofto complicated N-type the of squared study Q8 thesilicon transistor the next shapes vertical way, ones. is red. in profile. like structure dozens Inon reality, The theofjust right Q8 thein isactual cross sections.can picture. profiles relatively technological Functionally small Letbe us steps. visualized and remind itThe the is difficult, that squared following too, the although vertical if“sharp” not animation impossible, not scale shapes sois fivehitnot are colorfully. to represents times it by suitable On bigger the thethe grinding chain as than right, well. ofthe of there production On cross horizontal the is asection. left steps. picture, one.Thethere right is a more microphotography picture comes realistic fromface ofthe a of real biggest the structure actual transistor profile. profile on the visualized by selective etching. chip. emitter base collector metallization epitaxial layer Emitter Base Collector N P N insulation substrate buried layer buried layer interconnection Bipolar Technology 2.2 En 21 How it Originates? Thus how it originated? Here in few seconds. Actually it takes hundreds of hours and the real structure is even more complicated. The next slides provide a detailed walk-over trough a semiconductor chip manufacturing process. Keyboard P Bipolar Technology 2.2 En N 22 Buried Layer epitaxial layer The basic material is the P-type silicon wafer with the <100> orientation. On this substrate, the buried layer, the first part of an insulation and an epitaxial layer will be build up. Epitaxy Thermal Oxidation Names of the Layers Photolitography and Etching Ion Implantation first part of insulation Diffusion buried layer Epitaxy Oxide Etching Boron Annealing Ion Implantation (boron) Photo and Etching (insulation) Arsenic Annealing Ion Implantation (arsenic) Photo and Etching (buried layer) Oxidation Bipolar Technology 2.2 En 23 Collector Now, an interconnection of the buried layer and chip surface will be created. This is also the place for future contact to the collector. Names of the Layers Thermal Oxidation Photolitography and Etching Diffusion buried layer interconnection and collector contact Oxidation and Phosphorus Annealing Oxide Etching Diffusion (phosphorus) Photo and Etching (collector) Oxidation Bipolar Technology 2.2 En 24 Second Part of Insulation and the Base At this stage, the second part of insulation and the base layer will be created. Notice that the second part of insulation goes downward to the first part until join it. Names of the Layers Photolitography and Etching Diffusion Ion Implantation second part of insulation base Thermal Oxidation Oxidation Boron Annealing Ion Implantation (boron) Photo and Etching (base) Boron Annealing Vacuum Diffusion (boron) Photo and Etching (insulation) Bipolar Technology 2.2 En 25 Emitter The emitter layer will be created now. This operation is concurrently used for collector contact characteristics improvement. emitter Cross section Photolitography and Etching Names of the Layers Diffusion Thermal Oxidation diffusion for contact improvement Diffusion (phosphorus) and Oxidation Photo and Etching (emitter) Bipolar Technology 2.2 En 26 Contacts and Metallization The contacts to the particular chip components are created at this step. The components will be interconnected by metal strips - metallization. This is made of alluminium with the admixture of small amount of copper and silicon. Names of the Layers Photolitography and Etching Sputtering metallization Photo and Etching (metallization) AlCuSi Sputtering Photo and Etching (contacts 2) LPCVD Oxide Photo and Etching (contacts 1) Bipolar Technology 2.2 En 27 Passivation Finally, the last layer on the chip is created passivation. It is made of silicon nitride at the temperature of 400 °C and protects the chip from external contamination. In this layer, contact windows for the leads will be created consecutively. Photolitography and Etching Names of the Layers passivation Photo and Etching (passivation) Plasma Nitride Deposition Bipolar Technology 2.2 En 28 Final Wafer Treatment Silicon Wafer Chip 20 mm (structure) 525mm 340 mm VIDEO 320 x 240 During The silicon the manufacturing, wafer thicknessvarious is 525 micrometers. undesirable It is necessary layers occur because on the back of a mechanical surface. These strength layers during will theremoved be manufacturing by wafer - simply back side in order grinding not toand break thethe wafers. final thickness This thickness will be adapted is unnecessary to 340 micrometers. and even inappropriate On the video, for we the canfinalized see a working chip. cycle of a grinding machine. Bipolar Technology 2.2 En 29 Testing Onthe After If the the probe enclosed technological structure videoelectric process clip, there parameters is are finished, some fulfill electrical shots the parameters requirements, from a test site. of the functionality characteristicofcomponents each chip onare wafer measured is tested. Aon test probe equipment structures - tester made is connected for this reason to the on each chip by means silicon of wafer. metalThe pins probe and tests structures its electrical are measured onAseveral parameters. rejectedchosen chip iswafers colored. from each manufacturing lot. VIDEO 320 x 240 REJECT OK Probe structures Bipolar Technology 2.2 En 30 Assembly On the The Afterwards, silicon functional video wafer the clip, chips copper with there are chips base are soldered some iswith sawn bonded or shots up glued with from chip on aan aand diamond copper wires assembly isbase molded saw line. with into into leads. individual a molding Thechips. leads compound are connected similarly with to thethe picture. chip contacts After theby final a thin treatment copper,and goldtests, or alluminium the integrated wirecircuit (0,1 mm). is completed. VIDEO 320 x 240 Bipolar Technology 2.2 En 31 1000 During Silicon For If But On The Now, the the the chips, source oxidation at there silicon dioxide, oxidation, right native higher itis for is diagram, wafer the speed is oxide prepared temperature oxide or also profile oxide more surface protects depends accelerated creation there grows familiarly in created the isis the absolutely the is the quickly on form oxidation silicon by access the by oxide, dependence aofthe temperature photolitographic in afrom clean, thin the is presence ofcontinues. aother place the layer very the ofwafer the by and of important growing reaction molecules With on the oxide dopant process where one kind growing film silicon hand (boron directly of onmaterial thickness of oxidizing silicon the and oxygen is the or right exposed on phosphorus) thickness ambient atoms for the on material. bottom tothe wafer oxidation the with and semiconductor oxygen of silicon picture. surface itoxygen The oxide intakes silicon. time. on higher atoms film, What away the or by Notice airborne It thermal itother technology. temperature and profile is isitsstill the 44% hand. willof It is oxidation. water oxidation more During is differences represented occur silicon. the not difficult faster after vapor the In only at the The oxidation the between room the occurs at afor place great SiO oxidation the oxidation. oxygen temperature already where layer material the bottom amount temperatures or ofgrows The oxide water this at(in astops. oxidation structure? picture, room the at already ofvapor asilicon form high At temperature. 1000 notice to ain exists, of temperature higher decreases get water quartz) °Cto the and the theA 2right for fusing by very temperature silicon then. vapor 1100 final oxidation various profile thin °C Resulting, isinterface 3-4 and oxide is the tools after slower times (800-1200 between Ofilm the and atoms oxidation. faster and (1-2 oxide the equipment the the with °C), nm) process than dry film amount silicon however, grows oxidation in is construction dry divided of or -of oxidation oxygen so by silicon the and called in reaction oxygen the oxidation because parts, isnative wayof 2 and butwater-saturated water oxide. molecules slowing that hydrogen in decreases itapproximately isvapor also down. accelerates are more with irreplaceable able slowly. silicon. oxygen. 44% to pass the Itofresults oxygen inits through athickness chip. into transport the thealready isprofile under to thethe createdon original silicon drawn interface. silicon oxide the following film surface up toand picture. the 56% silicon above interface it. by diffusion. O Si O water oxygen Si O 300 O Si O O Si O O O Si OOO Time [min] 600 O O Si O O O Si Si O Si Si O Si Si O Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Si Bipolar Technology 2.2 En 500 1000°C O O 1100°C 1000°C H O H O O O Thickness [nm] Thermal Oxidation SiO2 56% original surface 44% Si Oxidation Furnace Diffusion - the Principle 32 Oxidation (diffusion) Furnace During The After equipment thermal furnace process the the temperature process oxidation oxidation temperature starts forisoxidation with finished, oris as diffusion loading stabilized, well (400 or the as to diffusion the the wafers diffusion 1200°C) the wafers silicon process are processes require is, into wafers unloaded after the starts. asetup, are furnace. is high an out The placed temperature, oxidation controlled from gas They into system theare afurnace. quartz (diffusion) therefore automatically or inserted develops In some siliconslowly processes carbide an the furnace. appropriate quartz accurate notcarrier to the The tube deform to temperature process -ambient is ±1°C a placed boat. the orproceeds wafers for Several better. into isthe lowered aby heated heating boats in fast a before quartz heating. are wafers element. putit. orinside on In silicon To the most reach the loader carbide cases, tube. arm. the tube. appropriate In wafers theOn furnace, are the loaded temperature backside there into can of thestability the betube up tube, to atlengthways, several lower there temperature ishundreds a thin thegas heating silicon and inlet element the tube wafers process connected consists at the to a gas of same temperature three time. system. zones. ramps-up The Each gases zone after blowing has thean insertion. from individual the front power aresupply exhausted and control. to a The sanitation device. temperature is controlled by thermocouples (thin blue wires). gas inlet gas exhaust gas exhaust gas exhaust Bipolar Technology 2.2 En Oxidation Oxidation Furnace - Gas System Diffusion Diffusion Furnace - Gas System 33 Oxidation Furnace - Gas System Oxidation Oxidation Furnace Gas Flow Measurement O2 H2 H2O O2 combustion chamber flowmeters control valves N2 Bipolar Technology 2.2 En H2 O2 flowmeters valves N2 O2 quartz tube The gas task system of the gas for system the "wet" oxidation is oxidation to make in pure an is oxygen equipped or appropriate in with a mixture a combustion oxidative of oxygen chamber, environment and nitrogen inside inside which is simple. the hydrogen quartz tube. Itin There burns iscan oxygen justbe oxygen pure at the oxygen, orend oxygen ofaamixture and nozzle. an of appropriate Hydrogen oxygen and nitrogen proportion burns with of a nearly or nitrogen water-saturated invisible flowingblue through oxygen. flame. flow The The gas flow is measured controllers hydrogen combustion into theand tube. controlled produces water by mass vapor flowthat controllers. enters together On the withscheme the residual thereoxygen are rotameters the quartz for simplification. tube. 34 Diffusion On the Phosphorus Diffusion The phosphorus operation silicon is aatoms forms process wafer, temperature, the atoms structure gothere by through are which ismoved the represented the the the operation oxide diffusion by dopant the layer on diffusion time atoms mechanism with theand right the penetrate "windows" from picture. mechanism chemical environment N-type structure under ininplaces silicon islets the to ofsilicon where the (red) even environment oxide are ifthe wafer there formed on doped surface silicon is can no regions ininfluence diffusion P-type wafer in selected should and silicon the from in regions. be. places (blue) environment. depth The of innot wafer The thecovered regions diffused physical Ifprepared the structure by not layer effect oxide like protected and -this penetrate on diffusion dopant the is by placed picture oxide -surface into is into applied the is (green). kept silicon. here. at Let´soxide environment This The high concentration. temperature, ishave the on way a where look the The how silicon at the dopant the the islets phosphorus regions phosphorus wafer concentration formed surface doped by atoms diffusion must diffusion with decreases (can phosphorus be(chemical thick (or be ion also symbol in (N-type) enough implantation) downward compounds, P) (about are into from formed will the 500 e.g. the deepen P-type nm P surface under silicon more) are the - the become at silicon a so wafer. concentration high that surface. larger. temperature phosphorus This profile of 2Oor 5)and about atoms process is an additional 1000 doisnot also °C. penetrate process known as it. characteristics. "drive in". The boron diffusion proceeds in a similar way. Diffusion Furnace Diffusion - the Principle P P P P P P P P P P P P P P P P P P P P PP Dopant P P P P P P Ion Implantation P P P P P P P P P P P P P P P 1000°C Bipolar Technology 2.2 En 35 Diffusion Furnace - Gas System Onthe The In Oxygen Phosphine During the task case diffusion a enclosed oxidizes vacuum of PH of thediffusion can from video, the diffusion, also silicon planar from we furnace becan awafer asources, apowder phosphorus liquid see gas surface the source, system of a dopant sealing doped as source. nitrogen is well. silicon is to ofextricated create the That The bubbles is vacuum chemical is the an thesource from way 3 diffusion environment through how mechanisms planar of diffusion a dopant. silicon ceramics the ampoule. oxide liquid The saturated inside plates powder saturated and theitwith saturated quartz sweeps together with dopant tube phosphorus liquid with with atoms areavapor silicon similar dopant or along its oxide wafers tooxide compounds the into occurs is ones placed the sealed on with quartz inside the into -3valves the tube. wafer POCl between a quartz quartz surface. . ampoule silicon the tube. picture The wafers. The exhausted saturated itgas isThe POCl flowgas to oxide is the controlled system is, vacuum in supplies the bylevel end, oxychloride) regulator of the10quartz source Pa for(100 tube ofor 3On 3 (phosphorus electronic phosphorus with 000 000 nitrogen times flow diffusion. atoms orlower control nitrogen forthan Also meters. thewith the diffusion oxygen aatmospheric small flows into amount silicon. into pressure). the of oxygen quartz The tube optionally. whole of the diffusion furnace, ampoule is placedreacts into the with quartz POCltube ofhigh the diffusion temperature furnace and 3 at a phosphorus oxide occurs finally. then. Diffusion Furnace Gas Flow Measurement quartz tube doped silicon powder vacuum silicon wafers POCl3 seal N2 + POCl3 vapor Diffusion from Planar Source planar diffusion source Vacuum Diffusion flowmeters VIDEO 320 x 240 control valves N2 N2 Bipolar Technology 2.2 En O2 PH N23 O2 silicon wafers placed front side toward the diffusion source 36 Photolithography and Etching UV light source (dischange lamp) VIDEO 320 x 240 photolithographic mask projection system rinser developer negative photoresist oxide Oxidation Bipolar Technology 2.2 En Anisotropic and Isotropic Etching Subsequent Photolithography A The Immersing projection wafer is developer the system immersing covered whole removes andprojects wafer with etching the the awafer into light non-illuminated aispicture an the sensitive into etchant part aof of the technology matter photolithographic photoresist causes mixture -the of photoresist. sulfuric making etching from the mask acid possible ofwafer During uncovered and on and the hydrogen the to wafer form the covering oxide wafer the - itinisthe isa patterns fast pattern rinsed photoresist peroxide rotation - of this on will the windows the is of remove future the the silicon process wafer structure up the wafer toguarantees photoresist. the ofsurface. development. -silicon the wafer asurface On the is left uniform exposed -The enclosed wet picture, pattern etching. photoresist to video, UV there ofThe mask light. there ispolymerized the thickness details The are silicon illuminated particular is all copied wafer photoresist over phases with regions in thethe the is oxide wafer photoresist etching-resistant. of photoresist the layer. surface. photolithographic layer. polymerizeprocess. and they become insoluble by a developer. 37 Plasma Etching gas manifold Plasma In The plasma inserting described etching etching ofbatch is of theused equipment, nitride boat system for and utilizes the proceeded pumping the silicon high plasma reactivity nitride out several isofobtained films theofsilicon etching fluorine by and atoms a chamber wafers gas inhigh-frequency particular that at is the occurs followed same cases during time. by discharge for several For the photoresist decay thepreparatory atplasma the of removal. freon pressure etching, steps CF4Plasma ofalike about etching molecules 100 heating single Pa. wafer can up The at and be equipment equipment a very adapted final high cleaning is consists totemperature also be of close used. the of awafers. toThe quartz or anisotropic atadvantage an The vacuum electric nitride of etching, discharge chamber, etching single wafer itself therefore a- such vacuum system proceeds aitstate is pump is used the inoffreon more and gas for a very plasma isuniform high called precise frequency with plasma. etching. the patterns oxygen power etching.unit.During supply admixture. A gas flow the process, control unit thetakes gas composition care for accurate inside thepressure chamberand is changing a gas composition which can in bethe observed chamber. as a color change of the discharge from the orange through the blue up to a steel blue. Gas Flow Measurement Single Wafer System N2 O2 CF4 working chamber Anisotropic and Isotropic Etching 100 Pa gas exhaust cover high-frequency power supply Bipolar Technology 2.2 En loaded boat vacuum pump 38 Ion Implantation During Ion Phosphorus In Annealing the implantation places the of annealing, ions the where is implanted accelerated a the process the oxide diffusion wafer when by layer the atof the is aelectric the thick high dopant phosphorus temperature enough, field atoms andthe are atoms "shoot" under directed phosphorus activates proceeds tothe asthe ions well, phosphorus the wafer get silicon which stuck surface results wafer atoms in penetrate it surface. and in- they an they enlargement can into Let´s do participate not a have certain reach of a look depth the the in at the phosphorus under silicon. electrical implanted theconductivity. silicon regions. implantation surface TheThe result (gray) conductivity into is in represented the theP-type regions also depends, silicon on uncovered the wafer. structure of by oxide layer course, profile on onthe the (green). right amount bottom Theofdepth phosphorus picture. of penetration If a (dopant). sufficient depends dose This was on the speedcalled amount, implanted, (energy) the N-type dose, ofisislets ions an another and (red) it is occur important an important insidecharacteristic. the P-type implantation silicon on places characteristic. not protected Theby ions oxide speed layer. is in order of hundreds kilometers per second. Ion Implanter Dopant Diffusion P P P P P P 1000°C P P P Bipolar Technology 2.2 En P P P P P P P 39 Ion Implanter Onreach Ion Vapors Under Positively The For To the implanter example, process requested ions the enclosed ofpassing aphosphorus charged influence uniform proceeds is inphosphorus an the video, the ions equipment distribution voltage ofgap chloride ainget there hot high are off ions of filament is accelerated vacuum. used 100 the over (PCl aare line source kV the directed )inside are of the the whole ion brought and phosphorus by ion the to electric enter silicon theinto 3for implantation. a source the separator field ions wafer, implanters. source magnetic in speed the an ofof ions gap accelerator. beam is You ions. We field about by phosphorus can of have proper ofions 500 see anThere used ion is, kilometers the setting by chloride separator. loading the ismeans the of process the voltage per molecules ofofThe magnetic silicon second. aofdeflection magnetic of 50 wafers fall field. tointo phosphorus atoms field 200 system, into the thousand bends ormagazine, scanning atomic the implantation volts path clusters all abetween of over part ions with into of the so the the the surface. electric that vacuum accelerator silicon lighter charge wafer system ions- to ions. are and a describe more electrodes. control diffracted system. theThe principle than ion flow the of or the heavier beam implanter. ones. produced in this way hits the silicon wafer surface. VIDEO 320 x 240 accelerator vacuum Cl PCl heavy ions Cl 50 - 200 kilovolt + deflection system - P P magnet P P PCl P P Cl P P P P P P P P P 40 kilovolt - + light ions Cl ClCl ClPP Cl ClCl ions source P Cl Cl P Cl phosphorus chloride molecule silicon wafer PCl Cl phosphorus and chlorine positive ions phosphorus (P) PCl3 Ion Implantation Bipolar Technology 2.2 En P gap phosphorus doped silicon is N-type 40 Epitaxy Epitaxy The After If there process result theare issurface the ofany proceeds the growth phosphine process etching ofatthe is high is(PH finished, silicon from temperature molecules layer few thetoon silicon tens about the present, silicon 1200 3) a wafer °C. chloride the micrometers phosphorus Hydrogen surface. (SiClthick )The vapors atoms epitaxial layer past dope are has theintroduced. layer. the incandescent the growing same SiCl epitaxial silicon 4flows 4 reacts crystallographic wafers. with layer. On the present Boron enclosed When compounds hydrogen hydrogen properties video,atthere chloride can a as high be are thetemperature. used is the substrate, added, shots for doping itofbut starts The theitascan have aofloading reacting result well. wafers different with this reaction silicon on dopant a and susceptor areconcentration itfree etches silicon andthe their atoms wafer or unloading. even surface that different settle dopant. away. on You the can Itsilicon is also important see wafer thesurface tocontrol remove following board all the of its an contaminants crystal epitaxial lattice or surface defects of the silicon structure. structure. reactor. H H Cl Cl H H Cl Si Cl H H Cl H H Cl H P H H H Cl H H Cl Cl Si Cl Cl VIDEO 320 x 240 Si Si Si P Si Cl Cl Si Cl Cl H H Si H Cl Epitaxial Reactor Silicon - the Structure Dopant Bipolar Technology 2.2 En 41 Epitaxial Reactor Epitaxy Gas Flow Measurement N2 H2 HCl SiCl4 PH3 At this extremely Epitaxial During the reactor process, ishigh an the equipment temperature, chamber for with the the the process growth wafersofis the epitaxial flushed proceeds with in the nitrogen layer. way Silicon described and hydrogen. wafers onare theIn loaded slide the Epitaxy. on a graphite hydrogen The susceptor block environment -with susceptor. wafers the is susceptor The cooled susceptor down with is wafers then placed and is insidenitrogen warmed after a quartz up byflushing the glass induction bell-shaped it is taken heating out chamber. at from thethe Around the chamber,ofthere temperature chamber. about is 1200°C. an induction heating coil. B2H6 gas exhaust Bipolar Technology 2.2 En 42 Sputtering It is possible The Fast Against following argon the atoms target, toanimation sputter bombarding therealso represents is aother holder thematerials. target the withprinciple the areThe silicon obtained of by sputtering. an wafers. composition electric Thedischarge An sputtered ofargon the sputtered (Ar) inalluminium argon atom film between strikes isfrom theagainst the same the target target as anthe settles and an alluminium auxiliary on target the composition. wafers electrode plate (and surface at also Inathe low on insemiconductor pressure the a high other speed (0,1-1 parts(tens industry, of Pa). equipment) km/sec) The the target and films itofforms disperses isalluminium, connected a sputtered several to silver, thealluminium film negative gold, of alluminium. titanium, terminal atoms. nickel Magnetic Ifofthe aorhigh alloys field alluminium voltage of a magnet alluminium source plate placed with and - the copper the behind target auxiliary and the - issilicon target strongly electrode, are increases bombarded often anode, sputtered. theto by the argon atoms, positive efficiency one. of the The theprocess sputtered ionizedand argon alluminium it protects atoms are settle thedirected silicon on thewafers to the surrounding target. from the influence subjects. of the electric discharge. VIDEO 320 x 240 Al high voltage supply 1000 V Al Al Al Al Al Al Al Al Al Al Al Ar Al Al Al Al Al Al Al Al silicon Al Al wafers Al Al Al Al Al Al Al Al Al Al Al Al Al Al Argon Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al Al plate - target magnet pump Bipolar Technology 2.2 En Al anode 43 Contamination Boron, The smallest source danger phosphorus of ofchip contamination contamination structure or arsenic iscan is5are not µm be intentionally only width. airborne in The thedust, added to silicon.of diameter fragments impossibility Other ofhuman of various early elements, hair detection materials, is about suchwhich contaminated as 50 gold, µm. usually As copper we can or sodium see chemicals becomes on the can evident as microphotography, badly well during as influence a human testing thethe being silicon only hair or, - perspiration, properties, caught what isoneven the evensurface chip hair, worse, skin-particles inas anan imponderable can unreliable absolutely or make-up. product amount damage On by- this a the the customer. next ischip. called slide On the contamination. video, picture, there thereare isThe asunflower photo silicon of pollen contamination a silicon grains fragment caught is caused taken on thescanning by achip diffusion surface. electron of undesirable microscope. admixtures from impure surface or environment. VIDEO 320 x 240 196,9665 79 63,546 Au Cu 29 Gold 22,98977 Copper 11 Testing Bipolar Technology 2.2 En Na Sodium 44 Silicon Fragment Bipolar Technology 2.2 En 45 Clean Rooms 1 000 000 dust particles per cubic foot (approx. 30 l) Anfan In Therefore A The People standard imponderable air sufficiency forces working in the special environment, air clean of above inamount clean oxygen the rooms clean the rooms there of and filters, has rooms anaare 10 are admixture compensation the to built need about 10 air for 000 gets sufficiency 1can 000 dust of000 considerably airborne semiconductor through particles of the oxygen. air loss the particles in Wall one are filters influence devices provided cubic leakage in into one foot the the manufacturing. and cubic byaccording room silicon continuous the foot and technological properties. ofittoair isa These fresh exhausted (30 degree l). air are The of Details manufacturing the through filtration exhaustion induction rooms dimensions the and and with cause perforated itconditioning has of a raised semiconductor the controlled onloss the floor. perforated chip of (about After atemperature part are chips 20%). afloor comparable of temperature conditioned would and and abe dual to the size problematic ceiling and humidity. air. humidity provided of airborne inconditioning, such withparticles. an airenvironment. filters. the air is forced above the filters again. fresh air induction exhaust vent CEILING FILTERS flow rate 0,5 m/s temperature and humidity control over pressure 10-15 Pa 1 000 leakage perforated floor Bipolar Technology 2.2 En 46 Semiconductor Hygiene and Wafer Handling Semiconductor People air-conditioning working hygiene in the clean means with behavior air wear filtration special rules create for clothes an On Silicon It The is the not wafers wafers enclosed allowed areare must processed atvideo, be fragile alltogether thoroughly to there touch material, onrooms is athe cleaned the large silicon which handling scale, before influences wafer inprocess batches. with every the appropriate people made ofhandling working awafers material environment in the that does forfrom rooms the not release and for dust handling particles. with way one´s During high-temperature from of the hand. low temperature There unloading with operation. is them. aclean special operations, This vacuum asemiconductor is cleaning done there wand in are machine anused 25 wafers for up technology A hood, silicon a face wafers inside mask and the clean other rooms, clean room materials. but shoes it would are not the be the in equipment to athe handling. teflon placing or similar polypropylene The them wafer toon aand washing the isclean sucked oxidation cassettes. machine. by furnace means For Only high loader. of the the possible parts ofsimilarly the to maintain clothes. They the clean wear gloves without on their any hands. other wand, temperature washing powder processes, toisareplaced vacuum the wafers cleaner. byrooms sulfuric are Nevertheless, acid, fixed in various precautions. automatic quartz, hydrochloric graphite devices acid, orhydrogen are silicon always carbide peroxide preferred fixtures. and forammonium the handling. hydroxide. Then the wafers are properly rinsed in deionized water and dried in a spin-drier. Bipolar Technology 2.2 En VIDEO 320 x 240 47 Process Control Thevideo Perhaps On one technological silicon the clip,simplest there wafer, process isthere as a procedure well consists are ashundreds thefrom of most tens oxide to often of operations.measurement inspection thousands thickness is chips Achieving an inspection and thousands of up theof to specified dust a record silicon particles parameters of wafers the on are the in one operation silicon processed results wafer into every the before control is day. aand condition Therefore chart. after an forthe operation. starting operation the An subsequent operator results are check statistically operation. the wafer processed Therefore surface every in and a flow the operation of ends withlight. intensive operations an areinspection Even controlled a very orby asmall statistical measurement. particles methods cause- a visible by means lightofscattering. control charts This -inspection through computers. can be often seen on the enclosed video clips. Bipolar Technology 2.2 En VIDEO 320 x 240 48 Materials for the Semiconductor Technology The water semiconductor purity must technology be on therequires silicon purity extremely level,clean so this is environment the question of and units materials. to tens Water gramsisofone impurities of the most in thousand often used(million tons materialliters) during of the water. technological A similar purity process. mustHighly also be clean in water chemicals other is preparedlike byacids, the reverse solvents osmosis and photoresist. and the final cleaning processes in ion exchangers. It is called deionized water, or simply DI water. Contamination Photolitography and Etching Reverse Osmosis Bipolar Technology 2.2 En 49