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Technology Hardware

From Silicon To Microprocessors 174

Posted by timothy from the step-by-sandy-step dept.
prostoalex writes "Jim Turley from Embedded Systems Programming magazine answers the question of where microprocessors come from. While the public generally knows about the silicon and microprocessor vendors, few can describe the process of turning the beach sand into the latest and greatest several-hundred-dollars-worth CPU."
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From Silicon To Microprocessors More

From Silicon To Microprocessors

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  • The birds and bees, flowers and trees (Score:5, Funny)

    by ObviousGuy ( 578567 ) <ObviousGuy@hotmail.com> on Wednesday February 04, 2004 @07:09PM (#8184431) Homepage Journal
    The microprocessor stork brings them.

    Right, mommy?

  • ...giant silver bolognas... (Score:5, Funny)

    by burgburgburg ( 574866 ) <splisken06@@@email...com> on Wednesday February 04, 2004 @07:11PM (#8184464)
    Raw silicon is grown into crystal ingots, which look like giant silver bolognas.

    That, my friends, is a really unpleasant image.

    Then it's sliced into exceptionally thin wafers about 6 to 8 inches (200 to 300mm) across, depending on the diameter of the ingot.

    Owwww!!!!

    • Re:...giant silver bolognas... (Score:5, Informative)

      by chullymonster ( 695441 ) on Wednesday February 04, 2004 @07:32PM (#8184713)
      Have a look at MEMC's website (www.memc.com), they produce silicon wafers like the ones in the article. The site has some nice pics and animations of their manufacturing process.
    • Mr. Weed: "I shall call you Eduardo!"
    • Raw silicon is grown into crystal ingots, which look like giant silver bolognas.

      That, my friends, is a really unpleasant image.
      I hesitate to imagine what they use for the casing...... Horta [70disco.com] intestines?

    • some neat stuff, despite you are not being serious (Score:5, Informative)

      by lingqi ( 577227 ) on Wednesday February 04, 2004 @10:27PM (#8186226) Journal
      * when cutting the ingots, people almost ALWAYS use a ring-blade; where the blade is on the inner edge of a ring larger than the ingot, and ingot is sliced. extra points for anyone who know why.**

      * ingots are not always "grown." (think dipping candles) there is also a technique where you start off with a polychrystaline ingot and use localized heating to progressively monocrystalize it by localized melting. The technique is similar to one of the methods of removing impurities from iron bars.

      * CMP is damn cool. I mean, it's nice and all hearing about "polish to within an atom" precision, but if you take a polished wafer, it would make the best mirror you'd ever own. Granted silicon is not the perfect reflective surface, but you won't get a mirror more accuratly shows every feature on your face. =) Otoh, when dusts and stuff DO get into the CMP machines, though, it scratches the wafer. Though you don't see it, when you trace failures on the wafer the failing gates would generally follow an arc shape (corresponding to the wafer and polishing head rotation), and from that you get the CMP machine checked out.

      random junk I thought that was kinda neat.

      ** I used to know about 3 years ago but then I forgot. so don't expect like a correct answer or nothing.
      • All the ingots I've ever seen (and I live right by the Motorola Museum, free admission WOOHOO!) were dipped like caramel apples. They end up looking pretty neat when completed. Like a wierd condom.

        I won't get any extra points for this becuase I'm having trouble imagining what you're saying, but if you mean the radius of the ring blade is greater than the diameter of the ingot, that's so it can slice the wafer in one clean cut.
        • hmm I thought my explanation is a bit inadequate.

          Imagine Xena's little tossing ring thing. Xena's tossing ring thing has the blade edge on the outer edge of the ring.

          reverse that, and put the blade on the INNER edge of the ring.

          make sure diameter of inner edge is larger than ingot diameter.

          put ingot through the center of the inner-blade ring cutter.

          proceed to cut.

          image here? ttp://www.atock.com/newproducts/

          The inner black area is the blade. stick what you want to cut through the hole and proceed to c
    • A prof at my University insisted in calling them "salamis" during my semiconductor materials course. And he had this English accent that made it hard to keep a straight face in his class, as he went on and on about his "salaaaaamis". R. I. Hornsey? You're damn right I am!

  • It's all about what catches the eye (Score:5, Funny)

    by Anonymous Coward on Wednesday February 04, 2004 @07:13PM (#8184493)
    or at least so I gather from the frequency with which the Silicone/Silicon mistake is made. Maybe if computer chips were warm instead of hot, and squeezably soft instead of hard, and bouncy always bouncy people would know more about them.

  • One supplier (Score:5, Informative)

    by ackthpt ( 218170 ) * on Wednesday February 04, 2004 @07:14PM (#8184507) Homepage Journal
    When I lived in Midland, MI (home to Dow and Dow Corning) 'silicon' wasn't uncommon in casual conversations, particularly in a city of 40,000 with a large engineering population. Dow Corning, besides silicone compounds also provides silicon to a local company literally in the sticks, Hemlock Semiconductor [hscpoly.com]. Some nice stuff on their site regarding products, 1 [hscpoly.com], 2 [hscpoly.com]

    I'd always thought these materials were made in hot, dry climates, like Arizona, yet there was a supplier right in my backyard.

  • Oh, everyone knows... (Score:3, Funny)

    by Faust7 ( 314817 ) on Wednesday February 04, 2004 @07:14PM (#8184518) Homepage
    Hellacious spawning vats in the dark dungeons of Intel, AMD, IBM, and Apple.

    *sqlorch*
    *SQLORCH* ...
    *Ding!*

  • Clean Rooms (Score:5, Informative)

    by nil5 ( 538942 ) on Wednesday February 04, 2004 @07:15PM (#8184528) Homepage
    The only thing I don't like about the process is the working conditions: annoyingly loud!
    For those of you that have never been in a clean room, there is a tremendous amount of ambient sound due to the very important air cleaning/circulation system. In order to make the clean room "clean", there can only be so much dust particles in the air. (e.g. 1ppm) (there are actually different classes of clean rooms)

    The ramification of this is that one can hardly hear one's voice. Personally, I'm glad I'm not in the semiconductor field :)

    • Re:Clean Rooms (Score:2, Interesting)

      by Pulse_Instance ( 698417 )
      I do work in a clean room, class 5 is our usual but sometimes a bit lower. I never hear the noise, it is actually nice and quited inside our Fab.

    • Re:Clean Rooms (Score:3, Funny)

      by ackthpt ( 218170 ) *
      For those of you that have never been in a clean room, there is a tremendous amount of ambient sound due to the very important air cleaning/circulation system.

      Well, shoot! That sure blows my image, I thought it was the disco music that people in Intel 'bunny suits' [tow.com] danced to.

    • Its not the laminar flow systems making the noise. (Score:5, Informative)

      by burnin1965 ( 535071 ) on Wednesday February 04, 2004 @09:15PM (#8185635) Homepage
      Unless you are talking about a clean room from the late 70s or the 80s, its more likely that the noise you are hearing is from the exhaust systems sucking fumes from processing equipment.

      The materials used to produce semiconductors are extremely deadly to humans as are many of the process by products.

      Pretty much every processing tool has multiple exhaust connections which remove potentially harmful fumes to a scrubbing system on the roof that removes the toxic chemicals which are then treated and disposed.

      There are other noises from the tools and support equipment but I assume you thought it was the laminar air flow filtering system because it sounded like high volume air movement. They do move high volumes of air but you don't want the air moving too fast as it will stir up any particles that may be present in the room.

      burnin

      oh, I do work in a clean room, have since 1989.

  • Geeks and history (Score:3, Insightful)

    by FreemanPatrickHenry ( 317847 ) on Wednesday February 04, 2004 @07:16PM (#8184535)
    A knowledge of history is almost always a Good Thing. I wonder how many programmers have never heard of Charles Babbage? ("Analytical Engine? What?") You should at least have a decent knowledge of the history of your craft. Call me old-fashioned, but my love of computer science isn't limited by EnterpriseJavaBeans and BiCapitalizedMumboJumbo and whatever buzzword happens to be out today. There's more to it than that.
    • The history of computer science is definitely covered in some of the lower-level courses, but I wonder how many are truly interested enough to remember...

      I don't know if knowing the history is necessarily important. It seems to me what is more lacking in computer science majors I've seen is developed mathematical and logical skill. But then, computer science is only my minor, so I might tend to think that all computer scientists should be mathematicians :P

  • Try Intel's museum (Score:5, Informative)

    by badzilla ( 50355 ) <ultrak3wlNO@SPAMgmail.com> on Wednesday February 04, 2004 @07:18PM (#8184560)
    If you can visit Santa Clara USA then Intel's museum [intel.com] has a nice introduction to the process of turning sand into chips.

  • I can, and in only 4 letters (Score:4, Funny)

    by Triumph The Insult C ( 586706 ) on Wednesday February 04, 2004 @07:19PM (#8184565) Homepage Journal
    V I S A

  • Man, I'm old! (Score:5, Interesting)

    by nordicfrost ( 118437 ) on Wednesday February 04, 2004 @07:22PM (#8184612)
    I read the article and find myself actually knowing in advance how silicon chips are made. You see, in the 80ies we had childrens books about computers that covered something more than how to start Word and update Winblows.
    • Heck, in the 70's I had to read the same computer books as the adults did! How they worked, how to program them, how to make your own digital circuits....

  • the truth (Score:5, Funny)

    by jjeffries ( 17675 ) on Wednesday February 04, 2004 @07:23PM (#8184616)
    a couple of macroprocessors get drunk, start messing around... they wake up the next morning full of regret... next thing you know, there's a new microprocessor for someone to install, dress up in a nice case, feed it RAM, and reboot it when it makes a mess, which will be all the damn time for the first few months...

  • tinker-toys (Score:5, Funny)

    by chunkwhite86 ( 593696 ) on Wednesday February 04, 2004 @07:27PM (#8184661)
    the latest and greatest several-hundred-dollars-worth CPU.

    Only if you're buying intel can you get the latest and greatest for only several-hundred-dollars-worth. We call the intel servers at work "tinker-toys" because they are wimpy and cannot get much real work done.

    The Alphaserver GS160, the IBM RS/6000, and the Sunfire 12k. Those are the manly servers that do the real work around here. I don't think you can replace fans in these things for "several-hundred-dollars-worth". ;-) The CPU's in these are a couple thousand dollars each.

  • Leaves out the meat... (Score:5, Interesting)

    by HermesHuang ( 606596 ) on Wednesday February 04, 2004 @07:30PM (#8184697)
    While informative on what it touches on, this doesn't describe what goes into making a chip. It describes how a chip is patterned. Then follows many many diffusion, oxidation, etch, and metallization steps that go between each photoresist mask step. I suppose it makes a good read for someone who wants just a general overview. But it makes it sound like making a chip is just a glorified film development process. I do microfab work, and the lithography steps are the steps we take for granted (mostly -- they still do take effort to get right, but are in general easier then what follows).

    • Re:Leaves out the meat... (Score:4, Informative)

      by stevesliva ( 648202 ) on Wednesday February 04, 2004 @07:52PM (#8184885) Journal
      I agree. Even given a perfect mask, you can still blow the chemistry (implants, trenches, diffusion, whatever) for a given process step pretty easily. It also doesn't seem to mention the chemical-mechanical polishing needed to smooth the wafers after certain steps-- that's easy to screw up also.

      But as far as an article targeted at a total layperson goes, it's okay. Not that most laypeople don't quickly lose interest when you start talking about wafers, masks, reticles, photoresist, process steps. You always have to start with the broader concepts and see when their eyes glaze over:

      What do you do?
      I work at a place that makes computer chips
      Oh really? What kinds?
      All kinds. I work in the ASICS group.
      ASICS? Like the sneakers?

      • What kind of qualifications does someone need to work at a chip fab? How did you get started? I find it fascinating..but, I have always been curious how people *got their start*.

        • Re:Leaves out the meat... (Score:5, Informative)

          by stevesliva ( 648202 ) on Wednesday February 04, 2004 @08:15PM (#8185082) Journal
          In and around the fab, there's a huge range of skills necessary, from babysitting machines to trying to figure out quantum mechanics.

          To work in a bunny suit on the production floor? A high school diploma is often enough. To work in test/yield improvement? An EE degree, perhaps. To actually develop the bleeding edge processes? A PhD in physics.

          There's far more to it than that, of course. And the actual chip designers could be across the parking lot or around the world.

          • A PhD in physics would help, however, I've watched people with and Bachelors and Masters degree ranging from business to chemistry to mechanical engineering all execute the job of process development.

            Of course these same people have been working in the industry for 20+ years and have more than earned a PhD with all the work they've done bringing the industry to where it is today.

            I just want to make sure you don't scare anyone away making them think they have to get a PhD in physics to get into the biz.

  • Misses one important point: yield. (Score:5, Informative)

    by Anonymous Coward on Wednesday February 04, 2004 @07:33PM (#8184717)
    Having smaller die sizes is not good just because you can put more dies on a wafer. It is because your yield will improve. Dust/contamination is the real enemey, and bigger dies have an (exponentially or even worse) higher risk of having one dust particle destroying the chip function. Cutting the size with 10% may well lower the production cost by 50%.

    And that is ofcourse why moving to a smaller technology (eg from .18 to .13) can be a real money saver (next to allowing higher clock rates).
    • Smaller dies can also mean a much cheaper package with less pins.
    • Also misses the huge amount of measurement and inspection needed to establish statistical process control of the physical and mechanical processes that the Etching Depositing and implanting equipment performs at each layer.

      Repeatability is the name of the game and you have to use all kinds of sophisticated measuring devices like Scanning Electron Microscopes, Laser particle scanners and electrical device measurements in the scribe lanes between the chips at each layer to keep the whole process running swee
    • In a semiconductor factory yield is a measure of the percentage of good die versus the total number of potential die on a wafer. It is not the measure of the total number of die produced from a wafer and is therefore not directly affected by the size of the die.

      You are correct that smaller die sizes produce more die per wafer, however, shrinking the structures in a die's circuit make it more susceptible to failure due to contamination. Therefore you are actually wrong when you state that a smaller die wil

  • Why just square chips? (Score:5, Interesting)

    by RobertB-DC ( 622190 ) * on Wednesday February 04, 2004 @07:33PM (#8184718) Homepage Journal
    From the article:
    For an example, let's look at a 200mm silicon wafer, which has about 986cm2 of surface area. That's about the size of a salad plate. Let's say your chips are square (most are) and they measure 10mm on a side?that's 100mm2 per chip. If the silicon wafer was also square you could fit 986 chips on your wafer. Alas, wafers are round so you can really only get about 279 chips on a wafer.

    I guess the obvious question, since using squares on a round wafer wastes a certain amount of silicon, is why squares? Why not build a hex grid? That would seem to maximize the usage of the available area.

    But then, I suppose cutting them out would be significantly more difficult.

    What about triangles, then? Straight lines up and down, and in one (or both) diagonal directions.

    On the other hand, someone's already thought of this:
    Intel's old i960MX microprocessor was octagonal. It was so big its corners had to be cut off.

    So my idea has an obvious flaw. The question is... what is it?

    • Re:Why just square chips? (Score:5, Funny)

      by Timbotronic ( 717458 ) on Wednesday February 04, 2004 @07:51PM (#8184869)
      I guess the obvious question, since using squares on a round wafer wastes a certain amount of silicon, is why squares? Why not build a hex grid?

      They tried this once, but all the geeks in the clean room started putting little orcs on the chips and played Dungeons and Dragons

    • Re:Why just square chips? (Score:2, Informative)

      by Anonymous Coward
      Easy, The octagonal intel chips was probably cut as a square. The corners were just wasted space. They were octagonal due to lithogrphy reasons, not to save space. Triangular chips are even worse then square in that regard. For the same area the crossection is larger making layout and lithography harder. Now triangles could still ork for small chips but if they are small you are not wasting much space anyway so its not practical to change your process to squease out an extra 1%.
    • A related question would be why not make the wafers square?
      • You could make them square but the manufacturing process to make the wafer pulls a crystal out of molten silicon and rotates slowly as it is pulled out. The resulting single crystal Boule is a cylinder, so you start with a round slice of silicon and would have to throw away a lot of it to create a square.

        The corners would also be a little fragile and the manufacturing equipment used to process the wafers would need to establish a plasma for example across the wafer all the way out to the corners - wasting

    • Shape of the Chip (Score:2, Interesting)

      by ackthpt ( 218170 ) *
      I guess the obvious question, since using squares on a round wafer wastes a certain amount of silicon, is why squares? Why not build a hex grid? That would seem to maximize the usage of the available area.

      But then, I suppose cutting them out would be significantly more difficult.

      What about triangles, then? Straight lines up and down, and in one (or both) diagonal directions.

      Well, NVidia discovered rotating them 45 degrees give them a diamond instead of a square. Think they're onto something?

    • Just a suggestion, but what would you do with the diagonal parts of the die (one die, not multiple die)? Most processors I have seen are not only square on the outside, they are also square on the inside. Correct me here if I am wrong though (/me checks his Pentium II processor on his key ring).

      So you either have a tremendously more complex internal design, which makes use of these diagonals or you throw away space on the die itself. And for what? Upgrading to a larger wafer and smaller dies would bring do
    • Square ( or rectangular) because the silicon crystal lattice wants to break along perpendicular directions and square because a diamond wheel doesnt change directions very easily. Any other shape would result in more broken chips and lower yield and higher prices.
    • Your ideas are good, thinking out of the box, and check this out for thinking out of the box, spherical semiconductor circuits.

      Ball Technologies [ballsemi.com]

      burnin
      • ...spherical semiconductor circuits. Ball Technologies [ballsemi.com]

        Heh heh... good one. And it got modded up as Informative instead of Funny -- I love it when that happens!

        Or maybe I just didn't poke around the ballsemi.com site enough to find the pictures of their 3-D wafer fab [gamespy.com]. :)
        • No there are not any pictures of a 3d fab on the website as this company is not a semiconductor manufacturer, they are a tool vendor that is working on a new concept. If you read the press releases you we learn a little about what they have acheived to date.

          Besides, I was merely pointing out that thinking up new ways of doing things is a good thing and there are others who are actively doing it. So considering that I posted a link to a company that is working on different methods of producing semiconducto
          • If you read the press releases you we learn a little about what they have acheived to date.

            Too cool! I thought you were pulling my leg, by finding a company named "Ball Semiconductor" and suggesting that they have something to do with spherical chips. That's why I thought it was more Funny than Informative.

            I guess it's a good thing Slashdot won't give me mod points anymore! :(
    • "I guess the obvious question, since using squares on a round wafer wastes a certain amount of silicon, is why squares? Why not build a hex grid? That would seem to maximize the usage of the available area."

      Chips are generally rectangular since they are composed of rectangualar sub-blocks. These sub-blocks are rectangular in part because transitors are laid out as retangles. Also, automatic routing tools route on a manhattan grid. Also, wire bonding tools only deal with rectangualr shapes. Flip chip bond p

    • Re:Why just square chips? (Score:2, Interesting)

      by torpor ( 458 )
      What about triangles, then? Straight lines up and down, and in one (or both) diagonal directions.

      Indeed, and in fact, this is one of the reasons why we need the International Space Station, because as it turns out, certain crystallization/sillication (whatever its called, apologies to the chemists...) processes, in a micro-gravity environment, are a lot easier to control in a fashion which produces high-yield, multi-dimensional composite core materials. At micro-nano-levels, gravity definitely takes its

  • The Silicon Fairy (Score:1, Funny)

    by Anonymous Coward
    You leave some silicon under your pillow and the next morning you will find the processor she leaves you. She is a little behind the times, still making Slot 1 types. Stupid bitch.

  • This doesn't make sense... (Score:5, Interesting)

    by James Lewis ( 641198 ) on Wednesday February 04, 2004 @07:43PM (#8184805)
    "Why not just use one big piece of film to expose the entire wafer at once? The problem is focus. As any photographer knows, the bigger the picture the blurrier the image. That's why big-screen TVs don't look so great up close. Chip images need to be ultra sharp, so a blurry "mega mask" wouldn't cut it."

    I thought big screen TVs were "blurry" up close because they had fewer pixels per area. Besides... in this case, you wouldn't be making the image bigger, you would just be making a LOT of tiny images at once. Can someone either explain how his explaination makes sense, or what the real reason is?

    • Re:This doesn't make sense... (Score:5, Informative)

      by stevesliva ( 648202 ) on Wednesday February 04, 2004 @08:02PM (#8184981) Journal
      I guess focus could certainly be a problem, but as far as wafer sized masks go, if you're creating a mask that costs many thousands of dollars, you're far less likely to have a defect in the mask if the mask is only the size needed for one die, and not the entire wafer. And since certain masks are not 1:1 masks but 2:1 or 4:1 masks, you'd might need a 1200mm mask for 4x a 300mm wafer. A 1.2 meter mask. See a problem?

    • Projection blur (Score:3, Informative)

      by Atario ( 673917 )
      I think he's talking about the fact that focus is consistent on a sphere, not a plane. Since the chips are flat, the image you project on them is only perfectly focused on a circle (the intersection of the perfect-focus sphere with the plane of the wafer). You can see this happen with regular slide-, TV-, or film-projection as well.

      It sounds like they focus the center exactly and let it get blurry the further out you go (this is the case where the plane is tangent to the sphere -- a zero-radius circle of
    • It doesn't make sense. For one thing, they don't even expose the entire mask at once - most machines do it in "stripes", after the original data was "fractured" (I work on the CATS fracture software). For another, it left out the problems involved in making the mask itself - one glitch, and you've got a $5000 perfectly flat glass paperweight. Making a mask to cover the whole area multiplies those problems.
  • "Embedded Systems Programming magazine"

    Isn't this a tad specific? Why not a magazine about processors period? Is that too big? Just how much content can you have being specific about Embedded Systems Programming. Seriously, I'm asking.

    And if it's about Programming, why is this an article about processors? I'm so lost, and i don't think it's my fault this time. Flame away boys i'm bored.

    • Re:ESP (Score:5, Insightful)

      by elflet ( 570757 ) * <elflet @ n e x t q uestion.net> on Wednesday February 04, 2004 @08:10PM (#8185050)
      Just how much content can you have being specific about Embedded Systems Programming

      A huge amount. Many embedded systems have real-time requirements, tight memory-space limitations, and a much lower tolerance for failure than desktop systems. If you're talking about a comsumer embedded device (e.g. a cellphone), you have to deal with power management as well. There are multiple operating systems to choose from, several types of processor architectures (including the Harvard Archirtecture typified by Intel's old 8051 family that has entirely separate memory spaces for instructions and data), and several buses specific to embedded systems work.

      Why should this matter? There are several embedded systems in your car, and I'm sure you'd be mightily ticked if your car just stopped working randomly. On a more mundane level, what about programmable thermostats or the security card readers where you go to work? That's not to mention the mission-critical embedded systems in aircraft and medical devices.

    • Just how much content can you have being specific about Embedded Systems Programming. Seriously, I'm asking.

      Well, having read ESP for at least 10 years, perhaps I can answer.

      A lot!! The amount of Desktop CPUs sold is a drop in the bucket compared to the number of embedded CPUs. Look around the average house and compare the number of "computer controlled" items versus the number of desktop (i.e, Windows, Linux, Mac) computers. Just in my living room alone I can think of the thermostat, X10 lighting contr

  • Wafer Diameter? (Score:5, Funny)

    by Betelgeuse on Ice ( 562714 ) on Wednesday February 04, 2004 @08:08PM (#8185029)
    Hmmm, and all this time I thought 200mm wafers were 8 inches and 300mm wafers were 12 inches. Maybe the author is a former NASA engineer...

    And I agree, clean rooms are no fun. Ever trying typing on a plastic-coated miniature keyboard with two pairs of gloves?

    • And I agree, clean rooms are no fun. Ever trying typing on a plastic-coated miniature keyboard with two pairs of gloves?

      That sounds awkward but you ever tried typing 2000+ lines of hex code on a ZX81? [u-net.com]

      Santa brought me one of those, a rubiks cube, a metal detector and the 1982 Guinness Book of World Records (Train spotter's edition I think) for christmas. I think my mum must have told him I was doing poorly in school or something. I do recall though, I specifically asked Santa, at his grotto in the loc

  • Too elementary... (Score:5, Informative)

    by sharkb8 ( 723587 ) on Wednesday February 04, 2004 @08:11PM (#8185059)
    They don't use beachsand, that's silicon dioxide (SiO2), also known as quartz.

    Pure silicon chunks are actually made from condensing a very pure Silicon gas called Silane. The chunks are broken up, and melted in a very hot furnace, with a crucible made out of quartz(usually). Any doping, or impurities to give the silicon it's different electrical properties are added at this point. Boron (B) is fairly common.

    Then, a nice perfect seed crystal of silicon is dipped into the molten silicon which starts to crystalize around the seed crystal. The growing crystal is turned and slowly pulled out of the liquid silicon as it grows to help keep it regular. The result is called a boule, or "the bologna looking thing"

    As a side note, the doping is usually too high at the top of the boule, and too low at the end of the boule, so only about the middle 25% is used.

    Then it gets sliced into wafers. etc. etc.

    • Re:Too elementary... (Score:1, Interesting)

      by Anonymous Coward
      Where do you think the very pure silane gas comes from? Magic?

  • Mistakes? (Score:5, Informative)

    by Anonymous Coward on Wednesday February 04, 2004 @08:12PM (#8185066)
    There are more than a few nits...

    (1) Silicon is not sand. Sand is silicon dioxide (well, most sand). It needs to be reduced (the oxygen needs to be removed) and purified. And purified. And purified. (I believe Brazilian quartz is actually the preferred stock for silicon dioxide, rather than sand, due to its purity.)

    (2) Photo-resist does not need to be electrically conductive. It does need to be capable of resisting attack by whatever chemicals are next in the step (especially the HF). Since they're usually polymers that are either polymerized or depolymerized by the exposure, they generally are not conductive.

    (3) Current generation laser steppers are not EUV. (They are UV, maybe DUV, being slightly less than 1/2 the wavelength of visible indigo.)

    (4) One could get the impression that each chip on the wafer is processed separately at each step.

    (5) Fabs and foundries are related but distinct entities. (I personally have worked in a fab, but never a foundry.)

    (6) It's the mask that is imprinted on the wafer's photoresist, not the chip.

    (7) Moore's law is incorrectly repeated. This is especially bad because it claims to be correcting the common belief (which it probably is). Moore's law was about the economics of chip density -- the most _cost effective_ density doubles every 18 months.

    (8) I've usually heard and talked about individual die and multiple dice. (And breaking up wafers into chips is called dicing.) Maybe others call them (plural) die, but not everyone.

    (9) The 200mm wafer area calculations are wrong. A 200mm wafer has a radius of 10cm; the area is therefore (10)^2*pi ~= 310cm^2. So one won't get 986 die from a square wafer and only 279 from a round one.

    (10) Lots and lots of companies don't build their chips on the smallest feature sizes possible. Very few can afford to manufacture 90nm chips at this point, so the bulk of chip _designs_ are manufactured at .13u, .18u, or larger.

    There are probably many more errors...

    RJ

    • Re:Mistakes? (Score:1, Interesting)

      by Anonymous Coward
      Regarding "mistake" #9: try fitting 310 1cm squares on a circle with area 310cm^2. You can't do it. It's a goddamn circle. I could believe 279 as cited in the article (too lazy to figure out the math).

      Most of your "errors" are missing details at best. This article provides an excellent introduction to the technologies, so quit being so pedantic.

  • I seem to recall.... (Score:1, Interesting)

    by Anonymous Coward
    While the article is a good introduction.. I think he omitted an important step in chip fab. IIRC, after you expose the photoresist and wash away the exposed sections, you need to pour a special acid which seeps into the channels of the photoresist and etches the patern into the silicon. Then you can remove the photoresist layer and move on.
    As he explained it he never mentions how the pattern get burned into the silicon. Tsk tsk.

    • correct (Score:2, Interesting)

      by burnin1965 ( 535071 )
      soon after the photo resist is developed it goes through an etch process which is usually a dip in a nice acid bath, or a shower in a nice acid spray, or my favorite, a plasma treatment in a vacuum chamber with RF or microwave and wonderful gases like Sulfur Hexafluoride, Hydrogen Bromide, Chlorine, Carbon Tetra-Fluoride, etc.

      But this may not always be the case. It may be headed for an implant step. A nice electron beam zaps the wafer while it is laced with boron, or arsenic, etc.

      burnin

  • Why the clean rooms? (Score:5, Insightful)

    by kindofblue ( 308225 ) on Wednesday February 04, 2004 @08:16PM (#8185094)
    More to the point, why are humans required at all in the manufacturing process. I would expect the entire manufacturing and testing process, from sand to plastic-encased chip, to be automated enough that people in bunny suits should not be needed. Maybe they are needed to replace the robots and fill up the supplies, but other than that, what do they do?
    • Satisfy the labor unions.

    • Re:Why the clean rooms? (Score:2, Informative)

      by Anonymous Coward
      You still need humans for a lot of the alignment-and-inspection work that the machines simply can't do themselves.

      Also, mostly the machines are made by different vendors, so they don't have communication protocols to "talk" to one another, or to talk to a central dispatching control system. Therefore you need operators to move parts from machine to machine, and to select the appropriate programs to run on each machine (the parts pass through each machine multiple times, getting different processing each t

      • I agree that humans are still needed for many inspections and troubleshooting, however, that's about where it ends.

        Manufacturers are able to completely automate the entire wafer handling process. The alignment for handling and processing is many times better than what any human could do.

        And there have been standard communication protocols for interconnecting tools and systems for many years now. The two most common protocols are SECS and GEM.

        burnin

  • Whose Power PC? (Score:2, Insightful)

    by marshall_j ( 643520 )

    "Where do microprocessors come from, Daddy?" That's an awkward question we all must answer at some stage in our careers. What mysterious process converts elemental silicon into elemental forces like Intel's Itanium or Motorola's PowerPC? Let us explore the wonder that is semiconductor creation.

    Shouldn't that include IBM? [macobserver.com]

  • the process of turning the beach sand into the latest and greatest
    I always wondered why people bragged about their new computer and made the comment about leaving mine in the dust!

  • recognizing people in bunny suits (Score:3, Interesting)

    by Anonymous Coward on Wednesday February 04, 2004 @08:53PM (#8185432)
    The article mentions that, with co-workers encased in bunny suits, you have to look at their eyes to tell people apart. When I worked in a fab, I noticed I became very attuned to people's body shapes and ways of moving. After working there for a while, I could subconsciously identify co-workers at the opposite end of a shopping mall, simply by the way they walked.

  • uhm... (Score:2, Interesting)

    by wisdom_brewing ( 557753 )
    "is basically purified beach sand" - since when is deoxidation considered purification? "about 6 to 8 inches (200 to 300mm)" - make that 8 - 12 inches... slightly sad that such trivial mistakes/oversimplicications are made in an otherwise good article...

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