by Rudy Rucker
An ultimate goal of dry nanotechnology is the creation of an "assembler," a fantastic little nanomachine that can turn out more
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nanomachines - including copies of itself (an onanistic process known as "self-replication"). You might set an assembler to work making assemblers for awhile, and then somehow signal the godzillion assemblers that now they should switch over to making, say, incredibly strong "club sandwiches" of alternating single-atom sheets of two kinds of metal. The "gray goo" problem crops up here. What if, like the brooms in the tale of the Sorcerer's Apprentice, the assemblers can't be turned off? What if they turn everything they can get their nasty little pincers on into more assemblers? The whole planet could end up as a glistering sludge of horny little can-openers. But the nanonauts assure us this won't happen; it is perhaps comforting that the main nanotechnology group is known as the Foresight Institute.
Wet nanotechnology proposes that instead of trying to build our own tiny machines, we use a "machine" that nature has already designed: the cellular reproduction apparatus of DNA, RNA, enzymes, and proteins. It's like finding a way to tell one of your DNA strands something like, "Oh, next time you copy yourself, could you whip up a few million copies of this particular tryptamine molecule for me as well?" It's all in how you say it, and Gerald Joyce and others at the Scripps Institute are making some slow progress in guiding the "machines" of biological reproduction. But there's still major obstacles in convincing DNA to do technological things like putting together copper yttrium sandwiches. "No, man, I wanna fuck!"
What it comes down to is that dry nanotechnology is about machines that we can design but can't yet build, and wet technology is about machines that we can build but can't yet design.
The field of nanotechnology was more or less invented by one man: Eric Drexler, who designed his own Ph.D. curriculum in nanotechnology while at MIT. Drexler's 1986 book Engines of Creation was something of a popular science best-seller. This year he published a second popular book, Unbounding the Future, and a highly technical work called Nanosystems: Molecular Machinery, Manufacturing, and Computation.
Drexler has the high forehead and the hunched shoulders of a Hollywood mad scientist, but his personality is quite mild and patient. A few years ago, many people were ready to write off nanotechnology as a playground for nuts and idle dreamers. It is thanks
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to Drexler's calm, nearly Vulcan, logicalness that the field continues to grow and evolve.
Our interview was taped at the First General Conference on Nanotechnology, which was held at the Palo Alto Holiday Inn in November, 1991. Despite the name, this wasn't really the first "First Nanotechnology Conference," as that one took place in 1989. But this was the first First Nanotechnology Conference open to the public, for fifty to a hundred dollars per day, and the public packed the lecture rooms to the rafters.
Rudy Rucker: Eric, what would be in your mind a benchmark, like something specific happening, where it started to look like nanotechnology was really taking off?
Eric Drexler: Well, if you'd asked me that in 1986 when Engines of Creation came out, I would have said that a couple of important benchmarks are the first successful design of a protein molecule from scratch - that happened in 1988 - and another one would be the precise placement of atoms by some mechanical means. We saw that coming out of Don Eigler's group. At present I would say that the next major milestone that I would expect is the ability to position reactive, organic molecules so that they can be used as building blocks to make some stable three-dimensional structure at room temperature.
RR: When people like to think of the fun dreams of things that could happen with nanotechnology, what are a couple of your favorite ones?
ED: I've mostly been thinking lately about efficient ways of transforming molecules into other molecules and making high density energy storage systems. But if you imagine the range of things that can be done in an era where you have a billion times as much computer power available, which would presumably include virtual reality applications, that's one large class of applications.
RR: I notice that you're talking on nanotechnology and space tomorrow. Can you give me a brief preview of your ideas there?
ED: The central problem in opening the space frontier has been transportation. How do you get into space economically, safely, routinely? And that's largely a question of what you can build. With high strength-to-weight ratio materials of the kind that can be made
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by molecular manufacturing, calculations indicate that you can make a four-passenger single-staged orbit vehicle with a lift-off weight that's about equivalent to a heavy station wagon, and where the dry weight of the vehicle is sixty kilograms.
RR: So you would be using nanotechnology to make the material of the thing so thin and strong?
ED: Diamond fiber composites. Also, much better solar electric propulsion systems.
RR: I've noticed people seem to approach nanotechnology with a lot of humor. It's almost like people are nervous. They can't decide if it's fantasy or if it's real. For you it's real - you think it's going to happen?
ED: It's hard for me to imagine a future in which it doesn't happen, because there are so many ways of doing the job and so many reasons to proceed, and so many countries and companies that have reason to try.
RR: Could you make some comments about the notorious gray goo question?
ED: In Engines of Creation I over-emphasized the problem of someone making a self-replicating machine that could run wild. That's a technical possibility and something we very much need to avoid, but I think it's one of the smaller problems overall, because there's very little incentive for someone to do it; it's difficult to do; and there are so many other ways in which the technology could be abused where there's a more obvious motive. For example, the use of molecular manufacturing to produce high performance weapon systems which could be more directly used to help with goals that we've seen people pursuing.
RR: I've heard people talk about injecting nanomachines into their blood and having it clean out their arteries. That's always struck me as the last thing I would do. Having worked in the computer business and seen the impossibility of ever completely debugging a program, I can't imagine shooting myself up with machines that had been designed by hackers on a deadline.
ED: In terms of the sequence of developments that one would expect to see I think it is one of the last things that you'd expect to see.
Appeared in Mondo 2000, Spring, 1992.
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Fab! Inside Chip Fabrication Plants
I fell in love with the Silicon Valley word "fab" the first time I heard it. This short, moderne word means "chip fabrication plant." A manager might, for instance, say "What kind of outs are we getting from the fab?" In the '50s and '60s, of course, fab was short for "fabulous," as in the detergent Fab, or as in the lines in ''Bob Dylan's 115th Dream" that go: "I ran right outside and I hopped inside a cab. I went out the other door; this Englishman said fab." Gear! Kicky!
After exceedingly many phone calls, I managed to get to go inside two fabs in Silicon Valley, one belonging to the chip-giant Intel, and the other to Intel's small challenger, AMD (Advanced Micro Devices). AMD recently won a court battle with Intel over the right to produce its own "K6" version of the popular 486 processor chips for DOS and Windows-based personal computers. AMD is very much a "we try harder" company, and they were the first to let me into their fab - a quarter-billion-dollar building in Sunnyvale called the Submicron Development Center.
A micron is a unit of measurement equal to one millionth of a meter. A typical human hair might be a hundred microns wide. The scale of chips is discussed in terms of the size of the smallest features of the patterns on the chip. Today's chips use features about half a micron in size, hence they are said to be using submicron designs.
AMD's Submicron Development Center was originally intended to be purely a research facility, but the demand for the AMD 486 chi
ps is such that the facility is now also being used for commercial production. It turns out to be crowded and a bit hellish in the AMD fab, which feels to be about the size of a wide office-building corridor plus maybe six offices on either side.
Something I hadn't initially realized is that being a fab worker is like being any other kind of assembly-line worker. It's a rigorous blue-collar job. Most of the workers are Asian or Hispanic. The AMD fab is open twenty-four hours a day, every day of the year
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except Christmas - and in the Intel fab they work on Christmas too. The workers pull twelve-hour shifts, with three shifts one week and four shifts the next, for an average of forty-one hours a week. Although some of the fab workers are highly paid engineers, starting pay for a simple technician is around $24,000 a year, which comes to something like $12 an hour.
What actually goes on in a fab? A fab buys blank silicon wafers and draws complicated patterns on them. This changes a wafer's value from $200 to $30,000 or more. It's almost like printing money. The catch is that each of the many machines used in a fab costs over a million dollars. And buying machines for your fab is kind of complicated, although the Sematech consortium is seeking to make this easier.
When a fab finishes a wafer, the wafer is shipped to another plant where the wafer is sawed up into chips and the chips are put into the familiar plastic cases with wires coming out. These secondary plants are mostly in southeast Asia - the Silicon Valley fabs are solely concerned with printing the chips onto the wafers. To avoid dust, the wafers are shipped in vacuum-sealed bags.
The essence of the environment inside a fab is that this is a place for chips and not for people. People are dirty. Their bodies flake and crumble, sending off showers of dust. One dust particle can ruin a chip, for instance by shorting out the separation between two nearby submicron circuit lines.
In the current prehistoric state of robotics, there is no hope of fully automating a fab, especially given the fact that the process technology is subject to being changed over and over. To deal with having dirty people in there, the fab must be maintained as a clean room.
The cleanliness of a room is specified in terms of the number of particles larger than one micron that can be found in a cubic foot of air. An average non-smoking restaurant might have a few hundred thousand of such particles per cubic foot. In a surgical operating theater, the level is brought down to about twenty thousand. In the outer hallways of a fab building, the level is ten thousand, while in the wafer-handling areas of the fab itself, the level is brought down to one individual particle per cubic foot. How? At AMD the procedure went like this.
My guide is Dan Holiga, a member of the AMD Corporate
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Rudy in the AMD gowning room.
(Photo by Dan Holiga.)
Training division, responsible for instructing new workers on clean room procedures and for arranging science courses for them at local colleges Dan leads me into the pregowning room. The floor inside the door is covered with sticky adhesive. I sit down on a bench and put some blue booties over my shoes so as not to track dirt into the locker room. The woman behind the counter can't find Dan's special fab badge, so she gives him a visitor badge like mine. We select building suits in our sizes: two-piece suits like tight-cuffed blue pajamas. The woman gives us each some white plastic shoes like bowling shoes.
In the pregowning room, we stash our street-clothes in the lockers and put on the blue building suits and the white plastic shoes. We wash our hands and put on hair nets and safety glasses. Dan has brought a camera with him. We walk through a corridor into the outer hallway of the fab building. This is the ten thousand particles-per-cubic-foot zone, and the air feels cleaner than any I've breathed
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in a long time. My allergies are gone; the odorless air flows smoothly into my lungs.
We pass a break room where some of the fab workers are having non-dusty snacks like apple juice and yogurt. Then we go into a second locker room. I'd thought we were already dressed for the fab, but that was just the start. The second locker room is the gowning room proper.
Here we put on latex gloves. Then we wipe off our safety glasses and our visitor badges and Dan's camera - wipe everything three times with lint-free alcohol-soaked cloths. We put on white hoods and "bunny suit" overalls made of Fibrotek, which is a sandwich of nylon and Teflon. We pull "fab booties" over our shoes and we put on face masks. We pull vinyl gloves over our latex gloves. This is starting to feel a teensy bit . . . obsessive. I'm reminded of the "environmentally ill" people you see in Berkeley natural food stores, shopping while wearing gas masks and elbow-length gloves. They'd love it here in the gowning room. But, I remind myself, this isn't about obsession here, this is about objective scientific fact: getting down to one micron-sized particle of dirt per cubic foot of air!
Now Dan leads me through the air shower: a corridor lined with air-nozzles blasting away. We hold up our hands and turn around, letting the air wash us all over. The invisible particles fall to the floor, where they are sucked away. In the air shower and in the fab, the floors are coarse grates, and the ceilings are filled with fans. There is a constant flow of air from above to below, with any showers of filthy human particles being sucked out through the floor grates. The air in a fab is completely changed ten times a minute.
I step out of the air shower and, fully purified, I step into the fab. As the Bible says, "I was glad when they said unto me, let us go into the house of the Lord." I am in the heart of the temple to the God-machine of Silicon Valley. The lights are yellow to avoid clouding the photo-resist emulsions; this gives the fab a strange, underworld feeling. The rushing air streams down past me from ceiling to floor. Other white-garbed figures move about down the corridor; all of us are dressed exactly the same.
On the sides of the corridor are metal racks holding boxes or "boats" of wafers waiting for the next stage of their processing. The
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racks have wires instead of shelves - there are in fact no flat horizontal surfaces at all in a fab, as such surfaces collect dust and interfere with the air flow.
The only hint of human contamination is the meaty smell of my breath, bounced back to me by the white fabric face mask I'm wearing. I wish I could tear off the mask and breathe the clean pure air of the chips. But then I would exhale, and the wafers wouldn't like that - detectors would notice the increased number of particles-per-cubic-foot, and lights would flash.
The layout of a fab is a single main corridor with bays on either side. To keep the bays clean and uncluttered, most of their machines are set so that the faces of the machines are flush to the bay walls, with the bodies of the machines sticking out into sealed-off corridors called chases. Like people, machines have bodies whose exigencies are not fully tidy. The chases are clean only to a ten particles per cubic foot level, as opposed to the bays and the main fab corridor, which are kept at the one particle-level.
As we move down the main corridor to start our tour, people recognize Dan and come over to pat him on the back or on the arm. Dan theorizes that in the clean room, people can't see each other's faces, so they tend to fill in non-verbal communication by touching each other. Another factor could be that, given that everyone is clean, there is no fear of getting yourself dirty through human contact. Or maybe it's just that you have less inhibitions towards someone who is dressed exactly like you. In any case, the fab workers seem to have a strong team spirit and sense of camaraderie. They're like happy termites in a colony.
The craft of getting a hundred 486 or Pentium chips onto a silicon wafer involves laying down about twenty layers of information. It's a little like printing a silk-screen reproduction with twenty different colors of ink. At each step a fresh layer of silicon dioxide is baked on, parts of the new layer are etched away, and metals or trace elements are added to the exposed areas.
