Clean Rooms (#3)
You guys sent me so much interesting e-mail on clean rooms that I'm doing one more post.First off, from Scott Hills:
Semiconductor fabs are some of the most insanely spotless places you'll ever visit. Leading edge production is at 45 nanometers -- 0.045 micron -- and heading fast to 32 nm. I had the privilege a year or two ago of touring a fab belonging to Micron, the largest U.S. memory chip maker, at their Boise headquarters.
I can't remember the clean rating, but judging from your other correspondent's details, I'm guessing it was at least a 100k: I had to put on the bunny suit, hairnet, goggles, mouth cover, gloves and booties. My notebook (paper one, not computer) was left behind, and they gave me a fab-safe notebook and pen, presumably made with special paper and ink that doesn't flake off any contraband particles. I spent about an hour touring the place, and it was supremely hot and uncomfortable. I don't think I could stand even one of the routine 10-hour shifts the staff pulls.
Someday I'll have to blog about my visit to the LIGO gravity-wave observatory in Hanford, Washington. They don't have a clean room, but because they are trying to detect the tiny perturbances in space thrown off by black hole collisions and stuff, they apply the clean room mentality to vibrations. I'll have to look up the details but their gear is so sensitive that trucks rumbling by miles away can be enough to mess up their readings.
Next, from JL:
I work at a little high-tech company that assembles magical crystals into optical devices. I work in a room that's 100K class for administrative purposes, though in reality the only clean air is in flowbenches (where it's needed). For larger and higher-end devices, we have a class 10000 and a class 100 cleanroom.
I've only been in them once - it was the first thing I did when I got hired. I got hired before Christmas vacation, and came in with the new year, and my first task was to suit up in the paper ninja suit and help wipe down all the surfaces with really big alcohol wipes. You see, over Christmas the office cleaning crew had walked through the door marked CLEANROOM FACILITY, over the sticky mats, past the boxes of gloves and booties and the hanging paper suits, through the plastic strip curtains against the positive overpressure...
and mopped the place.
From Cibby Pulikkaseril:
Regarding your clean room posts: I used to work in a cleanroom, and we had to suit up to enter.
At first, it seemed fun - but that quickly faded.
The suit, the hairnet, the goggles, everything made me desperately uncomfortable. Couple that with the fact that you're basically doing menial labour, and it's not the waterpark fun you think it might be.
Also, we used to work with HF (hydrofluoric acid), which we were told, is the most dangerous acid to work with. It's not a strong acid, so you won't feel any burning if it contacts you, but the fluoro reacts with the calcium in your body, which can be fatal.
We had this calcium paste in the cleanroom, to use in case of emergency - Wikipedia says that the paste 'sequesters' the acid. The local hospital was also prepared for any HF-related accidents.
The lab manager loved to scare new employees, telling them that the HF would actually eat away at the calcium in your bones, filling our imaginations with images of finding bodies, in ripped cleansuits, with limbs ending in ash and dust.
Years later, I was working on a research project and I needed some HF etching done. We went to the physics department at a university and got a Ph.D. student to help us. No cleansuit, no goggles, shorts and sandals. He handled the acid then rubbed his face, and I imagined him melting into a boneless sac of liquid, like the Ray Bradbury short story.
Cibby e-mailed me the next day and added this evocative and beautiful bit of description:
With all these comments about cleanrooms and the odd, sterile environment, I feel it's prudent to mention one of the most wonderful aspects of microfabrication... when you build these tiny devices, it's an incredibly beautiful world.
For one project, we built these devices that were no more than 10 microns by 10 microns. At this level, colours take on an otherworldly intensity: blues are the purest blue, gold is shimmering like no gold bar you've seen, and even the translucent photoresist appears jellylike and alien.
The devices were laid on this little hills, called mesas, that were, under the microscope, like a world of repeating Mayan temples. You'd almost want to shrink yourself down to visit these places.
For another project I made these devices on a crystal by poling the crystal. To the naked eye, you wouldn't see anything, and even under the microscope, there'd be nothing to see. With a twist of a polarizing filter, though, the blue light would shine through the device, illuminating it in these soothing hues of blue, erupting like a secret message, lost after 1000 years.
It's a beautiful world down there....
That is a remarkable piece of writing.
Of course, I have to follow up that sublime post with a story about peeing. From DQ Fitness Advisor Doug Walsh:
A friend of mine used to supervise a clean room at a major pharmaceutical company -- I won't say which one.
He came in one day and caught one of his coworkers urinating in the corner of the clean room. Needless to say, the man in question was unemployed by the end of the day.
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