Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
No, not that kind of baked.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.

user:
pass:
register,


                           

NexGen Clean Room

For manufacturing picoelectronics
  (+3)
(+3)
  [vote for,
against]

In the electronics manufacturing industry, one of the most important things is the necessity to control dust. One speck can ruin a complex processor chip, for example. So, great pains are taken to filter it out of the air, as workers move into and out of the clean-room manufacturing area.

In the future this technology needs to be improved, to keep pace with all the others. Here are my suggestions along those lines.

1. Paint EVERYTHING in the clean room with titanium dioxide, including the special suits people will wear.
2. Increase oxygen level in the work environment to 30% (20% is normal; back in the Carboniferous Era, Earth's atmosphere was as much as 35% oxygen).
3. Install lots and lots of ultraviolet lamps, to ensure that every painted surface is illuminated by UV.
4. Continue to use filters to catch the majority of dust.
5. Everyone needs to wear appropriate goggles to protect eyes from UV light.

What happens in this clean room is that the UV activates the titanium dioxide, such that any speck of dust that touches any painted surface will be destroyed. What the activated titanium dioxide does is catalyze a combustion reaction between oxygen in the air and whatever other substance is touching it, like dust. The enhanced oxygen level will increase the effectiveness of that reaction.

Since most dust is made of organic matter, rich in hydrogen and carbon, the result will be mostly water vapor and carbon dioxide, things that won't significantly affect the manufacturing processes (also see next paragraph).

Since most dust will be trapped by the ordinary filter system, only rather small quantities of dust will be "there" to be destroyed by this system. So, no huge fires and no significant air pollution from burned dust.

The manufacturing clean room will be super-clean, therefore.

Vernon, Jul 07 2012

[link]






       I don't know the details of modern semiconductor production, but don't some of the steps rely on UV- sensitive photoresists?
MaxwellBuchanan, Jul 07 2012
  

       So instead of fine dust that the filters can catch, you will have even finer ash.
MechE, Jul 07 2012
  

       Better hope there's not a fire. Even a 1% rise in atmospheric oxygen levels, such as may be caused by a leaky valve in a surgical theatre, can be a recipe for disaster. A 10% increase, and we're talking about people with fire in their lungs before automatic extinguishers can be triggered. I've dealt with oxygen explosions before, but never in an enclosed space. In the open air, your eyebrows are gone before you hear the bang. In a sealed room...
Alterother, Jul 07 2012
  

       //don't some of the steps rely on UV- sensitive photoresists?//   

       I believe so - but as the feature size shrinks, so too does the wavelength of light necessary to reproduce it on the wafer surface. Vernon is talking about future chip fabs, where we'll presumably be using X-rays, gamma rays, electron beams or such.
Wrongfellow, Jul 07 2012
  

       Fair point.   

       From where does the dust come? If it comes from people, and from air getting in past airlocks, then surely the solution is to have a people-free fab? Operate the whole thing as a sealed unit.   

       Better yet, operate in a vacuum. Dust in a vacuum must settle out almost instantly.   

       Even better yetter, design chips to cope with failure. This could be done by bolstering their egos and telling them it's OK. Alternatively, they could be designed in modular way, with enough redundancy that a one-time-only operation will bypass any failed modules and pull in spare ones. I'm sure this has been done or tried.
MaxwellBuchanan, Jul 07 2012
  

       The Soviets tried; they gave the job to Mikhail Kalashnikov, who came up with a motherboard that could withstand punishing heat and Arctic freezes, worked just fine when fully submerged in pig shit, was easy to clean and repair in the field, but couldn't run DOS to save its godless commie soul.
Alterother, Jul 07 2012
  

       //couldn't run DOS// So, a complete success, then?
MaxwellBuchanan, Jul 07 2012
  

       From the Soviets' standpoint, yes.
Alterother, Jul 07 2012
  

       [Wrongfellow] is correct; they are already using "deep ultraviolet" in today's fabs. The UV from the lamps needed to activate titanium dioxide may already be too-long in wavelength to affect current photoresists.   

       I'm not sure how much "ash" would remain after dust is combusted. Most ash is associated with minerals, and minerals make up a pretty small part of most organisms (not counting bones). I once read something about an experiment done in which someone carefully measured some soil, grew a tree in it over the course of several years, and then carefully removed the tree from the soil and measured it again. It had been diminished by something like two ounces. For a whole tree.
Vernon, Jul 08 2012
  

       If the uv /oxygen supply levels go out of control
rcarty, Jul 08 2012
  

       Ash from, say, a wood fire is almost always less than three percent. Other materials (hair, skin cells) are probably similar, and of course silicates (dirt, wafer particulate) wouldn't burn at all.   

       That being said, it's very friable, so even on the stuff that will burn you go from one largish (~50micron) particle to 10-20 1 micron particles. Still more than big enough to cause problems, and harder for the filters to stop.
MechE, Jul 08 2012
  

       No, didn't you read [MechE]'s annotation? //it's very friable,//
MaxwellBuchanan, Jul 08 2012
  

       // Dust in a vacuum must settle out almost instantly. //   

       Ahem. "Mean free path" ...   

       That being said, the vacuum idea is not without merit.   

       // X-rays, gamma rays, electron beams or such. //   

       MBE & EBE have been around for decades. The issue is more one of productivity.   

       Eventually your species will work out the method of making semiconductors that every other sophisticated spacefaring species uses, but until then, carry on. We're laughing with you, not at you. Honestly.
8th of 7, Jul 08 2012
  
      
[annotate]
  


 

back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle