News Micron debunks Fab 2 nitrogen leak rumours

Discussion in 'Article Discussion' started by bit-tech, 6 Jul 2017.

  1. bit-tech

    bit-tech Supreme Overlord Staff Administrator

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  2. jb0

    jb0 Member

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    Now I'm curious. Because a nitrogen leak is one of the LEAST eventful things that can happen in a fab. It is non-toxic, non-corrosive, non-flammable, non-explosive, non-reactive, and already some 80% of the surrounding air anyways. Pretty much anything else is MORE noteworthy than a nitrogen leak.
     
  3. Wakka

    Wakka Yo, eat this, ya?

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    From what I've seen they've already said as much (no big deal and it's already up and running again)... But I wouldn't be surprised if suddenly one of the big memory manufactures "takes one for the team", has a problem that causes supply shortage and every jacks up their prices because of "demand".
     
  4. Corky42

    Corky42 What did walle eat for breakfast?

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    The only thing that springs to mind is that as nitrogen is used like a cleaning agent a leak could have meant they had to pause fabrication until they secured a new supply to clean the equipment.

    Although as Micron have said they didn't have a nitrogen leak it's probably rather irrelevant. :)
     
    Last edited: 6 Jul 2017
  5. jb0

    jb0 Member

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    That's kind of my point.
    Given nitrogen is basically harmless and that so many other chemicals used in a fab are ... unpleasant, shall we say, anything NOT involving a nitrogen leak is inherently more interesting than the nitrogen leak they're denying.

    They've essentially said "Something went wrong in our fab, but it wasn't the single most boring thing that can go wrong in a fab".
    Rather than deflecting interest, it tends to draw it in.


    So either they are bad at lying and it WAS a major nitrogen leak(oh no, we are breathing slightly cleaner air than usual!), or something of actual CONSEQUENCE happened and they are being spoilsports by not saying what.
     
  6. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    The original report, linked in the article, clearly states that "the malfunctioning of the nitrogen gas dispensing system led to the contamination of wafers and equipment in the facility" - not that the nitrogen gas was a hazard to anyone, but that the dispensing system malfunctioned in such a way that wafers and equipment were contaminated.

    Even then, nitrogen may be inert but it's also not oxygen. Inert gas asphyxiation occurs when oxygen is displaced by an inert gas that would otherwise be harmless - and you pass out then die without ever feeling short of breath, because shortness of breath is based on excess CO₂ in the blood rather than a lack of O₂. Around eight people die in the US every year from nitrogen asphyxiation, according to the US Chemical Safety and Hazard Investigation Board, which is why warning signs are mandatory where pure-nitrogen atmospheres are in use.

     
    Last edited: 7 Jul 2017
  7. Wakka

    Wakka Yo, eat this, ya?

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    If nitrogen is so bloody efficient at killing humans, why is it not used more often?? Or... *conspiracy hat* Is that why "heart failure" is the most common cause of death for the past few decades? It's teh guv'ment knocking us off with an inert, untraceable weapon!!!11!
     
  8. Corky42

    Corky42 What did walle eat for breakfast?

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    Probably for the same reason water isn't used. ;)
     
  9. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    If you'd care to head over to the Wikipedia page I linked, you'd see that it is proposed for use in euthanasia and capital punishment specifically 'cos it's painless and quick. I quote:
    I watched that documentary when it first aired. Portillo sat inside a sealed chamber and completed a range of simple tasks like writing his name and putting square blocks through square holes. They then started to very slowly purge the oxygen with nitrogen and got him to repeat the tasks. (Naturally, safety personnel in SCBA were present with an oxygen mask for him so he wouldn't, y'know, die.) He very quickly started to screw the tasks up, but the really scary part was he was absolutely certain he was fine and had no idea what the problem was. Even when they were saying "okay, you need to put this mask on or you're going to die" he was waving them off, slurring "I'm fine, I'm fine."
     
    Last edited: 7 Jul 2017
  10. jb0

    jb0 Member

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    I was noticing the part where Micron denies there was an evacuation, and that was what really got me thinking.

    True, but it'd take a VERY large nitrogen leak to render a room full of breathable air hazardous. An oxygen leak can get very dangerous very quickly, by contrast.
    Next to everything else in the fab... poisons, carcinogens, mutagens, acids, and just plain firestarters abound. And not, like, a little poisonous. Like "actually deployed as a chemical weapon" poisons.
    Even the water is more hazardous than the nitrogen.

    Heck, the most likely thing to flood a room with enough nitrogen to choke someone is the fire control system, because a pure nitrogen atmosphere is almost certainly a better option than whatever was burning. Stops most fires, contains what it can't stop, and flushes any noxious gasses out into the air scrubbers. Sure you can't breathe without an air tank, but at least you won't ALSO get poisoned and acid-burned in addition to suffocated.
     
  11. Gareth Halfacree

    Gareth Halfacree WIIGII! Staff Administrator Super Moderator Moderator

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    Happens often enough to be a problem, especially in confined spaces and where (like in a semiconductor fab) nitrogen is being used as a purgative. Going back to the CSHIB report, there are a selection of case studies:

    So, of those: eight deaths were due to people using what was supposed to be air but was actually nitrogen (so not a leak), two due to using air that had too little oxygen (again, not a leak), two by not testing the atmosphere after it had been very deliberately filled with nitrogen (whoops), and one (the flare line worker) through what was effectively a nitrogen leak exacerbated by not wearing the respirator he was supposed to be wearing. In other words: it can, and most definitely does, happen, and because pure nitrogen is only ever-so-slightly lighter than air (heaver when it's cold, such as when it's just come out of a liquid nitrogen storage system) it doesn't quickly launch itself skywards like helium would.

    To reinforce the point, and at the risk of effectively having copy-and-pasted pretty much the entire report, here's CSHIB's recommendation on ventilation systems and nitrogen leak risks:
    (My emphasis.)
    Got any figures to back that up? Remember that the nitrogen doesn't have to fill the room; it only has to displace enough oxygen to bring the concentration down to around the 5 percent mark and you're in a coma within 40 seconds.

    EDIT: Here's a report on a nitrogen leak in an LG Display factory that killed two and injured four in 2015. Three construction workers died of nitrogen suffocation at an SK Hynix plant that same year. So, I don't think there's any question that a nitrogen leak in an electronics facility has the potential to be lethal, is there?
     
    Last edited: 8 Jul 2017
  12. edzieba

    edzieba Virtual Realist

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    Even outside the main wafer lines (that are pressurised by the Nitrogen to reject contaminants) fabs are high-class clean rooms, so are powerfully and continuously ventilated in order to keep the atmosphere scrubbed. A simple leak from the low-pressure line systems is not going to be sufficient to drop the ppO2 low enough to be hazardous (hell, you could probably unzip the whole line containment and it would not have enough volume to do so, the pressure is only a little above ambient). You'd need large dumps from high pressure lines to cause a hazardous concentration before the ventilation could disperse it, and that's pretty hard to miss due to the loud howling sound that would accompany it.

    e.g. for wafer operations in a Class 10 or Class 1 cleanroom, the entire room volume is going to be circulated 360-600 times per hour, or an entire volume change every 6 to 10 seconds.
     
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