azuser55 t1_ir3qa93 wrote
Reply to comment by paulerxx in Micron’s investing $100 billion to bring the country’s ‘largest semiconductor fabrication facility’ to New York by Avieshek
Too many vibrations in NYC to build a fab there
oandakid718 t1_ir4fyjo wrote
Is this actually a thing? Interesting
azuser55 t1_ir6ms5c wrote
Recently there was some work being done to upgrade a FAB. There is a neighboring fab across the street. To avoid disrupting their neighbors, the work had to be spec’d without heavy equipment, jackhammers, or large ground moving equipment. When you are dealing with nanometers of precision, even the smallest bump can ruin a batch of multi-million dollar wafers being run through lithography.
emelrad12 t1_ir7goka wrote
That seems like asking for trouble. Like what about cars?
DevilsTrigonometry t1_irb7v15 wrote
There's an orders-of-magnitude difference between the amplitudes of ground vibrations produced by cars and by jackhammers. Vibration isolation systems designed to handle normal traffic etc. would be overwhelmed by heavy construction equipment.
And when you say "asking for trouble," what do you see as the alternative? Space manufacturing isn't even close to being viable, so either we don't do nanometer-precise manufacturing at all, or we do it somewhere on Earth, and the latter means dealing with the possibility of ground vibration. (Or water motion, which is even harder to isolate.)
emelrad12 t1_irb9yy4 wrote
Isnt wind even worse?
DevilsTrigonometry t1_irbf072 wrote
It's much easier to isolate the contents of a low-rise building from wind than from the ground. The internal structure of the building can be made self-supporting, with the walls basically just 'floating' around it.
You can't really 'float' a floor over the ground - you have to transmit the force of gravity from the contents of the building to the ground, and any connection capable of transmitting force will also conduct vibration. There are all kinds of complicated engineering solutions for reducing the amount that's conducted, but they take up space and cost money, so it's usually more efficient to choose a 'quieter' site than to build a better isolation system.
emelrad12 t1_irbgxb9 wrote
Could they just use something similar to noise cancellation, like in headphones?
DevilsTrigonometry t1_irbkmal wrote
Active vibration cancellation is already in use in semiconductor fabs and other sensitive manufacturing applications. But it has technical limitations: just like active noise cancellation, it works better for lower frequencies, lower amplitudes, and smoother waveforms. So it's sort of the final layer of protection: first you choose a quiet site, then you construct the building and the equipment footings using passive solutions that dissipate as much vibration as possible and smooth out the jerks, and then you use active solutions on the equipment itself.
Adventurous_Ad4950 t1_ir6dupc wrote
It depends on where, the eastern part of Brooklyn has some small chip manufacturers sitting there (my friend works for a gov. contracted manufacturing facility there). I doubt a large scale operation like Micron’s would fit there without causing substantial community displacement though.
azuser55 t1_ir6lw2v wrote
I didn’t know that. Thank you for sharing your knowledge with me.
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