oandakid718 t1_ir4fyjo wrote on October 5, 2022 at 7:21 AM

Reply to comment by azuser55 in Micron’s investing $100 billion to bring the country’s ‘largest semiconductor fabrication facility’ to New York by Avieshek

Is this actually a thing? Interesting

azuser55 t1_ir6ms5c wrote on October 5, 2022 at 6:42 PM

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 on October 5, 2022 at 9:55 PM

That seems like asking for trouble. Like what about cars?

DevilsTrigonometry t1_irb7v15 wrote on October 6, 2022 at 6:14 PM

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 on October 6, 2022 at 6:28 PM

Isnt wind even worse?

DevilsTrigonometry t1_irbf072 wrote on October 6, 2022 at 7:03 PM

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 on October 6, 2022 at 7:16 PM

Could they just use something similar to noise cancellation, like in headphones?

DevilsTrigonometry t1_irbkmal wrote on October 6, 2022 at 7:42 PM

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.