[HN Gopher] Ultraprecise method of aligning 3D semiconductor chi...
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       Ultraprecise method of aligning 3D semiconductor chips invented
        
       Author : thebeardisred
       Score  : 111 points
       Date   : 2024-11-01 02:25 UTC (6 days ago)
        
 (HTM) web link (techxplore.com)
 (TXT) w3m dump (techxplore.com)
        
       | lawlessone wrote:
       | Could this also be used for manufacturing lots of other
       | microscopic things? layer by layer?
       | 
       | "Instead, their method finds errors up to 0.017 nm along side-to-
       | side measures (x and y axes) and 0.134 nm when assessing the
       | distance between the two chips (z-axis)."
       | 
       | Could you make some very very sensitive and tiny seismic sensors
       | with this?
       | 
       | edit: " Arbabi also points out that this method can be used to
       | make displacement sensors that can be used for measuring
       | displacements and other quantities. "Many physical quantities
       | that you want to detect can be translated to displacements, and
       | the only thing you need is a simple laser and a camera," he says.
       | 
       | For instance, "if you want a pressure sensor, you could measure
       | the movement of a membrane." Anything that involves movement--
       | vibration, heat, acceleration--can in theory be tracked by this
       | method.
       | 
       | "
        
         | g5pw wrote:
         | I made a home-brew seismic sensor using something similar, a
         | hard disk head arm assembly, a cd-rom laser (which has an
         | anisotropic lens and four photodiodes) and a Red Pitaya used as
         | PID, so I guess it can be done!
        
       | Etheryte wrote:
       | Maybe I'm missing something here, doesn't this simply move the
       | precision problem to a different part of manufacturing?
       | Previously you had to be precise with aligning the chips, now you
       | have to be precise with how you put those alignment marks on the
       | chips you want to align. Am I missing something here? Or is it
       | considerably easier to put the marks on the chips with sufficient
       | precision?
        
         | dooglius wrote:
         | I would think the alignment marks would be included in the
         | photomasks, so they would be part of the chips themselves
        
         | lambda wrote:
         | Putting marks on the chip with high precision is much easier;
         | that's done by the same kind of lithographic process that's
         | used for building up all the other layers of the chip, which is
         | generally via exposing a photosensitive layer of material with
         | light through a mask, and they already have ways of keeping
         | those mask layers in alignment.
         | 
         | But aligning multiple chips together is a different process,
         | and while it sounds like they previously had ways to do this
         | via simple optical inspection of those alignment marks, that's
         | less accurate than a holographic alignment using a laser.
        
       | iandanforth wrote:
       | The last bit about using this same technique for sensors is
       | pretty cool. Ultra-sensitive microphones or touch sensors would
       | be pretty awesome.
        
       | jrh3 wrote:
       | Nothing is invented, only discovered.
        
         | mhb wrote:
         | Maybe that's very clever or just dumb semantic nitpicking, but
         | unless you say more no one will know which you think it is.
        
         | perching_aix wrote:
         | > Nothing is invented, only discovered.
         | 
         | https://en.wikipedia.org/wiki/Invention
         | 
         | https://dictionary.cambridge.org/dictionary/english/inventio...
         | 
         | https://www.merriam-webster.com/dictionary/invention
         | 
         | https://www.britannica.com/technology/invention-technology
         | 
         | my opinion alarm is jumping off the desk over here, sheesh
        
         | nomel wrote:
         | That's a bit reductive. Without a human mind putting effort to
         | wander the concept space, that concept would never be touched,
         | and it would never be realized. The claim that all logical
         | things that can exist already exist since they're an
         | inescapable eventual logical conclusion seems a bit silly.
         | 
         | All that said, I do mostly agree.
        
       | heisenbit wrote:
       | Isn't this very similar to the way optical position encoders
       | work?
        
       | RachelF wrote:
       | This is not novel in general - the same technique has been used
       | in lens alignment for decades.
        
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