[HN Gopher] Ultraprecise method of aligning 3D semiconductor chi...
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Ultraprecise method of aligning 3D semiconductor chips invented
Author : thebeardisred
Score : 163 points
Date : 2024-11-01 02:25 UTC (7 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!
| pfdietz wrote:
| Oh man, this is giving me The Amateur Scientist vibes. What
| would C. L. Stong be doing with today's technology?
| 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.
| sandworm101 wrote:
| Ultrasensitive microphones are easy and have existed for
| decades. From a shotgun mic at a rock concert to a laser
| interferometer detecting gravity waves, the problem is the
| same. The issue is not detecting vibration but shedding off
| those sounds you dont want to hear. This new device will
| certainly be able to detect vibrations, but is likely useless
| outside of ultraquiet environments.
| 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.
| jrh3 wrote:
| I think only discovered. It was always there, but someone(s)
| just had to do the work to find it.
| mitthrowaway2 wrote:
| There's a word for this concept, discovering useful
| techniques that were always there but which nobody else had
| discovered before; we call it "invention".
| 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
| jrh3 wrote:
| It's a great mental exercise. Reading it, my opinion alarm
| went off. (Thank you for the source material!)
| 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.
| magicalhippo wrote:
| I like to think of it more like a scale. Some things are closer
| to being invented, other things are closer to being discovered.
|
| I'd say we've discovered pi, and the fractional quantum Hall
| effect[1]. And I'd say we've invented low-density parity-check
| codes[2] and single-photon avalanche diodes[3].
|
| [1]:
| https://en.wikipedia.org/wiki/Fractional_quantum_Hall_effect
|
| [2]: https://en.wikipedia.org/wiki/Low-density_parity-
| check_code
|
| [3]: https://en.wikipedia.org/wiki/Single-
| photon_avalanche_diode
| random3 wrote:
| Go back to the source (book, whatever) and read it again, it's
| unlikely that it said that nothing is invented and you missed
| the point. E.g. electromagnetism was discovered - electric
| engine was invented(mayb as a result of the discovery, maybe
| not). You can discover how a wheel works or invent a wheel
| without discovering the principle.
| pfdietz wrote:
| I mean, one could say no one ever writes a book, they just
| discover it, since that sequence of characters (like all other
| sequences) was already implicit in reality.
|
| I think this points up the problem with what you're claiming.
| There is sufficient creativity to get to the exact sequence of
| characters (or exact configuration of elements for the
| invention) to distinguish invention (a kind of creation) from
| mere discovery.
|
| In mathematics, though, we say a mathematician discovers a
| proof, even if the proof is very creative. So maybe it's not as
| clear as all that.
|
| Maybe the problem is the nature of constraints around the
| innovation? If it's sufficiently constrained there's little
| room for creativity, and the word discovery is more
| appropriate, even if it was hard to find.
| heisenbit wrote:
| Isn't this very similar to the way optical position encoders
| work?
| scheme271 wrote:
| I think the difference is that you don't need to change the
| focus of the optical sensors in order to verify alignment. So
| you don't have to worry about movement while the focus is
| changed.
| RachelF wrote:
| This is not novel in general - the same technique has been used
| in lens alignment for decades.
| kabouseng wrote:
| You also need to take into account your manufacturing precision
| you can achieve with fabricating the lenses, how accurately you
| can position the lenses relative to the work piece etc. From my
| cursory reading of the paper it assumes perfect lenses and
| positioning, and only simulates the alignment procedure. Still, a
| worthy paper, but as others have mentioned, not much different
| than the methods used for optics alignment.
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