3 ms·

Do they still have to deposit, mask and etch each of the layers?

by lainga 6y ago

wtallis 6y ago
3D NAND is successful and cost-effective because it's made by depositing dozens of layers at a time, then etching at the end of the process. Currently Samsung is in the lead by doing ~128L at a time. All their competitors reach 100+ layer counts by splitting the stack into two decks, eg. Micron's 176L NAND is 88+88.
- londons_explore 6y ago
  But they still have to do multiple steps per layer to attach the per-layer connections at the edge?
  - wtallis 6y ago
    Yeah, forming the staircase at the edge of the memory array is a big deal with a lot of steps, and it can take up a significant chunk of die area. But they can apparently do it with a very small number of photolithography masks: https://www.techinsights.com/webinar/memory-process-webinar-3d-nand-word-line-pad-wlp https://www.techinsights.com/webinar/memory-process-webinar-...
- cardiffspaceman 6y ago
  This search will give you a list of videos: 3d nand manufacturing steps It's a pretty clever arrangement, in this layman's opinion.
  - ohazi 6y ago
    https://www.youtube.com/watch?v=hglK1cf3meM https://www.youtube.com/watch?v=hglK1cf3meM https://www.youtube.com/watch?v=PdS3jkDKmOU https://www.youtube.com/watch?v=PdS3jkDKmOU
    - dkersten 6y ago
      That was very interesting! Could these techniques be applied to logic circuitry too or is there something preventing that?
      - xadhominemx 6y ago
        Logic circus don’t have the concept of word and bit lines - metal layers are much much more complex. And it’s inherently less economical to stack transistors because you would have to repeat many steps for every layer.
        dkersten 6y ago
        I get that the connection between each gate wouldn't be as uniform as in storage. I guess my question isn't can the exact technique be used, but rather the same principles/ideas. I guess its hard to etch all the different connections between gates if they're not uniform?

Do they still have to deposit, mask and etch each of the layers?

by lainga 6y ago

Do they still have to deposit, mask and etch each of the layers?

3D NAND is successful and cost-effective because it's made by depositing dozens of layers at a time, then etching at the end of the process. Currently Samsung is in the lead by doing ~128L at a time. All their competitors reach 100+ layer counts by splitting the stack into two decks, eg. Micron's 176L NAND is 88+88.

londons_explore 6y ago
But they still have to do multiple steps per layer to attach the per-layer connections at the edge?
- wtallis 6y ago
  Yeah, forming the staircase at the edge of the memory array is a big deal with a lot of steps, and it can take up a significant chunk of die area. But they can apparently do it with a very small number of photolithography masks: https://www.techinsights.com/webinar/memory-process-webinar-3d-nand-word-line-pad-wlp https://www.techinsights.com/webinar/memory-process-webinar-...
cardiffspaceman 6y ago
This search will give you a list of videos: 3d nand manufacturing steps It's a pretty clever arrangement, in this layman's opinion.
- ohazi 6y ago
  https://www.youtube.com/watch?v=hglK1cf3meM https://www.youtube.com/watch?v=hglK1cf3meM https://www.youtube.com/watch?v=PdS3jkDKmOU https://www.youtube.com/watch?v=PdS3jkDKmOU
  - dkersten 6y ago
    That was very interesting! Could these techniques be applied to logic circuitry too or is there something preventing that?
    - xadhominemx 6y ago
      Logic circus don’t have the concept of word and bit lines - metal layers are much much more complex. And it’s inherently less economical to stack transistors because you would have to repeat many steps for every layer.
      - dkersten 6y ago
        I get that the connection between each gate wouldn't be as uniform as in storage. I guess my question isn't can the exact technique be used, but rather the same principles/ideas. I guess its hard to etch all the different connections between gates if they're not uniform?