3 ms·
I have basic understanding of a generic process. I mean specifically 200+ layers. Do they “just” deposit layer after layer after layer, 200-something times?
by murkt 4y ago
I have basic understanding of a generic process. I mean specifically 200+ layers. Do they “just” deposit layer after layer after layer, 200-something times?
- alyandon 4y agoI am not going to pretend to be a process engineer (I am chemical engineer by education) but I can't imagine any other way to do it than as you described. Would really love for someone more knowledgeable to chime in though.
- wtallis 4y agoThey deposit half the layers, etch holes through them and form vertical strings of memory cells, then repeat all that to build a second deck of layers on top. The interface between decks is a potential source of problems, but is more manageable than trying to drastically increase the aspect ratio of the holes that need to be etched through the stack. Etching through lots of layers at once is why 3D NAND flash memory is actually economical, compared to basically every other kind 3D chips where layers have to be built one at a time.