(The following is an update of a post that originally ran on 6 December 2013. It was republished in 2024 as a part of a series on The Memory Guy blog to honor the 3D NAND inventors who have received the 2024 FMS Lifetime Achievement Award.)
A very unusual side effect of the move to 3D NAND was Continue reading “3D NAND’s Impact on the Equipment Market”
One of the most intriguing revelations during the Flash Memory Summit two weeks ago was Samsung’s new approach to stairstep etch in 3D NAND. This was one of numerous innovations the company’s EVP of Flash Products & Technologies, Kye Hyun (KH) Kyung, shared during Samsung’s Tuesday Morning keynote presentation.
The Memory Guy would point readers to the pdf of Samsung’s presentation on the Flash Memory Summit website, but it isn’t there, and it’s unlikely to ever be posted there. Samsung seems to have a policy that prohibits sharing such presentations.
Although I was unable to get a copy of the drawing that the keynoter used, I have tried to re-create it using, of all things, Excel! The result is the graphic for this blog post. The only thing I was unable to easily recreate was the different colors representing the layers of the 3D NAND. You’ll need to use your imagination and envision layers of two colors, with all the surfaces exposed on the top being the same color, but at different layers of a 64-layer structure.
Today’s common approach to 3D NAND’s stairstep is to etch a simple step pattern in one dimension, which I illustrated in an early 3D NAND blog post four years ago. This is a challenging Continue reading “How Samsung Will Improve 3D NAND Costs”
From time to time I get questions from investors in the memory business asking: “What is a multilayer cell?”
The answer is: “There is no such thing: It’s a misstatement.”
The term “MLC” has, by a number of people, been mistranslated to “multi-layer cell.” The misunderstanding appears to have originated in the financial community. People in the flash memory business never use the term at all.
Yes, we talk about MLC, but to us the term means “multilevel cell”.
A multilevel cell is a cell that uses varying voltage levels to represent different states. With four voltage levels the resulting four states on a single cell can be turned into Continue reading “What is a “Multilayer Cell”?”
