Stuffing the wafers: SanDisk presses on with 48-layer 3D NAND chip

32 layers is so yesterday, man. SanDisk has a 48-layer 3D NAND chip in pilot production. Yeah, you heard me, the big four-eight. This can be seen as catch-up work as Samsung is now shipping its second generation 3D V-NAND chip, with 3-bits/cell and Dell using these 128Gbit dies in the SC-Series of storage arrays to offer …

[Chris Evans]

SD or SSD

Are the chips going to be suitable for SD cards or SSD drives or both?

Presumably the SD interface/controller is now the bottle neck?

[Charles 9]

Re: SD or SSD

In SD's case, probably the container. This is the main reason Micro SDXC seems maxed out at 200GB. Recall the SD cards are very thin (Micro SD even more so), so I don't think there's room for a 3D flash chip in them.

Hate to say it, but it may be time for a new SD spec to allow for fatter cards.

[Alan Brown]

Re: SD or SSD

"In SD's case, probably the container. "

Um, no.

The limit on microSD at the moment is the X*Y size of the die - that's why the largest shipping 2D one is 200GB

48 layers of SSD (the Z dimension) is still virtually nothing (a few tens of microns) compared to the thickness of the die substrate (a few hundred microns) and of the plastic encapsulation (a few thousand microns)

MiniSD and SD don't have these limitations at all.

As SD cards are usually made from reject SSD chips (the controllers map out the bad bits and access speed isn't nearly as critical), this probably means that >256GB microSD will be here shortly and dropping in price rapidly thereafter.

[Kevin McMurtrie]

Re: SD or SSD

I went back to the original PR and couldn't find any info on how they're stacking the storage. Other articles seem to indicate that this is 48 layers per chip. That sounds crazy, but I guess no more crazy than the current microSD process of grinding chips down to nearly nothing and stacking them.

[Stuart Halliday]

So does that mean they're 256Gb x 1 per layer? You've lost me.