Why is 3d/v nand cheaper to make?

[johnl15278]

I've been looking into getting ssd and reading up to try and understand technology. I notice that same size Samsung 850 evo is cheaper than Samsung 840 evo.

My understanding of cost is that transistors used to make ssd historically got smaller and so company can stamp out more cells from same size wafer. This allow cost of ssd to get cheaper over time.

Yet with 850 evo the transistors are actually bigger than 840 evo. 40nm vs 19nm. Plus they also stack them 32 layers tall.

So doesn't the cost of material increase for v-nand?

 

[Valantar]

NAND becomes more expensive to produce as the litography gets smaller. Thus V-nand is cheaper, as it massively increases density at "large" litographies. High density (low material costs) with inexpensive (large litography) production techniques. It's a win-win situation.

 

[Acidicheartburn]

NAND becomes more expensive to produce as the litography gets smaller. Thus V-nand is cheaper, as it massively increases density at "large" litographies. High density (low material costs) with inexpensive (large litography) production techniques. It's a win-win situation.

Great explanation!

 

[hojnikb]

NAND becomes more expensive to produce as the litography gets smaller. Thus V-nand is cheaper, as it massively increases density at "large" litographies. High density (low material costs) with inexpensive (large litography) production techniques. It's a win-win situation.

Yeah, but because it increases density doesnt necesserly mean its cheaper to produce. 3D nand is much much more complex to make than 2D nand, as there are plenty of steps needed to be done for vertical cell arrangment.

Its all about the economics, demand and process maturity. A cheaper drive doesnt necesserly mean cheaper nand.