Micron steals a march on rivals with 176L 3D NAND shipments

Micron today revealed it has begun volume shipments of 176-layer 3D NAND, to set a new layer count benchmark.

The 176L tech means Micron has advanced over the competition and, all other things being equal, should be able to manufacture NAND at a lower cost per bit.

Update. Information about Micron using string-stacking added. 10 Nov 2020. Crucial use of 176L NAND in products info added 17 Nov.,

Micron is targeting the mobile storage, autonomous systems, in-vehicle infotainment, and client and data centre SSD markets with the tech. It should lead, Micron says, to ultra-fast edge computing, enhanced AI inferencing, and graphic-rich, real-time multiplayer gaming. The 176L die size is up to 30 per cent smaller than competitors’ 128L products, which means space-constrained products such as smartphones can dedicate less space for NAND.

Micron EVP for technology and products Scott DeBoer issued a canned quote: “Micron’s 176-layer NAND sets a new bar for the industry, with a layer count that is almost 40 per cent higher than our nearest competitor’s. … this technology sustains Micron’s industry cost leadership.”

The company is shipping dies to external and internal customers and expects external customer’s products using them to appear next year. Micron said: “Crucial is integrating Micron’s new 176L NAND in to some consumer SSD products now and over time as product lines are refreshed. The seamless integration model prevents inventory and part number logistical challenges for partners and customers.”

The dies use charge-trap technology and have a logic processing layer built underneath the layered NAND cells, to keep the overall die footprint small. That’s called a CMOS-under-array (CuA) architecture.

Micron CMOS-under-Array scheme.

Performance-wise, the 176L dies have a more than 35 per cent latency advantage over Micron’s 96L NAND and are over 25 per cent better than its 128L tech. Its maximum data transfer rate is 1,600 mega-transfers per second (MT/s) on the Open NAND Flash Interface (ONFI) bus, claimed to be industry-leading. The two things together mean system boot can be quicker and apps stored in NAND can launch faster.

Micron’s 96L and 128L NAND featured a maximum of 1,200 MT/s. The 176L product has 15 per cent faster mixed workload performance in mobile storage, compared to Micron’s equivalent 96L product.

The 176 layer number is 37.5 per cent more than any 128-layer NAND, and 22.22 per cent more than Intel’s 144-layer tech announced in May, and scheduled to ship in product by year-end. It is also a 57.1 per cent larger than Western Digital and Kioxia’s 112-layer product, again with an expected  product ship date by year-end.

Samsung, SK Hynix and YMTC  are all at the 128-layer count stage. Samsung expects to reach 176L by April next year, and will use a string-stacking method, combining two 88L dies.

Consultant Mark Webb of MKW Ventures tells us: “Micron does use string stacking for 176L. … Micron stack is also 88L I believe. String stacking is not two dies. It is one die/substrate [and]t has to do with how you break up the layers (think major stack and minor stack).

“A 176L logical die will probably have 190+ actual layers. There are additional layers in the process for select and for dummy layers.”

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