The 232-layer 3D flash memory chip is here: the single-chip capacity is 2TB, and the transmission speed is increased by 50%

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qubit | public account QbitAI

232 layer 3D flash memory chip is coming, the data transfer rate is increased by 50%, and the capacity can reach 2TB.

Micron is the first to launch the world's first 232-layer NAND recently, following the first launch of 176-layer 3D NAND last time.

△Tuyuan Micron Technology

Speaking of which, it is not the Micron family that competes with the number of NAND layers.

For example, Micron's old rival Samsung, the relevant research center also focuses on the number of layers: Samsung has previously announced the details of the eighth-generation V-NAND before the industry, the number of stack layersOver 200 floors.

So how much improvement can the chip performance be brought to by such a "high stack"?

Stacking layers is like building a building

The higher the number of layers, the greater the capacity NAND flash memory can have.

A simple analogy can be made like this:

In an overcrowded city where real estate is expensive and scaling out is costly, the only way to support the growing population is by adding floors, which areEquivalent to the NAND layer.

Similarly, the parking lot and some infrastructure are mainly located under the building to improve space efficiency, which is equivalent to the bottom CMOS layer.

Stacking NAND's bitcell arrays into more layers provides more storage bits per square millimeter of silicon, enabling higher densities and lowercost.

3D NAND transforms the solution idea from simply improving the process technology to stacking multiple layers, and successfully solves the problem that the performance of planar NAND is reduced while increasing the capacity, achieving capacity, speed, and energy efficiency.and improved reliability.

△Tuyuan Micron Technology

Micron's new technology doubles the bit density per unit area of ​​storage compared to competing chips such as Samsung, packing 14.6Gb per square millimeter.

Its 1TB chips are bundled in 2TB packages, each no larger than a centimeter on a side, and can store about two weeks' worth of 4K video.

In addition, Micron has made improvements to the bottom layer of the chip, the bottom CMOS layer consisting of logic and other circuits responsible for controlling read and write operations as quickly and efficiently as possibleData can be acquired both on and off the chip.

Micron optimized its data transfer path, reducing the capacitance of the chip's input and output, increasing the data transfer rate by 50% to 2.4Gb/s.

The contest of layers

Since NAND flash memory entered the 3D era, the number of stack layers has been getting higher and higher like a skyscraper, from the original 24/32 layers to the current 176 layers or even 232 layers.

The contest of the number of layers is the competition of the whole industry. Samsung, Micron, SK Hynix and other companies are all committed to the breakthrough of the number of layers.

Samsung is a leading company in NAND flash memory, and 3D NAND originated from Samsung.

In 2013, Samsung devised a method of stacking cells vertically, which concentrates cells on a single floor (similar to a high-rise apartment), which is also the world's first 3D cell structure"V-NAND", which can achieve 24-layer stacking in that year.

Since then, Samsung has continuously updated its technology and expanded its industrial line, and has launched 7 generations of products in 10 years to maintain its position in the NAND flash memory market.

In 2020, Samsung introduced the seventh-generation "V-NAND" with 176 layers, which uses "dual stack" technology, instead of etching all layers at once, it willThey are divided into two parts and then stacked on top of each other.

Therefore, the 7th generation V-NAND has a 35% reduction in cell volume compared to the 6th generation's 100 layers, and it canThe number of layers is increased to 176, while also reducing power consumption, increasing efficiency by 16%.

However, although Samsung first announced the details of the eighth-generation V-NAND, saying that its stack layer will exceed 200 layers, this time it is the first to mass-produce 200+ layers of flash memoryBut it is Meiguang.

It is worth mentioning that in the 232-layer 3D flash memory chip released by Micron this time, the stacking technology of NAND is not the first, but the same as the seventh generation of Samsung.Dual stack" technology.

That is, the 232 layers are divided into two parts of 116 layers each, and the stacking of these layers begins with a deep, narrow hole through alternating conductors and insulatorslayer etching.

The hole is then filled with material and machined to form the bit storage portion of the device.The ability to etch and fill holes through all these layers is a key limitation of this technology.

△ Legend: Tuyuan Micron Technology

At present, the third-generation QLC 3D NAND flash memory of the domestic chip company Yangtze Memory has achieved 128-layer stacking.

Netizens also have a very optimistic attitude towards the contest of layers:

Adding layers hardly introduces new problems.

Reference link:
[1] https://spectrum.ieee.org/micron-is-first-to-deliver-3d-flash-chips-with-more-than-200-layers
[2] https://news.ycombinator.com/item?id=32243862
[3] https://ee.ofweek.com/2021-12/ART-8320315-8110-30538953.html