China's Yangtze Memory Technology Corp is readying its next-generation 3D NAND memory architecture — Xtacking 4.0 — despitesevere sanctions against the company, according to a document seen byTom's Hardware. The company has no plans to increase the number of layers with the two Xtacking 4.0 devices currently in development, but the family may get broader over time.
YMTC's Xtacking 4.0 lineup that the company has disclosed to some industry peers so far includes 128-layer X4-9060 3D TLC and 232-layer X4-9070 3D TLC NAND devices, which could eventually be used to build some ofthe best SSDs. The company plans to use string stacking for both. So technically, it will produce 3D NAND arrays with 64 and 116 active layers, which enables wafer fab equipment makers to keep supplying it with necessary tools without directly breaking U.S. export rules (so long as they obtain an export license from the U.S. Department of Commerce).
Swipe to scroll horizontally
| Generation | Model | Organization | Architecture | Active Layers | Total Layers | String Stacking | String Stacking (Total Layers) |
| G1 | X0-A030 | MLC | Conventional | 32 | 39 | - | - |
| G2 | X1-9050 | TLC | Xtacking 1.0 | 64 | 73 | - | - |
| G3 | X2-9060 | TLC | Xtacking 1.0 | 64 | 73 | - | - |
| G3 | X2-6070 | QLC | Xtacking 2.0 | 128 | 141 | 2x64L | L69+U72 |
| G4 | Test | - | Xtacking 3.0 | 192/196 | 196 | ? | ? |
| G4 | X3-9060 | TLC | Xtacking 3.0 | 128 | 141 | 2x64L | L69+U72 |
| G4 | X3-9070 | TLC | Xtacking 3.0 | 232 | 253 | 2x116L | L128+U125 |
| G4 | X3-6070 | QLC | Xtacking 3.0 | 128 | ? | 2x64L | ? |
| G5 | X4-9060 | TLC | Xtacking 4.0 | 128 | ? | 2x64L | ? |
| G5 | X4-9070 | TLC | Xtacking 4.0 | 232 | ? | 2x116L | ? |
It is unclear precisely what advantages YMTC's Xtacking 4.0 memory will bring, but typically Yangtze Memory has increased data transfer rates and storage density with every new node. Given that the company faces severe restrictions and cannot obtain all the tools it needs, Xtacking 4.0 could somehow address its limitations. Plausible advances would include increasing the number of planes to boost parallelism and bitline/wordline optimizations to improve latency. As with any semiconductor, a tighter-tuned variant could also offer improved yields.
YMTC has been producing its232-layer 3D TLC NAND memoryfeaturing its Xtacking 3.0 architecture in high volumes for over a year now and more recently expanded its Xtacking 3.0 family with 128-layer 3D TLC and232-layer 3D QLC offerings that are cheaper, easier to make and which comply with restrictions set by the U.S. government for China. The company's Xtacking 3.0 family of products uses string stacking coupled with hybrid bonding that employs an older process node for the CMOS portion of the chip (similar to CuA, but with a separate die).
Under the rules imposed by the U.S., Dutch, and Japanese governments, makers of wafer fab equipment should get an export license to sell equipment that can be used to make 3D NAND with 128 or more layers. Meanwhile, it looks like there is no formal limitation on stacking two or more wafers with less than 128 layers on top of each other.
Technically, string stacking is not a wafer bonding technique per se, but from a manufacturing point of view, building a 3D NAND array on top of another 3D NAND array on one wafer is similar to producing two 3D NAND arrays on two separate wafers. Therefore, makers of equipment could be using this asyet another loophole to supply wafer fab tools to Chinese entities.
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Anton Shilov
Contributing Writer
Anton Shilov is a contributing writer at Tom’s Hardware. Over the past couple of decades, he has covered everything from CPUs and GPUs to supercomputers and from modern process technologies and latest fab tools to high-tech industry trends.
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7 CommentsComment from the forums
A Saint Why can't the US sanction these Chinese companies for good?
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EyadSoftwareEngineer Because China is super power country with army of engineers and money, no one can sanction minds
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pug_s Sanctions will hurt US and Korean NAND manufacturers in the long run. You won't see these products today because they are selling it to other sanctioned companies like Huawei. Give it a few years and the Chinese will produce better and cheaper products than these countries putting them out of business.
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peachpuff EyadSoftwareEngineer said:
Because China is super power country with army of engineers and money, no one can sanction mindsDon't forget ip thieves
Reply
bit_user pug_s said:
Sanctions will hurt US and Korean NAND manufacturers in the long run. You won't see these products today because they are selling it to other sanctioned companies like Huawei. Give it a few years and the Chinese will produce better and cheaper products than these countries putting them out of business.They were on track to compete with US and Korean NAND-makers, anyhow. The sanctions are creating a speed bump, for them.
Before the NAND sanctions, Apple was already preparing to switch over to using Chinese NAND. In order to help make it a viable alternative, they had orchestrated technology-transfer by recruiting top engineers from US and Korean companies, to bring their expertise to Chinese NAND-makers. The sanctions put a stop to that, and kept Apple from switching suppliers as it had planned.
I really don't see how the sanctions are counterproductive, in the way that you claim. If your post is driven by facts, rather than emotion, please state your case.
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pug_s bit_user said:
They were on track to compete with US and Korean NAND-makers, anyhow. The sanctions are creating a speed bump, for them.Before the NAND sanctions, Apple was already preparing to switch over to using Chinese NAND. In order to help make it a viable alternative, they had orchestrated technology-transfer by recruiting top engineers from US and Korean companies, to bring their expertise to Chinese NAND-makers. The sanctions put a stop to that, and kept Apple from switching suppliers as it had planned.
I really don't see how the sanctions are counterproductive, in the way that you claim. If your post is driven by facts, rather than emotion, please state your case.
Even when the top engineers working in China left, the YTMC managed to created more advanced NAND and SMIC managed to develop an 7nm chip for Kirin 9000 chip for the Huawei phones.
CWk2lmdZSjwView: https://www.youtube.com/watch?v=CWk2lmdZSjw
The youtube video says all, Trump promoted fair competition by slapping sanctions for like to like to China. The more important thing is to promote IP protection betwen the countries. Biden on the other hand, promoted the CHIPS act which promoted US to invest in Fabs in US. The problem is that countries within the EU and Japan are doing the thing in the CHIPS act. Moreever, when you slap sanctions to these Chinese companies, they don't have to respect IP protection and in a few years, overcapacity will lead to falling prices and it is basically survival of the fittest. Considering that China's National Security policy to keep the semiconductor companies afloat, they will win in the end.
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bit_user pug_s said:
Biden on the other hand, promoted the CHIPS act which promoted US to invest in Fabs in US.CHIPS doesn't have anything to do with this. CHIPS is just about building US semiconductor manufacturing capacity before China invades Taiwan.
pug_s said:
Moreever, when you slap sanctions to these Chinese companies, they don't have to respect IP protectionThey weren't before. So, no change here.
pug_s said:
in a few years, overcapacity will lead to falling prices and it is basically survival of the fittest.I assume by "overcapacity", you're implying that China will sell chips below-cost? Such situations can be controlled via tariffs and even further CHIPS-like subsidies.
pug_s said:
Considering that China's National Security policy to keep the semiconductor companies afloat, they will win in the end.That's what CHIPS is.
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