ΠΠ°ΠΊ Chinese news agencies, Yangtze Memory Technologies (YMTC) has prepared the second version of Xtacking proprietary technology to optimize the production of multi-layer 3D NAND flash memory. Xtacking technology, we recall, was presented at the annual Flash Memory Summit in August last year and even received an award in the category "The most innovative startup in the field of flash memory."
Of course, calling a multibillion-dollar enterprise a startup is clearly an underestimation of the company, but let's be honest, YMTC is not mass-producing yet. The company will switch to mass commercial deliveries of 3D NAND towards the end of this year when it launches production of 128 Gbit 64-layer memory, which, by the way, will be supported by the very innovative Xtacking technology.
As follows from recent posts, Yangtze Memory CTO Tang Jiang admitted at the GSA Memory+ forum the other day that Xtacking 2.0 technology will be introduced in August. Alas, the technical head of the company did not share the details of the new development, so we have to wait for August. As past practice shows, the company keeps the secret until the end and before the start of Flash Memory Summit 2019, we are unlikely to learn anything interesting about Xtacking 2.0.
As for the Xtacking technology itself, its goal was three points that a decisive influence on the production of 3D NAND and products based on it. These are the speed of the flash memory chip interface, the increase in recording density, and the speed of bringing new products to the market. Xtacking technology allows you to increase the exchange rate with a memory array in 3D NAND chips from 1β1,4 Gb / s (ONFi 4.1 and ToggleDDR interfaces) to 3 Gb / s. As the capacity of the chips grows, the requirements for the exchange rate will grow, and the Chinese hope to be the first to make a breakthrough in this direction.
There is another obstacle to increasing the recording density - the presence on the 3D NAND chip of not only a memory array, but also peripheral control and power circuits. These circuits take away from 20% to 30% of the usable area from memory arrays, and even 128% of the crystal surface will be taken away from 50-Gbps chips. In the case of Xtacking technology, the memory array is produced on its own chip, and the control circuits on another. The crystal is completely given over to the memory cells, and the control circuits at the final stage of chip assembly are attached to the memory crystal.
Separate production and subsequent assembly can also accelerate the development of custom memory chips and special products that are assembled in the right combination as if from cubes. This approach makes it possible to reduce the development of custom memory chips by at least 3 months out of the total development time of 12 to 18 months. More flexibility means more customer interest, which the young Chinese manufacturer needs like air.
Source: 3dnews.ru