The enthusiasm of 3D NAND stacking continues. How can Chinese companies catch up?

The 3D NAND stacking war is in full swing. If we say that several major international flash memory manufacturers, such as Samsung, Micron, Toshiba, Western Digital, and SK hynix, currently market their mainstream products with 64-layer (or 72-layer) 3D NAND, then Next year will be on the 96th floor. At the recent International Storage Seminar 2018 (IMW 2018), Applied Materials predicts that by 2020, 3D memory stacks can achieve 120 layers or even higher, reaching more than 140 layers in 2021. In addition to 3D stacking, storage vendors are also trying to increase unit storage capacity by improving data storage unit architecture and controller technology. Micron has recently introduced QLC 3D NAND, which has boosted unit storage capacity by 33%.

These conditions show that the international giants are accelerating the technological evolution of 3D NAND, so as to increase their technical barriers and widen the gap with competitors. Memory is one of the key chips for China’s development, and domestic companies such as Changjiang’s storage are also expected to By the end of this year, we will achieve low-volume production. When 3D NAND new product technologies enter the market, we will accelerate the pace of development. It is very important to keep pace with the evolution of international technology.

NAND flash memory 3D stacking will look 140 layers in the future? With several major international storage vendors rushing to promote 64-bit 3D NAND volume production in 2017, related products have started to enter the mainstream market this year. According to DRAMeXchange Data, the first quarter of this year's NAND flash brand factory revenue season decreased by 3%; second quarter PC solid-state drive (SSD) contract price price fell 3% to 11%. And the main reason for falling prices in two consecutive quarters, On the one hand, it is because the market is still in a state of oversupply. On the other hand, most SSD vendors are willing to lower prices in order to promote the latest generation of 64/72-layer 3D SSD products.

In this regard, DRAM eXchange research associate Chen Hao said that Intel, Samsung, Micron, Toshiba, SK Hynix and other manufacturers of the latest 64/72-tier 3D SSD have been sample testing to the main customers, but also has entered the mass production phase. This is the main reason that market competition will intensify this year.

In the context of falling NAND flash memory prices, the cost advantage has become the key to competition in the storage plant market. It is reported that Samsung began mass production of 64-layer 3D NAND, and the use of new Pyeongtaek plant to increase production; Micron to promote 64-layer 3D NAND is also very smooth; Toshiba, Western Digital started mass production of 64-layer 3D NAND since the second half of last year; SK hynix is ​​expected to increase the proportion of its 72-tier 3D NAND-enabled enterprise SSD shipments this year with the increase in 72-layer 3D NAND capacity and yield.

In addition to expanding the proportion of 64/72-layer 3D NAND production, storage plants are also advancing the development and mass production of next-generation technologies. It is said that Samsung will first mass-produce 96-layer 3D NAND and put 128-layer 3D NAND before the end of 2018. R&D. However, related parties also stated that because 96-layer 3D NAND technology is relatively difficult, Samsung or the 92-layer transition technology. Toshiba and Western Digital have previously announced that 96-layer 3D NAND has been completed R & D, and has repeatedly expanded investment in Fab6 factories. Amount to prepare for the mass production of 96-layer 3D NAND. Intel and Micron have stated that the development of the third-generation 3D NAND technology (96-layer) will be delivered by the end of 2018 or early 2019. Intel and Micron's 96-layer 3D NAND are expected. Mass production can be realized in the second half of 2019.

3D has become the main development direction of NAND flash memory technology. It means that the storage units are not in one plane, but stacked one on top of the other. In this way, the storage capacity of each chip can be significantly increased without having to Increase the chip area or reduce the unit, using 3D NAND can achieve greater structure and cell gap. This is conducive to increase product durability, reduce production costs. 3D stacking has become the main competition among NAND manufacturers.

QLC solid-state drives accelerated their entry into the market to improve data storage unit structure and controller technology to increase unit storage capacity and reduce production costs. This is another development direction of NAND flash memory.

On May 21st, Micron Technology took the lead in introducing the industry’s first solid-state drive that uses QLC four-bit cell storage technology and said that it has started to supply. According to the product data released by Micron, its new 5210 ION solid-state drive adopts 64 layers. The 3D QLC NAND and QLC architectures have a larger capacity than the TLC architecture, allowing a single chip capacity of up to 1Tb.

At present, the structure types of memory cells are divided into the following types: SLC, MLC, TLC, QLC. QLC four-bit cells (each cell stores 4 data), lower cost, larger capacity, but shorter lifetime (theory Rewritable 150 times, will enable companies to reduce production costs and gain high competitiveness. IDC research vice president Jeff Janukowicz said QLC Enterprise SATA SSDs provide an affordable way to migrate enterprise applications to flash memory , And have the opportunity to expand the potential market for enterprise flash memory.

In fact, not only Micron, but also Samsung, Toshiba, Western Digital and other companies are accelerating the development of QLC 3D DAND in order to reduce the cost of NAND flash memory production and improve product competitiveness. In July 2017, Toshiba and Western Digital announced the adoption of BiCS4 technology QLC flash memory, core capacity 768Gb. According to the introduction of Toshiba and Western Digital, 96-layer 3D NAND using BiCS4 technology has been completed, initially used to manufacture 3D TLC flash memory, single chip capacity 256Gb, but the yield is high enough Afterwards, it will shift to higher-capacity 3D TLCs and eventually manufacture 3D QLCs with capacities up to 1Tb. In addition, Samsung is also developing QLC NAND chips, which will achieve this goal in the fifth-generation NAND technology.

China's storage needs to keep up with the pace of international technology, whether it is the launch of 3D stacking or QLC. These conditions all point out that as 3D NAND technology becomes practical, international manufacturers are accelerating technological advancement. 3D NAND is a relative one for 2D NAND. Flash memory technology changes. And different from micro-plane-based flash memory, 3D memory key technology is the thin film and etching process, the technology process is quite different, and compared to 2D NAND, the international manufacturers to walk in the 3D memory layout It is not far. From the current situation, it is clear that international manufacturers have also recognized this problem and are increasing their efforts in R&D in order to compete for highs in the new period; at the same time, they increase input in production capacity and mass production. , Strive to open distance with the pair.

At present, China's investment in 3D NAND companies is mainly based on the storage of the Yangtze River. The current progress of the project is also very fast. According to the published data, by the end of December 2016, the national memory base led by Yangtze River Storage was formally grounded, expected to be divided into three. At the stage, three 3D NAND plants will be built. In September 2017, the first phase of the plant was capped in advance; in November, 32-layer 3D NAND chips were successfully developed; on April 11, 2018, production equipment was officially installed.

Ziguang Group Chairman Zhao Weiguo, chairman of Changjiang Storage, stated at the installation ceremony that the Wuhan Yangtze River Storage Base will raise 80 billion yuan in funds, and the amount will be fully available. This year it will enter small-scale mass production and enter 128Gb of 3D NAND 64-layer technology next year. R&D. Gao Qiquan, executive vice president of China Unicom Group and executive chairman of Changjiang Storage, disclosed that the Yangtze River's 3D NAND flash memory has received the first order, a total of 10776 chips, will be used for 8GB USD memory card products.

Ye Tianchun, director of the Institute of Microelectronics of the Chinese Academy of Sciences, stated: 'Mainstream memory products have standardized characteristics of bulk products, so the competition in this market is even fiercer. The success of a company often depends on the speed of technological progress and the amount of capital invested. If companies can't keep up with the pace of technological upgrading, they will soon be eliminated. ' Ye Tianchun also stressed the unique structure of products, the importance of enterprise-specific process technology development, in order to deal with international technology competition. 'A storage plant production line is not All will use general equipment. After the initial stage of development, the company will inevitably develop some unique process technologies, and at the same time, it will need to customize the process equipment. I think that after 3 to 5 years, the Chinese storage companies should After this step, it will be difficult to form its own customer base. To complete the customization of process equipment, the development of domestic equipment companies is very important.' Ye Tianchun pointed out.

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