New variables in the storage market

According to the Wall Street Journal, people familiar with the matter pointed out that both Micron Technology and Western Digital are interested in acquiring Kioxia Holdings Corp. The transaction may increase the valuation of the Japanese semiconductor company to around US$30 billion.

If this deal is reached, it means that Japanese storage manufacturers will disappear from the ranks of storage giants.

In addition, previous anandtech reports showed that Micron Technology stated that the company has stopped all research and development of 3D XPoint storage technology. After Micron exits, Intel will become one of the few companies in the market to promote the development of 3D XPoint.

This shows that a new storm is brewing in the storage market.

Changes brought about by the commercialization of emerging storage technologies

Memory is one of the key components of modern information systems. The size of the storage market dominated by DRAM and NAND Flash has exceeded 160 billion U.S. dollars. With the continuous improvement of processor performance, meeting the market's demand for speed and capacity, and breaking the limitation of the "storage wall", the industry began to try to break through the von Neumann architecture. As a result, emerging storage technologies entered the market's sight. Inside.

MRAM, RRAM and PCRAM are regarded by the industry as the three emerging storage technologies. The emergence of these technologies has not only attracted the attention of established storage vendors, but also attracted the participation of some new players. With their joint promotion, emerging storage technologies have gradually entered the commercialization stage in recent years. In this process, emerging storage technologies ushered in a new round of changes in the storage market.

Compared with DRAM, PCRAM can provide lower power consumption and cost, and has higher performance than solid-state hard drives and hard drives. As a result, it has also attracted the attention of some manufacturers. 3D XPoint, jointly launched by Intel and Micron, is a non-volatile storage technology, which is also considered a technology based on phase change storage. Although Intel has denied that 3D XPoint is a phase-change memory, PCRAM technology has begun to be noticed by the industry. Part of the reason is actually due to the introduction of products based on 3D Xpoint technology by Intel.

3D XPoint is one of the emerging storage technologies. From the perspective of its commercialization process, Intel took the lead in completing the commercialization of 3D Xpoint in 2017 and launched Optane. In November 2019, Micron finally produced its own QuantX. But as Micron ceased research and development of 3D XPoint storage technology, this also means that there is one less player in this emerging storage technology field. The reason why Intel is still obsessed with the development of 3D XPoint storage technology is also partly because the technology fits the needs of the data center, and this is also in line with Intel's development strategy. As storage is one of Intel's six major technologies, the development of emerging storage technologies may differentiate Intel's architecture and form unique advantages.

Another thing worth noting is the development of MRAM. The industry believes that in addition to its better storage performance, MRAM is more importantly that today's processor (CPU) manufacturing process is constantly moving towards miniaturization to meet the demand for high-speed computing. Therefore, MRAM has attracted the attention of many manufacturers, and some variants have been produced in this process, including STT-MRAM, SOT-MRAM, etc. In the development process of MRAM, the joining of several foundries such as TSMC, Samsung and GlobalFoundries is also regarded by the industry as a huge change in the memory market.

However, according to some documents in the IEDM meeting last year, although MRAM technology is favored by the industry, from the perspective of commercialization, its development path is still full of challenges. From this, perhaps we can understand it as, in the process of commercialization of MRAM, the market will also carry out a big wave of related companies.

Challenges faced by mainstream storage technologies

Emerging storage technologies have injected new power into the storage market. In the process of new technology iterations, established storage giants must not only face the development of new technologies, but also face the problem of continuing development of existing mainstream storage technologies.

Among the current mainstream storage, the development of 3D NAND has attracted the attention of the industry. With the continuous advancement of storage giants, after they have pushed 3D NAND to 128 layers in 2020, companies such as SK Hynix and Micron have ran to 176 layers. The eetimes Japan report pointed out that storage vendors will begin mass production of new products launched in 2020 in 2021. The production of the newer next-generation will begin at the end of 2021 and early 2022, which means that in 2022, storage giants will begin mass production of 160- to 192-layer products. By 2023, super high-rise 3D NAND flash memory with more than 200 layers will appear in the market.

In the rapid development of 3D NAND, how to further increase the density of 3D NAND flash memory has become the focus of the market. Storage manufacturers usually use stacked peripheral circuits and memory cell array-related technologies to achieve this goal. Among them, the alliance between Micron Technology and Intel took the lead in commercialization, and then SK Hynix and Yangtze River Storage also adopted similar methods.

Specifically, the method adopted by Intel and Micron is called CUA (CMOS Under Array). This technology is also known as the unique technology of the floating gate method. This technology can put most of the peripheral circuits of NAND chips in the storage. Units are placed below the vertical stack, rather than side by side. According to the news on ISSCC 2021, this change saves a lot of die space and allows more than 90% of the die area to be used for memory cell arrays. In addition, other companies have adopted charge trap (CT) technology. SK Hynix is the first to commercialize this storage technology. The technology it launched is called "PUC (Periphery Under Cell). According to a report from eetimes Japan, although the name is different, it is basically the same technology as CUA. .

As Intel sold its NAND memory business to SK Hynix for US$9 billion in October last year, floating gate NAND may come to an end (before Micron also used floating gate technology, but it is in the process of developing to 176 layers. In China, Micron will transition NAND cell technology from a traditional floating gate to a charge trap). At the same time, due to the difference between CUA technology and SK Hynix’s PUC technology, floating gate NAND may face the stage of withdrawing from NAND. The report also said that SK Hynix announced that they will continue to be the two to the future. Three generations develop floating gate technology, but it does not rule out that the company will prepare for abandoning floating gate technology.

In addition, what needs to be mentioned is the 3D Xtacking architecture launched by the local manufacturer Yangtze Storage. With this, local storage manufacturers have also stepped into a new level and become a new force that cannot be ignored in the storage market. And its Xtacking is another development route that is different from SK hynix technology-Xtacking architecture, which puts the peripheral circuit on the storage unit (this is in line with the 4D flash memory technology launched by SK hynix). On the contrary), to achieve a higher storage density than traditional 3D NAND. There have been reports evaluating these two technologies, saying that Yangtze River Storage’s Xtacking puts more emphasis on storage density and high-speed I/O, while SK Hynix’s 4D flash memory puts more emphasis on integration and cost.

The etimes Japan report also stated that Samsung Electronics and the Kioxia-Western Digital alliance are expected to adopt technologies similar to CUA and PUC in future products. It will become a universal technology for the entire 3D NAND flash memory industry.

In addition, 3D NAND is also facing a transition from TLC to QLC, which is also regarded as a way to reduce the cost of 3D NAND.

According to related reports, QLC technology began commercial production in 2018. In theory, the storage density of the memory cell array can be 1.33 times that of TLC, and the manufacturing cost per storage capacity will be reduced by 25%. The eetimes Japan report pointed out that the transition from TLC to QLC is expected to take about 7 to 8 years, and the QLC method will eventually become the mainstream of bit conversion. In 2021, on a bit-by-bit basis, the QLC method will account for about 15% of NAND flash memory. It is estimated that by 2025, the QLC method will account for about 50% of the bit conversion. In addition, there is a "PLC (five-level storage unit)" technology that can store 5 bits in a storage unit.

At the same time, as the number of stacked layers increases, storage OEMs will have to face increasingly complex and expensive processes. Therefore, storage giants also face challenges in the process of storage products. During this process, EUV began to be introduced by storage vendors into their new product lines, which has also become a competitive point for storage giants in the process of developing new technologies.

From the perspective of the layout of the storage giant’s EUV production line, according to related reports, as Samsung DRAM introduces the EUV process, SK Hynix has also established a research team to conduct research on EUV lithography-related technologies and plan to apply it. The latest DRAM production line is expected to be introduced and applied in the newly built M16 factory in Icheon, South Korea, or a mixed production factory of NAND Flash and DRAM like M14. The final production will depend on market conditions and technological development.

In addition, according to the future plan of SK Hynix products announced by SK Hynix CEO Li Xixi at the IEEE International Reliability Physics Symposium (IRPS), they will use EUV lithography produced DRAM and 600-layer stacked 3D NAND.

Capacity wrestling

In addition to competing in technology, major storage vendors have also launched a race in production capacity.

According to the latest public news, South Korea has granted final approval to SK Hynix’s 120 trillion won (US$106 billion) new project recently. The new project is located in Yongin City, about 50 kilometers south of Seoul. Yongin will serve as the base for DRAM and SK Hynix's next-generation memory chips. In addition, according to SK hynix, Cheongju, located 137 kilometers south of the capital, will become the center of NAND flash memory chips. In response to SK Hynix's layout in South Korea, South Korea said that the latest investment is expected to alleviate the supply shortage in the global market. The ministry added: “As the chip industry is a key pillar of the country’s exports, the government will spare no effort to resolve any potential problems in the entire project so that construction can begin as planned this year.”

As for Samsung, according to reports from South Korean media, Samsung Electronics is increasing its investment in semiconductors and speeding up equipment installation. Samsung will increase the DRAM production capacity of the Pyeongtaek No. 2 plant in the first quarter from the originally planned 30,000 pieces/month to 40,000 pieces/month. Therefore, the additional investment in Pyeongtaek No. 2 factory will expand Samsung's DRAM production capacity from 60,000 to 70,000 in 2021. In addition, according to previous news, Samsung Xi’an (China) 12-inch flash memory chip phase II project will also officially start. The company will invest 8 billion US dollars in a new factory, which is expected to be completed in the second half of 2021, which will also guarantee Samsung's supply of storage capacity.

Domestically, according to the Nikkei Asian Review quoting an unnamed source, Yangtze River Storage plans to double its production this year and plans to increase its monthly memory chip output to 100,000 wafers in the second half of the year, accounting for approximately the world's total 7% of the total output. This will help the company close the gap with advanced global manufacturers. In addition, the report also said that Yangtze River Storage will also prepare for trial production of 192-layer NAND flash memory chips, which will be trial production in mid-2021 at the earliest, but the trial production plan may be postponed to the second half of 2021.

From this market situation, we see that the competition among storage vendors has become more intense, and some technologies will gradually withdraw from the arena of the storage market under the change, which has also triggered some changes in the storage market. On the other hand, in order to grab more market share, major storage vendors are also starting to compete for production capacity. Under the combined effect of these factors, the storage market has also begun a new round of changes.