CXMT’s 4F² DRAM Plan Jolts Korean Chipmakers

Semiconductor wafers produced by ChangXin Memory Technologies (CXMT) are on display at the 2026 World Manufacturing Convention held at the Binhu International Convention Center in Hefei, the capital city of Anhui Province, China. (Yonhap) As China’s largest memory semiconductor company, ChangXin Memory Technologies (CXMT), announced the release of server DRAM applied with the next-generation DRAM cell structure ‘4F² (Four F Square)’ new technology within this year, the global semiconductor market has plunged into a fierce storm. The high-performance memory market for servers is a core territory that has been led by a few semiconductor giants in South Korea and the United States, such as Samsung Electronics, SK  hynix, and Micron. As China’s CXMT, which has mainly focused on producing general-purpose products, threw down the gauntlet in this area, fears spread that the memory technology gap is narrowing much faster than expected. In the aftermath, a massive shockwave was created in the domestic stock market, freezing investor sentiment as Samsung Electronics and SK hynix faced record plunges reaching the 7% range and the 10% range, respectively. Amidst this escalating sense of crisis in the market, Song Jae-hyuk, President and Chief Technology Officer (CTO) of the Device Solutions (DS) Unit at Samsung Electronics, stepped in to extinguish the fire at the 28th Semiconductor Exhibition (SEDEX) held at COEX in Seoul on Oct. 14. When asked by reporters whether Samsung Electronics is also developing 4F², President Song clearly answered, “Yes.” Regarding the progress of the development, he spared his words, stating, “We are working hard,” but implied that the domestic industry has also already been preparing the corresponding technology from multiple angles. In fact, 4F² is a technology that the domestic semiconductor dual carriage, Samsung Electronics and SK hynix, have early on researched as a core pillar of future processes. SK hynix previously revealed its plan to introduce the 4F² VG (Vertical Gate) platform in the sub-10-nanometer segment at a symposium, and Samsung Electronics also successfully manufactured a 16Gb DRAM test chip with a 4F² structure and achieved actual operation at the International Solid-State Circuits Conference. Does CXMT’s forecasted release within this year immediately mean the overtaking of South Korea’s technology? Experts point out the need to coldly examine the truth and falsehood of the announcement’s contents. According to academic experts, the plan announced by CXMT entirely omits expressions such as full-scale mass production or sample supply. Even the specific product specifications or release schedules containing the reality of commercialization have not been disclosed. Therefore, analysis suggests it is reasonable to interpret this not as a signal flare for full-scale mass production, but as a release preview tinged with political and marketing purposes. Since server DRAM must go through difficult yield securing and strict quality certification processes by major client companies apart from prototype production, the timing for large-scale mass production in a practical sense is predicted to be possible at the end of 2027 or the first half of 2028 at the earliest. 4F² is a technology that drastically reduces the area occupied by a single memory cell. F is the minimum line width that serves as the standard for circuit processing, and compared to the current mainstream 6F² (width 3F and length 2F), 4F² (width and length 2F each) reduces the area by about 30% and improves the theoretical integration density by 50%. However, changing the structure does not immediately mean the realization of ultra-high integration. While the line width of the 4F² cell that China’s CXMT intends to apply is currently at the 15-nanometer (nm) level, the current 6F² cell focused on by the domestic memory industry is at the 12.2-nanometer level, keeping the actual integration density realized by the two technologies at a similar level. Although China is breathlessly chasing through structural reorganization, the prevailing diagnosis is that it is unreasonable to conclude that they have surpassed South Korea by more than two years in terms of technical completeness. Behind CXMT throwing the 4F² winning move lies the United States’ high-intensity export controls on extreme ultraviolet (EUV) lithography equipment. While Samsung Electronics and SK Hynix draw fine circuits through advanced EUV equipment, China is blocked from securing EUV and must rely on multi-patterning, which repeatedly overlaps and engraves circuits using deep ultraviolet (DUV) equipment. Choosing the smaller-area 4F² structure becomes a realistic escape route for China because it allows them to bypass and achieve a certain level of integration density even with a relatively large line width. However, as the price for not being able to use EUV, it is difficult to make vertical channel transistors uniform, and numerous difficult challenges are blocking the way, such as current leakage, the floating body effect, and wafer bonding. For this reason, technological pessimism coexists, suggesting that the initial yield could fall below 10%. However, leading semiconductor scholars warn that as China experiences these difficult challenges as if banging their heads against a brick wall, they could gain unexpected nourishment in the future next-generation three-dimensional (3D) DRAM competition. It is a stark reality that the time gap South Korea has earned due to US sanctions is gradually narrowing. The fact that domestic semiconductor leaders, including the Samsung Electronics CTO and the SK hynix President of Development, toured partner booths together and strengthened their solidarity at the event venue also reflects this sense of crisis. Currently, to counter China’s pursuit, the South Korean semiconductor camp is staking its life on ultra-gap technologies for high value-added AI memory, such as the HBM5 conceptual model beyond the 7th generation High Bandwidth Memory (HBM) HBM4E, and technology that combines AI computation functions into memory. As China has chased right up to the chin with a structural transformation that bypasses EUV sanctions, it is time for the government and the industry to move beyond simple fear and further accelerate overwhelming yield competitiveness and the speed of developing next-generation source technologies.