The Korean semiconductor industry association estimates the technological gap between China and Korea in memory at approximately three years for HBM, two years for DRAM, and one year for NAND flash memory, which is less than the long-standing discrepancies previously observed in industry commentary. This analysis focuses on the maturity of manufacturing processes compared to manufacturers such as Samsung Electronics and SK hynix, rather than market share or funding competition.
In the DRAM segment, ChangXin Memory Technologies (CXMT) has transitioned from the DDR5 standard to mass production of LPDDR5X and has begun releasing LPDDR6, with Xiaomi named as one of the first smartphone consumers. This pace of mobile DRAM development is the most apparent short-term indicator that CXMT's core process is closing the gap with established competitors regarding traditional products, even though high-performance memory production remains structurally more complex.
The biggest challenges persist in HBM production, where chip yield rates remain low. According to DigiTimes reports, CXMT's early HBM3 yield reached nearly 25%. The main causes of failures are the formation of Through-Silicon Vias (TSVs), multi-layer stacking, and bonding processes. Industry notes often point to thousands of TSV cuts per stack and weak final testing pass rates in early batches. Analyses in the style of SemiAnalysis typically divide this overall figure into a weaker sorting process at the front end and a stronger assembly at the back end, emphasizing that HBM is not just 'DRAM plus stack'; vertical interconnection and the bonding process define the primary learning curve for components eight layers high or more.
To simplify the stacking process without excessive reliance on EUV lithography, CXMT plans to implement DRAM stacks by adopting the experience of the copper-to-copper XStacking hybrid joint from Yangtze Memory Technologies (YMTC). This implies direct Cu–Cu connection instead of relying solely on microbumps between DRAM crystals at CXMT's G4 node (approximately class 1z). YMTC's experience in creating NAND layers serves as a benchmark process; Samsung and SK hynix are mentioned only as technological analogs for measuring gaps. It will be crucial to observe whether the DRAM stacks with hybrid bonding can push HBM yield figures out of the mid-twenties range, which would serve as a concrete process checkpoint separate from any revenue narratives reported elsewhere.