DEEP RESEARCH · SEMICONDUCTORS / HBM4
HBM4: Samsung vs. SK hynix, and Custom HBM
The sixth-generation HBM transition for AI accelerators: yield, logic base dies, hybrid bonding, and cHBM strategy
0. Bottom line first
The HBM4 war favors SK hynix in near-term yield stability, while Samsung has greater long-term performance upside if it succeeds with both 1c DRAM and hybrid bonding. The winner is not the first sampler, but the company that stabilizes high-quality, high-yield mass production first.
Official fact: The source says HBM4 features an I/O interface doubled from 1024-bit to 2048-bit and a base die integrating logic process technology, and is expected to command more than a 30% price premium over HBM3E.
1. HBM4 Competitive Landscape
Defensive strategy
Supplied 12-high HBM4 samples to major customers in March 2025 and targets mass production in the second half of 2025, using 1b DRAM and Advanced MR-MUF to reduce transition risk.
Challenger strategy
Plans customer sample shipments in July 2025 and takes a high-risk, high-reward path by introducing both 1c DRAM and hybrid bonding.
Pragmatic strategy
Shipped 12-high 36GB HBM4 samples in June 2025, targets 2026 production, and claims more than 20% power-efficiency improvement over HBM3E.
| Company | DRAM process | Base die | Packaging / strategy | Main risk |
|---|---|---|---|---|
| SK hynix | 1b | TSMC partnership | Advanced MR-MUF, yield first | TSMC dependence and next-step speed |
| Samsung | 1c | In-house 4nm foundry | Hybrid bonding, turnkey | Cumulative yield across 1c and bonding |
| Micron | 1-beta | TSMC partnership | Power efficiency and U.S. supply chain | Customer qualification and volume versus leaders |
2. Technology Split: 1b Stability vs. 1c Leap
SK hynix and Micron use mature 1b-class DRAM processes already used in HBM3E production, reducing DRAM-side manufacturing risk. Samsung applies next-generation 1c DRAM to HBM4. If it works, Samsung can gain fundamental advantages in performance, power efficiency, and density. The source says early 1c yields were below 30% but have reportedly improved to the 50-70% range in recent tests.
3. Logic Base Die and Foundry Dynamics
The HBM4 base die evolves from simple signal transfer to a logic-integrated layer. The 2048-bit interface, signal integrity, lower latency, and data-path efficiency require it. SK hynix and Micron use TSMC, while Samsung aims to produce logic base dies internally on its 4nm process.
Interpretation: This is where Samsung’s IDM advantage can matter. A turnkey bundle across DRAM, logic design, foundry, packaging, and testing is attractive to customers such as Google, Microsoft, and Meta that want customized HBM. But if yield fails, integration becomes a bottleneck rather than an advantage.
4. Hybrid Bonding as a Double-Edged Sword
The source argues Samsung’s competitiveness depends on simultaneously succeeding with 1c DRAM and hybrid bonding. These technologies can provide performance, density, and power-efficiency advantages if successful, but two unproven, difficult processes can create a cumulative-yield problem in the short term. Samsung’s new technology is both the long-term path to victory and the near-term vulnerability.
5. Rise of Custom HBM
Alongside standard JEDEC HBM, custom HBM, or cHBM, is emerging for customer-specific AI accelerators. The source says customized interfaces and base-die designs maximize PPA, can use up to 25% silicon area freed by shrinking the memory I/O interface or increase the number of HBM stacks by 33%, and can reduce power consumption by up to 70% versus a standard HBM interface.
Integrated turnkey
Offers vertical integration across 1c DRAM, in-house 4nm foundry, hybrid bonding, and advanced packaging.
Collaborative ecosystem
Focuses on DRAM and MR-MUF strengths while partnering with TSMC for custom logic base dies.
Fast follower
Targets hyperscale customers through TSMC cooperation and its Cloud Memory Business Unit.
6. Watch Points
- Samsung: quarterly 1c DRAM yield maturity, HBM 4nm logic-die yield, SAINT-D hybrid-bonding line yield, and Nvidia qualification timing
- SK hynix: HBM4 mass-production timing, committed supply volume, HBM4E hybrid-bonding roadmap, and further performance gains through TSMC
- Micron: customer qualification before 2026 production, power-efficiency differentiation, and U.S. supply-chain premium
HBM4 is entering one of the most technically interesting phases in memory. SK hynix defends its lead with careful engineering; Samsung bets heavily on next-generation technology. The result will come down to manufacturing execution and yield.
Sources
- Original Naver Blog post: https://m.blog.naver.com/PostView.naver?blogId=star_of_self&logNo=223913764185