sk hynix hbm memory technology and supply chain

hbm constrains ai chip production. memory bandwidth determines performance limits for large language models and training workloads.

hbm technology fundamentals

architecture

hbm stacks dram dies vertically:⁶

through-silicon via (tsv)

hbm tsv specifications:

• tsv density: 4,000-8,000 vias per die
• via diameter: 5-10 μm
• pitch: 40-50 μm
• aspect ratio: 10:1 to 20:1
• electrical path: 50-100 μm through silicon

tsvs provide vertical interconnection.

thermal management

sk hynix’s proprietary mr-muf (mass reflow molded underfill):²

• reduces chip stacking pressure by 6%
• increases productivity 4x through reduced process time
• improves heat dissipation by 45% vs traditional underfill
• advanced mr-muf adds 10% additional thermal improvement

required for 700w+ accelerator thermal management.

sk hynix market position

competitive position

production capacity and expansion

m15x: hbm-specific fab with euv capability.⁴

financial performance

hbm revenue and projections:

• 2024: $8-10 billion hbm revenue
• 2025: $12-15 billion projected (sold out)
• 2026: $18-22 billion with m15x ramp
• gross margin: 50-60% on hbm vs 20-30% on commodity dram
• price premium: 5-8x per gb vs standard dram

sk hynix ceo kwak noh-jung: “sold out of hbm production for 2024 and almost sold out for 2025”¹

manufacturing ecosystem

equipment suppliers

hbm production equipment:⁷

materials

hbm manufacturing materials:⁷

• ncf (non-conductive film): die attachment and insulation
• tim (thermal interface material): heat dissipation between layers
• mr-muf materials: sk hynix proprietary underfill
• photoresists: for tsv and redistribution layer patterning
• seed layers: copper/titanium for tsv metallization

japanese suppliers dominate specialized materials.

test and validation

hbm test requirements:

• known good die (kgd): pre-stacking test
• mid-bond testing: assembly validation
• final test: bandwidth and thermal
• burn-in: temperature aging
• system-level validation: gpu configuration test

testing: 15-20% of total cost.

competitive landscape

samsung memory

samsung hbm status:⁵

• yield issues: 10-20% lower yields than sk hynix on hbm3e
• thermal problems: inferior heat dissipation in nvidia qualification
• market share: declining from 40% to ~35%
• customer concentration: lost nvidia h200 to sk hynix exclusive

samsung investing in yield improvements.

micron technology

micron hbm position:⁸

• hbm3e production: ramping in late 2024/early 2025
• capacity: targeting 20% market share by 2026
• differentiation: focus on power efficiency
• customers: amd, potential intel discrete gpus
• us advantage: domestic supply for government contracts

chinese development

china hbm status:⁹

• cxmt (changxin memory): developing hbm2 equivalent
• technology gap: 3-4 years behind leaders
• equipment constraints: lack of advanced equipment access
• target market: domestic ai chips, import substitution

limited competitive impact through 2028.

supply chain dynamics

vertical integration

memory manufacturer expansion:

• sk hynix: investing in packaging equipment and materials
• samsung: developing in-house test capabilities
• micron: partnering with osats for turnkey solutions

increasing supply chain integration.

geographic concentration risks

pricing and allocation

hbm pricing dynamics 2025:

• spot prices: 50-100% premium over 2023 levels
• contract pricing: annual agreements with 20-30% increases
• allocation priority: nvidia > amd > custom chips > others
• prepayment requirements: major customers paying 12+ months ahead
• minimum orders: 10,000+ units for direct supply

supply constraints through 2026.

technological roadmap

hbm4 (2026-2027)

hbm4 specifications:¹⁰

• bandwidth: 1.6-2.0 tb/s per stack
• capacity: 48-64 gb per stack
• interface: 2048-bit wide bus
• power efficiency: 30% improvement per gb/s
• new features: on-die ecc, ai-specific operations

sk hynix targeting q4 2026 for initial production.

packaging evolution

hbm packaging roadmap:

• hybrid bonding: direct cu-cu connections replacing micro-bumps
• silicon bridges: connecting multiple hbm stacks
• optical interconnects: photonic links for extreme bandwidth
• advanced cooling: integrated microfluidic channels
• chiplet integration: hbm as standardized chiplet

future memory technologies

• pim (processing in memory): computation within memory stack
• cxl-attached memory: disaggregated memory pools
• persistent memory: storage-class memory integration
• 3d xpoint successors: new non-volatile technologies
• quantum memory: cryogenic memory for quantum computers

ai workload optimization

workload requirements

software optimization

hbm utilization techniques:

• data layout: optimizing for 1024-bit access patterns
• prefetching: hiding latency through prediction
• compression: reducing bandwidth requirements
• caching: intelligent use of on-chip sram
• scheduling: maximizing concurrent memory operations

software optimization: 2-3x effective bandwidth improvement.

market outlook

market projections

hbm market size:¹¹

• 2024: $12 billion market
• 2025: $18 billion (50% growth)
• 2026: $28 billion (55% growth)
• 2028: $50 billion projection
• 2030: $80-100 billion potential

ai accelerators: 85%+ of demand.

semiconductor implications

• memory equal partner with logic in ai chips
• vertical integration between memory and gpu makers
• new business models around bandwidth-as-a-service
• shift from commodity to specialized memory products
• geographic diversification

capital requirements

hbm investment scale:

• new fab: $15-20 billion for advanced memory fab
• conversion cost: $2-3 billion to convert dram to hbm
• r&d spending: 15-20% of revenue vs 10% for commodity
• equipment: 30% more expensive than standard dram tools
• time to market: 3-4 years from greenfield to production

limited to major memory manufacturers.

references

[1] anandtech. (2025). sk hynix reports that 2025 hbm memory supply has nearly sold out.

[2] sk hynix news. (2025). sk hynix begins volume production of the world’s first 12-layer hbm3e.

[3] videocardz. (2024). sk hynix hbm3e volume production starts 1h24, in time for nvidia gh200 grace hopper.

[4] digitimes. (2025, may 2). sk hynix says 2025 hbm production almost sold out.

[5] tom’s hardware. (2025). hbm supply from sk hynix and micron sold out until late 2025.

[6] semianalysis. (2025, august 12). scaling the memory wall: the rise and roadmap of hbm.

[7] digitimes. (2024, april 24). japanese materials and equipment suppliers gaining from hbm expansion drive.

[8] tweaktown. (2025). sk hynix, samsung, micron are expanding hbm production.

[9] techpowerup. (2025). sk hynix ceo says hbm from 2025 production almost sold out.

[10] sk hynix news. (2025). sk hynix develops industry’s first 12-layer hbm3.

[11] investing.com. (2025, august 21). broadcom raises ai revenue forecast on strong custom chip demand.