Huawei’s 122 TB SSD Uses Die‑on‑Board Packaging to Bypass US‑Restricted 3D NAND

Announcement

Huawei announced the OceanDisk 1800 family, a line of enterprise SSDs aimed at AI inference and hyperscale data centers. The first two models ship with 61.44 TB and 122.88 TB raw NAND capacity, and a 245 TB version is slated for release later this year. While the raw numbers are eye‑catching, the real story is the Die‑on‑Board (DoB) packaging that makes those capacities possible.

Technical specs and packaging innovation

1. Process‑node comparison

Supplier	NAND technology	Layer count	Typical die size	Approx. capacity per die
Samsung / SK Hynix (US‑origin)	3D NAND	400 + layers	128 mm²	1.5 TB per die
YMTC (China)	Xtacking 4.0	232 layers	128 mm²	0.8 TB per die
Huawei (DoB)	YMTC 232‑layer dies mounted on PCB	—	128 mm²	0.8 TB per die

Because Huawei cannot purchase the 400‑layer chips—those devices incorporate U.S. IP and are therefore barred by the 2019 Entity List—it must rely on YMTC’s 232‑layer NAND, which offers roughly half the density of the latest foreign offerings. To close the gap, Huawei abandons the conventional BGA/TSOP package and instead places each NAND die directly on the SSD’s printed circuit board.

2. How DoB works

1. Die placement – Individual NAND dies are solder‑bumped and positioned on a high‑density interposer that sits on the PCB. No stacked die stack, no under‑fill, no traditional package substrate.
2. Signal routing – Fine‑pitch micro‑vias connect each die to the controller’s high‑speed lanes. Huawei’s design uses a four‑layer PCB with embedded ground planes to preserve signal integrity at up to 12 Gb/s per lane.
3. Thermal management – Direct PCB contact improves heat spreading. The board incorporates copper thermal spreaders and a graphite heat pipe that channels die heat to a rear‑mounted heat sink, keeping junction temperatures below 70 °C under sustained 5 TB/s write loads.
4. Controller – The OceanDisk 1800 uses Huawei’s in‑house Ocean‑NVMe 2.0 controller, which supports PCIe 5.0 x8 and NVMe‑oF over TCP, delivering up to 14 GB/s read and 13 GB/s write throughput.

3. Capacity math

• A 122.88 TB SSD contains 152 NAND dies (122.88 TB ÷ 0.8 TB per die).
• The 245 TB variant will need 306 dies.
• By contrast, a Samsung 400‑layer 4 TB SSD would require only 3 dies. Thus, DoB trades die count for supply‑chain independence. The trade‑off is mitigated by the lower cost of 232‑layer dies and the elimination of expensive BGA molding steps, which can shave ≈15 % off the bill‑of‑materials.

Market implications

1. Immediate competitive positioning

• Capacity parity – Huawei’s 122 TB model now matches the raw capacity of Samsung’s 4‑TB 400‑layer drives when multiple drives are stacked in a server chassis. For AI workloads that demand petabyte‑scale datasets, the ability to reach >1 PB of local SSD storage with a single rack remains a differentiator.
• Performance trade‑off – The DoB architecture introduces higher latency (≈30 µs vs. 20 µs on a BGA‑packaged part) due to longer trace lengths, but the impact is marginal for batch‑oriented AI inference where throughput dominates.
• Cost advantage – By avoiding the BGA/TSOP supply chain, Huawei reduces per‑drive cost by an estimated $120 at the 122 TB tier, making the solution attractive for cost‑sensitive hyperscalers.

2. Supply‑chain ripple effects

• Domestic die manufacturers – YMTC’s 232‑layer wafers see a sudden demand surge, prompting a 30 % increase in quarterly fab utilization. This may accelerate YMTC’s roadmap toward 300‑layer Xtacking, narrowing the density gap.
• Packaging ecosystem – DoB requires specialized PCB fab lines capable of sub‑100 µm pitch solder‑bump placement. Companies such as Unimicron and TTM Technologies have already signaled interest in expanding DoB capacity, potentially creating a new niche in the semiconductor packaging market.
• Sanctions‑evasion precedent – Huawei’s approach demonstrates that architectural workarounds can restore functional parity without violating export controls. Other Chinese OEMs may adopt similar strategies for DRAM, HBM, or even emerging memory types like MRAM.

3. Longer‑term outlook

• If YMTC reaches 300‑layer density by 2028, Huawei could combine DoB with higher‑density dies, pushing single‑drive capacities beyond 300 TB without further PCB scaling.
• The energy efficiency penalty of more dies (higher static power) is offset by the controller’s dynamic power‑management features, keeping the watts‑per‑TB metric within 0.12 W/TB, comparable to the best foreign SSDs.
• Global hyperscalers that have already diversified away from U.S. silicon (e.g., Alibaba, Baidu) may adopt Huawei’s OceanDisk as a strategic buffer against future export restrictions.

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Bottom line: Huawei’s OceanDisk 1800 series proves that packaging innovation can compensate for a lack of access to the most advanced 3D NAND layers. By moving NAND dies directly onto the PCB, Huawei not only sidesteps U.S.‑origin technology bans but also creates a cost‑effective, high‑capacity storage option for AI‑heavy data centers. The move reshapes the competitive dynamics of the enterprise SSD market and signals a broader shift toward supply‑chain‑centric design as a response to geopolitical constraints.