Where it fits in an AI server rack
Markets FCBGA substrates from 8 × 8 mm to 110 × 110 mm, with structures up to 10/n/10 and 8/8 µm line and space, used for 2.5D and chiplet packaging, for HPC and AI server/switch applications (product page). ASE’s 2025 Form 20-F names Unimicron among a limited number of IC substrate suppliers.
What the evidence establishes
AI-rack evidencePositioning: Unimicron’s FCBGA page lists HPC and AI server/switch applications and 2.5D/chiplet packaging, with no named customer.
An explicit AI-server or AI-rack product, design-in, supply role, program, reference design or partnership, such as a part named for rack-scale AI systems or a product sold for AI data centers. For a rack builder, it means the company’s own AI servers or racks. This does not establish revenue, market share, volumes or future sourcing.
| Component role | FCBGA substrates marketed for AI servers and switches |
|---|---|
| Evidence | Positioning: Unimicron’s FCBGA page lists HPC and AI server/switch applications and 2.5D/chiplet packaging, with no named customer. |
| How we know | Positioning A dedicated AI-server or AI-data-center product or reference design, with no named customer. Marketed for AI racks; not a disclosed design win. |
| Primary source | Unimicron Technology — supporting disclosure Company or official disclosure; vendor claims are attributed to their source. |
| Checked | . This is the research review date, not the source publication or quote time. |
Keep in perspective
No named AI customer in the sources captured; any NVIDIA role is reported only. Unimicron also makes HDI and other PCBs, which are not mapped here.
Diversified business exposure. This describes the breadth or role of the business; it is not an investment rating. An AI-server product, design-in or partnership does not by itself establish material AI-rack revenue, market share, or future returns.
Connections to the assembly
These links explain the technology relationship. The model is illustrative and does not represent an actual manufacturer’s bill of materials.
ABF package substrate
A large multilayer organic substrate made with build-up film. It fans the interposer’s dense connections out to the pitch of the board and carries power to the dies.
Scope of the company links: ABF (FCBGA) package substrates. Ibiden (strong GPU demand, substrates for AI servers and switching ICs) and Samsung Electro-Mechanics (FCBGAs for AI accelerators and server CPUs) disclose AI-accelerator substrate supply without naming customers. Unimicron markets FCBGA for AI servers and switches, and Nan Ya PCB is developing large, high-layer substrates for AI and HPC (positioning). Kinsus is named by ASE as an IC substrate supplier, with no AI program documented. Ajinomoto supplies the ABF insulating film to substrate makers and is an upstream enabler, not a substrate maker. Which substrate maker supplies a given GPU is reported, not disclosed.
Related research
Companies with overlapping sector exposure. Their products and evidence may differ; this is not a list of equivalent investments.
- A
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AI-rack evidence - Al
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AI-rack evidence - Am
Amkor Technology
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AI-rack evidence - AH
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AI-rack evidence - B
Broadcom
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AI-rack evidence