Semiconductor Substrates & Interposers
Substrates and interposers are the foundation of modern semiconductor packaging. They provide the mechanical support, electrical pathways, and power delivery between chips and printed circuit boards (PCBs). For traditional packages, organic substrates dominate. For advanced packaging, silicon interposers and emerging glass substrates enable 2.5D/3D integration with thousands of high-density interconnects. Supply of these materials has become a critical bottleneck for GPUs, AI accelerators, and advanced SoCs, making substrates and interposers one of the most strategic leverage points in the semiconductor supply chain.
Role in Packaging
- Provide mechanical stability for mounted dies and interconnects.
- Distribute signals and power between the chip and the system PCB.
- Enable advanced packaging such as 2.5D interposer-based integration.
- Constrain industry growth when supply of ABF substrates or silicon interposers is limited.
Types of Substrates & Interposers
- Organic Substrates: Made of build-up films (e.g., Ajinomoto ABF), widely used in CPUs, GPUs, and networking chips.
- Ceramic Substrates: High-reliability packages for RF, aerospace, and military applications.
- Silicon Interposers: Used in 2.5D packaging (TSMC CoWoS, Intel EMIB) to connect logic and HBM dies.
- Glass Substrates: Emerging alternative with high dimensional stability for future HPC packaging.
Substrate & Interposer Mapping
| Type | Function | Key Vendors | Notes |
|---|---|---|---|
| Organic Substrates | Mainstream packaging base for CPUs, GPUs, ASICs | Ibiden, Shinko, Unimicron, Nan Ya PCB | Dependent on Ajinomoto Build-up Film (ABF) |
| Ceramic Substrates | High-reliability RF, aerospace, defense packages | Kyocera, NGK, CoorsTek | Smaller share but critical for rad-hard chips |
| Silicon Interposers | 2.5D integration with TSVs | TSMC, Samsung, Intel (EMIB) | Enables HBM + logic integration for AI GPUs |
| Glass Substrates | Emerging alternative to organic substrates | Samsung, Intel, Corning | Promising for future HPC packaging |
Risks & Bottlenecks
- ABF Shortages: Limited Ajinomoto ABF capacity has constrained GPU and CPU packaging supply.
- High Barrier to Entry: Few vendors control advanced organic substrate manufacturing.
- Interposer Capacity: Silicon interposers require high-precision TSV processing, concentrated in TSMC and Samsung.
- Technology Transition: Glass substrates are promising but not yet mature for volume deployment.
KPIs to Track
- Layer Count: Build-up layers in organic substrates enabling signal routing density.
- Warpage (µm): Dimensional stability during reflow and operation.
- Interconnect Density: Micro-bumps or TSVs per mm² in interposer technology.
- Supply Concentration: Vendor market share of ABF and interposers.
Market Outlook
The global semiconductor substrate market was valued at ~$12B in 2023 and is projected to exceed $20B by 2030, with ~7% CAGR. Organic substrates remain dominant, but silicon interposers are expanding rapidly due to AI/HPC demand for HBM integration. Ajinomoto’s ABF material remains a critical bottleneck, with new capacity investments planned but unlikely to ease constraints before 2026. Glass substrates are being piloted by Samsung and Intel as a potential next-generation solution for datacenter chips.
FAQs
- What is ABF? – Ajinomoto Build-up Film, an organic resin material used in most high-end semiconductor substrates.
- Why are interposers important? – They enable high-bandwidth interconnects between logic and HBM memory dies, essential for GPUs and AI accelerators.
- Will glass substrates replace organic? – Possibly in HPC, but glass is still in early R&D and not in volume production.
- Who dominates substrate supply? – A handful of Japanese and Taiwanese firms control most of the global market, with Ajinomoto as the sole ABF supplier.
