Why ABF Substrates Are Essential for High-Performance Chips

Introduction: The Growing Importance of ABF Substrates

The Demand for High-Density Packaging and Miniaturization

As semiconductor devices continue to shrink while increasing in complexity, traditional PCB substrates struggle to meet the demands of modern electronics. Advanced packaging solutions require substrates with higher interconnect density, lower signal loss, and improved thermal properties.

Why ABF Substrates Are Essential for Modern Semiconductor Devices

Ajinomoto Build-up Film (ABF) substrates have become a preferred choice for high-performance applications due to their ability to support fine-line routing, microvias, and multi-layer stacking. These features allow semiconductor companies to integrate more transistors and improve power efficiency, making ABF substrates essential for advanced chips used in AI, HPC, and networking.

Evolution of ABF Substrates in Advanced Electronics

Initially developed to support high-density interconnects in flip-chip packaging, ABF substrates have evolved alongside the semiconductor industry. Today, they are a critical component in high-end processors, GPUs, FPGAs, and 5G infrastructure, enabling next-generation computing power and communication speeds.

ABF Substrate vs. Other Substrate Technologies

Comparison with BT Resin Substrates and Conventional PCB Materials

• BT (Bismaleimide-Triazine) resin substrates have been widely used for lower-cost applications but lack the fine-line resolution needed for high-end semiconductor devices.
• Conventional PCB materials such as FR4 are cost-effective but have high dielectric loss and lower thermal performance, making them unsuitable for high-frequency, high-speed applications.

Key Advantages of ABF Substrates

• Fine-line patterning (below 10µm) enables high-density routing.
• Excellent thermal and electrical performance supports high-speed signal transmission.
• Superior mechanical stability, reducing warpage and enhancing reliability in multi-layer designs.

Limitations and Challenges of ABF Technology

• Manufacturing complexity: The multi-step build-up process requires advanced equipment and precise control.
• Supply chain constraints: Limited ABF material production capacity has led to supply shortages.
• Higher cost compared to traditional substrates: The sophisticated fabrication process increases overall costs.

Key Features and Performance Benefits of ABF Substrates

Fine-Line Routing and Microvia Capabilities for High-Density Interconnects

ABF substrates enable semiconductor devices to achieve ultra-fine line width/spacing, making it possible to connect more I/O pins within a compact footprint. Laser-drilled microvias allow for multi-layer interconnects, which are crucial for packaging high-speed and high-power chips.

Thermal and Electrical Properties Optimized for HPC and AI Applications

• Low dielectric constant (Dk) and low dissipation factor (Df) reduce signal loss, ensuring high-speed data transmission.
• Efficient heat dissipation properties help manage thermal performance in power-hungry chips.
• Stable mechanical properties improve reliability, especially in data centers and automotive environments.

Compatibility with Multi-Chip and Heterogeneous Integration Packaging

As chiplet-based architectures gain popularity, ABF substrates provide the necessary interconnect density and electrical performance to support multi-die integration in advanced packaging technologies such as 2.5D and 3D stacking.

The Role of ABF Substrates in AI, HPC, and Cloud Computing

Increasing Computing Power Demands and Packaging Requirements

AI and HPC workloads require massive data processing capabilities, which drive the need for highly efficient packaging solutions. ABF substrates allow high-speed connections between processing cores, memory, and I/O interfaces, improving overall system performance.

How ABF Substrates Support AI Accelerators, CPUs, and GPUs

• AI accelerators (such as NVIDIA’s GPUs and Google’s TPUs) benefit from the high-speed interconnects enabled by ABF substrates, reducing latency in machine learning workloads.
• CPUs and HPC processors rely on ABF substrates for multi-core integration and efficient power distribution.
• FPGAs used in data centers leverage ABF substrates to achieve high-bandwidth connectivity with minimal power consumption.

Impact on Data Centers, Cloud Infrastructure, and Edge Computing

• Data centers depend on ABF-based processors to handle cloud computing, big data analytics, and AI training.
• 5G edge computing devices use ABF substrates to enable low-latency, high-speed processing in distributed networks.

Supply Chain and Manufacturing Challenges

Global Production Capacity and Material Constraints

With demand for ABF substrates increasing, manufacturers face production capacity limitations. Ajinomoto, the primary supplier of ABF materials, is working to expand its output, but bottlenecks persist.

Key Manufacturers and Geographic Distribution of ABF Substrate Production

• Chinese packaging substrate manufacturers: Qinyuanchun, ALCANTA
• Taiwan-based manufacturers: Unimicron, Nan Ya PCB, Kinsus
• Chinese packaging substrate manufacturers: Qinyuanchun, ALCANTA
• Japanese suppliers: Ibiden, Shinko Electric, Kyocera
• South Korean and Chinese players: Samsung Electro-Mechanics, AT&S, Zhuhai ACCESS

Efforts to Overcome Shortages and Improve Fabrication Efficiency

• Investment in new fabrication facilities to increase ABF substrate production capacity.
• Development of alternative materials to complement or replace ABF in certain applications.
• Optimization of the supply chain to reduce lead times and costs.

Future Outlook: What’s Next for ABF Substrates?

Advancements in Ultra-Fine Line Technology and Multi-Layer Stacking

With semiconductor manufacturers pushing for finer interconnects, ABF substrate technology is expected to evolve toward sub-5µm line/space capabilities and higher layer counts to support next-generation chips.

Potential Competition from Glass and Fan-Out Wafer-Level Packaging

• Glass core substrates are emerging as a possible alternative, offering improved dimensional stability and lower signal loss.
• Fan-out wafer-level packaging (FOWLP) may provide an alternative for some applications, reducing reliance on ABF substrates.

The Long-Term Role of ABF Substrates in Next-Generation Semiconductors

Despite competition, ABF substrates are expected to remain a dominant technology for high-performance computing and AI chips in the foreseeable future, thanks to continuous improvements in materials and manufacturing processes.