CoWoS vs InFO Technology Comparison

An In-Depth Analysis of Two Advanced Packaging Technologies and Their Application Scenarios

Introduction: The Crucial Role of Packaging Technology

As Moore's Law approaches its physical limits, the traditional strategy of boosting chip performance through process node scaling has reached a bottleneck. Consequently, industry focus is shifting toward innovations in chip architecture and breakthroughs in packaging technology—especially solutions enabling heterogeneous integration and system-level modular packaging. "Advanced Packaging" refers to the use of higher-density electrical interconnects, optimized thermal management, and flexible chip placement to extend the performance trajectory historically driven by Moore's Law.

As the global leader in wafer foundry services, TSMC has continued investing in advanced packaging R&D, offering platforms that cover 2.5D, 3D IC, and Fan-Out structures. Among them, CoWoS (Chip on Wafer on Substrate) and InFO (Integrated Fan-Out) stand out as two of the most mature and representative technologies. These are widely applied across high-performance computing (HPC), smartphone SoCs, AI accelerators, and wearable devices.

This article offers an in-depth comparison of CoWoS and InFO, analyzing their design principles, process differences, use cases, and future roadmaps to help engineers build comprehensive technical insight and make informed decisions during packaging selection.

Technology Architecture Overview

To evaluate advanced packaging technologies, it's essential to understand their fundamental structure and design philosophy. CoWoS and InFO each originate from different application demands, reflected in their structural designs, thermal performance, electrical characteristics, and cost efficiency. The following table compares their core technical attributes side-by-side to support engineers in selecting the best solution for specific design needs:

Technology	CoWoS (Chip on Wafer on Substrate)	InFO (Integrated Fan-Out)
Commercial Launch	2012	2016
Packaging Structure	Chips stacked on a silicon interposer, mounted on a substrate	Substrate-less; chips embedded in molded resin with RDL on top
Thermal Performance	Superior; supports high-power designs	Limited thermal dissipation
RDL Density	High; supports multiple RDL layers and TSV	Lower; limited metal stack layers
Main Applications	HPC, AI, data centers	Mobile devices, consumer electronics

In-Depth Analysis: CoWoS

CoWoS is a variation of 3D packaging and represents one of the most mature and critical technologies in the 2.5D IC space. Its core lies in utilizing a silicon interposer as a high-density routing platform, enabling horizontal integration of multiple chiplets—such as logic chips (CPUs or GPUs) and high-bandwidth memory (HBM).

This design delivers massive interconnect bandwidth while significantly reducing signal latency—essential for HPC and AI training workloads. The interposer is made of high-purity silicon and houses tens of thousands of metal traces, supporting micron-level line width and spacing, which further enhances I/O density and signal integrity.

Through-silicon via (TSV) technology enables vertical signal transfer between the interposer and substrate, dramatically shortening electrical paths and improving thermal conduction. CoWoS also supports heterogeneous integration, allowing different process nodes or IP sources to be combined in a single package.

CoWoS is widely adopted in data centers and AI applications. For example, NVIDIA’s H100 uses TSMC’s CoWoS-S technology to integrate six HBM3 dies, achieving over 3 TB/s of memory bandwidth. This packaging approach enables sustained high performance while keeping power consumption and thermal reliability in check.

In-Depth Analysis: InFO

As smartphones, wearables, and IoT devices continue to demand higher performance in smaller form factors, traditional packaging technologies have reached their limits. Conventional substrate-based packages require thick layers and metal bumps, increasing cost and thickness. To address this, TSMC introduced InFO (Integrated Fan-Out) in 2016.

InFO belongs to the Fan-Out Wafer-Level Packaging (FOWLP) category and removes the need for expensive and bulky substrates. Chips are embedded directly into molded resin, and multiple redistribution layers (RDL) are built on top. This design enables highly precise and compact metal routing, shortening signal paths and reducing power consumption and latency.

Advantages:

InFO significantly reduces package thickness, making it ideal for modern mobile devices. By eliminating the need for a substrate, it also reduces overall packaging costs. The short signal paths improve power efficiency and are especially suited for wireless communication devices.

Limitations:

Due to fewer RDL layers, InFO is less suited for complex die stacking or high-density interconnects. Its thermal performance is inferior to CoWoS, as molded resin has low thermal conductivity. It is not ideal for high-power applications (>20W).

Use Cases:

Apple’s A-series processors such as the A12 and A14 use InFO-PoP technology. Qualcomm’s Snapdragon platforms employ InFO-AiP for 5G mmWave chips. Wearables and TWS earbuds also utilize InFO_oS packaging for compact system integration.

Technical Comparison and Selection Guidelines

After understanding the technical details of both CoWoS and InFO, engineers can compare the two across several dimensions—system integration, process flexibility, thermal management, interconnect density, and cost. This helps in choosing the right packaging solution for specific applications, from HPC to mobile electronics.

Category	CoWoS	InFO
Package Density	High	Medium
Cost Structure	High	Medium to Low
Suitable Power Range	Medium to High (>100W)	Low Power (<20W)
Package Thickness	Thick	Thin (<1mm)
Thermal Performance	High	Medium to Low
System Scalability	Excellent (supports 2.5D/3D IC)	Good (lateral + antenna integration)

CoWoS is ideal for applications requiring extreme I/O integration and bandwidth (e.g., AI, HPC), while InFO is better suited for thin, compact, and cost-sensitive devices (e.g., smartphones, wearables).

Future Trends

TSMC is evolving CoWoS into CoWoS-L (Large Interposer), increasing interposer size and signal routing density. This will enable even larger-scale chiplet integration for high-bandwidth, high-power-density use cases such as large AI models and data center workloads.

Meanwhile, InFO is advancing into InFO-MS (Multi-Stack) and InFO-SoW (System on Wafer) architectures. These platforms emphasize vertical integration and modularity. InFO-MS supports advanced die stacking (e.g., memory + logic), while InFO-SoW introduces wafer-level system concepts ideal for low-power, compact applications such as wearables, edge computing, and automotive radar.

In general, TSMC’s packaging roadmap is shifting from chip-level to system-level integration, with thermal, power, and heterogeneous design as central priorities.

Conclusion: Toward System-Level Packaging

While CoWoS and InFO originated from different market needs—CoWoS for extreme HPC performance and InFO for thin and power-efficient consumer devices—their roadmaps are converging. This reflects a broader trend: advanced packaging is no longer a post-fabrication step but a key driver of system performance.

The new paradigm in semiconductors is shifting from single-chip design to multi-die and heterogeneous architecture optimization. Engineers must now evaluate packaging options not only by cost or form factor but also by thermal strategy, signal density, and integration flexibility.

Both CoWoS and InFO have proven themselves in their respective domains. They are foundational technologies in the emerging era of system-level integration and modular design.