Breakthrough in Semiconductor Packaging: Broadcom Introduces 3.5D Technology

As AI and high-performance computing (HPC) technologies rapidly evolve, traditional semiconductor packaging techniques struggle to meet the increasing demands for performance and efficiency. The era of advanced semiconductor packaging has arrived, with major players like Broadcom making strides in innovative solutions.

As AI and high-performance computing (HPC) technologies rapidly evolve, traditional semiconductor packaging techniques struggle to meet the increasing demands for performance and efficiency. The era of advanced semiconductor packaging has arrived, with major players like Broadcom making strides in innovative solutions.

Broadcom Unveils 3.5D F2F Packaging for AI Applications

Broadcom has introduced its groundbreaking 3.5D eXtreme Dimension System-in-Package (XDSiP) technology. This marks the industry’s first 3.5D Face-to-Face (F2F) packaging platform, integrating over 6,000mm² of silicon and up to 12 HBM memory stacks within a single package. This innovation addresses the high-efficiency and low-power computing demands of AI chips.

The rapid growth of generative AI models has spurred the need for massive computational clusters composed of tens or hundreds of thousands of XPUs. These accelerators require increasingly complex integration of compute, memory, and I/O capabilities to deliver performance while minimizing power consumption and costs. Traditional scaling methods, such as Moore’s Law, are no longer sufficient. Advanced system-in-package (SiP) integration has become essential for next-generation XPUs.

Broadcom's 3.5D platform combines the advantages of 2.5D and 3D stacking technologies. By utilizing F2F direct metal layer connections, the platform ensures high-density, reliable interconnections with minimal electrical interference and robust mechanical strength. This approach allows chip designers to select optimal manufacturing processes for individual components, significantly reducing package size while improving performance, efficiency, and cost-effectiveness.

Broadcom is currently developing over five 3.5D products. Most of its AI customers have adopted the 3.5D XDSiP platform, with mass production slated to begin in early 2026.


The Rise of Advanced Semiconductor Packaging

The surge in AI applications has accelerated the adoption of advanced packaging technologies. Beyond Broadcom, major players like TSMC, Samsung, ASE (Advanced Semiconductor Engineering), and Intel are also driving innovation in this field.

TSMC’s 3D Fabric Ecosystem

TSMC’s Chip-on-Wafer-on-Substrate (CoWoS) technology is highly sought after, complemented by the SoIC (System-on-Integrated-Chips) process, part of its 3D Fabric system. This comprehensive solution integrates 3D stacking (SoIC), 2.5D advanced packaging (CoWoS), and InFO (Integrated Fan-Out) technologies. TSMC has been ramping up its SoIC production capacity, planning a 20-fold expansion by 2026. The company is also developing a dedicated "Advanced Packaging Zone" in Taiwan to support its future CoWoS and SoIC production lines.

Samsung’s 3.3D Packaging

Samsung is advancing its 3.3D packaging technology, designed for AI semiconductor chips. By replacing costly silicon interposers with transparent materials, the company has achieved a 22% reduction in production costs without compromising performance. Samsung also plans to implement panel-level packaging (PLP) to further improve efficiency and output.

ASE’s Chiplet Innovations

In March, ASE introduced Chiplet interconnect technology to address the diverse needs of AI-driven chip designs. By leveraging microbump technology and novel metal layers, ASE aims to reduce interconnect spacing significantly, opening applications for AI chips, mobile processors, and MCUs.

Intel’s Foveros Technology

Intel has begun mass production of its 3D Foveros packaging technology in New Mexico. This advanced solution combines lateral and vertical interconnectivity, optimizing latency and bandwidth by stacking memory directly atop active components. The modular design enables customization and faster time-to-market, offering a competitive edge in the advanced packaging arena.


Looking Ahead: Advanced Packaging in the AI Era

Advanced packaging technologies like Broadcom's 3.5D XDSiP and TSMC’s SoIC are transforming the semiconductor industry, enabling the integration of high-performance components to meet AI’s ever-growing demands. With more innovations on the horizon, advanced packaging is poised to become the cornerstone of the next generation of computing.

Related Articles