Broadcom has unveiled the groundbreaking 3.5D eXtreme Dimension System-in-Package (XDSiP) platform technology, marking a first in the industry. This pioneering 3.5D F2F packaging innovation integrates over 6,000mm² of silicon alongside up to 12 HBM memory stacks within a single package, specifically designed to cater to the high-efficiency and low-power computing demands of AI chips.

The 3.5D XDSiP represents a novel multi-dimensional stacked chip platform. It fuses 2.5D technology with 3D-IC integration, utilizing Face2Face (F2F) technology, and empowers consumer AI customers to develop next-generation tailor-made accelerators (XPUs) and compute ASICs. This platform delivers advanced, optimized System-in-Package (SiP) solutions to support large-scale AI applications.

According to Broadcom, the introduction of the 3.5D XDSiP heralds a new era in customized computing. The platform offers several key advantages:

• Enhanced Interconnect Density - Achieves a 7x increase in signal density between stacked dies compared to F2B technology.
• Superior Power Efficiency - Significantly reduces power consumption for Die-to-Die interfaces to one-tenth of the original by adopting 3D HCB instead of conventional planar Die-to-Die PHYs.
• Reduced Latency - Minimizes latency between compute, memory, and I/O components within the 3D stack.
• Compact Form Factor - Enables smaller adapter board and package sizes, leading to cost savings and improved package warpage.

The official presentation indicates that six 3.5D XDSiP products are currently in development, with shipments anticipated to commence as early as February 2026. These developments include Fujitsu's forthcoming Arm processor for AI (artificial intelligence) and HPC (high-performance computing) applications, codenamed "MONAKA," which is set to succeed the existing A64FX.