Advanced semiconductor packaging has become a central technology platform for high performance computing. For AI and HPC processors, performance depends not only on transistor density, but also on memory bandwidth, I/O density, power delivery, thermal management, and the ability to integrate more functional dies within a single package.
This is driving the continued adoption of 2.5D and 3D packaging architectures. In 2.5D packaging, chiplets are integrated side by side on an interposer/redistribution platform. In 3D packaging, active dies are stacked vertically using technologies such as hybrid bonding. Together, these approaches enable heterogeneous integration across different chiplets, bring memory closer to compute, increase die-to-die interconnect density, shorten electrical paths, and support the integration of optical and electrical components within the same package.
This article explores the technology development trends in advanced semiconductor packaging technologies. The insights are derived from IDTechEx’s recent report, “Advanced Semiconductor Packaging 2027-2037: Forecasts, Technologies, Applications,” which delves deep into understanding the technical aspects of packaging technologies, examining industry challenges, the progress made by leading companies, and providing market forecasts for the sector.
Evolution Roadmap of Semiconductor Packaging. Source: IDTechEx
Key trends in 2.5D and 3D packaging development to watch
- Larger package areas
One of the clearest trends in advanced semiconductor packaging is the continued increase in package size. AI and HPC systems require more compute dies, I/O dies, and HBM stacks to be integrated within a single package to improve system-level performance. As a result, the industry is moving toward interposer and substrate platforms that can scale package area while maintaining high interconnect density.
TSMC’s CoWoS roadmap illustrates this direction. In 2026, TSMC is already in volume production of a larger 5.5× reticle-scale CoWoS_L platform (Si bridge platform), targeting large multi-die architectures with high-end compute tiles, multiple I/O dies, and up to around 12 HBM3E/HBM4 stacks. By 2027, further scaling toward approximately 9.5× reticle-scale packages is expected to enable even larger compute and memory configurations.
This scaling trend is also changing the interposer technologies being adopted. Full silicon interposers have supported the current generation of high-performance AI accelerators, but their scalability is constrained beyond around 3.3× reticle size due to yield, cost, and manufacturability challenges. As a result, bridge-based architectures and glass-based platforms are gaining attention as the industry seeks to extend 2.5D integration without relying on full-area silicon interposers.
- Panel-level packaging
Panel-level packaging is being explored as a route to larger and more cost-effective advanced packages. By moving from circular wafers to rectangular panels, manufacturers can improve area utilization and therefore enable higher throughput and reducing packaging cost per AI accelerator.
However, the transition remains technically challenging. As panel sizes scale from early development formats around 310 × 310 mm toward larger formats such as 510 × 515 mm or 620 × 750 mm, manufacturing becomes more difficult.
Key challenges include warpage control, finer RDL formation, yield management, standardization, thermal management, full panel uniformity, and so on. These factors directly affect yield, interconnect reliability, and the ability to manufacture fine-pitch redistribution structures at scale. Commercial adoption will therefore depend on whether the industry can convert large-area processing advantages into stable, high-yield manufacturing.
- Glass interposers and glass core substrates
Glass is emerging as a key materials platform for next-generation advanced semiconductor packaging, driven by the limitations of both organic substrates and silicon-based interposers. Organic substrates are well established and cost-effective, but face challenges especially in fine-line routing and warpage as package size increases. Silicon-based interposers offer high interconnect density, but their scalability is constrained by reticle limits, wafer utilization, and cost, particularly as AI accelerator packages continue to grow.
Glass offers a potential middle ground. It can support fine routing, provides material advantages such as tunable coefficient of thermal expansion, and is compatible with large-area panel processing. However, glass-based packaging remains at an early stage of commercialization. The key questions are not only whether glass can deliver attractive electrical and mechanical properties, but whether manufacturing processes can scale reliably, and whether the broader ecosystem is ready to support high-volume adoption.
On the manufacturing side, challenges remain in through-glass via formation, metallization, large-panel handling, inspection, warpage control, reliability qualification, and cost-effective production. On the ecosystem side, wider adoption will depend on the readiness of material suppliers, equipment vendors, substrate manufacturers, foundries, OSATs, and design-tool providers to support glass-based packaging at commercial scale.
- Hybrid bonding
Compared with conventional microbump-based interconnects, copper-copper hybrid bonding enables finer interconnect pitch, lower parasitic resistance and capacitance, and higher vertical interconnect density between stacked dies.
The technology is already used in several high-end products. Examples include AMD’s 3D V-Cache, which stacks SRAM on CPU dies in its EPYC data center processors, and the MI300 series, which also uses hybrid bonding technology to stack CPU/GPU tiles on I/O dies. Intel is also adopting its own 3D hybrid bonding technologies for next-generation server CPUs.
Beyond logic stacking, hybrid bonding is expected to become increasingly important for memory. As HBM moves beyond 16-Hi and 20-Hi stacks, conventional stacking and bonding approaches will face growing challenges in interconnect density, stack height, and thermal performance. Hybrid bonding is therefore being expected as a key route for future high-density DRAM stacking.
Hybrid bonding also plays a key role beyond processor and memory integration. In co-packaged optics, it can be used to integrate electronic ICs with photonic ICs. This makes hybrid bonding a cross-cutting technology across computing, memory, and optical interconnects.
- Co-packaged optics
Co-packaged optics is emerging as an important advanced semiconductor packaging opportunity as data centers require higher bandwidth and greater power efficiency. In conventional pluggable optics, the optical engine is located at the front panel and connected to the switch ASIC through long Cu traces on PCB. As switch bandwidth increases, these electrical paths become increasingly constrained by signal loss, power consumption, connector density, and thermal limits. Similar optical I/O concepts are also being explored for accelerator systems, where optical engines could be integrated closer to GPUs or other compute dies.
In first-generation CPO architectures, 2.5D packaging can integrate optical engines on the same package substrate as the main compute or switching die, reducing electrical path lengths from tens of centimeters to a few millimeters. Next-generation CPO architectures may further shorten interconnects by packaging optical engines together with the compute die on an interposer.
Advanced semiconductor packaging therefore plays a central role in CPO by enabling dense electrical routing, shorter die-to-optical-engine connections, and integration of EICs, PICs, interposers, redistribution layers, and fiber-attach structures. However, the packaging challenge also increases. Optical alignment, fiber-to-chip coupling loss, thermal management, testability, repairability, assembly yield, and long-term reliability remain key barriers to scalable adoption.
In summary, advanced semiconductor packaging is becoming a critical enabler for AI and HPC systems, as performance increasingly depends on system-level integration rather than chip performance alone. The continued development of 2.5D and 3D advanced packaging technologies will be essential for improving bandwidth and power efficiency at the system level, while also creating new technical challenges across manufacturing, thermal management, optical coupling, and supply chain readiness, especially for emerging material platforms. To learn more about these technology trends and market opportunities, please refer to IDTechEx’s report, “Advanced Semiconductor Packaging 2027-2037: Forecasts, Technologies, Applications.”
