GoKawiilAt the North American Technology Symposium 2026, TSMC revealed its updated CoWoS packaging roadmap with major enhancements. Within chipmaking, the reticle limit is the largest size that a chip can be printed within a single step of the manufacturing process. TSMC's previous CoWoS-based system-in-packages (SiPs) roadmaps topped out at a 9.5-reticle size.
Now the company expects to produce 14-reticle and over 14-reticle-sized System-in-Packages (SiPs) with up to 24 HBM5E stacks by 2029. Such high integration is designed to meet the insatiable demand that AI accelerators have for both compute and memory bandwidth, and signals that packaging, not lithography, acts as a primary driver for semiconductor technologies.
"AI compute scaling is driven by the combination of advanced logic, SoIC 3D stacking, and CoWoS technologies," a statement by TSMC reads.
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Bigger, hotter and hungrier
TSMC's new roadmap lays out a plan for over 14 reticle size CoWoS SiP's by 2029. (Image credit: TSMC)
It is common for contemporary process technologies to scale slowly in transistor density, while full-node scaling enables 15% to 20% higher transistor density every three years. Intra-node improvements yield diminishing returns in density, but continue to provide performance improvements and greater power efficiency. This may not be a big problem for consumer product-makers, but it greatly affects the developers of AI and HPC applications, who must improve their solutions every year or two to remain competitive.
For those customers, TSMC has begun mass production of 5.5-reticle-sized CoWoS SiPs, supporting up to 12 HBM3E/HBM4 stacks and has achieved yields over 98%, according to the company.
In 2027, TSMC's CoWoS roadmap outlines a 9.5-reticle-sized interposer that supports 12 HBM5 stacks, which is expected to require a 120 mm by 150 mm substrate. In 2028, the company expects to produce a 14-reticle-sized interposer capable of carrying 20 3D-stacked compute chiplets and 20 HBM5 modules. By 2029, TSMC expects to produce interposers over 14 reticle sizes, with up to 24 HBM5E stacks. One standard reticle measures 26 mm by 33 mm (858 mm2), so a 14-reticle-sized interposer measures 12,020 mm2, or the size of a small plate, and slightly larger than a CD.
An SiP that uses a 14-reticle-sized interposer and measures 12,020 mm2 will consume an enormous amount of power, will require an exotic cooling solution (think exotic cold plates like those developed by Frore Systems, immersion cooling, or a combination of both), and will require a massive substrate, which will occupy a significant share of a server motherboard's real estate. The dimensions of the SiP alone will redefine how AI servers are built, whereas power consumption and cooling requirements are poised to open doors to a host of new technologies.
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