TrendForce reported in June 2026 that the gap between supply and demand for TSMC's CoWoS advanced packaging is expected to narrow from around 20% to roughly 10% by the end of the year, as TSMC and its partners continue expanding capacity aggressively.

TSMC also disclosed in May 2026 that yield on its 5.5-reticle CoWoS packaging technology has exceeded 98%, alongside plans to bring five new fabs online during the year as part of a broader push to relieve the bottleneck.

Why it matters

CoWoS, TSMC's chip-on-wafer-on-substrate packaging process, is what allows GPU compute dies to be physically bonded next to HBM stacks on the same package, and it has effectively been the binding constraint on how many AI accelerators companies like Nvidia can ship, not raw wafer manufacturing capacity. A June 2026 industry analysis estimated total 2026 CoWoS demand near 1 million wafers, up from about 370,000 in 2024, with lines described as fully booked.

Because CoWoS capacity, rather than logic wafer starts, has been the limiting factor, its expansion pace directly determines how fast AI GPU shipments can grow even when the underlying chips are ready.

How it works

CoWoS packages a logic die and its HBM stacks onto a silicon interposer, then mounts that interposer onto a substrate, allowing very high-bandwidth, short-distance connections between compute and memory that a standard printed circuit board cannot support at the same density. TSMC uses two variants, CoWoS-S and CoWoS-L, both of which are described as fully allocated through 2026.

Mizuho's analysis, cited by Investing.com, lifted its TSMC CoWoS capacity forecasts this year, citing surging demand from server CPU makers in addition to GPU customers, indicating that packaging demand is broadening beyond just Nvidia and AMD's AI accelerators.

The competing read

Some outlets frame the narrowing supply-demand gap as evidence the crunch is ending, but Digitimes' September 14 analysis argued that even as High-NA EUV and packaging technologies mature, economics rather than technical readiness will pace how quickly capacity actually converts into shipped product, since new packaging lines require significant capital and lead time to qualify.

Separately, a report from Futu News on TSMC's revised advanced-packaging roadmap said the company's next-generation CoPoS technology, seen as CoWoS's eventual successor, is not expected until the fourth quarter of 2030 at the earliest, an extended lifecycle for CoWoS that some read as reassuring supply stability and others read as a sign TSMC is struggling to bring a replacement to market faster.

What happens next

TrendForce's own estimate points to the CoWoS supply gap narrowing to roughly 10% by the end of 2026, which would still leave meaningful undersupply heading into 2027 even after this year's capacity additions.

With CoPoS not expected until 2030, TSMC's near-term strategy is to keep extending the CoWoS platform's capacity and yield, so further disclosures on new packaging fab openings and yield milestones are likely at TSMC's remaining 2026 and 2027 earnings calls.