ABF substrate supply is fully booked through 2026 across all six global suppliers, prompting some second-tier makers to auction off available capacity via competitive bidding. Higher layer counts and larger body sizes for new GPU and ASIC platforms are increasing the production line time required per unit, while some customers are now seeking capacity commitments stretching beyond 2029.
T-glass and substrate-level CCL remain the primary constraints for 2027 shipments, affecting hardware from Nvidia and Google. Chinese vendors are entering the T-glass market to increase the number of sources from one to more than five. EMC plans to start shipping its own substrate CCL in 4Q26 and intends to double that capacity in 2027 to reduce the industry's reliance on Resonac.
Key sources
- SOURCE@semianalysis_“some of the second-tier suppliers have begun auctioning off their available capacity via competitive bidding”x.com
- SUPPORT@semianalysis_“TSMC underscored the impact of T-glass on CoWoS yield and reliability”x.com
- SUPPORT@zephyr_z9“Nvidia or Google can reduce HBM per GPU and DRAM per server to increase shipments, but they can't work around this”x.com