AI server architectures are rapidly shifting toward ultra-high-density designs, keeping advanced CoWoS packaging capacity persistently tight. The primary bottleneck stems from continuously expanding chip sizes, which introduce warpage and thermal stress challenges while driving ABF substrate demand to multiply, creating structural supply pressure and underpinning a recovery in 2025 operations for Taiwan's three leading IC substrate makers.

As AI chip package sizes continue to grow, warpage issues in IC substrates have become more pronounced. Capacity constraints for low-CTE fiberglass cloth, a critical material used to address warpage, are forcing end customers, including Apple, Nvidia, Google, and AWS, into increasingly intense competition for supply, industry sources said.