Demand for AI infrastructure continues to expand, placing a new round of upstream bottlenecks on the high-end PCB supply chain. Following T-glass fabric, HVLP4 copper foil is emerging as the most critical supply constraint for the second half of 2026, with the market anticipating a shortfall of 1,500 tonnes this year, widening further to 2,500 tonnes by 2027.

According to industry sources cited by Digitimes Asia, NVIDIA and its major clients are once again directly intervening in upstream material supply coordination to ensure the mass production and shipment schedules for next-generation AI servers remain on track.

NVIDIA is providing clearer order visibility to glass fabric and copper foil suppliers and is advancing a direct consignment model, locking in key upstream capacity more than a year in advance.

This development signals that the AI supply chain contest has extended from the chip and substrate level to the more upstream raw materials sector. The customer base led by NVIDIA is bypassing copper-clad laminate (CCL) manufacturers to engage directly with glass fabric and copper foil suppliers, attempting to resolve bottlenecks before material shortages escalate into a crisis for end-product shipments.

Escalating HVLP4 Copper Foil Shortage

As mainstream AI servers and high-speed computing platforms rapidly transition from HVLP2 and HVLP3 to HVLP4, demand for the corresponding copper foil is surging. According to market sources cited by Digitimes, the supply-demand gap for HVLP4 copper foil is projected to reach 1,500 tonnes in 2026.

Although Mitsui Kinzoku and Taiwan's Co-Tech Development are actively expanding production, constrained by the high technical barriers and difficulty in scaling capacity for ultra-low profile copper foil, supply growth is still struggling to keep pace with AI demand. The shortfall is expected to widen further to 2,500 tonnes by 2027.

HVLP4 copper foil, a type of ultra-low profile copper foil, is a critical material supporting high-frequency, high-speed signal transmission. As demand for high-end CCL evolves from M6 to M7, M8, and even M9 specifications, the requirements for copper foil quality are rising concurrently, while the number of suppliers with mass-production capabilities remains extremely limited.

NVIDIA Bypasses CCL Makers for Direct Control

Glass fabric and copper foil suppliers have long occupied the "upstream of the upstream" in the PCB supply chain, with material development and production planning historically led by CCL manufacturers such as Elite Material and South Korea's Doosan Electro-Materials. End customers like Apple and NVIDIA have had difficulty directly accessing this tier.

However, as supply constraints at the IC substrate and PCB levels persist, the customer base led by NVIDIA is altering this dynamic by establishing direct connections with upstream material suppliers, bringing glass fabric and copper foil under their own supply chain management. Industry sources also indicate that NVIDIA is applying greater procurement pressure to US cloud service providers, including Google, AWS, and Meta.

CCL suppliers have already implemented rare quota-based allocation measures, requiring IC substrate and PCB manufacturers to collect materials based on actual usage, further highlighting the scarcity of upstream materials.

T-Glass Fabric Also in Critical Short Supply

HVLP4 copper foil is not the only bottleneck. Supply of T-glass fabric used in IC substrates is also extremely tight. Japan's Nittobo controls over half of the global capacity, while yield issues at new entrants like Taiwan Glass are affecting delivery schedules, leading to an estimated supply-demand gap exceeding 40% in 2026.

According to Digitimes, even by 2027, the T-glass supply-demand gap is still projected to be as high as 25%, which will continue to constrain the capacity expansion of ABF substrates. In the high-end glass fabric sector, Low DK2 and T-glass are the primary items in short supply, already triggering active price increases within the supply chain.

For investors, the dual bottlenecks in upstream materials mean the tight situation in the AI server supply chain is unlikely to ease in the short term. The few suppliers with HVLP4 copper foil and T-glass fabric capacity will continue to benefit from the pricing leverage afforded by the supply-demand imbalance.