[Edaily Reporter JAEMIN SONG ] Bottlenecks in the artificial intelligence (AI) semiconductor supply chain are spreading from wafers and high-bandwidth memory (HBM) to insulating films for packaging substrates. This is because as AI chips become increasingly larger and more complex, the amount of insulating film required per substrate is rising, while production lines for these key materials are already operating at full capacity.

According to industry sources on the 26th, Japan’s Ajinomoto has recently decided to prioritize limited supplies of ABF (Ajinomoto Build-up Film) for AI and high-specification products due to a shortage of the material. Since Ajinomoto effectively monopolizes the global ABF market for high-performance semiconductors, any change in supply allocation directly impacts the production of substrate manufacturers. Ajinomoto’s ABF production lines are reportedly operating at virtually full capacity as of the second quarter of this year.

ABF is an insulating film for semiconductor package substrates developed by Ajinomoto. Substrate manufacturers stack multiple layers of this film and fine wiring layers to create “FC-BGA (Flip Chip Ball Grid Array),” a high-performance substrate that connects GPUs, CPUs, and server motherboards. With NVIDIA having begun full-scale mass production of its next-generation AI platform, “Vera Rubin,” in May, demand for high-specification ABF substrates is expected to increase further.

The issue is that as AI chips grow larger, the number of boards that can be produced from a single manufacturing panel decreases sharply. According to Meritz Securities, a single 515×515 mm panel can yield 270 boards with an area of 830 mm², but when the board area increases to 10,000 mm², production drops to just 20 boards.

The substrate area of next-generation AI chips, such as NVIDIA’s “Feynman” scheduled for release in 2028, is expected to be 3 to 5 times larger than that of products released in 2026. Analysts suggest that even if AI server shipments fall short of market expectations, the total demand for substrates could continue to rise due to the significant increase in the substrate area required per chip.

On the other hand, expanding the supply of ABF—which directly impacts substrate production—will take considerable time. Ajinomoto is moving forward with the construction of its third ABF production plant in Gifu Prefecture, Japan, following facilities in Kawasaki and Gunma, but construction is scheduled to begin in 2028, with operations set to start in 2032. This is why the supply of high-specification ABF and the packaged substrates that utilize it is likely to remain tight for the time being.

In South Korea, SamsungElectroMechanics is producing high-specification FC-BGA using ABF at its Busan facility and its factory in Vietnam. SamsungElectroMechanics plans to invest an additional approximately $1.2 billion (1.8 trillion won) in its Vietnamese subsidiary to expand FC-BGA production capacity. Beyond expanding production facilities, securing a stable supply of ABF and improving the yield rate for large-area substrates are expected to be key factors in actually increasing supply.

An industry official stated, “As AI chips grow larger, both the substrate area and the number of wiring layers increase, so ABF usage is bound to rise as well,” adding, “If raw material prices rise due to supply shortages, the extent to which companies can pass these costs on to substrate prices will determine their profitability.”