GoKawiilABF substrates, the specialized insulating and wiring bases that connect tiny silicon chips above them to the much larger printed circuit boards below, sit beneath most high-end CPUs, GPUs, and AI accelerators. Featuring the Ajinomoto build-up film (ABF), these substrates have been critical to the semiconductor industry since the late 1990s, with personal computers, workstations, servers, and networking silicon driving steady demand for decades.
The artificial intelligence boom has multiplied that demand exponentially. Training and inference for frontier models now run across data centers, each housing hundreds of thousands of accelerators and providing hundreds of megawatts of compute. Nvidia alone shipped an estimated 3.2 million Blackwell GPU packages through the end of 2025, with every one of those accelerators packaged on an ABF substrate. Meanwhile, the industry is already entering the gigawatt era with humongous data center buildouts, each expected to house millions of AI accelerators.
This edifice rests on a remarkably narrow supply chain. Practically every advanced logic and AI chip made today by Intel, AMD, and Nvidia depends fundamentally on ABF substrates. These substrates are the conventional default for high-performance packaging. They are made by a small group of specialists, including Unimicron, Ibiden, Kinsus, Shinko Electric Industries, Samsung Electromechanics, and Nan Ya PCB. The upstream supply chain gets much tighter.
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The one common denominator across ABF substrates, regardless of manufacturer, is the Ajinomoto build-up film itself. Each substrate maker laminates its build-up layers using dielectric film supplied by Japan's Ajinomoto, which controls a reported 95% or more of the global market. A single company, better known for food seasoning than microelectronics, sits at the base of one of the most concentrated supply chains in computing, almost singlehandedly supplying a material for hundreds of millions of semiconductor devices. Not surprisingly, demand is now growing beyond what the supply chain can comfortably supply.
Compounding this crunch, modern AI accelerators now pack multiple compute, memory, and supporting components onto a single board. As a result, the substrate is getting larger across the X-Y footprint to accommodate the expanding package. Manufacturers are also adding more build-up layers to the substrate to route the growing number of signals and power connections. Each additional layer requires another ABF layer, further multiplying demand across millions of accelerators and extending manufacturing times.
Unfortunately, the complications don't stop there. Beyond further straining the supply chain, expanding the substrates is creating technical problems, such as warpage, yield issues, and electrical losses within the component itself. This leaves the ABF substrate ecosystem facing two related challenges: producing enough advanced substrates for a rapidly expanding fleet of AI accelerators, while simultaneously re-engineering these substrates so they can continue to scale without becoming unmanufacturable or impractical.
The ABF substrate roadmap is consequently as much about supply-chain capacity as it is about the hardware itself, with suppliers such as Ajinomoto and Ibiden outlining plans to expand material and manufacturing capacity, respectively. At the same time, the wider industry — Intel, Samsung, and SK's Absolics among them — is exploring glass-core substrates and other material technologies to push past the limits of organic ABF.
ABF substrates
Silicon dies, including CPUs and GPUs, cannot communicate directly with the printed circuit board beneath them. The connection pads on a die are spaced micrometers apart, while the traces on a motherboard are spaced hundreds of micrometers to millimeters apart. Every high-performance chip, therefore, sits on an intermediary package substrate — a dense, multilayer board that fans the ultra-fine connections on the die outward into connections large enough for the motherboard to handle, while also providing signal routing, power and ground distribution, and mechanical support for the package.
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