Ibiden says AI-server substrate demand grows 5.4 times by 2030, and its shares fell 15% anyway

Ibiden▼−15.21% — Ibiden, down 15.21 percent today (Tokyo: 4062), the Japanese maker of the boards AI accelerators sit on, said on October 30, 2026, that demand for AI-server substrates will grow 5.4 times by 2030 and that total demand will significantly exceed what the industry can supply ¹². Ibiden had just raised its full-year profit forecast on AI-server orders, and its shares still fell 15%, enough to hit the Tokyo exchange's daily price limit ¹.

The open question is no longer whether the substrate shortage is real; it is who can finance a share of it, and the next answer comes from AT&S (Vienna: ATS) on November 5 ³.

Bigger boards are driving the shortage

AI accelerators are assembled as chiplets on packages that keep growing, so each accelerator consumes more board. Ibiden's presentation↗ shows substrate sizes rising from 80 by 80 millimetres to 130 by 130 by 2030, with layer counts rising in step ¹. Most of the extra demand comes from each board getting bigger and denser rather than from more chips.

Nvidia's counter, signed at GTC Berlin on October 21↗ with Ibiden, Samsung Electro-Mechanics and Unimicron, lifts contracted substrate supply about 2.5 times over three years; the list, which we reported on October 24, does not include AT&S ⁵⁶. Ibiden is adding about ¥150 billion of plant at Gama, but mass production there starts in fiscal 2029, and capacity of this kind takes two to three years from money to qualified output ¹⁵. One of the two plans is wrong, and everything built on substrates inherits the difference.

The risk at AT&S is cash, not demand

AT&S expanded its Kulim plant in Malaysia in June on agreements with AMD and one other unnamed technology company↗, a €1.5 to 2.0 billion project it says is fully financed by long-term customer commitments ⁷. It lifted its revenue-growth forecast to 45 to 55% at the same time ⁷.

The balance sheet is thinner than the order book: customer prepayments stood at €907 million at June 30↗ ⁸, and the June quarter produced €39.9 million of operating cash flow↗, a fraction of the company's debt ⁹. A stock trading far below the €242 high it set this year ⁴ is being priced on its balance sheet, not on its orders.

The AI line nobody models

AT&S also disclosed on October 21 that Infineon, the German power-chip maker, had given it a Best Value Creation award↗ for embedding technology in power modules for AI servers, after more than ten years of cooperation ³⁴. No revenue is attached. But Infineon is investing €1.1 billion through 2034 in power chips for AI data centers at Villach and has begun shipping rack power-delivery products ¹¹, and embedded modules are how that silicon reaches a rack. It is the AI business at AT&S that sits outside every earnings model.

Two cash lines decide the discount

Two lines in the November 5 half-year report decide the discount: customer prepayments holding above their June 30 level, and operating cash flow stepping up from the June quarter and staying there ⁸⁹.

While the prepayments keep coming, AT&S owns a scarce substrate business. If they stop, it owns a fab it cannot fill.

Above both lines, AT&S is the cheapest listed exposure to a shortage Ibiden dates to 2030, against a €308 consensus target↗ ¹⁰. Below them, the 45% discount to the peak is the right price ¹⁰. The shortage runs for years; the constraint has moved to the balance sheet, and the reward now sits with whoever can carry it.