Damnang
· Damnang’s Substack
· June 14, 2026 at 06:01
· ⏱ 13 min read
| Read on Substack ↗
Summary
Glass substrate is not a single theme but four distinct applications (glass core, interposer, carrier, T-glass) with different timelines and beneficiaries. The article argues that timing is the crucial investing insight: T-glass (Nittobo) benefits now from organic substrate demand, while glass core substrates won't reach volume until 2027+, and TSMC's CoPoS pilot line completion within 2026 is the key event for glass carrier demand. Investors must distinguish between these to avoid mistaking the cycle and getting the timing wrong.
•Four distinct glass applications in packaging: glass core substrate, glass interposer, temporary carrier, and T-glass (glass fiber cloth) — each with different companies, timelines, and money flows.
•T-glass (Nittobo, ~90% market share) is currently in shortage and benefits organic substrate sales, while glass core substrate is a replacement technology that won't see volume until 2027 at earliest.
•TSMC's next-generation packaging CoPoS uses a 310x310mm glass carrier and is on schedule to finish the pilot line within 2026; a larger 510x515mm glass core substrate structure is floated for volume stage.
•Absolics is running AMD qualification for glass core substrates at its Georgia fab; Samsung Electro-Mechanics has shipped glass substrate samples to Apple.
•Glass substrates solve warpage (CTE match to silicon) and area limits (panel-level packaging) but face brittleness and TGV (through-glass via) drilling yield challenges.
•Money flows first to raw glass and equipment suppliers (1-2 years ahead of substrate makers), then to substrate makers after qualification passes — timing varies by a year or two even within the same glass substrate cycle.
Author details TSMC's next-generation panel packaging CoPoS using a glass carrier (310x310mm) and its schedule to finish the pilot line within 2026, citing Ming-Chi Kuo's industry check. Glass carrier
Author details TSMC's next-generation panel packaging CoPoS using a glass carrier (310x310mm) and its schedule to finish the pilot line within 2026, citing Ming-Chi Kuo's industry check. Glass carrier is the most certain near-term glass demand. TSMC is the central player in the panel-level packaging transition.
Risk: Glass core substrate adoption for CoPoS is not confirmed; if yield or qualification delays occur, carrier-only demand may be less than expected.
Author names Nittobo as holding ~90% of the T-glass market and describes it as a near-term bottleneck benefiting from rising organic substrate demand, with capacity expansion targeting 2027 operation
Author names Nittobo as holding ~90% of the T-glass market and describes it as a near-term bottleneck benefiting from rising organic substrate demand, with capacity expansion targeting 2027 operation and a next-generation T-glass launch in 2028. This is a separate, earlier cycle from glass core substrates.
Risk: T-glass demand is tied to organic substrate volumes; if glass core adoption accelerates, it could displace T-glass demand, but that is 2027+.
This newsletter, published June 14, 2026,
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