This is a big deal in the lithography world. Photoresist platforms, and the developer materials that go with them, almost never change. In the entire history of semiconductor lithography, it has happened once: the shift from Novolac/DNQ resists (broadband and i-line) to chemically amplified resists (CAR). CAR then carried every subsequent scanner generation: i-line, KrF, ArF, and EUV. These are essentially acrylic polymers plus a photoacid generator and a basic quencher. The prevailing assumption was that high-NA EUV would break that streak. CAR would not work; a new platform, metal oxide resist (MOR), would be required. High-NA scanner data comparing the two appeared to support that view. In my opinion, that comparison was never apples-to-apples. CAR is built on a long polymer chain with a defined molecular weight. MOR uses a much smaller metal-oxide molecule, a fraction of CAR’s MW. Across the generations CAR has spanned, which is all of them, that molecular weight was never static. As printed geometries shrank, polymer chain length was reduced accordingly. Most CAR-vs-MOR comparisons did not use a resist optimized for the new high-NA pattern sizes. imec, working with materials suppliers, did. With a newly optimized CAR, the data shows that chemically amplified resists can work. Why this matters: changing photoresist platforms is a major undertaking. MOR in particular brings serious high-volume challenges, metal contamination of the tool set, and the fact that it only works in negative tone. CAR is 100% organic, already established in production, and most importantly operates in positive tone, with a negative-tone option available as well. If an optimized CAR can perform anywhere near MOR, it will be the preferred material of choice. Bad news for JSR and LAM who have made big investments in the metal oxide materials and dep/etch tooling.