TSMC and ASML have launched a joint initiative to shift extreme ultraviolet photomasks from the established 6-inch format to 12-inch masks, a change intended to support volume manufacturing with next-generation High-NA EUV lithography. TSMC plans to build a 12-inch photomask pilot line by 2031 and achieve full lithography-system readiness by 2033, while targeting High-NA EUV deployment in advanced-process volume production from 2030. High-NA EUV systems, priced at about $380 million to $410 million each, offer higher-resolution patterning but require changes across the mask and inspection supply chain. Larger masks are designed to improve manufacturing efficiency, reduce costs and accommodate the growing number of advanced chip layers needed for increasingly complex AI-oriented designs. The announcement helped lift TSMC shares to an intraday NT$2,485, about 2% below their NT$2,535 record high. The development builds on a broader High-NA EUV transition involving TSMC, Samsung and ASML, with Samsung targeting use of the technology in DRAM production from 2028 before expanding it to advanced logic processes.