China has started mass production of domestically developed immersion deep-ultraviolet (DUV) lithography machines, a key technology used in semiconductor manufacturing, according to a source cited by Reuters. Immersion DUV lithography uses a layer of water between the projection lens and the silicon wafer, allowing manufacturers to print smaller circuit patterns than conventional dry systems. News outlet The Information first reported that Shanghai-based Aishengna had begun manufacturing the DUV machines, with plans to produce about five units this year and around 20 in 2027. Its DUV machines are not yet comparable to those made by Dutch supplier ASML and require further testing. China has been barred from purchasing ASML’s most advanced extreme ultraviolet (EUV) lithography systems under U.S. restrictions, while Dutch export controls have also limited access to some advanced DUV machines.