The extreme ultraviolet lithography machine (EUV), used to create circuitry patterns on silicon wafers, is possibly the most important chipmaking equipment banned in China. Used in the production of 7nm chips with the latest model helping foundries take their process nodes down to 2nm, China's leading foundry, SMIC, still relies on using older technology such as deep ultraviolet lithography (DUV). Some DUV machines, including immersion DUVs, are banned in China because they contain some parts built in the U.S. For years, there has been talk that China would get around the EUV ban by developing its own machine. Rumors that…