Chinese foundries are prevented from buying extreme ultraviolet lithography machines (EUV) thanks to the U.S. sanctions. The largest foundry in China, SMIC, is limited to using DUV machines (deep ultraviolet lithography) which it was allowed to buy before the U.S. crackdown and certain models can still be shipped to the company today. The only problem is that using DUV instead of EUV limits SMIC to producing 7nm chips which are two process node generations behind the 3nm chips currently produced by TSMC and Samsung Foundry.
Chip expert says that Huawei might be able to obtain 5nm Kirin chips although it will be expensive to produce