The measures are set to undermine China's efforts to develop its own chip industry aimed at reducing its reliance on foreign-made chips.
These are the questions," says Marco Mezger, a consultant in Taiwan who tracks the global memory chip sector.
Washington is also scrambling to tackle unintended consequences of its new export curbs, people familiar with the matter said.
Hours before the new restriction took effect, South Korea's SK Hynix (000660.KS) said it got U.S. authorization to receive goods for its chip production facilities in China without additional licensing imposed by the new rules.
Yet business at toolmaking firms servicing Chinese customers has already slowed dramatically, leaving their staff with little work to do but creating an opening for Chinese equipment makers seeking to catch up with western rivals, sources said.