Globally critical chip firm tells U.S. staff to stop servicing China customers after Biden export curbs

ASML, one of the world’s most important semiconductor toolmakers, told U.S. employees to stop servicing Chinese customers, as Washington’s latest export restrictions begin to hit the global chip industry.

The Dutch firm said in a memo that any U.S. staff, including American citizens, green card holders and foreign nationals living in the U.S., “are prohibited from providing certain services to advanced fabs in China.”

ASML’s U.S. employees “must refrain — either directly or indirectly — from servicing, shipping, or providing support for any customers in China until further notice, while...