Photo/Illutration A factory of Taiwan Semiconductor Manufacturing Co. (TSMC) in Tainan, Taiwan (Asahi Shimbun file photo)

TAIPEI--Taiwanese chipmaker TSMC is planning to produce chips with advanced 3-nanometre technology at its new factory in the U.S. state of Arizona but the plans are not completely finalized yet, the company’s founder Morris Chang said on Monday.

Taiwan Semiconductor Manufacturing Co. Ltd. (TSMC), a major Apple Inc supplier and the world’s largest contract chipmaker, is constructing a $12 billion plant in Arizona.

Last year, Reuters reported TSMC’s plans to build more chipmaking factories in Arizona, including discussions about whether its next plant should be more advanced which could make chips with 3-nanometer technology compared to the slower, less-efficient 5-nanometer chips that will be churned out when the facility begins production.

Chang, speaking to reporters in Taipei after returning from the APEC summit in Thailand, said the 3-nanometre plant would be located at the same Arizona site as the 5-nanometre plant.

“Three-nanometer, TSMC right now has a plan, but it has not been completely finalized,” said Chang, who has retired from TSMC but remains influential in the company and the broader chip industry.

“It has almost been finalized--in the same Arizona site, phase two. Five-nanometer is phase one, 3-nanometre is phase two.”

TSMC, Asia’s most valuable listed company, declined to comment.

The company is holding a “tool-in” ceremony in Arizona on Dec. 6.

Chang said he would be attending, along with TSMC customers and suppliers and U.S. Commerce Secretary Gina Raimondo.

Chang added that U.S. President Joe Biden has also been invited, but that he didn’t know if he would be going.