South Korea has charged a former Samsung executive accused of stealing company secrets worth hundreds of millions of dollars to set up a copycat chip factory in China, prosecutors told AFP on Tuesday.

Semiconductors have become a flashpoint issue between the United States and China, which are locked in a fierce battle over access to chip-making technology and supplies.

South Korean prosecutors said the 65-year-old former Samsung employee allegedly stole the company's factory blueprints and clean-room designs from 2018 and 2019.

The Suwon district prosecutor's office said the suspect unsuccessfully tried to set up a copycat production facility in the Chinese city of Xian — where Samsung already has a chip factory.

The man, who has not been identified and is in detention pending trial, stole material that is classified by South Korea as a "national core technology" -- a category of tech that could potentially harm national security and the economy if disclosed overseas.

Prosecutors said he had been in custody for some time and was formally charged on Monday.

They described him as a "top expert in semiconductor manufacturing", who had worked in the industry for decades.

South Korean authorities said the information allegedly targeted in the theft would have been worth at least $236 million to Samsung.

"It is a serious crime that can have a tremendous negative impact on our economic security by shaking the foundation of the domestic semiconductor industry at a time when competition for chip production is intensifying every day," prosecutors said in a statement on Monday.

"The semiconductor industry accounted for 16.5% of South Korea's total exports in 2022... and is a national security asset."

Six other people who worked with the executive have been charged over suspected involvement in the theft.

Samsung declined to comment when contacted by AFP on Tuesday.

Chip war

Samsung Electronics is one of the world's largest producers of chips and smartphones, and its parent group's turnover is equivalent to about one-fifth of South Korea's GDP.

Like many of the world's biggest chip makers, a large portion of its production is based in China.

Chips are the lifeblood of the modern global economy, and China — the world's second-largest economy — relies on a steady supply of chips made by foreign firms for its huge electronics manufacturing industry.

The United States imposed a series of export controls last year to prevent China from acquiring the most advanced chips that could be used in cutting-edge weapons and frontier tech such as artificial intelligence.

The Netherlands and Japan followed this year with restrictions of their own, without naming China.

But the curbs have infuriated Beijing, which has accused Washington of "technological terrorism."

China last month said U.S. chip giant Micron had failed a national security review, and told operators of "critical information infrastructure" to stop buying its products.

Analysts have described that move as retaliation for the U.S. semiconductor curbs.

"Amid intensifying semiconductor competition between the U.S. and China, South Korea is in a difficult situation as it has to side with its security ally U.S. while it obviously cannot ignore Beijing and its influence," Kim Dae-jong, a professor of business administration at Sejong University, told AFP.

"Samsung Electronics should pay more attention to technology and information security. China is trying to catch up."