Seoul appeals court cuts ex-Samsung employee's sentence to 5 years for leaking DRAM secrets to China's CXMT

The Seoul High Court on Oct. 22 cut the prison sentence of a former Samsung Electronics employee from seven years to five. He was convicted of leaking the company's classified 18-nanometer DRAM technology to Chinese chipmaker ChangXin Memory Technologies, known as CXMT.

The defendant, identified as Jeon, spent nearly three decades at Samsung before joining CXMT in 2016. The first-trial sentence came in April.

What was taken

The core of the case is a document called the Process Recipe Plan. According to prosecutors, it covers roughly 600 manufacturing steps for Samsung's 18-nanometer-class DRAM. Samsung reportedly spent more than 1 trillion won and five years developing the process.

The appellate court found the technology used at CXMT traced back to a Samsung process architecture engineer surnamed Park. In September 2016, Park allegedly copied the process specifications by hand onto 12 pages of notes and carried them out of the company. Park is the subject of an Interpol Red Notice.

At CXMT, Jeon oversaw equipment investment. The court found he compiled equipment investment information for the so-called Hefei Project.

The money

Investigators found Jeon received about 2.9 billion won from CXMT over six years. That figure includes contractual incentives and stock options. Depending on the conversion used, it works out to roughly $2 million to $2.2 million.

Why the court cut the sentence

The judges did not soften their language. "The defendant's actions warrant severe condemnation, as the leak of Samsung Electronics' nationally critical technology posed a serious threat to Korea's industrial competitiveness," the court said.

But the court also said the seven-year term "was excessive in some respects." It cited two reasons. Jeon was not directly involved in semiconductor development at CXMT. And his testimony in a separate CXMT technology-theft case helped establish the facts.

Jeon also changed course. He denied the charges throughout the first trial, then admitted the allegations in the indictment on appeal. He apologized publicly in court on Sept. 9. In a letter to the court, he wrote that "Samsung Electronics is the biggest victim in this case" and that he thought "an honest confession would also help prevent a recurrence."

Allegations against CXMT's leadership

Jeon testified on appeal that CXMT executives personally pressured Korean employees to hand over Samsung's technology. According to a written statement obtained by the JoongAng Ilbo, former CXMT CEO David Wang summoned Jeon and other Korean employees between October and December 2016. Wang allegedly told them: "Bring me all the Samsung process recipes and equipment information you have." The statement also quotes him as threatening, "If you don't, I'll report you to the Korean government."

Those are Jeon's account and a written statement, not findings against Wang. No court ruling in the sources establishes Wang's conduct.

A wider case and a hiring war

Jeon is not alone. At least 10 people have been charged under South Korea's Industrial Technology Protection Act in connection with the case. CXMT has also allegedly recruited at least 27 former engineers from Samsung and SK Hynix.

The talent pull is real. Jeongku Choi, a senior analyst at Counterpoint Research, told CNBC that Chinese chipmakers recruit experienced overseas engineers with high salaries, stock options, housing and family support. She said that expertise has helped them get past technical bottlenecks, especially as U.S. export restrictions limit China's access to advanced chipmaking equipment.

Choi said Chinese manufacturers, once seen as unlikely to catch up, are now "meaningful competitors." Counterpoint's Memory Tracker for the second quarter of 2026 projected CXMT would reach 10% of global DRAM revenue.

Samsung's defenses have long gone beyond the courtroom. A former employee told CNBC the company tracked where departing staff landed and used two-year non-compete clauses. The point, the person said, was to send a message that "moving to a competitor wouldn't be easy." In 2023, a South Korean court backed Samsung's bid to block a former DRAM researcher from joining Micron, finding the two-year non-compete was not excessive.

South Korea has also designated certain chip manufacturing technologies as "National Core Technologies," which raises penalties for leaking them.

What comes next

The sentence is now two weeks old, and the larger questions are still open. The remaining defendants among the at least 10 charged have yet to see their cases resolved, and those outcomes will show how the Industrial Technology Protection Act performs against organized recruitment of engineers. Park, accused of the original hand-copying, has not been brought to court. He remains under an Interpol Red Notice.

The sources do not say whether Jeon or prosecutors will pursue a further appeal.