South Korean prosecutors have charged 10 individuals, including former Samsung Electronics executives, with leaking 10nm DRAM manufacturing technology to China's ChangXin Memory Technologies. The Seoul Central District Prosecutors' Office announced the indictments on December 23, 2025, with five suspects detained and five CXMT development team members charged without detention.
How they did it
The method was almost absurdly low-tech. According to prosecutors, one former Samsung researcher hand-copied over 600 manufacturing steps into handwritten notebooks over a period of years. Gas flow ratios, photoresist settings, reactor pressures: the kind of granular process data that digital security systems are designed to protect.
Those systems, it turns out, have a blind spot. Handwritten notes are nearly impossible to audit.
Samsung reportedly spent 1.6 trillion won (roughly $1.08 billion) and five years developing its 10nm DRAM process. The company was the only manufacturer mass-producing chips at that node when CXMT was founded in 2016. Prosecutors allege CXMT began recruiting Samsung talent almost immediately, bringing on a former department head as its first development director.
What CXMT allegedly got
The stolen technology allowed CXMT to begin mass-producing 10nm-class DRAM in 2023, making it the first Chinese company to hit that milestone. Prosecutors claim this shaved years off CXMT's development timeline. By mid-2024, the company had moved into HBM2 production, roughly two years ahead of what industry observers had expected.
CXMT's current capacity stands at around 280,000 wafers per month, which works out to approximately 15% of global DRAM production. For context, Micron sits at roughly 25% market share. Whether CXMT's yields actually match the incumbents remains an open question, but the scale is no longer theoretical.
The damage estimates don't quite add up
Prosecutors estimate Samsung suffered 5 trillion won in lost revenue during 2024, with broader economic damage reaching "tens of trillions of won" over time. These figures seem high, or at least incomplete. Samsung's semiconductor division lost money in 2023 for reasons that had little to do with Chinese competition, and the memory market's volatility makes attribution tricky.
What's clearer is the strategic loss. South Korea's memory industry accounts for about 20.8% of the country's total exports. Having a state-backed Chinese competitor suddenly capable of producing advanced DRAM changes the competitive math in ways that pure revenue numbers don't capture.
This isn't the first case
A separate Samsung employee received a seven-year prison sentence in February 2025 for leaking 18nm DRAM technology to the same company. SK hynix has faced its own incidents: one engineer was arrested at an airport before boarding a flight to China, allegedly carrying HBM-related documents. Another received 18 months for smuggling confidential materials in shopping bags.
The pattern suggests something more systematic than opportunistic poaching.
The shell company problem
Prosecutors allege the accused established shell companies and frequently changed office locations to avoid detection. They developed their own code words in case of travel bans or arrests. CXMT also allegedly obtained technology from SK hynix through a supplier network, though the details remain sparse.
South Korea's Industrial Technology Protection Act carries criminal penalties for overseas technology leakage. The Seoul Central District Prosecutors' Office has signaled that enforcement will intensify.
