How the Samsung, SK Hynix, Semes, and OLED Cases Expose the Real Pathways of Korean Technology Leakage
June 29, 2026By Jean CummingsCo-Editor-in-Chief and Senior Columnist, The Korea Signal
The U.S. congressional Armed Services Committees’ request in the FY2027 National Defense Authorization Act report for the Secretary of Defense to assess the “malicious influence of the Chinese Communist Party inside South Korea” did not arise from abstract diplomatic concern alone. It reflects a series of concrete incidents that have already surfaced repeatedly inside South Korea. Among the most serious areas are semiconductor talent recruitment and technology leakage.
China does not view South Korean semiconductor companies merely as commercial competitors. It has worked to narrow the technology gap by directly recruiting engineers, researchers, process specialists, equipment operators, and yield managers who gained hands-on experience at companies such as Samsung Electronics and SK Hynix.
What China wants is not a degree or a title. It wants technical personnel who have accumulated real mass-production experience inside Korean semiconductor companies.
As the United States has moved to block the flow of advanced semiconductor equipment, AI chips, and core manufacturing technology into China, Beijing has shifted toward taking Korean technical personnel instead of simply buying equipment. In effect, China is using the experience and shop-floor knowledge of Korean semiconductor engineers to bypass U.S. technology controls.
The Attempt to Replicate a Samsung Semiconductor Fab in China
The most symbolic case involved a former Samsung Electronics executive who allegedly attempted to replicate a Samsung semiconductor fabrication plant in China.
On June 12, 2023, Korean prosecutors indicted a former Samsung executive on charges of stealing Samsung technology to establish a copycat semiconductor plant in China. Prosecutors treated the case as a major threat to South Korea’s national economic security.
The individual, identified as A, was accused of taking Samsung semiconductor factory design materials, BED files, process layouts, and factory blueprints in order to build a semiconductor plant in China. The technologies involved were sub-30 nanometer DRAM and NAND flash process technologies, classified as national core technologies.
The key point in this case is that this was not merely the removal of a few documents. According to prosecutors, A and his associates attempted to build a Samsung-style semiconductor plant only about 1.5 kilometers away from Samsung’s existing plant in Xi’an, China, and the plan also included personnel recruitment. A offered Korean semiconductor personnel twice their salary and recruited roughly 200 people into his company. He also secured a 460 billion won investment commitment from the city of Chengdu.
This was not a simple technology leak. It was an attempt to move to China the factory design, line layout, production operation methods, and field personnel that Korean companies had built over decades.
The same former Samsung executive, Choi Jin-seok, was later detained again on new allegations related to the theft of 20-nanometer-class DRAM process technology. He had already been on trial over the earlier allegation involving a copycat semiconductor plant in China, and the new allegations reportedly involved Samsung chip process technology. Choi has denied the charges, but the case shows that the attempted relocation of Korean semiconductor process technology and personnel to China was not a one-time incident.
The Samsung 10-Nanometer-Class DRAM Technology Leak to CXMT
A more direct case emerged in December 2025. Korean prosecutors indicted ten former Samsung executives and engineers on charges of leaking advanced memory manufacturing technology to ChangXin Memory Technologies, or CXMT. The companies involved were Samsung Electronics and China’s CXMT. The leaked technology was Samsung’s 10-nanometer-class DRAM process technology, which Samsung had reportedly spent about 1.6 trillion won to develop.
CXMT is China’s first DRAM semiconductor company, established in 2016 with investment from a Chinese local government and a Chinese semiconductor design company. According to prosecutors, shortly after its founding, CXMT hired a former Samsung department head as its development director. That individual then recruited key process personnel in order to obtain Samsung’s 10-nanometer-class DRAM process technology.
In the course of this operation, they allegedly created a front company, moved offices repeatedly, and even agreed to send specific code words if a travel ban or arrest situation occurred.
The most shocking detail was that a Samsung researcher, identified as B, directly copied by hand PRP information — process recipe information at the heart of DRAM production — before moving to CXMT.
Prosecutors said B copied 600 process steps by hand into 12 employee notebooks and carried them out. Normally, technology leak cases involve file copying, photography, email transmission, or USB storage. In this case, however, handwritten transcription appeared. More than 600 process steps, gas flow rates, photoresist conditions, and other core manufacturing conditions were recorded by hand.
According to prosecutors, CXMT later recruited additional Samsung employees and began DRAM development. It also obtained process-related technology from SK Hynix through suppliers. As a result, CXMT became the first Chinese company to succeed in producing 10-nanometer-class DRAM in 2023. Prosecutors estimated that this case alone caused Samsung 5 trillion won in lost sales in 2024, and that broader national economic damage could reach at least tens of trillions of won.
The HBM connection is the part that must not be missed. Prosecutors determined that the illegal use of this technology provided the foundation for CXMT’s HBM development. This means the DRAM technology leak did not stop at ordinary memory technology. It could lead directly into high-bandwidth memory, or HBM, which is essential for AI computation.
On April 22, 2026, a Korean court sentenced a former Samsung researcher to seven years in prison for leaking semiconductor manufacturing technology to CXMT, after finding that the leaked information constituted national core technology.
This case shows how precise China’s talent recruitment strategy has become. Chinese companies knew which technologies they needed from Korean semiconductor firms, identified the people who possessed them, and selected them for recruitment. Moreover, they did not stop with one person. They recruited additional key personnel by process area and connected those people to China’s own production capability.
From the U.S. defense perspective, this case is highly direct. DRAM and HBM are core components in AI servers and advanced computing systems. If China obtains Korean DRAM manufacturing technology and process recipes, China’s AI semiconductor ecosystem gains breathing room even under U.S. sanctions. The United States is blocking AI chips and advanced equipment, but China is trying to reduce production problems by recruiting people trained in Korea who have actually handled those processes. This is sanctions evasion through people.
The United States is working to prevent advanced semiconductor technology and manufacturing capability from flowing into China by strengthening equipment export controls and technology access restrictions. However, if semiconductor manufacturing personnel trained in Korea, along with people who have factory operation experience and production-line design experience, move to China, Beijing can accelerate development even under U.S. sanctions. Sanctioning China alone will not stop technology leakage. If Washington does not block talent movement and technology leakage through Korea, one of the leading countries in semiconductor technology, China will continue to use Korea as a bypass route.
That is why Washington must watch Korea more closely.
The case is significant in that core South Korean semiconductor technologies were leaked over an extended period and left unaddressed during the Moon Jae-in administration, which maintained close ties with China and North Korea. Comprehensive investigations and indictments began only in 2023 under the Yoon Suk Yeol administration, but the final ruling was substantially delayed. In the interim, damages continued to accumulate. The compromised technologies were incorporated into Chinese firms’ production lines and development systems, enabling CXMT to advance its technical capabilities. By the time South Korea secured convictions, the relevant DRAM process had already become nearly a decade old due to generational shifts in semiconductor technology. China had already secured the transferred capabilities, while South Korea had lost market share and competitiveness. Accordingly, while the ruling establishes legal accountability, it is difficult to avoid the conclusion that justice was delivered too late to mitigate the national-level damage.
