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Micron Accuses YMTC of Taking 3D NAND Trade Secrets Through Former Engineers
Micron alleges YMTC recruited former engineers, used confidential 3D NAND know-how and built patents later asserted against Micron.
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Micron has escalated its long-running fight with YMTC
Micron has filed a new lawsuit in Idaho accusing Chinese memory maker Yangtze Memory Technologies Co., or YMTC, of obtaining confidential 3D NAND manufacturing know-how through former Micron engineers. The complaint was filed September 15, but detailed reporting on the allegations surfaced this week.
The central allegation is not simply that engineers changed employers. Micron claims YMTC deliberately recruited people who had access to confidential process information, then used that knowledge in NAND development and in patent applications. Those claims are allegations by Micron and have not been established by a court.
| Issue | Micron's allegation | Evidence boundary |
|---|---|---|
| Former engineers | YMTC recruited engineers with access to confidential Micron NAND information | Allegation in Micron's complaint |
| 3D NAND processes | Confidential know-how influenced YMTC manufacturing work from 64-layer NAND onward | Not established by a final court ruling |
| Patents | Former Micron engineers became inventors on YMTC patents covering related technology | Patent records can identify inventors; ownership and trade-secret claims remain disputed |
| Litigation | Some disputed patent families were later asserted against Micron | Part of a broader multi-jurisdiction patent conflict |
The disputed technology reaches deep into 3D NAND manufacturing
According to reporting on the complaint, Micron points to process areas including high-aspect-ratio etching, replacement-gate processing, multi-deck connections, vertical channel or pillar formation and related 3D NAND manufacturing techniques. These are manufacturing-process claims, not a dispute over a single consumer SSD feature.
Micron argues that some inventions later assigned to YMTC should instead belong to Micron under agreements signed by former employees. That ownership question matters because patents from the wider YMTC portfolio have been used in litigation against Micron.
The new case lands in the middle of a global patent war
YMTC and Micron have been fighting across several jurisdictions. Reuters reported in August that a separate YMTC lawsuit accusing Micron and DCI Group of spreading false national-security claims was dismissed by a U.S. federal judge. Other patent disputes between the memory makers have continued in the United States and Europe.
A German court also recently granted YMTC injunctions in two disputes involving 3D NAND utility models. Micron has challenged those outcomes. The new Idaho case therefore adds a trade-secret and ownership layer to an already complex patent conflict rather than replacing the earlier litigation.
Why the case matters to the NAND industry
3D NAND competitiveness depends on difficult process integration as manufacturers stack more memory layers and manage etching, channel formation, bonding and yield. A ruling that changes ownership of important process patents could affect the legal leverage between two significant NAND producers, although the current complaint does not by itself change NAND supply, SSD availability or product specifications.
The practical next steps are procedural: YMTC can contest Micron's allegations, and the court must determine whether the asserted trade secrets and ownership claims survive litigation. Until then, claims that YMTC stole Micron technology should be attributed to Micron rather than presented as established fact.
Sources
Primary and technical sources
These sources support the reporting and analysis above. Current stories are updated when later evidence materially changes the facts.