Key points
- Micron sues YMTC over former engineers
- Micron seeks ownership of four YMTC patents
- YMTC is already suing Micron on three continents
Micron Technology (MU) has sued China's Yangtze Memory Technologies, or YMTC, accusing the chipmaker of using former Micron engineers to obtain its 3D NAND trade secrets. Micron filed the complaint in federal court in Idaho on Sept. 15, and it also asks the court to transfer ownership of four YMTC patents to Micron.
Micron says it found the problem while defending itself. YMTC has been suing Micron for patent infringement since 2023, and several of those patents name former Micron engineers as inventors.
What does Micron allege?
The 103-page complaint names YMTC and Hongbin Zhu, a former Micron process engineer, as defendants. Zhu worked at Micron's Boise campus from January 2006 to September 2017, according to the complaint. It says YMTC targeted Micron's Idaho workforce and used Zhu and other former employees to get access to Micron's trade secrets.
According to the complaint, five Micron employees left in mid-2017. Three worked at the Boise campus, including Zhu, and cited family reasons for leaving. Several didn't update their LinkedIn profiles to show their new jobs at YMTC. As of July 2026, Zhu's profile still listed him as a Micron engineer, Micron says.
Micron alleges YMTC used the information to develop its 64-layer, 128-layer, and 232-layer NAND chips. It's bringing claims under federal and Idaho trade secret laws, along with a breach-of-contract claim against Zhu.
Why does Micron want YMTC's patents?
Micron argues that the inventions covered by the four patents fall under agreements the former engineers signed assigning inventions to the company. On that basis, it says YMTC is not the rightful owner.
Micron is asking the court to declare it the owner of four U.S. patents and to order YMTC to transfer them. One, U.S. Patent No. 10,707,851, is a patent YMTC has asserted against Micron in Texas. Micron is also seeking an injunction, damages, and a share of YMTC's profits from the alleged misappropriation.
How big is the fight with YMTC?
YMTC first sued Micron in Northern California in November 2023. It has since filed cases in Texas, China, the U.K., and Germany, along with Europe's Unified Patent Court, according to Tom's Hardware. The U.S. Commerce Department added YMTC to its Entity List in December 2022, restricting its access to American chipmaking tools.
In September, a Munich court ruled that Micron infringed two YMTC utility models, a form of intellectual-property protection distinct from patents, and granted injunctions. Micron has appealed. Tom's Hardware reported that both appear to belong to patent families naming a former Micron engineer. Micron's Idaho complaint doesn't mention the German case.
The docket doesn't yet show a response from YMTC. YMTC's parent applied in August for a Shanghai listing to raise about $4.9 billion, and Micron on Wednesday reported $54.2 billion in quarterly revenue as memory prices climbed.
