YMTC wins first round in Micron case over NAND technology

The claims form part of a multi-jurisdictional dispute between the parties, which involves proceedings in the US, the UK and China in addition to Germany and the UPC. They all relate to 3D NAND flash memory for flash memory devices, which are used worldwide in hard drives and other storage media, including those for PCs.

Yangtze Memory Technologies (YMTC) accuses Micron of infringing a number of technical protection rights with their products. Following litigation in the US, the Chinese company filed actions against the US competitor at the Regional Court Munich in October last year. The actions concern EP 3 931 868 and the four utility models DE 20 2020 006 166.2, DE 20 2021 004 551, DE 20 2018 007 011 and DE 20 2022 003 278.

Deep dive into validity

After nearly two full days of oral hearings, the 7th Civil Chamber under presiding judge Oliver Schön found two of the utility models, DE551 and DE166, valid and infringed and granted YMTC injunctions (case IDs: 7 O 12614/25 and 7 O 12615/25). Micron appealed the decisions. During the hearing the judges took a deep dive into the validity of the utility models, which, unlike patents, are only valid for a maximum of 10 years and do not require an examination at application.

In the case of the other two utility models, DE 011 and DE 278, the judges adjurned the proceedings. The court has scheduled further hearings for June and September of next year (case IDs: 7 O 12609/25 and 7 O 12616/25). Regarding EP 868, the EPO had handed down a preliminary opinion in parallel opposition proceedings on 8 September. However, the 7th Civil Chamber also adjourned this case to a later oral hearing in September 2027 (case ID: 7 O 12593/25).

Micron fights back

YMTC also filed parallel infringement claims at the UPC’s local division Düsseldorf over EP 3 909 047, EP 3 850 660 and EP 4 236 650 (case IDs: UPC-CFI-0001034/2025, UPC-CFI-0001041/2025 and UPC-CFI-0001042/2025). The court has scheduled oral hearings in these cases for February next year. Actions over the same patents are also pending at the UK High Court, where a case management conference takes place today (case ID: HP-2025-000048).

Micron has now retaliated against YMTC with an action concerning its own patent. In mid-July the US company filed an infringement claim against the Chinese competitor at the Regional Court Munich over EP 3 706 127. The oral hearing will take place in June 2027.

Micron has also launched parallel proceedings at the UPC over EP 3 574 526 in Düsseldorf and EP 2 745 295 in Mannheim (case IDs: UPC-CFI-0002660/2026 and UPC-CFI-0002556/2026). The defendants are the computer hardware manufacturer Ultron and the two providers of digital storage solutions Lexar and Apacer Technology. The latter two as well as Team Group are also defendants alongside YMTC in an action Micron has recently launched at the UK High Court (case ID: HP-2026-000027).

Chinese contact

In the dispute over the utility models, Yangtze Memory Technologies retained an international team from mixed IP boutique Hoyng ROKH Monegier. Klaus Haft led the case at the Regional Court Munich, working with Amsterdam-based partners and patent attorneys Andrew Lin and Christopher Pierce.

The team comprised Sven Krause, Elisa In den Birken and Alexander Bothe. The validity aspect was argued by patent attorneys Wolfgang Lippich, Georg Jacoby, Cletus von Pichler of Munich firm Samson & Partner. The patent attorney team also included Stefan König, Matthias Göpfert and Alexander Ruschke.

A team from Bird & Bird represented the Chinese company in the Munich proceedings regarding the EP 868, as well as in all the UPC actions regarding the assertion of YMTC’s patents. The initial contact came through Bird & Bird partner Christina Yiu from the Shanghai office. Düsseldorf-based partner Oliver Jüngst is in the lead, working with patent attorney and partner Felix Landry. The team includes lawyer Lucas Brons and patent attorney Leonard Lotz as counsel and associate Niklas Kabel. Bird & Bird is also acting for the client in the parallel UK proceedings.

According to the UPC register, the three defendants in the active UPC actions filed by Micron have retained lawyers from Vossius & Partner and Stein & Partner.

In all proceedings at the Regional Court Munich and the UPC, Micron has instructed Bardehle Pagenberg with lead partner Tilman Müller-Stoy alongside partners and litigators Tobias Wuttke, Jan Bösing and Stefan Lieck. Patent attorneys and partners Christof Karl, Tobias Kaufmann, Niels Malkomes, Patrick Daum, and Daniel Werner advised on the technical side of the case. The team also included patent attorneys Benedikt Dellen, Philipp Bovenkamp, Jakob Scheffel, Sabrina Hütt, Thomas Kotzott, and patent engineer Andreas Aigner, as well as associate Lisa Engelbert. In the dispute at the UK High Court, Jones Day is acting for the US company.d