YMTC Denies All Core Patents Invalidated; Litigation with Micron Advances Across Multiple Jurisdictions
Miles Bennett
YMTC publicly denied reports that the USPTO invalidated all its core 3D NAND patents, calling the claims 'seriously misleading.' The patent war coincides with YMTC's IPO preparation — its outcome will directly shape valuation and market credibility.
How much of the patent was actually invalidated?
The USPTO's June ruling invalidated claims 1–19 of one YMTC patent and claim 19 of another (US 11,145,666 B2) — specific claims, not entire patents.
Online accounts repackaged this as "all core patents invalidated on July 28." YMTC called the characterization factually wrong and reserved the right to pursue legal action.
This means → what fell were individual claims, not whole patent grants. But partial invalidation still matters — every claim struck from the record shrinks the ammunition available for future infringement damages.
Why is the timing so sensitive?
YMTC's parent company filed for IPO counseling on May 19, 2026, completed phase one on July 10, and is preparing to list on Shanghai's STAR Market.
Patent litigation directly affects three things: legal-risk exposure in the valuation model, risk disclosures in the prospectus, and investor confidence in the technology moat.
In plain terms = lawsuits alone don't kill an IPO, but getting labeled "all core patents invalidated" during the listing window is devastating for pricing — that is exactly why YMTC moved fast to correct the record.
Where does the legal battle stand?
YMTC sued Micron in California in November 2023 over 8 patents. By July 2024 it had expanded to 27 patents and 295 claims, covering Micron's 96-layer through 232-layer NAND products.
Micron counter-attacked through USPTO inter partes review — IPR, a process that lets third parties challenge granted patents. The USPTO rejected one Micron challenge in April 2025, then rejected two YMTC petitions in January 2026 for failing to disclose the real party in interest.
This means → neither side has won a decisive round. The litigation is now a war of attrition.
How far has the battlefield spread?
Beyond California, YMTC sued Micron and distributor Avnet in Texas in October 2025, adding 8 more patents.
Proceedings now span the UK, China, and the Unified Patent Court in Europe. Chinese patent authorities ruled in June that two Micron 3D-memory patents are partially invalid and a third is fully invalid.
Source-code access has become another flashpoint: a US appeals court ruled in February 2025 that Micron must produce materials related to its 3D NAND source code. Micron then petitioned the Supreme Court to overturn the order on national-security grounds.
This reflects something bigger than a patent dispute — it is a systematic legal confrontation across jurisdictions, wrapped in national-security rhetoric.
What gives YMTC the leverage to fight?
YMTC was the first to mass-produce 232-layer 3D NAND in 2022, becoming the world's first supplier to ship above 200 layers at scale.
Its global NAND market share rose from roughly 4.8% in 2022 to about 11% by end-2025, ranking sixth worldwide.
Current monthly capacity sits at roughly 200,000 wafers. A third fab in Wuhan is expected to add 100,000 twelve-inch wafers per month, pushing total capacity to 300,000 — enough to target a top-three position in global NAND output.
In plain terms = capacity is bargaining power. The larger YMTC's output, the heavier the pressure an injunction threat places on any competitor relying on supply stability.
What does this battle ultimately decide?
Micron CEO Sanjay Mehrotra has warned Washington that government subsidies may distort competition, citing YMTC's NAND expansion alongside CXMT's push into DRAM.
This means → the patent war is now deeply entangled with trade policy and industrial subsidies. The legal outcome matters not just for two companies but for the competitive structure of the global NAND market.
The ultimate question: who can convert technical innovation into legally protected scale — a question far larger than any single court ruling.
Content is for reference only, not financial advice.