First Solar Sues JA Solar and Corning’s US Panel Plant Over TOPCon Patent

First Solar has sued Chinese rival JA Solar and a Corning-owned factory in Arizona over patented methods for making TOPCon solar cells, opening a new front in a patent fight that the Arizona-based manufacturer had, weeks earlier, scaled back at the US trade border in favor of pressing it in court instead.

The company filed suit on October 2 in the US District Court for the District of Delaware against four JA Solar entities — JA Solar Technology, JA Solar International, JA Solar Vietnam and JA Solar Industrial — and American Panel Solutions (AMPS), a wholly owned subsidiary of glass and materials maker Corning Incorporated, according to court filings reported by PV Tech. The complaint alleges infringement of US Patent No. 9,130,074, which covers methods of manufacturing tunnel oxide passivated contact (TOPCon) crystalline-silicon solar cells — now the dominant cell architecture used by most Chinese and global module makers.

A thin-film maker enforcing a silicon patent

First Solar is best known for cadmium telluride (CdTe) thin-film panels, a technology distinct from the crystalline-silicon cells at the center of this case. It picked up the contested patent through its 2013 acquisition of TetraSun, a silicon-cell startup that never reached mass production. More than a decade later, as TOPCon cells have displaced older PERC designs and eaten into First Solar’s share of the US utility-scale market, the company has turned that dormant intellectual property into a legal weapon against the manufacturers driving the shift. Since 2024, First Solar has filed similar TOPCon suits against JinkoSolar, Canadian Solar, Trina Solar and T1 Energy, all built around the same patent family.

Why the timing follows a trade-policy pivot

The Delaware filing lands less than three weeks after First Solar said, on September 15, that it would voluntarily withdraw its parallel Section 337 complaint at the US International Trade Commission, without prejudice to refiling later. That case — Investigation No. 337-TA-1494, filed February 24 and supplemented March 10, with the ITC voting to institute it on March 25 — had named respondents tied to Canadian Solar, JA Solar, JinkoSolar, Trina Solar, Hanwha Qcells, Axitec Solar, Runergy, Philadelphia Solar, VSUN, Toyo and Adani-linked Mundra Solar, 47 entities in all across 11 countries. First Solar had asked the ITC for a general exclusion order that could have blocked TOPCon-based imports regardless of which company made them.

First Solar said the withdrawal followed the Trump administration’s Section 232 action on polysilicon, announced in early August, which imposes a 15% tariff and a minimum import price on polysilicon and its derivatives — ingots, wafers, cells and modules — from December 4. With that tariff already working to curb low-cost Chinese-linked supply, First Solar said it would rather concentrate its legal resources on the district court lawsuits, including the stayed cases against Canadian Solar, Jinko, T1 Energy and Trina, which can now proceed. The JA Solar and AMPS suit is the first new case filed since that shift.

Why a Corning-backed US factory is a defendant

AMPS stands out among the defendants because it isn’t an importer at all: Corning bought the plant, a 2-gigawatt module-assembly line in Phoenix, directly from JA Solar to anchor what it has promoted as a fully domestic supply chain, pairing the Arizona line with polysilicon and wafers from Corning’s Michigan operations and solar cells from Suniva’s Georgia factory. That venture was built in part around the extra tax credits the US offers for domestically produced solar content — the same policy backdrop now reinforced by the Section 232 tariff. By naming AMPS, First Solar is arguing that relocating assembly onto US soil does not clear a manufacturer of liability if the underlying cell-making process still relies on patented TOPCon steps.

A district court suit is a separate legal track from the ITC’s import-exclusion process: it can produce damages and an injunction against the specific defendants named, but it cannot block other companies’ imports the way a general exclusion order would have. Litigation of this kind typically runs well over a year before trial. First Solar has not disclosed the damages it is seeking, and neither JA Solar nor Corning had issued a public response to the suit at the time of writing.

Sources

• PV Tech, “First Solar files TOPCon patent infringement lawsuit against JA and Corning subsidiary,” October 2026 — filing date, court, defendants, patent number. pv-tech.org
• pv magazine USA, “First Solar drops TOPCon patent complaint,” September 17, 2026 — ITC withdrawal, Section 232 rationale, status of district court cases. pv-magazine-usa.com
• Solar Power World, “First Solar ends Sec. 337 investigation into competitors allegedly infringing on TOPCon patent,” September 2026 — ITC case scope and respondents. solarpowerworldonline.com
• PVTime, “Corning Acquires JA Solar’s Arizona Solar Plant to Bolster US Manufacturing Presence” — background on the AMPS Phoenix plant. pvtime.org
• The Daily Energy, “US Solar Module Prices Jump More Than 40% as Section 232 Tariff Takes Hold” — tariff mechanics and market impact. thedailyenergy.com

Illustrative image. Photo: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons — source