US-based solar technology and manufacturing company, First Solar, has filed a lawsuit against JA Solar and American Panel Solutions (AMPS), alleging unauthorized use of a patent related to tunnel oxide passivated contact (TOPCon) technology .

The U.S. Patent No. 9,130, 074 covers methods for manufacturing TOPCon crystalline silicon solar cells.

The lawsuit was filed in the U.S. District Court for the District of Delaware. It names several JA Solar companies, namely JA Solar Technology, JA Solar International, JA Solar Vietnam, and JA Solar Industrial, along with AMPS.

The lawsuit comes weeks after First Solar announced its decision to withdraw its Section 337 patent complaint before the U.S. International Trade Commission and continue pursuing lawsuits over TOPCon technology in U.S. District Court.

First Solar alleged that these companies used its patented technology without authorization. It stated that it intends to defend its intellectual property rights in the U.S. and other markets.

First Solar obtained the U.S. TOPCon patents and related international counterparts through its acquisition of TetraSun in 2013.

According to First Solar, the patent portfolio includes issued patents in the U.S., Australia, Canada, China, the European Union, Hong Kong, Japan, Mexico, Malaysia, Singapore, South Korea, the United Arab Emirates, and Vietnam. The patents remain valid through 2030 and beyond.

The portfolio also includes pending patent applications in the European Union, Japan, Hong Kong, the United Arab Emirates, and Vietnam.

Last year, First Solar filed a lawsuit against Shanghai-headquartered JinkoSolar, alleging patent infringement of its TOPCon modules.

In July 2024, First Solar announced that it owned the TOPCon patent portfolio and had begun infringement investigations involving several crystalline silicon solar cell manufacturers.

In the second quarter of 2026, First Solar reported net sales of $1.06 billion, a 3.7% year-over-year decline from $1.1 billion. Revenue was broadly in line with analysts’ expectations.