US Patent & Trademark Office Rejects Attempts by Canadian Solar, JinkoSolar, and Mundra Solar to Challenge Validity of First Solar TOPCon Patents - CleanTechnica

The United States Patent and Trademark Office (USPTO) has denied three Inter Partes Review (IPR) applications filed by Canadian Solar, JinkoSolar, and Mundra Solar that sought to invalidate First Solar’s Tunnel Oxide Passivated Contact (TOPCon) patents. These patents, issued in 2015 and 2017, cover manufacturing methods for TOPCon crystalline silicon photovoltaic solar cells. The USPTO’s decisions, made between November and December 2025, uphold the validity of First Solar’s US Patent Nos. 9,130,074 and 9,666,732. First Solar currently has ongoing patent infringement lawsuits against all three companies in the U.S. District Court for the District of Delaware. First Solar acquired these patents and related international counterparts through its 2013 acquisition of TetraSun, Inc., with patent protections extending to 2030 and beyond in multiple countries including the US, Australia, Canada, China, and the European Union. The company emphasized that