Inter Partes Review applications denied as First Solar lawsuits continue to progress

First Solar, Inc. (Nasdaq: FSLR) ("First Solar") today announced that the Director of the United States Patent and Trademark Office (USPTO) denied three separate Inter Partes Review (IPR) applications seeking to invalidate the company's Tunnel Oxide Passivated Contact ("TOPCon") patents through a review process. The IPRs were filed by JinkoSolar, Mundra Solar, and Canadian Solar in 2025, and were declined on November 20, December 11, and December 18, respectively.

While JinkoSolar and Canadian Solar sought to invalidate First Solar's US Patent No. 9,130,074, Mundra Solar's application sought a review of First Solar's US Patent No. 9,666,732. Both patents cover methods of manufacturing TOPCon crystalline silicon ("c-Si") photovoltaic (PV) solar cells. First Solar has pending lawsuits against all three companies alleging infringement of its patents in the United States District Court for the District of Delaware.

"First Solar believes the USPTO properly exercised its discretion in each of the cases brought by Jinko, Canadian Solar and Mundra," said Jason Dymbort, Executive Vice President, General Counsel and Secretary, First Solar. "We believe that this is consistent with USPTO's ‘Settled Expectations' doctrine, which is underpinned by the principle that the longer a patent has been in force, the stronger and more settled the patent owner's expectations should be. The patents at issue in each of these matters were issued in 2015 and 2017, respectively, long before each of these manufacturers' petitions were filed."

Dymbort added, "The USPTO's decision reinforces our belief in the strength of our TOPCon technology patent portfolio. As we've consistently stated, we will actively defend our intellectual property rights in the US and internationally and continue to pursue legal action against these and other manufacturers, as we work to enforce our patent rights."

First Solar obtained the US TOPCon patents and related international counterparts through its 2013 acquisition of TetraSun, Inc. The patents include issued patents in the United States, Australia, Canada, China, the European Union, Hong Kong, Japan, Mexico, Malaysia, Singapore, South Korea, the United Arab Emirates, and Vietnam with validities extending to 2030 and beyond. The portfolio also includes pending patent applications in the European Union, Japan, Hong Kong, United Arab Emirates, and Vietnam. In July 2024, First Solar announced its intention to license and enforce the TOPCon technology patent portfolio and the launch of infringement investigations against several leading crystalline silicon solar cell manufacturers.

About First Solar, Inc.

First Solar, Inc. is America's leading PV solar technology and manufacturing company. The only US-headquartered company among the world's largest solar manufacturers, First Solar is focused on competitively and reliably enabling power generation needs with its advanced, uniquely American thin film PV technology. Developed at research and development (R&D) labs in California and Ohio, the Company's technology represents the next generation of solar power generation, providing a competitive, high-performance, and responsibly produced alternative to conventional crystalline silicon PV modules. For more information, please visit www.firstsolar.com.