HPSP-YESTI Patent Dispute Over HPA Equipment to Be Decided in June

Gate News message, April 15 — A South Korean patent court will render its verdict in June on a critical patent dispute between HPSP and YESTI over high-pressure hydrogen annealing (HPA) equipment. While the two companies are contesting six HPSP patents in total, the court’s decision on one core patent—which HPSP used when filing an infringement lawsuit against YESTI in 2023—could significantly shift the entire dispute in one party’s favor.

The patent in question is HPSP’s “chamber opening and closing device for semiconductor substrate processing” (Registration No. 1553027). YESTI had previously filed both an invalidation petition and a negative scope-of-rights confirmation petition with the Patent Trial and Appeal Board (PTAB). The PTAB upheld HPSP’s patent validity in the invalidation case but ruled in YESTI’s favor in the negative scope-of-rights case. Both parties appealed their unfavorable decisions to the patent court, resulting in three cancellation suits scheduled for June ruling.

During the proceedings, HPSP requested a patent amendment petition, which the PTAB approved in February. A key dispute has emerged over which patent scope—pre-amendment or post-amendment—should apply to the negative scope-of-rights confirmation case. HPSP claims it should use the pre-amendment scope, while YESTI argues the post-amendment scope should apply. In its filing, HPSP noted that it supplies equipment to major semiconductor companies including Samsung Electronics, SK Hynix, and TSMC, demonstrating the patent’s contribution to its competitive advantage. YESTI, which announced in December 2025 that it would supply HPA equipment to two major global semiconductor manufacturers, has separately challenged five additional HPSP patents and is currently leading in those disputes.