[Edaily Reporter Kim Young-hwan] #YESTI has largely resolved its patent risks by winning its appeal in the patent dispute with #HPSP over the locking mechanism for high-pressure annealing equipment.

Yesti announced on the 18th that it had prevailed in the second-instance negative claim scope confirmation trial, as the Patent Court ruled that the structure of its high-pressure annealing equipment locking device does not fall within the scope of HPSP’s patent (No. 1553027). Previously, the Patent Trial and Appeal Board, which served as the court of first instance, had also ruled in Yesti’s favor on the same grounds.

The court ruled that while the core component of the HPSP patent is the “rotating locking ring” structure, Yesti’s equipment is structurally different, as it employs a mechanism where the outer door itself rotates without a rotating locking ring. The structure additionally developed by Yesti was also recognized as distinct, as it utilizes a “Single Door” method that does not include a rotating locking ring.

HPSP filed several patent amendments during the invalidation proceedings and litigation; in the second-instance invalidation trial, whose verdict was handed down on the same day, the patent’s validity was upheld. However, as the scope of the patent was limited to a specific rotating locking ring structure, the differences from Yesti’s products became even clearer.

Since HPSP filed a patent infringement lawsuit in August 2023, Yesti has responded by filing requests for review regarding five other patents held by HPSP, in addition to the locking device patent. The company assessed that the possibility of disputes has been effectively eliminated, as these patents were either ruled to be unrelated to its products or the differences became clear through patent amendments.

With the legal uncertainty resolved, the company plans to accelerate its commercialization efforts.

In March of this year, Yesti delivered a 75-wafer high-pressure annealing system to a global semiconductor company’s fab, and it plans to deliver the 125-wafer system—for which it received an order in December 2025—this coming August. The company is currently conducting wafer testing with global semiconductor firms for application in DRAM, NAND, and foundry processes, and is also pursuing joint development projects (JDPs) for next-generation DRAM processes with multiple clients.

Production of mass-production models for next-generation high-pressure oxidation (HPO) process equipment has also been completed, and the company is currently undergoing evaluations by global customers. Yesti plans to use this court ruling as an opportunity to fully enter the high-pressure annealing equipment market and expand its customer base.

A Yesti official stated, “With this ruling by the Patent Court, the legal uncertainty that had been hindering the commercialization of Yesti’s high-pressure equipment has been resolved,” adding, “In the high-pressure annealing equipment market, which was previously a monopoly, we will begin diversifying our global customer base and accelerating revenue growth starting with the delivery of our first mass-production unit in August of this year.”

High-pressure hydrogen annealing equipment is used to improve the characteristics of semiconductor silicon oxide (SiO) by replacing surface defects with high-pressure hydrogen and deuterium.