Prevailing on all claims in a patent invalidation action relating to hafnium precursors

In 2021, Versum Materials Korea (“Versum”) filed a patent invalidation action against Tri Chemical Laboratories (“Tri Chemical”) regarding a thin film formation material patent. Lee & Ko, representing Tri Chemical, the patentee, successfully defended the patent’s validity at the Intellectual Property Trial and Appeal Board (“IPTAB”) in July 2023. Although Versum subsequently filed an appeal with the IP High Court to revoke this decision, the IP High Court also upheld the patent’s validity on August 22, 2024 (prevailing on all claims), and this ruling was rendered final and conclusive on September 14, 2024.

The patent at issue directs to Cp hafnium compounds used as thin film formation materials, which are representative high-dielectric materials used to form insulating films at the ends of semiconductor DRAM capacitors or metal gates. This patent is considered so significant in the industry that it is valued at over KRW 1 trillion.

Versum argued that the patent lacked inventiveness as the patented compound was structurally similar to compounds disclosed in prior art references and could be easily derived. In response, Lee & Ko not only successfully articulated the legal principle that in the chemical field, even if compounds show structural similarities, the patent’s inventiveness cannot be readily denied if there are unpredictable and significant differences in effects. Lee & Ko also clearly demonstrated these differences by conducting and presenting comprehensive comparative experiments between the patented compound and prior art compounds.

As a result, both the IPTAB and the Patent Court determined that the patent could not be invalidated due to its unpredictable and significant effects compared to prior art compounds, successfully defending the patentee’s rights. The ruling serves as an important precedent regarding the finding of inventiveness in compound-related inventions.

This case attests to Lee & Ko’s Intellectual Property Group’s superb capabilities and expertise, as it successfully protected an enormously crucial patent from invalidation attempts through more than three years of persuasive arguments in hearings, grounded in  thorough technical review and legal analysis.