Summary of the Case

The original patent holders of this patent were: Rohm and Haas Electronic Materials CMP Holdings, Inc., and Dow Global Technologies LLC. Subsequently, the patent was transferred to: DuPont Electronic Materials Holdings, Inc., and DDP Specialty Electronic Materials US, LLC.

The two original patent holders jointly possess a large number of granted patents related to polyurethane polishing pads. They have established a comprehensive patent portfolio in CMP field, creating a patent barrier for companies involved in the research, development, and production of polyurethane polishing pads.

Kangxin was entrusted by a client to handle the invalidation of the invention patent with patent number 201410448504.X, titled "Polyurethane Polishing Pad". After that, Kangxin team that is comprised by the patent attorneys and the lawyer of litigation team of Kangxin filed a first request for invalidation in April 2023. Kangxin team conducted thorough search and preparation on the case, however, on January 2, 2024, an unfavorable decision was received, maintaining the validity of the patent rights. Subsequently, this invalidation case was selected by the CNIPA as one of the Top Ten Patent Reexamination and Invalidation Cases of 2024.

Based on the aforementioned unfavorable circumstances and following the client's instructions, Kangxin team actively cooperated with the client to diligently searched new invalidity evidences. A common knowledge evidence in the polyurethane field was sought out as the primary evidence to be combined with D1 that was also used as the closest evidence in the first request for assessing inventiveness, based on facts recognized in the first invalidation decision.

Kangxin team recombined the evidences and filed a second invalidation request against the patent, which had been transferred to new patent holders, on January 6, 2025.

Before responding to the patent holder’s response, Kangxin team repeatedly discussed relevant technical issues with the client, identified defects in the patent holder’s response, actively presented opinions, and prepared for the invalidation oral hearing. During the hearing, Kangxin team actively addressed the patent holder’s opinions, indicated out errors in the patentee’s viewpoint, effectively answered technical questions raised by the panel, and provided detailed technical analysis.

Ultimately, on July 25, 2025, Kangxin received the Invalidation Decision No. 587759, declaring the patent invalid in whole, wherein the panel highly recognized the new common knowledge evidence in polyurethane field to provide explicit teaching to the skills in the art to obtain the technical solutions in independent claims 1 & 5 and dependent claims 2-4 & 6-8. Such positive decision removed obstacles to the client's business activities and earned high praise from the client.

Challenge and Outcome

In this invalidation case, the patent was upheld as valid in the first invalidation procedure and was subsequently selected by the CNIPA as one of the Top Ten Patent Reexamination and Invalidation Cases of 2024. This posed significant challenges for the second invalidation request. Kangxin team endeavored to search out new invalidation evidence and, based on the facts recognized in the first invalidation decision, identified common knowledge evidence in the polyurethane field as the main evidence for evaluating inventive step combined with the closest prior art D1, and recombined the evidences. Prior to responding to the patentee’s response, Kangxin team engaged in repeated discussions with the client regarding relevant technical issues, identified flaws in the patentee's response, actively presented opinions, and prepared diligently for the invalidation oral hearing. During the hearing, Kangxin team actively refuted the patentee's arguments, pointed out errors therein, proactively addressed technical questions of interest to the panel, and provided detailed technical analysis. Ultimately, on July 25, 2025, the Invalidation Decision No. 587759 was received, and the patent was invalidated in whole, clearing obstacles for the client's commercial activities and earning their high praise.