PTAB challenges

Proceedings overview

One AIA trial proceeding has been filed against US patent 9093473. This proceeding resulted in a discretionary denial of institution, meaning no claims were invalidated. This gives the patent owner a hardened defensive posture, as the patent has withstood a challenge at the PTAB's institution stage.

IPR2025-00879 — Taiwan Semiconductor Manufacturing Company Ltd. and [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.) v. [Marlin Semiconductor Ltd.](/litigations/by-defendant/Marlin%20Semiconductor%20Ltd.)

• Type: Inter Partes Review
• Filed: 2025-04-17
• Status: Not Instituted - Procedural. The institution was discretionarily denied by the USPTO Director.
• Judge panel: Coke Morgan Stewart, Acting Under Secretary of Commerce for Intellectual Property and Acting Director of the United States Patent and Trademark Office.
• Petition grounds: The petition challenged the patent, with the petitioner arguing that there was a "material error by the Office" related to "certain teachings in Chien770 that appear to disclose the claimed features that the patent examiner indicated were not taught by the prior art of record, including Chien770." This suggests grounds under 35 U.S.C. § 102 and/or § 103, although the specific claims challenged are not detailed in the available information.
• Institution decision: Denied (discretionary denial) on 2025-09-03. The Director found discretionary denial appropriate because a final written decision was unlikely to issue before a parallel U.S. International Trade Commission ("ITC") investigation hearing (scheduled for February 2, 2026), which would result in significant duplication of effort, additional expense, and a risk of inconsistent decisions. Additionally, the patent had been in force for ten years, creating strong settled expectations for the patent owner, and the petitioner did not provide persuasive reasoning for the IPR being an appropriate use of Board resources.
• Final Written Decision (if issued): Not applicable, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: No information regarding an appeal to the Federal Circuit is publicly available as of this date.
• Defensive value: The patent owner successfully defended against this IPR petition, as institution was denied. This means the challenged claims of US9093473 remain intact and have not been invalidated by this PTAB proceeding. For a defendant, this indicates that an IPR-based defense on the grounds raised in this petition would be more challenging, as the Director has already found reasons to deny institution.

Strategic summary

Currently, all claims of US9093473 are sustained and remain untested by PTAB proceedings on the merits. One Inter Partes Review (IPR2025-00879) was filed by Taiwan Semiconductor Manufacturing Company Ltd. and Apple Inc. but was discretionarily denied institution by the USPTO Director on September 3, 2025. The denial was based on factors such as the timing relative to a parallel ITC investigation and the patent's age contributing to "settled expectations," rather than a ruling on the merits of the prior art.

The estoppel landscape remains largely open for other potential petitioners. Since institution was denied on procedural grounds rather than a final written decision on the merits, the strict estoppel provisions of 35 U.S.C. § 315(e)(2) might not fully apply to prevent future challenges on the same or reasonably could have raised grounds by different parties. However, a future petitioner might face similar discretionary denial arguments if parallel litigation circumstances exist. The involvement of Unified Patents in other IPRs suggests an active landscape of defensive challenges in the semiconductor space, although Unified Patents was not explicitly named as the petitioner for IPR2025-00879 (TSMC and Apple Inc. were).

Recommended next steps

• As a defendant, be aware that while IPR2025-00879 did not invalidate any claims of US9093473, the patent owner prevailed at the institution stage due to discretionary denial. This means the specific prior art grounds raised by TSMC and Apple Inc. against the patent were not adjudicated on the merits by the PTAB.
• The absence of an institution on the merits means that the core patentability arguments have not been thoroughly vetted in an AIA trial. If facing assertion, consider a thorough prior art search to identify new grounds or different arguments based on the prior art previously cited in IPR2025-00879, taking into account the Director's reasons for discretionary denial.
• Given the Director's emphasis on "settled expectations" and parallel litigation in the denial of institution for IPR2025-00879, any future PTAB challenge would need to carefully address these discretionary factors, perhaps by demonstrating a material error by the examiner during prosecution or by filing early in relation to any parallel litigation.
• For specific details on the Director's decision for IPR2025-00879, refer to the document titled "Director_Discretionary_Decision@uspto.gov Paper 11" dated September 3, 2025, by searching the PTAB-TACTS system (USPTO's Patent Trial and Appeal Case Tracking System) for IPR2025-00879.