harmless error Archives

APA compliant? Board’s use of invalidity basis not raised in IPR petition may be harmless

by Cecilia Choy, PhD and Lisette Donewald | Sep 17, 2026 | Patents

The US Court of Appeals for the Federal Circuit concluded that the Patent Trial & Appeal Board’s use of a reference that was not urged by the petitioner in an inter partes review (IPR) petition was harmless since the Court agreed with the Board’s analysis and conclusion that all challenged claims were unpatentable as obvious on alternative grounds raised in the petition. Netlist, Inc. v. Micron Technology, Inc., Case No. 2024-1707 (Fed. Cir. Sept. 2, 2026) (Reyna, Linn, Stark, JJ.)

Netlist owns a patent directed to improving the performance and memory capacity of memory boards. The patent describes using buffers between a memory controller and memory devices. Those buffers contain data paths that can be selectively enabled during read and write operations. Samsung filed a petition for IPR challenging certain claims of the patent as obvious over the combination of two prior art patents, Ellsberry and Halbert. The Board instituted review and determined that Samsung met its burden to show that the challenged claims were obvious over Ellsberry alone or in combination with Halbert. Netlist appealed.

The Federal Circuit reviewed the Board’s decision for compliance with the Administrative Procedure Act (APA) and agreed with the Board’s technical review of the prior art in finding the challenged claims obvious. The APA requires that a Board decision identify the reasons and bases in the record for reaching its conclusions. In an IPR proceeding, this generally requires the Board to proceed in accordance or conformance with the challenge grounds presented in the IPR petition, and the Board may not “depart from the petition and institute a different IPR of its own design.” In the past, the Federal Circuit has found error where the Board held claims unpatentable based on grounds that were not urged by the IPR petitioner.

Netlist argued that even if the Board had substantial evidence to find that Ellsberry taught most limitations at issue, the Board erred by using a Netlist patent in its analysis to fill a gap in terms of a claimed limitation. The Board cited the Netlist patent for its teaching that an additional clock cycle could account for delay as data traveled through a buffer. Netlist argued that it was improper to use the Netlist patent to supply a teaching of a claim limitation when Samsung did not present this reference as an invalidity ground in its IPR petition. Netlist argued that the Board expanded the role of the Netlist patent from being mere evidence of general skill in the art to that of a prior art reference in violation of the APA restriction against departing from the petition to find claims invalid on grounds of “its own design.”

The Federal Circuit concluded that any potential error arising from the Board’s use of the Netlist patent was harmless since the Board found alternatively that Ellsbery alone without relying on the Netlist patent taught the limitations in the challenged claims.

Practice note: The decision leaves unresolved when the Board’s use of a reference not relied on in the [...]

Continue Reading

It’s Obvious: Erroneous Claim Construction Can Be Harmless

by Taylor MacDonald | Feb 13, 2025 | Patents

The US Court of Appeals for the Federal Circuit affirmed a Patent Trial & Appeal Board obviousness determination even though it found the Board had improperly construed a claim term, because the Court found the error harmless in the context of the prior art. HD Silicon Solutions LLC v. Microchip Technology Inc., Case No. 23-1397 (Fed. Cir. Feb. 6, 2025) (Lourie, Stoll, Cunningham, JJ.)

During a 2022 inter partes review (IPR), the Board determined that all but one of the 17 challenged patent claims were unpatentable as obvious in light of a prior patent (Trivedi) and other secondary prior art. The patent described methods of creating “a local interconnect layer in an integrated circuit” using two films. The independent claim recited a first film composed of titanium nitride and a second film as “comprising tungsten.” The Board construed “comprising tungsten” to include either elemental tungsten or tungsten-based compounds. The Board also found that the Trivedi patent disclosed films comprising either elemental tungsten or tungsten compounds. Thus, the Board held that all claims except one were obvious in light of Trivedi and that a person of ordinary skill in the art would have been motivated to combine Trivedi with other prior art. The patent owner appealed, arguing that the Board’s obviousness finding was dependent on the Board’s incorrect construction of the phrase “comprising tungsten.”

The Federal Circuit agreed that the Board’s claim construction was erroneous, because the term “comprising tungsten” required elemental tungsten. The Court explained that the claims explicitly used compound names when referring to compounds, such as “titanium nitride.” Thus, when the drafters wrote “comprising tungsten” without more, they clearly intended to exclude non-elemental tungsten options. The Court also noted that the patent specification used “tungsten” to reference only elemental tungsten and used the word “based” to encompass both elements and their compounds. For example, the patent discussed “chlorine-based” and “fluorine-based” components. Thus, the Court concluded that the claim drafters knew how to delineate when terms should include compounds, and that there was no such delineation in the term “comprising tungsten.”

The Board relied on a single sentence in the patent that stated: “the second film may comprise tungsten, for example,” to support its construction. The Federal Circuit rejected such a broad reading of this language, explaining that it only provided for impurities mixed among the elemental tungsten in the second film, rather than the film comprising a tungsten compound. The Board also cited a European Union (EU) patent in support of the construction that “comprising tungsten” explicitly included tungsten compounds. The Court stated that such extrinsic evidence was insufficient to overcome the asserted patent’s intrinsic teachings.

The Federal Circuit analyzed whether the Board’s obviousness holding could stand given its erroneous construction. The Court found that because the Board determined that Trivedi disclosed layers made of a tungsten compound and elemental tungsten, the patent claims were obvious when the disputed term was properly construed to be limited to elemental tungsten. Thus, the Board’s error was harmless.

Jury Trial on Legal Issue Denied, But No Harm Done

by Keval Amin | Aug 29, 2024 | Trade Secrets

The US Court of Appeals for the Seventh Circuit affirmed a district court’s denial of a jury trial, concluding it was harmless error because the defendant would have been entitled to a directed verdict regardless. Overwell Harvest Ltd. v. Trading Techs. Int’l, Inc., Case No. 23-2150 (7th Cir. Aug. 12, 2024) (Kirsch, Pryor, Kolar, JJ.)

Overwell Harvest was established to invest in Neurensic, a company specializing in market surveillance technology. Despite Overwell’s investment of millions of dollars, Neurensic faced significant financial distress, leading its management to pursue a sale. Neurensic’s CEO and COO accepted an offer from Trading Technologies, which subsequently hired former Neurensic employees with the CEO and COO’s approval. Prior to the sale, Overwell submitted a competing bid, to which Trading Technologies responded by raising its offer. Neurensic chose to accept Trading Technologies’ offer.

Overwell sued Trading Technologies for aiding and abetting breaches of fiduciary duties by Neurensic’s leadership. The district court dismissed Overwell’s jury demand and ruled that the claim was equitable despite the damages sought. In a bench trial, the district court ruled in favor of Trading Technologies, determining that Overwell waived its claims that Trading Technologies had aided and abetted breaches of fiduciary duty by Neurensic’s leadership. The district court’s decision was based on Overwell’s failure to advance arguments concerning improper notice to shareholders regarding the vote on Trading Technologies’ offer. Overwell appealed.

The Seventh Circuit decided that Overwell had a Seventh Amendment right to a jury trial because the case involved legal relief in addition to equitable relief. While the Court agreed that Overwell’s claim for aiding and abetting breaches of fiduciary duty under Delaware law was historically equitable, the request for compensatory and punitive damages constituted legal relief. The Court emphasized that even if a claim is equitable, the pursuit of legal relief (such as money damages) entitles a party to a jury trial. The Seventh Circuit determined that the district court erred by denying Overwell this right because determining legal relief is traditionally the role of a jury.

The Seventh Circuit concluded that this error was harmless, however, because under Delaware law Trading Technologies would have been entitled to a directed verdict. The Court explained that a directed verdict is appropriate when no reasonable jury could find for the losing party based on the evidence, viewing the record in the light most favorable to the losing party.

The Seventh Circuit rejected Overwell’s breach of fiduciary duty claims, finding that the alleged breaches lacked merit under the Delaware standard for aiding and abetting fiduciary breaches. First, the Court held that Overwell failed to show that Trading Technologies knowingly participated in a fiduciary breach, as the continued servicing of Neurensic’s customers by former employees benefitted Neurensic, not Trading Technologies.

Second, the Seventh Circuit determined that Overwell’s claim of blocking competitive bids could not succeed as Neurensic still held its most valuable asset – its source code – and could have repossessed its servers. Trading Technologies’ negotiation tactics were permissible under Delaware law, which allows [...]

Continue Reading