Key Points

  • The Federal Circuit affirmed Patent Trial and Appeal Board decisions holding all claims of Netlist's U.S. Patent Nos. 11,093,417 and 9,858,215 unpatentable as obvious over Perego in view of the JESD79-2 DDR2 specification.
  • The court held that motivation to combine turns on whether the combination is operable for the purposes of the claimed invention, not the intended purpose of the prior-art reference.
  • The court said a prior art reference's purpose matters only in limited cases, such as when the reference itself supplies the motivation to combine or when the defeated purpose is shared with the challenged claims, and held that neither applied.
  • The Board's motivation-to-combine findings, including JEDEC's market dominance and Perego's JEDEC-amenable embodiments, were supported by substantial evidence.
  • The appeal was decided after petitioners Samsung and Micron settled and withdrew and the Patent Office declined to intervene; the court held a live controversy remained.

The U.S. Court of Appeals for the Federal Circuit on Friday upheld Patent Office rulings that every claim of two Netlist Inc. computer-memory patents is unpatentable. The court rejected Netlist's argument that an engineer would not have combined two earlier technologies because the merged design would no longer work for one of them.

Circuit Judge Dyk wrote the opinion for a panel that also included Judges Linn and Chen. The panel affirmed two decisions of the Patent Trial and Appeal Board holding all claims of U.S. Patent Nos. 11,093,417 and 9,858,215 unpatentable as obvious.

The ruling turns on motivation to combine, the question of whether a skilled engineer would have had reason to merge the teachings of earlier references. "We conclude that the relevant question is whether the combination is operable for the purposes of the claimed invention," Judge Dyk wrote. Whether the combination still serves the earlier reference's own goals, the court held, generally does not matter.

No opponent remained in the appeal by the time the court decided it. Samsung Electronics Co. and several Micron Technology entities had brought the challenges in inter partes review proceedings before the Board. Samsung settled with Netlist before oral argument and filed a notice of nonparticipation. The Micron parties settled after argument and withdrew, and the Patent Office declined to intervene. The court said that despite the withdrawals "a live controversy regarding the patentability of Netlist’s claims remains before us for resolution."

Both patents are titled "Memory Module with Data Buffering." The claims at issue recite circuitry that acts as a buffer between a module's memory chips and the computer's memory controller, which the patent says "advantageously isolates the ranks of memory devices of the memory module." Because the buffer can add delay, the claims also recite a timing specification, known as CAS latency, that accounts for it.

The opinion described two competing industry approaches. Under standards set by JEDEC, a microelectronics standards organization, memory chips were organized into ranks selected by a "chip-select" signal from the memory controller. Rambus Inc. architecture did not use chip-select signals and instead gave each chip a unique device identifier.

Samsung and Micron argued the claims were obvious over Perego, a U.S. patent issued in 2008 that disclosed a buffer device on a memory module, combined with JESD79-2, a JEDEC specification for DDR2 memory chips published in September 2003. Perego did not disclose chip-select signals, so the challengers drew that feature from the JEDEC standard. Netlist did not dispute on appeal that the combination met every claim limitation.

Netlist argued instead that Perego disclosed only Rambus modules and that adding JEDEC chip-select signals would defeat its purpose. The company pointed to the Board's own finding that the combination "would make Perego’s system non-functional for Rambus," and said it would "cripple core functionalities described as benefits" in Perego, including backward compatibility with earlier generations of memory devices. Netlist relied on the court's 1984 decision in In re Gordon.

"Netlist misconceives the law of obviousness," Judge Dyk wrote. He quoted the Supreme Court's 2007 decision in KSR International Co. v. Teleflex Inc. that "familiar items may have obvious uses beyond their primary purposes, and in many cases a person of ordinary skill will be able to fit the teachings of multiple patents together like pieces of a puzzle." He also cited the court's 2023 decision in Axonics Inc. v. Medtronic Inc., which held it irrelevant that a modified nerve electrode could no longer stimulate the nerve the earlier reference had targeted.

The court has "often confirmed that in a motivation-to-combine analysis, 'the intended purpose of [the prior art] does not control,'" the opinion said. Here, Judge Dyk wrote, "compatibility with Rambus was not the purpose of the claimed invention, and backward compatibility was not an objective of the claimed invention." The claimed invention, he wrote, is directed to functioning in a JEDEC-compliant architecture.

The opinion identified two limited circumstances in which the earlier reference's purpose matters, and held that neither applied. The first arises when the earlier reference itself supplies the reason to combine, as in Gordon, where flipping a gasoline filter upside down would have defeated its gravity-based design. "But that is not the situation here," Judge Dyk wrote, because the challengers did not rely on Perego's Rambus features to show motivation. The second arises when the defeated purpose is shared with the challenged claims, as in Polaris Industries Inc. v. Arctic Cat Inc. and Medtronic Inc. v. Teleflex Innovations. The court held that neither Rambus compatibility nor backward compatibility with Rambus architecture "was a shared purpose of the invention."

The panel also rejected Netlist's claim that the Board violated the Administrative Procedure Act by ignoring its backward-compatibility argument. The opinion found that the Board had quoted and discussed the passage of Perego that Netlist identified.

Netlist further argued that neither the Board nor the challengers had offered any reason to combine Perego with the JEDEC standards. The court disagreed, finding the Board's reasons supported by substantial evidence. The Board had found that Perego disclosed bussed designs as an alternative to Rambus's point-to-point links, a 64-bit data width standard in JEDEC modules, and address strobe lines used in JEDEC but not Rambus architecture. Those disclosures, the court wrote, are "inconsistent with Netlist’s contention that Perego was Rambus-only."

The Board also found, relying in part on testimony from Netlist's own expert, that "JEDEC-compliant modules were dominant in the market at the relevant time." Netlist did not contest that point, and the court held that it supported the finding of motivation to combine.

Netlist was represented by William Milliken of Sterne Kessler Goldstein & Fox PLLC, who argued the appeal.

The affirmance leaves in place the Board's final written decisions holding all claims of both patents unpatentable. The Board had not reached the challengers' other obviousness grounds, and the Federal Circuit did not address them. The case is In re Netlist Inc., Nos. 2025-1286 and 2025-1296.