Federal Circuit Vacates PTAB Decision Invalidating Rambus Patent

In Rambus, Inc. v. Rea, the Federal Circuit found several legal and procedural errors in the decision of the USPTO Patent Trial and Appeal Board (PTAB) that invalidated certain claims of the Rambus patent as obvious. While the technology at issue goes beyond the scope of PharmaPatentsBlog, the decision makes several important points of general interest.

The USPTO Proceedings

This case arose from an inter partes reexamination of Rambus’ U.S. Patent 6,260,097, which is directed to memory circuits known as dynamic random-access memory (DRAM). The Examiner found certain claims to be invalid as anticipated or obvious. The PTAB affirmed the rejections, and Rambus appealed.

The Federal Circuit Decision

The Federal Circuit opinion is authored by Judge Moore and joined by Judge Linn and Judge O’Malley.

Because the claims at issue are directed to DRAM, and my background is in chemistry and biotechnology, I will leave a discussion of the technical issues (such as claim construction) to others, and focus on the points of more general relevance that caught my attention.

The Burden Of Proof In Reexamination Proceedings

The Federal Circuit found that the PTAB “erroneously placed the burden on Rambus to prove that its claims were not obvious,” noting that “[i]n reexamination proceedings, ‘a preponderance of the evidence must show nonpatentability before the PTO may reject the claims of a patent application.’” Instead of following this law, the PTAB affirmed the obviousness rejections because “‘Rambus ha[d] not demonstrated that skilled artisans . . . would not have been able to arrive at the broadly claimed invention.’” According to the Federal Circuit, “That was legal error.”

Affirmance Versus New Ground Of Rejection

The Federal Circuit found that the PTAB erred by “supply[ing] its own reasons” to combine the cited prior art references.” As the court explained, once the PTAB had determined that the finding underlying the Examiner’s stated basis for combining the references “was erroneous” but identified other reasons for rejecting the claims, it should have followed the procedures “for issuing a new ground of rejection in appeals of inter partes reexaminations,” which would have given Rambus an opportunity to respond.

We cannot let the Board shortcut this procedure and deprive appellants of their due process rights.

Objective Evidence Of Nonobviousness

The Federal Circuit found that the PTAB erred in not giving sufficient weight to Rambus’ objective evidence of nonobviousness.

The court found that the PTAB had not addressed relevant evidence:

The Board erred when it found that Rambus’s objective evidence of nonobviousness lacked a nexus because it related to unclaimed features. Rambus presented uncontested evidence of long-felt need and industry praise due to the claimed dual-edge data transfer functionality claimed in the ’097 patent. …. The Board did not address any of this evidence.

The court found that the PTAB had been too strict in its requirement for “commensurate” evidence:

The Board also erroneously found that Rambus’s evidence relating to high-speed memory systems was not commensurate with the scope of the claims because the claims “do not recite a specific clock speed and therefore embrace slow memory devices.” …. Such a strict requirement was improper. Objective evidence of nonobviousness need only be “reasonably commensurate with the scope of the claims,” and we do not require a patentee to produce objective evidence of nonobviousness for every potential embodiment of the claim.

The court found that the PTAB overlooked objective evidence that related to the patented invention as a whole:

The Board’s finding that all of Rambus’s evidence lacked a nexus because dual-edge functionality was already disclosed in Inagaki, and therefore “not novel,” is also erroneous. …. While objective evidence of nonobviousness lacks a nexus if it exclusively relates to a feature that was “known in the prior art,” … the obviousness inquiry centers on whether “the claimed invention as a whole” would have been obvious, 35 U.S.C. § 103. Rambus’s objective evidence of nonobviousness was not limited to the dual-edge functionality in Inagaki that transferred a single bit each half-cycle of an external clock. …. At least some of Rambus’s objective evidence of nonobviousness pertained to Rambus’s overall memory device architecture. On remand, the Board should be careful to parse the evidence that relates only to the prior art functionality and the evidence that touted Rambus’s patented design as a whole.

The court therefore affirmed-in-part, vacated-in-part, and remanded the case back to the USPTO.

Improving The Quality Of USPTO Decisions

The USPTO must recognize that the quality of its decisions at all levels—from the examining corps to the PTAB—is essential to a strong patent system. As the number of ex parte and inter partes appeals pending before the PTAB is increasing on a daily basis, it is disturbing to see that the PTAB continues to make new grounds of rejection on appeal in the face of several recent Federal Circuit decisions highlighting the legal error and injustice of that “shortcut.” Perhaps the PTAB is trying to mitigate the consequences of examiner errors, but doing so not only deprives applicants of due process, it also misses an opportunity to improve examination quality by providing direct feedback from the PTAB to the examining corps.