Board Exceeded Its 'Limited Role' In Reviewing Examiner’s Findings During Reexamination

In Rambus Inc. v. Rea, No. 12-1634 (Fed. Cir. Sept. 24, 2013), the Federal Circuit reviewed an invalidity decision made by the Board during reexamination proceedings. The Court affirmed the Board's claim construction, vacated the Board's obviousness decision, and remanded for further proceedings.

U.S. Patent No. 6,260,097 ("the '097 patent") is directed to a dynamic random-access memory ("DRAM") that uses a synchronous memory system to transfer data. In synchronous systems, a clock signal alternates between a digital value of 0 and 1. The change in the clock signal from 0 to 1 is referred to as the "rising edge" of the clock, and the change in the signal from 1 to 0 is referred to as the "falling edge" of the clock. In conventional synchronous memory systems, the data transmitted to the memory tie up the system for a full cycle of the clock. The '097 patent is directed to a system that transfers a portion of the data on the rising edge and a portion of the data on the falling edge of the clock signal, transferring data at twice the rate.

The PTO initiated inter partes reexamination of the '097 patent claims and found that the reexamined claims were not patentable over two references: Unexamined Japanese Patent Application No. 56-88987 ("Inagaki") and the Intel iAPX system manual and specification ("iAPX"). The examiner rejected the claims as anticipated by Inagaki and/or obvious in light of the iAPX system in view of Inagaki. The Board upheld the examiner's rejections, and Rambus appealed.

Regarding anticipation, the Federal Circuit first considered whether the Board properly construed "external clock signal" as requiring the clock to be periodic during the data input phases, as opposed to being periodic for all system operations. Rambus contended that the intrinsic record required the "external clock signal" to be continuously periodic. The PTO countered that the claim language required only that the external clock signal synchronize data transfer and need not be periodic for all time. The Federal Circuit agreed with the PTO that the claimed method required that the "external clock signal" be periodic during data transfer, but that nothing in the claim language, specification, or prosecution history required the signal to be periodic for all time.

"The Board has a procedure for issuing a new ground of rejection in appeals of inter partes reexaminations. 37 C.F.R. § 41.77(b). This procedure ensures that appellants have an appropriate...