Widely Asserted Patent Claim Held Invalid at USPTO

The Rambus patent portfolio is well known, if not notorious, in the semiconductor industry. Over the years, Rambus has aggressively pursued licensing deals with Infineon, Hynix, Samsung and others. More recently, Rambus has been on the offensive against industry stalwarts such as Broadcom, Freescale, LSI, MediaTek, nVidia and ST Micro. 

As with any high value patent disputes, concurrent patent reexamination proceedings have been initiated at the USPTO against the Rambus portfolio. While these proceedings have largely co-existed without greatly impacting the Rambus litigation juggernaut, that may change as appeal proceedings conclude at the USPTO. 

In a Board of Patent Appeals & Interferences (BPAI) decision today, a decision rejecting Rambus’ U.S. Patent 6,034,198 in view of certain prior art was affirmed.


<—Pending Rambus Patent Reexaminations as listed in Examiner Answer Brief  (click to enlarge)

In the appeal decision, (here), the BPAI found the examiner’s rejection of claim 18 of the ‘198 Patent supported by substantial evidence. (claims 24 and 33 were confirmed prior to appeal, no other claims of the ‘198 Patent were subject to patent reexamination)

At issue in the appeal is the meaning of the claim term “memory device.” Rambus argued that this term embraced  a single chip embodiment. The examiner found the terminology broad enough to embrace a memory stick embodiment of the ‘198 patent, and this could not be limited to a single chip.

To support their argument, Rambus submitted declaration evidence as to the meaning of “device” in the art. Interestingly, the USPTO cited to inconsistent deposition evidence submitted in a related Rambus patent reexamination. Rambus objected to the late introduction of this evidence in the Examiner Answer. Furthermore, Rambus argued that the deponent (a Hynix expert) was a hired gun, and was not at all commenting on the “memory device” issue. In response, the BPAI explained to Rambus that they should have read the Hynix documentation a bit closer. Footnote 6 of the BPAI decision, explains, in part :

. . . Appellant listed the underlying district court proceeding (No. 05-00334 RMW (N.D. Cal.)) and the merged reexamination proceeding (95/001,109 and 95/001,155) involving this deposition in the Brief, describing those proceedings as related to the instant proceeding. (App. Br. 1, 4.) Appellant’s Reply Brief also asserts that Hynix employed [deponent]  as an expert in several related reexamination proceedings, but “[deponent] has not offered an opinion on the construction of the term ‘memory device’ in those declarations.” (Reply Br. 14 n. 11). To the contrary, [deponent’s] declaration does include a definition (or two) for a “memory device.” This declaration appears in the same litigation and reexamination and was attached to the same Rambus response as the deposition. (See McA2.) By raising an asserted lack of a proffered definition in the Reply Brief after submitting the declaration showing otherwise in a related proceeding, even though the Examiner does not rely on the declaration, Rambus cannot complain of its use or claim surprise, whether used only to contradict the assertion made, or as substantive evidence. . .(emphasis added) 

The fight for the ‘198 Patent will certainly continue on the CAFC, or perhaps even the district court. Still, despite the final outcome, the ‘198 Patent will maintain all other claims— presumably, confirmed claims 24 and 33 are commercially valuable. Nevertheless, as the Rambus patent reexaminations mature, the USPTO will likely continue to chip away at the Rambus arsenal.