Opinion ID: 806686
Heading Depth: 3
Heading Rank: 1

Heading: Single Chip Limitation

Text: Rambus relies on language from the specification, expert testimony, and the prosecution history of the ’918 Patent to support its argument that a “memory device” must be a single chip device.
Rambus points to portions of the specification where “memory device” refers to a single chip component. ’918 Patent col. 17 ll. 14-27, col. 3 ll. 61-63. Rambus then cites Lisle Corp. v. A.J. Manufacturing, 298 F.3d 1306, 1314 (Fed. Cir. 2005), and argues that the stated goals of the invention could be achieved only through a single chip memory device. Finally, Rambus disagrees with the weight the Board afforded the “memory stick” embodiment disclosed in the specification. According to Rambus, the disclosure of the memory stick as an alternative to a memory device shows that they are two distinct embodiments. The PTO concedes that the ’918 Patent specification uses the term memory device to describe single chip embodiments of the invention, but stresses that nothing in the specification limits the invention to such devices. The PTO agrees with the Board that the multichip memIN RE RAMBUS 9 ory stick embodiment disclosed in the specification is an example of a memory device and posits that this embodiment proves these devices can consist of more than one chip. This court agrees with the Board that the specification does not restrict the invention to single chip memory devices. There are no words of manifest exclusion or clear disavowals of multichip devices—there are only preferred embodiments and goals of the invention that Rambus argues are better met by single chip devices. The specification language Rambus cites shows only that the invention can be carried out with a single chip memory device, it does not require the invention to be so performed. ’918 Patent col. 17 ll. 17-27 (referring to an embodiment where a single RAM supplies all bits for a block request). Other portions of the specification that Rambus cites are completely inapposite to the determination of the number of chips in a memory device. Rambus stresses that the invention allows “high-speed access to large blocks of data from a single memory device.” Appellant’s Br. 27 (emphasis in original). But this in no way indicates that the single memory device must be made of a single memory chip. Rambus has not demonstrated that a “memory device” is a term of art, and nothing indicates these other “devices” are limited to single chips. To the extent Rambus wanted to limit the memory device to a single chip component, it could have expressly done so. It did not, and this court will not do so here. The Board’s equating the multichip “memory stick” with a “memory device” to support its conclusion that the memory device is not limited to a single chip is, however, incorrect. The specification could not be clearer that the disclosed invention can be practiced with either a memory device or with a memory stick. ’918 Patent col. 20 ll. 5-8. While the Board was incorrect that a memory device and 10 IN RE RAMBUS memory stick are the same, this does not mean that a memory device must contain only one chip.
Rambus cites testimony previously made on Hynix’s behalf, which suggests a memory device is made of a single chip. Rambus also points to a joint-stipulation it previously made with Hynix during district court litigation. There the parties agreed that “memory device” in a related patent meant “an integrated circuit device in which information [could] be stored and retrieved electronically.” Joint Claim Construction and Prehearing Statement at 1 Hynix Semiconductor Inc. v. Rambus, Inc., No. 00-20905 (N.D. Ca.). This court previously construed “integrated circuit device” as a single chip. Rambus v. Infineon Techs. Ag, 318 F.3d 1081, 1091 (Fed. Cir. 2003). Thus, Rambus urges us to conclude that a skilled artisan would interpret “memory device” as a single chip component. The PTO counters that claim 18 of the ’918 Patent is directed to broad subject matter and “memory” is more accurately read as an adjective modifying “device.” The PTO argues that the plain language of the claim does not restrict “memory devices” to single chip components and that the word “device” is broad enough to cover any component for carrying out the memory functions of a computer. We agree with the PTO. With respect to the meaning of the term “memory device,” the expert testimony on which Rambus relies directly conflicts with the testimony on which the Board relies. The Board cites to Hynix where Hynix’s expert specifically described how a memory device might consist of more than one chip. In contrast, Rambus stresses the joint stipulation in Hynix where Hynix agreed to define a memory device as an integrated IN RE RAMBUS 11 circuit device, and Hynix’s expert Desi Rhoden’s (“Rhoden”) unrelated interference testimony that a memory device is “typically not” a card with multiple memory chips on it. According to Rambus, these are instances where even its adversary recognized that a “memory device” is understood to be a single chip component. But Rhoden’s testimony stated only that a card with multiple package memory chips on it is typically not a memory device. She did not say that a memory device must be made of a single chip. Ultimately, the expert testimony is conflicting and unpersuasive.
Rambus argues that it distinguished U.S. Patent No. 4,315,308 (“Jackson”) during prosecution of the ’918 Patent based on the number of chips in a memory device. The PTO counters that the distinctions Rambus drew to overcome Jackson did not limit the term to a single chip. According to the PTO, Rambus distinguished Jackson on other grounds. The PTO is correct; Rambus distinguished Jackson during prosecution on the basis that the “memory device” of the ’918 Patent did not perform the functions performed by Jackson’s BIU—an argument we analyze in more detail, infra, in connection with the “memory controller” issue. The PTO also asserts a claim differentiation argument, directing the court to other patents in the ’898 family where Rambus used the term “memory device” in some claims but specifically claimed single chip components in others. The parties agree that “unless otherwise compelled . . . the same claim term in the same patent or related patents carries the same construed meaning.” Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1334 (Fed. Cir. 2003). In related U.S. Patent No. 5,638,334 (“’334 Patent) independent claim 1 recites a “memory 12 IN RE RAMBUS device” while dependent claim 6 covers memory devices “formed on a single semiconductor substrate.” Compare ’334 Patent col. 25 ll. 2-17, with ’334 Patent col. 26 ll. 1-2. Rambus argues that because dependent claim 6 adds the limitation that the substrate be a semiconductor, the word single does not necessarily limit the term “memory device,” which, according to Rambus, already indicates a single chip. But if a memory device were always a single chip there would be no need to use the word “single” in claim 6, but not claim 1, regardless of any limitation regarding the substrate. Similarly, claim 1 of related U.S. Patent No. 5,954,804 (“’804 Patent”) refers to a memory device, and claim 15 refers to an “integrated circuit device” with a “plurality of memory cells” (i.e., a single chip). Compare ’804 Patent col. 24 l. 43, with ’804 Patent col. 25 l. 62. See also Infineon, 318 F.3d at 1091; Appellant’s Br. at 22. In sum, “memory device” is a broad term which has been used consistently in the ’918 patent and in the family of patents related to it to encompass a device having one or more chips. Moreover, and consistent with the district court’s opinion in Micron, there is no basis to find a disavowal or redefinition that would limit the term “memory device” to a single chip.