Federal Circuit Confirms “Known-Technique” Rationale as an Indicator of a Motivation to CombineMarch 15, 2023

In KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 419 (2007) (“KSR”) the U.S. Supreme Court criticized rigid application of the so-called “teaching, suggestion, or motivation” test (“the TSM test”) which, prior to KSR, had often been applied by courts when determining obviousness of patent claims. Under the TSM test, “a patent claim is only proved obvious if ‘some motivation or suggestion to combine the prior art teachings’ can be found in the prior art, the nature of the problem, or the knowledge of a person having ordinary skill in the art.” KSR, 550 U.S. at 407 (citing Al–Site Corp. v. VSI Int’l, Inc., 174 F.3d 1308, 1323–1324 (C.A.Fed.1999)). Post-KSR, the TSM test is not the definitive test used to assess obviousness of patent claims. Rather, the KSR court provided additional guidance as to how to evaluate obviousness noting that analysis used to render patent claims obvious “should be made explicit.” Id. at 418. The KSR court quoted In re Kahn, 441 F.3d 977, 988 (C.A.Fed. 2006) noting that “rejections on obviousness grounds cannot be sustained by mere conclusory statements; instead, there must be some articulated reasoning with some rational underpinning to support the legal conclusion of obviousness.” KSR, 550 U.S. at 418. Further, the Manual of Patent Examining Procedure (“MPEP”) provides that when making an obviousness rejection under 35 U.S.C. § 103, a patent examiner should provide in the Office action “an explanation as to why the claimed invention would have been obvious to one of ordinary skill in the art at the time the invention was made.” MPEP 2142. Accordingly, in instances when a patent examiner rejects a patent claim as obvious under 35 U.S.C. § 103 wherein the rejection is based on a combination of multiple prior art references, patent applicants often argue that there is no motivation to combine the references based on the knowledge of one skilled in the art at the time the invention was made.

For example, in March of 2023 in Intel Corp. v. PACT XPP Schweiz AG, (“Intel v. PACT”), the Court of Appeals for the Federal Circuit (“Federal Circuit”) reversed an inter partes review (“IPR”) decision by the Patent Trial and Appeal Board (“PTAB”) wherein the PTAB had held that Intel Corp. (“Intel”) failed to show that the challenged claims of U.S. Pat. No. 9,250,908 (“the ‘908 patent”) were unpatentable as obvious. At issue during the IPR and on appeal, was whether there was sufficient motivation to combine the prior art references asserted to invalidate the challenged claims of the ‘908 patent. On appeal, the Federal Circuit expounded upon the motivation to combine inquiry.

The ’908 patent, the patent at issue in Intel v. PACT, is owned by PACT XPP Schweiz AG (“PACT”) and is directed to “multiprocessor systems and how processors in those systems access data.” Multiprocessor systems typically store data via a main memory as well as different cache memories. While the use of cache memories can provide quick access to data, issues can arise related to cache coherency. For instance, different caches can have different local copies of data and inconsistencies in such data can arise when a change of data occurs on one cache which is not propagated to the other caches. Thus, multiprocessor systems “often require a mechanism to monitor and maintain cache coherency.”

Intel petitioned for institution of an IPR challenging claims 4 and 5 of the ‘908 patent, however, the IPR proceeding and subsequent appeal to the Federal Circuit focused only on claim 4. In its petition, Intel argued that a combination of two prior art references, U.S. Pat. No. 5,890,217 (“Kabemoto”) and U.S. Pat. No. 5,680,571 (“Bauman”), rendered the challenged claims unpatentable as obvious. The PTAB concluded that the prior art combination did not teach each element of challenged claim 4, and, additionally, the PTAB further concluded that “Intel failed to show that a person of ordinary skill in the art would have been motivated to combine the teachings of Kabemoto and Bauman.” Intel appealed the PTAB’s decision to the Federal Circuit.

On appeal, Intel argued that the PTAB erred in determining that the prior art combination failed to teach an element of challenged claim 4 and further that the PTAB erred in determining that there was no motivation to combine the asserted prior art references. In its decision, the Federal Circuit first addressed the issue of whether the prior art combination taught the disputed element of challenged claim 4. On that issue, the Federal Circuit reversed the PTAB’s conclusion, and held that the prior art combination did indeed teach the disputed element.

The Federal Circuit then focused on the issue of whether a motivation to combine the prior art references existed. The Federal Circuit first quoted KSR, noting that “any need or problem known in the field of endeavor at the time of invention and addressed by the patent can provide a reason for combining the elements in the manner claimed.” KSR, 550 U.S. at 420 (emphasis added). Additionally, “[a] person of ordinary skill is also a person of ordinary creativity, not an automaton.” Id. at 421. Further, “the motivation-to-combine analysis ‘need not seek out precise teachings directed to the specific subject matter of the challenged claim, for a court can take account of the inferences and creative steps that a person of ordinary skill in the art would employ.’” Id. at 418. The court further noted that “‘universal’ motivations known in a particular field to improve technology provide ‘a motivation to combine prior art references even absent any hint of suggestion in the references themselves.’” Intel Corp. v. Qualcomm Inc., 21 F.4th 784, 797 (Fed. Cir. 2021).

Intel argued that a motivation to combine existed based on the so-called “known-technique” rationale. The KSR court characterized the “known-technique” rationale by holding “if a technique has been used to improve one device, and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way, using the technique is obvious unless its actual application is beyond his or her skill.” KSR, 550 U.S. at 417. The Federal Circuit further noted that “if there’s a known technique to address a known problem using ‘prior art elements according to their established functions,’ then there is a motivation to combine.” Intel Corp. v. Qualcomm Inc., 21 F.4th at 799–800. Additionally, the Federal Circuit noted that in order for a motivation to combine prior art references to exist, the combination need only be a suitable option to address a known problem. There is no requirement for the combination to be the best option.

During the IPR proceedings, Intel argued that a motivation to combine the asserted prior art references existed because the references “‘relate to the same field of multiprocessor . . . systems’ and ‘address the same problem: maintaining cache coherency.’” Intel further argued that a person of ordinary skill in the art “‘would have naturally turned to Bauman’s [cache technique] to use . . . in Kabemoto’ since Bauman’s [cache technique] was known to address the same cache-coherency issue that Kabemoto also sought to address, just through a different mechanism.” Thus, Intel’s argument employed the “known-technique” rationale.

The PTAB rejected Intel’s “known-technique” argument, noting that if Kabemoto and Bauman address the same problem, namely cache coherency, via the use of a known similar technique, then one of ordinary skill in the art would not look to Bauman’s technique as an obvious improvement to Kabemoto. On appeal, the Federal Circuit disagreed with the PTAB noting that the fact that the two prior art references address the same problem and that Bauman’s technique is a known way to address the problem “is precisely the reason that there’s a motivation to combine.” The Federal Circuit continued, holding that:

[t]here is a motivation to combine when a known technique “has been used to improve one device, and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way,” KSR, 550 U.S. at 417, using the “prior art elements according to their established functions,” Intel, 21 F.4th at 799–800.

The Federal Circuit further noted that there was no dispute as to the fact that Bauman’s technique had been used in the art to improve the problem (i.e., cache coherency), nor was there a dispute as to the fact that a person of ordinary skill in the art would recognize that Bauman’s technique would improve a similar device (e.g., Kabemoto) by addressing the same problem. Further, the Federal Circuit noted that there was no dispute as to the fact that Bauman’s technique would be used according to its established function if combined with another multiprocessor system to solve the cache coherency problem. The Federal Circuit concluded its discussion of the issue of motivation to combine by holding that Intel met the requirements to show a motivation to combine by showing there was a known problem in the art (i.e., cache coherency), that Bauman’s technique helped address the problem, and that combining Kabemoto and Bauman was not “beyond the skill of an ordinary artisan.” The Federal Circuit noted that nothing more is needed in order to show a motivation to combine. For example, there was no need for Intel to show that substituting Kabemoto’s cache technique for Bauman’s cache technique constituted an “improvement.” Rather, Intel only had to demonstrate that Bauman’s cache technique was a suitable option to replace Kabemoto’s cache technique. Thus, the Federal Circuit reversed the PTAB’s decision of a lack of motivation to combine the asserted prior art references. The case was also remanded to address patentability of claim 5 of the ‘908 patent which was not addressed by the PTAB or the Federal Circuit.

As evidenced by Intel v. PACT, in order to invalidate patent claims as unpatentable for obviousness, parties often argue about motivation, or lack thereof, to combine prior art references. Intel v. PACT serves to affirm the “known-technique” rationale as a viable method to show a motivation to combine while also expounding on the details of the motivation to combine inquiry.

Joseph M. Hallman is a Patent Attorney in the Mechanical and Electrical Patent Practice Group at McKee, Voorhees & Sease, PLC. For additional information please visit www.ipmvs.com or contact Joseph directly via email at joseph.hallman@ipmvs.com.