The US Court of Appeals for the Federal Circuit affirmed a Patent Trial and Appeal Board (PTAB) non-obviousness determination because substantial evidence supported the PTAB’s finding that a person of skill in the art would not have been motivated to combine two prior art references and would not have had a reasonable expectation of success in doing so because their disclosed technologies were incompatible. Samsung Electronics Co., Ltd. v. Elm 3DS Innovations, LLC, Case No. 17-2474, -2475, -2476, -2478, -2479, -2480, -2482, -2483, 18-1050, -1079, -1080, -1081, -1082 (Fed. Cir. June 12, 2019) (Moore, J).

Elm 3DS owns 11 patents that share a common specification and relate to “stacked integrated circuit memory.” The PTAB instituted inter partes review based on 13 petitions filed by Samsung, Micro and SK Hynix. The petitions challenged almost 105 patent claims as obvious based on either the Bertin patent or the Yu article as the primary reference in combination with the Leedy patent. After trial, the PTAB found the claims non-obvious because petitioners had not demonstrated a motivation to combine Bertin or Yu with Leedy, or a reasonable expectation of success in doing so. The petitioners appealed.

The Federal Circuit affirmed the PTAB’s obviousness findings. Beginning with the Bertin-Leedy combination, the petition had proposed depositing a low-stress dielectric material using plasma-enhanced chemical vapor deposition (PECVD), as disclosed in Leedy, instead of growing the dielectric layer, as disclosed in Bertin. Crediting Elm’s expert’s testimony that PECVD was incompatible with Bertin’s integrated circuit, the PTAB had found that a person of ordinary skill in the art would not have been motivated to combine Leedy with Bertin and would not have had a reasonable expectation of success in doing so. The Federal Circuit found that the PTAB’s finding was supported by substantial evidence since the petitioners did not adequately explain how Bertin’s fabrication process would be changed to use Leedy’s dielectric material, and found that the evidence showed that selecting a dielectric and a method of forming that dielectric was more complicated than the petitioners suggested, since dielectrics may have vastly different characteristics based on how they are made.

The petitioners also argued that the PTAB improperly required proof that unclaimed elements were combinable. The Federal Circuit found that the PTAB did not require unclaimed elements to be combinable, but instead had stated that integrated-circuit technology is complex and thus looked for specific evidence that a person of ordinary skill in the art would have reasonably expected success in combining Bertin’s fabrication process and Leedy’s dielectric material. The PTAB ultimately determined that the petitioners’ evidence in support combining Bertin and Leedy was insufficient, and the Court found no error in this finding.

Turning to the Yu-Leedy combination, the Federal Circuit noted that the arguments were substantially similar to those of the Bertin-Leedy combination. According to the petition, it would have been obvious to replace Yu’s silicon dioxide and processes for forming it with the dielectric and deposition process taught by Leedy. Elm’s expert testified that Yu identified its dielectric as a “field oxide,” which one of ordinary skill in the art would have understood is a highly pure dielectric grown directly on the silicon substrate at high temperatures using thermal oxidation. He further explained that a person of ordinary skill in the art would not have reasonably expected success using PECVD to deposit Leedy’s dielectric for the same reasons a person of skill in the art would not have used PECVD to deposit Leedy’s dielectric on the integrated circuit disclosed in Bertin. Accordingly, the Court found that the PTAB’s non-obviousness finding was supported by substantial evidence.