925 F.3d 1373
Fed. Cir.2019Background
- Elm 3DS owns eleven related patents covering stacked integrated-circuit memory; Samsung, Micron, and SK Hynix (Petitioners) sought inter partes review (IPR) of 105 claims across those patents.
- Petitioners’ obviousness grounds relied primarily on Bertin or Yu combined with Leedy (which teaches low-stress silicon-based dielectrics); many claims require a “substantially flexible” substrate or circuit layer and/or a low-tensile-stress dielectric.
- The PTAB held Petitioners failed to prove unpatentability, finding (1) prior art did not disclose the “substantially flexible” limitation as claimed and (2) Petitioners failed to show a motivation to combine Bertin/Yu with Leedy or a reasonable expectation of success.
- Key factual dispute: whether substituting Leedy’s low-stress dielectric (deposited by PECVD) for Bertin/Yu’s thermally-grown dielectric would have been compatible with the rest of Bertin/Yu fabrication processes and produce the claimed low-stress, substantially flexible layers.
- The Board credited Elm’s expert (Dr. Glew) that PECVD dielectrics differ materially from thermally-grown oxides (purity, contamination, plasma damage, process timing), so a skilled artisan would not have reasonably expected success in the proposed combinations.
- The Federal Circuit affirmed, construing “substantially flexible” to require (a) a semiconductor substrate thinned to ≤50 µm and polished/smoothed such that it can largely bend without breaking, and (b) for a substantially flexible circuit layer, inclusion of such a substrate plus a sufficiently low tensile-stress dielectric.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Proper construction of “substantially flexible” | Petitioners: means any substrate thinned to <50 µm and polished/smoothed (per spec step 2A) | Elm: ordinary meaning (“largely able to bend without breaking”); prosecution history narrows term | Court: hybrid — term requires thinning to ≤50 µm and polishing/smoothing such that substrate is largely able to bend without breaking; circuit layer also requires low-tensile-stress dielectric |
| Motivation to combine Leedy with Bertin/Yu | Petitioners: Leedy’s PECVD dielectrics are in same technological field and could replace Bertin/Yu dielectrics predictably | Elm: PECVD/Leedy dielectrics are materially different (purity, plasma ions, process temps); incompatibility undermines motivation | Court: Board’s finding of lack of motivation supported; Petitioners didn’t show how fabrication would be changed to use Leedy’s dielectric |
| Reasonable expectation of success in combining references | Petitioners: routine substitution; Leedy incorporated by reference in Elm’s patents supports triviality | Elm: expert showed many material factors (purity, stress, adhesion, process phase) make success uncertain | Court: substantial evidence supports Board’s finding of no reasonable expectation of success; dispositive for all challenged claims requiring low-stress dielectrics |
| Whether Board improperly required physical combinability evidence | Petitioners: Board demanded proof of combining unclaimed elements | Elm/Board: complexity of IC fabrication warrants specific evidence of feasibility | Court: Board did not err — it appropriately required evidence showing a skilled artisan would have reasonably expected success in the combination |
Key Cases Cited
- Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir.) (claim construction principles)
- Aventis Pharma S.A. v. Hospira, Inc., 675 F.3d 1324 (Fed. Cir.) (ordinary meaning and intrinsic evidence govern claim construction)
- In re CSB-Systems Int’l, Inc., 832 F.3d 1335 (Fed. Cir.) (claim construction standard for expired patents)
- Belden Inc. v. Berk-Tek LLC, 805 F.3d 1064 (Fed. Cir.) (obviousness review: legal conclusions de novo, factual findings for substantial evidence)
- Intelligent Bio-Sys., Inc. v. Illumina Cambridge Ltd., 821 F.3d 1359 (Fed. Cir.) (motivation to combine and reasonable expectation of success are factual)
- In re Mouttet, 686 F.3d 1322 (Fed. Cir.) (no physical substitution required where references teach combination)
- In re Applied Materials, Inc., 692 F.3d 1289 (Fed. Cir.) (agency findings may be supported even where evidence permits differing inferences)
- SightSound Techs., LLC v. Apple Inc., 809 F.3d 1307 (Fed. Cir.) (consistent claim interpretation across related patents)