In Continental Circuits LLC v. Intel Corporation, No. 2018-1076 (Fed. Cir. Feb. 8, 2019), a Federal Circuit panel confirmed that disavowal of claim scope, whether in the patent’s specification or prosecution history, must be “clear and unmistakable.”

The patents at issue in Continental Circuits were directed to “a multilayer electrical device . . . having a tooth structure” and “methods for making the same,” where the “teeth improve[d] the adhesion of the layers to one another.”  Continental Circuits, slip op. at 2-3.  The specification disclosed that “[o]ne technique for forming the teeth is . . . the swell and etch or desmear process,” where plasma treatment removes residue created from drilling holes in the circuit board.  Id. at 3 (alterations in original).

The district court construed claim terms regarding the “surface,” “removal,” or “etching” of “a dielectric material” or “epoxy,” to require a repeated desmear process.  Id. at 7.  Specifically, the district court found that the patentee had disclaimed a broader scope because “the specification not only ‘repeatedly distinguishe[d] the process covered by the patent from the prior art and its use of a ‘single desmear process,’’ but also characterized ‘the present invention’ as using a repeated desmear process.”  Id. (alterations in original) (citations omitted).  The district court also found that the prosecution history corroborated its construction.  Id.

The Federal Circuit reversed, holding that “the district court erred in limiting the claims to require a repeated desmear process” as it improperly imported a limitation from the specification into the claims.  Id. at 10.  Specifically:

  • the plain language of the claims did not recite a “repeated desmear process” and thus did not limit the claims to a repeated desmear process (id. at 11);
  • “none of the statements [in the specification] relied upon by the district court [rose] to the level of a ‘clear and unmistakable disclaimer’” (id. at 12 (quoting Thorner v. Sony Computer Entertainment America, LLC, 669 F.3d 1362, 1367 (Fed. Cir. 2012))), as they “simply describe[d] how to make the claimed invention using the preferred [instrument] in a ‘new’ way that is different from the prior art process and [were] not statements clearly limiting the claimed ‘electrical device’ to require a repeated desmear process” ( at 13); and
  • “the cited statements in the prosecution history [did] not clearly and unmistakably disavow any claim scope” as “clearly describing a particular claim term to overcome an indefiniteness or written description ejection [was] not the same as clearly disavowing claim scope” (id. at 15).

“Thus, absent ‘clear and unmistakable’ language suggesting otherwise,” the Federal Circuit “conclude[d] that the aforementioned statements [did] not meet the ‘exacting’ standard required to limit the scope of the claims to a repeated desmear process.”  Id. at 15 (citing Thorner, 669 F.3d at 1366-67).

The decision here reiterated that any disclaimer must be clear and unmistakable.  However, other Federal Circuit decisions have held that such a disclaimer may still be implicit, meaning “clear and unmistakable” is not without gray area.  See, e.g.Poly-America, L.P. v API Indus., Inc., No. 2016-1200 (Fed. Cir.  Oct. 14, 2016).  Likewise, the intrinsic evidence may narrow a claim term even without disclaimer.  See, e.g.,  Aptalis Pharmatech, Inc. v Apotex Inc., No. 2017-1344 (Fed. Cir. Jan. 4, 2018) (nonprecedential).

With IPR, PGR, and CBM petitions filed on or after November 13, 2018 being governed by the Phillips standard—such that Federal Circuit decisions applying Phillips are squarely controlling—Patent Owners wishing to rely on a disclaimer should be especially vigilant that any arguments for a disclaimer are not only strictly supported by the prosecution history, but also by expert testimony on how a person of ordinary skill in the art (POSITA) would have understood that prosecution history, and documentary evidence showing the context—e.g., state of the art—that would have driven that understanding.