On February 8, 2019, the U.S. Court of Appeals for the Federal Circuit (“Federal Circuit”) decided Continental Circuits LLC v. Intel Corporation, holding an embodiment of a patent specification cannot limit the claims without express disavowal of claim scope or where the patent specification did not make clear that the limitation was an essential part of the claimed invention.
Continental Circuits LLC (“Continental”) owns several U.S. continuation patents, one of which was U.S. Patent No. 8,581,105 (“the ”²105 patent”). The patents are directed to a “multilayer electrical device…having a tooth structure.” Continental sued Intel Corporation (“Intel”) for patent infringement in the U.S. District Court of Arizona (“district court”), asserting several claims from each patent. Each claim included limitations regarding the “surface,” “removal,” or “etching” of “a dielectric material” or “epoxy.”
At trial, the district court first found the patent specification repeatedly distinguished the process covered by the ”²105 patent from the prior art and its use of a single desmear process, in addition to characterizing the present invention as using a repeated desmear process. Furthermore, the district court found that the expert declaration used to overcome an indefiniteness rejection clearly described a process that involved a two etching process. Accordingly, the district court found that Continental clearly limited the ”²105 claims to being “produced by a repeated desmear process.” Subsequently, Continental appealed.
On appeal, the Federal Circuit found that the district court erred in limiting the claims to require a “repeated desmear process.” First, the Federal Circuit noted that although the patent specification disclosed a repeated desmear process, without clear indication in the specification, the claim terms should not be limited to a disclosed embodiment. The Federal Circuit found that the phrases, “for example,” “one technique…is the double desmear process,” and “the present invention can be carried out,” demonstrated that the ”²105 patent claims could be carried out by different processes. Moreover, the patent specification did not state that the “repeated desmear process” was an essential part of the claimed invention. Therefore, there was not clear and unmistakable indication that the claims should be limited to a “repeated desmear process.
Furthermore, the Federal Circuit found that there was no clear disavowal of claim scope in the prosecution history. Although the expert declaration Continental submitted to overcome the indefiniteness rejection only discussed a repeated desmear process, the Federal Circuit stated “describing a particular claim term to overcome an indefiniteness or written description rejection is not the same as clearly disavowing claim scope. The Federal Circuit went on to say that the expert merely explained one technique for performing the claimed process and did not intend to limit the claims to that technique.
Therefore, the Federal Circuit concluded that because the patent specification and prosecution history did not limit the claims to a “repeated desmear process,” a consideration of extrinsic evidence was not needed. Accordingly, the Federal Circuit vacated the district court decision, finding an embodiment discussed in the patent specification cannot limit a claim without clear and unmistakable intent by the patentee.