Addressing whether, in a broadening reissue application, a patentee can remove claimed features that were relied upon during prosecution of the parent patent to distinguish prior art, the U.S. Court of Appeals for the Federal Circuit found that a patentee cannot use a reissue to broaden a claim to include subject matter that was intentionally disclaimed during prosecution of the parent patent for purposes of having the parent patent granted.  Greenliant Systems, Inc. v. Xicor LLC, Case No. 11-1514 (Fed. Cir., Aug. 22, 2012) (Dyk, J.).

Xicor filed a parent patent application for a device containing a deposited electron tunnel layer.  During prosecution, Xicor amended the independent claims to require the use of tetraethyl orthosilicate (TEOS) and argued that using TEOS to form the electron tunnel layer was the feature that distinguished the claimed invention from the prior art.

Subsequently, Xicor filed a reissue application, which excluded the use of TEOS that was claimed in the parent patent.  The examiner found that the reissue claims “did not include and were not broader than the surrendered subject matter, and thus were not barred by the recapture rule,” and the reissue patent issued.  Later, a dispute arose between Xicor and Greenliant, and Greenliant sought to invalidate the reissue patent under the recapture rule.

The recapture rule states that a patentee cannot regain through reissue subject matter that he or she surrendered in order to obtain allowance of the original claims.  Here, Xicor argued that the TEOS features could not have been effective in overcoming the prior art, and, therefore, Xicor did not surrender non-TEOS implementations because the structure of the tunneling layer does not depend on the material used for the process but depends on conditions present during the process, such as temperature and pressure. 

The Federal Circuit rejected Xicor’s arguments explaining, “Xicor is bound by the arguments that it made before the examiner … the sole question is whether the argument was made,” not whether the argument was technologically accurate.  Thus, Xicor could not obtain a reissue patent that did not include the TEOS features because Xicor explicitly relied on the TEOS features to obtain the parent patent.

The Federal Circuit likened reissue recapture to prosecution history estoppel.  Under prosecution history estoppel, a patentee who surrenders subject matter during prosecution of a patent cannot later reclaim the surrendered subject matter under the doctrine of equivalents.  Similarly, under reissue recapture, a patentee who surrenders subject matter during prosecution of a parent case cannot later reclaim the surrendered subject matter in a reissue application.