Nicolas Seckel | August 29, 2012
Greenliant Systems, Inc. v. Xicor LLC
August 22, 2012
Panel: Linn, Plager and Dyk. Opinion by Dyk
Xicor obtained a patent claiming a semiconductor device with a tunneling layer formed by low pressure chemical vapor (CVD) deposition using tetraethylorthosilicate (TEOS). Xicor sought and obtained reissue of the patent with device claims that did not recite the use of TEOS. Subsequently, Greenliant sued Xicor for declaratory judgment of invalidity of the reissue claims based on recapture rule, which prohibits recapture via reissue of subject matter surrendered in order to overcome prior art during prosecution of the original patent. The District Court held the reissue claims invalid, and the Federal Circuit affirms. Xicor had repeatedly argued during prosecution of the original patent that the product-by-process limitation of using TEOS imparted structural limitations to the final product. This is sufficient for the recapture rule to apply, even if Xicor now recognizes that the structure of the tunneling layer does not actually depend on the material used for the CVD process, but on deposition conditions such as temperature and pressure.
Xicor had initially filed a patent application claiming a method for depositing an electron tunneling layer by low pressure chemical vapor deposition (CVD), and a device containing such a deposited tunneling layer. The examiner sent a restriction requirement, and Xicor elected the method claims. The examiner rejected the claims as obvious over prior art disclosing the use of low pressure CVD, but indicated that claims reciting the use of tetraorthosilicate (TEOS) would be allowable. Xicor amended the method claims accordingly, and a first patent issued.
Before issuance of the method patent, Xicor filed a divisional application for the original device claim and additional device claims. All the independent device claims recited that the tunneling layer is “formed by low pressure chemical vapor deposition.” The examiner rejected the device claims as obvious. In response, Xicor amended the claims to additionally recite “comprising the use of tetraethylorthosilicate.” Xicor proceeded to argue forcefully before the examiner, then the Board of Appeals, that the TEOS limitation imparts structural differences that distinguish the claimed tunneling layer over the cited art, including an increase of the total charge that can be conducted and a lower stress level in the material. The Board reversed the examiner’s rejection and a patent issued on Xicor’s divisional application.
Within two years of issuance of its device patent, Xicor filed a reissue application adding new device claims that did not recite the “comprising the use of TEOS” limitation. The reissue examiner found that the claims were not broader than the surrendered subject matter” and a reissue patent issued with the new claims.
A dispute arose between Xicor and Greenliant, and Greenliant filed a declaratory judgment action against Xicor seeking a declaration of invalidity of the reissued claims under the recapture rule.
35 U.S.C. 251 provides that a patentee may surrender a patent and seek reissue enlarging the scope of the original patent claims if, “through error without any deceptive intention” (note: the lack of deceptive intent requirement is removed by the American Invents Act effective Sep 16, 2012), the original patent claimed “less than [the patentee] had a right to claim in the patent.” However, under the “recapture rule,” a patentee cannot regain through reissue subject matter that was “surrendered in an effort to obtain allowance of the original claims.” Surrender can occur through amendment or through argument during prosecution, if the patentee “clearly and unmistakably argue that his invention does not cover subject matter to overcome an examiner’s rejection based on prior art.”
Here Xicor argues that its argument about the structural effect of using TEOS could not have been effective to overcome prior art because, as a technical matter, the structure of the tunneling layer does not actually depend on the material used for the CVD process, but on deposition conditions such as temperature and pressure. According to Xicor, since the TEOS process limitation does not actually impart structural differences in the tunneling layer, the TEOS limitation could not have been the basis for allowance of the predecessor patent claims. The Federal Circuit holds that this aspect is irrelevant, because the rule against recapture is triggered, not by the USPTO’s reasons for allowance, but by the fact that the applicant made a certain argument.
The Court draws an analogy with its case law on prosecution history estoppel, which prevents application of the doctrine of equivalents to subject matter that was clearly and unmistakably surrendered through a narrowing amendment or an argument during prosecution.
Takeaway: This case is another reminder that every argument made by the applicant during prosecution of a patent application counts. Even ineffective, superfluous, or technically incorrect arguments can trigger, not only a loss of equivalent scope under prosecution history estoppel, but also a bar against obtaining broader claims via reissue under the recapture rule, if the argument is found to have surrendered subject matter in an effort to obtain allowance of the original patent.