Northern California Judge invalidates claims in Xicor patent

A drawing from U.S. Patent RE38,370

Last Tuesday in San Francisco District Court Judge Marilyn Hall Patel found that two claims in Xicor's patent for tunneling an oxide layer between two conducting layers in a computer chip rendering that part of the patent unenforceable.

Silicon Storage Technology, Inc. (SST) filed a declaratory judgment action against Xicor, LLC (Xicor) seeking a declaration that claims 12 and 13 of U.S. Patent number RE38,370 were invalid under the rule against recapture.  Judge Patel explained:

“Under the rule against recapture, a patentee’s reissue claims are invalid when the patentee broadens the scope of a claim in reissue to cover subject matter that he surrendered during the prosecution of the original claims.” [MBO Laboratories v. Becton, Dickson & Co., (Fed. Cir. 2010).]

Here, the original claims identified tetraethylorthosilicate (TEOS) as the preferred chemical for the low temperature chemical vapor deposition  process which patently increases the useful life cycle of electrically erasable read-only memory devices. However, upon reissue, Xicor removed that limitation. The question before the court is whether that limitation was originally inserted to distinguish the claim from prior art. Judge Patel found that it was.

A reasonable, objective observer would conclude that the TEOS limitation was included in order to distinguish the claimed processes and process limitations from the prior art. By including the TEOS limitation, Xicor surrendered alternative chemicals to TEOS, and these alternatives were recaptured by claims 12 and 13 of the '370 reissue patent.

She declared the claims invalid and granted summary judgment for SST.

The case is Silicon Storage Technology, Inc. v. Xicor LLC No. C-10-1515 and the opinion is below the jump.


Silicon Storage Tech v. Xicor Patent MSJ