IP Law Daily PTAB correctly rejected claims of Knowles MEMS package patent
Thursday, March 1, 2018

PTAB correctly rejected claims of Knowles MEMS package patent

By Robert Margolis, J.D.

The Patent Trial and Appeal Board correctly rejected several claims in Knowles Electronics, LLC’s, patent for a Microelectromechanical System Package as invalid and other claims as unpatentable due to an insufficient written description, the U.S. Court of Appeals for the Federal Circuit has held in a precedential opinion. The PTAB in this case was not required to follow the construction of a key claim term adopted in prior litigation involving the same patent (Knowles Electronics LLC v. Cirrus Logic, Inc., March 1, 2018, Wallach, E.).

Knowles appealed the PTAB’s reexamination decision after an examiner rejected for anticipation claims 1-4 of Knowles’s U.S. Patent Nos. 6,781,231 (the "’231 Patent"), and the ’231 Patent’s proposed claims 23-27 for lack of sufficient written description. The ’231 Patent, "Microelectromechanical System Package with Environmental and Interference Shield," discloses microelectromechanical system (MEMS) packages made up of a substrate, microphone, and cover for the microphone. The MEMS packages shield the microphone from interference signals or environmental conditions. The packages purport to improve on prior art manufacturing processes for the covers.

Claim construction of MEMS "package." Knowles appealed the PTAB’s decision that claims 1-4 are invalid, contending that the PTAB improperly rejected the "potentially most commonly accepted definition of ‘package.’" The court disagreed, finding no error in the PTAB’s claim construction.

The PTAB found that under the broadest reasonable interpretation, a "package" "may refer to chip assemblies that possess any type of second-level connection mechanism." Knowles contended that this was in error, that "package" means an assembly requiring "a second-level connection with a mounting mechanism." Knowles disagreed with the PTAB’s construction not requiring a "mounting mechanism." The court pointed out that claims 1-4 did not specify the required connection for forming the MEMS package, nor did the patent’s specification limit the type of connection to one that is mountable or has any particular form of mount. Nor were any disclosures in the prosecution history helpful in construing "package," the court found.

The court considered both intrinsic and extrinsic evidence, because the intrinsic evidence was not definitive. While Knowles asked the court to consider only certain dictionary definitions and treatise references describing common mounting categories, the PTAB pointed out that many of Knowles’s references used qualifying language, thus implying that circuit board second-level connections may not be properly limited by the two types of mounts that Knowles proffered. In fact, some of Knowles’s evidence supported the PTAB’s conclusion that a package need not have the types of second-level connection mounts that Knowles proffered.

The PTAB, on the other hand, had cited references that allow for connectivity mechanisms beyond the surface and through-hole mounting mechanisms that Knowles had argued. Contrary to Knowles’s assertion that the PTAB defaulted to the "broadest definition" that the parties had cited, the court found that the PTAB reviewed all extrinsic evidence, including what Knowles had proffered, to reach its conclusion.

Prior court construction. The court also rejected Knowles’s argument that because in prior litigation concerning the same patent the court had construed "package" as requiring only that it be "a self-contained unit" and the unit "be mountable," the PTAB was bound to follow that construction in this case. The court examined the claim construction in the prior case, MEMS Tech. Berhad v. Int’l Trade Comm’n, 447 F. App’x 142 (Fed Cir. 2011), where it had approved the International Trade Commission’s construction of "package" in the ’231 Patent’s preamble to mean "a self-contained unit that has two levels of connection, to the device and to a circuit or other system." According to the court, this prior decision did not require a package be mounted via surface or through-hole mounts, as Knowles argued here, so the prior holding was not inconsistent.

Insufficient written description. The PTAB had determined that claims 23-27 of the ’231 Patent were unpatentable because of their insufficient written description. Those claims recite a MEMS package involving solder pads that are "configured to mechanically attach and electronically connect the package to a surface of an external printed circuit board using a solder reflow process." According to the PTAB, this description was deficient because while it disclosed the "genus," solder pads capable of being connected to a board, it did not disclose the "species of such pads—pads that are connectable to a board specifically by using a reflow process." Knowles argued that a person having ordinary skill in the art would understand that solder pads could be attached through reflow. The court disagreed with Knowles.

The court noted that Knowles did not contend that the specification identified "solder reflow process" as a means to connect solder pads to the circuit board, nor did Knowles contest that in fact other processes for connecting were known in the art when the invention was made, and indeed were in the PTAB’s evidentiary record. Thus, the court found that the evidentiary record supported the PTAB’s conclusion that the description was deficient for failing to adequately describe the reflow process limitation.

Dissent. Circuit Judge Evan J. Wallach took issue with the majority’s "erroneous position" that the PTAB was not required to follow the earlier MEMS Tech. decision on the same issue for the same patent. The PTAB had stated that it was not bound in reexamination proceedings by a court’s prior claim construction. The dissent noted that the majority did not discuss whether issue preclusion applied, and thus by silence reinforced the PTAB’s incorrect position.

The case is No. 2016-2010

Attorneys: Richard L. Rainey (Covington & Burling LLP) for Knowles Electronics LLC. Nathan R. Speed (Wolf, Greenfield & Sacks, PC) for Cirrus Logic, Inc.

Companies: Knowles Electronics, LLC; Cirrus Logic, Inc.; Cirrus Logic International (UK) Ltd.

MainStory: TopStory Patent FedCirNews

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