Federal Circuit Finds No Written Description In Genus/Species Disclosure Case
On March 1, 2018, the United States Court of Appeals for the Federal Circuit (CAFC) ruled that a patent that disclosed a technological genus (solder pads) did not provide written-description support for claims to one species within that genus (solder pads configured for connection via a solder reflow process), even though the record showed that the species was known to those of skill in the art at the time of the invention. Knowles Electronics LLC v. Cirrus Logic, Inc., appeal no. 2016-2010.
Knowles Electronics LLC is the owner of a patent challenged by several parties, including Cirrus Logic, Inc., in an inter parties reexamination. On an appeal of the examiner’s decisions in the reexamination, the Patent Trial and Appeal Board (PTAB) found four claims of the patent invalid for anticipation based on a claim-construction ruling. The PTAB also found that four proposed additional claims would be unpatentable for lack of written-description support in the specification. See 35 U.S.C. § 112 (“The specification shall contain a written description of the invention, and of the manner and process of making and using it, in … full, clear, concise, and exact terms ….”). The CAFC affirmed the PTAB’s claim construction and thus affirmed the anticipation finding.
The written-description issue concerned a limitation common to all four proposed new claims: “a MEMS package wherein the solder pads are ‘configured to mechanically attach and electrically connect the package to a surface of an external printed circuit board using a solder reflow process.’” The CAFC opinion explains that a solder-reflow process is one way of attaching a MEMS package to a circuit board, but not the only way. The opinion also explains that the patent specification describes solder pads, but does not describe “any particular process” for connecting the pads to a circuit board.
Apparently, solder reflow was one of several attachment processes well-known to those of skill in the art at the time of the invention. Knowles argued that the PTAB erred by ignoring “prior art references that disclose solder reflow as a well-known process of connecting mount devices.” In response, the CAFC pointed out that the PTAB had considered this evidence and correctly “found that other processes of connection existed in the prior art.” Nothing in the specification described a solder-reflow process (or any other connection process) either explicitly or inherently. Indeed, “Knowles did not contend that the specification necessarily disclosed a solder reflow process.” Absent such a disclosure, the CAFC ruled, the claims that included the solder-reflow limitation are unpatentable for lack of written description.
Thus, a possible result of the CAFC’s rulings is that the broader claims, which did not include any limitation at all discussing an attachment process, could be sufficiently described in the specification, while the narrower claims, which include the solder-reflow attachment limitation, are not—even though it was apparently uncontested that attachment in general was described in the specification, and that solder reflow was one of several different attachment processes well-known to those of skill in the art at the time of the invention.
The case thus illustrates how tightly a patent disclosure is read when performing a written-description analysis on a narrow claim. The CAFC ruling required Knowles to show not only that its claimed species was one of those known to those of skill in the art at the time of the invention, but that the claimed species was the only one known to those of skill in the art. It did not matter that those of skill in the art knew of solder reflow, because the specification did not show that the inventor knew of solder reflow in particular.