Federal Circuit Invalidates Synopsys’ Chip Design Patents as Unpatentable Abstract Ideas

| Lincoln S. Essig

The Federal Circuit’s recent decision in Synopsys, Inc. v. Mentor Graphics Corp., Case No. 2015-1599 (Fed. Cir. Oct. 17, 2016), upholding the lower court’s grant of summary judgment of invalidity under § 101, may provide another tool to patent challengers wishing to invalidate claims arguably reciting mental processes. In deciding the case, the Federal Circuit relied on the two-step analytical framework of Mayo/Alice, and found that the claimed methods were directed to unpatentable abstract ideas without reciting “significantly more.”

Step 1: Are the Asserted Claims Directed to an Abstract Idea?

Under step one of the Mayo/Alice test for subject matter eligibility, a court is to determine whether the claims at issue are directed to a patent-ineligible concept, such as an abstract idea. Here, the Federal Circuit reviewed Claim 1 of U.S. Patent No. 5,530,841 (the ’841 patent), which the parties had agreed was representative of all asserted claims, and affirmed the district court’s ruling that the claims were directed to a mental process. Claim 1 reads as follows:

 A method for converting a hardware independent user description of a logic circuit, that includes flow control statements including an IF statement and a GOTO statement, and directive statements that define levels of logic signals, into logic circuit hardware components comprising:

converting the flow control statements and directive statements in the user description

for a logic signal Q into an assignment condition AL(Q) for an asynchronous load function AL( ) and an assignment condition AD(Q) for an asynchronous data function AD( ); and

generating a level sensitive latch when both said assignment condition AL(Q) and said assignment condition AD(Q) are nonconstant;

wherein said assignment condition AD(Q) is a signal on a data input line of said flow

through latch;

said assignment condition AL(Q) is a signal on a latch gate line of said flow through latch; and an output signal of said flow through latch is said logic signal Q.

In affirming the district court, the Federal Circuit found the claims “so broad as to read on an individual performing the claimed steps mentally or with pencil and paper,” Id. at 21, and further noted that, on their face, the claims did not require a computer. Before reaching this conclusion, the court provided several pages of background on the general concepts of binary logic, flow control statements, directive statements, asynchronous load functions, and asynchronous data functions. Id. at 5-12. The court’s reasoning that the claimed steps can be performed mentally or with pencil paper was based on  (1) hardware description language (HDL) code for level sensitive latches existed in the prior art (as conceded in the asserted patents), (2) circuit diagrams for level sensitive latches existed in the prior art (also conceded in the asserted patents), and (3) the process for interpreting the HDL code to identify the circuit diagram as the hardware that performs the function recited in the HDL code can be performed mentally or with pencil and paper. Id. at 11.  

In addition, although the court mentioned that it need not decide whether a computer-implemented version of the invention would be directed to an abstract idea, it cited  Gottschalk v. Benson for the premise that claimed methods designed for use on a computer may nonetheless be patent-ineligible if they can also be performed without a computer. See Gottschalk v. Benson, 409 U.S. 63 (1972).

Synopsys’ arguments that the asserted claims did not preempt all conversions from functional descriptions to hardware component descriptions of logic circuits did not persuade the court.

Alice Step 2: Do the Asserted Claims Include an Inventive Concept

Under step two of the Alice test for subject matter eligibility, a court is to determine whether the additional elements transform the nature of the claim into a patent-eligible application, which has also been described as a search for an inventive concept. Slip op. at 15.

In this step of the analysis, the court dismissed Synopsys’ contention that the claims contained an inventive concept because they were not shown to have been anticipated by or obvious over prior art as a misstatement of the law. Slip op. at 24. Instead, the court stated that “a claim for a new abstract idea is still an abstract idea.” Id.

The court went on to distinguish the claims from the claims upheld as valid in both DDR Holdings and BASCOM stating that the asserted claims did not contain any technical solution, technical advance or improvement, as did the claims in the aforementioned cases. Therefore, the court concluded that the claims contained nothing that “amounts to significantly more than a patent upon the [abstract idea] itself,” as found in Alice.


Even if a person of ordinary skill in the art would, in practice, perform claims on a computer, such claims which do not recite a computer or any other physical component, and which broadly recite concepts viewed as mental processes, are likely to be held invalid by the Federal Circuit. However, as the court states in its conclusion in this case, different claims directed to “a computerized design tool [..] to more efficiently identify and generate [the same output]” could possibly pass muster under § 101.