In the world of patent prosecution, professionals often find themselves grappling with the challenge of securing broad yet precise protection for their clients’ innovations. One particular hurdle patent practitioners face is the U.S. Patent and Trademark Office's (USPTO) penchant for a broad interpretation of terms like "substrate," "coating," and "layer." Sometimes the USPTO takes these terms to such extremes that circular definitions are reached where each encompasses the others. This blog post explores how patent examiners, armed with the principle of the broadest reasonable interpretation, wield these terms to encompass a spectrum of possibilities, often extending beyond what inventors might initially anticipate.
Consider, for example, the term substrate. USPTO examiners, utilizing the broadest reasonable interpretation standard, frequently interpret the term to be more than a base layer, even including multiple layers on a base layer as all being a substrate. This expansive approach can also extend to the term "layer” itself. Definitions from dictionaries can be of little help, since examiners cite definitions of substrate that include "layer," and definitions of layer including layers.
To shed light on the practical implications of this broad interpretation, let's delve into two typical, and recent, cases from the Patent Trial and Appeal Board (PTAB).
Case 1: Substrate Stretching Across Layers
In this case, (Appeal 2022-003498, Application 16/666,876), the claim on appeal required depositing the adhesion layer with certain components onto a substrate. The cited prior art by the examiner included three layers between its substrate and its manganese oxide layer and so the applicant argued the rejection was flawed since claim 20 requires the manganese oxide directly on the substrate (the bottom most layer). Claim 20 is reproduced below:
But the PTAB affirmed the rejection, confirming the examiner was correct to utilize a broad interpretation of the term substrate. From the PTAB decision:
The premise of Appellant’s arguments is, in part, that the Examiner has taken an unreasonably broad interpretation of the recited “substrate.” We disagree. The claim is open-ended and only requires that the substrate comprises “fused silica, aluminoborosilicate glass, or glass-ceramic”. Thus, all of the layers [in the prior art] may be fairly relied upon as collectively being a substrate, and depositing the manganese oxide layer onto [one of the upper layers of the prior art] is fairly encompassed by the claimed depositing of manganese oxide “directly onto a surface of a substrate” with the substrate “comprising fused silica, … or glass-ceramic” as recited in claim 20.
Thus, the claimed substrate was interpreted to encompass the combination of multiple layers in the prior art. Here, the term "substrate" was broadly construed, emphasizing the need for patent professionals, particularly those in semiconductor manufacturing and related fields to exercise caution when using terms that could inadvertently broaden the scope of their claims
Case 2: The Elusive Coating Layer
In this case, (Appeal 2022-004541, Application 16/917,249), the patent claimed a coating layer with a mixture of elements, resembling two separate layers in the prior art. The layers were applied to a drinking straw, with claim 34 on appeal reproduced below:
The examiner alleged that the prior art's use of different layers for the different components was sufficient to show the claimed coating since the two layers together were considered a mixture that formed the coating. The PTAB first considered the proper interpretation of the term mixture. As part of the analysis, the PTAB reviewed the specification to look for broad language that might indicate the claims are intended to cover multiple separate layers within the claimed part of the mixture. Not finding any such language in the specification, the PTAB reversed, noting the normal definition of a mixture:.
The claims on appeal call for a mixture of HPMC or a modified cellulose, an acidulating material or citric acid, and one or more active agents. Appeal Br 11–12, claims 34 and 39 (Claims App.). The Specification does not define the term “mixture,” although it discloses combining the modified cellulose with water, with or without heating, before the active agent is added. (See, e.g., Spec. 7:19–24, 10:18–23, 11:8–13.) … We use the Specification to more fully understand what Appellant claims and we find no indication that the claim term “mixture” includes a layering of the active agent onto the other components, as taught in [the prior art]. Accordingly, we limit the interpretation of the term “mixture” to exclude layering of ingredients…
Thus, the claimed coating was determined not to read on the prior art.
Practice Tips for Patent Practitioners:
Given the challenges posed by the USPTO's broad interpretation tendencies, patent professionals working in technologies like semiconductor manufacturing should consider the following tips:
Precision in Terminology: Be meticulous in the choice and definition of terms such as "layer" “coating” and "substrate" to avoid unintended broadening of claim scope.
Strategic Use of Definitions: Consider clearly defining key terms within the specification to provide a solid foundation for claim construction, leaving less room for expansive interpretations, particularly when describing a multi-layered structure. Negatively language may be particularly useful here.
Fallback Positions: Anticipate potential broad interpretations and include fallback positions in the specification that enable narrowing the claims when necessary, distinguishing between combined or separate layers. But be careful that the fallback language itself cannot be interpreted broadly, in which case there may be no fallback at all.