BPAI uses dependent claim to find independent claim to be indefinite

Takeaway: In a case involving chemical compounds in a transistor structure, the BPAI used a dependent claim to enter a new indefiniteness rejection for the independent claim. The Board found that both the Applicant's claim construction and the Examiner's were plausible, leading to an indefiniteness rejection under Ex parte Miyazaki. The Board noted that the Applicant's claim construction argument for the independent claim appeared to be at odds with the limitations in a dependent claim. (Ex parte Hoffman.)

Details:

Ex parte Hoffman
Appeal 2009008056; Appl. No. 10/799,961; Tech. Center 2800
Decided  July 27, 2011

The technology in this application involved the structure of a transistor. A representative independent claim on appeal read:

l. A semiconductor device, comprising:
   a drain electrode;
   a source electrode;
   a channel contacting the drain electrode and the source electrode,
   wherein the channel includes one or more compounds of the formula AxBxOx, 
   wherein the one or more compounds of the formula AxBxOx includes one or more of gallium-germanium oxide, gallium-tin oxide, gallium-lead oxide, indium-germanium oxide, indium-lead oxide, each O is atomic oxygen,
   where each x is a non-zero number, but the value of “x” for each constituent element may be different,
   wherein the channel includes one of an amorphous form and a mixed-phase crystalline form; and a gate dielectric positioned between a gate electrode and the channel.

On appeal, all claims were rejected as obvious. One of the underlying issue was the interpretation of the limitation "compounds of the formula AxBxOx." Citing Ex parte Davis (CCPA 1948), the Examiner took the position that the transition "comprising" meant that the "limitations are open-ended and the compounds (AxBxOx) referred to therein can contain other elements." This interpretation read on compounds of the form AxCxBxOx, so that the gallium-indium-tin oxide (indium = C) disclosed in the primary reference read on the claimed compound.

In the Appeal Brief, the Applicant acknowledged that "comprising" leaves the claim open to unrecited elements. But the Applicant also argued that: 

The term "comprising" does not mean that the Examiner can alter or disregard the elements specifically recited. ... [and] does not license the Examiner to change or add to the chemical compounds specifically and expressly recited.

In the Answer, the Examiner buttressed his claim interpretation by referring to various claims depending from claim 1. Dependent claim 6 read “wherein the one or more compounds of the formula AxBxOx includes Cx to form a compound of the formula AxBxCxOx.” In order for claim 1 to be broader than claim 6, the “formula AxBxOx” limitation must encompass the claim 6 compound AxBxCxOx, and therefore the formula limitation must be open-ended.

The Applicant filed a Reply Brief and continued to argue against the Examiner's claim interpretation. The Applicant discussed the precedent related on by the Examiner: 

[Ex parte Davis] does hold that a the term "comprising" leaves a claim open for the inclusion of additional recited elements. It is, however, a complete mischaracterization of Davis to argue that Davis holds that each limitation is individually open-ended, such that the recitation of a particular chemical compound can be essentially ignored and transfigured into a recitation of any compound comprising the recited and additional constituents. Such an unreasonable interpretation would make it unreasonably difficult for an applicant to specify precisely the desired chemical compounds to be recited in a claim. The Examiner's interpretation of Davis is unreasonable, unworkable and utterly without supporting authority!

The Board reversed the obviousness rejections on grounds other than claim construction. Specifically, the Board found no reason to replace the semiconducting indium-tin oxide in the channel layer of the primary reference with the highly conductive transparent conducting materials of the second reference.

However, the Board did address the claim construction issue in another way: by finding that independent claim 1 was amenable to two plausible interpretations and thus indefinite under Ex parte Miyazaki.

[T]he claim 1 term of “compounds of the formula AxBxOx” is amenable to two or more plausible claim constructions (i.e., one being open ended as argued by Appellants and one being closed-ended as presented by the Examiner), thereby justifying requiring Appellants to more precisely define the metes and bounds of the claimed invention by holding the claim unpatentable under 35 U.S.C. § 112, second paragraph, as indefinite. See Miyazaki, 89 USPQ2d at 1211.

My two cents: I don't do chemical cases, so I won't say which claim interpretation is the best one. But – still speaking as a person NOT skilled in the chemical arts – the arguments offered on both sides seem reasonable. Based on that, I'm inclined to agree with the Board's indefiniteness rejection under Miyazaki. On the other hand, I'm not sure "reasonable" is the same as "plausible." And I just don't know enough about chemical practice to say if both are plausible or not.

I wonder if another theme underlying the indefiniteness rejection was the "confusion" caused by the dependent claim. I say that because the Applicant seemed to have the better argument about the use of comprising. Remember, " 'comprising' is not a weasel word with which to abrogate claim limitations." Spectrum Int'l, Inc. v. Sterilite Corp., 164 F.3d 1372, 1380 (Fed.Cir.1998). Would the indefiniteness rejection have been avoided if the dependent claim wasn't there to confuse things?

I noticed that several other dependent claims used the same format. For example, claim 10 dependent from claim 6 and read "the one or more compounds of the form AxBxCxOx. includes Dx to form a compound of the formula AxBxCxDxOx." So it appears that this claim format was intentional.