Claim Construction Leads to Unpatentability for Lack of Written Description Support

Holding

In Tokyo Ohka Koygo., Ltd. v. Fujifilm Electronic Materials U.S.A., Inc., PGR2022-00010, Paper 28 (P.T.A.B. May 31, 2023), the Patent Trial and Appeal Board (“the Board”) held all challenged claims unpatentable for obviousness.

Background

Petitioner Tokyo Ohka Koygo (“TOK”) challenged claims 1-5 of Fujifilm’s U.S. Patent No. 10,927,329 (“the ’329 patent”) as unpatentable for obviousness under 35 U.S.C. §103 and lack of written description under §112(a). Independent claim 1 read:

1. 1. A cleaning composition, comprising:
      1. hydroxylamine;
      2. an alkanolamine in an amount of at most about 3% by weight of the composition; 
      3. an alkylene glycol; and
      4. water

wherein the pH of the composition is from about 7 to about 11.

The parties disputed the proper construction of the claim term “cleaning composition.” The parties agreed that the term refers to “a composition for removing residues from substrates.” Id. at *6. However, Patent Owner Fujifilm argued that “cleaning composition” should be construed to additionally include “at least a redox agent, a chelating agent, a metal corrosion inhibitor, an organic solvent, and water.” Id. at *7.

Board Decision

The Board noted that the claim language does not specify a purpose for the cleaning composition, but the specification “consistently states that the disclosed cleaning composition is for removing residues formed on semiconductor substrates.” Id. at *7. According to the Board, Patent Owner Fujifilm’s proposed construction would improperly rewrite the claim. Because the intrinsic evidence was “unambiguous,” the proper construction is limited to the four components expressly recited in the claim. Id. at *11. The Board explained:

Although the ’329 patent describes a cleaning composition that comprises a redox agent, a chelating agent, a metal corrosion inhibitor, an organic solvent, and water, we see no reason to construe the term “cleaning composition” itself to require these components. Claim 1 expressly recites the components that comprise the claimed “cleaning composition,” without expressly including or precluding a chelating agent or a metal corrosion inhibitor. … The ’329 patent specification does teach a cleaning composition that includes a redox agent, a chelating agent, a metal corrosion inhibitor, an organic solvent, and water, but claim 1 is directed to a cleaning composition that expressly requires only a subset of those components.

Id. at *8-9.

Under this construction, the Board agreed with Petitioner TOK that the challenged claims lacked written description support. “The ’329 patent does not reasonably convey to a POSA that the inventor was in possession of cleaning compositions that do not include a chelating agent or a metal corrosion inhibitor.” Id. at *13 (emphasis added).

[T]he ’329 patent specification explicitly teaches that a redox agent, a chelating agent, a metal corrosion inhibitor, an organic solvent, and water are mandatory components of the cleaning composition described therein. . . . Claim 1, however, does not require that the cleaning composition include a chelating agent or a metal corrosion inhibitor. . . . Therefore, establishing proper written description support for claim 1 requires more than showing that the inventor was in possession of a cleaning composition that includes a redox agent, a chelating agent, a metal corrosion inhibitor, an organic solvent, and water; the ’329 patent must also show that the inventor was in possession of a cleaning composition that includes only a redox agent (hydroxylamine), an organic solvent (an alkylene glycol), water, and an alkanolamine.   

Id.

The Board did not reach the obviousness grounds.

Take-aways

For the prosecutor, this case is a reminder to avoid wherever possible disclosing but not claiming subject matter. Disclosed but unclaimed subject matter is dedicated to the public, and, as seen in this case, may potentially lead to written description support issues.

For the PTAB practitioner, this case illustrates why a party may want to consider including alternative positions in its briefing. Here, the Board noted that Patent Owner Fujifilm “does not address whether the challenged claims are sufficiently supported by the ’329 patent using any other construction of ‘cleaning composition.’” As a result, the Board concluded that Fujifilm’s written description position was unrebutted.