Entegris Inc v. Inpria Corp

1. Case Identification

• Case #: IPR2025-00267
• Patent #: 11,673,903
• Filed: December 12, 2024
• Petitioner(s): Entegris, Inc.
• Patent Owner(s): Inpria Corp.
• Challenged Claims: 1-4, 6-10

2. Patent Overview

• Title: High Purity Monoalkyltin Compounds and Uses Thereof
• Brief Description: The ’903 patent discloses high-purity liquid compositions of monoalkyltin triamides and methods of using them. The purported novelty is not the compounds themselves, which were known, but achieving a specific purity level of no more than 0.5 mole % dialkyltin compound impurities.

3. Grounds for Unpatentability

Ground 1: Anticipation by Hänssgen - Claims 1-4 and 6-10 are anticipated by Hänssgen under 35 U.S.C. §102.

• Prior Art Relied Upon: Hänssgen (“Synthesis of The First Mono-t-Butyltin Element Compounds,” a 1985 journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Hänssgen discloses every limitation of the challenged claims. Hänssgen describes the synthesis of a monoalkyltin triamide, t-BuSn(NEt2)3, which meets the structural limitations of independent claims 1 and 10. For the key purity limitation, Hänssgen stated the reaction "proceeds quantitatively" with "no indications of secondary reactions" and that an "analytically pure" product can be obtained via distillation. Petitioner asserted this language inherently discloses a composition with no more than 0.5 mole % dialkyltin impurity. To support this, Petitioner submitted results from its own recreation of the Hänssgen synthesis, which reportedly yielded a product with only 0.17 mole % dialkyltin impurity, well within the claimed limit.
  • Key Aspects: Petitioner contended that its successful experimental replication of Hänssgen’s method directly contradicts declarations filed by the Patent Owner during prosecution, which had claimed the prior art could not achieve the required purity.

Ground 2: Obviousness over Meyers and Deelman - Claims 1-4 and 6 are obvious over Meyers in view of Deelman under 35 U.S.C. §103.

• Prior Art Relied Upon: Meyers (Application # 2016/0116839) and Deelman (Application # 2011/0166268).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued Meyers teaches the synthesis of a monoalkyltin triamide compound, i-PrSn(NMe2)3, that meets all structural limitations of the claims and further teaches that high-purity precursors are desirable for its intended use in organometallic coatings. While Meyers does not specify a purity level, Deelman explicitly teaches the importance and achievement of high-purity monoalkyltin compounds (up to 99.999 wt%), including those with only "minor quantities of di- and/or trialkyltin compounds." Deelman also discloses the same general synthesis pathway as Meyers: converting monoalkyltin trihalides into other derivatives.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA), starting with the monoalkyltin triamide taught in Meyers and recognizing the stated desire for high purity, would have been motivated to look to Deelman. Deelman directly addresses achieving high purity for the same class of compounds using the same synthesis strategy. A POSITA would combine Deelman’s teachings on purity with Meyers’ specific compound to achieve a predictably high-purity final product.
  • Expectation of Success: The combination involved applying known purification principles and synthesis pathways to a known class of compounds. The reaction to convert a high-purity trihalide (taught by Deelman) to a high-purity triamide (taught by Meyers) is a well-defined and predictable exchange reaction. Petitioner’s own experiments, allegedly combining the teachings, reportedly produced a compound with only 0.19 mole % dialkyltin impurity, demonstrating the expected success.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Meyers and Deelman in view of Hänssgen for claims 7-10, and combinations of Deelman and Jones (a 1965 journal article) for claims 1-4 and 6, with further addition of Hänssgen for claims 7-10. These grounds relied on similar motivations to achieve high purity and combine known synthesis techniques for organotin compounds.

4. Key Technical Contentions (Beyond Claim Construction)

• Patent Owner’s Prosecution Declarations Were Flawed and Misleading: A central argument woven throughout the petition is that the patent was allowed based on material error by the USPTO, induced by inaccurate declarations from the inventor. Petitioner contended that the inventor’s attempts to replicate prior art failed not because the art was deficient, but because the experiments were designed to fail. For example, the inventor allegedly attempted to synthesize a moisture-sensitive monoalkyltin triamide using an aqueous solution, a method a POSITA would know is improper and would cause the compound to hydrolyze, thereby preventing the formation of a high-purity product. Petitioner contrasted these "flawed" experiments with its own "proper" replications that successfully achieved the claimed purity.

5. Arguments Regarding Discretionary Denial

• Denial under §325(d) is Unwarranted: Petitioner argued that although the Examiner considered some of the asserted prior art (Meyers and Deelman), reconsideration is necessary for two reasons. First, the petition presents new arguments and combinations not previously considered (e.g., Deelman in view of Jones). Second, the Office committed a material error by withdrawing rejections and allowing the claims in reliance on the Patent Owner's allegedly incorrect and misleading declarations. Petitioner’s new experimental evidence is presented to directly prove this error.
• Denial under Fintiv is Inapplicable: Petitioner argued that discretionary denial under Fintiv is not appropriate because, while the ’903 patent is asserted in a parallel district court case, Petitioner is not a party to that litigation.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-4 and 6-10 of the ’903 patent as unpatentable.