PTAB

IPR2019-00371

ASM IP Holding B.V. v. Kokusai Electric Corp.

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1. Case Identification

2. Patent Overview

  • Title: Method of Manufacturing a Semiconductor Device
  • Brief Description: The ’316 patent describes methods for manufacturing semiconductor devices by forming a thin film on a substrate. The method involves cyclically repeating a two-step process: (1) depositing a first layer that is either "less than one atomic layer" or "several atomic layers" thick, and (2) modifying that first layer with a second element "without saturating" the reaction. The patent purports to cover non-ideal atomic layer deposition (ALD) processes that result in either sub-monolayer or multi-layer deposition per cycle.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-2, 5, and 14 by Kim

  • Prior Art Relied Upon: Kim (WO 2004/094695).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kim anticipates the claims reciting deposition of "less than one atomic layer." Kim disclosed a "starved exposure" ALD process for forming an aluminum oxide film, where precursor doses are "insufficient to result in a maximum saturated ALD deposition rate." This sub-saturating process inherently formed a discontinuous first layer of trimethylaluminum (TMA) less than one atomic layer thick, directly meeting limitation 1[iii][a]. Kim then disclosed modifying this TMA layer with a sub-saturated dose of water (H2O) vapor, which did not fully saturate the reaction, meeting limitation 1[iii][b]. Dependent claim 2 was met because Kim’s process occurred in a heated, decompressed, non-plasma atmosphere.
    • Key Aspects: The core of this argument was that Kim’s "starved exposure" is synonymous with the ’316 patent’s "less than one atomic layer" deposition, a process Petitioner contended was well-known to address real-world, non-ideal ALD behavior.

Ground 2: Obviousness of Claims 6-13 and 15-16 over Kim in view of Forbes

  • Prior Art Relied Upon: Kim (WO 2004/094695) and Forbes (Application # 2008/0057659).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claims directed to three- and four-element films (e.g., HfAlON). Petitioner asserted that Kim provided the foundational "starved exposure" method and expressly taught its applicability to forming films with three or more elements. Forbes, entitled “Hafnium Aluminum Oxynitride High-K Dielectric and Metal Gates,” taught a specific, preferred sequence of precursor pulses (aluminum, oxygen, hafnium, nitrogen) for creating HfAlON films. The combination of Kim's method with Forbes's recipe allegedly rendered the claimed multi-element film processes obvious. For example, claim 6, which adds a third element, was obvious by applying Kim's starved-exposure technique to the multi-element process detailed in Forbes.
    • Motivation to Combine: A person of ordinary skill in the art (POSA) seeking to create a high-quality, multi-element film like HfAlON using an efficient method would have been motivated to combine Kim’s advantageous starved-exposure process with Forbes’s well-defined, predictable sequence for HfAlON deposition.
    • Expectation of Success: A POSA would have had a high expectation of success because Kim provided the general method and its benefits, while Forbes provided a specific, successful recipe for the target film, leaving no undue experimentation required for the combination.

Ground 3: Anticipation and Obviousness of Claims 1, 3-4, 6, 10, and 14-16 over Haverkort

  • Prior Art Relied Upon: Haverkort (Patent 7,294,582).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Haverkort anticipated or rendered obvious the claims reciting deposition of "several atomic layers." Haverkort disclosed a method of forming a silicon nitride (SiN) film by first depositing a thin silicon layer of 8-20 Å, which corresponds to several atomic layers, meeting limitation 1[iii][a]. Haverkort then taught modifying this silicon layer via nitridation, reporting a final film stoichiometry of Si45N56. This ratio (1.25 N atoms per Si atom) is less than that of perfectly stoichiometric Si3N4 (1.33 N atoms per Si atom), which Petitioner argued was an express disclosure of a non-saturating reaction that met limitation 1[iii][b].
    • Motivation to Combine (for §103 grounds): For dependent claims, Haverkort taught minimizing nitridation depth to avoid affecting underlying layers, motivating a POSA to modify only the surface layer (as in claim 3). For multi-element film claims (6 and 10), Haverkort explicitly disclosed forming three-element (SiON) and four-element (SiOCN) films by adding subsequent oxidation and carbonization steps to its base SiN process, making these combinations obvious.
    • Expectation of Success: Haverkort provided detailed process parameters and working examples for its deposition methods, giving a POSA a clear path and reasonable expectation of success in producing both the base SiN films and the more complex multi-element variants.

4. Key Claim Construction Positions

  • "less than one atomic layer": Petitioner argued, based on the patent’s specification and prosecution history, that this term means a "discontinuous atomic layer" where potential reaction sites on the substrate remain unreacted. This construction was central to mapping Kim's "starved exposure" process directly onto the claim language.
  • "without saturating a modifying reaction": Petitioner asserted this phrase means that some, but not all, of the first layer remains unreacted with the second element. This construction was used to show that the non-stoichiometric and sub-saturated reaction products described in both Kim and Haverkort met this claim limitation.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-16 of the ’316 patent as unpatentable.