PTAB

IPR2022-01196

PDF Solutions Inc v. Ocean Semiconductor LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for Filtering Metrology Data Based on Collection Purpose Data
  • Brief Description: The ’691 patent discloses methods and systems for improving process control in semiconductor manufacturing. The invention involves collecting metrology data from processing tools, generating associated context data that includes a specific "collection purpose" (e.g., for process control vs. fault detection), filtering the metrology data based on this stated purpose, and then conducting a process control activity using only the filtered data.

3. Grounds for Unpatentability

Ground 1: Obviousness over Bushman and Yelverton - Claims 1-19 are obvious over Bushman in view of Yelverton.

  • Prior Art Relied Upon:

    • Bushman: S. Bushman et al., Integration of the APC Framework with AMD’s Fab25 Factory System, Proc. SPIE 3882 (1999).
    • Yelverton: M. Yelverton et al., Factory-Wide Run-to-Run Process Control, Solid State Technology, Vol. 42, No. 12 (1999).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that the combination of Bushman and Yelverton taught all limitations of the challenged claims. Bushman described an Advanced Process Control (APC) framework for AMD's fabrication facility that collected metrology data from multiple tools, used "context" information associated with the data, and included the capability to "filter the metrology data, if appropriate." Bushman’s system used this data to perform process control, such as updating recipe parameters. While Bushman taught using "context," Yelverton explicitly taught the need for "proper fault detection and classification logic" to deal with faulty metrology measurements arising from sources like "bad wafers" or operator error. Petitioner contended that Yelverton’s "classification" of data as correct or faulty is the same as the ’691 patent's "collection purpose." By implementing Yelverton's classification logic, a system like Bushman's would filter data based on its purpose (e.g., excluding data classified as faulty/for fault diagnosis from use in run-to-run process control), thereby rendering the claimed invention obvious.

    • Motivation to Combine: Petitioner asserted several strong motivations for a person of ordinary skill in the art (POSITA) to combine the references. A POSITA would combine Bushman and Yelverton because both documents addressed the same field of advanced process control for semiconductor manufacturing and were published in the same year. Critically, both references were directly related to Advanced Micro Devices (AMD), the original assignee of the ’691 patent; Bushman described the APC framework for AMD’s Fab25 factory, and Yelverton’s lead author was an AMD employee. A POSITA implementing Bushman’s general APC framework would have been motivated to incorporate Yelverton’s specific teachings on handling faulty metrology data to improve the system's reliability and yield, a well-known goal in the industry. Yelverton provided a known solution—classifying and filtering faulty data—to the known problem of process control being negatively affected by unreliable measurements.

    • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references. Bushman’s framework was designed to be modular and already included a "Fault Manager" and the ability to filter data. Integrating Yelverton’s explicit logic for classifying data based on its reliability (e.g., faulty vs. non-faulty) into Bushman’s system would have been a straightforward implementation of complementary concepts to achieve a more robust and predictable process control system.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial would be unjustified under both 35 U.S.C. §314(a) (Fintiv factors) and 35 U.S.C. §325(d).
  • Fintiv Factors: Petitioner contended that denial was not warranted because, among other reasons, (1) co-pending district court cases have no set trial dates, and similar cases have been stayed pending IPR outcomes; (2) Petitioner is not a party to the co-pending litigation; and (3) this petition raises entirely different prior art and arguments than a previously denied IPR petition filed by another party (the AMAT Pet.), weighing heavily in favor of institution.
  • §325(d) Factors: Petitioner argued that denial under §325(d) was inappropriate because the primary references, Bushman and Yelverton, were never presented to or considered by the USPTO examiner during the original prosecution of the ’691 patent. Therefore, the petition raised new questions of patentability that the Office had not previously considered.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-19 of the ’691 patent as unpatentable.