Western Digital Technologies Inc v. Ocean Semiconductor LLC

1. Case Identification

• Case #: IPR2021-00864
• Patent #: 6,660,651
• Filed: April 29, 2021
• Petitioner(s): Western Digital Technologies, Inc.
• Patent Owner(s): Ocean Semiconductor LLC
• Challenged Claims: 19, 22, 72, 74-75, 77, 79, and 81

2. Patent Overview

• Title: Adjustable Wafer Stage, and Method and System for Performing Process Operations Using Same
• Brief Description: The ’651 patent discloses a method and system for semiconductor fabrication using a process tool with an adjustable wafer stage. The stage can be raised, lowered, or tilted by a plurality of actuators to compensate for variations in wafer thickness during processing operations.

3. Grounds for Unpatentability

Ground 1: Anticipation by Tanaka - Claims 19, 22, 72, 74-75, 77, 79, and 81 are anticipated under 35 U.S.C. §102 by Tanaka.

• Prior Art Relied Upon: Tanaka (WO 01/22480).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Tanaka’s first embodiment discloses every element of the challenged method claims. Tanaka teaches an exposure apparatus for manufacturing a device, which includes a process chamber (chamber 46) containing a wafer stage (WST) with an adjustable top surface. The stage’s position and orientation are controlled in three degrees of freedom (Z, θx, θy) by a parallel link mechanism comprising multiple telescopic rods, each containing a pneumatic air cylinder (84). Petitioner contended this directly teaches the claimed steps of providing a process chamber with an adjustable wafer stage, actuating pneumatic cylinders to raise, lower, and tilt the stage surface, positioning a wafer on the stage, and performing a process operation (lithographic patterning). Dependent claims were also argued to be disclosed, such as positioning the wafer before adjustment (claim 22).

Ground 2: Obviousness over Tanaka - Claims 19, 22, 72, 74-75, 77, 79, and 81 are obvious over Tanaka.

• Prior Art Relied Upon: Tanaka (WO 01/22480).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner presented this ground as an alternative, asserting that if Tanaka’s second embodiment were found not to explicitly teach a "process chamber," the claims would be obvious over Tanaka’s combined teachings. The second embodiment discloses a more advanced wafer stage adjustable in six degrees of freedom, also driven by pneumatic air cylinders. All other limitations of the challenged claims are met by this embodiment for the same reasons as the first embodiment.
  • Motivation to Combine (for §103 grounds): Tanaka explicitly stated that its first and second embodiments "may be used in combination as appropriate." A person of ordinary skill in the art (POSITA) would have been motivated to incorporate the hermetically-sealed process chamber from the first embodiment with the advanced six-degree-of-freedom stage of the second embodiment to gain the known benefits of a controlled environment (e.g., for vacuum ultraviolet lithography) and enhanced positioning accuracy.
  • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success, as the components were highly similar and combining them served the predictable purpose of improving an existing semiconductor processing apparatus.

Ground 3: Obviousness over Wakui and Magome - Claims 19, 22, 72, 74-75, 77, 79, and 81 are obvious over Wakui in view of Magome.

• Prior Art Relied Upon: Wakui (Japanese Application # JP H11-274031) and Magome (European Application # EP 1,030,351 A1).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Wakui taught most claim elements but did not expressly place its apparatus in a process chamber. Wakui discloses an exposure apparatus with a movable plate (wafer stage) adjustable in six degrees of freedom by a plurality of links containing extendable actuators, specified as including "air pressure cylinders." This system performs a process operation (patterning) on a wafer placed on the stage. Magome addresses the need for environmental control in such systems, disclosing an exposure apparatus sealed within an environmental chamber and subchambers to house the reticle and wafer stages, particularly when using VUV light sources.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Wakui’s adjustable stage with a process chamber as taught by Magome to achieve well-known benefits in advanced lithography. These benefits, taught by Magome, include preventing exposure-light attenuation, improving temperature control, and enabling vacuum operation. The combination would have been a routine implementation of a known solution (environmental control) to a known problem in a similar apparatus.
  • Expectation of Success (for §103 grounds): Success would be expected because enclosing processing equipment in a controlled chamber was a well-known, conventional, and predictable practice in the semiconductor manufacturing art to improve process results.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) based on the Fintiv factors would be inappropriate. The parallel district court case was in its infancy, with no trial date set, no schedule in place, and minimal investment by the court in the merits. Petitioner also contended there was minimal overlap between the IPR and the district court case, as it intended to rely on different prior art (product-based art) in litigation and would stipulate not to pursue the same grounds raised in the IPR. Finally, Petitioner asserted the merits of the petition were exceptionally strong, favoring institution.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 19, 22, 72, 74-75, 77, 79, and 81 of the ’651 patent as unpatentable.