PTAB

IPR2015-01279

ASML Netherlands BV v. Energetiq Technology Inc

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Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Laser Sustained Plasma Light Source
  • Brief Description: The ’455 patent is directed to a "laser sustained plasma light source" for applications such as testing and inspection in semiconductor manufacturing. The technology involves using an ignition source to create a plasma from a gas within a chamber, a laser to provide energy to sustain the plasma, and reflective surfaces to direct the resulting high-brightness light.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claim 19 - Claim 19 is anticipated under 35 U.S.C. §102 by Gärtner.

  • Prior Art Relied Upon: Gärtner (French Patent Publication No. FR2554302A1).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Gärtner, which was not considered during prosecution, discloses every element of claim 19. Gärtner describes a method of producing light for photolithographic systems by using an ignition source (pulsed nitrogen laser 10) to ionize a gas within a "gas-tight chamber 1" that comprises a reflective surface (concave mirror 12). Gärtner then provides energy from a separate laser (CO2 laser 9) to the ionized gas to produce and sustain a plasma that generates high-brightness light. This process directly maps to the method steps recited in claim 19.
    • Key Aspects: The core of this ground is a direct, element-for-element mapping of a single prior art reference that describes the same fundamental technology for the same purpose (photolithography) more than two decades before the ’455 patent’s priority date.

Ground 2: Obviousness of Claims 39-41 - Claims 39-41 are obvious under 35 U.S.C. §103 over Gärtner in view of Ershov.

  • Prior Art Relied Upon: Gärtner (French Patent Publication No. FR2554302A1) and Ershov (Application # 2006/0192152).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Gärtner teaches the fundamental elements of independent claim 39: a light source with a sealed chamber, an ignition source, and an external laser to produce a plasma. The key limitation of claim 39 is a single "curved reflective surface" that both receives and reflects laser energy toward the plasma and receives and reflects the high-brightness light from the plasma toward an output. Petitioner argued that while Gärtner’s various reflectors (e.g., concave mirror 39) inherently perform this dual function, Ershov explicitly discloses such a component to resolve any ambiguity. Ershov’s collector 30 is an elliptical mirror specifically designed to reflect laser energy onto a target to create a plasma and collect the resulting EUV light for output to a lithography tool. The limitations of dependent claims 40 (focusing energy) and 41 (locating the reflector within the chamber) are also explicitly taught by Gärtner and Ershov.
    • Motivation to Combine: A POSITA would combine the teachings because both Gärtner and Ershov address the same problem of creating and efficiently directing light from a laser-sustained plasma for lithography. Ershov teaches an optimized reflector design for this exact purpose. A POSITA would have been motivated to incorporate Ershov’s efficient, well-known elliptical collector design into a system like Gärtner’s to improve the collection and direction of both the sustaining laser energy and the emitted plasma light, which was a known design goal.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because the basic physics of reflecting light and laser energy are universal and well-understood. Combining a known type of reflector (from Ershov) into a known type of plasma light source (from Gärtner) would have involved routine optical design and yielded the predictable result of more efficient light collection.

4. Key Claim Construction Positions

  • "Light source": Petitioner proposed this term be construed broadly to mean "a source of electromagnetic radiation" across the spectrum from extreme ultraviolet to far infrared. This construction is based on the ordinary meaning and the patent's own references to "ultraviolet light," ensuring that prior art generating light in these ranges is not improperly excluded.
  • "High brightness light": Petitioner proposed this term be construed functionally as "light sufficiently bright to be useful for" the applications listed in the ’455 patent, such as semiconductor inspection, lithography, and microscopy. This construction ties the claim term to the purpose disclosed in the specification, preventing the Patent Owner from arguing for a specific, unsupported numerical brightness level that the prior art allegedly fails to meet.

5. Key Technical Contentions (Beyond Claim Construction)

  • Capability of Gärtner's CO2 Laser System: In response to potential arguments from the Patent Owner (raised in related litigation) that Gärtner’s CO2 laser could not produce a "high brightness" light due to creating a large plasma, Petitioner presented a key technical rebuttal. Petitioner argued that plasma brightness is a function of power, gas, and the size of the focal spot, not just the laser wavelength. It contended that the optical system described in Gärtner, using conventional lenses, was fully capable of focusing a CO2 laser beam to a small enough spot size to generate a plasma with a brightness meeting the functional requirements of the ’455 patent’s claims.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 19 and 39-41 of the ’455 patent as unpatentable.