Hamamatsu Photonics KK v. SemiCapS Pte Ltd

1. Case Identification

• Case #: IPR2017-02110
• Patent #: 7,623,982
• Filed: September 15, 2017
• Petitioner(s): Hamamatsu Photonics K.K.
• Patent Owner(s): Semicaps Pte Ltd.
• Challenged Claims: 1, 4-7, and 21-25

2. Patent Overview

• Title: Method and Apparatus for Testing an Electronic Circuit
• Brief Description: The ’982 patent discloses a method and corresponding apparatus for testing an electronic circuit to identify faults. The technology involves radiating a laser beam onto the circuit, determining a plurality of samples from the resulting response signal during the laser radiation period, accumulating the samples to generate a single value, and then generating a test result based on that value to improve detection sensitivity.

3. Grounds for Unpatentability

Ground 1: Claims 1, 21, and 22 are anticipated by Hamada under 35 U.S.C. §102.

• Prior Art Relied Upon: Hamada (Japanese Publication No. 2003-1719108A).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Hamada, which describes an inspection device for semiconductor devices, discloses every limitation of independent claims 1 (method) and 21 (apparatus). Hamada’s system uses an optical beam (disclosed as a laser) to irradiate a device under test (DUT), measures an operation current with an electrical current meter, and uses a signal processing unit to calculate an average current. Petitioner contended that the explicit disclosure of calculating an "average current" at each test site inherently requires determining a plurality of samples and accumulating them (by adding) to generate a value, thereby meeting the key limitations the patentee relied on for patentability during prosecution. For dependent claim 22, Hamada's disclosure of scanning and irradiating multiple distinct sites (1, 2, and 3) teaches moving the laser source according to a pattern.

Ground 2: Claims 1, 4-7, 21, and 23-25 are anticipated by Quah under §102.

• Prior Art Relied Upon: Quah (a 2006 conference proceeding titled “DC-Coupled Laser Induced Detection System for Fault Localization in Microelectronic Failure Analysis”).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Quah, a publication by four of the five inventors of the ’982 patent, anticipates all challenged claims. Quah describes a laser-induced detection system that scans a laser across a DUT, digitizes the "laser induced signal response," and incorporates "signal averaging" to improve the signal-to-noise ratio. Petitioner argued that "digitization" and "signal averaging" inherently teach determining and accumulating a plurality of samples. Furthermore, Quah's disclosure of laser dwell times per pixel was used to calculate laser pulse frequencies (0.5 kHz to 10 kHz), while its disclosure of a 20 MHz sampling frequency for a converter was argued to anticipate the dependent claims relating to pulsed lasers and specific frequency relationships.

Ground 3: Claims 4, 5, 7, 23, and 24 are obvious over Hamada in view of Beaudoin under §103.

• Prior Art Relied Upon: Hamada (Japanese Publication No. 2003-1719108A) and Beaudoin (a 2003 article titled “From Static Thermal and Photoelectric Laser Stimulation (TLS/PLS) to Dynamic Laser Testing”).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground asserted that if Hamada was found not to teach a pulsed laser, it would have been obvious to modify Hamada’s system using the teachings of Beaudoin. Hamada provides the base system for laser-based circuit testing. Beaudoin teaches using either a continuous or a pulsed laser for similar electronic circuit testing and analysis.
  • Motivation to Combine: A POSITA would combine these references because Beaudoin explicitly taught that using a pulsed laser provides several known advantages over a continuous wave laser for this application, including improved signal-to-noise ratio, the ability to detect fainter signals, and a reduction in thermal damage risk to the circuit.
  • Expectation of Success: A POSITA would have had a high expectation of success because the combination involved substituting a well-known component (a pulsed laser source) into a conventional testing system (Hamada's) to achieve predictable and well-documented benefits. Beaudoin’s disclosure of a 100 kHz maximum modulation frequency, combined with Hamada’s 1-100 MHz sampling frequency, rendered the frequency limitations of claims 5, 7, and 24 obvious.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 4-7 and 22-25 are obvious over Hamada in view of Bruce, and that claims 4-7 and 23-25 are obvious over Hamada in view of Quah. Petitioner also presented alternative obviousness arguments over Hamada alone and Quah alone.

4. Key Claim Construction Positions

• "accumulating" / "accumulates": Petitioner argued this term should be construed to mean "adding or performing any act that includes adding as a step, such as averaging." This construction was critical to its anticipation and obviousness arguments, as the primary prior art references (Hamada and Quah) explicitly disclose "averaging" signals, which Petitioner equated to the claimed "accumulating" step.
• "to dwell on a location": Petitioner proposed this term be construed as "to radiate a location (or each of a plurality of locations) on the electronic circuit for a duration of time." This construction allowed Petitioner to map the prior art's descriptions of laser scanning systems, which irradiate successive pixels or sites for a set time, directly onto the claim language.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1, 4-7, and 21-25 of Patent 7,623,982 as unpatentable.