August 22, 2019

Patent Directed to Testing Electronic Circuits Using a Laser Beats § 101 Challenge

Holland & Knight Section 101 Blog
Anthony J. Fuga

Plaintiff SEMICAPS filed suit in the Northern District of California, alleging infringement of U.S. Patent No. 7,623,982, which relates to the testing of electronic circuits using a laser. The defendants moved to dismiss the complaint, arguing that the asserted claims are invalid because they claim patent-ineligible subject matter.

The '982 Patent

The asserted patent relates to testing an electronic circuit in order to determine the location of defects on a semiconductor circuit. SEMICAPS explained that newly-fabricated integrated semiconductor circuits are typically tested by connecting them to electronic test equipment. Output signals can reveal defects, but will not identify the location of such a defect. There were also conventional laser induced techniques to stimulate integrated circuit failures, which are sensitive to thermal or carrier stimulation. But these conventional laser techniques, according to SEMICAPS and the patent specification, have not been successful because the required increase in laser power could induce damage on the circuit.

Accordingly, the '982 attempted to increase detection sensitivity in a laser-based fault detection system without increasing the power of the laser beam, along with overcoming other shortfalls of the conventional laser technique. The claimed method "comprises radiating a laser beam onto the electronic circuit, and determining a plurality of samples of a response signal output by the electronic circuit during the period when the laser beam is radiated."

A signal processor processes sample measurements of the response signal and then generates a test result based on the value generated. Based on that generated value, a fault on the electronic circuit may appear as a bright spot, bright line, or bright area at a pixel location corresponding to the location of the fault on the circuit.

The Defendants' Motion and the Court's Analysis

The defendants argued that the asserted claims were directed to the abstract idea of collecting data and processing that data to generate a test result, similar to the abstract idea seen in Electric Power. Additionally, the defendants argued, the inclusion of hardware and computer components did not change the abstract form of what was claimed.

SEMICAPS, on the other hand, argued that the claims are directed to a specific technological advancement – namely, "improving fault detection sensitivity in laser-based testing of integrated circuits."

The court agreed with SEMICAPS and found that the defendants' characterization of the patent claims was "overly reductive" and ignored the technical context of the patent and the claimed improvements over prior art:

The '982 patent explains how advancements in integrated circuits, including the use of more metallization layers and materials with lower thermal conductivity, have resulted in the need for increased fault detection sensitivity. It describes the problems inherent with existing approaches and sets forth a new system for testing integrated circuits that enables the detection of otherwise undetectable response signals.

. . .

[The claims] claim a step-by-step method to improve an existing technological process by which previously undetectable response signals may be detected and analyzed to pinpoint the location of a fault on an electronic circuit.

The court also differentiated SEMICAPS' patent from the patent claims in Electric Power. In Electric Power, the claims were based upon accumulating existing data from disparate sources, analyzing it, and displaying the results. But in this case, the court found that the method was not directed to merely collecting readily observable data but a method of detecting response signals that are "otherwise undetectable using prior art methods."

Because the claims focus on a specific method "that improves the relevant technology" and are, therefore, directed to patent-eligible subject matter under § 101, the court declined to proceed to step two of the Alice inquiry and denied the defendants' motion to dismiss.

Claim 1 of the asserted patent is below:

A method of testing an electronic circuit, comprising:

radiating a laser beam onto the electronic circuit,

determining a plurality of samples of a response signal output by the electronic circuit during the period when the laser beam is radiated,

accumulating the plurality of samples to generate a value, and generating a test result based on the value.

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