DCT

1:15-cv-13488

SiOnyx LLC v. Hamamatsu Photonics KK

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:15-cv-13488, D. Mass., 11/23/2016
  • Venue Allegations: Venue is alleged to be proper as Defendant Hamamatsu Corp. maintains an office in the District of Massachusetts.
  • Core Dispute: Plaintiffs allege that Defendants’ optoelectronic sensors, which feature enhanced near-infrared sensitivity, infringe patents related to the creation and use of micro-structured silicon, commonly known as "black silicon."
  • Technical Context: The technology involves modifying the surface of silicon wafers with laser pulses to create nano- and micro-scale structures that dramatically increase the material's ability to absorb light, particularly in the near-infrared spectrum.
  • Key Procedural History: The complaint alleges a prior business relationship between SiOnyx and Hamamatsu, initiated in 2006 to explore applying SiOnyx's technology to Hamamatsu's products under a Mutual Non-Disclosure Agreement. After the relationship terminated in 2008, Plaintiffs allege Hamamatsu began selling products and filing patents incorporating the disclosed technology. Subsequent to the filing of this complaint, U.S. Patent No. 7,884,446 was subject to an inter partes review (IPR2016-01143), which resulted in the cancellation of all asserted claims of that patent.

Case Timeline

Date Event
2001-05-25 ’467 Patent Priority Date
2004-09-24 ’446 Patent Priority Date
2006-10-16 SiOnyx initiates relationship with Hamamatsu
2007-01-11 Mutual Non-Disclosure Agreement executed
2008-01-15 Hamamatsu terminates relationship with SiOnyx
2009-09-17 ’591 Patent Priority Date
c. 2010 Hamamatsu allegedly begins selling accused infrared-enhanced devices
2011-02-08 ’446 Patent Issues
2011-12-20 ’467 Patent Issues
2014-03-25 ’591 Patent Issues
2016-06-03 IPR proceeding initiated against ’446 Patent
2016-11-23 Amended Complaint Filed
2020-02-10 IPR Certificate issues, cancelling asserted claims of ’446 Patent

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,884,446 - "Femtosecond Laser-Induced Formation of Submicrometer Spikes on a Semiconductor Substrate"

  • Patent Identification: U.S. Patent No. 7,884,446, "Femtosecond Laser-Induced Formation of Submicrometer Spikes on a Semiconductor Substrate," issued February 8, 2011.

The Invention Explained

  • Problem Addressed: The patent addresses the need for methods to generate surface structures on semiconductors that are smaller than those created by then-existing techniques, specifically aiming for sub-micrometer features (’446 Patent, col. 1:43-46).
  • The Patented Solution: The invention is a semiconductor substrate with a modified surface, or a method for creating it. The method involves irradiating the substrate surface with ultra-short (femtosecond) laser pulses while the surface is in contact with a fluid, such as water (’446 Patent, col. 2:1-6). This process creates a dense field of sub-micron-sized conical "spikes" that alter the material's optical properties (’446 Patent, col. 4:18-34, Fig. 2).
  • Technical Importance: This laser texturing process creates what is known as "black silicon," a material with significantly enhanced absorption of light, particularly at near-infrared wavelengths where normal silicon is relatively transparent (Compl. ¶¶36, 45).

Key Claims at a Glance

  • The complaint asserts independent claim 1 and dependent claims 2-5, 7, and 8 (Compl. ¶¶195-212). It is significant to note that an inter partes review proceeding concluded after the complaint was filed, resulting in the cancellation of claims 1-6 and 11 of the ’446 patent.
  • Independent Claim 1 (Cancelled): A semiconductor substrate comprising:
    • a surface layer having at least a portion exhibiting an undulating topography
    • characterized by a plurality of sub-micron sized features
    • having an average height less than about 1 micrometer
    • and an average width in a range of about 100 nm to about 500 nm.

U.S. Patent No. 8,080,467 - "Silicon-Based Visible and Near-Infrared Optoelectric Devices"

  • Patent Identification: U.S. Patent No. 8,080,467, "Silicon-Based Visible and Near-Infrared Optoelectric Devices," issued December 20, 2011.

The Invention Explained

  • Problem Addressed: The patent identifies the shortcoming of silicon for detecting electromagnetic radiation at long wavelengths (e.g., infrared) due to its electronic band-gap (’467 Patent, col. 1:39-44).
  • The Patented Solution: The invention is a method of fabricating a semiconductor wafer to enhance its infrared sensitivity. The process involves irradiating the silicon surface with short laser pulses while simultaneously exposing it to a substance containing an "electron-donating constituent" (such as sulfur) to create inclusions of that substance in the surface layer. The wafer is then annealed at an elevated temperature to increase the density of charge carriers in that layer (’467 Patent, Abstract; col. 3:9-24).
  • Technical Importance: This combination of laser-induced texturing and chemical doping dramatically improves the responsivity of silicon photodetectors to near-infrared light, enabling lower-cost silicon to be used in applications previously requiring more expensive materials (Compl. ¶¶49-50).

Key Claims at a Glance

  • The complaint asserts independent claim 1 and dependent claims 2, 3, and 11 (Compl. ¶¶221-235).
  • Independent Claim 1: A method of fabricating a semiconductor wafer, comprising:
    • irradiating one or more surface locations of a silicon substrate with a plurality of temporally short laser pulses while exposing said one or more locations to a substance so as to generate a plurality of surface inclusions containing at least a constituent of said substance in a surface layer of said substrate
    • annealing said substrate at an elevated temperature and for a duration selected to enhance a density of charge carriers in said surface layer.

U.S. Patent No. 8,680,591 - "Photosensitive Imaging Devices and Associated Methods" (Multi-Patent Capsule)

  • Patent Identification: U.S. Patent No. 8,680,591, "Photosensitive Imaging Devices and Associated Methods," issued March 25, 2014.
  • Technology Synopsis: This patent describes photosensitive imaging devices that incorporate a "textured region" on a semiconductor substrate. This textured region is positioned to interact with electromagnetic radiation to increase the effective absorption length, particularly for infrared light, thereby improving the device's sensitivity (’591 Patent, Abstract; col. 2:42-49). The patent specifies that the textured region can be formed by processes including lasing and is coupled to a substrate with at least one p-n junction and electrical transfer elements (’591 Patent, col. 18:5-24).
  • Asserted Claims: The complaint asserts independent claim 1 and dependent claims 9 and 24 (Compl. ¶¶244-259).
  • Accused Features: The complaint alleges that Hamamatsu's back-illuminated FFT-CCD image sensors (e.g., S11510 series) infringe by using laser processing to form a textured structure on the backside of the device to improve near-infrared sensitivity (Compl. ¶250).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are infrared-enhanced silicon photodiode and image sensors manufactured and sold by Hamamatsu, including the S11499 and S11510 series sensors (Compl. ¶¶194, 245). The complaint also names end-products that incorporate these sensors, such as the Ocean Optics Maya2000 Pro-NIR spectrometer (Compl. ¶189).

Functionality and Market Context

  • The accused products are described as silicon photodetectors that offer "enhanced near-infrared sensitivity due to a MEMS [micro-electro-mechanical system] structure formed on the back side of the photodiode" (Compl. ¶209, Ex. 23). The complaint alleges this structure is created using Hamamatsu's "unique laser processing technology" (Compl. ¶210, ¶250). The complaint presents a datasheet excerpt from the accused S11499 series, shown in Figure 34, which states that a MEMS structure is formed on the back side of the photodiode to achieve "drastically improved sensitivity in the near infrared region" (Compl. ¶210, Fig. 34). These sensors are alleged to be direct competitors to Plaintiffs' products (Compl. ¶193).

IV. Analysis of Infringement Allegations

’446 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A semiconductor substrate comprising: a surface layer having at least a portion exhibiting an undulating topography The accused Hamamatsu S11499-01 sensor includes a silicon die with a surface layer having a roughened, undulating topography. ¶196-198 col. 2:33-35
characterized by a plurality of sub-micron sized features The surface layer of the accused sensor substrate exhibits sub-micron sized features shown in scanning electron microscope (SEM) images. ¶198 col. 2:35-36
having an average height less than about 1 micrometer SEM image analysis of the accused sensor's substrate allegedly shows that the features have an average height of less than 1 micrometer. ¶199-200 col. 2:36-37
and an average width in a range of about 100 nm to about 500 nm SEM image analysis of the accused sensor's substrate allegedly shows the features have an average width between 100 nm and 500 nm. ¶201-202 col. 2:37-39
  • Identified Points of Contention:
    • Validity and Mootness: The primary point of contention is procedural. The asserted claims of the ’446 patent, including independent claim 1, were cancelled in an inter partes review proceeding that concluded after the filing of the complaint. This raises the question of whether the infringement allegations regarding this patent are moot, as an invalid claim cannot be infringed.
    • Technical Questions: Assuming the claims were valid, a factual question for the court would be whether the complaint's visual evidence, such as the SEM image in Figure 24 showing the "roughened silicon" layer, accurately depicts features that meet the specific dimensional limitations of "average height" and "average width" as defined in the patent (Compl. ¶199, Fig. 24).

’467 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of fabricating a semiconductor wafer, comprising: irradiating one or more surface locations of a silicon substrate with a plurality of temporally short laser pulses Hamamatsu's accused sensors are allegedly produced using a "laser processing technology" involving temporally short laser pulses to create a "MEMS structure." ¶224-226 col. 9:45-51
while exposing said one or more locations to a substance so as to generate a plurality of surface inclusions containing at least a constituent of said substance in a surface layer Upon information and belief, Hamamatsu's laser process exposes the silicon substrate to substances, resulting in the inclusion of constituents such as arsenic, fluorine, nitrogen, phosphorus, and sulfur in the surface layer, as allegedly shown in mass spectrometry profiles. ¶224, ¶226-228 col. 9:48-54
annealing said substrate at an elevated temperature and for a duration selected to enhance a density of charge carriers in said surface layer. Upon information and belief, the silicon substrate is annealed at an elevated temperature to enhance the density of charge carriers, as allegedly evidenced by spreading resistance profiles showing high carrier concentration. ¶229-231 col. 9:55-60
  • Identified Points of Contention:
    • Evidentiary Questions: The complaint alleges the "annealing" step "upon information and belief," supported by graphs showing the resulting charge carrier density in the final product (Compl. ¶229, Fig. 46). A central evidentiary question will be whether discovery confirms that Hamamatsu's manufacturing process actually includes a distinct annealing step performed for the claimed purpose of enhancing charge carrier density, or if the observed electrical properties are a byproduct of a different thermal process.
    • Scope Questions: Does Hamamatsu's use of "laser processing technology" to form a "MEMS structure" meet the claim limitation of irradiating "while exposing...to a substance so as to generate a plurality of surface inclusions"? The complaint infers this connection from the presence of various elements in the final product, as shown in the mass spectrometry graph in Figure 42 (Compl. ¶227, Fig. 42). The case may turn on whether this process mapping is accurate.

V. Key Claim Terms for Construction

  • Term: "annealing said substrate at an elevated temperature and for a duration selected to enhance a density of charge carriers" (’467 Patent, Claim 1)

    • Context and Importance: This term is critical because it requires not only the physical step of annealing but also a specific selection criterion ("selected to enhance...") and a specific outcome ("enhance a density of charge carriers"). The infringement analysis depends on whether Hamamatsu's process meets both the act and the functional purpose defined in this limitation. Practitioners may focus on this term because it links a manufacturing step to its intended technical result, raising questions of both process and intent.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent abstract states the method includes "annealing the substrate...to cause an increase in the charge carrier density." This language could suggest that any annealing step that results in the specified outcome meets the limitation, regardless of the primary purpose for which the step was performed.
      • Evidence for a Narrower Interpretation: The detailed description explains that the annealing step is "designed to cause a rearrangement of the atomic bonds within the...layer to enhance the density of charge carriers" (’467 Patent, col. 11:13-17). This could support a narrower construction requiring that the annealing step be specifically chosen and calibrated for the purpose of improving the electrical properties, not merely an incidental thermal treatment.

  • Term: "textured region" (’591 Patent, Claim 1)

    • Context and Importance: The existence and properties of the "textured region" are central to the infringement allegations for the ’591 patent. The definition will determine whether the "MEMS structure" created by Hamamatsu's laser processing on its accused CCD sensors falls within the scope of the claims.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The summary of the invention states the "textured region can be formed by a variety of processes," including "lasing, chemical etching...nanoimprinting, material deposition, and combinations thereof" (’591 Patent, col. 2:13-17). This broad list suggests the term is not limited to a specific formation method or resulting structure.
      • Evidence for a Narrower Interpretation: The specification describes the textured region as having "surface features having a size selected from the group consisting of micron-sized, nano-sized, and combinations thereof" and lists morphologies like "cones, pillars, pyramids," etc. (’591 Patent, col. 2:5-13). This could support an interpretation requiring discrete, identifiable features rather than just a generally roughened surface.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement of infringement against Hamamatsu. The asserted basis is Hamamatsu's alleged knowledge of the patents-in-suit (from the prior business relationship and citations in its own patent applications) combined with its sale of accused sensors to third parties, such as Ocean Optics, with the knowledge and intent that they would be incorporated into infringing end-products like spectrometers (Compl. ¶189, ¶215, ¶238).
  • Willful Infringement: The complaint alleges willful infringement based on pre-suit knowledge. The basis is twofold: (1) the direct business and technology-sharing relationship between SiOnyx and Hamamatsu from 2006-2008 under an NDA, and (2) Hamamatsu's own patent filings, which allegedly cite Plaintiffs' patents as prior art (Compl. ¶191, ¶217, ¶240).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of historical fact and intent: To what extent does the evidence from the prior business relationship support the narrative that Hamamatsu derived its accused "black silicon" technology from confidential information disclosed by SiOnyx? The answer will be central to the claims of willful infringement and may influence the interpretation of technical evidence.
  • A key evidentiary question will be one of process mapping: Does discovery confirm that Hamamatsu's manufacturing process includes the specific, multi-part method steps recited in the ’467 patent—namely, laser irradiation while exposing to a substance to generate inclusions, followed by an annealing step selected to enhance charge carrier density—or is there a fundamental mismatch between the claimed method and the accused process?
  • A dispositive legal question will be one of validity and claim scope: Given the post-filing cancellation of the asserted claims of the ’446 patent in an IPR, the infringement analysis will likely focus entirely on the remaining ’467 and ’591 patents. For those patents, the dispute may turn on the construction of key terms like "annealing...selected to enhance" and "textured region," and whether Hamamatsu's accused MEMS structures fall within their scope.