DCT
8:23-cv-02068
VisionX Tech LLC v. OmniVision Tech Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: VisionX Technologies, LLC (Texas)
- Defendant: OmniVision Technologies Inc. (Delaware)
- Plaintiff’s Counsel: One LLP
- Case Identification: 8:23-cv-02068, C.D. Cal., 11/02/2023
- Venue Allegations: Plaintiff alleges venue is proper because Defendant is subject to personal jurisdiction in the district and maintains offices in Irvine, California, where a substantial portion of the alleged infringing activities occurred.
- Core Dispute: Plaintiff alleges that Defendant’s stacked CMOS image sensors infringe three patents related to the vertical integration of sensor components and methods for their manufacture.
- Technical Context: The technology concerns advanced semiconductor image sensors, a critical component in high-demand markets including smartphones, automotive systems, and medical imaging, where performance and miniaturization are paramount.
- Key Procedural History: The complaint notes that the Asserted Patents were originally issued to Dongbu HiTek Co., Ltd., and have since been assigned to Plaintiff VisionX.
Case Timeline
| Date | Event |
|---|---|
| 2007-03-14 | Earliest Priority Date for ’366 Patent |
| 2007-12-28 | Earliest Priority Date for ’808 Patent |
| 2008-11-05 | Earliest Priority Date for ’143 Patent |
| 2011-01-11 | ’808 Patent Issued |
| 2011-01-11 | ’366 Patent Issued |
| 2011-10-11 | ’143 Patent Issued |
| 2023-11-01 | Alleged Date of Defendant's Knowledge |
| 2023-11-02 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,867,808 - “Image Sensor and Method for Manufacturing the Same,” issued January 11, 2011 (’808 Patent)
The Invention Explained
- Problem Addressed: The patent’s background section describes challenges in conventional Complementary Metal Oxide Silicon (CMOS) image sensors where the photodiode and processing transistors are arranged horizontally on a substrate. This arrangement forces a trade-off: increasing pixel size to improve sensitivity reduces overall image resolution, while shrinking pixel size for higher resolution can degrade sensor sensitivity (’808 Patent, col. 1:11-44).
- The Patented Solution: The invention discloses a method for vertically integrating the sensor’s components. A first substrate containing the processing circuitry is manufactured separately from a second substrate containing the light-capturing photodiode. The two substrates are then bonded together, creating a stacked structure that allows for a larger photodiode area within a smaller pixel footprint (’808 Patent, Abstract; col. 2:5-11). The patent also describes using an ion implantation isolation layer to insulate pixels from each other, which it states can be used instead of a conventional shallow trench isolation (STI) process to minimize defects (’808 Patent, col. 2:54-62).
- Technical Importance: This vertical stacking approach allows for the independent optimization of the photodiode and the logic circuitry, enabling the fabrication of image sensors with both high resolution and high sensitivity (’808 Patent, col. 1:45-51).
Key Claims at a Glance
- The complaint asserts independent method claim 1 (Compl. ¶22).
- Essential elements of claim 1 include:
- Providing a first substrate and forming circuitry with a metal interconnection over it.
- Forming a photodiode in a crystalline semiconductor layer of a second substrate.
- Forming a specific, multi-part ion implantation isolation layer in the photodiode.
- Bonding the first substrate to the second substrate to connect the photodiode to the metal interconnection.
- Removing a lower portion of the second substrate to expose the photodiode.
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 8,035,143 - “Semiconductor Device and Method for Manufacturing the Same,” issued October 11, 2011 (’143 Patent)
The Invention Explained
- Problem Addressed: The patent identifies light loss and degraded sensitivity in image sensors where light must travel through multiple layers of metal interconnections on the front of the sensor to reach the photodiode (’143 Patent, col. 1:33-43).
- The Patented Solution: The invention describes a backside-illuminated (BSI) image sensor architecture. A "connection via metal" is formed to extend from the first (front) surface through the semiconductor substrate to the second (back) surface. A portion of this via metal projects from the second surface, creating a "projection part." A metal pad is then formed on an insulating layer over this projection part, creating an external contact point on the sensor's backside (’143 Patent, Abstract; col. 2:5-15). This structure allows light to enter from the backside, providing an unobstructed path to the photodiode.
- Technical Importance: BSI technology represents a significant advancement by decoupling the light path from the electronic wiring path, thereby increasing the amount of light collected (quantum efficiency) and dramatically improving sensor performance, especially in low-light conditions (’143 Patent, col. 1:39-47).
Key Claims at a Glance
- The complaint asserts independent apparatus claim 1 (Compl. ¶44).
- Essential elements of claim 1 include:
- A semiconductor substrate with readout circuitry and a photodiode area on a first surface.
- A metal interconnection layer on the first surface.
- A connection via metal extending from the first to a second surface, having a "projection part" that projects from the second surface.
- An insulating layer on the second surface that exposes the projection part while surrounding a portion of its lateral side.
- A metal pad on the insulating layer that covers the projection part.
- A dimensional requirement: the insulating layer must have a thickness thinner than the projection height of the projection part.
- The complaint notes it is investigating whether other products infringe additional claims (Compl. ¶41, n.27).
U.S. Patent No. 7,868,366 - “Image Sensor and Method for Fabricating the Same,” issued January 11, 2011 (’366 Patent)
- Technology Synopsis: This patent addresses the design limitations imposed by metal interconnections in increasingly small pixels (’366 Patent, col. 1:22-28). The invention is an image sensor constructed by bonding a first semiconductor substrate (containing the pixel array) to a second semiconductor substrate (containing logic circuitry). It claims a specific arrangement of vias, pre-metal dielectrics, and interlayer dielectrics that connect the two substrates, aiming to enhance optical characteristics and improve fabrication (’366 Patent, Abstract; col. 1:40-50).
- Asserted Claims: The complaint asserts independent apparatus claim 1 (Compl. ¶63).
- Accused Features: The complaint alleges that Defendant's "stacked" products, such as the OmniVision OV23850, infringe by embodying the claimed structure of two bonded substrates connected by a specific configuration of vias and dielectric layers (Compl. ¶60, 62, 64).
III. The Accused Instrumentality
Product Identification
- The complaint identifies Defendant’s "PureCel-S," "PureCel Plus-S," and "stacked" product lines as infringing (Compl. ¶18, 60). Specific accused products include, but are not limited to, the OmniVision OV60A, OV50A, and OV23850 image sensors (Compl. ¶18, 21, 41, 43, 60, 62).
Functionality and Market Context
- The accused products are described as stacked image sensors, which are composed of a CMOS Image Sensor (CIS) die vertically bonded to an Image Signal Processor (ISP) die (Compl. ¶23, 45). The complaint provides a scanning electron microscope (SEM) image showing the cross-section of a stacked CIS and ISP in the accused OV60A product (Compl. ¶23, Figure 1). The complaint alleges these sensors are key components in a wide range of electronic devices, including smartphones, automotive systems, virtual reality (VR) headsets, and medical imaging equipment (Compl. ¶8, 55).
IV. Analysis of Infringement Allegations
’808 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| providing a first substrate; | The accused OV60A sensor provides an Image Signal Processor (ISP) substrate, which is alleged to be the "first substrate." (Compl. p. 11). | ¶27 | col. 2:26-30 |
| forming circuitry including a metal interconnection over the first substrate; | Circuitry, including multiple metal interconnection layers (e.g., ISP M1-M6 Cu), is formed over the ISP substrate. (Compl. p. 12). | ¶27 | col. 2:6-7 |
| forming a photodiode in a crystalline semiconductor layer of a second substrate; | A photodiode is formed in a crystalline semiconductor layer of a CMOS Image Sensor (CIS) substrate, which is the "second substrate." The complaint provides a scanning capacitance microscope (SCM) cross-section of the pixels. (Compl. ¶25; p. 13). | ¶27 | col. 3:4-10 |
| forming an ion implantation isolation layer in the photodiode; | An isolation layer of P-type impurity ions is formed in the photodiode, allegedly including deep trench isolation structures. | ¶27 | col. 2:31-34 |
| bonding the first substrate to the second substrate to connect the photodiode to the metal interconnection; | The ISP (first) and CIS (second) substrates are bonded together to connect the photodiode to the metal interconnections of the ISP substrate. | ¶27 | col. 4:12-18 |
| and removing a lower portion of the second substrate to expose the photodiode, | A lower portion of the CIS substrate is removed to expose the photodiode, as illustrated by a dashed red line in an SEM image. (Compl. p. 16). | ¶27 | col. 4:38-44 |
| wherein forming the photodiode comprises: forming a second conduction type conduction layer in the crystalline semiconductor layer; and forming a first conduction type conduction layer over the second conduction type conduction layer, | The photodiode is formed using a P-type conduction layer (alleged second type) and an N-type conduction layer (alleged first type) situated over the P-type layer. | ¶27 | col. 2:35-39 |
- Identified Points of Contention:
- Scope Questions: The complaint accuses the OmniVision OV60A Image Sensor (an apparatus) of infringing a method claim. While the complaint alleges that Defendant "makes" the infringing products (Compl. ¶17), a point of contention will be whether Plaintiff can prove that Defendant itself performs every step of the claimed manufacturing method, in the order recited.
- Technical Questions: A key technical question will be whether the accused product's isolation structures, which the complaint identifies as "P-type isolation layers and back deep trench isolation (B-DTI)" (Compl. ¶25, Fig. 3), meet the specific two-part definition of the "ion implantation isolation layer" required by the sub-elements of claim 1.
’143 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a semiconductor substrate formed on a first surface thereof with a readout circuitry and a photodiode area; | The accused OV50A's CIS substrate has a first surface with a pixel array of photodiodes and corresponding readout circuitry. (Compl. p. 25). | ¶46 | col. 2:6-8 |
| a metal interconnection layer formed on the first surface; | A metal interconnection layer is situated on the first surface of the CIS substrate. | ¶46 | col. 2:8-9 |
| a connection via metal extending from the first surface to a second surface of the semiconductor substrate, the connection via metal having a projection part projecting from the second surface; | A copper connection via metal extends from the first surface to the second surface of the CIS substrate. A portion of this via projects from the second surface, forming the alleged "projection part." The complaint provides a colored SEM image to illustrate this structure. (Compl. p. 27). | ¶46 | col. 2:9-12 |
| an insulating layer formed on the second surface of the semiconductor substrate to expose the projection part while surrounding a portion of a lateral side of the projection part; | An insulating layer is formed on the second surface, leaving some of the projection part exposed while surrounding a portion of its side. | ¶46 | col. 2:12-14 |
| and a metal pad formed on the insulating layer such that the metal pad covers the projection part, | A metal pad at ISP metal level seven (M7) is situated on the insulating layer and covers the projection part. | ¶46 | col. 2:14-15 |
| wherein the insulating layer has a thickness thinner than a projection height of the projection part. | The complaint alleges that the thickness of the insulating layer is less than the height of the projection part, providing a diagram to illustrate the relative dimensions. (Compl. p. 30). | ¶46 | col. 2:15-17 |
- Identified Points of Contention:
- Scope Questions: The definition of "projection part" will be critical. The dispute may center on whether the feature identified in the accused product constitutes a "projection" as contemplated by the patent, or if it is merely a flush or co-planar via connection that resulted from a different manufacturing process.
- Technical Questions: The final limitation requires a specific dimensional relationship: the insulating layer must be "thinner than a projection height of the projection part." This creates a clear factual question that will depend on measurements from technical analysis of the accused products. The complaint's visual assertion of this relationship (Compl. p. 30) will be tested against Defendant's own evidence.
V. Key Claim Terms for Construction
’808 Patent
- The Term: "ion implantation isolation layer"
- Context and Importance: This term is central to how the patented method isolates individual pixels. The claim further defines this layer as being formed through two specific sub-steps. Practitioners may focus on this term because its construction will determine whether the accused product's combination of P-type isolation and deep trench isolation (B-DTI) falls within the claim's scope.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification suggests the invention can be used "instead of using a related art shallow trench isolation (STI) process," which could support an argument that the term encompasses various non-STI isolation techniques that use ion implantation (’808 Patent, col. 2:57-59).
- Evidence for a Narrower Interpretation: The claim itself breaks this element into two distinct sub-elements: forming a "first ion implantation isolation layer" over a conduction layer and a "second ion implantation isolation layer" at the pixel interface (’808 Patent, col. 6:1-8). The patent figures also depict specific "PO layer 220a" and "PO layer 220b" structures, which could be used to argue for a more limited construction tied to that specific embodiment (’808 Patent, Fig. 1; col. 3:45-61).
’143 Patent
- The Term: "projection part"
- Context and Importance: This structural feature is the core of the BSI connection method described in the patent. The infringement analysis for the apparatus claim hinges on identifying a corresponding physical structure in the accused device. Its "projection height" is also an explicit limitation in the claim.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes this feature as the result of a process: a portion of the "connection via metal" projects from the surface after a grinding process (’143 Patent, col. 2:9-12). This process-based description could support a broader definition that includes any structure resulting from such a process, regardless of its precise shape.
- Evidence for a Narrower Interpretation: The patent abstract and summary repeatedly refer to the structure as a "projection part projecting from the second surface," and the figures depict a distinct, pillar-like structure (’143 Patent, Abstract; Fig. 4, element 125a). This could support an argument that the term requires a structure that is intentionally formed to extend significantly beyond the substrate surface, not one that is merely non-planar or flush.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement for all three patents. The allegations are based on Defendant selling the accused image sensors to downstream manufacturers (e.g., Microsoft, Dell, Tesla) and providing "specifications and promotional literature," user manuals, and technical support that allegedly instruct and encourage customers to incorporate the sensors into infringing end-user products like smartphones and vehicles (Compl. ¶29-30, 34, 48-49, 53, 68-69, 73).
- Willful Infringement: The complaint alleges willful infringement for all three patents. The basis for willfulness is that Defendant had "actual knowledge" of the patents and their infringement "at least as of November 1, 2023"—one day prior to the complaint's filing—and also as of the date of the complaint itself (Compl. ¶31-32, 50-51, 70-71). This pleading strategy preserves a claim for willfulness based on both pre-suit and post-suit conduct.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of evidentiary proof for method claims: For the ’808 patent, which contains method claims, a central challenge for the Plaintiff will be to produce sufficient evidence demonstrating that Defendant OmniVision performs all the recited manufacturing and processing steps, in the claimed sequence, to create the accused sensors.
- A key battleground will be one of claim construction and structural correspondence: For the apparatus claims of the ’143 and ’366 patents, the outcome will likely depend on the court’s construction of critical structural terms like "projection part" (’143 Patent) and the specific via and dielectric layer arrangements (’366 Patent). The dispositive question will then be whether the physical architecture of the accused OmniVision sensors, as revealed through technical analysis, meets these construed limitations, especially the relative dimensional requirements.
- A determinative question for damages will be the timing and nature of knowledge: The complaint alleges Defendant had knowledge of the patents just one day before the suit was filed. The case will explore what notice, if any, was provided and when, as this will be critical to establishing the requisite knowledge and intent for willful infringement and any potential for enhanced damages.