DCT

2:24-cv-00262

Maxeon Solar Pte Ltd v. Hanwha Solutions Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:24-cv-00262, E.D. Tex., 04/19/2024
  • Venue Allegations: Plaintiff alleges venue is proper because Defendants are foreign corporations not resident in the U.S. and may be sued in any district. The complaint further alleges Defendants have substantial business contacts within Texas, including directing the construction of a 168-MW solar power plant, selling solar products to Texas customers, and operating a Texas-specific solar credit program.
  • Core Dispute: Plaintiff alleges that Defendant’s solar modules incorporating Tunnel Oxide Passivated Contact (TOPCon) technology infringe three patents related to high-efficiency solar cell structures and fabrication methods.
  • Technical Context: The lawsuit centers on TOPCon solar cells, an advanced photovoltaic technology that has become a key driver of efficiency improvements in the competitive renewable energy market.
  • Key Procedural History: Plaintiff Maxeon is the successor-in-interest to SunPower Corporation, the original patent assignee. The '053 patent is a divisional of the application that led to the '516 patent. The patents-in-suit were assigned from SunPower to Maxeon on December 14, 2022.

Case Timeline

Date Event
2008-02-20 Priority Date for '516 and '053 Patents
2012-07-17 '516 Patent Issued
2014-11-04 '053 Patent Issued
2014-12-22 Priority Date for '315 Patent
2021-01-01 Hanwha announces Q.TRON Series with Q.ANTUM NEO technology
2022-02-15 '315 Patent Issued
2022-12-14 Asserted Patents assigned from SunPower to Maxeon
2024-04-19 Complaint Filed

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

U.S. Patent No. 8,222,516 - “Front Contact Solar Cell with Formed Emitter”

Issued July 17, 2012

The Invention Explained

  • Problem Addressed: The patent seeks to create a relatively efficient and cost-effective front contact solar cell, addressing the general need to improve solar energy conversion and lower manufacturing costs ('516 Patent, col. 1:39-42).
  • The Patented Solution: The invention describes a "bipolar" solar cell structure featuring a backside junction. This is achieved by using an N-type silicon substrate and forming a P-type polysilicon emitter on the backside of the cell, separated by a thin tunnel oxide layer ('516 Patent, Abstract; col. 2:28-34). While the primary junction is on the back, electrical contact is made on both the front (negative polarity) and back (positive polarity), as depicted in the patent's Figure 1 ('516 Patent, col. 2:49-67).
  • Technical Importance: This design architecture aims to capture the high-efficiency potential of backside-junction cells while retaining some of the manufacturing advantages of traditional front-contact cells ('516 Patent, col. 1:35-42).

Key Claims at a Glance

  • The complaint asserts independent claim 9 and dependent claim 10 (Compl. ¶64).
  • Independent claim 9 recites:
    • A solar cell with a front side and a backside.
    • A substrate with a textured front surface.
    • An emitter layer over the back surface of the substrate, forming a backside junction.
    • An oxide layer between the back surface of the substrate and the emitter layer.
    • A first metal contact connected to the substrate on the front side.
    • A second metal contact connected to the emitter layer on the backside, with the two contacts configured to power an external circuit.

U.S. Patent No. 8,878,053 - “Front Contact Solar Cell with Formed Emitter”

Issued November 4, 2014

The Invention Explained

  • Problem Addressed: As a divisional of the '516 patent application, the '053 patent addresses the same general problem of developing cost-effective and efficient solar cell structures and manufacturing processes ('053 Patent, col. 1:41-46).
  • The Patented Solution: The invention focuses on the method of fabricating a solar cell. The key steps involve forming an oxide layer on the back of a silicon substrate, followed by a layer of polysilicon ('053 Patent, col. 8:19-22). The method then calls for diffusing dopants into both the front surface of the substrate and the back-side polysilicon layer to form the necessary electrical junctions, followed by forming the front metal contact ('053 Patent, col. 8:23-33).
  • Technical Importance: The patent highlights the advantage of performing the front-side and back-side diffusion steps "in-situ," meaning within a single furnace load, which "advantageously helps in lowering fabrication cost" ('053 Patent, col. 5:7-14).

Key Claims at a Glance

  • The complaint asserts independent claims 9, 12, 16 and dependent claims 14-15, 17-20 (Compl. ¶81).
  • Independent claim 16 recites a method of fabricating a solar cell, comprising the steps of:
    • Forming an oxide layer over a back surface of a silicon substrate.
    • Forming a layer of polysilicon over the oxide layer.
    • Diffusing dopants into the polysilicon layer to form a backside junction.
    • Diffusing dopants into the front surface of the silicon substrate.
    • Forming a metal contact on the front surface electrically coupled to the substrate.

U.S. Patent No. 11,251,315 - “Solar Cells with Improved Lifetime, Passivation and/or Efficiency”

Issued February 15, 2022

  • Technology Synopsis: This patent addresses the problem of metal impurities within a silicon substrate, which reduce a solar cell's efficiency and electrical lifetime ('315 Patent, col. 5:1-5). The claimed solution is a fabrication method that includes a high-temperature heating step (above 900°C) designed to draw out, or "getter," these impurities from the substrate and trap them in a polysilicon layer, thereby improving the cell's overall performance ('315 Patent, Abstract; col. 5:26-38).
  • Asserted Claims: Independent claim 10 and dependent claims 11, 13-15 (Compl. ¶96).
  • Accused Features: The complaint alleges that Hanwha’s manufacturing process for its Q.ANTUM NEO products, which are based on TOPCon technology, infringes the '315 patent’s method claims (Compl. ¶96, ¶101).

III. The Accused Instrumentality

Product Identification

  • The accused products are Hanwha's solar modules that incorporate its "Q.ANTUM NEO Technology," including but not limited to the Q.TRON solar module series (Compl. ¶59).

Functionality and Market Context

  • The complaint identifies the accused Q.ANTUM NEO technology as being based on a "TOPCon-type cell structure," which stands for Tunnel Oxide Passivated Contact (Compl. ¶13). This technology utilizes an N-type silicon cell and integrates a "NEO Power Transmitter" layer, which is described as a passivating contact that allows for "full area passivation and full area contact at the same time" (Compl. ¶12). This design is alleged to be an improvement over older PERC technology, providing higher power output and efficiency (Compl. ¶5, ¶12). A diagram included in the complaint compares a standard solar cell with one using the accused Q.ANTUM NEO technology, highlighting the "NEO Power Transmitter" as the key differentiating component. (Compl. ¶12, p. 7).
  • The complaint alleges that TOPCon technology has emerged as the "predominant technology for new expansion and replacement of PERC technology" (Compl. ¶5) and that Hanwha holds the leading market share in the U.S. residential and commercial solar markets (Compl. ¶22).

IV. Analysis of Infringement Allegations

'516 Patent Infringement Allegations

Claim Element (from Independent Claim 9) Alleged Infringing Functionality Complaint Citation Patent Citation
a substrate having a textured front surface The accused products use an "n-type" substrate, and the manufacturing process includes a "wafer texturing" step. ¶66 col. 2:35-37
an emitter layer formed over a back surface of the substrate, the emitter layer forming a backside junction with the substrate The accused products' "passivating contact," which is part of the "NEO Power Transmitter" layer, is alleged to be the claimed emitter layer, forming a junction with the n-type substrate. ¶67-68 col. 2:28-34
an oxide layer formed between the back surface of the substrate and the emitter layer The accused products are described as "TOPCon" cells, which by definition include a "Tunnel Oxide" layer between the substrate and the "passivating contact" (the alleged emitter layer). ¶69 col. 2:62-65
a first metal contact making an electrical connection to the substrate on the front side of the solar cell The accused products have "front-side metallization" that makes an electrical connection to the n-type substrate. ¶70 col. 2:49-54
a second metal contact making an electrical connection to the emitter layer on the backside of the solar cell, the first metal contact and the second metal contact being configured to allow... The accused products have "rear-side metallization" that connects to the "passivating contact" (the alleged emitter layer). A product datasheet is cited to show the contacts are configured to power an external circuit. ¶71-72 col. 3:1-10

'053 Patent Infringement Allegations

Claim Element (from Independent Claim 16) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of fabricating a solar cell comprising: forming an oxide layer over a back surface of a silicon substrate The accused products are TOPCon cells, which include a "Tunnel oxide" layer on the back surface of the n-type substrate. ¶84 col. 8:19-20
forming a layer of polysilicon over the oxide layer The accused products have a "passivating contact" over the oxide layer, which is described in technical literature as an "n-polysilicon passivation stack." ¶85 col. 8:21-22
diffusing dopants into the layer of polysilicon to form a backside junction with the silicon substrate The description of the layer as "n-polysilicon" is alleged to indicate that dopants have been diffused into it to form a junction. ¶86 col. 8:23-25
diffusing dopants into a front surface of the silicon substrate... The accused products have a "p+-type emitter" on the front surface, which is alleged to indicate that dopants have been diffused into the front. ¶87 col. 8:26-29
forming a metal contact on the front surface of the silicon substrate...electrically coupled to the...substrate The accused products have "front-side metallization" that is electrically coupled to the n-type substrate. The complaint references a technical diagram showing this structure. ¶88 col. 8:30-33

Identified Points of Contention

  • Scope Questions: A central dispute may concern whether Hanwha's "passivating contact" layer, which is part of its "NEO Power Transmitter," meets the claim definition of an "emitter layer" as recited in the '516 patent. The complaint equates the two, but the primary function of the accused layer (passivation) versus the claimed layer (emitter) may become a point of legal and technical argument.
  • Technical Questions: For the method claims of the '053 and '315 patents, the complaint infers that Hanwha performs the claimed steps based on an analysis of the final product's structure, as shown in a diagram from a "Hanwha Q.ANTUM Neo Analysis" publication (Compl. ¶83, p. 33). A key question for the court will be whether the evidence of the final structure is sufficient to prove that the specific, sequential manufacturing method claimed in the patents was actually used by Hanwha.

V. Key Claim Terms for Construction

  • The Term: "emitter layer" ('516 Patent, claim 9)

    • Context and Importance: This term is critical because the infringement theory hinges on mapping this claim element onto the accused products' "passivating contact" layer. Practitioners may focus on this term because its construction will likely determine whether the core component of Hanwha's TOPCon technology falls within the scope of the patent.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent abstract and summary describe the invention broadly as a "bipolar solar cell" with a "backside junction" formed by a "P-type polysilicon emitter" ('516 Patent, Abstract; col. 2:28-31). A party could argue that any polysilicon layer on the backside that forms the p-n junction functions as the "emitter layer," regardless of its other properties like passivation.
      • Evidence for a Narrower Interpretation: The detailed description consistently refers to the layer as a "P-type doped polysilicon emitter 108" that serves as a "P-type diffusion region" ('516 Patent, col. 2:28-31). A party could argue that the term requires a layer whose primary, defining characteristic is that of an emitter for charge collection, potentially distinguishing it from a layer whose primary purpose is passivation.

  • The Term: "diffusing dopants" ('053 Patent, claim 16)

    • Context and Importance: This is a key action step in the asserted method claim. The interpretation of what constitutes "diffusing" will be important for determining whether Hanwha's manufacturing process infringes.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claim language itself is general and does not specify the mechanism of diffusion. A party could argue this covers any process that causes dopants to move into the silicon or polysilicon layers, including co-deposition or plasma-based techniques.
      • Evidence for a Narrower Interpretation: The specification describes performing the diffusion via a "dopant drive-in step" in a "diffusion furnace" and notes the advantage of performing these steps "in-situ" ('053 Patent, col. 5:7-14). A party could argue that "diffusing" should be construed more narrowly to mean a specific thermal drive-in process, as distinguished from other methods of introducing dopants.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement of the '516 and '315 patents. The factual basis cited includes Hanwha's creation of advertisements, establishment of U.S. distribution channels, and distribution of instructions or manuals for the accused products, which allegedly encourage infringing use (Compl. ¶73, ¶104). The complaint alleges Hanwha has done so with knowledge or willful blindness that the induced acts constitute infringement (Compl. ¶73, ¶104).
  • Willful Infringement: Willfulness is alleged for all three patents. The complaint bases this allegation on continued infringement despite knowledge of the patents, stating that "At a minimum, Hanwha has known of the ['516, '053, and '315] patent at least as early as the filing date of this Complaint" (Compl. ¶74, ¶89, ¶105). This alleges willfulness based on post-suit knowledge.

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

  • A core issue will be one of definitional scope: Can the term "emitter layer," as used in the '516 patent, be construed to read on the "passivating contact" layer that is the central feature of Hanwha's accused TOPCon technology, or is there a fundamental difference in function and structure that places it outside the claim's scope?
  • A key evidentiary question will be one of process versus product: For the '053 and '315 method patents, can Maxeon meet its burden of proving that Hanwha's manufacturing process performs the specific steps claimed, when its initial allegations appear to be based largely on inferences drawn from the final structure of the accused solar cells? The complaint shows an aerial photograph of a large solar power plant in Texas allegedly using Hanwha modules, indicating that the scale of discovery into these manufacturing processes may be substantial (Compl. ¶22, p. 13).