DCT

1:26-cv-01256

First Solar Inc v. Ja Solar Technology Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: First Solar, Inc. v. JA Solar Technology Co., Ltd., 1:26-cv-01256, D. Del., 09/28/2026
  • Venue Allegations: Venue is alleged based on the Delaware incorporation of two defendants (JA Solar Industrial and AMPS) and the other defendants' alleged purposeful direction of activities and sales of infringing products into the District of Delaware, establishing a stream of commerce.
  • Core Dispute: Plaintiff alleges that Defendants’ TOPCon solar cells and modules, including the DeepBlue 4.0 and 5.0 series, are manufactured using a process that infringes a patent related to the fabrication of high-efficiency solar cells.
  • Technical Context: The technology at issue is Tunnel Oxide Passivated Contact (TOPCon), an advanced method for manufacturing solar cells that increases energy conversion efficiency compared to conventional designs.
  • Key Procedural History: The complaint alleges that Plaintiff provided Defendants with actual notice of infringement via a letter on September 26, 2024. This followed a July 2024 public announcement by Plaintiff of its TOPCon patent portfolio and intent to enforce. The complaint also notes that Plaintiff filed a related complaint against several JA Solar entities at the U.S. International Trade Commission on February 24, 2026, alleging infringement of the same patent.

Case Timeline

Date Event
2009-04-21 U.S. Patent No. 9,130,074 Priority Date
2015-09-08 U.S. Patent No. 9,130,074 Issue Date
2024-07-19 Plaintiff publicly announced ownership of TOPCon patents
2024-09-26 Plaintiff sent written notice of infringement to Defendant JA Solar
2025 Defendant JA Solar sold former subsidiary AMPS
2026-02-24 Plaintiff filed related complaint at the U.S. International Trade Commission
2026-09-28 Complaint Filing Date

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

U.S. Patent No. 9,130,074 - “High-Efficiency Solar Cell Structures and Methods of Manufacture”

  • Patent Identification: U.S. Patent No. 9,130,074, “High-Efficiency Solar Cell Structures and Methods of Manufacture,” issued September 8, 2015.

The Invention Explained

  • Problem Addressed: The patent background addresses the challenge of creating highly efficient solar cells (≥20%) in a cost-effective and non-complex manner '074 Patent, col. 1:36-42 A key technical problem limiting efficiency in conventional cells is "recombination," where free electrons excited by sunlight are lost at the substrate surface before they can be collected as electrical current Compl. ¶48
  • The Patented Solution: The patent describes a method for manufacturing a solar cell structure that improves efficiency by addressing recombination and conductivity. The method involves depositing an "amorphous interface passivation layer" (e.g., a thin silicon oxide layer) onto a silicon wafer substrate to reduce surface recombination Compl. ¶51 A "conductive and passivating layer" containing a dopant (e.g., phosphorus) is then deposited on top. The entire assembly is subjected to a high-temperature thermal treatment (about 500°C or higher). This heat treatment serves multiple functions: it crystallizes the conductive layer, activates the dopant, and causes the dopant to diffuse through the thin passivation layer and into the substrate '074 Patent, col. 19:24-30 This diffusion creates what the patent calls "shortened charge carrier flow paths," which improve conductivity and allow electrons to travel more directly to the electrodes, thereby increasing the cell’s overall efficiency Compl. ¶55 '074 Patent, col. 19:33-35
  • Technical Importance: This manufacturing process describes the formation of a TOPCon (Tunnel Oxide Passivated Contact) structure, which allows for both excellent surface passivation to minimize electron loss and improved conductivity for efficient charge extraction within a single integrated process Compl. ¶51

Key Claims at a Glance

  • The complaint asserts infringement of independent claim 1.
  • The essential elements of independent claim 1 include:
    • Providing a wafer as a central substrate.
    • Depositing or growing at least one amorphous interface passivation layer over the substrate.
    • Depositing at least one conductive and passivating layer (containing a dopant) on the interface passivation layer.
    • Providing a thermal treatment at about 500° C. or higher to crystallize the conductive layer and facilitate dopant diffusion through the interface layer.
    • Providing metallization (electrodes) that directly contacts the conductive layer, where the diffused dopant provides "shortened charge carrier flow paths" between the substrate and electrodes. Compl. ¶64
  • The complaint also details allegations for dependent claims 2, 4, 5, 7, and 8, and reserves the right to assert additional claims Compl. ¶¶65-69 Compl. ¶102

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are TOPCon solar cells manufactured overseas and the solar modules that incorporate them, including Defendants' "DeepBlue 4.0 and 5.0 series" products Compl. ¶61

Functionality and Market Context

The accused products are described as high-performance solar cells utilizing TOPCon technology to achieve high operational efficiency and superior bifaciality (the ability to generate power from light on both sides of the cell) Compl. ¶5 Compl. ¶85 The complaint alleges these products are made using a manufacturing process that includes depositing a silicon oxide interface passivation layer, depositing a phosphorus-doped silicon film, and applying a thermal treatment that causes the phosphorus to diffuse into the substrate, thereby creating a structure that infringes the ’074 Patent Compl. ¶¶74-80 The complaint includes a Dynamic Secondary Ion Mass Spectrometry (D-SIMS) graph, which it claims shows the chemical composition of the layers in an accused JA Solar TOPCon product Compl. ¶71

IV. Analysis of Infringement Allegations

’074 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
providing a wafer as a central substrate; The accused products are manufactured using a silicon wafer as the central substrate, as allegedly confirmed by D-SIMS analysis showing consistently high silicon levels throughout the bulk of the cell. ¶72 col. 19:17
depositing or growing at least one amorphous interface passivation layer over the substrate; The process allegedly includes depositing an amorphous silicon oxide layer over the substrate. D-SIMS data allegedly shows a spike in oxygen and silicon at the appropriate depth, and the complaint asserts this layer is amorphous as is standard for the chemical vapor deposition (CVD) process. ¶¶73-74 col. 19:18-19
depositing at least one conductive and passivating layer on the at least one interface passivation layer, the at least one conductive and passivating layer comprising a dopant; The manufacturing process allegedly includes depositing an n-type silicon film containing high levels of phosphorus (a dopant) directly behind the interface passivation layer, as shown by D-SIMS testing results. ¶¶75-76 col. 19:20-23
providing thermal treatment at a temperature of about 500° C. or higher, the thermal treatment crystallizing, at least in part, the at least one conductive and passivating layer and facilitating diffusion of the dopant...through the at least one interface passivation layer; The complaint infers this step from D-SIMS data showing significant diffusion of phosphorus from the conductive layer into the central substrate. It alleges this degree of diffusion necessarily requires a thermal treatment above 500°C, which would also cause the conductive layer to crystallize. ¶¶78-80 col. 19:24-30
providing metallization as electrodes which directly contact the at least one conductive and passivating layer...wherein the dopant diffused...provides shortened charge carrier flow paths... The complaint provides a photograph showing metal electrodes on the back of an accused cell Compl. ¶81 It alleges these electrodes make direct contact with the conductive layer and that the phosphorus diffusion shown in the D-SIMS profile results in the claimed "shortened charge carrier flow paths." ¶¶81-83 col. 19:31-35

Identified Points of Contention:

  • Technical Questions: A key point of contention may be the complaint's reliance on indirect evidence. The "thermal treatment" step and its results (crystallization, dopant diffusion) are not directly observed but are inferred from the final product's chemical profile Compl. ¶¶79-80 The litigation may focus on whether the D-SIMS data is sufficient to prove that the accused manufacturing process must have met the specific temperature and functional limitations of the claim.
  • Scope Questions: The final "wherein" clause recites a functional outcome: that the diffused dopant "provides shortened charge carrier flow paths." The complaint alleges this is met by analogy to the patent's figures Compl. ¶83 A dispute may arise over whether this functional language is met, which could require detailed technical analysis of charge transport physics in the accused cells.
  • Scope Questions: The claim requires an "amorphous" interface passivation layer. While the complaint alleges this is an industry standard result of the accused manufacturing process Compl. ¶74, the actual structural state of the layer in the accused product may be a point of dispute and require expert materials analysis.

V. Key Claim Terms for Construction

  • The Term: "amorphous interface passivation layer"

    • Context and Importance: This term defines the structural property of a critical layer in the claimed method. The complaint alleges the accused products are made with such a layer Compl. ¶73 The case's outcome may depend on whether the layer in Defendants' products is properly characterized as "amorphous." Practitioners may focus on this term because the distinction between amorphous, polycrystalline, and crystalline structures is a fundamental and often litigated issue in semiconductor patent cases.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification lists several material examples for this layer, including silicon oxide, silicon nitride, and intrinsic amorphous silicon, suggesting the term is not limited to a single chemical composition '074 Patent, col. 6:60-65
      • Evidence for a Narrower Interpretation: The patent frequently distinguishes between "amorphous" and "polycrystalline" states (e.g., '074 Patent, col. 2:5-7), suggesting "amorphous" should be strictly construed as lacking any crystalline structure. A defendant might argue their layer possesses some degree of crystallinity that removes it from the scope of the term.

  • The Term: "shortened charge carrier flow paths"

    • Context and Importance: This is a functional limitation in the claim's "wherein" clause that describes the result of the dopant diffusion. Proving infringement requires demonstrating that this specific outcome is achieved in the accused process.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent contrasts this concept with a less direct path in a different cell structure, suggesting the term could broadly cover any process that results in a more direct, and thus more conductive, path for charge carriers to the electrode Compl. ¶¶56-57 '074 Patent, col. 5:1-3
      • Evidence for a Narrower Interpretation: The patent describes the "shortened" path in Figure 5 as "the shortest path to the electrodes" '074 Patent, col. 5:1-3, which could be interpreted as a very restrictive requirement. A party could argue that a merely "shorter" path does not meet the inventive concept of the "shortest" path illustrated in the patent.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement under 35 U.S.C. § 271(b), stating that Defendants encourage infringement by their subsidiaries, distributors, and customers through actions such as advertising, providing product manuals and specifications, and offering technical support for the accused products Compl. ¶¶96-97
  • Willful Infringement: Willfulness is alleged based on both pre- and post-suit knowledge of the ’074 Patent. The complaint alleges knowledge from at least September 26, 2024, when First Solar sent a written notice of infringement to JA Solar Compl. ¶98 It also cites a July 2024 press release and a February 2026 ITC complaint as further evidence of knowledge. The complaint alleges that Defendants' continued infringement despite this knowledge is deliberate and willful Compl. ¶100

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

  • 1. Evidentiary Sufficiency: A central issue will be whether Plaintiff's indirect evidence—primarily the D-SIMS chemical profile of the finished product—is sufficient to prove that Defendants perform the specific steps of the claimed method. The case may turn on whether the observed dopant diffusion necessarily proves a thermal treatment at "about 500° C. or higher" and the other functional outcomes required by the claim.
  • 2. Functional Limitation and Infringement: A key battleground will likely be the functional limitation requiring "shortened charge carrier flow paths." The determination of infringement may depend on competing expert testimony regarding the actual charge transport physics within the accused cells and whether this technical reality aligns with the specific function described and claimed in the patent.
  • 3. Claim Construction of "Amorphous": The dispute may hinge on the construction of "amorphous interface passivation layer." The question of whether the relevant layer in Defendants' cells is truly amorphous, or possesses some degree of crystallinity, could be dispositive and will likely be a focus of claim construction proceedings.