DCT

6:21-cv-00183

Nitride Semiconductors Co Ltd v. Lite On Technolo

Log In

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:21-cv-00183, W.D. Tex., 02/26/2021
  • Venue Allegations: Venue is alleged based on Defendants being registered to do business in Texas and maintaining a regular and established place of business in the Western District of Texas, specifically an office in Austin.
  • Core Dispute: Plaintiff alleges that Defendant’s AlGaN-based ultraviolet (UV) light-emitting diodes (LEDs) infringe a patent covering methods for manufacturing semiconductor devices and the resulting structures.
  • Technical Context: The technology relates to improving the light-emitting efficiency of UV LEDs, which are used in applications such as sterilization and water purification, by creating specific microscopic structures to manage energy conversion.
  • Key Procedural History: The complaint alleges that Defendants had actual notice of the patent-in-suit due to prior litigation Plaintiff filed against Digi-Key Corporation, a distributor, which may form the basis for a willfulness claim. Notably, after this complaint was filed, the U.S. Patent and Trademark Office issued an Inter Partes Review (IPR) Certificate for the patent-in-suit, cancelling independent claims 1 and 8, but confirming the patentability of dependent claims 2 and 9, which were asserted in the complaint. Under U.S. law, these surviving dependent claims are effectively rewritten in independent form, incorporating all limitations of the cancelled parent claims.

Case Timeline

Date Event
2002-03-06 ’270 Patent Priority Date (Filing Date)
2005-03-01 ’270 Patent Issue Date
2020-08-10 Filing date of complaint in prior litigation cited for willfulness
2021-02-26 Complaint Filing Date
2021-07-15 ’270 Patent Inter Partes Review Certificate Issued

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

U.S. Patent No. 6,861,270 - “Method for Manufacturing Gallium Nitride Compound Semiconductor and Light Emitting Element,” issued March 1, 2005

The Invention Explained

  • Problem Addressed: In gallium nitride-based semiconductors, microscopic crystal dislocations cause electrons and holes to recombine without producing light ("non-luminous recombination"), which reduces the device's overall light-emitting efficiency. (’270 Patent, col. 1:20-29).
  • The Patented Solution: The invention intentionally introduces a "spatial fluctuation in the band gap" of the semiconductor material. This is done by forming discrete droplets or a thin film of a "composition material" (e.g., Gallium) on a first semiconductor layer before growing a second, light-emitting layer on top. This material alters the growth of the second layer, creating microscopic regions with a narrower band gap. These engineered regions become highly efficient light-emitting points, effectively outnumbering the efficiency-killing dislocations and thereby increasing the overall light output. (’270 Patent, Abstract; col. 2:48-65; Fig. 1A).
  • Technical Importance: This method provided a way to improve LED efficiency without needing to eliminate the underlying, and difficult to remove, crystal dislocations inherent in the manufacturing process. (’270 Patent, col. 2:1-4).

Key Claims at a Glance

  • The complaint asserts dependent claims 2 and 9. Following an IPR proceeding, parent independent claims 1 and 8 were cancelled. The analysis below presents claims 2 and 9 rewritten in independent form as they now stand for litigation.
  • Independent Claim 2 (Method):
    • A method for manufacturing a gallium nitride based semiconductor, comprising the steps of:
    • (a) forming a first gallium nitride based semiconductor (specifically AlGaN) on a substrate, the first semiconductor having a first surface;
    • (b) forming on less than a total area of the first surface a composition material (specifically one selected from Ga and Al); and
    • (c) forming a second gallium nitride based semiconductor (specifically AlGaN) on the first semiconductor on which the composition material is formed;
    • wherein a spatial fluctuation is created in the band gap by variation in the compositional ratio in the second semiconductor created by the composition material, and the second semiconductor is a light emitting layer.
  • Independent Claim 9 (Apparatus):
    • A light emitting element comprising a gallium nitride based semiconductor, the light emitting element comprising:
    • a substrate;
    • a first gallium nitride based semiconductor layer (specifically AlGaN) formed on the substrate, having a first surface;
    • a composition material (specifically one selected from Ga and Al) formed on less than a total area of the first surface; and
    • a second gallium nitride based semiconductor layer (specifically AlGaN) having a varied compositional ratio and formed on the first semiconductor layer onto which the composition material is formed, where the second semiconductor is a light emitting layer.

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are Lite-On's AlGaN-based UV LEDs and products containing them, specifically including the UVC G35 Series (e.g., LTPL-G35UV275GC-E) and UVA 1616 and 3535 Series (e.g., LTPL-C034UVH365). (Compl. ¶33, ¶38).

Functionality and Market Context

  • The complaint alleges these products are UV LEDs that function as semiconductor light sources. (Compl. ¶39). It provides technical evidence derived from reverse engineering, including Transmission Electron Microscopy (TEM) and Atom Probe Tomography (APT), to describe the microscopic layered structure of the accused LED chips. (Compl. ¶¶41-43). The complaint presents screenshots from what appears to be a distributor website listing various models for sale, suggesting their commercial availability. (Compl. pgs. 7-8). The "Top view of the LED chip" image for the LTPL-G35UV275GC-E shows the physical structure of the accused semiconductor die. (Compl. p. 10).

IV. Analysis of Infringement Allegations

The complaint alleges that the accused LEDs are either made by an infringing process (infringing method claim 2) or have a structure that infringes the apparatus claim (claim 9). The allegations for both claims are based on the same technical evidence derived from analyzing the final products.

’270 Patent Infringement Allegations

Claim Element (from Independent Claim 9) Alleged Infringing Functionality Complaint Citation Patent Citation
a substrate; The complaint alleges the accused LEDs include a substrate, referencing cross-section TEM images showing semiconductor layers formed on a substrate. ¶41 col. 6:18
a first gallium nitride based semiconductor layer [AlGaN] formed on the substrate... having a first surface; The complaint alleges the LEDs comprise a first AlGaN layer formed on the substrate, citing APT data showing a region of aluminum, gallium, and nitrogen. The complaint asserts this layer has a first surface. ¶42 col. 6:20-22
a composition material [of Ga or Al] formed on less than a total area of the first surface; Based on analysis, the complaint alleges a composition material of gallium (Ga) is formed on less than a total area of the first surface. This is supported by an APT-generated "Top View of Ga composition Map" allegedly showing distinct areas of higher Ga concentration. ¶42 col. 6:25-28
a second gallium nitride based semiconductor layer [AlGaN] having a varied compositional ratio... and the second ... layer is a light emitting layer. The complaint alleges the presence of a second AlGaN layer with a varied compositional ratio, citing TEM images and composition maps where varying concentrations of Ga and Al are shown. This layer is alleged to be the light emitting layer. ¶43 col. 6:29-35

Identified Points of Contention

  • Evidentiary Question: The infringement case for the method claim (claim 2) relies entirely on inferring the manufacturing process from the structure of the finished product. A central question will be whether the plaintiff's TEM and APT analysis is sufficient to prove, by a preponderance of the evidence, that Defendants performed the specific claimed steps in the specified order, particularly the step of forming a "composition material" before growing the second layer.
  • Scope Question: Does the term "composition material ... formed on less than a total area," as used in the patent, read on the "areas of higher Ga concentration" shown in the complaint's APT maps? (Compl. p. 12). The defense may argue this claim language requires physically distinct structures, like the "droplets" described in the specification, rather than mere compositional variations within a layer.
  • Causation Question: The claims require that the "spatial fluctuation" or "varied compositional ratio" in the second layer be "created by the composition material." The dispute may focus on whether the plaintiff can prove this causal link, or if the observed variations are an artifact of a different, non-infringing manufacturing process.

V. Key Claim Terms for Construction

  • The Term: "composition material ... formed on less than a total area of the first surface"
  • Context and Importance: This term is the core of the inventive concept. Its construction will determine whether the patent covers only the specific "droplet" embodiment or a broader range of techniques that result in compositional variations. Practitioners may focus on this term because the plaintiff's infringement theory appears to depend on a construction that is broader than the primary embodiment described in the patent.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language itself uses the general term "composition material" rather than limiting it to "droplets." This may support an argument that any discrete region of the specified material meets the limitation, including the high-concentration zones alleged in the complaint. (Compl. ¶42).
    • Evidence for a Narrower Interpretation: The specification repeatedly describes this element as "discrete gallium droplets" or "micro-blocks of gallium." (’270 Patent, col. 3:37-44). Figure 1A, which illustrates the first embodiment, clearly depicts discrete, separate islands (14) on the first layer (12). A defendant could argue these specific disclosures limit the claim scope to such physically distinct structures.

VI. Other Allegations

  • Infringement by Importation (§ 271(g)): The complaint alleges that Defendants infringe under 35 U.S.C. § 271(g) by importing, selling, or using the accused UV LEDs in the U.S., which are alleged to be made by the process claimed in the ’270 patent. The complaint asserts that these products are not materially changed by subsequent processes. (Compl. ¶34, ¶45).
  • Willful Infringement: The complaint alleges willful infringement based on Defendants having had actual notice of the ’270 patent "since at or near the filing date of the First Amended Complaint in Nitride Semicondcutors Co., Ltd. v. Digi-Key Corporation ... (D. Mn. Aug. 10, 2020)." (Compl. ¶55). This allegation aims to establish knowledge of infringement, which could lead to enhanced damages if proven.

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

The resolution of this case appears to hinge on three central questions:

  1. A core issue will be one of claim scope: can the term "composition material," which is described in the patent's preferred embodiment as discrete "droplets," be construed to cover the "areas of higher Ga concentration" that the plaintiff's reverse-engineering evidence allegedly reveals in the accused products?

  2. A key evidentiary question will be one of process inference: can the plaintiff's analysis of the final LED products (via TEM and APT imaging) provide sufficient proof that Defendants necessarily used the patented method, including the sequential step of depositing the "composition material" before growing the final light-emitting layer?

  3. Finally, the case will involve a question of causation: does the evidence demonstrate that the varied composition in the accused LEDs’ final layer was in fact "created by" the alleged "composition material," as required by the claims, or could it have resulted from an alternative, non-infringing manufacturing technique?