Advantest Test Solutions Inc v. Aem Holdings Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Advantest Test Solutions, Inc. (Delaware)
  • Defendant: Aem Holdings Ltd. (Singapore); Aem Singapore Pte. Ltd. (Singapore); and Aem Americas, Inc. (California)
  • Plaintiff's Counsel: Davis Polk & Wardwell LLP; Gish PLLC
• Case Name: Advantest Test Solutions, Inc. v. Aem Holdings Ltd.
• Case Identification: 3:25-cv-02604, S.D. Cal., 07/20/2026
• Venue Allegations: Venue is alleged to be proper in the Southern District of California because Defendant AEM Americas, Inc. is a California corporation with its headquarters in San Diego, which resides within the district.
• Core Dispute: Plaintiff alleges that Defendants' semiconductor wafer testing products infringe two patents related to active thermal control technology, which was allegedly developed at Plaintiff by a former executive who is now Defendants' CEO.
• Technical Context: The technology involves systems for precisely heating and cooling different zones of a semiconductor wafer during testing to verify chip performance under various temperature conditions before the wafer is diced into individual chips.
• Key Procedural History: The complaint alleges that the parties previously engaged in an arbitration concerning misconduct by the former executive, which resulted in a $20 million settlement payment from AEM to Advantest.

Case Timeline

Date	Event
2019-11-01	Samer Kabbani begins overseeing development of thermal products at Advantest.
2019-12-01	Kabbani presents "wafer probe ATI" idea to Advantest's German affiliate.
2020-01-01	Technical specifications for "wafer ATI" project completed.
2020-03-01	Advantest's board approves funding to commercialize the technology.
2020-07-15	Kabbani is placed on administrative leave by Advantest.
2020-08-01	Kabbani joins AEM as Chief Technology Officer.
2020-11-19	Priority date for '999 and '841 Patents (filing of '813 Provisional).
2021-11-16	Application for '841 Patent filed.
2022-04-20	Application for '999 Patent filed.
2023-06-13	U.S. Patent No. 11,674,999 issues.
2024-06-01	AEM representatives allegedly offer to sell accused products to Intel.
2025-06-03	U.S. Patent No. 12,320,841 issues.
2025-10-01	Plaintiff files initial complaint in the action.
2026-07-20	First Amended Complaint for Patent Infringement filed.

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

U.S. Patent No. 11,674,999 - "Wafer Scale Active Thermal Interposer for Device Testing"

The Invention Explained

• Problem Addressed: The patent's background describes the limitations of traditional environmental testing for semiconductor devices, noting that large test chambers are slow and that newer "chamber-less" systems have difficulty precisely heating and cooling individual areas of a full wafer '999 Patent, col. 1:36-2:15
• The Patented Solution: The invention is a system that combines a "wafer thermal interposer (TI) layer" positioned against the wafer to selectively heat specific areas, a "cold plate" disposed underneath the TI layer to provide cooling, and a "thermal controller" that coordinates the heating and cooling operations '999 Patent, abstract '999 Patent, FIG. 1 This arrangement allows for precise, zoned temperature control across the wafer during testing '999 Patent, col. 2:30-44
• Technical Importance: This approach allows for rapid, precise, and independent thermal testing of multiple dice or regions on a single wafer before it is cut, which can increase manufacturing throughput and improve reliability verification '999 Patent, col. 2:5-15

Key Claims at a Glance

• The complaint asserts infringement of at least independent claim 1 ('999 Patent, Compl. ¶75).
• The essential elements of independent claim 1 include:
  • A tester system for generating and processing test signals.
  • A test stack comprising:
    • A wafer probe for contacting a first surface of the wafer.
    • A wafer thermal interposer (TI) layer operable to contact a second surface of the wafer and selectively heat areas.
    • A cold plate disposed under the TI layer to cool the wafer.
  • A thermal controller for selectively heating and maintaining temperatures by controlling the cooling of the cold plate and the heating of the TI layer.
  • A pin lift mechanism for lifting the wafer, with alignment holes through the cold plate and TI layer.
• The complaint reserves the right to assert other claims ('999 Patent, Compl. ¶75).

U.S. Patent No. 12,320,841 - "Wafer Scale Active Thermal Interposer for Device Testing"

The Invention Explained

• Problem Addressed: As with the '999 Patent, the '841 Patent addresses the need for precise, wafer-level environmental testing that is more efficient than traditional methods '841 Patent, col. 1:19-2:15
• The Patented Solution: The '841 Patent discloses the same fundamental system architecture as the '999 Patent, comprising a thermal interposer for heating, a cold plate for cooling, and a controller for coordination '841 Patent, abstract '841 Patent, FIG. 1 This patent more specifically claims the thermal interposer as comprising a "plurality of resistive traces" that are used to heat different zones of the wafer '841 Patent, col. 2:48-56
• Technical Importance: By specifying the use of resistive traces, the invention provides a concrete mechanism for achieving the zoned heating necessary for efficient, parallel, multi-site testing on a single semiconductor wafer.

Key Claims at a Glance

• The complaint asserts infringement of at least independent claim 1 ('841 Patent, Compl. ¶91).
• The essential elements of independent claim 1 include:
  • A test computer for testing circuits on a wafer.
  • A wafer probe for contacting a first surface of the wafer.
  • A wafer thermal interposer (TI) layer comprising a "plurality of resistive traces" operable to selectively heat a "plurality of zones."
  • A cold plate disposed adjacent to the TI layer to cool the wafer.
  • A thermal controller for selectively heating and maintaining temperatures by controlling the cold plate and the "selective heating of said plurality of resistive traces."
• The complaint reserves the right to assert other claims ('841 Patent, Compl. ¶91).

III. The Accused Instrumentality

Product Identification

The complaint identifies the "Accused Products" as the combination of Defendants' "Thermal Control Wafers" (TCWs) with their wafer probe test systems, including but not limited to the "MPP Multi Purpose Frame/Wafer Probe System," "KRONOS Inertial Sensor Wafer Probe System," and "AIOLOS Pressure Sensor Test System" Compl. ¶51 The technology is also allegedly marketed under the "PiXL" brand Compl. ¶46

Functionality and Market Context

• The complaint alleges that the Accused Products are used for wafer-level semiconductor testing and embody the technology disclosed in what Plaintiff terms AEM's "Copycat Patents" Compl. ¶¶41-42 Compl. ¶50 These products are alleged to provide "multi-zone thermal control" during wafer probe testing Compl. ¶46 The complaint includes a marketing image from Defendants' website for the "MPP Multi Purpose Frame/Wafer Probe System," which states the platform "offers a range of temperature options that allows testing at automotive grade temperature levels" Ex. J, p. 3
• The complaint alleges that Defendants market this technology as a "patented, intelligent thermal management technology that provides rapid, precise control of test environments" and is "uniquely integrated across all test insertions" Compl. ¶46 The primary customer for these products is alleged to be Intel Corporation Compl. ¶53

IV. Analysis of Infringement Allegations

'999 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a wafer thermal interposer (TI) layer operable to contact a second surface of said wafer and operable to selectively heat areas of said wafer	The complaint alleges infringement through Defendants' "Thermal Control Wafer" (TCW), which is described in AEM's own '885 patent as comprising heaters with resistive traces that emit thermal energy to heat a wafer under test Compl. Ex. I, pp. 15-16	¶78	col. 2:36-39
a cold plate disposed under said wafer TI layer and operable to cool said wafer	AEM's '885 patent, cited as evidence, allegedly discloses a "coldplate 232" as part of a thermal control assembly that sits under the TCW Compl. Ex. I, p. 20	¶78	col. 2:39-41
a thermal controller for selectively heating and maintaining temperatures of said areas of said wafer by controlling cooling of said cold plate and by controlling selective heating of said wafer TI layer	AEM's '885 patent allegedly discloses a "thermal controller 180" that controls the coldplate and the TCW to maintain temperatures of the wafer, including by adjusting power to heaters and adjusting coolant flow Compl. Ex. I, pp. 25-26	¶78	col. 2:41-44
a pin lift mechanism for displacing pins for lifting said wafer away from said wafer TI layer and wherein said cold plate and said wafer TI layer both comprise vertical alignment holes...to lift said wafer	AEM's '885 patent allegedly discloses "lifter pins" that extend through holes in both the coldplate and the TCW to lift the wafer away from the surface after testing Compl. Ex. I, p. 31 The complaint points to a screenshot of a "Cryogenic Wafer Prober" video as further evidence Compl. Ex. I, p. 15	¶78	col. 3:5-12

'841 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a wafer thermal interposer (TI) layer...wherein said wafer TI layer comprises a plurality of resistive traces traversing said wafer TI layer and wherein said plurality of resistive traces are operable to selectively heat a plurality of zones of said wafer TI layer	The complaint cites AEM's '885 "Copycat Patent," which allegedly discloses that the TCW comprises heaters, and "a heater may comprise a resistive trace that may emit thermal energy" Compl. Ex. J, p. 10 It also cites AEM's annual reports describing its technology as providing "unique multi-zone thermal control capabilities" Compl. Ex. J, p. 13 A screenshot from an AEM video shows active alignment of a probe Compl. Ex. J, p. 9	¶94	col. 4:2-8
a thermal controller for selectively heating and maintaining temperatures of said areas of said wafer...by controlling selective heating of said plurality of resistive traces of said wafer TI layer	AEM's '885 patent allegedly discloses a "thermal controller 180" that can control the temperature of a thermal zone by "adjusting power to the heaters in the heater zone" Compl. Ex. J, p. 20 AEM's public statements are also cited, touting "intelligent multi-zone control" Compl. Ex. J, p. 14	¶94	col. 4:10-14

• Identified Points of Contention:
  • Technical Questions: The infringement allegations rely heavily on disclosures in Defendants' own patents and marketing materials (the "Copycat Patents" and "PiXL" technology). A central evidentiary question will be whether the Accused Products, as manufactured and sold, actually implement the specific mechanisms described in those documents and required by the asserted claims, such as the "pin lift mechanism" of '999 claim 1.
  • Scope Questions: The complaint alleges that Defendants' "TCW" is the claimed "wafer thermal interposer." The case may raise the question of whether there are any material differences in the structure or operation of the TCW that would place it outside the scope of the claims, notwithstanding the allegations of copying.

V. Key Claim Terms for Construction

• The Term: "wafer thermal interposer (TI) layer"

• Context and Importance: This term is central to the claimed invention. Its scope will determine what structures can be considered an infringing heating layer. The dispute may center on whether Defendants' "Thermal Control Wafer" (TCW) falls within the proper construction of this term.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification functionally describes the TI layer as being "operable to contact a second surface of the wafer and operable to selectively heat areas of the wafer" '999 Patent, col. 2:36-39 This broad functional language could support an interpretation that covers any structure performing this role.
  • Evidence for a Narrower Interpretation: The specification also provides specific examples, such as an interposer comprising a base layer of aluminum nitride (AlN) with tungsten traces, manufactured using a high temperature co-fired ceramic (HTCC) process '999 Patent, col. 8:10-14 A defendant may argue that the term should be limited to these or similar disclosed embodiments.

• The Term: "thermal controller"

• Context and Importance: This term defines the "brains" of the system. Its construction is important for determining whether the control system in the Accused Products performs the specific coordinating functions required by the claims.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification discloses that the controller can be a general-purpose computer system, showing a block diagram of a computer with a processor and memory that can execute instructions to perform the claimed methodologies '999 Patent, FIG. 8 '999 Patent, col. 16:1-8 This may support a broad interpretation covering a wide range of hardware and software combinations.
  • Evidence for a Narrower Interpretation: Figure 1 of the patents depicts the "Thermal Controller" as a discrete block element (180) connected to the power supply and other components '999 Patent, FIG. 1 This could be used to argue for a narrower construction requiring a more specific or dedicated hardware component, rather than just a general-purpose computer.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Defendants instruct and encourage customers (e.g., Intel) to use the Accused Products in an infringing manner through datasheets, training manuals, and in-person support Compl. ¶82 It also alleges contributory infringement, asserting that Defendants' TCWs are a material component of the claimed system, are not a staple article of commerce, and have no substantial non-infringing use Compl. ¶83 Compl. ¶99
• Willful Infringement: The complaint alleges willful infringement based on Defendants' knowledge of the Asserted Patents. The bases for this knowledge include: (1) the fact that AEM's CEO, Samer Kabbani, is a named inventor on both Asserted Patents from his time at Advantest Compl. ¶80 Compl. ¶96; (2) Defendants' alleged citation to the Asserted Patents during the prosecution of their own "Copycat Patents" Compl. ¶80 Compl. ¶96; and (3) notice via the initial complaint filed on October 1, 2025 Compl. ¶85 Compl. ¶101

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

1. Evidentiary Linkage and Copying: A central issue, amplified by the willfulness allegations, will be one of technical origin: to what extent can Plaintiff prove that the accused "PiXL" and "TCW" technology is a direct derivative of the "wafer ATI" technology developed at Advantest? The alleged roles of key individuals and the history of prior arbitration will be a significant focus.
2. Claim Scope and Technical Equivalence: A key legal question will be one of definitional mapping: can the term "wafer thermal interposer," as defined in the context of the Asserted Patents, be construed to read on Defendants' "Thermal Control Wafer" products? The case may turn on whether any subtle structural or operational differences in Defendants' products are sufficient to escape the literal scope of the claims.
3. Willfulness and Exceptionality: A crucial question for damages will be one of intent: given the strong allegations of pre-suit knowledge, including the shared inventor and prosecution history citations, can Defendants establish a good-faith belief of non-infringement or invalidity? The outcome will determine the potential for enhanced damages and a finding that the case is exceptional.