Delegated Director Review Panel Concludes Claims 1-8, 12, 13, and 17 of Infineon's '562 Patent Have Been Proven Unpatentable and Remands Other Grounds.

The proceeding

The proceeding is Innoscience America, Inc. v. Infineon Technologies Americas Corp., IPR2025-00175. Innoscience America, Inc. is the petitioner. Infineon Technologies Americas Corp. is the patent owner. The petition, Paper 1, requested inter partes review of claims 1-17 of U.S. Patent 8,686,562 B2. Paper 36, dated November 5, 2026, is the delegated rehearing panel's decision. Judge Finamore wrote it for a panel of Chief Administrative Patent Judge Kalyan K. Deshpande, Vice Chief Administrative Patent Judge Michael W. Kim, and Acting Vice Chief Administrative Patent Judge Alyssa A. Finamore.

Petitioner requested Director Review (Paper 31) of the final written decision (Paper 30). With the Director's authorization, patent owner filed a response (Paper 32). The USPTO's Director Review status spreadsheet lists petitioner's request as dated July 30, 2026, with a disposition of delegated on September 9, 2026. The Director delegated the review to this panel to determine whether the Board misapprehended or overlooked any issues, including the appropriate construction of "electrode stack" and whether Yu teaches, or Usui discloses, an "electrode stack" under that construction (Paper 33 at 3; Paper 34). A footnote states that a panel was identified in Paper 34 and that a new panel was later designated (Paper 35).

The patent

U.S. Patent 8,686,562 B2 is titled "Refractory Metal Nitride Capped Electrical Contact and Method for Frabricating Same," as printed on the patent. It issued April 1, 2014, from Application No. 12/583,809, filed August 25, 2009, and names Sadiki Jordan as inventor. The face of the patent names an earlier assignee. The inter partes review names Infineon Technologies Americas Corp. as patent owner.

Claim 1 is an electrical contact for use on a semiconductor device. It recites an electrode stack including a plurality of metal layers and a capping layer formed over that plurality of metal layers. The capping layer consists only of a refractory metal nitride. That refractory metal nitride forms a top of the electrical contact and has a thickness greater than that of a bottommost layer of the plurality of metal layers.

Claims 2 and 3 recite a capping layer that comprises titanium nitride (TiN) or tantalum nitride (TaN), respectively. Claim 4 recites first, second, and third metal layers, with the second metal layer formed between the first and the third and the capping layer formed on the third. Claims 5, 6, and 7 recite titanium (Ti) for the first and third metal layers, aluminum (Al) for the second metal layer, and silicon (Si) in the second metal layer. Claim 8 recites that the electrical contact is configured for implementation on a group III-V semiconductor device. Claims 9, 10, 11, and 12 recite a high electron mobility transistor (HEMT), a power electrode making ohmic contact, a gate electrode making Schottky contact, and a gate insulator layer underlying the first metal layer of the electrode stack to provide an insulated gate electrode.

Claim 13 is an electrical contact for use on a group III-V semiconductor device. It recites an electrode stack including a plurality of metal layers and a capping layer formed over that plurality of metal layers. The capping layer consists only of a metal selected from the group consisting of titanium nitride (TiN) and tantalum nitride (TaN). That metal forms a top of the electrical contact and has a thickness greater than that of a bottommost layer of the plurality of metal layers. Claims 14, 15, 16, and 17 recite a HEMT, a power electrode making ohmic contact, a gate electrode making Schottky contact, and a gate insulator layer underlying a first metal layer of the electrode stack to provide an insulated gate electrode.

The final written decision

In the final written decision, Paper 30, the Board found that petitioner had not shown, by a preponderance of the evidence, that any of claims 1-17 are unpatentable. The Board construed "electrode stack" as "a conductor that provides a path for current entering or leaving a medium such as a semiconductor device" (Paper 30 at 13). It declined to adopt patent owner's proffered construction (Paper 30 at 17).

On that construction, the Board determined that petitioner failed to show that Usui anticipates claims 1, 2, and 4-7, because petitioner did not show that Usui's "interconnect metallurgy structure" teaches an "electrode stack" (Paper 30 at 21-23). The Board also determined that petitioner failed to show that the combination of Yu and Usui renders obvious claims 1-8, 12, 13, and 17, because petitioner did not "provide an adequate explanation of why or how [Yu's] dielectric layers 214 and 216 are part of the 'electrode stack'" (Paper 30 at 30-31).

Construction and Usui

The panel determines that the Board's construction of "electrode stack" is the appropriate construction, for the reasons stated in the final written decision, which the panel adopts (Paper 30 at 10-18). It agrees that the Board adopted a simplified version of petitioner's proposed construction, and it is unpersuaded by petitioner's argument that the Board misconstrued the term. The panel finds that Usui and Yu each disclose an "electrode stack" under that construction.

On anticipation, petitioner identifies Usui's interconnect, including underlayer 13, metal layers 14, 15, and 18, and capping layer 19, as the recited electrode stack. The panel agrees that this interconnect is an electrode stack under the construction. It treats a description of those interconnects as conductors that carry very high current densities, and that form electrical connections between devices, as indistinguishable from the construction. Patent owner argues that carrying current between devices is not the same as a path for current entering or leaving the semiconductor, and points to Usui's stud 10, a layer between the interconnect and a semiconductor layer, as what makes contact with the semiconductor (Ex. 1004, Fig. 8). The panel disagrees with that reading of the construction. It agrees with petitioner that a path for current does not require direct contact between the electrode stack and the semiconductor, and that an indirect path via an intermediary, such as stud 10, is sufficient.

The panel states that it considered petitioner's assertions that Usui teaches the other limitations of claims 1, 2, and 4-7, agrees with petitioner, and is not persuaded by patent owner's arguments. It determines that petitioner has met its burden of showing that Usui anticipates claims 1, 2, and 4-7.

Yu with Usui, and the remand

On obviousness, petitioner identifies Yu's metal gate stacks 230 and 231, including metal layers 218, 220, 222, and 224 and capping layer 226, as the electrode stack recited in claims 1 and 13. Patent owner argues that those gate stacks also include insulating dielectric layers 214 and 216. The panel agrees with petitioner that the construction does not preclude an insulator under the metal layers of the electrode stack, as Yu discloses (Ex. 1005, Fig. 2E). It points to dependent claims 12 and 17. Claim 12 recites a gate insulator layer underlying the first metal layer of the electrode stack, and claim 17 recites a gate insulator layer underlying a first metal layer of the electrode stack, in each case to provide an insulated gate electrode. The decision describes each claim as reciting an insulator layer underlying the electrode stack.

The panel also finds that Yu discloses the recited capping layer: a refractory metal nitride capping layer in claim 1, and, in independent claim 13, a titanium nitride (TiN) or tantalum nitride (TaN) capping layer. It is persuaded by petitioner's explanation that Yu's bottommost layer is 20 angstroms thick, that capping layer 226 may include metal, such as titanium nitride, and that the metal capping layer 226 is thicker than the bottommost layer for the entire range of 50 to 1,000 angstroms. The panel concludes that petitioner has met its burden of showing that Yu and Usui render obvious claims 1-8, 12, 13, and 17.

For Grounds 2-4, 6, and 7, the final written decision relied on the deficiencies it found in the Usui ground and the Yu and Usui ground, and it did not address those other grounds substantively (Paper 30 at 24-25 and 32). Because the panel determines that petitioner met its burden on the Usui ground and the Yu and Usui ground, it remands for the Board to consider Grounds 2-4, 6, and 7 in light of this decision. It leaves the conduct of the remand, including whether any additional briefing is warranted, to the Board.

The order

The order modifies the final written decision to conclude that claims 1-8, 12, 13, and 17 have been proven unpatentable. It further remands the case for consideration of the patentability of the claims challenged in Grounds 2-4, 6, and 7. Claims 9, 10, 11, 14, 15, and 16 are not in that modified unpatentability conclusion.

The '562 patent in court and at the ITC

According to the parties' joint stipulation in Infineon Technologies Austria AG v. Innoscience (Suzhou) Technology Company, Ltd., No. 4:24-cv-01553-YGR (N.D. Cal.), Infineon Technologies Austria AG and Infineon Technologies Americas Corp. filed an amended complaint on July 23, 2024 asserting the '562 patent, together with U.S. Patents 9,899,481, 9,070,755, and 8,264,003, against Innoscience (Suzhou) Technology Company, Ltd., Innoscience (Zhuhai) Technology Company, Ltd., and Innoscience America, Inc. (ECF No. 55). On August 30, 2024, the court granted that stipulation, which sought a stay pending final resolution of the ITC investigation, and stayed the case (ECF No. 56).

The ITC proceeding is Investigation No. 337-TA-1414, Certain Semiconductor Devices and Products Containing the Same, on a complaint filed July 26, 2024 by Infineon Technologies Americas Corp. of El Segundo, California and Infineon Technologies Austria AG of Villach, Austria. The notice of institution covers claims 1, 2, 8-10, and 13-15 of the '562 patent, along with claims of the other three patents, and names four Innoscience respondents, including Innoscience America, Inc. (89 Fed. Reg. 70667 (Aug. 30, 2024)). A later Commission notice states that on May 20, 2025, the Commission determined not to review an initial determination (Order No. 46) granting complainants' unopposed motion to terminate the investigation as to all asserted claims of the '562 patent (91 Fed. Reg. 5259, 5260 (Feb. 5, 2026)).

What to watch next

Watch for the Board's order on remand addressing Grounds 2-4, 6, and 7, including any direction on further briefing. The proceeding can end at any time, including by settlement.