A semiconductor structure and methods of forming the semiconductor structure generally includes providing a thermocompression bonded superconducting metal layer sandwiched between a first silicon substrate and a second silicon substrate. The second substrate includes a plurality of through silicon vias to the thermocompression bonded superconducting metal layer. A second superconducting metal is electroplated into the through silicon vias using the thermocompression bonded superconducting metal layer as a bottom electrode during the electroplating process, wherein the filling is from the bottom upwards.

A method is provided of forming a superconductor interconnect structure. The method comprises forming a dielectric layer overlying a substrate, forming an interconnect opening in the dielectric layer, and moving the substrate to a deposition chamber. The method further comprises performing a cleaning process on the top surface of the dielectric layer and in the interconnect opening while in the deposition chamber, and depositing a superconducting metal in the interconnect opening while in the deposition chamber to form a superconducting element in the superconductor interconnect structure.

A cryogenic quantum bit package with multiple qubit circuits facilitates inter-qubit signal propagation using a multi-chip module (MCM). Multiple qubits are grouped within the package into one or more qubit integrated circuits (ICs). The qubit ICs themselves are electrically coupled to each other via a structure including a superconducting MCM and superconducting interconnects. Coupling of quantum electrical signals between a qubit and other qubits, a substrate, or the MCM uses a coupler circuit, such as a Josephson junction, capacitor, inductor, or resonator.

Fabricating wiring layers above a Josephson junction multi-layer may include removing a part of the multilayer; depositing an insulating layer to overlie a part of the multilayer; and patterning the insulating layer to define a hole in the insulating layer. The method includes depositing a first superconducting wiring layer over a part of the insulating layer and within a portion of the hole. Further, insulating and wiring layers may be deposited and a topmost wiring layer defined. The method includes depositing a passivating layer to overlie the topmost wiring layer. Fabricating a superconducting integrated circuit comprising a hybrid dielectric system may include depositing a high-quality dielectric layer that overlies a superconducting feature. The method includes depositing a second dielectric layer that overlies at least part of the high-quality dielectric layer. The second dielectric layer can comprise a conventional dielectric material.

A method of forming a superconducting structure is provided that includes forming a superconducting element in a first dielectric layer, forming a protective pad formed from a resistive material over at least a portion of the superconducting element, forming a second dielectric layer overlying the first dielectric layer, and etching an opening through the second dielectric layer to the protective pad, such that no portion of the superconducting element is exposed in the opening. A cleaning process is performed on the superconducting structure, and a contact material fill with a resistive material is performed to fill the opening and form a resistive element in contact with the superconducting element through the protective pad.

An integrated circuit is provided that comprises a first thermal sink layer, a first ground plane associated with a first set of circuits that have a first operational temperature requirement, a first thermally conductive via that couples the first ground plane to the first thermal sink layer, a second thermal sink layer, a second ground plane associated with a second set of circuits that have a second operational temperature requirement that is higher than the first operational temperature requirement, and a second thermally conductive via that couples the second ground plane to the second thermal sink layer. The first thermal sink layer is cooled at a first temperature to maintain the first set of circuits at the first operational temperature requirement and the second thermal sink layer is cooled at a second temperature to maintain the second set of circuits at the second operational temperature requirement.

The embodiments herein describe technologies of cryogenic digital systems with a first component located in a first cryogenic temperature domain and a second component located in a second cryogenic temperature domain that is lower in temperature than the first cryogenic temperature domain. An electrical conductor is coupled between the first component and the second component along a first plane. The electrical conductor carries a signal between the first component and the second component. A cooling assembly is coupled to a segment of the electrical conductor. The cooling assembly may include an electrical insulator including ceramic material. The cooling assembly may include a cold plate, two cold plates, or an orthogonal cold strip.

A method of forming a superconductor structure is provided. The method comprises forming a superconducting element in a first dielectric layer that has a top surface aligned with the top surface of the first dielectric layer, forming a second dielectric layer over the first dielectric layer and the superconducting element, and forming an opening in the second dielectric layer to a top surface of the superconducting element. The method also comprises performing a cleaning process on the top surface of the superconducting element to remove oxides formed on the top surface of the superconducting element at a first processing stage, forming a protective barrier over the top surface of the superconducting element, and moving the superconductor structure to a second processing stage for further processing.

Examples described in this disclosure relate to superconducting devices, including reciprocal quantum logic (RQL) compatible devices. A superconducting device including at least one superconducting element having a first coefficient of thermal expansion is provided. The at least one superconducting element is formed on a dielectric layer having a second coefficient of thermal expansion and the first coefficient of thermal expansion is different from the second coefficient of thermal expansion causing a strain mismatch between the at least one superconducting element and the dielectric layer when the superconducting device is operating in a cryogenic environment. The superconducting device may also include at least one dummy element configured to lower stress at an interface between the at least one superconducting element and the dielectric layer when the at least one superconducting device is operating in the cryogenic environment.

A method is provided of forming a superconductor device interconnect structure. The method includes forming a first dielectric layer overlying a substrate, and forming a superconducting interconnect element in a first dielectric layer, such that the superconducting interconnect element has a top surface aligned with a top surface of the first dielectric layer to form a first interconnect layer. The method also includes performing a plasma clean on a top surface of the first interconnect layer, and depositing a second dielectric layer over the first dielectric layer.