Patent Description:
Quantum computation is based on the reliable control of quantum bits (referred to herein throughout as qubits). The fundamental operations required to realize quantum algorithms are a set of single-qubit operations and two-qubit operations which establish correlations between two separate quantum bits. The realization of high fidelity two-qubit operations may be desirable both for reaching the error threshold for quantum computation and for reaching reliable quantum simulations.

The superconducting quantum processor (having one or more superconducting qubits) includes superconducting metals (e.g., Al, Nb, etc.) on an insulating substrate (e.g., Si or high resistivity Si, Al<NUM>O<NUM>, etc.). The superconducting quantum processor is typically a planar two-dimensional lattice structure of individual qubits linked by a coupler in various lattice symmetry (for example, square, hexagonal, etc.), and a readout structure located on a flip-chip. The couplers can be made of a capacitor, a resonator, a coil or any microwave component that provides a coupling between qubits.

The flip-chip method may be needed for a relatively large number of qubits in a given qubit chip area. A qubit chip with a relatively large size (for example, a size greater than <NUM> by <NUM>) provides benefits in coherence when compared to connection of multi-chips with a relatively smaller size. The implementation of a relatively large number of qubits would require a qubit chip with a relatively larger size (for example, greater than <NUM> by <NUM>). However, a relatively larger (for example, a size greater than <NUM> by <NUM>) would need vias to break the box mode. Conventionally, forming vias in a qubit chip substrate requires thinning the substrate (e.g., a silicon substrate). The thinning of the substrate and the presence of vias can render the substrate weak and fragile. In conventional packaging methods, in order to alleviate the above problem, a plain support structure or a plain substrate handler (e.g., made of glass, silicon, etc.) is used to strengthen the substrate during manufacture. However, these conventional packaging methods require that the plain substrate handler be removed (i.e., de-bonded) in the final structure. However, removing the substrate handler in the final may create problems in the final structure including damaging the final structure such as damaging the substrate having the qubits, the qubits themselves and/or the interposer and/or other components during the removal procedure.

From prior art document <CIT> interconnect and semiconductor structures for assembly of cryogenic electronic packages are known.

Document <CIT> discloses a quantum bit device.

Document <CIT> discloses reducing loss in stacked quantum devices.

Document <CIT> discloses heat transfer for superconducting integrated circuits at millikelvin temperatures.

Document <CIT> discloses a cryogenic integrated circuit having a heat sink coupled to separate ground planes through differently sized thermal vias.

The present invention provides a quantum device as recited in claim <NUM>. The quantum device includes a qubit chip comprising a plurality of qubits and an interposer attached to and electrically connected to the qubit chip. The quantum device further includes a substrate handler attached to one side of the qubit chip or to one side of the interposer, or both so as to be thermally in contact with the qubit chip or the interposer, or both. The substrate handler includes a plurality of vias. At least a portion of plurality of vias are filled with a non-superconducting material, the non-superconducting material being selected to dissipate heat generated in the qubit chip, the interposer or both.

In an embodiment, the interposer is attached to and electrically connected to the qubit chip using solder bumps. In an embodiment, the quantum device further includes a bonding material. The substrate handler is attached to the one side of the qubit chip or to the one side of the interposer, or both using the bonding material. In an embodiment, the bonding material is an adhesive bonding material or a metal or an oxide bonding. In an embodiment, the bonding material can be polyimide, benzocyclobutene (BCB), acrylic, Al-Al bonding, In-In bonding, Sn-Sn boding, Au-Sn bonding, Au-In bonding, and Sn-In bonding, or any combination thereof.

In an embodiment, the quantum device further includes a plurality of thermally conductive studs configured and arranged to thermally connect the substrate handler to the one side of the qubit chip or to the one side of the interposer, or both.

In an embodiment, the quantum device further includes a superconducting material. The qubit chip and the interposer comprise a plurality of vias, at least a portion of the vias being filled with the superconducting material. In an embodiment, a back side of the qubit chip opposite to a side having the plurality of qubits has a layer of the superconducting material and a back side of the interposer opposite to a side of the interposer attached to and electrically connected to the qubit chip has a layer of the superconducting material.

In an embodiment, the substrate handler has a plurality of vias, a portion of the plurality of vias being filled with superconducting material and at least one of the plurality of vias being substantially empty to operate as at least one window-via. In an embodiment, the at least one window-via is located on a back side of a location of a qubit of the plurality of qubits so as to enable a laser beam to be transmitted through the at least one window-via to controllably remove a metal layer connected to the qubit and change a capacitance of the qubit. In an embodiment, the interposer and the substrate handler comprise at least one window-via that traverses both the interposer and the substrate handler so as to enable a laser beam to be transmitted therethrough to a frontside of the qubit to modify the qubit. In an embodiment, the interposer and the substrate handler include at least one window-via that traverses both the interposer and the substrate handler so as to enable a plasma to be transmitted therethrough to the qubit chip.

In an embodiment, the interposer includes a plurality of vias, a first portion of the plurality of vias is filled with superconducting material for ground connection and a second portion of the plurality of vias is filled with superconducting material for signal transmission.

In an embodiment, the quantum device also includes a first heat sink thermally and mechanically in contact with the substrate handler, the heat sink being configured to further dissipate heat dissipated by the substrate handler. In an embodiment, the quantum device further includes an organic substrate attached to and electrically connected to the interposer using a plurality of solder bumps. In an embodiment, the first heat sink is further attached to the organic substrate.

The present invention further provides a method of making a quantum device as recited in claim <NUM>. The method includes providing a first substrate handler; providing a qubit chip substrate; forming a plurality of vias through the first substrate handler; filling the plurality of vias with non-superconducting thermally conducting material; forming a plurality of thermally conductive studs on one side of the first substrate handler; forming a plurality of vias in a first face of the qubit chip substrate; filling the plurality of vias with a superconducting material; and bonding the first face of the qubit chip substrate to the one side of the first substrate handler having the thermally conductive studs.

In an embodiment, the method further includes grinding a second face of the qubit chip substrate, the second face being opposite to the first face until reaching the plurality of vias in the first face of the qubit chip substrate; forming capacitors and bus lines on the ground second face using a superconducting material; and forming a plurality of qubits on the ground second face of the qubit chip substrate and connecting the plurality of qubits to the capacitors and bus lines to obtain a qubit chip support structure.

In an embodiment, bonding the first face of the qubit chip substrate to the one side of the substrate handler having the thermally conductive studs includes bonding using a polymer material, a metal bonding, or an oxide bonding.

In an embodiment, the method also includes providing a second substrate handler; providing an interposer substrate; forming a plurality of via through the second substrate handler; filling the plurality of via with non-superconducting thermally conducting material; forming a plurality of thermally conductive studs on one side of the second substrate handler; forming a plurality of via in a first face of the interposer substrate; filling the plurality of via with a superconducting material; and bonding the first face of the interposer substrate to the one side of the second substrate handler having the thermally conductive studs.

In an embodiment, the method further includes grinding a second face of the interposer substrate, the second face being opposite to the first face until reaching the plurality of via in the first face of the interposer substrate; forming readout resonators, capacitive coupled lines, and drive lines using a superconducting material; and applying solder bumps on the ground second face of the interposer substrate to obtain an interposer support structure.

In an embodiment, the method includes contacting a side of the qubit chip support structure having the qubits with a side of the interposer support structure having the solder bumps. In an embodiment, prior to contacting the side of the qubit chip support structure having the plurality of qubits with the side of the interposer support structure having the solder bumps, dicing the qubit support structure having the plurality of qubits into a plurality of qubit chips. In an embodiment, the method further includes contacting each of the plurality of qubit chips having the qubits with the side of the interposer support structure having the solder bumps. In an embodiment, the method further includes bonding the interposer support structure to an organic substrate.

The present method and quantum device have many benefits including a relative ease of implementation as well as eliminating unnecessary conventional steps such as removing substrate handler (i.e., de-bonding the substrate handler) in the final structure. In fact, to the contrary, the substrate handler of the present invention remains in the final structure and can provide additional rigidity to the structure while acting as a heat dissipator.

The present disclosure, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures.

<FIG> is a schematic cross-section view of a quantum mechanical device <NUM>, according to an embodiment of the present invention. The quantum mechanical device <NUM> includes a qubit chip <NUM> including a plurality of qubits <NUM>. In an embodiment, the plurality of qubits can be, for example, superconducting qubits such as transmon qubits, xmon qubits, fluxonium qubits, etc. The term "qubit chip" is used herein broadly to mean a substrate including two or more qubits.

The quantum mechanical device <NUM> also includes an interposer <NUM> attached to and electrically connected to the qubit chip <NUM>. In an embodiment, the interposer <NUM> is attached to and electrically connected to the qubit chip <NUM> using solder bumps <NUM>.

In an embodiment, the quantum mechanical device <NUM> also includes superconducting material <NUM>. In an embodiment, the qubit chip <NUM> has a plurality of vias 102A and the interposer has a plurality of vias 106A. In an embodiment, at least a portion of vias 102A and/or 106A are filled with the superconducting material <NUM>. In an embodiment, the interposer <NUM> has a first portion of the plurality of vias 106A filled with superconducting material <NUM> for ground connection and a second portion of the plurality of vias 106A filled with superconducting material <NUM> for signal transmission. In an embodiment, the vias 102A of the qubit chip <NUM> can have a size ranging from <NUM> to <NUM> in diameter for the circle type and ring width of <NUM> to <NUM> for the annular type. In an embodiment, the vias 106A of the interposer <NUM> can also have a size ranging from <NUM> to <NUM> in diameter for the circle type and ring width of <NUM> to <NUM> for the annular type.

In an embodiment, a back side 102B of the qubit chip <NUM> opposite to a front side 102C of the qubit chip <NUM> having the plurality of qubits <NUM> has a layer 110B of the superconducting material <NUM>. In an embodiment, a back side 106B of the interposer <NUM> opposite to a front side 106C of the interposer <NUM> attached to and electrically connected to the qubit chip <NUM> has a layer 110A of the superconducting material <NUM>.

The quantum mechanical device <NUM> also includes a substrate handler 112A, 112B attached to one side of the qubit chip <NUM> or attached to one side of the interposer <NUM>, or both. For example, in an embodiment, the substrate handler 112A can be attached to and thermally in contact with the back side 102B of the qubit chip <NUM> and the substrate handler 112B can be attached to and thermally in contact with the back side 106B of the interposer <NUM>. In an embodiment, the substrate handler 112B can be made of glass, silicon, etc..

In an embodiment, the substrate handler 112A includes a plurality of vias 114A and the substrate handler 112B includes a plurality of vias 114B. In an embodiment, at least a portion of the plurality of vias 114A and/or 114B are filled with a non-superconducting material <NUM>. The non-superconducting material <NUM> can be selected to dissipate heat generated in the qubit chip <NUM>, the interposer <NUM> or both. In an embodiment, the vias 114A, 114B in the substrate handlers 112A, 112B, respectively, have a size ranging from <NUM> to <NUM> in diameter for the circle type and ring width of <NUM> to <NUM> for the annular type. In an embodiment, the vias 114A, 114B of the substrate handlers 112A, 112B, respectively, have larger size (e.g., about ten times larger) than the vias 102A of the qubit chip <NUM> or the vias 106A of the interposer <NUM>.

In an embodiment, the quantum mechanical device <NUM> further includes a bonding material <NUM>. The substrate handler 112A, 112B is attached to the back side 102B of the qubit chip <NUM> or to the back side 106B of the interposer <NUM>, or both using the bonding material <NUM>. For example, the substrate handler 112A is attached to the back side 102B of the qubit chip <NUM> using the bonding material <NUM> and the substrate handler 112B is attached to the back side 106B of the interposer <NUM> using the bonding material <NUM>. In an embodiment, the bonding material <NUM> is an adhesive bonding material or a metal or an oxide bonding. In an embodiment, the bonding material <NUM> can be any of polyimide, benzocyclobutene (BCB), acrylic, Al-Al bonding, In-In bonding, Sn-Sn boding, Au-Sn bonding, Au-In bonding, and Sn-In bonding, or any combination of two or more thereof.

In an embodiment, the quantum mechanical device <NUM> further includes a plurality of thermally conductive studs 120A, 120B configured and arranged to thermally connect the substrate handler 112A, 112B to the back side 102B of the qubit chip <NUM> or to the back side 106B of the interposer <NUM>, or both. For example, thermally conductive studs 120A are configured and arranged to thermally connect the substrate handler 112A to the back side 102B of the qubit chip <NUM>, and thermally conductive studs 120B are configured and arranged to thermally connect the substrate handler 112B to the back side 106B of the interposer <NUM>. In an embodiment, the thermally conductive studs 120A, 120B can be any thermally conductive material including, but not limited to, Cu, Au, electroplated Cu, electroplated Au, electroplated Re or any combination thereof, and/or solder materials such as Sn, In, etc..

<FIG> is a schematic enlarged cross-section view of the quantum mechanical device <NUM>, according to an embodiment of the present invention. In <FIG>, same reference numerals indicate same components described above with respect to <FIG>. Therefore, description of common components will not be repeated in the following paragraphs and only specific features are highlighted. For example, in an embodiment, in addition to substrate handler(s) 112A, 112B, qubit chip <NUM>, interposer <NUM>, bonding material <NUM> and studs 102A, 120B, the quantum mechanical device <NUM> further includes a heat spreader material <NUM>. For example, the heat spreader material <NUM> can be provided between the back side 102B of the qubit chip <NUM> and the bonding material <NUM> in contact with the thermally conductive studs 120A. For example, the heat spreader <NUM> can also be provided between the back side 106B of the interposer <NUM> and the bonding material <NUM> in contact with the thermally conductive studs 120B. In this way, the heat spreader <NUM> is configured to transfer heat from the qubit chip <NUM>, the interposer <NUM>, or both to the substrate handler 112A or the substrate handler 112B, or both.

For example, heat from the qubit chip <NUM> can be spread out along the back side 102B of the qubit chip <NUM> by the heat spreader <NUM> and then transmitted through thermally conductive studs 120A to the plurality of vias 114A in the substrate handler 112A which are filled with non-superconducting heat dissipating material <NUM>. Similarly, heat from the interposer <NUM> can be spread out along the back side 106B of the interposer <NUM> by the heat spreader <NUM> and then transmitted through thermally conductive studs 120B to the plurality of vias 114B in the substrate handler 112B which are filled with non-superconducting heat dissipating material <NUM>.

<FIG> is a schematic cross-section view of the quantum mechanical device <NUM>, according to an embodiment of the present invention. Similarly, same reference numerals indicate same components described above with respect to <FIG> and <FIG>. Therefore, description of common components will not be repeated in the following paragraphs and only specific features are highlighted. In an embodiment, the quantum mechanical device <NUM> further includes a heat sink 302A thermally and mechanically in contact with the substrate handler 112A which is thermally in contact with the qubit chip <NUM>. The heat sink 302A is configured to further dissipate heat dissipated by the substrate handler 112A. In an embodiment, the quantum mechanical device <NUM> further includes a heat sink 302B thermally and mechanically in contact with the substrate handler 112B which is thermally in contact with the interposer <NUM>. The heat sink 302B is configured to further dissipate heat dissipated by the substrate handler 112B.

In an embodiment, the quantum mechanical device <NUM> further includes an organic substrate <NUM> attached to and electrically connected to the interposer <NUM>. In an embodiment, the organic substrate <NUM> is attached and electrically connected to the interposer <NUM> using a plurality of solder bumps <NUM>. In an embodiment, as shown in <FIG>, the organic substrate <NUM> is attached and electrically connected to the front side 106C of the interposer <NUM> that is attached to and electrically connected to the qubit chip <NUM>. In an embodiment, the organic substrate <NUM> can be, for example, a laminate.

In an embodiment, the heat sink 302A is further attached to the organic substrate <NUM> using a plurality of fasteners <NUM>. The fasteners <NUM> are used to fasten the heat sink 302A, the organic substrate <NUM> and the heat sink 302B together to form a rigid and sturdy structure. In an embodiment, electromagnetic signal lines, connectors, etc. (e.g., ardent connectors) <NUM> for carrying electromagnetic signals (e.g., microwave signals) are connected to the organic substrate <NUM> which is configured to transmit the electromagnetic signals through the solder bumps <NUM> to the interposer <NUM>.

<FIG> is a schematic cross-section view of a quantum mechanical device <NUM>, according to another embodiment of the present invention. The quantum mechanical device <NUM> is similar in many aspects with the quantum mechanical device <NUM>. Therefore, common components are referred to herein using the same reference numerals. Similar to quantum mechanical device <NUM>, the quantum mechanical device <NUM> includes the qubit chip <NUM>, the interposer <NUM> and substrate handlers 112A and 112B, etc. In the quantum mechanical device <NUM>, the organic substrate <NUM> is attached to and electrically connected to the front side 106C of the interposer <NUM>. However, in the quantum mechanical device <NUM>, the organic substrate <NUM> is instead attached and electrically connected to the back side 106B of the interposer <NUM>. In an embodiment, the organic substrate <NUM> is attached and electrically connected to the back side 106B of the interposer <NUM> using solder bumps <NUM>. In an embodiment, electromagnetic signal lines, connectors, etc. (e.g., ardent connectors) <NUM> for carrying electromagnetic signals (e.g., microwave signals) are connected to the organic substrate <NUM> which is configured to transmit the electromagnetic signals through the solder bumps <NUM> to the interposer <NUM>.

<FIG> is a schematic cross-section view of a quantum mechanical device <NUM>, according to an embodiment of the present invention. The quantum mechanical device <NUM> is similar in many aspects with the quantum mechanical device <NUM> as shown in <FIG>, for example. Therefore, common components are referred to herein using the same reference numerals. Similar to quantum mechanical device <NUM>, the quantum mechanical device <NUM> includes the qubit chip <NUM>, the interposer <NUM> and substrate handlers 112A and 112B, etc..

As described previously with reference to the quantum mechanical device <NUM>, the substrate handler 112A attached to the qubit chip <NUM> includes a plurality of vias 114A and the substrate handler 112B attached to the interposer <NUM> includes a plurality of vias 114B. At least a portion of plurality of vias 114A and/or 114B are filled with a non-superconducting material <NUM>. The non-superconducting heat dissipating material <NUM> can be selected to dissipate heat generated in the qubit chip <NUM>, the interposer <NUM>, or both. As shown in <FIG>, instead of filling some of the vias 114A, 114B with the non-superconducting material <NUM>, some of the vias 114A, 114B are not filled with non-superconducting heat dissipating material <NUM>. In an embodiment, at least one window-via <NUM> is provided in addition to the vias 114A, 114B that are filled with the non-superconducting material <NUM>.

<FIG> is a schematic top view of the quantum mechanical device <NUM>, according to an embodiment of the present invention. <FIG> shows that some of the vias 114A, 114B are filled with non-superconducting heat dissipating material <NUM> while some of the vias are left empty and instead at least one window-via <NUM> is provided therein. The at least window-via <NUM> is located on a back side 102B, 106B of the qubit chip <NUM> and interposer <NUM>, respectively, at a location of a qubit 104A in the plurality of qubits <NUM>. As shown in <FIG>, the at least one window-via <NUM> traverses a full depth of the substrate handler 112A, 112B as well as the bonding material <NUM> and the non-superconducting heat spreader <NUM>. This can enable a laser beam to be transmitted through the at least one window-via <NUM> to controllably remove a metal layer connected to the qubit 104A and change a capacitance of the qubit 104A.

<FIG> is a schematic cross-section view of the quantum mechanical device <NUM>, according to an embodiment of the present invention. As shown in <FIG>, the quantum mechanical device <NUM> has a plurality of window-vias <NUM>. For example, a laser beam <NUM> can be transmitted through one of the window-vias <NUM> to reach the back side 102B of the qubit chip <NUM> to remove metal from metal layer or superconducting material <NUM> at or near a qubit pocket 104B where the qubit 104A is mounted. By removing metal at or near the qubit pocket 104B, a capacitance can be changed and thus the frequency of the qubit 104B can be modified as desired.

<FIG> is a schematic cross-section view of a quantum mechanical device <NUM>, according to an embodiment of the present invention. As shown in <FIG>, the quantum mechanical device <NUM> is similar in many aspects to the quantum mechanical devices <NUM>, <NUM>, <NUM> described in the above paragraphs. Therefore, same reference numerals are used in <FIG> to refer to same components. As shown in <FIG>, in addition to the at least window-via <NUM> provided within the interposer <NUM> and the substrate handler 112B attached to the backside 106B of the interposer <NUM>, at least plasma window-via <NUM> is also provided within the interposer <NUM> and the substrate handler 112B. However, as illustrated in <FIG>, the laser beam <NUM> is used to remove metal or superconducting material from the front side 102C of the qubit chip <NUM> where the qubit 104A is mounted. In addition, the at least plasma window-via <NUM> traverses both the interposer <NUM> and the substrate handler 112B. This enable a plasma to be transmitted through the plasma window-via <NUM> to qubit chip <NUM> to, for example, modify or improve coherence.

<FIG> show various steps of a method of making the quantum mechanical devices <NUM>, <NUM>, <NUM>, <NUM> described in the above paragraphs, according to an embodiment of the present invention. The method includes providing a first substrate handler <NUM> and providing a qubit chip substrate <NUM>, as shown in <FIG>, respectively. The method further includes forming a plurality of vias <NUM> through the first substrate handler <NUM>, as shown in <FIG>, and filling the plurality of vias <NUM> with non-superconducting thermally conducting material <NUM>, as shown in <FIG>. The method also includes forming a plurality of thermally conductive studs <NUM> on one side <NUM> of the first substrate handler <NUM>, as shown in <FIG>.

The method further includes forming a plurality of vias <NUM> in a first face <NUM> of the qubit chip substrate <NUM>, as shown in <FIG>. The method also includes filling the plurality of vias <NUM> with a superconducting material <NUM>, as shown in <FIG>. After filling the plurality of vias <NUM> with the superconducting material <NUM>, the method includes bonding the first face <NUM> of the qubit chip substrate <NUM> to the one side <NUM> of the first substrate handler <NUM> having the thermally conductive studs <NUM>, as shown in <FIG>.

In an embodiment, bonding the first face <NUM> of the qubit chip substrate <NUM> to the one side <NUM> of the substrate handler <NUM> having the thermally conductive studs <NUM> includes bonding using a polymer material, a metal bonding, or an oxide bonding <NUM>, as shown in <FIG>.

<FIG> show additional steps of the method of making the quantum mechanical devices <NUM>, <NUM>, <NUM>, <NUM> described in the above paragraphs, according to an embodiment of the present invention. The method further includes grinding a second face <NUM> of the qubit chip substrate <NUM>, the second face <NUM> being opposite to the first face <NUM> until reaching the plurality of vias <NUM> in the first face <NUM> of the qubit chip substrate <NUM>, as shown in <FIG>. The method further also includes forming capacitors and bus lines on the ground second face <NUM> using a superconducting material, as shown in <FIG>. The method includes forming a plurality of qubits <NUM> on the ground second face <NUM> of the qubit chip substrate <NUM> and connecting the plurality of qubits <NUM> to the capacitors and bus lines to obtain a qubit chip support structure <NUM>, as shown in <FIG>.

The method includes providing a second substrate handler <NUM> and providing an interposer substrate <NUM>, as shown in <FIG>. In an embodiment, the method includes similar steps to the steps described above with reference to <FIG> and <FIG> which are performed on second substrate handler <NUM> and interposer substrate <NUM>. For example, the method includes forming a plurality of vias <NUM> through the second substrate handler <NUM> and filling the plurality of vias <NUM> with non-superconducting thermally conducting material <NUM>, as shown in <FIG>. The method also includes forming a plurality of thermally conductive studs <NUM> on one side <NUM> of the second substrate handler <NUM>, as shown in <FIG>. The method includes forming a plurality of vias <NUM> in a first face <NUM> of the interposer substrate <NUM>, as shown in <FIG>. The method further includes filling the plurality of vias <NUM> with a superconducting material <NUM>. The method also includes bonding the first face <NUM> of the interposer substrate <NUM> to the one side <NUM> of the second substrate handler <NUM> having the thermally conductive studs <NUM>. In an embodiment, bonding the first face <NUM> of the interposer substrate <NUM> to the one side <NUM> of the second substrate handler <NUM> includes bonding using a polymer material, a metal bonding, or an oxide bonding <NUM>, as shown in <FIG>.

The method further includes grinding a second face <NUM> of the interposer substrate <NUM>, the second face <NUM> being opposite to the first face <NUM> until reaching the plurality of vias <NUM> in the first face <NUM> of the interposer substrate <NUM>, as shown in <FIG>. The method also includes forming readout resonators, capacitive coupled lines, and drive lines using a superconducting material on the ground second face <NUM> of the interposer substrate <NUM>.

The method includes applying solder bumps <NUM> on the ground second face <NUM> of the interposer substrate <NUM> to obtain an interposer support structure <NUM>, as shown in <FIG>. In an embodiment, the method includes contacting a side <NUM> of the qubit chip support structure <NUM> having the qubits <NUM> with a side <NUM> of the interposer support structure <NUM> having the solder bumps <NUM>, as shown in <FIG>.

In an embodiment, prior to contacting the side <NUM> of the qubit chip support structure <NUM> having the plurality of qubits <NUM> with the side <NUM> of the interposer support structure <NUM> having the solder bumps <NUM>, dicing the qubit support structure <NUM> having the plurality of qubits <NUM> into a plurality of qubit chips <NUM>, as shown in <FIG>. In an embodiment, the method further includes contacting each of the plurality of qubit chips <NUM> having the qubits <NUM> with the side <NUM> of the interposer support structure <NUM> having the solder bumps <NUM>, as shown in <FIG>. In an embodiment, the method also includes bonding the interposer support structure <NUM> to an organic substrate <NUM>.

Claim 1:
A quantum device (<NUM>), comprising:
a qubit chip (<NUM>) comprising a plurality of qubits (<NUM>);
an interposer (<NUM>) attached to and electrically connected to the qubit chip (<NUM>);
a substrate handler (112A, <NUM> B) attached to one side of the qubit chip (<NUM>) or to one side of the interposer (<NUM>), or both so as to be thermally in contact with the qubit chip (<NUM>) or the interposer (<NUM>), or both,
wherein the substrate handler (112A, <NUM> B) includes a plurality of vias (114A, 114B), characterized in that at least a portion of plurality of vias (114A, 114B) being filled with a non-superconducting material (<NUM>), the non-superconducting material (<NUM>) being selected to dissipate heat generated in the qubit chip (<NUM>), the interposer (<NUM>) or both.