Quantum device having quantum chip on interposer in contact with sample stage
A quantum device capable of improving a cooling effect while securing the number of terminals is provided. A quantum device according to an example embodiment includes a quantum chip 10 , and an interposer 20 on which the quantum chip 10 is mounted, in which the interposer 20 includes a conductive wiring line CL 1 electrically connected to the quantum chip 10 , and a metal film 70 disposed in a part of the interposer 20 that is in contact with a sample stage 30 having a cooling function, and a mounting surface 21 of the interposer 20 on which the quantum chip 10 is mounted or an opposite surface 22 opposite to the mounting surface 21 includes a first area AR 11 and a second area AR 12 different from the first area AR 11 as viewed in a direction perpendicular to the mounting surface 21 or the opposite surface 22.
1. A quantum device comprising:
a quantum chip comprising a quantum circuit in which a resonator is formed, the resonator comprising a loop circuit in which pieces of a superconducting material are connected to each other by a Josephson junction; and
an interposer on which the quantum chip is mounted, wherein
the interposer comprises a conductive wiring line electrically connected to the quantum chip, and a metal film disposed in a part of the interposer that is in contact with a sample stage having a cooling function, and
a mounting surface of the interposer on which the quantum chip is mounted or an opposite surface opposite to the mounting surface includes a first area and a second area different from the first area as viewed in a direction perpendicular to the mounting surface or the opposite surface,
the conductive wiring line is disposed in the first area of the mounting surface or the opposite surface,
the metal film is disposed in the second area of the mounting surface or the opposite surface, and
the metal film is formed in a square frame shape surrounding the first area.
2. The quantum device according to claim 1 , wherein the metal film contains at least any one of copper, silver, gold, platinum, and an alloy containing at least one of copper, silver, gold, or platinum.
3. The quantum device according to claim 1 , wherein the metal film is connected to the sample stage so that the metal film has a potential specified in the sample stage.
4. The quantum device according to claim 1 , wherein
the second area surrounds the first area, and
the metal film comprises a continuous solid film.
5. The quantum device according to claim 1 , wherein
the second area surrounds the first area, and
the metal film comprises a plurality of pieces of a solid film with slits interposed therebetween.
6. The quantum device according to claim 1 , wherein
the second area surrounds the first area, and
the metal film comprises a patterned film having a predetermined punched pattern.
7. The quantum device according to claim 1 , wherein
the second area surrounds the first area, and
the metal film comprises a plurality of dot-like pieces of a film.
8. A quantum device comprising:
a quantum chip comprising a quantum circuit in which a resonator is formed, the resonator comprising a loop circuit in which pieces of a superconducting material are connected to each other by a Josephson junction; and
an interposer on which the quantum chip is mounted, wherein
the interposer comprises a conductive wiring line electrically connected to the quantum chip, and a metal film disposed in a part of the interposer that is in contact with a sample stage having a cooling function, and
a mounting surface of the interposer on which the quantum chip is mounted or an opposite surface opposite to the mounting surface includes a first area and a second area different from the first area as viewed in a direction perpendicular to the mounting surface or the opposite surface,
the conductive wiring line is disposed in the first area of the mounting surface or the opposite surface, and
the metal film is disposed in the second area of the mounting surface or the opposite surface,
wherein
the quantum chip is disposed inside a recessed part formed in a predetermined surface of the sample stage, and
a part of the mounting surface of the interposer on which the quantum chip is mounted is in contact with the predetermined surface.
9. The quantum device according to claim 8 , wherein at least a part of a side surface of the interposer is in contact with a plurality of pressing members provided on the predetermined surface.
10. The quantum device according to claim 9 , wherein
the interposer has a rectangular shape as viewed in a direction perpendicular to the mounting surface, and
flat-surface parts of the plurality of pressing members press parts of side surfaces of the interposer near respective corners thereof.
11. The quantum device according to claim 8 , wherein
the quantum chip includes a first surface and a second surface opposite to the first surface, the first surface being a surface that is opposed to the interposer when the quantum chip is mounted on the interposer, and
at least a part of the second surface is in contact with an inner surface of the recessed part.
12. The quantum device according to claim 8 , wherein
the quantum chip includes a first surface and a second surface opposite to the first surface, the first surface being a surface that is opposed to the interposer when the quantum chip is mounted on the interposer, and
at least a part of the second surface is bonded or joined to an inner surface of the recessed part.
13. The quantum device according to claim 8 , wherein
the quantum chip includes a first surface and a second surface opposite to the first surface, the first surface being a surface that is opposed to the interposer when the quantum chip is mounted on the interposer, and
the second surface is disposed in such a manner that a space is formed between the second surface and an inner surface of the recessed part.
14. The quantum device according to claim 8 , wherein
the quantum chip includes a first surface and a second surface opposite to the first surface, the first surface being a surface that is opposed to the interposer when the quantum chip is mounted on the interposer, and
the second surface is in contact with a chip pin movable relative to the sample stage so as to protrude from the inner surface of the recessed part.
15. The quantum device according to claim 8 , wherein
a recess is formed at a bottom of the recessed part, and
an area in which the quantum circuit is formed is contained in an area of the recess as viewed in a direction perpendicular to the first surface of the quantum chip, the first surface being the surface that is opposed to the interposer when the quantum chip is mounted on the interposer.
16. The quantum device according to claim 15 , wherein the quantum chip is in contact with a pillar extending from the bottom of the recessed part in a direction perpendicular to the first surface.
17. The quantum device according to claim 8 , wherein
a through hole is formed at a bottom of the recessed part, and
an area in which the quantum circuit is formed is contained in an area of the through hole as viewed in a direction perpendicular to the first surface of the quantum chip, the first surface being the surface that is opposed to the interposer when the quantum chip is mounted on the interposer.
18. The quantum device according to claim 8 , wherein
the recessed part is formed in a predetermined surface of the sample stage,
a stepped surface comprising a step with respect to the predetermined surface is formed around a mouth of the recessed part, and
a part of the mounting surface of the interposer on which the quantum chip is mounted is in contact with the stepped surface.
19. A quantum device comprising:
a quantum chip comprising a quantum circuit in which a resonator is formed, the resonator comprising a loop circuit in which pieces of a superconducting material are connected to each other by a Josephson junction; and
an interposer on which the quantum chip is mounted, wherein
the interposer comprises a conductive wiring line electrically connected to the quantum chip, and a metal film disposed in a part of the interposer that is in contact with a sample stage having a cooling function, and
a mounting surface of the interposer on which the quantum chip is mounted or an opposite surface opposite to the mounting surface includes a first area and a second area different from the first area as viewed in a direction perpendicular to the mounting surface or the opposite surface,
the conductive wiring line is disposed in the first area of the mounting surface or the opposite surface, and
the metal film is disposed in the second area of the mounting surface or the opposite surface,
wherein
the interposer includes a mounting surface on which the quantum chip is mounted, and an opposite surface opposite to the mounting surface,
the interposer comprises an interposer substrate, and a thermal via extending from a mounting surface side of the interposer substrate to the opposite surface side thereof, and
the thermal via comprises a tapered part in which a diameter on the opposite surface side is larger than that on the mounting surface side.