Integrated structure with bifunctional routing and assembly comprising such a structure
An integrated structure intended to connect a plurality of semiconductor devices, the integrated structure including a substrate, a first face and a second face, the first face being intended to receive the semiconductor devices, the integrated structure including, at the first face, at least one routing level, the routing level or levels including: at least one first conductor routing track in a conductor material; and at least one first superconductor routing track made from a superconductor material.
1. An integrated structure intended to connect a plurality of semiconductor devices, the integrated structure comprising a substrate, a first face and a second face, the first face being intended to receive the semiconductor devices, the integrated structure comprising, at the first face, at least one routing level, the at least one routing level comprising:
at least one first conductor routing track made from a non-superconductor conductor material; and
at least one first superconductor routing track made from a superconductor material, the at least one first superconductor routing track being spaced apart from the at least one first conductor routing track by a dielectric material in said at least one routing level,
the integrated structure comprising a plurality of routing levels, the routing levels of the plurality of routing levels being connected, between routing tracks, by inter-level vias so that conductor routing tracks of the plurality of routing levels are connected by inter-level conductor vias and superconductor routing tracks of the plurality of routing levels are connected by inter-level superconductor vias.
2. The integrated structure according to claim 1 , wherein each routing track of the first routing level of the plurality of routing levels is a superconductor routing track.
3. The integrated structure according to claim 1 , comprising a plurality of non-superconductor conductor through vias to connect, from the second face of the integrated structure, the non-superconductor conductor routing tracks located on the first face of the integrated structure.
4. An assembly comprising an integrated structure according to claim 1 and at least one semiconductor device, the semiconductor device comprising a front face and a rear face, the rear face comprising at least one non-superconductor conductor routing track and a superconductor routing track, the assembly also comprising a first connection device connecting the non-superconductor conductor routing tracks of the integrated structure to the non-superconductor conductor routing tracks of the semiconductor device and second connection device connecting the superconductor routing tracks of the integrated structure to the superconductor routing tracks of the semiconductor device.
5. The assembly according to claim 4 , wherein the first connection device includes non-superconductor conductor bumps and the second connection means includes superconductor bumps.
6. The assembly according to claim 4 , wherein the first connection device includes pads made from a non-superconductor conductor material and the second connection device includes pads made from a superconductor material.
7. The assembly according to claim 4 , wherein the first connection includes pads comprising:
a first layer of a non-superconductor conductor material;
a second layer of a superconductor conductor material; and
a third layer of a non-superconductor conductor material;
and wherein the second connection device includes pads formed in a superconductor material.
8. A method of assembly between an integrated structure according to claim 1 and a semiconductor device, the integrated structure comprising, on its first face, a first plurality of non-superconductor conductor connection pads and a first plurality of superconductor connection pads, the semiconductor device comprising a front face and a rear face, the rear face comprising a second plurality of non-superconductor conductor connection pads configured in such a way as to be able to be facing the first plurality of non-superconductor conductor connection pads and a second plurality of superconductor connection pads configured in such a way as to be able to be placed facing the first plurality of superconductor connection pads, said connection pads being formed in a layer of a dielectric material, the method comprising, carried out at the first face of the integrated structure and at the rear face of the semiconductor device:
a step of chemical mechanical polishing to the surface of the layer of a dielectric material present on the first face of the integrated structure and on the rear face of the semiconductor device;
a step of putting the first face of the integrated structure in contact with the rear face of the semiconductor device, the connection pads of the integrated structure being put into correspondence with the connection pads of the semiconductor device;
a step of annealing or thermocompression in such a way as to glue the connection pads together.
9. The method according to claim 8 , comprising, before the step of chemical mechanical polishing:
a step of selective etching of the connection pads in such a way as to form a recess with respect to the surface of the layer of a dielectric material wherein the connection pads are formed;
a step of depositing a layer of a superconductor material, the thickness of the layer deposited being comprised between 50 and 100 nm;
a layer of a superconductor material thus being formed on each connection pad, the connection pads being glued together, during the step of annealing or thermocompression, via this layer of a superconductor material.
10. A system comprising a printed circuit and an assembly according to claim 4 , the assembly being connected to the printed circuit via the integrated structure of said assembly, the assembly comprising at least one first semiconductor device in the form of a functional chip and a second semiconductor device in the form of a control chip, the control chip being connected to the functional chip via the integrated structure by superconductor routing tracks.
11. The system according to claim 10 , wherein the functional chip comprises:
a substrate comprising a first face and a second face, the second face of the substrate forming the front face of the functional chip;
a first oxide layer on the first face of the substrate;
a second oxide layer on the first oxide layer;
a first routing level formed on the surface of the second oxide layer in contact with the first oxide layer;
a third oxide layer on the second oxide layer wherein at least one semiconductor component is inserted;
a rear face formed by the surface of the third oxide layer opposite the second oxide layer, the rear face comprising a plurality of superconductor routing tracks surrounded at least partially by one or more non-conductor conductor routing tracks, the semiconductor component being connected to the superconductor routing tracks via superconductor vias and the non-superconductor conductor routing tracks of the rear face being connected to the routing level via non-superconductor conductor vias.
12. The system according to claim 11 , wherein the semiconductor component is a qubit.
13. The system according to claim 12 , wherein the qubit is a silicon spin qubit.