Microfabricated air bridges for planar microwave resonator circuits
View Patent ↗The present invention provides a process and structure of microfabricated air bridges for planar microwave resonator circuits. In an embodiment, the invention includes depositing a superconducting film on a surface of a base material, where the superconducting film is formed with a compressive stress, where the compressive stress is higher than a critical buckling stress of a defined structure, etching an exposed area of the superconducting film, thereby creating the at least one bridge, etching the base material, thereby forming a gap between the at least one bridge and the base material, depositing the at least one metal line on at least part of the superconducting film and at least part of the base material, where the at least one metal line runs under the bridge.
1. A process comprising:
depositing a superconducting film on a surface of a base material,
wherein the superconducting film is formed with a compressive stress,
wherein the compressive stress is higher than a critical buckling stress of a defined structure;
forming a first photoresist pattern on the superconducting film,
wherein the photoresist pattern defines at least one bridge;
etching an exposed area of the superconducting film, thereby creating the at least one bridge;
etching the base material, thereby forming a gap between the at least one bridge and the base material;
forming a second photoresist pattern on at least a defined surface of the base material,
wherein the second photoresist pattern defines a space for at least one metal line;
cleaning at least a part of the surface of the superconducting film;
depositing the at least one metal line on at least part of the superconducting film and at least part of the base material,
wherein the at least one metal line connects a first part of the superconducting film and a second part of the superconducting film,
wherein the at least one metal line runs under the bridge; and
removing the second photoresist pattern.
2. The process of claim 1 further comprising pulling the at least one bridge away from the base material.
3. The process of claim 2 , wherein the pulling comprises pulling the at least one bridge away from the base material by using electrostatic force.
4. The process of claim 1 , wherein the depositing the at least one metal line is performed by evaporation.
5. The process of claim 1 ,
wherein the first photo resist pattern defines a set of one or more holes,
wherein the set of one or more holes is sized such that the base material can be etched through the one or more holes, and
wherein the set of one or more holes is sized such that metal cannot be deposited through the set of one or more holes.
6. The process of claim 1 ,
wherein the first photo resist pattern defines a set of one or more holes,
wherein the set of one or more holes is sized such that metal can be deposited through the set of one or more holes.
7. The process of claim 1 , wherein the base material is silicon.
8. The process of claim 1 , wherein the superconducting film comprises a material selected from the group consisting of aluminum and niobium.
9. The process of claim 1 , wherein the at least one metal line is aluminum.
10. A process comprising:
depositing a first superconducting film on a surface of a base material;
depositing a second superconducting film on a surface of the first superconducting film,
wherein the second superconducting film is formed with a compressive stress,
wherein the compressive stress is higher than a critical buckling stress of a defined structure;
forming a first photoresist pattern on the second superconducting film,
wherein the photoresist pattern defines at least one bridge,
etching an exposed area of the second superconducting film, thereby creating the at least one bridge;
etching the first superconducting film, thereby forming a gap between the at least one bridge and the base material;
forming a second photoresist pattern on at least a defined surface of the base material,
wherein the second photoresist pattern defines a space for at least one metal line;
cleaning at least a part of a surface of the second superconducting film;
depositing the at least one metal line on at least part of the second superconducting film and at least part of the base material,
wherein the at least one metal line connects a first part of the second superconducting film and a second part of the second superconducting film,
wherein the at least one metal line runs under the bridge; and
removing the second photoresist pattern.
11. The process of claim 10 further comprising pulling the at least one bridge away from the base material.
12. The process of claim 11 , wherein the pulling comprises pulling the at least one bridge away from the base material by using electrostatic force.
13. The process of claim 10 , wherein the depositing the at least one metal line is performed by evaporation.
14. The process of claim 10 ,
wherein the first photo resist pattern defines a set of one or more holes,
wherein the set of one or more holes is sized such that the base material can be etched through the one or more holes, and
wherein the set of one or more holes is sized such that aluminum cannot be deposited through the set of one or more holes.
15. The process of claim 10 ,
wherein the first photo resist pattern defines a set of one or more holes,
wherein the set of one or more holes is sized such that metal can be deposited through the set of one or more holes.
16. The process of claim 10 , wherein the base material is silicon.
17. The process of claim 10 , wherein first superconducting film comprises a material selected from the group consisting of aluminum and niobium.