Method of producing a topology-optimized electrode for a resonator in thin-film technology
View Patent ↗In a method of producing an electrode for a resonator in thin-film technology, the electrode of the resonator is embedded in an insulating layer such that a surface of the electrode is exposed, and that a surface defined by the electrode and the insulating layer is substantially planar.
1. A method of producing a resonator in thin-film technology, the resonator including a piezoelectric layer which is arranged at least partially between a lower electrode and an upper electrode, the resonator being formed on a substrate, the method comprising:
(a) producing the lower electrode of the resonator on the substrate;
(b) depositing an insulating layer on the surface of the substrate, with a thickness substantially equal to the thickness of the lower electrode;
(c) lifting off a portion of the insulating layer such that a surface of the lower electrode is exposed, and that a substantially planar surface defined by the lower electrode and a portion of insulating layer remaining is formed;
(d) depositing the piezoelectric layer on and in contact with the substantially planar surface; and
(e) producing the upper electrode on the piezoelectric layer.
2. The method as claimed in claim 1 , wherein the lifting off comprises lifting off the insulating layer such that a portion of the insulating layer outside of the lower electrode remains substantially unchanged.
3. The method as claimed in claim 2 , wherein the lifting off comprises the removal of the insulating layer above the lower electrode by chemical-mechanical polishing.
4. The method as claimed in claim 1 , wherein the lifting off comprises: etching a part of the insulating layer above the lower electrode using a mask, such that a portion of the upper surface of the lower electrode is exposed; and removing, using chemical-mechanical polishing, remaining portions of the insulating layer that are located above a plane defined by the surface of the lower electrode.
5. The method as claimed in claim 1 , wherein the insulating layer comprises a dielectric layer.
6. The method as claimed in claim 5 , wherein the dielectric layer comprises one of the group consisting of a silicon nitride layer and a silicon oxide layer.
7. The method as claimed in claim 1 , wherein the piezoelectric layer comprises one of the group consisting of AlN, ZnO and PZT.
8. The method as claimed in claim 1 , wherein the lower electrode and the upper electrode comprise at least one of the group consisting of aluminum and tungsten.
9. The method as claimed in claim 1 , wherein the resonator is a BAW resonator.
10. A method of producing a resonator in thin-film technology, the resonator including a piezoelectric layer which is arranged at least partially between a first electrode and a second electrode, the resonator being formed on a substrate, the method comprising:
(a) providing the first electrode of the resonator on the substrate;
(b) forming an insulating layer on the surface of the substrate, the insulating layer having a thickness at least as great as a thickness of the first electrode;
(c) removing a portion of the insulating layer such that a surface of the first electrode is exposed, and that a substantially planar surface defined by the first electrode and the insulating layer is formed;
(d) depositing the piezoelectric layer on and in contact with the substantially planar surface; and
(e) producing the second electrode on the piezoelectric layer.
11. The method as claimed in claim 10 , wherein the forming the insulating layer comprises depositing the insulating layer.
12. The method as claimed in claim 10 , wherein the removing comprises removing the insulating layer such that a portion of the insulating layer outside of the first electrode remains substantially unchanged.
13. The method as claimed in claim 12 , wherein the removing comprises the removal of the insulating layer above the electrode by chemical-mechanical polishing.
14. The method as claimed in claim 10 , wherein removing comprises: etching a part of the insulating layer above the first electrode using a mask, such that a portion of the upper surface of the first electrode is exposed; and removing, using chemical-mechanical polishing, remaining portions of the insulating layer that are located above a plane defined by the surface of the first electrode.
15. The method as claimed in claim 10 , wherein the insulating layer comprises a dielectric layer.
16. The method as claimed in claim 15 , wherein the dielectric layer comprises one of the group consisting of a silicon nitride layer and a silicon oxide layer.
17. The method as claimed in claim 16 , wherein the piezoelectric layer comprises one of the group consisting of AlN, ZnO and PZT.
18. The method as claimed in claim 10 , wherein the first electrode and the second electrode comprise at least one of the group consisting of aluminum and tungsten.
19. The method as claimed in claim 10 , wherein the resonator is a BAW resonator.
20. The method as claimed in claim 10 , wherein the piezoelectric layer comprises one of the group consisting of AlN, ZnO and PZT.