Microelectromechanical systems comprising differential inductors and methods for making the same
An integrated Microelectromechanical Systems (“MEMS”) device ( 100 ). The MEMS device comprises a substrate ( 200, 300 ), a transition portion ( 118 ), and a differential inductor ( 1000, 1100, 1300 ). The transition portion is connected to and at least partially extends transversely away from a major surface of the substrate. The differential inductor is mechanically suspended above a major surface of the substrate at least partially by the transition portion. The differential inductor is also electrically connected to an electronic circuit external thereto by the transition portion. A first dielectric gap exists between the major surface of the substrate and the differential inductor.
1. An integrated Microelectromechanical Systems (“MEMS”) device, comprising:
a substrate;
a transition portion connected to and at least partially extending transversely away from a major surface of the substrate;
a differential inductor mechanically suspended above a major surface of the substrate at least partially by the transition portion and electrically connected to an electronic circuit external thereto by the transition portion; and
a first dielectric gap between the major surface of the substrate and the differential inductor.
2. The integrated MEMS device according to claim 1 , wherein the electronic circuit is formed on the major surface of the substrate so as to reside between the substrate and the differential inductor, wherein a dielectric gap exists between the electronic circuit and the differential inductor.
3. The integrated MEMS device according to claim 1 , wherein a first conductive material used to fabricate the differential inductor has a first melting point that is different from second melting points of all second conductive materials used to form the electronic circuit by no more than 100° C.
4. The integrated MEMS device according to claim 1 , wherein the transition portion comprises a three dimensional hollow ground structure in which an elongate center conductor is suspended.
5. The integrated MEMS device according to claim 4 , wherein the elongated center conductor is separated from the three dimensional hollow ground structure via a dielectric gap on all sides.
6. The integrated MEMS device according to claim 4 , wherein the differential inductor has a first inductor port electrically connected to the three dimensional hollow ground structure of the transition portion and a second inductor port electrically connected to the elongated center conductor of the transition portion.
7. The integrated MEMS device according to claim 4 , wherein the differential inductor has a first inductor port and a second inductor port which are both electrically connected to the elongate center conductor of the transition portion.
8. The integrated MEMS device according to claim 1 , wherein a periphery of the differential inductor is separated from and at least partially surrounded by a ground structure of the transition portion.
9. The integrated MEMS device according to claim 8 , further comprising a magnetic material disposed between the differential inductor and the ground structure of the transition portion.
10. The integrated MEMS device according to claim 1 , wherein the differential inductor comprises a first coil portion defined by windings traveling along a first serpentine path in a direction towards a center of the differential inductor and a second coil portion defined by windings traveling along a serpentine path in a direction away from the center of the differential inductor.
11. The integrated MEMS device according to claim 10 , wherein the first coil portion and the second coil portion are electrically coupled to each other at the center of the differential inductor.
12. The integrated MEMS device according to claim 10 , wherein at least a portion of each winding of the second coil portion is disposed between two adjacent windings of the second coil portion.
13. The integrated MEMS device according to claim 12 , wherein at least a first winding portion of the first coil portion overlaps at least a second winding portion of the second coil portion such that a dielectric gap exists between the first and second winding portions.
14. The integrated MEMS device according to claim 1 , further comprising a magnetic material disposed between coil windings of the differential inductor.
15. A method of making an integrated Microelectromechanical Systems (“MEMS”) device, comprising:
forming an electronic circuit on a major surface of a substrate using a first conductive material having a first melting point;
forming a differential inductor structure on the major surface of the substrate using a second conductive material having a second melting point; and
removing at least one first resist layer from the MEMS filter structure to form (a) a differential inductor suspended over the major surface of the substrate at least partially by a transition portion electrically connecting the differential inductor to an electronic circuit, and (b) a first dielectric gap between the major surface of the substrate and the differential inductor.
16. The method according to claim 15 , wherein the electronic circuit is formed on the major surface of the substrate so as to reside between the substrate and the differential inductor, and wherein a dielectric gap exists between the electronic circuit and the differential inductor.
17. The method according to claim 15 , wherein the first and second melting points are different by no more than 100° C.
18. The method according to claim 15 , further comprising removing at least one second resist layer from the differential inductor structure such that the transition portion is defined by a three dimensional hollow ground structure in which an elongated center conductor is suspended.
19. The method according to claim 18 , wherein the elongated center conductor is separated from the three dimensional hollow ground structure via a dielectric gap on all sides.
20. The method according to claim 18 , further comprising electrically connecting a first inductor port of the differential inductor to the three dimensional hollow ground structure of the transition portion and electrically connecting a second inductor of the differential inductor to the elongate center conductor of the transition portion.
21. The method according to claim 18 , further comprising electrically connecting a first inductor port and a second inductor port of the differential inductor to the elongate center conductor of the transition portion.
22. The method according to claim 15 , further comprising surrounding at least a portion of a periphery of the differential inductor by a ground structure of the transition portion.
23. The method according to claim 22 , further comprising disposing a magnetic material between the differential inductor and the ground structure of the transition portion.
24. The method according to claim 15 , wherein the differential inductor comprises a first coil portion defined by windings traveling along a first serpentine path in a direction towards a center of the differential inductor and a second coil portion defined by windings traveling along a serpentine path in a direction away from the center of the differential inductor.
25. The method according to claim 24 , wherein the first coil portion and the second coil portion are electrically coupled to each other at the center of the differential inductor.
26. The method according to claim 24 , wherein at least a portion of each winding of the second coil portion is disposed between two adjacent windings of the second coil portion.
27. The method according to claim 26 , wherein at least a first winding portion of the first coil portion overlaps at least a second winding portion of the second coil portion such that a dielectric gap exists between the first and second winding portions.
28. The method according to claim 15 , further comprising disposing a magnetic material between coil windings of the differential inductor.