Methods and apparatus for a packaged MEMS switch
A micro-electro mechanical system (NEMS) device, such as a MEMS switch ( 100 ), includes a package seal ( 104 ) bonded to a substrate ( 102 ), wherein an electrode 106 (e.g., an actuation electrode associated with a switch) is provided on an inner surface ( 103 ) of the package seal ( 104 ). The MEMS switch ( 100 ) might include, for example, a central switch structure implementing a double-pole, single-throw switch using a push-pull arrangement of internal activation electrodes ( 106, 108 ). The central switch structure might include a cantilevered moveable actuation electrode ( 122 ) or an electrode supported in two or more peripheral regions.
1 . A MEMS switch device comprising:
a substrate;
a package seal coupled to the substrate and having a surface internal to the MEMS device; and
a first actuation electrode formed on the surface of the package seal.
2 . The device of claim 1 , wherein the MEMS switch comprises a single-pole, double-throw switch.
3 . The device of claim 1 , wherein the MEMS switch further includes:
a second actuation electrode adjacent the first actuation electrode, wherein the second actuation electrode is a cantilever structure having a proximate end mechanically coupled to the substrate and a distal end moveable with respect to the substrate.
4 . The device of claim 3 , further including a third actuation electrode formed on the substrate opposite the first actuation electrode, a first transmission line contact formed on the surface of the package seal, a second transmission line contact formed on the substrate opposite the first transmission line contact, and a shorting bar mechanically coupled to the distal end of the second actuation electrode.
5 . The device of claim 4 , wherein the first actuation electrode and the second actuation electrode are operative such that the shorting bar can be selectively brought into contact with the first transmission line contact through the application of a bias voltage across the first and second actuation electrodes.
6 . The device of claim 5 , wherein the second actuation electrode is formed between two dielectric mechanical layers.
7 . The device of claim 5 , wherein the second actuation electrode has a length dimension extending laterally along the cantilever structure and a width dimension substantially perpendicular to the length dimension, further wherein the width dimension is greater than the length dimension.
8 . The device of claim 1 , wherein the MEMS switch further includes:
a second actuation electrode adjacent the first actuation electrode, wherein the second actuation electrode has a first end mechanically coupled to the substrate, a second end mechanically coupled to the substrate, and a central region moveable with respect to the substrate.
9 . The device of claim 8 , further including a third actuation electrode formed on the substrate opposite the first actuation electrode, a first transmission line contact formed on the surface of the package seal, a second transmission line contact formed on the substrate opposite the first transmission line contact, and a shorting bar mechanically coupled to the central region of the second actuation electrode.
10 . The device of claim 9 , wherein the first actuation electrode and the second actuation electrode are operative such that the shorting bar can be selectively brought into contact with the first transmission line contact via application of a bias across the first and second actuation electrodes.
11 . The device of claim 9 , wherein the second actuation electrode is formed between two dielectric mechanical layers.
12 . A method for forming a MEMS switch device, comprising:
providing a substrate;
forming a central switch structure on the substrate, the central switch structure including a moveable actuation electrode;
forming a top actuation electrode above the moveable actuation electrode;
forming a package seal layer on the stationary actuation electrode.
13 . The method of claim 12 , wherein forming the central switch structure includes forming a cantilevered structure comprising two dielectric layers with the moveable actuation electrode formed therebetween.
14 . The method of claim 12 , further comprising:
forming a bottom actuation electrode and a bottom transmission line contact on the substrate;
forming a first sacrificial layer one the bottom actuation electrode and the bottom transmission line contact;
forming a top transmission line contact adjacent the top actuation electrode;
forming a second sacrificial layer on the central switch structure;
forming the top actuation electrode and a top transmission line contact on the second sacrificial layer;
forming a first portion of the package seal layer on the top actuation electrode and the top transmission line contact; and
removing the first sacrificial layer and the second sacrificial layer.
15 . The method of claim 14 , further including forming a second portion of the package seal layer after removing the first sacrificial layer and the second sacrificial layer.
16 . A MEMS switch comprising:
a substrate having a bottom transmission line contact and a bottom activation electrode;
a package seal coupled to the substrate and having a top transmission line contact and a top activation electrode;
a central switch structure provided between the substrate and the package seal, wherein the central switch includes a moveable activation electrode and a moveable transmission line contact, and wherein the central switch structure is configured to have a first throw mode and a second throw mode, the first throw mode corresponding to electrical contact between the moveable activation electrode and the first transmission line contact, and the second throw mode corresponding to electrical contact between the moveable activation electrode and the second transmission line contact.
17 . The switch of claim 16 , wherein the top actuation electrode and the bottom actuation electrode are operative in a push-pull manner with respect to the moveable actuation electrode such that the central switch structure can be selectively placed in the first throw mode and the second throw mode via application of a bias to the top and bottom actuation electrodes.
18 . The switch of claim 16 , wherein the central switch structure includes at least one dielectric layer mechanically coupled to the moveable actuation electrode.
19 . The switch of claim 16 , wherein the central switch structure is a cantilevered structure mechanically coupled to the substrate.
20 . The switch of claim 16 , wherein the central switch structure includes a central moveable region and at least two peripheral regions mechanically coupled to the substrate.