Trilayered beam MEMS device and related methods

• US 20040188785A1
• Filed: 04/02/2004
• Published: 09/30/2004
• Est. Priority Date: 11/09/2001
• Status: Active Grant

• Current Assignee: AAC Technologies Pte Limited (AAC Technologies Holdings Inc.)
• Original Assignee: Shawn Jay Cunningham, Svetlana Tatic-Lucic
• Inventors: Cunningham, Shawn Jay, Tatic-Lucic, Svetlana
• Granted Patent: US 6,917,086 B2
• Time in Patent Office: Days
• US Class Current: 257/415
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• CPC Class Codes: B81B 2201/018 Switches not provided for in B81B2201/014 - B81B2201/016
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81B 3/0024 Transducers for transforming thermal into mechanical energy or vice versa, e.g. thermal or bimorph actuators electric motors using thermal effects H02N10/00
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: B81C 1/0015 Cantilevers switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244
• CPC Class Codes: B81C 2201/0107 Sacrificial metal
• CPC Class Codes: B81C 2201/0108 Sacrificial polymer, ashing of organics
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: H01H 1/04 Co-operating contacts of different material
• CPC Class Codes: H01H 1/504 by thermal means
• CPC Class Codes: H01H 2001/0042 Bistable switches, i.e. having two stable positions requiring only actuating energy for switching between them, e.g. with snap membrane or by permanent magnet
• CPC Class Codes: H01H 2001/0063 having electrostatic latches, i.e. the activated position is kept by electrostatic forces other than the activation force
• CPC Class Codes: H01H 2001/0089 Providing protection of elements to be released by etching of sacrificial element; Avoiding stiction problems, e.g. of movable element to substrate
• CPC Class Codes: H01H 2059/0072 with stoppers or protrusions for maintaining a gap, reducing the contact area or for preventing stiction between the movable and the fixed electrode in the attracted position
• CPC Class Codes: H01H 2061/006 Micromechanical thermal relay
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01H 61/04 wherein the thermally-sensitive member is only heated directly
• CPC Class Codes: H01L 23/3735 : Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 23/522 : including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
• CPC Class Codes: H01L 27/1203 : the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H02N 1/006 : of the gap-closing type H02N1/004 takes precedence
• CPC Class Codes: H02N 10/00 : Electric motors using thermal effects motors using expansion or contraction of bodies due to heating or cooling F03G7/06
• CPC Class Codes: Y10T 29/49222 : forming array of contacts or terminals

Abstract

Trilayered Beam MEMS Device and Related Methods. According to one embodiment, a method for fabricating a trilayered beam is provided. The method can include depositing a sacrificial layer on a substrate and depositing a first conductive layer on the sacrificial layer. The method can also include forming a first conductive microstructure by removing a portion of the first conductive layer. Furthermore, the method can include depositing a structural layer on the first conductive microstructure, the sacrificial layer, and the substrate and forming a via through the structural layer to the first conductive microstructure. Still furthermore, the method can include the following: depositing a second conductive layer on the structural layer and in the via; forming a second conductive microstructure by removing a portion of the second conductive layer, wherein the second conductive microstructure electrically communicates with the first conductive microstructure through the via; and removing a sufficient amount of the sacrificial layer so as to separate the first conductive microstructure from the substrate, wherein the structural layer is supported by the substrate at a first end and is freely suspended above the substrate at an opposing second end.

Claims

1. A microscale structure, comprising:

(a) a substrate;

(b) a structural dielectric arm supported by the substrate and having upper and lower surfaces suspended above the substrate, and having a via registering with the upper and lower surfaces;

(c) a first conductive element contacting the lower surface; and

(d) a second conductive element contacting the upper surface and electrically communicating with the first conductive element through the via.

4. The switch according to claim 1, further including:

(a) a second conductive interconnect attached to the substrate;

(b) a second dielectric layer formed on the second conductive interconnect; and

(c) a second stationary contact attached to the second dielectric layer, having electrical communication with the second conductive interconnect, and positioned for contacting the movable contact simultaneously with the first stationary contact when the structural layer moves towards the first stationary contact, whereby the first and second conductive interconnects are in electrical communication through the movable contact and the first and second stationary contacts.

5. The switch according to claim 4, further including a contact interconnect formed on the top surface of the structural layer and in electrical communication with the movable contact.

6. The switch according to claim 5, wherein the movable contact includes a first and second contact portion attached to the contact interconnect and in electrical communication through the contact interconnect, wherein the first and second contact portions are positioned to contact the first and second stationary contacts, respectively, when the structural layer moves.

2. A microscale switch having a conductive interconnect, the switch comprising:

(a) a substrate having a first conductive interconnect and a stationary electrode;

(b) a first dielectric layer formed on the first conductive interconnect;

(c) a first stationary contact attached to the first dielectric layer and having electrical communication with the first conductive interconnect;

(d) a movable structural layer including a bottom surface suspended over the first stationary contact and a top surface opposing the bottom surface;

(e) a movable electrode attached to the bottom surface of the structural layer whereby the movable electrode is separated from the stationary electrode by a first gap;

(f) an electrode interconnect attached to the top surface of the structural layer and connected to the movable electrode for electrical communication; and

(g) a movable contact attached to the bottom surface of the structural layer whereby the movable contact is separated from the first stationary contact by a second gap and positioned to contact the first stationary contact when the structural layer moves towards the first stationary contact.

3. The switch according to claim 2, further including a contact interconnect formed on the top surface of the structural layer and in electrical communication with the movable contact.