MEMs switching circuit and method for an implantable medical device

• US 20050115811A1
• Filed: 10/26/2004
• Published: 06/02/2005
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Receveur, Rogier, Marxer, Cornel
• Granted Patent: US 7,388,459 B2
• Time in Patent Office: Days
• US Class Current: 200/243
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3912 Output circuitry therefor, e.g. switches
• 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 59/0009 making use of micromechanics

Abstract

A bistable MEMS switch for use in selectively opening or closing electrical circuits included in an implantable medical device system is provided. The switch includes a central movable beam having a movable contact; a suspension system for supporting the movable beam and generating a contact force; an actuator for displacing the beam upon application of an activation signal, and a fixed contact for interfacing the movable contact when the switch is in a closed state. The switch is fabricated from a Si/SiO₂/Si wafer using photolithography, DRIE and sacrificial oxide etching followed by metalization of electrical contact points with a wear-resistant metal or alloy. An actuation layer may be fabricated from the silicon substrate layer of the wafer and the signal layer may be fabricated from the top silicon layer. The actuation layer and signal layer are thereby electrically decoupled and mechanically coupled by the intervening SiO₂ layer.

Claims

1. A MEMS switch comprising:

a movable beam;

means for supporting said movable beam;

actuating means for displacing said movable beam; and

contact means for interfering said movable beam based on the state of said switch.

2. The switch of claim 1 wherein said movable beam is disposed substantially centrally and includes a movable contact.

3. The switch of claim 2 wherein said movable beam includes a suspension system.

4. The switch of claim 1 wherein said actuation means includes an actuator for displacing said movable beam on application of activation signal.

5. The switch of claim 1 wherein said contact means includes a fixed structure.

6. The switch of claim 1 including an actuation layer.

7. The switch of claim 1 including a Si, SiO₂ and Si wafer.

8. The switch of claim 1 wherein an Si substrate layer forms an actuation layer, and an Si top layer forms a signal layer.

9. The switch of claim 8 wherein said actuation layer and said signal layer are electrically decoupled and mechanically coupled by an intervening SiO₂ layer.