Single use, robust, MEMS based electro-thermal microswitches for redundancy and system reconfiguration

A new type of single use MEMS based thermal microswitch is described and its performance results are presented. The device mechanically breaks a metallic line or locally solders two metallic lines. Switching between the two stable states (on or off) is accomplished by a current pulse through an integrated heater underneath the electrical lines to be interrupted or connected. Some key features are that switches are bistable, integratable and IC compatible. They are compatible with low voltage operation (5 V), no contact resistance (0 Ω for on–off and ∼0.008 Ω for off–on); they have low energy consumption during switching (3.5 mJ for on–off and 130 mJ for off–on); switching current is between 10 and 20 mA for on–off and between 50 and 70 mA for off–on. The minimum switching pulse width is 7 and 300 ms for on–off and off–on, respectively; operation in ambient environment may be possible; predicted lifetime is very long and therefore both switches can be used for long life systems. Batch fabrication using planar processing methods is used.