Hermetically sealed silicon micro-machined electromechanical system (MEMS) device having diffused conductors

Abstract

The present invention is an apparatus and method for a micro-machined electromechanical system (MEMS) device having a hermetically sealed sensor or actuator device mechanism that is electrically interconnected by diffused conductive paths to a plurality of wire bond pads that are located external to the hermetic seal.

1 - 22 . (canceled)  
     
     
         23 . A method for fabricating a micro-machined electromechanical system (MEMS) device, the method comprising: 
 micro-machining an electromechanical device mechanism in a semiconductor silicon wafer;    diffusing a channel of electrically conductive impurities into one surface of semiconductor silicon wafer between the device mechanism and a portion of the semiconductor silicon wafer remote from the device mechanism, one end of the channel of electrically conductive impurities being in electrical contact with the device mechanism;    depositing a metallic electrical conductor on the surface of the semiconductor silicon wafer in the remote portion of the semiconductor silicon wafer and in electrical contact with a second end of the channel of electrically conductive impurities;    micro-machining a first cover plate sized to cover the sensor mechanism and a portion of the channel of electrically conductive impurities; and    bonding the device mechanism to the first cover plate, the first cover plate further exposing at least a portion of the metallic electrical conductor.    
     
     
         24 . The method of  claim 23  wherein diffusing a channel of electrically conductive impurities into one surface of semiconductor silicon wafer further comprises diffusing the impurities to a predetermined depth.  
     
     
         25 . The method of  claim 23  wherein diffusing a channel of electrically conductive impurities into one surface of semiconductor silicon wafer further comprises diffusing one of p-type dopants and n-type dopants as a function of a base material forming the semiconductor silicon wafer.  
     
     
         26 . The method of  claim 23  wherein depositing the metallic electrical conductor in electrical contact with the channel of electrically conductive impurities further comprises providing a contact window at the second end of the channel.  
     
     
         27 . The method of  claim 23  wherein: 
 micro-machining the cover plate further comprises micro-machining a window aperture therein; and    bonding the device mechanism to the first cover plate with the first cover plate further exposing at least a portion of the metallic electrical conductor further comprises aligning the window aperture with the metallic electrical conductor.    
     
     
         28 . The method of  claim 23  wherein bonding the device mechanism to the first cover plate further comprises adhesively, electrostatically, eutectically, anodically or fusion bonding the first cover plate to the surface of the semiconductor silicon wafer having the metallic electrical conductor deposited thereon.  
     
     
         29 . The method of  claim 23  wherein micro-machining an electromechanical device mechanism in a semiconductor silicon wafer further comprises micro-machining one of an electromechanical sensor and an electromechanical actuator.  
     
     
         30 . The method of  claim 23 , further comprising: 
 micro-machining a second cover plate sized to cover the sensor mechanism; and    bonding the device mechanism between the first and second cover plates.    
     
     
         31 . The method of  claim 30  wherein bonding the sensor mechanism between the first and second cover plates further comprises hermetically sealing the device mechanism.