Multi-layer composite backplate for micromechanical microphone

Abstract

Backplates for MEMS devices. In one embodiment, the backplate includes an interconnect layer, a first layer, a second layer and a plurality of openings. The interconnect layer includes a first side and a second side that is opposite from the first side. The first layer is coupled to the first side of the interconnect layer. The second layer is coupled to the second side of the interconnect layer. The plurality of openings are located between a first side of the backplate and a second side of the backplate.

What is claimed is: 
     
         1 . A backplate for a MEMS device, the backplate comprising:
 an interconnect layer including a first side and a second side opposite the first side;   a first layer coupled to the first side of the interconnect layer;   a second layer coupled to the second side of the interconnect layer; and   a plurality of openings located between a first side of the backplate and a second side of the backplate.   
     
     
         2 . The backplate of  claim 1 , wherein the interconnect layer includes a plurality of discrete posts. 
     
     
         3 . The backplate of  claim 2 , wherein the each of the plurality of discrete posts has a shape selected from a group consisting of circular, triangular, square, and polygonal. 
     
     
         4 . The backplate of  claim 2 , wherein each of the plurality of discrete posts includes a core and a ring wall surrounding the core. 
     
     
         5 . The backplate of  claim 4 , wherein the core includes an oxide core. 
     
     
         6 . The backplate of  claim 1 , wherein the first layer or the second layer is an electrically conductive material, and wherein the interconnect layer is an electrically insulating material. 
     
     
         7 . The backplate of  claim 1 , wherein the first layer or the second layer is an electrically insulating material, and wherein the interconnect layer is an electrically conductive material. 
     
     
         8 . A backplate for a MEMS device, the backplate comprising:
 a plurality of openings;   a first layer;   a second layer; and   an interconnect layer positioned between the first layer and the second layer, the interconnect layer coupling the first layer to the second layer.   
     
     
         9 . The backplate of  claim 8 , wherein the interconnect layer includes two walls extending from the first layer to the second layer, and
 a region positioned between the two walls and extending from the first layer to the second layer.   
     
     
         10 . The backplate of  claim 9 , wherein the first layer or the second layer includes a release hole that is positioned adjacent to the region. 
     
     
         11 . The backplate of  claim 9 , wherein the region is hollow. 
     
     
         12 . The backplate of  claim 9 , wherein the two walls are constructed of a first material, and wherein the region is constructed of a second material. 
     
     
         13 . The backplate of  claim 8 , wherein the interconnect layer includes a plurality of discrete posts, and wherein each of the plurality of discrete posts includes a core and a ring wall surrounding the core. 
     
     
         14 . The backplate of  claim 13 , wherein the first layer or the second layer includes a release hole that is positioned adjacent to the core. 
     
     
         15 . A backplate for a MEMS device, the backplate comprising:
 a plurality of openings;   a first layer; and   an interconnect layer coupled to the first layer and including a first portion, and
 a second portion positioned between the first portion and the first layer, wherein a width of the second portion is different than a width of the first portion. 
   
     
     
         16 . The backplate of  claim 15 , wherein a width of the first layer is equal to the width of the first portion. 
     
     
         17 . The backplate of  claim 15 , wherein the interconnect layer is constructed of a different material than the first layer. 
     
     
         18 . The backplate of  claim 15 , wherein the first layer is constructed of an electrically conductive material, and wherein the interconnect layer is constructed of an electrically insulating material.