Process for fabricating monolithic membrane substrate structures with well-controlled air gaps

Abstract

A process for fabricating monolithic membrane structures having air gaps is disclosed, comprising the steps of: providing a wafer; depositing and patterning a protective layer on the wafer; providing a trench in the wafer; depositing and patterning a metal in the trench; depositing and patterning a sacrificial layer on the metal; depositing and patterning a membrane pad on the sacrificial layer; providing a polymeric film on the protective layer and sacrificial layer, wherein part of the polymeric film has a tensile stress; and releasing part of the polymeric film from the protective layer and sacrificial layer, wherein the tensile stress of a portion of the polymeric film releases the portion of the polymeric film from the wafer and generates the air gap.

1 - 52 . (canceled)  
   
   
       53 . A monolithic membrane-substrate structure, comprising: 
 a substrate having a trench, said trench having a trench depth;    a protective layer located on the substrate;    a layer of polymeric material located above the substrate and the protective layer;    a first intermediate layer located in said trench;    a second intermediate layer located under said layer of polymeric material and contacting said layer of polymeric material; and    an air gap between the layer of polymeric material and the substrate.    
   
   
       54 . A monolithic membrane-substrate structure, comprising: 
 a substrate having a first side;    a first protective layer disposed on the first side of the substrate;    a second protective layer disposed on the second side of the substrate;    a third protective layer disposed on the first side of the substrate;    a layer of polymeric material located above the first and third protective layer;    a first intermediate layer located above said third protective layer and contacting said third protective layer;    a second intermediate layer located under said layer of polymeric material and contacting said layer of polymeric material; and    an air gap between the layer of polymeric material and the substrate.