Methods and Apparatuses for Integrated Packaging of Microelectromechanical Devices

Abstract

Microelectromechanical systems (MEMS) packages, packaged MEMS devices, and methods for making the same are disclosed. The method may include forming a chamber sacrificial layer above an insulating layer that is coupled to a wafer. The method further may include forming a packaging layer above the chamber sacrificial layer. The method additionally may include forming one or more openings through the packaging layer. The method also may include removing the chamber sacrificial layer through the one or more openings. The method may include forming a sealing layer above the packaging layer such that the sealing layer substantially seals the one or more openings to form a hermetic cavity.

1 . A method of packaging a microelectromechanical systems (MEMS) device, comprising:
 forming a chamber sacrificial layer above an insulating layer that is coupled to a wafer;   forming a packaging layer above the chamber sacrificial layer;   forming one or more openings through the packaging layer;   removing the chamber sacrificial layer through the one or more openings; and   forming a sealing layer above the packaging layer such that the sealing layer substantially seals the one or more openings to form a hermetic cavity, where the sealing layer is formed with a material such that the material does not substantially leak into the hermetic cavity.   
     
     
         2 . The method of  claim 1 , further comprising:
 forming the insulating layer before forming the chamber sacrificial layer.   
     
     
         3 . The method of  claim 1 , where the insulating layer is selected from the group consisting of SiO 2 , Si 3 N 2 , and Al 2 O 3 . 
     
     
         4 . The method of  claim 1 , further comprising:
 forming a resonator above the insulating layer comprising:
 forming one or more conductive layers above the insulating layer; 
 forming a gap sacrificial layer above the one or more conductive layers; 
 forming a resonator beam above the gap sacrificial layer after forming the one or more conductive layers; and 
 removing the gap sacrificial layer to form an air gap under the resonator beam; 
   where forming the resonator is performed prior to forming the chamber sacrificial layer.   
     
     
         5 . The method of  claim 4 , where the one or more conductive layers comprises a first anchor, an electrode, and a second anchor. 
     
     
         6 . The method of  claim 4 , where the one or more conductive layers comprise a titanium layer and a gold layer. 
     
     
         7 . The method of  claim 4 , where removing the gap sacrificial layer comprises plasma ashing. 
     
     
         8 . The method of  claim 1 , where forming the packaging layer comprises depositing Al 2 O 3 . 
     
     
         9 . The method of  claim 1 , where removing the gap sacrificial layer comprises plasma ashing. 
     
     
         10 . The method of  claim 1 , where forming the sealing layer comprises forming a layer of Al 2 O 3  at a pressure of less than 10 Torr. 
     
     
         11 . The method of  claim 4 , further comprising:
 etching the sealing layer to expose a portion of one or more bond pads in the one or more conductive layers.