Mems sensor with side port and method of fabricating same

Abstract

A MEMS sensor package comprises a MEMS die that includes a substrate having a sensor formed thereon and a cap layer coupled to the substrate. The cap layer has a cavity overlying a substrate region at which the sensor resides. A port extends between the cavity and a side wall of the MEMS die and enables admittance of fluid into the cavity. Fabrication methodology entails providing a substrate structure having sensors formed thereon, providing a cap layer structure having inwardly extending cavities, and forming a channel between pairs of the cavities. The cap layer structure is coupled with the substrate structure and each channel is interposed between a pair of cavities. A singulation process produces a pair of sensor packages, each having a port formed by splitting the channel, where the port is exposed during singulation and extends between its respective cavity and side wall of the sensor package.

1 . A microelectromechanical systems (MEMS) sensor package comprising:
 a MEMS die, said MEMS die comprising:
 a substrate having a first inner surface and a first outer surface; 
 a MEMS sensor formed on said first inner surface; and 
 a cap layer having a second inner surface and a second outer surface, wherein said second inner surface of said cap layer is coupled to said first inner surface of said substrate, said cap layer includes a cavity extending inwardly from said second inner surface and overlying a region of said first inner surface of said substrate, said MEMS sensor resides in said cavity at said region of said first inner surface of said substrate, and a port extends between said cavity and a side wall of said MEMS die, said side wall extending between said first outer surface of said substrate and said second outer surface of said cap layer; and 
   an encapsulant covering said MEMS die, wherein said encapsulant is absent from said side wall and said encapsulant does not obstruct said port.   
     
     
         2 . The MEMS sensor package of  claim 1  wherein said port is configured to admit a fluid external to said cavity into said cavity. 
     
     
         3 . (canceled) 
     
     
         4 . The MEMS sensor package of  claim 1  wherein said substrate has a recess formed therein, and said MEMS die further comprises a cantilevered platform structure having a platform and an arm extending from said platform, wherein said platform and said arm are suspended over said recess, said arm is fixed to said substrate, and said platform includes said region at which said MEMS sensor resides. 
     
     
         5 . The MEMS sensor package of  claim 4  wherein said arm is a sole attachment point of said platform to said substrate. 
     
     
         6 . The MEMS sensor package of  claim 1  further comprising a semiconductor die coupled to one of said first outer surface of said substrate and said second outer surface of said cap layer. 
     
     
         7 . The MEMS sensor package of  claim 6  further comprising conductive interconnects electrically coupling said MEMS sensor with said semiconductor die. 
     
     
         8 . The MEMS sensor package of  claim 1  wherein said MEMS sensor comprises a pressure sensor, said pressure sensor including a pressure deformable diaphragm disposed at said region of said first inner surface of said substrate. 
     
     
         9 - 17 . (canceled) 
     
     
         18 . A structure comprising:
 a substrate having a first inner surface and a first outer surface;   a MEMS pressure sensor formed on said first inner surface;   a cap layer having a second inner surface and a second outer surface; and   an encapsulant covering said substrate and said cap layer, wherein:
 said second inner surface of said cap layer is coupled to said first inner surface of said substrate; 
 said cap layer includes a cavity extending inwardly from said second inner surface and overlying a region of said first inner surface of said substrate; 
 said MEMS pressure sensor resides in said cavity and includes a pressure deformable diaphragm disposed at said region of said first inner surface of said substrate; 
 a port extends between said cavity and a side wall of said cap layer, said side wall extending between said first outer surface of said substrate and said second outer surface of said cap layer; 
 said encapsulant is absent from said side wall; and 
 said encapsulant does not obstruct said port. 
   
     
     
         19 . The structure of  claim 18  wherein said port is configured to admit a fluid external to said cavity into said cavity. 
     
     
         20 . The structure of  claim 18  wherein said MEMS pressure sensor is a first MEMS pressure sensor, said region is a first region, said cavity is a first cavity, said port is a first port, said side wall is a first side wall, said first MEMS pressure sensor residing in said first cavity is a first intermediate sensor structure and:
 said structure comprises a second MEMS pressure sensor at a second region of said first inner surface, said second region being laterally displaced from said first region; and 
 said cap layer includes a second cavity laterally displaced from said first cavity, wherein:
 said second cavity extends inwardly from said second inner surface and overlies a second region of said first inner surface; 
 said second MEMS pressure sensor resides in said second cavity at said second region of said first inner surface of said substrate to form a second intermediate sensor structure; 
 a channel extends inwardly from said second inner surface of said cap layer, said channel being interposed between said first and second cavities; 
 said first intermediate sensor structure is configured to be separated from said second intermediate sensor structure to produce a first MEMS pressure sensor package that includes said first MEMS pressure sensor having said first port and to produce a second MEMS pressure sensor that includes said second MEMS pressure sensor having a second port, said first port being a first portion of said channel, said second port being a second portion of said channel; and 
 said second port extends between said second cavity and a second side wall of said second MEMS sensor package, said second side wall extending between said first outer surface of said substrate and said second outer surface of said cap layer.