Sensor package and method of forming same

Abstract

A method ( 70 ) of forming sensor packages ( 20 ) entails providing a sensor wafer ( 74 ) having sensors ( 30 ) formed on a side ( 26 ) positioned within areas ( 34 ) delineated by bonding perimeters ( 36 ), and providing a controller wafer ( 82 ) having control circuitry ( 42 ) at one side ( 38 ) and bonding perimeters ( 46 ) on an opposing side ( 40 ). The bonding perimeters ( 46 ) of the controller wafer ( 82 ) are bonded to corresponding bonding perimeters ( 36 ) of the sensor wafer ( 74 ) to form a stacked wafer structure ( 48 ) in which the control circuitry ( 42 ) faces outwardly. The controller wafer ( 82 ) is sawn to reveal bond pads ( 32 ) on the sensor wafer ( 74 ) which are wire bonded to corresponding bond pads ( 44 ) formed on the same side ( 38 ) of the wafer ( 82 ) as the control circuitry ( 42 ). The structure ( 48 ) is encapsulated in packaging material ( 62 ) and is singulated to produce the sensor packages ( 20 ).

What is claimed is: 
     
         1 - 20 . (canceled) 
     
     
         21 . A sensor package comprising:
 a sensor element die having a first side and a second side opposite said first side, said first side including a first sensor positioned within an area on said first side delineated by a first bonding perimeter, and said first side further including first bond pads positioned outside of said area;   a controller element die having a third side and a fourth side opposite said third side, said third side including control circuitry and second bond pads, and said fourth side including a second bonding perimeter and sensor features, wherein said second bonding perimeter is bonded to said first bonding perimeter to form a stacked structure, and wherein said sensor features comprise functional components of said first sensor; and   bond wires attached between corresponding ones of said first bond pads on said first side of said sensor element die and said second bond pads on said third side of said controller element die.   
     
     
         22 . The sensor package of  claim 21  wherein said sensor features include a cavity, said cavity extending into said controller wafer from said fourth side such that said cavity is aligned with said first sensor. 
     
     
         23 . The sensor package of  claim 21  wherein said sensor features include electrodes aligned with said first sensor. 
     
     
         24 . The sensor package of  claim 21  wherein at least said fourth side of said controller element die and said first side of said sensor element die are co-aligned. 
     
     
         25 . The sensor package of  claim 21  further comprising a packaging material applied over said third side of said controller element die to encapsulate said control circuitry and said bond wires. 
     
     
         26 . The sensor package of  claim 25  wherein:
 said controller element die includes bump pads formed on said third side; and 
 said sensor package further includes conductive elements formed on said bump pads after said controller element die is bonded to said sensor element die, said conductive elements extending above said bump pads, and said packaging material at least partially encapsulating said conductive elements so that a top surface of said conductive elements is exposed from said packaging material. 
 
     
     
         27 . The sensor package of  claim 21  further comprising a sensor die mounted on said third side of said controller element die. 
     
     
         28 . The sensor package of  claim 21  further comprising an integral sensor internal to said controller element die or a sensor die mounted on said third side of said controller element die. 
     
     
         29 . A sensor package comprising:
 a sensor element die having a first side and a second side opposite said first side, said first side including a first sensor positioned within an area on said first side delineated by a first bonding perimeter, and said first side further including first bond pads positioned outside of said area;   a controller element die having a third side and a fourth side opposite said third side, said third side including control circuitry and second bond pads, and said fourth side including a second bonding perimeter and sensor features, wherein said second bonding perimeter is bonded to said first bonding perimeter to form a stacked structure, and wherein said sensor features comprise functional components of said sensor;   a second sensor die mounted on said third side of said controller element die;   bond wires attached between corresponding ones of said first bond pads on said first side of said sensor element die and said second bond pads on said third side of said controller element die; and   a packaging material applied over said third side of said controller element die to encapsulate said control circuitry, said second sensor die, and said bond wires.   
     
     
         30 . The sensor package of  claim 29  wherein said sensor features include a cavity, said cavity extending into said controller wafer from said fourth side such that said cavity is aligned with said sensor. 
     
     
         31 . The sensor package of  claim 29  wherein said sensor features include at least one electrode aligned with said sensor. 
     
     
         32 . The sensor package of  claim 29  wherein:
 said controller element die includes bump pads formed on said third side; and 
 said sensor package further includes conductive elements formed on said bump pads after said controller element die is bonded to said sensor element die, said conductive elements extending above said bump pads, and said packaging material at least partially encapsulating said conductive elements so that a top surface of said conductive elements is exposed from said packaging material. 
 
     
     
         33 . The sensor package of  claim 32  wherein said conductive elements extend a first height above said third side of said controller element die, said second sensor die extends a second height above said third side of said controller element die, and said second height is less than said first height. 
     
     
         34 . The sensor package of  claim 29  further comprising an integral sensor internal to said controller element die.