Emi shielding with conductive epoxy

Abstract

Disclosed is a localized shield to protect integrated circuit (IC) components within a package module from electromagnetic interference (EMI). Conventional EMI shielding solutions, such as a compartment shield, protect an entire package but do not provide localized protection or grounding of IC components. To construct the EMI shield disclosed herein, a layer of conductive epoxy is deposited on an upper conductive surface of the IC component, then the component is encapsulated in mold compound. Excess mold compound is ground down to expose the epoxy layer, and a conformal shield layer is applied over the mold compound such that the conductive epoxy layer forms a ground path between the conformal shield and the conductive surface of the IC component.

What is claimed is: 
     
         1 . A shielded integrated circuit package comprising:
 a printed circuit board;   a semiconductor die mounted to the printed circuit board and having a conductive top surface;   a conductive adhesive layer provided on the conductive top surface;   an over-mold above the printed circuit board, the over-mold encasing a periphery of the semiconductor die while exposing at least a portion of a top surface of the conductive adhesive layer; and   a conformal metal shield over the over-mold and over the conductive adhesive layer, the conductive adhesive layer and the conformal metal shield forming a path from the semiconductor die to a ground reference.   
     
     
         2 . The shielded integrated circuit package of  claim 1  wherein the semiconductor die includes a surface-mount device. 
     
     
         3 . The shielded integrated circuit package of  claim 1  wherein the semiconductor die includes one or more of a surface acoustic wave filter, bulk acoustic wave filter, power amplifier, or a low-noise amplifier. 
     
     
         4 . The shielded integrated circuit package of  claim 1  wherein the conductive adhesive layer includes a conductive epoxy. 
     
     
         5 . The shielded integrated circuit package of  claim 1  wherein the conformal metal shield includes aluminum, copper, nickel, iron, tin, or zinc. 
     
     
         6 . The shielded integrated circuit package of  claim 1  wherein the conformal metal shield is configured to substantially attenuate radio frequency signals causing electromagnetic interference in the n77, n78, or n79 New Radio frequency bands. 
     
     
         7 . The shielded integrated circuit package of  claim 1  wherein the shielded integrated circuit package is configured as a ball grid array package. 
     
     
         8 . The shielded integrated circuit package of  claim 1  further comprising a plurality of bond wires forming a wire cage around the shielded integrated circuit package. 
     
     
         9 . A radio frequency packaged module comprising:
 a printed circuit board;   first and second semiconductor dies mounted to the printed circuit board;   a first conductive adhesive layer provided on a conductive top surface of the first semiconductor die and a second conductive adhesive layer provided on a conductive top surface of the second semiconductor die;   an over-mold above the printed circuit board, the over-mold encasing a periphery of each of the first and second semiconductor dies while exposing at least a portion of a top surface of both the first and second conductive adhesive layers; and   a conformal metal shield over the over-mold and over the first and second conductive adhesive layers, the first conductive adhesive layer and the conformal metal shield forming a path from the first semiconductor die to a ground reference and the second conductive adhesive layer and the conformal metal shield forming a path from the second semiconductor die to the ground reference.   
     
     
         10 . The radio frequency packaged module of  claim 9  wherein each of the semiconductor dies include one or more of a surface acoustic wave filter, bulk acoustic wave filter, power amplifier, or a low-noise amplifier. 
     
     
         11 . The radio frequency packaged module of  claim 9  wherein the radio frequency packaged module is a front-end module. 
     
     
         12 . The radio frequency packaged module of  claim 9  wherein the conformal metal shield is configured to substantially attenuate radio frequency signals causing electromagnetic interference in the n77, n78, or n79 New Radio frequency bands. 
     
     
         13 . The radio frequency packaged module of  claim 9  wherein the radio frequency packaged module is configured as a ball grid array package. 
     
     
         14 . The radio frequency packaged module of  claim 9  further comprising a plurality of bond wires forming a wire cage around the radio frequency packaged module. 
     
     
         15 . A mobile device comprising the radio frequency packaged module of  claim 9 , the mobile device further comprising an antenna coupled to the radio frequency packaged module. 
     
     
         16 . The mobile device of  claim 15  further comprising a plurality of bond wires extending between the printed circuit board and conformal metal shield to form a wire cage around the radio frequency packaged module. 
     
     
         17 . The mobile device of  claim 16  wherein the wire cage is configured to attenuate radio frequency noise emissions of the first and second semiconductor dies by coupling the noise emissions to the ground reference. 
     
     
         18 . The mobile device of  claim 16  wherein the plurality of bond wires form a perimeter boundary around the first and second semiconductor dies. 
     
     
         19 . The mobile device of  claim 16  wherein the first and second conductive adhesive layers each form an electrical connection between one or more of the bond wires and the ground reference. 
     
     
         20 . A mobile device comprising:
 a shielded integrated circuit package including a printed circuit board, a semiconductor die mounted to the printed circuit board and having a conductive top surface, a conductive adhesive layer provided on the conductive top surface, an over-mold above the printed circuit board, the over-mold encasing a periphery of the semiconductor die while exposing at least a portion of a top surface of the conductive adhesive layer, and a conformal metal shield over the over-mold and over the conductive adhesive layer, the conductive adhesive layer and the conformal metal shield forming a path from the semiconductor die to a ground reference; and   an antenna coupled to the shielded integrated circuit package.