Power stage package including flexible circuit and stacked die

Abstract

A semiconductor package includes a substrate, a set of terminals protruding from a first surface of the substrate, a power stage physically and thermally coupled to the first surface of the substrate, and a flexible circuit including at least one circuit layer forming power stage conductors and control circuit conductors disposed on a flexible insulating substrate layer. The power stage is between the flexible circuit and the substrate and is mounted on a first surface of the flexible circuit such that the power stage is electrically connected to the power stage conductors. The package includes a die mounted on a second surface of the flexible circuit opposite the power stage. An output of the die is electrically connected to an input of the power stage via the control circuit conductors.

What is claimed is: 
     
         1 . A semiconductor package comprising:
 a substrate forming a first surface and a second surface that opposes the first surface;   a set of terminals of the semiconductor package attached to the first surface of the substrate via a conductive adhesive and protruding from the first surface of the substrate;   a gallium nitride die attached to the first surface of the substrate;   a flexible circuit on the gallium nitride die, the flexible circuit including at least one circuit layer disposed on a flexible insulating substrate layer;   a control die on a second surface of the flexible circuit opposite the gallium nitride die; and   mold compound covering portions of the substrate, the set of terminals, the gallium nitride die, the flexible circuit.   
     
     
         2 . The semiconductor package of  claim 1 , further comprising one or more passive components of a sensing circuit mounted on the second surface of the flexible circuit and electrically connected to the control die. 
     
     
         3 . The semiconductor package of  claim 1 , wherein the flexible circuit includes alignment features engaged with the set of terminals protruding from the substrate. 
     
     
         4 . The semiconductor package of  claim 1 , wherein the set of terminals protruding through the flexible circuit and the mold compound to an external portion of the semiconductor package. 
     
     
         5 . The semiconductor package of  claim 1 , wherein the flexible circuit includes a bend radius under 25 millimeters. 
     
     
         6 . The semiconductor package of  claim 1 , wherein the substrate is a direct bonded copper substrate including a ceramic base and a copper layer on the ceramic base, the gallium nitride die attached to the copper layer. 
     
     
         7 . The semiconductor package of  claim 1 , further comprising a thermal interface material between the gallium nitride die and the first surface of the substrate. 
     
     
         8 . The semiconductor package of  claim 1 , further comprising:
 a first set of solder bumps forming electrical connections between the gallium nitride die and the flexible circuit such that the gallium nitride die is mounted on the first surface of the flexible circuit in a first flipchip arrangement.   
     
     
         9 . The semiconductor package of  claim 1 , further comprising a heat sink physically and thermally coupled to a second surface of the substrate, the second surface of the substrate opposing the first surface of the substrate. 
     
     
         10 . A semiconductor package comprising:
 a substrate forming a first surface and a second surface that opposes the first surface;   a set of terminals of the semiconductor package attached to the first surface of the substrate via a conductive adhesive and protruding from the first surface of the substrate;   a first gallium nitride die and a second gallium nitride die attached to the first surface of the substrate;   a flexible circuit on the first gallium nitride die and the second gallium nitride die, the flexible circuit including at least one circuit layer disposed on a flexible insulating substrate layer, wherein a top surface of the flexible circuit includes two sections at different planes in a cross-sectional view of the semiconductor package; and   a control die on a second surface of the flexible circuit opposite the gallium nitride die; and   mold compound covering portions of the substrate, the set of terminals, the gallium nitride die, the flexible circuit.   
     
     
         11 . The semiconductor package of  claim 10 , further comprising one or more passive components of a sensing circuit mounted on the second surface of the flexible circuit and electrically connected to the control die. 
     
     
         12 . The semiconductor package of  claim 10 , wherein the flexible circuit includes alignment features engaged with the set of terminals protruding from the substrate. 
     
     
         13 . The semiconductor package of  claim 10 , wherein the set of terminals protruding through the flexible circuit and the mold compound to an external portion of the semiconductor package. 
     
     
         14 . The semiconductor package of  claim 10 , further comprising a heat sink physically and thermally coupled to a second surface of the substrate, the second surface of the substrate opposing the first surface of the substrate. 
     
     
         15 . The semiconductor package of  claim 10 , wherein the substrate is a direct bonded copper substrate including a ceramic base and a copper layer on the ceramic base, the first gallium nitride die and the second gallium nitride die attached to the copper layer.