Power semiconductor devices having integrated inductor
An electronic device ( 100 ) with one or more semiconductor chips ( 102 ) has an inductor ( 101 ) assembled on or under the chips. The inductor includes a ferromagnetic body ( 111 ) and a wire ( 104 ) wrapped around the body to form at least a portion of a loop; the wire ends ( 104 a ) are connected to the chips. The assembly is attached to a substrate ( 103 ), which may be a leadframe. The device may be encapsulated in molding compound ( 140 ) so that the inductor can double as a heat spreader ( 111 c ), enhancing the thermal device characteristics.
1. A method for fabricating an electronic device comprising the steps of:
providing a semiconductor chip having an area, an active surface including a first and a second set of terminals, and a passive surface;
providing a substrate having contact pads;
attaching the passive chip surface to the substrate;
providing a body containing ferromagnetic material including a flat area smaller than the chip area;
attaching the flat body area to the active chip surface;
providing a bonder wire having a first and a second end;
wrapping the bonder wire around the body by means of a semiconductor wire bonder to form at least a portion of a loop;
connecting the first and second bonder wire ends to the first set terminals;
connecting the second set terminals to the contact pads; and
encapsulating the assembled chip, ferromagnetic body and electrical connections in an insulating compound.
2. A method for fabricating an electronic device comprising the steps of:
providing a semiconductor chip having an active surface including a first and a second set of terminals, and a passive surface;
providing a substrate having contact pads;
providing a body containing ferromagnetic material including a first and a second flat portion, a flat portion having connection ports;
attaching the passive chip surface to the first flat portion of the body;
providing a bonder wire having a first and a second end;
wrapping the wire around the body by means of a semiconductor wire bonder to form at least a portion of a loop;
connecting the first and second bonder wire ends to the first set terminals;
attaching the second flat portion of the body to the substrate;
connecting the first set terminals to the ports;
connecting the second set terminals to the contact pads; and
encapsulating the assembled chip, ferromagnetic body, and electrical connections in an insulating compound.
3. A method for fabricating an electronic device comprising the steps of:
attaching a first surface of a semiconductor chip to a first flat portion of a body containing ferromagnetic material;
wire-bonding a first bonder wire by means of a first semiconductor wire bonder to a first bond pad on the semiconductor chip;
wrapping a second bonder wire by means of a second semiconductor wire bonder around the body to form at least a portion of a loop; and
terminating a first end and a second end of the second bonder wire between a second bond pad and a third bond pad.
4. The method of claim 3 , in which the first bond pad, the second bond pad and the third bond pad are on the first surface of the semiconductor chip.
5. The method of claim 3 , further comprising attaching a second surface of the semiconductor chip opposite the first surface to a substrate.
6. The method of claim 3 , in which an end of the first bonder wire is bonded to a fourth bond pad on the substrate.
7. The method of claim 3 , in which the at least a portion of a loop includes multiple loops.
8. The method of claim 5 , in which the second bond pad and the third bond pad are on the substrate.
9. The method of claim 5 , in which the second bond pad and the third bond pad are on a second substrate.
10. The method of claim 5 , in which the substrate is a leadframe.
11. The method of claim 3 , in which the first and the second semiconductor wire bonder are the same wire bonder.
12. The method of claim 6 , in which the second and the third bond pad are on opposite sides of the substrate.