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. An electronic device comprising:
a semiconductor chip having an area;
ferromagnetic material with a body including a flat area;
the chip attached to the flat body area;
a bonder wire having a first and a second end, the bonder wire wrapped around the body to form at least a portion of a loop;
the first and second bonder wire ends connected to the chip; and
the chip, the body and the bonder wire encapsulated in an insulating compound.
2. The device according to claim 1 wherein the chip includes one or more circuit chips or discrete components.
3. An electronic device comprising:
a semiconductor chip having an area, an active surface including a first and a second set of terminals, and a passive surface;
a substrate having contact pads;
the passive chip surface attached to the substrate;
a body containing ferromagnetic material including a flat area smaller than the chip area;
the flat body area attached to the active chip surface;
a bonder wire having a first and a second end, the bonder wire wrapped around the body to form at least a portion of a loop;
the first and second bonder wire ends connected to the first set terminals;
the second set terminals connected to the contact pads; and
insulating compound encapsulating the assembled chip, ferromagnetic body and electrical connections.
4. The device according to claim 3 further including a thermally conductive attach material between the body and the chip.
5. The device according to claim 3 further having an insulation between the looping bonder wire and the body.
6. The device according to claim 5 wherein the insulation is provided by separators creating a distance between the looping bonder wire and the surface of the body.
7. The device according to claim 3 wherein the connections of the bonder wire ends to the first set terminals are wire bonds.
8. The device according to claim 3 wherein the connections of the second set terminals to the contact pads are wire bonds.
9. The device according to claim 3 wherein the connections of the second set terminals to the contact pads are metal studs.
10. The device according to claim 3 wherein the substrate is a metallic leadframe.
11. The device according to claim 3 wherein the flat area of the ferromagnetic body is formed by a plate extending beyond the body periphery, the extension providing connection sites for the first and second bonder wire ends as well as conductive attachment of the body to the first set chip terminals.
12. The device according to claim 11 wherein the plate is made of ferromagnetic material so that the plate is operable to shield the magnetic field from interfering with the chip.
13. An electronic device comprising:
a semiconductor chip having an active surface including a first and a second set of terminals, and a passive surface;
a substrate having contact pads;
a body containing ferromagnetic material including a first and a second flat portion, a flat portion having connection ports;
the passive chip surface attached to the first flat portion of the body;
the first set terminals connected to the ports;
a bonder wire having a first and a second end, the bonder wire wrapped around the body to form at least a portion of a loop;
the first and second bonder wire ends connected to the first set terminals;
the second flat portion of the body attached to the substrate; and
the second set terminals connected to the contact pads.
14. The device according to claim 13 further having passive units assembled with the chip or the body.
15. The device according to claim 13 further including an encapsulation of the assembled chip, ferromagnetic body and electrical connections in an insulating compound.
16. The device according to claim 13 wherein the substrate is a metallic leadframe.
17. The device according to claim 13 wherein the first and the second flat portion of the body containing ferromagnetic material is formed by a plate extending beyond the body periphery, the extension providing connection sites for the first and second bonder wire ends as well as conductive attachment of the body to the first set chip terminals.
18. The device according to claim 17 wherein the plates are made of ferromagnetic material so that the plates are operable to shield the magnetic field from interfering with the chip.