Gates of a plurality of semiconductor switching elements are electrically connected to a common gate control pattern by gate wires. Sources of the plurality of semiconductor switching elements are electrically connected to a common source control pattern by source wires. The gate control pattern is disposed to interpose the source control pattern between the gate control pattern and each of the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel. Hence, each of the gate wires becomes longer than each of the source wires, and has an inductance larger than the source wire. Accordingly, gate oscillation is reduced or suppressed in the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel.

Gates of a plurality of semiconductor switching elements are electrically connected to a common gate control pattern by gate wires. Sources of the plurality of semiconductor switching elements are electrically connected to a common source control pattern by source wires. The gate control pattern is disposed to interpose the source control pattern between the gate control pattern and each of the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel. Hence, each of the gate wires becomes longer than each of the source wires, and has an inductance larger than the source wire. Accordingly, gate oscillation is reduced or suppressed in the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel.

Gates of a plurality of semiconductor switching elements are electrically connected to a common gate control pattern by gate wires. Sources of the plurality of semiconductor switching elements are electrically connected to a common source control pattern by source wires. The gate control pattern is disposed to interpose the source control pattern between the gate control pattern and each of the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel. Hence, each of the gate wires becomes longer than each of the source wires, and has an inductance larger than the source wire. Accordingly, gate oscillation is reduced or suppressed in the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel.

Gates of a plurality of semiconductor switching elements are electrically connected to a common gate control pattern by gate wires. Sources of the plurality of semiconductor switching elements are electrically connected to a common source control pattern by source wires. The gate control pattern is disposed to interpose the source control pattern between the gate control pattern and each of the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel. Hence, each of the gate wires becomes longer than each of the source wires, and has an inductance larger than the source wire. Accordingly, gate oscillation is reduced or suppressed in the plurality of semiconductor switching elements that are connected in parallel and that operate in parallel.

A micro-coaxial wire has an overall diameter in a range of 0.1 m-550 m, a conductive core of the wire has a cross-sectional diameter in a range of 0.05 m-304 m, an insulator is disposed on the conductive core with thickness in a range of 0.005 m-180 m, and a conductive shield layer is disposed on the insulator with thickness in a range of 0.009 m-99 m.

A micro-coaxial wire has an overall diameter in a range of 0.1 m-550 m, a conductive core of the wire has a cross-sectional diameter in a range of 0.05 m-304 m, an insulator is disposed on the conductive core with thickness in a range of 0.005 m-180 m, and a conductive shield layer is disposed on the insulator with thickness in a range of 0.009 m-99 m.

Performance of a semiconductor device is improved. Graphene particles are mixedly added in a sealing resin covering a semiconductor chip. The graphene particles are thus mixedly added in the sealing resin, thereby thermal conduction of the sealing resin is improved, and thus radiation performance of the semiconductor device can be improved. Graphene is a sheet of sp.sup.2 bonded carbon atoms having a monolayer thickness. Graphene has a structure where hexagonal lattices, each of which is formed of carbon atoms and bonds of the carbon atoms, are planarly spread. Graphene is preferably used as heat transfer filler because of its high thermal conductivity and light weight.

Reliability of a semiconductor device is improved. A wire bonding step includes a step of exposing a wire and a pad electrode to a reducing gas atmosphere, forming a first hydroxyl layer on a surface of a ball portion, and forming a second hydroxyl layer on a surface of the pad electrode, a first bonding step of temporarily joining the ball portion to the pad electrode through the first hydroxyl layer and the second hydroxyl layer, and after the first bonding step, a step of actually joining the ball portion to the pad electrode by performing a heat treatment on a semiconductor chip and a base material.

Reliability of a semiconductor device is improved.

A wire bonding step includes a step of exposing a wire and a pad electrode to a reducing gas atmosphere, forming a first hydroxyl layer on a surface of a ball portion, and forming a second hydroxyl layer on a surface of the pad electrode, a first bonding step of temporarily joining the ball portion to the pad electrode through the first hydroxyl layer and the second hydroxyl layer, and after the first bonding step, a step of actually joining the ball portion to the pad electrode by performing a heat treatment on a semiconductor chip and a base material.

Performance of a semiconductor device is improved. Graphene particles are mixedly added in a sealing resin covering a semiconductor chip. The graphene particles are thus mixedly added in the sealing resin, thereby thermal conduction of the sealing resin is improved, and thus radiation performance of the semiconductor device can be improved. Graphene is a sheet of sp.sup.2 bonded carbon atoms having a monolayer thickness. Graphene has a structure where hexagonal lattices, each of which is formed of carbon atoms and bonds of the carbon atoms, are planarly spread. Graphene is preferably used as heat transfer filler because of its high thermal conductivity and light weight.