A wiring board includes: an insulating layer; and a connection terminal formed on the insulating layer. The connection terminal includes a first metal layer laminated on the insulating layer, a second metal layer laminated on the first metal layer, a metal pad laminated on the second metal layer, and a surface treatment layer that covers an upper surface and a side surface of the pad and that is in contact with the upper surface of the insulating layer. An end portion of the second metal layer is in contact with the surface treatment layer, and an end portion of the first metal layer is positioned closer to a center side of the pad than the end portion of the second metal layer is to form a gap between the end portion of the first metal layer and the surface treatment layer.

A wiring board includes: an insulating layer; and a connection terminal formed on the insulating layer. The connection terminal includes a first metal layer laminated on the insulating layer, a second metal layer laminated on the first metal layer, a metal pad laminated on the second metal layer, and a surface treatment layer that covers an upper surface and a side surface of the pad and that is in contact with the upper surface of the insulating layer. An end portion of the second metal layer is in contact with the surface treatment layer, and an end portion of the first metal layer is positioned closer to a center side of the pad than the end portion of the second metal layer is to form a gap between the end portion of the first metal layer and the surface treatment layer.

A method for fabricating a semiconductor device with a heterogeneous solder joint includes: providing a semiconductor die; providing a coupled element; and soldering the semiconductor die to the coupled element with a first solder joint. The first solder joint includes: a solder material including a first metal composition; and a coating including a second metal composition, different from the first metal composition, the coating at least partially covering the solder material. The second metal composition has a greater stiffness and/or a higher melting point than the first metal composition.

A method for fabricating a semiconductor device with a heterogeneous solder joint includes: providing a semiconductor die; providing a coupled element; and soldering the semiconductor die to the coupled element with a first solder joint. The first solder joint includes: a solder material including a first metal composition; and a coating including a second metal composition, different from the first metal composition, the coating at least partially covering the solder material. The second metal composition has a greater stiffness and/or a higher melting point than the first metal composition.

A wiring board includes: an insulating layer; and a connection terminal formed on the insulating layer. The connection terminal includes a first metal layer laminated on the insulating layer, a second metal layer laminated on the first metal layer, a metal pad laminated on the second metal layer, and a surface treatment layer that covers an upper surface and a side surface of the pad and that is in contact with the upper surface of the insulating layer. An end portion of the second metal layer is in contact with the surface treatment layer, and an end portion of the first metal layer is positioned closer to a center side of the pad than the end portion of the second metal layer is to form a gap between the end portion of the first metal layer and the surface treatment layer.

A wiring board includes: an insulating layer; and a connection terminal formed on the insulating layer. The connection terminal includes a first metal layer laminated on the insulating layer, a second metal layer laminated on the first metal layer, a metal pad laminated on the second metal layer, and a surface treatment layer that covers an upper surface and a side surface of the pad and that is in contact with the upper surface of the insulating layer. An end portion of the second metal layer is in contact with the surface treatment layer, and an end portion of the first metal layer is positioned closer to a center side of the pad than the end portion of the second metal layer is to form a gap between the end portion of the first metal layer and the surface treatment layer.

A bump electrode is formed on an electrode pad using a Cu core ball in which a core material is covered with solder plating, and a board which has bump electrodes such as semiconductor chip or printed circuit board mounts such a bump electrode. Flux is coated on a substrate and the bump electrodes are then mounted on the electrode pad. In a step of heating the electrode pad and the Cu core ball to melt the solder plating, a heating rate of the substrate is set to have not less than 0.01 C./sec and less than 0.3.

A bump electrode is formed on an electrode pad using a Cu core ball in which a core material is covered with solder plating, and a board which has bump electrodes such as semiconductor chip or printed circuit board mounts such a bump electrode. Flux is coated on a substrate and the bump electrodes are then mounted on the electrode pad. In a step of heating the electrode pad and the Cu core ball to melt the solder plating, a heating rate of the substrate is set to have not less than 0.01 C./sec and less than 0.3.