Abstract: A multilayer resin substrate includes a stacked body including resin layers stacked on each other, a first planar conductor on a resin layer, and an interlayer connection conductor on a resin layer. The interlayer connection conductor includes a first interlayer connection conductor connected to an external conductor, and a second interlayer connection conductor bonded to the first interlayer connection conductor and a planar conductor. The first and second interlayer connection conductors are made of different materials. The second interlayer connection conductor includes a constricted portion including a smaller planar cross-sectional area than a different portion, between a bonding portion to which the first interlayer connection conductor is bonded and a bonding portion to which the planar conductor is bonded.

Abstract: A multilayer resin substrate includes a stacked body including resin layers stacked on each other, a first planar conductor on a resin layer, and an interlayer connection conductor on a resin layer. The interlayer connection conductor includes a first interlayer connection conductor connected to an external conductor, and a second interlayer connection conductor bonded to the first interlayer connection conductor and a planar conductor. The first and second interlayer connection conductors are made of different materials. The second interlayer connection conductor includes a constricted portion including a smaller planar cross-sectional area than a different portion, between a bonding portion to which the first interlayer connection conductor is bonded and a bonding portion to which the planar conductor is bonded.

Abstract: A multilayer wiring board includes first and second insulating layers, a first conductive wiring layer on the first insulating layer, a second conductive wiring layer on a surface of the second insulating layer facing the first insulating layer, an interlayer connection conductor including an intermetallic compound and penetrating through the first insulating layer to interconnect the first and second conductive wiring layers, a first intermetallic compound layer between the first conductive wiring layer and the interlayer connection conductor, and a second intermetallic compound layer between the second conductive wiring layer and the interlayer connection conductor, wherein the intermetallic compounds in the first and second intermetallic compound layers have a composition different from that of the intermetallic compound in the interlayer connection conductor, and the first intermetallic compound layer is located at a level different from a level of an interface between the first conductive wiring layer an

Abstract: A multilayer wiring board includes first and second insulating layers, a first conductive wiring layer on the first insulating layer, a second conductive wiring layer on a surface the second insulating layer facing the first insulating layer, an interlayer connection conductor including an intermetallic compound and penetrating through the first insulating layer to interconnect the first and second conductive wiring layers, a first intermetallic compound layer between the first conductive wiring layer and the interlayer connection conductor, and a second intermetallic compound layer between the second conductive wiring layer and the interlayer connection conductor, wherein the intermetallic compounds in the first and second intermetallic compound layers have a composition different from that of the intermetallic compound in the interlayer connection conductor, and the first intermetallic compound layer at a level different from a level of an interface between the first conductive wiring layer and the first in