Abstract: An electronic component mounting substrate includes: an insulating substrate having a recess that opens in a main surface of the insulating substrate, the recess for mounting an electronic component; a metal layer located on a bottom surface of the recess; an external electrode located on the other main surface of the insulating substrate, the other main surface opposite to the main surface; a connection wiring located between the metal layer and the external electrode in a thickness direction of the insulating substrate; a plurality of first vias that connects the metal layer and the connection wiring and that is located along a side wall of the recess in a perspective plan view; and a plurality of second vias that connects the connection wiring and the external electrode and that is located in a strip shape in the perspective plan view.

Abstract: An electronic component mounting substrate including: an insulating substrate for mounting an electronic component; a via conductor disposed in the insulating substrate in an thickness direction of the insulating substrate; and a via pad conductor disposed in the insulating substrate, connected to the via conductor, having a thickness gradually increasing from an outer edge portion toward an inside portion, and including a protruding portion protruding from the via conductor in a width direction of the via conductor.

Abstract: An electronic component mounting substrate including: an insulating substrate for mounting an electronic component; a via conductor disposed in the insulating substrate in an thickness direction of the insulating substrate; and a via pad conductor disposed in the insulating substrate, connected to the via conductor, having a thickness gradually increasing from an outer edge portion toward an inside portion, and including a protruding portion protruding from the via conductor in a width direction of the via conductor.

Abstract: An electronic component mounting substrate includes: an insulating substrate having a recess that opens in a main surface of the insulating substrate, the recess for mounting an electronic component; a metal layer located on a bottom surface of the recess; an external electrode located on the other main surface of the insulating substrate, the other main surface opposite to the main surface; a connection wiring located between the metal layer and the external electrode in a thickness direction of the insulating substrate; a plurality of first vias that connects the metal layer and the connection wiring and that is located along a side wall of the recess in a perspective plan view; and a plurality of second vias that connects the connection wiring and the external electrode and that is located in a strip shape in the perspective plan view.