A semiconductor device includes: a wiring board including a first electrode pad on a surface thereof; a circuit board disposed to stand on the wiring board, and including an interconnection connected to the first electrode pad; and a semiconductor package disposed to face the wiring board with the circuit board interposed therebetween, and including a second electrode pad on a surface thereof, the second electrode pad being connected to the interconnection.

A semiconductor device includes: a wiring board including a first electrode pad on a surface thereof; a circuit board disposed to stand on the wiring board, and including an interconnection connected to the first electrode pad; and a semiconductor package disposed to face the wiring board with the circuit board interposed therebetween, and including a second electrode pad on a surface thereof, the second electrode pad being connected to the interconnection.

Provided is a flux agent according to embodiments of the inventive concept, wherein the flux agent includes a first compound including an ester group and an epoxy group, a fourth compound which is a chemical reactant of a second compound including an epoxy group and a third compound including an amine group and a carboxyl group, and a photoinitiator, wherein the content of the first compound is 50 wt % to 60 wt % based on 95 wt % of the total agent, the content of the fourth compound is 3 wt % to 33 wt % based on 100 wt % of the total agent, and the content of the photoinitiator is 2 wt % to 10 wt % based on 100 wt % of the total agent.