Disclosed is a semiconductor device comprising a semiconductor substrate, a conductive pad on a first surface of the semiconductor substrate, a passivation layer on the first surface of the semiconductor substrate, the passivation layer having a first opening that exposes the conductive pad, an organic dielectric layer on the passivation layer, the organic dielectric layer having a second opening, and a bump structure on the conductive pad and in the first and second openings. The organic dielectric layer includes a material different from a material of the passivation layer. The second opening is spatially connected to the first opening and exposes a portion of the passivation layer. The bump structure includes a pillar pattern in contact with the passivation layer and the organic dielectric layer.