A semiconductor structure includes a substrate; a pad disposed over the substrate; a first passivation disposed over the substrate, partially covering the pad, and including a protrusion protruded from the first passivation and away from the substrate; a conductive layer disposed over the first passivation and a portion of the pad exposed from the first passivation; and a second passivation disposed over the conductive layer, wherein the conductive layer disposed over the protrusion is exposed from the second passivation.