A method of fabricating a semiconductor package including forming a preliminary first insulating layer including a first opening, curing the preliminary first insulating layer to form a first insulating layer, forming a preliminary second insulating layer on the first insulating layer at least partially filling the first opening. The method includes forming a second opening in the preliminary second insulating layer at least partially overlapping the first opening. A sidewall of the first opening is at least partially exposed during forming the second opening. The preliminary second insulating layer is cured to form a second insulating layer. A barrier metal layer is formed along the sidewall of the first opening and along a sidewall of the second opening. A redistribution conductive pattern is formed on the barrier metal layer. A planarization process is performed to at least partially expose the second insulating layer.