An interposer including a base layer, a redistribution structure on a first surface of the base layer and including a conductive redistribution pattern, a first lower protection layer on a second surface of the base layer, a lower conductive pad on the first lower protection layer, a through electrode connecting the conductive redistribution pattern and the lower conductive pad, a second lower protection layer on the first lower protection layer, including a different material than the first lower protection layer, and contacting at least a portion of the lower conductive pad, and an indentation formed in an outer edge region of the interposer to provide a continuous angled sidewall extending entirely through the second lower protection layer and through at least a portion of the first protection layer.