A semiconductor device and methods of forming the same are provided. The methods may include forming a hole in a preliminary semiconductor substrate, forming an insulating layer in the hole of the preliminary semiconductor substrate, forming a plating conductive layer on the insulating layer and the preliminary semiconductor substrate, forming a seed metal layer contacting the plating conductive layer at a lower portion of the hole and growing the seed metal layer to form a through-silicon via (TSV). The TSV may be formed through an electroplating process such that the seed metal layer grows from the lower portion of the hole to an upper portion of the hole.