Methods of manufacturing three-dimensional semiconductor devices and related devices

A method of forming a three-dimensional semiconductor device, the method comprising:

• forming a thin film structure on wiring and contact regions of a substrate, wherein the thin film structure includes a plurality of alternating sacrificial layers and inter-layer insulating layers, and wherein the thin film structure defines a terraced structure in the contact region;
• forming an insulating layer on the terraced structure in the contact region;
• forming sacrificial contact patterns through the insulating layer in the contact region in a direction perpendicular with respect to a surface of the substrate, wherein each of the sacrificial contact patterns is connected to a respective one of the sacrificial layers;
• removing the sacrificial layers and the sacrificial contact patterns to define recess regions between the inter-layer insulating layers and through the insulating layer;
• and
• forming wiring patterns in the recess regions between the inter-layer insulating layers and through the insulating layer.