Semiconductor device having a dam structure

Abstract

A semiconductor device includes a memory stack on a substrate, the memory stack including gate electrodes, insulating layers and mold layers, the mold layers being disposed at the same levels as the gate electrodes in a through electrode area, a channel structure extending vertically through the gate electrodes in a cell array area, and a dam structure disposed between the isolation insulating layers and surrounding the through electrode area in a top view. The dam structure includes a dam insulating layer having a dam shape, an inner insulating layer inside the dam insulating layer, and an outer insulating layer outside the dam insulating layer. The inner insulating layer includes first protrusions protruding in a horizontal direction, and the outer insulating layer includes second protrusions protruding in the horizontal direction.