Methods of manufacturing vertical memory devices

A method of manufacturing a vertical memory device, the method comprising:

• forming a preliminary mold structure on a substrate, the substrate including a main region and an edge region, and the preliminary mold structure including insulation layers and sacrificial layers alternately and repeatedly stacked;
• forming a first mask on the preliminary mold structure on the main region of the substrate, the first mask serving as a mask for forming a step structure of the preliminary mold structure;
• forming a second mask on the preliminary mold structure on the edge region of the substrate, the second mask exposing an upper surface of the preliminary mold structure on a first region between a boundary of the substrate and a first target position;
• partially etching the insulation layers and the sacrificial layers using the first and second masks as an etching mask to form a first preliminary mold structure on the main region of the substrate and a second preliminary mold structure on the edge region of the substrate;
• forming a third mask on the preliminary first mold structure, the third mask serving as a mask for forming a step structure of the preliminary first mold structure;
• forming a fourth mask on the preliminary second mold structure, the fourth mask exposing an upper surface of the preliminary second mold structure on a region between the boundary of the substrate and a second target position, wherein the second target position is different from the first target position;
• and
• partially etching the insulation layers and the sacrificial layers using the third and fourth masks as an etching mask to form a second mold structure on the main region of the substrate and a first mold structure on the edge region of the substrate,
• wherein a sidewall of the second mold structure includes a first step structure, and a sidewall of the first mold structure includes a second step structure different from the first step structure.

A method of manufacturing a vertical memory device, the method comprising:

• forming a preliminary first mold structure on a substrate, the substrate including a main region and an edge region, and the first preliminary mold structure including insulation layers and sacrificial layers alternately and repeatedly stacked;
• forming a first mask on the preliminary first mold structure, the first mask exposing an upper surface of the preliminary first mold structure in a region between a boundary of the substrate and a first target position;
• partially etching the insulation layers and the sacrificial layers using the first mask as an etching mask to form a preliminary second mold structure including a preliminary step structure;
• forming a second mask on the preliminary second mold structure, the second mask exposing an upper surface of the preliminary second mold structure in a region between the boundary of the substrate and a second target position, wherein the second target position is farther from the boundary of the substrate than the first target position;
• and
• partially etching the insulation layers and the sacrificial layers using the second mask as an etching mask to form a mold structure on the main region and the edge region of the substrate.