Semiconductor devices and data storage systems including the same

A method of manufacturing a semiconductor device, comprising:

• forming a first substrate structure;
• forming a second substrate structure;
• and
• bonding the first substrate structure and the second substrate structure,
• wherein the forming the first substrate structure includes:
• forming a stack structure by alternately stacking sacrificial insulating layers and interlayer insulating layers on a plate layer,
• forming a channel structure passing through the stack structure,
• removing the sacrificial insulating layers to form tunnel portions,
• forming gate electrodes by filling the tunnel portions with a conductive material, and
• forming a first interconnection structure and a first bonding structure on the gate electrodes, and
• wherein the forming the second substrate structure includes:
• forming first device isolation layers having a first height and a second device isolation layer having a second height, greater than the first height, in a substrate to define first active regions and second active regions,
• forming circuit devices, a second interconnection structure, and a second bonding structure on the substrate,
• partially removing the substrate to expose the second device isolation layer, and
• forming a third interconnection structure on an exposed surface of the second device isolation layer.

A method of manufacturing a semiconductor device, comprising:

• forming first device isolation layers having a first height in a substrate to define first active regions and second active regions;
• forming a second device isolation layer having a second height, greater than the first height, between the first active regions and the second active regions in the substrate;
• forming circuit devices and a lower interconnection structure on a first surface of the substrate;
• attaching a carrier substrate on the lower interconnection structure;
• partially removing the substrate from a second surface of the substrate to separate the first active regions and the second active regions;
• and
• forming an upper interconnection structure on the second surface of the substrate.

A method of manufacturing a semiconductor device, comprising:

• forming a first substrate structure including memory cells arranged three-dimensionally;
• forming a second substrate structure;
• and
• bonding the first substrate structure and the second substrate structure,
• wherein the forming the second substrate structure includes:
• forming first device isolation layers and a second device isolation layer having different heights in a substrate,
• forming circuit devices and a lower interconnection structure on a first surface of the substrate,
• partially removing the substrate from a second surface of the substrate such that the substrate is completely removed on the second device isolation layer, and
• forming an upper interconnection structure on the second surface of the substrate.