Method of manufacturing a semiconductor device including isolation structures

A method of manufacturing a semiconductor device, comprising:

• forming active regions on a substrate, the active regions extending in a first direction and spaced apart from each other in a second direction;
• forming a plurality of sacrificial gate structures extending in the second direction and intersecting the active regions on the substrate, the each of the plurality of sacrificial gate structures;
• forming source/drain regions on the active regions on at least one side of the plurality of sacrificial gate structures;
• removing the plurality of sacrificial gate to form gap regions;
• forming a plurality of gate structures in the gap regions, each of the plurality of gate structures extending in the second direction and intersecting the active regions on the substrate;
• forming a first opening penetrating through the plurality of gate structures and extending in the first direction;
• forming a first isolation structure in the first opening to isolate the plurality of gate structures from each other in the second direction;
• forming second openings penetrating through the first isolation structure and spaced apart from each other in the first direction;
• forming second isolation structures in the second openings;
• and
• forming a common contact plug extending in the second direction and disposed between the plurality of gate structures,
• wherein the common contact plug includes a first portion between the plurality of gate structures and a second portion between the second isolation structures, and
• a width of the second portion in the first direction is different from a width of the first portion in the first direction.

A method of manufacturing a semiconductor device, comprising:

• forming active regions on a substrate, the active regions extending in a first direction and spaced apart from each other in a second direction;
• forming a plurality of sacrificial gate structures extending in the second direction and intersecting the active regions on the substrate, the each of the plurality of sacrificial gate structures;
• forming source/drain regions on the active regions on at least one side of the plurality of sacrificial gate structures;
• forming an insulating liner on the source/drain regions, and the plurality of sacrificial gate structures;
• forming an interlayer insulating layer on the insulating liner;
• removing the plurality of sacrificial gate to form gap regions;
• forming a plurality of gate structures in the gap regions, each of the plurality of gate structures extending in the second direction and intersecting the active regions on the substrate;
• forming a first mask layer on the plurality of gate structures and the interlayer insulating layer;
• forming a second mask layer on the first mask layer;
• forming a first opening of a line type that penetrates through the plurality of gate structures, the first mask layer, and the second mask layer, the first opening extending in the first direction;
• forming a first isolation structure in the first opening and removing the second mask layer;
• forming second openings of a hole type that penetrates through the first isolation structure and spaced apart from each other in the first direction;
• forming second isolation structures in the second openings and removing the first mask layer;
• and
• forming a common contact plug extending in the second direction and disposed between the plurality of gate structures,
• wherein the common contact plug includes a first portion between the plurality of gate structures and a second portion between the second isolation structures, and
• wherein the second portion has an outwardly curved shape that is curved toward the second isolation structures.