Integrated circuit devices having improved contact plug structures therein

An integrated circuit device comprising:

• a first interlayer insulating layer on a substrate;
• an electrically conductive line on the first interlayer insulating layer;
• a second interlayer insulating layer, which extends on the first interlayer insulating layer and opposite a sidewall of the line;
• an electrically conductive contact plug, which at least partially penetrates the first interlayer insulating layer and is electrically connected to a portion of the line, said contact plug comprising a protrusion that extends into a space between:
• (i) the line, which overlaps a first portion of the protrusion, and (ii) the second interlayer insulating layer, which overlaps a second portion of the protrusion;
• a line barrier pattern extending between the sidewall of the line and the second interlayer insulating layer;
• and wherein the line barrier pattern extends on a top surface of the protrusion;
• and
• an etch stop layer extending between the second interlayer insulating layer and the first interlayer insulating layer, and extending between the second interlayer insulating layer and the protrusion;
• and
• wherein the line barrier pattern extends between the line and a portion of the etch stop layer.

An integrated circuit device, comprising:

• a substrate;
• a first electrically insulating layer on the substrate;
• an electrically conductive contact plug extending at least partially through the first electrically insulating layer, said contact plug comprising a protrusion having a top surface that is spaced farther from the substrate relative to a top surface of a portion of the first electrically insulating layer extending adjacent the contact plug;
• an electrically conductive line having a terminal end, which extends on a first portion of the protrusion;
• and
• a second electrically insulating layer extending on a second portion of the protrusion and on the first electrically insulating layer, said second electrically insulating layer having a sidewall extending opposite a sidewall of the terminal end of the electrically conductive line.