Flash memory device and method of fabricating the same
Disclosed here in is a flash memory device and a method of fabricating the same. In accordance with one aspect of the invention, a flash memory device includes first contact plugs formed over a semiconductor substrate between gate patterns. Second contact plugs are formed over the semiconductor substrate between gate patterns and disposed alternately with the first contact plugs. The second contact plugs having a height greater than the first contact plugs. First and second conductive pads are connected to the first contact plugs. First and second pad contact plugs are formed on extended edge portions of the first and second conductive pads. First bit lines are connected to the first and second pad contact plugs, and second bit lines are connected to the second contact plugs.
1. A flash memory device comprising:
a semiconductor substrate having gate patterns;
first contact plugs formed on the semiconductor substrate between the gate patterns;
second contact plugs disposed alternately with the first contact plugs on the semiconductor substrate between the gate patterns, the second contact plugs having a height greater than the first contact plugs;
first and second conductive pads connected to the first contact plugs;
first and second pad contact plugs formed on extended edge portions of the first and second conductive pads;
first bit lines connected to the first and second pad contact plugs; and
second bit lines connected to the second contact plugs.
2. The flash memory device of claim 1 , wherein the gate patterns form drain select lines.
3. The flash memory device of claim 1 , wherein the first and second conductive pads are formed alternately and extend in opposite directions.
4. The flash memory device of claim 1 , wherein the first and second conductive pads intersect the gate patterns and extend over word lines.
5. The flash memory device of claim 1 , wherein a width of a portion of the first and second conductive pads connected to the first and second pad contact plugs is greater than a width of a portion of the first and second conductive pads connected to the first contact plugs.
6. The flash memory device of claim 1 , wherein a height of the second contact plugs is substantially equal to a sum of a height of the first contact plug, a height of the first or second conductive pad, and a height of the first or second pad contact plug.
7. The flash memory device of claim 1 further comprising:
a first insulating layer in which first contact holes are formed to define areas in which the first contact plugs are to be formed;
a second insulating layer in which first and second pad holes are formed to define areas in which the first and second conductive pads are to be formed; and
a third insulating layer in which first and second pad contact holes are formed to define areas in which the first and second pad contact plugs are to be formed.
8. The flash memory device of claim 7 , wherein the second contact plugs are formed within second contact holes extending through the first, second, and third insulating layers.
9. The flash memory device of claim 8 further comprising a spacer on sidewalls of any one of the first contact holes and, the second contact holes.
10. The flash memory device of claim 9 , wherein the spacer is formed from a material having an etch selectivity different than an etch selectivity of the first, second, and third insulating layers.
11. The flash memory device of claim 10 , wherein the spacer is formed of nitride-based material.
12. The flash memory device of claim 1 , wherein the first and second contact plugs are connected to drain junctions formed on the semiconductor substrate between the gate patterns.