Semiconductor device including memory cell having capacitor

1. A semiconductor device comprising:

a semiconductor substrate;

a memory cell array including a plurality of memory cells formed on the semiconductor substrate and arranged in a matrix in a first direction and a second direction on the surface of the semiconductor substrate;

a plurality of sense amplifiers formed on the semiconductor substrate and including a first sense amplifier and a second sense amplifier; and

a plurality of bit lines extending along the first direction above the memory cell array, and arranged side by side in the second direction,

wherein the plurality of bit lines include a first bit line pair formed in a first wiring layer made up of a pair of bit lines, and a second bit line pair formed in a second wiring layer located above the first wiring layer made up of a pair of bit lines, and

wherein the first bit line pair is connected to the first sense amplifier, and the second bit line pair is connected to the second sense amplifier.

2. The semiconductor device according to claim 1 ,

wherein each memory cell in the plurality of the memory cells includes

a selection transistor including a gate electrode, a bit line contact region formed on one side of the gate electrode, and a source/drain region formed on the other side of the gate electrode, and

a capacitor connected to the source/drain region.

3. The semiconductor device according to claim 2 ,

wherein a portion of the plurality of memory cells arranged along the second direction include a first memory cell group and a second memory cell group,

wherein a plurality of the gate electrodes include a first gate electrode and a second gate electrode, and

wherein each memory cell included in the first memory cell group share the first gate electrode, and each memory cell included in the second memory cell group share the second gate electrode.

4. The semiconductor device according to claim 3 , further comprising:

a plurality of word lines formed in a third wiring layer located above the memory cell array, extending along the second direction, and arranged side by side in the first direction,

wherein the plurality of word lines includes a first word line and a second word line, and

wherein the first word line is connected to the first gate electrode in a first word line contact region, and the second word line is connected to the second gate electrode in a second word line contact region.

5. The semiconductor device according to claim 4 ,

wherein the first memory cell group and the second memory cell group are alternately arranged in the second direction, and

wherein the first word line contact region and the second word line contact region are alternately arranged in the second direction.

6. The semiconductor device according to claim 4 ,

wherein the first wiring layer, the second wiring layer, and the third wiring layer are formed upward in order from the semiconductor substrate.

7. The semiconductor device according to claim 4 ,

wherein the first memory cell group is connected to four bit lines, and the first word line contact region is located at a position dividing the four bit lines into groups each including two bit lines, and

wherein two bit lines of the four bit lines are formed in the same wiring layer and are located in between the other two bit lines formed in a different wiring layer.

8. The semiconductor device according to claim 7 ,

wherein the two bit lines of the four bit lines located in between the other two bit lines are formed in the first wiring layer, and the other two bit lines are formed in the second wiring layer.

9. The semiconductor device according to claim 8 ,

wherein the two bit lines located in between the other two bit lines are arranged to switch, in an intermediate region of a bit line path, from the first wiring layer to the second wiring layer, and

wherein the two other bit lines are arranged to switch, in the intermediate region of a bit line path, from the second wiring layer to the first wiring layer.

10. The semiconductor device according to claim 4 ,

wherein each of the bit lines is connected to the bit line contact region via a conductive plug formed on the bit line contact region,

wherein the first word line is connected to the first gate electrode via a conductive plug formed on the first word line contact region, and

wherein the second word line is connected to the second gate electrode via a conductive plug formed on the second word line contact region.

11. The semiconductor device according to claim 2 ,

wherein the semiconductor substrate includes a plurality of active regions extending in the first direction, and an element isolation region formed between the active regions, and

wherein the capacitor included in each of the active regions is formed in a portion including a wall of the element isolation region.