Three-dimensional semiconductor device

1. A three-dimensional semiconductor device, comprising:

a first cell region, a second cell region, and a via plug region disposed between the first cell region and the second cell region;

a word line stack disposed in the first cell region, the via plug region, and the second cell region, the word line stack including a plurality of word lines and a plurality of interlayer insulating layers, which are alternately stacked; and

a plurality of via plugs exclusively connected to the plurality of the word lines, respectively, by vertically penetrating through the word line stack in the via plug region, wherein

the via plugs are arranged in a zigzag pattern in a row direction from a top view, and

diameters of the via plugs increase in the row direction.

2. The three-dimensional semiconductor device of claim 1 , wherein the via plug region is divided into a plurality of sites arranged in the row direction, and

a same number of the via plugs are disposed in each of the plurality of the sites.

3. The three-dimensional semiconductor device of claim 2 , wherein an average of diameters of the via plugs in each of the plurality of the sites increases in the row direction.

4. The three-dimensional semiconductor device of claim 2 , wherein

the via plugs are formed in via holes vertically penetrating through the word line stack, and

an inner wall of a via hole has a sill shapes formed on the inner wall.

5. The three-dimensional semiconductor device of claim 4 , wherein a first one of the via holes disposed in a first one of the plurality of sites has a different number of the sill shapes than a second one of the via holes disposed in a second one of the plurality of sites.

6. The three-dimensional semiconductor device of claim 1 , wherein the via plugs have different vertical lengths.

7. The three-dimensional semiconductor device of claim 1 , wherein the word lines laterally extend from the first cell region across the via plug region to the second cell region.

8. The three-dimensional semiconductor device of claim 1 , wherein at least two of the via plugs overlap with each other in a column direction from the top view.

9. The three-dimensional semiconductor device of claim 1 , wherein pitches of the via plugs in the row direction are the same from the top view.

10. The three-dimensional semiconductor device of claim 1 , wherein pitches of the via plugs increase in the row direction.

11. The three-dimensional semiconductor device of claim 1 , wherein the via plugs have a vertical sidewall profile.

12. The three-dimensional semiconductor device of claim 1 , wherein the via plugs have an inclined sidewall profile.

13. A three-dimensional semiconductor device, comprising:

a first cell region, a second cell region, and a via plug region disposed between the first cell region and the second cell region;

a word line stack disposed in the first cell region, the via plug region, and the second cell region, the word line stack including a plurality of word lines and a plurality of interlayer insulating layers that are alternately stacked; and

a plurality of via plugs exclusively connected to the plurality of the word lines, respectively, by vertically penetrating through the word line stack, wherein

each of the plurality of word lines laterally extend from the first cell region across the via plug region to the second cell region, and

the plurality of via plugs zigzag in a row direction from a top view.

14. The three-dimensional semiconductor device of claim 13 , wherein each of the plurality of word lines is commonly connected to memory cells disposed respectively in the first and second cell regions.

15. The three-dimensional semiconductor device of claim 13 , wherein

the via plug region is divided into a plurality of sites,

each of the plurality of sites includes a same number of the via plugs, and

the via plugs disposed in each of the sites has a different vertical length.

16. The three-dimensional semiconductor device of claim 13 , wherein

the plurality of via plugs are formed respectively in via holes vertically penetrating through the word line stack, and

at least one of the via holes has a sill shape formed on an inner wall.

17. The three-dimensional semiconductor device of claim 16 , wherein

the via plug region is divided into a plurality of sites, and

the via holes disposed in a site among the plurality of sites each has the same number of the sill shapes.

18. The three-dimensional semiconductor device of claim 16 , wherein

the via plug region is divided into a plurality of sites, and

the via holes disposed in different sites have different numbers of the sill shapes.

19. A three-dimensional semiconductor device, comprising:

a first cell region and a via plug region;

a word line stack disposed in the first cell region and the via plug region, the word line stack including a plurality of word lines and a plurality of interlayer insulating layers, which are alternately stacked; and

a plurality of via plugs exclusively connected to the plurality of the word lines, respectively, by vertically penetrating the word line stack in the via plug region, wherein

each of the plurality of word lines laterally extends from the first cell region to the via plug region, and

diameters of the plurality of via plugs increase in a row direction from a top view.

20. The three-dimensional semiconductor device of claim 19 , wherein

the via plug region is divided into a plurality of sites arranged in the row direction,

a same number of the via plugs is disposed in each of the plurality of sites,

the via plugs are formed in via holes vertically penetrating the word line stack,

the via holes have sill shapes formed on an inner wall, and

a number of the sill shapes of the via holes in one of the sites is different from a number of the sill shapes of the via holes in another one of the sites.