Liquid crystal display device with at least two contact holes in the pad region having sidewalls with differing slopes

1. A liquid crystal display device comprising:

a signal line and a signal line pad arranged on a substrate in one direction;

an insulating film on a surface of the substrate including the signal line and the signal line pad, the insulating film including at least one contact hole through which a predetermined portion of the signal line pad is exposed; and

a pad electrode formed on the insulating film, and electrically connected with the signal line pad via the at least one contact hole,

wherein the insulating film includes inner side walls defining the at least one contact hole, the at least one contact hole comprises at least one pair of adjacent contact holes, and the slope of the inner side walls between the adjacent contact holes is gentler than the slope of the at least one of the remaining inner side walls of the adjacent contact holes.

2. The liquid crystal display device according to claim 1 , wherein the signal line includes a gate line or a data line.

3. The liquid crystal display device according to claim 1 , wherein the pad electrode is made of a material identical to a material of a pixel electrode included in the liquid crystal display device.

4. The liquid crystal display device according to claim 1 , wherein the at least one contact hole comprises a plurality of contact holes arranged along at least two parallel lines.

5. The liquid crystal display device according to claim 4 , wherein, when the contact holes arranged along each of the at least two parallel lines are divided into a plurality of blocks each including a pair of adjacent contact holes, the slope of the inner side walls between the adjacent contact holes in each odd-numbered block along each odd-numbered line is gentler than the slope of the at least one of the remaining inner side walls of the adjacent contact holes.

6. The liquid crystal display device according to claim 4 , wherein, when the contact holes arranged along each of the at least two parallel lines are divided into a plurality of blocks each including a pair of adjacent contact holes, the slope of the inner side walls between the contact holes in each even-numbered block along each even-numbered line is gentler than the slope of the at least one of the remaining inner side walls.

7. The liquid crystal display device according to claim 1 , wherein the contact hole has a square shape.

8. A liquid crystal display device comprising:

a gate line and a gate pad formed on a substrate;

a gate insulating film formed on the substrate including the gate line and the gate pad;

a data line and a data pad formed on the gate insulating film;

a protective film formed over a surface of the substrate including the data line and the data pad;

at least one first contact hole in the gate insulating film and the protective film, and at least one second contact hole formed in the protective film, to expose predetermined portions of the gate and data pads, respectively; and

a first pad electrode and a second pad electrode connected to the gate and data pads via the at least one first contact hole and the at least one second contact hole, respectively,

wherein each of the at least one first contact hole and the at least one second contact hole includes inner side walls and comprises at least one pair of adjacent contact holes and

wherein the slope of the inner side walls between the adjacent contact holes is gentler than the slope of the at least one of the remaining inner side walls of the adjacent contact holes.

9. The liquid crystal display device according to claim 8 , wherein each of the at least one first contact hole and the at least one second contact hole comprises a plurality of contact holes arranged along at least two parallel lines.

10. The liquid crystal display device according to claim 9 , wherein, when the contact holes arranged along each of the lines are divided into a plurality of blocks each including a pair of adjacent contact holes, the slope of the inner side walls arranged between the contact holes in each odd-numbered block on each odd-numbered line is gentler than the slope of the at least one of the remaining inner side walls.

11. The liquid crystal display device according to claim 9 , wherein, when the contact holes arranged along each of the lines are divided into a plurality of blocks each including a pair of adjacent contact holes, the slope of the inner side walls arranged between the contact holes in each even-numbered block along each even-numbered line is gentler than the slope of the at least one of the remaining inner side walls.

12. The liquid crystal display device according to claim 8 , wherein each of the at least one first contact hole and the at least one second contact hole has a square shape.

13. A method for manufacturing a liquid crystal display device, the method comprising:

forming a plurality of signal lines and a plurality of pads on a substrate;

forming an insulating film over a surface of the substrate including the signal lines and the pads;

forming at least one contact hole in the insulating film by exposing a predetermined portion of each of the pads such that the at least one contact hole comprises at least one pair of adjacent contact holes and each contact hole has at least one inner side walls, wherein a slope of the inner side walls between the adjacent contact holes is gentler than the slope of the at least one of the remaining inner side walls of the adjacent contact holes; and

forming a pad electrode to be connected with the pad via the at least one contact hole.

14. The method according to claim 13 , wherein forming the at least one contact hole comprises:

forming a photoresist over a surface of the insulating film;

patterning the photoresist by exposure and developing processes using a diffraction mask; and

etching the insulating film by use of the patterned photoresist as a mask.

15. The method according to claim 14 , wherein the diffraction exposure mask includes a transmission portion corresponding to the contact hole, a slit corresponding to the inner side wall having the gentler slope, and a shield portion corresponding to the remaining portion of the insulating film.

16. The method according to claim 13 , wherein the at least one contact hole comprises a plurality of contact holes, and the slope of the inner side walls arranged between adjacent ones of the contact holes is gentler than the slope of the at least one of the remaining inner side walls.

17. The method according to claim 13 , wherein the at least one contact hole comprises contact holes arranged along at least two parallel lines.

18. The method according to claim 17 , wherein, when the contact holes arranged along each of the lines are divided into a plurality of blocks each including a pair of adjacent contact holes, the slope of the inner side walls arranged between the contact holes in each odd-numbered block along each odd-numbered line is gentler than the slope of the at least one of the remaining inner side walls.

19. The method according to claim 17 , wherein, when the contact holes arranged along each of the lines are divided into a plurality of blocks each including a pair of adjacent contact holes, the slope of the inner side walls arranged between the contact holes in each even-numbered block along each even-numbered line is gentler than the slope of the at least one of the remaining inner side walls.

20. The method according to claim 13 , wherein the at least one contact hole has a square shape.