Polycrystalline silicon thin film, fabrication method thereof, and thin film transistor without directional dependency on active channels fabricated using the same

1. A method of fabricating a polycrystalline silicon thin film to be used in display devices, the method comprising crystallizing amorphous silicon by a laser using a mask comprising line shaped laser transmission patterns and laser non-transmission patterns;

wherein:

the line shaped laser transmission patterns comprise a plurality of line shaped pattern groups arranged perpendicularly to each other; and

the laser non-transmission patterns comprise circular or dot shaped mask patterns.

2. The method according to claim 1 , wherein the circular or dot shaped mask patterns are arranged in circular, triangular, rectangular, or hexagonal shapes.

3. The method according to claim 1 , wherein the circular or dot shaped mask patterns are irregularly arranged.

4. The method according to claim 1 , wherein:

the laser non-transmission patterns further comprise line shaped laser non-transmission patterns between the line shaped laser transmission patterns; and

the line shaped laser transmission patterns are wider than the line shaped laser non-transmission patterns.

5. A method of fabricating a polycrystalline silicon thin film, the method comprising crystallizing amorphous silicon using a mask in which line shaped patterns are mixed with circular or dot shaped patterns;

wherein:

the polycrystalline silicon thin film comprises various shaped grain structures;

the grain structures comprise primary grain boundaries; and

the circular or dot shaped patterns determine an arrangement of the primary grain boundaries in the polycrystalline silicon thin film.

6. A method of fabricating a polycrystalline silicon thin film to be used in display devices, the method comprising crystallizing amorphous silicon by a laser using a mask comprising:

a first mask section comprising first line shaped laser transmission patterns oriented in a first direction;

a second mask section comprising second line shaped laser transmission patterns oriented in a second direction perpendicular to the first direction; and

a third mask section comprising circular or dot shaped laser non-transmission patterns.

7. The method according to claim 6 , wherein the circular or dot shaped laser non-transmission patterns are irregularly arranged.

8. The method according to claim 6 , wherein the second mask section is disposed between the first mask section and the third mask section.

9. The method according to claim 6 , wherein the first mask section, the second mask section, and the third mask section occupy an entire area of the mask.

10. The method according to claim 6 , wherein:

a height of each of the first mask section, the second mask section, and the third mask section is equal to a height of the mask; and

a width of each of the first mask section, the second mask section, and the third mask section is substantially equal to one-third of a width of the mask.

11. The method according to claim 10 , wherein the width of the mask is greater than the height of the mask.

12. The method according to claim 6 , wherein:

the first mask section further comprises first line shaped laser non-transmission patterns between the first line shaped laser transmission patterns;

the second mask section further comprises second line shaped laser non-transmission patterns between the second line shaped laser transmission patterns;

the first line shaped laser transmission patterns are wider than the first line shaped laser non-transmission patterns; and

the second line shaped laser transmission patterns are wider than the second line shaped laser non-transmission patterns.

13. The method according to claim 6 , wherein:

the polycrystalline silicon thin film comprises primary grain boundaries; and

the circular or dot shaped laser non-transmission patterns determine an arrangement of the primary grain boundaries in the polycrystalline silicon thin film.