Silicon crystallization apparatus and silicon crystallization method thereof

• US 20050142819A1
• Filed: 12/23/2004
• Published: 06/30/2005
• Est. Priority Date: 12/24/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kim, Young Joo, Jung, Yun Ho
• Granted Patent: US 7,728,256 B2
• Time in Patent Office: Days
• US Class Current: 438/487
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/0823 Devices involving rotation of the workpiece
• CPC Class Codes: B23K 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: B23K 37/0461 Welding tables
• CPC Class Codes: C30B 11/005 by irradiation or electric discharge
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0268 Shape of mask
• CPC Class Codes: H01L 21/68 for positioning, orientation or alignment

Abstract

A novel silicon crystallization apparatus and a silicon crystallization method renders it is possible to form alignment key without additional photolithography, and to adjust a substrate to a correct position by sensing a deviation of the substrate when the substrate is loaded. The silicon crystallization apparatus includes a moving stage being moved in a horizontal direction, and a fixing plate provided in the moving stage, to fix a substrate. A rotating frame is provided in the moving stage, to rotate the fixing plate.

Claims

1. A stage for crystallization comprising:

a moving stage that can move in a horizontal direction;

a fixing plate provided in the moving stage, the fixing plate for fixing a substrate; and

a rotating frame provided in the moving stage, the rotating frame for rotating the fixing plate.

2. The stage for crystallization of claim 1, further comprising:

a plurality of adsorption pins provided in the fixing plate, the adsorption pins capable of being moved up and down; and

a vacuum groove formed in a surface of the fixing plate, the vacuum groove capable of adsorbing the substrate.

3. The stage for crystallization of claim 2, wherein, when the substrate is loaded, the adsorption pins are projecting above the fixing plate so as to fix the substrate, and then the fixing plate is moved down while fixing the substrate, so that the substrate is loaded onto the surface of the fixing plate.

4. The stage for crystallization of claim 2, wherein, when the substrate is unloaded, the adsorption pins are projecting above the fixing plate, so that the substrate is spaced apart from the fixing plate.

5. The stage for crystallization of claim 2, wherein the vacuum groove has a lattice shape.

6. A silicon crystallization apparatus comprising:

a stage for fixing a substrate having silicon deposited thereon, the stage being rotatably and movably provided with the substrate in a horizontal direction;

a sensing device for sensing the substrate fixed to the stage, and controlling the movement of the stage to align the substrate; and

an optical device for crystallizing the silicon by irradiating laser beams to the substrate.

7. The silicon crystallization apparatus of claim 6, wherein the optical device includes:

a laser beam generator;

a focusing lens to focus the laser beams;

a mask to dividedly irradiate the focused laser beams onto the substrate when forming alignment keys;

a crystallization mask to selectively irradiate the focused laser beams onto the substrate when performing a crystallization process; and

a reduction lens to reduce the laser beams passing through the mask for formation of the alignment keys and the crystallization mask.

8. The silicon crystallization apparatus of claim 6, wherein the stage includes:

a moving stage for moving in a horizontal direction;

a fixing plate provided in the moving stage so as to fix the substrate; and

a rotating frame provided in the moving stage so as to rotate the fixing plate.

9. The silicon crystallization apparatus of claim 8, further comprising:

a plurality of adsorption pins provided in the fixing plate, the adsorption pins capable of being moved up and down; and

a vacuum groove provided in the surface of the fixing plate.

10. The silicon crystallization apparatus of claim 9, wherein, when the substrate is loaded, the adsorption pins project above the fixing plate so as to fix the substrate, and then the fixing plate is moved down while fixing the substrate, so that the substrate is loaded on the surface of the fixing plate.

11. The silicon crystallization apparatus of claim 9, wherein, when the substrate is unloaded, the adsorption pins project above the fixing plate, so that the substrate is spaced apart from the fixing plate.

12. The silicon crystallization apparatus of claim 9, wherein the vacuum groove has a lattice shape.

13. The silicon crystallization apparatus of claim 6, wherein the sensing device senses corner coordinates of the substrate.

14. The silicon crystallization apparatus of claim 6, wherein the sensing device includes at least first, second, and third sensors.

15. The silicon crystallization apparatus of claim 14, wherein the first and second sensors are positioned to correspond with the two corner coordinates of the length-side direction of the substrate, and the third sensor is positioned to correspond with the corner coordinates of the width-side direction of the substrate.

16. The silicon crystallization apparatus of claim 14, wherein the first, second, and third sensors comprise CCD cameras.

17. The silicon crystallization apparatus of claim 14, wherein the first, second, and third sensors comprise LD sensors.

18. A silicon crystallization method, which comprises:

providing a silicon crystallization apparatus including an optical device for generating laser beams, a stage for fixing a substrate having silicon deposited thereon, for being rotatably and movably provided with the substrate in a horizontal direction, and a sensing device for sensing the position of the substrate;

forming an amorphous silicon layer over an entire surface of the substrate defined as a display area and a non-display area;

fixing the substrate to the stage;

aligning the substrate by sensing the fixed substrate with the sensing device, and moving and/or rotating the stage;

forming alignment keys on predetermined portions of the non-display area of the substrate by correspondingly placing a mask for formation of alignment key above the substrate; and

crystallizing the amorphous silicon by correspondingly providing a mask for crystallization above the substrate.

19. The silicon crystallization method of claim 18, wherein the process of aligning the substrate includes:

positioning first and second sensors to correspond with the corner coordinates of a length-side direction of the substrate, and positioning a third sensor to correspond with corner coordinates of a width-side direction of the substrate, according to the size of the substrate;

detecting the corner coordinates of the substrate with the first, second, and third sensors; and

moving the stage along the X-axis and the Y-axis directions, and/or rotating the stage, so as to detect the corner coordinates of the substrate from all of the first, second, and third sensors.

20. The silicon crystallization method of claim 19, wherein the method of moving the stage along the X-axis and the Y-axis directions, and of rotating the stage, includes:

minutely moving the stage along the (+)(−

)X-axis direction so as to sense the corner coordinates of the substrate from the third sensor, if the corner coordinates of the substrate are detected from the first and second sensors, and not detected from the third sensor;

minutely moving the stage along the (+)(−

)Y-axis direction so as to sense the corner coordinates of the substrate from the first and second sensors, if the corner coordinates of the substrate are detected from the third sensor, and not detected from the first and second sensors; and

rotating the stage so as to sense the corner coordinates of the substrate from both the first and second sensors, and moving the stage along the (+)(−

)X-axis direction so as to sense the corner coordinates of the substrate from the third sensor, if the corner coordinates are detected from any one of the first and second sensors.

21. The silicon crystallization method of claim 18, wherein the alignment key is formed in a shape of ‘

’

.

22. The silicon crystallization method of claim 18, wherein, when forming the alignment keys, the laser beams irradiates at a first energy density.

23. The silicon crystallization method of claim 22, wherein the first energy density is set at an intensity suitable for ablating the amorphous silicon layer.

24. The silicon crystallization method of claim 18, wherein, when performing the crystallization process, the laser beams irradiates at a second energy density.

25. The silicon crystallization method of claim 24, wherein the second energy density is determined as an intensity to completely melt the amorphous silicon layer.

26. The silicon crystallization method of claim 18, wherein the process of crystallizing the amorphous silicon layer is performed using a first step of selectively crystallizing predetermined portions of the display area, and a second step of crystallizing a driving circuit part of the non-display area.

27. A silicon crystallization method, which comprises:

providing a silicon crystallization apparatus including an optical device for generating laser beams, a stage for fixing a substrate having silicon deposited thereon, and for being rotatably and movably provided with the substrate in a horizontal direction, and a sensing device for determining the position of the substrate;

forming an amorphous silicon layer over an entire surface of the substrate defined as a display area and a non-display area;

fixing the substrate to the stage;

aligning the substrate by sensing the substrate fixed on the stage with the sensing device, and moving and/or rotating the stage;

forming alignment keys on predetermined portions of the non-display area by correspondingly providing a mask for formation of alignment key above the substrate;

crystallizing the amorphous silicon on predetermined portions of the display area by correspondingly placing a first crystallization mask above the substrate; and

crystallizing the amorphous silicon of the non-display area by correspondingly placing a second crystallization mask above the substrate.

28. The silicon crystallization method of claim 27, wherein the process of aligning the substrate includes:

positioning first and second sensors to correspond with the corner coordinates of a length-side direction of the substrate, and positioning a third sensor to correspond with the corner coordinates of a width-side direction of the substrate, according to the size of the substrate;

detecting the corner coordinates of the substrate with the first, second, and third sensors; and

moving the stage along the X-axis and the Y-axis directions, and/or rotating the stage, so as to detect the corner coordinates of the substrate from all of the first, second, and third sensors.

29. The silicon crystallization method of claim 28, wherein the method of moving the stage along the X-axis and the Y-axis directions, and of rotating the stage, includes:

minutely moving the stage along the (+)(−

)X-axis direction so as to sense the corner coordinates of the substrate from the third sensor, if the corner coordinates of the substrate are detected from the first and second sensors, and not detected from the third sensor;

minutely moving the stage along the (+)(−

)Y-axis direction so as to sense the corner coordinates of the substrate from the first and second sensors, if the corner coordinates of the substrate are detected from the third sensor, and not detected from the first and second sensors; and

rotating the stage so as to sense the corner coordinates of the substrate from both the first and second sensors, and moving the stage along the (+)(−

)X-axis direction so as to sense the corner coordinates of the substrate from the third sensor, if the corner coordinates are detected from any one of the first and second sensors.

30. The silicon crystallization method of claim 27, wherein the alignment key has a shape of ‘

’

.

31. The silicon crystallization method of claim 27, wherein, when forming the alignment keys, the laser beams irradiates at a first energy density.

32. The silicon crystallization method of claim 31, wherein the first energy density is set at an intensity suitable for ablating the amorphous silicon layer.

33. The silicon crystallization method of claim 27, wherein when performing the crystallization process, the laser beams irradiates at a second energy density.

34. The silicon crystallization method of claim 33, wherein the second energy density is set at an intensity of completely melting the amorphous silicon layer.

35. The silicon crystallization method of claim 27, wherein the process of crystallizing the amorphous silicon with the first crystallization mask is performed while sensing an interval between the alignment key and the predetermined portion of the substrate irradiated with the laser beams.

36. The silicon crystallization method of claim 27, wherein the first crystallization mask comprises an open part and a closed part, and a length and a width in the open part of the first crystallization mask are controlled according to a size of a semiconductor layer in each pixel.

37. The silicon crystallization method of claim 27, wherein the first crystallization mask includes at least one pattern block corresponding to a semiconductor layer part in each pixel.

38. The silicon crystallization method of claim 27, wherein crystallizing the amorphous silicon with the second crystallization mask is performed while sensing an interval between the alignment key and the predetermined portion of the substrate irradiated with the laser beams.