Silicon crystallization system and silicon crystallization method using laser
View Patent ↗A silicon crystallization system includes a vibration device for vibrating a linear laser beam along a longer-axis direction of the linear laser beam. A vibration frequency at which the laser beam is vibrated is periodically generated and randomly changes within a predetermined range.
1. A silicon crystallization system, comprising:
a vibration device configured to vibrate a linear laser beam in a longer-axis direction of the linear laser beam, the vibration device configured to periodically generate and randomly change a vibration frequency, within a predetermined range, at which the laser beam is vibrated, wherein a difference between a newly generated vibration frequency of the linear laser beam in a longer-axis direction and an immediately previous vibration frequency of the linear laser beam in a longer-axis direction that has already been generated is greater than 2 Hz.
2. The system as claimed in claim 1 , wherein a generation period of the vibration frequency is the same as a pulse period of the laser beam.
3. The system as claimed in claim 1 , wherein a generation period of the vibration frequency is longer than a pulse period of the laser beam.
4. The system as claimed in claim 1 , wherein the vibration frequency has a uniform distribution.
5. The system as claimed in claim 4 , wherein the newly generated vibration frequency is not the same as the immediately previous vibration frequency that has been already generated.
6. The system as claimed in claim 1 , wherein the vibration frequency has a Gaussian distribution.
7. The system as claimed in claim 6 , wherein the newly generated vibration frequency is not the same as the immediately previous vibration frequency that has been already generated.
8. The system as claimed in claim 1 , further comprising an optical system comprising a mirror that changes the energy distribution of the laser beam and the path of the laser beam.
9. The system as claimed in claim 8 , wherein the vibration device vibrates the mirror.
10. The system as claimed in claim 9 , wherein the vibration device comprises:
a vibration operator reciprocally moving an end of the mirror;
a controller comprising a driver for driving the vibration operator;
a pulse generator generating a drive signal of the vibration operator; and
a vibration frequency controller generating a vibration frequency of the drive signal.
11. The system as claimed in claim 10 , wherein the vibration frequency controller randomly modulates the amplitude of the drive signal.
12. The system as claimed in claim 1 , wherein the vibration frequency is previously set as one vibration frequency set having a plurality of randomly changing values.
13. The system as claimed in claim 12 , wherein the number of vibration frequencies included in the pre-set vibration frequency set is
Cell
width
Scan
interval
of
laser
beam
or smaller.
14. The system as claimed in claim 12 , wherein the number of vibration frequencies included in the pre-set vibration frequency set is
Width
of
mother
substrate
Scan
interval
of
laser
beam
or smaller.
15. The system as claimed in claim 12 , wherein the number of vibration frequencies included in the pre-set vibration frequency set is
(
Number
of
mother
substrates
included
in
one
lot
)
×
(
Width
of
mother
substrate
)
Scan
interval
of
laser
beam
or smaller.
16. The system as claimed in 12 , further comprising:
an optical system,
wherein the optical system comprises a mirror that changes an energy distribution of the laser beam and the path of the laser beam.
17. The system as claimed in 16 , wherein the vibration device vibrates the mirror.
18. The system as claimed in 16 , wherein the optical system comprises a homogenizer array for forming the linear shape of the laser beam, and a plurality of lens groups.
19. The system as claimed in 18 , wherein the vibration device comprises a vibration operator reciprocally moving an end of the mirror, a controller comprising a driver for driving the vibration operator, a pulse generator generating a drive signal of the vibration operator, and a vibration frequency storage unit storing the vibration frequency included in the drive signal.
20. The system as claimed in 19 , wherein the amplitude of the drive signal is previously set as a randomly changing value in the vibration frequency storage unit.
21. A silicon crystallization method, comprising:
preparing a substrate with an amorphous silicon thin film formed thereon; and
irradiating a linear laser beam onto the amorphous silicon thin film to form polycrystalline silicon, irradiating including vibrating the laser beam in a longer-axis direction at a vibration frequency that is periodically generated and randomly changed within a predetermined range, wherein a difference between a newly generated vibration frequency of the linear laser beam in a longer-axis direction and an immediately previous vibration frequency of the linear laser beam in a longer-axis direction that has already been generated is greater than 2 Hz.
22. The method as claimed in claim 21 , wherein a generation period of the vibration frequency is the same as a pulse period of the laser beam.
23. The method as claimed in claim 21 , wherein a generation period of the vibration frequency is longer than a pulse period of the laser beam.
24. The method as claimed in claim 21 , wherein the vibration frequency has a uniform distribution.
25. The method as claimed in claim 21 , wherein the vibration frequency has a Gaussian distribution.
26. The method of claim 21 , wherein the vibration frequency is previously set as one vibration frequency set having a plurality of randomly changing values and stored in a vibration frequency storage unit, and the vibration frequency storage unit transfers the pre-set vibration frequency set to the optical system.
27. The method as claimed in claim 26 , wherein the number of vibration frequencies included in the pre-set vibration frequency set is
Cell
width
Scan
interval
of
laser
beam
or smaller.
28. The method as claimed in claim 26 , wherein the number of vibration frequencies included in the pre-set vibration frequency set is
Width
of
mother
substrate
Scan
interval
of
laser
beam
or smaller.
29. The method as claimed in claim 26 , wherein the number of vibration frequencies included in the pre-set vibration frequency set is
(
Number
of
mother
substrates
included
in
one
lot
)
×
(
Width
of
mother
substrate
)
Scan
interval
of
laser
beam
or smaller.