CN114101902B

CN114101902B - Optical system and laser irradiation apparatus including the same

Info

Publication number: CN114101902B
Application number: CN202110375989.4A
Authority: CN
Inventors: 申东勋; 奇相勋; 朴商万; 吴世旭; 禹皓植; 刘光炫; 李泰沅; 李洪鲁
Original assignee: Samsung Display Co Ltd
Current assignee: Samsung Display Co Ltd
Priority date: 2020-09-01
Filing date: 2021-04-08
Publication date: 2026-01-23
Anticipated expiration: 2041-04-08
Also published as: KR102836621B1; KR20220030462A; CN114101902A

Abstract

An optical system and a laser irradiation apparatus including the same are provided. The laser irradiation apparatus includes a first beam module disposed on a traveling path of a laser beam output from a laser output device and blocking both ends of the laser beam to control a length of the laser beam, a projection lens condensing the laser beam passing through the first beam module, a second beam module disposed on a traveling path of the laser beam passing through the projection lens and controlling a length of the laser beam passing through the projection lens, and a beam cutter disposed on a traveling path of the laser beam passing through the second beam module and controlling a length of the laser beam passing through the second beam module.

Description

Optical system and laser irradiation apparatus including the same

Technical Field

The present disclosure relates to an optical system and a laser irradiation apparatus including the same, and more particularly, to a laser irradiation apparatus for crystallizing an amorphous silicon film and an optical system used in the laser irradiation apparatus.

Background

In order to manufacture a device in which polycrystalline silicon is used as an active layer of a thin film transistor as a switching element such as an OLED (Organic LIGHT EMITTING DISPLAY), a process of depositing an amorphous silicon film and crystallizing it is required. The most commonly used method in the crystallization process is a method in which a laser scanner uniformly irradiates an amorphous silicon film formed on a substrate with laser light of a certain energy, thereby achieving polycrystallization. In such a laser polycrystallization method, it is important to uniformly transfer laser energy to the amorphous silicon film so as to uniformly form the polysilicon film over the entire substrate.

In the case of the conventional laser irradiation apparatus, in order to adjust the length of the laser beam irradiated to the amorphous silicon film, a beam cutter is disposed at the final end of the optical system so as to pass only the laser beam to be irradiated and block the remaining laser beam. At this time, in order to perform precise layout adjustment, a beam cutter is disposed close to the substrate. The blocked laser beam transfers energy to the beam cutter, which generates high temperature heat that creates a thermal gradient around the circumference of the beam cutter, thereby inducing an air density differential. As a result, laser scattering is generated partially, and as a result, irregular stains are generated at the corners. That is, uniformity of the polysilicon film is hindered.

Disclosure of Invention

Embodiments of the present invention have been made to solve the problems in the prior art and provide a laser irradiation apparatus that can form a uniform polysilicon film.

Embodiments of the present invention provide an optical system for irradiating uniform laser light.

A laser irradiation apparatus according to an embodiment of the present invention includes a laser output unit, a first beam module disposed on a traveling path of a laser beam output from the laser output unit and blocking both ends of the laser beam to control a length of the laser beam, a projection lens condensing the laser beam passing through the first beam module, a second beam module disposed on a traveling path of the laser beam passing through the projection lens and controlling a length of the laser beam passing through the projection lens, and a beam cutter disposed on a traveling path of the laser beam passing through the second beam module and controlling a length of the laser beam passing through the second beam module.

The lengths of the laser beams passing through the first beam module, the second beam module, and the beam cutter may be the same.

It may be that the real light beam passes through the second beam module and the diffracted light beam is blocked by the second beam module, and the real light beam passes through the beam cutter and the diffracted light beam is blocked by the beam cutter, among the laser beams passing through the first beam module.

The first beam module and the second beam module may include a support body and a pair of beam blocking modules supported by the support body, respectively, the beam blocking modules of the first beam module may have a heat dissipation structure, and the beam blocking modules of the first beam module may include a substrate and a plurality of protruding walls formed on the substrate and side by side with each other. The heat radiation structure of the beam blocking module of the first beam module may be disposed on a surface of a side on which the laser beam is irradiated.

The beam blocking module of the second beam module may have a heat radiation structure, the beam blocking module of the second beam module may include a substrate and a plurality of protruding walls formed on the substrate and side by side with each other, and the heat radiation structure of the beam blocking module of the second beam module may be disposed on a surface of one side where the laser beam is irradiated.

The distance between the pair of beam blocking modules of the first and second beam modules may be adjustable.

The beam cutter may include a support body and a pair of beam blocking modules supported by the support body, the beam blocking modules of the beam cutter including a support structure portion and a laser beam blocking portion formed of a material having a larger specific heat than the support structure portion. Specifically, the support structure portion may be formed of SUS, and the laser beam blocking portion may be formed of quartz. The distance between the pair of beam blocking modules of the beam cutter may be adjustable.

The laser irradiation apparatus according to an embodiment of the present invention may further include a reflecting mirror that reflects the laser beam passing through the first beam module and makes it travel toward the projection lens.

An optical system according to an embodiment of the present invention may include a first beam module that controls a cross-sectional size of a laser beam, a projection lens that condenses the laser beam passing through the first beam module, a second beam module that is disposed on a traveling path of the laser beam passing through the projection lens and controls the cross-sectional size of the laser beam passing through the projection lens, and a beam cutter that is disposed on a traveling path of the laser beam passing through the second beam module and controls the cross-sectional size of the laser beam passing through the second beam module, wherein lengths of cross-sections of the laser beams passing through the first beam module, the second beam module, and the beam cutter are the same.

The first beam module, the second beam module, and the beam cutter may include a support body and a pair of beam blocking modules supported by the support body, respectively, the beam blocking modules of the first beam module and the second beam module may have a heat radiation structure, and the beam blocking module of the beam cutter may include a support structure portion and a laser beam blocking portion formed of a material having a larger specific heat than the support structure portion.

An embodiment of the present invention may be directed to an optical system further comprising a mirror that reflects the laser beam passing through the first beam module and makes it travel toward the projection lens.

(Effects of the invention)

According to embodiments of the present invention, the beam module blocks the laser beam having strong energy in advance, and the beam cutter disposed near the substrate blocks only the weak beam caused by diffraction, so that uniformity of the irradiated laser beam can be improved.

In addition, a heat radiation structure is formed in the beam module to guide air cooling, and a material such as quartz having a large specific heat is applied to the beam cutter, so that an increase in temperature around the beam cutter can be suppressed.

Drawings

Fig. 1 is a perspective view of a laser irradiation apparatus including an optical module according to an embodiment of the present invention.

Fig. 2 is a side view of an optical module used in the laser irradiation apparatus of fig. 1.

Fig. 3 is a schematic diagram showing a function of controlling the length of a laser beam by an optical assembly used in the laser irradiation apparatus of fig. 1.

Fig. 4 is a front view (viewed from above) of a heat dissipation structure of a beam module used in an optical assembly according to an embodiment of the present invention.

Fig. 5 is a left side view of the beam module of fig. 4.

Fig. 6 is an underside view of the beam module of fig. 4.

Fig. 7 is a partial cross-sectional view of a beam cutter used in an optical assembly in accordance with an embodiment of the present invention.

Fig. 8 is a schematic diagram showing the function of a beam cutter used in an optical assembly according to an embodiment of the present invention.

Symbol description:

1, a laser output device, 10, 40, a light beam module, 20, a reflector, 30, a projection lens and 50, a light beam cutter.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in a variety of different forms and is not limited to the embodiments described herein.

For the purpose of clarity of explanation, parts irrelevant to the explanation are omitted, and the same or similar constituent elements are given the same reference numerals throughout the specification.

The size and thickness of each illustrated component are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to the illustrated case. In the drawings, thicknesses are shown exaggerated for clarity of presentation of layers and regions. In addition, in the drawings, the thicknesses of partial layers and regions are exaggeratedly shown for convenience of explanation.

Further, when a layer, a film, a region, a plate, or the like is located on or over other portions, it includes not only the case of directly located on other portions but also the case of including other portions therebetween. Conversely, when a portion is directly above another portion, it means that there is no other portion therebetween. Further, being located on or above the reference portion means being located on or below the reference portion, and does not necessarily mean being located on or above the gravitational direction side.

In addition, when a certain component is included in a certain part throughout the specification, the inclusion of other components is not excluded unless the contrary is stated, but other components may be included.

In the present specification, "in plane" refers to a case where the object portion is viewed from above, and "in section" refers to a case where the section of the object portion is vertically taken from a side view.

Fig. 1 is a perspective view of a laser irradiation apparatus including an optical module according to an embodiment of the present invention, fig. 2 is a side view of the optical module used in the laser irradiation apparatus of fig. 1, and fig. 3 is a schematic view showing a function of controlling a length of a laser beam by the optical module used in the laser irradiation apparatus of fig. 1.

The laser irradiation apparatus according to an embodiment of the present invention may include the laser output device 1 and an optical system. The optical system may include a first beam module 10, a mirror 20, a projection lens 30, a second beam module 40, and a beam cutter 50.

The laser output device 1 is a device that outputs a laser beam having a predetermined width and length, and the optical system is an optical device that condenses the laser beam output by the laser output device 1 and changes the width and length of the laser beam to a desired size. The laser output device 1 may generate a pulse laser, and one of various types of lasers such as a gas laser and a solid-state laser may be used.

The first beam module 10 constituting the optical system may be disposed on a traveling path of the laser beam output from the laser output 1, and may include a support bar 14 and a beam blocking module 13 provided on the support bar 14. The support rod 14 may be formed of a transparent material or may have a slit formed in the center so as to allow the laser beam to pass therethrough without loss and to movably support the beam blocking module 13. Two beam blocking modules 13 may be arranged in pairs on one side of the support bar 14. The distance between the two beam blocking modules 13 can be adjusted, by which the length of the laser beam can be adjusted. I.e. the cross-sectional size of the laser beam. The beam blocking module 13 may have a heat dissipation structure, whereby heat generated by the blocked laser beam may be dissipated in air. The heat radiation structure for the beam blocking module 13 will be described in detail later with reference to fig. 4 to 6. On the other hand, the support bar 14 is an alternative configuration, and instead of the support bar 14, a support structure 15 that individually supports the beam blocking modules 13 may be used to individually control the positions of the beam blocking modules 13. The support bar 14 and the support structure 15 are merely two examples of the support of the beam blocking module 13, and various structures of the support may be employed.

The mirror 20 is an element that reflects the laser beam passing through the first beam module 10 to change the direction of travel toward the projection lens 30.

The projection lens 30 is an element for condensing the laser beam to increase the energy density, and may include a plurality of lenses 31, 32, 33, 34, 35, and the plurality of lenses 31, 32, 33, 34, 35 may each be a convex lens, or may be a spherical lens for the uppermost lens 31 and the lowermost lens 35. As shown in fig. 2, the laser beam may pass through the projection lens 30 while the beam width is narrowed and converged into one line at a predetermined focal distance.

The second beam module 40 may be disposed on a traveling path of the laser beam passing through the projection lens 30, and may include a support bar 44 and a pair of beam blocking modules 43 disposed on the support bar 44. The support rod 44 may be formed of a transparent material or may have a slit formed in the center so as to allow the laser beam to pass therethrough without loss and to movably support the beam blocking module 43. Two beam blocking modules 43 may be provided in pairs on one side of the support bar 44. The distance between the two beam blocking modules 43 is adjustable, by which the length of the laser beam can be adjusted. I.e. the cross-sectional size of the laser beam. The beam blocking module 43 may have a heat dissipation structure, whereby heat generated by the blocked laser beam may be dissipated in air. The heat radiation structure for the beam blocking module 43 will be described in detail later with reference to fig. 4 to 6. On the other hand, the support rod 44 is an alternative configuration, and instead of the support rod 44, a support structure 45 that independently supports the beam blocking modules 43 may be used to independently control the positions of the beam blocking modules 43. The support bar 44 and the support structure 45 are merely two examples of the support of the beam blocking module 43, and various structures of the support may be employed.

The second beam module 40 may be controlled in association with the first beam module 10, and when the laser beam passing through the first beam module 10 passes through the second beam module 40 through the reflecting mirror 20 and the projection lens 30, the distance and position between the two beam blocking modules 43 may be controlled such that the real beam (the laser beam except for a portion where the laser beam is spread and widened by diffraction (hereinafter, referred to as "diffracted beam") entirely passes through and the diffracted beam is blocked.

The beam cutter 50 may be disposed on a traveling path of the laser beam passing through the second beam module 40, and may include a support bar 54 and a pair of beam blocking modules 53 disposed on the support bar 54. The support rod 54 may be formed of a transparent material or may have a slit formed in the center so as to allow the laser beam to pass therethrough without loss and to movably support the beam blocking module 53. Two beam blocking modules 53 may be provided in pairs on one side of the support bar 54. The distance between the two beam blocking modules 53 is adjustable, by which the length of the laser beam can be adjusted. I.e. the cross-sectional size of the laser beam. The beam blocking module 53 may have a portion 531 formed of SUS (steel use stainless, stainless steel) and a portion 532 formed of a substance having a larger specific heat such as quartz. The portion 532 formed of a substance having a larger specific heat may be disposed in a region where the laser beam is irradiated. The matters related thereto will be described in detail later with reference to fig. 7 and 8. On the other hand, the support rod 54 is an alternative configuration, and instead of the support rod 54, a support structure 55 that independently supports the beam blocking module 53 may be used to independently control the position of the beam blocking module 53. The support bar 54 and the support structure 55 are merely two examples of the support of the beam blocking module 53, and various structures of the support may be employed.

The beam cutter 50 may be controlled in association with the first and second beam modules 10 and 40, and a distance between the two beam blocking modules 53 may be controlled such that the real light beam is entirely passed and the diffracted light beam is blocked when the laser beam passing through the second beam module 40 passes through the beam cutter 50. Here, the lengths of the laser beams passing through the first beam module 10, the second beam module 40, and the beam cutter 50 may be the same. That is, the lengths of the sections of the laser beams passing through the first beam module 10, the second beam module 40, and the beam cutter 50 may be the same.

In the laser irradiation apparatus having such a configuration, as shown in fig. 3, the first beam module 10 performs a first cut to adjust the length of the beam with respect to the laser beam outputted from the laser output device 1, and the second beam module 40 performs a second cut with respect to the diffracted beam generated by diffraction while the laser beam travels, so that only the real beam can travel. The beam cutter 50 may perform a third cut with respect to the diffracted beam generated by diffraction while the real beam passing through the second beam module 40 travels, thereby again allowing only the real beam to travel toward the target. Through this process, the first beam module 10 may absorb the laser beam having energy equivalent to 100% of the output laser light by blocking, the second beam module 40 may absorb the diffracted light having energy equivalent to 20% of the output laser light by blocking, and the beam cutter 50 may absorb the diffracted light having energy equivalent to 4% of the output laser light by blocking. Therefore, most of the energy of the blocked laser beam is blocked and absorbed by the first and second beam modules 10 and 40, and the energy of the laser beam blocked and absorbed by the beam cutter 50 is greatly reduced. Thus, heat generated by the beam cutter 50 disposed in the vicinity of the amorphous silicon film can be prevented, and uniformity of the polycrystalline silicon film which is polycrystallized by laser irradiation can be improved.

Fig. 4 is a front view (viewed from above) of a heat radiation structure of a beam module used in an optical assembly according to an embodiment of the present invention, fig. 5 is a left side view of the beam module of fig. 4, and fig. 6 is a lower side view of the beam module of fig. 4.

The beam blocking modules 13, 43 of the first and second beam modules 10, 40 described previously may have a heat radiation structure as shown in fig. 4 to 6. The beam blocking module 13, 43 may include a substrate 131 and a plurality of protruding walls 132 formed side by side with each other on the substrate 131. The plurality of protruding walls 132 may be formed with irregularities for expanding the surface area, and a plurality of protruding columns or protruding structures having other shapes may be formed instead of the protruding walls 132.

When the first beam module 10 and the second beam module 40 are arranged, it may be arranged to irradiate a laser beam toward a face where the plurality of protruding walls 132 are formed. The laser beam irradiated to the plurality of protruding walls 132 is absorbed by the plurality of protruding walls 132 to generate heat, and the generated heat may be propagated through the plurality of protruding walls 132 to be dissipated. As described above, heat generated during cutting of the laser beam is rapidly dissipated by the heat dissipation structure, whereby it is possible to prevent the case where the laser crystallization device is affected by the heat generated at this time or the case where unevenness is generated in the polysilicon film.

Fig. 7 is a partial cross-sectional view of a beam cutter used in an optical assembly according to an embodiment of the present invention, and fig. 8 is a schematic diagram showing the function of the beam cutter used in the optical assembly according to an embodiment of the present invention.

The beam blocking module 53 of the previously described beam cutter 50 may include a portion 531 forming a support structure, and a portion 532 blocking the laser beam as shown in fig. 7. The portion 531 forming the support structure may be formed of a material excellent in durability such as SUS, and the portion 532 blocking the laser beam may be formed of a material having a large specific heat and a low thermal conductivity such as quartz, so that even if heat is generated by the laser beam, the propagation thereof to the periphery can be suppressed.

The following table compares the substance characteristics of SUS forming portion 531 and quartz forming portion 532.

Differentiation of	SUS (sequence number)	Quartz crystal
			Density (g/cm ³)	8.02	2.02
Specific heat (J/Kg. K)	13	749
			Transmittance (%)	0%	1%↓
Melting point (° C)	1399	1170

When such a beam cutter 50 is disposed at the final output end of the laser beam, as shown in fig. 8, the beam-blocking portion 532 formed of a material having a high specific heat and low thermal conductivity blocks the diffracted beam, and only the real beam is irradiated to the target object through the seal box 60. The sealing case 60 is configured to maintain a portion irradiated with laser light in a predetermined gas atmosphere state, and functions to seal a predetermined gas.

As described above, the energy of the diffracted light beam blocked by the light beam blocking portion 532 is only about 4% compared with the initial output, and therefore the generated heat is small, and even this heat is absorbed by the material having a large specific heat and low thermal conductivity, so that the ambient temperature can be prevented from rising.

While the embodiments of the present invention have been described in detail, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the present invention defined in the claims are also within the scope of the present invention.

Claims

1. A laser irradiation apparatus comprising:

A laser output;

A first beam module configured on a traveling path of the laser beam output by the laser output device and blocking both ends of the laser beam to control a length of the laser beam;

a projection lens condensing the laser beam passing through the first beam module;

a second beam module arranged on the traveling path of the laser beam passing through the projection lens and controlling the length of the laser beam passing through the projection lens, and

A beam cutter which is disposed on a traveling path of the laser beam passing through the second beam module and controls a length of the laser beam passing through the second beam module,

Of the laser beams passing through the first beam module, a real beam passes through the second beam module and a diffracted beam is blocked by the second beam module.

2. The laser irradiation apparatus according to claim 1, wherein,

The lengths of the laser beams passing through the first beam module, the second beam module and the beam cutter are the same.

3. The laser irradiation apparatus according to claim 1, wherein,

Of the laser beams passing through the second beam module, a real beam passes through the beam cutter and a diffracted beam is blocked by the beam cutter.

4. The laser irradiation apparatus according to claim 1, wherein,

The first and second beam modules each include a support body and a pair of beam blocking modules supported by the support body.

5. The laser irradiation apparatus according to claim 4, wherein,

The beam blocking module of the first beam module has a heat dissipating structure.

6. The laser irradiation apparatus according to claim 5, wherein,

The beam blocking module of the first beam module includes a substrate and a plurality of protruding walls formed on the substrate and side by side with each other.

7. The laser irradiation apparatus according to claim 5, wherein,

The heat radiation structure of the beam blocking module of the first beam module is disposed on a surface of a side on which the laser beam is irradiated.

8. The laser irradiation apparatus according to claim 4, wherein,

The beam blocking module of the second beam module has a heat dissipating structure.

9. The laser irradiation apparatus according to claim 8, wherein,

The beam blocking module of the second beam module includes a substrate and a plurality of protruding walls formed on the substrate and side by side with each other.

10. The laser irradiation apparatus according to claim 8, wherein,

The heat radiation structure of the beam blocking module of the second beam module is disposed on a surface of a side where the laser beam is irradiated.

11. The laser irradiation apparatus according to claim 4, wherein,

The distance between the pair of beam blocking modules is adjustable.

12. The laser irradiation apparatus according to claim 1, wherein,

The beam cutter includes a support body and a pair of beam blocking modules supported by the support body.

13. The laser irradiation apparatus according to claim 12, wherein,

The beam blocking module of the beam cutter includes a support structure portion and a laser beam blocking portion formed of a material having a larger specific heat than the support structure portion.

14. The laser irradiation apparatus according to claim 13, wherein,

The support structure portion is formed of stainless steel, and the laser beam blocking portion is formed of quartz.

15. The laser irradiation apparatus according to claim 12, wherein,

The distance between the pair of beam blocking modules is adjustable.

16. The laser irradiation apparatus according to claim 1, further comprising:

And a reflecting mirror reflecting the laser beam passing through the first beam module and making it travel toward the projection lens.

17. An optical system, comprising:

a first beam module controlling a cross-sectional size of the laser beam;

a second beam module which is disposed on a traveling path of the laser beam passing through the projection lens and controls a cross-sectional size of the laser beam passing through the projection lens;

a beam cutter which is disposed on a traveling path of the laser beam passing through the second beam module and controls a cross-sectional size of the laser beam passing through the second beam module,

The length of the cross-section of the laser beam passing through the first beam module, the second beam module and the beam cutter is the same,

18. The optical system of claim 17, wherein,

The first beam module, the second beam module, and the beam cutter each include a support body and a pair of beam blocking modules supported by the support body,

The beam blocking modules of the first beam module and the second beam module have a heat dissipation structure,

19. The optical system of claim 18, further comprising: