Optical system and laser irradiation device comprising the same

Abstract

Provided are an optical system and a laser irradiation apparatus including the same. The laser irradiation apparatus includes a first beam module configured on a path of a laser beam output from a laser output device and blocking both end portions 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 configured on a 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 configured on a 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

TECHNICAL FIELD

[0001] 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 for use in the laser irradiation apparatus. BACKGROUND

[0002] In order to manufacture an apparatus such as an OLED (Organic Light Emitting Display) using a polycrystalline silicon film as an active layer of a thin film transistor serving as a switching element, a process of depositing an amorphous silicon film and crystallizing the same is required. The most commonly used method in the crystallization process is a method of uniformly irradiating a laser of a certain energy to an amorphous silicon film formed on a substrate by a laser scanner, thereby achieving polycrystallization. In this laser polycrystallization method, it is important to uniformly transfer the laser energy to the amorphous silicon film so as to uniformly form a polycrystalline silicon film on the entire substrate.

[0003] 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 to pass only the laser beam to be irradiated and block the remaining laser beam. At this time, in order to perform a precise layout adjustment, the beam cutter is disposed close to the substrate. However, the blocked laser beam can transfer energy to the beam cutter, thereby generating heat of a high temperature, and the heat can generate a thermal gradient in the periphery of the beam cutter, thereby causing a difference in air density. Thus, laser scattering can be partially generated, and as a result, irregular stains can be generated at the corners. That is, the uniformity of the polycrystalline silicon film can be deteriorated. SUMMARY

[0004] Embodiments of the present application are to provide a laser irradiation apparatus capable of forming a uniform polycrystalline silicon film by eliminating the problems of the conventional art.

[0005] Embodiments of the present application are to provide an optical system for irradiating uniform laser.

[0006] An embodiment of the present application relates to a laser irradiation apparatus including: a laser outputter; a first beam module disposed on a traveling path of a laser beam output from the laser outputter and blocking both end portions of the laser beam to control the length of the laser beam; a projection lens condensing the laser beam passed through the first beam module; a second beam module disposed on a traveling path of the laser beam passed through the projection lens and controlling the length of the laser beam passed through the projection lens; and a beam cutter disposed on a traveling path of the laser beam passed through the second beam module and controlling the length of the laser beam passed through the second beam module.

[0007] The length of the laser beams passing through the first beam module, the second beam module, and the beam cutter can be the same.

[0008] Among the laser beams passing through the first beam module, the real light beam passes through the second beam module and the diffracted light beam is blocked by the second beam module, and among the laser beams passing through the second beam module, the real light beam passes through the beam cutter and the diffracted light beam is blocked by the beam cutter.

[0009] The first beam module and the second beam module can 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 having a heat dissipation structure, the beam blocking modules of the first beam module including a substrate and a plurality of protruding walls formed on the substrate and arranged side by side with each other. The heat dissipation structure of the beam blocking modules of the first beam module can be disposed on a surface of a side where the laser beam is irradiated.

[0010] The beam blocking modules of the second beam module can have a heat dissipation structure, the beam blocking modules of the second beam module including a substrate and a plurality of protruding walls formed on the substrate and arranged side by side with each other, the heat dissipation structure of the beam blocking modules of the second beam module being disposed on a surface of a side where the laser beam is irradiated.

[0011] The distance between the pair of beam blocking modules of the first beam module and the second beam module can be adjustable.

[0012] The beam cutter can 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, the laser beam blocking portion being formed of a material having a higher thermal conductivity than the support structure portion. Specifically, the support structure portion can be formed of SUS, and the laser beam blocking portion can be formed of quartz. The distance between the pair of beam blocking modules of the beam cutter can be adjustable.

[0013] The laser irradiation device according to an embodiment of the present disclosure can further include a mirror that reflects the laser beam passing through the first beam module and makes it travel toward the projection lens.

[0014] An embodiment of the present invention relates to an optical system which can include: a first beam module which controls a cross-sectional size of a laser beam; a projection lens which condenses the laser beam which has passed through the first beam module; a second beam module which is disposed on a traveling path of the laser beam which has passed through the projection lens and controls a cross-sectional size of the laser beam which has passed through the projection lens; and a beam cutter which is disposed on a traveling path of the laser beam which has passed through the second beam module and controls a cross-sectional size of the laser beam which has passed through the second beam module, the cross-sectional sizes of the laser beams which have passed through the first beam module, the second beam module, and the beam cutter being the same in length.

[0015] The first beam module, the second beam module, and the beam cutter can 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 having a heat dissipation structure, and the beam blocking modules of the beam cutter including a support structure portion and a laser beam blocking portion, the laser beam blocking portion being formed of a material having a greater specific heat than the support structure portion.

[0016] The optical system according to an embodiment of the present invention can further include a mirror which reflects the laser beam which has passed through the first beam module and makes it travel toward the projection lens.

[0017] (EFFECT OF INVENTION)

[0018] According to the embodiments of the present invention, the beam module blocks a laser beam having a strong energy in advance, and the beam cutter disposed near a substrate blocks only a weak laser beam caused by diffraction, so that the uniformity of the irradiated laser beam can be improved.

[0019] In addition, a heat dissipation structure is formed in the beam module to guide air cooling, and a material having a large specific heat, such as quartz, is applied to the beam cutter, so that the temperature increase around the beam cutter can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a perspective view of a laser irradiation apparatus including an optical assembly according to an embodiment of the present invention.

[0021] Figure 2 FIG. 2 is a side view of an optical assembly used in the laser irradiation apparatus of FIG. 1. Figure 1 FIG. 3 is a side view of an optical assembly used in the laser irradiation apparatus of FIG. 1.

[0022] Figure 3 FIG. 4 is a schematic view showing a function of controlling a length of a laser beam of an optical assembly used in the laser irradiation apparatus of FIG. 1. Figure 1 FIG. 5 is a schematic view showing a function of controlling a length of a laser beam of an optical assembly used in the laser irradiation apparatus of FIG. 1.

[0023] Figure 4is a front view (viewed from above) of a heat dissipation structure of a light beam module used in an optical assembly to which an embodiment of the present application relates.

[0024] Figure 5 is a left side view of the light beam module of Figure 4

[0025] Figure 6 is a lower side view of the light beam module of Figure 4

[0026] Figure 7 is a partial sectional view of a light beam cutter used in an optical assembly to which an embodiment of the present application relates.

[0027] Figure 8 is a schematic view showing a function of a light beam cutter used in an optical assembly to which an embodiment of the present application relates.

[0028] Symbol explanation:

[0029] 1: laser outputter; 10, 40: light beam module; 20: mirror; 30: projection lens; 50: light beam cutter. DETAILED DESCRIPTION

[0030] Hereinafter, each embodiment of the present application will be explained in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry it out. The present application can be realized in various different ways, and is not limited to each embodiment explained herein.

[0031] In order to clearly explain the present application, parts irrelevant to the explanation are omitted, and the same or similar constituent elements are given the same symbols throughout the specification.

[0032] Further, the size and thickness of each constituent illustrated herein are arbitrarily shown for the purpose of explanation, and the present application is not necessarily limited to the illustrated cases. In the drawings, the thickness is exaggerated in order to clearly show each layer and region. Further, in the drawings, the thickness of some layers and regions is exaggerated for the purpose of explanation.

[0033] Further, when a part is positioned on or above another part, it includes not only a case where it is directly positioned on the other part, but also a case where another part is included therebetween. Conversely, when a part is directly positioned on another part, it means that no other part is included therebetween. Further, positioned on or above a part serving as a reference means positioned above or below the part serving as a reference, and does not necessarily mean positioned on or above in the direction of gravity.

[0034] Further, throughout the specification, when a part includes a certain constituent element, it does not exclude other constituent elements unless specifically stated to the contrary, but means that other constituent elements can also be included.​​

[0035] Further, in the entire specification, "on a plane" means a case where an object portion is observed from above, and "in a cross section" means a case where a cross section of the object portion is observed from a side.

[0036] Figure 1 is a perspective view of a laser irradiation apparatus including an optical assembly to which an embodiment of the present application relates, Figure 2 is a side view of an optical assembly used in the laser irradiation apparatus of Figure 1 Figure 3 is a schematic view showing a function of controlling a length of a laser beam by the optical assembly used in the laser irradiation apparatus of Figure 1

[0037] The laser irradiation apparatus to which an embodiment of the present application relates can include a laser outputter 1 and an optical system. The optical system can include a first beam module 10, a mirror 20, a projection lens 30, a second beam module 40, and a beam cutter 50.

[0038] The laser outputter 1 is an apparatus that outputs a laser beam having a predetermined width and length, and the optical system is an optical apparatus that condenses the laser beam output from the laser outputter 1 and changes the width and length of the laser beam into a desired size. The laser outputter 1 can generate pulsed laser light, and one of various kinds of laser light such as a gas laser, a solid laser, etc. can be used.

[0039] The first beam module 10 constituting the optical system can be disposed on a traveling path of the laser beam output from the laser outputter 1, and can include a support rod 14 and a beam blocking module 13 disposed on the support rod 14. The support rod 14 can be configured such that it is formed of a transparent material or can have a slit formed in the center so that the laser beam can pass therethrough without loss, and supports the beam blocking module 13 in a movable manner. Two beam blocking modules 13 can be disposed in pairs on one side of the support rod 14. The distance between the two beam blocking modules 13 can be adjusted, and by adjusting the distance, the length of the laser beam can be adjusted. That is, the cross-sectional size of the laser beam is controlled. The beam blocking module 13 can have a heat dissipation structure, whereby heat generated by the blocked laser beam can be dissipated in an air-cooled manner. The heat dissipation structure of the beam blocking module 13 will be described in detail in Figure 4 to Figure 6 later. On the other hand, the support rod 14 is an optional configuration, and a support structure 15 that independently supports the beam blocking module 13 can be used instead of the support rod 14 to independently control the positions of the beam blocking modules 13. The support rod 14 and the support structure 15 are only two examples of a support body of the beam blocking module 13, and various different structures of the support body can be used.

[0040] ​​The reflector 20 is a component that reflects the laser beam that has passed through the first beam module 10 to change its direction of travel toward the projection lens 30.

[0041] The projection lens 30 is a component used to concentrate the laser beam to increase energy density. It may include multiple lenses 31, 32, 33, 34, and 35. All lenses 31, 32, 33, 34, and 35 can be convex lenses, or the uppermost lens 31 and the lowermost lens 35 can be spherical lenses. Figure 2 As shown, the laser beam can pass through the projection lens 30 while the beam width narrows and converges into a line at a predetermined focal distance.

[0042] The second beam module 40 can be configured on the path of the laser beam passing through the projection lens 30, and can include a support rod 44 and a pair of beam blocking modules 43 disposed on the support rod 44. The support rod 44 can be constructed of a transparent material or have a centrally formed slit to allow the laser beam to pass through without loss, and movably support the beam blocking modules 43. Two beam blocking modules 43 can be arranged in pairs on one side of the support rod 44. The distance between the two beam blocking modules 43 is adjustable, and by adjusting this distance, the length of the laser beam can be adjusted, i.e., the cross-sectional size of the laser beam can be controlled. The beam blocking module 43 can have a heat dissipation structure, thereby dissipating the heat generated by the blocked laser beam in an air-like manner. The heat dissipation structure of the beam blocking module 43 will be described with reference to... Figure 4 to Figure 6 This will be explained in detail later. On the other hand, the support rod 44 is an optional configuration, and the position of the beam blocking module 43 can also be independently controlled by a support structure 45 that independently supports the beam blocking module 43, instead of the support rod 44. The support rod 44 and the support structure 45 are merely two examples of supports for the beam blocking module 43, and various support structures can be used.

[0043] The second beam module 40 can be controlled in conjunction with the first beam module 10. When the laser beam that has passed through the first beam module 10 passes through the reflector 20 and the projection lens 30 and then passes through the second beam module 40, the distance and position between the two beam blocking modules 43 can be controlled so that the real beam (the laser beam except for the part that is diffused and broadened due to diffraction (hereinafter referred to as the "diffracted beam")) can pass through completely while the diffracted beam is blocked.

[0044] The beam cutter 50 can be configured on the path of the laser beam passing through the second beam module 40, and can include a support rod 54 and a pair of beam blocking modules 53 disposed on the support rod 54. The support rod 54 can be formed of a transparent material or have a centrally formed slit to allow the laser beam to pass through without loss, and movably support the beam blocking modules 53. Two beam blocking modules 53 can be arranged in pairs on one side of the support rod 54. The distance between the two beam blocking modules 53 is adjustable, and by adjusting this distance, the length of the laser beam can be adjusted, i.e., the cross-sectional size of the laser beam can be controlled. The beam blocking module 53 can have a portion 531 formed of SUS (steel usestainless steel) and a portion 532 formed of a material with high specific heat, such as quartz. The portion 532 formed of the material with high specific heat can be disposed in the area irradiating the laser beam. Related details will be referred to... Figure 7 and Figure 8 This will be explained in detail later. On the other hand, the support rod 54 is an optional configuration; alternatively, a support structure 55 that independently supports the beam blocking module 53 can be used to independently control the position of the beam blocking module 53. The support rod 54 and the support structure 55 are merely two examples of supports for the beam blocking module 53; various support structures can be used.

[0045] The beam cutter 50 can be controlled in conjunction with the first beam module 10 and the second beam module 40. When the laser beam passing through the second beam module 40 passes through the beam cutter 50, the distance between the two beam blocking modules 53 can be controlled so that the real beam passes through completely while the diffracted beam is blocked. Here, the lengths of the laser beams passing through the first beam module 10, the second beam module 40, and the beam cutter 50 can be the same. That is, the cross-sectional lengths of the laser beams passing through the first beam module 10, the second beam module 40, and the beam cutter 50 can be the same.

[0046] In this type of laser irradiation device, such as Figure 3As shown, for the laser beam output by laser outputter 1, the first beam module 10 performs a first cut to adjust the beam length, and the second beam module 40 performs a second cut to the diffracted beam generated by diffraction as the laser beam travels, thus allowing only the real beam to travel. The beam cutter 50 can perform a third cut to the diffracted beam generated by diffraction as the real beam passes through the second beam module 40, thus again allowing only the real beam to travel towards the target. Through this process, the first beam module 10 can absorb the laser beam with 100% of the energy of the output laser by blocking it, the second beam module 40 can absorb the diffracted light with 20% of the energy of the output laser by blocking it, and the beam cutter 50 can absorb the diffracted light with 4% of the energy of the output laser by blocking it. Therefore, most of the energy of the blocked laser beam is blocked and absorbed by the first beam module 10 and the second beam module 40, and the energy of the laser beam blocked and absorbed by the beam cutter 50 is significantly reduced. This prevents heat generated by the beam cutter 50 located near the amorphous silicon film, thereby improving the uniformity of the polycrystalline silicon film polycrystalline by laser irradiation.

[0047] Figure 4 This is a front view (viewed from above) of the heat dissipation structure of the beam module used in an optical component according to an embodiment of the present invention. Figure 5 yes Figure 4 Left side view of the beam module. Figure 6 yes Figure 4 The lower side view of the beam module.

[0048] The beam blocking modules 13 and 43 of the first beam module 10 and the second beam module 40 described above are as follows: Figure 4 to Figure 6 As shown, it can have a heat dissipation structure. The beam blocking modules 13 and 43 may include a substrate 131 and a plurality of protruding walls 132 formed side by side on the substrate 131. The plurality of protruding walls 132 are formed with unevenness to expand the surface area, or they may be replaced by a plurality of protruding pillars or other protruding structures.

[0049] When configuring the first beam module 10 and the second beam module 40, they can be configured to irradiate a laser beam toward the surface on which the plurality of protruding walls 132 are formed. The laser beam irradiating the plurality of protruding walls 132 is absorbed by the plurality of protruding walls 132 and generates heat, which can be dissipated by propagation through the plurality of protruding walls 132. As described above, the heat generated during the laser beam cutting process is quickly dissipated by the heat dissipation structure, thereby preventing the laser crystallization device from being affected by the heat generated at this time or preventing non-uniformity from occurring in the polycrystalline silicon film.

[0050] Figure 7This is a partial cross-sectional view of a beam cutter used in an optical assembly according to an embodiment of the present invention. Figure 8 This is a schematic diagram illustrating the function of a beam cutter used in an optical component according to an embodiment of the present invention.

[0051] The beam blocking module 53 of the beam cutter 50 described above is as follows: Figure 7 As shown, it may include: portion 531, forming a support structure; and portion 532, blocking the laser beam. The portion 531 forming the support structure may be made of a durable material such as SUS, and the portion 532 blocking the laser beam may be made of a material with high specific heat and low thermal conductivity, such as quartz, so that even if heat is generated by the laser beam, its propagation to the surrounding area can be suppressed.

[0052] The following table compares the material properties of SUS forming portion 531 and quartz forming portion 532.

[0053] Differentiation SUS (Serial Number) Quartz Density (g / cm 3 )]]> 8.02 2.02 Specific heat (J / Kg-K) 13 749 Transmittance (%) 0％ 1％↓ Melting point (°C) 1399 1170

[0054] If this beam cutter 50 is positioned at the final output end of the laser beam, then as... Figure 8 As shown, the beam-blocking portion 532, made of a material with high specific heat and low thermal conductivity, blocks the diffracted beam, allowing only the real beam to pass through the sealbox 60 and irradiate the target object. The sealbox 60 is configured to maintain the portion irradiated by the laser in a predetermined gaseous environment, thus sealing the predetermined gas.

[0055] As described above, the diffracted beam blocked by the portion 532 has only 4% of the energy of the original output, resulting in less heat. Furthermore, this heat is absorbed by a material with high specific heat and low thermal conductivity, thus preventing the ambient temperature from rising.

[0056] The embodiments of the present invention have been described in detail above, but the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art using the basic concepts of the present invention as defined in the claims also fall within the scope of the present invention.

Claims

1. A laser irradiation device, comprising: Laser output device; The first beam module is configured on the path of the laser beam output by the laser output device and blocks both ends of the laser beam to control the length of the laser beam; The projection lens focuses the laser beam that has passed through the first beam module; A second beam module is configured on the travel path of the laser beam passing through the projection lens, and controls the length of the laser beam passing through the projection lens; and A beam cutter is positioned along the path of the laser beam that has passed through the second beam module, and controls the length of the laser beam that has passed through the second beam module. The laser beam that passes through the first beam module passes through the second beam module, and the diffracted beam is blocked by the second beam module.

2. The laser irradiation device according to claim 1, wherein, The laser beams passing through the first beam module, the second beam module, and the beam cutter have the same length.

3. The laser irradiation device according to claim 1, wherein, The laser beam that passes through the second beam module passes through the beam cutter, and the diffracted beam is blocked by the beam cutter.

4. The laser irradiation device according to claim 1, wherein, The first beam module and the second beam module each include a support body and a pair of beam blocking modules supported by the support body.

5. The laser irradiation device according to claim 4, wherein, The beam blocking module of the first beam module has a heat dissipation structure.

6. The laser irradiation device 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 arranged side by side.

7. The laser irradiation device according to claim 5, wherein, The heat dissipation structure of the beam blocking module of the first beam module is disposed on the surface of the side irradiating the laser beam.

8. The laser irradiation device according to claim 4, wherein, The beam blocking module of the second beam module has a heat dissipation structure.

9. The laser irradiation device 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 arranged side by side.

10. The laser irradiation apparatus according to claim 8, wherein, The heat dissipation structure of the beam blocking module of the second beam module is disposed on the surface of the side irradiating the laser beam.

11. The laser irradiation device according to claim 4, wherein, The distance between the pair of beam blocking modules is adjustable.

12. The laser irradiation device 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 device according to claim 12, wherein, The beam blocking module of the beam cutter includes a support structure and a laser beam blocking section, wherein the laser beam blocking section is formed of a material with a specific heat greater than that of the support structure.

14. The laser irradiation apparatus according to claim 13, wherein, The supporting structure is made of stainless steel, and the laser beam blocking part is made 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: A reflector reflects the laser beam that has passed through the first beam module and directs it toward the projection lens.

17. An optical system comprising: The first beam module controls the cross-sectional size of the laser beam; The projection lens focuses the laser beam that has passed through the first beam module; The second beam module is configured on the travel 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. A beam cutter is positioned along the 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. The laser beams passing through the first beam module, the second beam module, and the beam cutter have the same cross-sectional length. The laser beam that passes through the first beam module passes through the second beam module, and the diffracted beam is blocked by the second beam module.

18. The optical system according to 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 heat dissipation structures. The beam blocking module of the beam cutter includes a support structure and a laser beam blocking section, wherein the laser beam blocking section is formed of a material with a specific heat greater than that of the support structure.

19. The optical system of claim 18, further comprising: A reflector reflects the laser beam that has passed through the first beam module and directs it toward the projection lens.

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