Laser irradiation device and laser irradiation method

Abstract

A laser irradiation apparatus and a laser irradiation method are disclosed. The laser irradiation apparatus can include a laser light source generating a laser beam; a first lens through which the laser beam generated in the laser light source passes; a first scanner reflecting the laser beam passing through the first lens and changing a direction of the laser beam; a second scanner reflecting the laser beam deflected in the first scanner and changing a direction of the laser beam; a plurality of second lenses through which the laser beam deflected in the second scanner passes and which vibrate in a direction; and an optical element through which the laser beam passing through the plurality of second lenses passes and which corrects an incident angle of the laser beam on a substrate. Thus, crystal mottle generated when an amorphous semiconductor film is crystallized can be reduced, and a high-resolution display panel can be manufactured.

Description

Technical Field

[0001] This invention relates to a laser irradiation apparatus and a laser irradiation method, and more specifically to a laser irradiation apparatus and a laser irradiation method for polycrystalline silicon manufacturing. Background Technology

[0002] Thin-film transistors (TFTs) are fabricated on substrates and applied to active-matrix display devices. Compared to TFTs using amorphous semiconductor films, TFTs using polycrystalline semiconductor films have the advantages of high electron mobility and high-speed operation. To this end, a technique is being researched to crystallize amorphous semiconductor films formed on insulating substrates such as glass to form polycrystalline semiconductor films with crystalline structures.

[0003] As a method for crystallizing amorphous semiconductor films, furnace annealing, rapid annealing, or laser annealing are being explored, and combinations of these methods are also being investigated. For example, laser annealing has the advantage of imparting high energy only to the crystallization region without excessively altering the substrate temperature.

[0004] Typically, pulsed excimer lasers are used as the laser beam for laser annealing. As the laser usage time increases, the oscillation efficiency of the pulse decreases, which may lead to non-uniformity of oscillation energy and reduce the uniformity of the beam shape.

[0005] Previously, crystallization processes were performed by scanning an amorphous silicon layer on a substrate with laser beams in the form of lines at a certain pitch.

[0006] However, the lines beam typically utilizes a gas tube to employ a gas laser, but the manufacturing and maintenance costs of such equipment are quite high.

[0007] In addition, the size and shape of the crystals vary depending on the laser irradiation method, and various efforts have been made to obtain uniformly arranged polygonal crystals. Summary of the Invention

[0008] One object of the present invention is to provide a laser irradiation device in which multiple second lenses vibrate in the scanning direction and optical elements are arranged below the multiple second lenses in order to reduce crystallization patterns.

[0009] Another object of the present invention is to provide a laser irradiation method using the laser irradiation device.

[0010] However, the purpose of this invention is not limited to such an purpose, and various extensions can be made without departing from the concept and scope of this invention.

[0011] A laser irradiation apparatus according to one embodiment of the present invention, for achieving the above-described object of the invention, may include: a laser source for emitting a laser beam; a first lens through which the laser beam emitted from the laser source passes; a first scanner for reflecting the laser beam passing through the first lens and changing the direction of the laser beam; a second scanner for reflecting the laser beam deflected in the first scanner and changing the direction of the laser beam; a plurality of second lenses through which the laser beam deflected in the second scanner passes and vibrates in one direction; and optical elements through which the laser beam passing through the plurality of second lenses passes and corrects the incident angle of the laser beam incident on the substrate.

[0012] In one embodiment, the plurality of second lenses may change the incident position of the laser beam that is deflected in the second scanner.

[0013] In one embodiment, the optical element may vibrate in a direction perpendicular to the vibration direction of the plurality of second lenses.

[0014] In one embodiment, the vibration period of the plurality of second lenses may be the same as the vibration period of the optical element.

[0015] In one embodiment, it could be the vibration of at least one of the plurality of second lenses.

[0016] In one embodiment, the first scanner may be a vibrating galvano mirror, and the second scanner may be a rotatable polygon mirror.

[0017] In one embodiment, the optical element may also have two prisms of the same shape attached together.

[0018] In one embodiment, each of the prisms may be a hexahedron, and the optical element may be a symmetrical shape in which one face of each of the prisms is pasted onto the other.

[0019] In one embodiment, the optical element may be disposed below the plurality of second lenses.

[0020] In one embodiment, the optical element may be formed of quartz.

[0021] A laser irradiation method according to an embodiment of the present invention, for achieving the above-described objectives, may include: emitting a laser beam from a laser source; the laser beam emitted from the laser source incident on a first lens; the laser beam passing through the first lens being reflected by a first scanner and having its direction changed; the laser beam deflected by the first scanner being reflected by a second scanner and having its direction changed; the laser beam deflected by the second scanner incident on a plurality of second lenses vibrating in one direction; the laser beam passing through the plurality of second lenses incident on an optical element and having its incident angle corrected; and the laser beam passing through the optical element irradiating a substrate for scanning.

[0022] In one embodiment, when the laser beam passing through the optical element irradiates the substrate, the scanning position moves in the same direction as the vibration direction of the plurality of second lenses.

[0023] In one embodiment, the plurality of second lenses may change the incident position of the laser beam that is deflected in the second scanner.

[0024] In one embodiment, the optical element may vibrate in a direction perpendicular to the vibration direction of the plurality of second lenses.

[0025] In one embodiment, the vibration period of the plurality of second lenses may be the same as the vibration period of the optical element.

[0026] In one embodiment, the first scanner may be a vibrating galvano mirror, and the second scanner may be a rotatable polygon mirror.

[0027] In one embodiment, the optical element may be two prisms of the same shape pasted together.

[0028] In one embodiment, each of the prisms may be a hexahedron, and the optical element may be a symmetrical shape in which one face of each of the prisms is pasted onto the other.

[0029] In one embodiment, the optical element may be disposed below the plurality of second lenses.

[0030] In one embodiment, the optical element may be formed of quartz.

[0031] (Invention Effects)

[0032] In the laser irradiation apparatus and laser irradiation method according to embodiments of the present invention, in order to correct the different incident angles on the substrate due to the vibration of the plurality of second lenses, optical elements can be arranged below the plurality of second lenses. This reduces crystallization patterns generated during the crystallization of amorphous semiconductor films, enabling the manufacture of high-resolution display panels.

[0033] However, the effects of the present invention are not limited to those described, and various extensions can be made without departing from the concept and scope of the present invention. Attached Figure Description

[0034] Figure 1 as well as Figure 2 This is a diagram illustrating a laser irradiation apparatus according to an embodiment of the present invention.

[0035] Figure 3 This is a diagram showing a substrate subjected to a laser irradiation method according to an embodiment of the present invention.

[0036] Figure 4 It is shown that it includes Figure 1 as well as Figure 2 A diagram of the optical components in a laser irradiation device.

[0037] Figure 5 This shows the view in the z-direction. Figure 4 A diagram showing the shape of the optical element.

[0038] Figure 6 This shows the view in the y-direction. Figure 4 A diagram showing the shape of the optical element.

[0039] Figure 7 This shows the view in the x-direction. Figure 4 A diagram showing the shape of the optical element.

[0040] Figure 8 The diagram shows the first to fourth lengths, substrate incident angle, lens incident angle, divergence angle, etc. of the laser irradiation method according to the present invention.

[0041] Figure 9 It is shown that it includes Figures 4 to 7 A diagram showing the angle, length, and thickness of the optical elements in a laser irradiation device.

[0042] (Explanation of reference numerals in the attached diagram)

[0043] 100: Laser irradiation device

[0044] 10: Substrate

[0045] 20: Optical components

[0046] 30a: First lens

[0047] 30b: Multiple second lenses

[0048] 40a: First Scanner

[0049] 40b: Second Scanner

[0050] 50: Laser source Detailed Implementation

[0051] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and repeated descriptions of the same components are omitted.

[0052] Figure 1 as well as Figure 2 This is a diagram illustrating a laser irradiation apparatus according to an embodiment of the present invention.

[0053] Reference Figure 1 as well as Figure 2 The laser irradiation device 100 may include an optical element 20, a first lens 30a, a plurality of second lenses 30b, a laser source 50, a first scanner 40a, and a second scanner 40b. The laser irradiation device 100 can irradiate the surface of the substrate 10 with a spot beam laser in a scanning manner.

[0054] The laser source 50 can be a laser oscillator. The laser oscillator can be, for example, a continuous-wave laser oscillator or a pulsed-wave laser oscillator with a repetition frequency of about 30 MHz or higher. For example, the laser oscillator can emit a laser beam with a wavelength of 532 nm or about 355 nm with a repetition frequency of about 30 MHz. For example, when the laser oscillator is a solid-state laser such as an Nd:YAG laser (1064 nm), the approximately 532 nm wavelength can be a second harmonic wave, and the approximately 355 nm wavelength can be a third harmonic wave.

[0055] The laser oscillator can be a known continuously oscillating solid-state laser. Examples of such solid-state lasers include YAG lasers, YVO4 lasers, YLF lasers, YAlO3 lasers, Y2O3 lasers, glass lasers, ruby ​​lasers, alexandrite lasers, Ti:sapphire lasers, etc.

[0056] A laser beam emitted from laser source 50 can be incident on first lens 30a. First lens 30a can be an optical system for focusing light, such as a spherical lens or a Fresnel lens. The laser beam passing through first lens 30a can be reflected by first scanner 40a.

[0057] The first scanner 40a can be a galvano mirror. The angle of reflection of the laser beam can be changed by the vibration of the first scanner 40a. That is, the first scanner 40a can function as a scanner that changes the direction of the reflected laser beam. In one embodiment, when the laser beam vibrates, the first scanner 40a can maintain the angle of incidence on the substrate 10.

[0058] The laser beam deflected by the first scanner 40a can be reflected by the second scanner 40b. The second scanner 40b can be a polygon mirror. The angle of reflection of the laser beam can be changed by rotating the second scanner 40b. That is, the second scanner 40b can function as a scanner that changes the direction of the reflected laser beam. The second scanner 40b can be made of glass or metal.

[0059] The laser beam, deflected by the second scanner 40b, can pass through a plurality of second lenses 30b that vibrate in one direction. This direction can refer to the scan direction. The scan direction can be defined as the direction of the laser beam's illumination position on the substrate 10. The plurality of second lenses 30b can be fθ lenses. The fθ lenses can focus the laser beam so that it is always focused on the irradiated object, i.e., the substrate 10. At least one of the plurality of second lenses 30b can vibrate in the scan direction. Selectively, at least one of the plurality of second lenses 30b can vibrate in a direction perpendicular to the scan direction. In one embodiment, the plurality of second lenses 30b vibrating in the scan direction can change the incident position of the laser beam deflected in the second scanner 40b on the substrate 10.

[0060] The laser beam passing through the plurality of second lenses 30b can pass through the optical element 20. The optical element 20 may include a first region 21 and a second region 22. The first region 21 may be defined as a portion that is thicker on the left and thinner on the right relative to the x-direction, and the second region 22 may be defined as a portion that is thinner on the left and thicker on the right relative to the x-direction. The optical element 20 may be disposed below the plurality of second lenses 30b. When the plurality of second lenses 30b vibrate in the scan direction, the angle of incidence on the substrate 10 when the laser beam is incident on the substrate 10 may be tilted. When the angle of incidence on the substrate 10 is tilted, the optical element 20 vibrates in a direction perpendicular to the scan direction, thereby correcting the angle of incidence on the substrate 10. The vibration periods of the plurality of second lenses 30b and the optical element 20 may be the same. The optical element 20 may be defined as an angle of incidence correction plate. In one embodiment, the optical element 20 may be formed of quartz. However, the invention is not limited thereto, and the optical element 20 may be formed of other materials.

[0061] In one embodiment, when the plurality of second lenses 30b move in a direction opposite to the x-direction, the angle of incidence on the substrate 10 can be tilted counterclockwise. In this case, the angle of incidence on the substrate 10 can be corrected when the laser beam passes through the first region 21 of the optical element 20. Alternatively, when the plurality of second lenses 30b move in the x-direction, the angle of incidence on the substrate 10 can be tilted clockwise. In this case, the angle of incidence on the substrate 10 can be corrected when the laser beam passes through the second region 22 of the optical element 20. Alternatively, when the plurality of second lenses 30b are centered with the x-direction as a reference, the laser beam can pass between the first region 21 and the second region 22 of the optical element 20 to maintain the angle of incidence on the substrate 10.

[0062] Figure 3 This is a diagram showing a substrate subjected to a laser irradiation method according to an embodiment of the present invention.

[0063] Reference Figure 3 The entire substrate 10 can be laser-processed by scanning the substrate 10 multiple times with a spot beam laser in the x direction perpendicular to the y direction.

[0064] The laser irradiation method utilizes a point-beam laser to irradiate the surface of the substrate 10, causing the irradiated area of ​​the laser beam to move along the x-direction. That is, the laser beam can be scanned to irradiate a first portion 11 that has a width in the y-direction and a length in the x-direction.

[0065] After scanning the first portion 11, the substrate 10 can be moved a certain distance in the y-direction, which is perpendicular to the scan direction. After moving the substrate 10 a certain distance, the spot laser beam can be used to scan the second portion 12, which has a width in the y-direction and a length in the x-direction.

[0066] After the second part 12 is scanned, the substrate 10 can be moved a certain distance in the y-direction, which is perpendicular to the scan direction. After the substrate 10 is moved, the spot laser beam can be used to scan the third part 13, which has a width in the y-direction and a length in the x-direction.

[0067] By repeating the scan as described above, the parallelism of the scan (san) over the entire substrate 10 and the angle of incidence on the substrate 10 can be maintained, while forming a crystalline region.

[0068] The substrate 10 can be any one of LTPS (Low Temperature Poly-Si) substrate, glass substrate, plastic substrate, and stainless steel (SUS) substrate. Alternatively, an amorphous silicon layer can be formed on the substrate 10, which crystallizes under laser irradiation to form polysilicon. That is, crystallization can be achieved through near-complete melting of the amorphous silicon by the irradiated laser beam.

[0069] Figure 4 It is shown that it includes Figure 1 as well as Figure 2 A diagram of the optical components in a laser irradiation device. Figure 5 This shows the view in the z-direction. Figure 4 A diagram showing the shape of the optical element. Figure 6 This shows the view in the y-direction. Figure 4 A diagram showing the shape of the optical element. Figure 7 This shows the view in the x-direction. Figure 4 A diagram showing the shape of the optical element.

[0070] Reference Figure 4Optical element 20 can be two prisms of the same shape glued together. In one embodiment, each prism can be a hexahedron. For example, the hexahedron can have different heights in the z-direction, and when viewed in the y-direction, optical element 20 can be in a configuration where the faces with the same height are glued together. When viewed in the y-direction, optical element 20 can be symmetrical with respect to the faces with the same height.

[0071] Specifically, refer to Figure 5 The optical element 20, viewed in the z-direction, can be a combination of two rectangles of the same size joined together. (Refer to...) Figure 6 The shape of the optical element 20, when viewed in the y-direction, can be a shape with a centrally symmetrical form. (Refer to...) Figure 7 The optical element 20, when viewed in the x direction, can be a shape with a centrally symmetrical form.

[0072] Reference Figure 4 as well as Figure 6 The optical element 20 can generate a length difference in the z direction along the x direction.

[0073] Reference Figure 4 as well as Figure 7 The length difference in the z-direction can be maximized at both ends in the y-direction.

[0074] Figure 8 The diagram shows the first to fourth lengths, substrate incident angle, lens incident angle, divergence angle, etc. of the laser irradiation method according to the present invention.

[0075] exist Figure 8 In the diagram, for substrate 10, the substrate incident angle θ1, lens incident angle θ2, divergence angle θ3, first length 60, second length 70, third length 80, and fourth length 90 of the laser beam emitted from laser source 50 are shown.

[0076] Reference Figure 1 , Figure 2 as well as Figure 8 The incident angle θ1 on the substrate can be defined as the angle formed between the laser beam and the substrate 10 when the laser beam passes through the optical element 20 and is incident on the substrate 10. The incident angle θ2 on the lens can be defined as the angle formed between the laser beam and the multiple second lenses 30b when the laser beam is deflected in the second scanner 40b and is incident on the multiple second lenses 30b. The divergence angle θ3 can be defined as the angle between part ① and part ② when the laser beam deflected and emitted in the second scanner 40b is incident on the multiple second lenses 30b.

[0077] The first length 60 can be defined as the length between the plurality of second lenses 30b and the substrate 10. The second length 70 can be defined as... Figure 3The diagram shows a scanning length. The third length 80 can be defined as the width of the position change of the laser beam irradiating the substrate 10. The fourth length 90 can be defined as the position change width of the second scanner 40b.

[0078] In one embodiment, the divergence angle θ3 of the laser beam deflected in the second scanner 40b may be approximately 30 degrees, the second length 70 approximately 600 mm, and the first length 60 approximately 500 mm. In this case, the third length 80 may be approximately -0.5 mm to approximately 0.5 mm, and the change in the substrate incident angle θ1 may be approximately -0.057 degrees to approximately 0.057 degrees. To make the change in the substrate incident angle θ1 approximately -0.057 degrees to approximately 0.057 degrees, the position of the second scanner 40b may be moved such that the fourth length 90 is approximately 2.4 mm, thereby changing the lens incident angle θ2 by approximately 0.2 degrees. Alternatively, if the position of the second scanner 40b is moved by moving a plurality of second lenses 30b by approximately 2.4 mm instead of moving the position of the second scanner 40b, the change in the lens incident angle θ2 may be approximately 0.2 degrees.

[0079] As described above, in order to modify the changing incident angle θ1 of the substrate, the optical element 20 described below may be required.

[0080] Figure 9 It is shown that it includes Figures 4 to 7 A diagram showing the angle, length, and thickness of the optical elements in a laser irradiation device.

[0081] exist Figure 9 The image shows the angle θ4 of the optical element 20, the length of the long piece 110, and the thickness difference 120.

[0082] Reference Figure 9 A thickness difference of 120 can be defined as... Figure 5 The height difference between the two ends of a prism as observed in the y-direction of the optical element 20. The length 110 of the long strip can be defined as... Figure 5 The length of a prism in the x-direction of an optical element. Angle θ₄ can be defined as tan... -1 (Thickness difference 120 / Long piece length 110).

[0083] In one embodiment, such as Figure 8As shown, when the divergence angle θ3 is 30 degrees, the first length 60 is approximately 500 mm, and the second length 70 is approximately 600 mm, the third length 80 can be approximately -0.5 mm to approximately 0.5 mm, achieved by multiple second lenses 30b vibrating in the scan direction. As described above, when the third length 80 is approximately -0.5 mm to approximately 0.5 mm, the change in the substrate incident angle θ1 can be approximately -0.057 degrees to approximately 0.057 degrees. In this case, to modify the change in the substrate incident angle θ1 from approximately -0.057 degrees to approximately 0.057 degrees to 0, an optical element 20 can be configured.

[0084] When the optical element 20 is configured, in order to modify the change in the substrate incident angle θ1 from approximately -0.057 degrees to approximately 0.057 degrees, the thickness difference 120 of the optical element 20 can be approximately 1.14 mm, the elongated length 110 of the optical element 20 can be approximately 620 mm, and the angle θ4 of the optical element 20 can be 0.106 degrees. However, the elongated length 110 and the thickness difference 120 are not limited to these; they can have various values ​​as long as the angle θ4 is 0.106 degrees. Thus, crystal patterns generated in the display panel can be reduced by correcting the incident angle of the laser beam irradiating the substrate.

[0085] While the foregoing description has been made with reference to exemplary embodiments of the invention, those skilled in the art will understand that various modifications and alterations can be made to the invention without departing from the concept and scope of the invention as set forth in the claims.

[0086] (Industry availability)

[0087] This invention is applicable to organic light-emitting display devices and various electronic devices including them. For example, it is applicable to mobile phones, smartphones, video phones, smart tablets, smartwatches, tablet computers, vehicle navigation systems, televisions, computer monitors, laptops, head-mounted displays, etc.

Claims

1. A laser irradiation device, characterized in that, include: Laser source, emitting laser beam; A first lens through which the laser beam emitted from the laser source passes; The first scanner reflects the laser beam passing through the first lens and changes the direction of the laser beam; The second scanner reflects the laser beam that is deflected in the first scanner and changes the direction of the laser beam; Multiple second lenses are provided for the laser beam, which is deflected in the second scanner, to pass through and vibrate in one direction; as well as Optical elements for through which the laser beam passing through the plurality of second lenses passes, and for correcting the incident angle of the laser beam onto the incident substrate. The optical element vibrates in a direction perpendicular to the vibration direction of the plurality of second lenses, and the perpendicular direction is not parallel to the top surface of the substrate.

2. The laser irradiation device according to claim 1, characterized in that, The plurality of second lenses alter the incident position of the laser beam that is deflected in the second scanner.

3. The laser irradiation device according to claim 1, characterized in that, The vibration period of the plurality of second lenses is the same as the vibration period of the optical element.

4. The laser irradiation device according to claim 1, characterized in that, At least one of the plurality of second lenses vibrates.

5. The laser irradiation device according to claim 1, characterized in that, The first scanner is a vibrating current mirror. The second scanner is a rotatable polyhedral mirror.

6. The laser irradiation device according to claim 1, characterized in that, The optical element has the shape of two identical prisms attached together.

7. The laser irradiation device according to claim 6, characterized in that, Each of the prisms is a hexahedron. The optical element has a symmetrical shape in which one face of each prism is attached to the other.

8. The laser irradiation device according to claim 1, characterized in that, The optical element is positioned below the plurality of second lenses.

9. The laser irradiation device according to claim 1, characterized in that, The optical element is made of quartz.

10. A laser irradiation method, characterized in that, include: The steps of emitting a laser beam from a laser source; The step of the laser beam emitted from the laser source entering the first lens; The steps of the laser beam passing through the first lens being reflected by the first scanner and changing the direction of the laser beam; The step of the laser beam, which is deflected by the first scanner, being reflected by the second scanner and changing the direction of the laser beam; The step of the laser beam, which is deflected by the second scanner, being incident on a plurality of second lenses that vibrate in one direction; The steps of the laser beam passing through the plurality of second lenses and incident on the optical element and correcting the incident angle; as well as The step of scanning is to illuminate the substrate with the laser beam that passes through the optical element. The optical element vibrates in a direction perpendicular to the vibration direction of the plurality of second lenses, and the perpendicular direction is not parallel to the top surface of the substrate.

11. The laser irradiation method according to claim 10, characterized in that, When the laser beam passing through the optical element irradiates the substrate, the scanning position moves in the same direction as the vibration direction of the plurality of second lenses.

12. The laser irradiation method according to claim 10, characterized in that, The plurality of second lenses alter the incident position of the laser beam that is deflected in the second scanner.

13. The laser irradiation method according to claim 10, characterized in that, The vibration period of the plurality of second lenses is the same as the vibration period of the optical element.

14. The laser irradiation method according to claim 10, characterized in that, The first scanner is a vibrating current mirror. The second scanner is a rotatable polyhedral mirror.

15. The laser irradiation method according to claim 10, characterized in that, The optical element has the shape of two identical prisms attached together.

16. The laser irradiation method according to claim 15, characterized in that, Each of the prisms is a hexahedron. The optical element has a symmetrical shape in which one face of each prism is attached to the other.

17. The laser irradiation method according to claim 10, characterized in that, The optical element is positioned below the plurality of second lenses.

18. The laser irradiation method according to claim 10, characterized in that, The optical element is made of quartz.

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