Laser machining device

Abstract

A laser processing device is provided. The laser processing device includes a laser light source, a width adjustment unit for adjusting the width of a laser beam emitted from the laser light source, and a scanner unit for adjusting the direction of irradiation of a laser beam that has passed through the width adjustment unit. The width adjustment unit includes a first width adjustment unit and a second width adjustment unit arranged in overlap with the direction of travel of the laser beam, wherein the focal length of the first width adjustment unit and the second width adjustment unit is 20,000 mm or more.

Description

Technology Field

[0001] The present invention relates to a laser processing device. Background Technology

[0002] A laser processing device is a device that uses a laser beam to perform processing such as cutting, pattern formation, and welding of materials. The laser beam used in laser processing is characterized by strong directivity and high density. In particular, high-output lasers do not affect the surroundings and enable precision processing, making them suitable for the processing of display panels.

[0003] A laser processing device may include a laser light source that outputs a laser beam, a laser irradiation unit comprising a scanner that controls the irradiation position of the output laser beam and an F / Theta lens that focuses the laser beam at the determined irradiation position, and a stage on which a processing target is aligned.

[0004] In a laser processing device, the scanning line of the laser beam is determined by the scanner. The problem to be solved

[0005] The problem that the present invention aims to solve is to improve the reliability of a laser processing device by preventing the phenomenon in which the area irradiated by the laser beam varies depending on the processing path of the laser processing device when the cross-section of the laser beam is elliptical due to a simple structure.

[0006] Another problem that the present invention aims to solve is to provide a laser processing method that prevents defects caused by differences in the irradiation area of ​​the laser beam by adjusting a laser beam with an elliptical cross-section into a laser beam with a circular cross-section using a simple method.

[0007] The problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0008] A laser processing device according to one embodiment for solving the above problem comprises a laser light source, a width adjustment unit for adjusting the width of a laser beam emitted from the laser light source, and a scanner unit for adjusting the irradiation direction of a laser beam that has passed through the width adjustment unit, wherein the width adjustment unit comprises a first width adjustment unit and a second width adjustment unit arranged in overlap with the direction of travel of the laser beam, and the focal length of the first width adjustment unit and the second width adjustment unit is 20,000 mm.

[0009] The first width adjustment unit and the second width adjustment unit may have the same shape and be made of the same material.

[0010] It may further include an F-theta lens that focuses the laser beam passing through the scanner to the area to be processed.

[0011] The first width adjustment unit and the second width adjustment unit each include a reference line, and the first width adjustment unit and the second width adjustment unit can adjust the cross-section of the incident laser beam in a direction perpendicular to the reference line.

[0012] The first width adjustment unit and the second width adjustment unit each include a convex surface and a concave surface, and the curvatures of the convex surface and the concave surface may be different from each other.

[0013] The convex surfaces of the first width adjustment unit and the second width adjustment unit are both arranged in a direction in which a laser beam is incident on the width adjustment unit, and the laser beam passes through the first width adjustment unit and the second width adjustment unit and can contract in a direction perpendicular to the reference line of the first width adjustment unit and the reference line of the second width adjustment unit.

[0014] The radius of curvature of the convex surface is 23 to 24 mm, the radius of curvature of the concave surface is 19 mm to 21 mm, and the thickness of the first width adjustment unit and the second width adjustment unit may be 9 mm to 11 mm.

[0015] The width adjustment unit includes an opening, and can adjust the arrangement of the first width adjustment unit and the second width adjustment unit through the opening.

[0016] The laser beam passes through the first width adjustment unit and the second width adjustment unit and contracts in a direction perpendicular to the reference line of the first width adjustment unit and the reference line of the second width adjustment unit, and the cross-section of the laser beam incident on the width adjustment unit can be adjusted by adjusting the arrangement of the first width adjustment unit and the angle between the reference line of the first width adjustment unit and the reference line of the second width adjustment unit.

[0017] A beam expander that increases the overall diameter of the laser beam may be further included between the laser light source and the width adjustment unit.

[0018] The cross-sectional area in the direction perpendicular to the direction of travel of the laser beam emitted from the beam expander may be smaller than the cross-sectional area of ​​the first width adjustment unit and the second width adjustment unit.

[0019] The first width adjustment unit and the second width adjustment unit may have different shapes.

[0020] The first width adjustment unit and the second width adjustment unit each include a convex surface and a concave surface, and the curvatures of the convex surface and the concave surface may be different from each other.

[0021] The convex surface of the first width adjustment unit is positioned in a direction in which the laser beam is incident on the width adjustment unit, and the convex surface of the second width adjustment unit can be positioned in a direction in which the laser beam is emitted from the width adjustment unit.

[0022] The first width adjustment unit and the second width adjustment unit each include a reference line, and the first width adjustment unit and the second width adjustment unit can adjust the cross-section of an incident laser beam in a direction perpendicular to the reference line.

[0023] The first width adjustment unit can contract the cross-section of the laser beam passing through the first width adjustment unit in a direction perpendicular to the reference line of the first width adjustment unit, and the second width adjustment unit can expand the cross-section of the laser beam passing through the second width adjustment unit in a direction perpendicular to the reference line of the second width adjustment unit.

[0024] A laser processing method according to another embodiment for solving the above problem comprises the steps of measuring a cross-section of a laser beam, analyzing the cross-section of the laser beam to determine the direction and ratio of the major axis and the minor axis, and arranging the first width adjustment unit and the second width adjustment unit so as to overlap with the direction of propagation of the laser beam by adjusting the relative angle between the reference line of the first width adjustment unit and the second width adjustment unit and the major axis and the minor axis of the laser beam, taking into account the direction and ratio of the major axis and the minor axis of the laser beam.

[0025] After the step of arranging the first width adjustment unit and the second width adjustment unit, the method may further include the step of emitting the laser beam toward the first width adjustment unit and the second width adjustment unit to adjust the cross-section of the laser beam.

[0026] After the step of adjusting the cross-section of the laser beam, the method may further include a step of processing an object using the laser beam.

[0027] The method may further include the step of positioning the scanner unit so as to overlap with the direction of travel of the laser beam. Effects of the invention

[0028] According to the laser processing device and laser processing method of the embodiments, a laser beam with an elliptical cross-section can be adjusted into a laser beam with a circular cross-section. Accordingly, the phenomenon in which the area irradiated by the laser beam varies depending on the processing path of the laser processing device can be prevented.

[0029] The effects according to the embodiments are not limited to those exemplified above, and a wider variety of effects are included in this specification. Brief explanation of the drawing

[0030] FIG. 1 is a perspective view of a laser processing device according to one embodiment of the present invention. Figure 2 is a schematic side view of the width adjustment unit with the lid closed. Figure 3 is a schematic side view of the width adjustment unit with the lid open. Figure 4 is a schematic diagram illustrating the shape of a width adjustment unit. FIGS. 5 to 7 are schematic diagrams showing the shape of a laser beam according to the arrangement of width adjustment units inside the barrel. FIG. 8 is a perspective view showing the path of a laser beam reflected by a first galvanometer mirror and a second galvanometer mirror according to one embodiment. FIG. 9 is a plan view showing the path of a laser beam according to the inclination angle of a first galvanometer mirror according to one embodiment. FIG. 10 is a front view showing the path of a laser beam according to the inclination angle of a second galvanometer mirror according to one embodiment. FIG. 11 is a perspective view showing the path of a laser beam reflected by a first galvanometer mirror and a second galvanometer mirror according to one embodiment. Figure 12 is a schematic diagram comparing the cross-sectional area of ​​light according to direction when the cross-section of the laser beam is circular and when it is elliptical. Figure 13 is a cross-sectional view of the laser beam irradiated onto the substrate when the laser beam incident on the scanner part is circular. Figure 14 is a schematic diagram showing the width of the laser beam irradiated onto a substrate when the cross-section of the laser beam is circular. FIG. 15 is a perspective view of a laser processing device according to another embodiment. FIG. 16 is a schematic diagram showing the shape of a laser beam according to the arrangement of a width adjustment unit inside a barrel according to another embodiment. Specific details for implementing the invention

[0031] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0032] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may also be the second component within the technical scope of the present invention.

[0033] Specific embodiments will be described below with reference to the attached drawings.

[0034] FIG. 1 is a perspective view of a laser processing device according to one embodiment of the present invention.

[0035] Referring to FIG. 1, a laser processing device (10) according to one embodiment of the present invention is used to process a substrate (S), etc. using a laser. For example, the laser processing device (10) may be used to cut the substrate (S), apply heat to the substrate (S) or a structure on the substrate (S), or perform patterning.

[0036] A laser processing device (10) may include a laser light source (LS) that emits a laser beam (L), a width adjustment unit (100) that adjusts the width of the cross-section of the laser beam (L), a scanner unit (200) that controls the direction of travel of the laser beam (L), an F / Theta lens (300) that adjusts the focus of the laser beam (L) that has passed through the scanner unit (200), and a stage (400) on which a substrate (S) is placed.

[0037] For the convenience of explanation, the x, y, and z coordinate systems are defined in Fig. 1.

[0038] As illustrated in FIG. 1, a target substrate (S) to be laser processed is placed on the stage (400). The surface of the stage (400) may be parallel to the xy plane. The stage (400) may move along mutually orthogonal directions on the xy plane. For example, the stage (400) may move along mutually orthogonal x-axis and y-axis.

[0039] A laser light source (LS), a width adjustment unit (100), a scanner unit (200), and an F-theta lens (300) are arranged on the upper part (z-axis direction) of the stage (400). For example, the F-theta lens (300) may be arranged on the upper part of the stage (400) at a third distance from the stage (400), and the scanner unit (200) may be arranged on the upper part of the F-theta lens (300) at a third distance from the F-theta lens (300). The laser light source (LS) and the width adjustment unit (100) may be located at the same height as the scanner unit (200) with respect to the plane of the stage (400). For example, the scanner unit (200), the width adjustment unit (100), and the laser light source (LS) may be spaced apart in a second direction (x-axis direction) on the same xy plane and arranged in the order of the scanner unit (200), the width adjustment unit, and the laser light source (LS), but are not limited thereto. For example, with respect to the plane of the stage (400), the width adjustment unit (100) may be positioned higher than the scanner unit (200) and the laser light source (LS) may be positioned higher than the width adjustment unit (100), but even in this case, the scanner unit (200), the width adjustment unit (100), and the laser light source (LS) are arranged on a single straight line.

[0040] The laser light source (LS) may be various known laser generating devices. The laser light source (LS) emits a laser beam (L). The laser light source (LS) may emit the laser beam (L) continuously or discontinuously. The wavelength, amplitude, energy density, etc. of the laser beam (L) may be controlled by the laser light source (LS). The wavelength of the laser beam (L) may be 340 nm to 360 nm, but is not limited thereto. For example, the wavelength of the laser beam (L) may exceed 360 nm. The emission time of the laser beam (L) may be shorter than 1 nanosecond. For example, the emission time of the laser beam (L) may be tens of picoseconds or tens of femtoseconds, but is not limited thereto, and the emission time of the laser beam (L) may be a sufficiently long time, such as tens of seconds to minutes.

[0041] The laser light source (LS) may emit a single beam or multiple beams. In this embodiment, the case of emitting a single beam is exemplified.

[0042] A laser beam (L) emitted from a laser light source (LS) can be analyzed using a separately provided beam profiler (not shown). Specifically, the cross-section of the laser beam (L) emitted from the laser light source (LS) can be measured, and it can be determined whether the cross-section is a perfect circle or an ellipse. If the cross-section of the laser beam (L) is elliptical, the directions of the major and minor axes of the ellipse and the ratio between the length of the major axis and the length of the minor axis can be measured.

[0043] A single laser beam (L) travels in a straight line in the direction of emission and reaches the width adjustment unit (100). The width adjustment unit (100) may be positioned in the direction of travel of the laser beam (L) on the same plane as the laser light source (LS). Thus, the laser beam (L) emitted from the laser light source (LS) can pass through the width adjustment unit (100). Specifically, the laser beam (L) may enter the incident part of the width adjustment unit (100), pass through the inside of the barrel, and be emitted through the exit part of the width adjustment unit (100). The width adjustment unit (100) can adjust the width of the cross-section of the laser beam (L). Specifically, the width adjustment unit (100) can adjust the vertical and / or horizontal width of the cross-section of the laser beam (L) to change a laser beam (L) with an elliptical cross-section into a laser beam (L) with a circular cross-section. A detailed description of the width adjustment unit (100) will be provided later in FIGS. 2 to 7.

[0044] A laser beam (L) emitted from a width adjustment unit (100) reaches a scanner unit (200). The scanner unit (200) may be positioned in the direction of travel of the laser beam (L) on the same plane as the laser light source (LS) and the width adjustment unit (100). Thus, the laser beam (L) emitted from the width adjustment unit (100) can pass through the scanner unit (200). The scanner unit (200) can change the direction of travel of the incident laser beam (L) toward the stage (400) and divide a single laser beam (L) into multiple laser beams (L). The emission angle of the laser beam (L) and the number of emitted beams can be controlled by the scanner unit (200). To control the emission angle of the laser beam (L) and the number of emitted beams, the scanner unit (200) may include at least one galvanometer mirror (211, 212 in FIG. 8). A detailed description of the scanner unit (200) will be provided later in FIGS. 8 to 11.

[0045] A laser beam (L) emitted from the scanner unit (200) reaches the F-theta lens (300). The F-theta lens (300) can be spaced apart from the scanner unit (200) and positioned between the scanner unit (200) and the stage (400). Thus, the laser beam (L) emitted from the scanner unit (200) can pass through the F-theta lens (300).

[0046] The F-theta lens (300) may be a known variety of F-theta lenses (300) composed of one or more lenses. The F-theta lens (300) can adjust the focal length of a plurality of laser beams (L) emitted from the scanner unit (200) to a constant level, thereby focusing the laser beams (L) onto an area to be processed on the substrate (S).

[0047] A laser beam (L) that passes through an F-theta lens (300) can reach a substrate (S) placed on a stage (400). The laser beam (L) can be used for various purposes, such as cutting the substrate (S) or forming contact holes when manufacturing a display of a display device.

[0048] FIG. 2 is a schematic side view of the width adjustment unit with the lid closed. FIG. 3 is a schematic side view of the width adjustment unit with the lid open. FIG. 4 is a schematic diagram showing the shape of the width adjustment unit.

[0049] Referring to FIGS. 2 and 3, the width adjustment unit (100) includes a barrel and a pair of width adjustment units (120). The barrel may be in the shape of a column with a hollow interior. Although the shape of the barrel is depicted as a cylinder in the drawings, it is not limited thereto. For example, the barrel may be in various known shapes, such as a square column or a triangular column with a hollow interior. The following description assumes that the barrel is in the shape of a cylinder. The pair of width adjustment units (120) have the same shape and are made of the same material. The barrel may include an opening (110). The upper surface of the barrel may be opened using the opening (110). By opening the opening (110), the width adjustment unit (120) can be placed inside the barrel, and by closing the opening (110), the placement of the width adjustment unit (120) placed inside the barrel can be controlled. The barrel may include a fixing part (not shown) on its inner surface. The width adjustment unit (120) can be fixed using a fixed part.

[0050] A width adjustment unit (120) is positioned inside the lens barrel. Two width adjustment units (120) are positioned as a pair, and the width adjustment unit (120) positioned on the left is defined as the first width adjustment unit (121), and the width adjustment unit (120) positioned on the right is defined as the second width adjustment unit (122). Additionally, reference lines (121a, 122a) are introduced to explain the positioning and relative angles of the width adjustment units (120). The width adjustment unit (120) may have a curved elliptical shape. A pair of width adjustment units (120) may be composed of the same material, have the same shape, and have a constant refractive index. Each width adjustment unit (120) may have a convex surface and a concave surface. The width adjustment unit (120) may be an infinity with different curvatures for the convex and concave surfaces. An infinity means that the focal length of the lens is infinitely far, so that the lens power is determined to be non-existent or non-existent. The focal length of the width adjustment unit may be 20,000 mm or more. When considering the size of the laser processing device and the processing target, if the focal length of the width adjustment unit (120) used in the laser processing device is 20,000 mm or more, the focal length can be practically considered to be close to infinity. Therefore, if the focal length of the width adjustment unit (120) is 20,000 mm or more, it can be practically considered to have no power, and light incident parallel to the width adjustment unit (120) passes through the width adjustment unit (120) and can be emitted parallel again through a total of two refractions: once at the surface in the direction of incidence and once at the surface in the direction of emission. By arranging a pair of width adjustment units (120), a laser beam (L) incident parallel to the width adjustment unit (100) can be emitted parallel after a total of four refractions.In this way, when a width adjustment unit (120) with a focal length practically close to infinity is placed in the laser processing device and the paths of the laser beam (L) incident on the width adjustment unit (120) and the laser beam (L) exiting are parallel, when the laser beam (L) exiting from the width adjustment unit (120) passes through the F-theta lens (300), aberration problems such as Petzval field curvature do not occur, so it can be effective for correcting the circle of the laser beam (L).

[0051] Referring to FIG. 4, the width adjustment unit (120) may have a curved elliptical shape.

[0052] The width adjustment unit (120) may be shaped like an ellipse having a major axis and a minor axis, bent in a direction where the ends of both major axes come closer together. Specifically, the width adjustment unit (120) may have a convex surface and a concave surface, and the convex surface and the concave surface may be bent in the same direction, and the radius of curvature of the convex surface and the concave surface may be different. For example, the radius of curvature of the convex surface may be 23 to 24 mm and the radius of curvature of the concave surface may be 19 to 21 mm. When the radius of curvature of the convex surface is set to 23.348 mm and the radius of curvature of the concave surface is set to 20 mm, and the thickness is set to 10 mm, the effective focal length (EFL) of the width adjustment unit (120) may be 38040 mm, which is virtually close to infinity, but the radius of curvature of the concave surface and the convex surface is not limited thereto. For example, the radius of curvature of the concave surface and the radius of curvature of the convex surface can have various values ​​that make the width adjustment unit (120) an infinite circle having an infinite focal length.

[0053] In the cross-sectional view, the width adjustment unit (120) may be in the shape of a column bent in one direction. Due to the curvature of the width adjustment unit (120), a portion of the upper part of the concave surface and a portion of the lower part of the concave surface may face each other, but are not limited thereto. For example, if the curvature of the concave surface is sufficiently large, a portion of the upper part of the concave surface and a portion of the lower part of the concave surface face each other, but if the curvature of the concave surface is small, there may not be any portion of the upper and lower parts of the concave surface facing each other.

[0054] The side of the width adjustment unit (120) may have a flat shape and be parallel to the side facing each other. By making the shape of the side of the width adjustment unit (120) flat and parallel to the side facing it, the effect of external impact is reduced when the width adjustment unit (120) is placed inside the barrel, and even when the width adjustment unit (120) is rotated and placed, the space occupied by the width adjustment unit (120) remains the same, allowing for easy placement inside the barrel, but this is not limited thereto. For example, the side of the width adjustment unit (120) may not be parallel to the side facing it, and a separate fixing part capable of adjusting the width may be provided in the placement space of the width adjustment unit (120) inside the barrel.

[0055] In the plan view, the width adjustment unit (120) may be a circle with equal vertical and horizontal lengths. Even when the width adjustment unit (120) is rotated and positioned with the shape of the width adjustment unit (120) in the plan view as a circle, it occupies the same space inside the barrel, allowing the width adjustment unit (120) to be easily rotated and positioned without changing the internal space of the barrel itself.

[0056] Although the above description assumes that the shape of the width adjustment unit (120) in the plan view is circular, the shape of the width adjustment unit (120) is not limited thereto. For example, the width adjustment unit (120) may have a square or rectangular shape in the plan view, or a triangular shape. However, even in this case, the width adjustment unit (120) may have a curved column shape in the cross-sectional view, and may have concave and convex surfaces. For convenience of explanation, the following description assumes that the width adjustment unit (120) has a circular shape in the plan view.

[0057] The width adjustment unit (120) may be made of various optical glasses that constitute known lenses. For example, the width adjustment glass may include plate glass, cast glass, Pyrex glass, Duran glass, Zero Dewar glass, etc. The width adjustment unit (120) may include a transparent material having a refractive index different from that of air, so that an incident laser can pass through the width adjustment unit (120) by being refracted a total of two times, once on the convex surface and once on the concave surface.

[0058] By opening the opening (110) of the barrel according to the cross-sectional shape of the laser beam (L) emitted from the laser light source (LS), and adjusting the placement of the first width adjustment unit (121) and the angle between the first width adjustment unit (121) and the second width adjustment unit (122), the laser beam (L) with a cross-section of various proportions can be adjusted into a laser beam (L) with a cross-section of a perfect circle.

[0059] FIGS. 5 to 7 are schematic diagrams showing the shape of a laser beam according to the arrangement of width adjustment units inside the barrel.

[0060] Referring to FIG. 5, a first width adjustment unit (121) and a second width adjustment unit (122) can be arranged inside the barrel such that both reference lines (121a, 122a) are parallel to each other. A laser beam (L) incident on the barrel passes through the first width adjustment unit (121), is refracted to contract in the vertical direction perpendicular to the reference line (121a), and is emitted in the same direction as the incident direction. Since the first width adjustment unit (121) is infinite, the laser incident on the first width adjustment unit (121) and the emitted laser can be parallel to each other. The laser beam (L) emitted from the first width adjustment unit (121) passes through the second width adjustment unit (122), is refracted, and can contract once again in the vertical direction perpendicular to the reference line (122a). Since the second width adjustment unit (122) is also an infinite circle like the first width adjustment unit (121), the laser incident on the second width adjustment unit (122) and the laser emitted can be parallel to each other. In summary, the laser beam (L) incident on the width adjustment unit (100) can be emitted parallel to the direction of incidence after contracting twice in the vertical direction. Therefore, a laser beam (L) with an elliptical cross-section in which the vertical direction is the major axis and the horizontal direction is the minor axis can be passed through a pair of width adjustment units (120) to contract the major axis and maintain the minor axis, thereby adjusting the laser beam (L) to have a circular cross-section.

[0061] For a detailed explanation, a cross-sectional view of the laser beam (L) incident on the barrel, a cross-sectional view of the laser beam (L) after passing through the first width adjustment unit (121), and a cross-sectional view of the laser beam (L) after passing through the second width adjustment unit (122) are compared. When comparing the cross-sectional views of the three points, the length of the horizontal axis has the same value of x for all three points, the length of the vertical axis y1 of the laser beam (L) incident on the barrel has the largest value, the length of the vertical axis y2 of the laser beam (L) after passing through the first width adjustment unit (121) has a value smaller than y1, and the length of the vertical axis y3 of the laser beam (L) after passing through the second width adjustment unit (122) may have a value smaller than y2. And if y3 is set to have the same value as x, the length of the vertical axis and the length of the horizontal axis of the laser beam (L) become equal, so the laser beam (L) with an elliptical cross section can be adjusted into a laser beam (L) with a circular cross section.

[0062] In particular, by making the same arrangement, when the radius of curvature of the convex surface of the width adjustment unit (120) is 23.348 mm, the radius of curvature of the concave surface is 20 mm, and the thickness is 10 mm, the laser beam (L) having an elliptical cross-section with a major axis to minor axis ratio of 1.5 to 1 can be adjusted into a laser beam (L) having a circular cross-section.

[0063] Referring to FIG. 6, a first width adjustment unit (121) and a second width adjustment unit (122) can be arranged inside the barrel such that both reference lines (121a, 122a) are perpendicular to each other. A laser beam (L) incident on the barrel passes through the first width adjustment unit (121), is refracted to contract in the up-down direction, which is perpendicular to the reference line (121a), and is emitted in the same direction as the incident direction. Since the first width adjustment unit (121) is infinite, the laser incident on the first width adjustment unit (121) and the emitted laser can be parallel to each other. The laser beam (L) emitted from the first width adjustment unit (121) passes through the second width adjustment unit (122), is refracted, and can contract once again in the left-right direction, which is perpendicular to the reference line (122a). Since the second width adjustment unit (122) is also an infinite circle like the first width adjustment unit (121), the laser incident on the second width adjustment unit (122) and the laser emitted can be parallel to each other. In summary, the laser beam (L) incident on the width adjustment unit (100) can contract once in the vertical direction and once in the horizontal direction, and then be emitted parallel to the direction of incidence. Therefore, a perfectly circular laser beam (L) can be incident, pass through a pair of width adjustment units (120), and contract in both the vertical and horizontal directions to be adjusted into a perfectly circular laser beam (L) with a reduced cross-sectional area.

[0064] For specific explanation, a cross-sectional view of the laser beam (L) incident on the barrel, a cross-sectional view of the laser beam (L) after passing through the first width adjustment unit (121), and a cross-sectional view of the laser beam (L) after passing through the second width adjustment unit (122) are compared. When comparing the cross-sectional views of the three points, the horizontal axis lengths x1, which is the horizontal axis length of the laser beam (L) incident on the barrel, and x2, which is the horizontal axis length of the laser beam (L) after passing through the first width adjustment unit (121), have the same value, and x3, which is the horizontal axis length of the laser beam (L) after passing through the second width adjustment unit (122), may have a value smaller than x1 and x2. Additionally, the length of the vertical axis y1, which is the length of the vertical axis of the laser beam (L) incident on the barrel, has the largest value, and y2, which is the length of the vertical axis of the laser beam (L) that has passed through the first width adjustment unit (121), and y3, which is the length of the vertical axis of the laser beam (L) that has passed through the second width adjustment unit (122), may have the same value.

[0065] Referring to FIG. 7, a first width adjustment unit (121) and a second width adjustment unit (122) can be arranged inside the barrel such that both reference lines (121a, 122a) are at an angle of 45° to each other. A laser beam (L) incident on the barrel passes through the first width adjustment unit (121), is refracted, contracts in the up-down direction which is perpendicular to the reference line (121a), and is emitted in the same direction as the incident direction. Since the first width adjustment unit (121) is infinite, the laser incident on the first width adjustment unit (121) and the emitted laser can be parallel to each other. A laser beam (L) emitted from the first width adjustment unit (121) passes through the second width adjustment unit (122), is refracted, contracts in the up-down and left-right directions which are perpendicular to the reference line (122a), and is emitted in the same direction as the incident direction. Since the second width adjustment unit (122) is also an infinite circle like the first width adjustment unit (121), the laser incident on the second width adjustment unit (122) and the laser emitted can be parallel to each other. In summary, the laser beam (L) incident on the width adjustment unit (100) can be emitted parallel to the direction of incidence after contracting once in the vertical direction and once in the vertical and horizontal directions. Therefore, a laser beam (L) with an elliptical cross-section in which the vertical direction is the major axis and the horizontal direction is the minor axis is incident, passes through the first width adjustment unit (121) to become a laser beam (L) with a circular cross-section, and passes through the second width adjustment unit (122) to be adjusted into a laser beam (L) with a reduced cross-sectional area.

[0066] For specific explanation, a cross-sectional view of the laser beam (L) incident on the barrel, a cross-sectional view of the laser beam (L) after passing through the first width adjustment unit (121), and a cross-sectional view of the laser beam (L) after passing through the second width adjustment unit (122) are compared. When comparing the cross-sectional views of the three points, the horizontal axis lengths x1, which is the horizontal axis length of the laser beam (L) incident on the barrel, and x2, which is the horizontal axis length of the laser beam (L) after passing through the first width adjustment unit (121), have the same value, and x3, which is the horizontal axis length of the laser beam (L) after passing through the second width adjustment unit (122), may have a value smaller than x1 and x2. In addition, the length of the vertical axis y1, which is the length of the vertical axis of the laser beam (L) incident on the barrel, has the largest value, y2, which is the length of the vertical axis of the laser beam (L) that has passed through the first width adjustment unit (121), has a value smaller than y1, and y3, which is the length of the vertical axis of the laser beam (L) that has passed through the second width adjustment unit (122), may have a value smaller than y2.

[0067] In this case, since the change in length in the direction perpendicular to the reference line (121a, 122a) is greater than the change in length in the direction forming an angle of 45° with the reference line (121a, 122a), the value of y2 / y1 may be smaller than the value of y3 / y2.

[0068] In the above description, in each case, the first width adjustment unit (121) has the same arrangement and the arrangement of the second width adjustment unit (122) is adjusted to describe various angles between the first width adjustment unit (121) and the second width adjustment unit (122), but this is not limited thereto. For example, the second width adjustment unit (122) may be fixed and the angle between the first width adjustment unit (121) and the second width adjustment unit (122) may be adjusted by adjusting the arrangement of the first width adjustment unit (121), and the arrangement of the first width adjustment unit (121) and the second width adjustment unit (122) may be adjusted together.

[0069] As described above, the cross-section of the laser beam (L) emitted by the laser light source (LS) can be adjusted by adjusting the arrangement of the width adjustment unit (120) included in the width adjustment unit (100) according to the cross-sectional shape of the laser beam (L) emitted by the laser light source (LS) analyzed using a separately provided beam profiler (not shown). Specifically, when the cross-section of the laser beam (L) emitted by the laser light source (LS) is circular, the reference lines (121a, 122a) of the first width adjustment unit (121) and the second width adjustment unit (122) can be arranged in a direction perpendicular to each other in order to maintain the cross-section of the laser beam (L) emitted from the width adjustment unit (100) as circular. Through this, the direction in which the first width adjustment unit (121) contracts the laser beam (L) and the direction in which the second width adjustment unit (122) contracts the laser beam (L) are perpendicular to each other, so that as a result, the cross-section of the laser beam (L) that has passed through the width adjustment unit (100) can also be made circular.

[0070] If the cross-section of the laser beam (L) is an ellipse with a ratio of the major axis to the minor axis of 1.5:1 or greater, the first width adjustment unit (121) and the second width adjustment unit (122) can be arranged so that the reference lines (121a, 122a) of the first width adjustment unit (121) and the second width adjustment unit (122) are both perpendicular to the major axis of the cross-section of the laser beam (L), thereby reducing the difference in length between the major axis and the minor axis of the laser beam (L).

[0071] When the ratio of the major axis to the minor axis of the cross-section of the laser beam (L) is between 1:1 and 1.5:1, the cross-section of the laser beam (L) can be aligned to a perfect circle by adjusting the angle between the reference lines (121a, 122a) of the first width adjustment unit (121) and the second width adjustment unit (122) to between 0° and 90°. For example, the first width adjustment unit (121) can be positioned so that the reference line (121a) of the first width adjustment unit (121) is perpendicular to the major axis of the laser beam (L), and the second width adjustment unit (122) can be positioned so that the reference line (122a) of the second width adjustment unit (122) has an angle of 45° with the reference line (121a) of the first width adjustment unit (121), thereby mitigating the difference in length between the major axis and the minor axis of the cross-section of the laser beam (L).

[0072] FIG. 8 is a perspective view showing the path of a laser beam reflected by a first galvanometer mirror and a second galvanometer mirror according to one embodiment. FIG. 9 is a plan view showing the path of a laser beam according to the inclination angle of the first galvanometer mirror according to one embodiment. FIG. 10 is a front view showing the path of a laser beam according to the inclination angle of the second galvanometer mirror according to one embodiment.

[0073] Referring to FIGS. 8 to 10, the scanner may include a first galvanometer mirror (211) and a second galvanometer mirror (212). The first galvanometer mirror (211) and the second galvanometer mirror (212) may be made of various materials capable of reflecting an incident laser beam (L) or light. The first galvanometer mirror (211) can adjust the relative angle with respect to the laser light source (LS) and the width adjustment unit (100), and the second galvanometer mirror (212) can adjust the relative angle with respect to the first galvanometer mirror (211).

[0074] The first galvanometer mirror (211) controls the path of the laser beam (L) in the first direction (y-axis direction) by adjusting the angle of inclination on the xy plane.

[0075] The second galvanometer mirror (212) controls the path of the laser beam (L) in the second direction (x-axis direction) by adjusting the angle of inclination on the xz plane. Here, the second direction (x-axis direction) means a direction that is not parallel to the first direction (y-axis direction).

[0076] The first galvanometer mirror (211) and the second galvanometer mirror (212) may be positioned at the same height as the laser light source (LS) with respect to the plane of the stage (400). However, this is not limited thereto, and the second galvanometer mirror (212) may be positioned between the first galvanometer mirror (211) and the stage (400).

[0077] The first galvanometer mirror (211) can be placed in the path of a straight laser beam (L) emitted from the width adjustment unit (100).

[0078] The second galvanometer mirror (212) can be placed in the path of the laser beam (L) that is reflected from the first galvanometer mirror (211).

[0079] Hereinafter, Fig. 9 is referenced for a more detailed explanation of the path of the laser beam (L) according to the inclination angle of the first galvanometer mirror (211).

[0080] The reflective surface of the first galvanometer mirror (211) can be positioned toward the laser light source (LS) and the width adjustment unit (100). A laser beam (L) emitted from the laser light source (LS) can pass through the width adjustment unit (100) and be incident on the reflective surface of the first galvanometer mirror (211). A laser beam (L) traveling in a straight line in one direction is reflected by the first galvanometer mirror (211) in a direction other than the one direction that is not parallel to the one direction. For example, as shown in FIG. 9, when the laser beam (L) travels in a straight line in the first direction (y-axis direction), the laser beam (L) reflected by the first galvanometer mirror (211) travels in a direction approximately similar to the second direction (x-axis direction) and reaches the second galvanometer mirror (212) located in that direction.

[0081] The first galvanometer mirror (211) can rotate to have a plurality of discontinuous inclinations (rotation angles) in the xy plane. For example, the first galvanometer mirror (211) can rotate to have a first inclination and a second inclination different from it in the xy plane. If a virtual straight line having the average inclination of the first inclination and the second inclination is defined as the first auxiliary line (CL1), the first inclination has an angle α in the counterclockwise direction with respect to the first auxiliary line (CL1), and the second inclination has an angle α in the clockwise direction. The angle between the first inclination and the second inclination is 2α.

[0082] The laser beam (L) incident on the first galvanometer mirror (211) has an angle of incidence that varies depending on the inclination of the first galvanometer mirror (111). For example, assuming the laser beam (L) has an angle of incidence of 45° with respect to the first auxiliary line (CL1), when the first galvanometer mirror (211) has a first inclination, the angle of incidence is (45°+α), and when the first galvanometer mirror (211) has a second inclination, the angle of incidence is (45°-α).

[0083] When the first galvanometer mirror (211) has a first tilt, the laser beam (L) has a reflection angle of (45°+α) according to the law of reflection, and when it has a second tilt, it has a reflection angle of (45°-α).

[0084] The point P where the laser beam (L) reflected by the first galvanometer mirror (211) having the first slope meets the second galvanometer mirror (212) L1 The point where the laser beam (L) reflected by the first galvanometer mirror (211) having a second slope meets the second galvanometer mirror (212) is called P. L2 It is called. P L1 and P L2 They are spaced apart from each other along the first direction (y-axis direction) on the xy plane.

[0085] Since the angle of incidence and the angle of reflection of the laser beam (L) vary depending on the inclination of the first galvanometer mirror (211), even if the laser beam (L) is incident on the same point of the first galvanometer mirror (211), the point of incidence on the second galvanometer mirror (212) is different.

[0086] Hereinafter, Fig. 10 is referenced for a more detailed explanation of the path of the laser beam (L) according to the inclination angle of the second galvanometer mirror (212).

[0087] The reflective surface of the second galvanometer mirror (212) may be positioned toward the first galvanometer mirror (211). A laser beam (L) reflected from the first galvanometer mirror (211) is incident on the reflective surface of the second galvanometer mirror (212). A laser beam (L) traveling in a straight line in one direction may be reflected toward the F-theta lens (300) by the second galvanometer mirror (212). FIG. 10 illustrates a case where a laser beam (L) traveling in a straight line in the second direction (x-axis direction) is reflected toward the F-theta lens (300).

[0088] The second galvanometer mirror (212) can rotate to have a plurality of continuous inclinations (rotation angles) on the xz plane. The second galvanometer mirror (212) can rotate continuously within a range of a third inclination and a fourth inclination different therefrom on the xz plane. If a virtual straight line having the average inclination of the third inclination and the fourth inclination is defined as the second auxiliary line (CL2), then with respect to the second auxiliary line (CL2), the third inclination has an angle β in the counterclockwise direction, and the fourth inclination has an angle β in the clockwise direction. The angle between the third inclination and the fourth inclination is 2β.

[0089] The laser beam (L) incident on the second galvanometer mirror (212) has an angle of incidence that varies depending on the inclination of the second galvanometer mirror (212). For example, assuming the laser beam (L) has an angle of incidence of 45° relative to the second auxiliary line (CL2), when the second galvanometer mirror (212) has a third inclination, the angle of incidence is (45°+β), when the second galvanometer mirror (212) has the same inclination as the second auxiliary line (CL2), the angle of incidence is 45°, and when the second galvanometer mirror (212) has a fourth inclination, the angle of incidence is (45°-β).

[0090] The angle of reflection depends on the inclination of the second galvano mirror (212). According to the law of reflection, if the angle of incidence changes, the angle of reflection changes to the same value as the angle of incidence.

[0091] FIG. 11 is a perspective view showing the path of a laser beam reflected by a first galvanometer mirror and a second galvanometer mirror according to one embodiment.

[0092] Referring to FIGS. 1 and FIGS. 11, a laser beam (L) reflected by the second galvanometer mirror (212) passes through an F-theta lens (300). The F-theta lens (300) may be located between the scanner unit (200) and the stage (400). The F-theta lens (300) may be composed of multiple lenses, such as a known F-theta lens (300), but is not limited thereto. For example, F / theta may be composed of a single lens having different refractive indices at each point of incidence, or it may be composed of a single lens having the same refractive index.

[0093] The F-theta lens (300) can adjust the focal length of the laser beam (L) to a constant level so that the laser beam (L) can be focused on an area to be processed on the substrate (S). The laser beam (L) passing through the F-theta lens (300) can reach the substrate (S).

[0094] Below, the optical path of the laser beam (L) according to the inclination of the first galvanometer mirror (211) and the second galvanometer mirror (212) is described in detail.

[0095] First, the optical path of the first laser beam (L1) is described when the first galvanometer mirror (211) has a first inclination and the second galvanometer mirror (212) has a third inclination. The first laser beam (L1) is incident on the first galvanometer mirror (211) having the first inclination, reflected, and incident on the second galvanometer mirror (212). In the drawing, the point where the first laser beam (L1) is incident is indicated as PL1.

[0096] The first laser beam (L1) incident on the second galvanometer mirror (212) having a third slope is reflected by the second galvanometer mirror (212) at a reflection angle equal to the angle of incidence according to the law of reflection. The first laser beam (L1) reflected by the second galvanometer mirror (212) passes through the F-theta lens (300) and reaches the substrate (S). Specifically, it reaches P1, a point on SL1, which is a virtual straight line on the substrate (S). The SL1 may be parallel to the second direction (x-axis direction).

[0097] Next, the optical path of the second laser beam (L2) is described when the first galvanometer mirror (211) has a first inclination and the second galvanometer mirror (212) has the same inclination as the second auxiliary line (CL2).

[0098] The second laser beam (L2), like the first laser beam (L1), is incident on and reflected toward the first galvanometer mirror (211) and reaches point PL1 of the second galvanometer mirror (212). The second laser beam (L2) incident on the second galvanometer mirror (212) is reflected at an angle equal to the angle of incidence according to the law of reflection; however, because the second galvanometer mirror (212) has the same inclination as the second auxiliary line (CL2), the direction of reflection is different from that of the first laser beam (L1). Thus, the second laser beam (L2) reflected from the second galvanometer mirror (212) passes through the F-theta lens (300) and reaches point P2 on SL1 existing on the substrate (S). Here, P2 is spaced apart from P1 along the second direction (x-axis direction).

[0099] Next, the optical path of the third laser beam (L3) is described when the first galvanometer mirror (211) has a first inclination and the second galvanometer mirror (212) has a third inclination.

[0100] The third laser beam (L3), like the first laser beam (L1), is incident on and reflected toward the first galvanometer mirror (211) and reaches point PL1 of the second galvanometer mirror (212). The third laser beam (L3) incident on the second galvanometer mirror (212) is reflected at an angle equal to the angle of incidence according to the law of reflection; however, because the second galvanometer mirror (212) has a third tilt, the direction of reflection is different from that of the first laser beam (L1) and the second laser beam (L2). Thus, the third laser beam (L3) reflected from the second galvanometer mirror (212) passes through the F-theta lens (300) and reaches P3 on SL1 existing on the substrate (S). Here, P3 is further separated from P1 along the second direction (x-axis direction).

[0101] The point where the first laser beam (L1) to the third laser beam (L3) reaches the substrate (S) varies depending on the degree of rotation of the second galvanometer mirror (212). Since the second galvanometer mirror (212) can rotate continuously, the laser beam (L) can reach the substrate (S) through all paths between the first laser beam (L1) to the third laser beam (L3). That is, the laser beam (L) meets the substrate (S) in all areas included in the imaginary line connecting P1 and P3. Here, the imaginary line segment connecting P1 and P3 becomes the first scanning line (SL2).

[0102] Next, the optical path of the fourth laser beam (L4) is described when the first galvanometer mirror (211) has a second inclination and the second galvanometer mirror (212) has a third inclination.

[0103] The fourth laser beam (L4) is incident on the first galvanometer mirror (211) having a second inclination, reflected, and incident on the second galvanometer mirror (212). In the drawing, the point where the fourth laser beam (L4) is incident is indicated as PL2.

[0104] The fourth laser beam (L4) incident on the second galvanometer mirror (212) having a third inclination is reflected by the second galvanometer mirror (212) at an angle of reflection equal to the angle of incidence according to the law of reflection. The fourth laser beam (L4) reflected by the second galvanometer mirror (212) passes through the F-theta lens (300) and reaches the substrate (S). Specifically, it reaches P4, a point on SL2, which is a virtual straight line on the substrate (S). The SL2 may be parallel to the second direction (x-axis direction).

[0105] Next, the optical path of the fifth laser beam (L5) is described when the first galvanometer mirror (211) has a second inclination and the second galvanometer mirror (212) has the same inclination as the second auxiliary line (CL2).

[0106] The fifth laser beam (L5), like the fourth laser beam (L4), is incident on and reflected toward the first galvanometer mirror (211) and reaches point PL2 of the second galvanometer mirror (212). The fifth laser beam (L5) incident on the second galvanometer mirror (212) is reflected at an angle equal to the angle of incidence according to the law of reflection; however, because the second galvanometer mirror (212) has the same inclination as the second auxiliary line (CL2), the direction of reflection is different from that of the fourth laser beam (L4). Thus, the fifth laser beam (L5) reflected from the second galvanometer mirror (212) passes through the F-theta lens (300) and reaches point P5 on SL2 existing on the substrate (S). Here, P5 is separated from P4 along the second direction (x-axis direction).

[0107] Next, the optical path of the sixth laser beam (L6) is described when the first galvanometer mirror (211) has a second inclination and the second galvanometer mirror (212) has a third inclination.

[0108] The sixth laser beam (L6), like the fourth laser beam (L4), is incident on and reflected toward the first galvanometer mirror (211) and reaches point PL2 of the second galvanometer mirror (212). The sixth laser beam (L6) incident on the second galvanometer mirror (212) is reflected at an angle equal to the angle of incidence according to the law of reflection; however, because the second galvanometer mirror (212) has a third tilt, the direction of reflection is different from that of the fourth laser beam (L4) and the fifth laser beam (L5). Thus, the sixth laser beam (L6) reflected from the second galvanometer mirror (212) passes through the F-theta lens (300) and reaches point P6 on SL2 existing on the substrate (S). Here, P6 is further separated from P4 along the second direction (x-axis direction).

[0109] Since the second galvanometer mirror (212) can rotate continuously, when the first galvanometer mirror (211) has a first tilt, the laser beam (L) can travel along all paths between the fourth laser beam (L4) and the sixth laser beam (L6). In other words, the laser beam (L) can reach all areas included in the imaginary line connecting P4 and P6. Here, the imaginary line segment connecting P4 and P6 becomes the second scanning line (SL2).

[0110] The lengths of the first scanning line (SL2) and the second scanning line (SL2) are determined by the rotation angle (2β) of the second galvanometer mirror (212) and the distance between the scanner unit (200) and the stage (400).

[0111] The first scanning line (SL2) and the second scanning line (SL2) are spaced apart at a constant interval along the first direction (y-axis direction). The spacing is proportional to the angle (2α) between the first and second inclinations of the first galvanometer mirror (211) and the distance between the scanner unit (200) and the stage (400).

[0112] FIG. 12 is a schematic diagram comparing the cross-sectional area of ​​light according to direction when the cross-section of the laser beam is circular and when it is elliptical. FIG. 13 is a cross-sectional view of the laser beam irradiated onto the substrate when the laser beam incident on the scanner part is circular. FIG. 14 is a schematic diagram showing the width of the laser beam irradiated onto the substrate when the cross-section of the laser beam is circular.

[0113] Referring to FIG. 12, the laser beam (L) is light that is a collection of infinitely many wavelengths and therefore does not have directionality in a specific direction. Therefore, unless it is polarized by passing through a polarizer or the like, the magnitude of the energy transmitted by the laser beam (L) is determined by the area of ​​the cross-sectional area of ​​the laser beam (L).

[0114] As shown on the left side of the drawing, when the cross-section of the laser beam (L) is circular, the width of the laser beam can be the same as d1 in the same plane as the cross-section, in the left-right and up-down directions, as well as in the diagonal direction between them. Therefore, when L-shaped processing of a processing target using a laser beam with a circular cross-section, the width of the laser beam irradiated onto the processing target in the up-down and left-right directions is the same as d1, so there may be no directional dependency. Therefore, using a laser beam with a circular cross-section allows for efficient processing of the processing target without additional processing depending on the direction.

[0115] On the other hand, as illustrated on the right side of the drawing, if the cross-section of the laser beam (L) is elliptical, the cross-sectional area may differ depending on the direction. For the purpose of explanation, as shown in the drawing, an ellipse is assumed as the cross-section of the laser beam where the vertical direction is the major axis and the horizontal direction is the minor axis. In the same plane as the cross-section of the laser beam, the vertical width of the laser beam may be d2. The horizontal width of the laser beam may be d3, which is greater than d2. In the direction between the vertical direction and the horizontal direction, the width of the laser beam may have a value between d2 and d3. Therefore, when L-shaped processing is performed on a processing target using such a laser beam, the width of the laser beam received by the processing target may be narrower in the vertical direction than in the horizontal direction. Since the area and width of the laser irradiated differ depending on the direction, direction dependency may exist during laser beam processing. In such cases where the cross-section of the laser beam is elliptical, problems may arise where precise processing is impossible or additional design is required depending on the direction due to the direction dependency of the laser beam.

[0116] Therefore, if a laser beam (L) with an elliptical cross section can be adjusted to a laser beam (L) with a circular cross section depending on the purpose of use of the laser beam (L), more efficient processing can be achieved with the laser beam (L) emitted from the same laser light source (LS).

[0117] A laser processing device that operates by changing the propagation path of a laser beam (L) in various directions may be advantageous when the cross-section of the laser beam (L) being irradiated is circular, and may use a width adjustment unit (100) to adjust the laser beam (L) with an elliptical cross-section to a laser beam (L) with a circular cross-section, but is not limited thereto. For example, in some embodiments, there may be a difference in the energy required for each propagation path of the laser beam (L), and the case where the cross-section of the laser beam (L) is elliptical may be more advantageous than the case where the cross-section of the laser beam (L) is circular, so in this case, the cross-section of the laser beam (L) may be adjusted from a circular to an elliptical using a width adjustment unit (100). However, the following description is based on the premise that the cross-section of the laser beam (L) is adjusted from an elliptical to a circular using a width adjustment unit (100).

[0118] Referring to FIGS. 13 and 14, when a laser beam (L) with an elliptical cross section is adjusted to a laser beam (L) with a circular cross section using a width adjustment unit (100) according to one embodiment, the cross sections of the laser beam (L) reaching each position on the substrate (S) can all be circular. As described above, since the laser beam (L) with a circular cross section has no directionality in the plane, the cross section can still be circular at all irradiation positions even after being reflected by the scanner unit (200) and refracted by the f-theta lens (300). The diameter of the cross section of the laser beam (L) irradiated onto the substrate (S) is defined as d. A stage (400) placed on the lower surface of the substrate (S) can move in various directions in the plane to cut the substrate (S). A laser beam (L) with a circular cross-section has no directionality, and since all laser beams (L) irradiated onto the substrate (S) are circular, the width of the area irradiated by the laser beam (L) can always be d, which is equal to the diameter of the laser beam (L), even if it moves in various directions. Therefore, even if the cross-section of the laser beam (L) emitted by the laser light source (LS) is elliptical, the laser beam (L) can be irradiated with the same width and the same intensity at all locations where the laser beam (L) is irradiated by using the width adjustment unit (100). By maintaining the width and intensity of the laser beam (L) irradiated onto the substrate (S) constant, fine processing of the substrate (S) can be performed using the laser beam (L) by adjusting only the movement of the stage (400).

[0119] In one embodiment, the width adjustment unit (120) is an infinite circle with an infinite focal length, so the width adjustment unit (120) may not have a degree. Therefore, each part of the laser beam (L) incident on the width adjustment unit (100) equipped with the width adjustment unit (120) is emitted in a direction parallel to the incident beam, and the emitted laser beams (L) can all travel in directions parallel to each other. Therefore, even if each laser beam (L) is refracted while passing through the F-theta lens (300), aberrations such as curvature of the image plane may not occur.

[0120] FIG. 15 is a perspective view of a laser processing device according to another embodiment.

[0121] The laser processing device according to the present embodiment differs from the embodiment of FIG. 1 in that it further includes a beam expander (500) positioned between a laser light source (LS) and a width adjustment unit (100), the first width adjustment unit (121) and the second width adjustment unit (122) have different shapes, and the concave surface of the first width adjustment unit (121) and the concave surface of the second width adjustment unit (122) are positioned opposite each other.

[0122] Referring to FIG. 15, the laser processing device (10) may include a laser light source (LS) that emits a laser beam (L), a beam expander (500) that increases the overall diameter of the laser beam (L), a width adjustment unit (100) that adjusts the width of the cross-section of the laser beam (L), a scanner unit (200) that controls the direction of travel of the laser beam (L), an F-theta lens (300) that adjusts the focus of the laser beam (L) that has passed through the scanner unit (200), and a stage (400) on which a substrate (S) is placed.

[0123] As illustrated in FIG. 15, a target substrate (S) to be laser processed is placed on the stage (400). The surface of the stage (400) may be parallel to the xy plane. The stage (400) may move along mutually orthogonal directions on the xy plane. For example, the stage (400) may move along mutually orthogonal x-axis and y-axis.

[0124] A laser light source (LS), a width adjustment unit (100), a scanner unit (200), and an F-theta lens (300) are arranged on the upper part (z-axis direction) of the stage (400). For example, the F-theta lens (300) may be arranged on the upper part of the stage (400) at a third distance from the stage (400), and the scanner unit (200) may be arranged on the upper part of the F-theta lens (300) at a third distance from the F-theta lens (300). The laser light source (LS), the beam expander (500), and the width adjustment unit (100) may be located at the same height as the scanner unit (200) with respect to the plane of the stage (400). For example, the scanner unit (200), width adjustment unit (100), beam expander (500), and laser light source (LS) may be spaced apart in a second direction (x-axis direction) on the same xy plane and arranged in the order of scanner unit (200), width adjustment unit, beam expander (500), and laser light source (LS), but are not limited thereto. For example, with respect to the plane of the stage (400), the width adjustment unit (100) may be positioned higher than the scanner unit (200), the beam expander (500) may be positioned higher than the width adjustment unit (100), and the laser light source (LS) may be positioned higher than the beam expander (500), but even in this case, the scanner unit (200), width adjustment unit (100), beam expander (500), and laser light source (LS) are arranged on a single straight line.

[0125] The laser light source (LS), scanner unit (200), F-theta lens (300), substrate (S), and stage (400) are the same as those described in the above-described embodiment and are therefore omitted.

[0126] The beam expander (500) is positioned between the laser light source (LS) and the width adjustment unit (100) to adjust and transmit the diameter of the laser transmitted to the width adjustment unit (100). The beam expander (500) serves to increase the overall diameter of the laser output from the laser light source (LS) at a small diameter. Through this, the laser transmitted to the width adjustment unit (100) adjusts the relative size with respect to the width adjustment unit (120) of the width adjustment unit (100). However, the diameter of the laser beam (L) incident on the width adjustment unit (100) after passing through the beam expander (500) and increasing its diameter must be smaller than the diameter of the width adjustment unit (120).

[0127] FIG. 16 is a schematic diagram showing the shape of a laser beam according to the arrangement of a width adjustment unit inside a barrel according to another embodiment.

[0128] According to another embodiment, the first width adjustment unit (121) and the second width adjustment unit (122) may differ from each other in shape and / or material, etc. Specifically, the refractive index of the concave surface of the first width adjustment unit (121) may differ from the refractive index of the concave surface of the second width adjustment unit (122), and the refractive index of the convex surface of the first width adjustment unit (121) may differ from the refractive index of the convex surface of the second width adjustment unit (122). However, even in this case, the first width adjustment unit (121) and the second width adjustment unit (122) are both infinite circles with an infinite focal length.

[0129] In addition, the constituent materials and molecular structures of the first width adjustment unit (121) and the second width adjustment unit (122) may be different. However, even in this case, both the first width adjustment unit (121) and the second width adjustment unit (122) are made of transparent optical glass.

[0130] In another embodiment, the width adjustment unit (120) also has an infinite focal length and is optically transparent to transmit light, so the laser beam (L) incident on the width adjustment unit (120) can be emitted in the same direction as the incident direction through two refractions. When the laser beam (L) is incident on the convex surface of the width adjustment unit (120) and emitted from the concave surface, the overall cross-sectional area of ​​the laser beam (L) is reduced because, as described above, the refractive index of the width adjustment unit (120) is higher than the refractive index of air. Conversely, when the laser beam (L) is incident on the concave surface of the width adjustment unit (120) and emitted from the convex surface, the overall cross-sectional area of ​​the laser beam (L) increases.

[0131] For a more specific explanation, as shown in FIG. 16, the concave surfaces of the first width adjustment unit (121) and the second width adjustment unit (122) face each other, and the reference line (121a) of the first width adjustment unit (121) and the reference line (122a) of the second width adjustment unit (122) are arranged perpendicular to each other.

[0132] The laser beam (L) incident on the barrel passes through the first width adjustment unit (121), is refracted to contract in the vertical direction perpendicular to the reference line (121a), and is emitted in the same direction as the incident direction. Since the first width adjustment unit (121) is infinite, the laser incident on the first width adjustment unit (121) and the emitted laser can be parallel to each other. The laser beam (L) emitted from the first width adjustment unit reaches the second width adjustment unit (122). Unlike the first width adjustment unit (121), the second width adjustment unit (122) may have a concave surface positioned in the path of the laser beam (L). The laser beam (L) reaching the second width adjustment unit (122) passes through the second width adjustment unit (122), is refracted to expand in the horizontal direction perpendicular to the reference line (122a). That is, the cross-sectional area of ​​the laser beam (L) emitted from the second width adjustment unit (122) may be larger than the cross-sectional area of ​​the laser beam (L) incident on the second width adjustment unit (122). Since the second width adjustment unit (122) is also an infinite circle like the first width adjustment unit (121), the laser incident on the second width adjustment unit (122) and the laser emitted can be parallel to each other. In summary, the laser beam (L) incident on the width adjustment unit (100) can contract once in the vertical direction, expand once in the horizontal direction, and then be emitted parallel to the direction of incidence. Therefore, a laser beam (L) with an elliptical cross-section in which the vertical direction is the major axis and the horizontal direction is the minor axis can be passed through a pair of width adjustment units (120) to contract the major axis and expand the minor axis, thereby adjusting the laser beam (L) to have a circular cross-section.

[0133] For specific explanation, a cross-sectional view of the laser beam (L) incident on the barrel, a cross-sectional view of the laser beam (L) after passing through the first width adjustment unit (121), and a cross-sectional view of the laser beam (L) after passing through the second width adjustment unit (122) are compared. When comparing the cross-sectional views of the three points, the horizontal axis lengths x1, which is the horizontal axis length of the laser beam (L) incident on the barrel, and x2, which is the horizontal axis length of the laser beam (L) after passing through the first width adjustment unit (121), have the same value, while x3, which is the horizontal axis length of the laser beam (L) after passing through the second width adjustment unit (122), may have a value greater than x1 and x2. Additionally, the length of the vertical axis y1, which is the length of the vertical axis of the laser beam (L) incident on the barrel, has the largest value, and y2, which is the length of the vertical axis of the laser beam (L) that has passed through the first width adjustment unit (121), can have the same value as y3, which is the length of the vertical axis of the laser beam (L) that has passed through the second width adjustment unit (122).

[0134] According to another embodiment, the first width adjustment unit (121) and the second width adjustment unit (122) have different shapes and / or materials, and thus the amount of change in the cross-sectional area of ​​the laser beam (L) when passing through the first width adjustment unit (121) may be different from the amount of change in the cross-sectional area of ​​the laser beam (L) when passing through the second width adjustment unit (122).

[0135] Since the horizontal axis length of the laser beam (L) emitted through the above process is x3 and the vertical axis length is y3, the laser beam (L) with an elliptical cross section can be adjusted into a laser beam (L) with a circular cross section by adjusting x3 and y3 to have the same value.

[0136] Although the drawing only illustrates the case where the reference lines (121a, 122a) of the first width adjustment unit (121) and the second width adjustment unit (122) are perpendicular to each other, it is obvious that the laser processing device according to another embodiment can also adjust the angles of the reference lines (121a, 122a) of the first width adjustment unit (121) and the second width adjustment unit (122) in various ways, just like the laser processing device according to one embodiment.

[0137] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing the technical concept or essential features thereof. Therefore, the embodiments described above should be understood as being restrictive in all respects and not limiting. Explanation of the symbols

[0138] LS: Laser light source L: Laser beam 100: Width adjustment section 121: First width adjustment unit 122: Second width adjustment unit 200: Scanner unit 300: F Theta lens

Claims

Claim 1 A laser processing device comprising: a laser light source; a width adjustment unit for adjusting the width of a laser beam emitted from the laser light source; and a scanner unit for adjusting the irradiation direction of a laser beam passing through the width adjustment unit; wherein the width adjustment unit comprises a first width adjustment unit and a second width adjustment unit arranged in overlap with the direction of travel of the laser beam, and the focal length of the first width adjustment unit and the second width adjustment unit is 20,000 mm or more. Claim 2 In claim 1, the laser processing device wherein the first width adjustment unit and the second width adjustment unit have the same shape and are made of the same material. Claim 3 A laser processing device according to claim 2, further comprising an F-theta lens that focuses the laser beam passing through the scanner to an area to be processed. Claim 4 In claim 2, the first width adjustment unit and the second width adjustment unit each include a reference line, and the first width adjustment unit and the second width adjustment unit adjust the cross-section of an incident laser beam in a direction perpendicular to the reference line. Claim 5 In claim 4, the first width adjustment unit and the second width adjustment unit each include a convex surface and a concave surface, and the curvatures of the convex surface and the concave surface are different from each other, in a laser processing device. Claim 6 A laser processing device according to claim 5, wherein the convex surfaces of the first width adjustment unit and the second width adjustment unit are both arranged in a direction in which a laser beam is incident on the width adjustment unit, and the laser beam passes through the first width adjustment unit and the second width adjustment unit and contracts in a direction perpendicular to the reference line of the first width adjustment unit and the reference line of the second width adjustment unit. Claim 7 A laser processing device according to claim 5, wherein the radius of curvature of the convex surface is 23 to 24 mm, the radius of curvature of the concave surface is 19 mm to 21 mm, and the thickness of the first width adjustment unit and the second width adjustment unit is 9 mm to 11 mm. Claim 8 In claim 4, the width adjustment unit includes an opening, and the laser processing device is capable of adjusting the arrangement of the first width adjustment unit and the second width adjustment unit through the opening. Claim 9 A laser processing device according to claim 8, wherein the laser beam passes through the first width adjustment unit and the second width adjustment unit and contracts in a direction perpendicular to the reference line of the first width adjustment unit and the reference line of the second width adjustment unit, and can adjust the cross-section of the laser beam incident on the width adjustment unit by adjusting the arrangement of the first width adjustment unit and the angle between the reference line of the first width adjustment unit and the reference line of the second width adjustment unit. Claim 10 A laser processing device according to claim 2, further comprising a beam expander between the laser light source and the width adjustment unit that increases the diameter of the laser beam overall. Claim 11 A laser processing device according to claim 10, wherein the cross-sectional area in the direction perpendicular to the direction of travel of the laser beam emitted from the beam expander is smaller than the cross-sectional area of ​​the first width adjustment unit and the second width adjustment unit. Claim 12 In claim 1, the first width adjustment unit and the second width adjustment unit are laser processing devices having different shapes. Claim 13 A laser processing device according to claim 12, wherein the first width adjustment unit and the second width adjustment unit each include a convex surface and a concave surface, and the curvatures of the convex surface and the concave surface are different from each other. Claim 14 A laser processing device according to claim 13, wherein the convex surface of the first width adjustment unit is positioned in a direction in which a laser beam is incident on the width adjustment unit, and the convex surface of the second width adjustment unit is positioned in a direction in which a laser beam is emitted from the width adjustment unit. Claim 15 In claim 13, the first width adjustment unit and the second width adjustment unit each include a reference line, and the first width adjustment unit and the second width adjustment unit adjust the cross-section of an incident laser beam in a direction perpendicular to the reference line. Claim 16 A laser processing device according to claim 15, wherein the first width adjustment unit contracts the cross-section of the laser beam passing through the first width adjustment unit in a direction perpendicular to the reference line of the first width adjustment unit, and the second width adjustment unit expands the cross-section of the laser beam passing through the second width adjustment unit in a direction perpendicular to the reference line of the second width adjustment unit. Claim 17 A laser processing method comprising: a step of measuring the cross-section of a laser beam; a step of analyzing the cross-section of the laser beam to determine the direction and ratio of the major axis and the minor axis; and a step of arranging the first width adjustment unit and the second width adjustment unit so as to overlap the direction of travel of the laser beam by adjusting the relative angle between the reference line of the first width adjustment unit and the second width adjustment unit and the major axis and the minor axis of the laser beam, taking into account the direction and ratio of the major axis and the minor axis of the laser beam. Claim 18 A laser processing method according to claim 17, further comprising the step of emitting the laser beam toward the first width adjustment unit and the second width adjustment unit to adjust the cross-section of the laser beam after the step of arranging the first width adjustment unit and the second width adjustment unit. Claim 19 A laser processing method according to claim 18, further comprising the step of processing an object using the laser beam after the step of adjusting the cross-section of the laser beam. Claim 20 A laser processing method according to claim 17, further comprising the step of positioning a scanner unit so as to overlap with the direction of travel of the laser beam.

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