KR102199350B1 - Line beam optic and apparatus for laser lift off using the same - Google Patents

Abstract

A line beam optical system according to the present invention comprises: a beam generating unit; an optical fiber unit for emitting a laser beam output from the beam generating unit in the form of a flat-top beam; and a beam expander which expands an output distribution of the flat-top beam emitted from the optical fiber unit and emits the beam in the form of a line beam having a high aspect ratio. The numerical aperture of the laser beam includes a first numerical aperture which is a numerical aperture of the laser beam transmitted to the optical fiber unit, a second numerical aperture which is a numerical aperture of the laser beam transmitted to the beam expander, and a third numerical aperture which is the numerical aperture of the laser beam transmitted to the beam expander. The third numerical aperture satisfies an equation. The output distribution of the laser beam emitted from the beam expander maintains a predetermined value and is transmitted to an object in the form of a line beam. According to the equation, NA_3=third numerical aperture, constant k=0.43, S=end slope of laser power distribution, and H=laser homogeneity.

Description

Line beam optical system and laser lift-off device including the same TECHNICAL FIELD [LINE BEAM OPTIC AND APPARATUS FOR LASER LIFT OFF USING THE SAME}

The present invention relates to a line beam optical system and a laser lift-off device including the same.

As the technology advances, the stability and output of the laser beam have improved, and the range of use is expanding to the process of processing semiconductor materials. In particular, in order to form a device such as a light emitting diode (LED: Light Emittiing Diode), there are many processes of separating a film on a substrate using a laser beam. A typical equipment used in this process is laser lift off (LLO: Laser Lift Off) equipment. The laser lift-off process is a process in which a laser beam is irradiated onto a substrate to dissolve the adhesion and separate the substrate from the film. In other words, laser lift-off involves removing or separating one or more selected layers of material by damage, vaporization.

For example, in a manufacturing process of a semiconductor light emitting device formed of a GaN (gallium nitride) compound semiconductor, a GaN compound crystal layer formed on a sapphire substrate is peeled off by irradiating a laser beam from the back surface of the sapphire substrate. That is, by irradiating the GaN layer formed on the sapphire substrate with laser light on the back surface of the sapphire substrate, GaN forming the GaN layer is decomposed, and the GaN layer is peeled from the sapphire substrate.

The form of the laser beam used herein may be in various forms such as a Gaussian beam and a flat top beam. At this time, in the case of a Gaussian beam, there is a problem in that uniform energy cannot be applied to the object because there is a difference in energy between the central portion and the outer portion of the beam. That is, there is a problem in that it is difficult to irradiate a laser beam having a uniform energy size over the entire area of the substrate or film in order to separate the substrate and the film.

Republic of Korea Patent Publication No. 10-1160158 (2012.06.20.)

An embodiment of the present invention is a line beam that forms a laser beam generated from a beam generator into a flat top beam through an optical fiber unit, and controls the output distribution and area of the laser beam through control of the numerical aperture and irradiates it in a line beam form. An object of the present invention is to provide an optical system and a laser lift-off device including the same.

Another embodiment of the present invention is to provide a line beam optical system capable of separating a substrate and a film by applying uniform energy to a substrate and a film through a line beam having a high aspect ratio, and a laser lift-off device including the same. The purpose.

The technical problem to be achieved by the present invention is not limited to the technical problems mentioned above, and other technical problems that are not mentioned can be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. There will be.

을 만족하며,

이되, 상기 빔 익스팬더로부터 발산되는 상기 레이저 빔의 출력분포가 기 결정된 수치를 유지하며 라인 빔 형태로 대상물에 전달되는 라인빔 광학계를 제공한다.(NA₃ = 제3개구수, 상수 k = 0.43, S = 레이저 출력분포의 단부 경사도, H = 레이저 균질성)According to an embodiment of the present invention, a beam generator; An optical fiber unit for irradiating the laser beam output from the beam generating unit in the form of a flat-top beam; And a beam expander that enlarges the output distribution of the flat top beam irradiated from the optical fiber unit and irradiates it in the form of a line beam having a high aspect ratio, wherein the numerical aperture of the laser beam is determined according to a section, and the optical fiber has a numerical aperture of the optical fiber. A first numerical aperture that is a numerical aperture of the laser beam delivered to the negative, a second numerical aperture that is a numerical aperture of the laser beam delivered to the beam expander, and a third numerical aperture that is a numerical aperture of the laser beam delivered to the beam expander Including, the third numerical aperture formula

Satisfying

However, the output distribution of the laser beam emitted from the beam expander maintains a predetermined value and provides a line beam optical system that is transmitted to the object in the form of a line beam. (NA ₃ = number of apertures, constant k = 0.43, S = end slope of laser power distribution, H = laser homogeneity)

In addition, the optical fiber unit may include a core portion and a covering portion surrounding the core portion, and may provide a line beam optical system having a square cross section of the core portion.

In addition, it is possible to provide a line beam optical system in which the first numerical aperture, the third numerical aperture, and the second numerical aperture are sequentially decreased.

In addition, between the fiber portion and the beam expander, a collimator (collimator) for diverging by uniformly adjusting the cross section of the flat top beam; And a condenser for condensing the flat top beam.

In addition, the beam generator may provide a line beam optical system that irradiates an ultraviolet (UV) laser beam.

In addition, it is possible to provide a line beam optical system further comprising: a light adjusting unit including one or more lenses to adjust the length, shape, or direction of the line beam irradiated from the beam expander.

In addition, a line beam optical system may be provided in which a plurality of the optical fibers are spaced apart from each other so that the flat top beams irradiated from each of the optical fibers are overlapped with each other by a predetermined distance, thereby extending the entire length of the flat top beam.

According to an embodiment of the present invention, a beam generator; An optical fiber unit for irradiating the laser beam output from the beam generating unit in the form of a flat-top beam; And a beam expander that enlarges the flat top beam irradiated from the optical fiber unit and irradiates it in the form of a line beam having a high aspect ratio.

According to an embodiment of the present invention, a laser lift-off device including the line beam optical system according to any one of claims 1 to 8 is provided.

According to an exemplary embodiment of the present invention, a line beam having a high aspect ratio may be formed in the form of a flat top beam having a large aspect ratio.

In addition, the laser beam generated by the beam generator may be formed into a flat top beam through an optical fiber unit, and the output distribution and area of the laser beam may be controlled through the control of the numerical aperture, thereby irradiating in the form of a line beam.

In addition, by applying uniform energy to the substrate and the film through a line beam having a high aspect ratio, the film can be separated from the substrate.

1 is a schematic diagram of a line beam optical system according to an embodiment of the present invention
2 is a view showing a cross-section of an optical fiber unit according to an embodiment of the present invention
3 is a schematic diagram showing that a laser beam is transmitted through a beam expander as an embodiment of the present invention
4 is a view showing an output distribution of a laser beam in the form of a flat top beam emitted through a line beam optical system according to an embodiment of the present invention
5 to 8 are schematic diagrams showing that the length of a beam is adjusted through a plurality of optical fibers according to an embodiment of the present invention
9 is a schematic diagram of a line beam optical system according to another embodiment of the present invention
10 and 11 are schematic diagrams showing a laser lift-off device including a line beam optical system according to an embodiment of the present invention

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, this is only an example and the present invention is not limited thereto.

In describing the present invention, when it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

The technical idea of the present invention is determined by the claims, and the following embodiments are only one means for efficiently describing the technical idea of the present invention to those of ordinary skill in the art.

1 is a schematic diagram of a line beam optical system 1 according to an embodiment of the present invention.

Referring to FIG. 1, the line beam optical system 1 includes a beam generating unit 10, an optical fiber unit 20, a connector unit 30, a collimator 40, a condensing unit 50, and a beam expander 60. can do.

The beam generator 10 may output a laser beam. It is possible to output the laser beam required to irradiate the beam to the object to be processed. The laser beam output from the beam generator 10 may be an ultraviolet (UV) laser beam. As an example, the beam generator 10 may be formed of a UV laser having a wavelength of 359 nm and a UV laser having a wavelength of 343 nm. However, the present invention is not limited thereto, and the beam generator 10 may be formed of various types of lasers capable of outputting a laser beam other than a UV laser.

The laser beam output from the beam generator 10 may be irradiated to the optical fiber unit 20.

The optical fiber unit 20 may shape a laser beam generated from the beam generating unit 10. Here, shaping refers to shaping the output distribution (cross-sectional area and energy density of the laser beam) including the cross-sectional shape of the laser beam transmission direction, and the cross-sectional shape of the laser beam generated from the beam generator 10 can be formed. There is. For example, the optical fiber unit 20 may shape the cross section of the laser beam into a square shape, and form the laser beam into a flat-top beam for irradiation.

That is, the optical fiber unit 20 may selectively determine the direction of the laser beam, a shape to be processed on the object through the laser beam, and an output distribution of the laser beam. A detailed description of the optical fiber unit 20 will be described later in FIG. 2.

Here, the flat top beam is a beam having a uniform energy distribution. Accordingly, an object (not shown) to which the flat top beam is irradiated is affected by energy of a uniform size. Therefore, in the case of using a flat top beam, laser processing of uniform quality can be performed, thereby increasing processing completion. In other words, since the laser beam is formed in a flat-top beam format, the surface of the processed part of the object can be smoothly finished and the thermal effect on the periphery of the processed part can be minimized. Accordingly, the degree of processing completion of the object can be increased.

The connector unit 30 may connect the optical fiber unit 20 and the collimator 40. The connector may be for guiding the laser beam transmitted from the optical fiber unit 20 to the collimator 40. To this end, one side of the connector may be connected to the optical fiber unit 20 and the other side may be connected to the collimator 40.

The collimator 40 may transform the laser beam emitted from the laser into a parallel beam and transmit it in a parallel state.

Specifically, the laser beam output from the beam generating unit 10 passes through the optical fiber unit 20 and is shaped into a flat top beam, and the flat top beam irradiated from the optical fiber unit 20 is transmitted to the collimator 40. I can.

The collimator 40 may adjust the flat top beam irradiated from the optical fiber unit 20 to be parallel and enlarged. That is, the collimator 40 can be formed in a uniform cross section (ie, a flat cross section) in the irradiation direction in which the flat top beam is to be irradiated. The flat top beam passing through the collimator 40 is transmitted to the condensing unit 50 so that the laser can be concentrated.

The flat top beam concentrated by the condensing unit 50 may be irradiated by the beam expander 60.

The beam expander 60 may expand the flat top beam irradiated from the condenser 50 to irradiate the beam in the form of a line beam having a high aspect ratio.

The area of the laser beam reaching the beam expander 60 can be increased as it diverges from the beam expander 60. Of course, it does not have to be increased, and the rate of increase or whether it is increased can be selectively determined. This selective determinant is related to the numerical aperture, which will be described later in FIGS. 3 and 4.

In this embodiment, it is shown that the flat top beam is irradiated in the form of a line beam through the beam expander 60.

Specifically, when the laser reach area is increased, the laser of the flat-top beam type increases the distance to be irradiated while maintaining the flat-top beam type, thereby forming a line beam type. In this case, since the output distribution of the laser per the same area decreases, when the reaching area of the laser increases, the output of the laser irradiated from the beam generator 10 may be adjusted to increase. That is, even when the area to which the laser emitted from the beam expander 60 reaches is increased, the laser output from the beam generator 10 may be adjusted and output so that the output distribution of the laser per unit area can be maintained.

Meanwhile, the control of the output distribution per unit area relative to the arrival area of the laser beam may be controlled by a controller (not shown). The control is based on, for example, a distance to an object, a divergence angle adjusted to be emitted from the beam expander 60, and the current setting output of the laser beam as basic information, the laser emitted from the beam expander 60 is Since the area to be reached can be predicted, it is possible to adjust the output of the laser beam to a predetermined level. In addition to the above-described basic information, various information may be used to adjust the laser beam output.

In this way, the beam expander 60 may convert and output a thin parallel beam of a flat top beam into a thick parallel beam of light. That is, when the flat top beam passes through the beam expander 60, a line beam having an increased aspect ratio of the flat top beam may be output.

At this time, the beam expander 60 is composed of one or more lenses (not shown), and the flat top beam may be enlarged according to the arrangement of the lenses, the shape or type of the lenses, and the distance between the lenses.

In summary, in the line beam optical system 1 according to an embodiment of the present invention, the laser beam output from the beam generator 10 is formed into a flat top beam in the optical fiber unit 20, and the flat top beam is a beam expander. The flat top beam may be expanded while passing through 60 to output a line beam having a high aspect ratio.

2 is a view showing a cross-section of the optical fiber unit 20 according to an embodiment of the present invention.

Referring to FIG. 2, as described above, the laser beam output from the beam generator 10 may be formed into a flat top beam while passing through the optical fiber unit 20. The optical fiber unit 20 may include a core unit 201 and a covering unit 202.

The core part 201 may shape the laser beam output from the beam generating part 10. Specifically, the laser beam output from the beam generator 10 passes through the core portion 201, and a cross-sectional shape of the laser beam may be formed according to the shape of the core portion 201. That is, the output distribution (cross-sectional area and energy density of the laser beam) of the beam may be determined according to the cross-sectional shape of the core part 201.

The cross section of the core part 201 may be formed in a square shape. In this case, the laser beam may be irradiated to the object to be processed in a square shape. When the core portion 201 having a square cross section is used, a flat top beam can be generated without a separate device for shaping the output distribution of the laser beam.

However, the core portion 201 is not limited to being formed in a rectangular cross section, and may be formed in various cross sections. For example, the core part 201 may be formed in various shapes such as a circle, an ellipse, and a polygon. In this case, when the laser beam cannot be formed into a flat top beam through the shape of the core part 201, a separate device for converting the laser beam into a flat top beam shape may be provided.

The covering portion 202 may perform a function of protecting the core portion 201. For example, it may be formed of a material having waterproof, soft and rigid materials.

3 is a schematic diagram showing that a laser beam is transmitted through a beam expander according to an embodiment of the present invention.

Referring to FIG. 3, during a process in which the laser beam generated by the beam generator 10 is transmitted through the beam expander 60, the numerical aperture (NA) of the laser beam may be determined within a predetermined range.

Here, the numerical aperture (NA) is a value representing the angle at which the laser diverges, and is determined by the ratio of the length z in the transmission direction of the laser beam and the length h in the vertical direction from the transmission direction. Specifically, the numerical aperture indicates the condensing ability of light, and light can be incident within a wide range of incident angles.

The line beam optical system 1 may determine the size of the laser beam spot according to the distance relationship with the object, or the size of the spot by adjusting the laser beam numerical aperture according to the output size. That is, the numerical aperture may be one of the determining factors of the laser beam spot size and the laser beam output transmitted to the object.

The numerical aperture in the present invention can specify a position on the laser transmission path. When the numerical aperture of the specified position is specified by the first number of apertures (NA1), the second number of apertures (NA2), and the number of third apertures (NA3), respectively, the divergence location at which the laser is finally emitted is the third aperture number ( It can be called NA3). That is, in order to determine the third opening number NA3 at the time of divergence, the first opening number NA1 and the second opening number NA2 may be controlled to a specific numerical aperture.

The length z in the delivery direction becomes the denominator factor, and the length h in the vertical direction becomes the numerator factor. That is, the numerical aperture (NA) is determined by the numerator and denominator values. Accordingly, the larger the numerical aperture (NA) is, the larger the length h in the vertical direction is, and the smaller the numerical aperture (NA), the relatively large length z is in the transmission direction.

The numerical aperture (NA) of the present embodiment can describe three conditions as an example. The numerical aperture (NA) representing the degree of divergence and convergence of the laser beam may be determined within the range of 0.1 to 0.3. (Preferably can be 0.22). In addition, the second opening number NA2 delivered to the beam expander 60 may be determined within a range of 0.02 to 0.06 (preferably 0.03 or 0.05). In addition, the third opening number NA3 emitted by the beam expander 60 may be determined within a range of 0.03 to 0.12 (preferably 0.1 or less).

However, each numerical aperture (NA) may be formed so that the first, third, and second openings NA1, NA3, and NA2 gradually decrease. That is, the relationship between the first number of openings (NA1)> the number of third openings (NA3)> the number of second openings (NA2) may be satisfied. Even in this process, the cross-sectional shape and power distribution of the laser can be maintained.

4 is a diagram illustrating an output distribution of a flat top beam type laser beam emitted through a line beam optical system according to an embodiment of the present invention.

Referring to FIG. 4, in the case of the third aperture NA3 described above, it may be determined within a range satisfying the following equation.

NA ₃ = 3rd opening, constant k = 0.43, S = end slope of laser power distribution, H = laser homogeneity

일 수 있다.Preferably,

Can be

Specifically, S (Edge Stiffness, the end slope of the laser output distribution) is one of the criteria for evaluating the flat top, and the intensity from the bottom (lowest part) to the flat part (TOP) of the graph shown in FIG. 4 ( Intensity) represents the slope, and H (homogeneity, laser homogeneity) is one of the criteria for evaluating the flat top, and represents the intensity fluctuation at the top.

Further, referring to Table 1 below, the relationship between (Homogeniety)∝?1/(Beam size)?^2 (inverse proportional relationship between H and beam size) and (Edge Stiffness)∝?(Beam size)?^4 It can be seen that (a proportional relationship between S and beam size) is established. That is, the relationship of S∝H^2 can be established.

The table below is a table listing the experimental values, and the experimental conditions are H(Homogeneity) = 85% or more, S(Edge Stiffness) = 5% or less, the first number of openings (NA1) = 0.22, the second number of openings (NA2) = 0.03, This is the result of the experiment under the condition of the third opening number (NA3) = 0.05.

As shown in Table 1 above, since H (homogeneity) and S (edge stiffness) values are values at the time point when they are transmitted to the object to be processed, it can be transmitted while maintaining the specific quality of the laser. The specific quality requirements are S (Edge Stiffness) of 5% or less and H (Homogeneity) of 85% or more.

의 관계가 성립될 수 있다.In addition, referring to Table 2 below, the relationship of (Homogeniety)∝1/(?3rd number of openings) ⁴ (inverse relationship between H and the 3rd number of openings (NA3)) and (Edge Stiffness)∝(3rd number of openings ) It can be seen that the relationship of ² (a proportional relationship between S and the third number of openings (NA3)) is established. In other words ,

The relationship of can be established.

That is, since homogeniety is proportional to 1/(third number of ports) ⁴ and 1/(Beam size) ² , (third number of ports) ² is proportional to (Beam size).

As described above, when the value of S (Edge Stiffness), which is a specific quality requirement, exceeds 5%, it may cause a thermal effect around the laser processing unit, resulting in a decrease in strength and cracking of the processed product. In addition, when the H (homogeneity) value is lowered to less than 85%, the flatness may decrease, and the processed surface may not be uniform. This phenomenon can be more pronounced than when attempting to do non-penetrating laser processing.

The table below is a table listing the experimental values, and the experimental conditions are the results of experiments under the conditions of H(Homogeneity) = 85% or more, S(Edge Stiffness) = 5% or less, and the beam size of a square section = 60mm in width and 60mm in length.

In addition, through FIG. 4(a), H(Homogeneity)=(1-(I_max-I_min)/(I_max+I_min))×100(%) can be seen, and through FIG. 4(b), S(Edge Stiffness) )=((D_(10%)-D_(90%))/D_(10%) )×100(%).

5 to 8 are schematic diagrams showing that the length of a beam is adjusted through a plurality of optical fibers according to an embodiment of the present invention.

5 to 8, the line beam optical system 1 may include a plurality of optical fibers 20. By disposing a plurality of optical fibers 20 in parallel, it is possible to increase the length of the irradiated flat top beam (that is, the width of the flat top beam).

First, referring to FIG. 5, the line beam optical system 1 includes a plurality of beam generators 10, an optical fiber part 20, a connector part 30, a collimator 40, a condensing part 50, and a beam expander 60. ) Can be included. Hereinafter, each configuration is described as an example in which four are arranged, but the present invention is not limited thereto, and design changes may be made by those skilled in the art.

The laser beam irradiated from each of the plurality of beam generating units 10 passes through each optical fiber unit 20 and may be formed into a flat top beam. Thereafter, the laser beam passing through each optical fiber unit 20 may be output while passing through the connector unit 30, the collimator 40, the condensing unit 50, and the beam expander 60. In this case, the plurality of beam expanders 60 are disposed in parallel and spaced apart at predetermined intervals so that the flat top beams output from each of the beam expanders 60 overlap each other. Accordingly, the flat top beams output from each of the beam expanders 60 overlap each other by a predetermined distance D, so that the length (ie, width) of the finally output flat top beam can be increased.

Here, referring to FIG. 6, a plurality of the beam generator 10 and the optical fiber unit 20 are arranged in parallel, and the connector unit 30, the collimator 40, the condensing unit 50, and the beam expander 60 are One can be placed.

The laser beam irradiated from each beam generating unit 10 passes through the optical fiber unit 20 and is formed into a flat top beam, and a plurality of flat top beams includes a connector unit 30, a remeter 40, While passing through the condensing unit 50 and the beam expander 60, the output may be overlapped.

Here, referring to FIG. 7, a laser beam irradiated from one beam generating unit 10 is diverged to pass through the optical fiber unit 20, and the flat top beam formed by each optical fiber unit 20 is one connector unit. (30), it can pass through the remeter 40, the condensing unit 50 and the beam expander 60. These flat top beams may be output by overlapping a predetermined distance D.

Here, referring to FIG. 8, a laser beam irradiated from one beam generator 10 is diverged to pass through the optical fiber unit 20, and the flat top beams formed in each optical fiber unit 20 are respectively connected to each connector unit. (30), the remeter 40, the condensing unit 50, and the beam expander 60 may pass through and output, respectively. In this case, the flat top beams output from each of the beam expanders 60 may overlap each other by a predetermined distance D with the flat top beams output from the adjacent beam expanders 60.

Therefore, than the length of the flat top beam irradiated only in one fiber portion, the flat top beam output through the plurality of optical fibers 20 is superimposed and output between adjacent flat top beams, so that the length of the flat top beam can be lengthened. have. In this way, the length of the flat top beam can be extended.

As described above, the flat top beam formed by passing through each optical fiber unit 20 is the optical fiber unit 20 before the connector unit 30, the remeter 40, the condensing unit 50, and the beam expander 60. ), may be overlapped while passing through, one connector part 30, remator 40, condensing part 50, and beam expander 60 may be overlapped while passing through, one connector part 30, It may overlap while being output through the remeter 40, the condensing unit 50, and the beam expander 60. The overlapping position of these flat top beams can be adjusted by a person skilled in the art.

9 is a schematic diagram of a line beam optical system 1 according to an embodiment of the present invention.

Referring to FIG. 9, the line beam optical system 1 may further include a light control unit 70. The light control unit 70 may adjust the length, shape, or direction of the line beam irradiated from the beam expander 60. The light control unit 70 may include one or more lenses. For example, the light adjusting unit 70 may be formed of a lens such as a convex lens, a concave lens, a cylinder lens, and a semi-cylinder lens. The angle, direction, or length to which the line beam is irradiated may be adjusted according to the arrangement of the lenses and the distance between the lenses.

10 and 11 are schematic diagrams showing a laser lift-off device 1000 including a line beam optical system 1 according to an embodiment of the present invention.

Referring to FIGS. 10 and 11, a laser lift off apparatus 1000 according to an embodiment of the present invention may include the line beam optical system 1 described above in FIGS. 1 to 9.

Specifically, the laser lift-off devices 1000 and 1000 may separate the film layer 130 attached to the substrate 110 by the adhesive layer 120.

Specifically, the line beam optical system 1 may irradiate a line beam in the form of a flat top beam having a high aspect ratio toward the film layer 130 or the substrate 110 layer.

The film layer 130 may be separated while the adhesive layer 120 is melted by the line beam irradiated from the line beam optical system 1.

Although the exemplary embodiments of the present invention have been described in detail above, those of ordinary skill in the art to which the present invention pertains will understand that various modifications can be made to the above-described embodiments within the scope of the present invention . Therefore, the scope of the present invention is limited to the described embodiments and should not be determined, and should not be determined by the claims to be described later, but also by the claims and equivalents.

1: line beam optical system
10: beam generator
20: optical fiber unit
30: connector part
40: collimator
50: condenser
60: beam expander
70: light control unit
110: substrate
120: adhesive layer
130: film layer
1000: laser lift off device

Claims (9)

A beam generator;
An optical fiber unit for irradiating the laser beam output from the beam generating unit in the form of a flat-top beam; And
Including; a beam expander that expands the output distribution of the flat top beam irradiated from the optical fiber unit and irradiates it in a form of a line beam having a high aspect ratio,
The numerical aperture of the laser beam is a first numerical aperture that is a numerical aperture of the laser beam transmitted to the optical fiber unit, a second numerical aperture that is a numerical aperture of the laser beam emitted by the beam expander, and the beam expander. Including a third numerical aperture that is the numerical aperture of the laser beam emitted by,
The third numerical aperture

Satisfying

However, the output distribution of the laser beam emitted from the beam expander maintains a predetermined value and is transmitted to the object in the form of a line beam.
(NA ₃ = third count, constant k = 0.43,
S = end slope of laser power distribution, H = laser homogeneity)
The method according to claim 1,
The optical fiber portion includes a core portion and a covering portion surrounding the core portion,
A line beam optical system having a square cross section of the core part.
The method according to claim 1,
A line beam optical system in which the first numerical aperture, the third numerical aperture, and the second numerical aperture are sequentially decreased.
The method according to claim 1,
Between the optical fiber unit and the beam expander,
A collimator that uniformly adjusts and diverges the cross section of the flat top beam; And
A line beam optical system including a condensing unit for condensing the flat top beam.
The method according to claim 1,
The beam generator is a line beam optical system that irradiates a UV (ultraviolet) laser beam.
The method of claim 4,
A line beam optical system further comprising: a light adjusting unit including at least one lens to adjust the length, shape, or direction of the line beam irradiated by the beam expander.
The method of claim 6,
A plurality of the optical fiber units are spaced apart,
A line beam optical system in which the flat top beams irradiated from each of the optical fibers are overlapped with each other by a predetermined distance, thereby extending the entire length of the flat top beam.
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