KR101582632B1 - Substrate cutting method using fresnel zone plate - Google Patents

Abstract

A substrate cutting method capable of precisely performing laser machining at high speed is provided. A method for cutting a substrate according to the present invention includes the steps of generating a laser beam from a laser light source, using a Fresnel zone element to split the laser beam into diffracted first beam components including a diverging component and a converging component, Separating a plurality of beam components into a plurality of beam components including a beam component, focusing the plurality of beam components in a straight line along the thickness direction of the substrate to form a plurality of laser focal points, Forming a layer and cutting the substrate. Wherein the laser focuses of the first beam components about the laser focus of the second beam component are symmetrically arranged along the thickness direction of the substrate and the substrate is a tempered glass substrate having at least one surface with an enhancement layer, Is higher than the energy intensity of the second beam component.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a substrate cutting method using a Fresnel zone element,

The present invention relates to a substrate cutting method, and more particularly, to a substrate cutting method for increasing a cutting efficiency.

A method of irradiating a laser beam along a virtual incision line on a substrate for dividing a semiconductor wafer substrate or a substrate of a light emitting device is used. When the substrate is irradiated with a laser beam, the substrate is completely or partially melted along the thickness direction of the substrate by the energy of the laser beam to be cut.

The conventional laser cutting apparatus comprises a laser light source for emitting a laser beam, a transmission optical system for transmitting a laser beam, an objective lens for focusing the laser beam, and a precision stage for moving the workpiece. Since such a laser cutting apparatus generates a laser beam of a single focal length, the processing speed is slow and it is difficult to precisely process the laser beam.

SUMMARY OF THE INVENTION The present invention is directed to providing a substrate cutting method capable of accurately performing laser cutting at high speed.

A laser cutting apparatus according to an embodiment of the present invention includes a laser light source for generating a laser beam, a Fresnel lens for diffracting a part of the laser beam to divide the laser beam into a diffracted first beam component and a diffracted second beam component, And a condenser for focusing the first beam component and the second beam component in a straight line, and a plurality of laser focuses focused in a straight line are arranged along the thickness direction of the workpiece.

The laser light source may generate a pulsed laser with a pulse duration of either picosecond, femtosecond, nanosecond, or a continuous wave laser.

개로 분리시킬 수 있다.The first beam component may comprise a component to be diverged and a component to be converged. The Fresnel zone element may have a diffraction order (m) of 1 or 2, and the laser beam

Can be separated by a dog.

개(여기서 n은 프레넬 영역 소자의 개수)의 빔 성분으로 분리시킬 수 있다.The Fresnel zone element can move back and forth along the traveling direction of the laser beam. The Fresnel area element is composed of a plurality of Fresnel area elements arranged side by side along the traveling direction of the laser beam,

(Where n is the number of Fresnel zone elements).

The condenser includes an objective lens, and a dichroic mirror can be mounted between the Fresnel area element and the condenser. The concentrator may include a stereoscopic scanner and a scanning lens.

A method of cutting a substrate according to an embodiment of the present invention includes the steps of generating a laser beam from a laser light source, generating a laser beam by using a Fresnel area element, the laser beam including a diffracted first beam component and a diffracted second beam component Separating the plurality of beam components into a plurality of beam components, and cutting the substrate by forming a plurality of laser focuses by focusing the plurality of beam components in a straight line along the thickness direction of the substrate using a condenser.

The first beam component comprises a component to be converged and a component to be converged, and the Fresnel zone element may have a diffraction order of 1 or 2. [ A plurality of laser focal points may be continuously formed and the substrate may be automatically cut.

On the other hand, a plurality of laser foci can be formed discontinuously to form a plurality of altered layers inside the substrate. A laser focus is formed so as to be in contact with the surface of the substrate so as to form a machining groove on the surface of the substrate and an external force is applied to the substrate so that the substrate along the plurality of denatured layers It can be broken and cut.

개(여기서 n은 프레넬 영역 소자의 개수)로 분리시킬 수 있다.The plurality of laser foci can be arranged at regular intervals, and the distance between the plurality of laser foci can be changed by adjusting the position of the Fresnel region elements. A plurality of Fresnel zone elements may be provided, and a plurality of Fresnel zone elements may be provided with laser beams

(Where n is the number of Fresnel zone elements).

The laser beam may be a pulsed laser with a pulse duration of either picosecond, femtosecond, nanosecond, or a continuous wave laser.

The laser cutting apparatus of this embodiment generates multi-focus on a workpiece by using a Fresnel region element as a beam splitter. Thus, laser machining can be performed at a higher speed than a laser cutting apparatus that produces a single focus on a workpiece. In addition, workability and machining accuracy can be improved by variously controlling the interval and the energy intensity of the laser focus in accordance with the characteristics of the workpiece.

1 is a configuration diagram of a laser cutting apparatus according to a first embodiment of the present invention.
FIGS. 2A and 2B are schematic diagrams illustrating the operation of a Fresnel region element having a diffraction order of 1 and a Fresnel region element having a diffraction order of 2, respectively.
Figures 3a, 3b and 4 are cross-sectional views of the workpiece shown in Figure 1;
5 is a configuration diagram of a laser cutting apparatus according to a second embodiment of the present invention.
6 is a configuration diagram of a laser cutting apparatus according to a third embodiment of the present invention.
7 is a configuration diagram of a laser cutting apparatus according to a fourth embodiment of the present invention.
8 is a graph showing changes in focal position of the first beam component according to the interval between the Fresnel area element and the condenser in a laser cutting apparatus having one Fresnel area element.
9 is a graph showing changes in focal position of a first beam component according to the interval between the first and second Fresnel zone elements in a laser cutting apparatus having two Fresnel zone elements.
10 is a schematic view showing a substrate cutting process according to the first embodiment of the present invention.
11 is a schematic view showing a substrate cutting process according to a second embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 is a configuration diagram of a laser cutting apparatus according to a first embodiment of the present invention.

1, the laser cutting apparatus 100 of the first embodiment includes a laser light source 10, a beam transfer unit 20, a Fresnel zone element 30, a dichroic mirror 51, and a condenser 40 ).

The laser light source 10 generates a laser beam for processing a workpiece (for example, a semiconductor wafer substrate or a substrate of a light emitting device). The laser beam may be a picosecond or an ultra short pulsed laser with a pulse duration of femtosecond.

The ultrashort pulse laser has a very high energy intensity and can process various kinds of workpieces. There is no physical chemical deformation due to heat diffusion during machining of the workpieces and no reduction in machining accuracy. In addition, byproducts such as laminating particles and craters due to processing are hardly produced, and the step of removing by-products such as ultrasonic cleaning can be omitted.

Ultrathreshold pulsed lasers can process materials with a high heat transfer coefficient or a low light absorption rate, and workpieces with two or more materials mixed together and multi-layer composite materials can be easily processed into a single process . Meanwhile, the laser light source 10 may oscillate other kinds of laser beams other than the above-mentioned ultrashort pulsed laser, for example, a pulsed laser having a pulse duration of nanosecond or a continuous wave laser.

The beam transmission section 20 is located on the path of the laser beam emitted from the laser light source 10. The beam transmitting portion 20 may be composed of various optical devices, for example, a beam expander for increasing the width of the laser beam, an attenuator for adjusting the energy intensity of the laser beam expanded in the beam expander, and the like. In this case, the width and the energy intensity of the laser beam are controlled through the beam transmission unit 20.

The Fresnel zone element 30 is located on the path of the laser beam output from the beam transmission portion 20. [ The Fresnel zone element 30 is a type of multilevel phase relief diffractive optical element (MLPR DOE), which means a lens that adjusts the divergence or convergence of a beam by diffraction, and the theoretical diffraction efficiency eta is calculated by the following equation.

Here, N represents the number of multi-levels of the Fresnel zone element 30, and m represents the diffraction order. Assuming that the diffraction order is 1, the diffraction efficiency? Is simplified as follows.

The diffraction efficiency η is 40.5% for a binary phase lens with N = 2 and the diffraction efficiency η is 81.1% for a quaternary phase lens with N = 4. For an 8-level lens with N = 8, the diffraction efficiency η is 95.0%, and for a 16-level lens with N = 16, the diffraction efficiency η is 98.7%.

Regardless of the number of multilevels, the diffraction efficiency of the Fresnel zone elements is less than 100%. Therefore, the laser beam incident on the Fresnel zone element 30 is incident on the first beam component diffracted by the Fresnel zone element 30 and the second beam component diffracted by the Fresnel zone element 30 without being affected by the Fresnel zone element 30, Beam component. The Fresnel zone element 30 serves as a beam splitter that separates the laser beam into a plurality of beams depending on whether or not the beam is diffracted.

The condenser 40 is provided with a plurality of beam components separated from the Fresnel zone element 30 and focuses the provided plurality of beam components onto the workpiece 60. The condenser 40 may be constituted by a normal objective lens.

The dichroic mirror 51 is disposed between the Fresnel zone element 30 and the condenser 40 to change paths of a plurality of beam components. The dichroic mirror 51 can be coated with a material having a good reflection effect at this wavelength band so as to reflect most of the wavelength band of the applied laser beam. The dichroic mirror 51 is omitted when the Fresnel zone element 30 and the condenser 40 are positioned on a straight line.

The workpiece 60 is located under the condenser 40 and is moved by the precision stage 52. The precision stage 52 may be a two-dimensional stage for moving the workpiece 60 in the x-axis direction and the y-axis direction, or may be a three-dimensional stage capable of adjusting the height.

In the laser cutting apparatus 100 of the first embodiment, the diffraction order of the Fresnel zone element 30 may be 1 or 2. The Fresnel area element 30 having the diffraction order of 1 separates the incident laser beam into three beam components. The Fresnel area element 30 having the diffraction order of 2 separates the incident laser beam into five beam components .

2A is a schematic view showing a Fresnel region element having a diffraction order of 1 and a condenser.

Referring to FIG. 2A, the Fresnel zone element 30 has a plurality of concentric bands, and each band acts as a diffraction grating to cause diffraction of light. The laser beam LB incident on the Fresnel zone element 30 is divided into the first beam component LB1 diffracted through the Fresnel zone element 30 and the second beam component LB2 not diffracted.

At this time, the diffracted first beam component LB1 is composed of a component LB1-1 converged while passing through the Fresnel zone element 30 and a component LB1-2 emitted. In other words, the Fresnel region element 30 works simultaneously with the converging Fresnel region element having the diffraction order greater than zero and the diffusing Fresnel region element having the diffraction order less than zero. The converged component LB1-1 and the divergent component LB1-2 of the first beam component LB1 have the same energy intensity.

The energy ratio of the first beam component (LB1) and the second beam component (LB2) is determined according to the diffraction efficiency of the Fresnel zone element (30). Assuming that the diffraction efficiency of the Fresnel zone element 30 is 50%, the second beam component LB2 has an energy intensity of 50%, and the converged components LB1-1 and LB2 of the first beam component LB1 The divergent components (LB1-2) each have an energy intensity of 25%. The diffraction efficiency of the Fresnel zone element 30 can be appropriately selected in accordance with the energy intensities of the plurality of beam components required for laser processing.

The focal position of the second beam component LB2 not diffracted in FIG. The focal position A1 of the converged component LB1-1 of the first beam component LB1 is located closer to the condenser 40 than that of B and the focal position A2 of the divergent component LB1-2 is smaller than B Is located away from the concentrator 40. As described above, the Fresnel zone element 30 having the diffraction order of 1 separates the incident laser beam into three components, and the three beam components have different focal positions.

2B is a schematic view showing a Fresnel region element having a diffraction order of 2 and a condenser.

Referring to FIG. 2B, a Fresnel zone element 30 having a diffraction order of 2 differs from that of the first embodiment in that the provided laser beam is divided into five beam components, that is, four diffracted first beam components LB1 and one non- Separate into component (LB2). The four diffracted first beam components LB1 have two components LB1-1 and LB1-2 converging at different convergence angles and two components LB1-3 and LB1- 4). The four diffracted first beam components LB1-1, LB1-2, LB1-3, and LB1-4 have the same energy intensity.

And the focus position of the second beam component LB2 not diffracted in FIG. The focal positions of the two beam components LB1-1 and LB1-2 converged among the four first beam components LB1 are denoted by A1 and A2, respectively, and the two beam components LB1-3 and LB1 -4) were represented by A3 and A4, respectively. The five beam components separated by the Fresnel zone element 30 have different focal positions.

으로 표현될 수 있다. 이때 m은 회절 차수를 나타낸다.The number of components of the laser beam separated by the Fresnel zone element 30 is

. ≪ / RTI > Where m represents diffraction order.

Figures 3a and 3b are cross-sectional views of the workpiece shown in Figure 1; FIG. 3A shows a case where the diffraction order of the Fresnel region element is 1, and FIG. 3B shows the case where the diffraction order of the Fresnel region element is 2. FIG.

Referring to FIGS. 1 and 3A and 3B, a condenser 40 focuses a plurality of beam components separated from the Fresnel zone element 30 in a straight line to form a plurality of laser focuses. At this time, the diffracted pluralities of the first beam component and the single diffracted second beam component are different from each other in focal position (see the beam component path of FIGS. 2A and 2B).

3A, A1 and A2 denote the focal positions of the two first beam components diffracted by the Fresnel zone element 30, and B denote the focal positions of the second diffracted beam component. In Fig. 3B, A1, A2, A3 and A4 denote the focal positions of the four first beam components diffracted by the Fresnel zone elements 30 and B denote the focal positions of the second diffracted beam component.

As described above, the focal positions of the plurality of beam components separated by the Fresnel zone element 30 are located on a straight line along the thickness direction of the workpiece 60.

The laser cutting apparatus 100 of this embodiment generates multi-focus on the workpiece 60 by using the Fresnel zone element 30 as a beam splitter. Thus, laser cutting can be performed at a faster rate than laser cutting devices that produce a single focus on a workpiece.

Referring again to FIG. 1, the laser cutting apparatus 100 may include an illumination light source 53, a reflective mirror 54, a CCD camera 55, and a monitor 56. The light emitted from the illumination light source 53 is irradiated to the workpiece 60 through the reflecting mirror 54. The CCD camera 55 photographs the workpiece 60 and the monitor 56 photographs the workpiece 60 by the CCD camera 55 And displays the photographed image information. 1, reference numeral 57 denotes a barrel, and reference numeral 58 denotes a control unit for controlling the laser light source 10, the beam transfer unit 20, the stage 52, and the like.

On the other hand, the Fresnel zone element 30 that generates multiple foci moves back and forth along the advancing direction of the laser beam. For this purpose, the Fresnel zone element 30 may be provided with a uniaxial stage 35. Thereby changing the focal position of the first beam component by varying the distance between the Fresnel zone element 30 and the concentrator 40 to control the divergence and convergence of the diffracted first beam component.

4 is a cross-sectional view of the workpiece shown in Fig. In Fig. 4, the case where the diffraction order of the Fresnel zone element is 1 is shown.

Referring to FIGS. 1 and 4, the focal positions A1 and A2 of the two first beam components are changed in accordance with the change in the position of the Fresnel zone element 30. FIG. I.e., the focal positions A1 and A2 of the two first beam components change with respect to the focal position B of the undiffracted second beam component, and the focal distance between the three separated beam components can be adjusted .

The focal positions A1, A2, A3, and A4 of the four first beam components are changed in accordance with the change of the position of the Fresnel zone element even when the diffraction order of the Fresnel zone element is 2, (See FIG. 3B).

As described above, the laser cutting apparatus 100 of the present embodiment can perform laser cutting at a higher speed than a laser cutting apparatus that generates a single focal point by forming a multi-focal point. Further, by changing the position of the Fresnel zone element 30 and varying the distance between the focuses of a plurality of separated beam components, a laser focus optimized to the characteristics (material, thickness, etc.) of the workpiece 60 is generated So that the cutting performance can be enhanced.

5 is a configuration diagram of a laser cutting apparatus according to a second embodiment of the present invention.

5, the laser cutting apparatus 200 according to the second embodiment is a laser cutting apparatus according to the second embodiment except that the dichroic mirror is omitted and the condenser 401 is composed of the stereoscopic scanner 41 and the scanning lens 42, And has the same configuration as the laser cutting apparatus of the embodiment. The same reference numerals are used for the same members as in the first embodiment, and the following description will mainly focus on the parts different from those of the first embodiment below.

The stereoscopic scanner 41 may be a pair of galvanometer scanners. A galvanometer scanner is a mirror mounted on a rotating shaft of a motor, and scans the laser beam within a certain angle range by mirror rotation. The scanning lens 42 may be composed of an F-theta telecentric lens. As the condenser 401 is configured as a scanning optical system, the laser cutting apparatus 200 can cut the workpiece 60 while scanning the laser beam.

6 is a configuration diagram of a laser cutting apparatus according to a third embodiment of the present invention.

6, the laser cutting apparatus 300 of the third embodiment differs from the laser cutting apparatus 300 of the first embodiment described above except that the Fresnel zone element 301 is composed of two Fresnel zone elements 31, . The same reference numerals are used for the same members as in the first embodiment, and the following description will mainly focus on the parts different from those of the first embodiment below.

개로 분리시키므로

의 초점 분할이 가능하다. 여기서, n은 프레넬 영역 소자(301)의 개수를 나타낸다. The first Fresnel zone element 31 and the second Fresnel zone element 32 are arranged side by side along the traveling direction of the laser beam. A laser beam is irradiated onto each of the Fresnel zone elements 31 and 32

By separating into dogs

Is possible. Here, n represents the number of Fresnel zone elements 301.

When the diffraction order of the first Fresnel zone element 31 and the second Fresnel zone element 32 is 1, the laser cutting apparatus 300 of the third embodiment can separate the focal point of the laser beam into nine. When the diffraction order of the first Fresnel zone element 31 and the second Fresnel zone element 32 is 2, the laser cutting apparatus 300 of the third embodiment can separate the focal point of the laser beam into 25 pieces.

As described above, the laser cutting apparatus 300 of the third embodiment can separate the laser beam into a larger number of laser beams than in the first embodiment, and the plurality of separated beam components are focused by the condenser 40 in the thickness direction of the workpiece 60 It is then focused in a straight line.

At this time, each of the first and second Fresnel zone elements 31 and 32 moves back and forth along the advancing direction of the laser beam. Thus, the focal position of the beam components diffracted by the first and second Fresnel zone elements 31 and 32 can be changed to change the focus distance between the plurality of beam components. Further, the energy intensity of the plurality of beam components separated according to the diffraction efficiencies of the first and second Fresnel zone elements 31 and 32 can be adjusted.

7 is a configuration diagram of a laser cutting apparatus according to a fourth embodiment of the present invention.

7, except that the dichroic mirror is omitted and the condenser 401 is constituted by the stereoscopic scanner 41 and the scanning lens 42, the laser cutting device 400 of the fourth embodiment is the same as the third And has the same configuration as the laser cutting apparatus of the embodiment. Further, the configurations of the stereoscopic scanner 41 and the scanning lens 42 are the same as those described in the second embodiment, and a detailed description thereof will be omitted.

Although FIGS. 1 and 5 to 7 illustrate the transmission type Fresnel area element 30 that transmits a laser beam, the Fresnel area element 30 may be composed of a reflection type Fresnel area element. The reflective Fresnel zone device may be a liquid crystal on silicon (LCOS) device having a liquid crystal or a spatial light modulator of a digital micro-mirror device (DMD) type .

8 is a graph showing changes in focal position of the first beam component according to the interval between the Fresnel area element and the condenser in the laser cutting apparatus of the first and second embodiments having one Fresnel area element. FIG. 8 shows changes in the focal position of the converged beam component. The incident diameter of the laser beam is 5 mm, and the wavelength is 355 nm. The effective focal length of the condenser (objective lens) is 4 mm, and the effective focal length of the Fresnel zone element is 250 mm.

Referring to FIG. 8, the focal position of the first beam component diffracted by the Fresnel zone element varies from about 3.93 mm to about 3.80 mm. On the other hand, the focal position of the second beam component which is not diffracted by the Fresnel zone element is 4 mm, and the fixed position is maintained. When the distance between the Fresnel zone element and the condenser changes from 20 mm to 180 mm, the distance between the focal points of the first and second beam components varies from about 70 μm to 200 μm.

FIG. 9 is a graph showing changes in the focal position of the first beam component according to the interval between the first and second Fresnel zone elements in the laser cutting apparatuses of the third and fourth embodiments having two Fresnel zone elements.

FIG. 9 shows changes in focal position of beam components converged while passing through the first and second Fresnel zone elements. The incident diameter of the laser beam is 5 mm, and the wavelength is 355 nm. The effective focal length of the condenser (objective lens) is 4 mm, and the effective focal lengths of the first and second Fresnel zone elements are 250 mm and 1000 mm, respectively. The distance between the first Fresnel area element and the second Fresnel area element was adjusted while the distance between the first Fresnel area element and the condenser was fixed at 100 mm.

Referring to Fig. 9, the focal position of the first beam component diffracted by the first and second Fresnel zone elements varies from about 3.847 mm to about 3.60 mm. When the distance between the first Fresnel zone element and the second Fresnel zone element changes within a range of 700 mm or less, the focus position of the first beam component varies within a range of 0.247 mm (247 μm) or less.

Next, a substrate cutting method using the above-described laser cutting apparatus will be described.

10 is a schematic view showing a substrate cutting process according to the first embodiment of the present invention.

10, the substrate cutting method of the first embodiment includes a first step of generating a laser beam from a laser light source, a second step of separating the laser beam into a plurality of beam components using a Fresnel zone element, And a third step of cutting the substrate 61 by focusing a plurality of beam components in a straight line along the thickness direction of the substrate 61 to form a plurality of laser focal points.

In the third step, a plurality of laser focuses A1, B and A2 are formed discontinuously with a distance therebetween. A plurality of altered layers 71 are formed in the substrate 61 by the energy of the laser beam for each focus position do. At this time, any one laser focus A2 located at the outermost one of the plurality of laser focuses A1, B, A2 is formed to contact the surface of the substrate 61 to form a machining groove 72 on the surface of the substrate 61 can do. FIG. 10 shows an example in which one Fresnel region element having a diffraction order of 1 is applied.

When an external force is applied to the substrate 61 described above, the substrate 61 can be broken and cut along the plurality of altered layers 71 by starting to break from the grooves 72. A plurality of laser foci (A1, B, A2) are equally spaced, and a plurality of laser beams can have the same or very similar energy intensity.

Assuming that the Fresnel area element has a diffraction efficiency of 66.6%, the three beam components can have extremely similar energy intensities. The distance between the three laser focuses A1, B, and A2 can be easily changed by adjusting the position of the Fresnel area element.

Although the illustration is omitted, when the diffraction order of the Fresnel zone element is 2, the laser beam is separated into five beam components. The laser focus of the five beam components is equidistant, and the five beam components can have the same or very similar energy intensities. For example, if the diffraction efficiency of the Fresnel zone element is 80%, then the five beam components can have the same energy intensity.

On the other hand, the energy intensity of the first beam component may be different from the energy intensity of the second beam component depending on the diffraction efficiency of the Fresnel zone element. The energy intensity of the first beam component may be higher or lower than the energy intensity of the second beam component.

The substrate 61 may be a tempered glass substrate having an enhancement layer. When the reinforcing layer is present inside the substrate 61, it is possible to increase the energy intensity of the second beam component indicated by the focus position B by applying a Fresnel region element having a low diffraction efficiency. Conversely, when the reinforcing layer is present on the surface of the substrate 61, it is possible to increase the energy intensity of the first beam component indicated by the focus positions A1 and A2 by applying a Fresnel region element having a high diffraction efficiency.

In both of the above cases, higher energy is applied to the enhancement layer to more easily break the enhancement layer.

11 is a schematic view showing a substrate cutting process according to a second embodiment of the present invention.

11, the substrate cutting method of the second embodiment is similar to the above-described method except that the plurality of laser foci A1, A2, B, A3, A4 are continuously formed and the substrate 61 is automatically cut without an external force Is the same as the substrate cutting method of the first embodiment. FIG. 11 shows an example in which one Fresnel area element having a diffraction order of 2 is applied.

A plurality of laser focuses A1, A2, B, A3, and A4 are continuously formed on the substrate 61 so that the plurality of altered layers are formed to be in contact with each other. Therefore, in the second embodiment, the substrate 61 can be automatically cut without applying an external force to the substrate 61. [ Since the size of the laser focus can be variously adjusted according to the specifications of the condenser, it is possible to form a plurality of laser focuses continuously.

According to the above-described substrate cutting method, it is possible to cut the substrate at a high speed by forming a laser multi-focal point along the thickness direction of the substrate inside the substrate. In addition, it is possible to effectively improve workability and machining accuracy by variously adjusting the interval and the energy intensity of the laser focus in accordance with the characteristics of the substrate.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

100, 200, 300, 400: laser cutting device
10: laser light source 20: beam transmission part
30, 301: Fresnel region element 31: First Fresnel region element
32: second Fresnel zone element 40: condenser
51: Dichroic mirror 60: Workpiece
61: substrate

Claims (16)

delete delete delete delete delete delete delete delete Generating a laser beam from a laser light source;
Separating the laser beam into a plurality of beam components including a diffracted first beam components including a divergent component and a convergent component and a second beam component not diffracted using a Fresnel zone element; And
And focusing the plurality of beam components in a straight line along the thickness direction of the substrate using a condenser to form a plurality of laser focuses and forming a plurality of altered layers in the substrate to cut the substrate, ,
Wherein laser focuses of the first beam components are symmetrically arranged along a thickness direction of the substrate, centering on a laser focus of the second beam component,
Wherein the substrate is a tempered glass substrate having a reinforcing layer formed on at least one surface thereof,
Wherein the energy intensity of each of the first beam components is higher than the energy intensity of the second beam component. 10. The method of claim 9,
Wherein at least one of the laser focuses of the first beam components is in contact with the enhancement layer to form a machining groove in the enhancement layer and the substrate is fractured and cut along the plurality of denaturation layers from the machining groove by an external force, Cutting method. 10. The method of claim 9,
Wherein the plurality of laser focal points are continuously formed so that the substrate is automatically cut without an external force. Generating a laser beam from a laser light source;
Separating the laser beam into a plurality of beam components including a diffracted first beam components including a divergent component and a convergent component and a second beam component not diffracted using a Fresnel zone element; And
And focusing the plurality of beam components in a straight line along the thickness direction of the substrate using a condenser to form a plurality of laser focuses and forming a plurality of altered layers in the substrate to cut the substrate, ,
Wherein laser focuses of the first beam components are symmetrically arranged along a thickness direction of the substrate, centering on a laser focus of the second beam component,
Wherein the substrate is a tempered glass substrate having a reinforcing layer formed therein,
Wherein the energy intensity of the second beam component is higher than the energy intensity of each of the first beam components. 13. The method of claim 12,
Wherein at least one of the laser focuses of the first beam components is in contact with a surface of the substrate to form a machining groove in the surface of the substrate and the substrate is fractured and cut along the plurality of denaturation layers / RTI > delete 13. The method of claim 12,
Wherein the plurality of laser focal points are continuously formed so that the substrate is automatically cut without an external force. The method according to claim 9 or 12,
Wherein the laser beam is a pulse laser having a pulse duration of one of picosecond, femtosecond, and nanosecond, or a continuous wave laser.

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