WO2017115974A1

WO2017115974A1 - Lens optical system and laser processing apparatus comprising same

Info

Publication number: WO2017115974A1
Application number: PCT/KR2016/009758
Authority: WO
Inventors: 박정래; 정웅희
Original assignee: (주)이오테크닉스
Priority date: 2015-12-28
Filing date: 2016-09-01
Publication date: 2017-07-06
Also published as: TW201722600A; KR20170077597A; TWI626103B; KR102046932B1

Abstract

A lens optical system and a laser processing apparatus comprising the same are disclosed. The disclosed lens optical system comprises: a body part including a first surface on which light is incident and a second flat surface opposite to the first surface; a circular lens part provided at the center of the second surface; and at least one annular lens part provided on the first surface so as to surround the circular lens part. Here, the circular lens part and the at least one annular lens part may have different radii of curvature, thereby forming a plurality of light-converging points spaced apart from each other along a traveling direction of the light.

Description

Lens optical system and laser processing apparatus including the same

The present invention relates to a lens optical system and a laser processing apparatus including the same.

In the conventional laser processing process, the laser beam is a line-shaped beam whose focusing point is formed in one direction on the processing surface of the object to be processed, and its depth has a constant structure. This processing method has the advantage of machining a large machining area to the same depth. However, such a processing method has a disadvantage in that it is difficult to be applied to a field that needs to shorten the machining time by reducing the number of machining, for example, cutting of a transparent workpiece.

According to an embodiment of the present invention, a lens optical system and a laser processing apparatus including the same are provided.

In one aspect of the invention,

A body part including a first surface on which light is incident and a second flat surface disposed on an opposite side of the first surface;

A circular lens unit provided to be positioned at the center of the second surface; And

And at least one annular lens unit disposed on the second surface to surround the circular lens unit.

The circular lens unit and the at least one annular lens unit have different radii of curvature to provide a lens optical system for forming a plurality of condensing points spaced apart along the traveling direction of the light.

Each of the at least one annular lens unit may have a shape in which the thickness becomes thinner as it moves away from the circular lens unit.

The circular lens portion may have a smaller radius of curvature than each of the at least one annular lens portion. In this case, the at least one annular lens unit may include a plurality of annular lens units having a larger radius of curvature as the distance from the circular lens unit increases.

Each of the circular lens unit and the at least one annular lens unit may have the same light incident area. The circular lens unit may have a light incident area smaller than each of the at least one annular lens unit. In this case, the at least one annular lens unit may include a plurality of annular lens units having a larger light incident area as the distance from the circular lens unit is increased.

A laser beam having an intensity of a Gaussian shape, a dog ear type shape, or a flat shape may be incident on the first surface of the body part.

In another aspect,

A laser light source for emitting laser light; And

And a focusing unit configured to focus the laser light emitted from the laser light source and irradiate the substrate.

The focusing unit,

A body portion including a first surface on which the laser light is incident and a second flat surface positioned opposite to the first surface;

The circular lens unit and the at least one annular lens unit have different radii of curvature to provide a laser processing apparatus for forming a plurality of condensing points spaced apart along the thickness direction of the substrate.

The substrate may include a material having transparency to the laser light. The laser processing apparatus may further include a scan unit that scans the laser light irradiated onto the substrate along a processing direction.

The circular lens portion may have a smaller radius of curvature than each of the at least one annular lens portion. In this case, the at least one annular lens unit may include a plurality of annular lens units having a larger radius of curvature as the distance from the circular lens unit is increased.

The laser light source may emit a laser beam having a Gaussian type intensity. In this case, the circular lens unit may have a light incident area smaller than that of each of the at least one annular lens unit. The at least one annular lens unit may include a plurality of annular lens units having a larger light incident area as the at least one annular lens unit moves away from the circular lens unit.

The apparatus may further include a beam forming unit provided between the laser light source and the focusing unit to modify the laser beam emitted from the laser light source to have a dog-ear type or a flat shape. In this case, each of the circular lens unit and the at least one annular lens unit may have the same light incident area.

In another aspect,

In a method of processing a substrate by focusing the laser light using a lens optical system,

The lens optical system may include a body part including a first surface on which the laser light is incident and a flat second surface opposite to the first surface, a circular lens part disposed to be positioned at the center of the second surface; And at least one annular lens portion provided to surround the circular lens portion on the second surface.

The circular lens unit and the at least one annular lens unit have different radii of curvature, so that the laser light is multi-focused by the lens optical system to form a plurality of focusing points spaced apart from each other along the thickness direction of the substrate. A method is provided.

The substrate may include a material having transparency to the laser light, such that at least one of the plurality of light collecting points may be formed inside the substrate.

According to the exemplary embodiment of the present invention, since the lens optical system includes a plurality of lens units having different radii of curvature, a plurality of light collecting points may be simultaneously formed along the thickness direction of the substrate, thereby reducing processing time of the transparent substrate. That is, in the past, the processing steps have to be repeatedly performed as the processing depth of the substrate is changed, but using the lens optical system according to the present embodiment can greatly reduce the processing time of the substrate since the substrate can be processed in one process. have.

In the conventional transparent substrate processing, there were limitations depending on the processing direction such as processing from the top to the bottom or from the bottom to the top along the thickness direction of the substrate. However, when the lens optical system according to the present embodiment is used, the substrate is processed. Directional constraints can disappear. By making the plurality of light collecting points formed along the thickness direction of the substrate have an effective focal length suitable for processing conditions, instability depending on the performance of other optical systems can be eliminated, and energy can be used efficiently.

The aberration and the focal length can be variously adjusted by adjusting the radius of curvature or the distance between the lens portions of the plurality of lens portions constituting the lens optical system. In addition, by providing a plurality of lens portions having different radii of curvature on the plane of the body portion, the thickness thereof can be made thinner and lighter than conventional multifocal optical systems. Since the lens optical system may be manufactured using a mold, mass production is easier than that of the conventional production using a polishing method. Transparent substrates containing heterogeneous materials, for example, wafer substrates composed of multiple layers such as insulating layers and silicon wafers, can be processed in a single process, thereby shortening the processing time.

1 is a cross-sectional view illustrating a lens optical system according to an exemplary embodiment of the present invention.

FIG. 2 illustrates a bottom surface of the lens optical system illustrated in FIG. 1.

FIG. 3 illustrates a state in which laser light is incident on the lens optical system illustrated in FIG. 1 to form a plurality of light collecting points on a substrate.

4A to 4D illustrate a method of manufacturing the lens optical system shown in FIG. 1.

5 schematically shows a laser processing apparatus according to another exemplary embodiment of the present invention.

FIG. 6 illustrates a state in which the laser light is irradiated onto the substrate through the focusing unit in the laser processing apparatus shown in FIG. 5.

7 schematically illustrates a laser processing apparatus according to another exemplary embodiment of the present invention.

FIG. 8 illustrates a state in which the laser light is irradiated onto the substrate through the focusing unit in the laser processing apparatus shown in FIG. 7.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; The examples illustrated below are not intended to limit the scope of the invention, but are provided to explain the invention to those skilled in the art. Like reference numerals in the drawings refer to like elements, and the size or thickness of each element may be exaggerated for clarity. Also, when it is described that a layer of material is present in a substrate, the material layer may be in direct contact with the substrate, and another third layer may be present therebetween.

1 is a cross-sectional view illustrating a lens optical system according to an exemplary embodiment of the present invention. 2 illustrates a bottom surface of the lens optical system illustrated in FIG. 1.

1 and 2, the lens optical system 10 includes a body 11 and a plurality of lens units S1, S2, S3, and S4 having different radii of curvature provided in the body 11. Include. The body portion 11 may include a first surface 11a through which light is incident and a second surface 11b positioned opposite to the first surface 11a. The body portion 11 may include a transparent material that transmits incident light.

The first surface 11a (the upper surface in FIG. 1) of the body portion 11 may have a convex shape as a surface on which light is incident. However, the present invention is not limited thereto, and the first surface 11a may have a flat or concave shape. In addition, the second surface 11b (the lower surface in FIG. 1) of the body portion 11 may have a flat shape as a surface through which light incident from the first surface 11 passes.

A plurality of lens portions S1, S2, S3, and S4 having different radii of curvature are provided on the flat second surface 11b of the body portion 11. The plurality of lens units S1, S2, S3, and S4 may include the second, third, and fourth lens units S2 that sequentially surround the first lens unit S1 and the first lens unit S1. , S3, S4).

The first lens unit S1 may be a circular lens unit provided at the center portion of the second surface 11b. The first lens unit S1 may have a first radius of curvature. Each of the second, third, and fourth lens units S2, S3, and S4 may be an annular lens unit that sequentially surrounds the first lens unit S1. Specifically, the second lens unit S2 is provided to surround the first lens unit S1, and the third lens unit S3 is provided to surround the second lens unit S2. The fourth lens unit S4 is provided to surround the third lens unit S3. The second, third, and fourth lens units S2, S3, and S4 may have second, third, and fourth curvature radii, respectively. Here, the second, third, and fourth lens units S2, S3, and S4 may have shapes that become thinner as they move away from the first lens unit S1, as shown in FIG. 1. .

In the present embodiment, the first, second, third and fourth lens units S1, S2, S3, and S4 may have different radii of curvature. For example, the first, second, third, and fourth lens units S1, S2, S3, and S4 may have larger curvature radii as they move away from the first lens unit. Accordingly, the first, second, third, and fourth lens units S1, S2, S3, and S4 may have first, second, third, and fourth curvature radii of which values are sequentially increased. However, the present invention is not limited thereto, and the first, second, third, and fourth lens units S1, S2, S3, and S4 may have different radii of curvature.

As such, the lens optical system 10 includes first, second, third, and fourth lens units S1, S2, S3, and S4 having different radii of curvature so that each of the lens optical systems 10 may be arranged along the traveling direction of light as described below. A plurality of light collecting points having different focal lengths may be formed.

FIG. 3 illustrates a state in which laser light is incident on the lens optical system illustrated in FIG. 1 to form a plurality of light collecting points on a substrate. Here, the first, second, third and fourth lens units S1, S2, S3, and S4 have first, second, third, and fourth curvature radii that increase in order. As the substrate W, a transparent substrate capable of transmitting laser light was used.

Referring to FIG. 3, the laser light L is incident through the first surface 11a of the body portion 11 to pass through the body portion 11, and then the first, second, third and fourth lenses. Focused by the portions S1, S2, S3, and S4, the substrate W is irradiated. Here, since the first, second, third and fourth lens units S1, S2, S3, and S4 have different radii of curvature, the advancing direction of the laser light L, that is, the thickness direction of the substrate W A plurality of condensing points (P1, P2, P3, P4) having different focal lengths are thus formed.

Specifically, since the first lens unit S1 has the smallest first radius of curvature, the first lens unit S1 may form the shortest focal length. Accordingly, the first laser light L1 incident on the first lens unit S1 of the laser light L is focused by the first lens unit S1, for example, on the upper surface of the substrate W. Condensing point P1 can be formed. In addition, since the second lens unit S2 has a second radius of curvature greater than the first radius of curvature, the second lens unit S2 may have a larger focal length than the first lens unit S1. Accordingly, the second laser light L2 incident on the second lens unit S2 of the laser light L is focused by the second lens unit S2, and the second light collecting point ( P2) can be formed. Here, the second light collecting point P2 may be formed at a predetermined depth d1 from the upper surface of the substrate W.

Since the third lens unit S3 has a third radius of curvature greater than the second radius of curvature, the third lens unit S3 may form a larger focal length than the second lens unit S2. Accordingly, the third laser light L3 incident on the third lens unit S3 of the laser light L is focused by the third lens unit S3, and the third condensing point (3) is formed inside the substrate (W). P3) can be formed. Here, the third light collecting point P3 may be formed at a predetermined depth d2 (> d1) from the upper surface of the substrate W. In addition, since the fourth lens unit S4 has a fourth radius of curvature greater than the third radius of curvature, the fourth lens unit S4 may form a larger focal length than the third lens unit S3. Accordingly, the fourth laser light L4 incident from the laser light L into the fourth lens part S4 is focused by the fourth lens part S4 and the fourth condensing point is formed inside the substrate W. As shown in FIG. (P4) can be formed. Here, the fourth light collecting point P4 may be formed at a predetermined depth d3 (> d2) from the upper surface of the substrate W.

As described above, the lens optical system 10 includes the first, second, third, and fourth lens units S1, S2, S3, and S4 having different radii of curvature, thereby advancing the direction of the laser light L, That is, the first, second, third, and fourth light collecting points P1, P2, P3, and P4 spaced apart at predetermined intervals along the thickness direction of the substrate W may be simultaneously formed. As described above, when the plurality of light collecting points P1, P2, P3, and P4 are simultaneously formed on the substrate W along the thickness direction, the laser processing time for the substrate W can be shortened as described later.

The laser light L incident on the first surface 11a of the body portion 11 may be a dog-ear type or flat type light having almost uniform intensity regardless of the position on the first surface 11a. have. Here, the dog-ear type beam means a beam whose intensity is flat in the center and pointed at both ends. In this case, the first, second, third, and fourth light collecting points P1, P2, P3, and P4 formed along the thickness direction of the substrate W may have the same energy density. The third and fourth lens units S1, S2, S3, and S4 may have the same light incident area. On the other hand, the laser light L incident on the first surface 11a of the body portion 11 has a Gaussian shape of light whose intensity gradually decreases from the center portion of the first surface 11a to the edge portion. May be In this case, the first, second, third, and fourth light collecting points P1, P2, P3, and P4 formed along the thickness direction of the substrate W may have the same energy density. The third and fourth lens units S1, S2, S3, and S4 may have different light incident areas. In detail, the first, second, third, and fourth lens units S1, S2, S3, and S4 may have light incident areas having a larger value.

In the above-described lens optical system 10, three second, third, and fourth lens units S2, S3, and S4 are provided to surround the first lens unit S1, which is a circular lens unit. However, the present invention is not limited thereto, and the number of the annular lens units surrounding the first lens unit S1 may be modified depending on the processing conditions of the substrate W or the design conditions of the lens optical system 10.

When the substrate W is processed using the lens optical system 10 described above, the following effects can be obtained.

The lens optical system 10 includes a plurality of lens units S1, S2, S3, and S4 having different radii of curvature so that the plurality of light collecting points P1, P2, P3, and P4 along the thickness direction of the substrate W are included. Can be formed at the same time, the processing time of the substrate (W) can be shortened. That is, in the related art, the processing depths of the substrate W need to be repeatedly performed, but when the lens optical system 10 according to the present embodiment is used, the substrate W may be processed in one process. Machining time can be greatly shortened.

In the conventional transparent substrate processing, there were limitations depending on the processing direction, such as processing from the top to the bottom or from the bottom to the top along the thickness direction of the substrate, but when using the lens optical system 10 according to the present embodiment Constraints according to the processing direction of the substrate W may disappear. The plurality of condensing points P1, P2, P3, and P4 formed along the thickness direction of the substrate W have an effective focal length suitable for processing conditions, thereby eliminating instability depending on the performance of other optical systems and making energy efficient. Can be used as

By varying the radius of curvature of the plurality of lens units S1, S2, S3, S4 constituting the lens optical system 10 or the interval between the lens units S1, S2, S3, S4, the aberration and the focal length can be varied. I can regulate it. In addition, by providing a plurality of lens units (S1, S2, S3, S4) having different radii of curvature in the plane of the body portion 11, the thickness thereof can be made thinner and lighter than conventional multi-focused optical systems.

Since the lens optical system 10 may be manufactured using a mold, mass production of the lens optical system 10 is easier than that of the conventional production method using a polishing method. Transparent substrates containing heterogeneous materials, for example, wafer substrates composed of multiple layers such as insulating layers and silicon wafers, can be processed in a single process, thereby shortening the processing time.

Referring to Figure 4a, to prepare a body portion (11). Here, the first surface 11a of the body portion 11 to which light is incident may have a convex shape. However, the present invention is not limited thereto, and the first surface 11a of the body portion 11 may have a flat or concave shape. In addition, the second surface 11b of the body portion 11 may have a flat shape. Next, the first lens portion S1 having the first radius of curvature is coupled to the second flat surface 11b of the body portion 11. Here, the first lens unit S1 may be attached to the center portion of the second surface 11b as a circular lens unit. The first lens unit S1 may be manufactured by processing the first lens member 21 having the first radius of curvature into a circular lens having a predetermined size.

Referring to FIG. 4B, the second lens unit S2 is coupled to the flat second surface 11b of the body 11 to surround the first lens unit S1. Here, the second lens unit S2 may have a second radius of curvature different from the first radius of curvature. The second lens part S2 may be attached to the second surface 11b as an annular lens part and surround the first lens part S1. The second lens unit S2 may be manufactured by processing the second lens member 22 having the second radius of curvature into an annular lens having a larger size than the first lens unit S !.

Referring to FIG. 4C, the third lens part S3 is coupled to the second flat part 11b of the body part 11 so as to surround the second lens part S2. Here, the third lens unit S3 may have a third radius of curvature different from the first and second radius of curvature. The third lens unit S3 is an annular lens unit and may be attached to the second surface 11b in a form surrounding the second lens unit S2. The third lens unit S3 may be manufactured by processing the third lens member 23 having the third radius of curvature into an annular lens having a larger size than the second lens unit S2.

Referring to FIG. 4D, when the fourth lens unit S4 is coupled to the second surface 11b of the body 11 to surround the third lens unit S3, the lens optical system 10 illustrated in FIG. Is completed. Here, the fourth lens unit S4 may have a fourth radius of curvature different from the first, second, and third radius of curvature. The fourth lens unit S4 may be attached to the second surface 11b as an annular lens unit having a shape surrounding the third lens unit S3. The fourth lens unit S4 may be manufactured by processing the fourth lens member 24 having the fourth radius of curvature into an annular lens having a size larger than that of the third lens unit S3.

5 schematically shows a laser processing apparatus according to another exemplary embodiment of the present invention. 6 illustrates a state in which the laser light is irradiated onto the substrate through the focusing unit in the laser processing apparatus shown in FIG. 5.

5 and 6, the laser processing apparatus 100 focuses the laser light source 110 that emits the laser light L and the laser light L emitted from the laser light source 110 to focus the substrate W. As shown in FIG. It includes a focusing unit 150 for irradiating). The substrate W, which is the object to be processed, may be mounted on the stage 50. As the substrate W, a transparent substrate that is transparent to the laser light L may be used.

The laser light source 110 emits laser light L to be processed on the substrate W. In this case, the laser light L emitted from the laser light source may have a Gaussian shape in which intensity decreases from the center portion to the edge portion. The laser light source 110 may emit laser light L in various wavelength ranges. For example, the laser light source may emit, but is not limited to, infrared (IR) laser light, ultraviolet (UV) laser light, or green laser light.

A scan unit 130 may be provided between the laser light source 110 and the focusing unit 150. The scan unit! 30 may serve to scan the laser light L while moving along the processing direction of the substrate W through a reflection mirror or the like. Meanwhile, a predetermined optical system 120 such as a beam expansion unit may be further provided between the laser light source 110 and the scan unit 130.

A beam shaping unit 140 may be provided between the scan unit 130 and the focusing unit 150. The beam shaping unit 140 emits the light by changing the shape of the incident laser light L. In the present embodiment, the beam shaping unit 140 has a Gaussian-type intensity emitted from the laser light source 110. It may serve to convert the laser light (L) having a type or flat type of intensity. Here, the laser light L having a dog ear type shape or a flat shape intensity may have a shape that is almost uniform in intensity regardless of the position. As such, the laser light L having the doge type or flat shape intensity emitted from the beam shaping unit 140 is incident on the focusing unit 150.

The focusing unit 150 may serve to focus the incident laser light L to form a plurality of focusing points P1, P2, P3, and P4 on the substrate W. Here, the light collecting points P1, P2, P3, and P4 may be formed to be spaced apart at regular intervals along the thickness direction of the substrate W. The focusing unit 150 has the same configuration as the lens optical system 10 shown in FIG. 1 described above. That is, the focusing unit 150 includes a body portion 151 and a plurality of lens portions S1, S2, S3, and S4 having different radii of curvature provided in the body portion 151.

The body portion 151 may include a first surface 151a through which light is incident and a second surface 151b positioned opposite to the first surface 151a. Here, the first surface 151a of the body portion 151 may have a convex shape as a surface on which the laser beam L having the intensity of the dog-ear type or the flat shape emitted from the beam forming unit 140 is incident. have. However, the present invention is not necessarily limited thereto, and the first surface 151a may have a flat or concave shape.

The second surface 151b of the body portion 151 may have a flat shape as a surface through which the laser light L incident from the first surface 151 passes. A plurality of lens portions S1, S2, S3, and S4 having different radii of curvature are provided on the second flat surface 151b of the body portion 151. The plurality of lens units S1, S2, S3, and S4 may include the second, third, and fourth lens units S2 that sequentially surround the first lens unit S1 and the first lens unit S1. , S3, S4). The first lens unit S1 may be a circular lens unit provided at the center portion of the second surface 11b. The first lens unit S1 may have a first radius of curvature. Each of the second, third, and fourth lens units S2, S3, and S4 may be an annular lens unit that sequentially surrounds the first lens unit S1. The second, third, and fourth lens units S2, S3, and S4 may have second, third, and fourth curvature radii, respectively. Here, the second, third and fourth lens units S2, S3, and S4 may have shapes that become thinner as they move away from the first lens unit S1, respectively.

The first, second, third and fourth lens units S1, S2, S3 and S4 may have different radii of curvature. For example, the first, second, third, and fourth lens units S1, S2, S3, and S4 may have larger curvature radii as they move away from the first lens unit. However, this is merely illustrative and the first, second, third and fourth lens units S1, S2, S3, and S4 may have other various radii of curvature.

As described above, the first, second, third and fourth lens units S1, S2, S3, and S4 constituting the focusing unit have different radii of curvature, so that the substrate W may be formed as shown in FIG. 6. A plurality of light collecting points P1, P2, P3, and P4 may be formed to be spaced apart from each other along the thickness direction. FIG. 6 shows a condensing point that may be formed when the first, second, third and fourth lens units S1, S2, S3, and S4 have larger radii of curvature as they move away from the first lens unit S1. (P1, P2, P3, P4) are shown.

Specifically, light incident on the first lens unit S1 of the laser light L is focused by the first lens unit S1 to, for example, place the first condensing point P1 on the upper surface of the substrate W. FIG. The light incident on the second lens unit S2 among the laser lights L may be focused by the second lens unit S2, and the second light collecting point may be formed at a predetermined depth d1 from the upper surface of the substrate W. P2) can be formed. Here, the second light collecting point P2 may be formed at a predetermined depth d1 from the upper surface of the substrate W. In addition, the light incident on the third lens unit S3 among the laser lights L is focused by the third lens unit S3, and the third condensing point is formed at a predetermined depth d2 (> d1) from the upper surface of the substrate W. P3 may be formed, and the light incident from the laser light L into the fourth lens part S4 is focused by the fourth lens part S4, and the predetermined depth d3 (from the upper surface of the substrate W) is obtained. The fourth light collecting point P4 may be formed at> d2. Accordingly, the first, second, third and fourth condensing points P1, P2, P3, and P4 spaced apart at predetermined intervals along the thickness direction of the substrate W may be simultaneously formed.

Meanwhile, in the present embodiment, the laser beam L having the intensity of the dog-ear type or the flat shape is incident on the focusing unit 150 by the beam shaping unit 140. This means that the laser light L having a uniform intensity is incident on the first surface 151a of the body portion 151. In this case, the first, second, third and fourth lens units S1, S2, S3, and S4 may have the same light incident areas. Accordingly, the first, second, third and fourth light collecting points P1, which are formed on the substrate W by the first, second, third and fourth lens units S1, S2, S3, and S4. Since the energy density in P2, P3, P4 becomes uniform, the process of the board | substrate W can be processed more easily and precisely. Meanwhile, the case in which the focusing unit 150 includes four lens units S1, S2, S3, and S4 has been exemplarily described. However, the present invention is not limited thereto, and the focusing unit 150 includes the lens units S1, S2, S3, and S4. The number can vary.

A plurality of condensing points P1, P2, along the thickness direction of the substrate W by the focusing unit 150 including a plurality of lens units S1, S2, S3, S4 having different radii of curvature as described above. Since P3 and P4 can be formed simultaneously, the processing time of the board | substrate W can be shortened.

In addition, by providing a plurality of lens units (S1, S2, S3, S4) having different radii of curvature in the plane of the body portion 151, the thickness thereof can be made thinner and lighter than that of a conventional multifocal optical system. In addition, a transparent substrate including a dissimilar material, for example, a wafer substrate composed of multiple layers such as an insulating layer and a silicon wafer can be processed in a single process, thereby shortening the processing time.

7 schematically illustrates a laser processing apparatus according to another exemplary embodiment of the present invention. 8 illustrates a state in which the laser light is irradiated onto the substrate through the focusing unit in the laser processing apparatus illustrated in FIG. 7.

7 and 8, the laser processing apparatus 200 focuses a laser light source 210 emitting laser light L and a laser light L emitted from the laser light source 210 and irradiates the substrate. It includes a focusing unit 250 to be.

The laser light source 210 may have a Gaussian shape in which intensity decreases from the center portion to the edge portion thereof. A scan unit 230 may be provided between the laser light source 210 and the focusing unit 250 between the laser light source and the focusing unit. Meanwhile, a predetermined optical system 220 such as a beam expansion unit may be further provided between the laser light source 210 and the scan unit 230.

The focusing unit 250 may focus the incident laser light L to form a plurality of focusing points P1, P2, P3, and P4 on the substrate W. As illustrated in FIG. These light collecting points P1, P2, P3, and P4 may be formed to be spaced apart at regular intervals along the thickness direction of the substrate W. FIG. As described above, the focusing unit includes a body part 251 and a plurality of lens parts S1, S2, S3, and S4 having different radii of curvature provided in the body part 251.

The body part 251 may include a first surface 251a through which light is incident and a second surface 251b positioned opposite to the first surface 251a. Here, the first surface 251a of the body portion 251 is a surface on which laser light having a Gaussian intensity is incident. The second surface 251 b of the body part 251 may have a flat shape as a surface through which the laser light L incident from the first surface 251 passes. A plurality of lens parts S1, S2, S3, and S4 having different radii of curvature are provided on the second flat surface 251 b of the body part 251. The plurality of lens units S1, S2, S3, and S4 may include the second, third, and fourth lens units S2 that sequentially surround the first lens unit S1 and the first lens unit S1. , S3, S4). Here, the second, third and fourth lens units S2, S3, and S4 may have shapes that become thinner as they move away from the first lens unit S1, respectively. Since the plurality of lens units S1, S2, S3, and S4 have been described above, a detailed description thereof will be omitted.

The first, second, third and fourth lens units S1, S2, S3 and S4 may have different radii of curvature. For example, the first, second, third, and fourth lens units S1, S2, S3, and S4 may have larger curvature radii as they move away from the first lens unit. As such, the first, second, third and fourth lens units S1, S2, S3, and S4 constituting the focusing unit have different radii of curvature, so that the thickness of the substrate on the substrate as shown in FIG. A plurality of light collecting points P1, P2, P3, and P4 may be formed to be spaced apart from each other along the direction. 8, the first, second, third, and fourth lens units S1, S2, S3, and S4 may be formed when the first, second, third, and fourth lens units have larger radius of curvature as they move away from the first lens unit. , Third and fourth condensing points P1, P2, P3, P4 are shown.

In the present embodiment, the laser light L having a Gaussian-type intensity whose intensity decreases from the center portion to the edge portion is incident on the focusing unit 250. Accordingly, light of the strongest intensity may be incident on the first lens unit S1, and light of the weakest intensity may be incident on the fourth lens unit S4. In this case, as the first, second, third, and fourth lens units S1, S2, S3, and S4 move away from the first lens unit S1, light incident areas may increase. In this way, the first, second, third, and fourth lens units S1, S2, S3, and S4 are provided to have a larger light incident area, thereby forming the first, second, and third lenses. The energy density at the third and fourth light collecting points P1, P2, P3, and P4 can be made uniform, and as a result, the processing of the substrate W can be made easier and more precise. Meanwhile, the case in which the focusing unit 250 includes four lens units S1, S2, S3, and S4 has been exemplarily described. However, the present invention is not limited thereto, and the focusing unit 250 includes the lens units S1, S2, S3, and S4. The number can vary.

Although embodiments of the present invention have been described above, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

Claims

A body part including a first surface on which light is incident and a second flat surface disposed on an opposite side of the first surface;

A circular lens unit provided to be positioned at the center of the second surface; And

And at least one annular lens unit disposed on the second surface to surround the circular lens unit.

And the circular lens unit and the at least one annular lens unit have a different radius of curvature to form a plurality of condensing points spaced apart along the traveling direction of the light.
The method of claim 1,

And each of the at least one annular lens portion has a shape in which the thickness becomes thinner as it moves away from the circular lens portion.
The method of claim 1,

And the circular lens unit has a radius of curvature smaller than each of the at least one annular lens unit.
The method of claim 3, wherein

The at least one annular lens unit includes a plurality of annular lens units having a larger radius of curvature as the distance from the circular lens unit.
The method of claim 1,

And each of the circular lens portion and the at least one annular lens portion has the same light incident area.
The method of claim 1,

And the circular lens unit has a light incident area smaller than each of the at least one annular lens unit.
The method of claim 6,

The at least one annular lens unit includes a plurality of annular lens units having a larger light incident area as the distance from the circular lens unit.
The method of claim 1,

And a laser beam having a Gaussian shape, a dog ear type shape, or a flat shape intensity on the first surface of the body portion.
A laser light source for emitting laser light; And

And a focusing unit configured to focus the laser light emitted from the laser light source and irradiate the substrate.

The focusing unit,

A body portion including a first surface on which the laser light is incident and a second flat surface positioned opposite to the first surface;

A circular lens unit provided to be positioned at the center of the second surface; And

And at least one annular lens unit disposed on the second surface to surround the circular lens unit.

And the circular lens portion and the at least one annular lens portion have different radii of curvature to form a plurality of condensing points spaced apart along the thickness direction of the substrate.
The method of claim 9,

And the substrate comprises a material having transparency to the laser light.
The method of claim 9,

And a scanning unit for scanning the laser light irradiated onto the substrate along a processing direction.
The method of claim 9,

And each of the at least one annular lens portion has a shape in which the thickness becomes thinner as it moves away from the circular lens portion.
The method of claim 9,

And said circular lens portion has a radius of curvature smaller than each of said at least one annular lens portion.
The method of claim 13,

And said at least one annular lens portion comprises a plurality of annular lens portions having a larger radius of curvature as they move away from the circular lens portion.
The method of claim 9,

The laser light source is a laser processing device for emitting a laser beam having a Gaussian type intensity.
The method of claim 15,

And the circular lens portion has a light incident area smaller than each of the at least one annular lens portion.
The method of claim 16,

And the at least one annular lens portion comprises a plurality of annular lens portions having a larger light incident area as the at least one annular lens portion moves away from the circular lens portion.
The method of claim 9,

And a beam forming unit provided between the laser light source and the focusing unit to deform the laser beam emitted from the laser light source to have a dog-ear type or a flat shape.
The method of claim 18,

And the circular lens portion and the at least one annular lens portion each have the same light incident area.
In a method of processing a substrate by focusing the laser light using a lens optical system,

The lens optical system may include a body part including a first surface on which the laser light is incident and a flat second surface opposite to the first surface, a circular lens part disposed to be positioned at the center of the second surface; And at least one annular lens portion provided to surround the circular lens portion on the second surface.

The circular lens unit and the at least one annular lens unit have different radii of curvature, so that the laser light is multi-focused by the lens optical system to form a plurality of focusing points spaced apart from each other along the thickness direction of the substrate. Way.
The method of claim 20,

And the substrate includes a material having transparency to the laser light, such that at least one of the plurality of light collecting points is formed inside the substrate.