WO2017073907A1

WO2017073907A1 - Laser processing method and laser processing device, which use multiple focuses

Info

Publication number: WO2017073907A1
Application number: PCT/KR2016/010232
Authority: WO
Inventors: 박정래; 이홍
Original assignee: (주)이오테크닉스
Priority date: 2015-10-27
Filing date: 2016-09-12
Publication date: 2017-05-04
Also published as: TW201714694A; KR20170048969A

Abstract

A laser processing method and a laser processing device, which use multiple focuses, are disclosed. The disclosed laser processing method processes, using a laser, an object to be processed, which is loaded on a stage, and comprises the steps of: splitting a laser beam into a plurality of laser beams; emitting the plurality of split laser beams at the object to be processed, so as to respectively form focusing points at different depths; and processing the object to be processed by relatively moving, with respect to the stage, the laser beams along a line scheduled to be processed, wherein a focusing point formed at a deeper position from the surface of the object to be processed, on which the laser beams are incident, is formed more toward the moving direction of the laser beams than a focusing point formed at a shallower position in the line scheduled to be processed.

Description

Laser processing method and laser processing device using multiple focus

TECHNICAL FIELD The present invention relates to a laser processing method and a laser processing apparatus, and more particularly, to a laser processing method and a laser processing apparatus for forming and cutting a plurality of condensing points inside a workpiece.

The laser processing apparatus irradiates a laser beam emitted from a laser oscillator to an object to be processed by using an optical system, and marking, exposure, etching, punching, scribing, and die of the object is processed by the laser beam. Laser processing such as dicing is performed.

In recent years, in order to prevent the surface of a workpiece from being damaged, a method of processing a workpiece by generating a crack by forming a light collecting point inside a transparent workpiece has been spotlighted. For example, when a laser beam of high output of a semiconductor wafer is focused to form a focusing point, a modified region is formed near the focused point, and cracks are generated from the modified region thus formed. Subsequently, when the laser beam is moved along the processing line of the semiconductor wafer, cracks are formed inside the object, and then the object may be cut by extending the crack to the surface of the semiconductor wafer by natural or external force.

However, in the conventional laser processing method and laser processing apparatus, the condensing points are arranged in the horizontal direction, and the condensing points are formed at the same depth, so that the number of times required for cutting the object to be processed is high, and thus it is impossible to apply it at high speed. have.

The present invention provides a laser processing method and a laser processing apparatus for forming and processing a plurality of condensing points inside a workpiece.

According to an aspect of the present invention, there is provided a laser processing method comprising: splitting a laser beam into a plurality of laser beams in a laser processing method for processing a processing object loaded on a stage using a laser; Transmitting the plurality of divided laser beams through the object to form condensing spots at different depths; And moving the laser beam relative to the stage along a machining line to process the object to be processed, wherein the focusing point formed at a position deeper from a plane on which the laser beam of the object is incident It is formed in the moving direction of the laser beam at the line to be processed, rather than a light collecting point formed at a shallower position.

According to an embodiment of the present invention, since a plurality of condensing points are formed in the depth of the object to be processed in the depth direction of the object to be processed, it is not necessary to repeat the process several times in a process such as cutting, thereby reducing the time required. .

In addition, according to an embodiment of the present invention, since the condensing point formed at a position deeper from the plane where the laser beam is incident is formed on the moving direction of the laser beam than the condensing point formed at the shallower position, the laser beam when the object to be processed is processed. Interference can be prevented by this modified region.

1 schematically shows a laser processing apparatus according to an exemplary embodiment of the present invention.

2a to 2c illustrate a laser processing method according to an embodiment of the present invention.

3A to 3D illustrate a laser processing method according to another embodiment of the present invention.

4a to 4c illustrate a laser processing method according to another embodiment of the present invention.

5 illustrates an object to be processed according to an exemplary embodiment of the present invention.

In the dividing of the laser beam into a plurality of laser beams, the laser beam may be split by passing the laser beam through a plurality of lenses having different focal lengths.

The plurality of lenses may have a larger focal length than a lens positioned in a movement direction of the laser beam in a direction opposite to the movement direction of the laser beam.

In the dividing of the laser beam into a plurality of laser beams, the laser beam may be split by passing the laser beam through a diffractive optical element lens.

The processing of the object by moving the laser beam relative to the stage along the machining schedule line may include moving the stage or scanning the laser beam to process the object.

The object to be processed may be a transparent medium.

In a laser processing method according to an embodiment of the present invention, in a laser processing method for processing a processing object loaded on a stage by using a laser, the laser beam is passed through a spherical lens having a plurality of curved surfaces, and the plurality of focal lengths are different from each other. Dividing into two laser beams; Transmitting the plurality of divided laser beams through the object to form condensing spots at different depths; And processing the object by moving the laser beam relative to the stage along a machining schedule line.

The plurality of curved surfaces of the spherical lens may have different focal lengths.

A laser processing apparatus according to an embodiment of the present invention, the laser processing apparatus for processing the object to be loaded on the stage using a laser, the laser light source for emitting a laser beam; An optical system for dividing the laser beam into a plurality of laser beams to form condensing spots at different depths of the object to be processed, the light system being formed at a position deeper from a plane on which the laser beam of the object is incident; A point is formed on the side of the laser beam in the direction of movement of the line to be processed than a light collecting point formed at a shallower position.

The optical system may include a plurality of lenses having different focal lengths.

The optical system may include a diffractive optical element lens.

The stage may move relative to the laser beam to process the object.

The laser beam may be moved relative to the stage along the line to be processed.

A laser processing apparatus according to an embodiment of the present invention, the laser processing apparatus for processing the object to be loaded on the stage using a laser, the laser light source for emitting a laser beam; And a spherical lens having a plurality of curved surfaces for dividing the laser beam into a plurality of laser beams to form condensing points at different depths of the object. The spherical lenses include a plurality of curved surfaces having different focal lengths. It can be formed as.

The stage may move relative to the laser beam to process the object.

The apparatus may further include a scanner configured to move the laser beam relative to the stage along the processing line.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. . In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

Referring to FIG. 1, the laser processing apparatus according to the present embodiment includes a laser light source 110, a beam delivery system 120, a scanner 130, and a processing object 150 that emit a laser beam L. Stage 160.

The laser light source 110 refers to a means for emitting a laser, and the laser light source 110 may be classified into various types of gas, liquid, solid laser light source, etc. according to the type of material generating the laser.

The laser beam L emitted from the laser light source 110 is incident to the beam delivery system 120. The beam delivery system 120 transmits the laser beam L emitted from the laser light source 110 along a predetermined path, and may include, for example, a plurality of mirrors or an optical cable. .

The laser beam L that has passed through the beam delivery system 120 is incident to the scanner 130. The scanner 130 scans the laser beam L on the object to be processed 150, thereby serving to process the object to be processed 150. The scanner 130 may be positioned in the area to be processed the laser beam (L), it can control the linear motion of the laser beam (L).

The optical system 140 serves to adjust the focus of the laser beam L so that the laser beam L passing through the scanner 130 can form a condensing point inside the object 150. Specific embodiments, roles, and operating principles of the optical system 140 will be described later.

The object to be processed 150 may be formed of a transparent medium through which the laser beam L may pass.

The processing object 150 is seated and fixed to the stage 160. When the laser beam L passing through the optical system 140 is irradiated onto the object 150, the object 150 may be processed by the movement of the stage 160 on which the object 150 is seated. That is, by continuously irradiating the laser beam (L) on the object to be processed 150, the stage 160 to move to the desired shape can be processed to the object to be processed 150.

In addition, even when the stage 160 is fixed and the laser beam L is scanned in a desired shape using the scanner 130, the object 150 may be processed into a desired shape. That is, the path of the laser beam L may be changed by the movement of the mirror included in the scanner 130 to process the object 150 by moving relative to the object 150 on the stage 160. .

Hereinafter, a process of cutting the object to be processed 150 using the laser processing apparatus shown in FIG. 1 will be described with reference to FIGS. 2A to 5.

FIG. 2A illustrates a state in which a laser beam emitted from a laser processing apparatus is divided into a plurality of laser beams L1 and L2 to form first and second condensing points P1 and P2 inside the object 250. The first and second condensing points (P1, P2) is shown to move.

Referring to FIG. 2A, first, an object to be processed 250 is prepared. The object to be processed 250 may be formed of a transparent medium through which the laser beam L may pass.

The first and

second lenses

10 and 20 may be used as the optical system 140 of the laser processing apparatus shown in FIG. 1. In FIG. 1, the laser beam L emitted from the scanner 130 may be divided into the first and second laser beams L1 and L2 after passing through the first and

second lenses

10 and 20. The first lens and the

second lens

10 and 20 may have different focal lengths, and the focal length of the second lens 20 positioned in the moving direction of the laser beam L may correspond to the moving direction of the laser beam L2. The focal length may be greater than that of the first lens 10 positioned in the opposite direction.

In order that the first lens 10 and the second lens 20 have different focal lengths, the curvature of the first lens and the curvature of the second lens 20 may be different from each other. Alternatively, even though the first lens 10 and the second lens 20 have the same curvature, the refractive index of the first lens 10 and the second lens 20 may be different from each other. Alternatively, both the curvature and the refractive index of the first lens 10 and the second lens 20 may be different.

The first and second laser beams L1 and L2 penetrate the object 250 to form first and second light collecting points P1 and P2, respectively. Since the focal length of the second lens 20 has a larger value than the focal length of the first lens 10, the second condensing point P2 is formed by the first object of the workpiece 250 rather than the first condensing point P1. The first and second laser beams L1 and L2 may be formed deeper from the incident surface.

In addition, the second lens 20 having a larger focal length than the first lens 10 may be located in the moving direction of the laser beams L1 and L2 than the first lens 10 in the processing line S. FIG. have. Accordingly, the second condensing point P2 may be formed closer to the moving direction of the laser beams L1 and L2 than the first condensing point P1 in the processing line S. FIG.

As such, as the first and second condensing points P1 and P2 are formed inside the object 250, a modified region may be formed around the first and second condensing points P1 and P2. Cracks may form from the modified regions. Here, since the second condensing point P2 is formed on the movement direction side of the laser beams L1 and L2 in the processing line S than the first condensing point P1, the second condensing point P2 is the first condensing point. It can be formed without being disturbed by the modified region formed by the point P1.

FIG. 2B is a cross-sectional view taken along line II ′ of FIG. 2A.

Referring to FIG. 2B, as shown in FIG. 2A, the first and second light collecting points P1 and P2 are formed at different depths inside the object 250, respectively. P1 and P2 are moved relatively along the machining schedule line S. FIG. Accordingly, the first and second light collecting points P1 and P2 move in a predetermined direction (that is, in a direction opposite to the moving direction of the object to be processed). Movement of the first and second light collecting points P1 and P2 may be controlled by driving the scanner 130 of FIG. 1. Meanwhile, the movement of the first and second light collecting points P1 and P2 may also be controlled by the movement of the stage (160 of FIG. 1) on which the object 250 is mounted.

In this process, as the first and second converging points P1 and P2 are moved, crack

rows

211 and 212 are formed along the processing schedule line S in the inside of the object 250 and such cracks are formed. Cracks may extend from the

rows

211 and 212 to the top and bottom surfaces of the workpiece 250. As such, when the movement of the first and second light collecting points P1 and P2 within the object 250 ends, crack

rows

211 and 212 may be formed inside the object 250 as illustrated in FIG. 2C. Formation is complete.

In the above embodiment, the laser processing method and the laser processing apparatus have been described with two

lenses

10 and 20 having different focal lengths and two condensing points P1 and P2 having different forming depths, but are not limited thereto. The object may be processed by forming at least two lenses and at least two light collecting points.

According to the above embodiment, the plurality of condensing points (P1, P2) are formed at different depths inside the object to be processed to process the object 250, the process is not necessary to repeat the process several times Therefore, the time required can be shortened. Further, the light collecting point P2 formed at a position deeper from the plane where the laser beams L1 and L2 are incident is at the line S to be processed than the light collecting point P1 formed at a shallower position. Since it is formed on the side of the moving direction, the second condensing point P2 may be formed without being disturbed by the modified region formed from the first condensing point P1 when the object 250 is processed.

3A illustrates that the laser beam emitted from the laser processing apparatus is divided into a plurality of laser beams L1 ′, L2 ′, and L3 ′ so that the first, second and third condensing points P1 ′, The first, second and third light collecting points P1 ', P2', and P3 'are moved in a state where P2' and P3 'are formed.

Referring to FIG. 3A, the diffractive optical element 170 and the focusing lens 175 may be used as the optical system 140 of the laser processing apparatus shown in FIG. 1. In FIG. 1, the laser beam L emitted from the scanner 130 may be divided into first, second and third laser beams L1 ′, L2 ′, L3 ′ after passing through the diffractive optical element 170. have.

Looking at the structure of the diffractive optical element 170 in more detail as follows. Unlike refractive optical elements, such as commonly used convex lenses, diffractive optical elements perform the function of the lens through a plurality of diffraction gratings formed on the surface. 3B illustrates the structure of this diffractive optical element 170. As shown in FIG. 3B, the diffractive optical element 170 is formed by dividing the surface 172 of a general convex lens to a constant height and transferring the lens surface shape of each divided section onto the substrate 171 as it is. In general, since the portion of the light bent in the convex lens is the surface of the lens, it is possible to perform the function of the general lens as it is, as shown in FIG.

Referring again to FIG. 3A, the first, second and third laser beams L1 ′, L2 ′, L3 ′ passing through the diffractive optical element 170 pass through the focusing lens 175, and then the workpiece ( 350, first, second, and third light collecting points P1 ′, P2 ′, and P3 ′ are respectively formed therein. The first, second, and third light collecting points P1 ', P2', and P3 'may be formed at different depths on the object 350. The second condensing point P2 'is formed at a position deeper than the first condensing point P1' from the upper surface of the object to be processed 350, and the third condensing point P3 'is formed from the upper surface of the object to be processed 350 The position and shape of the diffractive optical element 170 may be adjusted to be formed at a position deeper than the second condensing point P2 ′.

Further, the second condensing point P2 'is located closer to the moving direction of the laser beam than the first condensing point P1' in the processing schedule line S, and the third condensing point P3 'is the processing schedule line S. ), The position and shape of the diffractive optical element 170 may be adjusted to be located closer to the moving direction of the laser beam than the second condensing point P2 ′.

As such, the first, second, and third condensing points P1 ′, P2 ′, and P3 ′ are formed inside the object 350, so that the first, second, and third condensing points P1 ′, P2 are formed. ', P3') may be formed around the modified region, and cracks may be formed from the modified region. Here, since the second condensing point P2 'is formed in the moving direction of the laser beam more than the first condensing point P1' in the processing line S, the second condensing point P2 'is the first condensing point ( It can be formed without being disturbed by the modified region formed by P1 '). In addition, since the third condensing point P3 'is formed on the moving direction of the laser beam more than the second condensing point P2' in the processing schedule line S, the third condensing point P3 'is the second condensing point. It can be formed without being disturbed by the modified region formed by (P2 ').

3C is a cross-sectional view taken along line II-II ′ of FIG. 3A.

Referring to FIG. 3C, as shown in FIG. 3A, the first, second, and third light collecting points P1 ′, P2 ′, and P3 ′ are formed at different depths inside the object 350, respectively. The first, second, and third light collecting points P1 ', P2', and P3 'are relatively moved along the machining schedule line S. FIG. Accordingly, the first, second and third light collecting points P1 ', P2', and P3 'move in a predetermined direction (that is, in a direction opposite to the moving direction of the object to be processed). Movement of the first, second, and third light collecting points P1 ', P2', and P3 'may be controlled by driving the scanner 130 of FIG. On the other hand, the movement of the first, second and third light collecting point (P1 ', P2', P3 ') can also be controlled by the movement of the stage (160 of FIG. 1) on which the processing object 350 is seated.

In this process, as the first, second and third light collecting points P1 ′, P2 ′, and P3 ′ move, crack

rows

311, 312, and 313 are to be processed inside the object 350. It is formed along the (S), the cracks may extend from the crack row (311, 312, 313) to the upper and lower surfaces of the object to be processed (350). As such, when the movement of the first, second, and third light collecting points P1 ′, P2 ′, and P3 ′ ends in the inside of the workpiece 350, the interior of the workpiece 350 is illustrated in FIG. 3D. The

crack rows

311, 312, and 313 are formed.

In the above embodiment, the laser beam is divided into three using the diffractive optical element 170 and the focusing lens 175, and three condensing points P1 ′ and P2 ′ P3 ′ are formed in the object 350. The laser processing method and the laser processing apparatus for processing the object 350 have been described. However, the present invention is not limited thereto, and the object may be processed by dividing the laser beam into three or more laser beams through the diffractive optical element, and forming three or more condensing points within the object.

According to the above embodiment, the processing object 350 is formed by forming a plurality of light collecting points P1 'and P2' P3 'at different depths in the processing object 350, and the processing is repeated several times in the processing process. Since this is not necessary, the time required can be shortened. Further, the light collecting point formed at a position deeper from the plane where the laser beams L1 ', L2', and L3 'are incident is formed on the moving direction side of the laser beam at the line to be processed S than the light collecting point formed at the shallower position. When the processing object 350 is processed, the light collecting point formed at a deeper position may be formed without being disturbed by the modified region formed from the light collecting point formed at a shallower position.

4A to 4B illustrate a laser processing method according to another embodiment of the present invention.

4A illustrates that the laser beam emitted from the laser processing apparatus is divided into a plurality of laser beams L1 ″, L2 ″, and L3 ″ so that the first, second, and third condensing points P1 ″, inside the object 450 are processed. The first, second, and third condensing points P1 ', P2', and P3 'are moved in a state where P2' and P3 'are formed.

Referring to FIG. 4A, the spherical lens 180 may be used as the optical system 140 of the laser processing apparatus shown in FIG. 1. In FIG. 1, the laser beam L emitted from the scanner 130 may be divided into first, second and third laser beams L1 ″, L2 ″, and L3 ″ after passing through the spherical lens 180.

The spherical lens 180 may have a plurality of

curved surfaces

181, 182, and 183, and the plurality of

curved surfaces

181, 182, and 183 may have different focal lengths, respectively. For example, the first curved surface 181 may have a larger focal length than the second curved surface 182, and the second curved surface 182 may have a larger focal length than the third curved surface 183. Accordingly, the first converging point P1 ″ formed by the first laser beam L1 ″ divided by the first curved surface 181 is divided into the second laser beam L2 ″ divided by the second curved surface 182. ) May be formed at a position deeper from an upper surface of the object 450 than the second condensing point P2 ″ formed. In addition, the second converging point P2 ″ formed by the second laser beam L2 ″ divided by the second curved surface 182 is the third laser beam L3 ″ divided by the third curved surface 183. The second light collecting point P3 ″ may be formed at a position deeper from the upper surface of the object 450 to be formed.

The spherical lenses 180 may have different curvatures so that the

curved surfaces

181, 182, and 183 have different focal lengths, respectively. For example, the first curved surface 181 may have a curvature greater than the second curved surface 182 and the third curved surface 183, and the second curved surface 182 may have a larger curvature than the third curved surface 183. Can be.

As such, the first, second and third condensing points P1 ″, P2 ″, and P3 ″ are formed inside the object 450, and thus, the first, second and third condensing points P1 ″, P2. ”, P3”) may be formed with a modified region, and cracks may be formed from the modified region.

4B is a cross-sectional view taken along line III-III ′ of FIG. 4A.

Referring to FIG. 4B, as shown in FIG. 4A, the first, second, and third light collecting points P1 ″, P2 ″, and P3 ″ are formed at different depths inside the object 450, respectively. The first, second and third light collecting points P1 ″, P2 ″, and P3 ″ are relatively moved along the machining schedule line S. FIG. Accordingly, the first, second and third light collecting points P1 ″, P2 ″, P3 ″ move in a predetermined direction (that is, in a direction opposite to the moving direction of the object to be processed). Movement of the first, second, and third light collecting points P1 ″, P2 ″, and P3 ′ may be controlled by driving the scanner 130 of FIG. 1. Meanwhile, the movement of the first, second and third light collecting points P1 ″, P2 ″, and P3 ″ may also be controlled by the movement of the stage (160 of FIG. 1) on which the object 450 is mounted.

In this process, as the first, second and third light collecting points P1 ″, P2 ″, and P3 ″ move, crack

rows

411, 412, 413 are to be processed inside the object 450. Formed along (S), cracks may extend from the

crack rows

411, 412, 413 to the upper and lower surfaces of the object 450. As such, when the movement of the first, second, and third light collecting points P1 ″, P2 ″, and P3 ″ ends in the inside of the object 350, the interior of the object 450 as illustrated in FIG. 4C. The

crack rows

411, 412, 413 are completed.

In the above embodiment, the laser beam is divided into three using spherical lenses 180 having a plurality of

curved surfaces

181, 182, and 183, and three condensing points P1 ″ and P2 ″ P3 inside the object 450. '') To describe the laser processing method and laser processing apparatus for processing the object to be processed 450. However, the present invention is not limited thereto, and the object may be processed by dividing the laser beam into three or more laser beams through spherical lenses having three or more curved surfaces, and forming three or more condensing points within the object.

According to the above embodiment, a plurality of light collecting points P1 ″, P2 ″ P3 ″ are formed at different depths in the object 450 to process the object 450, and the process is repeated several times in the process. Since this is not necessary, the time required can be shortened.

5 illustrates an object 150 ', 150 "processed according to an exemplary embodiment of the present invention.

Referring to FIG. 5, crack

lines

211, 212, 311, 312, 313, 411, 412, and 413 are arranged along the line S to be processed inside the

workpieces

250, 350, and 450 as shown in FIG. 5. ) Is applied to the workpiece (250, 350, 450) naturally or externally to form a plurality of workpieces (150 ', 150) by breaking (breaking) ”).

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims

In the laser processing method for processing the object to be loaded on the stage using a laser,

Dividing a laser beam into a plurality of laser beams;

Transmitting the plurality of divided laser beams through the object to form condensing spots at different depths; And

And moving the laser beam relative to the stage along a line to be processed to process the workpiece.

And a condensing point formed at a position deeper from a plane on which the laser beam of the object is incident is formed on the moving direction of the laser beam at the line to be processed than a condensing point formed at a shallower position.
The method of claim 1,

The dividing of the laser beam into a plurality of laser beams may include splitting the laser beam by passing the laser beam through a plurality of lenses having different focal lengths.
The method of claim 2,

And wherein the plurality of lenses have a focal length greater than that of a lens positioned in a movement direction of the laser beam in a direction opposite to a movement direction of the laser beam.
The method of claim 1,

The dividing of the laser beam into a plurality of laser beams may include splitting the laser beam by passing the laser beam through a diffractive optical element lens.
The method of claim 1,

And processing the object by moving the laser beam relative to the stage along the machining line, processing the object by moving the stage or scanning the laser beam.
The method of claim 1,

The processing object is a laser processing method is a transparent medium.
In the laser processing method for processing the object to be loaded on the stage using a laser,

Passing the laser beam through a spherical lens having a plurality of curved surfaces and dividing the laser beam into a plurality of laser beams having different focal lengths;

Transmitting the plurality of divided laser beams through the object to form condensing spots at different depths; And

And moving the laser beam relative to the stage along a line to be processed to process the object to be processed.
The method of claim 7, wherein

And the curved surfaces of the spherical lens have different focal lengths.
The method of claim 7, wherein

And processing the object by moving the laser beam relative to the stage along the machining line, processing the object by moving the stage or scanning the laser beam.
In the laser processing apparatus for processing the object to be loaded on the stage using a laser,

A laser light source for emitting a laser beam;

And an optical system for dividing the laser beam into a plurality of laser beams to form condensing spots at different depths of the object.

And a condensing point formed at a position deeper from the plane on which the laser beam of the object is incident is formed on the moving direction of the laser beam at a line to be processed than a condensing point formed at a shallower position.
The method of claim 10,

The optical system includes a plurality of lenses having a different focal length from each other.
The method of claim 11,

And wherein the plurality of lenses have a focal length greater than that of a lens positioned in a movement direction of the laser beam in a direction opposite to the movement direction of the laser beam.
The method of claim 10,

The optical system is a laser processing apparatus comprising a diffraction optical element lens.
The method of claim 10,

And the stage moves relative to the laser beam to process the workpiece.
The method of claim 10,

And a scanner for moving the laser beam relative to the stage along the machining line.
In the laser processing apparatus for processing the object to be loaded on the stage using a laser,

A laser light source for emitting a laser beam;

And dividing the laser beam into a plurality of laser beams, the spherical lens having a plurality of curved surfaces to form condensing points at different depths of the workpiece.

The spherical lens is a laser processing device is formed of a plurality of curved surfaces having different focal lengths.
The method of claim 16,

The plurality of curved surfaces of the spherical lens has a different focal length.
The method of claim 16,

And the stage moves relative to the laser beam to process the workpiece.
The method of claim 16,

And a scanner for moving the laser beam relative to the stage along a machining line.