WO2017069389A1

WO2017069389A1 - Optical system aligning device and optical system aligning method for laser processing apparatus

Info

Publication number: WO2017069389A1
Application number: PCT/KR2016/009014
Authority: WO
Inventors: 김병오; 이동준
Original assignee: (주)이오테크닉스
Priority date: 2015-10-20
Filing date: 2016-08-17
Publication date: 2017-04-27
Also published as: TW201714692A; KR101720575B1; TWI610748B

Abstract

Disclosed are a device and method for aligning a laser optical system constituting a laser processing apparatus. The disclosed optical system aligning device for a laser processing apparatus comprises: a laser optical system through which a laser beam passes; a Shack-Hartmann sensor for measuring a light wavefront of the laser beam emitted from the laser optical system; and a computing unit for expressing the light wavefront of the laser beam detected by the Shack-Hartmann sensor in an equation, and calculating an eccentric value for the laser optical system, which arises when the laser optical system becomes misaligned.

Description

Optical system alignment device and optical system alignment method of laser processing equipment

The present invention relates to optical system alignment alignment of a laser processing apparatus, and more particularly, to an optical system alignment apparatus of a laser processing apparatus using a shark-hartman sensor and an optical system alignment method using the same.

A shack-hartmann sensor is a device that measures the distortion or aberration of the light wavefront reflected in a specific area in the field of astronomical telescopes and optometry, and uses the measured distortion or aberration of the light wavefront. It is generally used to measure the shape of the surface in a specific area. On the other hand, the optical system used in the laser processing apparatus needs to be correctly aligned so that the laser beam can be accurately irradiated in the desired direction to improve the processing quality.

An embodiment of the present invention provides an optical system alignment device and an optical system alignment method of a laser processing apparatus using a shark-hartman sensor.

In one aspect of the invention,

In the apparatus for aligning the laser optical system constituting the laser processing apparatus,

Laser optics via the laser beam:

A shark-hartmann sensor for measuring a light wavefront of the laser beam emitted from the laser optics; And

And a calculation unit for calculating an eccentricity of the laser optical system generated by misalignment of the laser optical system by expressing the optical wavefront of the laser beam detected by the Shark-Hartman sensor by a formula. An optical system alignment device is provided.

The calculator may calculate the eccentricity of the laser optical system using Zernike polynomials expressing the optical wavefront detected by the Shark-Hartman sensor as a formula.

The eccentricity value of the laser optical system is the eccentricity coefficient value in the first axis direction and the second axis direction indicating the degree of eccentricity in the first axis direction and the second axis direction perpendicular to the advancing direction of the laser beam in the Zernike polynomial. It may be composed of an eccentric coefficient value. Here, the first axis direction and the second axis direction may be perpendicular to each other.

Alignment of the laser optical system may be performed by moving the laser optical system such that the eccentricity coefficient value in the first axial direction and the eccentricity coefficient value in the second axial direction have “0” respectively.

The laser optical system may include a plurality of optical systems. In this case, alignment of the laser optical system may be performed by sequentially aligning each of the optical systems.

In another aspect of the invention,

In the method for aligning the laser optical system constituting the laser processing apparatus,

Measuring the laser beam via the laser optics using a Shark-Hartman sensor; And

Calculating an eccentricity value of the laser optical system generated by misalignment of the laser optical system by expressing an optical wavefront of the laser beam detected by the Shark-Hartman sensor by a formula; And

There is provided an optical system alignment method of a laser processing apparatus comprising; aligning the laser optical system.

The eccentric value of the laser optical system can be calculated using the Zernike polynomial which expresses the optical wavefront detected by the Shark-Hartmann sensor by a formula. Here, the eccentric value of the laser optical system is an eccentricity coefficient value and a second axis in the first axis direction indicating the degree of eccentricity in the first axis direction and the second axis direction perpendicular to the advancing direction of the laser beam in the Zernike polynomial It may consist of an eccentric coefficient value in the direction. .

The laser optical system may include a plurality of optical systems. In this case, alignment of the laser optical system may be performed by sequentially aligning each of the optical systems. Alignment of each of the optical systems may be performed by moving each of the optical systems such that the eccentricity coefficient value in the first axial direction and the eccentricity coefficient value in the second axial direction have “0” respectively.

According to an exemplary embodiment of the present invention, the Shark-Heartmann sensor can detect whether the laser optical system constituting the laser processing apparatus is misaligned, and if the laser optical system is misaligned, it can be accurately aligned. In addition, when the laser optical system includes a plurality of optical systems, the alignment operation may be sequentially performed on each of the optical systems using the Shark-Hartman sensor.

FIG. 1A shows a state in which a laser beam enters a Shark-Hartman sensor after passing through a converging optical system.

FIG. 1B shows a state in which the laser beam is incident on the Shark-Hartman sensor after passing through the diverging optical system.

FIG. 1C shows the laser beam entering the Shark-Hartman sensor after passing through the diverging and converging optics.

2 schematically shows an optical system alignment device of a laser processing apparatus according to an exemplary embodiment of the present invention.

FIG. 3 illustrates a change in an eccentric coefficient value in a first direction (eg, y-axis direction) according to a defocusing distance in the Zernike polynomial expressing a laser beam detected from a Shark-Hartman sensor.

4 schematically shows an example of a laser processing apparatus.

5A to 5C are views illustrating a method of aligning optical systems of the laser processing apparatus shown in FIG. 4.

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 a given layer of material is described as being in a substrate or other layer, the material layer may be in direct contact with the substrate or another layer, and another third layer may be present therebetween.

The shack-hartmann sensor is a device for measuring the distortion or aberration of the light wavefront reflected in a specific area in fields such as astronomical telescopes and optometry. In addition, the distortion or aberration of the optical wavefront measured by the Shark-Heartmann sensor is generally used to measure the shape of the surface in a specific region. In the embodiments of the present invention described below, an apparatus and method for aligning a laser optical system constituting a laser processing apparatus using a Shark-Hartman sensor will be described.

1A to 1C illustrate a state in which a laser beam is incident on a Shark-Heartman sensor after passing through a predetermined optical system.

Specifically, FIG. 1A shows the state where the laser beams L1 and L2 enter the Shark-Hartman sensor 50 after passing through the converging optical system 10, and FIG. 1B shows the laser beams L1 and L2. The incidence of the Shark-Hartman sensor 50 via the diverging optics 20 is shown. In addition, FIG. 1C shows a state in which the laser beam L1 enters the Shark-Hartman sensor 50 after passing through the diverging and converging optical system 30.

In FIGS. 1A and 1B, L1 represents a laser beam that is incident when the

optical systems

10 and 20 are correctly aligned, and L2 represents a first axis direction in which the

optical systems

10 and 20 are perpendicular to the traveling direction of the laser beam (eg, For example, the laser beam is incident in a misaligned state inclined at a predetermined angle along the y-axis direction. Meanwhile, FIG. 1C shows a laser beam that is incident when the optical system 30 is correctly aligned.

As shown in FIGS. 1A and 1B, when the laser beams L1 and L2 enter the Shark-Heartman sensor 50 via the

optical systems

10 and 20, the Shark-Heartman sensor 50 enters the incident laser. The optical wavefronts of the beams L1 and L2 are detected, and the optical wavefronts of the laser beams L1 and L2 thus detected are numerically calculated by a calculation unit as described below to determine whether the optical system is correctly aligned and, if misaligned, how misaligned. It can be known quantitatively.

Referring to FIG. 2, the optical system aligning apparatus 100 includes a laser optical system 140 through which the laser beam L passes, and a Shark-Heartmann sensor that detects the laser beam L via the laser optical system 140. 150 and an operation unit 160 for calculating an eccentric value of the laser optical system 140 by expressing the optical wavefront of the laser beam L detected from the Shark-Hartman sensor 150 by a formula.

The laser optical system 140 passes through a laser beam L emitted from a laser light source (not shown), and may include at least one optical system. The laser optical system 140 may include, for example, a beam expanding telescope (BET), a scanning optical system, a focusing lens, and the like. However, the present invention is not limited thereto, and other various optical systems may be included.

The laser beam L via the laser optical system 140 may be incident on the Shark-Heartmann sensor 150. Here, the Shark-Hartman sensor 150 may measure information about a light wavefront of the incident laser beam L, for example, a distortion or aberration of the light wavefront.

The calculation unit 160 may formulate information on the optical wavefront of the laser beam L detected by the Shark-Heartman sensor 150. Specifically, when the Shark-Heartmann sensor 160 detects information on the optical wavefront of the incident laser beam (L), it sends an electrical signal corresponding to the calculation unit 160. In addition, the calculator 160 may configure information on the optical wavefront of the laser beam L detected by the Shark-Hartman sensor 150 as Zernike polynomials, which are mathematical models. Here, the Zernike polynomial may consist of a number of terms, where each term constituting the Zernike polynomial represents optical aberrations, which terms are orthogonal to one another.

In the present embodiment, the calculation unit 160 expresses the information on the optical wavefront of the laser beam L by the Zernike polynomial, and then among the terms constituting the Zernike polynomial, the coefficient value representing the eccentricity in the first axis direction and the second The coefficient value representing the eccentricity in the axial direction can be used to determine whether the laser optical system is correctly aligned. In addition, the eccentricity of the laser optical system 140 generated when the laser optical system 140 is misaligned can also be known quantitatively.

The first axis direction and the second axis direction mean directions perpendicular to the advancing direction of the laser beam L. FIG. Here, the first axis direction and the second axis direction may be perpendicular to each other. As shown in FIG. 2, when traveling in the z-axis direction of the laser beam L, the first axis direction may be, for example, the y axis direction, and the second axis direction may be the x axis direction. . Therefore, when the laser beam L travels in the z-axis direction and is incident on the Shark-Hartman sensor 150, among the terms constituting the Zernike polynomial represented by the calculation unit 160, the aligned related protest of the laser optical system 140 is performed. The coefficient may include an eccentricity coefficient in the y-axis direction and an eccentricity coefficient in the x-axis direction. Here, the eccentricity coefficient in the y-axis direction represents an eccentricity value in the y-axis direction generated by tilting the laser optical system 140 in the y-axis direction, and the eccentricity coefficient in the x-axis direction indicates the laser optical system 140 in the x-axis direction. The eccentricity value in the x-axis direction generated by tilting is shown.

FIG. 3 shows an eccentricity coefficient in a first direction (eg, y-axis direction) according to a defocuse distance in the Zernike polynomial expressing the laser beam L detected from the Shark-Hartman sensor 150 as a formula. Value change is shown. Here, the defocus distance is the distance from the focused position to the Shark-Heartman sensor 150 when the laser beam L, which has exited the laser optical system 140, is focused and defocused to enter the Shark-Heartman sensor 150. Means.

3 shows that when the laser optical system 140 is inclined at an angle of 0 °, 0.01 ° and 0.02 ° in the first direction (y-axis direction), respectively, the first direction (y-axis) in the Zernike polynomial as the defocus distance is changed. Direction eccentric coefficient value change is shown. Referring to FIG. 3, when the laser optical system 140 is inclined at an angle of 0.01 ° and 0.02 ° in the first direction (y-axis direction), that is, when the laser optical system 140 is misaligned in the y-axis direction, It can be seen that the eccentricity coefficient value in the first direction (y-axis direction) changes linearly as the defocus distance changes. However, when the laser optical system is not tilted in the first direction (y-axis direction) (that is, when the laser optical system is correctly aligned in the y-axis direction), the eccentricity coefficient value in the first direction (y-axis direction) is defocused. It can be seen that it has a value of "0" regardless. Therefore, when the eccentricity coefficient value in the first direction (y-axis direction) is not a value of "0", it can be seen that the laser optical system 140 is inclined in the first direction and is eccentric.

In addition, when the laser optical system 140 is inclined in the second direction (x-axis direction), the eccentricity coefficient value of the second direction (x-axis direction) changes as the defocus distance is changed, and the laser optical system 140 When is not inclined in the second direction (x-axis direction), the eccentricity coefficient value in the second direction (x-axis direction) has a value of "0" regardless of the defocus distance. Therefore, when the eccentricity coefficient value in the second direction (x-axis direction) is not a value of "0", it can be seen that the laser optical system 140 is inclined in the second direction (x-axis direction) and eccentric.

As described above, the optical wavefront of the laser beam L incident on the Shark-Hartmann sensor 150 via the laser optical system 140 is constructed in a polynomial manner so that the eccentricity value of the first direction (y-axis direction) and the first By calculating the eccentricity value in one direction (y-axis direction), it is possible to know whether the laser optical system 140 is aligned, and if the laser optical system 140 is not properly aligned, it may be quantitatively determined how eccentrically.

Therefore, the eccentricity value of the first direction (y-axis direction) calculated by constructing the optical wavefront of the laser beam L incident on the Shark-Hartman sensor 150 by the polynomial through the laser optical system 140 and the first If at least one of the eccentric values in one direction (y-axis direction) is not "0", the laser optical system 140 may be precisely aligned by moving the laser optical system 140 so that the eccentric values become a value of "0". Can be.

4 schematically shows an example of a laser processing apparatus.

Referring to FIG. 4, the laser beam L is oscillated from the laser light source 201, and the laser beam L thus oscillated is reflected by the plurality of reflection mirrors 221, 222, and 223, and then enters the laser optical system 210. Can be. In the laser processing apparatus 200, the laser optical system 210 may include one or more

optical systems

211, 212, and 213. For example, the laser optical system 210 may include a BET, a scanning optical system, a focusing lens, and the like, and may include various other optical systems.

4 illustrates a case in which the laser optical system 210 includes three first, second, and third

optical systems

211, 212, and 213. As shown in FIG. 4, the laser beam L emitted from the laser light source 201 and reflected by the reflection mirrors 221, 222, and 223 passes through the first, second, and third

optical systems

211, 212, 213 sequentially. . In addition, the laser beam L emitted from the laser optical system 210 may be irradiated to a predetermined position of the processing target W loaded on the stage S to perform various processing operations.

In order to accurately perform the desired laser processing operation in the laser processing apparatus 200 having the above-described configuration, the laser optical system 210, ie, the first, second and third

optical systems

211, 212, 213 passing through the laser beam L, is correctly It must be aligned.

Hereinafter, a method of aligning the

optical systems

211, 212, 213 using the Shark-Hartman sensor in the laser processing apparatus 200 illustrated in FIG. 4 will be described. 5A to 5C are views illustrating a method of aligning optical systems of the laser processing apparatus shown in FIG. 4.

FIG. 5A illustrates a method of aligning the first optical system 211 of the laser optical system 210. Referring to FIG. 5A, the laser beam L emitted from the laser light source 201 and reflected by the reflection mirrors 221, 222, and 223 passes through the first optical system 211 and passes through the first optical system 211. One laser beam L is incident on the Shark-Heartmann sensor 250. Here, the Shark-Hartman sensor 250 detects information on the optical wavefront of the incident laser beam L, and sends this information to the calculator 260.

The calculation unit 260 configures Zernike polynomial information on the optical wavefront of the laser beam L via the first optical system 211 detected by the Shark-Hartman sensor 250. The eccentricity coefficient values in the first axis direction and the eccentricity coefficient values in the second axis direction are respectively calculated among the terms constituting the Zernike polynomial. As shown in FIG. 5A, when the laser beam L is incident on the Shark-Heartmann sensor 250 in the z-axis direction, the first axis direction may be the y axis direction, and the second axis direction is the x axis direction. This can be

As described above, when the eccentricity coefficient value in the first axis direction and the eccentricity coefficient value in the second axis direction calculated by the Zernike polynomial are “0”, the first optical system 211 is considered to be correctly aligned. Can be. However, when the eccentricity coefficient value in the first axis direction is not "0", the first optical system 211 may be considered to be eccentric by tilting in the first axis direction, and the eccentricity coefficient value in the second axis direction is " If not 0 ″, the first optical system 211 may be considered to be eccentric by tilting in the second axis direction.

Therefore, when at least one of the eccentricity coefficient value in the first axis direction and the eccentricity coefficient value in the second axis direction is not “0”, the first optical system 211 is misaligned. In this case, the first optical system 211 is used. ) So that the eccentricity coefficient value in the first axis direction and the eccentricity coefficient value in the second axis direction are both "0", thereby accurately aligning the first optical system 211.

5B illustrates a method of aligning the second optical system 212 of the laser optical system 210. In FIG. 5B the first optical system 211 is already correctly aligned using the method shown in FIG. 5A.

Referring to FIG. 5B, the laser beam L, which is emitted from the first optical system 211 and passes through the second optical system 212, is incident on the Shark-Heartman sensor 250. Here, the Shark-Hartman sensor 250 detects information on the optical wavefront of the incident laser beam L, and sends this information to the calculator 260.

The calculation unit 260 configures Zernike polynomial information on the optical wavefront of the laser beam L via the second optical system 212 detected by the Shark-Hartman sensor 250. The eccentricity coefficient values in the first axis direction (y-axis direction) and the eccentricity coefficient values in the second axis direction (x-axis direction) are respectively calculated from the terms constituting the Zernike polynomial.

Here, when at least one of the eccentricity coefficient value in the first axis direction and the eccentricity coefficient value in the second axis direction is not “0”, the second optical system 212 is misaligned, and in this case, the second optical system 212. ) So that the eccentricity coefficient value in the first axis direction and the eccentricity coefficient value in the second axis direction are both "0", thereby accurately aligning the second optical system 212.

FIG. 5C illustrates a method of aligning the third optical system 213 of the laser optical system 210. In FIG. 5C the first and

second optics

211, 212 are already correctly aligned using the method shown in FIGS. 5A and 5B.

Referring to FIG. 5C, the laser beam L, which is emitted from the first and second

optical systems

211 and 212 and passes through the third optical system 213, is incident on the Shark-Heartman sensor 250. Here, the Shark-Hartman sensor 250 detects information on the optical wavefront of the incident laser beam L, and sends this information to the calculator 260. The calculation unit 260 configures Zernike polynomial information on the optical wavefront of the laser beam L via the third optical system 213 detected by the Shark-Hartman sensor 250. The eccentricity coefficient values in the first axis direction (y-axis direction) and the eccentricity coefficient values in the second axis direction (x-axis direction) are respectively calculated from the terms constituting the Zernike polynomial.

Here, when at least one of the eccentricity coefficient value in the first axis direction and the eccentricity coefficient value in the second axis direction is not “0”, the third optical system 213 is misaligned. In this case, the third optical system 213 ) So that the eccentricity coefficient value in the first axial direction and the eccentricity coefficient value in the second axial direction are both “0” so that the third optical system 213 can be accurately aligned.

As described above, when the laser optical system 210 includes the plurality of

optical systems

211, 212, 213, all

optical systems

211, 212, 213 are sequentially aligned with each of the

optical systems

211, 212, 213 according to the order through which the laser beam L passes. ) Can be aligned correctly. Therefore, the laser processing apparatus 200 illustrated in FIG. 4 may accurately perform a desired laser processing operation by using the plurality of

optical systems

211, 212, and 213 accurately aligned. 5A to 5C, a case in which the laser optical system 210 includes three

optical systems

211, 212, and 213 has been described. However, the present exemplary embodiment is not limited thereto, and the laser optical system may include various numbers of optical systems.

As described above, according to exemplary embodiments of the present invention, the Shark-Heartmann sensor can detect whether the laser optical system constituting the laser processing apparatus is misaligned, and if the laser optical system is misaligned, it is accurately aligned. You can. In addition, when the laser optical system includes a plurality of optical systems, the alignment operation may be sequentially performed on each of the optical systems using the Shark-Hartman sensor. 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

In the apparatus for aligning the laser optical system constituting the laser processing apparatus,

Laser optics via the laser beam:

A shark-hartmann sensor for measuring a light wavefront of the laser beam emitted from the laser optics; And

And a calculation unit for calculating an eccentricity of the laser optical system generated by misalignment of the laser optical system by expressing the optical wavefront of the laser beam detected by the Shark-Hartman sensor by a formula. Optical alignment device.
The method of claim 1,

And the calculating unit calculates an eccentricity of the laser optical system using Zernike polynomials expressing the optical wavefront detected by the Shark-Hartman sensor as a formula.
The method of claim 2,

The eccentricity value of the laser optical system is the eccentricity coefficient value in the first axis direction and the second axis direction indicating the degree of eccentricity in the first axis direction and the second axis direction perpendicular to the advancing direction of the laser beam in the Zernike polynomial. Optical system alignment device of a laser processing device composed of eccentric coefficient value.
The method of claim 3, wherein

And the first axis direction and the second axis direction are perpendicular to each other.
The method of claim 3, wherein

The alignment of the laser optical system is an optical system alignment device of a laser processing apparatus, wherein the laser optical system is moved such that the eccentricity coefficient value in the first axial direction and the eccentricity coefficient value in the second axial direction are each "0".
The method of claim 3, wherein

The laser optical system is an optical system alignment device of a laser processing apparatus including a plurality of optical systems.
The method of claim 6,

Alignment of the laser optical system is an optical system alignment device of the laser processing apparatus is made by sequentially aligning each of the optical systems.
In the method for aligning the laser optical system constituting the laser processing apparatus,

Measuring the laser beam via the laser optics using a Shark-Hartman sensor; And

Calculating an eccentricity value of the laser optical system generated by misalignment of the laser optical system by expressing an optical wavefront of the laser beam detected by the Shark-Hartman sensor by a formula; And

Aligning the laser optical system; Optical system alignment method of a laser processing apparatus comprising a.
The method of claim 8,

Eccentricity value of the laser optical system is an optical system alignment method of the laser processing apparatus is calculated by using the Zernike polynomial expression expressed by the optical wavefront detected by the Shark-Hartman sensor.
The method of claim 9,

The eccentricity value of the laser optical system is the eccentricity coefficient value in the first axis direction and the second axis direction indicating the degree of eccentricity in the first axis direction and the second axis direction perpendicular to the advancing direction of the laser beam in the Zernike polynomial. An optical system alignment method of a laser processing apparatus composed of eccentric coefficient values.
The method of claim 10,

And the first axis direction and the second axis direction are perpendicular to each other.
The method of claim 10,

The alignment of the laser optical system is an optical system alignment method of a laser processing apparatus, wherein the laser optical system is moved so that the eccentricity coefficient value in the first axial direction and the eccentricity coefficient value in the second axial direction are respectively zero.
The method of claim 10,

The laser optical system is an optical system alignment method of a laser processing apparatus comprising a plurality of optical systems.
The method of claim 13,

Alignment of the laser optical system is an optical system alignment method of the laser processing apparatus is made by sequentially aligning each of the optical systems.
The method of claim 14,

And the alignment of each of the optical systems is performed by moving each of the optical systems such that the eccentricity coefficient value in the first axial direction and the eccentricity coefficient value in the second axial direction are each "0".