Laser optics system, adjustment procedure for this, laser processing device and procedure

Abstract

A laser optics system, an adjustment procedure for this system, a laser processing device, and a laser processing procedure, all of which meet the criteria for laser processing, are provided. The adjustment procedure for a laser optics system (14), which includes a plurality of optical element units (U1 to U3) arranged in series along an optical path of a laser light and each comprising a half-wave plate (WB1 to WB3) and a Wollaston prism (WP1 to WP3), wherein the laser optics system is configured to split the laser light incident through the half-wave plate onto the Wollaston prism into two beams of a branched laser light, comprises a step for rotating the half-wave plate about the optical path to adjust the branching ratios of the branched laser light and a step for rotating the Wollaston prism about the optical path to adjust branching directions of the branched laser light.

Description

Background of the inventionField of invention

[0001] The present invention relates to a laser optical system, an adjustment method thereof, a laser processing apparatus, and a laser processing method, and more particularly to a laser optical system, an adjustment method thereof, a laser processing apparatus, and a laser processing method for performing laser processing by irradiating a workpiece such as a semiconductor wafer with laser light. State of the art

[0002] For the production of a semiconductor device, it is known to provide a wafer (semiconductor wafer) on which components are formed as a stacked body obtained by stacking a low-dielectric-constant insulating film (low-k film) and a functional film forming circuits on a surface of a substrate made of, for example, silicon. On such a wafer, grid-shaped streets divide the components into a grid shape, with individual components being manufactured by dicing the wafer along planned division lines.

[0003] The low-k film is fragile and prone to chipping, so the low-k film may chip during dicing of the wafer using a blade, resulting in damage to the components. Given the fragile nature of the low-k film and its prone to chipping, a method is known in which two rows of a first groove dividing the low-k film are formed on both sides of a planned dividing line by laser ablation processing, and then a second groove is formed between the two rows of the first groove (see, for example, Patent Literature 1). Reference list

[0004] Patent Literature 1: Japanese Patent Laid-Open No. 2015-154009 Summary of the invention

[0005] The following evaluation criteria or standards (1) to (3) apply to the laser processing of a workpiece and the resulting processing result: (1) Laser processing should be able to be carried out within a short period of time. (2) The influence of heat on components and, for example, on chips should be suppressed. (3) A desired machining result (such as the depth of a machining groove, a depth position, or the size of a laser machining area) should be obtained.

[0006] To meet criteria (1) and (3) described above, a setting can be made so that laser processing can be performed in a single pass. However, if laser processing is performed in a single pass, the energy per beam must be increased, which increases the probability of heat generation during laser processing. Therefore, it is difficult to meet criterion (2): suppressing the influence of heat.

[0007] For example, to meet criterion (2): suppressing the influence of heat, it is considered effective to perform laser processing with multiple passes while simultaneously reducing the energy per beam. However, reducing the energy per beam results in an increase in the time required for laser processing, which makes it difficult to meet criterion (1).

[0008] The present invention takes these circumstances into account and aims to provide a laser optical system, an adjustment method therefor, a laser processing apparatus and a laser processing method that can adjust a laser light so as to satisfy the criteria for laser processing.

[0009] To solve the above-described problem, a laser optical system according to a first aspect of the present invention comprises: a plurality of optical element units arranged in a row on an optical path of a laser light, each including a half-wave plate and a Wollaston prism; a waveplate rotating mechanism configured to rotate each half-wave plate around the optical path; and a prism rotating mechanism configured to rotate each Wollaston prism around the optical path; wherein in each of the plurality of optical element units, the laser light is incident on the Wollaston prism through the half-wave plate and is branched into two beams of branched laser light.

[0010] According to a second aspect of the present invention, the laser optical system according to the first aspect includes a laser light adjusting unit configured to adjust the branching ratios of the branched laser light by rotating the half-wave plate using the wave plate rotating mechanism and to adjust the branching directions of the branched laser light by rotating the Wollaston prism using the prism rotating mechanism.

[0011] According to a third aspect of the present invention, the laser optical system according to the first or second aspect comprises an optical element unit moving mechanism configured to move each of the plurality of optical element units selectively between a set position at which the optical element unit is arranged on the optical path of the laser light and a retreat position at which the optical element unit is retreated from the optical path of the laser light.

[0012] According to a fourth aspect of the present invention, in the laser optical system according to any one of the first to third aspects, the waveplate rotating mechanism rotates the half-waveplate to differentiate the branching ratios of the branched laser light.

[0013] According to a fifth aspect of the present invention, in the laser optical system according to any one of the first to fourth aspects, the prism rotating mechanism rotates the Wollaston prism to adjust a machining width when laser machining is to be performed on a workpiece.

[0014] A laser processing apparatus according to a sixth aspect of the present invention includes: a laser light source configured to emit laser light; the laser optical system according to any one of the first to fifth aspects; and a condenser lens configured to focus the laser light branched by the laser optical system onto a workpiece.

[0015] A seventh aspect of the present invention provides an adjustment method for a laser optical system including a plurality of optical element units arranged in a row along an optical path of a laser light, each including a half-wave plate and a Wollaston prism, the laser optical system being configured to branch the laser light incident on the Wollaston prism into two beams of branched laser light through the half-wave plate. The adjustment method includes: a step of adjusting the branching ratios of the branched laser light by rotating the half-wave plate around the optical path; and a step of adjusting the branching directions of the branched laser light by rotating the Wollaston prism around the optical path.

[0016] A laser processing method according to an eighth aspect of the present invention includes a step of performing laser processing by irradiating a workpiece with laser light emitted from a laser optical system adjusted by the laser optical system adjustment method according to the seventh aspect.

[0017] According to the present invention, by adjusting the branching ratios and the branching directions of the branched laser light, the laser light can be adjusted to meet criteria of laser processing. Brief description of the drawings Fig. 1 is a schematic view of a laser processing apparatus according to an embodiment of the present invention. Fig. 2 is a plan view of a wafer to be processed. Fig. Figure 3 is an explanatory diagram explaining laser processing along an odd-numbered road. Fig. Figure 4 is an explanatory diagram explaining laser processing along an even-numbered road. Fig. Figure 5 is a block diagram showing an example of a laser optics system. Fig. 6A is a view showing an example of branching a laser light. Fig. 6B is a view showing an example of branching a laser light. Fig. 6C is a view showing an example of branching a laser light. Fig. 7A is a view showing an example of branching ratios of a laser light branched into eight beams (number of units: 3). Fig. 7B is a view showing an example of branching ratios of a laser light branched into eight beams (number of units: 3). Fig. 8 is a view showing an example of branching directions of a laser light branched into eight beams (number of units: 3). Fig. 9A is a view showing an example of branching directions of a laser light branched into four beams (number of units: 2). Fig. 9B is a view showing an example of branching directions of a laser light branched into four beams (number of units: 2). Fig. 10 is a flowchart showing a laser processing method according to an embodiment of the present invention. Fig. 11 is a flowchart showing an adjustment procedure of the laser optical system. Fig. 12 is a block diagram showing an example of the laser optical system in an adjustment of the laser optical system. Description of embodiments

[0018] Hereinafter, an embodiment of a laser optical system, an adjustment method thereof, a laser processing apparatus and a laser processing method of the present invention will be described with reference to the accompanying drawings. [Laser processing]

[0019] In this embodiment, to meet criteria (1) to (3) for laser processing, the energy per beam is kept low by branching the laser light into two beams for processing. Furthermore, single-pass laser processing is achieved by using laser light branched into multiple beams. This allows criteria (1) to shorten the time required for laser processing and (2) to suppress the influence of heat to be met.

[0020] A diffractive optical element (DOE), for example, can be used as a device for branching the laser light into beams. However, the diffractive optical element has low optical path efficiency, which significantly reduces the power of the branched laser light. Reducing the power of the laser light leads to an increase in the time required for laser processing, making it difficult to meet criterion (1).

[0021] A polarizing beam splitter (PBS) can be used as another device for branching the laser light into beams. However, with a polarizing beam splitter, the angle formed by the branched laser light is too large, making it difficult to adjust the optical path of the branched laser light.

[0022] To overcome these problems, the laser light is branched into beams using a Wollaston prism with high optical path efficiency. Furthermore, in this embodiment, the laser light is branched into four or more beams by combining Wollaston prisms. By branching the laser light into multiple beams using Wollaston prisms, the laser light can be adjusted while ensuring the power of the branched laser light, thus meeting the above criteria. [Laser processing device]

[0023] The following is an example of a laser processing device with reference to Fig. 1 described.

[0024] Fig. 1 is a schematic view of a laser processing apparatus according to an embodiment of the present invention. As shown in Fig. 1, a laser processing apparatus 1 performs laser processing (ablation groove formation) on a wafer W1 as a pre-process before dividing the wafer W1 into chips C (see Fig. 2). The X, Y, and Z directions in the drawing are perpendicular to each other. The X and Y directions are horizontal directions, while the Z direction is vertical. The X direction corresponds to a machining feed direction of the present invention.

[0025] Fig. 2 is a plan view of the wafer W1 to be processed. As shown in Fig. As shown in Figure 2, wafer W1 is a stacked body in which a low-k film and a functional film forming a circuit are stacked on a surface of a substrate made of silicon, for example. Wafer W1 is divided into regions by streets S (planned division lines) arranged in a grid pattern. A component D constituting chip C is provided in each of the divided regions.

[0026] The laser processing apparatus 1 performs laser processing on the wafer W1 along the streets S indicated by (1) to (4) in the drawings for each street to remove the low-k film, etc. on the substrate.

[0027] At this time, the laser processing apparatus 1 alternately switches between a relative movement direction for moving the laser optical system 14 described below relative to the wafer W1 in the X direction for each street S in order to reduce the cycle time required for laser processing the wafer W1.

[0028] For example, when laser machining is performed along odd-numbered streets S indicated by (1), (3) in the drawings, the laser optical system 14 is moved relative to the wafer W1 in an outgoing direction X1, which is a direction along the X direction. On the other hand, when laser machining is performed along even-numbered streets S indicated by (2), (4) in the drawings, the laser optical system 14 is moved relative to the wafer W1 in an opposite direction along the X direction, that is, in a return direction X2 opposite to the outgoing direction X1.

[0029] Fig. 3 is an explanatory view explaining laser processing along an odd-numbered road S. Fig. 4 is an explanatory view explaining laser processing along an even-numbered road S.

[0030] As in Fig. 3 and Fig. As shown in Figure 4, in this embodiment, trimming processing and hollowing processing are performed simultaneously (in parallel) as laser processing. The trimming processing is laser processing performed using two beams of a first laser light (split laser) L1 to form a trimming groove G1 (two rows of first groove, ablation grooves) consisting of two mutually parallel rows along the road S.

[0031] The hollowing processing is a laser processing for forming a hollow groove G2 (second groove, ablation groove) between the two rows of the cutting groove G1 formed by the trimming processing. In this embodiment, the hollowing processing is performed using a second laser light (line laser) L2 with a larger radius than the radius of the two beams of the first laser light L1.

[0032] In the laser processing apparatus 1, when the laser optical system 14 moves in the outgoing direction X1 and also moves in the returning direction X2 relative to the wafer W1, the dicing processing is performed before the hollowing processing.

[0033] As in Fig. 1, the laser processing apparatus 1 includes a control device 10, a first laser light source 12A, a second laser light source 12B, the laser optical system 14, a microscope 20, and a relative movement mechanism 22.

[0034] A stage ST is moved along the X-direction and the Y-direction by the relative movement mechanism 22 and rotated around the Z-axis under the control of the controller 10.

[0035] The first laser light source 12A emits laser light LA, which is a pulse laser light satisfying specific conditions (such as wavelength, pulse width, and repetition frequency) for cutting processing, to the laser optical system 14. The second laser light source 12B emits laser light LB, which is a pulse laser light satisfying specific conditions (such as wavelength, pulse width, and repetition frequency) for hollowing processing, to the laser optical system 14.

[0036] The laser optics system 14 forms two beams of first laser light L1 for cutting processing based on the laser light LA ​​from the first laser light source 12A. Further, the laser optics system 14 forms a beam of second laser light L2 for hollowing processing based on the laser light LB from the second laser light source 12B. Then, the laser optics system 14 emits (irradiates) the two beams of first laser light L1 toward the road S from a first condenser lens 16. Further, the laser optics system 14 selectively emits (irradiates) the second laser light L2 toward the road S from a second condenser lens 18B under the control of the controller 10.

[0037] Furthermore, the laser optical system 14 is moved in the Y direction and the Z direction by the relative movement mechanism 22 under the control of the controller 10.

[0038] The microscope 20 is fixed to the laser optical system 14 and moves together with the laser optical system 14. The microscope 20 captures an image of an alignment reference (not shown) formed on the wafer W1 before the dicing processing and the hollowing processing. Furthermore, the microscope 20 captures an image of the two rows of the dicing groove G1 and the hollowing groove G2 formed along the road S by the dicing processing and the hollowing processing. The images (image data) captured by the microscope 20 are output to the controller 10 and displayed by the controller 10 on a monitor (not shown).

[0039] The relative movement mechanism 22, which includes an XYZ actuator and a motor, moves the stage ST in the X and Y directions, rotates the stage ST about a rotation axis, and moves the laser optical system 14 in the Z direction under the control of the controller 10. In this way, the relative movement mechanism 22 can move the laser optical system 14 relative to the stage ST and the wafer W1. As long as the laser optical system 14 can be moved in the respective directions (including rotation) relative to the stage ST (the wafer W1), no particular restrictions are imposed here on the relative movement method.

[0040] The relative movement mechanism 22 is driven to perform position adjustment (alignment) of the laser optical system 14 with respect to a processing start position at one end of the road S of the processing target and relative movement of the laser optical system 14 in the X direction (the outgoing direction X1 or the returning direction X2) along the road S. Furthermore, the relative movement mechanism 22 is driven to rotate the stage ST by 90 degrees, so that each road S can be provided along the Y direction of the wafer W1 parallel to the X direction, which is the processing feed direction.

[0041] The control device 10 is, for example, a personal computer. The control device 10 includes various types of processors (such as a central processing unit (CPU) and a graphics processing unit (GPU)), a memory, and a storage device. Note that various functions of the control device 10 can be implemented by a single processor or by multiple processors of the same type or different types. The control device 10 controls the operation of the first laser light source 12A, the second laser light source 12B, the laser optical system 14, the microscope 20, the relative motion mechanism 22, etc. [Laser optics system]

[0042] An example of the laser optics system 14 is described below with reference to Fig. 5 described. Fig. 5 is a block diagram showing an example of an illumination optical system. In the following description, an example in which the laser light LB branches from the second laser light source 12B will be described, but the invention can also be applied to the laser light LA. The branching of the laser light B on the second condenser lens 18A side and on the second condenser lens 18B side are similar, so the second condenser lenses 18A and 18B will be referred to simply as one condenser lens 18 in the following description.

[0043] In the laser optics system 14 of Fig. 5, within the optical element units U1 to U2 for branching the laser light LB, two or more optical element units are selectively placed on or removed from an optical path of the laser light LB to arrange the two or more optical element units in series on the optical path, thereby enabling output of a branched laser light.

[0044] Fig. 5 shows the optical path of the laser light LB from a laser head LH of the second laser light source 12B to the workpiece W.

[0045] The laser head LH outputs the laser light LB emitted by a laser oscillator of the second laser light source 12B.

[0046] As in Fig. 5, as examples of optical elements for adjusting the laser light LB, an attenuator ATN, a beam expander BE and a beam shaping element BF are arranged between the laser head LH and the optical element units U1 to U3.

[0047] The attenuator ATN is an optical element for adjusting (attenuating) the level of the laser light LB to an appropriate level (amplitude).

[0048] The beam expander BE is an optical element for adjusting (expanding) the beam diameter of the laser light LB and for forming a collimated light (parallel light) from the laser light LB.

[0049] The beam shaping element BF is an optical element for adjusting a beam profile (such as a shape of the beam and an intensity distribution of the beam) of the laser light LB.

[0050] As in Fig. As shown in Figure 5, the optical element units (hereinafter referred to as "units") U1 to U3 for branching the laser light LB are arranged between the above-described optical elements for adjusting the laser light LB and the condenser lens 18. The optical element units U1 to U3 each include: half-wave plates (λ / 2 wave plates) WB1 to WB3 and Wollaston prisms WP1 to WP3.

[0051] The half-wave plates WB1 to WB3 are optical elements containing birefringent materials. The half-wave plates WB1 to WB3 generate a phase difference of 180 degrees between the orthogonal polarization components of the laser light LB. When linearly polarized light is incident on the half-wave plates WB1 to WB3 at an angle θ with respect to the optical axes of the half-wave plates WB1 to WB3, the linearly polarized light is emitted with a vibration direction rotated by 2θ.

[0052] Wollaston prisms WP1 to WP3 each branch a beam of laser light LB incident through half-wave plates WB1 to WB3 into two beams. In other words, Wollaston prism WP1 branches one beam of laser light LB into two beams, Wollaston prism WP2 branches the branched two beams of laser light LB into four beams, and Wollaston prism WP3 branches the branched four beams of laser light LB into eight beams.

[0053] In this embodiment, the number of beams to be branched from the laser light LB can be adjusted by changing the number of units U1 to U3 on the optical path of the laser light LB.

[0054] The half-wave plates WB1 to WB3 are arranged on an upstream side of the Wollaston prisms WP1 to WP3 in the corresponding units U1 to U3 and are used for adjusting the energy ratios of the branched laser light LB.

[0055] The laser light LB branched through the units U1 to U3 is focused onto the workpiece W by the condenser lens 18.

[0056] An adjustment mechanism 50 controls the units U1 to U3 according to a control signal from the controller 10. The adjustment mechanism 50 includes a drive unit (a waveplate rotating mechanism) and a prism rotating mechanism. For example, a mechanism (a stage) for holding optical elements and an actuator or the like are provided for controlling the angles of the half-wave plates WB1 to WB3 included in the units U1 to U3 and for controlling the positions and angles of the Wollaston prisms WP1 to WP3. Furthermore, the adjustment mechanism 50 includes a retraction control mechanism (an optical element unit moving mechanism).For example, a ball screw mechanism, an actuator, or the like is provided for moving the units U2 and U3 between an insertion position and a retraction position on the optical path of the laser light LB, so that the units U2 and U3 are inserted into or removed from the optical path (retracted). In other words, the control device 10 and the adjustment mechanism 50 function as a laser light adjustment unit.

[0057] The adjustment mechanism 50 can adjust the energy intensity of the laser light LB branched into four beams or eight beams by rotating the half-wave plates WB1 to WB3 around the optical path of the laser light LB. Furthermore, the adjustment mechanism 50 can adjust the emission direction (branching direction) of the laser light LB branched into four beams or eight beams by rotating the Wollaston prisms WP1 to WP3 around the optical path of the laser light LB.

[0058] It should be noted that the number and arrangement of units U1 to U3 are not limited to the Fig. 5, and four or more units may be provided (the laser light can be branched into 16 or more beams). In this embodiment, the downstream side units U2 and U3 are configured to be retractable (removable) from the optical path of the laser light LB, and generally, any of the three units U1 to U3 may be retractable. [Example of branching laser light]

[0059] The following describes an example of branching the laser light LB (the number of beams to be branched, the branching ratios and the branching directions).

[0060] Fig. 6A, Fig. 6B and Fig. 6C are views showing examples of branching of the laser light. Fig. 6A, Fig. 6B and Fig. 6C show examples in which the laser light LB is branched by the units U1 to U3 into two beams, four beams, and eight beams, respectively. In the examples of Fig. 6A, Fig. 6B and Fig. 6C, points of branched laser light are arranged linearly along the machining progress direction (machining feed direction). By changing the number of units U1 to U3 for adjusting the number of beams to be branched, laser machining can be performed in one pass or in a reduced number of passes while still reducing the energy intensity per beam. Therefore, criterion (1): shortening the time required for laser machining and criterion (2): suppressing the influence of heat can be met. (Example of setting branching ratios)

[0061] Fig. 7A and Fig. 7B are views showing examples of branching ratios of a laser light branched into eight beams (number of units: 3).

[0062] Fig. Figure 7A shows an example in which the branching ratios of the laser light LB branched into eight beams are set equal. If in the example shown in Fig. In the example shown in Figure 7A, when the total energy (intensity) of the laser light branched into eight beams is set to 100%, the energy of each branched beam of laser light is 12.5%.

[0063] Fig. Fig. 7B shows an example in which the branching ratios of the laser light LB branched into eight beams are provided differently. In the example of Fig. 7B, the total energy (intensity) of the eight-beam branched laser light is set to 100%, the energy of four branched beams of laser light on the downstream side along the machining progress direction is 10%, and the energy of four branched beams of laser light on the upstream side is 15%.

[0064] It should be noted that the branching ratios are not limited to those mentioned above and can also be provided differently within the eight branched beams of the laser light.

[0065] As described above, by appropriately allocating energy for irradiation onto a surface of the workpiece W by providing different branching ratios of the branched laser light, the criterion (2): suppressing the influence of heat can be more effectively met. (Example of setting the branch directions)

[0066] Fig. 8 is a view showing an example of branching directions of the laser light branched into eight beams (number of units: 3).

[0067] In the example of Fig. 8, four branched beams of laser light are provided on the downstream side and four branched beams of laser light on the upstream side along the machining progress direction, and the four branched beams of laser light on the downstream side are offset from the four branched beams of laser light on the upstream side in a direction perpendicular to the machining progress direction. As described above, by adjusting the branching directions, a machining width on the surface or inside of the workpiece W can be adjusted. For example, a machining groove or the like with a large width W1 in a direction perpendicular to the machining progress direction can be formed in a single pass.

[0068] It should be noted that the branching directions do not correspond to those of the example of Fig. 8 and the positions of the points of the branched laser light can also be provided alternately for one beam or for each of two beams.

[0069] Fig. 9A and Fig. 9B are views showing examples of the branching directions of the laser light branched into four beams (number of units: 2). Fig. 9A and Fig. 9B each show cases where two of the units U1 and U2 are arranged on the optical path of the laser light LB.

[0070] Fig. 9A shows an example in which the positions of the points of the branched laser light are arranged linearly. In the example of Fig. 9A, two branched beams of laser light overlap each other at the position of the point in the center in the X direction.

[0071] Fig. Figure 9B shows an example in which the positions of the points of the branched laser light are arranged in a matrix form of 2 × 2 in the X and Y directions. The point arrangement of Fig. 9B is obtained by rotating the relative angle of rotation between the Wollaston prisms WP1 and WP2 by 90 degrees with respect to the angle of Fig. 9A received.

[0072] As described above, by adjusting the branching directions of the branched laser light, the criterion (3): obtaining a desired machining result (such as the depth of a machining groove or a depth position or a size of a laser machining area) can be satisfied.

[0073] Furthermore, by appropriately assigning the positions and energies of the points of the branched laser light on the workpiece W, criterion (1): shortening the time required for laser processing and criterion (2): suppressing the influence of heat can be met. For example, by adjusting the branching ratios and branching directions of the branched laser light, cutting processing can be performed in a single pass.

[0074] In the embodiment described above, the number of beams to be branched is limited to 2 N in relation to the number of units N, but the present invention is not limited thereto. As in Fig. 9A, by setting the branching directions of branched beams of the laser light such that a part of the branched laser light is superimposed, the number, positions, and intensities of spots on the workpiece W or inside the workpiece W can be arbitrarily changed. [Laser processing method]

[0075] Hereinafter, an adjustment method and a laser processing method of the laser optical system 14 according to the embodiment will be described with reference to Fig. 10 to Fig. 12 described.

[0076] In this embodiment, as in Fig. 10, after adjusting the laser optical system 14 and adjusting the branching ratios and branching directions of the branched laser light (step S10), laser processing is performed (step S12).

[0077] An adjustment process (step S10) of the laser optical system 14 will be described below with reference to Fig. 11 described.

[0078] In the adjustment process of the laser optics system 14, first as shown in Fig. 11 shown the number 2 N of the beams to be branched by the laser light is set. That is, the number N of units U1 to U3 to be used for branching the laser light is set (step S100). In the example of Fig. 5 N is 2 or 3 (the number of rays to be branched is 4 or 8).

[0079] Then, the branching ratios and the branching directions are sequentially set by the unit U1 on the upstream side (steps S102 to S108).

[0080] The adjustment of the units U1 to U3 according to this embodiment is carried out by installing a condenser lens F for adjustment, an attenuator ATN2 and an image pickup element IE on the downstream side of the units U1 to U3 as shown in Fig. 12 shown.

[0081] Because the angle formed by the laser light branched by units U1 to U3 is very small, the branched laser light is essentially parallel. The adjustment condenser lens F is an optical element for focusing the laser light branched by units U1 to U3, clarifying and adjusting the components of each beam of the branched laser light.

[0082] The attenuator ATN2 is an optical element for adjusting (attenuating) the level of the branched laser light incident on the image pickup element IE to an appropriate level (amplitude).

[0083] The image pickup element (IE) is an optical element for capturing a point image of the branched laser light. The image pickup element (IE) is, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0084] When unit U1 is set to the most upstream side, units U2 and U3 are retracted from the optical path. Then, a spot image of the two branched beams of laser light from unit U1 is captured by the image pickup element IE.

[0085] The controller 10 then calculates the branching ratios (intensities) and branching directions (positions) of the branched laser light from the spot image. The controller 10 then controls the adjustment mechanism 50 to rotate the half-wave plate WB1 to obtain the desired branching ratios and to rotate the Wollaston prism WP1 to obtain the desired branching directions.

[0086] Once the adjustment of unit U1 is completed, unit U2 is placed on the optical path and adjusted. In other words, a spot image of four branched beams of laser light from unit U2 is captured by image pickup element IE, and half-wave plate WB2 and Wollaston prism WP2 are rotated by adjustment mechanism 50 to obtain desired branching ratios and branching directions.

[0087] Then, steps S104 to S108 are repeated, and when the setting for all N units is completed (step S106: NO), the setting process for the laser optical system 14 is ended.

[0088] As described above, by sequentially performing the adjustment from the unit U1 on the upstream side, a branched laser light having desired branching ratios and branching directions can be obtained.

[0089] In this embodiment, the half-wave plates WB1 to WB3 and the Wollaston prisms WP1 to WP3 are automatically adjusted by the adjustment mechanism 50, but manual adjustment of the half-wave plates WB1 to WB3 and the Wollaston prisms WP1 to WP3 may also be enabled. For example, the dot images captured by the image pickup element IE may be output to a monitor, and an operator may manually operate and adjust the adjustment mechanism 50 while observing the dot image on the monitor.

[0090] Furthermore, in this embodiment, the unit on the upstream side is adjusted in a state where the unit on the downstream side is retracted from the optical path, but the invention is not limited to this. For example, when adjusting each unit, the image pickup element IE may be moved between the corresponding units in a state where the corresponding units to be used for laser processing are placed on the optical path. List of reference symbols 1 laser processing device 10 Control device 12A first laser light source 12B second laser light source 14 Laser optics system 16 first condenser lens 18A, 18B second condenser lens 20 microscope 22 Relative motion mechanism 50 Adjustment mechanism LH laser head ATN, ATN2 damper BE beam expander BF beam shaping element WP1 to WP3 Wollaston Prism WB1 to WB3 half-wave plate IE image capture element QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2015-154009

[0004]

Claims

[1] Laser optics system comprising: a plurality of optical element units arranged in series along an optical path of a laser light and each including a half-wave plate and a Wollaston prism, a waveplate rotating mechanism configured to rotate each half-waveplate around the optical path, and a prism rotating mechanism configured to rotate each Wollaston prism around the optical path, wherein in each of the plurality of optical element units, the laser light is incident on the Wollaston prism through the half-wave plate and is branched into two beams of branched laser light. [2] A laser optics system according to claim 1, comprising: a laser light adjusting unit configured to adjust the branching ratios of the branched laser light by rotating the half-wave plate using the waveplate rotating mechanism and to adjust the branching directions of the branched laser light by rotating the Wollaston prism using the prism rotating mechanism. [3] A laser optics system according to claim 1 or 2, comprising: an optical element unit moving mechanism configured to move each of the plurality of optical element units selectively between a set position where the optical element unit is arranged on the optical path of the laser light and a retreat position where the optical element unit is retreated from the optical path of the laser light. [4] The laser optical system according to any one of claims 1 to 3, wherein the waveplate rotating mechanism rotates the half-wave plate to differentiate the branching ratios of the branched laser light. [5] The laser optical system according to any one of claims 1 to 4, wherein the prism rotating mechanism rotates the Wollaston prism to adjust the machining width when laser machining is to be performed on a workpiece. [6] Laser processing device, comprising: a laser light source configured to emit a laser light, the laser optics system according to one of claims 1 to 5, and a condenser lens configured to focus the laser light branched by the laser optics system onto a workpiece. [7] An adjustment method for a laser optical system comprising a plurality of optical element units arranged in series on an optical path of a laser light and each including a half-wave plate and a Wollaston prism, the laser optical system being configured to branch the laser light incident on the Wollaston prism through the half-wave plate into two beams of branched laser light, the adjustment method comprising: a step of adjusting the branching ratios of the branched laser light by rotating the half-wave plate around the optical path, and a step of adjusting the branching directions of the branched laser light by rotating the Wollaston prism around the optical path. [8] Laser processing methods comprising: a step of performing laser processing by irradiating a workpiece with laser light emitted from a laser optical system adjusted by the laser optical system adjusting method of claim 7.

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