CN114074216A - Laser processing apparatus and laser processing method - Google Patents

Abstract

The laser processing device is configured to execute: a1 st process of generating a1 st branching pattern based on a predetermined calculation formula and displaying the generated 1 st branching pattern on the reflective spatial light modulator; a2 nd process of controlling the light source unit to emit laser light; a 3 rd process of controlling the detection unit to detect the reflected light of each laser beam branched by the 1 st branching pattern; a 4 th process of deriving actual output measurement values of the branched laser beams and generating a balance parameter for generation of a2 nd branch pattern, which is a branch pattern in which the actual output measurement values are close to the target output values; and a 5 th step of correcting the calculation formula according to the balance parameter, generating a2 nd branch pattern based on the corrected calculation formula, setting the pattern, and displaying the pattern on the reflective spatial light modulator for use in the processing.

Description

Laser processing apparatus and laser processing method

Technical Field

The present invention relates to a laser processing apparatus and a laser processing method.

Background

Japanese patent No. 6620976 describes a laser processing apparatus including a laser light source, a spatial light modulator, and a light-converging correction unit different from the spatial light modulator. Such a laser processing apparatus divides and peels an object by forming a modified region inside the object (wafer) by irradiation of laser light. In the technique described in patent document 1, a modified region is formed inside an object by irradiation of laser light, a part of reflected light from a converging point is imaged, the amount of positional deviation of the converging point is detected based on the imaging result, and a modulation pattern in a spatial light modulator is adjusted so that the positional deviation is reduced.

Disclosure of Invention

In the laser processing apparatus as described above, a branching pattern is set in the spatial light modulator, and the laser light may be branched in accordance with the branching pattern to simultaneously form a plurality of modified regions. The branching pattern is set, for example, in accordance with the output target value of each laser beam after branching. Here, for example, when laser light is branched using a spatial light modulator, the output of each laser light after branching does not reach the above-described output target value (design value) due to the influence of optical characteristics such as the difference between the optical characteristics of the spatial light modulator itself and the transmission regions of each branched light in the lens, or the individual difference of the optical elements. Such a phenomenon is difficult to completely avoid. Since the output of each laser beam after branching does not reach an assumed value, the amount of fractures extending from the modified region does not reach a desired amount of fractures, and there is a possibility that the object is not divided and does not peel (the processing quality is deteriorated). Therefore, an object of the present invention is to provide a laser processing apparatus and a laser processing method capable of improving processing quality by adjusting the output of the branched light to a desired value.

A laser processing apparatus according to an aspect of the present invention is a laser processing apparatus for forming a modified region in an object by irradiating the object with laser light, including: a light source for emitting laser light; a spatial light modulator for modulating laser light emitted from the light source; a detection unit for detecting the reflected light of the laser beam of the object; and a control unit configured to execute: a1 st process of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation algorithm, setting the generated 1 st branching pattern, and displaying the set 1 st branching pattern on the spatial light modulator; a2 nd process of controlling the light source so that the laser light is emitted in a state where the spatial light modulator displays the 1 st branching pattern; a 3 rd process of controlling the detection section to detect the reflected light of each laser light after branching by the 1 st branching pattern; a 4 th process of deriving an output actual measurement value of each laser beam after branching based on a detection result of the detection unit, generating a correction calculation algorithm, and generating a correction parameter for generation of a2 nd branch pattern as a branch pattern for bringing the output actual measurement value close to an output target value; and a 5 th process of correcting the calculation algorithm according to the correction parameter, generating a2 nd branch pattern based on the corrected calculation algorithm, and setting and displaying the generated 2 nd branch pattern on the spatial light modulator for the processing process.

In the laser processing apparatus according to one aspect of the present invention, the laser beam is emitted in a state where the 1 st branch pattern generated from the output target value of each laser beam after branching is displayed on the spatial light modulator, the reflected light from the object is detected, and the output actual measurement value of each laser beam is derived based on the detection result. Then, in the laser processing apparatus, the correction parameter for generating the 2 nd branch pattern for bringing the output measured value close to the output target value is generated, the 2 nd branch pattern is generated by the calculation algorithm corrected by the correction parameter, and the 2 nd branch pattern is displayed on the spatial light modulator to be used in the processing. According to such a configuration, the correction parameter for generating the 2 nd branch pattern for bringing the output actual measurement value estimated with high accuracy based on the actually detected reflected light close to the output target value is generated. Therefore, during the machining process, the calculation algorithm is corrected by the correction parameter to generate the 2 nd branching pattern that can bring the output of the branching light closer to the output target value than the 1 st branching parameter, whereby the output of the branching light can be appropriately adjusted to a desired value. As described above, according to the laser processing apparatus according to one aspect of the present invention, the output of the branched light can be adjusted to a desired value, and the processing quality can be improved.

The control unit may generate a plurality of types of 1 st branching patterns having different combinations of the output target values of the laser beams after branching in the 1 st processing, and generate a common correction parameter for at least 21 st branching patterns included in the plurality of types of 1 st branching patterns in the 4 th processing. In this way, by generating a common correction parameter for a plurality of 1 st branch patterns having different conditions for outputting the target value, it is possible to generate the 2 nd branch patterns each unique using the same correction parameter, and it is possible to facilitate the generation processing and management of the correction parameter compared to the case where the correction parameter is generated for each 1 st branch pattern.

In the 4 th process, the control unit may group the plurality of types of 1 st branching patterns according to the approximation degree of the branching parameter, and generate a common correction parameter for each group. For example, even when 1 correction parameter common to all the 1 st branch patterns is generated, and when the 1 st branch patterns and the like having the branch parameters greatly different from each other are included, the accuracy of all the 2 nd branch patterns (the accuracy of bringing the output of the branch light close to the output target value) cannot be sufficiently improved by correcting the calculation algorithm using the generated common correction parameter. In this regard, by generating a common correction parameter for each group to which the branch parameter is approximated, that is, generating another correction parameter between groups to which the branch parameter is not approximated, it is possible to ensure the accuracy of the 2 nd branch pattern (the accuracy with which the output of the branch light is brought close to the output target value).

In the 4 th process, the control unit may perform grouping according to the degree of approximation of the output target value as the branch parameter. Thus, since the common correction parameter is generated in units of groups whose output target values are approximate, the accuracy of the 2 nd branch pattern (the accuracy of bringing the output of the branch light close to the output target value) can be ensured.

In the 5 th process, the control unit may acquire information indicating a branch parameter in the machining process, and may correct the calculation algorithm based on a correction parameter of a group corresponding to the branch parameter. Thus, the 2 nd branch pattern generated by the calculation algorithm after correction of the correction parameter suitable for the branch parameter in the machining process can be displayed to perform the machining process, and the machining quality can be improved.

The control unit may generate a1 st branching pattern for branching the laser beam to different positions in a vertical direction, which is a thickness direction of the object, in the 1 st processing. In actual processing, there are cases where the laser beam branches off at different positions in the vertical direction (vertical branching), and by generating the 1 st branching pattern relating to this vertical branching, it is possible to generate correction parameters relating to the generation of the 2 nd branching pattern that can appropriately bring the output of the branched light in the case of vertical branching close to the output target value.

A laser processing method according to an aspect of the present invention is a laser processing method for forming a modified region in an object by irradiating the object with laser light, including: a1 st step of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation algorithm, and setting and displaying the generated 1 st branching pattern on a spatial light modulator; a2 nd step of emitting laser light to the spatial light modulator on which the 1 st branch pattern is displayed, and irradiating the object with the laser light branched into a plurality of parts according to the 1 st branch pattern; a 3 rd step of detecting reflected light from the object of each of the branched laser beams; a 4 th step of deriving an output actual measurement value of each laser beam after branching based on a detection result of the reflected light, and generating a correction calculation algorithm as a correction parameter for generating a2 nd branch pattern which is a branch pattern for bringing the output actual measurement value close to the output target value; and a 5 th step of correcting the calculation algorithm according to the correction parameters, generating a2 nd branch pattern based on the corrected calculation algorithm, and setting and displaying the generated 2 nd branch pattern on the spatial light modulator for use in the processing.

A laser processing method according to another aspect of the present invention includes: a1 st step of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation algorithm, and setting and displaying the generated 1 st branching pattern on a spatial light modulator; a2 nd step of emitting laser light to the spatial light modulator on which the 1 st branching pattern is displayed, and measuring the laser light branched into a plurality of parts by the 1 st branching pattern by a power meter to derive actual output measurement values of the branched laser lights; and a 3 rd step of generating and outputting a correction calculation algorithm as a correction parameter for generating a2 nd branch pattern as a branch pattern for bringing an output measured value close to an output target value.

In the laser processing method according to another aspect of the present invention, the laser light is emitted in a state where the 1 st branching pattern set based on the output target value of each laser light after branching is set in the spatial light modulator, the laser light branched into a plurality of pieces by the 1 st branching pattern is measured by the power meter, and the actual output measurement value of each laser light after branching is derived based on the measurement result. Then, in the present laser processing method, the correction parameter for generating the 2 nd branch pattern in which the output measured value is close to the output target value is generated and output. According to such a configuration, the correction parameter for generating the 2 nd branch pattern for bringing the output measured value actually measured by the power meter close to the output target value is generated. In this way, by generating a correction parameter so that the actually measured output approaches the target value, and correcting the calculation algorithm by the correction parameter at the time of the machining process, the 2 nd branch pattern capable of bringing the output of the branch light closer to the output target value than the 1 st branch parameter is generated, and thereby the output of the branch light can be appropriately adjusted to a desired value. As described above, according to the laser processing method according to one aspect of the present invention, the output of the branched light can be adjusted to a desired value, and the processing quality can be improved.

In the laser processing method according to the other aspect described above, in the step2, a light-shielding output measurement process of performing output measurement by a power meter while shielding a part of each of the branched laser beams by a light shielding plate may be performed, and in the light-shielding output measurement process, the output measurement may be performed by the power meter while changing a range of the laser beams shielded by the light shielding plate. In this way, by measuring the output of each laser beam by the power meter while changing the range of the laser beam blocked by the light blocking plate, the output of each laser beam after branching can be appropriately derived.

According to the present invention, the processing quality can be improved by adjusting the output of the branched light to a desired value.

Drawings

Fig. 1 is a perspective view of a laser processing apparatus according to an embodiment.

Fig. 2 is a front view of a part of the laser processing apparatus shown in fig. 1.

Fig. 3 is a front view of a laser processing head of the laser processing apparatus shown in fig. 1.

Fig. 4 is a side view of the laser processing head shown in fig. 3.

Fig. 5 is a structural diagram of an optical system of the laser processing head shown in fig. 3.

Fig. 6 is a plan view for explaining a plurality of modified light spots.

Fig. 7 is a diagram showing an example of a GUI setting screen.

Fig. 8 is a diagram showing an example of the administrator mode of the GUI setting screen.

Fig. 9 is a table showing the error of the actual measurement value with respect to the design value in each output ratio at the 2-point branching.

Fig. 10 is a table showing the error of the actual measurement value with respect to the design value in each output ratio at the 3-point branching.

Fig. 11 is a table showing the error of the actual measurement value with respect to the design value in each output ratio at the 4-point branching.

Fig. 12 is a diagram illustrating a vertical branching mode.

Fig. 13 is a table showing the error of the actual measurement value with respect to the design value at each output ratio when the balance parameter acquired without vertical branching is applied to the machining with vertical branching (VD 16).

Fig. 14 is a table showing the error of the actual measurement value with respect to the design value at each output ratio when the balance parameter acquired when the vertical branch (VD16) is present is applied to the machining with the vertical branch (VD 16).

Fig. 15 is a table showing the relationship between the vertical branch amount and the maximum error.

Fig. 16 is a table showing the error of the measured value with respect to the design value at each output ratio in the case where the balance parameter is applied to each region.

Fig. 17 is a diagram illustrating an operation of a balance parameter corresponding to a branch parameter.

Fig. 18 is a diagram illustrating the operation of the balance parameter corresponding to the branch parameter.

Fig. 19 is a flowchart illustrating a branch pattern generation process to which a balance parameter is applied.

Fig. 20 is a flowchart illustrating a branch pattern generation process to which a balance parameter is applied.

Fig. 21 is a schematic configuration diagram of a laser processing apparatus according to a modification.

Fig. 22 is a diagram illustrating output derivation of each laser beam after branching using a power meter.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and redundant description thereof is omitted.

First, a basic configuration of a laser processing apparatus will be described.

[ basic Structure of laser processing apparatus ]

As shown in fig. 1, the laser processing apparatus 1 includes a plurality of moving mechanisms 5, 6, a support 7, a pair of laser processing heads 10A, 10B, a light source unit 8, and a control section 9. In addition, although the following description will be given of an example in which the laser processing heads are a pair, the number of the laser processing heads may be only 1. Hereinafter, the 1 st direction is referred to as an X direction, the 2 nd direction perpendicular to the 1 st direction is referred to as a Y direction, and the 3 rd direction perpendicular to the 1 st direction and the 2 nd direction is referred to as a Z direction. In the present embodiment, the X direction and the Y direction are horizontal directions, and the Z direction is a vertical direction.

The moving mechanism 5 has a fixed portion 51, a moving portion 53, and a mounting portion 55. The fixing portion 51 is attached to the apparatus frame 1 a. The moving unit 53 is attached to a rail provided in the fixed unit 51 and is movable in the Y direction. The mounting portion 55 is mounted on a rail provided in the moving portion 53 and is movable in the X direction.

The moving mechanism 6 has a fixed portion 61, a pair of moving portions 63, 64, and a pair of mounting portions 65, 66. The fixing portion 61 is attached to the apparatus frame 1 a. The pair of moving portions 63 and 64 are respectively attached to rails provided on the fixed portion 61 and can independently move in the Y direction. The mounting portion 65 is mounted on a rail provided in the moving portion 63 and is movable in the Z direction. The mounting portion 66 is mounted on a rail provided in the moving portion 64 and is movable in the Z direction. That is, the pair of mounting portions 65, 66 are movable in the Y direction and the Z direction, respectively, with respect to the apparatus frame 1 a.

The support portion 7 is attached to a rotary shaft provided in the attachment portion 55 of the moving mechanism 5 and is rotatable about an axis parallel to the Z direction as a center line. That is, the support portion 7 is movable in the X direction and the Y direction, respectively, and is rotatable about an axis parallel to the Z direction as a center line. The support portion 7 supports the object 100. The object 100 is, for example, a wafer.

As shown in fig. 1 and 2, the laser processing head 10A is attached to an attachment portion 65 of the moving mechanism 6. The laser processing head 10A irradiates the object 100 supported by the support 7 with the laser light L1 in a state of facing the support 7 in the Z direction. The laser processing head 10B is attached to the attachment 66 of the moving mechanism 6. The laser processing head 10B irradiates the object 100 supported by the support 7 with the laser light L2 in a state of facing the support 7 in the Z direction.

The light source unit 8 has a pair of light sources 81, 82. The light source 81 outputs laser light L1. The laser light L1 is emitted from the emission portion 81a of the light source 81 and guided to the laser processing head 10A through the optical fiber 2. The light source 82 outputs laser light L2. The laser light L2 is emitted from the emission portion 82a of the light source 82 and guided to the laser processing head 10B through the other optical fiber 2.

The control unit 9 controls each unit (the support unit 7, the plurality of moving mechanisms 5 and 6, the pair of laser processing heads 10A and 10B, the light source unit 8, and the like) of the laser processing apparatus 1. The control unit 9 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 9, software (program) read into a memory or the like is executed by the processor, and reading and writing of data in the memory or the storage and communication by the communication device are controlled by the processor. Thereby, the control section 9 realizes various functions.

An example of the processing performed by the laser processing apparatus 1 configured as described above will be described. One example of this processing is an example in which a modified region is formed inside an object 100, which is a wafer, along a plurality of lines set in a lattice shape in order to cut the object 100 into a plurality of chips. The laser processing apparatus 1 may perform a peeling process of peeling off a part of the object 100.

First, the moving mechanism 5 moves the support 7 in the X direction and the Y direction, respectively, so that the support 7 supporting the object 100 faces the pair of laser processing heads 10A and 10B in the Z direction. Next, the moving mechanism 5 rotates the support 7 about an axis parallel to the Z direction as a center line so that a plurality of lines extending in one direction in the object 100 are along the X direction.

Next, the moving mechanism 6 moves the laser processing head 10A in the Y direction so that the condensed point (a part of the condensed region) of the laser light L1 is positioned on a line extending in one direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B in the Y direction so that the converging point of the laser light L2 is located on another line extending in one direction. Next, the moving mechanism 6 moves the laser processing head 10A in the Z direction so that the focal point of the laser light L1 is positioned inside the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B in the Z direction so that the converging point of the laser light L2 is positioned inside the object 100.

Next, the light source 81 outputs the laser beam L1, the laser machining head 10A irradiates the object 100 with the laser beam L1, the light source 82 outputs the laser beam L2, and the laser machining head 10B irradiates the object 100 with the laser beam L2. At the same time, the moving mechanism 5 moves the support 7 in the X direction so that the focal point of the laser light L1 relatively moves along one line extending in one direction and the focal point of the laser light L2 relatively moves along another line extending in one direction. In this way, the laser processing apparatus 1 forms a modified region in the object 100 along each of a plurality of lines extending in one direction in the object 100.

Next, the moving mechanism 5 rotates the support 7 about an axis parallel to the Z direction as a center line so that a plurality of lines extending in the other direction orthogonal to the one direction in the object 100 are along the X direction.

Next, the moving mechanism 6 moves the laser processing head 10A in the Y direction so that the converging point of the laser light L1 is positioned on a line extending in the other direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B in the Y direction so that the converging point of the laser light L2 is positioned on another line extending in the other direction. Next, the moving mechanism 6 moves the laser processing head 10A in the Z direction so that the focal point of the laser light L1 is positioned inside the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B in the Z direction so that the converging point of the laser light L2 is positioned inside the object 100.

Next, the light source 81 outputs the laser beam L1, the laser machining head 10A irradiates the object 100 with the laser beam L1, the light source 82 outputs the laser beam L2, and the laser machining head 10B irradiates the object 100 with the laser beam L2. At the same time, the moving mechanism 5 moves the support 7 in the X direction so that the focal point of the laser light L1 relatively moves along one line extending in the other direction and the focal point of the laser light L2 relatively moves along another line extending in the other direction. In this way, the laser processing apparatus 1 forms the modified region in the object 100 along each of the plurality of lines extending in the other direction orthogonal to the one direction in the object 100.

In the above-described processing example, the light source 81 outputs the laser light L1 that is transmissive to the object 100, for example, by a pulse oscillation method, and the light source 82 outputs the laser light L2 that is transmissive to the object 100, for example, by a pulse oscillation method. When such a laser beam is condensed inside the object 100, the laser beam is particularly absorbed in a portion corresponding to the condensing point of the laser beam, and a modified region is formed inside the object 100. The modified region is a region having a density, refractive index, mechanical strength, and other physical properties different from those of the surrounding unmodified region. Examples of the modified region include a melt-processed region, a crack region, an insulation breakdown region, and a refractive index change region.

When the object 100 is irradiated with the laser light output by the pulse oscillation method and the converging point of the laser light is relatively moved along a line set on the object 100, a plurality of modified spots are formed to be arranged in 1 line along the line. The 1 modified spots are formed by irradiation of 1 pulse of laser light. The 1-column modified region is a set of a plurality of modified light spots arranged in 1 column. The adjacent modified spots may be connected to each other or separated from each other depending on the relative movement speed of the converging point of the laser light with respect to the object 100 and the repetition frequency of the laser light. The shape of the set line is not limited to the lattice shape, and may be a ring shape, a straight line shape, a curved line shape, or a combination of at least any of these.

[ Structure of laser processing head ]

As shown in fig. 3 and 4, the laser processing head 10A includes a housing 11, an incident portion 12, an adjusting portion 13, and a light condensing portion 14.

The housing 11 has 1 st and 2 nd wall portions 21 and 22, 3 rd and 4 th wall portions 23 and 24, and 5 th and 6 th wall portions 25 and 26. The 1 st wall portion 21 and the 2 nd wall portion 22 are opposed to each other in the X direction. The 3 rd wall portion 23 and the 4 th wall portion 24 are opposed to each other in the Y direction. The 5 th wall portion 25 and the 6 th wall portion 26 are opposed to each other in the Z direction.

In the laser processing head 10A, the 1 st wall portion 21 is located on the opposite side of the fixing portion 61 of the moving mechanism 6, and the 2 nd wall portion 22 is located on the fixing portion 61 side. The 3 rd wall portion 23 is located on the mounting portion 65 side of the moving mechanism 6, and the 4 th wall portion 24 is located on the laser processing head 10B side opposite to the mounting portion 65 (see fig. 2). The 5 th wall portion 25 is located on the opposite side of the support portion 7, and the 6 th wall portion 26 is located on the support portion 7 side.

The housing 11 is configured such that the housing 11 is attached to the attachment portion 65 of the moving mechanism 6 in a state where the 3 rd wall portion 23 is disposed on the attachment portion 65 side. Specifically, the following is described. The mounting portion 65 has a bottom plate 65a and a mounting plate 65 b. The bottom plate 65a is attached to a rail provided in the moving unit 63 (see fig. 2). The mounting plate 65B is erected on the end of the base plate 65a on the laser processing head 10B side (see fig. 2). In a state where the 3 rd wall portion 23 is in contact with the attachment plate 65b, the bolt 28 is screwed to the attachment plate 65b via the base 27, whereby the housing 11 is attached to the attachment portion 65. The mounts 27 are provided on the 1 st wall portion 21 and the 2 nd wall portion 22, respectively. The housing 11 is detachable from the mounting portion 65.

Incident portion 12 is attached to 5 th wall portion 25. The incident unit 12 causes the laser beam L1 to enter the housing 11. The incident portion 12 is biased toward the 2 nd wall portion 22 (one wall portion side) in the X direction and biased toward the 4 th wall portion 24 in the Y direction.

The incident portion 12 is configured to be connectable to the connection end portion 2a of the optical fiber 2. A collimator lens for collimating the laser light L1 emitted from the emission end of the optical fiber is provided at the connection end 2a of the optical fiber 2, and no isolator for suppressing the return light is provided. The isolator is provided in the middle of the optical fiber on the light source 81 side of the connection end 2 a. This realizes the miniaturization of the connection end portion 2a and further the miniaturization of the incident portion 12. Further, an isolator may be provided at the connection end portion 2a of the optical fiber 2.

The adjustment portion 13 is disposed in the housing 11. The adjustment unit 13 adjusts the laser light L1 incident from the incident unit 12. Each of the components of the adjustment unit 13 is attached to an optical base 29 provided in the housing 11. The optical base 29 is attached to the housing 11 so as to partition the region inside the housing 11 into a region on the 3 rd wall portion 23 side and a region on the 4 th wall portion 24 side. The optical base 29 is integrated with the housing 11. Each configuration of the adjustment portion 13 is attached to the optical base 29 on the 4 th wall portion 24 side. The details of each configuration of the adjusting unit 13 will be described later.

The light-condensing portion 14 is disposed on the 6 th wall portion 26. Specifically, the light converging portion 14 is disposed on the 6 th wall portion 26 in a state of being inserted through a hole 26a (see fig. 5) formed in the 6 th wall portion 26. The light-condensing unit 14 emits the laser light L1 adjusted by the adjusting unit 13 to the outside of the housing 11 while condensing the laser light. The light collecting portion 14 is biased toward the 2 nd wall portion 22 (toward one wall portion) in the X direction and biased toward the 4 th wall portion 24 in the Y direction.

As shown in fig. 5, the adjusting section 13 has an attenuator 31, a beam expander 32, and a mirror 33. The attenuator 31, the beam expander 32, and the mirror 33 of the incident section 12 and the adjusting section 13 are arranged on a straight line (1 st straight line) a1 extending in the Z direction. The attenuator 31 and the beam expander 32 are disposed between the incident portion 12 and the mirror 33 on a straight line a 1. The attenuator 31 adjusts the output of the laser light L1 incident from the incident unit 12. The beam expander 32 expands the diameter of the laser light L1 whose output is adjusted by the attenuator 31. The mirror 33 reflects the laser light L1 whose diameter is expanded by the beam expander 32.

The adjustment section 13 also has a reflective spatial light modulator 34 and an imaging optical system 35. The reflective spatial light modulator 34, the imaging optical system 35, and the light condensing unit 14 of the adjustment unit 13 are arranged on a straight line (2 nd straight line) a2 extending in the Z direction. The reflective Spatial Light Modulator 34 is, for example, a Spatial Light Modulator (SLM) of a reflective Liquid Crystal (LCOS). The reflective spatial light modulator 34 modulates the laser light L1 reflected by the mirror 33. The reflective spatial light modulator 34 modulates the laser light L1 according to the displayed modulation pattern. A branching pattern for branching at least the laser light L1 into a plurality of beams is set and displayed on the reflective spatial light modulator 34. Thus, the laser light L1 incident on the reflective spatial light modulator 34 is branched into a plurality of laser lights in the reflective spatial light modulator 34 (details will be described later with reference to fig. 6). The imaging optical system 35 constitutes a bilateral telecentric optical system in which the reflection surface 34a of the reflection type spatial light modulator 34 and the entrance pupil surface 14a of the light condensing portion 14 are in an imaging relationship. The imaging optical system 35 is constituted by 3 or more lenses.

The straight line a1 and the straight line a2 are located on a plane perpendicular to the Y direction. The straight line a1 is located on the 2 nd wall portion 22 side (one wall portion side) with respect to the straight line a 2. In the laser processing head 10A, the laser light L1 enters the housing 11 from the entrance section 12, travels on the straight line a1, is sequentially reflected by the mirror 33 and the reflective spatial light modulator 34, travels on the straight line a2, and is emitted from the light collection section 14 to the outside of the housing 11. The order of arrangement of the attenuator 31 and the beam expander 32 may be reversed. The attenuator 31 may be disposed between the mirror 33 and the reflective spatial light modulator 34. The adjusting unit 13 may have another optical component (for example, a steering mirror disposed in front of the beam expander 32).

The laser processing head 10A further includes a dichroic mirror 15, a measurement section 16, a detection section 17, a drive section 18, and a circuit section 19.

The dichroic mirror 15 is disposed between the imaging optical system 35 and the light collecting unit 14 on the straight line a 2. That is, the dichroic mirror 15 is disposed between the adjustment unit 13 and the light collection unit 14 in the housing 11. The dichroic mirror 15 is attached to the optical base 29 on the 4 th wall portion 24 side. The dichroic mirror 15 transmits the laser light L1. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 is preferably of a cubic type or a 2-plate type arranged so as to have a twisted relationship, for example.

The measurement unit 16 is disposed on the 1 st wall portion 21 side (the side opposite to the one wall portion side) with respect to the adjustment unit 13 in the housing 11. The measuring unit 16 is attached to the optical base 29 on the 4 th wall portion 24 side. The measuring unit 16 outputs measuring light L10 for measuring the distance between the surface of the object 100 (for example, the surface on the side on which the laser light L1 is incident) and the light condensing unit 14, and detects the measuring light L10 reflected on the surface of the object 100 via the light condensing unit 14. That is, the measurement light L10 output from the measurement unit 16 is irradiated to the surface of the object 100 via the light-condensing unit 14, and the measurement light L10 reflected by the surface of the object 100 is detected by the measurement unit 16 via the light-condensing unit 14.

More specifically, the measurement light L10 output from the measurement unit 16 is reflected in sequence by the beam splitter 20 and the dichroic mirror 15 attached to the optical base 29 on the 4 th wall portion 24 side, and is emitted from the light collection unit 14 to the outside of the housing 11. The measurement light L10 reflected by the surface of the object 100 enters the housing 11 from the light collecting unit 14, is sequentially reflected by the dichroic mirror 15 and the beam splitter 20, enters the measurement unit 16, and is detected by the measurement unit 16.

The detection unit 17 is disposed on the 1 st wall portion 21 side (the side opposite to the one wall portion side) with respect to the adjustment unit 13 in the housing 11. The detection unit 17 is attached to the optical base 29 on the 4 th wall portion 24 side. The detector 17 outputs observation light L20 for observing the surface of the object 100 (for example, the surface on the side on which the laser light L1 is incident), and detects observation light L20 reflected by the surface of the object 100 via the light condenser 14. That is, the observation light L20 output from the detection unit 17 is irradiated to the surface of the object 100 via the light condensing unit 14, and the observation light L20 reflected by the surface of the object 100 is detected by the detection unit 17 via the light condensing unit 14. The detection unit 17 is, for example, a camera that detects (captures) the reflected observation light L20.

More specifically, the observation light L20 output from the detection unit 17 passes through the beam splitter 20, is reflected by the dichroic mirror 15, and is emitted from the light collection unit 14 to the outside of the housing 11. The observation light L20 reflected by the surface of the object 100 enters the housing 11 from the light collecting unit 14, is reflected by the dichroic mirror 15, passes through the beam splitter 20, enters the detection unit 17, and is detected by the detection unit 17. The laser light L1, the measurement light L10, and the observation light L20 have different wavelengths (at least their center wavelengths are shifted from each other).

The detection unit 17 detects a part of the laser beam L1 reflected by the surface of the object 100 (details will be described later). The part of the laser light L1 reflected on the surface of the object 100 is the laser light L1 that is slightly reflected toward the detector 17 by the dichroic mirror 15, among the laser light L1 reflected on the surface of the object 100.

The driving portion 18 is attached to the optical base 29 on the 4 th wall portion 24 side. The driving unit 18 moves the condensing unit 14 disposed on the 6 th wall 26 in the Z direction by the driving force of the piezoelectric element, for example.

The circuit portion 19 is disposed on the 3 rd wall portion 23 side with respect to the optical base 29 in the housing 11. That is, the circuit portion 19 is disposed on the 3 rd wall portion 23 side with respect to the adjusting portion 13, the measuring portion 16, and the detecting portion 17 in the housing 11. The circuit portion 19 is, for example, a plurality of circuit boards. The circuit unit 19 processes the signal output from the measurement unit 16 and the signal input to the reflective spatial light modulator 34. The circuit unit 19 controls the drive unit 18 based on the signal output from the measurement unit 16. For example, the circuit unit 19 controls the driving unit 18 so as to maintain the distance between the surface of the object 100 and the light converging unit 14 constant (that is, so as to maintain the distance between the surface of the object 100 and the light converging point of the laser light L1 constant) based on the signal output from the measurement unit 16. The housing 11 is provided with a connector (not shown) to which wiring for electrically connecting the circuit unit 19 and the control unit 9 (see fig. 1) is connected.

The laser processing head 10B includes a housing 11, an incident portion 12, an adjusting portion 13, a condensing portion 14, a dichroic mirror 15, a measuring portion 16, a detecting portion 17, a driving portion 18, and a circuit portion 19, similarly to the laser processing head 10A. However, as shown in fig. 2, the respective structures of the laser processing head 10B are arranged in a plane-symmetric relationship with the respective structures of the laser processing head 10A with respect to a virtual plane passing through a midpoint between the pair of mounting portions 65, 66 and perpendicular to the Y direction.

For example, the housing (1 st housing) 11 of the laser processing head 10A is attached to the attachment portion 65 such that the 4 th wall portion 24 is located on the laser processing head 10B side with respect to the 3 rd wall portion 23 and the 6 th wall portion 26 is located on the support portion 7 side with respect to the 5 th wall portion 25. On the other hand, the housing (2 nd housing) 11 of the laser processing head 10B is attached to the attachment portion 66 such that the 4 th wall portion 24 is located on the laser processing head 10A side with respect to the 3 rd wall portion 23 and the 6 th wall portion 26 is located on the support portion 7 side with respect to the 5 th wall portion 25.

The housing 11 of the laser processing head 10B is configured such that the housing 11 is attached to the attachment 66 in a state where the 3 rd wall portion 23 is disposed on the attachment 66 side. Specifically, the following is described. The mounting portion 66 has a bottom plate 66a and a mounting plate 66 b. The bottom plate 66a is attached to a rail provided in the moving portion 63. The attachment plate 66b is provided upright on the end of the base plate 66a on the laser processing head 10A side. The housing 11 of the laser processing head 10B is attached to the attachment portion 66 in a state where the 3 rd wall portion 23 is in contact with the attachment plate 66B. The housing 11 of the laser processing head 10B is detachable from the mounting portion 66.

[ branching of laser beam ]

The branching of the laser beam for the purpose of cutting, peeling, and the like of the object 100 will be described below with reference to fig. 6 to 8. As described above, the laser light L1 branches according to the branching pattern set and displayed in the reflective spatial light modulator 34.

Fig. 6 is a diagram illustrating a plurality of modified spots SA in the case where the laser light L1 is branched into 4. In the example shown in fig. 6, the laser light L1 is branched so that a plurality of (4) modified spots SA are formed in the object 100, the modified spots SA being aligned in a line along an oblique direction C2 that is oblique to a direction orthogonal to the machining direction C1. The branching of the laser light L1 is realized by a branching pattern (modulation pattern) set and displayed in the reflective spatial light modulator 34 (see fig. 5).

In the illustrated example, the laser light L1 is branched into 4 beams, and 4 modified spots SA are formed. In the adjacent pair of modified spots SA out of the 4 modified spots SA after branching, the interval in the processing direction C1 is the branching pitch BPx, and the interval in the direction orthogonal to the processing direction C1 is the branching pitch BPy. The interval in the machining direction C1 between the pair of modified spots SA formed by irradiation of the continuous 2-pulse laser light L1 is the pulse pitch PP. The angle between the machining proceeding direction C1 and the oblique direction C2 is a branch angle α.

Fig. 7 is a setting screen of the GUI111 for realizing branching of the laser beam L1 as shown in fig. 6. The GUI111 functions as an input unit that receives an input from a user. The setting screen of the GUI111 shown in fig. 7 includes: a processing condition selection button 211 for selecting a processing condition; a branch number column 212 for inputting or selecting the branch number of the laser light L1; an index column 213 for inputting an index as a distance moved to the next processing line after laser processing along 1 processing line; an impression map 214 for inputting or displaying the number of branches and index; a processing Z-height column 215 for inputting the position of the modified spot SA in the Z direction; a processing speed column 216 for inputting a processing speed; and a condition switching method button 217 for selecting a method of switching the processing conditions.

The machining condition selection button 211 enables selection of a specific machining condition from a plurality of options. According to the index column 213, when the number of branches is 1, the laser processing head 10A is automatically moved in the index direction by the input value. When the number of branches is greater than 1, the laser processing head 10A is automatically moved in the index direction by an index amount based on the following calculation formula.

Index (number of branches) × index input value

The icon 214 includes a display unit 214a for inputting an index input value and an output input field 214b for inputting the output of each modified spot SA.

Fig. 8 is a diagram showing an example of the administrator mode of the setting screen of the GUI 111. The setting screen shown in fig. 8 includes: a branch direction selection button 221 for selecting the branch direction of the laser light L1; a branch number column 222 for inputting or selecting the branch number of the laser light L1; a branch pitch input field 223 for inputting the branch pitch BPx; a branch pitch row number input field 224 for inputting the row number of the branch pitch BPx; a branch pitch input field 225 for inputting the branch pitch BPy; an index bar 226 for inputting an index; an optical axis impression map 227 based on the number of branches; an outgoing/returning selection button 228 for selecting whether the scanning direction of the laser light L1 is one direction (outgoing) or the other direction (returning); and a balance adjustment start button 229 that automatically adjusts the balance of the various values.

[ Branch pattern correction processing ]

In the laser processing apparatus 1 of the present embodiment, at the early stage of processing (processing) for forming a modified region in the object 100, a1 st branching pattern corresponding to an output ratio (output target value) of each laser light after branching is generated based on a predetermined calculation formula (calculation algorithm), the laser light is emitted to the object 100 in a state where the 1 st branching pattern is displayed on the reflective spatial light modulator 34, reflected light of each laser light after branching using the 1 st branching pattern is detected, an output actual measurement value of each laser light after branching is derived based on the detection result, and a balance parameter (correction parameter) related to generation of the 2 nd branching pattern for bringing the output actual measurement value close to a desired output ratio (output target value) is generated. Then, at the time of processing, in the laser processing apparatus 1, the 2 nd branch pattern is generated based on the calculation formula after correction by the balance parameter correction calculation formula, and the 2 nd branch pattern is set and displayed on the reflective spatial light modulator 34 to be used for processing.

As described above, in the laser processing apparatus 1 of the present embodiment, the 1 st branching pattern generated based on the predetermined calculation formula is not directly used for the processing, but the actual output measurement value of each laser beam after branching in the case where the 1 st branching pattern is used is derived before the processing, the balance parameter for generating the 2 nd branching pattern that reduces the error between the assumed output ratio and the actual output measurement value is generated, and the calculation formula is corrected by using the balance parameter at the time of the processing, and the 2 nd branching pattern generated based on the calculation formula after correction is used. This makes it possible to appropriately adjust the output of the branched light to a desired value (output ratio), thereby improving the processing quality.

The error (error between the assumed output ratio and the actually measured output value) before correction occurs due to, for example, the influence of the optical characteristics of the spatial light modulator itself, the optical characteristics such as the difference in the transmission regions of the respective branched lights in the lens, or the individual difference of the optical elements.

Fig. 9 is a table showing the error of the actual measurement value of each output ratio with respect to the design value (ideal output ratio) in the 2-point branching. The left diagram of fig. 9 shows an error in the case where the above-described 1 st branch pattern is used without performing the correction based on the balance parameter. As shown in the left diagram of fig. 9, when the correction based on the balance parameter is not performed, for example, when the design value of the output ratio of the 2-point branch is 20:80, the actual measurement value is 9:91 (error 11%), when the design value is 30:70, the actual measurement value is 21:79 (error 9%), when the design value is 40:60, the actual measurement value is 35:65 (error 5%), when the design value is 50:50, the actual measurement value is 51:49 (error 1%), when the design value is 60:40, the actual measurement value is 65:35 (error 5%), and particularly when the difference of the output of the 2-point branch is large, the error becomes large.

The laser processing apparatus 1 generates a balance parameter for bringing the measured output value close to the design value (ideal output ratio) based on the error information shown in the left diagram of fig. 9. The balance parameter corrects the calculation formula for generating the branch pattern, and the 2 nd branch pattern (branch pattern in which the output measured value is close to the design value) can be generated based on the corrected calculation formula. The right diagram of fig. 9 shows an error in the case of using the 2 nd branch pattern generated by performing the correction based on the balance parameter. In the example shown in the right diagram of fig. 9, by applying the balance parameter, that is, the 2 nd branch parameter generated by the balance parameter correction calculation formula, the error in each output ratio becomes small, and the maximum error becomes small to 3%. Fig. 9 shows an error in the case where the 1 st branching pattern is set to a condition of no vertical branching and the condition of no vertical branching is also set in the processing to which the 2 nd branching pattern is applied.

The effect of generating and applying the balance parameter is not limited to the 2-point branch, and the number of other branches is the same. Fig. 10 is a table showing the error of the actual measurement value with respect to the design value in each output ratio at the 3-point branching. Fig. 11 is a table showing the error of the actual measurement value with respect to the design value in each output ratio at the 4-point branching. As shown in the left diagram of fig. 10, when the correction based on the balance parameter is not performed, the maximum error of each output ratio at the time of branching at 3 points is 8%, but as shown in the right diagram of fig. 10, the maximum error of each output ratio at the time of branching at 3 points is reduced to 3% by applying the balance parameter. In addition, as shown in the left diagram of fig. 11, when the correction based on the balance parameter is not performed, the maximum error of each output ratio at the time of the 4-point branching is 9%, but as shown in the right diagram of fig. 11, the maximum error of each output ratio at the time of the 4-point branching is reduced to 3% by applying the balance parameter.

The laser processing apparatus 1 may generate a1 st branching pattern for performing vertical branching in which the laser beam is branched to different positions in the Z direction (vertical direction) in the thickness direction of the object 100. Fig. 12 is a diagram illustrating a vertical branching mode. Fig. 12(a) shows the respective laser beams in the case of 3-point branching without vertical branching, and fig. 12(b) shows the respective laser beams in the case of 3-point branching with vertical branching. In fig. 12(a) and 12(b), the horizontal axis represents the machining direction, and the vertical axis represents the Z direction (vertical direction). As shown in fig. 12(a), the branched laser beams are irradiated at the same height in the Z direction in a state where no vertical branch is present. On the other hand, as shown in fig. 12(b), in a state where there is a vertical branch, the branched laser beams are irradiated to mutually different heights in the Z direction. In addition, "the vertical branch VD 0" in fig. 12(a) means no vertical branch, and "the vertical branch VD 16" in fig. 12(b) means that there is a vertical branch and the branch pitch in the Z direction is 16 μ.

Fig. 13 is a table showing the error of the actual measurement value with respect to the design value in each output ratio at the time of 3-point branching when the balance parameter acquired without vertical branching is applied to the machining with vertical branching (VD 16). In the left diagram of fig. 13, an error in the case of using the 1 st branch pattern without vertical branches is shown. The right diagram of fig. 13 shows an error in the case where machining is performed with a vertical branch (VD16) using the 2 nd branch parameter generated by performing correction of the balance parameter based on the information of the error in the case where there is no vertical branch as shown in the left diagram of fig. 13. As described above, when there is no vertical branching in both the processing using the 1 st branching pattern and the processing using the 2 nd branching pattern, the maximum error can be reduced to 3% at the time of branching at 3 points as shown in the right diagram of fig. 10. On the other hand, when the balance parameter is generated by the 1 st branch pattern without vertical branches and the machining with vertical branches (VD16) is performed by using the 2 nd branch pattern generated by performing the correction based on the balance parameter, the maximum error becomes 4% as shown in the right diagram of fig. 13. In this way, when the conditions for generating the balance parameters and for processing the vertical branches are different from each other, it is considered that the error of the measured value from the design value cannot be sufficiently reduced even if the balance parameters are applied.

Fig. 14 is a table showing the error of the actual measurement value with respect to the design value in each output ratio at the time of 3-point branching when the balance parameter acquired when the vertical branching (VD16) is applied to the machining with the vertical branching (VD 16). Both the processing using the 1 st branching pattern and the processing using the 2 nd branching pattern are set to have vertical branching (VD16), and the maximum error can be reduced to 3% as shown in the right diagram of fig. 14. In this way, by sharing the conditions of the balance parameter generation and the vertical branching of the processing, it is possible to sufficiently reduce the error of the actual measurement value with respect to the design value.

Fig. 15 is a table showing the relationship between the vertical branch amount and the maximum error. The "vertical branch amount" in fig. 15 indicates the vertical branch amount during the processing. The "maximum error" in fig. 15 indicates the maximum error of a certain output ratio when the vertical branch machining indicated by the "vertical branch amount" is performed by applying the balance parameter generated by the 1 st branch pattern based on the VD 16. As shown in fig. 16, when the balance parameter generated by the 1 st branching pattern of VD16 is applied, the maximum error becomes the minimum (0.8%) when branching processing of VD16 is performed. As shown in fig. 16, when the branching processing of VD2 is performed by applying the balance parameter generated by the 1 st branching pattern of VD16, the maximum error is relatively small, and is 1.4%. In this way, even if the conditions of the vertical branching of the balance parameter generation and the machining do not coincide with each other, in the case where the vertical branching machining is performed, the error can be reduced by using the balance parameter generated under the condition of the vertical branching.

The laser processing apparatus 1 may generate a plurality of types of 1 st branching patterns in which combinations of output ratios (output target values) of the branched laser beams are different from each other, and generate a common balance parameter relating to the plurality of types of 1 st branching patterns. Here, for example, if the common balance parameter relating to each output ratio is generated so that the error of the actual measurement value with respect to the design value in the region a (the region surrounded by the solid line quadrangle) shown in the left diagram of fig. 16 becomes small (e.g., minimized), as shown in the left diagram of fig. 16, the error in the region B (the region surrounded by the one-dot chain line quadrangle) and the region C (the region surrounded by the dotted line quadrangle) different from the region a becomes large at 3% to 6%, although the error in the region a becomes small at 1% or less. In this way, in the balance parameter generated so as to reduce the error in a certain region, the error in a region distant from the certain region cannot be sufficiently reduced.

Therefore, the laser processing apparatus 1 may perform grouping according to the degree of approximation of the output ratio (output target value) as the branch parameter, and generate the common balance parameter in units of groups. That is, the laser processing apparatus 1 may generate the common balance parameter in units of groups (regions) having similar output ratios. The right diagram of fig. 16 shows the error in the 3-point branch when 1 common balance parameter is generated for each region A, B, C. As shown in the right diagram of fig. 16, if a common balance parameter is generated for each region A, B, C, the error between the design value and the actual measurement value can be reduced to about 1% in all output ratios. In this way, by switching the balance parameters in accordance with the output ratio used during machining, it is possible to reduce the error of the actual measurement value with respect to the design value.

The function of the control unit 9 for realizing the branch pattern correction process will be described in detail below.

The control unit 9 is configured to execute the following processing: a1 st process of generating a1 st branching pattern corresponding to an output ratio (output target value) of each laser beam after branching as a branching pattern for branching the laser beam into a plurality of beams based on a predetermined calculation formula (calculation algorithm), setting the generated 1 st branching pattern, and displaying the set 1 st branching pattern on the reflective spatial light modulator 34; a2 nd process of controlling the light source unit 8 so that laser light is emitted in a state where the reflective spatial light modulator 34 displays the 1 st branch pattern; a 3 rd process of controlling the detection unit 17 to detect the reflected light of each laser beam after branching by the 1 st branching pattern; a 4 th process of deriving an output actual measurement value of each laser beam after branching based on a detection result of the detection unit 17, and generating a correction parameter for correcting the calculation formula, that is, a balance parameter (correction parameter) for generating a2 nd branching pattern as a branching pattern for bringing the output actual measurement value close to a desired output ratio (output target value); and a 5 th process of generating a2 nd branch pattern based on the corrected calculation formula by the balance parameter correction calculation formula, setting the generated 2 nd branch pattern and displaying the set pattern on the reflective spatial light modulator 34 for use in the processing.

In the 1 st process, the control unit 9 determines an output ratio based on information received on the setting screen (see fig. 7 and 8) of the GUI111, and sets the 1 st branching pattern corresponding to the determined output ratio to the reflective spatial light modulator 34. The control unit 9 generates the 1 st branch pattern corresponding to the output ratio based on a calculation formula (calculation algorithm) stored in advance. The control unit 9 may generate a plurality of types of 1 st branching patterns having different combinations of the output ratios of the branched laser beams. The control unit 9 may generate a1 st branching pattern for performing vertical branching so as to branch the laser beam to different positions in the Z direction (vertical direction) in the thickness direction of the object 100.

In the 2 nd process, the control unit 9 controls the light source unit 8, for example, so that the laser light is irradiated at an output (below the modification threshold) at which no modified region is formed in the object 100 in a state where the 1 st branch pattern is displayed on the reflective spatial light modulator 34. Further, the branched laser beam may be irradiated to an object (object for correction) different from the object 100 subjected to the laser processing after the branching pattern correction processing.

In the 3 rd process, the control unit 9 controls the detection unit 17 so that the reflected light of each of the branched laser beams on the object 100 can be detected (imaged) at least while each of the branched laser beams is irradiated on the object 100. The control unit 9 acquires the image captured by the detection unit 17 from the detection unit 17.

In the 4 th process, the control unit 9 estimates (derives) actual output measurement values of the respective laser beams, for example, based on the brightness of each point corresponding to the respective branched laser beams in the imaging data acquired by the detection unit 17. The control unit 9 generates, as a correction parameter of the correction calculation formula, a balance parameter for generating the 2 nd branch pattern in which the output measured value is brought close to the desired output ratio. When a plurality of types of 1 st branching patterns are generated, the control unit 9 generates a common correction parameter for at least 21 st branching patterns included in the plurality of types of 1 st branching patterns. The control unit 9 may generate a common correction parameter for all the 1 st branch patterns, or may group a plurality of types of the 1 st branch patterns according to the degree of approximation of the branch parameter, and generate a common balance parameter for each group. The branch parameter includes, for example, the number of branches, an output ratio (output target value), a vertical branch amount, an individual aberration correction amount, and the like. In the example shown in fig. 16, the control unit 9 groups the output ratios as the branch parameters into groups, and generates the balance parameters in units of each of the groups of the area a, the area B, and the area C.

In the 5 th process, the control unit 9 executes a process of generating the 2 nd branch pattern based on the corrected calculation formula by using the balance parameter correction calculation formula, and a process of setting and displaying the 2 nd branch pattern on the reflective spatial light modulator 34 at the time of the machining process. The control unit 9 may acquire information indicating a branching parameter in the machining process, and correct the calculation formula based on the balance parameter of the group corresponding to the branching parameter. Fig. 17 and 18 are diagrams for explaining the operation of the balance parameter corresponding to the branch parameter. The control unit 9 may acquire information indicating the number of branches as information indicating a branch parameter in the machining process, based on information received on a setting screen (see fig. 7 and 8) of the GUI111, specify a balance parameter corresponding to the number of branches, and correct the calculation formula based on the specified balance parameter, as shown in fig. 17. Fig. 17 shows that the balance parameter for 2-point branching is reflected in the calculation formula when the number of branches is 2, the balance parameter for 3-point branching is reflected in the calculation formula when the number of branches is 3, and the balance parameter for 4-point branching is reflected in the calculation formula when the number of branches is 4.

The control unit 9 may acquire information indicating the output ratio as information indicating a branching parameter in the machining process based on information received on the setting screen (see fig. 7 and 8) of the GUI111, specify a balance parameter corresponding to the output ratio, and correct the calculation formula based on the specified balance parameter. For example, it is assumed that balance parameters are generated for each of 3 regions (region a, region B, and region C) corresponding to the output ratio as shown in fig. 16. In this case, as shown in fig. 18, for example, the control unit 9 causes the balance parameter of the region a (balance parameter list a shown in fig. 18) to be reflected in the calculation formula when the output ratio included in the region a is set, and causes the balance parameter of the region B (balance parameter list B shown in fig. 18) to be reflected in the calculation formula when the output ratio included in the region B is set.

Next, the generation process of the branch pattern to which the balance parameter is applied will be described with reference to fig. 19 and 20. Fig. 19 and 20 are flowcharts explaining the generation process of the branch pattern to which the balance parameter is applied. Fig. 19 shows an example of using 1 balance parameter, and fig. 20 shows an example of switching between a plurality of balance parameters.

As shown in fig. 19, first, the 1 st branching pattern is derived based on the information (design value) received on the setting screen of the GUI111, and the 1 st branching pattern is set and displayed on the reflective spatial light modulator 34 (step S1: 1 st step).

Then, the laser beam L1 is emitted to the reflective spatial light modulator 34 showing the 1 st branch pattern, and the object 100 is irradiated with the laser beam branched into a plurality of beams according to the 1 st branch pattern to start laser irradiation (step S2: 2 nd step).

Then, the detection unit 17 detects (images) the reflected light of the branched light from the object 100 (step S3: step 3).

Next, an actual output measurement value of each laser beam after branching is derived based on the imaging data (detection result of reflected light), and a balance parameter is generated based on an error between the actual output measurement value and a desired output ratio (output target value, design value) (step S4: step 4).

Finally, the 2 nd branch pattern is generated based on the corrected calculation formula by the balance parameter correction calculation formula, and the generated 2 nd branch pattern is set and displayed on the reflective spatial light modulator 34 to be used in the processing (step S5: step 5).

Next, an example in which a plurality of balance parameters are used for handover will be described with reference to fig. 20. As shown in fig. 20, the processing of steps S11 to S14 is the same as the processing of steps S1 to S4 of fig. 19. However, in step S14, the plurality of types of 1 st branch patterns are grouped according to the degree of approximation of the branch parameter, and the balance parameter is generated for each group.

Then, information (processing conditions) indicating the branching parameters in the processing is acquired, and the balance parameters are switched based on the processing conditions (for example, output ratio) (step S15). That is, a balance parameter that meets the processing conditions is selected from the plurality of balance parameters.

Finally, the calculation formula is corrected according to the selected balance parameter, the 2 nd branch pattern is generated based on the corrected calculation formula, and the generated 2 nd branch pattern is set and displayed on the reflective spatial light modulator 34 for the processing.

Next, the operational effects of the laser processing apparatus 1 of the present embodiment will be described.

The laser processing apparatus 1 of the present embodiment is a laser processing apparatus for forming a modified region in an object 100 by irradiating the object 100 with laser light, and includes: a light source unit 8 that emits laser light; a reflective spatial light modulator 34 that modulates laser light emitted from the light source unit 8; a detection unit 17 for detecting the reflected light of the laser beam from the object 100; and a control unit 9, the control unit 9 being configured to execute: a1 st process of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation formula, and setting and displaying the generated 1 st branching pattern on the reflective spatial light modulator 34; a2 nd process of controlling the light source unit 8 so that laser light is emitted in a state where the reflective spatial light modulator 34 displays the 1 st branch pattern; a 3 rd process of controlling the detection unit 17 to detect the reflected light of each laser beam after branching by the 1 st branching pattern; a 4 th process of deriving an actual output measurement value of each laser beam after branching based on a detection result of the detection unit 17, and generating a correction parameter for correcting the calculation formula, that is, a balance parameter for generating a2 nd branching pattern as a branching pattern for bringing the actual output measurement value close to the target output value; and a 5 th process of correcting the calculation formula according to the balance parameter, generating a2 nd branch pattern based on the corrected calculation formula, and setting and displaying the generated 2 nd branch pattern on the reflective spatial light modulator 34 for use in the processing.

In the laser processing apparatus 1 of the present embodiment, the laser beam is emitted in a state where the 1 st branch pattern generated based on the output target value of each laser beam after branching is displayed on the reflective spatial light modulator 34, the reflected light from the object 100 is detected, and the output actual measurement value of each laser beam is derived based on the detection result. Then, in the laser processing apparatus 1, the balance parameter for generating the 2 nd branch pattern for bringing the output actual measurement value close to the output target value is generated, the 2 nd branch pattern is generated by the calculation formula corrected by the balance parameter, and the 2 nd branch pattern is displayed on the reflective spatial light modulator 34 to be used for the processing. According to such a configuration, the balance parameter for generating the 2 nd branch pattern for bringing the output actual measurement value estimated with high accuracy based on the actually detected reflected light close to the output target value is generated. Therefore, at the time of the machining process, the calculation formula is corrected by the balance parameter, and the 2 nd branching pattern capable of bringing the output of the branching light closer to the output target value than the 1 st branching parameter is generated, whereby the output of the branching light can be appropriately adjusted to a desired value. As described above, according to the laser processing apparatus 1 of the present embodiment, the output of the branched light can be adjusted to a desired value, and the processing quality can be improved.

The control unit 9 may generate a plurality of types of 1 st branching patterns having different combinations of the output target values of the laser beams after branching in the 1 st processing, and generate a common balance parameter for at least 21 st branching patterns included in the plurality of types of 1 st branching patterns in the 4 th processing. In this way, by generating a common balance parameter for a plurality of 1 st branch patterns having different conditions for outputting the target value, it is possible to generate the 2 nd branch patterns each unique using the same balance parameter, and it is possible to facilitate the generation processing and management of the balance parameter compared to the case where the balance parameter is generated for each 1 st branch pattern.

In the 4 th process, the control unit 9 may group the plurality of types of 1 st branch patterns according to the approximation degree of the balance parameter, and generate the common balance parameter for each group. For example, even when 1 balance parameter common to all the 1 st branching patterns is generated, or when the 1 st branching patterns and the like having greatly different branching parameters are included, the accuracy of all the 2 nd branching patterns (the accuracy of bringing the output of the branching light close to the output target value) cannot be sufficiently improved by correcting the calculation formula using the generated common balance parameter. In this regard, by generating a common balance parameter for each group having a similar branch parameter, that is, by generating another balance parameter between groups having dissimilar branch parameters, the accuracy of the 2 nd branch pattern (the accuracy of bringing the output of the branch light closer to the output target value) can be ensured.

The control unit 9 may perform grouping according to the degree of approximation of the output target value as the branch parameter in the 4 th process. Thus, since the common balance parameter is generated in units of groups whose output target values are approximate, the accuracy of the 2 nd branch pattern (the accuracy of bringing the output of the branch light close to the output target value) can be ensured.

The control unit 9 may acquire information indicating a branch parameter during the machining process in the 5 th process, and correct the calculation formula based on the balance parameter of the group corresponding to the branch parameter. Thus, the 2 nd branch pattern generated from the calculation formula after the balance parameter correction suitable for the branch parameter in the machining process can be displayed to perform the machining process, and the machining quality can be improved.

The control unit 9 may generate a1 st branching pattern for branching the laser beam to different positions in the vertical direction, which is the thickness direction of the object 100, in the 1 st process. In actual processing, there are cases where the laser light branches off at different positions in the vertical direction (vertical branching), and by generating the 1 st branching pattern relating to this vertical branching, it is possible to generate a balance parameter relating to the generation of the 2 nd branching pattern that can appropriately bring the output of the branched light in the case of vertical branching close to the output target value.

The embodiments have been described above, but the present invention is not limited to the above embodiments. For example, the method of generating the balance parameter (correction parameter) and detecting the reflected light from the object by the detection unit as a method of measuring the output of each laser beam after branching has been described, but the method is not limited to this. Specifically, the output of each laser after branching, which is involved in the generation of the balance parameter, may be measured by a power meter. Hereinafter, a mode using a power meter will be described with reference to fig. 21 and 22.

Fig. 21 is a schematic configuration diagram of a laser processing apparatus 500 according to a modification. As shown in fig. 21, the laser processing apparatus 500 includes a laser light source 402, a reflective spatial light modulator 403, a 4f optical system 441, a light shielding plate 420, and a condensing optical system 404 in a housing 431. The laser processing apparatus 500 is an apparatus for forming a modified region in an object by condensing a laser beam L on the object. Here, for example, a scenario is assumed in which balance parameters are generated at the time of manufacturing or adjusting the laser processing apparatus 500, and an object to be processed is not provided on a table (not shown). Then, the power meter 700 for measuring the intensity of the laser beam is disposed below the condensing optical system 404 (for example, placed on a stage (not shown)), and a balance parameter is generated based on the output measurement result of the laser beam by the power meter 700 (details will be described later).

The laser light source 402 is fixed to a ceiling 436 of the housing 431 with screws or the like so as to emit the laser light L in the horizontal direction. The reflective spatial light modulator 403 modulates the laser light L emitted from the laser light source 402, modulates the laser light L incident from the horizontal direction, and reflects the laser light L obliquely upward with respect to the horizontal direction.

The 4f optical system 441 adjusts the wavefront shape of the laser light L modulated by the reflective spatial light modulator 403, and includes a1 st lens 441a and a2 nd lens 441 b. The 1 st lens 441a and the 2 nd lens 441b are arranged on the optical path between the reflective spatial light modulator 403 and the condensing optical system 404 as follows: the distance of the optical path between the reflective spatial light modulator 403 and the 1 st lens 441a is the 1 st focal length of the 1 st lens 441a, the distance of the optical path between the condensing optical system 404 and the 2 nd lens 441b is the 2 nd focal length of the 2 nd lens 441b, the distance of the optical path between the 1 st lens 441a and the 2 nd lens 441b is the sum of the 1 st focal length and the 2 nd focal length, and the 1 st lens 441a and the 2 nd lens 441b are both-side telecentric optical systems. According to the 4f optical system 441, it is possible to suppress the wavefront shape change and the increase of aberration of the laser light L modulated by the reflective spatial light modulator 403 due to spatial propagation.

The light shielding plate 420 is an aperture member having an opening 420a through which the 1 st processing light and the 2 nd processing light described below pass. The light blocking plate 420 is disposed on a fourier plane (i.e., a plane including the confocal point O) between the 1 st lens 441a and the 2 nd lens 441 b. As will be described later, the power meter 700 measures the output of the branched light while changing the range of the laser light L blocked by the light blocking plate 420. The position where the mask 420 cuts the laser light L may not necessarily be the position where the focal point is the smallest, and may be in the vicinity of the fourier plane.

The condensing optical system 404 condenses the laser light L emitted from the laser light source 402 and modulated by the reflective spatial light modulator 403 on the power meter 700. The condensing optical system 404 includes a plurality of lenses, and is provided on a bottom plate 433 of a housing 431 via a driving unit 432 including a piezoelectric element or the like.

In the laser processing apparatus 500 configured as described above, the laser light L emitted from the laser light source 402 travels horizontally in the housing 431, and then is reflected downward by the mirror 405a, and the light intensity is adjusted by the attenuator 407. Then, the laser beam is reflected in the horizontal direction by the mirror 405b, and the intensity distribution of the laser beam L is homogenized by the beam homogenizer 460 and enters the reflective spatial light modulator 403.

The laser light L incident on the reflective spatial light modulator 403 is transmitted through a branch pattern, which is a modulation pattern displayed on the liquid crystal layer, and is modulated (branched) in accordance with the modulation pattern. Such a modulation pattern (branching pattern) is generated by the control unit 450 based on the output target value of each laser beam after branching. Each of the branched laser beams is then reflected upward by the mirror 406a, changed in polarization direction by the λ/2 wavelength plate 428, reflected in the horizontal direction by the mirror 406b, and incident on the 4f optical system 441.

4f, the wavefront shape is adjusted so that the laser light L incident on the optical system 441 is incident on the condensing optical system 404 as parallel light. Specifically, each of the branched laser beams L is converged through the 1 st lens 441a, reflected downward by the mirror 419, passed through the confocal point O to be diffused, and converged into parallel light again through the 2 nd lens 441 b. Then, the laser light L is sequentially transmitted through the dichroic mirrors 410 and 438, enters the condensing optical system 404, and is condensed by the condensing optical system 404 on the power meter 700.

In addition, the laser processing apparatus 500 may be provided with a surface observation unit 411 for observing a laser light entrance surface with respect to the object and an AF (Auto Focus) unit 412 for finely adjusting a distance between the condensing optical system 404 and the object in the housing 431. The surface observation unit 411 has an observation light source 411a and a detector 411 b.

The laser processing apparatus 500 includes a control unit 450 configured by a CPU, a ROM, a RAM, and the like as a means for controlling the laser processing apparatus 500. The control unit 450 controls the laser light source 402 to adjust the output, pulse width, and the like of the laser light L emitted from the laser light source 402. The controller 450 controls the positions of the housing 431 and the table (not shown) and the driving of the driving unit 432.

The control unit 450 applies a predetermined voltage to each pixel electrode in the reflective spatial light modulator 403 to cause the liquid crystal layer to display a predetermined modulation pattern (branching pattern), thereby causing the laser light L to be modulated (branched) as desired in the reflective spatial light modulator 403. Here, the modulation pattern displayed in the liquid crystal layer is generated in advance and stored in the control unit 450. The modulation pattern includes an individual difference correction pattern for correcting an individual difference (for example, distortion generated in the liquid crystal layer of the reflective spatial light modulator 403) generated in the laser processing apparatus 500, a spherical aberration correction pattern for correcting spherical aberration, and the like.

The laser processing method performed by the laser processing apparatus 500 configured as described above includes: a1 st step of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation algorithm, setting the generated 1 st branching pattern, and displaying the set 1 st branching pattern on the reflective spatial light modulator 403; a2 nd step of emitting laser light to the reflective spatial light modulator 403 on which the 1 st branching pattern is displayed, measuring the laser light branched into a plurality of laser light by the 1 st branching pattern with the power meter 700, and deriving actual output measurement values of the branched laser light; and a 3 rd step of generating and outputting a correction parameter for correcting the calculation algorithm, that is, a balance parameter for generating the 2 nd branch pattern as a branch pattern for bringing the output measured value close to the output target value. In the step2, a light-blocking output measurement process is performed in which a part of each branched laser beam is blocked by the light blocking plate 420 and an output is measured by the power meter 700, and in this light-blocking output measurement process, an output is measured by the power meter 700 while changing the range of the laser beam blocked by the light blocking plate 420.

Fig. 22 is a diagram illustrating the output derivation of each laser beam after branching by the power meter 700. Fig. 22(a) shows the branched light from the reflective spatial light modulator 403 reaching the power meter 700. Fig. 22(b) shows the position of the light shielding plate 420 provided on the fourier plane (i.e., the plane including the confocal point O).

As shown in fig. 22 a, the laser beam transmitted through the 1 st branch pattern displayed on the liquid crystal layer of the reflective spatial light modulator 403 is branched into a plurality of (3 in this case) laser beams by the 1 st branch pattern. Each of the branched laser beams reaches a fourier surface (a surface including the confocal point O) via the 1 st lens 441 a. A light shielding plate 420 is provided on the fourier plane. Then, the laser light diffused through the confocal point O passes through the 2 nd lens 441b, is condensed by the condensing optical system 404 on the power meter 700, and output measurement is performed by the power meter 700 (output measurement processing at the time of light shielding).

Here, in the light-blocking output measurement process, the position of the light blocking plate 420 provided on the fourier plane is continuously changed. For example, as shown in fig. 22 b, in the first STEP (STEP1) of the light-shielded output measurement process, the light shielding plate 420 is disposed at a position where none of the branched laser beams (-1, 0, 1) is shielded. In this case, the power meter 700 measures output data P1 including the outputs of all the laser beams (-1 time, 0 time, 1 time). In the next STEP (STEP2), the light blocking plate 420 is disposed at a position where only 1 laser beam of the branched laser beams (-1, 0, 1) is blocked. In this case, in the power meter 700, output data P2 including outputs of 2 lasers (-1 time, 0 time) is measured. In the last STEP (STEP3), the light blocking plate 420 is disposed at a position where the 0 th and 1 st laser beams are blocked out from the branched laser beams (-1 st, 0 th, and 1 st). In this case, in the power meter 700, output data P3 including the output of 1 laser (-1 time) is measured.

In this way, by performing the measurement by the power meter 700 while blocking a part of the laser light by the light shielding plate 420, the output ratio of the laser light of-1 time among all the laser light of (-1 time, 0 time, 1 time) is P3/P1, the output ratio of the laser light of 0 time is (P2-P3)/P1, and the output ratio of the laser light of +1 time is (P1-P2)/P1, it is possible to derive the actual output measurement values of the respective laser light after branching. The arrangement of the light shielding plates 420 may be changed manually or automatically by the control of the controller 450.

According to such a laser processing method, the laser light is emitted in a state where the 1 st branching pattern set according to the output target value of each laser light after branching is set in the reflective spatial light modulator 403, the laser light branched into a plurality of pieces by the 1 st branching pattern is measured by the power meter 700, and the output actual measurement value of each laser light after branching is derived based on the measurement result. Then, in the present laser processing method, the balance parameter for generating the 2 nd branch pattern in which the output measured value is close to the output target value is generated and output. With this configuration, the balance parameter for generating the 2 nd branch pattern for bringing the output measured value actually measured by the power meter 700 close to the output target value is generated. In this way, by generating the balance parameter so that the actually measured output approaches the target value, and correcting the calculation algorithm using the balance parameter at the time of the machining process, the 2 nd branch pattern capable of bringing the output of the branch light closer to the output target value than the 1 st branch parameter is generated, whereby the output of the branch light can be appropriately adjusted to a desired value. As described above, according to the laser processing method, the output of the branched light can be adjusted to a desired value, and the processing quality can be improved.

In the step2, a light-blocking output measurement process is performed in which a part of each branched laser beam is blocked by the light blocking plate 420 and an output is measured by the power meter 700, and in this light-blocking output measurement process, the output is measured by the power meter 700 while changing the range of the laser beam blocked by the light blocking plate 420. In this way, by measuring the output of each laser beam by the power meter 700 while changing the range of the laser beam blocked by the light blocking plate 420, the output of each laser beam after branching can be appropriately derived.

Claims (9)

1. A laser processing apparatus is characterized in that,

a laser processing apparatus for forming a modified region in an object by irradiating the object with laser light,

the method comprises the following steps:

a light source for emitting the laser light;

a spatial light modulator for modulating the laser light emitted from the light source;

a detection unit that detects reflected light of the laser beam from the object; and

a control part for controlling the operation of the display device,

the control unit is configured to execute:

a1 st process of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation algorithm, setting and displaying the generated 1 st branching pattern on the spatial light modulator;

a2 nd process of controlling the light source so as to emit the laser light in a state where the 1 st branch pattern is displayed on the spatial light modulator;

a 3 rd process of controlling the detection unit so as to detect the reflected light of each laser beam branched by the 1 st branching pattern;

a 4 th process of deriving an output actual measurement value of each laser beam after the branching based on a detection result of the detection unit, and generating a correction parameter for correcting the calculation algorithm and generating a2 nd branching pattern as a branching pattern for bringing the output actual measurement value close to the output target value; and

and 5, modifying the calculation algorithm through the modification parameters, generating the 2 nd branch pattern based on the modified calculation algorithm, and setting and displaying the generated 2 nd branch pattern on the spatial light modulator for the machining process.

2. Laser processing apparatus according to claim 1,

the control part is used for controlling the operation of the motor,

in the 1 st processing, a plurality of types of the 1 st branching patterns in which combinations of output target values of the branched laser beams are different from each other are generated,

in the 4 th process, the correction parameter common to at least 2 of the 1 st branching patterns included in the plurality of types of 1 st branching patterns is generated.

3. Laser processing apparatus according to claim 2,

in the 4 th process, the control unit groups the plurality of types of 1 st branching patterns according to the degree of approximation of the branching parameter, and generates the common correction parameter for each group.

4. Laser processing apparatus according to claim 3,

the control unit performs the grouping according to the degree of approximation of the output target value as the branch parameter in the 4 th process.

5. Laser processing apparatus according to claim 3 or 4,

in the 5 th process, the control unit acquires information indicating a branch parameter in the machining process, and corrects the calculation algorithm based on the correction parameter of the group corresponding to the branch parameter.

6. The laser processing apparatus according to any one of claims 1 to 5,

the control unit generates the 1 st branching pattern for branching the laser beam to different positions in a vertical direction that is a thickness direction of the object in the 1 st processing.

7. A laser processing method is characterized in that,

a laser processing method for forming a modified region in an object by irradiating the object with a laser beam,

the method comprises the following steps:

a1 st step of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation algorithm, and setting and displaying the generated 1 st branching pattern on a spatial light modulator;

a2 nd step of emitting laser light to the spatial light modulator on which the 1 st branch pattern is displayed, and irradiating the object with the laser light branched into a plurality of parts according to the 1 st branch pattern;

a 3 rd step of detecting reflected light from the object of each of the branched laser beams;

a 4 th step of deriving an output actual measurement value of each laser beam after branching based on a detection result of the reflected light, and generating a correction parameter for correcting the calculation algorithm and generating a2 nd branching pattern as a branching pattern for bringing the output actual measurement value close to the output target value; and

and a 5 th step of correcting the calculation algorithm according to the correction parameter, generating the 2 nd branch pattern based on the corrected calculation algorithm, and setting and displaying the generated 2 nd branch pattern on the spatial light modulator for use in a machining process.

8. A laser processing method is characterized in that,

the method comprises the following steps:

a1 st step of generating a1 st branching pattern corresponding to an output target value of each of the branched laser beams as a branching pattern for branching the laser beams into a plurality of parts based on a predetermined calculation algorithm, and setting and displaying the generated 1 st branching pattern on a spatial light modulator;

a2 nd step of emitting laser light to the spatial light modulator on which the 1 st branching pattern is displayed, and measuring the laser light branched into a plurality by the 1 st branching pattern by a power meter to derive actual output measurement values of the branched laser lights; and

and a 3 rd step of generating and outputting a correction parameter for generating a2 nd branch pattern as a branch pattern for correcting the calculation algorithm and bringing the output measured value closer to the output target value.

9. The laser processing method according to claim 8, wherein:

in the step2, a light-blocking output measurement process is performed in which a part of each of the branched laser beams is blocked by a light blocking plate and an output is measured by the power meter, and in the light-blocking output measurement process, the output is measured by the power meter while changing a range of the laser beams blocked by the light blocking plate.

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