Laser processing apparatus and laser processing method

Abstract

The laser processing device is configured to execute: a first process of generating a first branch pattern based on a prescribed calculation formula and causing the generated first branch pattern to be displayed on a reflective spatial light modulator; a second process of controlling a light source unit to emit laser light; a third process of controlling a detection unit in a manner of detecting reflected light of each of the laser lights branched using the first branch pattern; a fourth process of deriving an output measured value of each of the laser lights after branching and generating a balance parameter involved in generation of a branch pattern, i.e., a second branch pattern, that causes the output measured value to approach an output target value; and a fifth process of correcting the calculation formula based on the balance parameter, generating the second branch pattern based on the corrected calculation formula, and setting and displaying the second branch pattern on the reflective spatial light modulator for use in a processing process.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser processing apparatus and a laser processing method. BACKGROUND

[0002] In Japanese Patent No. 6620976, a laser processing apparatus including a laser light source, a spatial light modulator, and a condensing correction unit different from the spatial light modulator is described. Such a laser processing apparatus forms a modification region inside an object (wafer) by irradiation of laser light, thereby performing dicing and peeling of the object, and the like. In the technology described in Patent Document 1, a modification region is formed inside the object by irradiation of laser light, and a part of reflected light from a condensing point is imaged, and a positional deviation amount of the condensing point is detected based on the imaging result, and a modulation pattern in the spatial light modulator is adjusted so as to make the positional deviation small. SUMMARY

[0003] In the laser processing apparatus as described above, sometimes a branch pattern is set in the spatial light modulator, and laser light is branched in accordance with the branch pattern, so as to form a plurality of modification regions at the same time. The branch pattern is set, for example, in accordance with an output target value of each laser light after branching. Here, for example, in the case where the laser light is branched using the spatial light modulator, due to influences of optical characteristics of the spatial light modulator itself and optical characteristics such as that the transmission regions of each branched light in the lens are different from each other, or individual differences of optical elements, or the like, a phenomenon that the output of each laser light after branching does not become the above-described output target value (design value) occurs. Such a phenomenon is difficult to completely avoid. The output of each laser light after branching does not become the intended value, and thus the amount of cracks extending from the modification region does not become the desired amount of cracks, and it is possible that the object is not diced and peeled (deterioration of processing quality). Therefore, a technical problem of the present application is to provide a laser processing apparatus and a laser processing method capable of improving the processing quality by adjusting the output of the branched light to the desired value.

[0004] The laser processing apparatus of one embodiment of the present application is a laser processing apparatus that forms a modified region in an object by irradiating the object with laser light, and includes a light source that emits laser light; a spatial light modulator that modulates the laser light emitted from the light source; a detection unit that detects reflected light of the laser light from the object; and a control unit that is configured to perform: a first process of generating a first branch pattern corresponding to an output target value of each of the branched laser lights as a branch pattern that branches the laser light into a plurality of laser lights, based on a predetermined calculation algorithm, and setting and displaying the generated first branch pattern in the spatial light modulator; a second process of controlling the light source to emit the laser light in a state where the first branch pattern is displayed in the spatial light modulator; a third process of controlling the detection unit to detect the reflected light of each of the branched laser lights using the first branch pattern; a fourth process of deriving an output measured value of each of the branched laser lights based on a detection result of the detection unit, generating a correction parameter involved in generation of a second branch pattern that is a branch pattern for making the output measured value close to the output target value, and a correction algorithm; and a fifth process of correcting the calculation algorithm according to the correction parameter, generating the second branch pattern based on the corrected calculation algorithm, and setting and displaying the generated second branch pattern in the spatial light modulator for a processing procedure.

[0005] In the laser processing apparatus of one embodiment of the present application, the laser light is emitted in a state where the first branch pattern generated based on the output target value of each of the branched laser lights is displayed in the spatial light modulator, the reflected light from the object is detected, and the output measured value of each of the laser lights is derived based on the detection result. Thus, in the laser processing apparatus, the correction parameter involved in generation of the second branch pattern that makes the output measured value close to the output target value is generated, the second branch pattern is generated by a calculation algorithm corrected by the correction parameter, and the second branch pattern is displayed in the spatial light modulator for a processing procedure. According to such a structure, the correction parameter for generating the second branch pattern that makes the output measured value estimated with high accuracy based on actually detected reflected light close to the output target value is generated. Thus, at the time of the processing procedure, the calculation algorithm is corrected with the correction parameter, the second branch pattern that can make the output of the branched light closer to the output target value than the first branch pattern is generated, and thus the output of the branched light can be adjusted to a desired value as appropriate. As described above, according to the laser processing apparatus of one embodiment of the present application, the output of the branched light can be adjusted to a desired value, and the processing quality can be improved.

[0006] The control section can generate, in the first process, a plurality of first branch patterns in which the combinations of the output target values of the respective branches after the branching are different from each other, and generate, in the fourth process, a common correction parameter involved in at least two first branch patterns included in the plurality of first branch patterns. In this way, by generating a common correction parameter for a plurality of first branch patterns in which the conditions of the output target values are different from each other, it is possible to generate unique second branch patterns using the same correction parameter, and it is possible to facilitate the generation and management of the correction parameter compared to a case in which a correction parameter is generated for each first branch pattern.

[0007] The control section can group, in the fourth process, the plurality of first branch patterns in accordance with the degrees of approximation of the branching parameters, and generate a common correction parameter for each group. For example, in a case in which one common correction parameter is generated for all of the first branch patterns, in a case in which the first branch patterns included in the group differ greatly from each other in the branching parameters, and the like, it is not possible to sufficiently improve the accuracy of all of the second branch patterns (the accuracy of causing the outputs of the branched lights to approximate the output target values) by correcting the calculation algorithm using the generated common correction parameter. In this regard, by generating a common correction parameter for a group in which the branching parameters are approximate, and generating another correction parameter between groups in which the branching parameters are not approximate, it is possible to ensure the accuracy of the second branch patterns (the accuracy of causing the outputs of the branched lights to approximate the output target values).

[0008] The control section can group, in the fourth process, the plurality of first branch patterns in accordance with the degrees of approximation of the output target values as the branching parameters. Thereby, a common correction parameter is generated for a group in which the output target values are approximate, and it is possible to ensure the accuracy of the second branch patterns (the accuracy of causing the outputs of the branched lights to approximate the output target values).

[0009] The control section can acquire, in the fifth process, information indicating the branching parameters in the machining process, and correct the calculation algorithm in accordance with the correction parameter of the group corresponding to the branching parameters. Thereby, it is possible to perform the machining process using the second branch pattern generated by the calculation algorithm corrected by the correction parameter appropriate for the branching parameters in the machining process, and it is possible to improve the machining quality.

[0010] The control section can generate, in the first process, a first branch pattern in which the laser is branched to different positions in the vertical direction of the thickness direction of the object. In actual machining, there is a case in which the laser is branched in the vertical direction (longitudinal branching), and by generating a first branch pattern related to this longitudinal branching, it is possible to generate a correction parameter involved in the generation of a second branch pattern that can cause the outputs of the branched lights in the case of the longitudinal branching to appropriately approximate the output target values.

[0011] The laser processing method of one embodiment of the present application is a laser processing method in which a modified region is formed in an object by irradiation of laser light, and includes: a first step of generating, based on a prescribed calculation algorithm, a first branch pattern corresponding to output target values of the respective pieces of laser light branched into a plurality of pieces, setting and displaying the generated first branch pattern in a spatial light modulator; a second step of emitting laser light to the spatial light modulator on which the first branch pattern is displayed, and irradiating the laser light branched into a plurality of pieces according to the first branch pattern to the object; a third step of detecting reflected light from the object of the respective pieces of laser light branched; a fourth step of deriving output measured values of the respective pieces of laser light branched, based on the detection results of the reflected light, generating a correction parameter involved in generation of a second branch pattern which is a branch pattern for making the output measured values close to the output target values, and a correction calculation algorithm; and a fifth step of correcting the calculation algorithm according to the correction parameter, generating the second branch pattern based on the corrected calculation algorithm, and setting and displaying the generated second branch pattern in the spatial light modulator for a processing procedure.

[0012] The laser processing method of another embodiment of the present application includes: a first step of generating, based on a prescribed calculation algorithm, a first branch pattern corresponding to output target values of the respective pieces of laser light branched into a plurality of pieces, setting and displaying the generated first branch pattern in a spatial light modulator; a second step of emitting laser light to the spatial light modulator on which the first branch pattern is displayed, and measuring the laser light branched into a plurality of pieces by the first branch pattern with a power meter, thereby deriving output measured values of the respective pieces of laser light branched; and a third step of generating and outputting a correction parameter involved in generation of a second branch pattern which is a branch pattern for making the output measured values close to the output target values.

[0013] In the laser processing method of another embodiment of the present application, laser light is emitted in a state where a first branch pattern set in accordance with output target values of the respective pieces of laser light branched is set in a spatial light modulator, and the laser light branched into a plurality of pieces by the first branch pattern is measured with a power meter, thereby deriving output measured values of the respective pieces of laser light branched based on the measurement results. In this laser processing method, a correction parameter involved in generation of a second branch pattern which is a branch pattern for making the output measured values close to the output target values is generated and output. According to such a structure, a correction parameter for generating a second branch pattern in which the output measured by the power meter is made close to the output target value is generated. Thus, by generating a correction parameter in such a manner that the actually measured output is made close to the target value, the calculation algorithm is corrected by the correction parameter at the time of a processing procedure, a second branch pattern in which the output of the branched light is made closer to the output target value than the first branch pattern is generated, and thus the output of the branched light can be appropriately adjusted to a desired value. As described above, according to the laser processing method of one embodiment of the present application, the output of the branched light can be adjusted to a desired value, and the processing quality can be improved.

[0014] In the laser processing method of the other aspect described above, the light-shielded-time output measurement process in which the range of the laser light shielded by the light shield is changed and the output is measured by the power meter can be performed in the second step while shielding the branched laser light by the light shield and measuring the output by the power meter. In this way, by changing the range of the laser light shielded by the light shield and measuring the output by the power meter, respectively, the output of the branched laser light can be appropriately derived.

[0015] According to the present application, by adjusting the output of the branched light to a desired value, the processing quality can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a perspective view of a laser processing apparatus of an embodiment.

[0017] Figure 2 is a front view of a laser processing apparatus shown in Figure 1

[0018] Figure 3 is a front view of a laser processing head of a laser processing apparatus shown in Figure 1

[0019] Figure 4 is a side view of a laser processing head shown in Figure 3

[0020] Figure 5 is a structural view of an optical system of a laser processing head shown in Figure 3

[0021] Figure 6 is a plan view for explaining a plurality of modified light points.

[0022] Figure 7 is a view showing one example of a setting screen of a GUI.

[0023] Figure 8 is a view showing an example of a manager mode of a setting screen of a GUI.

[0024] Figure 9 is a table showing the error of the measured value with respect to the design value in each output ratio at the time of 2-point branching.

[0025] Figure 10 is a table showing the error of the measured value with respect to the design value in each output ratio at the time of 3-point branching.

[0026] Figure 11 is a table showing the error of the measured value with respect to the design value in each output ratio at the time of 4-point branching.​​​​

[0027] Figure 12 is a diagram illustrating a manner of longitudinal branching.

[0028] Figure 13 is a table showing errors of measured values with respect to design values at each output ratio in a case where the balancing parameter taken without longitudinal branching is applied to processing with longitudinal branching (VD16).

[0029] Figure 14 is a table showing errors of measured values with respect to design values at each output ratio in a case where the balancing parameter taken with longitudinal branching (VD16) is applied to processing with longitudinal branching (VD16).

[0030] Figure 15 is a table showing a relationship between the amount of longitudinal branching and the maximum error.

[0031] Figure 16 is a table showing errors of measured values with respect to design values at each output ratio in a case where the balancing parameter is applied to each region.

[0032] Figure 17 is a diagram illustrating use of the balancing parameter corresponding to the branching parameter.

[0033] Figure 18 is a diagram illustrating use of the balancing parameter corresponding to the branching parameter.

[0034] Figure 19 is a flowchart illustrating a generation process of a branching pattern to which the balancing parameter is applied.

[0035] Figure 20 is a flowchart illustrating a generation process of a branching pattern to which the balancing parameter is applied.

[0036] Figure 21 is a schematic configuration diagram of a laser processing apparatus of a modification example.

[0037] Figure 22 is a diagram illustrating derivation of outputs of each laser after branching using a power meter. DETAILED DESCRIPTION

[0038] Hereinafter, an embodiment of the present application will be described in detail with reference to the drawings. In each drawing, the same or equivalent portions are denoted by the same reference numerals, and repetitive description will be omitted.

[0039] First, the basic structure of the laser processing apparatus will be described.

[0040] [BASIC STRUCTURE OF LASER PROCESSING APPARATUS]

[0041] As Figure 1As shown, the laser processing apparatus 1 includes a plurality of moving mechanisms 5, 6, a support section 7, a pair of laser processing heads 10A, 10B, a light source unit 8, and a control section 9. Note that the following describes an example in which the laser processing heads are a pair, but the laser processing heads can be only one. Hereinafter, a first direction is referred to as an X direction, a second direction perpendicular to the first direction is referred to as a Y direction, and a third direction perpendicular to the first direction and the second 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.

[0042] The moving mechanism 5 has a fixed section 51, a moving section 53, and a mounting section 55. The fixed section 51 is mounted to the apparatus frame la. The moving section 53 is mounted to a rail provided in the fixed section 51 and is movable in the Y direction. The mounting section 55 is mounted to a rail provided in the moving section 53 and is movable in the X direction.

[0043] The moving mechanism 6 has a fixed section 61, a pair of moving sections 63, 64, and a pair of mounting sections 65, 66. The fixed section 61 is mounted to the apparatus frame la. The pair of moving sections 63, 64 are respectively mounted to rails provided in the fixed section 61 and are respectively independently movable in the Y direction. The mounting section 65 is mounted to a rail provided in the moving section 63 and is movable in the Z direction. The mounting section 66 is mounted to a rail provided in the moving section 64 and is movable in the Z direction. That is, the pair of mounting sections 65, 66 are respectively movable in the Y direction and the Z direction with respect to the apparatus frame la.

[0044] The support section 7 is mounted to a rotation shaft provided in the mounting section 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 section 7 is movable in the X direction and the Y direction and is rotatable about an axis parallel to the Z direction as a center line. The support section 7 supports an object 100. The object 100 is, for example, a wafer.

[0045] As shown in Figs. 1 and 2, the laser processing apparatus 1 includes a plurality of moving mechanisms 5, 6, a support section 7, a pair of laser processing heads 10A, 10B, a light source unit 8, and a control section 9. Note that the following describes an example in which the laser processing heads are a pair, but the laser processing heads can be only one. Hereinafter, a first direction is referred to as an X direction, a second direction perpendicular to the first direction is referred to as a Y direction, and a third direction perpendicular to the first direction and the second 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. Figure 1 and Figure 2 The laser processing head 10A is mounted to the mounting section 65 of the moving mechanism 6. The laser processing head 10A irradiates the laser LI toward the object 100 supported by the support section 7 in a state of facing the support section 7 in the Z direction. The laser processing head 10B is mounted to the mounting section 66 of the moving mechanism 6. The laser processing head 10B irradiates the laser L2 toward the object 100 supported by the support section 7 in a state of facing the support section 7 in the Z direction.

[0046] The light source unit 8 has a pair of light sources 81, 82. The light source 81 outputs the laser LI. The laser LI is emitted from an emission section 81a of the light source 81 and guided to the laser processing head 10A through an optical fiber 2. The light source 82 outputs the laser L2. The laser L2 is emitted from an emission section 82a of the light source 82 and guided to the laser processing head 10B through another optical fiber 2.

[0047] The control section 9 controls each section (the support section 7, the plurality of moving mechanisms 5, 6, the pair of laser processing heads 10A, 10B, and the light source unit 8, etc.) of the laser processing apparatus 1. The control section 9 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control section 9, reading and writing of data in the memory and the storage, and communication based on the communication device are controlled by the processor, and software (a program) read into the memory and the like is executed by the processor. Thus, the control section 9 realizes various functions.

[0048] An example of processing performed by the laser processing apparatus 1 configured as described above will be described. One example of the processing is an example of forming a modification region in the inside of the object 100 along a plurality of lines set in a lattice shape in order to cut the object 100 as a wafer into a plurality of chips. In addition, the laser processing apparatus 1 can also perform peeling processing of peeling a part of the object 100.

[0049] First, the moving mechanism 5 moves the support section 7 along the X direction and the Y direction, respectively, so that the support section 7 supporting the object 100 is opposed to the pair of laser processing heads 10A, 10B in the Z direction. Next, the moving mechanism 5 rotates the support section 7 with 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 aligned along the X direction.

[0050] Next, the moving mechanism 6 moves the laser processing head 10A along the Y direction, so that the focal point (a part of the focal region) of the laser L1 is positioned on one line extending in one direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction, so that the focal point of the laser L2 is positioned on another line extending in one direction. Next, the moving mechanism 6 moves the laser processing head 10A along the Z direction, so that the focal point of the laser L1 is positioned in the inside of the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction, so that the focal point of the laser L2 is positioned in the inside of the object 100.

[0051] Next, the light source 81 outputs the laser L1, the laser processing head 10A irradiates the laser L1 toward the object 100, and the light source 82 outputs the laser L2, the laser processing head 10B irradiates the laser L2 toward the object 100. At the same time, the moving mechanism 5 moves the support section 7 along the X direction, so that the focal point of the laser L1 relatively moves along one line extending in one direction and the focal point of the laser L2 relatively moves along another line extending in one direction. In this way, the laser processing apparatus 1 forms a modification region in the inside of the object 100 along each of a plurality of lines extending in one direction in the object 100.

[0052] Next, the moving mechanism 5 rotates the support section 7 with an axis parallel to the Z direction as a center line, so that a plurality of lines extending in another direction orthogonal to one direction in the object 100 are made to align along the X direction.

[0053] Next, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the focal point of the laser LI is located on a line extending in another direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction so that the focal point of the laser L2 is located on another line extending in another direction. Next, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the focal point of the laser LI is located inside the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the focal point of the laser L2 is located inside the object 100.

[0054] Next, the light source 81 outputs the laser LI, the laser processing head 10A irradiates the laser LI toward the object 100, and the light source 82 outputs the laser L2, the laser processing head 10B irradiates the laser L2 toward the object 100. At the same time, the moving mechanism 5 moves the support section 7 along the X direction so that the focal point of the laser LI relatively moves along a line extending in another direction and the focal point of the laser L2 relatively moves along another line extending in another direction. In this way, the laser processing apparatus 1 forms a modified region inside the object 100 along each of a plurality of lines extending in another direction orthogonal to one direction in the object 100.

[0055] In addition, in one example of the above processing, the light source 81 outputs the laser LI having a transmissivity with respect to the object 100, for example, by a pulse oscillation method, and the light source 82 outputs the laser L2 having a transmissivity with respect to the object 100, for example, by a pulse oscillation method. When such lasers are condensed inside the object 100, the laser is particularly absorbed in a portion corresponding to the focal point of the laser, and a modified region is formed inside the object 100. The modified region is a region in which density, refractive index, mechanical strength, other physical characteristics, and the like are different from those of a non-modified region around the modified region. As the modified region, for example, there are a fusion-processed region, a crack region, an insulation-destroyed region, a refractive index variation region, and the like.

[0056] If a laser output via pulse oscillation is applied to an object 100, and the laser's focal point moves relative to a line set on the object 100, multiple modified light spots are formed and arranged in a row along the line. A single modified light spot is formed by irradiation with a single laser pulse. A row of modified regions is a collection of multiple modified light spots arranged in a row. Adjacent modified light spots may be connected or separated depending on the relative movement speed of the laser's focal point relative to the object 100 and the laser's repetition frequency. The shape of the set line is not limited to a lattice pattern; it can also be a ring, a straight line, a curve, or a combination of at least one of these.

[0057] [Structure of laser processing head]

[0058] like Figure 3 and Figure 4 As shown, the laser processing head 10A includes a housing 11, an incident part 12, an adjustment part 13, and a focusing part 14.

[0059] The housing 11 has a first wall portion 21 and a second wall portion 22, a third wall portion 23 and a fourth wall portion 24, and a fifth wall portion 25 and a sixth wall portion 26. The first wall portion 21 and the second wall portion 22 are opposite to each other in the X direction. The third wall portion 23 and the fourth wall portion 24 are opposite to each other in the Y direction. The fifth wall portion 25 and the sixth wall portion 26 are opposite to each other in the Z direction.

[0060] In the laser processing head 10A, the first wall portion 21 is located on the opposite side of the fixed portion 61 of the moving mechanism 6, and the second wall portion 22 is located on the side of the fixed portion 61. The third wall portion 23 is located on the side of the mounting portion 65 of the moving mechanism 6, and the fourth wall portion 24 is located on the opposite side of the mounting portion 65 and on the side of the laser processing head 10B (see reference). Figure 2 The fifth wall portion 25 is located on the opposite side of the support portion 7, and the sixth wall portion 26 is located on the side of the support portion 7.

[0061] The housing 11 is configured such that it is mounted on the mounting portion 65 with the third wall portion 23 disposed on the mounting portion 65 side of the moving mechanism 6. Specifically, as described below, the mounting portion 65 has a base plate 65a and a mounting plate 65b. The base plate 65a is mounted on a track provided on the moving portion 63 (see reference). Figure 2 Mounting plate 65b is vertically mounted on the end of the laser processing head 10B side of base plate 65a (see reference). Figure 2 With the third wall portion 23 in contact with the mounting plate 65b, the bolt 28 is screwed into the mounting plate 65b via the base 27, thereby mounting the housing 11 onto the mounting portion 65. The base 27 is respectively provided on the first wall portion 21 and the second wall portion 22. The housing 11 can be attached to and detached from the mounting portion 65.

[0062] The incidence portion 12 is attached to the fifth wall portion 25. The incidence portion 12 causes the laser light LI to be incident into the casing 11. The incidence portion 12 is biased to the second wall portion 22 side (one wall portion side) in the X direction and is biased to the fourth wall portion 24 side in the Y direction.

[0063] The incidence portion 12 is configured so that the connection end portion 2a of the optical fiber 2 can be connected. A collimator lens that collimates the laser light LI emitted from the emission end of the optical fiber is provided at the connection end portion 2a of the optical fiber 2, and an isolator that suppresses return light is not provided. The isolator is provided midway through the optical fiber on the light source 81 side from the connection end portion 2a. Thus, miniaturization of the connection end portion 2a, and further, miniaturization of the incidence portion 12 are achieved. In addition, the isolator can be provided at the connection end portion 2a of the optical fiber 2.

[0064] The adjustment portion 13 is disposed inside the casing 11. The adjustment portion 13 adjusts the laser light LI incident from the incidence portion 12. Each structure that the adjustment portion 13 has is attached to an optical base 29 provided inside the casing 11. The optical base 29 is attached to the casing 11 in a manner that divides the region inside the casing 11 into a region on the third wall portion 23 side and a region on the fourth wall portion 24 side. The optical base 29 is integrated with the casing 11. Each structure that the adjustment portion 13 has is attached to the optical base 29 on the fourth wall portion 24 side. Details of each structure that the adjustment portion 13 has are described later.

[0065] The condensing portion 14 is disposed on the sixth wall portion 26. Specifically, the condensing portion 14 is disposed on the sixth wall portion 26 in a state of being inserted through a hole 26a formed in the sixth wall portion 26 (see Figure 5 ). The condensing portion 14 causes the laser light LI adjusted by the adjustment portion 13 to be emitted outside the casing 11 while condensing the laser light LI. The condensing portion 14 is biased to the second wall portion 22 side (one wall portion side) in the X direction and is biased to the fourth wall portion 24 side in the Y direction.

[0066] As shown in Figure 5 , the adjustment portion 13 has an attenuator 31, a beam expander 32, and a mirror 33. The incidence portion 12, and the attenuator 31, the beam expander 32, and the mirror 33 of the adjustment portion 13 are disposed on a straight line (first straight line) Al extending in the Z direction. The attenuator 31 and the beam expander 32 are disposed between the incidence portion 12 and the mirror 33 on the straight line Al. The attenuator 31 adjusts the output of the laser light LI incident from the incidence portion 12. The beam expander 32 enlarges the diameter of the laser light LI whose output has been adjusted by the attenuator 31. The mirror 33 reflects the laser light LI whose diameter has been enlarged by the beam expander 32.

[0067] The adjustment section 13 also has a reflection-type spatial light modulator 34 and an imaging optical system 35. The reflection-type spatial light modulator 34 and the imaging optical system 35 of the adjustment section 13, and the condensing section 14 are arranged on a straight line (second straight line) A2 extending in the Z direction. The reflection-type spatial light modulator 34 is, for example, a reflection-type liquid crystal on silicon (LCOS: Liquid Crystal on Silicon) spatial light modulator (SLM: Spatial Light Modulator). The reflection-type spatial light modulator 34 modulates the laser light LI reflected by the mirror 33. The reflection-type spatial light modulator 34 modulates the laser light LI in accordance with a displayed modulation pattern. A branching pattern for branching the laser light LI into a plurality of laser lights is set and displayed in the reflection-type spatial light modulator 34. Thus, the laser light LI incident on the reflection-type spatial light modulator 34 is branched into a plurality of laser lights in the reflection-type spatial light modulator 34 (refer to Figure 6 The imaging optical system 35 is composed of three or more lenses.

[0068] The straight line Al and the straight line A2 are located on a plane perpendicular to the Y direction. The straight line Al is located on the second wall section 22 side (one wall section side) with respect to the straight line A2. In the laser processing head 10A, the laser light LI is incident on the housing 11 from the incidence section 12 and travels on the straight line Al, is reflected by the mirror 33 and the reflection-type spatial light modulator 34 in this order, travels on the straight line A2, and is emitted to the outside of the housing 11 from the condensing section 14. In addition, the arrangement order of the attenuator 31 and the beam expander 32 can be reversed. In addition, the attenuator 31 can be arranged between the mirror 33 and the reflection-type spatial light modulator 34. In addition, the adjustment section 13 can have other optical sections (for example, a turning mirror arranged before the beam expander 32, and the like).

[0069] The laser processing head 10A also includes a dichroic mirror 15, a measurement section 16, a detection section 17, a drive section 18, and a circuit section 19.

[0070] The dichroic mirror 15 is arranged between the imaging optical system 35 and the condensing section 14 on the straight line A2. That is, the dichroic mirror 15 is arranged between the adjustment section 13 and the condensing section 14 in the housing 11. The dichroic mirror 15 is attached to the optical base 29 on the fourth wall section 24 side. The dichroic mirror 15 transmits the laser light LI. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 is, for example, preferably a cubic type, or a two-plate type arranged in a twisted relationship.

[0071] The measurement section 16 is disposed on the first wall section 21 side (the side opposite the one wall section side) with respect to the adjustment section 13 inside the housing 11. The measurement section 16 is attached to the optical base 29 on the fourth wall section 24 side. The measurement section 16 outputs measurement light L10 for measuring the distance from the surface of the object 100 (for example, the surface on the side on which the laser light L1 is incident) to the condensing section 14, and detects the measurement light L10 reflected on the surface of the object 100 via the condensing section 14. That is, the measurement light L10 output from the measurement section 16 is irradiated onto the surface of the object 100 via the condensing section 14, and the measurement light L10 reflected on the surface of the object 100 is detected by the measurement section 16 via the condensing section 14.

[0072] More specifically, the measurement light L10 output from the measurement section 16 is reflected on the beam splitter 20 and the dichroic mirror 15 attached to the optical base 29 on the fourth wall section 24 side in this order, and is emitted outside the housing 11 from the condensing section 14. The measurement light L10 reflected on the surface of the object 100 is incident into the housing 11 from the condensing section 14, is reflected on the dichroic mirror 15 and the beam splitter 20 in this order, is incident into the measurement section 16, and is detected by the measurement section 16.

[0073] The detection section 17 is disposed on the first wall section 21 side (the side opposite the one wall section side) with respect to the adjustment section 13 inside the housing 11. The detection section 17 is attached to the optical base 29 on the fourth wall section 24 side. The detection section 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 the observation light L20 reflected on the surface of the object 100 via the condensing section 14. That is, the observation light L20 output from the detection section 17 is irradiated onto the surface of the object 100 via the condensing section 14, and the observation light L20 reflected on the surface of the object 100 is detected by the detection section 17 via the condensing section 14. The detection section 17 is, for example, a camera that detects (images) the reflected observation light L20.

[0074] More specifically, the observation light L20 output from the detection section 17 is reflected on the dichroic mirror 15 after passing through the beam splitter 20, and is emitted outside the housing 11 from the condensing section 14. The observation light L20 reflected on the surface of the object 100 is incident into the housing 11 from the condensing section 14, is reflected on the dichroic mirror 15, passes through the beam splitter 20, is incident into the detection section 17, and is detected by the detection section 17. Furthermore, the respective wavelengths of the laser light L1, the measurement light L10, and the observation light L20 are different from each other (at least the respective central wavelengths are offset from each other).

[0075] In addition, the detection section 17 detects a portion of the laser light L1 reflected on the surface of the object 100 (details are described later). The portion of the laser light L1 reflected on the surface of the object 100 refers to only a small amount of the laser light L1 reflected on the dichroic mirror 15 toward the detection section 17 among the laser light L1 reflected on the surface of the object 100.

[0076] The drive unit 18 is mounted on the optical base 29 on the fourth wall 24 side. The drive unit 18 moves the focusing part 14 disposed on the sixth wall 26 along the Z direction by, for example, the driving force of the piezoelectric element.

[0077] The circuit section 19 is disposed within the housing 11 on the third wall 23 side relative to the optical base 29. That is, the circuit section 19 is disposed within the housing 11 on the third wall 23 side relative to the adjustment section 13, the measurement section 16, and the detection section 17. The circuit section 19 is, for example, a plurality of circuit boards. The circuit section 19 processes the signals output from the measurement section 16 and the signals input to the reflective spatial light modulator 34. The circuit section 19 controls the drive section 18 based on the signals output from the measurement section 16. As an example, the circuit section 19 controls the drive section 18 based on the signals output from the measurement section 16 in a manner that maintains a fixed distance between the surface of the object 100 and the focusing section 14 (i.e., maintains a fixed distance between the surface of the object 100 and the focusing point of the laser L1). Furthermore, a connector (not shown) is provided in the housing 11, which connects the circuit section 19 to the control section 9 (see reference 1). Figure 1 Wiring for electrical connections, etc.

[0078] The laser processing head 10B, like the laser processing head 10A, includes a housing 11, an incident section 12, an adjustment section 13, a focusing section 14, a dichroic mirror 15, a measuring section 16, a detection section 17, a driving section 18, and a circuit section 19. However, as... Figure 2 As shown, the structures of the laser processing head 10B are configured such that they are symmetrical with respect to an imaginary plane passing through the midpoint between a pair of mounting portions 65 and 66 and perpendicular to the Y direction.

[0079] For example, the housing (first housing) 11 of the laser processing head 10A is mounted on the mounting portion 65 such that the fourth wall portion 24 is located on the laser processing head 10B side relative to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25. In contrast, the housing (second housing) 11 of the laser processing head 10B is mounted on the mounting portion 66 such that the fourth wall portion 24 is located on the laser processing head 10A side relative to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25.

[0080] The housing 11 of the laser processing head 10B is configured to be attached to the attachment portion 66 in a state where the third wall portion 23 is disposed on the attachment portion 66 side. Specifically, as described below. The attachment portion 66 has a base plate 66a and an attachment plate 66b. The base plate 66a is attached to the rail provided in the moving portion 63. The attachment plate 66b is vertically disposed at the end portion 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 third wall portion 23 is in contact with the attachment plate 66b. The housing 11 of the laser processing head 10B is detachable with respect to the attachment portion 66.

[0081] [Branching of laser]

[0082] Hereinafter, the branching of the laser for the purpose of cutting and peeling of the object 100 and the like will be described with reference to Figures 6 to 8 . As described above, the laser LI is branched in accordance with the branching pattern set and displayed in the reflective spatial light modulator 34.

[0083] Figure 6 is a view illustrating a plurality of modified spots SA in a case where the laser LI is branched into four. In the example illustrated in Figure 6 , the laser LI is branched so that a plurality of (four) modified spots SA are formed in the object 100 in a row along a tilt direction C2 that is tilted with respect to an orthogonal direction orthogonal to the processing direction CI. The branching of the laser LI is achieved by the branching pattern (modulation pattern) set and displayed in the reflective spatial light modulator 34 (refer to Figure 5 ).

[0084] In the illustrated example, the laser LI is branched into four beams, and four modified spots SA are formed. With respect to an adjacent pair of modified spots SA among the four modified spots SA after branching, the interval in the processing direction CI is a branching pitch Bpx, and the interval in the direction orthogonal to the processing direction CI is a branching pitch Bpy. With respect to a pair of modified spots SA formed by irradiation of the laser LI by two consecutive pulses, the interval in the processing direction CI is a pulse pitch PP. The angle between the processing direction CI and the tilt direction C2 is a branching angle a.

[0085] Figure 7 is a setting screen of the GUI 111 for achieving the branching of the laser LI as illustrated in Figure 6 . The GUI 111 functions as an input portion that receives input from a user. Figure 7The setting screen of the GUI 111 illustrated includes a machining condition selection button 211 that selects machining conditions, a branch number field 212 that inputs or selects the number of branches of the laser Ll, an index field 213 that inputs an index as a distance of movement from after laser machining along one machining line to the next machining line, an impression chart 214 that performs input or display of the number of branches and the index, a machining Z height field 215 that inputs the position of the modification spot SA in the Z direction, a machining speed field 216 that inputs the machining speed, and a condition switching method button 217 that selects the switching method of machining conditions.

[0086] In the machining condition selection button 211, a specific machining condition can be selected from among a plurality of options. According to the index field 213, in the case where the number of branches is one, the laser machining head 10A is caused to automatically move in the index direction by the input value. In the case where the number of branches is made greater than one, the laser machining head 10A is caused to automatically move in the index direction by an index amount based on the following calculation formula.

[0087] Index = (number of branches) x index input value

[0088] The impression chart 214 includes a display portion 214a of the index input value and an output input field 214b that inputs the output of each modification spot SA.

[0089] Figure 8 Fig. 7 is a diagram that illustrates an example of a manager mode of the setting screen of the GUI 111. Figure 8 The setting screen illustrated includes a branch direction selection button 221 that selects the branch direction of the laser Ll, a branch number field 222 that inputs or selects the number of branches of the laser Ll, a branch pitch input field 223 that inputs the branch pitch Bpx, a branch pitch column number input field 224 that inputs the number of columns of the branch pitch Bpx, a branch pitch input field 225 that inputs the branch pitch BPy, an index field 226 that inputs the index, an optical axis impression chart 227 based on the number of branches, a go-back selection button 228 that selects whether the scanning direction of the laser Ll is the one direction (go) or the other direction (back), and a balance adjustment start button 229 that automatically adjusts the balance of various values.

[0090] [Branch pattern correction processing]

[0091] In the laser processing apparatus 1 of the present embodiment, at a stage prior to the processing treatment (processing process) of forming a modified region in the object 100, based on a prescribed calculation formula (calculation algorithm), a first split pattern corresponding to the output ratio (output target value) of each of the split lasers is generated, the laser is emitted toward the object 100 in a state where the first split pattern is displayed on the reflective spatial light modulator 34, the reflected light of each of the split lasers using the first split pattern is detected, based on the detection result, the output measured value of each of the split lasers is derived, and the balance parameter (correction parameter) involved in the generation of the second split pattern that makes the output measured value close to the desired output ratio (output target value) is generated. Thus, at the time of the processing treatment, in the present laser processing apparatus 1, the second split pattern is generated based on the corrected calculation formula by the above balance parameter correction calculation formula, the second split pattern is set and displayed on the reflective spatial light modulator 34 for the processing treatment.

[0092] Thus, in the laser processing apparatus 1 of the present embodiment, the first split pattern generated based on the prescribed calculation formula is not directly used at the time of the processing treatment, but at a stage prior to the processing treatment, the output measured value of each of the split lasers in the case where the first split pattern is used is derived, the balance parameter involved in the generation of the second split pattern that reduces the error of the assumed output ratio from the output measured value is generated, at the time of the processing treatment, the calculation formula is corrected using the balance parameter, and the second split pattern generated based on the corrected calculation formula is used. Thereby, it is possible to appropriately adjust the output of the split light to the desired value (output ratio), and to improve the processing quality.

[0093] The above error (error of the assumed output ratio from the output measured value) before correction is, for example, generated due to the influence of the optical characteristics of the spatial light modulator itself, the optical characteristics in which the transmission regions of each of the split lights in the lens are different from each other, or the individual differences of the optical elements, and the like.

[0094] Figure 9 is a table indicating the error of the measured value of each of the output ratios at the time of 2-point splitting with respect to the design value (ideal output ratio). In Figure 9 the left graph indicates the error in the case where the above first split pattern is used without implementing correction based on the balance parameter. As Figure 9As shown in the left figure, without implementing corrections based on balance parameters, for example, when the design value for the output ratio of the two-point branch is 20:80, the measured value is 9:91 (error 11%); when the design value is 30:70, the measured value is 21:79 (error 9%); when the design value is 40:60, the measured value is 35:65 (error 5%); when the design value is 50:50, the measured value is 51:49 (error 1%); and when the design value is 60:40, the measured value is 65:35 (error 5%). The error increases, especially when the difference between the outputs of the two points of the branch is large.

[0095] Laser processing device 1 according to Figure 9 The error information shown in the left figure generates a balance parameter that makes the measured output value closer to the design value (ideal output ratio). This balance parameter modifies the calculation formula for generating the branch pattern, enabling the generation of a second branch pattern (a branch pattern that makes the measured output value closer to the design value) based on the modified formula. Figure 9 The right-hand figure shows the error when using the second branch pattern generated with adjustments based on the balance parameters. Figure 9 In the example shown in the right figure, by applying the balancing parameter—that is, by using the second branch parameter generated by correcting the calculation using the balancing parameter—the error in each output ratio is reduced, with the maximum error reduced to 3%. Furthermore, Figure 9 This represents the error when the first branch pattern is set to the condition of having no vertical branches, and when the processing using the second branch pattern is also set to the condition of having no vertical branches.

[0096] The effect of generating and applying the balancing parameters is not limited to 2-point branches; the same applies to other branch numbers. Figure 10 This is a table representing the error of the measured value relative to the design value in each output ratio when there is a 3-point branch. Figure 11 This is a table showing the error between the measured values ​​and the design values ​​for each output ratio in a 4-point branching configuration. For example... Figure 10 As shown in the left figure, without adjustments based on the balance parameters, the maximum error of each output ratio in the 3-point branch is 8%, but as... Figure 10 As shown in the right figure, by applying the balancing parameters, the maximum error of each output ratio in the 3-point branch is reduced to 3%. Additionally, as... Figure 11 As shown in the left figure, without implementing corrections based on balance parameters, the maximum error of each output ratio at the 4-point branch is 9%, but as... Figure 11 As shown in the right figure, by applying the balancing parameter, the maximum error of each output ratio in the 4-point branch is reduced to 3%.

[0097] The laser processing device 1 can also generate a first branch pattern that branches the laser in the Z direction (vertical direction) that is the thickness direction of the object 100 to different positions. Figure 12 is a diagram that illustrates a manner of longitudinal branching. Figure 12 (a) indicates each laser when 3-point branching without longitudinal branching, Figure 12 (b) indicates each laser when 3-point branching with longitudinal branching. In Figure 12 (a) and Figure 12 (b), the horizontal axis is the processing direction, and the vertical axis is the Z direction (vertical direction). As shown in Figure 12 (a), in the state without longitudinal branching, each laser after branching is irradiated to the same height in the Z direction. On the other hand, as shown in Figure 12 (b), in the state with longitudinal branching, each laser after branching is irradiated to different heights in the Z direction. Further, Figure 12 "longitudinal branching VD0" in Figure 12 (a) means no longitudinal branching, "longitudinal branching VD16" in (b) means longitudinal branching with a branching pitch of 16 μ in the Z direction.

[0098] Figure 13 is a table that indicates the error of the measured value with respect to the design value in each output ratio when 3-point branching in the case where the balance parameter obtained without longitudinal branching is applied to processing with longitudinal branching (VD16). In the left diagram of Figure 13 , the error in the case where the first branch pattern without longitudinal branching is used is indicated. In the right diagram of Figure 13 , the second branch parameter generated by correction of the balance parameter generated using the information of the error in the case where no longitudinal branching is applied as shown in the left diagram of Figure 13 is indicated, and the error in the case where processing with longitudinal branching (VD16) is performed is indicated. As described above, in the case where both the processing using the first branch pattern and the processing with the second branch pattern applied without longitudinal branching, in 3-point branching, as shown in the right diagram of Figure 10 , the maximum error can be reduced to 3%. On the other hand, in the case where the balance parameter is generated by the first branch pattern without longitudinal branching, and the processing with longitudinal branching (VD16) is performed using the second branch parameter generated by correction based on the balance parameter, as shown in the right diagram of Figure 13 , the maximum error becomes 4%. In this way, when the conditions of the balance parameter generation and the longitudinal branching of the processing are different, it can be considered that the error of the measured value with respect to the design value cannot be sufficiently reduced even if the balance parameter is applied.

[0099] Figure 14is a table showing errors of measured values with respect to design values in each output ratio at 3-point branching when the balance parameters obtained with the vertical branching (VD16) are applied to processing with the vertical branching (VD16). The processing using the 1st branching pattern and the processing applying the 2nd branching pattern are both set to have the vertical branching (VD16), and thus, as shown in the right drawing of Figure 14 , it is possible to reduce the maximum error to 3%. In this way, by making the conditions of the balance parameter generation and the vertical branching of the processing common, it is possible to sufficiently reduce the errors of the measured values with respect to the design values.

[0100] Figure 15 is a table showing the relationship between the amount of vertical branching and the maximum error. Figure 15 "Amount of vertical branching" in indicates the amount of vertical branching in the processing. Figure 15 "Maximum error" in indicates the maximum error of a certain output ratio in the case where the processing applying the balance parameters generated based on the 1st branching pattern of VD16 is implemented with the vertical branching indicated by "Amount of vertical branching". As shown in Figure 16 , in the case where the balance parameters generated based on the 1st branching pattern of VD16 are applied, the maximum error becomes the smallest (0.8%) in the case where the branching processing of VD16 is implemented. In addition, as shown in Figure 16 , in the case where the branching processing of VD2 is implemented with the balance parameters generated based on the 1st branching pattern of VD16 applied, the maximum error is also relatively small, which is 1.4%. In this way, even if the conditions of the balance parameter generation and the vertical branching of the processing are not consistent, in the case where the processing with the vertical branching is implemented, by using the balance parameters generated under the conditions with the vertical branching, it is possible to reduce the errors.

[0101] The laser processing device 1 can also generate a plurality of 1st branching patterns in which the combinations of the output ratios (output target values) of the respective lasers after branching are different from each other, and generate common balance parameters related to the plurality of 1st branching patterns. Here, for example, if the common balance parameters related to the respective output ratios are generated in such a manner that the errors with respect to the design values within a region A (a region surrounded by a quadrangle of a solid line) shown in the left drawing of Figure 16 , as shown in the left drawing of Figure 16 , although the errors in the region A are reduced to 1% or less, the errors in a region B (a region surrounded by a quadrangle of a single-dot chain line) and a region C (a region surrounded by a quadrangle of a broken line) different from the region A are increased to 3% to 6%. In this way, in the balance parameters generated in such a manner that the errors of a certain region are reduced, it is not possible to sufficiently reduce the errors of regions far from the certain region.

[0102] Therefore, the laser processing apparatus 1 can also perform grouping in accordance with the degree of approximation of the output ratio (output target value) as the branching parameter, and generate a common balancing parameter in units of groups. That is, the laser processing apparatus 1 can also generate a common balancing parameter in units of groups (regions) in which the output ratio is approximated. In Figure 16 In the right graph of FIG. 9, the error in the 3-point branching when one common balancing parameter is generated for each region A, B, C is shown. As shown in the right graph of FIG. 9, if a common balancing parameter is generated for each region A, B, C, the error between the design value and the measured value can be reduced to about 1% in all of the output ratios. In this way, by switching the balancing parameter in accordance with the output ratio used at the time of processing, the error of the measured value with respect to the design value can be reduced. Figure 16

[0103] Hereinafter, the functions of the control section 9 that implements the above-described branching pattern correction processing will be described in detail.

[0104] The control section 9 is configured to execute the following processing: a first processing of generating, based on a prescribed calculation formula (calculation algorithm), a first branching pattern corresponding to the output ratio (output target value) of each laser after branching as a branching pattern that branches laser into a plurality, and setting and displaying the generated first branching pattern in the reflective spatial light modulator 34; a second processing of controlling the light source unit 8 so that laser is emitted in a state in which the first branching pattern is displayed in the reflective spatial light modulator 34; a third processing of controlling the detection section 17 so as to detect the reflected light of each laser after branching by the first branching pattern; a fourth processing of deriving, based on the detection result of the detection section 17, the output measured value of each laser after branching, generating a balancing parameter (correction parameter) involved in the generation of a second branching pattern that is a branching pattern that makes the output measured value close to the desired output ratio (output target value) for correcting the calculation formula, and a fifth processing of generating the second branching pattern based on the corrected calculation formula by correcting the calculation formula by the balancing parameter, and setting and displaying the generated second branching pattern in the reflective spatial light modulator 34 for use in the processing.

[0105] In the first processing, the control section 9 decides the output ratio based on the information received in the setting screen (refer to FIGS. 11A and 11B) of the GUI 111, and sets the first branching pattern corresponding to the decided output ratio in the reflective spatial light modulator 34. The control section 9 generates the first branching pattern corresponding to the output ratio based on the calculation formula (calculation algorithm) stored in advance. The control section 9 can also generate a plurality of first branching patterns in which the combination of the output ratios of each laser after branching is different. In addition, the control section 9 can also generate a first branching pattern that performs longitudinal branching that branches laser to different positions in the Z direction (vertical direction) that is the thickness direction of the object 100. Figure 7 Figure 8 In the first processing, the control section 9 decides the output ratio based on the information received in the setting screen (refer to FIGS. 11A and 11B) of the GUI 111, and sets the first branching pattern corresponding to the decided output ratio in the reflective spatial light modulator 34. The control section 9 generates the first branching pattern corresponding to the output ratio based on the calculation formula (calculation algorithm) stored in advance. The control section 9 can also generate a plurality of first branching patterns in which the combination of the output ratios of each laser after branching is different. In addition, the control section 9 can also generate a first branching pattern that performs longitudinal branching that branches laser to different positions in the Z direction (vertical direction) that is the thickness direction of the object 100. ​​

[0106] In the 2nd process, the control section 9 controls the light source unit 8, for example, so that the laser is irradiated at an output at which the object 100 does not form a modified region (below the modification threshold) in a state in which the reflection-type spatial light modulator 34 displays the 1st branch pattern. Further, the branched laser can also be irradiated on an object (a modification processing object) different from the object 100 on which the laser processing is performed after the branch pattern modification processing.

[0107] In the 3rd process, the control section 9 controls the detection section 17 so that the reflected light of each of the branched lasers on the object 100 can be detected (imaged) at least during a period in which each of the branched lasers is irradiated on the object 100. The control section 9 acquires the image imaged by the detection section 17 from the detection section 17.

[0108] In the 4th process, the control section 9 estimates (derives) the output measured value of each of the lasers, for example, on the basis of the brightness of each point corresponding to each of the branched lasers in the imaged data acquired by the detection section 17. The control section 9 generates the balance parameter involved in the generation of the 2nd branch pattern that makes the output measured value close to the desired output ratio as a modification parameter of the modification formula. In a case in which a plurality of kinds of 1st branch patterns are generated, the control section 9 generates the common modification parameter involved in at least two 1st branch patterns included in the plurality of kinds of 1st branch patterns. The control section 9 can generate the common modification parameter related to all of the 1st branch patterns, or can group a plurality of 1st branch patterns in accordance with the degree of approximation of the branch parameter, and generate the common balance parameter in units of each group. The branch parameter is, for example, the number of branches, the output ratio (output target value), the amount of vertical branching, the amount of individual aberration correction, and the like. In a case in which the number of branches is the branch parameter, the control section 9 can group the 1st branch patterns in accordance with the number of branches, and generate the common balance parameter in units of each group. Figure 16 In the example illustrated, the control section 9 groups in accordance with the degree of approximation of the output ratio as the branch parameter, and generates the balance parameter in units of each of the group of the region A, the group of the region B, and the group of the region C.

[0109] In the 5th process, the control section 9 performs a process of modifying the calculation formula with the balance parameter and generating the 2nd branch pattern on the basis of the modified calculation formula, and a process of setting and displaying the 2nd branch pattern in the reflection-type spatial light modulator 34 at the time of the processing process. The control section 9 can also acquire information indicating the branch parameter in the processing process, and modify the calculation formula in accordance with the balance parameter of the group corresponding to the branch parameter. Figure 17 and Figure 18 is a diagram illustrating the use of the balance parameter corresponding to the branch parameter. The control section 9 can also acquire information indicating the number of branches as the information indicating the branch parameter in the processing process in accordance with the information received in the setting screen (refer to Figure 7 and Figure 8 ) of the GUI 111, for example. Figure 17As shown, the balance parameter corresponding to the number of branches is determined, and the calculation formula is corrected based on the determined balance parameter. In Figure 17 The 2-point branch balance parameter is reflected into the calculation formula when the number of branches is 2, the 3-point branch balance parameter is reflected into the calculation formula when the number of branches is 3, and the 4-point branch balance parameter is reflected into the calculation formula when the number of branches is 4.

[0110] The control section 9 can also acquire information indicating the output ratio as information indicating the branch parameter in the machining process based on information received in the setting screen (refer to Figure 7 and Figure 8 ) of the GUI 111, determine the balance parameter corresponding to the output ratio, and correct the calculation formula based on the determined balance parameter. For example, assume that the balance parameters of three regions (region A, region B, region C) corresponding to the output ratio are generated as shown in Figure 16 In this case, as shown in Figure 18 , the control section 9 reflects the balance parameter of region A (balance parameter list A shown in Figure 18 ) into the calculation formula when the output ratio included in region A is set, and reflects the balance parameter of region B (balance parameter list B shown in Figure 18 ) into the calculation formula when the output ratio included in region B is set.

[0111] Next, the generation processing of the branch pattern to which the balance parameter is applied will be described with reference to Figure 19 and Figure 20 . Figure 19 and Figure 20 are flowcharts illustrating the generation processing of the branch pattern to which the balance parameter is applied. In Figure 19 , an example in which one balance parameter is used is shown, and in Figure 20 , an example in which a plurality of balance parameters are switched to be used is shown.

[0112] As shown in Figure 19 , first, the first branch pattern is derived based on information (design value) received in the setting screen of the GUI 111, and the first branch pattern is set / displayed in the reflective spatial light modulator 34 (step S1: first process).

[0113] Next, the laser L1 is emitted to the reflective spatial light modulator 34 on which the first branch pattern is displayed, and the laser irradiation is started by the laser branched into a plurality according to the first branch pattern (step S2: second process).

[0114] Next, the reflected light of the branched light from the object 100 is detected (imaged) by the detection section 17 (step S3: third process).

[0115] Next, based on the imaging data (detection result of reflected light), an output measured value of each of the branched lasers is derived, and based on an error of the output measured value from an expected output ratio (output target value, design value), a balancing parameter is generated (step S4: 4th process).

[0116] Finally, a 2nd branched pattern is generated based on the corrected calculation formula, and the generated 2nd branched pattern is set / displayed on the reflective spatial light modulator 34 for the machining process (step S5: 5th process).

[0117] Next, the effect of the laser machining device 1 of the present embodiment will be described. Figure 20 An example in which a plurality of balancing parameters are switched will be described. As shown in FIG. 9, the processes of steps Sll to S14 are the same as the processes of steps S1 to S4 of FIG. 8. Figure 20 Figure 19 However, in step S14, a plurality of 1st branched patterns are grouped in accordance with the degree of approximation of the branching parameters, and a balancing parameter is generated for each group.

[0118] Then, information indicating the branching parameters in the machining process (machining conditions) is acquired, and the balancing parameter is switched based on the machining conditions (for example, output ratio) (step S15). That is, a balancing parameter that matches the machining conditions is selected from among the plurality of balancing parameters.

[0119] Finally, the calculation formula is corrected based on the selected balancing parameter, a 2nd branched pattern is generated based on the corrected calculation formula, and the generated 2nd branched pattern is set / displayed on the reflective spatial light modulator 34 for the machining process.

[0120] Next, the effect of the laser machining device 1 of the present embodiment will be described.

[0121] ​The laser processing apparatus 1 of the present embodiment is a laser processing apparatus that forms 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 reflection-type spatial light modulator 34 that modulates the laser light emitted from the light source unit 8, a detection unit 17 that detects reflected light of the laser light from the object 100, and a control unit 9 configured to execute: a first process of generating, based on a prescribed calculation formula, a first branch pattern that is a branch pattern that branches the laser light into a plurality of pieces, and that corresponds to an output target value of each of the branched laser lights, and setting and displaying the generated first branch pattern in the reflection-type spatial light modulator 34; a second process of controlling the light source unit 8 so as to emit the laser light in a state in which the first branch pattern is displayed in the reflection-type spatial light modulator 34; a third process of controlling the detection unit 17 so as to detect the reflected light of each of the branched laser lights using the first branch pattern; a fourth process of deriving, based on a detection result of the detection unit 17, an output measured value of each of the branched laser lights, and generating a correction parameter that corrects the calculation formula, that is, a balance parameter involved in generation of a second branch pattern that is a branch pattern that causes the output measured value to approach the output target value; and a fifth process of correcting the calculation formula according to the balance parameter, and generating the second branch pattern based on the corrected calculation formula, and setting and displaying the generated second branch pattern in the reflection-type spatial light modulator 34 for use in a processing procedure.

[0122] In the laser processing apparatus 1 of the present embodiment, the laser light is emitted in a state in which the first branch pattern generated based on the output target value of each of the branched laser lights is displayed in the reflection-type spatial light modulator 34, and the reflected light from the object 100 is detected, and the output measured value of each of the laser lights is derived based on the detection result. Then, in the present laser processing apparatus 1, the balance parameter involved in generation of the second branch pattern that causes the output measured value to approach the output target value is generated, the second branch pattern is generated by the calculation formula corrected by the balance parameter, and the second branch pattern is displayed in the reflection-type spatial light modulator 34 for use in the processing procedure. According to such a configuration, the balance parameter for generating the second branch pattern that causes the output measured value that is estimated with high precision based on the actually detected reflected light to approach the output target value is generated. Then, at the time of the processing procedure, the calculation formula is corrected by the balance parameter, and the second branch pattern that can cause the output of the branched light to approach the output target value more than the first branch parameter is generated, and thus it is possible to appropriately adjust the output of the branched light to a desired value. As described above, according to the laser processing apparatus 1 of the present embodiment, it is possible to adjust the output of the branched light to a desired value, and to improve the processing quality.

[0123] The control section 9 can also generate, in the first process, a plurality of first branch patterns in which the combinations of the output target values of the respective lasers after branching are different from each other, and generate, in the fourth process, a common balance parameter related to at least two first branch patterns included in the plurality of first branch patterns. In this way, by generating a common balance parameter for a plurality of first branch patterns in which the conditions of the output target values are different from each other, it is possible to generate unique second branch patterns using the same balance parameter, and it is possible to facilitate the generation and management of the balance parameter compared to a case in which a balance parameter is generated for each first branch pattern.

[0124] The control section 9 can also group, in the fourth process, the plurality of first branch patterns in accordance with the degree of approximation of the balance parameters, and generate a common balance parameter for each group. For example, in a case in which a common one balance parameter is generated for all of the first branch patterns, in a case in which the first branch patterns included in the group differ greatly from each other in the branching parameters, and the like, it is not possible to sufficiently improve the accuracy of all of the second branch patterns (the accuracy of causing the outputs of the branched lights to approximate the output target values) by correcting the calculation formula using the generated common balance parameter. In this regard, by generating a common balance parameter for a group in which the branching parameters are approximate, and generating another balance parameter between groups in which the branching parameters are not approximate, it is possible to ensure the accuracy of the second branch patterns (the accuracy of causing the outputs of the branched lights to approximate the output target values).

[0125] The control section 9 can also group, in the fourth process, the plurality of first branch patterns in accordance with the degree of approximation of the output target values as the branching parameters. By doing so, a common balance parameter is generated for a group in which the output target values are approximate, and it is possible to ensure the accuracy of the second branch patterns (the accuracy of causing the outputs of the branched lights to approximate the output target values).

[0126] The control section 9 can also acquire, in the fifth process, information indicating the branching parameters in the machining process, and correct the calculation formula using the balance parameter of the group corresponding to the branching parameters. By doing so, it is possible to perform the machining process using the second branch patterns generated by the calculation formula corrected using the balance parameter appropriate for the branching parameters in the machining process, and it is possible to improve the machining quality.

[0127] The control section 9 can also generate, in the first process, a first branch pattern in which the laser is branched to different positions in the vertical direction of the thickness direction of the object 100. In actual machining, there are cases in which the laser is branched to different positions in the vertical direction (longitudinal branching), and by generating a first branch pattern related to this longitudinal branching, it is possible to generate a balance parameter related to the generation of a second branch pattern that can cause the outputs of the branched lights in the case of longitudinal branching to appropriately approximate the output target values.

[0128] The above describes the embodiments, but the present application is not limited to the above-described embodiments. For example, regarding the generation of the balance parameter (the correction parameter), as a method of measuring the output of each laser after branching, the method of detecting the reflected light from the object by the detection section is described, but is not limited thereto. Specifically, the output of each laser after branching involved in the generation of the balance parameter can also be measured with a power meter. Hereinafter, the case where the balance parameter is generated using a power meter will be described with reference to Figure 21 and Figure 22 The case where the balance parameter is generated using a power meter will be described.

[0129] Figure 21 is a schematic configuration diagram of a laser processing device 500 which is a modification example. As shown in Figure 21 , the laser processing device 500 is provided with 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 device 500 is a device which forms a modified region on an object by condensing laser light L on the object. Here, for example, a scenario where the balance parameter is generated at the time of manufacturing or adjustment of the laser processing device 500 is assumed, and an object as a processing target is not provided on a stage (not shown). Then, a power meter 700 for measuring laser intensity is provided below the condensing optical system 404 (for example, placed on the stage (not shown)), and the balance parameter is generated based on the output measurement result of the laser by the power meter 700 (details will be described later).

[0130] The laser light source 402 is fixed to the top plate 436 of the housing 431 with a screw or the like so as to emit 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 it to the obliquely upward direction with respect to the horizontal direction.

[0131] The 4f optical system 441 adjusts the wavefront shape of the laser light L modulated by the reflective spatial light modulator 403, and has a first lens 441a and a second lens 441b. The first lens 441a and the second lens 441b are arranged on the optical path between the reflective spatial light modulator 403 and the condensing optical system 404 in such a manner that the distance of the optical path between the reflective spatial light modulator 403 and the first lens 441a becomes a first focal length of the first lens 441a, the distance of the optical path between the condensing optical system 404 and the second lens 441b becomes a second focal length of the second lens 441b, and the distance of the optical path between the first lens 441a and the second lens 441b becomes the sum of the first focal length and the second focal length, and the first lens 441a and the second lens 441b become a biaxial telecentric optical system. According to this 4f optical system 441, it is possible to suppress the wavefront shape change and the increase in aberration of the laser light L modulated by the reflective spatial light modulator 403 due to spatial propagation.

[0132] The light shield 420 is a light barrier member having an opening 420a through which the first processed light and the second processed light described below pass. The light shield 420 is disposed on the Fourier plane (i.e., the plane containing the confocal point O) between the first lens 441a and the second lens 441b. As described later, the range of the laser light L shielded by the light shield 420 is changed, and the output measurement of the branched light is performed using the power meter 700. In addition, the position at which the light shield 420 cuts the laser light L can not necessarily be the position at which the condensing point is most reduced, but can be a position in the vicinity of the Fourier plane.

[0133] 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 to the power meter 700. The condensing optical system 404 is configured to include a plurality of lenses and is disposed on the bottom plate 433 of the housing 431 via a driving unit 432 configured to include a piezoelectric element or the like.

[0134] In the laser processing apparatus 500 configured as described above, the laser light L emitted from the laser light source 402 travels in the horizontal direction within the housing 431, is reflected downward by the mirror 405a, and the light intensity is adjusted by the attenuator 407. Then, the laser light L is reflected in the horizontal direction by the mirror 405b, the intensity distribution of the laser light L is homogenized by the beam homogenizer 460, and is incident on the reflective spatial light modulator 403.

[0135] The laser light L incident on the reflective spatial light modulator 403 is transmitted through the branch pattern as a modulation pattern displayed on the liquid crystal layer, and is thereby modulated (branched) in accordance with the modulation pattern. Such a modulation pattern (branch pattern) is generated by the control section 450 in accordance with the output target value of each laser light after branching. Each laser light after branching is then reflected upward by the mirror 406a, the polarization direction is changed by the λ / 2 wavelength plate 428, is reflected in the horizontal direction by the mirror 406b, and is incident on the 4f optical system 441.

[0136] The 4f adjusts the wavefront shape 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 laser light L after branching is transmitted through the first lens 441a, is condensed, is reflected downward by the mirror 419, is diverged through the confocal point O, and is again condensed into parallel light by the second lens 441b. Then, the laser light L is transmitted through the dichroic mirror 410, 438 in this order, and is incident on the condensing optical system 404, which condenses the laser light L to the power meter 700.

[0137] Further, the laser processing apparatus 500 can also be provided, inside the housing 431, with a surface observation unit 411 for observing a laser incidence surface with respect to an object, and an AF (Auto Focus) unit 412 for finely adjusting the distance of the condensing optical system 404 from the object. The surface observation unit 411 has an observation light source 411a and a detector 411b.

[0138] The laser processing apparatus 500 thus includes a control section 450 composed of a CPU, a ROM, a RAM, and the like, as a means for controlling the laser processing apparatus 500. The control section 450 controls the laser light source 402, adjusting the output, the pulse width, and the like of the laser light L emitted from the laser light source 402. Further, the control section 450 controls the position of the housing 431, a worktable (not shown), and the driving of the driving unit 432.

[0139] Further, the control section 450 applies a prescribed voltage to each pixel electrode in the reflective spatial light modulator 403, causing the liquid crystal layer to display a prescribed modulation pattern (branching pattern), thereby causing the laser light L to be desirably modulated (branched) 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 section 450. The modulation pattern includes an individual difference correction pattern for correcting individual differences (e.g., distortion occurring in the liquid crystal layer of the reflective spatial light modulator 403) occurring in the laser processing apparatus 500, a spherical aberration correction pattern for correcting spherical aberration, and the like.

[0140] The laser processing method implemented in the laser processing apparatus 500 configured as above includes: a first step of generating, based on a prescribed calculation algorithm, a first branching pattern corresponding to an output target value of each laser light branched into a plurality, as a branching pattern for branching the laser light into a plurality, and setting and displaying the generated first branching pattern in the reflective spatial light modulator 403; a second step of emitting laser light to the reflective spatial light modulator 403 on which the first branching pattern is displayed, and measuring the output of the laser light branched into a plurality by the first branching pattern using the power meter 700, thereby deriving an output measured value of each laser light branched; and a third step of generating and outputting a correction parameter for correcting the calculation algorithm, i.e., a balance parameter involved in the generation of a second branching pattern that is a branching pattern for bringing the output measured value close to the output target value. In the second step, a light-shielding time output measurement process of performing output measurement using the power meter 700 while shielding a part of each laser light branched using the light shield 420 is implemented, and in the light-shielding time output measurement process, output measurement is performed using the power meter 700 while changing the range of the laser light shielded by the light shield 420.

[0141] Figure 22 is a graph illustrating the output of each laser light branched derived using the power meter 700. Figure 22(a) represents the branch light from the reflective spatial light modulator 403 to the power meter 700. Figure 22 (b) indicates the position of the light-shielding plate 420 located on the Fourier surface (i.e., the surface containing the confocal point O).

[0142] like Figure 22 As shown in (a), the laser light passing through the first branching pattern displayed on the liquid crystal layer of the reflective spatial light modulator 403 is branched into multiple (here, three) lasers by the first branching pattern. Each branched laser light reaches the Fourier surface (including the confocal point O) via the first lens 441a. A light-shielding plate 420 is provided on the Fourier surface. Then, the laser light diverging after passing through the confocal point O passes through the second lens 441b and is focused by the focusing optical system 404 onto the power meter 700, where the output is measured (output measurement processing is performed when the light is shielded).

[0143] Here, in the output measurement processing during shading, the position of the shading plate 420 set on the Fourier surface is continuously varied. For example, as Figure 22 As shown in (b), in the initial step (STEP1) of the output measurement processing during shading, a light-shielding plate 420 is positioned where none of the branched lasers (-1, 0, 1) are shaded. In this case, the power meter 700 measures output data P1 containing the outputs of all lasers (-1, 0, 1). In the next step (STEP2), the light-shielding plate 420 is positioned where only one of the branched lasers (-1, 0, 1) is shaded. In this case, the power meter 700 measures output data P2 containing the outputs of two lasers (-1, 0). In the final step (STEP3), the light-shielding plate 420 is positioned where the 0 and 1 lasers of the branched lasers (-1, 0, 1) are shaded. In this case, the power meter 700 measures output data P3 containing the output of one laser (-1).

[0144] In this way, while partially blocking the laser with the light-shielding plate 420, measurements are performed based on the power meter 700. Thus, the output ratio of the -1 laser (-1, 0, and 1) is P3 / P1, the output ratio of the 0 laser is (P2-P3) / P1, and the output ratio of the +1 laser is (P1-P2) / P1. Therefore, the measured output values ​​of each branched laser can be derived. Furthermore, the configuration change of the light-shielding plate 420 can be performed manually or automatically under the control of the control unit 450.

[0145] According to such a laser processing method, in a state where the first split pattern set in accordance with the output target value of each laser after splitting is set to the reflection-type spatial light modulator 403, the laser is emitted, the laser split into a plurality by the first split pattern is measured by the power meter 700, and the output measured value of each laser after splitting is derived based on the measurement result. Thus, in the present laser processing method, the balance parameter involved in the generation of the second split pattern that brings the output measured value close to the output target value is generated and output. According to such a configuration, the balance parameter for generating the second split pattern that brings 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 is brought close to the target value, the calculation algorithm is corrected using the balance parameter at the time of processing, and the second split pattern that brings the output of the split light closer to the output target value than the first split pattern is generated, whereby it is possible to appropriately adjust the output of the split light to the desired value. As described above, according to the present laser processing method, it is possible to adjust the output of the split light to the desired value, and improve the processing quality.

[0146] In addition, in the second process, a light-shielding time output measurement process in which the output is measured by the power meter 700 while a part of each laser after splitting is shielded by the light shield 420 is performed, and in the light-shielding time output measurement process, the range of the laser shielded by the light shield 420 is changed while the output is measured by the power meter 700. In this way, by changing the range of the laser shielded by the light shield 420 while the output is measured by the power meter 700, it is possible to appropriately derive the output of each laser after splitting.

Claims

1. A laser processing apparatus, characterized in that, It is a laser processing device that forms a modified region on an object by irradiating the object with a laser. include: The light source from which the laser is emitted; A spatial light modulator that modulates the laser emitted from the light source; A detection unit that detects the reflected light of the laser from the object; and Control Department The control unit is configured to execute: The first process, based on a prescribed calculation algorithm, generates a first branch pattern corresponding to the output target value of each laser after branching, which is a branch pattern that makes the laser branch into multiple branches. The generated first branch pattern is set and displayed in the spatial light modulator. The second process controls the light source to emit the laser while the first branch pattern is displayed on the spatial light modulator; The third process controls the detection unit in a manner that detects the reflected light of each laser after branching using the first branch pattern; The fourth process involves deriving the measured output values ​​of each laser after branching based on the detection results of the detection unit, generating correction parameters for the generation of a second branch pattern that corrects the calculation algorithm and serves as a branch pattern to make the measured output values ​​closer to the target output value; and The fifth process involves correcting the calculation algorithm using the correction parameters, generating the second branch pattern based on the corrected calculation algorithm, and setting and displaying the generated second branch pattern on the spatial light modulator for use in the processing technology.

2. The laser processing apparatus as described in claim 1, characterized in that, The control unit, In the first process, multiple first branch patterns are generated, each with a different combination of the target output values ​​of the branched lasers. In the fourth process, at least two of the first branch patterns contained in the plurality of first branch patterns are generated to share the common correction parameters.

3. The laser processing apparatus as described in claim 2, characterized in that, In the fourth process, the control unit groups the various first branch patterns according to the approximation of the branch parameters, and generates common correction parameters for each group.

4. The laser processing apparatus as described in claim 3, characterized in that, In the fourth process, the control unit performs grouping corresponding to the approximation of the output target value, which is the branch parameter.

5. The laser processing apparatus as described in claim 3, characterized in that, In the fifth process, the control unit obtains information representing the branch parameters in the processing technology and corrects the calculation algorithm according to the correction parameters of the group corresponding to the branch parameters.

6. The laser processing apparatus as described in claim 4, characterized in that, In the fifth process, the control unit obtains information representing the branch parameters in the processing technology and corrects the calculation algorithm according to the correction parameters of the group corresponding to the branch parameters.

7. The laser processing apparatus according to any one of claims 1 to 6, characterized in that, In the first process, the control unit generates a first branching pattern that branches the laser to different positions in the vertical direction, which is the thickness direction of the object.

8. A laser processing method, characterized in that, This is a laser processing method that forms a modified region on an object by irradiating it with a laser. include: In the first step, based on the prescribed calculation algorithm, a first branch pattern is generated that corresponds to the output target value of each laser after branching, which is a branch pattern that makes the laser branch into multiple branches. The generated first branch pattern is set and displayed in the spatial light modulator. In the second step, a laser is emitted from the spatial light modulator displaying the first branch pattern, and the laser, which is branched into multiple branches according to the first branch pattern, is irradiated onto the object. The third step is to detect the reflected light from the object of each branched laser. In the fourth step, based on the detection results of the reflected light, the measured output values ​​of each laser after branching are derived, and correction parameters are generated for the generation of a second branch pattern that corrects the calculation algorithm and serves as a branch pattern to make the measured output values ​​close to the target output value; and In the fifth step, the calculation algorithm is modified according to the correction parameters. Based on the modified calculation algorithm, the second branch pattern is generated. The generated second branch pattern is set and displayed on the spatial light modulator for use in the processing technology.

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