Laser processing apparatus and laser processing method

Abstract

To simplify a mechanism for adjusting the interval between focal points of laser beams.SOLUTION: A laser processing apparatus 1 comprises: a holding unit 10 that holds a workpiece 200; an oscillator 22 that generates a laser beam 21; a branching element 25 that branches the laser beam 21 generated by the oscillator 22 into a first laser beam 28 and a second laser beam 29; a rotation mechanism 26 that rotates the branching element 25 around an optical axis 251 of the laser beam passing through the center of the branching element 25; and a focusing unit 27 including a focusing lens 271 that focuses the first laser beam 28 branched by the branching element 25 onto the workpiece 200 held by the holding unit 10, and focuses the second laser beam 29 branched by the branching element 25 onto the workpiece 200 held by the holding unit 10.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a laser processing apparatus and a laser processing method. [Background technology]

[0002] In order to improve productivity in laser processing, a laser processing device has been proposed that can simultaneously process multiple planned processing lines on a workpiece by irradiating the multiple planned processing lines with a laser beam at the same time (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-290086 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional processing devices, the configurations of the mechanism for splitting the laser beam and the mechanism for adjusting the intervals between the focal points of each split laser beam are complex, leaving room for improvement.

[0005] An object of the present invention is to provide a laser processing apparatus and a laser processing method that can simplify the mechanism for adjusting the interval between the focal points of a laser beam. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the laser processing apparatus of the present invention is a laser processing apparatus characterized by comprising: a holding unit that holds a workpiece; an oscillator that generates a laser beam; a branching element that branches the laser beam generated by the oscillator into a first laser beam and a second laser beam; a rotation mechanism that rotates the branching element around an axis passing through the center of the branching element; and a focusing unit having a focusing lens that focuses the first laser beam branched by the branching element on the workpiece held by the holding unit and focuses the second laser beam branched by the branching element on the workpiece held by the holding unit.

[0007] In the laser processing device, the branching element may be a diffractive optical element.

[0008] In the laser processing device, the splitting element may be a polarizing prism.

[0009] The laser processing apparatus may include a controller that controls at least the rotation mechanism, the controller including an index value registration unit in which an index value between the focal point position of the first laser beam and the focal point position of the second laser beam is registered, and an angle calculation unit that calculates the rotation angle of the branching element based on the index value registered in the index value registration unit, and the controller may control the rotation mechanism based on the rotation angle calculated by the angle calculation unit.

[0010] In the laser processing device, a plurality of processing lines extending in a first direction may be set on the workpiece, the focal point of the first laser beam may be positioned on the first processing line, and the focal point of the second laser beam may be positioned on a second processing line different from the first processing line.

[0011] In the laser processing device, the focusing unit may form the first laser beam perpendicular to the workpiece and the second laser beam perpendicular to the workpiece.

[0012] A laser processing method of the present invention is a laser processing method for a workpiece on which a plurality of planned processing lines extending in a first direction are set, and includes a holding step of holding the workpiece with a holding unit, and a laser processing step of splitting a laser beam generated by an oscillator into a first laser beam and a second laser beam with a splitting element, and focusing the first laser beam and the second laser beam on the workpiece held by the holding unit with a focusing unit while moving the focusing unit and the holding unit relatively in the first direction to perform laser processing on the workpiece along the planned processing lines, wherein in the laser processing step, the focusing point of the first laser beam is set at a first planned processing line. the focusing point of the second laser beam is positioned on a fixed line, and the focusing point of the second laser beam is positioned on a second planned processing line different from the first planned processing line, and the first laser beam is irradiated along the first planned processing line and the second laser beam is irradiated along the second planned processing line, and at least before performing the laser processing step, the branching element is rotated based on the distance in a second direction orthogonal to the first direction between the focusing point of the first laser beam and the focusing point of the second laser beam to adjust the distance between the focusing point of the first laser beam and the focusing point of the second laser beam. [Effects of the Invention]

[0013] The present invention has an effect of simplifying the mechanism for adjusting the interval between the focal points of the laser beam. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a laser processing device according to the first embodiment. [Figure 2] FIG. 2 is a perspective view showing a workpiece to be processed by the laser processing apparatus shown in FIG. [Figure 3] FIG. 3 is a diagram showing the configuration of a laser beam irradiation unit of the laser processing apparatus shown in FIG. [Figure 4]FIG. 4 is a plan view showing an example of the focal point of the first laser beam and the focal point of the second laser beam of the laser beam irradiation unit shown in FIG. [Figure 5] FIG. 5 is a plan view showing another example of the focal point of the first laser beam and the focal point of the second laser beam of the laser beam irradiation unit shown in FIG. [Figure 6] FIG. 6 is a flowchart showing the flow of the laser processing method according to the first embodiment. [Figure 7] FIG. 7 is a plan view of a workpiece showing an example of the trajectory of the focal point of the first laser beam and the trajectory of the focal point of the second laser beam in the laser processing step of the laser processing method shown in FIG. [Figure 8] FIG. 8 is a diagram showing a modified example of the laser beam irradiation unit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0016] [Embodiment 1] A laser processing apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an example of the configuration of the laser processing apparatus according to the first embodiment. FIG. 2 is a perspective view showing a workpiece to be processed by the laser processing apparatus shown in FIG. 1. FIG. 3 is a view showing the configuration of a laser beam irradiation unit of the laser processing apparatus shown in FIG. 2. FIG. 4 is a plan view showing an example of the focal point of the first laser beam and the focal point of the second laser beam of the laser beam irradiation unit shown in FIG. 3. FIG. 5 is a plan view showing another example of the focal point of the first laser beam and the focal point of the second laser beam of the laser beam irradiation unit shown in FIG. 3.

[0017] (Workpiece) The laser processing apparatus 1 according to the first embodiment shown in Fig. 1 is a processing apparatus that processes a workpiece 200 shown in Fig. 2. The workpiece 200 to be processed by the laser processing apparatus 1 according to the first embodiment shown in Fig. 1 is, for example, a disk-shaped semiconductor wafer having a substrate such as a silicon substrate, a sapphire substrate, a gallium substrate, or a SiC substrate, or a wafer such as an optical device wafer.

[0018] 2, in the workpiece 200, a plurality of devices 203 are formed in an area partitioned by processing lines 202-1 parallel to a first direction 211 that are parallel to each other on a surface 201 and processing lines 202-2 parallel to a second direction 212 that is perpendicular to the first direction 211. In this way, the workpiece 200 is set with a plurality of processing lines 202-1 extending in the first direction 211 and a plurality of processing lines 202-2 extending in the second direction 212. The devices 203 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integrations), image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), or memories (semiconductor memory devices).

[0019] In the first embodiment, the workpiece 200 has a central portion of a tape 205, which has a diameter larger than the workpiece 200 and has an annular frame 206 attached to its outer edge, attached to a back surface 204 behind the front surface 201, and is supported within an opening on the inside of the frame 206. In the present invention, the workpiece 200 is not limited to being attached to the tape 205. In addition, in the present invention, the workpiece 200 does not need to have the lines to be processed 202-1, 202-2 and the device 203 formed on the front surface 201.

[0020] (Laser processing equipment) As shown in FIG. 1, the laser processing apparatus 1 of embodiment 1 includes a holding unit 10, a moving unit 30, a laser beam irradiation unit 20, an imaging unit (not shown), a cleaning unit 40, a transport unit 50, and a controller 100.

[0021] The holding unit 10 is disk-shaped, and has a flat holding surface 11 formed of porous ceramic or the like along the horizontal direction for holding the workpiece 200. The holding unit 10 is also provided so as to be movable by a moving unit 30 between a processing area below the laser beam irradiation unit 20 and a carry-in / out area spaced from below the laser beam irradiation unit 20 where the workpiece 200 is carried in and out.

[0022] The holding unit 10 is connected to a vacuum suction source (not shown), and is sucked by the vacuum suction source to suck and hold the workpiece 200 placed on the holding surface 11. In the first embodiment, the holding unit 10 sucks and holds the back surface 204 of the workpiece 200 via tape 205. Also, as shown in FIG. 1, a plurality of clamping portions 12 that clamp a frame 206 are provided around the periphery of the holding unit 10.

[0023] The moving unit 30 moves the holding unit 10 and the laser beam irradiation unit 20 relatively. The moving unit 30 includes at least a Y-axis moving unit 31, which is an indexing feed unit that moves the holding unit 10 in the Y-axis direction parallel to the horizontal direction, an X-axis moving unit 32, which is a processing feed unit that moves the holding unit 10 in the X-axis direction that is parallel to the horizontal direction and perpendicular to the Y-axis direction, and a rotational moving unit 33 that rotates the holding unit 10 around an axis parallel to the Z-axis direction that is parallel to the vertical direction.

[0024] The Y-axis movement unit 31 is installed on the apparatus main body 2, and moves the moving plate 3 on which the X-axis movement unit 32 is installed in the Y-axis direction, thereby moving the holding unit 10 in the Y-axis direction. The X-axis movement unit 32 is installed on the moving plate 3, and moves the second moving plate 4 on which the rotational movement unit 33 is installed in the X-axis direction, thereby moving the holding unit 10 in the X-axis direction. The rotational movement unit 33 is installed on the second moving plate 4, and supports the holding unit 10, thereby rotating the holding unit 10 around its axis.

[0025] The Y-axis moving unit 31 moves each moving plate 3, the X-axis moving unit 32, the second moving plate 4, the rotational moving unit 33, and the holding unit 10 in the Y-axis direction. The X-axis moving unit 32 moves each second moving plate 4, the rotational moving unit 33, and the holding unit 10 in the X-axis direction.

[0026] The Y-axis moving unit 31 and the X-axis moving unit 32 each include a well-known ball screw rotatably mounted around its axis, a well-known motor for rotating the ball screw around its axis, and a well-known guide rail for supporting the moving plates 3 and 4 so that they can move in the X-axis or Y-axis direction. The rotational moving unit 33 includes a well-known motor for rotating the holding unit 10 around its axis.

[0027] 1, the laser beam irradiation unit 20 is provided at a portion on the tip of a support column 6 whose base end is supported on an erect wall 5 erected from the end of the device body 2 in the Y-axis direction. The laser beam irradiation unit 20 irradiates laser beams 28, 29 (shown in FIG. 3) onto the workpiece 200 held by the holding unit 10 to perform laser processing.

[0028] 3, the laser beam irradiation unit 20 includes an oscillator 22, a repetition frequency setting unit 23, an output adjustment unit 24, a branching element 25, a rotation mechanism 26, and a focusing unit 27. The oscillator 22 is a device that generates and oscillates a pulsed laser beam 21 having a wavelength that is absorbed by the workpiece 200. In the first embodiment, the laser beam 21 has a wavelength that is absorbed by the workpiece 200, but in the present invention, the laser beam 21 may have a wavelength that is transparent to the workpiece 200. The repetition frequency setting unit 23 sets the repetition frequency of the pulsed laser beam 21 oscillated by the oscillator 22.

[0029] The output adjustment unit 24 adjusts the output of the laser beam 21 oscillated by the oscillator 22. In the first embodiment, the output adjustment unit 24 is a well-known attenuator. The branching element 25 branches the laser beam 21 generated and oscillated by the oscillator 22 into a first laser beam 28 and a second laser beam 29. In the first embodiment, the branching element 25 branches the laser beam 21 so that the first laser beam 28 and the second laser beam 29 are aligned in the Y-axis direction. In the first embodiment, the branching element 25 is made of a diffractive optical element (DOE) that branches the single laser beam 21 into two laser beams, the first laser beam 28 and the second laser beam 29.

[0030] The rotation mechanism 26 rotates the branching element 25 around an optical axis 251 of the laser beam 21 incident on the branching element 25, which is an axis passing through the center of the branching element 25. In the first embodiment, the rotation mechanism 26 includes a motor or the like that rotates the branching element 25 around the optical axis 251.

[0031] The focusing unit 27 has a focusing lens 271 that focuses the first laser beam 28 branched by the branching element 25 onto the workpiece 200 held by the holding unit 10, and focuses the second laser beam 29 branched by the branching element 25 onto the workpiece 200 held by the holding unit 10. In the first embodiment, the focusing lens 271 is a so-called biconvex lens. In addition, in embodiment 1, the focusing unit 27 has, in addition to the focusing lens 271 which is a biconvex lens, a pair of well-known concave-convex lenses with their convex surfaces facing each other and with the focusing lens 271 positioned between them, a concave-convex lens positioned between the concave-convex lens on the holding unit 10 side and the focusing lens 271 with its concave surface facing the focusing lens 271, and a plano-convex lens positioned between this concave-convex lens and the concave-convex lens on the holding unit 10 side and with its convex surface facing the focusing lens 271, and forms a first laser beam 28 perpendicular to the surface 201 of the workpiece 200 and forms a second laser beam 29 perpendicular to the surface 201 of the workpiece 200.

[0032] In the laser beam irradiation unit 20, the focal point 281 of the first laser beam 28 formed by the focusing unit 27 and the focal point 291 of the second laser beam 29 are aligned in the Y-axis direction as shown in Figures 3 and 4. In addition, in the laser beam irradiation unit 20, the rotation mechanism 26 rotates the branching element 25 around the optical axis 251, thereby changing the interval 220 in the Y-axis direction between the focal point 281 of the first laser beam 28 and the focal point 291 of the second laser beam 29 formed by the focusing unit 27, as shown in Figures 4 and 5. In other words, the interval 220 changes depending on the direction θ, which is the rotation angle of the branching element 25 around the optical axis 251.

[0033] The imaging unit includes an imaging element that images an area to be divided of the workpiece 200 held in the holding unit 10 before laser processing. The imaging element is, for example, a CCD (Charge-Coupled Device) imaging element or a CMOS (Complementary MOS) imaging element. The imaging unit images the workpiece 200 held in the holding unit 10 to obtain an image for performing alignment between the workpiece 200 and the laser beam irradiation unit 20, and outputs the obtained image to the controller 100.

[0034] Cleaning unit 40 cleans workpiece 200 after laser processing. Cleaning unit 40 is disc-shaped and includes spinner table 41, which has a flat holding surface formed of porous ceramic or the like along the horizontal direction for holding workpiece 200, and cleaning nozzle 42. Spinner table 41 is rotated around an axis parallel to the Z-axis direction by a rotary drive source (not shown).

[0035] The holding surface of spinner table 41 is connected to a vacuum suction source (not shown), and is sucked by the vacuum suction source to suck and hold workpiece 200 placed on the holding surface. In the first embodiment, spinner table 41 sucks and holds back surface 204 of workpiece 200 via tape 205. In addition, a plurality of clamps 43 that clamp frame 206 are provided around spinner table 41.

[0036] The cleaning nozzle 42 supplies cleaning water (pure water in the first embodiment) to the surface 201 of the workpiece 200 held by the spinner table 41 to clean the surface 201 of the workpiece 200.

[0037] The transport unit 50 transports the workpiece 200 between the holding unit 10 and the cleaning unit 40. The transport unit 50 includes a transport arm 51 that transports the workpiece 200 between the holding unit 10 and the cleaning unit 40.

[0038] The controller 100 controls each component of the laser processing apparatus 1 to cause the laser processing apparatus 1 to perform a processing operation on the workpiece 200. That is, the controller 100 controls at least the rotation mechanism 26. The controller 100 is a computer having an arithmetic processing device with a microprocessor such as a CPU (central processing unit), a storage device with memory such as a ROM (read only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing device of the controller 100 performs arithmetic processing in accordance with a computer program stored in the storage device, and outputs control signals for controlling the laser processing apparatus 1 to each component of the laser processing apparatus 1 via the input / output interface device.

[0039] The controller 100 is connected to a display unit (not shown) configured with a liquid crystal display device or the like that displays the status of the machining operation, images, etc., and an input unit (not shown) that the operator uses to register machining content information, etc. The input unit is configured with at least one of a touch panel provided on the display unit and an external input device such as a keyboard.

[0040] 1, the controller 100 includes a processing control unit 101, an index value registration unit 102, an information storage unit 103, and an angle calculation unit 104. The processing control unit 101 controls each component of the laser processing device 1 to cause the laser processing device 1 to perform processing operations on the workpiece 200.

[0041] The index value registration unit 102 registers an index value 213. The index value 213 is the distance in the Y-axis direction between the position of a focal point 281 of the first laser beam 28 focused on the surface 201 of the workpiece 200 and the position of a focal point 292 of the second laser beam 29 focused on the surface 201 of the workpiece 200, and in the first embodiment, is the distance in the Y-axis direction between the focal points 281 and 291 on the surface 201 of the adjacent processing lines 202-1 and 202-2.

[0042] The information storage unit 103 stores information 105. The information 105 indicates the relationship between the direction θ (corresponding to the rotation angle) of the branching element 25 around the optical axis 251 and the interval 220 in the Y-axis direction between the light-collecting points 281 and 291. The angle calculation unit 104 calculates the direction θ of the branching element 25 around the optical axis 251 based on the index value 213 registered in the index value registration unit 102 and the information 105 stored in the information storage unit 103.

[0043] The functions of the index value registration unit 102 and the information storage unit 103 are realized by a storage device. The functions of the machining control unit 101 and the angle calculation unit 104 are realized by an arithmetic processing unit that performs arithmetic processing in accordance with a computer program stored in the storage device.

[0044] (Laser processing method) Next, a description will be given of a laser processing method according to embodiment 1. Fig. 6 is a flowchart showing the flow of the laser processing method according to embodiment 1. Fig. 7 is a plan view of a workpiece showing an example of the trajectory of the focal point of the first laser beam and the trajectory of the focal point of the second laser beam in the laser processing step of the laser processing method shown in Fig. 6.

[0045] The laser processing method is a method for laser processing a workpiece 200. As shown in Fig. 6, the laser processing method includes a holding step 1001, a focusing point distance adjusting step 1002, a laser processing step 1003, and a cleaning step 1004.

[0046] (holding step) The holding step 1001 is a step in which the workpiece 200 is held by the holding unit 10. In the holding step 1001, the laser processing apparatus 1 starts the processing operation, i.e., the holding step 1001, when the processing conditions are registered in the controller 100 by an operator or the like, the workpiece 200 is placed on the holding surface 11 of the holding unit 10 via the tape 205, and the controller 100 receives an instruction to start the processing operation from the operator or the like. The processing conditions include the index value 213 and the like.

[0047] In the holding step 1001, in the laser processing apparatus 1 of embodiment 1, the processing control unit 101 of the controller 100 suction-holds the back surface 204 of the workpiece 200 to the holding surface 11 of the holding unit 10 via tape 205, and clamps the frame 206 with the clamping section 12.

[0048] (Focus point interval adjustment step) The focal point interval adjustment step 1002 is a step of adjusting the interval 220 between the focal point 281 of the first laser beam 28 and the focal point 291 of the second laser beam 29 by rotating the branching element 25 based on an index value 213, which is the distance in a second direction 212 perpendicular to the first direction 211, between the focal point 281 of the first laser beam 28 and the focal point 291 of the second laser beam 29, at least before performing the laser processing step 1003.

[0049] In the first embodiment, in the focal point interval adjustment step 1002, the angle calculation unit 104 of the controller 100 of the laser processing apparatus 1 calculates the orientation θ of the branching element 25 about the optical axis 251 based on the index value 213 registered in the index value registration unit 102 and the information 105 stored in the information storage unit 103. In the first embodiment, in the focal point interval adjustment step 1002, the process control unit 101 of the controller 100 controls the rotation mechanism 26 to rotate the branching element 25 about the optical axis 251 so that the orientation θ about the optical axis 251 is the orientation θ calculated by the angle calculation unit 104, thereby setting the orientation θ of the branching element 25 to the orientation θ calculated by the angle calculation unit 104. In this way, in the focal point interval adjustment step 1002, the process control unit 101 of the controller 100 controls the rotation mechanism 26 based on the orientation θ calculated by the angle calculation unit 104.

[0050] (Laser processing step) The laser processing step 1003 is a step in which the laser beam 21 generated by the oscillator 22 is split by the splitter element 25 into a first laser beam 28 and a second laser beam 29, and the first laser beam 28 and the second laser beam 29 are focused by the focusing unit 27 onto the workpiece 200 held by the holding unit 10, while the focusing unit 27 and the holding unit 10 are moved relatively in the first direction 211 to perform laser processing on the workpiece 200 along the to-be-processed lines 202-1, 202-2. In the first embodiment, in the laser processing step 1003, the processing control unit 101 of the controller 100 controls the moving unit 30 to move the holding unit 10 toward the processing area, the imaging unit captures an image of the workpiece 200, and performs alignment based on the image captured by the imaging unit.

[0051] In the first embodiment, during alignment, the machining control unit 101 of the controller 100 adjusts the orientation of the holding unit 10 around its axis using the rotational movement unit 33 so that the first direction 211 of the workpiece 200 is parallel to the X-axis direction. Also, in the first embodiment, during alignment, the machining control unit 101 of the controller 100 controls the movement unit 30, the focusing unit 27, etc. to set the focal point 281 of the first laser beam 28, which is obtained by splitting the laser beam 21 using the splitter element 25, on the surface 201 of one of the multiple to-be-processed lines 202-1 extending in the first direction 211, and also sets the focal point 291 of the second laser beam 29 on the surface 201 of the to-be-processed line 202-1 adjacent to the to-be-processed line 202-1 on which the focal point 281 of the first laser beam 28 is set.

[0052] In embodiment 1, in the laser processing step 1003, the laser processing apparatus 1 has the processing control unit 101 of the controller 100 control the laser beam irradiation unit 20 and the moving unit 30, etc., to move the focusing unit 27 and the holding unit 10 of the laser beam irradiation unit 20 relatively in the X-axis direction, i.e., the first direction 211, while setting the focusing points 281, 291 of the laser beams 28, 29 on the surface 201 of the adjacent processing lines 202-1 of the workpiece 200, and irradiating the laser beams 28, 29 onto the surface 201 of the two adjacent processing lines 202-1 extending in the first direction 211 of the workpiece 200. Thus, in embodiment 1, in the laser processing step 1003, the focal point 281 of the first laser beam 28 and the focal point 291 of the second laser beam 29 move on the surface 201 of two adjacent processing lines 202-1 among the multiple processing lines 202-1 extending in the first direction 211, as shown in Figure 7.

[0053] In embodiment 1, in the laser processing step 1003, the laser processing apparatus 1 irradiates the laser beams 28, 29 onto the surface 201 of two adjacent processing lines 202-1 among the multiple processing lines 202-1 extending in the first direction 211 to perform ablation processing, and then the processing control unit 101 of the controller 100 moves the focusing unit 27 of the laser beam irradiation unit 20 and the workpiece 200 held in the holding unit 10 relatively in the Y-axis direction a distance twice the index value 213 (hereinafter referred to as index feed), and irradiates the laser beams 28, 29 onto the surface 201 of the next two adjacent processing lines 202-1 extending in the first direction 211 of the workpiece 200.

[0054] Thus, in the first embodiment, in the laser processing step 1003, the processing control unit 101 of the controller 100 repeats the irradiation of the laser beams 28, 29 onto the surface 201 of two adjacent processing lines 202-1 extending in the first direction 211 and the index feed, thereby irradiating the laser beams 28, 29 onto all of the processing lines 202-1 extending in the first direction 211 of the workpiece 200. Also, in the first embodiment, in the laser processing step 1003, after irradiating all of the processing lines 202-1 extending in the first direction 211 of the workpiece 200 with the laser beams 28, 29, the processing control unit 101 of the controller 100 controls the moving unit 30 to rotate the holding unit 10 90 degrees around the axis, and irradiates the laser beams 28, 29 onto the processing line 202-3 extending in the second direction 212 in the same way as the processing line 202-1 extending in the first direction 211. In the first embodiment, in the laser processing step 1003, the laser processing device 1 irradiates the laser beams 28, 29 onto all the lines to be processed 202-1, 202-2 of the workpiece 200 held by the holding unit 10 to form laser-processed grooves (not shown).

[0055] In the following description, one of the to-be-processed lines 202-1, 202-2 that are simultaneously irradiated with the laser beams 28, 29 in the laser processing step 1003 will be referred to as the first to-be-processed line, and the other will be referred to as the second to-be-processed line. For this reason, in the first embodiment, in the laser processing step 1003, the focal point 281 of the first laser beam 28 is positioned on the first to-be-processed line 202-1, 202-2, and the focal point 291 of the second laser beam 29 is positioned on the second to-be-processed line 202-1, 202-2 that is different from the first to-be-processed lines 202-1, 202-2, and the first laser beam 28 is irradiated along the first to-be-processed lines 202-1, 202-2, and the second laser beam 29 is irradiated along the second to-be-processed lines 202-1, 202-2.

[0056] (Washing step) The cleaning step 1004 is a step for cleaning the surface 201 of the workpiece 200. In the cleaning step 1004, the laser processing apparatus 1 controls the processing control unit 101 of the controller 100 to control the moving unit 30 and the like to move the holding unit 10 to the loading / unloading area, stops suction holding of the holding surface 11 of the holding unit 10 in the loading / unloading area, and stops clamping of the frame 206 of the clamping unit 12.

[0057] In cleaning step 1004, in the laser processing apparatus 1, the processing control unit 101 of the controller 100 controls the transport unit 50 to place the workpiece 200 from the holding unit 10 on the holding surface of the spinner table 41 of the cleaning unit 40. In cleaning step 1004, in the laser processing apparatus 1 according to the first embodiment, the processing control unit 101 of the controller 100 suction-holds the back surface 204 of the workpiece 200 on the holding surface of the spinner table 41 via the tape 205, clamps the frame 206 with the clamp unit 43, rotates the spinner table 41 about its axis, and drops liquid cleaning water from the cleaning nozzle 42 onto the center of the front surface 201 of the workpiece 200.

[0058] The dropped cleaning water flows from the center toward the outer periphery on surface 201 of workpiece 200 due to centrifugal force generated by the rotation of spinner table 41, cleaning surface 201 of workpiece 200. In cleaning step 1004, laser processing apparatus 1 according to embodiment 1 supplies cleaning water for a predetermined time while rotating spinner table 41 about its axis, thereby cleaning surface 201 of workpiece 200.

[0059] As described above, the laser processing apparatus 1 and the laser processing method according to the first embodiment include the branching element 25 that branches the laser beam 21 generated by the oscillator 22, and the rotation mechanism 26 that rotates the branching element 25 around the optical axis 251 that passes through the center of the branching element 25. Therefore, the laser processing apparatus 1 and the laser processing method according to the first embodiment can change the interval 220 between the focal points 281, 291 of the branched laser beams 28, 29 by rotating the branching element 25 around the optical axis 251 with the rotation mechanism 26.

[0060] As a result, the laser processing apparatus 1 and the laser processing method according to the first embodiment can adjust the distance 220 between the focal points 281, 291 of the laser beams 28, 29 by using a simple mechanism, that is, the rotation mechanism 26 that rotates the branching element 25 around the optical axis 251, thereby achieving the effect of simplifying the mechanism for adjusting the distance 220 between the focal points 281, 291 of the laser beams 28, 29.

[0061] The present invention is not limited to the above-described embodiment. In other words, various modifications can be made without departing from the gist of the present invention. In the present invention, the splitting element 25-1 is not limited to a diffractive optical element. For example, as shown in FIG. 8, it may be a polarizing prism, such as a Rochon prism or a Wollaston prism, that splits the laser beam 21 into a first laser beam 28 and a second laser beam 29. Note that FIG. 8 shows a modified example of the laser beam irradiation unit shown in FIG. 3. The same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted. The laser beam irradiation unit 20 shown in FIG. 8 is the same as that in the first embodiment, except that the splitting element 25-1 is a polarizing prism.

[0062] Furthermore, in the present invention, the laser processing apparatus 1 may include a unit that forms a protective film on the surface 201 of the workpiece 200 before irradiating the workpiece 200 with the laser beams 28 and 29. In this case, it is preferable to apply a liquid water-soluble resin such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP) (e.g., HogoMax (registered trademark) manufactured by Disco Corporation) to the surface 201 of the workpiece 200 and then dry the liquid water-soluble resin to cover the entire surface 201 of the workpiece 200 with the protective film. The unit that forms the protective film may be realized by providing the cleaning unit 40 with a nozzle that supplies the liquid water-soluble resin to the surface 201 of the workpiece 200, or may be realized as a unit separate from the cleaning unit 40. [Explanation of symbols]

[0063] 1. Laser processing equipment 10 Holding Unit 21 Laser beam 22 Oscillator 25 Branching element (diffractive optical element) 25-1 Branching element (polarizing prism) 26 Rotation mechanism 27 Light collecting unit 28 First laser beam 29 Second laser beam 100 Controllers 102 Index value registration section 104 Angle calculation unit 200 Workpiece 202-1, 202-2 Processing lines (1st processing line, 2nd processing line) 211 1st direction 212 Second direction 213 Index Values 251 Optical axis (axis) 271 Condenser Lens 281 Focus point 291 Focus point 1001 holding steps 1002 Focusing point interval adjustment step 1003 Laser Processing Steps θ direction (rotation angle)

Claims

1. A laser processing device, a holding unit for holding the workpiece; an oscillator for generating a laser beam; a branching element that branches the laser beam generated by the oscillator into a first laser beam and a second laser beam; a rotation mechanism that rotates the branching element around an axis passing through the center of the branching element; a focusing unit having a focusing lens that focuses the first laser beam branched by the branching element on the workpiece held by the holding unit and focuses the second laser beam branched by the branching element on the workpiece held by the holding unit; A laser processing device equipped with:

2. 2. The laser processing device according to claim 1, wherein the branching element comprises a diffractive optical element.

3. 2. The laser processing device according to claim 1, wherein the splitting element comprises a polarizing prism.

4. a controller for controlling at least the rotation mechanism; the controller includes an index value registering unit in which an index value between the focal point position of the first laser beam and the focal point position of the second laser beam is registered; an angle calculation unit that calculates a rotation angle of the branching element based on the index value registered in the index value registration unit, The laser processing device according to claim 1 , wherein the controller controls the rotation mechanism based on the rotation angle calculated by the angle calculation unit.

5. A plurality of planned processing lines extending in a first direction are set on the workpiece, 5. The laser processing apparatus according to claim 4, wherein the focal point of the first laser beam is positioned on a first planned processing line, and the focal point of the second laser beam is positioned on a second planned processing line different from the first planned processing line.

6. 2. The laser processing device according to claim 1, wherein the focusing unit forms the first laser beam perpendicular to the workpiece and forms the second laser beam perpendicular to the workpiece.

7. A laser processing method for a workpiece on which a plurality of processing lines extending in a first direction are set, a holding step of holding the workpiece with a holding unit; a laser processing step of splitting a laser beam generated by an oscillator into a first laser beam and a second laser beam by a splitting element, and focusing the first laser beam and the second laser beam on a workpiece held by the holding unit by a focusing unit while moving the focusing unit and the holding unit relatively in the first direction to perform laser processing on the workpiece along the planned processing line, In the laser processing step, the focal point of the first laser beam is positioned on a first planned processing line, and the focal point of the second laser beam is positioned on a second planned processing line different from the first planned processing line, and the first laser beam is irradiated along the first planned processing line, and the second laser beam is irradiated along the second planned processing line; a focal point distance adjusting step of adjusting the distance between the focal point of the first laser beam and the focal point of the second laser beam by rotating the branching element based on the distance in a second direction perpendicular to the first direction between the focal point of the first laser beam and the focal point of the second laser beam at least before performing the laser processing step.

Images