Laser processing equipment

Abstract

To provide a laser processing device that can efficiently divide a work-piece, while suppressing functional layers laminated on the work-piece from being peeled off.SOLUTION: In a laser processing device, a laser beam emitting unit 20 includes: a first branching unit 23 that branches a laser beam 21 emitted from a laser oscillator 22 into a first light path 30 and a second light path 40; a first light collector 32 that collects the laser beam 21 guided to the first light path 30; a second light collector 42 that collects the laser beam 21 guided to the second light path 40; a second branching unit 31, arranged on the first light path 30 between the first branching unit 23 and the first light collector 32, which branches the laser beam 21 into at least two laser beams 21; and a laser beam scanning unit 41, arranged on the second light path 40 between the first branching unit 23 and the second light collector 42, which scans the laser beams 21 and guides the beams to the second light collector 42.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a laser processing device. [Background technology]

[0002] One known method for dividing a semiconductor wafer into chips is to irradiate the wafer with a laser beam along a predetermined dividing line set on the wafer to ablate the wafer. In particular, a method in which a scanning optical system for scanning a laser beam is disposed between a laser oscillator and a condenser, and the laser beam is irradiated onto the wafer while scanning, is expected to improve productivity because it can efficiently form dividing grooves of sufficient width (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-068149 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when processing a wafer or the like having a functional layer such as a low-k film stacked on its surface using the above-mentioned method, there is a possibility that the stacked functional layer may peel off and reach the device, damaging the chip.

[0005] The present invention was made in consideration of such problems, and its purpose is to provide a laser processing device that can efficiently divide a workpiece while suppressing peeling of the functional layer laminated on the workpiece. [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 includes a holding unit that holds a workpiece, a laser beam irradiation unit that irradiates a focused pulsed laser beam onto the workpiece held by the holding unit to process the workpiece, and a moving unit that moves the holding unit and the focused point of the laser beam relatively. A processing point nozzle; the laser beam irradiation unit includes a laser oscillator, a first branching unit that branches a laser beam emitted from the laser oscillator into a first optical path and a second optical path, a first condenser that collects the laser beam guided to the first optical path, a second condenser that collects the laser beam guided to the second optical path, a second branching unit that is disposed on the first optical path between the first branching unit and the first condenser and that branches the laser beam guided to the first optical path into at least two laser beams, and a laser beam scanning unit that is disposed on the second optical path between the first branching unit and the second condenser and that scans the laser beam guided to the second optical path and guides it to the second condenser. the laser beam focused by the first condenser is spaced apart in the processing feed direction of the moving unit from the laser beam focused by the second condenser, and the processing point nozzle includes: an upper wall located below the second condenser and having a first opening that allows the laser beam focused by the second condenser to pass through; a pair of side walls hanging down from both side edges of the upper wall and provided opposite to the processing feed direction; an air inlet surrounded by the upper wall and the pair of side walls and provided at one end in an indexing feed direction perpendicular to the processing feed direction; an air suction port surrounded by the upper wall and the pair of side walls and provided at the other end in the indexing feed direction; and a second opening opening into one of the side walls, and an air flow is formed that passes from the air inlet to the air suction port, and an air flow is formed that passes from the second opening to the air suction port. It is characterized by:

[0008] In addition, in the laser processing apparatus of the present invention, the second branching unit may branch the laser beam in the width direction of the planned dividing line set on the workpiece, and form at least two laser-processed grooves along the planned dividing line.

[0009] In the laser processing apparatus of the present invention, the laser beam scanning unit includes a polygon scanner that scans the laser beam in the processing feed direction of the moving unit and guides it to the second condenser, and a third condenser between the laser oscillator and the polygon scanner. 2 and an acousto-optic element disposed in the optical path of the workpiece and scanning the laser beam in the width direction of the planned dividing line set on the workpiece.

[0010] In the laser processing apparatus of the present invention, the movement unit may include a condenser movement unit that moves the first condenser relative to the second condenser in a direction parallel to the top surface of the workpiece.

[0011] Furthermore, the laser processing apparatus of the present invention further includes a third branching unit that is arranged in the optical path between the laser oscillator and the first branching unit and that further branches the laser beam emitted from the laser oscillator into a third optical path, a third condenser that collects the laser beam that has been guided to the third optical path, and a fourth branching unit that is arranged in the third optical path between the third branching unit and the third condenser and that divides the laser beam that has been guided to the third optical path into at least two laser beams, and the laser beam collected by the first condenser and the laser beam collected by the third condenser may be spaced apart from the laser beam collected by the second condenser on opposite sides in the processing feed direction of the moving unit.

[0012] Furthermore, the laser processing apparatus of the present invention further includes a third branching unit disposed on the first optical path between the first branching unit and the second branching unit, which further branches the laser beam guided to the first optical path into a third optical path, a third condenser which focuses the laser beam guided to the third optical path, and a fourth branching unit disposed on the third optical path between the third branching unit and the third condenser, which branches the laser beam guided to the third optical path into at least two laser beams, and the laser beam focused by the first condenser and the laser beam focused by the third condenser may be spaced apart on opposite sides of the laser beam focused by the second condenser in the processing feed direction of the moving unit. [Effects of the Invention]

[0013] The present invention can efficiently divide a workpiece while suppressing peeling of a functional layer laminated on the workpiece. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a laser processing apparatus according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram illustrating a schematic configuration of a laser beam irradiation unit of the laser processing apparatus shown in FIG. [Figure 3] FIG. 3 is a perspective view schematically showing an example of the configuration of a processing point nozzle of the laser beam irradiation unit shown in FIG. [Figure 4] FIG. 4 is a plan view schematically showing an example of a laser processed groove formed by the laser processing apparatus shown in FIG. [Figure 5] FIG. 5 is an explanatory diagram illustrating a schematic configuration of a laser beam irradiation unit according to the second embodiment. [Figure 6] FIG. 6 is an explanatory diagram illustrating another state of the laser beam irradiation unit shown in FIG. [Figure 7] FIG. 7 is an explanatory diagram illustrating a schematic configuration of a laser beam irradiation unit according to the third embodiment. [Figure 8] FIG. 8 is an explanatory diagram illustrating another state 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] [First embodiment] First, the configuration of a laser processing apparatus 1 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 1 according to the first embodiment. In the following description, the X-axis direction is one direction on a horizontal plane. The Y-axis direction is a direction perpendicular to the X-axis direction on a horizontal plane. The Z-axis direction is a direction perpendicular to the X-axis and Y-axis directions. The Z-axis direction is a direction perpendicular to the X-axis and Y-axis directions. In the laser processing apparatus 1 of the first embodiment, the processing feed direction is the X-axis direction and the indexing feed direction is the Y-axis direction.

[0017] 1, the laser processing apparatus 1 includes a holding table 10, a laser beam irradiation unit 20, a moving unit 70, a display unit 80, and a control unit 90. The laser processing apparatus 1 according to the embodiment is an apparatus that processes the workpiece 100 by irradiating the workpiece 100 held on the holding table 10 with a pulsed laser beam 21 by the laser beam irradiation unit 20. The processing of the workpiece 100 by the laser processing apparatus 1 is, for example, groove processing that forms grooves in the surface of the workpiece 100, or cutting that cuts the workpiece 100 along planned dividing lines.

[0018] In the first embodiment, the workpiece 100 is a wafer such as a disk-shaped semiconductor device wafer or optical device wafer, with silicon (Si), sapphire (Al2O3), gallium arsenide (GaAs), silicon carbide (SiC), lithium tantalate (LiTa3), or the like, as the substrate 101. Note that the workpiece 100 is not limited to the embodiment, and does not have to be disk-shaped in the present invention.

[0019] The workpiece 100 has dividing lines 103 set in a grid pattern on the surface 102 of the substrate 101, and devices 104 formed in areas defined by the dividing lines 103. The devices 104 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integration), or image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors). The workpiece 100 is supported within an opening in the frame 110, with, for example, an annular frame 110 attached thereto and adhesive tape 111 having a diameter larger than the outer diameter of the workpiece 100 attached to a back surface 105 of the workpiece 100.

[0020] The holding table 10 holds the workpiece 100 on a holding surface 11. The holding surface 11 is a disk-shaped surface made of porous ceramic or the like. In the first embodiment, the holding surface 11 is a flat surface parallel to the horizontal direction. The holding surface 11 is connected to a vacuum suction source, for example, via a vacuum suction path. The holding table 10 holds the workpiece 100 placed on the holding surface 11 by suction. A plurality of clamps 12 are arranged around the holding table 10 to clamp a frame 110 that supports the workpiece 100.

[0021] The holding table 10 is rotated around an axis parallel to the Z-axis direction by a rotation unit 13. The rotation unit 13 is supported by an X-axis direction moving plate 14. The rotation unit 13 and the holding table 10 are moved in the X-axis direction by an X-axis direction moving unit 71 of the moving unit 70 via the X-axis direction moving plate 14. The rotation unit 13 and the holding table 10 are moved in the Y-axis direction by a Y-axis direction moving unit 72 of the moving unit 70 via the X-axis direction moving plate 14, the X-axis direction moving unit 71, and the Y-axis direction moving plate 15.

[0022] The laser beam irradiation unit 20 is a unit that irradiates the workpiece 100 held on the holding table 10 with a pulsed laser beam 21 having a predetermined wavelength for processing the workpiece 100. In the first embodiment, a part of the laser beam irradiation unit 20 is supported on the tip of a support column 4, the base end of which is attached to an erect wall 3 erected upright from the apparatus main body 2. The detailed configuration of the laser beam irradiation unit 20 will be described later.

[0023] The moving unit 70 is a unit that relatively moves the holding table 10 and the focal point of the laser beam 21 irradiated from the laser beam irradiation unit 20. The moving unit 70 includes an X-axis direction moving unit 71, a Y-axis direction moving unit 72, a Z-axis direction moving unit (not shown), and a condenser moving unit 73 (see FIG. 2). The condenser moving unit 73 will be described later.

[0024] The X-axis direction moving unit 71 is a unit that moves the holding table 10 and the focal point of the laser beam 21 emitted from the laser beam irradiation unit 20 relatively in the X-axis direction, which is the processing feed direction. In the first embodiment, the X-axis direction moving unit 71 moves the holding table 10 in the X-axis direction. In the first embodiment, the X-axis direction moving unit 71 is installed on the apparatus body 2 of the laser processing apparatus 1. The X-axis direction moving unit 71 supports the X-axis direction moving plate 14 so that it can be moved freely in the X-axis direction.

[0025] The Y-axis direction moving unit 72 is a unit that moves the holding table 10 and the focal point of the laser beam 21 emitted from the laser beam irradiation unit 20 relatively in the Y-axis direction, which is the indexing feed direction. In the first embodiment, the Y-axis direction moving unit 72 moves the holding table 10 in the Y-axis direction. In the first embodiment, the Y-axis direction moving unit 72 is installed on the apparatus body 2 of the laser processing apparatus 1. The Y-axis direction moving unit 72 supports the Y-axis direction moving plate 15 so that it can move freely in the Y-axis direction.

[0026] The X-axis direction moving unit 71 and the Y-axis direction moving unit 72 each include, for example, a well-known ball screw, a well-known pulse motor, and a well-known guide rail. The ball screw is rotatable about its axis. The pulse motor rotates the ball screw about its axis. The guide rail of the X-axis direction moving unit 71 is fixed to the Y-axis direction moving plate 15 and supports the X-axis direction moving plate 14 so that it can move in the X-axis direction. The guide rail of the Y-axis direction moving unit 72 is fixed to the device body 2 and supports the Y-axis direction moving plate 15 so that it can move in the Y-axis direction.

[0027] The Z-axis direction moving unit is a unit that relatively moves the holding table 10 and the focal point of the laser beam 21 emitted from the laser beam irradiation unit 20 in the Z-axis direction, which is the focus adjustment direction. The Z-axis direction moving unit moves at least the condensers of the laser beam irradiation unit 20 (in the first embodiment, a first condenser 32 and a second condenser 42, which will be described later) in the Z-axis direction. The Z-axis direction moving unit includes, for example, a well-known uniaxial actuator and pulse motor for moving at least the condensers in the Z-axis direction.

[0028] The display unit 80 is a display section configured by a liquid crystal display device or the like. The display unit 80 displays, for example, a setting screen for processing conditions, the state of the workpiece 100 imaged by an imaging unit (not shown), the state of the processing operation, etc. on a display surface 81. The imaging unit includes, for example, a micro, macro, or 3D microscope, and is provided adjacent to the irradiation portion of the laser beam 21 of the laser beam irradiation unit 20.

[0029] If the display surface 81 of the display unit 80 includes a touch panel, the display unit 80 may also include an input unit. The input unit can accept various operations, such as an operator registering processing content information. The input unit may be an external input device such as a keyboard. The information and images displayed on the display surface 81 of the display unit 80 can be switched by operations from the input unit or the like. The display unit 80 may also include an alarm device. The alarm device emits at least one of sound and light to notify the operator of the laser processing apparatus 1 of predetermined alarm information. The alarm device may be an external alarm device such as a speaker or a light-emitting device.

[0030] The control unit 90 controls each of the above-mentioned components of the laser processing apparatus 1, causing the laser processing apparatus 1 to perform processing operations on the workpiece 100. The control unit 90 is a computer including an arithmetic processing device as a calculation means, a storage device as a storage means, and an input / output interface device as a communication means. The arithmetic processing device includes, for example, a microprocessor such as a CPU (Central Processing Unit). The storage device has memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The arithmetic processing device performs various calculations based on predetermined programs stored in the storage device. The arithmetic processing device outputs various control signals to each of the above-mentioned components via the input / output interface device according to the calculation results, thereby controlling the laser processing apparatus 1.

[0031] Next, the configuration of the laser beam irradiation unit 20 will be described in detail. Fig. 2 is an explanatory diagram illustrating the schematic configuration of the laser beam irradiation unit 20 of the laser processing apparatus 1 shown in Fig. 1. Fig. 3 is a perspective view schematically showing an example of the configuration of the processing point nozzle 60 of the laser beam irradiation unit 20 shown in Fig. 1. Fig. 4 is a plan view schematically showing an example of laser processed grooves 106, 107 formed by the laser processing apparatus 1 shown in Fig. 1.

[0032] 2, in the laser beam application unit 20 of the first embodiment, a laser beam 21 is split into a first optical path 30 and a second optical path 40, and the first and second optical paths 30 and 40 are respectively applied to areas spaced apart in the processing feed direction (X-axis direction) of a workpiece 100 held on a holding surface 11 of a holding table 10. The laser beam application unit 20 includes a laser oscillator 22, a first branching unit 23, a second branching unit 31, a first condenser 32, an output adjustment mechanism 33, a λ / 4 wavelength plate 34, a laser beam scanning unit 41, a second condenser 42, mirrors 28, 38-1, 38-2, 38-3, 38-4, 48-1, 48-2, and beam dampers 39 and 49.

[0033] In Fig. 2, the arrow pointing to the right shown below the holding table 10 indicates the direction of movement of the holding table 10. In Fig. 3, the arrow pointing to the bottom left indicates the direction of travel of the laser beam 21 irradiated by the laser beam irradiation unit 20 and the processing point nozzle 60. In Fig. 3, the outline arrow indicates the direction of air flow. In Fig. 4, the arrow pointing to the left indicates the direction of travel of the laser beam 21 irradiated by the laser beam irradiation unit 20.

[0034] The laser oscillator 22 emits a laser beam 21 having a predetermined wavelength for processing the workpiece 100. The laser beam 21 emitted by the laser beam irradiation unit 20 may be a laser beam having a wavelength that is transparent to the workpiece 100, or may be a laser beam having a wavelength that is absorbent to the workpiece 100.

[0035] The first branching unit 23 branches the laser beam 21 emitted from the laser oscillator 22 into a first optical path 30 and a second optical path 40. The first branching unit 23 is a polarizing beam splitter (PBS) that splits the incident laser beam 21 into orthogonal components of S-polarized light and P-polarized light. In the first embodiment, the first branching unit 23 may be a beam splitter that has predetermined transmittance and reflectance and directs the transmitted laser beam 21 to the first optical path 30 and the reflected laser beam 21 to the second optical path 40.

[0036] The second branching unit 31 is disposed on the first optical path 30 between the first branching unit 23 and the first condenser 32. The second branching unit 31 branches the laser beam 21 guided to the first optical path 30 into at least two laser beams. The second branching unit 31 branches the laser beam 21 in the width direction (Y-axis direction) of a planned dividing line 103 (see FIG. 1) set on the workpiece 100, and forms at least two laser-processed grooves 106 (see FIG. 4) along the planned dividing line 103.

[0037] In the first embodiment, the second splitting unit 31 is a Wollaston prism that splits the incident laser beam 21 into two orthogonal linearly polarized laser beams 21. The two laser beams 21 emitted from the Wollaston prism are tilted relative to the incident direction. In addition, the Wollaston prism can change the spacing between the two emitted laser beams 21 by rotating.

[0038] The first condenser 32 condenses the laser beam 21 guided to the first optical path 30. The first condenser 32 condenses and irradiates the laser beam, which has been split into at least two beams by the second splitter unit 31, onto the workpiece 100 held on the holding surface 11 of the holding table 10. The first condenser 32 is moved in the Z-axis direction by a Z-axis movement unit (not shown), and the height position of the focal point is adjusted.

[0039] In the first embodiment, the first collector 32 is moved by the collector moving unit 73 in a direction parallel to the top surface of the workpiece 100 (horizontal direction) relative to the second collector 42. The collector moving unit 73 includes, for example, a holder that holds the first collector 32, and a two-axis actuator and an ultrasonic motor that move the holder in the horizontal direction.

[0040] The output adjustment mechanism 33 is disposed on the first optical path 30 between the first branching unit 23 and the second branching unit 31. The output adjustment mechanism 33 adjusts the output of the laser beam 21 guided to the first optical path 30. The output adjustment mechanism 33 includes, for example, an attenuator equipped with a λ / 2 wave plate, a beam splitter, a beam dumper, and the like. The λ / 2 wave plate changes the linear polarization direction of the incident laser beam 21 according to the rotation angle. The beam splitter reflects the laser beam 21 having a predetermined linear polarization direction, out of the laser beam 21 that has passed through the λ / 2 wave plate, toward the beam dumper, and transmits the laser beam 21 having a linear polarization direction other than the predetermined linear polarization direction.

[0041] The λ / 4 wave plate 34 is disposed on the first optical path 30 between the second branching unit 31 and the first condenser 32. The λ / 4 wave plate 34 gives a phase difference of λ / 4 (90°) to the two orthogonal polarized components of the incident laser beam 21, thereby converting the linearly polarized light into circularly polarized light.

[0042] The laser beam scanning unit 41 is disposed on the second optical path 40 between the first branching unit 23 and the second condenser 42. The laser beam scanning unit 41 is a unit that scans the laser beam 21 and guides it to the second condenser 42. In the first embodiment, the laser beam scanning unit 41 includes an acousto-optic deflector (AOD) 43 and a polygon scanner 44.

[0043] The acousto-optical element 43 is disposed on the second optical path 40 between the laser oscillator 22 and the polygon scanner 44. The acousto-optical element 43 scans the laser beam 21 in the width direction (Y-axis direction) of the dividing lines 103 (see FIG. 1 ) set on the workpiece 100. When a predetermined high frequency is applied to the acousto-optical element 43, the acousto-optical element 43 deflects the optical axis of the incident laser beam 21 in a predetermined direction (Y-axis direction in the first embodiment) and performs scanning. The acousto-optical element 43 adjusts the angle at which the optical axis of the laser beam 21 is deflected in accordance with the frequency of the applied high frequency. As a result, the laser beam 21 is scanned in the Y-axis direction.

[0044] The polygon scanner 44 scans the laser beam 21 in the processing feed direction (X-axis direction) of the moving unit 70 and guides it to the second condenser 42. The polygon scanner 44 includes a scanning mirror 44-1 and a scanning motor 44-2.

[0045] The scanning mirror 44-1 is provided so as to be rotatable or swingable about an axis parallel to the indexing feed direction (Y-axis direction). The scanning mirrors 44-1 are provided on the side surfaces of a polygonal prism (an octagonal prism in the first embodiment) that rotates about its axis. The axis of the scanning mirror 44-1 is held by a mirror holder (not shown). The front focal point of the second condenser 42 is positioned on the scanning mirror 44-1, on which the laser beam 21 is incident. The scanning motor 44-2 outputs a rotational driving force for rotating or swinging the scanning mirror 44-1 about its axis.

[0046] The polygon scanner 44 reflects the laser beam 21, which has been scanned in the Y-axis direction by the acousto-optical element 43, in a direction parallel to the XZ plane toward the second collector 42 using the scanning mirror 44-1, and rotates the scanning mirror 44-1 around an axis parallel to the Y-axis direction, thereby scanning the laser beam 21 in the X-axis direction.

[0047] The second condenser 42 condenses the laser beam 21 guided to the second optical path 40. The second condenser 42 includes an fθ lens. The fθ lens is a composite lens made up of a plurality of lenses. The second condenser 42 condenses and irradiates the laser beam 21, which has been scanned in the Y-axis direction by the acousto-optical element 43 and in the X-axis direction by the polygon scanner 44, onto the workpiece 100 held on the holding surface 11 of the holding table 10. The second condenser 42 is moved in the Z-axis direction by a Z-axis movement unit (not shown), and the height position of the focal point is adjusted.

[0048] The second collector 42 is disposed at a position spaced rearward from the first collector 32 in the processing feed direction (X-axis direction) of the moving unit 70. In other words, the laser beam 21 collected by the first collector 32 is spaced forward from the laser beam 21 collected by the second collector 42 in the processing feed direction (X-axis direction) of the moving unit 70.

[0049] 3, an irradiation area 21-1 of the laser beam 21 focused by the first collector 32 is spaced forward in the processing feed direction (X-axis direction) from an irradiation area 21-2 of the laser beam 21 focused by the second collector 42. That is, on the intended division line 103 of the workpiece 100, at the same position in the traveling direction of the laser beam 21, the laser beam 21 focused by the first collector 32 is irradiated before the laser beam 21 focused by the second collector 42.

[0050] As shown in FIG. 4, the laser beam 21 focused by the first collector 32 forms two laser-processed grooves 106 along the intended division line 103, a process known as pie-cutting. In pie-cutting, the functional layer of the workpiece 100 is divided. The laser beam 21 focused by the second collector 42 forms a wide laser-processed groove 107 that covers the area between the two laser-processed grooves 106 formed by the laser beam 21 focused by the first collector 32, a process known as hollowing. The collector moving unit 73 shown in FIG. 2 can align the laser-processed grooves 106, 107 shown in FIG. 4 by adjusting the relative horizontal distance between the first collector 32 and the second collector 42.

[0051] The mirrors 28, 38-1, 38-2, 38-3, 38-4, 48-1, and 48-2 are disposed on the optical path of the laser beam 21. The mirrors 28, 38-1, 38-2, 38-3, 38-4, 48-1, and 48-2 reflect the laser beam 21 and guide it to each of the optical components of the laser beam application unit 20.

[0052] The mirror 28 is disposed on the optical path between the laser oscillator 22 and the first branching unit 23. The mirror 38-1 is disposed on the first optical path 30 between the first branching unit 23 and the output adjustment mechanism 33. The mirrors 38-2 and 38-3 are disposed on the first optical path 30 between the output adjustment mechanism 33 and the second branching unit 31. The mirror 38-4 is disposed on the first optical path 30 between the λ / 4 wave plate 34 and the first condenser 32. The mirrors 48-1 and 48-2 are disposed on the second optical path 40 between the acousto-optical element 43 and the polygon scanner 44.

[0053] In the first embodiment, the mirror 38-2 is a galvanometer mirror included in the galvanometer scanner. That is, the mirror 38-2 can change the scanning angle of the laser beam 21 by rotating with respect to the incident angle of the laser beam 21, and functions as a shutter that blocks the laser beam 21 from the first optical path 30. The mirror 38-2 functioning as a shutter reflects the laser beam 21 toward a beam dumper 39. The beam dumper 39 terminates the laser beam 21 incident from the mirror 38-2.

[0054] In the first embodiment, the mirror 48-1 is a galvanometer mirror included in the galvanometer scanner. That is, the mirror 48-1 can change the scanning angle of the laser beam 21 by rotating with respect to the incident angle of the laser beam 21, and functions as a shutter that blocks the laser beam 21 from the second optical path 40. The mirror 48-1 functioning as a shutter reflects the laser beam 21 toward a beam dumper 49. The beam dumper 39 terminates the laser beam 21 incident from the mirror 48-1.

[0055] The shutters provided in the first optical path 30 and the second optical path 40 are not limited to those in the first embodiment that use galvano scanners, but may be mechanical shutters such as cylinders, for example.

[0056] The laser processing apparatus 1 further includes a processing point nozzle 60 shown in Fig. 3. The processing point nozzle 60 is provided below the processing head attached to the tip of the support column 4. The processing point nozzle 60 allows the laser beam 21 emitted from the laser beam irradiation unit 20 to pass through. The processing point nozzle 60 of the embodiment allows the laser beam 21 focused by the second condenser 42 to pass through. The processing point nozzle 60 includes an upper wall 61, side walls 62 and 63, an air inlet 64, an air suction port 65, a first opening 66, and a second opening 67.

[0057] The upper wall 61 is located below the second collector 42. The side walls 62, 63 are provided hanging down from both side edges of the upper wall 61. The upper edge of the side wall 62 is connected to the side edge of the upper wall 61 on the side where the first collector 32 is provided relative to the second collector 42 in the X-axis direction. The side wall 63 is provided opposite the side wall 62 in the X-axis direction. The upper edge of the side wall 63 is connected to the side edge of the upper wall 61 on the side where the second collector 42 is provided relative to the first collector 32 in the X-axis direction. In other words, the processing point nozzle 60 is configured in an inverted U-shape when viewed in the Y-axis direction by the upper wall 61 and the side walls 62, 63.

[0058] The air inlet 64 is an opening surrounded by the top wall 61 and the side walls 62, 63 and provided at one end in the Y-axis direction. The air suction port 65 is an opening surrounded by the top wall 61 and the side walls 62, 63 and provided at the other end in the Y-axis direction, facing the air inlet 64. The air suction port 65 is connected to a suction source (not shown). By being sucked by the suction source, an air flow is formed that passes from the air inlet 64 through the inside of the processing point nozzle 60 and escapes from the air suction port 65. This allows debris generated during processing by the laser beam 21 focused on the second collector 42 to be sucked in.

[0059] The first opening 66 is provided in the upper wall 61. The first opening 66 is provided directly below the second condenser 42 and allows the laser beam 21 condensed by the second condenser 42 to pass through.

[0060] The second opening 67 is provided in the side wall 62. When sucked by a suction source (not shown), an air flow is formed that passes from the second opening 67 through the inside of the processing point nozzle 60 and escapes through the air suction port 65. This allows debris generated during processing by the laser beam 21 focused on the first collector 32 to be sucked in. Note that an air blow nozzle that sprays air from the second opening 67 toward the inside of the processing point nozzle 60 may also be provided.

[0061] As described above, the laser processing apparatus 1 according to the first embodiment splits the laser beam 21 into the first optical path 30 and the second optical path 40, and first forms the laser groove 106, which separates the functional layer, with at least two laser beams 21 guided along the first optical path 30. After the laser groove 106 is formed, the laser beam 21 guided along the second optical path 40 forms the laser groove 107, and ablates the area surrounded by the laser groove 106. This makes it possible to efficiently divide the workpiece 100 while suppressing peeling of the functional layer laminated on the workpiece 100. Furthermore, because the above processing can be performed with a single laser processing apparatus 1, it has the effect of reducing the footprint required for equipment for processing the workpiece 100.

[0062] The present invention is not limited to the first embodiment. In other words, various modifications can be made without departing from the gist of the present invention. For example, as shown in the second and third embodiments, the laser beam 21 may be split into three beams.

[0063] Second Embodiment The configuration of a laser beam irradiation unit 20-1 according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 5 is an explanatory diagram illustrating the schematic configuration of the laser beam irradiation unit 20-1 according to the second embodiment. Fig. 6 is an explanatory diagram illustrating another state of the laser beam irradiation unit 20-1 shown in Fig. 5. In the following description, the same components as those in the laser beam irradiation unit 20 of the first embodiment will be assigned the same reference numerals, and description thereof will be omitted.

[0064] As shown in Figures 5 and 6, the laser beam irradiation unit 20-1 of the second embodiment branches the laser beam 21 into a first optical path 30, a second optical path 40, and a third optical path 50, and irradiates each of these onto areas spaced apart in the processing feed direction (X-axis direction) of the workpiece 100 held on the holding surface 11 of the holding table 10.

[0065] The laser beam irradiation unit 20-1 of the second embodiment differs from the laser beam irradiation unit 20 of the first embodiment in that it includes a third branching unit 25, a fourth branching unit 51, a third condenser 52, an output adjustment mechanism 53, a λ / 4 wave plate 54, mirrors 58-1, 58-2, 58-3, and a beam dumper 59 instead of the mirror 28. In addition, the moving unit 70 (see FIG. 1) further includes a condenser moving unit 74.

[0066] The third branching unit 25 branches the laser beam 21 emitted from the laser oscillator 22 into an optical path toward the first branching unit 23 and the third optical path 50. The third branching unit 25 is a polarizing beam splitter that splits the incident laser beam 21 into orthogonal components of S-polarized light and P-polarized light. In the second embodiment, the third branching unit 25 may be, for example, a beam splitter that has predetermined transmittance and reflectance and that guides the transmitted laser beam 21 toward the first branching unit 23 and guides the reflected laser beam 21 to the third optical path 50.

[0067] The fourth branching unit 51 is disposed on the third optical path 50 between the third branching unit 25 and the third condenser 52. The fourth branching unit 51 branches the laser beam 21 guided to the third optical path 50 into at least two laser beams. The fourth branching unit 51 branches the laser beam 21 in the width direction (Y-axis direction) of a planned dividing line 103 (see FIG. 1) set on the workpiece 100, and forms at least two laser-processed grooves 106 (see FIG. 4) along the planned dividing line 103.

[0068] The third condenser 52 condenses the laser beam 21 guided to the third optical path 50. The third condenser 52 condenses and irradiates the laser beam, which has been split into at least two beams by the fourth splitter unit 51, onto the workpiece 100 held on the holding surface 11 of the holding table 10. The third condenser 52 is moved in the Z-axis direction by a Z-axis direction moving unit (not shown) to adjust the height position of the focal point.

[0069] The third condenser 52 is disposed at a position spaced apart from the second condenser 42 in the processing feed direction (X-axis direction) of the moving unit 70, and at a symmetrical position on the opposite side of the first condenser 32, with the second condenser 42 in between. That is, the laser beam 21 collected by the first condenser 32 is spaced further forward than the laser beam 21 collected by the second condenser 42 in the processing feed direction (X-axis direction) of the moving unit 70, on the outward path shown in Fig. 5. In contrast, the laser beam 21 collected by the third condenser 52 is spaced further forward than the laser beam 21 collected by the second condenser 42 in the processing feed direction (X-axis direction) of the moving unit 70, on the return path shown in Fig. 6.

[0070] In the second embodiment, the third collector 52 is moved by a collector moving unit 74 in a direction parallel to the top surface of the workpiece 100 (horizontal direction) relative to the second collector 42. The collector moving unit 74 includes, for example, a holder that holds the third collector 52, and a two-axis actuator and an ultrasonic motor for moving the holder in the horizontal direction.

[0071] The output adjustment mechanism 53 is disposed on the third optical path 50 between the third branching unit 25 and the fourth branching unit 51. The output adjustment mechanism 53 adjusts the output of the laser beam 21 guided to the third optical path 50. The output adjustment mechanism 53 includes, for example, an attenuator equipped with a λ / 2 wave plate, a beam splitter, a beam dumper, and the like. The λ / 2 wave plate changes the linear polarization direction of the incident laser beam 21 according to the rotation angle. The beam splitter reflects the laser beam 21 having a predetermined linear polarization direction, out of the laser beam 21 that has passed through the λ / 2 wave plate, toward the beam dumper, and transmits the laser beam 21 having a linear polarization direction other than the predetermined linear polarization direction.

[0072] The λ / 4 wave plate 54 is disposed on the third optical path 50 between the fourth splitter unit 51 and the third condenser 52. The λ / 4 wave plate 54 gives a phase difference of λ / 4 (90°) to the two orthogonal polarized light components of the incident laser beam 21, thereby converting the linearly polarized light into circularly polarized light.

[0073] The mirrors 58-1, 58-2, and 58-3 are disposed on the third optical path 50 of the laser beam 21. The mirrors 58-1, 58-2, and 58-3 reflect the laser beam 21 and guide it to each optical component of the laser beam application unit 20. The mirrors 58-1, 58-2, and 58-3 are disposed on the third optical path 50 between the output adjustment mechanism 53 and the fourth branching unit 51.

[0074] In the second embodiment, the mirror 58-1 is a galvanometer mirror included in the galvanometer scanner. That is, the mirror 58-1 can change the scanning angle of the laser beam 21 by rotating with respect to the incident angle of the laser beam 21, and functions as a shutter that blocks the laser beam 21 from the third optical path 50. The mirror 58-1 functioning as a shutter reflects the laser beam 21 toward a beam dumper 59. The beam dumper 59 terminates the laser beam 21 incident from the mirror 58-1.

[0075] Third Embodiment The configuration of a laser beam irradiation unit 20-2 according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 7 is an explanatory diagram illustrating the schematic configuration of the laser beam irradiation unit 20-2 according to the third embodiment. Fig. 8 is an explanatory diagram illustrating another state of the laser beam irradiation unit 20-2 shown in Fig. 7. In the following description, the same components as those in the laser beam irradiation unit 20 of the first embodiment or the laser beam irradiation unit 20-1 of the second embodiment will be assigned the same reference numerals, and description thereof will be omitted.

[0076] 7 and 8, the laser beam application unit 20-2 of the third embodiment, like the laser beam application unit 20-1 of the second embodiment, branches the laser beam 21 into a first optical path 30, a second optical path 40, and a third optical path 50, and irradiates the workpiece 100 held on the holding surface 11 of the holding table 10 with the respective optical paths spaced apart in the processing feed direction (X-axis direction). However, while the laser beam application unit 20-1 of the second embodiment is configured to branch the laser beam into the third optical path 50 before branching into the first optical path 30 and the second optical path 40, the laser beam application unit 20-2 of the third embodiment branches the laser beam from the first optical path 30 into the third optical path 50 after branching into the first optical path 30 and the second optical path 40.

[0077] The laser beam irradiation unit 20-2 of the third embodiment differs from the laser beam irradiation unit 20-1 of the second embodiment in that it includes a third branching unit 35, λ / 2 wave plates 36, 37, 57, and mirrors 48-3, 58-4, 58-5 instead of the third branching unit 25, output adjustment mechanism 53, mirrors 38-1, 38-2, 38-3, 58-1, 58-2, 58-3, and beam damper 59. In addition, a fourth branching unit 51 is disposed on the third optical path 50 between the third branching unit 35 and the third condenser 52.

[0078] The third branching unit 35 is disposed on the first optical path 30 between the output adjustment mechanism 33 and the second branching unit 31. The third branching unit 35 branches the laser beam 21 guided to the first optical path 30 into the first optical path 30 directed toward the second branching unit 31, and a third optical path 50. The third branching unit 35 is a polarizing beam splitter that splits the incident laser beam 21 into orthogonal components of S-polarized light and P-polarized light.

[0079] The λ / 2 wave plate 36 is disposed on the first optical path 30 between the output adjustment mechanism 33 and the third branching unit 35. The λ / 2 wave plate 36 changes the polarization direction of the linearly polarized light of the incident laser beam 21 in accordance with the rotation angle. That is, the λ / 2 wave plate 36 changes the direction in which the laser beam 21 is emitted from the third branching unit 35 to either the first optical path 30 or the third optical path 50 in accordance with the rotation angle.

[0080] The λ / 2 wave plate 37 is disposed on the first optical path 30 between the third branching unit 35 and the second branching unit 31. The λ / 2 wave plate 37 changes the polarization direction of the linearly polarized laser beam 21 incident thereon in accordance with the rotation angle. The λ / 2 wave plate 37 converts the laser beam 21 guided to the first optical path 30 into an unpolarized state.

[0081] The λ / 2 wave plate 57 is disposed on the third optical path 50 between the third branching unit 35 and the fourth branching unit 51. The λ / 2 wave plate 57 changes the polarization direction of the linearly polarized laser beam 21 incident thereon in accordance with the rotation angle. The λ / 2 wave plate 57 converts the laser beam 21 guided to the third optical path 50 into an unpolarized state.

[0082] The mirrors 48-3, 58-4, and 58-5 are disposed on the optical path of the laser beam 21. The mirrors 48-3, 58-4, and 58-5 reflect the laser beam 21 and guide it to the respective optical components of the laser beam application unit 20.

[0083] Mirror 48-3 is disposed on the second optical path 40 between the first branching unit 23 and the acousto-optical element 43. Mirror 58-4 is disposed on the third optical path 50 between the third branching unit 35 and the λ / 2 wave plate 37. Mirror 58-5 is disposed on the third optical path 50 between the λ / 4 wave plate 54 and the third condenser 52. In FIGS. 7 and 8, a mirror (not shown) may be appropriately disposed to detour the laser beam 21 toward or away from the paper at locations where the optical paths of the laser beam 21 interfere.

[0084] As described above, the laser processing apparatuses equipped with the laser beam irradiation units 20-1 and 20-2 according to the second and third embodiments have the first and third condensers 32 and 52 positioned on either side of the second condenser 42 in the processing feed direction, and can selectively irradiate the laser beam 21 guided to the first optical path 30 and the laser beam 21 guided to the third optical path 50. As a result, in both the forward and backward processing feed directions, the laser beam 21 guided to the second optical path 40 forms the laser processed groove 107, and before ablating the area surrounded by the laser processed groove 106, the laser processed groove 106 that separates the functional layer can be first formed by at least two laser beams 21 guided to the first optical path 30 or the third optical path 50. [Explanation of symbols]

[0085] 1. Laser processing equipment 10 Holding table 20, 20-1, 20-2 Laser beam irradiation unit 21 Laser Beam 22 Laser oscillator 23 First branch unit 25 Third Branch Unit 30 First optical path 31 Second branch unit 32 First Concentrator 40 Second optical path 41 Laser beam scanning unit 42 Second Concentrator 43 Acousto-optical element 44 Polygon Scanner 50 Third optical path 51 4th branch unit 52 Third Concentrator 70 Mobile Units 73, 74 Concentrator moving unit 100 Workpiece 106, 107 Laser-machined grooves

Claims

1. a holding unit for holding the workpiece; a laser beam irradiation unit that irradiates a workpiece held by the holding unit with a focused pulsed laser beam to process the workpiece; a moving unit that moves the holding unit and the focal point of the laser beam relatively; A processing point nozzle; A laser processing device comprising: The laser beam irradiation unit comprises: A laser oscillator; a first branching unit that branches the laser beam emitted from the laser oscillator into a first optical path and a second optical path; a first condenser that condenses the laser beam guided to the first optical path; a second condenser that condenses the laser beam guided to the second optical path; a second branching unit disposed on the first optical path between the first branching unit and the first condenser, the second branching unit branching the laser beam guided to the first optical path into at least two laser beams; a laser beam scanning unit disposed on the second optical path between the first branching unit and the second condenser, for scanning the laser beam guided to the second optical path and guiding it to the second condenser; Including, the laser beam focused by the first condenser is spaced apart from the laser beam focused by the second condenser in the processing feed direction of the moving unit; The processing point nozzle is an upper wall positioned below the second collector and having a first opening for allowing the laser beam collected by the second collector to pass therethrough; a pair of side walls extending downward from both side edges of the upper wall and facing each other in the processing feed direction; an air inlet surrounded by the top wall and the pair of side walls and provided at one end in an indexing feed direction perpendicular to the processing feed direction; an air suction port surrounded by the top wall and the pair of side walls and provided at the other end in the indexing feed direction; a second opening opening to one of the side walls; Including, An air flow is formed that flows from the air inlet to the air suction port, A laser processing device characterized in that an air flow is formed that escapes from the second opening to the air suction port.

2. the second branching unit branches the laser beam in a width direction of a planned dividing line set on the workpiece, and forms at least two laser processed grooves along the planned dividing line. The laser processing device according to claim 1.

3. The laser beam scanning unit a polygon scanner that scans the laser beam in the processing feed direction of the moving unit and guides it to the second condenser; an acousto-optical element disposed on the second optical path between the laser oscillator and the polygon scanner, for scanning the laser beam in the width direction of the planned dividing line set on the workpiece; characterized in that it comprises 3. The laser processing device according to claim 1 or 2.

4. the moving unit includes a collector moving unit that moves the first collector relative to the second collector in a direction parallel to the top surface of the workpiece. The laser processing device according to any one of claims 1 to 3.

5. a third branching unit disposed in an optical path between the laser oscillator and the first branching unit, for further branching the laser beam emitted from the laser oscillator into a third optical path; a third condenser that condenses the laser beam guided to the third optical path; a fourth branching unit disposed on the third optical path between the third branching unit and the third condenser, and configured to branch the laser beam guided to the third optical path into at least two laser beams; Further comprising: the laser beam focused by the first collector and the laser beam focused by the third collector are spaced apart on opposite sides to each other in the processing feed direction of the moving unit relative to the laser beam focused by the second collector. The laser processing device according to any one of claims 1 to 4.

6. a third branching unit disposed on the first optical path between the first branching unit and the second branching unit, and configured to further branch the laser beam guided to the first optical path into a third optical path; a third condenser that condenses the laser beam guided to the third optical path; a fourth branching unit disposed on the third optical path between the third branching unit and the third condenser, and configured to branch the laser beam guided to the third optical path into at least two laser beams; Further comprising: the laser beam focused by the first collector and the laser beam focused by the third collector are spaced apart on opposite sides to each other in the processing feed direction of the moving unit relative to the laser beam focused by the second collector. The laser processing device according to any one of claims 1 to 4.

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