Laser processing device

Abstract

The invention provides a laser processing apparatus capable of suppressing deviation of a processing position. The laser processing apparatus includes: a laser oscillator that generates a laser beam that is focused on and irradiated to a workpiece held by a holding unit; and a scanning unit that scans the laser beam in an X direction perpendicular to the Y direction with respect to the workpiece. The scanning unit includes: a scanner that scans the laser beam emitted from the laser oscillator in the X direction; a first lens to which the laser beam from the scanner is incident, the first lens making the laser beam perpendicular to the workpiece; and a second lens having a curvature at which the laser beam emitted from the first lens converges in the Y direction, the first lens and the second lens being respectively set so that the length in the X direction is greater than the length in the X direction of the workpiece held by the holding unit.

Description

Technical Field

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

[0002] Laser processing devices are currently widely used. These devices use a moving mechanism to converge and irradiate the workpiece with a laser beam and to move a holding unit that holds the workpiece relative to the laser beam in a processing feed direction and a transfer feed direction, thereby performing laser processing on the workpiece (for example, refer to patent document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-031871

[0004] The moving mechanism of the laser processing device disclosed in Patent Document 1 uses an axis unit that utilizes a ball screw and a linear motor. Due to the frictional heat generated by the movement of the processing feed, the axis unit and the surroundings of the focusing lens holder may thermally expand and the position of the focal point of the laser beam may be deviated from the desired position. Therefore, the optical system that appropriately corrects the laser processing position is desired to be further improved. Summary of the invention

[0005] Therefore, an object of the present invention is to provide a laser processing apparatus capable of suppressing deviation of a processing position.

[0006] According to one aspect of the present invention, a laser processing device is provided, wherein the laser processing device comprises: a holding unit that holds a workpiece; a laser oscillator that generates a laser beam that converges on the workpiece held by the holding unit and irradiates the workpiece; an indexing and feeding unit that moves the holding unit that holds the workpiece relative to a focal point of the laser beam in a Y direction; and a scanning unit that scans the laser beam emitted from the laser oscillator in an X direction perpendicular to the Y direction relative to the workpiece held by the holding unit, wherein the scanning unit The invention comprises: a scanner for scanning the laser beam emitted from the laser oscillator in the X direction; a first lens on which the laser beam from the scanner is incident, the first lens having a curvature in the X direction that makes the laser beam perpendicular to the workpiece held by the holding unit; and a second lens having a curvature in the Y direction that makes the laser beam emitted from the first lens converge in the Y direction, the first lens and the second lens being respectively set so that the length in the X direction is greater than the length in the X direction of the workpiece held by the holding unit.

[0007] The scanner is preferably formed of a polygonal scanner having a plurality of reflection mirrors for reflecting the laser beam emitted from the laser oscillator.

[0008] Preferably, the laser processing device also has a liquid supply unit, which is arranged between the second lens and the holding unit, and supplies liquid to at least the area on the upper surface of the workpiece held by the holding unit that is irradiated with the laser beam. The liquid supply unit includes: a transmission window that allows the laser beam converged by the second lens to pass through; and a liquid supply part, which has a liquid nozzle formed adjacent to the transmission window in the Y direction.

[0009] The present invention has an effect of being able to suppress deviation of the processing position. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a perspective view schematically showing a configuration example of the laser processing apparatus according to the first embodiment.

[0011] Figure 2 It is a perspective view schematically showing a wafer which is a processing target of the laser processing apparatus according to the first embodiment.

[0012] Figure 3 yes Figure 1 Another perspective view of the laser processing device shown.

[0013] Figure 4 It is schematically shown Figure 1 A perspective view of the structure of a laser beam irradiation unit of a laser processing device shown in FIG.

[0014] Figure 5 It is schematically shown Figure 4 A perspective view of a first lens and the like of a laser beam irradiation unit is shown.

[0015] Figure 6 It is schematically shown Figure 4 A perspective view of a second lens and the like of a laser beam irradiation unit is shown.

[0016] Figure 7 It is a perspective view schematically showing a configuration example of a laser processing apparatus according to a second embodiment.

[0017] Figure 8 yes Figure 7 Another perspective view of the laser processing device shown.

[0018] Fig. 9 Shown in partial section Figure 7 A side view of the structure of a liquid supply unit, etc. of the laser processing device shown.

[0019] Fig.10 Observed from below Fig. 9 A plan view of the liquid supply unit is shown.

[0020] Fig.11 Shown in partial section Figure 7 A side view of the laser processing device shown in the figure is in the process of processing.

[0021] Description of symbols

[0022] 1. 1-2: laser processing device; 10: holding unit; 21: laser beam; 22: focusing point; 23: laser oscillator; 24: scanning unit; 27: scanner; 28: first lens; 29: second lens; 30: liquid supply unit; 32: transmission window; 33: liquid supply part; 35: liquid injection port; 42: Y-axis moving unit (indexing and feeding unit); 200: workpiece; 271: reflector. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the constituent elements described below include elements that can be easily thought of by a person skilled in the art, and substantially the same elements. Furthermore, the structures described below can be appropriately combined. In addition, various omissions, substitutions or changes in the structure can be made within the scope of the gist of the present invention.

[0024] [First embodiment]

[0025] A laser processing apparatus according to a first embodiment of the present invention will be described with reference to the drawings. Figure 1 It is a perspective view schematically showing a configuration example of the laser processing apparatus according to the first embodiment. Figure 2 It is a perspective view schematically showing a wafer which is a processing target of the laser processing apparatus according to the first embodiment. Figure 3 yes Figure 1 Another perspective view of the laser processing device shown.

[0026] Implementation Method Figure 1 The laser processing device 1 shown is a Figure 2 The laser processing device 1 of the embodiment processes the workpiece 200. The workpiece 200 to be processed by the laser processing device 1 is a disk-shaped semiconductor wafer, an optical device wafer, etc., with a substrate 201 made of silicon (Si), gallium arsenide (GaAs), silicon carbide (SiC), or sapphire.

[0027] like Figure 2As shown, the workpiece 200 has devices 204 formed in the regions divided by the intersecting plurality of dividing lines 203 on the front side 202. The device 204 is, for example, an integrated circuit such as IC (Integrated Circuit) or LSI (Large Scale Integration), an image sensor such as CCD (Charge Coupled Device) or CMOS (Complentary Metal Oxid Semiconductor), an optical element such as LED (Light-Emission Diode), MEMS (Micro Electro Mechanical Systems) or a semiconductor memory (semiconductor storage device).

[0028] The workpiece 200 is divided into individual chips 210 along the predetermined dividing line 203. The chip 210 includes a portion of the substrate 201 and the device 204. Figure 2 As shown, an adhesive tape 211 having an annular frame 212 mounted on the outer edge is attached to the back side 205 of the workpiece 200 located on the opposite side of the front side 202, and the adhesive tape 211 is attached to the back side 205 of the workpiece 200. Figure 1 The laser processing device 1 shown is divided into individual chips 210. In addition, the adhesive tape 211 may be an adhesive tape having a base material (the base material is made of a resin having non-adhesiveness and flexibility) and a paste layer (the paste layer is laminated on the base material and is made of a resin having adhesiveness and flexibility) and the paste layer is adhered to the annular frame 212 and the workpiece 200, or a so-called paste-free tape which is composed of only a base material (the base material is made of a thermoplastic resin having non-adhesiveness) and is thermally pressed to the annular frame 212 and the workpiece 200.

[0029] The laser processing device 1 of the first embodiment is a processing device that divides a workpiece 200 formed with a plurality of predetermined dividing lines 203 along the predetermined dividing lines 203 to produce a plurality of chips 210. The laser processing device 1 of the first embodiment is a processing device that sets a focal point 22 of a pulsed laser beam 21 of a wavelength that is absorbent to a substrate 201 constituting the workpiece 200 on a front surface 202 of the substrate 201, and irradiates the workpiece 200 with the laser beam 21 from the front surface 202 along the predetermined dividing lines 203, thereby performing laser processing (also referred to as ablation processing) on ​​the workpiece 200.

[0030] like Figure 1 As shown, the laser processing apparatus 1 includes: a holding unit 10 for holding a workpiece 200 ; a laser beam irradiation unit 20 ; a moving unit 40 ; an imaging unit 50 ; and a controller 100 .

[0031] The holding unit 10 holds the workpiece 200 using a holding surface 11 parallel to the horizontal direction. The holding surface 11 is a disk-shaped material formed of porous ceramics, quartz, etc., and has a suction port opened on the surface, and is connected to a vacuum suction source (not shown) via a suction path (not shown). The holding unit 10 is sucked by the vacuum suction source to suck and hold the workpiece 200 placed on the holding surface 11. A plurality of clamping parts 12 are arranged around the holding unit 10, and the clamping parts 12 clamp the annular frame 212 that supports the workpiece 200 in the opening.

[0032] In addition, the holding unit 10 is rotated around an axis parallel to the Z direction (the Z direction is perpendicular to the holding surface 11 and parallel to the vertical direction) by the rotation moving unit 43 of the moving unit 40. The holding unit 10 is moved in the X direction (corresponding to the processing direction) parallel to the horizontal direction by the X-axis moving unit 41 of the moving unit 40 together with the rotation moving unit 43, and is moved in the Y direction parallel to the horizontal direction and perpendicular to the X direction by the Y-axis moving unit 42. The holding unit 10 is moved between the processing area below the laser beam irradiation unit 20 and the loading and unloading area away from the bottom of the laser beam irradiation unit 20 for loading and unloading the workpiece 200 by the moving unit 40.

[0033] The moving unit 40 moves the holding unit 10 and the focal point 22 of the laser beam 21 irradiated by the laser beam irradiation unit 20 relative to each other around an axis parallel to the X direction, the Y direction, and the Z direction. The X direction and the Y direction are directions perpendicular to each other and parallel to the holding surface 11 (i.e., the horizontal direction). The Z direction is a direction perpendicular to both the X direction and the Y direction.

[0034] The moving unit 40 includes: an X-axis moving unit 41, which is a processing feed unit that moves the holding unit 10 in the X direction; a Y-axis moving unit 42, which is an indexing feed unit that moves the holding unit 10 in the Y direction; and a rotation moving unit 43, which rotates the holding unit 10 around an axis parallel to the Z direction.

[0035] The Y-axis moving unit 42 is an indexing and feeding unit that moves the holding unit 10 holding the workpiece 200 in the Y direction relative to the focal point 22 of the laser beam 21 of the laser beam irradiation unit 20. In the first embodiment, the Y-axis moving unit 42 is provided on the device body 2 of the laser processing device 1. The Y-axis moving unit 42 supports the moving plate 4 supporting the X-axis moving unit 41 so as to be movable in the Y direction.

[0036] The X-axis moving unit 41 is a processing feeding unit that moves the holding unit 10 relative to the focal point 22 of the laser beam 21 of the laser beam irradiation unit 20 in the X direction. The X-axis moving unit 41 is provided on the moving plate 4. The X-axis moving unit 41 supports the second moving plate 5 so as to be movable in the X direction, and the second moving plate 5 supports the rotation moving unit 43 that rotates the holding unit 10 around an axis parallel to the Z direction. The second moving plate 5 supports the rotation moving unit 43 and the holding unit 10. The rotation moving unit 43 supports the holding unit 10.

[0037] The X-axis moving unit 41 has: a known ball screw that is configured to rotate freely around the axis and moves the second moving plate 5 in the X direction when rotating around the axis; a known pulse motor that rotates the ball screw around the axis; and a known guide rail that supports the second moving plate 5 to move freely in the X direction. The Y-axis moving unit 42 has: a known ball screw that is configured to rotate freely around the axis and moves the moving plate 4 in the Y direction when rotating around the axis; a known pulse motor that rotates the ball screw around the axis; and a known guide rail that supports the moving plate 4 to move freely in the Y direction. The rotation moving unit 43 has a motor that rotates the holding unit 10 around the axis, etc.

[0038] In addition, in the first embodiment, if Figure 3 As shown, in the laser processing device 1, the X-axis moving unit 41 is covered by the X-axis moving unit protection bellows 44 installed on the device body 2 and the second moving plate 5, and the Y-axis moving unit 42 is covered by the Y-axis moving unit protection bellows 45 installed on the device body 2.

[0039] In addition, the laser processing device 1 includes: an X-direction position detection unit (not shown) for detecting the X-direction position of the holding unit 10; a Y-direction position detection unit (not shown) for detecting the Y-direction position of the holding unit 10; and a Z-direction position detection unit (not shown) for detecting the Z-direction position of the condenser lens of the laser beam irradiation unit 20. Each position detection unit outputs a detection result to the controller 100. In the first embodiment, the X-direction position and the Y-direction position of the holding unit 10 of the laser processing device 1 and the Z-direction position of the condenser lens of the laser beam irradiation unit 20 are determined by the distances in the X-direction, the Y-direction, and the Z-direction from a predetermined reference position (not shown).

[0040] The laser beam irradiation unit 20 is a laser beam irradiation unit that focuses a pulsed laser beam 21 on the workpiece 200 held by the holding surface 11 of the holding unit 10 and irradiates the workpiece 200. Figure 1 and Figure 3As shown, a part of the laser beam irradiation unit 20 is arranged at the front end of the support column 6, and the support column 6 is supported by the upright wall 3 erected from the device body 2. The structure of the laser beam irradiation unit 20 will be described later.

[0041] The imaging unit 50 captures the workpiece 200 held by the holding unit 10. The imaging unit 50 has an imaging element such as a CCD (Charge Coupled Device) imaging element or a CMOS (Complementary MOS) imaging element that captures the object opposite to the objective lens in the Z direction. Figure 1 As shown, the photographing unit 50 is disposed at the front end of the supporting column 6 .

[0042] The imaging unit 50 acquires an image captured by the imaging element and outputs the acquired image to the controller 100. In addition, the imaging unit 50 captures an image of the workpiece 200 held by the holding surface 11 of the holding unit 10, and acquires an image for performing alignment (the alignment performs alignment between the workpiece 200 and the laser beam irradiation unit 20).

[0043] The controller 100 controls the above-mentioned components of the laser processing device 1 respectively, so that the laser processing device 1 performs processing on the workpiece 200. The controller 100 is a computer having a processing device, a storage device, and an input / output interface device. The processing device has a microprocessor such as a CPU (central processing unit), and the storage device has a memory such as a ROM (read only memory) or a RAM (random access memory). The processing device of the controller 100 performs processing according to the computer program stored in the storage device, and outputs the control signal for controlling the laser processing device 1 to the above-mentioned components of the laser processing device 1 via the input / output interface device, thereby realizing the function of the controller 100.

[0044] In addition, the laser processing device 1 includes: a display unit as a display member, which is composed of a liquid crystal display device or the like that displays the state and image of the processing operation, and an input unit as an input member, which is used when the operator inputs the processing conditions, etc. The display unit and the input unit are connected to the controller. In the first embodiment, the input unit is composed of a touch panel provided on the display unit.

[0045] Next, the structure of the laser beam irradiation unit 20 will be described. Figure 4 It is schematically shown Figure 1 A perspective view of the structure of a laser beam irradiation unit of a laser processing device shown in FIG. Figure 5 It is schematically shown Figure 4A perspective view of a first lens and the like of a laser beam irradiation unit is shown. Figure 6 It is schematically shown Figure 4 A perspective view of a second lens and the like of a laser beam irradiation unit is shown.

[0046] like Figure 4 As shown in FIG. 1 , the laser beam irradiation unit 20 includes: a laser oscillator 23 as a light source; and a scanning unit 24. The laser oscillator 23 generates a laser beam 21 that converges on the workpiece 200 held by the holding unit 10 and irradiates the workpiece 200. The laser oscillator 23 generates and emits a laser beam 21 having a predetermined wavelength for processing the workpiece 200. In the first embodiment, as shown in FIG. Figure 4 As shown, the laser beam irradiation unit 20 includes a reflection mirror 25 that reflects the laser beam 21 emitted from the laser oscillator 23 toward the scanner 27 of the scanning unit 24 .

[0047] The scanning unit 24 scans the laser beam 21 emitted from the laser oscillator 23 in the X direction perpendicular to the Y direction relative to the workpiece 200 held by the holding unit 10, and irradiates the workpiece 200 with the laser beam 21 by converging the entire length of the predetermined dividing line 203. Figure 4 As shown, the scanning unit 24 has a housing 26 ( Figure 1 as well as Figure 3 As shown), scanner 27, first lens 28 and second lens 29.

[0048] The housing 26 is disposed at the front end of the support column 6 and is a box that accommodates the scanner 27, the first lens 28, and the second lens 29. The housing 26 has an opening formed at the bottom thereof so as to expose the second lens 29 downward.

[0049] The scanner 27 scans the laser beam 21 emitted from the laser oscillator 23 in the X direction. In the first embodiment, the scanner 27 is a multi-faceted scanner having a plurality of reflection mirrors 271 for reflecting the laser beam 21 emitted from the laser oscillator 23. The scanner 27 is supported to be rotatable around a rotation axis 272 parallel to the Y direction, and a plurality of flat reflection mirrors 271 are provided in the circumferential direction of the rotation axis 272. The scanner 27 rotates around the rotation axis 272, as shown in FIG. Figure 5 As shown, the laser beam 21 emitted from the laser oscillator 23 is scanned in the X direction by changing the reflection mirror 25 that reflects the laser beam 21 and the orientation of the reflection mirror 25 .

[0050] The laser beam 21 from the scanner 27 is incident on the first lens 28, and the first lens 28 has a curvature in the X direction so that the laser beam 21 is perpendicular to the workpiece 200 held by the holding unit 10. The first lens 28 is made of a light-guiding material and is a cylindrical lens whose length direction is parallel to the X direction. The length of the first lens 28 in the X direction is set to be greater than the length of the workpiece 200 in the X direction (the outer diameter in the first embodiment) held by the holding unit 10. The width of the first lens 28 in the Y direction is set to be smaller than the length of the workpiece 200 in the Y direction (the outer diameter in the first embodiment) held by the holding unit 10.

[0051] Regarding the first lens 28, the laser beam 21 from the scanner 27 is incident on the first lens 28 from the surface 281 for the laser beam 21 to be incident. Figure 5 As shown, in the front view with the X direction as the left-right direction, the laser beam 21 is emitted from the exit surface 282 curved relative to the X direction, whereby the first lens 28 makes the optical path of the emitted laser beam 21 parallel to the Z direction, thereby making the optical path of the laser beam 21 perpendicular to the workpiece 200 held by the holding unit 10. In this way, in the first lens 28, the exit surface 282 has a curvature in the X direction that makes the laser beam 21 perpendicular to the workpiece 200 held by the holding unit 10.

[0052] The second lens 29 has a curvature in the Y direction for converging the laser beam 21 emitted from the first lens 28 in the Y direction. The second lens 29 is made of a light-guiding material and is a cylindrical lens whose length direction is parallel to the X direction. The length in the X direction is set to be greater than the length in the X direction (in the first embodiment, the outer diameter) of the workpiece 200 held by the holding unit 10. The width in the Y direction of the second lens 29 is set to be smaller than the length in the Y direction (in the first embodiment, the outer diameter) of the workpiece 200 held by the holding unit 10.

[0053] like Figure 6 As shown, regarding the second lens 29, in a front view with the Y direction as the left-right direction, the laser beam 21 from the first lens 28 is incident from a surface 291 curved with respect to the Y direction, and the laser beam 21 is emitted from an emission surface 292 that is parallel to the X direction and the Y direction and flat, thereby converging the emitted laser beam 21 in the Y direction and not converging in the X direction, and irradiating the workpiece 200 held by the holding unit 10. Therefore, the focal point 22 of the laser beam 21 converged by the second lens 29, that is, the scanning unit 24, is formed into an elliptical shape with the major axis parallel to the X direction.

[0054] Thus, the second lens 29 has a curvature in the Y direction that converges the laser beam 21 in the Y direction. In addition, in the first embodiment, the surface 291 of the second lens 29 that is curved with respect to the Y direction and for which the laser beam is incident is located at the top, and the flat exit surface 292 is located at the bottom, and the second lens 29 is located below the first lens 28. In this way, the curved exit surface 282 of the first lens 28 of the scanning unit 24 is opposite to the curved surface 291 of the second lens 29 for which the laser beam is incident. In addition, in the present invention, the orientation of the lenses 28 and 29 is not limited to the orientation described in the first embodiment, and may be opposite to the first embodiment.

[0055] Next, the processing operation of the laser processing device 1 of the first embodiment will be described. In the first embodiment, in the laser processing device 1, the controller 100 receives and registers the processing conditions and the like input by the operator, and places the workpiece 200 on the holding surface 11 of the holding unit 10 positioned in the loading and unloading area. In the first embodiment, in the laser processing device 1, when the controller 100 receives the start instruction of the processing operation from the operator, the workpiece 200 is sucked and held on the holding surface 11 of the holding unit 10 via the adhesive tape 211, and the annular frame 212 is clamped by the clamping portion 12.

[0056] In the first embodiment, the controller 100 of the laser processing device 1 controls the moving unit 40 to move the holding unit 10 to the processing area, and uses the imaging unit 50 to image the workpiece 200 held by the holding unit 10 to perform alignment. In the first embodiment, in the laser processing device 1, according to the processing conditions, the focal point 22 of the laser beam 21 is set on the front surface 202 of the substrate 201, the laser beam irradiation unit 20 is positioned above a predetermined dividing line 203 of the workpiece 200 held by the holding unit 10 by means of the moving unit 40, the laser beam 21 emitted from the laser oscillator 23 is reflected around the rotation axis 272 by the reflection mirror 271 of the scanner 27, the optical path of the laser beam 21 is made parallel to the Z direction by the first lens 28, and the laser beam 21 is converged in the Y direction by the second lens 29, so that the laser beam 21 is scanned on the predetermined dividing line 203. In the first embodiment, in the laser processing device 1, the holding unit 10 is not moved in the X-axis direction with the aid of the X-axis moving unit 41, but the converged laser beam 21 is scanned on the predetermined dividing line 203, and the pulsed laser beam 21 is irradiated from the front side 202 of the substrate 201 over the entire length of the predetermined dividing line 203 of the workpiece 200, and the substrate 201 of the workpiece 200 is ablated along the predetermined dividing line 203.

[0057] In the first embodiment, in the laser processing apparatus 1, when the irradiation of the laser beam 21 to one predetermined dividing line 203 is completed, the controller 100 stops the emission of the laser beam 21 from the laser oscillator 23, controls the Y-axis moving unit 42 to position the laser beam irradiation unit 20 above the other predetermined dividing line 203 of the workpiece 200 held by the holding unit 10, emits the laser beam 21 from the laser oscillator 23, and irradiates the laser beam 21 over the entire length of the predetermined dividing line 203 by scanning or the like using the scanner 27 without moving the holding unit 10 in the X-axis direction by the X-axis moving unit 41. In this way, in the first embodiment, in the laser processing apparatus 1, the laser beam 21 is irradiated over the entire length of all the predetermined dividing lines 203 without moving the holding unit 10 in the X-axis direction by the X-axis moving unit 41, and the workpiece 200 is divided into individual chips 210. In addition, in the laser processing device 1, when irradiating the laser beam 21 to each predetermined dividing line 203, the controller 100 adjusts the rotation speed of the scanner 27 and the repetition frequency of the pulsed laser beam 21 generated by the laser oscillator 23, and appropriately adjusts the overlap rate of the laser beam 21 irradiated to the workpiece 200.

[0058] In the first embodiment, in the laser processing device 1, when the laser beam 21 is irradiated on all the predetermined dividing lines 203, the irradiation of the laser beam 21 is stopped, the controller 100 controls the moving unit 40 to move the holding unit 10 to the loading and unloading area, stops the holding unit 10 from attracting and holding the workpiece 200, and releases the clamping of the annular frame 212 by the clamping part 12.

[0059] The laser processing apparatus 1 of the first embodiment described above includes the scanning unit 24 that scans the laser beam generated by the laser oscillator 23 in the X direction, which is the processing feed direction, with respect to the workpiece held by the holding unit 10. In the laser processing apparatus 1 of the first embodiment, the first lens 28 and the second lens 29 of the scanning unit 24 are set to be longer than the length of the workpiece 200 in the X direction.

[0060] Therefore, in the laser processing device 1 of the first embodiment, the laser beam 21 can be irradiated to the workpiece 200 over the entire length of each planned dividing line 203 without moving the holding unit 10 by the X-axis moving unit 41 during processing feed at a high moving speed. As a result, the laser processing device 1 of the first embodiment has the following effects: thermal expansion during processing can be suppressed, and the position of the focal point 22 of the laser beam 21, that is, the deviation of the processing position can be suppressed.

[0061] In the laser processing apparatus 1 of the first embodiment, the output surface 282 of the first lens 28 of the scanning unit 24 with a large curvature faces the curved surface 291 of the second lens 29 on which the laser beam is incident, so that aberration can be reduced.

[0062] In addition, in the laser processing device 1 of the first embodiment, the focal point 22 of the laser beam 21 is formed into an elliptical shape with the major axis parallel to the X direction. Therefore, the taper of the side of the laser processing groove formed in the processing direction of the X direction is smoother than that of the laser beam 21 whose focal point 22 is circular. Therefore, the flying direction of the debris is farther than the processing point (the point where the laser beam 21 irradiates the workpiece 200), which can prevent the laser processing groove from being buried by the debris.

[0063] [Second embodiment]

[0064] A laser processing device 1 according to a second embodiment will be described with reference to the drawings. Figure 7 It is a perspective view schematically showing a configuration example of a laser processing apparatus according to a second embodiment. Figure 8 yes Figure 7 Another perspective view of the laser processing device shown. Fig. 9 is schematically shown in partial cross section Figure 7 A side view of the structure of a liquid supply unit, etc. of the laser processing device shown. Fig.10 Observed from below Fig. 9 A plan view of the liquid supply unit is shown. Fig.11 is a schematic partial cross-section showing Figure 7 A side view of the laser processing device in the process of over-processing is shown. Figure 7 , Figure 8 , Fig. 9 , Fig.10 as well as Fig.11 The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0065] like Figure 7 , Figure 8 , Fig. 9 and Fig.10 As shown, the laser processing device 1-2 of the second embodiment is the same as the first embodiment except that it has a liquid supply unit 30. The liquid supply unit 30 is arranged between the second lens 29 and the holding unit 10, and supplies liquid (for example, pure water) to at least the area irradiated with the laser beam 21 on the upper surface, that is, the front surface 202, of the workpiece 200 held by the holding unit 10.

[0066] The liquid supply unit 30 includes: a unit body 31, which is mounted on the lower end of the housing 26 of the scanning unit 24 of the laser beam irradiation unit 20 and is formed in a thick flat plate shape; a transmission window 32, which is provided at a position opposite to the second lens 29 in the Z direction; and a liquid supply part 33. Fig. 9 As shown, an opening 34 for allowing the laser beam 21 focused by the second lens 29 to pass through the unit main body 31 is formed at a position opposed to the second lens 29 in the Z direction.

[0067] The transmission window 32 is made of a light-guiding material, is embedded in the opening 34, and transmits the laser beam 21 focused by the second lens 29. In addition, the lower surface 311 of the unit body 31 and the lower surface 321 of the transmission window 32 are formed flat along the horizontal direction, and the lower surface 321 of the transmission window 32 is arranged at a position of about 1 mm or less (for example, several hundred μm) below the lower surface 311 of the unit body 31. In addition, the lower surface 321 of the transmission window 32 is arranged above the front surface 202 of the workpiece 200 held by the holding unit 10 by 0.5 mm or more and 1.0 mm or less.

[0068] The liquid supply unit 33 includes a liquid ejection port 35, a flow path 36, an on-off valve 37, and a liquid supply source 38. The liquid ejection port 35 opens at the lower surface 311 of the unit body 31, and is connected to the liquid supply source 38 via the flow path 36 and the on-off valve 37 provided in the unit body 31. The liquid ejection port 35 is arranged adjacent to the transmission window 32 in the Y direction, that is, formed adjacent to the transmission window 32 in the Y direction. In the second embodiment, as shown in FIG. Fig.10 As shown, a plurality of liquid ejection ports 35 are arranged in the X direction. The flow path 36 gradually inclines with respect to the Z direction and the Y direction in a direction approaching the transmission window 32 as it approaches the liquid ejection port 35 .

[0069] In the laser processing device 1-2 of the second embodiment, when the laser beam 21 is irradiated on the planned dividing line 203, as shown in FIG. Fig.11 As shown in FIG. 1 , the on-off valve 37 is opened to supply the liquid from the liquid supply source 38 from the liquid injection port 35 to the area between the liquid supply unit 30 and the front surface 202 of the workpiece 200 irradiated with the laser beam 21. Then, the flow path 36 is inclined as described above, and a predetermined flow rate is ejected from the liquid injection port 35, so that Fig.11 As indicated by the middle arrow, a flow of the liquid is formed in the Y direction, and the liquid is filled between the liquid supply unit 30 and the area of ​​the front surface 202 of the workpiece 200 irradiated with the laser beam 21 .

[0070] The laser processing device 1-2 of the second embodiment includes a scanning unit 24 that scans the laser beam emitted from the laser oscillator 23 in the X direction, which is the processing feed direction, with respect to the workpiece held by the holding unit 10, and the first lens 28 and the second lens 29 are set to be longer than the length of the workpiece 200 in the X direction. As a result, the laser processing device 1-2 of the second embodiment has the following effect: the laser beam 21 is irradiated to the workpiece 200 over the entire length of each scheduled dividing line 203 without moving the holding unit 10 by the X-axis moving unit 41, and the position of the focusing point 22 of the laser beam 21, that is, the deviation of the processing position can be suppressed.

[0071] In addition, in the laser processing device 1-2 of the second embodiment, the laser beam 21 is irradiated on the workpiece 200 in a state where the space between the front surface 202 of the workpiece 200 and the lower surface 321 of the transmission window 32 is filled with liquid, thereby reducing damage to the workpiece 200 caused by heat generated during processing.

[0072] In the laser processing apparatus 1 - 2 of the second embodiment, ablation processing is performed while supplying liquid to the region of the workpiece 200 irradiated with the laser beam 21 . Therefore, debris generated during ablation processing can be efficiently discharged from the workpiece 200 .

[0073] In the laser processing device 1-2 of the second embodiment, bubbles are generated in the liquid when the laser beam 21 is irradiated. When the generated bubbles are irradiated with the laser beam 21, the bubbles scatter the irradiated laser beam 21, and the laser beam 21 converges to an unexpected area to form a processing mark.

[0074] However, in the laser processing apparatus 1 - 2 of the second embodiment, liquid is ejected from the liquid ejection port 35 from adjacent to the transmission window 32 in the Y direction toward the transmission window 32 to cause bubbles to flow out, thereby removing bubbles from the vicinity of the irradiation area of ​​the laser beam 21 .

[0075] Furthermore, in the laser processing apparatus 1-2 of the second embodiment, the lower surface 321 of the transmission window 32 slightly protrudes from the lower surface 311 of the liquid supply unit 30, so that the position of the lower surface 311 of the liquid supply unit 30 outside the transmission window 32 is higher than the lower surface 321 of the transmission window 32, thereby forming a step. Thus, in the laser processing apparatus 1-2 of the second embodiment, even if bubbles are attached to the lower surface 321 of the transmission window 32, the possibility that the attached bubbles move to the lower surface 311 side of the liquid supply unit 30 and cause the laser beam 21 to irradiate the bubbles can be reduced.

[0076] In addition, in the laser processing device 1-2 of the second embodiment, the focal point 22 of the laser beam 21 is formed into an elliptical shape with a major axis parallel to the X-direction, and the laser beam 21 is irradiated to the workpiece 200 in a state where the space between the front surface 202 of the workpiece 200 and the lower surface 321 of the transmission window 32 is filled with liquid. Therefore, when forming a laser processing groove with the same groove width, the area of ​​the focal point 22 becomes larger than the case of irradiating the laser beam 21 with a circular focal point 22, so the energy density is reduced, and even if the laser beam 21 is irradiated to the bubble to generate scattered light, damage caused by the scattered light is not easy to occur (that is, the workpiece 200 is difficult to be processed by the scattered light).

[0077] In addition, the present invention is not limited to the above-mentioned embodiments and the like. That is, it can be implemented by various deformations within the scope of the main purpose of the present invention. For example, in the present invention, the laser oscillator 23 may emit a laser beam 21 of a wavelength that is transparent to the substrate 201 of the workpiece 200, and the laser processing device 1 or the laser processing device 1-2 may form a modified layer along the predetermined dividing line 203 inside the substrate 201 of the workpiece 200. The modified layer refers to a region where the density, refractive index, mechanical strength, and other physical properties are different from the surrounding physical properties, and examples thereof include a melt processing region, a crack region, an insulation breakdown region, a refractive index change region, and a region where these regions are mixed. The mechanical strength of the modified layer is lower than that of other parts of the substrate 201.

[0078] In the present invention, the first lens 28 and the second lens 29 of the laser processing device 1 are not limited to cylindrical lenses, but may be annular lenses.

Claims

1. A laser processing device, wherein: The laser processing device has: A holding unit that holds the workpiece; a laser oscillator that generates a laser beam that converges and irradiates the workpiece held by the holding unit; an indexing and feeding unit that moves the holding unit holding the workpiece relative to the focal point of the laser beam in the Y direction; and a scanning unit that scans the laser beam emitted from the laser oscillator in an X direction perpendicular to the Y direction relative to the workpiece held by the holding unit, The scanning unit has: a scanner that scans the laser beam emitted from the laser oscillator in the X direction; a first lens, the laser beam from the scanner is incident on the first lens, the first lens having a curvature in the X direction that makes the laser beam perpendicular to the workpiece held by the holding unit; as well as a second lens having a curvature in the Y direction so as to converge the laser beam emitted from the first lens in the Y direction; The first lens and the second lens are respectively set so that the length in the X direction is greater than or equal to the length in the X direction of the workpiece held by the holding unit.

2. The laser processing device according to claim 1, wherein: The scanner is composed of a polygonal scanner having a plurality of reflection mirrors for reflecting the laser beam emitted from the laser oscillator.

3. The laser processing device according to claim 1 or 2, wherein: The laser processing device further comprises a liquid supply unit, which is disposed between the second lens and the holding unit and supplies liquid to at least a region on the upper surface of the workpiece held by the holding unit and irradiated with the laser beam. The liquid supply unit comprises: a transmission window that transmits the laser beam focused by the second lens; and The liquid supply portion has a liquid discharge port formed adjacent to the transmission window in the Y direction.

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