Laser processing equipment

Abstract

This invention provides a laser processing apparatus that efficiently removes debris from the processing point and prevents debris from adhering to the bottom surface of the housing of a processing nozzle. The laser processing apparatus includes a concentrator and a processing nozzle fixed to the lower part of the concentrator. The processing nozzle has: an upper wall having a laser beam passage; a lower wall connected to the lower part of a portion of the upper wall, containing a debris-catching chamber; a suction port disposed between another portion of the upper wall and the lower wall; a first air jet port disposed on the lower wall, which jets air through the debris-catching chamber in a predetermined direction perpendicular to the optical path of the laser beam passing through the laser beam passage and toward the suction port; and a second air jet port disposed in the lower wall at a position lower than the first air jet port, which jets air through the debris-catching chamber in a predetermined direction and toward the suction port, wherein the flow rate of the air jetted from the second air jet port is smaller than the flow rate of the air jetted from the first air jet port.

Description

Technical Field

[0001] This invention relates to a laser processing apparatus for ablation processing of a workpiece by irradiating it with a laser beam having a wavelength absorbed by the workpiece. Background Technology

[0002] As a method for processing plate-shaped workpieces such as semiconductor wafers, an ablation process is known in which the workpiece is irradiated with a laser beam having a wavelength that is absorbed by the workpiece, causing a portion of the workpiece to sublimate. For example, the focal point of the laser beam is moved relative to the workpiece in a predetermined direction, thereby forming a linear processing groove on the workpiece.

[0003] In ablation processing, processing debris, known as shavings, scatters from the processing point near the focal point. When this debris adheres to the workpiece, the quality of the workpiece deteriorates. Furthermore, when the debris scatters above the processing point, the power of the laser beam reaching the processing point decreases, thus increasing the required processing time.

[0004] Therefore, a laser processing apparatus is proposed in which a laser beam passage that guides the laser beam downward and an air jet outlet that sprays air in a direction perpendicular to the direction of travel of the laser beam are provided on the processing nozzle, so as to remove debris by using air and perform ablation processing on the workpiece (for example, see Patent Documents 1 and 2).

[0005] An opening larger than the laser beam passage is formed on the bottom surface of the nozzle housing, and a suction port for attracting debris is formed at the position facing the air jet port. The space enclosed by the bottom opening, the suction port, and the laser beam passage port functions as a debris-catching chamber to temporarily collect scattered debris.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-77568

[0007] Patent Document 2: Japanese Patent Application Publication No. 2017-35714

[0008] However, when air is ejected from the air jet, the airflow collides with the lower wall of the machining nozzle housing, and the airflow branches in the vertical direction. Sometimes, debris adheres to the bottom side of the lower wall of the machining nozzle along the airflow flowing below the lower wall.

[0009] When debris adheres to the bottom side of the lower wall of the processing nozzle, there is concern that the debris may fall from the bottom side and adhere to the workpiece, causing the quality of the workpiece to deteriorate after processing. Therefore, the frequency of maintenance such as cleaning the processing nozzle increases, which in turn increases the downtime of the laser processing equipment. Summary of the Invention

[0010] The present invention was made in view of this problem and its object is to efficiently remove debris from the processing point and to prevent debris from adhering to the bottom surface of the housing of the processing nozzle.

[0011] According to one aspect of the present invention, a laser processing apparatus is provided for ablation processing of a workpiece held in a chuck table by irradiating it with a laser beam having a wavelength absorbed by the workpiece. The laser processing apparatus comprises: a concentrator having a focusing lens that focuses the laser beam; and a processing nozzle fixed to the lower part of the concentrator, the processing nozzle having: an upper wall having a laser beam passage opening that allows the laser beam focused by the focusing lens to pass toward the workpiece; and a lower wall connected to the lower part of a portion of the upper wall, the lower wall including a debris-catching chamber, the upper part of which is connected to the laser beam passage opening, and the debris-catching chamber having an opening at its lower part. The system includes: a suction port for collecting debris scattered from the workpiece after it has been ablated by the laser beam; a first air jet port for injecting air into the suction port in a predetermined direction perpendicular to the optical path of the laser beam passing through the laser beam through the laser beam port; and a second air jet port for injecting air into the suction port in a predetermined direction across the debris capture chamber, wherein the flow rate of the air injected from the second air jet port is less than the flow rate of the air injected from the first air jet port.

[0012] To prevent the airflow from branching vertically, one could consider reducing the airflow from a single air jet. However, in this case, the airflow would be less effective at discharging debris from the debris capture chamber, potentially reducing the debris discharge performance to the suction port.

[0013] Furthermore, when air is injected by moving the position of a single air nozzle upwards without reducing the airflow rate, the airflow does not branch, so it is assumed that debris no longer adheres to the bottom side of the downward wall. However, in the area near the processing point within the debris trapping chamber, the effect of the air is less pronounced, thus reducing the debris removal performance during laser processing.

[0014] In contrast, one embodiment of the present invention provides a processing nozzle having a first air injection port and a second air injection port located below the first air injection port, wherein the flow rate of air injected from the second air injection port is smaller than the flow rate of air injected from the first air injection port. This prevents debris from adhering to the bottom surface of the downward wall and also prevents a decrease in debris discharge performance. In other words, it achieves a balance between preventing debris adhesion and preventing a decrease in debris discharge performance. Attached Figure Description

[0015] Figure 1 It is a 3D diagram of a laser processing device.

[0016] Figure 2 It is a three-dimensional view of the bottom side of a condenser or similar device.

[0017] Figure 3 It is a partial sectional side view of a condenser or similar device.

[0018] Label Explanation

[0019] 2: Laser processing device; 4: Operation panel; 6: Display device; 8: Box; 10: Box platform; 11: Workpiece; 11a: Front; 11b: Back; 12: Box lift; 14: Push-pull arm; 16: Positioning component; 13: Scribing belt; 15: Frame; 17: Frame unit; 18: First conveying unit; 22: Imaging unit; 19: Debris; 21: Protective film; 23: Laser processing tank; 24: Laser beam irradiation unit; 26: Laser beam forming unit; 28: Processing head; 30: Concentrator; 32: Housing; 34: Through hole; 36: Concentrating lens; 36a: Optical axis; 36b: Cover glass; 38: Tube; 38a: Annular groove; 38b: Flow path; 40: Air supply source; 42: First flow rate adjustment unit; 44: Second flow rate adjustment unit; 46: Third flow rate adjustment unit; 50: Processing nozzle 52: Shell; 52a: Bottom surface; 54: Upper wall; 54a: Upper wall on the +X side; 54b: Upper wall on the -X side; 56: Cavity; 56a: Upper opening; 56b: Lower opening (laser beam passage); 58: Lower wall; 58a: Lower wall on the +X side; 58b: Lower wall on the -X side; 60: Opening; 62: Suction path; 62a: Suction port; 64: Suction source; 66: Debris capture chamber; 70: First cavity 72: Air injection section; 72a: First air injection port; 72b: Flow path; 74: Second air injection section; 76: Pipe section; 76a: Second air injection port; 76b: Flow path; 80: Cleaning section; 82: Pipe section; 82a: Cleaning water supply port; 84: Masking mechanism; 86: Masking plate; 88: Second conveying unit; 90: Coating and cleaning unit; 92: Control section; L: Laser beam; P: Processing point. Detailed Implementation

[0020] An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a 3D view of laser processing device 2. Additionally, in Figure 1 In the diagram, a functional block represents a component of the laser processing device 2.

[0021] Furthermore, the X-axis (machining feed direction, left-right direction), Y-axis (indexing feed direction, front-back direction), and Z-axis (height direction, up-down direction) are mutually perpendicular. An operation panel 4 is provided on the front surface of the laser processing device 2.

[0022] Operators can set processing conditions for the laser processing apparatus 2 by inputting specified information via the control panel 4. A display device 6, such as an LCD screen, is provided on the side of the front surface of the laser processing apparatus 2.

[0023] In the laser processing apparatus 2, the workpiece 11 is subjected to ablation processing. The workpiece 11 is formed, for example, from a semiconductor wafer such as silicon, and multiple predetermined dividing lines (not shown) are arranged in a grid pattern on the front side 11a of the workpiece 11.

[0024] Devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) (not shown) are formed in the regions divided by multiple predefined dividing lines. A circular scribe strip (adhesive tape) 13 formed of resin is attached to the back side 11b of the workpiece 11.

[0025] The diameter of the dicing strip 13 is larger than the diameter of the workpiece 11. The workpiece 11 is attached to the center of the dicing strip 13, and one side of the ring-shaped frame 15 made of metal is attached to the outer periphery of the dicing strip 13.

[0026] The workpiece 11, the dicing strip 13, and the frame 15 constitute a frame unit 17. Multiple frame units 17 are housed in a box 8, which is placed on a rectangular plate-shaped platform 10 located at the front corner of the laser processing device 2.

[0027] A box lift 12 is connected below the box platform 10 to move the box platform 10 up and down. A push-pull arm 14 of the conveying frame unit 17 is provided behind the box platform 10.

[0028] The push-pull arm 14, while holding the frame 15 of the frame unit 17, moves the workpiece 11 from the box 8 before processing. In addition, the push-pull arm 14 moves the processed workpiece 11 into the box 8 by pushing the frame 15.

[0029] A pair of positioning components (guide rails) 16 are provided on both sides of the moving path of the push-pull arm 14. The pair of positioning components 16 adjust the position of the frame unit 17 in the X-axis direction.

[0030] A first conveying unit 18 is provided near a pair of positioning components 16 and a conveying frame unit 17. The first conveying unit 18 has an arm, an adsorption pad provided at one end of the arm, and a rotating mechanism provided at the other end of the arm.

[0031] With the frame 15 adsorbed by the adsorption pad, the first conveying unit 18 uses a rotating mechanism to rotate the arm by a predetermined angle, thereby conveying the frame unit 17 from a pair of positioning parts 16 to the disc-shaped chuck worktable 20.

[0032] The chuck table 20 is arranged adjacent to the box stage 10 and the box lift 12 in the X-axis direction. The chuck table 20 has a disc-shaped frame made of metal.

[0033] A disc-shaped recess (not shown) is formed on the upper surface of the frame, and a disc-shaped porous plate is fixed in the recess. A flow path (not shown) formed inside the frame is connected to the lower surface of the porous plate.

[0034] At the other end of the flow path is a suction source (not shown) such as an ejector. When the suction source is activated, a negative pressure is generated on the upper surface of the porous plate. The upper surface of the frame and the upper surface of the porous plate function as a retaining surface 20a that is approximately flat and coplanar.

[0035] The workpiece 11 is positioned on the holding surface 20a with its front side 11a exposed, and its back side 11b is held by the holding surface 20a across the slitting band 13. At this time, the frame 15 is held by a plurality of clamps 20b provided on the outer periphery of the chuck table 20.

[0036] Below the chuck table 20, a rotary drive source (not shown) is connected to a motor or other means that rotates the chuck table 20 about a predetermined rotation axis that is approximately parallel to the Z-axis direction. Below the rotary drive source, a machining feed unit (not shown) is connected to move the chuck table 20 and the rotary drive source along the X-axis direction.

[0037] The machining feed unit has an X-axis moving stage (not shown) that supports a rotary drive source. The X-axis moving stage is arranged to slide on a pair of X-axis guides (not shown) arranged parallel to the X-axis.

[0038] A ball screw (not shown) is arranged along the X-axis direction between a pair of X-axis guides. A drive source (not shown), such as a pulse motor, is connected to one end of the ball screw to rotate it.

[0039] The nut portion (not shown) located on the lower surface of the X-axis moving stage is rotatably connected to the ball screw. If a drive source such as a pulse motor is used, the chuck table 20 moves along the X-axis direction together with the rotary drive source.

[0040] An imaging unit 22 is provided above the movement path of the chuck table 20, facing the holding surface 20a. The imaging unit 22 has a prescribed optical system including an objective lens, an image sensor, etc., and for example, takes an image of the front 11a side of the workpiece 11 held by the holding surface 20a.

[0041] The image obtained by shooting is displayed, for example, on the display device 6. A laser beam irradiation unit 24 is provided on one side of the shooting unit 22 in the X-axis direction. The laser beam irradiation unit 24 has a laser beam forming unit 26.

[0042] The laser beam forming unit 26 has a laser oscillator (not shown) that oscillates a laser beam. The laser oscillator may, for example, comprise a rod-shaped laser medium formed of Nd:YAG or Nd:YVO4. The laser oscillator may, for example, emit a pulsed laser beam to the outside.

[0043] Additionally, the laser beam forming unit 26 may include, for example, an output adjustment section (not shown) for adjusting the output of the laser beam. The output adjustment section may include, for example, an attenuator. The laser beam forming unit 26 adjusts the laser beam emitted from the laser oscillator to, for example, an average output of 6.0W.

[0044] The laser beam L emitted from the laser oscillator (reference) Figure 2 The laser beam L is a pulsed laser beam with a wavelength (e.g., 355 nm) that is absorbed by the workpiece 11, and the laser beam L is incident on the concentrator 30 of the processing head 28.

[0045] Here, refer to Figure 2 and Figure 3 The structure of the concentrator 30, etc., will be explained. Figure 2 This is a three-dimensional view of the bottom side of the condenser 30, etc. Figure 3 This is a partial cross-sectional side view of the concentrator 30, etc. The concentrator 30 has a rectangular housing 32.

[0046] like Figure 3 As shown, a generally cylindrical through hole 34 is formed in the housing 32. A focusing lens 36 for focusing the laser beam L is fixed at the upper part of the through hole 34. The optical axis 36a of the focusing lens 36 is arranged approximately parallel to the Z-axis direction.

[0047] A disc-shaped cover glass 36b is fixed between the condenser lens 36 and the lower end of the through hole 34. The cover glass 36b allows the laser beam L to pass through. A tube 38 is fixed at the lower part of the housing 32, extending along the Y-axis.

[0048] Air is supplied from the air supply source 40 to the pipe section 38 via the first flow adjustment unit 42. The air supply source 40 includes a compressor that compresses and delivers air, a container for storing compressed air, etc.

[0049] The first flow adjustment unit 42 has a flow adjustment valve (not shown) to adjust the flow rate of air supplied to the pipe 38. An annular groove 38a is formed along the circumference of the inner circumferential side of the housing 32 at a predetermined height position (the inner circumferential side is defined by the through hole 34).

[0050] One end of the flow path 38b is connected to the annular groove 38a, and the tube 38 is connected to the other end of the flow path 38b. Air is supplied to the annular groove 38a via the flow path 38b. Air is injected from the annular groove 38a at, for example, 10 L / min, and the injected air forms a downward airflow.

[0051] The airflow exits to the outside of the housing 52 through the lower opening 56b formed on the housing 52 (described later). This airflow reduces the adhesion of debris such as debris 19 to the cover glass 36b.

[0052] A processing nozzle 50 is fixed to the lower part of the concentrator 30. The processing nozzle 50 has a generally cuboid-shaped housing 52, which is longer than the housing 32 in the X-axis direction. The housing 52 includes an upper wall 54 located at the top. An inverted frustum-shaped cavity 56 is formed in the upper wall 54.

[0053] In addition, Figure 3 In this case, the upper wall 54 located on the +X side of the cavity 56 is designated as the +X side upper wall 54a (a part of the upper wall 54), and the upper wall 54 located on the -X side of the cavity 56 is designated as the -X side upper wall 54b (another part of the upper wall 54).

[0054] The height direction of the cavity 56 is approximately parallel to the Z-axis direction. The position of the housing 52 is adjusted so that the cavity 56 and the through hole 34 are concentric, and the upper opening 56a of the cavity 56 is continuously connected to the lower end of the through hole 34.

[0055] A circular lower opening 56b, with a diameter smaller than that of the upper opening 56a, is located at the lower end of the cavity 56. The lower opening 56b functions as a laser beam passage for the laser beam L, which is focused by the condenser lens 36, to pass through. The laser beam L irradiates the workpiece 11 located below the processing nozzle 50 from the lower opening 56b.

[0056] Relative to the lower opening 56b, a lower wall 58a constituting a lower wall 58 is connected to the lower part of the upper wall 54a on the +X side. Figure 3 For convenience, the boundary between the upper wall 54a and the lower wall 58a on the +X side is shown by dashed lines, but the upper wall 54a and the lower wall 58a on the +X side are formed integrally.

[0057] Relative to the lower opening 56b, a -X side lower wall 58b constituting the lower wall 58 is disposed on the side opposite to the +X side lower wall 58a and opposite to the -X side upper wall 54b. An opening 60 is formed in a portion of the lower part of the lower wall 58 for taking in debris 19 that flies out from the workpiece 11 during the ablation process.

[0058] like Figure 2 As shown, when viewed from the bottom surface 52a side of the housing 52, the opening 60 has a roughly pentagonal shape. Furthermore, an attraction path 62 for attracting debris 19 and the like is formed between the upper wall 54b on the -X side and the lower wall 58b on the -X side.

[0059] The suction port 62a is located at the +X side end of the suction path 62, and a suction source 64, such as an injector, is connected to the -X side end of the suction path 62. The suction source 64 sets the suction path 62 to a specified gauge pressure, for example, between -10 kPa and -1 kPa, thereby drawing debris 19 and the like from the suction port 62a.

[0060] The space enclosed by the lower opening 56b, the opening 60, the side of the lower wall 58a on the -X side, and the suction port 62a functions as a debris-catching chamber 66. During the ablation process, debris 19 scattered from the workpiece 11 is taken into the debris-catching chamber 66 through the opening 60 and then attracted to the suction path 62.

[0061] In addition, the upper part of the debris-catching chamber 66 is connected to the lower opening 56b, and a part of the debris-catching chamber 66 also has the function of allowing the laser beam L emitted from the lower opening 56b to pass toward the workpiece 11.

[0062] A first air injection unit 70 is provided in the lower wall 58a on the +X side. The first air injection unit 70 has a pipe 72 that extends along the Y-axis and is connected to the housing 52. Air is supplied from the air supply source 40 to the pipe 72 via the second flow adjustment unit 44.

[0063] The second flow adjustment unit 44 has a flow adjustment valve to adjust the flow rate of air supplied to the pipe section 72. A first air injection port 72a is formed on the side of the debris capture chamber 66 on the +X side lower wall 58a (i.e., the surface on the -X side).

[0064] Air is supplied from the tube 72 to the first air injection port 72a via a flow path 72b formed on the lower wall 58a of the +X side along the X-axis direction. The first air injection port 72a has an elongated orifice shape that is wide in the Y-axis direction when viewed along the X-axis direction.

[0065] The first air jet 72a has a width of approximately 2.5 mm in the Y-axis direction and a width of 1.0 mm in the Z-axis direction, for example. The first air jet 72a jets air toward the suction port 62a in a manner that traverses the debris-catching chamber 66 in the X-axis direction (prescribed direction) perpendicular to the optical path of the laser beam L passing through the lower opening 56b.

[0066] By injecting air from a first air jet 72a that is wide in the Y-axis direction, the adhesion of debris 19 to the cover glass 36b can be reduced more reliably compared to using a first air jet 72a that is narrow in the Y-axis direction.

[0067] A second air injection unit 74 is provided in the lower wall 58a on the +X side below the first air injection unit 70. The second air injection unit 74 has a pipe 76 extending along the Y-axis and connected to the housing 52. Air is supplied from the air supply source 40 to the pipe 76 via the third flow adjustment unit 46.

[0068] The third flow adjustment unit 46 has a flow adjustment valve to adjust the flow rate of air supplied to the pipe section 76. Below the first air injection port 72a, a second air injection port 76a is formed on the side of the debris capture chamber 66 on the -X side of the lower wall 58a on the +X side.

[0069] Air is supplied from the tube 76 to the second air injection port 76a via a flow path 76b formed on the lower wall 58a of the +X side along the X-axis direction. The second air injection port 76a has a circular shape when viewed along the X-axis direction.

[0070] The second air injection port 76a has, for example, a diameter of about 1.5 mm. However, the second air injection port 76a may also have the same elongated orifice shape as the first air injection port 72a. The center of the second air injection port 76a is located below the center of the first air injection port 72a at a predetermined distance.

[0071] For example, the first distance from the center of the first air injection port 72a to the opening 60 is adjusted to a specified value that is more than 1.05 times and less than 3.34 times the second distance from the center of the second air injection port 76a to the opening 60 (i.e., 1.05 ≤ first distance / second distance ≤ 3.34).

[0072] The second air jet 76a, like the first air jet 72a, jets air toward the suction port 62a in a manner that traverses the debris capture chamber 66 in the X-axis direction (a predetermined direction). In this embodiment, the flow rate of the air jetted from the second air jet 76a is smaller than the flow rate of the air jetted from the first air jet 72a.

[0073] The air flow rate from the second air injection port 76a is adjusted to be less than 1 / 2, 1 / 3, or 1 / 4 of the air flow rate from the first air injection port 72a. For example, air is injected from the first air injection port 72a at a specified value of 70 L / min or more and 100 L / min or less, and air is injected from the second air injection port 76a at a specified value of 20 L / min or more and 30 L / min or less.

[0074] The debris 19 taken into the debris capture chamber 66 is drawn into the suction port 62a by air assisted from the first air jet port 72a and the second air jet port 76a, and then discharged from the processing head 28.

[0075] In this way, the debris capture chamber 66, the suction port 62a, the first air jet port 72a, and the second air jet port 76a function as debris removal units that attract and remove debris 19.

[0076] Here, as a comparative example, consider the case where an air jet port is provided on the lower wall 58a on the +X side. In this case, when air is injected at a specified flow rate to reliably propel the debris 19 taken into the debris capture chamber 66 toward the suction port 62a, there is a possibility that the airflow will collide with the lower wall 58b on the -X side.

[0077] When the airflow collides with the lower wall 58b on the -X side, the airflow branches in the vertical direction, and sometimes the debris 19 adheres to the bottom surface 52a side of the lower wall 58b on the -X side (e.g., the opening and closing device 86 described later) along the airflow flowing below the lower wall 58.

[0078] In contrast, if the airflow from one air jet is lower than the specified flow rate in order to prevent debris 19 from adhering to the bottom surface 52a of the lower wall 58b on the -X side, the airflow may not be able to act on the debris 19 in the debris capture chamber 66, and the discharge performance of debris 19 to the suction port 62a may be reduced.

[0079] Furthermore, when the position of one air jet is moved upwards to inject air at a predetermined flow rate without causing the airflow to branch vertically, the airflow does not branch, and therefore it is assumed that the debris 19 no longer adheres to the bottom surface 52a of the lower wall 58b on the -X side. However, in the region near the processing point P in the debris trapping chamber 66, the effect of the air is difficult to exert. Therefore, in this case, the debris removal performance during laser processing is reduced.

[0080] In contrast, in this embodiment, a first air injection port 72a and a second air injection port 76a located below the first air injection port 72a are provided in the processing nozzle 50, and the flow rate of the air injected from the second air injection port 76a is smaller than the flow rate of the air injected from the first air injection port 72a.

[0081] Therefore, it is possible to prevent the debris 19 from adhering to the bottom surface 52a of the -X side lower wall 58b, and also to prevent a decrease in the debris 19's discharge performance. That is, it is possible to both prevent the adhesion of the debris 19 and prevent a decrease in the debris 19's discharge performance. Therefore, the debris 19 can be efficiently removed from the processing point P, and the adhesion of the debris 19 to the bottom surface 52a of the -X side lower wall 58b can be suppressed.

[0082] A cleaning section 80 is provided at the bottom of the upper wall 54b on the -X side and near the suction port 62a. The cleaning section 80 has a pipe section 82 that extends along the Y-axis and is connected to the housing 52. Cleaning water, such as pure water, is supplied to the pipe section 82 via a fourth flow adjustment unit (not shown).

[0083] The fourth flow adjustment unit has a flow adjustment valve to adjust the flow rate of the cleaning water supplied to the pipe section 82. A cleaning water supply port 82a is formed on the bottom surface of the upper wall 54b on the -X side. The cleaning water is used when cleaning the debris capture chamber 66 after laser processing.

[0084] A cover mechanism 84 for opening and closing the opening 60 is provided on the bottom surface 52a of the lower wall 58. Additionally, Figure 2 For convenience, the cover mechanism 84 is omitted. The cover mechanism 84 includes a cover 86 having a sufficient area to cover the opening 60.

[0085] The mask 86 can be moved along the X-axis by a mask moving device (not shown). The mask mechanism 84 moves the mask 86 towards the -X side during laser processing to open the opening 60, and moves the mask 86 towards the +X side after laser processing to close the opening 60.

[0086] Here, return Figure 1The other components of the laser processing apparatus 2 will be described below. The laser beam irradiation unit 24 is connected to the Y-axis and Z-axis moving mechanism (not shown). The laser beam irradiation unit 24 can move in the Y-axis and Z-axis directions via the Y-axis and Z-axis moving mechanism.

[0087] In addition, in the laser processing apparatus 2, if the chuck table 20 is configured to move in both the X-axis and Y-axis directions, a Z-axis moving mechanism (not shown) can be connected to the laser beam irradiation unit 24 to move the laser beam irradiation unit 24 in the Z-axis direction.

[0088] A second conveying unit 88 of the conveying frame unit 17 is provided behind the chuck worktable 20 (on the +Y side). A coating and cleaning unit 90 is provided below the second conveying unit 88.

[0089] The coating and cleaning unit 90 has a rotary table (not shown) with an attraction and holding frame unit 17. A cleaning nozzle (not shown) is provided above the rotary table to spray cleaning water such as pure water toward the holding surface of the rotary table.

[0090] A resin coating nozzle (not shown) is provided at a different location from the cleaning nozzle, spraying water-soluble resin toward the retaining surface. The water-soluble resin is polyvinyl alcohol, ethylene glycol, etc.

[0091] After applying a water-soluble resin to the front surface 11a of the workpiece 11, the water-soluble resin is dried, thereby forming a water-soluble protective film 21 on the front surface 11a (see reference). Figure 3 By forming a protective film 21, it is possible to prevent debris 19 from adhering directly to the front side 11a.

[0092] Furthermore, after laser processing, the rotary table is rotated while cleaning water is being sprayed from the cleaning nozzle onto the front side 11a, thereby removing the protective film 21. This allows both the protective film 21 and debris 19 to be removed from the front side 11a.

[0093] The actions of the box lift 12, push-pull arm 14, positioning component 16, first conveying unit 18, chuck worktable 20, shooting unit 22, laser beam irradiation unit 24, second conveying unit 88, coating and cleaning unit 90, etc. are controlled by the control unit 92.

[0094] The control unit 92 may be composed of, for example, a computer, which includes: a processor (processing device) represented by a CPU (Central Processing Unit); main storage devices such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), and ROM (Read Only Memory); and auxiliary storage devices such as flash memory, hard disk drives, and solid-state drives.

[0095] The auxiliary storage device stores software containing prescribed programs. The control unit 92 functions by operating the processing device and the like according to the software. The control unit 92 automatically performs laser processing on the workpiece 11.

[0096] Next, the sequence of laser processing will be explained. First, the frame unit 17 is moved out of the box 8 using the push-pull arm 14, etc. Then, the frame unit 17 is moved to the coating and cleaning unit 90 using the first conveying unit 18.

[0097] Then, a protective film 21 is formed on the front side 11a using the coating and cleaning unit 90 (protective film forming process). After the protective film forming process, the frame unit 17 is transferred to the chuck table 20 using the first transfer unit 18.

[0098] The back side 11b is held in place by attraction using the holding surface 20a. Then, the imaging unit 22 and the like are used to align the pre-defined dividing line approximately parallel to the X-axis direction. In addition, the area directly below the lower opening 56b is positioned on an extension line of the pre-defined dividing line.

[0099] Then, while irradiating the laser beam L with the focal point positioned near the front surface 11a, the chuck table 20 and the machining head 28 are fed relative to each other along the X-axis. The front surface 11a of the workpiece 11 is ablated along the path of the focal point to form a laser machining groove 23 (see reference). Figure 3 ).

[0100] After ablation of the workpiece 11 along all predetermined dividing lines in one direction, the chuck table 20 is rotated 90 degrees. Then, ablation of the workpiece 11 is performed similarly along all predetermined dividing lines in another direction perpendicular to one direction (laser processing step).

[0101] Typically, when ablation is performed on both the workpiece 11 and the protective film 21, the debris 19 tends to adhere to the bottom surface 52a of the lower wall 58b on the -X side, compared to when ablation is performed only on the workpiece 11 without the protective film 21.

[0102] However, in this embodiment, as described above, it is possible to prevent the debris 19 from adhering to the bottom surface 52a of the lower wall 58b on the -X side, and it is also possible to prevent a decrease in the removal performance of the debris 19. Therefore, even when the workpiece 11 with the protective film 21 is subjected to ablation processing, the adhesion of the debris 19 to the bottom surface 52a can be reduced. Therefore, the debris 19 can be efficiently removed from the processing point P, and the adhesion of the debris 19 to the bottom surface 52a can be suppressed.

[0103] After the laser processing step, the second transfer unit 88 transfers the frame unit 17 from the chuck table 20 to the coating and cleaning unit 90, using the holding surface of the rotating table to hold the back side 11b of the workpiece 11.

[0104] In the coating and cleaning unit 90, while the rotary table is rotating, cleaning water is sprayed from the cleaning nozzle toward the front side 11a of the workpiece 11. This removes debris 19 and the protective film 21 through cleaning. Then, the spraying of cleaning water from the cleaning nozzle is stopped, and the rotary table is rotated to dry the workpiece 11 (cleaning and drying process).

[0105] After the cleaning and drying process, the first conveying unit 18, the push-pull arm 14, etc., move the frame unit 17 into the box 8. Furthermore, the structure and method of the above-described embodiments can be appropriately modified and implemented without departing from the scope of the present invention.

Claims

1. A laser processing apparatus, which performs ablation processing by irradiating a workpiece held in a chuck table with a laser beam having a wavelength absorbed by the workpiece, characterized in that, This laser processing device has the following features: A concentrator having a focusing lens that focuses the laser beam; and The processing nozzle is fixed to the lower part of the concentrator. The processing nozzle has the following characteristics: The upper wall is provided with a laser beam passage, which allows the laser beam focused by the condensing lens to pass towards the workpiece. The lower wall is connected to the lower part of a portion of the upper wall. The lower wall includes a debris-catching chamber. The upper part of the debris-catching chamber is connected to the laser beam through an opening. The debris-catching chamber has an opening at the lower part, which is used to collect debris scattered from the workpiece after it has been ablated by the laser beam. A suction port, located between another portion of the upper wall and the lower wall, is used to suction the debris taken into the debris-catching chamber from the opening; The first air jet is disposed on the lower wall, and the first air jet injects air toward the suction port in a predetermined direction perpendicular to the optical path of the laser beam passing through the laser beam through the laser beam through the port, from the side of the debris capture chamber away from the suction port. as well as The second air jet is disposed in the lower wall at a position lower than the first air jet, and the second air jet injects air toward the suction port in a predetermined direction, traversing the debris capture chamber from the side away from the suction port. The flow rate of air ejected from the second air nozzle is smaller than the flow rate of air ejected from the first air nozzle.

Images