Laser processing apparatus and debris removal apparatus

Abstract

To provide a debris removal device which can sufficiently suction debris scattered with the irradiation of a laser beam.SOLUTION: A debris removal device 38 comprises: an air nozzle 40 which sprays air from one side toward a processing point P where a workpiece 54 is irradiated with a laser beam LB; a suction duct 44 which has a suction opening 42 that suctions debris scattered to the other side by the air sprayed from the air nozzle 40; a vortex generator 46 which is formed on the processing point P side of the suction opening 42 and guides the scattered debris to the suction duct 44; and a C-shaped seal plate 48 which is arranged so as to surround the back of the vortex generator 46 and reduces a gap between the suction opening 42 and the workpiece 54.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus and a debris removal apparatus.

Background Art

[0002] A wafer having a device region in which a plurality of devices such as ICs and LSIs are formed and an outer peripheral surplus region surrounding the device region formed on the surface is divided into individual device chips by a dicing apparatus or a laser processing apparatus, and each of the divided device chips is used in an electric device such as a mobile phone or a personal computer.

[0003] A laser processing apparatus includes at least a holding unit that holds a wafer, a laser irradiation unit that irradiates a laser beam from a condenser onto the wafer held by the holding unit to perform processing, and a feeding unit that relatively feeds the holding unit and the laser irradiation unit for processing, and can process the wafer with high precision (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described laser processing apparatus, a debris suction unit that sucks and removes debris scattered during laser processing is disposed adjacent to the condenser. However, there is a problem that the debris cannot be sufficiently sucked by the debris suction unit and the debris scatters.

[0006] In addition, in a processing apparatus (for example, Japanese Patent Application No. 2020-123201 filed by the applicant on July 17, 2020) that irradiates a laser beam on the boundary between the device region and the outer peripheral surplus region of a wafer to remove the outer peripheral surplus region from the wafer, there are the same problems as described above.

[0007] An object of the present invention is to provide a laser processing apparatus and a debris removing apparatus that can sufficiently suck debris scattered during laser processing.

Means for Solving the Problems

[0008] According to a first aspect of the present invention, the following laser processing apparatus for solving the above problems is provided. That is, 「A laser processing apparatus comprising holding means having a holding surface for holding a workpiece, and laser irradiation means for irradiating a laser beam onto the workpiece held by the holding means to perform processing, The laser irradiation means includes an oscillator that oscillates a laser beam, a condenser that condenses the laser beam oscillated by the oscillator and irradiates the workpiece held by the holding means, and a debris removing apparatus that is disposed adjacent to the condenser and sucks and removes debris generated by the irradiation of the laser beam, The debris removing apparatus includes an air nozzle that blows air from one side toward a processing point where the laser beam is irradiated onto the workpiece, a suction duct having a suction opening that sucks debris scattered to the other side by the air blown from the air nozzle, a vortex generator that is formed on the processing point side of the suction opening and guides the scattered debris to the suction duct, and a C-shaped seal plate that is disposed so as to surround the back of the vortex generator and reduces the gap between the suction opening and the workpiece. A laser processing apparatus」 is provided.

[0009] Preferably, a slit is formed on the side of the seal plate facing the workpiece and on the opposite side of the vortex generator.

[0010] The holding surface of the holding means faces downward, the condenser is disposed below the holding surface, and it is preferable to irradiate the workpiece held by the holding means with a laser beam from below upward.

[0011] The workpiece is a wafer having a device region in which a plurality of devices are partitioned by a dicing line and an outer peripheral surplus region surrounding the device region, and it is desirable that the laser beam is irradiated to the boundary between the device region and the outer peripheral surplus region.

[0012] According to a second aspect of the present invention, there is provided the following debris removal device for solving the above problems. That is, "A holding means having a holding surface for holding a workpiece, and a laser irradiation means for irradiating the workpiece held by the holding means with a laser beam for processing, The laser irradiation means is disposed adjacent to the condenser of a laser processing apparatus including an oscillator that oscillates a laser beam and a condenser that condenses the laser beam oscillated by the oscillator and irradiates the workpiece held by the holding means. A debris removal device, An air nozzle that blows air from one side toward the processing point where the laser beam is irradiated on the workpiece, a suction duct having a suction opening for sucking debris scattered to the other side by the air blown from the air nozzle, and scattered on the processing point side of the suction opening. A vortex generator that guides the debris to the suction duct, and a C-shaped seal plate that is disposed so as to surround the back of the vortex generator and reduces the gap between the suction opening and the workpiece" is provided.

[0013] It is convenient that a slit is formed on the side of the seal plate facing the workpiece and on the opposite side of the vortex generator.

Effect of the Invention

[0014] According to the present invention, debris scattered during laser processing can be effectively guided to the suction duct, and the debris can be sufficiently sucked.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of a laser processing apparatus and a debris removal device configured according to the present invention will be described with reference to the drawings.

[0017] (Laser Processing Apparatus 2) Referring to FIG. 1, a laser processing apparatus indicated as a whole by reference numeral 2 includes holding means 4 having a holding surface for holding a workpiece, and laser irradiation means 6 for irradiating a laser beam onto the workpiece held by the holding means 4 to perform processing.

[0018] (Holding Means 4) The holding means 4 includes an X-axis movable plate 10 mounted on the upper surface of a base 8 so as to be movable in the X-axis direction, a Y-axis movable plate 12 mounted on the upper surface of the X-axis movable plate 10 so as to be movable in the Y-axis direction, a support column 14 fixed to the upper surface of the Y-axis movable plate 12, and a cover plate 16 fixed to the upper end of the support column 14. A long hole 16a extending in the Y-axis direction is formed in the cover plate 16, and a chuck table 18 extending upward through the long hole 16a is rotatably mounted on the upper end of the support column 14.

[0019] The X-axis direction is the direction indicated by arrow X in FIG. 1, and the Y-axis direction is the direction indicated by arrow Y in FIG. 1 and is perpendicular to the X-axis direction. The XY plane defined by the X-axis direction and the Y-axis direction is substantially horizontal.

[0020] At the upper end portion of the chuck table 18, a porous circular suction chuck 20 connected to a suction means (not shown) is arranged. A plurality of clamps 22 are provided at intervals in the circumferential direction on the periphery of the chuck table 18.

[0021] In the holding means 4, by generating a suction force on the upper surface of the suction chuck 20 with the suction means, the workpiece placed on the upper surface of the suction chuck 20 is sucked and held. In this way, the upper surface of the suction chuck 20 serves as a holding surface for holding the workpiece, and the holding surface faces upward.

[0022] Further, the chuck table 18 of the holding means 4 is processed and fed in the X-axis direction by the X-axis feed means 24 and is indexed and fed in the Y-axis direction by the Y-axis feed means 26.

[0023] The X-axis feed means 24 has a ball screw 28 connected to the X-axis movable plate 10 and extending in the X-axis direction, and a motor 30 for rotating the ball screw 28. The X-axis feed means 24 converts the rotational motion of the motor 30 into a linear motion by the ball screw 28 and transmits it to the X-axis movable plate 10, and moves the X-axis movable plate 10 in the X-axis direction along the guide rail 8a on the base 8. Thereby, the chuck table 18 is processed and fed in the X-axis direction.

[0024] The Y-axis feed means 26 has a ball screw 32 connected to the Y-axis movable plate 12 and extending in the Y-axis direction, and a motor 34 for rotating the ball screw 32. The Y-axis feed means 26 converts the rotational motion of the motor 34 into a linear motion by the ball screw 32 and transmits it to the Y-axis movable plate 12, and moves the Y-axis movable plate 12 in the Y-axis direction along the guide rail 10a on the X-axis movable plate 10. Thereby, the chuck table 18 is indexed and fed in the Y-axis direction.

[0025] Further, the chuck table 18 is adapted to be rotated about the vertical axis by a chuck table motor (not shown) built in the column 14.

[0026] (Laser irradiation means 6) The laser irradiation means 6 includes an oscillator (not shown) that oscillates a laser beam, a condenser 36 that condenses the laser beam oscillated by the oscillator and irradiates the workpiece held by the holding means 4, and a debris removal device 38 that is disposed adjacent to the condenser 36 and sucks and removes debris generated by the irradiation of the laser beam.

[0027] As shown in FIG. 1, the laser irradiation means 6 includes a housing 39 that extends upward from the upper surface of the base 8 and then extends substantially horizontally. The oscillator of the laser irradiation means 6 is disposed inside the housing 39, and the condenser 36 is attached to the lower surface of the tip of the housing 39.

[0028] (Debris removal device 38) Referring to FIG. 2 together with FIG. 1, the debris removal device 38 includes an air nozzle 40 that blows air from one side toward the processing point where the laser beam irradiates the workpiece, a suction duct 44 having a suction opening 42 (see FIG. 2) that sucks debris scattered to the other side by the air blown from the air nozzle 40, a vortex generator 46 (see FIG. 2) that is formed on the processing point side of the suction opening 42 and guides the scattered debris to the suction duct 44, and a C-shaped seal plate 48 (see FIG. 2) that is disposed so as to surround the back of the vortex generator 46 and reduces the gap between the suction opening 42 and the workpiece.

[0029] (Air nozzle 40) As shown in FIG. 1, the air nozzle 40 is attached to the lower surface of the tip of the housing 39 and is disposed adjacent to the condenser 36. The air nozzle 40 is connected to an air supply source (not shown) and is adapted to blow the air sent from the air supply source from one side toward the processing point where the laser beam irradiates the workpiece.

[0030] (Suction duct 44) As shown in FIG. 1, the suction duct 44 is attached to the lower surface of the tip of the housing 39 and is disposed on the opposite side of the air nozzle 40 with the condenser 36 interposed therebetween. Further, the suction duct 44 is connected to a suction means (not shown). In the suction duct 44, a suction force is generated at the suction opening 42 by the suction means, and debris scattered to the other side by the air blown from the air nozzle 40 is sucked from the suction opening 42.

[0031] (Vortex generator 46) As shown in FIGS. 2 and 3, a plate-like member 52 extending in the Y-axis direction is bridged over the processing point side of the suction opening 42. As can be understood by referring to FIG. 4, the shape of the cross section (the plane crossing the Y-axis direction) of the plate-like member 52 is arc-shaped. A plurality of triangular vortex generators 46 are provided on the plate-like member 52 at intervals in the Y-axis direction. Further, as shown in FIG. 4, the suction opening 42 is partitioned into an upstream portion 42a and a downstream portion 42b by the plate-like member 52.

[0032] (Seal plate 48) The seal plate 48 is provided in a C shape along the periphery of the suction opening 42. Further, the seal plate 48 is disposed parallel to the holding surface of the holding means 4 (the upper surface of the suction chuck 20). And the seal plate 48 is positioned slightly above (for example, about 2 mm above) the upper surface of the workpiece when the workpiece is irradiated with a laser beam.

[0033] In the illustrated embodiment, a slit 48a is formed on the side of the seal plate 48 facing the workpiece and on the opposite side of the vortex generator 46. As shown in FIGS. 2 and 3, the slit 48a is a depression formed on the lower surface of the seal plate 48 and extends from the inner peripheral edge to the outer peripheral edge of the seal plate 48.

[0034] (Workpiece 54) FIG. 5 shows a workpiece 54 that can be processed by the above-described laser processing apparatus 2. The workpiece 54 shown in FIG. 5(a) is a wafer having a device region 60 in which a plurality of devices 56 are partitioned by a planned division line 58, and an outer peripheral surplus region 62 surrounding the device region 60. In FIG. 5, for convenience, the boundary 64 between the device region 60 and the outer peripheral surplus region 62 is shown by a two-dot chain line, but actually there is no line indicating the boundary 64.

[0035] Note that the workpiece may be a wafer 54' in which a ring-shaped reinforcing portion 66 is formed in a convex shape on the back surface 54b' corresponding to the outer peripheral surplus region 62, as shown in FIG. 5(b).

[0036] Next, a method of performing laser processing on the workpiece 54 using the laser processing apparatus 2 will be described.

[0037] In the illustrated embodiment, first, the surface 54a (the surface on which the device 56 is formed) of the workpiece 54 is turned upward, and the workpiece 54 is placed on the holding surface (the upper surface of the suction chuck 20) of the holding means 4. Next, the suction means connected to the suction chuck 20 is operated to suction-hold the workpiece 54 on the upper surface of the suction chuck 20. Note that it is preferable to previously coat the processed surface of the workpiece 54 with a protective film such as polyvinyl alcohol so that debris does not adhere to the processed surface of the workpiece 54.

[0038] Next, the workpiece 54 is imaged from above by an imaging means (not shown) of the laser processing apparatus 2, and based on the image of the workpiece 54 imaged by the imaging means, the positional relationship between the workpiece 54 and the condenser 36 is adjusted. At this time, the aiming of the laser beam LB is aligned with the processing site to be laser-processed (for example, the planned division line 58), and the height of the focusing point of the laser beam LB is adjusted to the upper surface of the workpiece 54.

[0039] Next, while moving the chuck table 18 so that the condensing point of the laser beam LB sequentially passes through the work areas, a laser beam LB having absorbability is irradiated from the condenser 36 onto the workpiece 54. Thereby, predetermined ablation processing can be performed along the work area (for example, the planned division line 58).

[0040] Naturally, ablation processing may be performed other than on the planned division line 58. For example, when removing the ring-shaped reinforcing portion 66 from the wafer 54', the laser beam LB is irradiated onto the boundary 64 between the device area 60 and the outer peripheral surplus area 62 to perform ablation processing, and a ring-shaped cutting groove can be formed along the boundary 64.

[0041] When performing ablation processing, the air supply source and the suction means of the debris removal device 38 are operated, and air is blown from the air nozzle 40 toward the processing point P in the direction indicated by the arrow F1 in FIG. 4 from one side (the left side in FIG. 4), and a suction force is generated at the suction opening 42 by the suction means. Thereby, the debris generated during ablation processing is scattered to the other side (the right side in FIG. 4) by the air blown from the air nozzle 40, and the scattered debris is sucked into the suction opening 42.

[0042] In the illustrated embodiment, a plate-like member 52 is spanned on the processing point P side of the suction opening 42, and air containing debris is sucked from both the upstream side portion 42a and the downstream side portion 42b of the suction opening 42.

[0043] As described above, since the plate-like member 52 has an arcuate cross-section, the air sucked from the upstream side portion 42a of the suction opening 42 is guided by the upper surface of the plate-like member 52 and sent into the inside of the suction duct 44 as indicated by the arrow F2 in FIG. 4.

[0044] Next, the air sucked from the downstream portion 42b will be described. Since the vortex generator 46 is provided on the lower surface of the plate-like member 52, a turbulent flow T (see Fig. 3) including fine vortices is generated on the downstream side of the vortex generator 46. For this reason, the separation of the flow from the lower surface of the plate-like member 52 is suppressed, and as shown by the arrow F3 in Figs. 3 and 4, the air containing debris easily flows along the lower surface of the plate-like member 52. Therefore, in the illustrated embodiment, by providing the vortex generator 46, the debris scattered from the processing point P can be effectively guided to the suction duct 44.

[0045] When fine vortices are generated on the downstream side of the vortex generator 46, the energy of the air blown from the air nozzle 40 is consumed. Also, as shown in Fig. 4, in the flow indicated by the arrow F3, the flow path on the downstream side of the plate-like member 52 is larger than the flow path on the upstream side of the plate-like member 52. As a result, on the downstream side of the vortex generator 46, the flow velocity of the air blown from the air nozzle 40 is significantly reduced, so that the scattered debris can be easily guided to the suction duct 44.

[0046] During laser processing, in addition to the air blown from the air nozzle 40, the air around the suction opening 42 flows through the space between the upper surface of the workpiece 54 and the lower surface of the seal plate 48 and into the downstream portion 42b of the suction opening 42 (see the arrow F4 in Fig. 3).

[0047] As described above, since the seal plate 48 is positioned close to the upper surface of the workpiece 54 during laser processing, the gap between the suction opening 42 and the workpiece 54 is reduced by the seal plate 48. As a result, the flow velocity of the flow F4 between the seal plate 48 and the workpiece 54 is increased, so that the air (air containing debris) blown from the air nozzle 40 is prevented from leaking out of the suction opening 42.

[0048] Also, in the illustrated embodiment, since the slit 48a is formed on the side of the seal plate 48 facing the workpiece 54 and on the opposite side of the vortex generator 46, the flow rate of the flow F4' passing through the slit 48a among the flow F4 becomes relatively large. As can be understood by referring to FIG. 4, the flow F4' in the slit 48a is a flow opposing the air blown from the air nozzle 40. That is, by providing the slit 48a in the seal plate 48, the flow rate of the flow F4' opposing the air from the air nozzle 40 increases. Therefore, it is more effectively prevented that the air (including debris) blown from the air nozzle 40 leaks out from the suction opening 42.

[0049] As described above, in the illustrated embodiment, the debris scattered from the processing point P by the irradiation of the laser beam LB can be effectively guided to the suction duct 44, and the debris can be sufficiently sucked.

[0050] In the illustrated embodiment, an example in which the laser beam LB is irradiated from above to below the workpiece held by the holding means 4 has been described. However, as shown in FIG. 6, the laser beam LB may be irradiated from below to above the workpiece held by the holding means 4.

[0051] Although FIG. 6 does not show the holding means 4, in the above case, the holding surface of the holding means 4 faces downward, and the holding means 4 sucks and holds the upper surface side of the workpiece in a state where the lower surface side of the workpiece is exposed. Further, the condenser 36 is disposed below the holding surface and positioned at a location away from directly below the processing point P. Thereby, even if the debris generated from the processing point P falls without being sucked, the debris does not adhere to the condenser 36.

Explanation of Reference Numerals

[0052] 2: Laser processing apparatus 4: Holding means 6: Laser irradiation means 36: Condenser 38: Debris removal device 40: Air nozzle 42: Suction opening 44: Suction duct 46: Vortex generator 48: Seal plate 48a: Slit 54: Workpiece 56: Device 58: Planned dividing line 60: Device area 62: Outer peripheral surplus area 64: Boundary LB: Laser beam P: Processing point

Claims

1. A laser processing apparatus comprising: holding means having a holding surface for holding a workpiece; and laser irradiation means for irradiating the workpiece held by the holding means with a laser beam to perform processing, wherein the laser irradiation means includes: an oscillator for oscillating a laser beam; a condenser for condensing the laser beam oscillated by the oscillator and irradiating the workpiece held by the holding means; and a debris removal device disposed adjacent to the condenser for sucking and removing debris generated by the irradiation of the laser beam. The debris removal device includes: an air nozzle for blowing air from one side toward a processing point where the laser beam irradiates the workpiece; a suction duct having a suction opening for sucking debris scattered to the other side by the air blown from the air nozzle; a vortex generator formed on the processing point side of the suction opening for guiding the scattered debris to the suction duct; and a C-shaped seal plate disposed so as to surround the back of the vortex generator for reducing the gap between the suction opening and the workpiece.

2. The laser processing apparatus according to claim 1, wherein a slit is formed on a side of the seal plate facing the workpiece and on the opposite side of the vortex generator.

3. The laser processing apparatus according to claim 1, wherein the holding surface of the holding means faces downward, the condenser is disposed below the holding surface, and the laser beam is irradiated from below upward onto the workpiece held by the holding means.

4. The workpiece is a wafer having a device region in which a plurality of devices are partitioned by a division planned line and an outer peripheral surplus region surrounding the device region, and the laser beam is irradiated onto a boundary between the device region and the outer peripheral surplus region.

5. A laser processing apparatus comprising: holding means having a holding surface for holding a workpiece; and laser irradiation means for irradiating the workpiece held by the holding means with a laser beam to perform processing, wherein the laser irradiation means includes: an oscillator for oscillating a laser beam; a condenser for condensing the laser beam oscillated by the oscillator and irradiating the workpiece held by the holding means; and a debris removal device disposed adjacent to the condenser of the laser processing apparatus. A debris removal device including: an air nozzle that blows air from one side toward a processing point where a laser beam irradiates a workpiece; a suction duct having a suction opening that sucks debris scattered to the other side by the air blown from the air nozzle; a vortex generator formed on the processing point side of the suction opening to guide the scattered debris to the suction duct; and a C-shaped seal plate disposed so as to surround the back of the vortex generator and reduce the gap between the suction opening and the workpiece.

6. The debris removal device according to claim 5, wherein a slit is formed on a side of the seal plate facing the workpiece and opposite to the vortex generator.

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