JP2018182002A - Processing method for workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method for a workpiece capable of appropriately detecting a key pattern of a device even after the workpiece is irradiated with a laser beam and processed.SOLUTION: The present invention relates to a processing method for a workpiece including: a protective film forming step of forming a protective film by coating a surface of the workpiece with a liquid-state resin; an alignment step of imaging a region including a key pattern of a device over the protective film, detecting the key pattern and calculating a position of a predetermined dividing line; a processing step of irradiating the workpiece with a laser beam of a wavelength having absorptivity, and forming a calf along the predetermined dividing line; a debris removing step of injecting a gas to a surface side of the workpiece to remove debris deposited on the protective film; a key pattern detecting step of imaging the region including the key pattern over the protective film and detecting the key pattern; and a discrimination and notification step of determining whether a distance between the detected key pattern and the calf falls within a preset range, and issuing a notification in a case where the distance is out of the range.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a processing method for processing a plate-like workpiece.

  Before dividing a wafer or the like on which a functional layer composed of a low-k film or metal film is provided on the entire surface side into a plurality of chips, a portion overlapping the planned dividing line (street) of this functional layer It is often removed by laser ablation. This can prevent peeling or chipping of the functional layer during division.

  By the way, in the above-mentioned laser ablation, since a part of a workpiece is melted and sublimated by a laser beam, a large amount of debris (machining debris) is generated. Since this debris can not be easily removed if it adheres to the workpiece, the surface side of the workpiece is covered in advance with a water-soluble protective film or the like to prevent debris from adhering (for example, Patent Documents 1, 2 etc. reference).

JP 2004-322168 A JP 2005-150523 A

  In recent years, the opportunity to cut a workpiece such as a semiconductor wafer only by laser ablation has also increased. However, in such a case, the amount of the workpiece to be melted and sublimated is larger than in the case where only the surface side of the workpiece is removed, so the amount of debris also increases accordingly. That is, the amount of debris attached to the protective film also increases.

  As a result, the characteristic pattern (key pattern) in the device can not be appropriately imaged from the surface side of the workpiece, which affects the process of using the image (captured image) obtained by imaging. For example, if the key pattern in the device can not be imaged properly, the positional relationship between the formed kerf (cut) and the key pattern is also unknown, so it can not be determined whether the kerf is formed at an appropriate position, Machining accuracy tends to be low.

  The present invention has been made in view of such problems, and the object of the present invention is to process a workpiece capable of appropriately detecting a key pattern of a device even after the workpiece is irradiated with a laser beam and processed. It is to provide a method.

  According to one aspect of the present invention, there is provided a method of processing a workpiece, in which a workpiece having a device formed in each of the regions on the surface side partitioned by the intersecting planned dividing lines is processed. A protective member attaching step of attaching a protective member on the back surface, a protective film forming step of forming a protective film by coating a liquid resin on the surface of the workpiece to which the protective member is attached; An area including a key pattern which is a characteristic pattern is imaged through the protective film, the key pattern is detected from the obtained captured image, and the position of the planned dividing line at a predetermined distance from the key pattern is determined. An alignment step, and a position of the dividing line determined in the alignment step is irradiated with a laser beam of a wavelength having an absorbability to the workpiece, and the dividing line A processing step of forming a kerf along the surface, a debris removal step of injecting a gas to the surface side of the workpiece, and removing debris attached to the protective film in the processing step; an area including the key pattern; Is a key pattern detection step of imaging through the protective film from which debris has been removed and detecting the key pattern from the obtained imaged image, and whether the distance between the detected key pattern and the kerf is within a preset range It is determined whether or not it is determined, and when it is out of the range, there is provided a method of processing a workpiece including a determination informing step of notifying an operator.

  In one aspect of the present invention, the protective film may be formed by spin coating the liquid resin on the surface of the workpiece. In addition, in the key pattern detection step, the area including the key pattern and the kerf may be imaged, and the position of the kerf may be further detected from the acquired captured image.

  In the method of processing a workpiece according to an aspect of the present invention, a laser beam of a wavelength having absorption to the workpiece is irradiated to form a kerf along the planned dividing line, and then the surface side of the workpiece is processed. Since the gas is jetted to remove the debris attached to the protective film, the area including the key pattern can then be imaged over the protective film from which the debris has been removed, and the key pattern can be appropriately detected from the captured image obtained.

  That is, according to the method for processing a workpiece according to an aspect of the present invention, the key pattern of the device can be appropriately detected even after the workpiece is irradiated with the laser beam and processed. Therefore, when the distance between the detected key pattern and the kerf is not within the preset range, it is possible to prevent the processing accuracy from being lowered by notifying the operator of the fact.

FIG. 1A is a perspective view for describing the protective member attaching step, and FIG. 1B is a cross-sectional view for describing the protective member attaching step. It is a perspective view which shows the structural example of a laser processing apparatus typically. FIG. 3A is a side view partially in section for explaining the protective film forming step, and FIG. 3B is a sectional view for explaining the protective film forming step. FIG. 4 (A) is a partial cross-sectional side view for explaining the alignment step, and FIG. 4 (B) is an example of an image obtained in the alignment step. FIG. 5 (A) is a partial cross-sectional side view for explaining the processing step, and FIG. 5 (B) and FIG. 5 (C) are cross-sectional views for explaining the processing step. FIG. 6 (A) is a partial cross-sectional side view for describing the debris removal step, and FIG. 6 (B) is a cross-sectional view for describing the debris removal step. FIG. 7A is a partial cross-sectional side view for explaining the key pattern detection step, and FIG. 7B is an example of an image obtained in the key pattern detection step. It is a partial cross section side view for explaining the debris removal step concerning a modification.

  Embodiments according to one aspect of the present invention will be described with reference to the attached drawings. The processing method of the to-be-processed object concerning this embodiment is a protection member sticking step (refer FIG. 1 (A) and FIG. 1 (B)), a protective film formation step (refer FIG. 3 (A) and FIG. Alignment step (see FIGS. 4A and 4B), processing step (see FIGS. 5A, 5B, and 5C), debris removal step (FIG. 6 (FIG. 6A)). A) and FIG. 6 (B)), a key pattern detection step (refer to FIG. 7 (A) and FIG. 7 (B)), and a judgment informing step.

  In the protective member attaching step, the protective member is attached (adhered) to the back surface of the workpiece. In the protective film formation step, a liquid resin is coated on the surface of the workpiece to form a protective film. In the alignment step, the device provided on the surface side of the workpiece is imaged through the protective film, the key pattern is detected from the obtained image, and the position of the planned dividing line is determined from the position of the key pattern.

  In the processing step, a laser beam of an absorptive wavelength is irradiated to the workpiece to form a groove (kerf) along the planned dividing line. In the debris removal step, a gas is injected to the surface side of the workpiece to remove debris attached to the protective film. In the key pattern detection step, an area including the key pattern is imaged over the protective film, and the key pattern is detected from the obtained image.

  In the determination notification step, it is determined whether or not the distance between the detected key pattern and the groove is within a preset range, and if it is not within the range (if it is out of the range), that is notified to the operator. Hereinafter, the processing method of the to-be-processed object which concerns on this embodiment is explained in full detail.

  In the method of processing a workpiece according to the present embodiment, first, a protection member sticking step of sticking a protection member on the back surface of the workpiece is performed. FIG. 1A is a perspective view for describing the protective member attaching step, and FIG. 1B is a cross-sectional view for describing the protective member attaching step.

  As shown to FIG. 1 (A), the to-be-processed object 11 processed by this embodiment is a disk shaped wafer which consists of semiconductor materials, such as silicon, for example. The surface 11 a side of the workpiece 11 is divided into a plurality of areas by a plurality of planned dividing lines (streets) 13 intersecting each other, and in each area, a device 15 such as an IC (Integrated Circuit) is formed. ing. Each device 15 includes a key pattern which is a characteristic pattern.

  Further, as shown in FIG. 1B, on the surface 11 a side of the workpiece 11, a metal film functioning as a wire of the device 15 described above, a metal film forming a TEG (Test Elements Group), and a wire The functional layer 17 is formed by laminating an insulating film (typically, a low-k film) or the like that insulates. The surface of the functional layer 17 is exposed on the surface 11 a side of the workpiece 11.

  In the present embodiment, a disk-shaped wafer made of a semiconductor material such as silicon is used as the workpiece 11, but the material, shape, structure, size and the like of the workpiece are not limited. For example, a workpiece made of another semiconductor, ceramic, resin, metal or the like can also be used. Further, there is no limitation on the type, number, shape, structure, size, arrangement, etc. of the device 15 and the functional layer 17.

  In the protective member attaching step, as shown in FIGS. 1A and 1B, the protective member 21 is attached to the back surface 11b side of the workpiece 11. The protective member 21 is, for example, a circular resin film (sheet, tape) having a diameter larger than that of the workpiece 11. On one surface of the protective member 21, an adhesive layer (adhesive material layer) having adhesive strength is provided. There is.

  Therefore, the protective member 21 can be attached to the back surface 11 b of the workpiece 11 by bringing one surface of the protective member 21 into close contact with the back surface 11 b of the workpiece 11. By attaching the protective member 21 to the workpiece 11, the impact applied to the workpiece 11 can be alleviated and the devices 15 and the like on the surface 11a side can be protected. The material, shape, structure, size, etc. of the protective member 21 are not limited. In addition, an annular frame 23 made of metal such as aluminum is fixed to the outer peripheral portion of the protective member 21.

  After the protective member attaching step, the surface 11a of the workpiece 11 is covered with a liquid resin to form a protective film forming step. FIG. 2: is a perspective view which shows typically the example of a structure of the laser processing apparatus 2 used for each step after a protective film formation step. In addition, in FIG. 2, the one part component of the laser processing apparatus 2 is shown by the functional block.

  As shown in FIG. 2, the laser processing apparatus 2 includes a base 4 that supports each component. A support structure 6 extending in the Z-axis direction (vertical direction) is provided at the rear end of the base 4. An upwardly projecting protrusion 4 a is provided at a front corner of the base 4 remote from the support structure 6.

  A space is formed inside the projecting portion 4a, and in this space, a cassette elevator 8 which moves up and down is provided. On the upper surface of the cassette elevator 8, a cassette 10 capable of containing a plurality of workpieces 11 is placed. In addition, the workpiece | work 11 is accommodated in the cassette 10 in the state supported by the cyclic | annular flame | frame 23 via the protection member 21 after the protection member sticking step mentioned above.

  At a position adjacent to the protruding portion 4 a, an alignment unit 12 for aligning the rough position of the frame 23 supporting the workpiece 11 is disposed. The alignment unit 12 includes, for example, a pair of guide rails which are approached and separated while maintaining a state parallel to the X-axis direction (process feed direction). Each guide rail has a support surface for supporting the frame 23 and a side surface perpendicular to the support surface.

  For example, the frame 23 taken out of the cassette 10 is placed on the guide rails of the alignment unit 12, and the frame 23 is held in the Y-axis direction (indexing feed direction) by the guide rails to align the frame 23 at a predetermined position. Can. Above the alignment unit 12, a transport unit 14 for transporting the frame 23 (workpiece 11) is disposed.

  At a position adjacent to the cassette elevator 8 and the alignment unit 12, a spin coater 16 for spin-coating a liquid resin is provided. The spin coater 16 includes a spinner table 18 for holding the workpiece 11. The spinner table 18 is connected to a rotational drive source (not shown) such as a motor, and rotates about a rotational axis substantially parallel to the Z-axis direction.

  The upper surface of the spinner table 18 is a holding surface 18 a (see FIG. 3A) for holding the workpiece 11. The holding surface 18a is formed substantially in parallel to the X-axis direction and the Y-axis direction, and a suction source is provided via a suction passage 18b (see FIG. 3A) or the like formed inside the spinner table 18. It is connected to (not shown).

  Further, around the spinner table 18, four clamps 18c (see FIG. 3A) for fixing the frame 23 supporting the workpiece 11 from four directions are provided. Above the spinner table 18, a nozzle 20 for dropping a liquid resin, which is a raw material of a protective film, toward the workpiece 11 is disposed.

  At the center of the base 4, a moving mechanism (processing feed mechanism, indexing feed mechanism) 22 is provided. The moving mechanism 22 includes a pair of Y-axis guide rails 24 disposed on the upper surface of the base 4 and parallel to the Y-axis direction. A Y-axis moving table 26 is slidably attached to the Y-axis guide rail 24.

  A nut portion (not shown) is provided on the back surface side (lower surface side) of the Y-axis moving table 26, and a Y-axis ball screw 28 parallel to the Y-axis guide rail 26 is screwed into this nut portion. There is. A Y-axis pulse motor 30 is connected to one end of the Y-axis ball screw 28. When the Y-axis ball screw 28 is rotated by the Y-axis pulse motor 30, the Y-axis moving table 26 moves in the Y-axis direction along the Y-axis guide rail 24.

  A pair of X axis guide rails 32 parallel to the X axis direction are provided on the surface (upper surface) of the Y axis moving table 26. An X-axis moving table 34 is slidably attached to the X-axis guide rail 32.

  A nut portion (not shown) is provided on the back surface side (lower surface side) of the X-axis movement table 34, and an X-axis ball screw 36 parallel to the X-axis guide rail 32 is screwed into this nut portion. There is. An X-axis pulse motor (not shown) is connected to one end of the X-axis ball screw 36. When the X axis ball screw 36 is rotated by the X axis pulse motor, the X axis moving table 34 moves in the X axis direction along the X axis guide rail 32.

  A table base 38 is provided on the front surface side (upper surface side) of the X-axis moving table 34. A chuck table 40 for holding the workpiece 11 is disposed above the table base 38. The chuck table 40 is connected to a rotational drive source (not shown) such as a motor via a table base 38, and rotates around a rotational axis substantially parallel to the Z-axis direction (vertical direction). The chuck table 40 and the table base 38 are moved in the X-axis direction and the Y-axis direction by the above-described moving mechanism 22 (processing feed, index feed).

  The upper surface of the chuck table 40 is a holding surface 40 a for holding the workpiece 11. The holding surface 40a is formed substantially parallel to the X-axis direction and the Y-axis direction, and a suction source (not shown) is formed through the suction path 40b (see FIG. 5A etc.) formed inside the chuck table 40. (Shown). Further, around the chuck table 40, four clamps 42 for fixing an annular frame 23 supporting the workpiece 11 from four directions are provided.

  The support structure 6 is provided with a support arm 6a protruding from the surface (front surface), and a laser irradiation unit 44 for emitting a laser beam downward is disposed at the tip of the support arm 6a. . Further, at a position adjacent to the laser irradiation unit 44, an imaging unit (camera) 46 for imaging the upper surface side (surface 11a side) of the workpiece 11 is provided. In the vicinity of the laser irradiation unit 44 and the imaging unit 46, a nozzle 48 (see FIG. 6A) for injecting a gas is disposed.

  The laser irradiation unit 44 is provided with a laser oscillator (not shown) that pulse-oscillates a laser beam having a wavelength that shows absorbency to the workpiece 11. For example, when the workpiece 11 is a wafer made of a semiconductor material such as silicon, it is possible to use a laser oscillator or the like which pulse-oscillates a laser beam having a wavelength of 355 nm using a laser medium such as Nd: YAG.

  Further, the laser irradiation unit 44 is provided with a condenser for condensing a laser beam pulse-oscillated from a laser oscillator, and the laser beam is irradiated to the workpiece 11 held by the chuck table 40 and collected. Light up. For example, by moving the chuck table 40 in the X-axis direction while irradiating the laser beam by the laser irradiation unit 44, the workpiece 11 can be ablated along the X-axis direction to form a groove (kerf).

  The processed workpiece 11 is transported from the chuck table 40 to the cleaning unit 50 by the transport unit 14, for example. The cleaning unit 50 includes a holding table 52 for holding the workpiece 11 in the cylindrical cleaning space. A rotation drive source (not shown) for rotating the holding table 52 at a predetermined speed is connected to the lower part of the holding table 52.

  Above the holding table 52, a nozzle 54 for injecting a cleaning fluid (typically, two fluids in which water and air are mixed) toward the workpiece 11 is disposed. The workpiece 11 can be cleaned by rotating the holding table 52 holding the workpiece 11 and spraying the cleaning fluid from the nozzle 54. The workpiece 11 cleaned by the cleaning unit 50 is, for example, placed on the alignment unit 12 by the transport unit 14 and then stored in the cassette 10.

  Components such as the transport unit 14, the spin coater 16, the moving mechanism 22, the chuck table 44, the laser irradiation unit 44, the imaging unit 46, the nozzle 48, and the cleaning unit 50 are connected to the control unit 56. The control unit 56 controls the above-described components in accordance with a series of steps required for processing the workpiece 11. Further, a touch panel monitor (notification unit) 58 serving as a user interface is connected to the control unit 56.

  FIG. 3A is a side view partially in section for explaining the protective film forming step, and FIG. 3B is a sectional view for explaining the protective film forming step. As shown in FIGS. 3A and 3B, the protective film forming step is performed using the spin coater 16 of the laser processing apparatus 2 described above.

  Specifically, first, the workpiece 11 (frame 23) is carried out of the cassette 10 by the transport unit 14, and after the frame 23 is aligned by the positioning unit 12, the workpiece 11 is attached to the workpiece 11 The protective member 21 is brought into contact with the holding surface 18 a of the spinner table 18. By applying the negative pressure of the suction source in this state, the workpiece 11 is held on the spinner table 18 with the surface 11 a side exposed upward.

  Next, as shown in FIG. 3A, the liquid resin 31 is dropped toward the workpiece 11 from the nozzle 20 moved to the upper side of the workpiece 11. Further, the spinner table 4 is rotated to cover the surface 11 a of the workpiece 11 with the liquid resin 31. Thereby, the protective film 33 as shown in FIG. 3 (B) is completed. The surface of the protective film 33 is slightly dried before the workpiece 11 is processed by irradiation with a laser beam. When the spinner table 4 is rotated, the frame 23 is fixed by the clamp 18c.

  There is no particular limitation on the type of liquid resin 31 which is a raw material of the protective film 33. In this embodiment, for example, a liquid resin 31 which is substantially transparent in the visible range is used so that the key pattern can be easily detected in the subsequent alignment step or key pattern detection step. Further, in the present embodiment, the water-soluble liquid resin 31 is used so that the protective film 33 can be easily removed by the subsequent cleaning.

  The amount of the liquid resin 31 dropped to the workpiece 11 is adjusted within a range in which the protective film 33 having a thickness of 5 μm or less can be formed, for example. If the diameter of the workpiece 11 is 4 inches, 10 to 15 ml, typically about 12 ml of the liquid resin 31 may be dropped onto the workpiece 11. The rotation speed of the spinner table 4 may be, for example, 2000 rpm to 3000 rpm, and the rotation time of the spinner table may be, for example, 20 seconds to 40 seconds, typically about 30 seconds.

  After the protective film forming step, the device 15 is imaged by the imaging unit 46 through the protective film 33, and a key pattern is detected from the obtained image (captured image), and the position of the planned dividing line 13 from the position of this key pattern Perform an alignment step to determine FIG. 4 (A) is a partial cross-sectional side view for explaining the alignment step, and FIG. 4 (B) is an example of an image obtained in the alignment step.

  In the alignment step, first, the protection member 21 attached to the workpiece 11 is brought into contact with the holding surface 40 a of the chuck table 40. By applying the negative pressure of the suction source in this state, the workpiece 11 is held by the chuck table 40 with the surface 11 a side exposed upward. At the same time, the frame 23 is fixed by the clamp 42.

  Next, the chuck table 40 is moved and rotated to position, for example, a predetermined area of the chuck table 40 directly below the imaging unit 46. More specifically, the position of the chuck table 40 relative to the imaging unit 46 is adjusted such that the area including the key pattern of the device 15 is imaged by the imaging unit 46.

  Thereafter, as shown in FIG. 4A, the area including the key pattern of the device 15 is imaged by the imaging unit 46 through the protective film 33. Thereby, an image (captured image) as shown in FIG. 4 (B) is obtained. After this image is obtained, for example, the control unit 54 finds out the key pattern 15a in the image using a method such as pattern matching.

  The distance from the key pattern 15a to the dividing line 13 is predetermined and known to the control unit 54. Therefore, the control unit 54 can determine (determine) the position of the line to be divided 13 from the position of the found key pattern 15a. The position of the division planned line 13 determined is used in the next processing step or the like.

  After the alignment step, a processing step of irradiating the workpiece 11 with a laser beam having an absorbing wavelength to form a groove along the planned dividing line 13 is performed. FIG. 5 (A) is a partial cross-sectional side view for explaining the processing step, and FIG. 5 (B) and FIG. 5 (C) are cross-sectional views for explaining the processing step.

  In the processing step, first, the chuck table 40 is rotated to align the direction of the planned dividing line 13 to be processed with the X-axis direction. Further, the chuck table 40 is moved to align the position of the laser irradiation unit 44 on the extension of the planned dividing line 13 to be processed. The amount of rotation and the amount of movement of the chuck table 40 are determined based on, for example, the position of the planned dividing line 13 determined in the above-described alignment step.

  Thereafter, as shown in FIGS. 5A and 5B, while irradiating the laser beam 35 from the laser irradiation unit 44 toward the surface 11a of the workpiece 11, the chuck table 40 is in the X axis direction. Move it. Here, for example, the laser beam 35 is condensed in the vicinity of the surface 11 a of the workpiece 11. Further, the irradiation conditions (power, spot diameter, repetition frequency, etc.) of the laser beam 35 are adjusted in a range in which the workpiece 11 is not cut.

  As a result, it is possible to form a groove (kerf) 19a of a depth that does not cut the workpiece 11 by irradiating the laser beam 35 along the target dividing line 13. The above-described operation is repeated, for example, when the grooves 19a are formed along all the planned dividing lines 13, the machining step is finished.

  In this processing step, as shown in FIG. 5C, debris 19b adheres to the surface of the protective film 33 present in the vicinity of the groove 19a. As a result, the key pattern 15a in the device 15 can not be properly imaged from the surface 11a side of the workpiece 11, which affects the subsequent key pattern detection step.

  Therefore, in the method of processing a workpiece according to the present embodiment, gas is jetted to the surface 11a side of the workpiece 11 at an arbitrary timing during the processing step, and debris 19b attached to the protective film 33 is removed. Perform a debris removal step to remove. FIG. 6 (A) is a partial cross-sectional side view for describing the debris removal step, and FIG. 6 (B) is a cross-sectional view for describing the debris removal step.

  As shown in FIG. 6A, in the debris removing step, the gas 37 is injected to the surface 11a side of the workpiece 11 by the nozzle 48 to remove the debris 19b. There is no limitation on the type of gas, for example, compressed air can be used. In this case, if the pressure of compressed air is 0.2 MPa to 0.4 MPa and the diameter of the nozzle of the nozzle is about 3 mm to 8 mm, debris 19 b attached to the protective film 33 can be appropriately removed.

  There is no particular limitation on the aspect of the nozzle 48 and the like. For example, an air curtain or an air blow nozzle having a function of injecting a gas can be used as the nozzle 48. As shown in FIG. 6B, for example, when the debris 19b is removed to such an extent that the key pattern 15a can be detected in the next key pattern detection step, the debris removal step ends.

  After the debris removal step, an area including the key pattern 15a is imaged through the protective film 33, and the key pattern detection step of detecting the key pattern 15a from the obtained image (captured image) is performed. FIG. 7A is a partial cross-sectional side view for explaining the key pattern detection step, and FIG. 7B is an example of an image obtained in the key pattern detection step.

  In the key pattern detection step, first, the chuck table 40 is moved and rotated to position, for example, a predetermined area of the chuck table 40 immediately below the imaging unit 46. More specifically, the position of the chuck table 40 relative to the imaging unit 46 is adjusted such that the area including the key pattern 15 a of the device 15 is imaged by the imaging unit 46.

  Thereafter, as shown in FIG. 7A, the area including the key pattern 15a of the device 15 is imaged by the imaging unit 46 through the protective film 33. Thus, an image (captured image) as shown in FIG. 7B is obtained. After this image is obtained, for example, the control unit 54 finds out the key pattern 15a in the image using a method such as pattern matching. The key pattern 15a found out is used in the next judgment informing step.

  In the present embodiment, since the debris 19b attached to the protective film 33 in the debris removal step performed before the key pattern detection step is removed, the key pattern 15a can be detected by obtaining an appropriate image.

  After the key pattern detection step, it is determined whether the distance between the detected key pattern 15a and the groove 19a is within a preset range, and if it is not within the range (if it is out of the range), the operator is notified Perform the notification step of notifying to In the determination informing step, first, the control unit 54 obtains the distance between the key pattern 15a and the groove 19a.

  It is considered that there is no deviation between the position of the groove 19a recognized by the control unit 54 and the actual position of the groove 19a immediately after the groove 19a is formed. Therefore, the control unit 54 obtains the distance from the key pattern 15a detected in the key pattern detection step and the groove 19a recognized by the control unit 54.

  In the key pattern detection step, an area including the key pattern 15a and the groove 19a may be imaged, and the position of the groove 19a may be detected from the obtained image. In this case, the control unit 54 obtains the distance from the key pattern 15a detected in the key pattern detection step and the groove 19a.

  After determining the distance between the key pattern 15a and the groove 19a, the control unit 54 compares this distance with a preset range. The range serving as the reference of comparison is set based on, for example, the allowable deviation of the groove 19a. If the distance between the key pattern 15 a and the groove 19 a is within a preset range, the control unit 54 instructs each component to continue the processing of the workpiece 11.

  On the other hand, when the distance between the key pattern 15a and the groove 19a is not within the preset range (outside the range), the control unit 54 notifies the operator of that. Although the method of notification is not particularly limited, for example, display on the monitor 58, generation of warning sound, lighting (flashing) of a warning light, and the like can be employed. The operator who has received the notification can prevent the processing accuracy from being lowered, for example, by adjusting each component of the laser processing apparatus 2.

  As described above, in the method of processing a workpiece according to the present embodiment, the laser beam 35 having a wavelength having absorption to the workpiece 11 is irradiated to form the groove (kerf) 19 a along the planned dividing line 13. After the formation, the gas 37 is jetted to the surface 11 side of the workpiece 11 to remove the debris 19b attached to the protective film 33. Thereafter, the protective film 33 from which the debris 19b is removed is included in the region including the key pattern 15a. The key pattern 15a can be appropriately detected from an image (captured image) obtained by imaging by the imaging unit 46.

  That is, according to the method of processing a workpiece according to the present embodiment, the key pattern 15a of the device 15 can be appropriately detected even after the workpiece 11 is processed by irradiation with the laser beam 35. Therefore, when the distance between the detected key pattern 15a and the groove 19a is not within the preset range, the fact of that is notified to the operator can prevent the processing accuracy from being lowered.

  The present invention is not limited to the above-described embodiment and the like, and can be implemented with various modifications. For example, although the groove (kerf) 19a of the depth which does not cut the to-be-processed object 11 is formed in the process step of the said embodiment, the kerf which cuts the to-be-processed object 11 can also be formed.

  In the above embodiment, the debris 19b is removed from the protective film 33 by scattering the debris 19b around by the gas 37 injected from the nozzle 48, but the debris 19b is collected without being scattered around. May be FIG. 8 is a partial cross-sectional side view for explaining the debris removal step according to the modification. As shown in FIG. 8, by arranging the dust collection duct 60 on the downstream side of the flow of the gas 37 injected from the nozzle 48, the debris 19b removed from the protective film 33 is captured without being scattered around. It can gather.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

11 workpiece 11a front surface 11b back surface 13 division planned line (street)
15 device 15a key pattern 17 functional layer 19a groove (calf)
19 b debris 21 protective member 23 frame 31 liquid resin 33 protective film 35 laser beam 37 gas 2 laser processing apparatus 4 base 4 a projecting portion 6 support structure 6 a support arm 8 cassette elevator 10 cassette 12 alignment unit 14 transport unit 16 spin coater 18 Spinner table 18a holding surface 18b suction path 18c clamp 20 nozzle 22 moving mechanism (machining feed mechanism, indexing feed mechanism)
24 Y-axis guide rail 26 Y-axis moving table 28 Y-axis ball screw 30 Y-axis pulse motor 32 X-axis guide rail 34 X-axis moving table 36 X-axis ball screw 38 table base 40 chuck table 40a holding surface 40b suction path 42 clamp 44 laser irradiation Unit 46 Imaging unit (camera)
48 nozzle 50 cleaning unit 52 holding table 54 injection nozzle 56 control unit 58 monitor (notification unit)
60 ducts

Claims (3)

A processing method of a workpiece, in which a workpiece on which a device is formed is processed in each area on the surface side divided by a crossing planned dividing line,
A protective member sticking step of sticking a protective member on the back surface of the workpiece;
Forming a protective film by coating a liquid resin on the surface of the workpiece to which the protective member is attached;
An area including a key pattern which is a characteristic pattern of the device is imaged over the protective film, and the key pattern is detected from a captured image obtained, and the planned division line at a predetermined distance from the key pattern An alignment step to determine the position;
A processing step of irradiating a laser beam of a wavelength having absorption with respect to the work piece at the position of the planned dividing line determined in the alignment step to form a kerf along the planned dividing line;
A debris removal step of injecting a gas onto the surface side of the workpiece and removing debris attached to the protective film in the processing step;
A key pattern detection step of imaging an area including the key pattern through the protective film from which the debris is removed, and detecting the key pattern from a captured image obtained;
And a judgment informing step of judging whether the distance between the detected key pattern and the kerf is within a preset range and informing the operator if the distance is out of the range. Processing method.   The method according to claim 1, wherein the protective film is formed by spin-coating the liquid resin on the surface of the workpiece.   3. The key pattern detection step according to claim 1 or 2, wherein the area including the key pattern and the kerf is imaged, and the position of the kerf is further detected from the captured image obtained. Processing method of workpieces.