Method for confirming processing performance of laser processing equipment

Abstract

The present invention provides a method for confirming the processing performance of a laser processing device, which shortens the processing time and reduces the use area or consumption of a workpiece used for test processing. The method is a method for confirming the processing performance of a laser processing device that processes a workpiece using a laser beam having a wavelength absorbed by the workpiece, and comprises the following steps: a holding step, in which the workpiece is held using a chuck table of the laser processing device; a processing mark forming step, in which the height of the focal point of the laser beam is changed while the workpiece and the focal point are relatively moved in a predetermined direction perpendicular to the thickness direction of the workpiece, thereby forming a processing mark on the upper surface of the workpiece; a photographing step, in which a plurality of regions of the processing mark formed by the processing mark forming step are photographed; and a confirmation step, in which the processing performance of the laser processing device is confirmed based on the image obtained by the photographing step.

Description

Technical Field

[0001] The present invention relates to a method for confirming the processing performance of a laser processing device, wherein a workpiece is processed using a laser beam having a wavelength absorbed by the workpiece. Background Art

[0002] The device chips assembled in various electronic devices are obtained as follows: the front side of the chip is divided into multiple areas by multiple predetermined dividing lines arranged in a grid shape, devices such as integrated circuits are formed in each area, and then the chip is divided along each predetermined dividing line to obtain the above-mentioned device chips.

[0003] When dividing a plate-shaped workpiece such as a wafer, for example, a laser processing device is used that includes a laser beam irradiation unit capable of irradiating a laser beam having a wavelength absorbed by the workpiece (see, for example, Patent Document 1).

[0004] The laser beam irradiation unit generally includes a laser oscillator and an optical system composed of a plurality of optical components such as a reflector and a lens. The laser beam generated by the laser oscillator is introduced to the workpiece via the optical system.

[0005] The optical system includes a condenser lens for converging the laser beam. When the laser beam has a wavelength absorbed by the workpiece, when the laser beam condensed by the condenser lens is irradiated onto the workpiece, a groove or the like is formed in the workpiece by ablation processing.

[0006] However, when the position and angle of the optical component are deviated due to vibration, heat, etc., the processing performance of the laser processing device may change. When the processing performance changes, the workpiece cannot be processed appropriately.

[0007] Therefore, sometimes, a work is performed in which the height position of the condensing lens is positioned at a height different from a preset height, ablation processing is experimentally performed on the workpiece, and the height position of the condensing point is confirmed (see, for example, Patent Document 2).

[0008] However, the method described in Patent Document 2 requires positioning the condenser lens at a plurality of different heights, and performing ablation processing on the workpiece to form a plurality of linear processing grooves while the condenser lens is fixed at each height.

[0009] Therefore, there are the following problems: as the number of processing grooves increases, the time required for processing the workpiece increases. In addition, when the number of processing grooves increases, sometimes one workpiece is not enough and multiple workpieces are required. Therefore, there is also the problem of increasing the use area or consumption of the workpiece.

[0010] Patent Document 1: Japanese Patent Application Publication No. 2007-275912

[0011] Patent Document 2: Japanese Patent Application Publication No. 2013-78785 Summary of the invention

[0012] The present invention is completed in view of this problem, and its purpose is to provide a method for confirming the processing performance of a laser processing device, which can shorten the processing time and reduce the usage area or consumption of the workpiece used for test processing when confirming the processing performance of the laser processing device.

[0013] According to one embodiment of the present invention, a method for confirming the processing performance of a laser processing device is provided, wherein the laser processing device processes a workpiece using a laser beam having a wavelength absorbed by the workpiece, wherein the method for confirming the processing performance of the laser processing device has the following steps: a holding step, in which the workpiece is held using a chuck table of the laser processing device; a processing mark forming step, in which the workpiece and the focusing point are relatively moved in a specified direction perpendicular to the thickness direction of the workpiece while changing the height of the focal point of the laser beam, thereby forming a processing mark on the upper surface of the workpiece; a photographing step, in which a plurality of areas of the processing mark formed by the processing mark forming step are photographed; and a confirmation step, in which the processing performance of the laser processing device is confirmed based on the image obtained by the photographing step.

[0014] Preferably, in the photographing step, the first area including the narrowest portion of the processing mark in a direction perpendicular to the thickness direction and the prescribed direction is photographed, and the confirmation step includes the following height position determination step: determining the height at which the focusing lens of the laser processing device is positioned when the processing mark with the narrowest width is formed based on the image of the first area.

[0015] In addition, the confirmation step preferably includes the following steps: an offset detection step, detecting the offset between the baseline and the center line in at least two different areas, the baseline is set in the shooting area of ​​the shooting unit of the laser processing device, and the center line is located at the center of the width of the processing mark in the direction perpendicular to the specified direction and parallel to the specified direction; and a step of judging whether adjustment is required, after the offset detection step, if each of the offsets in the at least two areas is within an allowable range, it is judged that there is no need to adjust the optical system used to irradiate the laser beam to the workpiece, and if each of the offsets in the at least two areas is outside the allowable range, it is judged that the optical system needs to be adjusted.

[0016] In addition, the confirmation step preferably includes the following steps: a detection step of detecting a dark area whose brightness is below a specified value in the overall image of the processing mark formed based on the images of the multiple areas captured by the shooting step; a calculation step of calculating the range of the height of the focusing lens of the laser processing device corresponding to the dark area; and a recording step of recording the result of the calculation step. The method for confirming the processing performance of the laser processing device also has the following time-dependent change confirmation step: performing a series of steps including the processing mark forming step, the shooting step, the detection step, the calculation step and the recording step multiple times, and comparing the results recorded in each recording step of the series of steps, thereby confirming the time-dependent change of the processing performance of the laser processing device.

[0017] In a method for confirming the processing performance of a laser processing device according to one embodiment of the present invention, a processing mark is formed on the upper surface of the workpiece by relatively moving the workpiece and the focusing point in a predetermined direction perpendicular to the thickness direction of the workpiece while changing the height of the focusing point of the laser beam (processing mark forming step). In addition, a plurality of regions of the processing mark formed in the processing mark forming step are photographed (photographing step), and the processing performance of the laser processing device is confirmed based on the image obtained in the photographing step (confirming step).

[0018] In this way, a linear processing mark is formed on the upper surface of the workpiece while changing the height of the focal point of the laser beam, so that the processing results when the focal point is positioned at multiple heights can be obtained. Therefore, compared with the case where multiple linear processing marks are formed, the processing time can be shortened. In addition, the desired processing result can be obtained by forming at least one linear processing mark, so the use area or consumption of the workpiece for test processing can be reduced compared with the case where multiple linear processing marks are formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a perspective view of a laser processing device.

[0020] Figure 2 It is a partial cross-sectional side view of a workpiece and the like schematically showing a processing mark forming step.

[0021] Figure 3 It is a plan view of a workpiece schematically showing an overall image of a processing mark.

[0022] Figure 4 This is a flowchart of the method for confirming the processing performance of the laser processing apparatus according to the first embodiment.

[0023] Figure 5 (A) is a schematic diagram of an image of the second region of a processing mark. Figure 5 (B) is a schematic diagram of an image of the first region of a processing mark. Figure 5 (C) is a schematic diagram of an image of the third region of a processing mark.

[0024] Figure 6 (A) is a schematic diagram of an image of the second region of another processing mark. Figure 6 (B) is a schematic diagram of an image of the first region of another processing mark. Figure 6 (C) is a schematic diagram of an image of the third region of another processing mark.

[0025] Figure 7 This is a flowchart of a method for confirming the processing performance of the laser processing apparatus according to the second embodiment.

[0026] Figure 8 (A) is a schematic diagram of the light and dark image of the first processing mark. Figure 8 (B) is a schematic diagram of the light and dark image of the second processing mark. Figure 8 (C) is a schematic diagram of the light and dark image of the third processing mark. Figure 8 (D) is a schematic diagram of the light and dark image of the fourth processing mark.

[0027] Fig. 9 This is a flowchart of a method for confirming the processing performance of the laser processing apparatus according to the third embodiment.

[0028] Fig.10 : is a graph showing the width of the dark area corresponding to the height of the condenser lens.

[0029] Description of symbols

[0030] 11: workpiece; 11a: upper surface; 11b: lower surface; 13: adhesive tape (scribing tape); 15: frame; 17: frame unit; 21: laser beam; 23: focal point; 25: processing mark; 25a: first area; 25b: second area; 25c: third area; 25d: dark area; 25e: bright area; 25-1: first processing mark; 25-2: second processing mark; 25-3: third processing mark; 25-4: fourth processing mark; 27: center line; 2: laser processing device; 4: base; 6: horizontal moving mechanism (processing feed mechanism, indexing feed mechanism); 8: Y-axis guide rail; 10: Y-axis moving table; 12: Y-axis ball screw; 14: Y-axis pulse motor; 16: X-axis guide rail ; 18: X-axis movable worktable; 20: X-axis ball screw; 22: X-axis pulse motor; 24: worktable base; 26: chuck worktable; 26a: holding surface; 28: fixture; 30: supporting structure; 32: height adjustment mechanism; 34: Z-axis guide rail; 36: Z-axis movable worktable; 38: Z-axis pulse motor; 40: support; 42: laser beam irradiation unit; 44: housing; 46: condenser; 46a: condenser lens; 48: shooting unit; 50: display screen; 50a: 1st reference line; 50b: 2nd reference line; 52: control unit; A, A1, A2, A3: height; B, B1, B2: offset; L, L1, L2, L3, L4: length; W: width; X1: arrow. DETAILED DESCRIPTION

[0031] An embodiment of one aspect of the present invention will be described with reference to the drawings. Figure 1 2 is a perspective view of the laser processing device 2. Figure 1 , a part of the components of the laser processing device 2 is shown by functional blocks. In addition, the X-axis direction (processing feed direction), the Y-axis direction (indexing feed direction), and the Z-axis direction (height direction) used in the following description are perpendicular to each other.

[0032] like Figure 1 As shown, the laser processing device 2 has a base 4 for supporting various components. A horizontal moving mechanism (processing feed mechanism, indexing feed mechanism) 6 is provided on the upper surface of the base 4. The horizontal moving mechanism 6 has a pair of Y-axis guide rails 8 fixed to the upper surface of the base 4 and substantially parallel to the Y-axis direction.

[0033] The Y-axis movable table 10 is slidably mounted on the Y-axis guide rail 8. A nut portion (not shown) is provided on the lower surface side of the Y-axis movable table 10. A Y-axis ball screw 12 substantially parallel to the Y-axis guide rail 8 is rotatably coupled to the nut portion of the Y-axis movable table 10.

[0034] A Y-axis pulse motor 14 is connected to one end of the Y-axis ball screw 12. When the Y-axis pulse motor 14 rotates the Y-axis ball screw 12, the Y-axis moving table 10 moves in the Y-axis direction along the Y-axis guide rail 8.

[0035] A pair of X-axis rails 16 substantially parallel to the X-axis direction are provided on the upper surface of the Y-axis moving table 10. The X-axis moving table 18 is slidably mounted on the X-axis rails 16. A nut portion (not shown) is provided on the lower surface side of the X-axis moving table 18.

[0036] An X-axis ball screw 20 substantially parallel to the X-axis guide rail 16 is rotatably coupled to the nut portion of the X-axis moving table 18. An X-axis pulse motor 22 is connected to one end of the X-axis ball screw 20. When the X-axis ball screw 20 is rotated by the X-axis pulse motor 22, the X-axis moving table 18 moves in the X-axis direction along the X-axis guide rail 16.

[0037] A cylindrical table base 24 is provided on the upper surface side of the X-axis moving table 18. A chuck table 26 is provided on the upper portion of the table base 24. A rotation drive source (not shown) such as a motor is connected to the lower portion of the table base 24.

[0038] The force generated by the rotation drive source rotates the chuck table 26 about a rotation axis substantially parallel to the Z-axis direction. The table base 24 and the chuck table 26 are moved in the X-axis direction and the Y-axis direction by the horizontal moving mechanism 6 described above.

[0039] Four clamps 28 for fixing the frame 15 are respectively provided on the outer peripheral portion of the chuck table 26. In addition, a disk-shaped porous plate formed of a porous material is provided on a part of the upper surface side of the chuck table 26, for example.

[0040] The porous plate is connected to a suction source (not shown) such as an ejector via a suction path (not shown) provided inside the chuck table 26. When the suction source is operated, negative pressure is generated on the substantially flat upper surface of the porous plate, so that the upper surface functions as a holding surface 26a for sucking and holding the workpiece 11 etc. placed on the upper surface.

[0041] The workpiece 11 has a plate shape including an upper surface 11a and a lower surface 11b that are substantially flat and parallel to each other. The workpiece 11 in this embodiment is a wafer made of silicon, but the workpiece 11 may be made of semiconductors other than silicon, ceramics, resins, metals, glass, and the like.

[0042] When the workpiece 11 is processed by the laser processing device 2 , an adhesive tape (dicing tape) 13 having a larger diameter than the workpiece 11 is attached to the lower surface 11 b of the workpiece 11 .

[0043] Moreover, the ring-shaped frame 15 formed of metal is adhered to the outer peripheral part of the adhesive tape 13. Thus, the frame unit 17 in which the workpiece 11 is supported by the frame 15 via the adhesive tape 13 is formed.

[0044] A columnar support structure 30 having a first side surface substantially perpendicular to the X and Y axis directions is provided on one side of the horizontal moving mechanism 6 in the Y axis direction. A height adjustment mechanism 32 is disposed on the first side surface of the support structure 30 .

[0045] The height adjustment mechanism 32 includes a pair of Z-axis guide rails 34 fixed to the first side surface and substantially parallel to the Z-axis direction. The Z-axis moving table 36 is slidably mounted on the Z-axis guide rails 34 .

[0046] A nut portion (not shown) is provided on the back side (Z-axis guide rail 34 side) of the Z-axis moving table 36. A Z-axis ball screw (not shown) substantially parallel to the Z-axis guide rail 34 is rotatably coupled to the nut portion of the Z-axis moving table 36.

[0047] A Z-axis pulse motor 38 is connected to one end of the Z-axis ball screw. When the Z-axis pulse motor 38 rotates the Z-axis ball screw, the Z-axis moving table 36 moves in the Z-axis direction along the Z-axis guide rail 34 .

[0048] A bracket 40 is fixed to the front side of the Z-axis moving table 36, and a part of a laser beam irradiation unit 42 is fixed to the bracket 40. The laser beam irradiation unit 42 has a laser oscillator (not shown) fixed to the base 4, for example.

[0049] The laser oscillator includes a laser medium such as Nd:YAG suitable for laser oscillation, and generates a pulsed laser beam (for example, average output of 1.0 W and repetition frequency of 10 kHz) of a wavelength (for example, 355 nm) absorbed by the workpiece 11 .

[0050] The generated laser beam is emitted to the cylindrical housing 44 side fixed to the holder 40. The housing 44 accommodates a part of the optical system constituting the laser beam irradiation unit 42.

[0051] This optical system is mainly composed of optical components such as a reflective mirror and a lens. The housing 44 guides the laser beam emitted from the laser oscillator to the condenser 46 provided at the end of the housing 44 in the Y-axis direction.

[0052] Another part of the optical system constituting the laser beam irradiation unit 42 is provided in the condenser 46. The laser beam is introduced from the housing 44 to the condenser 46, and its path is changed downward by a reflection mirror (not shown) provided in the condenser 46.

[0053] Then, the light is incident on the condenser lens 46a (see Figure 2 ). Then, the laser beam is irradiated from the condenser 46 to the workpiece 11 in a manner of being condensed outside the condenser lens 46a.

[0054] An imaging unit 48 fixed to the housing 44 of the laser beam irradiation unit 42 is provided in a region on one side of the condenser 46 in the X-axis direction. The imaging unit 48 includes, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor, etc. The imaging unit 48 is used when imaging the upper surface 11a side of the workpiece 11 held by the chuck table 26.

[0055] The upper part of the base 4 is covered by a cover (not shown) capable of accommodating various components. A touch panel display 50 as a user interface is provided on the side surface of the cover.

[0056] Various conditions applied when processing the workpiece 11 are input to the laser processing device 2 via, for example, the display screen 50. In addition, the image generated by the imaging unit 48 is displayed on the display screen 50. In this way, the display screen 50 functions as an input / output device.

[0057] The horizontal movement mechanism 6, height adjustment mechanism 32, laser beam irradiation unit 42, imaging unit 48, display screen 50 and other components are connected to the control unit 52. The control unit 52 controls the above components according to a series of steps required for processing the workpiece 11.

[0058] The control unit 52 is composed of a computer including a processing device such as a CPU (Central Processing Unit) and a storage device such as a flash memory. The processing device is operated according to software such as a program stored in the storage device, so that the control unit 52 functions as a specific unit in which software and the processing device (hardware resources) cooperate.

[0059] The control unit 52 includes an image processing unit (not shown) that performs edge detection processing on the image captured by the imaging unit 48. In addition to edge detection, the image processing unit also processes an image by joining multiple images. In addition, the image processing unit also measures the width and length of the measurement object and calculates the coordinates of the edge of the measurement object.

[0060] The control unit 52 further includes a calculation unit (not shown) for performing a predetermined calculation. The calculation unit calculates the time t (i.e., the time elapsed from the start of processing), the moving speed V of the chuck table 26 in the X-axis direction, and the moving speed V of the chuck table 26 in the X-axis direction. X , the moving speed V of the condenser lens 46a in the Z-axis direction Z , the initial position of the condensing lens 46a, etc., and the coordinates of the focusing point 23, the height of the condensing lens 46a, etc. are calculated.

[0061] Next, use Figure 2 , Figure 3 as well as Figure 4 A method of confirming the processing performance of the laser processing apparatus 2 by processing the workpiece 11 using the laser processing apparatus 2 will be described. Figure 4 This is a flowchart of the method for confirming the processing performance of the laser processing device 2 according to the first embodiment.

[0062] When the workpiece 11 is processed using the laser processing device 2, the frame unit 17 is first placed on the chuck table 26 in such a way that the upper surface 11a of the workpiece 11 is exposed. Then, the suction source is operated to hold the lower surface 11b side of the workpiece 11 with the holding surface 26a through the adhesive tape 13 (holding step (S10)). In addition, at this time, the four sides of the frame 15 are fixed by four clamps 28.

[0063] After the holding step ( S10 ), the upper surface 11 a side of the workpiece 11 is subjected to ablation processing to form processing marks 25 consisting of grooves, cracks, etc. on the upper surface 11 a (processing mark forming step ( S20 )). Figure 2 It is a partial cross-sectional side view of the workpiece 11 and the like schematically showing the processing mark forming step ( S20 ). Figure 3 It is a plan view of the workpiece 11 schematically showing the entire image of the processing mark 25 .

[0064] In the processing mark forming step ( S20 ), while irradiating the laser beam 21 , the condenser 46 is moved in the Z-axis direction by the height adjustment mechanism 32 , and the workpiece 11 and the condenser 46 are relatively moved in the X-axis direction by the horizontal movement mechanism 6 .

[0065] Thus, in the processing mark forming step (S20) of the present embodiment, the following dual axis moving processing is performed while the laser beam 21 is irradiated: the Z axis ball screw of the height adjustment mechanism 32 is moved while the X axis ball screw 20 of the horizontal movement mechanism 6 is moved.

[0066] When the chuck table 26 is moved in the X-axis direction (direction of arrow X1) perpendicular to the thickness direction (i.e., Z-axis direction) of the workpiece 11 held by the holding surface 26a via the adhesive tape 13, the workpiece 11 and the focusing lens 46a move relative to each other in the X-axis direction.

[0067] The relative moving distance between the chuck table 26 and the focusing lens 46a is, for example, 50 mm. When the workpiece 11 and the focusing lens 46a are relatively moved in the X-axis direction while being irradiated with the laser beam 21, the workpiece 11 is processed by the focusing point 23 moving in the X-axis direction.

[0068] The condenser lens 46a is fixed in the condenser 46, and the movement of the condenser 46 can be regarded as equivalent to the movement of the condenser lens 46a. When the condenser lens 46a moves, the height of the focal point 23 of the laser beam 21 that is focused to a predetermined height by the condenser lens 46a also moves together. For example, when the condenser lens 46a rises, the focal point 23 also rises. The moving distance of the condenser lens 46a is, for example, 0.6 mm.

[0069] In the processing mark forming step ( S20 ), first, the condenser lens 46 a is positioned at a height A1 . The height A1 is set so that the distance between the condenser lens 46 a and the upper surface 11 a is smaller than the focal length of the condenser lens 46 a .

[0070] When the focusing lens 46a is at the height A1, the focal point 23 of the laser beam 21 is located below the upper surface 11a and inside the workpiece 11. In this case, the laser beam 21 is in a so-called negative defocus (hereinafter referred to as negative DF) state. In addition, the X coordinate of the focal point 23 at this time is, for example, x1.

[0071] Next, when the chuck table 26 is moved in the direction of arrow X1 while the condenser lens 46a is raised, the condenser lens 46a reaches the height A2. At this time, the distance between the condenser lens 46a and the upper surface 11a is equal to the focal length of the condenser lens 46a, for example.

[0072] When the distance between the height A2 and the upper surface 11a is equal to the focal length of the condenser lens 46a, the focal point 23 of the laser beam 21 is in a so-called just-focused (hereinafter referred to as JF) state located on the upper surface 11a. In addition, at this time, the X coordinate of the focal point 23 is x2 located in the opposite direction of the arrow X1 relative to x1.

[0073] When the chuck table 26 is further moved in the direction of arrow X1 while the condenser lens 46a is further raised, the condenser lens 46a reaches a height A3. The height A3 is set so that the distance between the condenser lens 46a and the upper surface 11a is larger than the focal length of the condenser lens 46a.

[0074] When the focusing lens 46a is at the height A3, the focal point 23 of the laser beam 21 is located above the upper surface 11a. In this case, the laser beam 21 is in a so-called positive defocus (hereinafter referred to as positive DF) state. In addition, at this time, the X coordinate of the focal point 23 is x3, which is located in the opposite direction of the arrow X1 with respect to x2.

[0075] When the focusing lens 46a is located at a height A2, as shown in FIG. Figure 3 As shown in the first region 25a of FIG. 1 , the width (length in the Y-axis direction) of the processing mark 25 at the position x2 is the narrowest compared with the widths at other positions in the X-axis direction of the processing mark 25.

[0076] On the other hand, when the condenser lens 46 a is located at the height A1 or the height A3 , a wider area of ​​the upper surface 11 a is irradiated with the laser beam 21 than when the condenser lens 46 a is located at the height A2 .

[0077] Therefore, the width of the processing mark 25 at x1 and x3 is wider than the width of the processing mark 25 at x2. Figure 3 As shown, the second region 25b (region including x1) and the third region 25c (region including x3) are regions having a width wider than the first region 25a.

[0078] In this way, by forming one linear processing mark 25 on the upper surface 11 a while continuously changing the height of the focal point 23 of the laser beam 21 , a processing result including information equivalent to that when the focal point 23 is positioned at a plurality of heights can be obtained.

[0079] Therefore, compared with the case where a plurality of linear processing grooves are formed on the workpiece by positioning the focusing lens at different heights, the processing time can be shortened. In addition, the desired processing result can be obtained by forming at least one linear processing mark 25, so the use area or consumption of the workpiece 11 used for test processing can be reduced compared with the case where a plurality of linear processing grooves are formed.

[0080] After the processing mark forming step (S20), the plurality of regions including the first region 25a, the second region 25b, and the third region 25c are photographed by the photographing unit 48 (photographing step (S30)). Next, based on the image obtained in the photographing step (S30), the processing performance of the laser processing device 2 is confirmed (confirmation step (S40)).

[0081] In the confirmation step ( S40 ) of the first embodiment, the height of the condenser lens 46 a (ie, the condenser 46 ) when forming the processing mark 25 with the narrowest width is determined based on the image of the first region 25 a (height position determination step).

[0082] More specifically, first, the image processing unit of the control unit 52 determines the X coordinate of the focal point 23 when the processing mark 25 is narrowest in the image of the first region 25 a (ie, the above-mentioned x2).

[0083] Next, the calculation unit of the control unit 52 calculates the time t when the focal point 23 is at x2 (that is, the time elapsed from the start of processing). Z , the initial position of the condensing lens 46a, etc., and calculate the height (Z coordinate) of the condensing lens 46a when the focal point 23 is at x2.

[0084] Thus, in this embodiment, the height of the focusing lens 46a when the focusing point 23 is at x2 can be determined by forming a linear processing mark 25. Therefore, compared with the case where a plurality of processing grooves are formed to confirm the height of the focusing point, the processing time can be shortened, and the use area or consumption of the workpiece 11 can be further reduced.

[0085] In addition, when the laser processing device 2 is used continuously for a certain period of time or more, the height of the focal point 23 may change due to the thermal lens effect generated in the focusing lens 46a. If S10 to S40 described in this embodiment are performed multiple times, the change in the height of the focal point 23 (that is, the change in the processing performance of the laser processing device 2 over time) can also be confirmed.

[0086] Next, use Figure 5 (A) to Figure 5 (C) Figure 6 (A) to Figure 6 (C) and Figure 7 , a method for confirming the processing performance of the laser processing device 2 according to the second embodiment is described. Figure 7 This is a flowchart of a method for confirming the processing performance of the laser processing device 2 according to the second embodiment.

[0087] In the second embodiment, the holding step (S10), the processing mark forming step (S20) and the photographing step (S30) are performed in the same manner as in the first embodiment. However, in the confirmation step (S40) of the second embodiment, the following offset detection step (S42) is performed: the offset between the reference line and the center line is detected, and the center line is located at the center of the width of the processing mark 25 in the Y-axis direction and is parallel to the X-axis direction.

[0088] Figure 5 (A) to Figure 5 (C) is a schematic diagram of an image of a processing mark 25 used in the deviation amount detection step (S42). Figure 5 (A) to Figure 5 The image shown in the schematic diagram of (C) is obtained while the imaging unit 48 is positioned on one processing mark 25 and the processing object 11 is moved parallel to the X-axis direction using the horizontal moving mechanism 6 .

[0089] Figure 5 (A) is a schematic diagram of an image of the second region 25b of a processing mark 25. Figure 5 (B) is a schematic diagram of an image of a first region 25a of a processing mark 25. Figure 5 (C) is a schematic diagram of an image of the third region 25 c of a processing mark 25 .

[0090] In the deviation amount detection step ( S42 ), an image obtained by adding a first reference line 50 a parallel to the X-axis direction and a second reference line 50 b parallel to the Y-axis direction to the image captured in the capturing step ( S30 ) is used.

[0091] The first reference line 50a and the second reference line 50b are not formed on the actual processing mark 25 but are set in the imaging area when the processing mark 25 is imaged by the imaging unit 48. The first reference line 50a and the second reference line 50b constitute a cross line for indicating the center of the imaging area. Figure 5 (A) to Figure 5 The same as in (C).

[0092] exist Figure 5 (A) to Figure 5 In (C), the center line 27 of the Y-axis direction of the width of the processing mark 25 located in each area is also shown. Figure 5 (A) to Figure 5 In (C), the center line 27 overlaps with the first reference line 50a.

[0093] In the offset detection step (S42), for example, the image processing unit of the control unit 52 detects the Y-axis direction offset B between the first reference line 50a and the center line 27. However, the offset detection step (S42) is not limited to the control unit 52, and may be performed by an operator.

[0094] In the offset detection step (S42), for example, in the first region 25a ( Figure 5 In (B)), while the Y coordinates of the first reference line 50a and the center line 27 are made consistent, the offset B in the Y-axis direction between the first reference line 50a and the center line 27 in the second area 25b and the third area 25c is detected.

[0095] The allowable range of the offset B is preset. The allowable range of the offset B is, for example, greater than -5 μm and less than +5 μm, and more preferably greater than -3 μm and less than +3 μm. In addition, in the present embodiment, when the center line 27 is located on one side of the Y-axis direction relative to the first reference line 50a, the offset B is negative, and when the center line 27 is located on the other side of the Y-axis direction relative to the first reference line 50a, the offset B is positive.

[0096] In the confirmation step (S40) of the second embodiment, the following step (S43) of determining whether adjustment is required is performed: based on the offset B detected in the offset detection step (S42), it is determined whether adjustment of the optical system for irradiating the laser beam 21 to the workpiece 11 is required.

[0097] exist Figure 5 (A) to Figure 5 In the example of a processing mark 25 shown in (C), the offset B is substantially zero. Therefore, in the first area 25a, the second area 25b, and the third area 25c, the offset B is within the allowable range. In this case, the control unit 52 determines that there is no need to adjust the optical system ("Yes" in S43).

[0098] However, the position where the laser beam 21 is irradiated to the workpiece 11 may change due to the position, angle, etc. of optical components such as reflectors and lenses. For example, due to the position, angle, etc. of optical components, the laser beam 21 may be incident on the condenser lens 46a in a state tilted relative to the optical axis of the condenser lens 46a. In this case, the irradiation position of the laser beam 21 changes compared to the case where the laser beam 21 is incident on the condenser lens 46a parallel to the optical axis.

[0099] Figure 6 (A) to Figure 6 (C) is a schematic diagram of an image of another processing mark 25 formed through S10 and S20. Figure 6 (A) to Figure 6 The image shown in the schematic diagram of (C) is obtained by moving the workpiece 11 in parallel in the X-axis direction using the horizontal moving mechanism 6 while the imaging unit 48 is positioned on another processing mark 25 .

[0100] Figure 6 (A) is a schematic diagram of an image of the second region 25b of another processing mark 25, Figure 6 (B) is a schematic diagram of an image of the first region 25a of another processing mark 25, Figure 6 (C) is a schematic diagram of an image of the third region 25 c of another processing mark 25 .

[0101] In the step (S42) of detecting the amount of deviation of another processing mark 25, the image processing unit also detects the amount of deviation B in the Y-axis direction between the first reference line 50a and the center line 27. Figure 6 In (A), the center line 27 (indicated by the dotted line) is located 10 μm to one side of the first reference line 50a in the Y-axis direction. That is, the offset B1 (-10 μm) between the center line 27 and the first reference line 50a is outside the allowable range.

[0102] In addition, Figure 6 In (C), the center line 27 (indicated by the dotted line) is located on the other side of the Y-axis direction than the first reference line 50a, and the offset B2 (+10μm) between the center line 27 and the first reference line 50a is outside the allowable range. Figure 6 In (B), the center line 27 overlaps with the first reference line 50a, and the offset B between the center line 27 and the first reference line 50a is within the allowable range.

[0103] Thus, in the second area 25b ( Figure 6 (A)) and the third region 25c ( Figure 6 In (C)), the offset B between the center line 27 and the first reference line 50a in the Y-axis direction is outside the allowable range ("No" in S43). In this case, in the judgment step (S43) of whether adjustment is required, the control unit 52 determines that the optical system for irradiating the laser beam 21 to the workpiece 11 needs to be adjusted.

[0104] In the second embodiment, by forming one linear processing mark 25, it is possible to check the deviation of the optical system of the laser processing device 2. Therefore, it is possible to check whether the laser beam 21 is incident obliquely with respect to the optical axis of the condenser lens 46a.

[0105] After confirming the processing performance of the laser processing device 2, the operator adjusts the positions and angles of optical components such as reflectors and lenses (optical system adjustment step (S44)). After the optical system adjustment step (S44), S20 to S43 are performed again.

[0106] If the offset B in at least two different regions including the second region 25b and the third region 25c is within the allowable range, the method ends. However, if the offset B is outside the allowable range, S44 and S20 to S43 are repeated until the offset B disappears.

[0107] In addition, Figure 5 (B) and Figure 6 (B) shows an example in which the first reference line 50a is arranged to overlap with the center line 27. However, the first reference line 50a may be arranged at a position a predetermined distance C away from the center line 27 in the Y-axis direction.

[0108] In this case, in the offset detection step (S42), a value obtained by subtracting a predetermined distance C from the offset B between the first reference line 50a and the center line 27 (i.e., the magnitude of BC) is detected as the substantial offset. And, in the step (S43) of determining whether adjustment is necessary, it is determined whether the optical system needs to be adjusted based on whether the substantial offset is within the allowable range.

[0109] In addition, in the photographing step (S30) and the offset detection step (S42), if the area of ​​the processing mark 25 that is the object of photographing and detection includes two or more arbitrary areas of the processing mark 25, it is not limited to the second area 25b and the third area 25c, and can be any area.

[0110] Next, use Figure 8 (A) to Figure 8 (D) and Fig. 9 , a method for confirming the processing performance of the laser processing device 2 according to the third embodiment is described. Fig. 9 This is a flowchart of a method for confirming the processing performance of the laser processing device 2 according to the third embodiment.

[0111] In the third embodiment, the control unit 52 first determines whether a predetermined period (e.g., several hours, 1 day, 1 week, or 1 month) has passed since the processing performance of the laser processing device 2 was last confirmed (period determination step (S5)). Alternatively, the operator may determine whether a predetermined period has passed.

[0112] If the predetermined period has not passed (No in S5), the content is displayed on the display screen 50. In this case, the workpiece 11 is not processed. However, if the predetermined period has passed (Yes in S5), the content is displayed on the display screen 50.

[0113] If "yes" is determined in S5, for example, the operator sends a command to start processing to the control unit 52 via the display screen 50. Thus, processing of the workpiece 11 is started, and the holding step (S10), the processing mark forming step (S20), and the photographing step (S30) are sequentially performed in the same manner as in the first embodiment.

[0114] In the processing mark forming step (S20) of the third embodiment, one or more (for example, four) processing marks 25 are formed in different regions on the upper surface 11a side of the workpiece 11. And in the imaging step (S30), the chuck table 26 is moved in the X-axis direction in a state where the imaging unit 48 is positioned above one processing mark 25.

[0115] Thus, multiple regions of one processing mark 25 are photographed. In the photographing step (S30), for example, each region is photographed in a manner that the photographing regions partially overlap. And, the image processing unit of the control unit 52 joins the multiple regions to form an overall image of one processing mark 25. Similarly, an overall image of each processing mark 25 is obtained.

[0116] In the first region 25a and its vicinity, the upper surface 11a is processed with energy exceeding the processing threshold of the workpiece 11. The energy exceeding the processing threshold forms unevenness in the processed region. Therefore, due to diffuse reflection of light, the region is photographed as a dark region 25d (see FIG. 25d ) with a brightness below a predetermined value. Figure 8 (A) to Figure 8 (D)).

[0117] On the other hand, in the second region 25b and the third region 25c and their vicinities, the upper surface 11a side is processed with energy less than the processing threshold of the workpiece 11. The region processed with energy less than the processing threshold is a bright region 25e having a brightness greater than that of the first region 25a by a predetermined value (see Figure 8 (A) to Figure 8 In addition, Figure 8 (A) to Figure 8 In (D), a dotted line is marked on the outline of the bright region 25e.

[0118] In the imaging step ( S30 ) of the third embodiment, a bright-dark image including a relatively black dark region 25 d and a relatively white bright region 25 e is obtained. Figure 8(A) is a schematic diagram of a bright and dark image of the first processing mark 25-1 when the processing mark forming step (S20) is performed with the average output of the laser beam 21 being 1.0 W.

[0119] In the confirmation step ( S40 ) of the third embodiment, instead of S40 of the first embodiment, first, the image processing unit of the control unit 52 detects the dark region 25 d of at least one processing mark 25 (detection step ( S46 )).

[0120] After the detection step ( S46 ), the calculation unit of the control unit 52 calculates the range of the height A of the condenser lens 46 a corresponding to the length L in the X-axis direction of the dark region 25 d of at least one processing mark 25 (calculation step ( S47 )).

[0121] For example, the X coordinate (x 1A ) and the X coordinate (x 1B ) is calculated based on the height (upper end) of the condenser lens 46a corresponding to the height A of the condenser lens 46a. The calculated range of the height A of the condenser lens 46a is recorded in the storage device of the control unit 52 (recording step (S48)).

[0122] In this way, a series of steps including the maintaining step (S10), the processing mark forming step (S20), the photographing step (S30), the detecting step (S46), the calculating step (S47) and the recording step (S48) are performed at a predetermined period (e.g., every few hours, every day, every week or every month). Thus, the results of each recording step (S48) of the series of steps are recorded.

[0123] By comparing the results recorded in each recording step (S48) of a series of steps, it is possible to confirm the temporal change of the processing performance of the laser processing device 2 (temporal change confirmation step). For example, by observing the temporal change of the range of the height A of the condenser lens 46a corresponding to the length of the dark area 25d in the X-axis direction of the processing mark 25 with an average output of 1.0W recorded in a predetermined period, it is possible to determine whether an abnormality has occurred in the laser beam irradiation unit 42.

[0124] In the above-mentioned multiple recording step ( S48 ), the range of the height A corresponding to the first processing mark 25 - 1 is recorded, but a plurality of processing marks 25 may be formed and the time-dependent change confirmation step may be performed for each processing mark 25 .

[0125] Figure 8(B) is a schematic diagram of a light-dark image of the second processing mark 25-2 when the processing mark forming step (S20) is performed with an average power of 0.8W. Figure 8 (C) is a schematic diagram of a light-dark image of the third processing mark 25-3 when the processing mark forming step (S20) is performed with an average output of 0.6 W. Figure 8 (D) is a schematic diagram of a bright and dark image of the fourth processing mark 25-4 when the processing mark forming step (S20) is performed with an average output of 0.3W.

[0126] The lower the average output, the shorter the length L of the dark region 25 d in the X-axis direction. Figure 8 The first processing mark 25-1 shown in (A) has the longest length L1. Figure 8 The second processing mark 25-2 shown in (B) has a length L2 shorter than the length L1. Figure 8 The third processing mark 25-3 shown in (C) has a length L3 shorter than the length L2. Figure 8 The fourth processing mark 25-4 shown in (D) has a length L4 shorter than the length L3.

[0127] When the time-dependent change confirmation step is performed on each processing mark 25, the detection step (S46), the calculation step (S47), and the recording step (S48) are performed on the first processing mark 25-1 to the fourth processing mark 25-4.

[0128] In the calculation step (S47), the x-axis positions at both ends of the dark region 25d of the second processing mark 25-2 in the X-axis direction are calculated. 2A and x 2B The range of the height A of the corresponding condenser lens 46a is calculated. In addition, the x-axis portions located at both ends of the dark region 25d of the third processing mark 25-3 in the X-axis direction are calculated. 3A and x 3B The range of the height A of the corresponding condenser lens 46a is calculated.

[0129] In addition, the x-axis regions located at both ends of the dark region 25d of the fourth processing mark 25-4 in the X-axis direction are 4A and x 4B The range of the height A of the corresponding condenser lens 46a is calculated. In addition, in the recording step (S48), the calculated range of each height A is recorded. Thereby, the temporal change of the processing performance of the laser processing device 2 can be confirmed.

[0130] In the present embodiment, a plurality of processing marks 25 are formed by using laser beams 21 having different average outputs, so that the range of the dark region 25d can be determined according to the average outputs of the laser beams 21. Thus, the optimum processing conditions of the workpiece 11 (e.g., the value of the optimum average output exceeding the processing threshold of the workpiece 11) can also be determined.

[0131] In addition, in the above-mentioned detection step (S46), the length L of the dark area 25d in the X-axis direction is detected, but the width W of the dark area 25d in the Y-axis direction may also be detected. And in the calculation step (S47), the height A of the condenser lens 46a corresponding to the width W may be calculated.

[0132] Fig.10 : is a graph which shows the width W of the dark area 25d corresponding to the height A of the condenser lens 46a. Fig.10 The horizontal axis of takes the height A of the focal point 23 in the JF state as zero, represents the height A of the focal point 23 in the negative DF state as a negative number, and represents the height A of the focal point 23 in the positive DF state as a positive number. Fig.10 The vertical axis represents the width W of the dark region 25d.

[0133] The calculated range of the height A is recorded in the storage device of the control unit 52 (recording step (S48)). Then, a series of steps including the detection step (S46), the calculation step (S47) and the recording step (S48) are performed at a predetermined period (e.g., every few hours, every day, every week or every month). Thus, the results of each of the multiple recording steps (S48) of the series of steps are recorded.

[0134] By comparing the results recorded in each recording step (S48) of a series of steps, it is possible to confirm the time-dependent change in the processing performance of the laser processing device 2. Fig.10 As shown, in the multiple recording steps ( S48 ), the range of height A corresponding to all of the first processing mark 25 - 1 to the fourth processing mark 25 - 4 is recorded. However, the range of height A corresponding to at least one processing mark 25 may be recorded.

[0135] In addition, the structures and methods of the above-mentioned embodiments can be appropriately changed and implemented as long as they do not deviate from the scope of the purpose of the present invention. For example, the first embodiment, the second embodiment and the third embodiment can be combined with each other. In addition, in the above-mentioned embodiment, the workpiece 11 and the focusing lens 46a are relatively moved in the X-axis direction, but they can also be relatively moved in the Y-axis direction instead of the X-axis direction.

Claims

1. A method for confirming processing performance of a laser processing device, wherein the laser processing device processes a workpiece using a laser beam having a wavelength absorbed by the workpiece, characterized in that: The method for confirming the processing performance of the laser processing device has the following steps: A holding step, using a chuck table of the laser processing device to hold the workpiece; a processing mark forming step of relatively moving the workpiece and the focusing point in a predetermined direction perpendicular to the thickness direction of the workpiece while changing the height of the focusing point of the laser beam, thereby forming a processing mark on the upper surface of the workpiece, wherein the width of the processing mark continuously changes along the predetermined direction, and the processing mark has a narrow width region arranged in a manner sandwiched between two wide width regions in the predetermined direction; a photographing step of photographing a plurality of regions of the processing mark formed by the processing mark forming step; and a confirmation step of confirming the processing performance of the laser processing device based on the image obtained by the photographing step, In the photographing step, a first area including a portion where the width of the processing mark is narrowest in a direction perpendicular to the thickness direction and the predetermined direction is photographed, The confirmation step includes the following height position determination step: determining the height at which the focusing lens of the laser processing device is positioned when forming a processing mark with the narrowest width based on the image of the first area, In the height position determination step, the coordinates of the focal point in the specified direction when the processing mark is narrowest in the image of the first area are first determined, and then the time when the focal point is at the coordinates is calculated, and the height of the focusing lens when the focal point is at the coordinates is calculated based on the time, the moving speed of the focusing lens in the thickness direction of the workpiece, and the initial position of the focusing lens.

2. A method for confirming processing performance of a laser processing device, wherein the laser processing device processes a workpiece using a laser beam having a wavelength absorbed by the workpiece, characterized in that: The method for confirming the processing performance of the laser processing device has the following steps: A holding step, using a chuck table of the laser processing device to hold the workpiece; a processing mark forming step of relatively moving the workpiece and the focusing point in a predetermined direction perpendicular to the thickness direction of the workpiece while changing the height of the focusing point of the laser beam, thereby forming a processing mark on the upper surface of the workpiece, wherein the width of the processing mark continuously changes along the predetermined direction, and the processing mark has a narrow width region arranged in a manner sandwiched between two wide width regions in the predetermined direction; a photographing step of photographing a plurality of regions of the processing mark formed by the processing mark forming step; and a confirmation step of confirming the processing performance of the laser processing device based on the image obtained by the photographing step, The confirmation step includes the following steps: a step of detecting an offset amount, in which a reference line and a center line are aligned in one region of the processing mark, and in at least two other different regions of the processing mark, the reference line is set within a photographing region of a photographing unit of the laser processing device, and the center line is located at the center of a width of the processing mark in a direction perpendicular to the prescribed direction and is parallel to the prescribed direction; and A step for determining whether adjustment is required. After the offset detection step, if each of the offsets in the at least two areas is within an allowable range, it is determined that there is no need to adjust the optical system used to irradiate the laser beam to the workpiece; if each of the offsets in the at least two areas is outside the allowable range, it is determined that the optical system needs to be adjusted.

3. A method for confirming the processing performance of a laser processing device, wherein the laser processing device processes a workpiece using a laser beam having a wavelength absorbed by the workpiece, characterized in that: The method for confirming the processing performance of the laser processing device has the following steps: A holding step, using a chuck table of the laser processing device to hold the workpiece; a processing mark forming step of relatively moving the workpiece and the focusing point in a predetermined direction perpendicular to the thickness direction of the workpiece while changing the height of the focusing point of the laser beam, thereby forming a processing mark on the upper surface of the workpiece, wherein the width of the processing mark continuously changes along the predetermined direction, and the processing mark has a narrow width region arranged in a manner sandwiched between two wide width regions in the predetermined direction; a photographing step of photographing a plurality of regions of the processing mark formed by the processing mark forming step; and a confirmation step of confirming the processing performance of the laser processing device based on the image obtained by the photographing step, The confirmation step includes the following steps: a detection step of detecting a dark area having a brightness below a predetermined value in an overall image of the processing mark formed based on the images of the plurality of areas captured by the capturing step; a calculation step of calculating a range of a height of a focusing lens of the laser processing device corresponding to the dark area; and Recording step, record the result of the calculation step, The method for confirming the processing performance of the laser processing device also has the following time-dependent change confirmation step: taking the situation that a prescribed period of time has passed since the performance of the laser processing device was last confirmed as a condition, a series of steps including the processing mark forming step, the photographing step, the detecting step, the calculating step and the recording step are performed multiple times, and the results recorded in each recording step of the series of steps are compared, thereby confirming the time-dependent change of the processing performance of the laser processing device. In the temporal change checking step, a plurality of processing marks are formed using laser beams having different average outputs, and a range serving as a dark area is determined based on each average output of the laser beam.

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