Laser processing device

Abstract

This laser processing device comprises a control unit. The control unit executes: first movement processing for relatively moving a condenser lens in one direction along a first line; first oscillation processing for causing a light source to emit laser light during the first movement processing; second movement processing for relatively moving the condenser lens in a different direction along a second line; second oscillation processing for causing the light source to emit laser light during the second movement processing; and, between the first oscillation processing and the second oscillation processing, switching processing for switching at least one of a setting value of an output that is adjusted by an adjustment unit and a modulation pattern that is displayed by a spatial light modulator. The control unit starts the switching processing after completing the first oscillation processing during the first movement processing.

Description

Laser Processing Equipment

[0001] The present disclosure relates to a laser processing apparatus.

[0002] A laser processing device is known that cuts a wafer into multiple chips by moving the focal point of laser light along each of multiple lines set in a grid pattern on the object, and forming a modified region inside the object along each of the multiple lines (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2023-043342

[0004] In the laser beam device described above, for example, when the condenser lens is moved relatively from one line to another between adjacent lines, the laser beam irradiation conditions may be switched. In such a case, in order to shorten the takt time, it is important to efficiently move the condenser lens relatively from one line to the other while ensuring time for switching the laser beam irradiation conditions.

[0005] Therefore, an object of the present disclosure is to provide a laser processing device that can shorten the takt time.

[0006] A laser processing device according to one aspect of the present disclosure includes: [1] "a support unit that supports an object; a light source that oscillates laser light; an adjustment unit that adjusts an output of the laser light oscillated by the light source; a spatial light modulator that modulates the laser light oscillated by the light source; a condensing lens that condenses the laser light whose output has been adjusted by the adjustment unit and modulated by the spatial light modulator; and a control unit that controls at least the light source, the adjustment unit, and the spatial light modulator, wherein the control unit performs a first movement process to relatively move the condensing lens in one direction along the first line when forming modified regions along each of a first line and a second line set on the object by positioning a focal point of the laser light inside the object; and during the first movement process, a first oscillation process for causing the light source to oscillate the laser light so that the focal point moves relatively in the other direction along the second line; a second movement process for causing the light source to oscillate the laser light so that the focal point moves relatively in the other direction along the second line during the second movement process; and a switching process including at least one of a process for switching a set value of the output adjusted by the adjustment unit between the first oscillation process and the second oscillation process, and a process for switching a modulation pattern displayed by the spatial light modulator between the first oscillation process and the second oscillation process, wherein the control unit starts the switching process after finishing the first oscillation process during the first movement process.

[0007] In the laser processing apparatus described in [1] above, the control unit starts a switching process for switching the laser beam irradiation conditions after completing a first oscillation process for causing the light source to oscillate a laser beam during a first movement process for relatively moving the condenser lens in one direction along the first line. This allows the second oscillation process for causing the light source to oscillate a laser beam to start earlier during a second movement process for relatively moving the condenser lens in the other direction along the second line, compared to when the switching process is started after completing the first movement process. Therefore, the laser processing apparatus described in [1] above can shorten the takt time.

[0008] The laser processing device according to one aspect of the present disclosure may be [2] "the laser processing device according to the above [1], wherein the control unit further executes a stop process for stopping the relative movement of the condenser lens in the directions along the first line and the second line between the first movement process and the second movement process." According to the laser processing device according to [2], by adjusting the time of the stop process, the switching process for switching the irradiation conditions of the laser light can be reliably completed, thereby suppressing the occurrence of processing defects.

[0009] The laser processing device according to one aspect of the present disclosure may be [3] "the laser processing device described in the above [2], wherein the control unit further executes a third movement process during the stop process to relatively move the condenser lens from the end position of the first movement process to the start position of the second movement process." According to the laser processing device described in [3], the condenser lens can be reliably positioned at the start position of the second movement process, thereby suppressing the occurrence of processing defects.

[0010] The laser processing device according to one aspect of the present disclosure may be [4] "the laser processing device according to any one of [1] to [3] above, wherein the control unit executes the switching process between the first oscillation process and the second movement process." According to the laser processing device according to [4], the switching process for switching the laser light irradiation conditions can be reliably completed before the second oscillation process is started, thereby reducing takt time and suppressing the occurrence of processing defects.

[0011] A laser processing apparatus according to one aspect of the present disclosure may be the laser processing apparatus according to any one of [1] to [4] above, further including a detection unit for detecting the height of the surface of the object, wherein the control unit further executes a detection process for detecting the height along the first line during the first movement process, and the control unit starts a process for decelerating the relative movement of the focusing lens in the direction along the first line after completing the first oscillation process and the detection process as the first movement process. According to the laser processing apparatus according to [5], by starting the deceleration process after completing the first oscillation process, it is possible to further shorten the takt time. On the other hand, while starting the deceleration process may cause vibration, starting the deceleration process after completing the detection process can suppress the occurrence of vibration during the detection process, and as a result, it is possible to accurately detect the height of the surface of the object.

[0012] The laser processing device according to one aspect of the present disclosure may be [6] "the laser processing device according to any one of [1] to [5] above, wherein the control unit starts the switching process when the collecting lens is located inside the object as viewed from the optical axis direction of the collecting lens during the first movement process." The laser processing device according to [6] can shorten the takt time compared to waiting to start the switching process until the collecting lens is located outside the object as viewed from the optical axis direction of the collecting lens.

[0013] The laser processing device according to one aspect of the present disclosure may be [7] "the laser processing device according to any one of the above [1] to [6], wherein the control unit executes a process of relatively moving the condensing lens from a position along the first line to a position along the second line when the condensing lens is located outside the target object as viewed from the optical axis direction of the condensing lens." According to the laser processing device described in [7], the condensing lens can be reliably positioned at the start position of the second movement process, thereby suppressing the occurrence of processing defects.

[0014] According to the present disclosure, it is possible to provide a laser processing device that can shorten the takt time.

[0015] FIG. 1 is a perspective view of a laser processing apparatus according to an embodiment. FIG. 2 is a front view of a portion of the laser processing apparatus shown in FIG. 1. FIG. 3 is a front view of the laser processing head shown in FIG. 1. FIG. 4 is a side view of the laser processing head shown in FIG. 1. FIG. 5 is a configuration diagram of the laser processing head shown in FIG. 4. FIG. 6 is a configuration diagram of the attenuator shown in FIG. 5. FIG. 7 is a cross-sectional view of a portion of the spatial light modulator shown in FIG. 5. FIG. 8 is a plan view of the object shown in FIG. 1. FIG. 9 is a diagram showing a first processing example using the laser processing apparatus shown in FIG. 1. FIG. 10 is a diagram showing a first processing example in the first processing example shown in FIG. 9. FIG. 11 is a diagram showing a second processing example in the first processing example shown in FIG. 9. FIG. 12 is a diagram showing a second processing example using the laser processing apparatus shown in FIG. 1. FIG. 13 is a diagram showing a third processing example in the second processing example shown in FIG. 12. FIG. 14 is a diagram showing a fourth processing example in the second processing example shown in FIG. 12.

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted. [Configuration of laser processing device]

[0017] 1, the laser processing apparatus 1 includes a plurality of movement mechanisms 5 and 6, a support unit 7, a pair of laser processing heads 10A and 10B, a light source unit 8, and a control unit 9. Hereinafter, the first direction will be referred to as the Z direction, the second direction perpendicular to the first direction as the X direction, and the third direction perpendicular to both the first and second directions as the Y direction. In this embodiment, the Z direction is the vertical direction, and the X and Y directions are horizontal directions.

[0018] The movement mechanism 5 has a fixed part 51, a moving part 53, and an attachment part 55. The fixed part 51 is attached to the device frame 1a. The moving part 53 is attached to a rail provided on the fixed part 51 and can move along the Y direction. The attachment part 55 is attached to a rail provided on the moving part 53 and can move along the X direction.

[0019] The movement mechanism 6 has a fixed part 61, a pair of moving parts 63 and 64, and a pair of mounting parts 65 and 66. The fixed part 61 is attached to the device frame 1a. Each of the pair of moving parts 63 and 64 is attached to a rail provided on the fixed part 61, and each can move independently along the Y direction. The mounting part 65 is attached to a rail provided on the moving part 63, and can move along the Z direction. The mounting part 66 is attached to a rail provided on the moving part 64, and can move along the Z direction.

[0020] The support unit 7 is attached to a rotation shaft provided on the mounting unit 55 of the moving mechanism 5, and can rotate about an axis parallel to the Z direction. The support unit 7 supports the object 100. In this embodiment, the object 100 is a wafer.

[0021] 1 and 2 , the laser processing head 10A is attached to the attachment portion 65 of the moving mechanism 6. The laser processing head 10A faces the support portion 7 in the Z direction and irradiates the object 100 supported by the support portion 7 with laser light L. The laser processing head 10B is attached to the attachment portion 66 of the moving mechanism 6. The laser processing head 10B faces the support portion 7 in the Z direction and irradiates the object 100 supported by the support portion 7 with laser light L.

[0022] 1, the light source unit 8 has a pair of light sources 81, 82. The pair of light sources 81, 82 are attached to the device frame 1a. Each of the pair of light sources 81, 82 oscillates a laser beam L. The laser beam L emitted from the emission portion 81a of the light source 81 is guided to the laser processing head 10A by an optical fiber 2. The laser beam L emitted from the emission portion 82a of the light source 82 is guided to the laser processing head 10B by another optical fiber 2.

[0023] The control unit 9 controls each part of the laser processing apparatus 1 (such as the multiple movement mechanisms 5 and 6, the pair of laser processing heads 10A and 10B, and the light source unit 8). The control unit 9 is configured as a computer device including a processor, memory, storage, and communication devices. In the control unit 9, software (programs) loaded into the memory, etc., is executed by the processor, and the processor controls the reading and writing of data in the memory and storage, as well as communication via the communication devices. In this way, the control unit 9 realizes various functions. The control unit 9 has a display 91. The display 91 displays various information. The display 91 may be configured as a touch panel that accepts instructions input by the operator.

[0024] The laser processing apparatus 1 configured as described above can be used for various purposes, such as dicing to divide a wafer, slicing to thin a wafer, and trimming to remove the outer periphery of a wafer. Here, an example of processing using the laser processing apparatus 1 will be described. This example of processing is an example of forming modified regions inside the object 100, which is a wafer, along each of a plurality of lines set in a grid pattern in order to cut the object 100 into a plurality of chips (i.e., an example of the first half of a dicing process).

[0025] First, the movement mechanism 5 moves the support part 7 along both the X direction and the Y direction so that the support part 7 supporting the object 100 faces the pair of laser processing heads 10A, 10B in the Z direction. Next, the movement mechanism 5 rotates the support part 7 about an axis parallel to the Z direction as a center line so that multiple lines extending in one direction on the object 100 are aligned along the X direction.

[0026] Next, the movement mechanism 6 moves the laser processing head 10A along the Y direction so that the focal point of the laser light L emitted from the laser processing head 10A (hereinafter referred to as "laser light L of the laser processing head 10A") is located on one line extending in one direction. Meanwhile, the movement mechanism 6 moves the laser processing head 10B along the Y direction so that the focal point of the laser light L emitted from the laser processing head 10B (hereinafter referred to as "laser light L of the laser processing head 10B") is located on another line extending in one direction. Next, the movement mechanism 6 moves the laser processing head 10A along the Z direction so that the focal point of the laser light L of the laser processing head 10A is located inside the object 100. Meanwhile, the movement mechanism 6 moves the laser processing head 10B along the Z direction so that the focal point of the laser light L of the laser processing head 10B is located inside the object 100.

[0027] Next, the light source 81 emits the laser light L and the laser processing head 10A irradiates the object 100 with the laser light L, and the light source 82 emits the laser light L and the laser processing head 10B irradiates the object 100 with the laser light L. At the same time, the movement mechanism 5 moves the support part 7 along the X direction so that the focal point of the laser light L of the laser processing head 10A moves relatively along one line extending in one direction, and the focal point of the laser light L of the laser processing head 10B moves relatively along another line extending in the same direction. In this way, the laser processing apparatus 1 forms modified regions inside the object 100 along each of a plurality of lines extending in one direction on the object 100.

[0028] Next, the moving mechanism 5 rotates the support part 7 about an axis parallel to the Z direction as the center line so that a plurality of lines extending in another direction perpendicular to the one direction on the object 100 are aligned along the X direction.

[0029] Next, the movement mechanism 6 moves the laser processing head 10A along the Y direction so that the focal point of the laser light L of the laser processing head 10A is located on one line extending in the other direction. Meanwhile, the movement mechanism 6 moves the laser processing head 10B along the Y direction so that the focal point of the laser light L of the laser processing head 10B is located on another line extending in the other direction. Next, the movement mechanism 6 moves the laser processing head 10A along the Z direction so that the focal point of the laser light L of the laser processing head 10A is located inside the object 100. Meanwhile, the movement mechanism 6 moves the laser processing head 10B along the Z direction so that the focal point of the laser light L of the laser processing head 10B is located inside the object 100.

[0030] Next, the light source 81 emits the laser light L and the laser processing head 10A irradiates the object 100 with the laser light L, and the light source 82 emits the laser light L and the laser processing head 10B irradiates the object 100 with the laser light L. At the same time, the movement mechanism 5 moves the support part 7 along the X direction so that the focal point of the laser light L of the laser processing head 10A moves relatively along one line extending in the other direction and the focal point of the laser light L of the laser processing head 10B moves relatively along another line extending in the other direction. In this way, the laser processing apparatus 1 forms modified regions inside the object 100 along each of a plurality of lines extending in the other direction perpendicular to the one direction in the object 100.

[0031] In one example of the above processing, each of the pair of light sources 81, 82 emits laser light L that is transparent to the object 100, for example, by a pulse oscillation method. When such laser light L is focused inside the object 100, the laser light L is particularly absorbed in the portion corresponding to the focal point of the laser light L, forming a modified region inside the object 100. The modified region is a region whose density, refractive index, mechanical strength, and other physical properties differ from those of the surrounding unmodified region. Examples of modified regions include a melt-treated region, a crack region, a dielectric breakdown region, and a refractive index change region.

[0032] When the laser light L emitted by the pulse oscillation method is irradiated onto the object 100 and the focal point of the laser light L is moved relatively along a line set on the object 100, multiple modified spots are formed lined up in a row along the line. One modified spot is formed by irradiating one pulse of laser light L. A row of modified regions is a collection of multiple modified spots lined up in a row. Adjacent modified spots may be connected to each other or separated from each other depending on the relative moving speed of the focal point of the laser light L with respect to the object 100 and the repetition frequency of the laser light L. [Configuration of the laser processing head]

[0033] As shown in FIGS. 2, 3, and 4, the laser processing head 10A includes a housing 11, an incident portion 12, a laser beam adjusting portion 13, and a condenser lens 14.

[0034] The housing 11 has a first wall portion 21 and a second wall portion 22, a third wall portion 23 and a fourth wall portion 24, and a fifth wall portion 25 and a sixth wall portion 26. The first wall portion 21 and the second wall portion 22 face each other in the X direction. The third wall portion 23 and the fourth wall portion 24 face each other in the Y direction. The fifth wall portion 25 and the sixth wall portion 26 face each other in the Z direction.

[0035] The distance between the third wall portion 23 and the fourth wall portion 24 is smaller than the distance between the first wall portion 21 and the second wall portion 22. The distance between the first wall portion 21 and the second wall portion 22 is smaller than the distance between the fifth wall portion 25 and the sixth wall portion 26. The distance between the first wall portion 21 and the second wall portion 22 may be equal to the distance between the fifth wall portion 25 and the sixth wall portion 26, or may be larger than the distance between the fifth wall portion 25 and the sixth wall portion 26.

[0036] In the laser processing head 10A, the first wall 21 is located on the opposite side from the fixed portion 61 of the moving mechanism 6, and the second wall 22 is located on the fixed portion 61 side. The third wall 23 is located on the mounting portion 65 side of the moving mechanism 6, and the fourth wall 24 is located on the laser processing head 10B side opposite the mounting portion 65. The fifth wall 25 is located on the opposite side from the support portion 7, and the sixth wall 26 is located on the support portion 7 side.

[0037] The housing 11 is configured so that the housing 11 is attached to the mounting portion 65 with the third wall portion 23 positioned on the mounting portion 65 side of the movement mechanism 6. Specifically, the mounting portion 65 has a base plate 65a and a mounting plate 65b. The base plate 65a is attached to a rail provided on the movement portion 63. The mounting plate 65b is erected at the end of the base plate 65a on the laser processing head 10B side. The housing 11 is attached to the mounting portion 65 by threading the bolts 28 into the mounting plate 65b via the pedestals 27 with the third wall portion 23 in contact with the mounting plate 65b. The pedestals 27 are provided on both the first wall portion 21 and the second wall portion 22. The housing 11 is detachable from the mounting portion 65.

[0038] The incident portion 12 is disposed on the fifth wall portion 25. The incident portion 12 causes the laser light L to enter the housing 11. The incident portion 12 is biased toward the first wall portion 21 in the X direction and toward the fourth wall portion 24 in the Y direction. In other words, the distance between the incident portion 12 and the first wall portion 21 in the X direction is smaller than the distance between the incident portion 12 and the second wall portion 22 in the X direction, and the distance between the incident portion 12 and the fourth wall portion 24 in the Y direction is smaller than the distance between the incident portion 12 and the third wall portion 23 in the X direction.

[0039] The incident portion 12 is connected to the output end 2a of the optical fiber 2. Specifically, the incident portion 12 is a portion including a hole 25a formed in the fifth wall portion 25. The fifth wall portion 25 is provided with an attachment portion 25b. The main body portion 2b of the output end 2a is attached to the attachment portion 25b with a bolt or the like. In this state, the tip portion 2c of the output end 2a passes through the hole 25a. This makes the output end 2a of the optical fiber 2 detachable from the incident portion 12. A cover 25c is disposed between the fifth wall portion 25 and the main body portion 2b. The cover 25c covers the gap formed between the hole 25a and the tip portion 2c. As an example, at the output end 2a, an isolator that suppresses returning light is disposed in the main body portion 2b, and a collimator lens that collimates the laser light L is disposed in the tip portion 2c. The incident portion 12 may be a connector or the like configured to be connectable to the output end 2a of the optical fiber 2.

[0040] The laser beam adjustment unit 13 is disposed within the housing 11. The laser beam adjustment unit 13 adjusts the laser beam L incident from the incident unit 12. The laser beam adjustment unit 13 is disposed within the housing 11 on the fourth wall 24 side with respect to the partition wall 29. The laser beam adjustment unit 13 is attached to the partition wall 29. The partition wall 29 is provided within the housing 11 and divides the area within the housing 11 into an area on the third wall 23 side and an area on the fourth wall 24 side. The partition wall 29 is configured as a part of the housing 11. Each component of the laser beam adjustment unit 13 is attached to the partition wall 29 on the fourth wall 24 side. The partition wall 29 functions as an optical base that supports each component of the laser beam adjustment unit 13.

[0041] The condensing lens 14 is disposed on the sixth wall portion 26. Specifically, the condensing lens 14 is disposed on the sixth wall portion 26, passing through a hole 26a (see FIG. 5 ) formed in the sixth wall portion 26. The condensing lens 14 condenses the laser light L adjusted by the laser light adjustment unit 13 and emits the laser light L to the outside of the housing 11. The condensing lens 14 is biased toward the second wall portion 22 in the X direction and toward the fourth wall portion 24 in the Y direction. In other words, the distance between the condensing lens 14 and the second wall portion 22 in the X direction is smaller than the distance between the condensing lens 14 and the first wall portion 21 in the X direction, and the distance between the condensing lens 14 and the fourth wall portion 24 in the Y direction is smaller than the distance between the condensing lens 14 and the third wall portion 23 in the X direction.

[0042] As shown in FIG. 5 , the laser beam adjusting unit 13 includes a reflecting unit 31, an attenuator (adjusting unit) 32, and a reflecting unit 33. The reflecting unit 31, the attenuator 32, and the reflecting unit 33 are arranged on a first straight line SL1 extending along the X direction. The reflecting unit 31 faces the incident unit 12 in the Z direction. That is, the reflecting unit 31 faces the output end 2a of the optical fiber 2 in the Z direction. The reflecting unit 31 reflects the laser beam L incident from the incident unit 12 toward the second wall unit 22. The attenuator 32 adjusts the output of the laser beam L reflected by the reflecting unit 31. That is, the attenuator 32 adjusts the output of the laser beam L oscillated by the light source 81. The reflecting unit 33 reflects the laser beam L, the output of which has been adjusted by the attenuator 32, toward the sixth wall unit 26. Each of the reflecting units 31 and 33 is, for example, a mirror or a prism.

[0043] The laser light adjusting unit 13 further includes a beam expander 34 and a reflecting unit 35. The reflecting unit 33, the beam expander 34, and the reflecting unit 35 are arranged on a second straight line SL2 extending along the Z direction. The beam expander 34 expands the diameter of the laser light L reflected by the reflecting unit 33. The reflecting unit 35 reflects the laser light L, the diameter of which has been expanded by the beam expander 34, toward the first wall unit 21 and the fifth wall unit 25. The reflecting unit 35 is, for example, a mirror or a prism.

[0044] The laser beam adjusting unit 13 further includes a spatial light modulator 36 and an imaging optical system 37. The spatial light modulator 36, the imaging optical system 37, and the condenser lens 14 are arranged on a third straight line SL3 extending along the Z direction. The spatial light modulator 36 modulates the laser beam L reflected by the reflecting unit 35. That is, the spatial light modulator 36 modulates the laser beam L emitted by the light source 81. The spatial light modulator 36 is a reflective spatial light modulator that modulates the laser beam L and reflects it toward the sixth wall portion 26. The spatial light modulator 36 is, for example, an LCOS (Liquid Crystal on Silicon)-SLM (Spatial Light Modulator). The imaging optical system 37 forms a double-telecentric optical system in which the reflecting surface 36a of the spatial light modulator 36 and the entrance pupil plane 14a of the condenser lens 14 are in an imaging relationship. The imaging optical system 37 is composed of multiple lenses. The condenser lens 14 condenses the laser light L whose output has been adjusted by the attenuator 32 and whose output has been modulated by the spatial light modulator 36 .

[0045] The first line SL1, the second line SL2, and the third line SL3 are located on the same plane perpendicular to the Y direction. The second line SL2 is located on the second wall portion 22 side of the third line SL3. In the laser processing head 10A, the laser light L incident on the entrance portion 12 into the housing 11 along the Z direction is reflected by the reflecting portion 31 and travels along the first line SL1. The laser light L traveling along the first line SL1 is reflected by the reflecting portion 33 and travels along the second line SL2. The laser light L traveling along the second line SL2 is sequentially reflected by the reflecting portion 35 and the spatial light modulator 36 and travels along the third line SL3. The laser light L traveling along the third line SL3 is emitted from the focusing lens 14 to the outside of the housing 11 along the Z direction.

[0046] The laser processing head 10A further includes a dichroic mirror 15, an observation unit 16, a distance measurement unit (detection unit) 17, a drive unit 18, and a circuit unit 19.

[0047] The dichroic mirror 15 is disposed on the third straight line SL3 between the imaging optical system 37 and the condenser lens 14. That is, the dichroic mirror 15 is disposed within the housing 11 between the laser light adjustment unit 13 and the condenser lens 14. The dichroic mirror 15 is attached to the partition wall 29 on the side of the fourth wall 24. The dichroic mirror 15 transmits the laser light L. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 is preferably, for example, a cube type or a type of two plates arranged to have a twisted relationship.

[0048] The observation unit 16 is disposed within the housing 11 on the first wall 21 side with respect to the third straight line SL3. That is, the observation unit 16 is disposed on the first wall 21 side with respect to the condenser lens 14 in the X direction. The observation unit 16 is attached to the partition wall 29 on the fourth wall 24 side. The observation unit 16 irradiates the surface of the object 100 with observation light L10 (e.g., visible light) for observing the surface of the object 100 (e.g., the surface on the side where the laser light L is incident), and detects the observation light L10 reflected by the surface of the object 100.

[0049] In this embodiment, the observation light L10 emitted from the observation unit 16 is reflected successively by the beam splitter 20 and the dichroic mirror 15, passes through the condenser lens 14, exits the housing 11, and is irradiated onto the surface of the object 100. The observation light L10 reflected by the surface of the object 100 passes through the condenser lens 14 and enters the housing 11, is reflected successively by the dichroic mirror 15 and the beam splitter 20, and enters the observation unit 16. The beam splitter 20 is attached to the partition wall 29 on the fourth wall 24 side.

[0050] The distance measuring unit 17 is disposed within the housing 11 on the first wall 21 side with respect to the third straight line SL3. That is, the distance measuring unit 17 is disposed on the first wall 21 side with respect to the condensing lens 14 in the X direction. The distance measuring unit 17 is attached to the partition wall 29 on the fourth wall 24 side. The distance measuring unit 17 irradiates the surface of the object 100 with distance measuring light L20 (e.g., laser light) to measure the distance between the surface of the object 100 (e.g., the surface on which the laser light L is incident) and the condensing lens 14, and detects the distance measuring light L20 reflected by the surface of the object 100. In this way, the distance measuring unit 17 detects the height (position in the Z direction) of the surface of the object 100.

[0051] In this embodiment, the distance measurement light L20 emitted from the distance measurement unit 17 passes through the beam splitter 20, is reflected by the dichroic mirror 15, passes through the condenser lens 14, is emitted outside the housing 11, and is irradiated onto the surface of the object 100. The distance measurement light L20 reflected by the surface of the object 100 passes through the condenser lens 14 and enters the housing 11, is reflected by the dichroic mirror 15, passes through the beam splitter 20, and is incident on the distance measurement unit 17. The wavelengths of the laser light L, the distance measurement light L20, and the observation light L10 are different from one another (at least their respective center wavelengths are shifted from one another).

[0052] The drive unit 18 is attached to the partition wall 29 on the side of the fourth wall 24. The drive unit 18 moves the condenser lens 14 arranged on the sixth wall 26 in the Z direction by, for example, the driving force of a piezoelectric element.

[0053] As shown in FIGS. 3 and 5 , the circuit unit 19 is disposed within the housing 11 on the third wall 23 side relative to the partition wall 29. That is, the circuit unit 19 is disposed within the housing 11 on the third wall 23 side relative to the laser light adjustment unit 13, the distance measurement unit 17, and the observation unit 16. The circuit unit 19 is spaced apart from the partition wall 29. The circuit unit 19 may be, for example, a plurality of circuit boards. The circuit unit 19 processes signals output from the distance measurement unit 17 and signals input to the spatial light modulator 36. The circuit unit 19 controls the driver 18 based on the signals output from the distance measurement unit 17. As an example, the circuit unit 19 controls the driver 18 based on the signals output from the distance measurement unit 17 so that the distance between the surface of the object 100 and the focusing lens 14 is maintained constant (i.e., so that the distance between the surface of the object 100 and the focusing point of the laser light L is maintained constant).

[0054] The partition wall 29 is formed with notches, holes, etc. (not shown) through which wires pass for electrically connecting the observation unit 16, the distance measurement unit 17, the drive unit 18, and the spatial light modulator 36 to the circuit unit 19. The housing 11 is also provided with a connector (not shown) to which wires, etc., for electrically connecting the circuit unit 19 to the control unit 9 are connected.

[0055] Like the laser processing head 10A, the laser processing head 10B includes a housing 11, an incident section 12, a laser light adjustment section 13, a condenser lens 14, a dichroic mirror 15, an observation section 16, a distance measurement section 17, a drive section 18, and a circuit section 19. However, as shown in Fig. 2, the components of the laser processing head 10B are arranged so as to have a plane-symmetric relationship with the components of the laser processing head 10A with respect to an imaginary plane that passes through the midpoint between the pair of mounting sections 65, 66 and is perpendicular to the Y direction.

[0056] For example, the housing 11 of the laser processing head 10A is attached to the mounting portion 65 so that the fourth wall portion 24 is located on the laser processing head 10B side relative to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25. In contrast, the housing 11 of the laser processing head 10B is attached to the mounting portion 66 so that the fourth wall portion 24 is located on the laser processing head 10A side relative to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25.

[0057] The housing 11 of the laser processing head 10B is configured so that the housing 11 is attached to the attachment portion 66 with the third wall portion 23 positioned on the attachment portion 66 side. Specifically, it is as follows. The attachment portion 66 has a base plate 66a and an attachment plate 66b. The base plate 66a is attached to a rail provided on the moving portion 63. The attachment plate 66b is erected at the end of the base plate 66a on the laser processing head 10A side. The housing 11 of the laser processing head 10B is attached to the attachment portion 66 with the third wall portion 23 in contact with the attachment plate 66b. The housing 11 of the laser processing head 10B is detachable from the attachment portion 66. [Configuration of the Attenuator]

[0058] As shown in FIG. 6 , the attenuator 32 includes a λ / 2 wave plate 321 and a polarizing beam splitter 322. The λ / 2 wave plate 321 can rotate about a first straight line SL1. When laser light L is incident on the λ / 2 wave plate 321 with its polarization direction tilted by an angle θ with respect to its optical axis (e.g., fast axis), the λ / 2 wave plate 321 rotates the polarization direction by an angle 2θ about the first straight line SL1 and emits the laser light L. When laser light L emitted from the λ / 2 wave plate 321 is incident on the polarizing beam splitter 322, the polarizing beam splitter 322 transmits the P-polarized component that coincides with the polarization axis of the polarizing plate 342 as laser light L along the first straight line SL1 and reflects the S-polarized component. As an example, the polarizing beam splitter 322 is a cube-type optical element having an optical surface 322a tilted by a predetermined angle (e.g., Brewster angle).

[0059] In the attenuator 32 configured as described above, the λ / 2 wave plate 321 is rotated about the first straight line SL1 by a rotation mechanism (not shown) including an actuator, thereby adjusting the output of the laser light L (i.e., the P-polarized component transmitted through the polarizing beam splitter 322) emitted from the polarizing beam splitter 322. In this way, the attenuator 32 can adjust the output of the laser light L by appropriately setting the direction of the optical axis of the λ / 2 wave plate 321. The control unit 9 controls the rotation mechanism to switch the direction of the optical axis of the λ / 2 wave plate 321, thereby performing a process of switching the set value of the output of the laser light L adjusted by the attenuator 32 (hereinafter referred to as "output switching process"). [Configuration of Spatial Light Modulator]

[0060] As shown in Figure 7, the spatial light modulator 36 is constructed by stacking a drive circuit layer 362, a pixel electrode layer 363, a reflective film 364, an orientation film 365, a liquid crystal layer 366, an orientation film 367, a transparent conductive film 368, and a transparent substrate 369 in this order on a semiconductor substrate 361.

[0061] The semiconductor substrate 361 is, for example, a silicon substrate. The drive circuit layer 362 forms an active matrix circuit on the semiconductor substrate 361. The pixel electrode layer 363 includes a plurality of pixel electrodes 363a arranged in a matrix along the surface of the semiconductor substrate 361. Each pixel electrode 363a is formed of, for example, a metal material such as aluminum. A voltage is applied to each pixel electrode 363a by the drive circuit layer 362.

[0062] The reflective film 364 is, for example, a dielectric multilayer film. The alignment film 365 is provided on the surface of the liquid crystal layer 366 facing the reflective film 364, and the alignment film 367 is provided on the surface of the liquid crystal layer 366 opposite the reflective film 364. Each of the alignment films 365, 367 is formed from, for example, a polymer material such as polyimide, and the surfaces of each of the alignment films 365, 367 that come into contact with the liquid crystal layer 366 are subjected to, for example, rubbing treatment. The alignment films 365, 367 align liquid crystal molecules 366a contained in the liquid crystal layer 366 in a fixed direction.

[0063] The transparent conductive film 368 is provided on the surface of the transparent substrate 369 on the alignment film 367 side, and faces the pixel electrode layer 363 with the liquid crystal layer 366 and the like sandwiched therebetween. The transparent substrate 369 is, for example, a glass substrate. The transparent conductive film 368 is formed of, for example, a light-transmitting and conductive material such as ITO. The transparent substrate 369 and the transparent conductive film 368 transmit the laser light L.

[0064] In the spatial light modulator 36 configured as described above, when a signal indicating a modulation pattern is input from the control unit 9 to the drive circuit layer 362, a voltage corresponding to the signal is applied to each pixel electrode 363a, and an electric field is formed between each pixel electrode 363a and the transparent conductive film 368. When this electric field is formed, the alignment direction of the liquid crystal molecules 216a in the liquid crystal layer 366 changes for each region corresponding to each pixel electrode 363a, and the refractive index changes for each region corresponding to each pixel electrode 363a. This state is the state in which the modulation pattern is displayed on the liquid crystal layer 366.

[0065] With a modulation pattern displayed on the liquid crystal layer 366, laser light L enters the liquid crystal layer 366 from the outside through the transparent substrate 369 and the transparent conductive film 368, is reflected by the reflective film 364, and is emitted from the liquid crystal layer 366 to the outside through the transparent conductive film 368 and the transparent substrate 369. The laser light L is modulated according to the modulation pattern displayed on the liquid crystal layer 366. In this way, the spatial light modulator 36 can appropriately set the modulation pattern displayed on the liquid crystal layer 366 to modulate the laser light L (e.g., modulate the intensity, amplitude, phase, polarization, etc. of the laser light L). The control unit 9 switches the signal input to the drive circuit layer 362 to perform a process of switching the modulation pattern displayed by the spatial light modulator 36 (hereinafter referred to as a "modulation pattern switching process"). [Configuration of the Target]

[0066] 8, the target object 100 is a wafer and has a first surface 100a and a second surface 100b opposite to the first surface 100a. The target object 100 is configured by stacking a functional device layer 102 on a semiconductor substrate 101.

[0067] The semiconductor substrate 101 is, for example, a silicon substrate. The semiconductor substrate 101 has a first surface 101a and a second surface 101b opposite to the first surface 101a. The second surface 101b of the semiconductor substrate 101 is the second surface 100b of the object 100. The semiconductor substrate 101 is provided with a notch 101c indicating the crystal orientation. Note that the semiconductor substrate 101 may be provided with an orientation flat instead of the notch 101c.

[0068] The functional device layer 102 is provided on the first surface 101a of the semiconductor substrate 101. The functional device layer 102 includes a plurality of functional devices 102a arranged in a matrix along the first surface 101a of the semiconductor substrate 101. Each functional device 102a is, for example, a light-receiving device such as a photodiode, a light-emitting device such as a laser diode, or a circuit device such as a memory. Each functional device 102a may be configured three-dimensionally by stacking a plurality of layers.

[0069] The object 100 is cut into each functional element 102a along each of the multiple lines 150. The multiple lines 150 are set in a grid pattern on the object 100 so as to pass between each of the multiple functional elements 102a when viewed from the thickness direction of the object 100. Each line 150 is a virtual line set on the object 100 by the laser processing device 1. Note that each line 150 may also be a line that is actually drawn on the object 100. [First Processing Example Using Laser Processing Device]

[0070] A first processing example will be described in which the "object 100 shown in FIG. 8" is processed using the "laser processing apparatus 1 shown in FIG. 1." As shown in (a) and (b) of FIG. 9, the first processing example is a case in which the second surface 100b is used as the incident surface of the laser light L, and the focal point P of the laser light L is positioned inside the object 100, thereby forming modified regions 110 along first lines 151 and second lines 152 set on the object 100. In the first processing example, the first lines 151 and second lines 152 are aligned in the Z direction (i.e., the thickness direction of the object 100, which is a wafer). The first lines 151 and second lines 152 each extend along the corresponding line 150 and, for example, coincide with the corresponding line 150 when viewed from the Z direction (see FIG. 8).

[0071] In the first processing example, first, as shown in (a) of FIG. 9 , the condenser lens 14 is relatively moved in one direction in the X direction along a first line 151 on the first surface 100a side, and the focal point P is relatively moved in one direction in the X direction along the first line 151. As a result, a modified region 110 is formed along the first line 151. At this time, the distance measuring unit 17 detects the height of the second surface 100b along the first line 151. Next, as shown in (b) of FIG. 9 , the condenser lens 14 is relatively moved in the other direction in the X direction (the opposite direction from the one direction) along a second line 152 on the second surface 100b side, and the focal point P is relatively moved in the other direction in the X direction along the second line 152. As a result, a modified region 110 is formed along the second line 152. At this time, the distance measuring unit 17 detects the height of the second surface 100b along the second line 152.

[0072] The height of the second surface 100b is detected in an effective region 104, which is an area inside the bevel portion 103 (i.e., the outer periphery of the semiconductor substrate 101) of the object 100. The modified region 110 is formed in a formation region 105, which is an area of ​​the effective region 104 where the functional element layer 102 is formed.

[0073] The relative movement of the focusing lens 14 and the focusing point P in the direction parallel to the first line 151 and the second line 152 is relative movement with respect to the object 100, and in the laser processing apparatus 1, this is achieved by the movement mechanism 5 moving the support part 7 in the X direction (see FIG. 1 ). The relative movement of the focusing lens 14 and the focusing point P in the direction perpendicular to the first line 151 and the second line 152 is relative movement with respect to the object 100, and in the laser processing apparatus 1, this is achieved by the movement mechanism 6 moving each of the laser processing heads 10A, 10B in the Y direction and the Z direction (see FIG. 1 ).

[0074] Hereinafter, a first processing example and a second processing example performed in the first processing example will be described. The first processing example and the second processing example are performed by the control unit 9 controlling each part of the laser processing apparatus 1 (at least the light source 81, the attenuator 32, the spatial light modulator 36, and the distance measurement unit 17). Here, the case where the laser light L oscillated by the light source 81 is emitted from the laser processing head 10A will be described, but the same applies to the case where the laser light L oscillated by the light source 82 is emitted from the laser processing head 10B. [First Processing Example]

[0075] 10 , the control unit 9 executes a first movement process MP1. The first movement process MP1 is a process of relatively moving the condenser lens 14 in one direction in the X direction along the first line 151. During the first movement process MP1, the control unit 9 executes a first detection process (detection process) DP1 and a first oscillation process OP1. The first detection process DP1 is a process of detecting the height of the second surface 100b along the first line 151. The first oscillation process OP1 is a process of causing the light source 81 to oscillate laser light L so that the focal point P moves relatively in one direction in the X direction along the first line 151.

[0076] The positions are as follows: The first movement process MP1 is performed from a position on one side outside the object 100 in the X direction to a position on the other side outside the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the first movement process MP1 based on preset coordinate information. The first detection process DP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the effective area 104 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first detection process DP1 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the first detection process DP1 based on changes in the light intensity detected by the distance measurement unit 17. The first oscillation process OP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the formation area 105 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first oscillation process OP1 based on preset coordinate information.

[0077] The timing is as follows: The control unit 9 starts the first movement process MP1 by outputting an operation start signal to the movement mechanism 5 at t1, and ends the first movement process MP1 by outputting an operation end signal to the movement mechanism 5 at t6. The control unit 9 starts the first detection process DP1 by outputting an operation start signal to the distance measurement unit 17 at t2, and ends the first detection process DP1 by outputting an operation end signal to the distance measurement unit 17 at t5. The control unit 9 starts the first oscillation process OP1 by outputting an operation start signal to the light source 81 at t3, and ends the first oscillation process OP1 by outputting an operation end signal to the light source 81 at t4. Note that t1, t2, t3, t4, t5, and t6 are arranged chronologically in this order.

[0078] The above-mentioned t4 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal that switches the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal that switches the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0079] The control unit 9 executes a second movement process MP2 after a predetermined time has elapsed since the first movement process MP1. The second movement process MP2 is a process of relatively moving the condenser lens 14 in the other direction in the X direction along the second line 152. The control unit 9 executes a second detection process DP2 and a second oscillation process OP2 during the second movement process MP2. The second detection process DP2 is a process of detecting the height of the second surface 100b along the second line 152. The second oscillation process OP2 is a process of causing the light source 81 to oscillate the laser light L so that the focal point P moves relatively along the second line 152 in the other direction in the X direction.

[0080] The positions are as follows: The second movement process MP2 is performed from a position on the other side of the object 100 in the X direction to a position on one side of the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the second movement process MP2 based on preset coordinate information. The second detection process DP2 is performed between a pair of intersections where the second line 152 and the outer edge of the effective area 104 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second detection process DP2 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the second detection process DP2 based on a change in the light amount detected by the distance measurement unit 17. The second oscillation process OP2 is performed between a pair of intersections where the second line 152 and the outer edge of the formation area 105 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second oscillation process OP2 based on preset coordinate information.

[0081] The timing is as follows: The control unit 9 starts the second movement process MP2 by outputting an operation start signal to the movement mechanism 5 at t7, and ends the second movement process MP2 by outputting an operation end signal to the movement mechanism 5 at t12. The control unit 9 starts the second detection process DP2 by outputting an operation start signal to the distance measurement unit 17 at t8, and ends the second detection process DP2 by outputting an operation end signal to the distance measurement unit 17 at t11. The control unit 9 starts the second oscillation process OP2 by outputting an operation start signal to the light source 81 at t9, and ends the second oscillation process OP2 by outputting an operation end signal to the light source 81 at t10. Note that t7, t8, t9, t10, t11, and t12 are arranged chronologically in this order.

[0082] The above-mentioned t10 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal that switches the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal that switches the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0083] The control unit 9 executes a stop process SP between the first movement process MP1 and the second movement process MP2 (i.e., between t6 and t7). The stop process SP is a process for stopping the relative movement of the condenser lens 14 in the directions along the first line 151 and the second line 152. The control unit 9 executes a third movement process MP3 during the stop process SP. The third movement process MP3 is a process for relatively moving the condenser lens 14 from the end position of the first movement process MP1 to the start position of the second movement process MP2. The control unit 9 executes a process for relatively moving the condenser lens 14 from a position along the first line 151 to a position along the second line 152 when the condenser lens 14 is located outside the target object 100 when viewed from the optical axis direction of the condenser lens 14. In addition, the control unit 9 determines whether the focusing lens 14 is located inside or outside the object 100 when viewed from the optical axis direction of the focusing lens 14 based on pre-set coordinate information or based on changes in the amount of light detected by the distance measurement unit 17.

[0084] As described above, the end position of the first movement process MP1 is a position along the first line 151 on the other side outside the object 100 in the X direction. The start position of the second movement process MP2 is a position along the second line 152 on the other side outside the object 100 in the X direction. In other words, the end position of the first movement process MP1 and the start position of the second movement process MP2 differ in the Z direction. The control unit 9 starts the third movement process MP3 by outputting an operation start signal for the movement mechanism 6 after t6 (i.e., simultaneously with or thereafter) when the operation end signal for the movement mechanism 5 is output, and ends the third movement process MP3 by outputting an operation end signal for the movement mechanism 6 before t7 (i.e., simultaneously with or before) when the operation start signal for the movement mechanism 5 is output.

[0085] The control unit 9 executes a switching process CP between the first oscillation process OP1 and the second oscillation process OP2 (i.e., between t4 and t9). The switching process CP includes an output switching process and a modulation pattern switching process. As described above, the output switching process is a process for switching the set value of the output of the laser light L adjusted by the attenuator 32. The modulation pattern switching process is a process for switching the modulation pattern displayed by the spatial light modulator 36. As an example, the output switching process is executed so that the output of the laser light is lower during the first oscillation process OP1 than during the second oscillation process OP2, and the modulation pattern switching process is executed so that the degree of aberration correction is weakened during the first oscillation process OP1 than during the second oscillation process OP2.

[0086] During the first movement process MP1, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 (i.e., between t4 and t6). In the first processing example, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 and before completing the first detection process DP1 (i.e., between t4 and t5). That is, during the first movement process MP1, the control unit 9 starts the switching process CP when the condenser lens 14 is positioned within the object 100 when viewed from the optical axis direction of the condenser lens 14. The control unit 9 starts the switching process CP by outputting an operation start signal to the attenuator 32 and a modulation pattern switching signal to the spatial light modulator 36, for example, triggered by the timing when the control unit 9 outputs an operation end signal to the light source 81. The switching process CP ends when the switching of the direction of the optical axis of the λ / 2 wave plate 321 in the attenuator 32 is completed and the switching of the modulation pattern displayed on the liquid crystal layer 366 in the spatial light modulator 36 is completed, and an end instruction signal is not output from the control unit 9 to each of the attenuator 32 and the spatial light modulator 36.

[0087] As an example, the time (e.g., about 0.2 seconds) required to switch the modulation pattern displayed on the liquid crystal layer 366 in the spatial light modulator 36 is longer than the time (e.g., about 0.05 to 0.1 seconds) required to switch the direction of the optical axis of the λ / 2 wave plate 321 in the attenuator 32. Therefore, the control unit 9 adjusts the timing of each process (especially t6 and t7) based on the longest time required to switch the irradiation conditions of the laser light L so that the switching process CP is completed at least before the second oscillation process OP2.

[0088] In the first movement process MP1 described above, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the first line 151 before starting the first oscillation process OP1 and the first detection process DP1, and after ending the first oscillation process OP1 and the first detection process DP1, starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the first line 151. Also, in the second movement process MP2 described above, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the second line 152 before starting the second oscillation process OP2 and the second detection process DP2, and starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the second line 152 after ending the second oscillation process OP2 and the second detection process DP2. [Second Processing Example]

[0089] 11 , the control unit 9 executes a first movement process MP1. The first movement process MP1 is a process of relatively moving the condenser lens 14 in one direction in the X direction along the first line 151. The control unit 9 executes a first detection process DP1 and a first oscillation process OP1 during the first movement process MP1. The first detection process DP1 is a process of detecting the height of the second surface 100b along the first line 151. The first oscillation process OP1 is a process of causing the light source 81 to oscillate laser light L so that the focal point P moves relatively in one direction in the X direction along the first line 151.

[0090] The positions are as follows: The first movement process MP1 is performed from a position on one side outside the object 100 in the X direction to a position on the other side outside the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the first movement process MP1 based on preset coordinate information. The first detection process DP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the effective area 104 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first detection process DP1 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the first detection process DP1 based on changes in the light intensity detected by the distance measurement unit 17. The first oscillation process OP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the formation area 105 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first oscillation process OP1 based on preset coordinate information.

[0091] The timing is as follows: The control unit 9 starts the first movement process MP1 by outputting an operation start signal to the movement mechanism 5 at t21, and ends the first movement process MP1 by outputting an operation end signal to the movement mechanism 5 at t26. The control unit 9 starts the first detection process DP1 by outputting an operation start signal to the distance measurement unit 17 at t22, and ends the first detection process DP1 by outputting an operation end signal to the distance measurement unit 17 at t25. The control unit 9 starts the first oscillation process OP1 by outputting an operation start signal to the light source 81 at t23, and ends the first oscillation process OP1 by outputting an operation end signal to the light source 81 at t24. Note that t21, t22, t23, t24, t25, and t26 are arranged chronologically in this order.

[0092] The above-mentioned t24 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal that switches the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal that switches the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0093] Following the first movement process MP1, the control unit 9 executes a second movement process MP2. The second movement process MP2 is a process of relatively moving the condenser lens 14 in the other direction in the X direction along the second line 152. During the second movement process MP2, the control unit 9 executes a second detection process DP2 and a second oscillation process OP2. The second detection process DP2 is a process of detecting the height of the second surface 100b along the second line 152. The second oscillation process OP2 is a process of causing the light source 81 to oscillate laser light L so that the focal point P moves relatively along the second line 152 in the other direction in the X direction.

[0094] The positions are as follows: The second movement process MP2 is performed from a position on the other side of the object 100 in the X direction to a position on one side of the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the second movement process MP2 based on preset coordinate information. The second detection process DP2 is performed between a pair of intersections where the second line 152 and the outer edge of the effective area 104 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second detection process DP2 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the second detection process DP2 based on a change in the light amount detected by the distance measurement unit 17. The second oscillation process OP2 is performed between a pair of intersections where the second line 152 and the outer edge of the formation area 105 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second oscillation process OP2 based on preset coordinate information.

[0095] The timing is as follows: The control unit 9 starts the second movement process MP2 by outputting an operation start signal to the movement mechanism 5 at t26, and ends the second movement process MP2 by outputting an operation end signal to the movement mechanism 5 at t31. The control unit 9 starts the second detection process DP2 by outputting an operation start signal to the distance measurement unit 17 at t27, and ends the second detection process DP2 by outputting an operation end signal to the distance measurement unit 17 at t30. The control unit 9 starts the second oscillation process OP2 by outputting an operation start signal to the light source 81 at t28, and ends the second oscillation process OP2 by outputting an operation end signal to the light source 81 at t29. Note that t26, t27, t28, t29, t30, and t31 are arranged chronologically in this order.

[0096] The above-mentioned t29 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal to switch the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal to switch the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0097] The control unit 9 executes a third movement process MP3 between the first detection process DP1 and the second detection process DP2. The third movement process MP3 is a process for relatively moving the condenser lens 14 from a position along the first line 151 to a position along the second line 152. In the second processing example, the "relative movement of the condenser lens 14 in the Z direction" by the third movement process MP3 is performed simultaneously with the "relative movement of the condenser lens 14 to one side in the X direction" by the first movement process MP1 and the "relative movement of the condenser lens 14 to the other side in the X direction" by the second movement process MP2.

[0098] The control unit 9 executes a switching process CP between the first oscillation process OP1 and the second oscillation process OP2 (i.e., between t24 and t28). The switching process CP includes an output switching process and a modulation pattern switching process. As described above, the output switching process is a process for switching the set value of the output of the laser light L adjusted by the attenuator 32. The modulation pattern switching process is a process for switching the modulation pattern displayed by the spatial light modulator 36. As an example, the output switching process is executed so that the output of the laser light is lower during the first oscillation process OP1 than during the second oscillation process OP2, and the modulation pattern switching process is executed so that the degree of aberration correction is weakened during the first oscillation process OP1 than during the second oscillation process OP2.

[0099] During the first movement process MP1, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 (i.e., between t24 and t26). In the second processing example, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 and before completing the first detection process DP1 (i.e., between t24 and t25). That is, during the first movement process MP1, the control unit 9 starts the switching process CP when the condenser lens 14 is positioned within the object 100 when viewed from the optical axis direction of the condenser lens 14. The control unit 9 starts the switching process CP by outputting an operation start signal to the attenuator 32 and a modulation pattern switching signal to the spatial light modulator 36, for example, triggered by the timing when the control unit 9 outputs an operation end signal to the light source 81. The switching process CP ends when the switching of the direction of the optical axis of the λ / 2 wave plate 321 in the attenuator 32 is completed and the switching of the modulation pattern displayed on the liquid crystal layer 366 in the spatial light modulator 36 is completed, and an end instruction signal is not output from the control unit 9 to each of the attenuator 32 and the spatial light modulator 36.

[0100] As an example, the time (e.g., about 0.2 seconds) required to switch the modulation pattern displayed on the liquid crystal layer 366 in the spatial light modulator 36 is longer than the time (e.g., about 0.05 to 0.1 seconds) required to switch the direction of the optical axis of the λ / 2 wave plate 321 in the attenuator 32. Therefore, the control unit 9 adjusts the timing of each process (particularly t26) based on the longest time required to switch the irradiation conditions of the laser light L so that the switching process CP is completed at least before the second oscillation process OP2.

[0101] In the above-described first movement process MP1, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the first line 151 before starting the first oscillation process OP1 and the first detection process DP1, and after completing the first oscillation process OP1 and the first detection process DP1, starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the first line 151. Also, in the above-described second movement process MP2, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the second line 152 before starting the second oscillation process OP2 and the second detection process DP2, and starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the second line 152 after completing the second oscillation process OP2 and the second detection process DP2. [Second Processing Example Using Laser Processing Apparatus]

[0102] A second processing example will be described in which the "object 100 shown in FIG. 8" is processed by the "laser processing apparatus 1 shown in FIG. 1." As shown in (a) and (b) of FIG. 12, the second processing example is a case in which the second surface 100b is used as the incident surface of the laser light L, and the focal point P of the laser light L is positioned inside the object 100, thereby forming a modified region 110 along each of a first line 151 and a second line 152 set on the object 100. In the second processing example, the first line 151 and the second line 152 are aligned in the Y direction. The first line 151 extends along one of a pair of adjacent lines 150 and, for example, coincides with the one line 150 when viewed from the Z direction (see FIG. 8). The second line 152 extends along the other of the pair of adjacent lines 150 and, for example, coincides with the other line 150 when viewed from the Z direction (see FIG. 8).

[0103] In the second processing example, as shown in FIG. 12A, first, the focusing lens 14 is relatively moved in one direction in the X direction along the first line 151, and multiple focusing points P1 and P2 are relatively moved in one direction in the X direction along the first line 151. In this case, the laser light L is modulated by the spatial light modulator 36 so that the focusing point P1 is located forward of the focusing point P2 in the X direction (forward in the direction of relative movement) and closer to the first surface 100a than the focusing point P2 in the Z direction. This forms the modified region 110 along the first line 151. At this time, the distance measurement unit 17 detects the height of the second surface 100b along the first line 151. 12B, the focusing lens 14 is moved relatively in the other direction in the X direction (opposite to the one direction) along the second line 152, and the focusing point P is moved relatively in the other direction in the X direction along the second line 152. In this case, the laser light L is modulated by the spatial light modulator 36 so that the focusing point P1 is located forward of the focusing point P2 in the X direction and closer to the first surface 100a than the focusing point P2 in the Z direction. This forms the modified region 110 along the second line 152. At this time, the distance measurement unit 17 detects the height of the second surface 100b along the second line 152.

[0104] The height of the second surface 100b is detected in an effective region 104, which is the region inside the bevel portion 103 of the object 100. The modified region 110 is formed in a formation region 105, which is the region of the effective region 104 where the functional element layer 102 is formed.

[0105] The relative movement of the focusing lens 14 and the focusing point P in the direction parallel to the first line 151 and the second line 152 is relative movement with respect to the object 100, and in the laser processing apparatus 1, this is achieved by the movement mechanism 5 moving the support part 7 in the X direction (see FIG. 1 ). The relative movement of the focusing lens 14 and the focusing point P in the direction perpendicular to the first line 151 and the second line 152 is relative movement with respect to the object 100, and in the laser processing apparatus 1, this is achieved by the movement mechanism 6 moving each of the laser processing heads 10A, 10B in the Y direction and the Z direction (see FIG. 1 ).

[0106] The third and fourth processing examples implemented in the second processing example will be described below. The third and fourth processing examples are implemented by the control unit 9 controlling each part of the laser processing apparatus 1 (at least the light source 81, the attenuator 32, the spatial light modulator 36, and the distance measurement unit 17). Here, the case where the laser light L oscillated by the light source 81 is emitted from the laser processing head 10A will be described, but the same applies to the case where the laser light L oscillated by the light source 82 is emitted from the laser processing head 10B. [Third Processing Example]

[0107] 13 , the control unit 9 executes a first movement process MP1. The first movement process MP1 is a process of relatively moving the condenser lens 14 in one direction in the X direction along the first line 151. The control unit 9 executes a first detection process DP1 and a first oscillation process OP1 during the first movement process MP1. The first detection process DP1 is a process of detecting the height of the second surface 100b along the first line 151. The first oscillation process OP1 is a process of causing the light source 81 to oscillate laser light L so that the focal point P moves relatively in one direction in the X direction along the first line 151.

[0108] The positions are as follows: The first movement process MP1 is performed from a position on one side outside the object 100 in the X direction to a position on the other side outside the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the first movement process MP1 based on preset coordinate information. The first detection process DP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the effective area 104 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first detection process DP1 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the first detection process DP1 based on changes in the light intensity detected by the distance measurement unit 17. The first oscillation process OP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the formation area 105 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first oscillation process OP1 based on preset coordinate information.

[0109] The timing is as follows: The control unit 9 starts the first movement process MP1 by outputting an operation start signal to the movement mechanism 5 at t1, and ends the first movement process MP1 by outputting an operation end signal to the movement mechanism 5 at t6. The control unit 9 starts the first detection process DP1 by outputting an operation start signal to the distance measurement unit 17 at t2, and ends the first detection process DP1 by outputting an operation end signal to the distance measurement unit 17 at t5. The control unit 9 starts the first oscillation process OP1 by outputting an operation start signal to the light source 81 at t3, and ends the first oscillation process OP1 by outputting an operation end signal to the light source 81 at t4. Note that t1, t2, t3, t4, t5, and t6 are arranged chronologically in this order.

[0110] The above-mentioned t4 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal that switches the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal that switches the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0111] The control unit 9 executes a second movement process MP2 after a predetermined time has elapsed since the first movement process MP1. The second movement process MP2 is a process of relatively moving the condenser lens 14 in the other direction in the X direction along the second line 152. The control unit 9 executes a second detection process DP2 and a second oscillation process OP2 during the second movement process MP2. The second detection process DP2 is a process of detecting the height of the second surface 100b along the second line 152. The second oscillation process OP2 is a process of causing the light source 81 to oscillate the laser light L so that the focal point P moves relatively along the second line 152 in the other direction in the X direction.

[0112] The positions are as follows: The second movement process MP2 is performed from a position on the other side of the object 100 in the X direction to a position on one side of the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the second movement process MP2 based on preset coordinate information. The second detection process DP2 is performed between a pair of intersections where the second line 152 and the outer edge of the effective area 104 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second detection process DP2 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the second detection process DP2 based on a change in the light amount detected by the distance measurement unit 17. The second oscillation process OP2 is performed between a pair of intersections where the second line 152 and the outer edge of the formation area 105 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second oscillation process OP2 based on preset coordinate information.

[0113] The timing is as follows: The control unit 9 starts the second movement process MP2 by outputting an operation start signal to the movement mechanism 5 at t7, and ends the second movement process MP2 by outputting an operation end signal to the movement mechanism 5 at t12. The control unit 9 starts the second detection process DP2 by outputting an operation start signal to the distance measurement unit 17 at t8, and ends the second detection process DP2 by outputting an operation end signal to the distance measurement unit 17 at t11. The control unit 9 starts the second oscillation process OP2 by outputting an operation start signal to the light source 81 at t9, and ends the second oscillation process OP2 by outputting an operation end signal to the light source 81 at t10. Note that t7, t8, t9, t10, t11, and t12 are arranged chronologically in this order.

[0114] The above-mentioned t10 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal that switches the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal that switches the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0115] The control unit 9 executes a stop process SP between the first movement process MP1 and the second movement process MP2 (i.e., between t6 and t7). The stop process SP is a process for stopping the relative movement of the condenser lens 14 in the directions along the first line 151 and the second line 152. The control unit 9 executes a third movement process MP3 during the stop process SP. The third movement process MP3 is a process for relatively moving the condenser lens 14 from the end position of the first movement process MP1 to the start position of the second movement process MP2. The control unit 9 executes a process for relatively moving the condenser lens 14 from a position along the first line 151 to a position along the second line 152 when the condenser lens 14 is located outside the target object 100 when viewed from the optical axis direction of the condenser lens 14. In addition, the control unit 9 determines whether the focusing lens 14 is located inside or outside the object 100 when viewed from the optical axis direction of the focusing lens 14 based on pre-set coordinate information or based on changes in the amount of light detected by the distance measurement unit 17.

[0116] As described above, the end position of the first movement process MP1 is a position along the first line 151 on the other side of the object 100 outside in the X direction. The start position of the second movement process MP2 is a position along the second line 152 on the other side of the object 100 outside in the X direction. In other words, the end position of the first movement process MP1 and the start position of the second movement process MP2 differ in the Y direction. The control unit 9 starts the third movement process MP3 by outputting an operation start signal for the movement mechanism 6 after t6 (i.e., simultaneously with or thereafter) when the operation end signal for the movement mechanism 5 is output, and ends the third movement process MP3 by outputting an operation end signal for the movement mechanism 6 before t7 (i.e., simultaneously with or before) when the operation start signal for the movement mechanism 5 is output.

[0117] The control unit 9 executes a switching process CP between the first oscillation process OP1 and the second oscillation process OP2 (i.e., between t4 and t9). The switching process CP includes a modulation pattern switching process. As described above, the modulation pattern switching process is a process for switching the modulation pattern displayed by the spatial light modulator 36. As an example, the modulation pattern switching process is executed so that the positional relationship between the condensing point P1 and the condensing point P2 in the X direction is swapped between the first oscillation process OP1 and the second oscillation process OP2.

[0118] During the first movement process MP1, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 (i.e., between t4 and t6). In the third processing example, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 and before completing the first detection process DP1 (i.e., between t4 and t5). That is, during the first movement process MP1, the control unit 9 starts the switching process CP when the condenser lens 14 is positioned within the object 100 when viewed from the optical axis direction of the condenser lens 14. The control unit 9 starts the switching process CP by outputting a modulation pattern switching signal to the spatial light modulator 36, triggered, for example, by the timing when the control unit 9 outputs an operation end signal to the light source 81. Note that the switching process CP ends when the spatial light modulator 36 has completed switching the modulation pattern displayed on the liquid crystal layer 366; this does not mean that the control unit 9 outputs an end instruction signal to the spatial light modulator 36. The control unit 9 adjusts the timing of each process (especially t6 and t7) based on the longest time required to switch the irradiation conditions of the laser light L so that the switching process CP is completed at least before the second oscillation process OP2.

[0119] In the first movement process MP1 described above, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the first line 151 before starting the first oscillation process OP1 and the first detection process DP1, and after ending the first oscillation process OP1 and the first detection process DP1, starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the first line 151. Also, in the second movement process MP2 described above, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the second line 152 before starting the second oscillation process OP2 and the second detection process DP2, and starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the second line 152 after ending the second oscillation process OP2 and the second detection process DP2. [Fourth Processing Example]

[0120] 14 , the control unit 9 executes a first movement process MP1. The first movement process MP1 is a process of relatively moving the condenser lens 14 in one direction in the X direction along the first line 151. The control unit 9 executes a first detection process DP1 and a first oscillation process OP1 during the first movement process MP1. The first detection process DP1 is a process of detecting the height of the second surface 100b along the first line 151. The first oscillation process OP1 is a process of causing the light source 81 to oscillate laser light L so that the focal point P moves relatively in one direction in the X direction along the first line 151.

[0121] The positions are as follows: The first movement process MP1 is performed from a position on one side outside the object 100 in the X direction to a position on the other side outside the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the first movement process MP1 based on preset coordinate information. The first detection process DP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the effective area 104 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first detection process DP1 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the first detection process DP1 based on changes in the light intensity detected by the distance measurement unit 17. The first oscillation process OP1 is performed between a pair of intersections where the first line 151 intersects with the outer edge of the formation area 105 when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the first oscillation process OP1 based on preset coordinate information.

[0122] The timing is as follows: The control unit 9 starts the first movement process MP1 by outputting an operation start signal to the movement mechanism 5 at t21, and ends the first movement process MP1 by outputting an operation end signal to the movement mechanism 5 at t26. The control unit 9 starts the first detection process DP1 by outputting an operation start signal to the distance measurement unit 17 at t22, and ends the first detection process DP1 by outputting an operation end signal to the distance measurement unit 17 at t25. The control unit 9 starts the first oscillation process OP1 by outputting an operation start signal to the light source 81 at t23, and ends the first oscillation process OP1 by outputting an operation end signal to the light source 81 at t24. Note that t21, t22, t23, t24, t25, and t26 are arranged chronologically in this order.

[0123] The above-mentioned t24 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal that switches the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal that switches the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0124] Following the first movement process MP1, the control unit 9 executes a second movement process MP2. The second movement process MP2 is a process of relatively moving the condenser lens 14 in the other direction in the X direction along the second line 152. During the second movement process MP2, the control unit 9 executes a second detection process DP2 and a second oscillation process OP2. The second detection process DP2 is a process of detecting the height of the second surface 100b along the second line 152. The second oscillation process OP2 is a process of causing the light source 81 to oscillate laser light L so that the focal point P moves relatively along the second line 152 in the other direction in the X direction.

[0125] The positions are as follows: The second movement process MP2 is performed from a position on the other side of the object 100 in the X direction to a position on one side of the object 100 in the X direction. The control unit 9 determines the positions of the start point and end point of the second movement process MP2 based on preset coordinate information. The second detection process DP2 is performed between a pair of intersections where the second line 152 and the outer edge of the effective area 104 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second detection process DP2 based on preset coordinate information. The control unit 9 may also determine the positions of the start point and end point of the second detection process DP2 based on a change in the light amount detected by the distance measurement unit 17. The second oscillation process OP2 is performed between a pair of intersections where the second line 152 and the outer edge of the formation area 105 intersect when viewed from the Z direction. The control unit 9 determines the positions of the start point and end point of the second oscillation process OP2 based on preset coordinate information.

[0126] The timing is as follows: The control unit 9 starts the second movement process MP2 by outputting an operation start signal to the movement mechanism 5 at t26, and ends the second movement process MP2 by outputting an operation end signal to the movement mechanism 5 at t31. The control unit 9 starts the second detection process DP2 by outputting an operation start signal to the distance measurement unit 17 at t27, and ends the second detection process DP2 by outputting an operation end signal to the distance measurement unit 17 at t30. The control unit 9 starts the second oscillation process OP2 by outputting an operation start signal to the light source 81 at t28, and ends the second oscillation process OP2 by outputting an operation end signal to the light source 81 at t29. Note that t26, t27, t28, t29, t30, and t31 are arranged chronologically in this order.

[0127] The above-mentioned t29 is the timing when the control unit 9 outputs an operation end signal to the light source 81, and a small amount of the modified region 110 may be formed after this timing. Furthermore, if the laser light L is pulsed by the light source 81, a small amount of the pulse train may remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal to switch the laser oscillation in the light source 81 from ON to OFF, or, if the laser light L is pulsed by the light source 81, may be a signal to switch the laser oscillation in the light source 81 from pulsed oscillation to continuous oscillation.

[0128] The control unit 9 executes a third movement process MP3 between the first detection process DP1 and the second detection process DP2. The third movement process MP3 is a process for relatively moving the condenser lens 14 from a position along the first line 151 to a position along the second line 152. In the fourth processing example, the "relative movement of the condenser lens 14 in the Y direction" by the third movement process MP3 is performed simultaneously with the "relative movement of the condenser lens 14 to one side in the X direction" by the first movement process MP1 and the "relative movement of the condenser lens 14 to the other side in the X direction" by the second movement process MP2.

[0129] The control unit 9 executes a switching process CP between the first oscillation process OP1 and the second oscillation process OP2 (i.e., between t24 and t28). The switching process CP includes a modulation pattern switching process. As described above, the modulation pattern switching process is a process for switching the modulation pattern displayed by the spatial light modulator 36. As an example, the modulation pattern switching process is executed so that the positional relationship between the condensing point P1 and the condensing point P2 in the X direction is swapped between the first oscillation process OP1 and the second oscillation process OP2.

[0130] During the first movement process MP1, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 (i.e., between t24 and t26). In the fourth processing example, the control unit 9 starts the switching process CP after completing the first oscillation process OP1 and before completing the first detection process DP1 (i.e., between t24 and t25). That is, during the first movement process MP1, the control unit 9 starts the switching process CP when the condenser lens 14 is positioned within the target object 100 when viewed from the optical axis direction of the condenser lens 14. The control unit 9 starts the switching process CP by outputting a modulation pattern switching signal to the spatial light modulator 36, triggered, for example, by the timing when the control unit 9 outputs an operation end signal to the light source 81. Note that the switching process CP ends when the spatial light modulator 36 has completed switching the modulation pattern displayed on the liquid crystal layer 366; this does not mean that the control unit 9 outputs an end instruction signal to the spatial light modulator 36. The control unit 9 adjusts the timing of each process (especially t26) based on the longest time required to switch the irradiation conditions of the laser light L so that the switching process CP is completed at least before the second oscillation process OP2.

[0131] In the above-described first movement process MP1, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the first line 151 before starting the first oscillation process OP1 and the first detection process DP1, and after ending the first oscillation process OP1 and the first detection process DP1, starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the first line 151. Also, in the above-described second movement process MP2, the control unit 9 ends the process of accelerating the relative movement of the focusing lens 14 in the direction along the second line 152 before starting the second oscillation process OP2 and the second detection process DP2, and starts the process of decelerating the relative movement of the focusing lens 14 in the direction along the second line 152 after ending the second oscillation process OP2 and the second detection process DP2. [Operation and Effects]

[0132] In the first, second, third, and fourth process examples, the control unit 9 starts a switching process CP for switching the irradiation conditions of the laser light L after completing a first oscillation process OP1 for causing the light source 81 to oscillate the laser light L during a first movement process MP1 for relatively moving the condenser lens 14 in one direction along the first line 151. As a result, the second oscillation process OP2 for causing the light source 81 to oscillate the laser light L can be started earlier during a second movement process MP2 for relatively moving the condenser lens 14 in the other direction along the second line 152, for example, compared to when the switching process CP is started after the first movement process MP1 is completed. Therefore, the laser processing apparatus 1 can shorten the takt time.

[0133] In the first, second, third, and fourth process examples, the control unit 9 executes a first detection process DP1 during the first movement process MP1 to detect the height of the second surface 100b along the first line 151. After completing the first oscillation process OP1 and the first detection process DP1 as the first movement process MP1, the control unit 9 starts a process to decelerate the relative movement of the condenser lens 14 in the direction along the first line 151. In this way, by starting the deceleration process after completing the first oscillation process OP1, it is possible to further shorten the takt time. On the other hand, starting the deceleration process may cause vibrations. However, by starting the deceleration process after completing the first detection process DP1, it is possible to suppress the occurrence of vibrations during the first detection process DP1, and as a result, it is possible to accurately detect the height of the second surface 100b.

[0134] In the first, second, third, and fourth processing examples, the control unit 9 starts the switching process CP during the first movement process MP1 when the condenser lens 14 is located inside the object 100 as viewed from the optical axis direction of the condenser lens 14. This makes it possible to shorten the takt time compared to waiting to start the switching process CP until the condenser lens 14 is located outside the object 100 as viewed from the optical axis direction of the condenser lens 14.

[0135] In the first and third processing examples, the control unit 9 executes a stop process SP between the first movement process MP1 and the second movement process MP2 to stop the relative movement of the condenser lens 14 in the directions along the first line 151 and the second line 152. By adjusting the time of the stop process SP, the switching process CP for switching the irradiation conditions of the laser light L can be reliably completed, thereby suppressing the occurrence of processing defects.

[0136] In the first and third processing examples, the control unit 9 executes a third movement process MP3 during the stop process SP, which relatively moves the condenser lens 14 from the end position of the first movement process MP1 to the start position of the second movement process MP2. This allows the condenser lens 14 to be reliably positioned at the start position of the second movement process MP2, thereby suppressing the occurrence of processing defects.

[0137] In the first and third processing examples, when the condenser lens 14 is located outside the target object 100 as viewed from the optical axis direction of the condenser lens 14, the control unit 9 executes a process of relatively moving the condenser lens 14 from a position along the first line 151 to a position along the second line 152. This allows the condenser lens 14 to be reliably positioned at the start position of the second movement process MP2, thereby suppressing the occurrence of processing defects. [Modification]

[0138] The present disclosure is not limited to the above-described embodiments. For example, in the second and fourth process examples, similar to the first and third process examples, the switching process CP may be completed before the second movement process MP2. That is, the control unit 9 may execute the switching process CP between the first oscillation process OP1 and the second movement process MP2. This ensures that the switching process CP for switching the irradiation conditions of the laser light L is completed before the second oscillation process OP2 is started, thereby reducing the takt time and suppressing the occurrence of processing defects.

[0139] In the first, second, third, and fourth processing examples, the switching process CP may include at least one of output switching process and modulation pattern switching process.

[0140] The surface of the object 100 whose height is detected by the distance measuring unit 17 is not limited to the surface of the object 100 on the incident side of the laser light L, but may be another surface of the object 100. This is because the distance measuring unit 17 spatially separates the light reflected by each surface.

[0141] The control unit 9 stores multiple conditions for the laser light L, each of which includes, for example, "a pulse width value, a repetition frequency value, and an output value," and may perform a switching process to switch from "the conditions set for the first oscillation process OP1" to "the conditions set for the second oscillation process OP2."

[0142] 1...laser processing device, 7...support part, 9...control part, 14...condensing lens, 17...distance measuring part (detection part), 32...attenuator (adjustment part), 36...spatial light modulator, 81...light source, 100...target object, 110...modified area, 151...first line, 152...second line, L...laser light, P, P1, P2...focus point, CP...switching process, DP1...first detection process (detection process), MP1...first movement process, MP2...second movement process, MP3...third movement process, OP1...first oscillation process, OP2...second oscillation process, SP...stop process.

Claims

1. A laser beam irradiation device comprising: a support section for supporting an object; a light source for emitting laser light; an adjustment section for adjusting the output of the laser light oscillated by the light source; a spatial light modulator for modulating the laser light oscillated by the light source; a focusing lens for focusing the laser light whose output has been adjusted by the adjustment section and whose modulated by the spatial light modulator; and a control section for controlling at least the light source, the adjustment section, and the spatial light modulator, wherein the control section, when forming modified regions along each of a first line and a second line set on the object by positioning a focusing point of the laser light inside the object, performs a first movement process for relatively moving the focusing lens in one direction along the first line; a first oscillation process for causing the light source to oscillate the laser light so that the focusing point moves relatively in the one direction along the first line during the first movement process; and a second movement process for relatively moving the focusing lens in the other direction along the second line. a second oscillation process for causing the light source to oscillate the laser light so that the focal point moves relatively in the other direction along the second line during the second movement process; and a switching process including at least one of a process of switching the setting value of the output adjusted by the adjustment unit between the first oscillation process and the second oscillation process, and a process of switching the modulation pattern displayed by the spatial light modulator between the first oscillation process and the second oscillation process, wherein the control unit starts the switching process after finishing the first oscillation process during the first movement process.

2. The laser processing apparatus of claim 1, wherein the control unit further executes a stop process between the first movement process and the second movement process to stop the relative movement of the focusing lens in directions along each of the first line and the second line.

3. The laser processing apparatus according to claim 2, wherein the control unit further executes a third movement process during the stop process to relatively move the focusing lens from the end position of the first movement process to the start position of the second movement process.

4. A laser processing device according to any one of claims 1 to 3, wherein the control unit executes the switching process between the first oscillation process and the second movement process.

5. A laser processing apparatus as described in any one of claims 1 to 4, further comprising a detection unit that detects the height of the surface of the target object, wherein the control unit further executes a detection process to detect the height along the first line during the first movement process, and wherein the control unit, as the first movement process, starts a process of decelerating the relative movement of the focusing lens in the direction along the first line after completing the first oscillation process and the detection process.

6. A laser processing device as described in any one of claims 1 to 5, wherein the control unit initiates the switching process when the focusing lens is positioned within the target object when viewed from the optical axis direction of the focusing lens during the first movement process.

7. A laser processing apparatus as described in any one of claims 1 to 6, wherein the control unit executes a process of relatively moving the focusing lens from a position along the first line to a position along the second line when the focusing lens is located outside the target object when viewed from the optical axis direction of the focusing lens.

Images