Laser processing device

Abstract

To provide a laser processing device capable of shortening a tact time.SOLUTION: A laser processing device includes a control unit. The control unit executes: a first movement process MP1 for relatively moving a condenser lens in one direction along a first line; a first oscillation process OP1 for causing a light source to emit laser light during the first movement process MP1; a second movement process MP2 for relatively moving the condenser lens in a different direction along a second line; a second oscillation process OP2 for causing the light source to emit laser light during the second movement process MP2; and, between the first oscillation process OP1 and the second oscillation process OP2, a switching process CP for switching irradiation conditions of the laser light. The control unit starts the switching process CP after completing the first oscillation process OP1 during the first movement process MP1.SELECTED DRAWING: Figure 10

Description

Technical Field

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

Background Art

[0002] In order to cut a wafer into a plurality of chips, a laser processing apparatus is known that moves the condensing point of laser light along each of a plurality of lines set in a grid pattern with respect to an object, and forms a modified region inside the object along each of the plurality of lines (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the laser light apparatus as described above, for example, when relatively moving the condenser lens from one line to the other line between adjacent lines, the irradiation conditions of the laser light may be switched. In such a case, it is important in shortening the tact time how efficiently the condenser lens can be relatively moved from one line to the other line while securing the time for switching the irradiation conditions of the laser light.

[0005] Therefore, an object of the present invention is to provide a laser processing apparatus capable of shortening the tact time.

Means for Solving the Problems

[0006] The laser processing apparatus of the present invention includes: [1] a support unit that supports an object, a light source that oscillates laser light, an adjustment unit that adjusts the 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 condenser lens that condenses the laser light whose output has been adjusted by the adjustment unit and that has been 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. When forming a modified region along each of a first line and a second line set in the object by positioning a condensing point of the laser light inside the object, the control unit performs a first movement process of relatively moving the condenser lens in one direction along the first line, a first oscillation process of oscillating the laser light from the light source so that the condensing point relatively moves in the one direction along the first line during the first movement process, a second movement process of relatively moving the condenser lens in the other direction along the second line, a second oscillation process of oscillating the laser light from the light source so that the condensing point relatively moves in the other direction along the second line during the second movement process, a switching process including at least one of a process of switching a set value of the output adjusted by the adjustment unit and a process of switching a modulation pattern displayed by the spatial light modulator between the first oscillation process and the second oscillation process, and the control unit starts the switching process after ending the first oscillation process during the first movement process.

[0007] In the laser processing apparatus described in [1] above, during the first movement process in which the control unit relatively moves the condenser lens in one direction along the first line, after the first oscillation process of oscillating the laser light to the light source is completed, a switching process of switching the irradiation conditions of the laser light is started. Thereby, for example, compared with the case where the switching process is started after the first movement process is completed, during the second movement process in which the condenser lens is relatively moved in the other direction along the second line, the second oscillation process of oscillating the laser light to the light source can be started earlier. Therefore, according to the laser processing apparatus described in [1] above, the tact time can be shortened.

[0008] The laser processing apparatus of the present invention may be the laser processing apparatus described in [1] above, wherein "the control unit further executes a stop process of 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 apparatus described in [2] above, by adjusting the time of the stop process, the switching process of switching the irradiation conditions of the laser light can be surely completed, so that the occurrence of processing defects can be suppressed.

[0009] The laser processing apparatus of the present invention may be the laser processing apparatus described in [2] above, wherein "the control unit further executes a third movement process of relatively moving the condenser lens from the end position of the first movement process to the start position of the second movement process during the stop process". According to the laser processing apparatus described in [3] above, since the condenser lens can be surely positioned at the start position of the second movement process, the occurrence of processing defects can be suppressed.

[0010] The laser processing apparatus of the present invention may be the one described in any one of [1] to [3] above, where "[4] the control unit executes the switching process between the first oscillation process and the second movement process". According to the laser processing apparatus described in [4], before starting the second oscillation process, the switching process for switching the irradiation conditions of the laser light can be surely completed. Therefore, it is possible to suppress the occurrence of processing defects while shortening the tact time.

[0011] The laser processing apparatus of the present invention may be the one described in any one of [1] to [4] above, where "[5] it further includes a detection unit for detecting the height of the surface of the object, and 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, as the first movement process, starts a deceleration process in the relative movement of the condenser lens in the direction along the first line after finishing the first oscillation process and the detection process". According to the laser processing apparatus described in [5], by starting the deceleration process after finishing the first oscillation process, further shortening of the tact time can be achieved. On the other hand, although vibration may occur when starting the deceleration process, by starting the deceleration process after finishing the detection process, the occurrence of vibration during the detection process can be suppressed, and as a result, the height of the surface of the object can be accurately detected.

[0012] The laser processing apparatus of the present invention may be the one described in any one of [1] to [5] above, where "[6] the control unit starts the switching process when the condenser lens is located within the object when viewed from the optical axis direction of the condenser lens during the first movement process". According to the laser processing apparatus described in [6], compared with the case of waiting to start the switching process until the condenser lens is located outside the object when viewed from the optical axis direction of the condenser lens, shortening of the tact time can be achieved.

[0013] The laser processing apparatus of the present invention may be "[7] the laser processing apparatus according to any one of [1] to [6] above, wherein the control unit executes a process of relatively moving the condenser lens from a position along the first line to a position along the second line when the condenser lens is located outside the object when viewed from the optical axis direction of the condenser lens." According to the laser processing apparatus described in [7], since the condenser lens can be surely positioned at the start position of the second movement process, the occurrence of processing defects can be suppressed.

Effect of the Invention

[0014] According to the present invention, it is possible to provide a laser processing apparatus capable of shortening the tact time.

Brief Description of the Drawings

[0015]

Figure 1

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Figure 14

Embodiment for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted. [Configuration of Laser Processing Apparatus]

[0017] As shown in FIG. 1, the laser processing apparatus 1 includes a plurality of moving mechanisms 5 and 6, a support portion 7, a pair of laser processing heads 10A and 10B, a light source unit 8, and a control unit 9. Hereinafter, the first direction is the Z direction, the second direction perpendicular to the first direction is the X direction, and the third direction perpendicular to both the first direction and the second direction is the Y direction. In the present embodiment, the Z direction is the vertical direction, and the X direction and the Y direction are the horizontal directions.

[0018] The moving mechanism 5 has a fixed portion 51, a moving portion 53, and a mounting portion 55. The fixed portion 51 is attached to the apparatus frame 1a. The moving portion 53 is attached to a rail provided on the fixed portion 51 and can move along the Y direction. The mounting portion 55 is attached to a rail provided on the moving portion 53 and can move along the X direction.

[0019] The moving 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 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 part 7 is attached to a rotating shaft provided on the mounting part 55 of the moving mechanism 5 and can rotate about an axis parallel to the Z direction as the center line. The support part 7 supports the object 100. In this embodiment, the object 100 is a wafer.

[0021] As shown in FIGS. 1 and 2, the laser processing head 10A is attached to the mounting part 65 of the moving mechanism 6. The laser processing head 10A irradiates the object 100 supported by the support part 7 with the laser beam L in a state of facing the support part 7 in the Z direction. The laser processing head 10B is attached to the mounting part 66 of the moving mechanism 6. The laser processing head 10B irradiates the object 100 supported by the support part 7 with the laser beam L in a state of facing the support part 7 in the Z direction.

[0022] As shown in FIG. 1, the light source unit 8 has a pair of light sources 81 and 82. The pair of light sources 81 and 82 are attached to the device frame 1a. Each of the pair of light sources 81 and 82 oscillates the laser beam L. The laser beam L emitted from the emission part 81a of the light source 81 is guided to the laser processing head 10A by the optical fiber 2. The laser beam L emitted from the emission part 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 (a plurality of moving mechanisms 5, 6, a pair of laser processing heads 10A, 10B, the light source unit 8, etc.). The control unit 9 is configured as a computer device including a processor, a memory, a storage, a communication device, etc. In the control unit 9, software (program) read into the memory or the like is executed by the processor, and the reading and writing of data in the memory and the storage, and the communication by the communication device are controlled by the processor. Thereby, 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 receives input of instructions by an operator.

[0024] The laser processing apparatus 1 configured as described above can be used for various applications such as dicing processing for dividing a wafer, slicing processing for thinning a wafer, trimming processing for removing an outer peripheral portion from a wafer, and the like. Here, an example of processing by the laser processing apparatus 1 will be described. An example of the processing is an example of forming a modified region inside the object 100 along each of a plurality of lines set in a grid pattern in order to cut the object 100, which is a wafer, into a plurality of chips (that is, an example of the first half of dicing processing).

[0025] First, the moving mechanism 5 moves the support unit 7 along the X direction and the Y direction respectively so that the support unit 7 supporting the object 100 faces the pair of laser processing heads 10A, 10B in the Z direction. Subsequently, the moving mechanism 5 rotates the support unit 7 about an axis parallel to the Z direction as a center line so that a plurality of lines extending in one direction in the object 100 are along the X direction.

[0026] Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the condensing point of the laser beam L emitted from the laser processing head 10A (hereinafter referred to as "the laser beam L of the laser processing head 10A") is located on a line extending in one direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction so that the condensing point of the laser beam L emitted from the laser processing head 10B (hereinafter referred to as "the laser beam L of the laser processing head 10B") is located on another line extending in one direction. Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the condensing point of the laser beam L of the laser processing head 10A is located inside the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the condensing point of the laser beam L of the laser processing head 10B is located inside the object 100.

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

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

[0029] Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the condensing point of the laser beam L of the laser processing head 10A is located on one line extending in the other direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction so that the condensing point of the laser beam L of the laser processing head 10B is located on another line extending in the other direction. Subsequently, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the condensing point of the laser beam L of the laser processing head 10A is located inside the object 100. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the condensing point of the laser beam L of the laser processing head 10B is located inside the object 100.

[0030] Subsequently, the light source 81 emits the laser beam L and the laser processing head 10A irradiates the object 100 with the laser beam L, and at the same time, the light source 82 emits the laser beam L and the laser processing head 10B irradiates the object 100 with the laser beam L. At the same time, the moving mechanism 5 moves the support portion 7 along the X direction so that the condensing point of the laser beam L of the laser processing head 10A moves relatively along one line extending in the other direction and the condensing point of the laser beam 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 a modified region inside the object 100 along each of a plurality of lines extending in the other direction orthogonal to one direction in the object 100.

[0031] In an example of the above processing, each of the pair of light sources 81 and 82 emits a laser beam L having transmissivity with respect to the object 100, for example, by a pulse oscillation method. When such a laser beam L is condensed inside the object 100, the laser beam L is particularly absorbed at the portion corresponding to the condensing point of the laser beam L, and a modified region is formed inside the object 100. The modified region is a region where the density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding unmodified region. Examples of the modified region include a melting treatment region, a crack region, an insulation breakdown region, a refractive index change region, and the like.

[0032] The laser beam L emitted by the pulse oscillation method is irradiated onto the object 100. When the condensing point of the laser beam L is relatively moved along the line set on the object 100, a plurality of modified spots are formed so as to line up in a row along the line. One modified spot is formed by the irradiation of one pulse of the laser beam L. A row of modified regions is a collection of a plurality of 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 movement speed of the condensing point of the laser beam L with respect to the object 100 and the repetition frequency of the laser beam L. [Configuration of 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 adjustment 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. Note that 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 portion 21 is located on the side opposite to the fixed portion 61 of the moving mechanism 6, and the second wall portion 22 is located on the fixed portion 61 side. The third wall portion 23 is located on the mounting portion 65 side of the moving mechanism 6, and the fourth wall portion 24 is located on the side opposite to the mounting portion 65 and on the laser processing head 10B side. The fifth wall portion 25 is located on the side opposite to the support portion 7, and the sixth wall portion 26 is located on the support portion 7 side.

[0037] The housing 11 is configured such that the housing 11 is attached to the attachment portion 65 with the third wall portion 23 disposed on the attachment portion 65 side of the moving mechanism 6. Specifically, it is as follows. The attachment portion 65 has a base plate 65a and an attachment plate 65b. The base plate 65a is attached to a rail provided on the moving portion 63. The attachment plate 65b is erected at the end portion of the base plate 65a on the laser processing head 10B side. The housing 11 is attached to the attachment portion 65 by screwing a bolt 28 to the attachment plate 65b via a pedestal 27 with the third wall portion 23 in contact with the attachment plate 65b. The pedestal 27 is provided on each of the first wall portion 21 and the second wall portion 22. The housing 11 is detachable from the attachment portion 65.

[0038] The incident portion 12 is disposed on the fifth wall portion 25. The incident portion 12 allows the laser beam L to enter the housing 11. The incident portion 12 is offset toward the first wall portion 21 in the X direction and is offset toward the fourth wall portion 24 in the Y direction. That is, 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 emission end portion 2a of the optical fiber 2 is connected to the incident portion 12. Specifically, the incident portion 12 is a portion including a hole 25a formed in the fifth wall portion 25. An attachment portion 25b is provided on the fifth wall portion 25. The main body portion 2b of the emission end portion 2a is attached to the attachment portion 25b by bolts or the like. In this state, the tip portion 2c of the emission end portion 2a passes through the hole 25a. Thereby, the emission end portion 2a of the optical fiber 2 is 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, in the emission end portion 2a, an isolator for suppressing backward light is disposed in the main body portion 2b, and a collimator lens for collimating the laser beam L is disposed in the tip portion 2c. Note that the incident portion 12 may be a connector or the like configured to be connectable to the emission end portion 2a of the optical fiber 2.

[0040] The laser beam adjustment unit 13 is disposed in the housing 11. The laser beam adjustment unit 13 adjusts the laser beam L incident from the incident portion 12. The laser beam adjustment unit 13 is disposed on the fourth wall portion 24 side with respect to the partition wall portion 29 in the housing 11. The laser beam adjustment unit 13 is attached to the partition wall portion 29. The partition wall portion 29 is provided in the housing 11 and partitions the region in the housing 11 into a region on the third wall portion 23 side and a region on the fourth wall portion 24 side. The partition wall portion 29 is configured as a part of the housing 11. Each component included in the laser beam adjustment unit 13 is attached to the partition wall portion 29 on the fourth wall portion 24 side. The partition wall portion 29 functions as an optical base that supports each component included in 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 while passing through a hole 26a (see FIG. 5) formed in the sixth wall portion 26. The condensing lens 14 condenses the laser beam L adjusted by the laser beam adjusting unit 13 and emits it outside the housing 11. The condensing lens 14 is offset toward the second wall portion 22 in the X direction and toward the fourth wall portion 24 in the Y direction. That is, 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 reflection unit 31, an attenuator (adjusting unit) 32, and a reflection unit 33. The reflection unit 31, the attenuator 32, and the reflection unit 33 are disposed on a first straight line SL1 extending along the X direction. The reflection unit 31 faces the incident unit 12 in the Z direction. That is, the reflection unit 31 faces the emission end portion 2a of the optical fiber 2 in the Z direction. The reflection unit 31 reflects the laser beam L incident from the incident unit 12 toward the second wall portion 22. The attenuator 32 adjusts the output of the laser beam L reflected by the reflection unit 31. That is, the attenuator 32 adjusts the output of the laser beam L oscillated by the light source 81. The reflection unit 33 reflects the laser beam L whose output has been adjusted by the attenuator 32 toward the sixth wall portion 26. Each of the reflection units 31 and 33 is, for example, a mirror or a prism.

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

[0044] The laser light adjustment 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 light L reflected by the reflection unit 35. That is, the spatial light modulator 36 modulates the laser light L oscillated by the light source 81. The spatial light modulator 36 is a reflective spatial light modulator, and reflects the laser light L toward the sixth wall portion 26 side while modulating it. The spatial light modulator 36 is, for example, an LCOS (Liquid Crystal on Silicon)-SLM (Spatial Light Modulator). The imaging optical system 37 constitutes a bilateral telecentric optical system in which the reflection surface 36a of the spatial light modulator 36 and the entrance pupil surface 14a of the condenser lens 14 are in an imaging relationship. The imaging optical system 37 is composed of a plurality of lenses. The condenser lens 14 condenses the laser light L whose output is adjusted by the attenuator 32 and which is modulated by the spatial light modulator 36.

[0045] The first straight line SL1, the second straight line SL2, and the third straight line SL3 are located on the same plane perpendicular to the Y direction. The second straight line SL2 is located on the second wall portion 22 side with respect to the third straight line SL3. In the laser processing head 10A, the laser light L incident into the housing 11 from the incident portion 12 along the Z direction is reflected by the reflection unit 31 and travels on the first straight line SL1. The laser light L traveling on the first straight line SL1 is reflected by the reflection unit 33 and travels on the second straight line SL2. The laser light L traveling on the second straight line SL2 is sequentially reflected by the reflection unit 35 and the spatial light modulator 36 and travels on the third straight line SL3. The laser light L traveling on the third straight line SL3 is emitted from the condenser lens 14 out 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 between the imaging optical system 37 and the condenser lens 14 on the third straight line SL3. That is, the dichroic mirror 15 is disposed between the laser light adjustment unit 13 and the condenser lens 14 within the housing 11. The dichroic mirror 15 is attached to the partition wall portion 29 on the fourth wall portion 24 side. 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 two plate types arranged to have a torsional relationship.

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

[0049] In the present embodiment, the observation light L10 emitted from the observation unit 16 is sequentially reflected by the beam splitter 20 and the dichroic mirror 15, passes through the condenser lens 14, is emitted outside the housing 11, and irradiates the surface of the object 100. The observation light L10 reflected by the surface of the object 100 passes through the condenser lens 14, enters the housing 11, is sequentially reflected by the dichroic mirror 15 and the beam splitter 20, and enters the observation unit 16. Note that the beam splitter 20 is attached to the partition wall portion 29 on the fourth wall portion 24 side.

[0050] The distance measurement unit 17 is disposed inside the housing 11 on the side of the first wall portion 21 with respect to the third straight line SL3. That is, in the X direction, the distance measurement unit 17 is disposed on the side of the first wall portion 21 with respect to the condenser lens 14. The distance measurement unit 17 is attached to the partition wall portion 29 on the side of the fourth wall portion 24. The distance measurement unit 17 irradiates the surface of the object 100 (for example, the surface on the side where the laser light L is incident) with a distance measurement light L20 (for example, laser light) for measuring the distance between the surface of the object 100 and the condenser lens 14, and detects the distance measurement light L20 reflected by the surface of the object 100. Thereby, the distance measurement unit 17 detects the height (position in the Z direction) of the surface of the object 100.

[0051] In the present 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 irradiates 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, enters the housing 11, is reflected by the dichroic mirror 15, passes through the beam splitter 20, and enters 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 each other (at least the respective center wavelengths are shifted from each other).

[0052] The drive unit 18 is attached to the partition wall portion 29 on the side of the fourth wall portion 24. The drive unit 18 moves the condenser lens 14 disposed on the sixth wall portion 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 on the side of the third wall portion 23 with respect to the partition wall portion 29 within the housing 11. That is, the circuit unit 19 is disposed on the side of the third wall portion 23 with respect to the laser light adjustment unit 13, the distance measurement unit 17, and the observation unit 16 within the housing 11. The circuit unit 19 is separated from the partition wall portion 29. The circuit unit 19 is, for example, a plurality of circuit boards. The circuit unit 19 processes the signal output from the distance measurement unit 17 and the signal input to the spatial light modulator 36. The circuit unit 19 controls the drive unit 18 based on the signal output from the distance measurement unit 17. As an example, the circuit unit 19 controls the drive unit 18 such that the distance between the surface of the object 100 and the condenser lens 14 is maintained constant (that is, the distance between the surface of the object 100 and the condensing point of the laser light L is maintained constant).

[0054] Note that notches, holes, etc. (not shown) through which wirings 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 are formed in the partition wall portion 29. Further, the housing 11 is provided with a connector (not shown) to which wirings for electrically connecting the circuit unit 19 and the control unit 9 are connected.

[0055] The laser processing head 10B includes, similarly to the laser processing head 10A, a housing 11, an incident unit 12, a laser light adjustment unit 13, a condenser lens 14, a dichroic mirror 15, an observation unit 16, a distance measurement unit 17, a drive unit 18, and a circuit unit 19. However, as shown in FIG. 2, each component of the laser processing head 10B is arranged so as to have a plane-symmetrical relationship with each component of the laser processing head 10A with respect to a virtual plane passing through the midpoint between the pair of attachment portions 65, 66 and perpendicular to the Y direction.

[0056] For example, the housing 11 of the laser processing head 10A is attached to the attachment portion 65 such that the fourth wall portion 24 is located on the laser processing head 10B side with respect to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side with respect to the fifth wall portion 25. On the other hand, the housing 11 of the laser processing head 10B is attached to the attachment portion 66 such that the fourth wall portion 24 is located on the laser processing head 10A side with respect to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side with respect to the fifth wall portion 25.

[0057] The housing 11 of the laser processing head 10B is configured such that the housing 11 is attached to the attachment portion 66 with the third wall portion 23 disposed 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 an end portion 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 Attenuator]

[0058] As shown in FIG. 6, the attenuator 32 has a λ / 2 wave plate 321 and a polarization beam splitter 322. The λ / 2 wave plate 321 can rotate about the first straight line SL1 as a center line. When the laser beam L is incident with its polarization direction inclined by an angle θ with respect to the optical axis (for example, the fast axis) of the λ / 2 wave plate 321, the λ / 2 wave plate 321 rotates the polarization direction by an angle 2θ about the first straight line SL1 as a center line and emits the laser beam L. When the laser beam L emitted from the λ / 2 wave plate 321 is incident on the polarization beam splitter 322, the P polarization component that coincides with the polarization axis of the polarizing plate 342 is transmitted along the first straight line SL1 as the laser beam L, and the S polarization component is reflected. As an example, the polarization beam splitter 322 is a cube-type optical element having an optical surface 322a inclined by a predetermined angle (for example, the 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, so that the output of the laser beam L emitted from the polarization beam splitter 322 (that is, the P polarization component transmitted through the polarization beam splitter 322) is adjusted. Thus, according to the attenuator 32, by appropriately setting the direction of the optical axis of the λ / 2 wave plate 321, the output of the laser beam L can be adjusted. The control unit 9 controls the above-described rotation mechanism to switch the direction of the optical axis of the λ / 2 wave plate 321, thereby executing a process of switching the set value of the output of the laser beam L adjusted by the attenuator 32 (hereinafter referred to as "output switching process"). [Configuration of Spatial Light Modulator]

[0060] As shown in FIG. 7, the spatial light modulator 36 is configured by laminating a drive circuit layer 362, a pixel electrode layer 363, a reflective film 364, an alignment film 365, a liquid crystal layer 366, an alignment 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 a metal material such as aluminum, for example. 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 on the side of the reflective film 364, and the alignment film 367 is provided on the surface of the liquid crystal layer 366 on the side opposite to the reflective film 364. Each of the alignment films 365 and 367 is formed of a polymer material such as polyimide, for example, and a rubbing treatment is performed, for example, on the contact surface of each of the alignment films 365 and 367 with the liquid crystal layer 366. The alignment films 365 and 367 align the liquid crystal molecules 366a contained in the liquid crystal layer 366 in a certain direction.

[0063] The transparent conductive film 368 is provided on the surface of the transparent substrate 369 on the side of the alignment film 367, and faces the pixel electrode layer 363 with the liquid crystal layer 366 and the like interposed therebetween. The transparent substrate 369 is, for example, a glass substrate. The transparent conductive film 368 is formed of a light-transmissive and conductive material such as ITO, for example. 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 the electric field is formed, in the liquid crystal layer 366, the alignment direction of the liquid crystal molecules 216a 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 a state in which the modulation pattern is displayed on the liquid crystal layer 366.

[0065] With the modulation pattern displayed on the liquid crystal layer 366, when the laser beam L is incident on the liquid crystal layer 366 from the outside through the transparent substrate 369 and the transparent conductive film 368, reflected by the reflection film 364, and then emitted from the liquid crystal layer 366 to the outside through the transparent conductive film 368 and the transparent substrate 369, the laser beam L is modulated according to the modulation pattern displayed on the liquid crystal layer 366. Thus, according to the spatial light modulator 36, by appropriately setting the modulation pattern to be displayed on the liquid crystal layer 366, modulation of the laser beam L (for example, modulation of the intensity, amplitude, phase, polarization, etc. of the laser beam L) is possible. The control unit 9 executes a process of switching the modulation pattern displayed by the spatial light modulator 36 (hereinafter referred to as "modulation pattern switching process") by switching the signal input to the drive circuit layer 362. [Configuration of the Object]

[0066] As shown in FIG. 8, the object 100 is a wafer and has a first surface 100a and a second surface 100b opposite to the first surface 100a. The object 100 is configured by laminating a functional element 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. A notch 101c indicating the crystal orientation is provided on the semiconductor substrate 101. Note that an orientation flat may be provided on the semiconductor substrate 101 instead of the notch 101c.

[0068] The functional element layer 102 is provided on the first surface 101a of the semiconductor substrate 101. The functional element layer 102 includes a plurality of functional elements 102a arranged in a matrix along the first surface 101a of the semiconductor substrate 101. Each functional element 1022a is, for example, a light receiving element such as a photodiode, a light emitting element such as a laser diode, a circuit element such as a memory, etc. Each functional element 102a may be three-dimensionally configured by stacking a plurality of layers.

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

[0070] A first processing example in the case where the "object 100 shown in FIG. 8" is processed by the "laser processing apparatus 1 shown in FIG. 1" will be described. As shown in FIGS. 9(a) and 9(b), in the first processing example, with the second surface 100b as the incident surface of the laser beam L, by positioning the focus point P of the laser beam L inside the object 100, the modified regions 110 are formed along each of the first line 151 and the second line 152 set in the object 100. In the first processing example, the first line 151 and the second line 152 are arranged side by side in the Z direction (i.e., the thickness direction of the object 100 which is a wafer). Each of the first line 151 and the second line 152 extends along each line 150 and, for example, coincides with each line 150 when viewed from the Z direction (see FIG. 8).

[0071] In the first processing example, first, as shown in Fig. 9(a), the condensing lens 14 is relatively moved in one direction in the X direction along the first line 151 on the first surface 100a side, and the condensing point P is relatively moved in one direction in the X direction along the first line 151. Thereby, the modified region 110 is formed along the first line 151. At this time, the height of the second surface 100b is detected along the first line 151 by the distance measuring unit 17. Subsequently, as shown in Fig. 9(b), the condensing lens 14 is relatively moved in the other direction (the direction opposite to one direction) in the X direction along the second line 152 on the second surface 100b side, and the condensing point P is relatively moved in the other direction in the X direction along the second line 152. Thereby, the modified region 110 is formed along the second line 152. At this time, the height of the second surface 100b is detected along the second line 152 by the distance measuring unit 17.

[0072] The detection of the height of the second surface 100b is performed in the effective region 104 which is the region inside the bevel portion 103 (that is, the outer peripheral portion of the semiconductor substrate 101) of the object 100. The formation of the modified region 110 is performed in the formation region 105 which is the region where the functional element layer 102 is formed in the effective region 104.

[0073] Note that the relative movement of the condensing lens 14 and the condensing point P in the direction parallel to the first line 151 and the second line 152 is the relative movement with respect to the object 100, and in the laser processing apparatus 1, it is performed by the moving mechanism 5 moving the support portion 7 in the X direction (see Fig. 1). Also, the relative movement of the condensing lens 14 and the condensing point P in the direction perpendicular to the first line 151 and the second line 152 is the relative movement with respect to the object 100, and in the laser processing apparatus 1, it is performed by the moving mechanism 6 moving each of the laser processing heads 10A, 10B in the Y direction and the Z direction respectively (see Fig. 1).

[0074] Hereinafter, a first processing example and a second processing example implemented in the first processing example will be described. The first processing example and the second processing example 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 beam 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 beam L oscillated by the light source 82 is emitted from the laser processing head 10B. [First Processing Example]

[0075] As shown in FIG. 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 oscillating the laser beam L to the light source 81 so that the condensing point P relatively moves in one direction in the X direction along the first line 151.

[0076] The positions are as follows. The first movement process MP1 is carried out 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 grasps the positions of the start point and the end point of the first movement process MP1 based on the preset coordinate information. The first detection process DP1 is carried out between a pair of intersection points where the first line 151 intersects the outer edge of the effective region 104 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first detection process DP1 based on the preset coordinate information. The control unit 9 may also grasp the positions of the start point and the end point of the first detection process DP1 based on the change in the amount of light detected by the distance measurement unit 17. The first oscillation process OP1 is carried out between a pair of intersection points where the first line 151 intersects the outer edge of the formation region 105 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first oscillation process OP1 based on the preset coordinate information.

[0077] In terms of time, it 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 in chronological order in this sequence.

[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 modified region 110 may be slightly formed after this timing. Also, when the laser beam L is pulse-oscillated by the light source 81, a pulse train may slightly remain after this timing. Further, the operation end signal to the light source 81 may be a signal for switching the laser oscillation of the light source 81 from ON to OFF, or when the laser beam L is pulse-oscillated by the light source 81, it may be a signal for switching the laser oscillation of the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[0079] After the first movement process MP1, the control unit 9 executes the second movement process MP2 after a predetermined time has elapsed. 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 the second detection process DP2 and the 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 oscillating the laser beam L from the light source 81 so that the condensing point P relatively moves in the other direction in the X direction along the second line 152.

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

[0081] As for the time sequence, it 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 in chronological order in this sequence.

[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 modified region 110 may be slightly formed after this timing. Also, when the laser beam L is pulsed by the light source 81, a pulse train may slightly remain after this timing. Further, the operation end signal to the light source 81 may be a signal for switching the laser oscillation in the light source 81 from ON to OFF, or when the laser beam L is pulsed by the light source 81, it may be a signal for switching the laser oscillation in the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[0083] The control unit 9 executes a stop process SP between the first movement process MP1 and the second movement process MP2 (that is, 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 respectively. 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 the position along the first line 151 to the position along the second line 152 when the condenser lens 14 is located outside the object 100 when viewed from the optical axis direction of the condenser lens 14. Note that the control unit 9 grasps whether the condenser lens 14 is located inside or outside the object 100 when viewed from the optical axis direction of the condenser lens 14 based on preset coordinate information or based on the change in the amount of light detected by the distance measuring 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. Also, 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. That is, the end position of the first movement process MP1 and the start position of the second movement process MP2 are different 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 (that is, simultaneously with or after that) when an operation end signal to 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 (that is, simultaneously with or before that) when an operation start signal to 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 (that is, 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 of switching the set value of the output of the laser beam L adjusted by the attenuator 32. Also, the modulation pattern switching process is a process of switching the modulation pattern displayed by the spatial light modulator 36. As an example, the output switching process is executed such that the output of the laser beam is lower in the first oscillation process OP1 than in the second oscillation process OP2, and the modulation pattern switching process is executed such that the degree of aberration correction is weakened in the first oscillation process OP1 than in the second oscillation process OP2.

[0086] During the first movement process MP1, after the first oscillation process OP1 ends (i.e., between t4 and t6), the control unit 9 starts the switching process CP. In the first processing example, the control unit 9 starts the switching process CP after the first oscillation process OP1 ends and before the first detection process DP1 ends (i.e., between t4 and t5). That is, during the first movement process MP1, when the condenser lens 14 is located 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. The control unit 9 starts the switching process CP, for example, by outputting an operation start signal to the attenuator 32 and a modulation pattern switching signal to the spatial light modulator 36 using the timing when the control unit 9 outputs an operation end signal to the light source 81 as a trigger. Note that the switching process CP ends when the switching of the optical axis direction of the λ / 2 waveplate 321 is completed in the attenuator 32 and the switching of the modulation pattern displayed on the liquid crystal layer 366 is completed in the spatial light modulator 36, 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 required for switching the modulation pattern displayed on the liquid crystal layer 366 in the spatial light modulator 36 (for example, about 0.2 seconds) is longer than the time required for switching the optical axis direction of the λ / 2 waveplate 321 in the attenuator 32 (for example, about 0.05 to 0.1 seconds). Therefore, the control unit 9 adjusts the timing of each process (especially t6, t7) so that the switching process CP is completed at least before the second oscillation process OP2, based on the longest time required for switching the irradiation conditions of the laser beam L.

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

[0089] As shown in FIG. 11, the control unit 9 executes the 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 the first detection process DP1 and the 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 oscillating the laser beam L to the light source 81 so that the condensing point P relatively moves in one direction in the X direction along the first line 151.

[0090] The positions are as follows. The first movement process MP1 is carried out 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 grasps the positions of the start point and the end point of the first movement process MP1 based on the preset coordinate information. The first detection process DP1 is carried out between a pair of intersection points where the first line 151 intersects the outer edge of the effective region 104 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first detection process DP1 based on the preset coordinate information. The control unit 9 may also grasp the positions of the start point and the end point of the first detection process DP1 based on the change in the amount of light detected by the distance measurement unit 17. The first oscillation process OP1 is carried out between a pair of intersection points where the first line 151 intersects the outer edge of the formation region 105 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first oscillation process OP1 based on the preset coordinate information.

[0091] The time sequence 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, t26 are arranged in chronological order in this sequence.

[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 modified region 110 may be slightly formed after this timing. Further, when the laser beam L is pulse-oscillated by the light source 81, a pulse train may slightly remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal for switching the laser oscillation of the light source 81 from ON to OFF, or when the laser beam L is pulse-oscillated by the light source 81, it may be a signal for switching the laser oscillation of the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[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 oscillating the laser beam L to the light source 81 so that the condensing point P relatively moves in the other direction in the X direction along the second line 152.

[0094] The positions are as follows. The second movement process MP2 is carried out from a position on the other side outside the object 100 in the X direction to a position on one side outside the object 100 in the X direction. The control unit 9 grasps the positions of the start point and the end point of the second movement process MP2 based on the preset coordinate information. The second detection process DP2 is carried out between a pair of intersection points where the second line 152 and the outer edge of the effective region 104 intersect when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the second detection process DP2 based on the preset coordinate information. The control unit 9 may also grasp the positions of the start point and the end point of the second detection process DP2 based on the change in the amount of light detected by the distance measurement unit 17. The second oscillation process OP2 is carried out between a pair of intersection points where the second line 152 and the outer edge of the formation region 105 intersect when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the second oscillation process OP2 based on the 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 in chronological order in this sequence.

[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 modified region 110 may be slightly formed after this timing. Also, when the laser beam L is pulse-oscillated by the light source 81, a pulse train may slightly remain after this timing. Further, the operation end signal to the light source 81 may be a signal for switching the laser oscillation in the light source 81 from ON to OFF, or when the laser beam L is pulse-oscillated by the light source 81, it may be a signal for switching the laser oscillation in the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[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 of 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 carried out 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 (that is, 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 of switching the set value of the output of the laser beam L adjusted by the attenuator 32. Also, the modulation pattern switching process is a process of switching the modulation pattern displayed by the spatial light modulator 36. As an example, the output switching process is executed such that the output of the laser beam is lower during the first oscillation process OP1 than during the second oscillation process OP2, and the modulation pattern switching process is executed such 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, after the first oscillation process OP1 ends (i.e., between t24 and t26), the control unit 9 starts the switching process CP. In the second processing example, after the first oscillation process OP1 ends and before the first detection process DP1 ends (i.e., between t24 and t25), the control unit 9 starts the switching process CP. That is, during the first movement process MP1, when the condenser lens 14 is located within the object 100 as viewed from the optical axis direction of the condenser lens 14, the control unit 9 starts the switching process CP. For example, 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 using the timing when the control unit 9 outputs an operation end signal to the light source 81 as a trigger. Note that the switching process CP ends when the switching of the optical axis direction of the λ / 2 wave plate 321 is completed in the attenuator 32 and the switching of the modulation pattern displayed on the liquid crystal layer 366 is completed in the spatial light modulator 36, 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 required for switching the modulation pattern displayed on the liquid crystal layer 366 in the spatial light modulator 36 (for example, about 0.2 seconds) is longer than the time required for switching the optical axis direction of the λ / 2 wave plate 321 in the attenuator 32 (for example, about 0.05 to 0.1 seconds). Therefore, the control unit 9 adjusts the timing of each process (especially t26) so that the switching process CP is completed at least before the second oscillation process OP2, based on the longest time required for switching the irradiation conditions of the laser beam L.

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

[0102] A second processing example in the case where the "object 100 shown in FIG. 8" is processed by the "laser processing apparatus 1 shown in FIG. 1" will be described. As shown in FIGS. 12(a) and 12(b), in the second processing example, with the second surface 100b as the incident surface of the laser beam L, by positioning the condensing point P of the laser beam L inside the object 100, the modified region 110 is formed along each of the first line 151 and the second line 152 set in the object 100. In the second processing example, the first line 151 and the second line 152 are arranged side by side in the Y direction. The first line 151 extends along one of the 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, first, as shown in Fig. 12(a), the condensing lens 14 is relatively moved in one direction in the X direction along the first line 151, and a plurality of condensing points P1, P2 are relatively moved in one direction in the X direction along the first line 151. In this case, the laser beam L is modulated by the spatial light modulator 36 such that the condensing point P1 is located on the front side (the front side in the relative movement direction) of the condensing point P2 in the X direction and the condensing point P1 is located on the first surface 100a side of the condensing point P2 in the Z direction. Thereby, the modified region 110 is formed along the first line 151. At this time, the height of the second surface 100b is detected along the first line 151 by the distance measuring unit 17. Subsequently, as shown in Fig. 12(b), the condensing lens 14 is relatively moved in the other direction (the direction opposite to one direction) in the X direction along the second line 152, and the condensing point P is relatively moved in the other direction in the X direction along the second line 152. In this case, the laser beam L is modulated by the spatial light modulator 36 such that the condensing point P1 is located on the front side of the condensing point P2 in the X direction and the condensing point P1 is located on the first surface 100a side of the condensing point P2 in the Z direction. Thereby, the modified region 110 is formed along the second line 152. At this time, the height of the second surface 100b is detected along the second line 152 by the distance measuring unit 17.

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

[0105] Note that the relative movement of the condenser lens 14 and the condensing point P in the direction parallel to the first line 151 and the second line 152 is the relative movement with respect to the object 100. In the laser processing apparatus 1, the moving mechanism 5 moves the support portion 7 in the X direction to implement this (see FIG. 1). Further, the relative movement of the condenser lens 14 and the condensing point P in the direction perpendicular to the first line 151 and the second line 152 is the relative movement with respect to the object 100. In the laser processing apparatus 1, the moving mechanism 6 moves each laser processing head 10A, 10B in the respective directions of the Y direction and the Z direction to implement this (see FIG. 1).

[0106] Hereinafter, a third processing example and a fourth processing example implemented in the second processing example will be described. The third processing example and the fourth processing example 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 measuring unit 17). Here, the case where the laser beam 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 beam L oscillated by the light source 82 is emitted from the laser processing head 10B. [Third Processing Example]

[0107] As shown in FIG. 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. During the first movement process MP1, the control unit 9 executes a first 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 oscillating the laser beam L to the light source 81 so that the condensing point P relatively moves in one direction in the X direction along the first line 151.

[0108] The positions are as follows. The first movement process MP1 is carried out 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 grasps the positions of the start point and the end point of the first movement process MP1 based on the preset coordinate information. The first detection process DP1 is carried out between a pair of intersection points where the first line 151 intersects the outer edge of the effective region 104 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first detection process DP1 based on the preset coordinate information. The control unit 9 may also grasp the positions of the start point and the end point of the first detection process DP1 based on the change in the amount of light detected by the distance measurement unit 17. The first oscillation process OP1 is carried out between a pair of intersection points where the first line 151 intersects the outer edge of the formation region 105 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first oscillation process OP1 based on the 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 in chronological order in this sequence.

[0110] The above-mentioned t4 is the timing when the control unit 9 outputs an operation end signal to the light source 81. After this timing, a slightly modified region 110 may be formed. Also, when the laser beam L is pulsed by the light source 81, a slightly remaining pulse train may exist after this timing. Further, the operation end signal to the light source 81 may be a signal for switching the laser oscillation of the light source 81 from ON to OFF, or when the laser beam L is pulsed by the light source 81, it may be a signal for switching the laser oscillation of the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[0111] After the first movement process MP1, the control unit 9 executes the second movement process MP2 after a predetermined time has elapsed. 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 the second detection process DP2 and the 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 oscillating the laser beam L to the light source 81 so that the condensing point P relatively moves in the other direction in the X direction along the second line 152.

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

[0113] The time sequence 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 in chronological order in this sequence.

[0114] The above-mentioned t10 is the timing when the control unit 9 outputs an operation end signal to the light source 81. Even if a slightly modified region 110 is formed after this timing, it is acceptable. Also, when the laser beam L is pulsed by the light source 81, a slightly remaining pulse train may exist after this timing. Further, the operation end signal to the light source 81 may be a signal for switching the laser oscillation in the light source 81 from ON to OFF. Or, when the laser beam L is pulsed by the light source 81, the operation end signal to the light source 81 may be a signal for switching the laser oscillation in the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[0115] The control unit 9 executes a stop process SP between the first movement process MP1 and the second movement process MP2 (that is, 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, respectively. During the stop process SP, the control unit 9 executes a third movement process MP3. 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. When the condenser lens 14 is located outside the object 100 as viewed from the optical axis direction of the condenser lens 14, the control unit 9 executes a process for relatively moving the condenser lens 14 from the position along the first line 151 to the position along the second line 152. Note that the control unit 9 grasps whether the condenser lens 14 is located inside or outside the object 100 as viewed from the optical axis direction of the condenser lens 14 based on preset coordinate information or based on the change 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 outside the object 100 in the X direction. Also, 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. That is, the end position of the first movement process MP1 and the start position of the second movement process MP2 are different 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 (i.e., simultaneously with or after) t6 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 (i.e., simultaneously with or before) t7 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 of switching the modulation pattern displayed by the spatial light modulator 36. As an example, the modulation pattern switching process is executed such that the positional relationship between the light condensing point P1 and the light condensing point P2 in the X direction is interchanged between the first oscillation process OP1 and the second oscillation process OP2.

[0118] During the first movement process MP1, after the first oscillation process OP1 ends (i.e., between t4 and t6), the control unit 9 starts the switching process CP. In the third processing example, after the first oscillation process OP1 ends and before the first detection process DP1 ends (i.e., between t4 and t5), the control unit 9 starts the switching process CP. That is, during the first movement process MP1, when the condenser lens 14 is located 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. The control unit 9 starts the switching process CP, for example, by outputting a modulation pattern switching signal to the spatial light modulator 36 using the timing when the control unit 9 outputs an operation end signal to the light source 81 as a trigger. Note that the switching process CP ends when 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 the spatial light modulator 36. The control unit 9 adjusts the timing of each process (especially t6, t7) so that the switching process CP is completed at least before the second oscillation process OP2, based on the longest time required for switching the irradiation conditions of the laser beam L.

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

[0120] As shown in FIG. 14, the control unit 9 executes the 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 the first detection process DP1 and the 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 oscillating the laser beam L to the light source 81 so that the condensing point P relatively moves in one direction in the X direction along the first line 151.

[0121] Positionally, it is as follows. The first movement process MP1 is carried out 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 grasps the positions of the start point and the end point of the first movement process MP1 based on the preset coordinate information. The first detection process DP1 is carried out between a pair of intersection points where the first line 151 and the outer edge of the effective region 104 intersect when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first detection process DP1 based on the preset coordinate information. The control unit 9 may also grasp the positions of the start point and the end point of the first detection process DP1 based on the change in the amount of light detected by the distance measurement unit 17. The first oscillation process OP1 is carried out between a pair of intersection points where the first line 151 and the outer edge of the formation region 105 intersect when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the first oscillation process OP1 based on the preset coordinate information.

[0122] 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 in chronological order in this sequence.

[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 modified region 110 may be slightly formed after this timing. Also, when the laser beam L is pulsed by the light source 81, a pulse train may slightly remain after this timing. Further, the operation end signal to the light source 81 may be a signal for switching the laser oscillation of the light source 81 from ON to OFF, or when the laser beam L is pulsed by the light source 81, it may be a signal for switching the laser oscillation of the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[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 oscillating the laser beam L to the light source 81 so that the condensing point P relatively moves in the other direction in the X direction along the second line 152.

[0125] The positions are as follows. The second movement process MP2 is carried out from a position on the other side outside the object 100 in the X direction to a position on one side outside the object 100 in the X direction. The control unit 9 grasps the positions of the start point and the end point of the second movement process MP2 based on the preset coordinate information. The second detection process DP2 is carried out between a pair of intersection points where the second line 152 intersects the outer edge of the effective region 104 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the second detection process DP2 based on the preset coordinate information. The control unit 9 may also grasp the positions of the start point and the end point of the second detection process DP2 based on the change in the amount of light detected by the distance measurement unit 17. The second oscillation process OP2 is carried out between a pair of intersection points where the second line 152 intersects the outer edge of the formation region 105 when viewed from the Z direction. The control unit 9 grasps the positions of the start point and the end point of the second oscillation process OP2 based on the 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 in chronological order in this sequence.

[0127] The above-mentioned t29 is the timing when the control unit 9 outputs an operation end signal to the light source 81. Even if a slightly modified region 110 is formed after this timing, it is acceptable. Also, when the laser beam L is pulsed by the light source 81, a pulse train may slightly remain after this timing. Furthermore, the operation end signal to the light source 81 may be a signal that switches the laser oscillation of the light source 81 from ON to OFF. Or, when the laser beam L is pulsed by the light source 81, the operation end signal to the light source 81 may be a signal that switches the laser oscillation of the light source 81 from the pulse oscillation mode to the continuous oscillation mode.

[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 of 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 carried out 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 (that is, 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 of switching the modulation pattern displayed by the spatial light modulator 36. As an example, the modulation pattern switching process is executed such that the positional relationship between the light condensing point P1 and the light condensing point P2 in the X direction is interchanged between the first oscillation process OP1 and the second oscillation process OP2.

[0130] During the first movement process MP1, after the first oscillation process OP1 ends (i.e., between t24 and t26), the control unit 9 starts the switching process CP. In the fourth processing example, after the first oscillation process OP1 ends and before the first detection process DP1 ends (i.e., between t24 and t25), the control unit 9 starts the switching process CP. That is, during the first movement process MP1, when the condenser lens 14 is located 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. For example, the control unit 9 starts the switching process CP by outputting a modulation pattern switching signal to the spatial light modulator 36 using the timing when the control unit 9 outputs an operation end signal to the light source 81 as a trigger. Note that the switching process CP ends when 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 the spatial light modulator 36. The control unit 9 adjusts the timing of each process (especially t26) so that the switching process CP is completed at least before the second oscillation process OP2, based on the longest time required for switching the irradiation conditions of the laser beam L.

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

[0132] In the first processing example, the second processing example, the third processing example, and the fourth processing example, during the first movement process MP1 in which the control unit 9 relatively moves the condenser lens 14 in one direction along the first line 151, after the first oscillation process OP1 that oscillates the laser beam L to the light source 81 is completed, a switching process CP for switching the irradiation conditions of the laser beam L is started. Thereby, for example, compared with the case where the switching process CP is started after the first movement process MP1 is completed, during the second movement process MP2 in which the condenser lens 14 is relatively moved in the other direction along the second line 152, the second oscillation process OP2 for oscillating the laser beam L to the light source 81 can be started earlier. Therefore, according to the laser processing apparatus 1, the tact time can be shortened.

[0133] In the first processing example, the second processing example, the third processing example, and the fourth processing example, during the first movement process MP1, the control unit 9 executes a first detection process DP1 for detecting the height of the second surface 100b along the first line 151. After the control unit 9 finishes the first oscillation process OP1 and the first detection process DP1 as the first movement process MP1, a process of decelerating in the relative movement of the condenser lens 14 in the direction along the first line 151 is started. In this way, by starting the deceleration process after the first oscillation process OP1 is completed, further shortening of the tact time can be achieved. On the other hand, although vibration may occur when the deceleration process is started, by starting the deceleration process after the first detection process DP1 is completed, the occurrence of vibration during the first detection process DP1 can be suppressed, and as a result, the height of the second surface 100b can be accurately detected.

[0134] In the first processing example, the second processing example, the third processing example, and the fourth processing example, during the first movement process MP1, when the condenser lens 14 is located inside the object 100 when viewed from the optical axis direction of the condenser lens 14, the switching process CP is started. Thereby, compared with the case where the start of the switching process CP is waited until the condenser lens 14 is located outside the object 100 when viewed from the optical axis direction of the condenser lens 14, the tact time can be shortened.

[0135] In the first processing example and the third processing example, the control unit 9 executes a stop process SP that stops the relative movement of the condenser lens 14 in the directions along the first line 151 and the second line 152 between the first movement process MP1 and the second movement process MP2. As a result, by adjusting the time of the stop process SP, the switching process CP for switching the irradiation conditions of the laser beam L can be surely completed, so that the occurrence of processing defects can be suppressed.

[0136] In the first processing example and the third processing example, during the stop process SP, the control unit 9 executes a third movement process MP3 that 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. As a result, the condenser lens 14 can be surely positioned at the start position of the second movement process MP2, so that the occurrence of processing defects can be suppressed.

[0137] In the first processing example and the third processing example, when the condenser lens 14 is located outside the object 100 when 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 the position along the first line 151 to the position along the second line 152. As a result, the condenser lens 14 can be surely positioned at the start position of the second movement process MP2, so that the occurrence of processing defects can be suppressed. [Modification Example]

[0138] The present invention is not limited to the above-described embodiments. For example, similar to the first processing example and the third processing example, in the second processing example and the fourth processing example, 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. According to this, before starting the second oscillation process OP2, the switching process CP for switching the irradiation conditions of the laser beam L can be surely completed, so that the tact time can be shortened while suppressing the occurrence of processing defects.

[0139] In the first processing example, the second processing example, the third processing example, and the fourth processing example, the switching process CP may include at least one of an output switching process and a 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 incident side surface of the laser beam L on the object 100, and may be other surfaces of the object 100. This is because in the distance measuring unit 17, the reflected light reflected by each surface is spatially separated from each other.

[0141] The control unit 9 stores a plurality of conditions for the laser beam L, each including, for example, "the value of the pulse width, the value of the repetition frequency, and the value of the output", and may execute the switching from "the conditions set for the first oscillation process OP1" to "the conditions set for the second oscillation process OP2" as the switching process.

Description of Reference Numerals

[0142] 1... Laser processing apparatus, 7... Support unit, 9... Control unit, 14... Condensing lens, 17... Distance measuring unit (detection unit), 32... Attenuator (adjustment unit), 36... Spatial light modulator, 81... Light source, 100... Object, 110... Modification region, 151... First line, 152... Second line, L... Laser beam, P, P1, P2... Condensing points, 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 support part for supporting an object, A light source for oscillating a laser beam, An adjustment part for adjusting the output of the laser beam oscillated by the light source, A spatial light modulator for modulating the laser beam oscillated by the light source, A condenser lens for condensing the laser beam whose output is adjusted by the adjustment part and which is modulated by the spatial light modulator, A control part for controlling at least the light source, the adjustment part, and the spatial light modulator, The control part, When forming a modified region along each of a first line and a second line set in the object by positioning a condensing point of the laser beam inside the object, A first movement process of relatively moving the condenser lens in one direction along the first line, A first oscillation process of oscillating the laser beam to the light source so that the condensing point relatively moves in the one direction along the first line during the first movement process, A second movement process of relatively moving the condenser lens in the other direction along the second line, A second oscillation process of oscillating the laser beam to the light source so that the condensing point relatively moves in the other direction along the second line during the second movement process, A switching process including at least one of a process of switching a set value of the output adjusted by the adjustment part and a process of switching a modulation pattern displayed by the spatial light modulator between the first oscillation process and the second oscillation process, The control part starts the switching process after ending the first oscillation process during the first movement process. A laser processing apparatus.

2. 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. The laser processing apparatus according to claim 1.

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

4. The control unit executes the switching process between the first oscillation process and the second movement process. The laser processing apparatus according to claim 1.

5. The laser processing apparatus further includes a detection unit for detecting the height of the surface of the object. The control unit further executes a detection process for detecting the height along the first line during the first movement process. The control unit starts a process of decelerating in the relative movement of the condenser lens in the direction along the first line after finishing the first oscillation process and the detection process as the first movement process. The laser processing apparatus according to claim 1.

6. The control unit starts the switching process when the condenser lens is located within the object when viewed from the optical axis direction of the condenser lens during the first movement process. The laser processing apparatus according to claim 1.

7. The control unit executes a process of relatively moving the condenser lens from the position along the first line to the position along the second line when the condenser lens is located outside the object when viewed from the optical axis direction of the condenser lens. The laser processing apparatus according to claim 1.

Images