Laser processing device and laser processing method

Abstract

To provide a laser processing apparatus and a laser processing method, capable of efficiently and accurately forming a modified region along each of a plurality of lines on an object.SOLUTION: A laser processing apparatus comprises: a support unit for supporting an object 100; a light source for emitting laser light; a spatial light modulator for modulating laser light; a light focusing unit for focusing laser light on the object 100 from one side in a Z direction; a moving unit for moving the light focusing unit relative to the support unit; and a control unit. In the case of taking a relative movement direction of a first focusing point of first processing light L1 and a second focusing point of second processing light L2 as an X direction and taking a direction perpendicular to the Z direction and the X direction as a Y direction, the control unit controls the spatial light modulator and the moving unit so that the first focusing point and the second focusing point move relatively along a first line 90a and a second line 90b on the object 100 in a state of the first focusing point and the second focusing point deviating from each other in the respective X and Y directions.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a laser processing apparatus and a laser processing method. [Background technology]

[0002] Known laser processing devices that irradiate a target object with laser light to form modified regions in the target object include devices that split the laser light into multiple processing beams and modulate the laser light so that the multiple processing beams are focused at different locations (see, for example, Patent Documents 1 and 2). Such laser processing devices are extremely effective in shortening processing time because they can form multiple rows of modified regions using multiple processing beams. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-223620 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-226012 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of an object including a substrate and a plurality of functional elements arranged in a matrix on the substrate, for example, the functional elements are becoming increasingly miniaturized. As the miniaturization of the functional elements progresses, the number of lines for cutting the object into individual functional elements increases and the spacing between adjacent lines becomes narrower. Therefore, it becomes important to efficiently and accurately form modified regions in the object along each of the multiple lines.

[0005] An object of the present invention is to provide a laser processing apparatus and a laser processing method that can efficiently and accurately form modified regions in an object along each of a plurality of lines. [Means for solving the problem]

[0006] a spatial light modulator that modulates the laser light emitted from the light source; a focusing unit that focuses the laser light modulated by the spatial light modulator on the object from one side in the Z direction; a moving unit that moves the focusing unit relative to the support; and a control unit that controls the spatial light modulator to branch the laser light into a first processing light and a second processing light, and controls the moving unit so that a first focusing point of the first processing light and a second focusing point of the second processing light move relatively along a first line and a second line on the object. When the relative movement direction of the first focusing point and the second focusing point is defined as the X direction and the direction perpendicular to the Z direction and the X direction is defined as the Y direction, the control unit controls the spatial light modulator and the moving unit so that the first focusing point and the second focusing point move relatively along the first line and the second line on the object, with the first focusing point and the second focusing point being shifted from each other in each of the X direction and the Y direction.

[0007] In this laser processing apparatus, the first focal point of the first processing light and the second focal point of the second processing light move relatively along the first and second lines on the object while being offset from each other in the X and Y directions. Because the first and second focal points are thus offset not only in the Y direction but also in the X direction, even if the spacing between the first and second lines (i.e., the distance between the first and second lines in the Y direction) becomes narrow, a sufficient distance between the first and second focal points is ensured, thereby suppressing deterioration of processing quality due to interference. Therefore, this laser processing apparatus can efficiently and accurately form modified regions on the object along each of the multiple lines.

[0008] In the laser processing apparatus of the present invention, the target includes a substrate and a plurality of functional elements arranged in a matrix on the substrate, a plurality of street areas extending in a grid pattern so as to pass between each of the plurality of functional elements, and the control unit may control the spatial light modulator and the moving unit so that the first and second focusing points, which are offset from each other in the X and Y directions, move relatively along the first and second lines with the first and second lines positioned in adjacent first and second street areas, respectively, among the plurality of street areas. This makes it possible to efficiently and accurately form modified regions in the target along the first and second lines when the first line is positioned in the first street area and the second line is positioned in the second street area.

[0009] In the laser processing apparatus of the present invention, the target object includes a substrate and a plurality of functional elements arranged in a matrix on the substrate, a plurality of street areas extending in a grid pattern so as to pass between each of the plurality of functional elements, and the control unit may control the spatial light modulator and the moving unit so that the first and second focusing points, which are offset from each other in the X and Y directions, move relatively along the first and second lines with the first and second lines positioned in each of the plurality of street areas. This makes it possible to efficiently and accurately form modified regions in the target along each of the first and second lines when the first and second lines are positioned in the same street area.

[0010] The laser processing apparatus of the present invention may further include a first light-blocking unit, and the control unit may control the spatial light modulator to branch the laser light into zeroth-order light and ±nth-order light (n is a natural number) including the first processing light and the second processing light, and the first light-blocking unit may block light of the zeroth-order light and ±nth-order light that is focused outside the first processing light and the second processing light at the object. This makes it possible to prevent damage to the object caused by light of the zeroth-order light and ±nth-order light that is focused outside the first processing light and the second processing light at the object (hereinafter referred to as "light branched outside the first processing light and the second processing light").

[0011] The laser processing apparatus of the present invention may further include an adjusting optical system having first and second optical elements functioning as lenses, the first and second optical elements being arranged so that the wavefront shape of the laser light at the spatial light modulator and the wavefront shape of the laser light at the focusing unit are similar to each other and the first and second optical elements form a bilaterally telecentric optical system, and the first light-blocking unit may be arranged on a Fourier plane between the first and second optical elements, thereby reliably blocking light branched to outside the first processing light and the second processing light.

[0012] In the laser processing device of the present invention, the first light-blocking unit may have a pair of first portions facing each other in the Y direction, and each of the pair of first portions may be movable along the Y direction. This makes it possible to adjust the distance between the pair of first portions according to the amount of deviation between the first and second focusing points in the Y direction, and to reliably block light branched to the outside of the first processing light and the second processing light.

[0013] In the laser processing apparatus of the present invention, the control unit may determine a distance between the pair of first portions based on the amount of deviation between the first and second focusing points in the Y direction, and control the first light blocking unit so that the pair of first portions face each other in the Y direction via the determined distance. This makes it possible to reliably block light branched to the outside of the first processing light and the second processing light even when the amount of deviation between the first and second focusing points in the Y direction is changed.

[0014] In the laser processing device of the present invention, the first light-blocking unit may have a pair of second portions facing each other in the X direction. This makes it possible to reliably block light branched to the outside of the first processing light and the second processing light, even when the amount of deviation between the first and second focusing points in the Y direction is changed, for example, by keeping the amount of deviation between the first and second focusing points in the X direction constant.

[0015] The laser processing apparatus of the present invention may further include a second light blocking unit that blocks the zero-order light and / or the unmodulated light, and the second light blocking unit may be movable forward and backward relative to the optical path of the zero-order light and / or the optical path of the unmodulated light. This makes it possible to prevent damage to the object caused by the zero-order light when the zero-order light is not used as either the first processing light or the second processing light. Also, it is possible to prevent damage to the object caused by the unmodulated light.

[0016] A laser processing method of the present invention is a laser processing method carried out by a laser processing apparatus including a support portion that supports an object, a light source that emits laser light, a spatial light modulator that modulates the laser light emitted from the light source, a focusing portion that focuses the laser light modulated by the spatial light modulator on the object from one side in the Z direction, and a moving portion that moves the focusing portion relative to the support portion, and includes: a first step of controlling the spatial light modulator so that the laser light branches into first processing light and second processing light; and a second step of controlling the moving portion so that a first focusing point of the first processing light and a second focusing point of the second processing light move relatively along a first line and a second line on the object, where the relative movement direction of the first focusing point and the second focusing point is defined as the X direction and the direction perpendicular to the Z direction and the X direction is defined as the Y direction, and in the first step, the spatial light modulator is controlled so that the first focusing point and the second focusing point are shifted from each other in each of the X direction and the Y direction.

[0017] According to this laser processing method, for the same reasons as those of the above-mentioned laser processing apparatus, modified regions can be formed efficiently and accurately in the object along each of the multiple lines. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a laser processing apparatus and a laser processing method that can efficiently and accurately form modified regions in an object along each of a plurality of lines. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a configuration diagram of a laser processing apparatus according to an embodiment; [Figure 2] 2 is a cross-sectional view of a portion of the spatial light modulator shown in FIG. 1. [Figure 3] 2 is a plan view of a first light-blocking section and a second light-blocking section shown in FIG. 1. FIG. [Figure 4] 2 is a plan view of an object to be processed by the laser processing device shown in FIG. 1. [Figure 5] FIG. 5 is a cross-sectional view of a portion of the object shown in FIG. [Figure 6] 5 is a schematic diagram showing a state in which a part of the object shown in FIG. 4 is irradiated with laser light. FIG. [Figure 7] 5 is a schematic diagram showing the positional relationship of a plurality of light-converging points in a part of the object shown in FIG. 4. FIG. [Figure 8] 4 is a schematic diagram showing the positional relationship of a plurality of light-converging points in the first light-blocking section and the second light-blocking section shown in FIG. 3. FIG. [Figure 9] 4 is a schematic diagram showing the positional relationship of a plurality of light-converging points in the first light-blocking section and the second light-blocking section shown in FIG. 3. FIG. [Figure 10] 2 is a flowchart of a control method carried out in the laser processing apparatus shown in FIG. [Figure 11] 2 is a plan view of a portion of an object machined by the laser machining apparatus shown in FIG. 1. [Figure 12] 2 is a table showing evaluation results of the amount of deviation in the laser processing device shown in FIG. [Figure 13] FIG. 10 is a schematic diagram showing the positional relationship of a plurality of focal points in a part of an object to which laser light irradiation is being performed according to a modified example. [Figure 14] FIG. 10 is a schematic diagram showing the positional relationship of a plurality of light-converging points on a part of an object according to a modified example. [Figure 15] 4 is a schematic diagram showing the positional relationship of a plurality of light-converging points in the first light-blocking section and the second light-blocking section shown in FIG. 3. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted. [Configuration of laser processing equipment]

[0021] As shown in FIG. 1, the laser processing apparatus 1 forms a modified region M in the object 100 by irradiating the object 100 with laser light L. The laser processing apparatus 1 includes a support unit 2, a light source 3, a spatial light modulator 4, an adjustment optical system 5, a first light blocking unit 6, a second light blocking unit 7, a condenser unit 8, a moving unit 9, a control unit 10, a housing 11, and a cover 12. The spatial light modulator 4, the adjustment optical system 5, the first light blocking unit 6, and the second light blocking unit 7 are disposed within the housing 11. The light source 3 is disposed on a top wall 11a of the housing 11 and is covered by the cover 12. The condenser unit 8 is attached to a bottom wall 11b of the housing 11. In the following description, three mutually orthogonal directions are referred to as the X direction, the Y direction, and the Z direction, respectively. In this embodiment, the X direction is a first horizontal direction, the Y direction is a second horizontal direction perpendicular to the first horizontal direction, and the Z direction is a vertical direction.

[0022] The support unit 2 is disposed below the housing 11. The support unit 2 supports the object 100. As an example, the support unit 2 adheres to a film (not shown) attached to the object 100, thereby supporting the object 100 with the surface 100a of the object 100 facing the light collecting unit 8. In this embodiment, the support unit 2 is movable along the X and Y directions, and is rotatable about an axis parallel to the Z direction.

[0023] The light source 3 emits laser light L. As an example, the light source 3 oscillates the laser light L, which is transmissive to the object 100, in pulses.

[0024] The spatial light modulator 4 modulates the laser light L emitted from the light source 3. In this embodiment, the spatial light modulator 4 is a reflective liquid crystal (LCOS: Liquid Crystal on Silicon) spatial light modulator (SLM), which modulates and reflects the incident laser light L.

[0025] The adjustment optical system 5 has a first optical element 51 and a second optical element 52 that function as lenses. The first optical element 51 and the second optical element 52 are arranged so that the wavefront shape of the laser light L at the spatial light modulator 4 and the wavefront shape of the laser light L at the light collecting unit 8 are similar to each other and the first optical element 51 and the second optical element 52 form a double-telecentric optical system. As an example, the first optical element 51 and the second optical element 52 are arranged so that the optical path distance between the spatial light modulator 4 and the first optical element 51 is a first focal length f1 of the first optical element 51, the optical path distance between the light collecting unit 8 and the second optical element 52 is a second focal length f2 of the second optical element 52, the optical path distance between the first optical element 51 and the second optical element 52 is the sum of the first focal length f1 and the second focal length f2 (i.e., f1 + f2), and the first optical element 51 and the second optical element 52 form a double-telecentric optical system. That is, the adjustment optical system 5 is a 4f optical system. The image of the laser light L on the reflecting surface of the spatial light modulator 4 (the image of the laser light L modulated by the spatial light modulator 4) is transferred (imaged) onto the entrance pupil plane of the light collecting unit 8 by the adjustment optical system 5.

[0026] The first light-shielding unit 6 and the second light-shielding unit 7 are disposed on a Fourier plane (i.e., a plane including the confocal point O) between the first optical element 51 and the second optical element 52. In this embodiment, the first light-shielding unit 6 and the second light-shielding unit 7 transmit only a first processing light L1 and a second processing light L2, which will be described later.

[0027] The focusing unit 8 focuses the laser light L modulated by the spatial light modulator 4 onto the object 100 (specifically, the object 100 supported by the support unit 2) from above (one side) in the Z direction. The focusing unit 8 has a focusing lens unit 81 and a drive mechanism 82. The focusing lens unit 81 is made up of, for example, a plurality of lenses. The focusing lens unit 81 has an entrance pupil plane onto which an image of the laser light L on the reflecting surface of the spatial light modulator 4 is transferred by the adjustment optical system 5. The drive mechanism 82 is made up of, for example, a piezoelectric element. The drive mechanism 82 moves the focusing lens unit 81 along the Z direction.

[0028] The moving unit 9 moves the light collecting unit 8 relative to the support unit 2. The moving unit 9 is a moving mechanism (including a driving source such as an actuator or a motor) that moves at least one of the light collecting unit 8 and the support unit 2 to move the light collecting unit 8 relative to the support unit 2. In this embodiment, the moving unit 9 moves the support unit 2 along each of the X and Y directions, rotates the support unit 2 about an axis parallel to the Z direction as a center line, and moves the housing 11 along the Z direction.

[0029] The control unit 10 controls the operation of each part of the laser processing device 1. The control unit 10 has a processing unit, a memory unit, and an input receiving unit. The processing unit is configured as a computer device including a processor, memory, storage, communication devices, etc. In the processing unit, the processor executes software (programs) loaded into the memory, etc., and controls reading and writing of data in the memory and storage, as well as communication via the communication devices. The memory unit is, for example, a hard disk, and stores various types of data. The input receiving unit is an interface unit that receives input of various types of data from an operator.

[0030] The laser processing apparatus 1 further includes an attenuator 13, a beam homogenizer 14, a λ / 2 wave plate 15, a surface observation unit 16, an AF unit 17, a plurality of mirrors 18a, 18b, 18c, 18d, 18e, and 18f, and a plurality of dichroic mirrors 19a, 19b, and 19c. The mirror 18a is disposed within a cover 12. The attenuator 13, the beam homogenizer 14, the λ / 2 wave plate 15, the surface observation unit 16, the AF (Auto-Focus) unit 17, a plurality of mirrors 18b, 18c, 18d, 18e, and 18f, and a plurality of dichroic mirrors 19a, 19b, and 19c are disposed within a housing 11.

[0031] In the laser processing apparatus 1, the laser light L emitted from the light source 3 travels horizontally within the cover 12, is reflected downward by the mirror 18a, and enters the housing 11. The laser light L that entered the housing 11 has its light intensity adjusted by the attenuator 13, is reflected horizontally by the mirror 18b, has its intensity distribution homogenized by the beam homogenizer 14, and then enters the spatial light modulator 4. The laser light L that entered the spatial light modulator 4 is modulated by the spatial light modulator 4 and is reflected diagonally upward, and then reflected upward by the mirror 18c.

[0032] The laser light L reflected by mirror 18c has its polarization direction changed by λ / 2 wave plate 15, then reflected horizontally by mirror 18d, and passes through first optical element 51 of adjustment optical system 5. The laser light L that passed through first optical element 51 is reflected downward by mirror 18e, and after a portion of the laser light L is blocked by first light blocking unit 6 and second light blocking unit 7, passes through second optical element 52 of adjustment optical system 5 and multiple dichroic mirrors 19b and 19c. The laser light L that passed through multiple dichroic mirrors 19b and 19c is focused on target 100 by focusing unit 8.

[0033] The surface observation unit 16 is a unit for observing the object 100. The surface observation unit 16 has an observation light source 16a and a photodetector 16b. In the surface observation unit 16, visible light VL1 emitted from the observation light source 211a is reflected by a mirror 18f and a plurality of dichroic mirrors 19a and 19b, then passes through a dichroic mirror 19c, and is focused on the object 100 by a focusing unit 8. Reflected light VL2 of the visible light VL1 reflected by the object 100 passes through the focusing unit 8 and the dichroic mirror 19c, is reflected by the dichroic mirror 19b, then passes through the dichroic mirror 19a, and is incident on the photodetector 16b.

[0034] The AF unit 17 is a unit for finely adjusting the distance between the condensing lens unit 81 of the focusing unit 8 and the surface 100a of the object 100. The AF unit 17 emits an AF laser beam LB1 and detects reflected light LB2 of the AF laser beam LB1 that is reflected by the surface 100a of the object 100, thereby acquiring height data of the surface 100a of the object 100. Based on the height data acquired by the AF unit 17, the control unit 10 controls, for example, the drive mechanism 82 of the focusing unit 8 so that the distance between the condensing lens unit 81 and the surface 100a of the object 100 is constant. [Configuration of spatial light modulator]

[0035] As shown in Figure 2, the spatial light modulator 4 is constructed by stacking a drive circuit layer 42, a pixel electrode layer 43, a reflective film 44, an alignment film 45, a liquid crystal layer 46, an alignment film 47, a transparent conductive film 48, and a transparent substrate 49 in this order on a semiconductor substrate 41.

[0036] The semiconductor substrate 41 is, for example, a silicon substrate. The drive circuit layer 42 forms an active matrix circuit on the semiconductor substrate 41. The pixel electrode layer 43 includes a plurality of pixel electrodes 43a arranged in a matrix along the surface of the semiconductor substrate 41. Each pixel electrode 43a is made of, for example, a metal material such as aluminum. A voltage is applied to each pixel electrode 43a by the drive circuit layer 42.

[0037] The reflective film 44 is, for example, a dielectric multilayer film. The alignment film 45 is provided on the surface of the liquid crystal layer 46 facing the reflective film 44, and the alignment film 47 is provided on the surface of the liquid crystal layer 46 opposite the reflective film 44. Each of the alignment films 45, 47 is formed of, for example, a polymer material such as polyimide, and the contact surfaces of each of the alignment films 45, 47 with the liquid crystal layer 46 are subjected to, for example, rubbing treatment. The alignment films 45, 47 align liquid crystal molecules 46a contained in the liquid crystal layer 46 in a fixed direction.

[0038] The transparent conductive film 48 is provided on the surface of the transparent substrate 49 on the alignment film 47 side, and faces the pixel electrode layer 43 with the liquid crystal layer 46 and the like sandwiched therebetween. The transparent substrate 49 is, for example, a glass substrate. The transparent conductive film 48 is formed of, for example, a light-transmitting and conductive material such as ITO. The transparent substrate 49 and the transparent conductive film 48 transmit the laser light L.

[0039] In the spatial light modulator 4 configured as described above, when a signal indicating a modulation pattern is input from the control unit 10 to the drive circuit layer 42, a voltage corresponding to the signal is applied to each pixel electrode 43a, and an electric field is formed between each pixel electrode 43a and the transparent conductive film 48. When this electric field is formed, the alignment direction of the liquid crystal molecules 46a in each region corresponding to each pixel electrode 43a in the liquid crystal layer 46 changes, and the refractive index of each region corresponding to each pixel electrode 43a changes. This state is the state in which the modulation pattern is displayed on the liquid crystal layer 46.

[0040] With a modulation pattern displayed on the liquid crystal layer 46, laser light L enters the liquid crystal layer 46 from the outside through the transparent substrate 49 and the transparent conductive film 48, is reflected by the reflective film 44, and is emitted from the liquid crystal layer 46 to the outside through the transparent conductive film 48 and the transparent substrate 49, whereby the laser light L is modulated according to the modulation pattern displayed on the liquid crystal layer 46. In this way, the spatial light modulator 4 makes it possible to modulate the laser light L (for example, modulate the intensity, amplitude, phase, polarization, etc. of the laser light L) by appropriately setting the modulation pattern to be displayed on the liquid crystal layer 46. [First light-blocking unit and second light-blocking unit]

[0041] As shown in FIG. 3 , the first light-shielding unit 6 has a pair of first portions 61 and a pair of second portions 62. The pair of first portions 61 face each other in the Y direction. In this embodiment, the pair of first portions 61 face each other in the Y direction, with a confocal point O sandwiched between the first optical element 51 and the second optical element 52 on the Fourier plane. Each first portion 61 is movable along the Y direction. Each first portion 61 is moved along the Y direction by a driving source (not shown), such as a motor, controlled by the control unit 10. The pair of second portions 62 face each other in the X direction. In this embodiment, the pair of second portions 62 face each other in the X direction, with a confocal point O sandwiched between the first optical element 51 and the second optical element 52 on the Fourier plane. Each second portion 62 is fixed such that the distance between the pair of second portions 62 is constant.

[0042] For example, when the laser light L is diffracted by the spatial light modulator 4 into zeroth-order light and ±nth-order light (n is a natural number), the second light blocking unit 7 is movable forward and backward relative to the optical path of the zeroth-order light and the optical path of the unmodulated light, and blocks the zeroth-order light and the unmodulated light while positioned on the optical path. In this embodiment, the second light blocking unit 7 is movable forward and backward relative to the confocal point O on the Fourier plane between the first optical element 51 and the second optical element 52, and blocks the zeroth-order light and the unmodulated light while positioned on the confocal point O. The second light blocking unit 7 is moved forward and backward by a drive source (not shown), such as a motor, controlled by the control unit 10. In this embodiment, the second light blocking unit 7 is an elongated member that extends along the X direction and is movable forward and backward along the X direction, but it may also be an elongated member that extends along another direction (e.g., the Y direction) and is movable forward and backward along the other direction. The unmodulated light is the laser light L incident on the spatial light modulator 4, which is emitted from the spatial light modulator 4 without being modulated by the spatial light modulator 4. For example, the laser light L incident on the spatial light modulator 4 is reflected by the outer surface of the transparent substrate 49 (the surface opposite to the transparent conductive film 48), which is the unmodulated light. [Object Configuration]

[0043] 4 and 5, the target object 100 has a substrate 101 and a plurality of functional elements 102. The plurality of functional elements 102 are arranged on the substrate 101 in a matrix.

[0044] The substrate 101 has a front surface 101a and a back surface 101b. The substrate 101 is, for example, a semiconductor substrate such as a silicon substrate. The substrate 101 is provided with a notch 101c indicating a crystal orientation. Note that the substrate 101 may be provided with an orientation flat instead of the notch 101c.

[0045] A plurality of functional elements 102 are provided on a surface 101a of the substrate 101. Each functional element 102 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 102 may be configured three-dimensionally by stacking a plurality of layers.

[0046] In the object 100, a plurality of street regions 103 extend in a grid pattern so as to pass between each of the plurality of functional elements 102. In this embodiment, a plurality of lines 90 are set on the object 100 so that one line 90 is located in one street region 103, and the object 100 is cut along each of the plurality of lines 90 for each functional element 102. As an example, each line 90 passes through the center of the street region 103. In this embodiment, the plurality of lines 90 are virtual lines set on the object 100 by the laser processing apparatus 1, but they may also be lines that are actually drawn on the object 100. Note that "one or more lines 90 are located in one street region 103" means that one or more lines 90 extend within and along one street region 103 when viewed from the Z direction. [Controller Functions]

[0047] As shown in FIG. 6, the object 100 is supported by the support 2 so that the laser light L is incident on the substrate 101 from the side of the multiple functional elements 102 (i.e., so that the laser light L is incident on the substrate 101 from a region of the surface 101a of the substrate 101 that corresponds to the street region 103). The function of the control unit 10 will be described below, focusing on adjacent first and second lines 90a and 90b among the multiple lines 90. Note that the control unit 10 functions similarly for all lines 90, with the adjacent first and second lines 90a and 90b being the smallest unit. The control unit 10 also functions similarly when the object 100 is supported by the support 2 so that the laser light L is incident on the substrate 101 from the side opposite to the multiple functional elements 102 (i.e., so that the laser light L is incident on the substrate 101 from the back surface 101b of the substrate 101).

[0048] As shown in FIGS. 1 and 6 , the control unit 10 controls the moving unit 9 to rotate the support unit 2 about an axis parallel to the Z direction. This causes the first line 90a and the second line 90b to extend along the X direction and be adjacent to each other in the Y direction. In this state, the control unit 10 controls the spatial light modulator 4 to split the laser beam L into the first processing beam L1 and the second processing beam L2 (first step), and controls the moving unit 9 to move the first focal point C1 of the first processing beam L1 and the second focal point C2 of the second processing beam L2 relatively along the first line 90a and the second line 90b on the object 100 (second step). Based on the height data acquired by the AF unit 17, the control unit 10 controls the driving mechanism 82 of the focusing unit 8 so that the first focal point C1 and the second focal point C2 are each located at a predetermined depth from the surface 101a. As a result of the above, modified regions M are formed inside the substrate 101 along the first lines 90a and the second lines 90b.

[0049] The branching of the laser beam L will be described in more detail. As shown in FIG. 7, the control unit 10 divides the laser beam L into a zero-order beam L0 and ±n-order beams L1, L2, which include a first processing beam L1 and a second processing beam L2. ±nThe spatial light modulator 4 is controlled so that the light is branched into ±n-th order light L (n is a natural number). ±n The plurality of light-converging points of the zeroth-order light L0 and the unmodulated light Lu are arranged at equal intervals on a straight line inclined with respect to both the X and Y directions on the object 100. -1 and the +1st order light L +1 In this embodiment, the first processing light L1 is located at the midpoint between the focal point of the first processing light L1 and the focal point of the second processing light L2. -1 The second processed light L2 is the +1st order light L +1 Therefore, the first condensing point C1 of the first processing light L1 and the second condensing point C2 of the second processing light L2 (see FIG. 6) are shifted from each other in both the Y direction and the X direction.

[0050] That is, the control unit 10 controls the spatial light modulator 4 and the moving unit 9 so that the first and second focus points C1 and C2 move relatively along the first line 90a and the second line 90b on the object 100 in a state in which the first and second focus points C1 and C2 are shifted from each other in each of the X and Y directions. In this embodiment, the control unit 10 controls the spatial light modulator 4 and the moving unit 9 so that the first and second focus points C1 and C2, which are shifted from each other in each of the X and Y directions, move relatively along the first line 90a and the second line 90b in a state in which the first line 90a and the second line 90b are located in the first street area 103a and the second street area 103b, respectively, that are adjacent to each other among the plurality of street areas 103.

[0051] Furthermore, the control unit 10 controls the 0th order light L0 and the ±nth order light L1 as shown in FIGS. ±n The first light blocking unit 6 is controlled so that the light focused outside the first processing light L1 and the second processing light L2 at the object 100 is blocked, and the second light blocking unit 7 is controlled so that the 0th order light L0 and the unmodulated light Lu are blocked. -1 The second processed light L2 is the +1st order light L +1 Therefore, the -2nd order light L -2and +2nd light L +2 The first light blocking section 6 blocks ±mth order light (m is a natural number of 2 or more) including the above.

[0052] The control of the first light blocking unit 6 and the second light blocking unit 7 by the control unit 10 will be described in more detail with reference to Fig. 10. First, the control unit 10 acquires processing conditions including the X-direction shift amount (the shift amount between the first and second focusing points C1 and C2 in the X direction) and the Y-direction shift amount (the shift amount between the first and second focusing points C1 and C2 in the Y direction) (S01 in Fig. 10), and determines a modulation pattern to be input to the spatial light modulator 4 (S02 in Fig. 10).

[0053] Next, the control unit 10 determines whether or not the pair of first portions 61 of the first light blocking unit 6 needs to be moved based on the acquired X-direction shift amount and Y-direction shift amount (S03 in FIG. 10). For example, as shown in FIG. 8, when the first processing light L1 is the −1st order light L -1 The second processed light L2 is the +1st order light L +1 In this case, the −2nd order light L -2 and +2nd light L +2 9, when it is assumed that the first processing light L1 is not blocked by the pair of second portions 62 of the first light blocking unit 6, the control unit 10 determines that the pair of first portions 61 needs to be moved. -1 The second processed light L2 is the +1st order light L +1 In this case, the −2nd order light L -2 and +2nd light L +2 is expected to be blocked by the pair of second portions 62 of the first light-blocking unit 6, the control unit 10 determines that movement of the pair of first portions 61 is not necessary.

[0054] When the control unit 10 determines that the pair of first portions 61 needs to be moved, it determines the distance between the pair of first portions 61 based on the amount of deviation in the Y direction (S04 in FIG. 10), and controls the first light blocking unit 6 so that the pair of first portions 61 face each other in the Y direction via the determined distance (S05 in FIG. 10). ±nThe plurality of light-converging points on the object 100 are arranged at equal intervals on a straight line tilted with respect to both the X and Y directions. Therefore, the control unit 10 calculates the −2nd order light L based on the amount of deviation in the Y direction. -2 and +2nd light L +2 The distance between the pair of first portions 61 can be determined so that ±m-th order light (m is a natural number of 2 or more) including the above is blocked by the first portions 61. On the other hand, when the control unit 10 determines that movement of the pair of first portions 61 is not necessary, it skips the processes of S04 and S05 in FIG. 10 .

[0055] Next, the control unit 10 determines whether or not it is necessary to move the second light blocking unit 7 based on the acquired processing conditions (S06 in FIG. 10). For example, as shown in FIGS. 8 and 9, when the first processing light L1 is the −1st order light L -1 The second processed light L2 is the +1st order light L +1 In this case, it is not necessary to irradiate the object 100 with the zero-order light L0 and the unmodulated light Lu, and therefore the control unit 10 determines that it is necessary to move the second light blocking unit 7. On the other hand, when the first processing light L1 or the second processing light L2 is the zero-order light L0, the control unit 10 determines that it is not necessary to move the second light blocking unit 7.

[0056] If the control unit 10 determines that it is necessary to move the second light blocking unit 7, it controls the second light blocking unit 7 so as to block the zero-order light L0 and the unmodulated light Lu (S07 in FIG. 10). On the other hand, if it determines that it is not necessary to move the second light blocking unit 7, it skips the process of S07 in FIG. 10.

[0057] Next, the control unit 10 starts irradiating the laser light L (S08 in FIG. 10). That is, the control unit 10 controls the light source 3 to emit the laser light L, and also controls the spatial light modulator 4 and the moving unit 9 so that the first and second focusing points C1 and C2 move relatively along the first line 90a and the second line 90b on the object 100 in a state where the first and second focusing points C1 and C2 are shifted from each other in the X and Y directions. [X-direction deviation and Y-direction deviation]

[0058] Fig. 11 is a plan view of a portion of an object 100 processed by the laser processing apparatus 1. As shown in Fig. 11, when focusing on multiple modified regions M extending in one direction in the object 100, the outer ends of the modified regions M (ends on the outer edge 104a side of the object 100) are located at the outer edge portion 104 of the object 100. In the multiple modified regions M extending in one direction, modified regions M whose X-direction distance from the outer edge 104a to the outer ends of the modified regions M is a first distance and modified regions M whose X-direction distance from the outer edge 104a to the outer ends of the modified regions M is a second distance that is greater than the first distance are arranged periodically (e.g., alternately). This is because, as described above, the first and second focusing points C1 and C2, which are offset from each other in the X and Y directions, are moved relatively along the first and second lines 90a and 90b, respectively, and this movement is performed in the same manner for all lines 90, with adjacent first and second lines 90a and 90b being the smallest unit. Here, the amount of X-direction shift is preferably smaller than the width (the width in the normal direction to the outer edge 104a) of the outer edge portion 104 surrounding the effective portion 105 in which the multiple functional elements 102 are formed. This allows all modified regions M to be formed so as to intersect with the outer edge 105a of the effective portion 105.

[0059] FIG. 12 is a table showing the evaluation results of the amount of deviation in the laser processing device 1. The "amount of deviation" in FIG. 12 means the amount of deviation in the X direction and the amount of deviation in the Y direction. As shown in FIG. 12, the amount of deviation in the X direction and the amount of deviation in the Y direction are each determined based on the margin of high-order light cut (0th-order light L0 and ±nth-order light L1). ±n Among them, only the first processing light L1 and the second processing light L2 are surely transmitted. In other words, the 0th order light L0 and the ±nth order light L ±nFrom the viewpoint of ensuring that only light focused outside the first processing light L1 and the second processing light L2 on the object 100 is blocked, the deviation is preferably 30 μm or more and 900 μm or less, and more preferably 100 μm or more and 900 μm or less. Furthermore, from the viewpoint of selecting the focusing unit 8 (the limit of the maximum pupil diameter of the focusing unit 8 that can achieve the NA for suitably forming the modified region M), the deviation amounts in the X direction and the Y direction are preferably 10 μm or more and 700 μm or less, and more preferably 10 μm or more and 300 μm or less. Therefore, the deviation amounts in the X direction and the Y direction are preferably 30 μm or more and 700 μm or less, and more preferably 100 μm or more and 300 μm or less. [Action and effect]

[0060] In the laser processing apparatus 1 and the laser processing method implemented by the laser processing apparatus 1, the first focal point C1 of the first processing light L1 and the second focal point C2 of the second processing light L2 move relatively along the first line 90a and the second line 90b on the target object 100 while being offset from each other in the X and Y directions. Because the first focal point C1 and the second focal point C2 are offset not only in the Y direction but also in the X direction, even if the spacing between the first line 90a and the second line 90b (i.e., the distance between the first line 90a and the second line 90b in the Y direction) becomes narrow, the distance between the first focal point C1 and the second focal point C2 is sufficiently secured, and deterioration of processing quality due to interference is suppressed. Therefore, the laser processing apparatus 1 can efficiently and accurately form modified regions M on the target object 100 along each of the multiple lines 90.

[0061] In the laser processing apparatus 1, the control unit 10 controls the spatial light modulator 4 and the moving unit 9 so that the first focus point C1 and the second focus point C2, which are offset from each other in the X and Y directions, move relatively along the first line 90a and the second line 90b, while the first line 90a and the second line 90b are located in adjacent first street region 103a and second street region 103b, respectively, among the plurality of street regions 103. This makes it possible to efficiently and accurately form modified regions M in the target object 100 along each of the first line 90a and the second line 90b when the first line 90a is located in the first street region 103a and the second line 90b is located in the second street region 103b.

[0062] In the laser processing device 1, the laser light L is divided into a zero-order light L0 and a ±n-order light L1, which include a first processing light L1 and a second processing light L2. ±n The control unit 10 controls the spatial light modulator 4 so that the 0th-order light L0 and the ±nth-order light L ±n The first light blocking unit 6 blocks the light that is focused outside the first processing light L1 and the second processing light L2 on the object 100. ±n Of these, it is possible to prevent damage to the object 100 caused by the light that is focused outside the first processing light L1 and the second processing light L2 at the object 100 (hereinafter referred to as "light that is branched outside the first processing light L1 and the second processing light L2").

[0063] In the laser processing apparatus 1, the first light-blocking unit 6 is disposed on the Fourier plane between the first optical element 51 and the second optical element 52. This makes it possible to reliably block light branched to the outside of the first processing light L1 and the second processing light L2.

[0064] In the laser processing device 1, the first light blocking unit 6 has a pair of first portions 61 facing each other in the Y direction, and the pair of first portions 61 are movable along the Y direction. This makes it possible to adjust the distance between the pair of first portions 61 according to the amount of deviation in the Y direction between the first focusing point C1 and the second focusing point C2, and to reliably block light branched outward from the first processing light L1 and the second processing light L2.

[0065] In the laser processing apparatus 1, the control unit 10 determines the distance between the pair of first portions 61 based on the amount of deviation in the Y direction between the first and second focusing points C1 and C2, and controls the first light blocking unit 6 so that the pair of first portions 61 face each other in the Y direction via the determined distance. This makes it possible to reliably block light branched to the outside of the first processing light L1 and the second processing light L2, even when the amount of deviation in the Y direction between the first and second focusing points C1 and C2 is changed.

[0066] In the laser processing apparatus 1, the first light-blocking unit 6 has a pair of second portions 62 facing each other in the X direction. As a result, even if the amount of deviation in the Y direction between the first and second focusing points C1 and C2 is changed, for example, by keeping the amount of deviation in the X direction between the first and second focusing points C1 and C2 constant, it is possible to reliably block the light branched outward from the first processing light L1 and the second processing light L2.

[0067] In the laser processing apparatus 1, the second light blocking unit 7, which blocks the zero-order light L0 and the unmodulated light Lu, can move forward and backward relative to the optical path of the zero-order light L0 and the optical path of the unmodulated light Lu. This makes it possible to prevent damage to the object 100 caused by the zero-order light L0 when the zero-order light L0 is not used as either the first processing light L1 or the second processing light L2. It also makes it possible to prevent damage to the object 100 caused by the unmodulated light Lu. [Variations]

[0068] The present invention is not limited to the above embodiment. For example, as shown in Fig. 13, the control unit 10 may control the spatial light modulator 4 so that the laser beam L is branched into a first processing beam L1, a second processing beam L2, and a third processing beam L3, and may control the moving unit 9 so that the first focal point of the first processing beam L1, the second focal point of the second processing beam L2, and the focal point of the third processing beam L3 move relatively along a first line 90a, a second line 90b, and a third line 90c on the object 100. In other words, the control unit 10 may control the spatial light modulator 4 so that the laser beam L is branched into multiple beams including multiple processing beams, and may control the moving unit 9 so that the multiple focal points of the multiple processing beams move relatively along multiple lines on the object 100.

[0069] In the example shown in FIG. 13, the first processing light L1 is the −1st order light L -1 The second processing light L2 is the 0th order light L0, and the third processing light L3 is the +1st order light L +1 In this example, the control unit 10 also controls the spatial light modulator 4 and the moving unit 9 so that the first focal point of the first processing light L1, the second focal point of the second processing light L2, and the third focal point of the third processing light L3 move relatively along the first line 90a, the second line 90b, and the third line 90c on the object 100, while the first focal point of the first processing light L1 and the second focal point of the second processing light L2 are shifted from each other in the X direction and the Y direction and the second focal point of the second processing light L2 and the third focal point of the third processing light L3 are shifted from each other in the X direction and the Y direction.

[0070] 14, in a state where the first line 90a and the second line 90b are located in each of a plurality of street regions 103 (i.e., in a state where the first line 90a and the second line 90b are located in one street region 103), the control unit 10 may control the spatial light modulator 4 and the moving unit 9 so that the first focusing point C1 and the second focusing point C2, which are offset from each other in the X direction and the Y direction, move relatively along the first line 90a and the second line 90b. In this way, when the first line 90a and the second line 90b are located in the same street region 103, it is possible to efficiently and accurately form the modified region M in the object 100 along each of the first line 90a and the second line 90b. In this case as well, the 0th-order light L0 and the ±nth-order light L ±n Among these, the light condensed outside the first processing light L1 and the second processing light L2 at the object 100 may be blocked by the first light blocking unit 6. Also in this case, the zero-order light L0 and the unmodulated light Lu may be blocked by the second light blocking unit 7.

[0071] The first light-shielding unit 6 and the second light-shielding unit 7 are not limited to being arranged on the Fourier plane between the first optical element 51 and the second optical element 52. The first light-shielding unit 6 and the second light-shielding unit 7 may be arranged immediately before the entrance pupil plane of the light-collecting unit 8, for example.

[0072] In the first light-shielding unit 6, each of the first portions 61 may be fixed such that the distance between the pair of first portions 61 is constant. In this case, the amount of deviation between the first and second focus points C1 and C2 in the X direction may be adjusted within the range of the distance between the pair of first portions 61. In the first light-shielding unit 6, each of the second portions 62 may be movable in the X direction. The first light-shielding unit 6 may have a pair of first portions 61 but not a pair of second portions 62. The first light-shielding unit 6 may have a pair of second portions 62 but not a pair of first portions 61. For example, when the optical path of the zero-order light is deviated from the optical path of the unmodulated light, the second light-shielding unit 7 may be configured to block at least one of the zero-order light and the unmodulated light.

[0073] The first line 90a and the second line 90b are not limited to those extending along a predetermined straight line, but may extend along a predetermined curve. When the first line 90a and the second line 90b extend along a predetermined curve, the relative movement direction of the first focus point C1 and the second focus point C2 that move relatively along the first line 90a and the second line 90b is the tangent direction of the curve.

[0074] In the above embodiment, the X direction is the first horizontal direction, the Y direction is the second horizontal direction perpendicular to the first horizontal direction, and the Z direction is the vertical direction, but the X direction, Y direction, and Z direction are not limited to these respective directions. For example, the Z direction may be a direction that intersects with the vertical direction.

[0075] 15, the control unit 10 may control the spatial light modulator 4 and the moving unit 9 so that the first and second focusing points C1 and C2 are shifted from each other at least in the Y direction on the object, and the first and second focusing points C1 and C2 are moved relatively along the first and second lines. In this case, the 0th-order light L0 and the ±nth-order light L ±n Among these, the light condensed outside the first processing light L1 and the second processing light L2 at the object 100 may be blocked by the first light blocking unit 6. Also in this case, the zero-order light L0 and the unmodulated light Lu may be blocked by the second light blocking unit 7. [Explanation of symbols]

[0076] 1...laser processing device, 2...supporting portion, 3...light source, 4...spatial light modulator, 5...adjusting optical system, 6...first light blocking portion, 7...second light blocking portion, 8...light focusing portion, 9...moving portion, 10...control portion, 51...first optical element, 52...second optical element, 61...first portion, 62...second portion, 90...line, 90a...first line, 90b...second line, 100...object, 101...substrate, 102...functional element, 103...street area, 103a...first street area, 103b...second street area, C1...first focusing point, C2...second focusing point, L...laser light, L1...first processing light, L2...second processing light, L0...zeroth order light, L ±n ...±nth order light, Lu...unmodulated light, M...modified region.

Claims

1. a support portion that supports the object; a light source that emits laser light; a spatial light modulator that modulates the laser light emitted from the light source; a focusing unit that focuses the laser light modulated by the spatial light modulator onto the object from one side in the Z direction; a moving unit that moves the light collecting unit relative to the support unit; a control unit that controls the spatial light modulator so that the laser beam is branched into a first processing beam and a second processing beam, and controls the moving unit so that a first focal point of the first processing beam and a second focal point of the second processing beam move relatively along a first line and a second line on the object; a first light blocking unit; an adjustment optical system having a first optical element and a second optical element that function as lenses, a relative movement direction of the first and second focusing points is defined as an X direction, and a direction perpendicular to the Z direction and the X direction is defined as a Y direction, wherein the control unit controls the spatial light modulator and the moving unit so that the first and second focusing points move relatively along the first line and the second line on the object in a state where the first and second focusing points are shifted from each other in each of the X direction and the Y direction; the control unit controls the spatial light modulator so that the laser beam is branched into a zero-order beam and ±n-th order beams (n is a natural number) including the first processing beam and the second processing beam; the first light blocking unit blocks light of the zeroth order light and the ±nth order light that is condensed outside the first processing light and the second processing light at the object, the first optical element and the second optical element are arranged such that a wavefront shape of the laser light at the spatial light modulator and a wavefront shape of the laser light at the light-collecting unit are similar to each other, and the first optical element and the second optical element form a double-telecentric optical system, the first light blocking unit is disposed on a Fourier plane between the first optical element and the second optical element, the first light-blocking unit has a pair of first portions facing each other in the Y direction, A laser processing apparatus, wherein each of the pair of first portions is movable along the Y direction.

2. the object includes a substrate and a plurality of functional elements arranged in a matrix on the substrate; In the object, a plurality of street areas extend in a grid pattern so as to pass between the plurality of functional elements, 2. The laser processing device according to claim 1, wherein the control unit controls the spatial light modulator and the moving unit so that the first and second focusing points, which are shifted from each other in the X direction and the Y direction, move relatively along the first and second lines, with the first and second lines positioned in adjacent first and second street areas, respectively, among the plurality of street areas.

3. the object includes a substrate and a plurality of functional elements arranged in a matrix on the substrate; In the object, a plurality of street areas extend in a grid pattern so as to pass between the plurality of functional elements, 2. The laser processing apparatus according to claim 1, wherein the control unit controls the spatial light modulator and the moving unit so that the first and second focusing points, which are shifted from each other in the X direction and the Y direction, move relatively along the first and second lines while the first and second lines are positioned in each of the plurality of street areas.

4. The laser processing apparatus according to any one of claims 1 to 3, wherein the control unit determines a distance between the pair of first portions based on the amount of deviation between the first focal point and the second focal point in the Y direction, and controls the first light-blocking unit so that the pair of first portions face each other in the Y direction via the determined distance.

5. 5. The laser processing device according to claim 1, wherein the first light blocking portion has a pair of second portions facing each other in the X direction.

6. further comprising a second light blocking unit that blocks the zero-order light and / or the unmodulated light; 6. The laser processing device according to claim 1, wherein the second light blocking section is movable forward and backward relative to the optical path of the zero-order light and / or the optical path of the unmodulated light.

7. A support part that supports an object; a light source that emits laser light; a spatial light modulator that modulates the laser light emitted from the light source; a focusing unit that focuses the laser light modulated by the spatial light modulator onto the object from one side in the Z direction; a moving unit that moves the light collecting unit relative to the support unit; a control unit that controls the spatial light modulator so that the laser beam is branched into a first processing beam and a second processing beam, and controls the moving unit so that a first focal point of the first processing beam and a second focal point of the second processing beam move relatively along a first line and a second line on the object; a first light blocking unit; a second light blocking unit that blocks the zero-order light and / or the unmodulated light, a relative movement direction of the first and second focusing points is defined as an X direction, and a direction perpendicular to the Z direction and the X direction is defined as a Y direction, wherein the control unit controls the spatial light modulator and the moving unit so that the first and second focusing points move relatively along the first line and the second line on the object in a state where the first and second focusing points are shifted from each other in each of the X direction and the Y direction; the control unit controls the spatial light modulator so that the laser beam is branched into a zero-order beam and ±n-th order beams (n is a natural number) including the first processing beam and the second processing beam; the first light blocking unit blocks light of the zeroth order light and the ±nth order light that is condensed outside the first processing light and the second processing light at the object, The laser processing device, wherein the second light blocking unit is movable forward and backward relative to the optical path of the zero-order light and / or the optical path of the unmodulated light.

Images