Laser processing apparatus and laser processing method

Abstract

The present invention provides a laser processing apparatus and a laser processing method that can suppress the narrowing of the range for tracking processing. The laser processing apparatus (1) includes a control unit (6). The control unit (6) performs the following processes: an acquisition process, which acquires displacement information representing the displacement of the first surface (11a) of the object (11) in the Z direction; an association process, which associates a specific value of a range of displacements including the center value of the displacement, i.e., the center range, with a reference voltage of the driving voltage of the actuator (8) based on the displacement information; and a processing process, which drives the actuator (8) with the reference voltage as the center, thereby adjusting the position of the focal point (C) of the laser (L) in the Z direction according to the displacement, and moving the focal point (C) relative to the line (A) in the X direction, and performing laser processing of the object (11) along the line (A).

Description

Technical Field

[0001] This invention relates to laser processing apparatus and laser processing method. Background Technology

[0002] Patent Document 1 describes a laser cutting apparatus. This laser cutting apparatus includes a stage for moving a wafer, a laser head for irradiating the wafer with laser light, and a control unit for controlling each part. The laser head includes a laser source that emits a processing laser for forming a modified region inside the wafer, a dichroic mirror and a focusing lens arranged sequentially in the optical path of the processing laser, and an autofocus (AF) device.

[0003] Patent Document 1: Japanese Patent No. 5743123 Summary of the Invention

[0004] In the apparatus described in Patent Document 1, a calibration operation is performed to measure the output characteristics of the autofocus error signal. During the calibration operation, the stage is controlled so that the reference position of the central portion of the wafer is directly below the focusing lens. Then, under the control of a second actuator, the focusing lens group, which helps adjust the focusing position of the laser used for autofocus (AF), is moved. At this time, the autofocus error signal is zero. Thus, the focusing point of the laser used for AF is aligned with the surface of the wafer.

[0005] Furthermore, by controlling the first actuator, while moving the focusing lens that concentrates the AF laser and the processing laser onto the wafer across the entire movable range, the output characteristics of the autofocus error signal are measured, and this output characteristic is maintained as a lookup table. Thus, in the apparatus described in Patent Document 1, the AF device is calibrated at a reference position in the central part of the wafer before laser processing.

[0006] However, as mentioned above, regardless of the distribution of displacement on the wafer surface, calibration is always performed at a reference position in the central part of the wafer. If the actuator is to be driven up and down around the height of the wafer surface at this reference position, the following problem arises. That is, for example, if the reference position is the upper (or lower) limit of the height of the wafer surface, in actual processing, only the lower (or upper) side of the center of the actuator's movable range is used, and the amount of displacement of the wafer surface exceeding the actuator's movable range increases.

[0007] Typically, the range of displacement that an AF device (displacement sensor) can measure on the wafer surface is greater than the range of motion of the condenser lens actuator. Therefore, in the portion of the wafer surface where the displacement exceeds the actuator's range of motion, even if the displacement can be measured, it is difficult to perform the corresponding processing (tracking processing) that involves appropriately moving the condenser lens according to the displacement. In other words, in this case, the range of tracking processing becomes narrower.

[0008] The purpose of this invention is to provide a laser processing apparatus and laser processing method that can suppress the narrowing of the range of traceable processing.

[0009] The laser processing apparatus of the present invention comprises: a support for supporting an object including a first surface and a second surface opposite to the first surface; a laser irradiation unit for irradiating the object supported by the support with laser light from the first surface side via a focusing lens; an actuator for driving the focusing lens along a Z-direction from the second surface toward the first surface; a first moving unit for moving at least one of the support and the laser irradiation unit so that the focusing point of the laser light moves relative to the object along an X-direction intersecting the Z-direction; and a control unit for controlling at least the actuator, the laser irradiation unit, and the first moving unit, and irradiating the object. When laser processing is performed on an object, the control unit performs the following processes: acquisition process, which acquires displacement information representing the displacement of the first surface in the Z direction; association process, which, after the acquisition process, associates a specific value of the range of the displacement, including the center value of the displacement, i.e., the center range, with a reference voltage of the actuator's drive voltage, based on the displacement information; processing process, which, after the association process, drives the actuator with the reference voltage as the center, thereby adjusting the position of the laser focus point in the Z direction according to the displacement, and moving the focus point relative to a line along the X direction, and performing laser processing on the object along the line.

[0010] The laser processing method of the present invention performs laser processing by controlling at least the following components: a laser irradiation unit for irradiating an object supported by a support unit with a second surface including a first surface and a second surface opposite to the first surface from the first surface side with a laser from the first surface side; an actuator for driving the laser-focusing lens along the Z direction from the second surface toward the first surface; and a first moving unit for moving at least one of the support unit and the laser irradiation unit so that the laser focusing point moves relative to the object along the X direction intersecting the Z direction. The laser processing method includes the following steps: an acquisition step for acquiring displacement information representing the displacement of the first surface with respect to the Z direction; an association step for associating, after the acquisition step, based on the displacement information, a specific value of a range of displacements including the center value of the displacement, i.e., the center range, with a reference voltage of the actuator's driving voltage; and a processing step for associating, after the association step, driving the actuator with the reference voltage as the center, thereby adjusting the position of the laser focusing point with respect to the Z direction according to the displacement, and moving the focusing point relative to the object along a line along the X direction, and performing laser processing along the line.

[0011] In these apparatuses and methods, firstly, displacement information representing the displacement of a first face of an object in the Z direction is acquired. Then, based on the acquired displacement information, a specific value representing a portion of the displacement of the first face of the object (i.e., the center range) is associated with a reference voltage for the actuator's drive voltage. Furthermore, by driving the actuator around this reference voltage, while adjusting the position of the laser focus point in the Z direction according to the displacement of the first face of the object, the focus point is relatively moved along a line in the X direction, and laser processing (tracking processing) of the object is performed along the line. Therefore, during tracking processing, at least the use of only the lower or upper side of the center of the actuator's movable range is avoided. Thus, compared to the case where the displacement amount (height) of the first face at the center of the object is always associated with the reference voltage of the actuator, the narrowing of the range for tracking processing can be suppressed.

[0012] In the laser processing apparatus of the present invention, the specific value may be the center value of the displacement. In this case, the lower and upper sides of the center of the actuator's movable range are used equally during tracking processing. Therefore, the narrowing of the range in which tracking processing can be performed is reliably suppressed.

[0013] In the laser processing apparatus of the present invention, a displacement sensor may also be provided, which is moved integrally with the laser irradiation unit, for measuring the displacement of the first surface and acquiring displacement information by emitting measurement light toward the object and inputting reflected light of the measurement light. In this case, displacement information representing the displacement of the first surface of the object can be acquired using the displacement sensor.

[0014] In the laser processing apparatus of the present invention, the control unit may also continuously measure and acquire displacement information using a displacement sensor. In this case, displacement information that is more consistent with the actual displacement of the first surface of the object can be acquired.

[0015] In the laser processing apparatus of the present invention, the control unit may also discretely measure displacement and acquire displacement information at multiple locations within the first surface using displacement sensors. In this case, the time required for acquisition and processing can be shortened.

[0016] In the laser processing apparatus of the present invention, a second moving unit may be included for moving the laser irradiation unit and the displacement sensor relative to the object along the Z-direction. The control unit performs the following processing in the association process: a first processing step, in which the laser irradiation unit and the displacement sensor are moved to a first position where the displacement of the first surface is a specific value, controlled by the first moving unit; a second processing step, after the first processing step, in which the laser irradiation unit and the displacement sensor are moved relative to each other along the Z-direction, controlled by the second moving unit, to measure the light focusing onto the first surface; and a third processing step, after the second processing step, in which the measured value of the displacement sensor when the light is focused onto the first surface is associated with a reference voltage. In this way, in the association process, the actual measured value of the displacement of the first surface of the object can be associated as a specific value with the reference voltage of the actuator's drive voltage.

[0017] In the laser processing apparatus of the present invention, a second moving unit may be included for moving the laser irradiation unit and the displacement sensor relative to the object along the Z-direction. The control unit performs the following processes in the association process: a fourth process, whereby, under the control of the first moving unit, the laser irradiation unit and the displacement sensor are moved to a second position where the displacement of the first surface is a lower or upper limit value; a fifth process, after the fourth process, where, under the control of the second moving unit, the laser irradiation unit and the displacement sensor are moved relative to each other along the Z-direction in a manner that measures the light focusing onto the first surface; a sixth process, after the fifth process, whereby the offset value, including the measured value of the displacement sensor's displacement when the light focuses onto the first surface plus the offset value, is set such that it is contained within the center range, and the offset value is associated with a reference voltage as a specific value. In this way, in the association process, the offset value, which is the actual measured value of the displacement away from the first surface of the object, can be associated with a reference voltage of the actuator's drive voltage as a specific value.

[0018] In the laser processing apparatus of the present invention, the control unit may perform the following processing between the acquisition processing and the association processing: a determination processing, which determines whether the displacement exceeds the movable range of the actuator; a notification processing, which notifies the control unit if the result of the determination processing is that the displacement exceeds the movable range; and if the result of the determination processing is that the displacement does not exceed the movable range, the control unit performs the association processing and the processing processing. In this case, it is possible to identify when the displacement of the first surface of the object exceeds the movable range of the actuator.

[0019] In the laser processing apparatus of the present invention, the control unit may perform a determination process between the acquisition process and the association process to determine whether the displacement exceeds the movable range of the actuator. If the result of the determination process is that the displacement exceeds the movable range, the control unit divides the line into multiple parts such that the displacement is within the movable range, and performs association processing and processing on each part. In this case, the range of tracking processing that can be performed is expanded.

[0020] According to the present invention, a laser processing apparatus and a laser processing method are provided that can suppress the narrowing of the range in which tracking processing can be performed. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the structure of a laser processing apparatus according to one embodiment.

[0022] Figure 2 It means Figure 1 The diagram shows the structure of the laser irradiation section.

[0023] Figure 3 This is a diagram illustrating an example of laser processing (tracking processing).

[0024] Figure 4 This is a diagram showing the relationship between the displacement sensor and the actuator.

[0025] Figure 5 It is a diagram used to illustrate the problem points in the tracking process.

[0026] Figure 6 This is a flowchart illustrating an example of a laser processing method.

[0027] Figure 7 It is a diagram used to illustrate the problem points in the tracking process.

[0028] Figure 8 This is a flowchart illustrating the laser processing method of the first embodiment.

[0029] Figure 9 It means Figure 8 The diagram illustrates the function and effect of the laser processing method.

[0030] Figure 10 It is a diagram used to illustrate the problem points in the tracking process.

[0031] Figure 11 This is a flowchart illustrating the laser processing method of the second embodiment.

[0032] Figure 12 It means Figure 11 The diagram shows the effects and benefits of laser processing.

[0033] Figure 13 This is a flowchart illustrating the laser processing method of the third embodiment.

[0034] Figure 14 This is a flowchart illustrating the laser processing method according to the fourth embodiment.

[0035] Figure 15 This is a flowchart illustrating the laser processing method according to the fifth embodiment.

[0036] Figure 16 It is a graph representing the situation where the displacement of an object exceeds the movable range of the actuator.

[0037] Figure 17 This is a flowchart illustrating the laser processing method according to the fifth embodiment.

[0038] Figure 18 This is a flowchart illustrating the laser processing method according to the fifth embodiment.

[0039] Figure 19 This is a flowchart illustrating the laser processing method according to the fifth embodiment.

[0040] Figure 20 A top view of the object used to illustrate the variation.

[0041] Figure 21 A graph illustrating the voltage of the displacement sensor in the modified example. Detailed Implementation

[0042] Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. Furthermore, in the various figures, the same or equivalent parts are sometimes labeled with the same symbols, and repeated descriptions are omitted. Additionally, in the various figures, an orthogonal coordinate system defined by the X-axis, Y-axis, and Z-axis is sometimes indicated.

[0043] [Overview of Laser Processing Equipment and Laser Processing]

[0044] Figure 1 This is a schematic diagram showing the structure of a laser processing apparatus according to one embodiment. Figure 2 It means Figure 1 The diagram shows the structure of the laser irradiation section. Figure 2 The diagram shows a hypothetical line A representing the predetermined laser processing. (Example) Figure 1 and Figure 2 As shown, the laser processing apparatus 1 includes a stage (support) 2, a laser irradiation unit 3, a drive unit (moving unit) 4 and 5, and a control unit 6. The laser processing apparatus 1 is a device for forming a modified region 12 on an object 11 by irradiating the object 11 with a laser L.

[0045] Stage 2 supports object 11 by holding a thin film attached to, for example, object 11. Stage 2 is rotatable about an axis parallel to the Z direction. Stage 2 is also movable along the X and Y directions. Furthermore, the X and Y directions are first and second horizontal directions that intersect (orthogonal), and the Z direction is a vertical direction. Object 11 has a first surface 11a and a second surface 11b opposite to the first surface 11a. Object 11 is, for example, a wafer containing a semiconductor (as an example, a silicon wafer).

[0046] The laser irradiation unit 3 focuses a transmissive laser L onto the object 11. If the laser L is focused into the interior of the object 11 supported by the stage 2, the laser L is specifically absorbed at the point corresponding to the focusing point C, forming a modified region 12 inside the object 11. Furthermore, the focusing point C is the point where the laser L is focused. However, the focusing point C can be a region within a defined range from the position where the laser L's beam intensity is highest or the centroid of the beam intensity, for example, when the laser L is modulated according to the modulation pattern indicated by the spatial light modulator 7 (e.g., when various aberrations are imparted), i.e., when the laser L is not focused at a single point.

[0047] The modified region 12 is a region whose density, refractive index, mechanical strength, and other physical properties differ from those of the surrounding unmodified region. Examples of modified regions 12 include melt-processed regions, cracked regions, insulation-damaged regions, and regions with refractive index changes. The modified region 12 is formed by cracks extending from the modified region 12 toward the incident side of the laser L and the opposite side. This modified region 12 and the cracks are used, for example, for cutting the object 11.

[0048] As an example, if the stage 2 is moved along the X direction and the focusing point C is moved relative to the object 11 along the X direction, multiple modified light spots 12s are formed in a row along the X direction. A modified light spot 12s is formed by irradiation with a pulse of laser L. A row of modified regions 12 is a collection of multiple modified light spots 12s arranged in a row. Adjacent modified light spots 12s are sometimes connected and sometimes separated depending on the relative moving speed of the focusing point C relative to the object 11 and the repetition frequency of the laser L.

[0049] The drive unit 4 includes a first unit 41 that moves the stage 2 in one direction within a plane intersecting (or orthogonal) to the Z direction, and a second unit 42 that moves the stage 2 in other directions within the plane intersecting (or orthogonal) to the Z direction. As an example, the first unit 41 moves the stage 2 along the X direction, and the second unit 42 moves the stage 2 along the Y direction. Additionally, the drive unit 4 rotates the stage 2 about an axis parallel to the Z direction. The drive unit 5 supports the laser irradiation unit 3. The drive unit 5 moves the laser irradiation unit 3 along the X, Y, and Z directions. With the laser L focusing point C formed, the focusing point C moves relative to the object 11 by moving the stage 2 and / or the laser irradiation unit 3. That is, the drive units 4 and 5 are a first moving unit and a second moving unit that move at least one of the stage 2 and the laser irradiation unit 3 to move the focusing point C of the laser L relative to the object 11.

[0050] The control unit 6 controls the operation of the stage 2, the laser irradiation unit 3, and the drive units 4 and 5. The control unit 6 includes a processing unit, a storage unit, and an input receiving unit (not shown). The processing unit is configured as a computer device including a processor, memory, storage, and communication devices. In the processing unit, the processor executes software (programs) read into the memory, controls the reading and writing of data in the memory and storage, and controls communication performed by the communication devices. The storage unit, such as a hard disk, stores various types of data. The input receiving unit is an interface unit that displays various information and receives various types of input from the user. The input receiving unit constitutes a GUI (Graphical User Interface).

[0051] like Figure 2 As shown, the laser irradiation unit 3 includes a light source 31, a spatial light modulator 7, an actuator 8, a displacement sensor 9, a condenser lens 33, and a mirror 34. The light source 31 outputs laser light L via, for example, pulse oscillation. Alternatively, the laser irradiation unit 3 may be configured to not have a light source 31 and instead introduce laser light L from outside the laser irradiation unit 3.

[0052] The spatial light modulator 7 modulates the laser L output from the light source 31 according to a modulation pattern formed on the liquid crystal layer, for example. The condenser lens 33 focuses the laser L modulated by the spatial light modulator 7 and output from the spatial light modulator 7 toward the object 11. That is, the laser irradiation unit 3 is used to irradiate the object 11 supported by the stage 2 with laser L from the first surface 11a side via the condenser lens 33.

[0053] Mirror 34 is positioned in front of condenser lens 33 (in this case, between condenser lens 33 and spatial light modulator 7) in the optical path of laser L. Mirror 34 allows laser L to pass through condenser lens 33.

[0054] The displacement sensor 9 outputs a measuring laser LA. A mirror 34 is positioned in the optical path of the measuring laser LA, reflecting the measuring laser LA towards the condenser lens 33. Thus, the measuring laser LA illuminates the object 11 along the same optical axis as the laser L. In other words, the displacement sensor 9 is coaxially configured with the laser L. The displacement sensor 9 receives the reflected light LR caused by the object 11 from the measuring laser LA via the condenser lens 33 and the mirror 34. The displacement sensor 9 outputs information about the reflected light LR as displacement information related to the displacement of the first surface 11a of the object 11 (which is the height in the Z-axis direction, including concavity, convexity, and tilt) to the control unit 6. This displacement information is, for example, the voltage value of the displacement sensor 9 corresponding to the reflected light LR (hereinafter sometimes referred to as "displacement sensor voltage").

[0055] Thus, the laser processing apparatus 1 includes a displacement sensor 9, which is integrally movable with the laser irradiation unit 3, for measuring displacement information by outputting a measuring laser (measuring light) LA toward the object 11 and inputting the reflected light LR of the measuring laser LA. Furthermore, the control unit 6 can acquire displacement information (displacement sensor voltage) representing the displacement of the first surface 11a of the object 11 by controlling the displacement sensor 9.

[0056] Furthermore, as described above, the displacement sensor 9 is a sensor coaxial with the laser L, and as an example, it is an astigmatic sensor, etc. However, the displacement sensor 9 can also be a sensor coaxial with the laser L. In this case, the displacement sensor 9 can be a triangulation sensor, a laser confocal sensor, a white confocal sensor, a beam splitting interferometer sensor, an astigmatic sensor, etc.

[0057] Actuator 8 is disposed on condenser lens 33. Actuator 8 is used to drive condenser lens 33 along the Z direction. Actuator 8 drives condenser lens 33 along the Z direction by extending and retracting according to the magnitude of the applied driving voltage, with the extension amount when a reference voltage is applied as the center. The Z direction here is the direction from the second surface 11b of object 11 toward the first surface 11a.

[0058] As described above, the control unit 6 is configured as a computer device, and at least controls the stage 2, the laser irradiation unit 3 including the actuator 8 and the displacement sensor 9, and the drive units 4 and 5, and irradiates the object 11 with laser L to perform laser processing on the object 11. Details of the processing of the control unit 6 will be described later.

[0059] Laser processing is performed in the laser processing apparatus 1 described above, as follows. Figure 3 (a) is a top view of object 11. Figure 3 (b) is a cross-sectional view showing the laser processing situation. Here, for the object 11, as an example, a circular line A is provided, concentric with the center 11c of the object 11 when viewed from the Z direction. Line A is the processing predetermined line indicating the processing performed by the irradiation of the laser L. Here, the object 11 is supported by the stage 2 in the direction opposite to the condenser lens 33 on the first surface 11a. That is, here, the first surface 11a is the incident surface of the laser L and the measuring laser LA.

[0060] The control unit 6 controls the displacement sensor 9 to acquire displacement information (displacement sensor voltage) representing the displacement of the first surface 11a. Additionally, the control unit 6 controls the laser irradiation unit 3 to irradiate the object 11 from the first surface 11a side with laser L. In this state, the control unit 6 controls the drive units 4 and 5 to move the focusing point C of the laser L relative to the object 11 along line A.

[0061] Subsequently, the control unit 6 controls the actuator 8 based on the displacement information, causing the focusing lens 33 to move along the Z direction, so that the focusing point C of the laser L is at a desired depth (Z-axis height) Ds from the first surface 11a. Thus, even if the first surface 11a is displaced in the Z direction, a modified region 12 is formed along line A at a certain depth Ds from the first surface 11a. In this way, tracking processing using the actuator 8 and the displacement sensor 9 can be performed in the laser processing apparatus 1.

[0062] [Explanation of the problem points]

[0063] Here, Figure 4 This is a diagram showing the relationship between the displacement sensor and the actuator. Figure 4 The vertical axis of (a) represents the displacement sensor voltage VD of displacement sensor 9. Figure 4 The horizontal axis of (a) represents the displacement (Z-axis height) of the first surface 11a of object 11 along the Z direction. Figure 4 (a) shows the displacement sensor voltage VD and the movable range RA of actuator 8.

[0064] like Figure 4 As shown, here, compared to the range of displacement sensor voltage VD that can change according to the displacement of the first surface 11a, i.e., the range of Z-axis height that the displacement of the first surface 11a can be measured by the displacement sensor 9, i.e., the length measurement range RD, the movable range RA of the actuator 8 is narrower. Therefore, as Figure 4 As shown in (b), the displacement of the first surface 11a of the object 11 becomes a portion of the displacement OD that exceeds the movable range RA of the actuator 8. Even if the displacement OD can be measured by the displacement sensor 9, it is not easy to perform tracking processing when laser processing is carried out along line A.

[0065] As an example, such as Figure 5 As shown in (a), this problem sometimes occurs when the object 11 is uniformly displaced on the first surface 11a in a manner that the object thickens from the center 11c toward the outer edge, i.e., when laser processing is performed along line A set on the relatively thick outer edge portion. The laser processing of such an object 11 will be described in detail.

[0066] Figure 6 This is a flowchart illustrating an example of a laser processing method. For example... Figure 5 , 6As shown, here, firstly, alignment is performed (step S11). More specifically, in step S11, for example, an image of the object 11 is acquired by photographing the object 11 with light transmitted through it. Then, based on initial information including a reference image of the object 11 that has been stored in advance and the acquired image, alignment is performed on the irradiation position of the laser L along the directions (X and Y directions) of the first surface 11a.

[0067] Next, the drive units 4 and 5 are driven, and the laser irradiation unit 3 moves relative to the object 1 in the X and Y directions, thereby moving the laser irradiation unit 3 at the center 11c of the object 11 (step S12). Furthermore, as follows, the laser irradiation unit 3 includes a displacement sensor 9. Therefore, moving the laser irradiation unit 3 means that the displacement sensor 9 also moves.

[0068] Next, at the center 11c of the object 11, the height is set, for example, using a marker (step S13). More specifically, in step S13, at the center 11c of the object 11, the drive units 4 and 5 are driven in such a way that the laser LA is focused onto the first surface 11a of the object 11, causing the entire laser irradiation unit 3 to move relative to the object 11 along the Z direction, and causing the focusing point of the laser LA to move relative to the object 11 along the Z direction. Then, the value of the displacement sensor voltage VD, i.e., the height setting voltage, is obtained when the focusing point of the laser LA coincides with the first surface 11a.

[0069] Next, a reference voltage for the drive voltage of actuator 8 is set (step S14). In step S14, the reference voltage of actuator 8 is associated with the height setting voltage obtained in step S13. More specifically, for example, when the displacement sensor voltage of displacement sensor 9 is the height setting voltage, the reference voltage is set in such a way that the reference voltage is applied to actuator 8 (i.e., the extension / retraction amount of actuator 8 is an amount corresponding to the reference voltage). Thus, for example, when displacement sensor voltage VD varies according to the displacement of the first surface 11a within a range including the height setting voltage, the extension / retraction amount of actuator 8 also varies around the amount corresponding to the reference voltage.

[0070] In the next step, the laser irradiation unit 3 moves in the X and Y directions by driving the drive units 4 and 5, and moves along line A (step S15). Then, processing is performed (step S16). In step S16, the focusing point C of the laser L moves relative to the object 11 along line A by driving the drive units 4 and 5. At this time, the displacement of the first surface 11a is measured by the displacement sensor 9. Then, the actuator 8 extends and retracts according to the displacement information (displacement sensor voltage VD) indicating the displacement of the first surface 11a measured by the displacement sensor 9, thereby moving the focusing lens 33 along the Z direction.

[0071] Figure 5 (b) is a graph showing an example of the relationship between the displacement sensor voltage VD and the Z-axis height AD of the condenser lens 33 (focus point C). Figure 5 The horizontal axis of (b) represents the movement distance of the focusing point C (laser irradiation part 3) in the X and Y directions. For example... Figure 5 As shown in (b), the displacement sensor voltage VD increases with the line A from the center 11c of the object 11 toward the outer edge (as the moving distance increases) due to the shape of the object 11.

[0072] The movable range RA of actuator 8 is a range centered on the center value Ao corresponding to the reference voltage. Therefore, the reference voltage is associated with a height setting voltage representing the displacement of the first surface 11a at the center 11c of object 11. As described above, object 11 has a shape where the thickness increases from the center 11c towards the outer edge. Therefore, the Z-axis height of the first surface 11a of object 11 is lowest at the center 11c, and thus, the height setting voltage becomes the lower limit of the displacement sensor voltage VD.

[0073] Therefore, actuator 8 is not driven below the center value Ao (e.g., the extended side) within the movable range RA, but only above the center value Ao (e.g., the contracted side) within the movable range RA. As a result, although actuator 8 is driven to adjust the Z-axis height AD of the focusing point C based on the change in displacement sensor voltage VD as the movement distance increases from the position Po corresponding to the center 11c to the distance Pa, after the distance Pa, the displacement sensor voltage VD exceeds the movable range RA of actuator 8, thus stopping actuator 8 and preventing adjustment of the Z-axis height AD of the focusing point C. That is, the aforementioned problem of difficulty in tracking processing may occur.

[0074] Next, other examples of processes that are not easy to track will be explained. Figure 7 (a) is a sectional view of object 11. Figure 7 (b) is a sectional view of object 11 unfolded along line A. In this example, although no sectional view is generated for the first face 11a of object 11. Figure 5 The uniform displacement shown in (a) is shown, but the displacement occurs along line A, that is, along the Z-axis height distribution of the first surface 11a of line A.

[0075] For this object 11, and Figure 6Similarly, in the laser processing method shown, a height is set at the center 11c of the object 11. When the actuator 8 is driven based on a reference voltage associated with the height setting voltage, after moving a distance to distance Pb and then to distance Pc, the actuator 8 is driven according to the change in the displacement sensor voltage VD to adjust the Z-axis height AD of the focusing point C. However, between distances Pb and Pc, since the displacement sensor voltage VD exceeds the movable range RA of the actuator 8, the actuator 8 stops, and the Z-axis height AD of the focusing point C is not adjusted. That is, the aforementioned problem of difficulty in tracking processing may also occur here.

[0076] As described above, regardless of how the displacement of the first surface 11a of the object 11 is uniformly set at the center 11c of the object 11, and when the actuator 8 is driven with a reference voltage corresponding to the voltage set at the center 11c, the range of tracking processing may become narrower.

[0077] [First Implementation Method]

[0078] In contrast, in this embodiment, the narrowing of the range that can be tracked for processing is suppressed. Next, a first embodiment of the laser processing apparatus and laser processing method will be described in detail. Here, object 11 and... Figure 7 The same as shown. Figure 8 This is a flowchart illustrating the laser processing method of the first embodiment.

[0079] like Figure 8 As shown, here, firstly, alignment is performed in the same manner as in step S11 (step S21). More specifically, in step S21, the control unit 6 controls an alignment camera (not shown) to capture an image of the object 11 by photographing the object 11 with light transmitted through it. Then, based on initial information including a reference image of the object 11 stored in a memory or the like in the control unit 6 and the acquired image, alignment is performed on the irradiation position of the laser L along the directions (X and Y directions) of the first surface 11a.

[0080] Next, by tracking line A (step S22, acquisition step), displacement information representing the displacement of the first surface 11a of the object 11 is acquired (step S23, acquisition step). Steps S22 and S23 will be explained in detail. In steps S22 and S23, firstly, the control unit 6 controls the drive units 4 and 5 to move the laser irradiation unit 3 along the X and Y directions, positioning the laser irradiation unit 3 on line A. Furthermore, as described above, here, the displacement sensor 9 moves integrally with the laser irradiation unit 3. Therefore, moving the laser irradiation unit 3 means moving the displacement sensor 9.

[0081] Next, in processes S22 and S23, the control unit 6, while controlling the drive units 4 and 5 to move the laser irradiation unit 3 relative to line A, simultaneously controls the displacement sensor 9 to irradiate the object 11 with the measuring laser LA (for tracking). As a result, the control unit 6 acquires the displacement sensor voltage VD output from the displacement sensor 9 based on the reflected light LR of the measuring laser LA, as displacement information representing the displacement of the first surface 11a of the object 11. In other words, the control unit 6 performs a process to acquire displacement information representing the displacement of the first surface 11a in the Z direction.

[0082] As a result, displacement information of the first surface 11a of the object 11 along line A is obtained. That is, here, the control unit 6 continuously measures the displacement of the first surface 11a by means of the displacement sensor 9 and obtains displacement information. Thus, the control unit 6 obtains the distribution of the displacement of the first surface 11a along line A. Therefore, according to the control unit 6, the height setting can be selected at which position of the first surface 11a where the displacement changes along line A.

[0083] In the next step, the control unit 6 controls the drive units 4 and 5 to move the laser irradiation unit 3 in the X and Y directions based on the displacement information, thereby positioning the laser irradiation unit 3 at a first position where the displacement of the first surface 11a is the center value of the range of the displacement of the first surface 11a (step S24). Furthermore, the first position is a position within the XY plane that includes both the X and Y directions.

[0084] Next, similar to step S13, a height setting is performed at the first position (step S25). More specifically, in step S25, with the laser irradiation unit 3 positioned at the first position, the control unit 6 drives the drive units 4 and 5 to focus the measuring laser LA onto the first surface 11a of the object 11, causing the laser irradiation unit 3 to move relative to it along the Z direction, and causing the focusing point of the measuring laser LA to move relative to the object 11 along the Z direction. Then, the control unit 6 acquires the value of the displacement sensor voltage VD, i.e., the height setting voltage, when the focusing point of the measuring laser LA coincides with the first surface 11a.

[0085] Next, similar to step S14, a reference voltage for the drive voltage of the actuator 8 is set (step S26). In step S26, the control unit 6 associates the reference voltage of the actuator 8 with the height setting voltage obtained in step S25. More specifically, for example, when the displacement sensor voltage VD of the displacement sensor 9 is the height setting voltage, the reference voltage is set in such a way that a reference voltage is applied to the actuator 8 (i.e., the extension or retraction of the actuator 8 is an amount corresponding to the reference voltage).

[0086] Therefore, as Figure 9As shown, the movable range RA of the actuator 8 is set with the displacement of the first surface 11a at the first position Pe (the center value of the Z-axis height and displacement) as the center value Ao. Therefore, when the actuator 8 is tracking machining, it is driven on both the lower side (e.g., the extended side) and the upper side (e.g., the retracted side) of the center value Ao in the movable range RA, reducing the range in which the actuator 8 stops and tracking machining is difficult (in this case, 0).

[0087] Furthermore, in the above steps S24 to S26, the first position for height setting is designated as the position where the displacement of the first surface 11a is the center value of the range of displacement of the first surface 11a. However, the first position may not be the center value position, but may be a position that is a specific value of the range that includes a part of the center value of the displacement of the first surface 11a, i.e., the center range. However, the center range here is at least the range excluding the upper and lower limits of the displacement of the first surface 11a.

[0088] Therefore, in steps S24 to S26, the control unit 6 performs an association process that associates a specific value (here, a voltage value is set at the height of the first position where the specific value is set) of a range containing the center value of the displacement with the reference voltage of the driving voltage of the actuator 8, based on displacement information. Furthermore, in the laser processing method of this embodiment, steps S24 to S26 perform an association process that associates a specific value (here, a voltage value is set at the height of the first position where the specific value is set) of a range containing the center value of the displacement with the reference voltage of the driving voltage of the actuator 8, based on displacement information. The above example uses a specific value as the center value.

[0089] In addition, the processes S24 to S26, which are repeated by the control unit 6 and above, are performed as associated processes, and the following processes are executed: First process, by controlling the drive units 4 and 5, the laser irradiation unit 3 is moved to a first position where the displacement of the first surface 11a is within the center range; Second process, after the first process, by controlling the drive units 4 and 5, the laser irradiation unit 3 is moved relative to the first surface 11a in the Z direction in a manner that the laser LA is focused onto the first surface 11a; Third process, after the second process, the measured value of the displacement sensor 9 (height setting voltage) when the laser LA is focused onto the first surface 11a is associated with the reference voltage of the actuator 8.

[0090] In the next step, the laser irradiation unit 3 is moved along line A (step S27). More specifically, in step S27, the control unit 6 controls the drive units 4 and 5 to move the laser irradiation unit 3 along the X and Y directions, thereby positioning the laser irradiation unit 3 on line A.

[0091] Next, laser processing is actually performed (step S28, processing step). That is, the control unit 6 drives the actuator 8 with a reference voltage as the center, adjusts the position of the focusing point C of the laser L in the Z direction according to the displacement of the first surface 11a, and moves the focusing point C relative to the line A in the X direction, performing laser processing on the object 11 along the line A. At this time, the control unit 6 can drive the actuator 8 according to the displacement at the processing position based on the acquired displacement information and the processing position on the line A.

[0092] As explained above, in the laser processing apparatus 1 and laser processing method of this embodiment, firstly, displacement information representing the displacement of the first surface 11a of the object 11 in the Z direction is acquired. Then, based on the acquired displacement information, a specific value of the range containing a portion of the center value of the displacement of the first surface 11a of the object 11 (i.e., the center range) is associated with a reference voltage for the drive voltage of the actuator 8. Then, by driving the actuator 8 around this reference voltage, while adjusting the position of the focusing point C of the laser L in the Z direction according to the displacement of the first surface 11a of the object 11, the focusing point C is moved relative to the line A along the X direction, and laser processing (tracking processing) of the object 11 is performed along line A. Therefore, during tracking processing, at least the use of only the lower or upper side of the center of the movable range of the actuator 8 is avoided. Therefore, compared to the case where the displacement amount (Z-axis height) of the first surface 11a at the center of the object 11 is always associated with the reference voltage of the actuator 8, the narrowing of the range for tracking processing can be suppressed.

[0093] Furthermore, in the laser processing apparatus 1 and laser processing method of this embodiment, the specific value can also be the center value of the displacement of the first surface 11a. In this case, during tracking processing, the lower and upper sides of the center of the movable range RA of the actuator 8 are used equally. Therefore, the narrowing of the tracking processing range is reliably suppressed.

[0094] Furthermore, the laser processing apparatus 1 of this embodiment includes a displacement sensor 9 that is integrally movable with the laser irradiation unit 3, and is used to measure the displacement of the first surface 11a by emitting a measuring laser LA toward the object 11 and inputting the reflected light LR of the measuring laser LA. Therefore, displacement information representing the displacement of the first surface 11a of the object 11 can be obtained using the displacement sensor 9.

[0095] Furthermore, in the laser processing apparatus 1 of this embodiment, the control unit 6 continuously measures the displacement of the first surface 11a using the displacement sensor 9 to obtain displacement information. Therefore, displacement information that is more consistent with the actual displacement of the first surface 11a of the object 11 can be obtained.

[0096] Furthermore, the laser processing apparatus 1 of this embodiment includes drive units 4 and 5 for moving the laser irradiation unit 3 and the displacement sensor 9 relative to the object 11 along the Z direction. Therefore, the control unit 6 performs the following processes in the association process: a first process, whereby, under the control of the drive units 4 and 5, the laser irradiation unit 3 and the displacement sensor 9 are moved to a first position where the displacement of the first surface 11a becomes a specific value; a second process, after the first process, whereby, under the control of the drive units 4 and 5, the laser irradiation unit 3 and the displacement sensor 9 are moved relative to each other along the Z direction in a manner that the laser LA is focused onto the first surface 11a; and a third process, after the second process, whereby the measured value (height setting voltage value) of the displacement sensor 9 when the laser LA is focused onto the first surface 11a is associated with a reference voltage. Thus, in the association process, the actual measured value of the displacement of the first surface 11a of the object 11 can be used as a specific value and associated with the reference voltage of the drive voltage of the actuator 8.

[0097] [Second Implementation]

[0098] Next, a second embodiment of the laser processing apparatus and laser processing method will be described. Here, the thickness of the object 11 is as follows: Figure 10 As shown in (a), the central portion containing the center 11c is fixed, and it gradually decreases from the central portion toward the outer edge at a certain ratio. That is, the displacement (Z-axis height) of the first surface 11a of the object 11 is fixed in the central portion, and gradually decreases from the central portion toward the outer edge. In addition, line A is set in a straight line in a manner that passes through the central portion from one outer edge to the outer edge of the other.

[0099] For such an object 11, a height setting voltage is sometimes obtained by setting the height at the center 11c, and this height setting voltage is associated with the reference voltage of the actuator 8. In this case, the center value Ao of the movable range RA of the actuator 8 is set as the upper limit of the displacement of the first surface 11a. Therefore, in this case, if tracking machining is performed along line A, the actuator 8 is only driven on the lower side (e.g., the extended side) of the center value Ao of the movable range RA, for example, in the range from the outer edge of one side of the object 11 to the distance Pf and from the distance Pg to the outer edge of the other side of the object 11. The displacement sensor voltage VD exceeds the movable range RA of the actuator 8, making tracking machining difficult.

[0100] In contrast, in this embodiment, the tracking process is performed as follows. Figure 11 This is a flowchart illustrating the laser processing method according to the second embodiment. For example... Figure 11As shown, in the laser processing method of this embodiment, firstly, the control unit 6 acquires displacement information representing the displacement of the first surface 11a of the object 11 (step S31). Similar to the first embodiment, the control unit 6 can also acquire displacement information by tracking; however, here, the shape of the object 11 is known, and displacement information is acquired through external input.

[0101] Next, alignment is performed in the same manner as in step S21 (step S32). Then, the laser irradiation unit 3 is moved to the center 11c of the object 11 (step S33). More specifically, in step S33, the control unit 6 controls the drive units 4 and 5 to move the laser irradiation unit 3 relative to the object 11 along the X and Y directions, thereby moving the laser irradiation unit 3 to the center 11c of the object 11. As described above, the center 11c of the object 11 is the second position where the displacement of the first surface 11a reaches its upper limit.

[0102] Next, similar to step S25, height setting is performed at the second position (step S34). More specifically, in step S34, with the laser irradiation unit 3 positioned at the second position, the control unit 6 drives the drive units 4 and 5 to focus the measuring laser LA onto the first surface 11a of the object 11, causing the laser irradiation unit 3 to move relative to the object 11 along the Z direction, and causing the focusing point of the measuring laser LA to move relative to the object 11 along the Z direction. Then, the control unit 6 acquires the value of the displacement sensor voltage VD, i.e., the height setting voltage, when the focusing point of the measuring laser LA coincides with the first surface 11a.

[0103] Next, the reference voltage for the drive voltage of the actuator 8 is set in the same manner as in step S26 (step S35). That is, in step S35, the control unit 6 associates the reference voltage of the actuator 8 with the height setting voltage obtained in step S34. As a result, the actuator 8 is driven with the upper limit value of the displacement of the first surface 11a as the center. Therefore, in the next step, the control unit 6 performs offset of the movable range RA (step S36).

[0104] More specifically, in step S36, the control unit 6 controls the drive units 4 and 5 to move the laser irradiation unit 3 relative to each other along the Z direction. Here, the control unit 6 moves the laser irradiation unit 3 relative to each other along the Z direction by moving the focusing point of the measuring laser LA to a side closer to the second surface 11b than the first surface 11a. In this state, the control unit 6 acquires the displacement sensor voltage VD. This displacement sensor voltage VD is as follows... Figure 12 As shown, the offset value Ve is the downward offset of the height setting voltage Vo obtained in process S34.

[0105] Then, the control unit 6 associates the offset value Ve with the reference voltage value of the actuator 8. That is, when the displacement sensor voltage VD of the displacement sensor 9 is the offset value Ve, the reference voltage is set in such a way that the actuator 8 is given a reference voltage (i.e., the extension or retraction of the actuator 8 is an amount corresponding to the reference voltage). The offset value Ve is a value corresponding to the center value of the displacement of the first surface 11a of the object 11, for example, it is half the value of the height setting voltage Vo.

[0106] Thus, the control unit 6 performs an association process in steps S34 to S36, which involves associating a specific value (in this case, the offset value Ve of the height setting voltage Vo) of a range containing the center value of the displacement of the first surface 11a with a reference voltage of the driving voltage of the actuator 8, based on displacement information. Furthermore, in the laser processing method of this embodiment, the association process, which involves associating a specific value of the center value of the displacement containing the center value with a reference voltage of the driving voltage of the actuator 8, is performed in steps S34 to S36. The example described above uses a specific value as the center value.

[0107] In addition, the processes S34 to S36, which are repeated by the control unit 6 and above, are performed as associated processes, and the following processes are executed: Fourth process, by controlling the drive units 4 and 5, the laser irradiation unit 3 is moved to a second position where the displacement of the first surface 11a is the upper limit value; Fifth process, after the fourth process, by controlling the drive units 4 and 5, the laser irradiation unit 3 is moved relative to the first surface 11a in the Z direction at the second position in a manner that the laser LA is focused onto the first surface 11a; Sixth process, after the fifth process, the offset is set in a manner that the offset value (the value of the displacement corresponding to the offset value Ve) is included in the center range by adding the measured value of the displacement sensor 9 (height setting voltage Vo) when the laser LA is focused onto the first surface 11a, and the offset value Ve is used as a specific value and associated with the reference voltage.

[0108] Therefore, as Figure 12 As shown, the movable range RA of actuator 8 is offset. Therefore, when actuator 8 is performing tracking processing along line A, it is driven on both the lower side (e.g., the extended side) and the upper side (e.g., the contracted side) of the center value Ao in the movable range RA, reducing the range (in this case, 0) where actuator 8 stops and tracking processing is difficult.

[0109] In the next step, the control unit 6 moves the laser irradiation unit 3 along line A in the same manner as in step S27 (step S37). Then, laser processing is actually performed in the same manner as in step S28 (step S38, processing step). That is, the control unit 6 performs laser processing on the object 11 by driving the actuator 8 with a reference voltage as the center, adjusting the position of the focusing point C of the laser L in the Z direction according to the displacement of the first surface 11a, and moving the focusing point C relative to line A in the X direction. At this time, the control unit 6 can drive the actuator 8 based on the acquired displacement information and the processing position on line A, according to the displacement at that processing position.

[0110] As explained above, in this embodiment, the narrowing of the range for tracking processing can be suppressed in the same way as in the first embodiment. Furthermore, in this embodiment, during the association processing, an offset value (the value corresponding to the offset value Ve) that deviates from the actual measured value (height setting voltage Vo) of the displacement of the first surface 11a of the object 11 can be used as a specific value and associated with the reference voltage of the drive voltage of the actuator 8.

[0111] Furthermore, in the example above, the second position where the height is set is designated as the position where the displacement of the first surface 11a reaches its upper limit. However, the second position can also be designated as the position where the displacement of the first surface 11a reaches its lower limit, depending on the shape of the object 11 and the setting of the displacement reference.

[0112] Furthermore, when the displacement sensor 9 and the laser L are coaxially configured, the change of the displacement sensor voltage VD relative to the Z-axis height of the first surface 11a is sometimes non-linear. The above-described process S36 is an example of a case where the displacement sensor voltage VD is non-linear. In contrast, when the displacement sensor 9 and the laser L are not coaxially configured, i.e., when the change of the displacement sensor voltage VD relative to the Z-axis height is linear, the characteristics of the displacement sensor voltage VD relative to the Z-axis height are known. In this case, in process S36, the offset value Ve can be calculated based on the known characteristics of the displacement sensor voltage VD without actually moving the laser irradiation unit 3 in the Z direction.

[0113] [Third Implementation Method]

[0114] Next, a third embodiment of the laser processing apparatus and laser processing method will be described. Figure 13 This is a flowchart illustrating the laser processing method according to the third embodiment. Furthermore, here, multiple lines A are provided on straight lines that extend parallel to each other when viewed from the Z direction, relative to the object 11.

[0115] like Figure 13As shown, steps S41 to S48 are performed in the same manner as in the first embodiment. The contents of steps S41 to S48 are the same as those of steps S21 to S28. However, in step S42, displacement information of the first surface 11a of the object 11 along the line A is obtained by tracking one of the multiple lines A in the same manner as in step S22 (step S43). In addition, in step S45, the height is set based on the displacement information on the line A in the same manner as in step S25, and the reference voltage is set in step S46 in the same manner as in step S26. Then, in step S47, the laser irradiation unit 3 is moved along the line A in the same manner as in step S27, and in step S48, laser processing is performed on the line A in the same manner as in step S28.

[0116] Next, the control unit 6 determines whether the line A (the line A that was just processed) is the last line A among multiple lines A (step S49). If the result of step S49 is that the line A is the last line A (step S49: Yes), the process ends. On the other hand, if the result of step S49 is that the line A is not the last line A (step S49: No), the control unit 6 controls the drive units 4 and 5 to move the laser irradiation unit 3 relative to each other in the X and Y directions, so that the laser irradiation unit 3 moves to another line A (step S50).

[0117] Then, returning to step S42, the other line A is treated as the object, and the subsequent steps of step S42 are performed again. Thus, in this embodiment, for each of the multiple lines A, the height is set and the reference voltage is set. Therefore, in addition to the same effect as in the first embodiment, more suitable tracking processing of the displacement of the object 11 along the first surface 11a of each line A can be performed.

[0118] [Fourth Implementation Method]

[0119] In contrast, Figure 14 In the fourth embodiment shown, if the result of step S49 is that line A is not the last line A (step S49: No), the control unit 6 controls the drive units 4 and 5 to move the laser irradiation unit 3 relatively in the X and Y directions, moving the laser irradiation unit 3 to another line A (step S50). Then, it returns to step S48, and step S48 is performed again with that other line A as the target. That is, in this embodiment, the displacement information, height setting voltage, and reference voltage obtained during the tracking of one line A are used to perform tracking processing on other lines A. Therefore, according to this embodiment, in addition to having the same effects as the first embodiment, the time required for obtaining displacement information and height setting voltage, and for setting the reference voltage, can be shortened.

[0120] [Fifth Implementation]

[0121] Next, the laser processing apparatus and laser processing method of the fifth embodiment will be described. Figure 15 This is a flowchart illustrating the laser processing method according to the fifth embodiment. (Example) Figure 15 As shown, steps S61 to S63 are performed in the same manner as in the first embodiment. The contents of steps S61 to S63 are the same as those of steps S21 to S23.

[0122] Next, a determination is made as to whether the displacement of the first surface 11a of the object 11 exceeds the movable range RA of the actuator 8 (step S64). More specifically, in step S64, the control unit 6 performs a determination process based on a comparison between displacement information (displacement sensor voltage VD) and the movable range RA of the actuator 8 to determine whether the movable range RA of the actuator 8 exceeds the displacement.

[0123] Then, if the result of step S64 is that the displacement of the first surface 11a of the object 11 exceeds the movable range RA of the actuator 8 (step S64: No), the control unit 6 performs notification processing to notify the message (step S70). As an example of notification, the control unit 6 can display a warning on the input receiving unit. After that, the processing ends. On the other hand, if the result of step S64 is that the displacement does not exceed the movable range RA (step S64: Yes), steps S65 to S69 are performed. Steps S65 to S69 are the same as steps S24 to S28 in the first embodiment. Thus, according to this embodiment, in addition to the same effect as the first embodiment, it is also possible to identify the case where the displacement of the first surface 11a of the object 11 exceeds the movable range RA of the actuator 8.

[0124] [Sixth Implementation Method]

[0125] Next, the laser processing apparatus and laser processing method of the sixth embodiment will be described. This embodiment is as follows... Figure 16 The example shown corresponds to a situation where the displacement (displacement sensor voltage VD) of the first surface 11a of the object 11 significantly exceeds the movable range RA of the actuator 8. In this embodiment, as... Figure 17 As shown, steps S71 to S74 are performed. Steps S71 to S74 are the same as steps S61 to S64 in the fifth embodiment. Therefore, if the result of step S74 is that the displacement of the first surface 11a of the object 11 does not exceed the movable range RA of the actuator 8, steps S75 to S79 ​​are performed in the same way as steps S24 to S28 in the first embodiment.

[0126] On the other hand, if the result of process S74 is that the displacement of the first surface 11a of the object 11 exceeds the movable range RA of the actuator 8 (process S74: No), then... Figure 18 As shown, the lower limit region is extracted at the position where the displacement of the first surface 11a in line A reaches the lower limit value, that is, the position where the displacement sensor voltage VD and the Z-axis height of the first surface 11a reach the lower limit value (process S81). Here, the control unit 6 is as follows Figure 16 As shown, the region that is part of line A containing the displacement within the movable range RA when the displacement sensor voltage VD reaches its lower limit value at position Pm and the Z-axis height of the first surface 11a at position Pm is taken as the lower limit value of the movable range RA is defined as the lower limit region. Here, the lower limit region extends to position Ph in line A.

[0127] Next, the control unit 6 sets the extracted lower limit region as the object and performs height setting, reference voltage setting, and tracking processing in processes S82 to S85. The specific content of these processes S82 to S85 is the same as processes S25 to S28 in the first embodiment, except that the object is not the entire line A but the lower limit region. As an example, in process S82, within this lower limit region, the height is set at a first position where the displacement of the first surface 11a is the center value of the range of displacement of the first surface 11a. As described above, only this lower limit region in line A is processed.

[0128] Next, as Figure 19 As shown, other lower limit regions are extracted from the unprocessed area of ​​line A (step S86). Specifically, in step S86, the control unit 6 extracts other lower limit regions including the positions where the displacement of the first surface 11a in the unprocessed area of ​​line A reaches a lower limit value, i.e., the positions where the displacement sensor voltage VD and the Z-axis height of the first surface 11a reach a lower limit value. Here, the control unit 6... Figure 16 As shown, the region remaining of line A, which contains the displacement sensor voltage VD in the unprocessed area at position Ph and where the Z-axis height of the first surface 11a at position Ph is set to the lower limit of the movable range RA, is used as the other lower limit region. Here, this other lower limit region is the region after position Ph in line A.

[0129] Next, the control unit 6 treats the extracted other lower limit regions as objects and performs height setting, reference voltage setting, and tracking processing in processes S87 to S89. The specific content of these processes S87 to S89 is the same as processes S25 to S28 of the first embodiment, except that the object is not the entire line A but other lower limit regions. As an example, in process S86, within these other lower limit regions, a height setting is performed at a first position where the displacement of the first surface 11a is the center value of the range of displacement of the first surface 11a. As described above, these other lower limit regions in line A are further processed.

[0130] Afterwards, control unit 6 determines whether the processing of all areas of line A (i.e., the entirety of line A) is complete (process S90). If the result of process S90 is that the processing of all areas of line A is complete (process S90: Yes), the process ends. On the other hand, if the result of process S90 is that the processing of all areas of line A is not complete (process S90: No), the processes after process S86 are repeated.

[0131] As described above, in this embodiment, a line A is divided into multiple regions encompassed by the movable range RA of the actuator 8 for tracking processing. Specifically, in this embodiment, if the result of the determination (determination processing) in step S74 is that the displacement of the first surface 11a exceeds the movable range RA of the actuator 8, the control unit 6 divides line A into multiple parts (multiple lower limit regions) such that the displacement of the first surface 11a is contained within the movable range RA, and performs association processing and processing on each part. Therefore, according to this embodiment, the range of areas capable of tracking processing is expanded (in the example above, tracking processing can be performed in all regions of the first surface 11a).

[0132] [Variation Example]

[0133] The above embodiments illustrate one aspect of the present invention. Therefore, the present invention is not limited to the above embodiments and can be modified in any way.

[0134] For example, in the above embodiment, an example is given where the control unit 6 continuously measures the displacement of the first surface 11a via the displacement sensor 9 in order to obtain displacement information (displacement sensor voltage VD). However, as... Figure 20 As shown in (a), the control unit 6 can also acquire displacement information by discretely measuring the displacement at multiple locations K within the first surface 11a of the object 11 using the displacement sensor 9. In this case, the control unit 6 can correlate the center value of the displacement of each of the multiple locations K (and the voltage VD of each displacement sensor corresponding to the displacement) with the reference voltage of the actuator 8.

[0135] In addition, control unit 6, etc. Figure 20As shown in (b), regardless of the shape of line A, displacement information can also be obtained by using displacement sensor 9 to measure the displacement of the first surface 11a in a spiral pattern. In this case, based on the obtained displacement information, the central value of the displacement (and the displacement sensor voltage VD corresponding to the displacement) can be correlated with the reference voltage of actuator 8.

[0136] Additionally, in the examples above, such as Figure 21 As shown in (a), the position corresponding to the reference voltage associated with the height setting voltage within the movable range RA of the actuator 8 is taken as the center value Ao. That is, the extension or retraction of the actuator 8 when the reference voltage equivalent to the height setting voltage is applied to the actuator 8 is the center value Ao of the movable range RA. In this case, the range Rc from the center value Ao to the lower limit value Ac of the movable range RA and the range Re from the center value Ao to the upper limit value Ae of the movable range RA become equal.

[0137] However, as Figure 21 As shown in (b), the value A1, which is offset from the center value Ao of the movable range RA of the actuator 8 to the upper limit value Ae (or lower limit value Ac) of the movable range RA, can also be associated with the reference voltage. In this case, the range Rc is wider (or narrower) than the range Re. In this case, after the association process, the control unit 6 drives the actuator 8 within the movable range RA containing the reference voltage, adjusts the position of the focusing point C of the laser L in the Z direction according to the displacement of the first surface 11a, and moves the focusing point C relative to the line A in the X direction, performing laser processing of the object 11 along the line A. Thus, in this case, the reference voltage is offset relative to the center of the movable range RA.

[0138] Furthermore, the first to sixth embodiments described above can be combined arbitrarily. For example, in the third and fourth embodiments, examples are given of performing tracking processing across multiple straight lines A provided relative to the object 11. In contrast, for example, in the first embodiment, multiple circular lines A can also be provided relative to the object 11, and the processes of the third and fourth embodiments can be applied in a manner that tracks and processes across multiple circular lines A.

Claims

1. A laser processing apparatus, wherein provided are: a support section for supporting an object including a first face and a second face on an opposite side of the first face; a laser irradiation section for irradiating the object supported by the support section with laser light from the first face side via a condensing lens; an actuator for driving the condensing lens in a Z direction from the second face toward the first face; a first movement section for moving at least one of the support section and the laser irradiation section to relatively move a condensing point of the laser light with respect to the object in an X direction intersecting the Z direction; a control section that controls at least the actuator, the laser irradiation section, and the first movement section, and performs laser processing of the object by irradiating the object with the laser light, the control section performs the following processing: an acquisition process that acquires displacement information indicating displacement of the first face with respect to the Z direction; an association process that, after the acquisition process, associates a specific value of a center range that is a range of a portion of the displacement including a center value of the displacement, and a reference voltage of a drive voltage of the actuator, based on the displacement information; a processing process that, after the association process, drives the actuator with the reference voltage as a center, whereby the position of the condensing point of the laser light with respect to the Z direction is adjusted according to the displacement, and the condensing point is relatively moved along a line in the X direction, and laser processing of the object is performed along the line, the control section performs a determination process that determines whether the displacement exceeds a movable range of the actuator, between the acquisition process and the association process, the control section, in a case where the result of the determination process is that the displacement exceeds the movable range, divides the line into a plurality of portions in a manner that the displacement is included in the movable range, and performs the association process and the processing process for each portion.

2. The laser processing apparatus according to claim 1, wherein the specific value is a center value of the displacement.

3. The laser processing apparatus according to claim 1, wherein provided is a displacement sensor that is provided so as to move integrally with the laser irradiation section, that emits measurement light toward the object, and that inputs reflected light of the measurement light, and that measures displacement of the first face and acquires the displacement information.

4. The laser processing apparatus according to claim 2, wherein provided is a displacement sensor that is provided so as to move integrally with the laser irradiation section, that emits measurement light toward the object, and that inputs reflected light of the measurement light, and that measures displacement of the first face and acquires the displacement information.

5. The laser processing apparatus according to claim 3, wherein the control section continuously measures the displacement and acquires the displacement information by the displacement sensor.

6. The laser processing apparatus according to claim 4, wherein the control section continuously measures the displacement and acquires the displacement information by the displacement sensor.

7. The laser processing apparatus according to claim 3, wherein The control section discretely measures the displacement at a plurality of points on the first surface and acquires the displacement information by the displacement sensor.

8. The laser processing apparatus according to claim 4, wherein The control section discretely measures the displacement at a plurality of points on the first surface and acquires the displacement information by the displacement sensor.

9. The laser processing apparatus according to any one of claims 3 to 8, wherein a second moving section for relatively moving the laser irradiation section and the displacement sensor along the Z direction with respect to the object, The control section performs the following processing in the correlation processing: a first processing of moving the laser irradiation section and the displacement sensor to a first position where the displacement of the first surface is the specific value by control of the first moving section; a second processing of relatively moving the laser irradiation section and the displacement sensor along the Z direction in a manner that the measurement light is condensed to the first surface by control of the second moving section after the first processing; a third processing of correlating a measured value of the displacement of the displacement sensor when the measurement light is condensed to the first surface with the reference voltage after the second processing.

10. The laser processing apparatus according to any one of claims 3 to 8, wherein a second moving section for relatively moving the laser irradiation section and the displacement sensor along the Z direction with respect to the object, The control section performs the following processing in the correlation processing: a fourth processing of moving the laser irradiation section and the displacement sensor to a second position where the displacement of the first surface is a lower limit value or an upper limit value by control of the first moving section; a fifth processing of relatively moving the laser irradiation section and the displacement sensor along the Z direction in a manner that the measurement light is condensed to the first surface by control of the second moving section after the fourth processing; a sixth processing of setting an offset amount in a manner that an offset value of the offset amount added to a measured value of the displacement of the displacement sensor when the measurement light is condensed to the first surface is included in the center range, and correlating the offset value as the specific value with the reference voltage after the fifth processing.

11. The laser processing apparatus according to any one of claims 1 to 8, wherein The control section performs a notification processing of notifying that the displacement exceeds the movable range in a case where the result of the determination processing is that the displacement exceeds the movable range, between the acquisition processing and the correlation processing. The control section performs the correlation processing and the processing processing in a case where the result of the determination processing is that the displacement does not exceed the movable range.

12. The laser processing apparatus according to claim 9, wherein The control section performs a notification processing of notifying that the displacement exceeds the movable range in a case where the result of the determination processing is that the displacement exceeds the movable range, between the acquisition processing and the correlation processing. The control section executes the correlation process and the processing process when the result of the determination process is that the displacement does not exceed the movable range.

13. The laser processing apparatus according to claim 10, wherein The control section executes a notification process of notifying that the displacement exceeds the movable range when the result of the determination process is that the displacement exceeds the movable range, between the acquisition process and the correlation process. The control section executes the correlation process and the processing process when the result of the determination process is that the displacement does not exceed the movable range.

14. A laser processing method, wherein is a laser processing method in which laser processing is performed by controlling at least a laser irradiation section, an actuator, and a first movement section, the laser irradiation section is for irradiating laser light from the first face side via a condensing lens with respect to an object which includes a first face and a second face on the opposite side of the first face and which is supported by a support section, the actuator is for driving the condensing lens in a Z direction which is a direction from the second face toward the first face, the first movement section is for moving at least one of the support section and the laser irradiation section so that a condensing point of the laser light relatively moves with respect to the object in an X direction which is a direction intersecting the Z direction, the laser processing method includes the following processes: an acquisition process of acquiring displacement information indicating a displacement of the first face with respect to the Z direction; a correlation process of correlating, after the acquisition process, a specific value of a center range which is a range of a portion of the displacement including a center value of the displacement and a reference voltage of a drive voltage of the actuator; a processing process of driving the actuator with the reference voltage as a center, after the correlation process, whereby the laser processing of the object is performed along a line in the X direction while adjusting a position of a condensing point of the laser light with respect to the Z direction according to the displacement and relatively moving the condensing point along the line, determining whether the displacement exceeds a movable range of the actuator between the acquisition process and the correlation process, when the result of the determination is that the displacement exceeds the movable range, dividing the line into a plurality of portions in a manner that the displacement is included in the movable range, and executing the correlation process and the processing process with respect to each of the portions.

Images