Object processing method

Abstract

To provide an object processing method capable of suppressing quality deterioration of a processed object.SOLUTION: An object processing method includes a laser processing step of forming a modified region 12 along a virtual surface M inside of an object 11 by irradiating the object 11 with a laser beam L. The object 11 includes a front face 11a, and a part at the side of the front face 11a is defined as a removal region 11Z. The virtual surface M includes a first face M11 and a second face M12 which is connected to the side of a rear face 11b in the first face 11 via a connection part J and extends in a direction crossing the first face M11. In a cross-sectional view in a Z direction, a first angle θ1 formed from the first face M11 and the second face M12 and a second angle θ2 formed from the front face 11a and the second face M12 are obtuse angles, the first angle θ1 is smaller than the second angle θ2, and the connection part J is provided in the removal region 11Z.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to an object processing method.

Background Art

[0002] As an object processing method for processing an object, there is known a method including a laser processing step of forming a modified region along a virtual surface inside the object by irradiating the object with a laser beam (see, for example, Patent Document 1). After the laser processing step, a part of the object is peeled off with the modified region extending across the virtual surface as a boundary. In such an object processing method, a part on the surface side of the object is defined as a removal region that is removed by, for example, grinding or the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described technology, for example, when a part of the object is peeled off with the modified region extending across the virtual surface as a boundary, a part of the object may remain as a remaining part on the peeled surface (the surface corresponding to the virtual surface after peeling). As a result, the remaining part may have an adverse effect on the quality of the processed object, and there is a possibility that the quality of the processed object deteriorates.

[0005] Therefore, an object of the present disclosure is to provide an object processing method capable of suppressing deterioration in the quality of the processed object.

Means for Solving the Problems

[0006] The object processing method according to the present disclosure is "[1] An object processing method for processing an object, comprising a laser processing step of forming a modified region along a virtual surface inside the object by irradiating the object with laser light, the object having a surface, a part of the surface side being a removal region, the virtual surface including a first surface extending in a direction intersecting the surface, and a second surface connected to the opposite side of the surface side in the first surface via a connection portion and extending in a direction intersecting the first surface, in a cross-sectional view intersecting the surface, a first angle formed by the first surface and the second surface, and a second angle formed by the surface and the second surface are obtuse angles, the first angle being smaller than the second angle, and the connection portion being provided in the removal region of the object, object processing method".

[0007] In the object processing method according to the present disclosure, by defining the first and second angles in this way, for example, when a part of the object is peeled off with the modified region extending across the virtual surface as a boundary, a remaining part (hereinafter, also simply referred to as "remaining part"), which is a part of the object that could not be completely peeled off, is likely to be concentrated around a location corresponding to the connection portion between the first surface and the second surface of the virtual surface on the peeling surface. And since the connection portion is provided in the removal region, when the removal region is removed, the remaining part will also be removed together, so it is possible to suppress the remaining part from having an adverse effect on the quality of the processed object. Therefore, according to the present disclosure, it is possible to suppress the deterioration of the quality of the processed object.

[0008] The object processing method according to the present disclosure may be "[2] The object processing method according to [1] above, comprising a peeling step of peeling off a part of the object with the modified region extending across the virtual surface as a boundary after the laser processing step, and a removal step of removing the removal region of the object after the laser processing step." In this case, it is possible to perform peeling of a part of the object and removal of the removal region.

[0009] The object processing method according to the present disclosure may be "[3] The removal step is the object processing method described in [2] above, which removes by grinding the removal region." In this case, the removal step can be specifically realized.

[0010] The object processing method according to the present disclosure may be "[4] The virtual surface includes a third surface that is connected to the opposite side of the second surface from the surface side and extends in a direction intersecting the second surface. In a cross-sectional view intersecting the surface, the third angle formed by the second surface and the third surface is an obtuse angle, and the first angle is smaller than the third angle. The object processing method according to any one of [1] to [3] above." Also in this case, for example, when a part of the object is peeled off with the modified region across the virtual surface as a boundary, it is possible to intensively leave the remaining part easily around the location corresponding to the connection part on the peeling surface. Further, it becomes easy to adjust the position of the first surface in the object according to the user's request without changing the first angle.

[0011] The object processing method according to the present disclosure may be "[5] The object includes a peripheral portion located at the periphery and a main body portion inside the peripheral portion when viewed from the direction facing the surface, and the first surface is formed inside the object along the boundary between the peripheral portion and the main body portion in the object. The object processing method according to any one of [1] to [4] above." In this case, it becomes possible to peel off at least a part of the peripheral portion.

[0012] The object processing method according to the present disclosure may be "[6] The object processing method according to [5] above, which includes a peripheral portion processing step of irradiating the laser light along a radial line extending radially from the inside to the outside in the peripheral portion to form the modified region." Thereby, when peeling off the peripheral portion, it becomes possible to surely realize the peeling.

[0013] The object processing method according to the present disclosure may be the one described in "[7] The object has a first substrate and a second substrate, a first device layer is formed on the main surface of the first substrate, a second device layer is formed on the main surface of the second substrate, and the first substrate and the second substrate are joined via the first device layer and the second device layer, the object processing method according to any one of [1] to [6] above". In such an object, for example, after peeling off a part of the object with a modified region across the virtual plane as a boundary, compared with an object having only one substrate, an effect of suppressing damage to the outer peripheral portion is exhibited.

[0014] The object processing method according to the present disclosure may be the one described in "[8] The laser processing step includes a first laser processing step of irradiating the laser light under a first processing condition along at least a first portion of the virtual plane to form the modified region, and after the first laser processing step, a second laser processing step of irradiating the laser light under a second processing condition along the virtual plane to form the modified region, the first processing condition is a condition in which a plurality of cracks included in the modified region are intermittently connected, and the second processing condition is a condition in which a plurality of cracks included in the modified region formed by the first and second laser processing steps are connected to each other after the second laser processing step and extend over the entire area of the virtual plane, the object processing method according to any one of [1] to [7] above". In such an object processing method, first, a plurality of intermittently connected cracks are formed along at least a first portion of the virtual plane by the first laser processing step, and then, by the subsequent second laser processing step, the plurality of cracks are connected and extended over the entire area of the virtual plane. In this case, the extension of the cracks over the entire area of the virtual plane can be suitably induced by the plurality of intermittently connected cracks. Therefore, it is possible to suppress the unintentional formation of cracks not along the virtual plane in the object as compared with the case where a plurality of cracks extending over the entire area of the virtual plane are formed all at once by a single laser processing.

Effects of the Invention

[0015] According to the present invention, it is possible to provide an object processing method capable of suppressing deterioration in the quality of the object after processing.

Brief Description of the Drawings

[0016]

Figure 1

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Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted.

[0018] As shown in FIG. 1, an object processing system 101 according to an embodiment is a system for processing an object 11, and includes a laser processing apparatus 1, an object transfer mechanism 40, and a grinding apparatus 60.

[0019] [Laser Processing Apparatus] The laser processing apparatus 1 is an apparatus that forms a modified region along a virtual plane inside the object 11 by irradiating the object 11 with laser light while aligning the condensing position (at least a part of the condensing region, the condensing point). Before grinding by the grinding apparatus 60, the laser processing apparatus 1 irradiates the object 11 with laser light along the processing line to form one or a plurality of rows of modified regions on the virtual plane inside the object 11. The laser processing apparatus 1 can perform trimming on the object 11. Trimming is a process for removing unnecessary parts from the object 11. In the present embodiment, the X direction and the Y direction are horizontal directions, and the Z direction is a vertical direction.

[0020] The laser processing apparatus 1 includes a stage 2, a laser processing head 3, a Z-axis rail 22, a Y-axis rail 24, an imaging unit 25, a GUI 9, and a control unit 8. The stage 2 is a support unit that supports the object 11. The stage 2 is configured to be rotatable about an axis parallel to the Z direction as a center line. The object 11 is placed on the stage 2. The stage 2 is rotationally driven by the driving force of a known driving device such as a motor.

[0021] As shown in FIGS. 1 and 2, the laser processing head 3 irradiates the object 11 placed on the stage 2 with the laser light L along the Z direction through the condensing unit 33, and forms a modified region 12 inside the object 11. The laser processing head 3 can linearly move in the Z direction along the Z-axis rail 22 by the driving force of a known driving device such as a motor. The laser processing head 3 can linearly move in the Y direction along the Y-axis rail 24 by the driving force of a known driving device such as a motor. The laser processing head 3 constitutes an irradiation unit.

[0022] The laser processing head 3 condenses the laser light L having transparency with respect to the object 11 and irradiates the object 11. When the laser light L is condensed inside the object 11, the laser light L is particularly absorbed in the portion corresponding to the condensing region C of the laser light L, and the modified region 12 is formed inside the object 11. The condensing region C is a region within a predetermined range from the position where the beam intensity of the laser light L is the highest or the centroid position of the beam intensity.

[0023] The modified region 12 is a region where the density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding non-modified region. Examples of the modified region 12 include a melting treatment region, a crack region, a dielectric breakdown region, a refractive index change region, etc. The modified region 12 includes a plurality of modified spots 12s and a plurality of cracks extending from each of the plurality of modified spots 12s. One modified spot 12s is formed by irradiating the laser beam L of one pulse.

[0024] The laser processing head 3 includes a light source 31, a spatial light modulator 7, and a condenser unit 33. The light source 31 outputs the laser beam L, for example, by a pulse oscillation method. Note that the laser processing head 3 may be configured not to have the light source 31 and to introduce the laser beam L from the outside of the laser processing head 3. The spatial light modulator 7 modulates the laser beam L output from the light source 31. The condenser unit 33 condenses the laser beam L (that is, the laser beam that has passed through the spatial light modulator 7) that has been modulated by the spatial light modulator 7 and output from the spatial light modulator 7 toward the object 11. The condenser unit 33 includes a condenser lens.

[0025] In the spatial light modulator 7, when a signal indicating a modulation pattern is input from the control unit 8, the modulation pattern is displayed according to the signal. The modulation pattern is for modulating the laser beam L. In the spatial light modulator 7, when the laser beam L is incident from the outside, reflected, and emitted to the outside in a state where the modulation pattern is displayed, the laser beam L is modulated according to the displayed modulation pattern. Thus, according to the spatial light modulator 7, by appropriately setting the modulation pattern to be displayed, modulation of the laser beam L (for example, modulation of the intensity, amplitude, phase, polarization, etc. of the laser beam L) is possible. In the laser processing head 3, the laser beam L output from the light source 31 is incident on the condenser unit 33 via the spatial light modulator 7 and is condensed into the object 11 by the condenser unit 33, so that the modified region 12 is formed in the object 11 in the portion corresponding to the condensing region C.

[0026] Returning to FIG. 1, the Z-axis rail 22 is a rail extending along the Z direction. The Z-axis rail 22 is attached to the laser processing head 3 via the attachment portion 21. The Z-axis rail 22 moves the laser processing head 3 along the Z direction so that the condensing position of the laser beam L moves along the Z direction. The Y-axis rail 24 is a rail extending along the Y direction. The Y-axis rail 24 is attached to the Z-axis rail 22 via the attachment portion 23. The Y-axis rail 24 moves the laser processing head 3 along the Y direction so that the condensing position of the laser beam L moves along the Y direction.

[0027] The imaging unit 25 images the object 11 from a direction along the incident direction of the laser beam L. The imaging unit 25 includes an alignment camera AC and an imaging unit IR. The alignment camera AC and the imaging unit IR are attached to the attachment portion 21 together with the laser processing head 3. The alignment camera AC images, for example, a device pattern or the like using light transmitted through the object 11. The image obtained thereby is used for alignment of the irradiation position of the laser beam L with respect to the object 11.

[0028] The control unit 8 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 8, software (program) read into the memory or the like is executed by the processor, and reading and writing of data in the memory and the storage, as well as communication by the communication device, are controlled by the processor. The control unit 8 controls each part of the laser processing apparatus 1 and realizes various functions.

[0029] The control unit 8 controls at least the stage 2, the laser processing head 3, the movement of the laser processing head 3 along the Z-axis rail 22, and the movement of the laser processing head 3 along the Y-axis rail 24. The control unit 8 controls the rotation of the stage 2, the irradiation of the laser beam L from the laser processing head 3, and the movement of the condensing position of the laser beam L. The control unit 8 can execute various controls based on rotation information regarding the rotation amount of the stage 2 (hereinafter, also referred to as "θ information"). The θ information may be obtained from the driving amount of the driving device that rotates the stage 2, or may be obtained by a separate sensor or the like. The θ information can be obtained by various known methods.

[0030] While rotating the stage 2, the control unit 8 controls the start and stop of the irradiation of the laser beam L in the laser processing head 3 based on the θ information under AF tracking control in a state where the condensing position is positioned on the virtual plane M in the object 11, thereby performing a trimming process for forming the modified region 12 along the virtual plane M. The trimming process is a process of the control unit 8 that realizes trimming.

[0031] The GUI 9 displays various information. The GUI 9 includes, for example, a touch panel display. Various settings regarding the processing conditions are input to the GUI 9 by operations such as user touch. The GUI 9 constitutes an input unit that receives input from the user. The example shown in FIG. 3(a) is a diagram showing an example of the input / output screen of the GUI 9. FIG. 3(a) shows an example in the case of forming four columns of modified regions 12 inside the object 11. In FIG. 3(a), SD1, SD2, SD3, and SD4 indicate the modified regions 12 that are far from the laser beam incident surface in this order. The Z height corresponds to the planned formation position of the modified region 12. The Z height is defined with the laser beam incident surface as the reference (0), and the value increases as it goes from the laser beam incident surface into the object 11. The planned formation position of the modified region 12 is represented, for example, by Z height × DZ rate ± α. The DZ rate is a preset value. α is a correction value according to various processing condition settings and is a value determined by experience. The output corresponds to the output of the laser beam L when forming the modified region 12.

[0032] In the GUI9, the user can input the Z height, output, and detailed conditions of each of SD1 to SD4. Each condition set in the laser processing apparatus 1 can be set based on the thickness of the semiconductor device 11K (see FIG. 7(b)) finally obtained after the grinding process described later (hereinafter also referred to as "finished thickness"). For example, in a setting example of processing conditions with a finished thickness of 50 μm, in the GUI9, the user sets the Z height of SD1 so that the distance from the modified region 12 corresponding to SD1 to the back surface 11b exceeds the finished thickness. Here, considering the length of crack propagation, 175 μm is input for the Z height of SD1.

[0033] Also, in the GUI9, the user can input an error detection position, which is an AF meandering detection position for suppressing meandering when further meandering occurs. The control unit 8 calculates, as a monitoring process, the meandering amount of the AF tracking control (the displacement amount in the optical axis direction when the position of the modified region 12 deviates from the planned formation position of the modified region 12), and monitors whether the calculated meandering amount exceeds the distance in the Z direction from the planned formation position of the modified region 12 to the error detection position (hereinafter also referred to as "meandering allowable range"). When the control unit 8 determines in the monitoring process that the meandering amount exceeds the meandering allowable amount, the control unit 8 displays an error on the GUI9. When the control unit 8 determines in the monitoring process that the meandering amount exceeds the meandering allowable amount, the control unit 8 can execute control to turn off the laser light, control to fix the condensing unit 33 (fix the actuator), control to forcibly raise the condensing unit 33, or change the control parameters (change to suppress overshoot by suppressing the control).

[0034] Note that in the GUI9, although the error detection position can be input, the meandering allowable range may also be input, the voltage value of the actuator that drives the condensing unit 33 in the Z direction may also be input, the differential signal or displacement sensor signal value in the AF tracking control may also be input, or the allowable displacement amount of the semiconductor device 11K (see FIG. 7(b)) finally obtained after the grinding process described later may also be input.

[0035] [Object Transfer Mechanism] The object transfer mechanism 40 is a mechanism for transferring the object 11 after processing by the laser processing apparatus 1 to the grinding apparatus 60. The object transfer mechanism 40 includes an arm 41 capable of holding the object 11, a slider 42 provided on the proximal end side of the arm 41, and a rail 43 for moving the slider 42 in the horizontal direction. The configuration of the object transfer mechanism 40 is not particularly limited, and various known configurations can be adopted as long as the object 11 can be transferred between the laser processing apparatus 1 and the grinding apparatus 60.

[0036] The object transfer mechanism 40 includes a control unit 48 and a GUI 49. The control unit 48 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 48, software read into the memory and the like is executed by the processor, and the reading and writing of data in the memory and the storage, as well as communication by the communication device, are controlled by the processor. The control unit 48 controls each part of the object transfer mechanism 40 to realize various functions. The GUI 49 displays various information. The GUI 49 includes, for example, a touch panel display. Various settings related to the transfer conditions are input to the GUI 49 by operations such as user touches.

[0037] [Grinding Apparatus] The grinding apparatus 60 is a device for grinding the object 11 after processing by the laser processing apparatus 1. The grinding apparatus 60 is a device for grinding the removal region 11Z (see FIG. 6(a)) from the surface 11a of the object 11 to the planned grinding position (planned grinding depth). The grinding apparatus 60 includes a polishing wheel 61 which is a grinding wheel capable of rotating at high speed, a base 62 for rotatably supporting the polishing wheel, a vertical rail 63 for moving the base 62 in the vertical direction, a horizontal rail 64 for moving the base 62 in the horizontal direction, a thickness gauge 66 for measuring the thickness of the object 11 to be ground, and a stage 67 on which the object 11 to be ground is placed. The stage 67 is configured to be rotatable about an axis parallel to the vertical direction as a center line.

[0038] The grinding device 60 includes a control unit 68 and a GUI 69. The control unit 68 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control unit 68, software read into the memory and the like is executed by the processor, and the reading and writing of data in the memory and the storage, as well as the communication by the communication device, are controlled by the processor. The control unit 68 controls each part of the grinding device 60 to realize various functions. The GUI 69 displays various information. The GUI 69 includes, for example, a touch panel display. Various settings regarding the grinding conditions are input into the GUI 69 by operations such as the user's touch.

[0039] The example shown in FIG. 3(b) is a diagram showing an example of the input / output screen of the GUI 69. In the figure, the stage rotation speed is the rotation speed of the stage 67 during grinding by the grinding device 60. The polishing wheel rotation speed is the rotation speed of the polishing wheel 61 during grinding by the grinding device 60. In the GUI 69, the user can input the pre-processing thickness, the finish thickness, the stage rotation speed, the polishing wheel rotation speed, and the detailed conditions. Each condition set in the grinding device 60 can be set based on the finish thickness. For example, in the GUI 69, the user assumes the thickness of a 12-inch wafer and inputs 775 μm for the thickness of the object 11 before processing and 50 μm for the finish thickness. When the object 11 is bonded to a 100-μm tape material, the user may input 875 μm for the thickness of the object 11 before processing and 50 μm for the finish thickness in the GUI 69.

[0040] Next, the main part of this embodiment will be further described.

[0041] As shown in FIGS. 4(a) and 4(b), the object 11 is, for example, a silicon wafer. The object 11 includes a front surface 11a which is a first major surface, and a back surface 11b which is a second major surface opposite to the front surface 11a. A device layer including a plurality of functional elements is formed on the back surface 11b of the object 11. The object 11 is supported by the stage 2 such that the front surface 11a faces the laser processing head 3 side (that is, the front surface 11a is used as the laser light incident surface and the back surface 11b faces the stage 2 side).

[0042] The object 11 includes a main body portion R which is an effective region and a peripheral portion E which is a removal region. The main body portion R is a circular portion including the central portion of the object 11 when viewed from the Z direction which is the direction facing the front surface 11a (the thickness direction of the object 11). The peripheral portion E is a region located outside the main body portion R in the object 11. The peripheral portion E is a portion located at the periphery of the object 11 when viewed from the Z direction, and here, it is the outer edge portion other than the main body portion R in the object 11. The peripheral portion E is an annular portion surrounding the main body portion R. The peripheral portion E includes a bevel portion at the outer edge of the object 11.

[0043] A virtual surface M is set as a surface to be peeled on the object 11. The virtual surface M is a surface where the formation of the modified region 12 is planned. The virtual surface M is a virtual region. The virtual surface M is not limited to a plane and may be a curved surface or a three-dimensional surface. The setting of the virtual surface M can be performed in the control unit 8. The virtual surface M may be specified by coordinates.

[0044] As shown in FIG. 5, a processing line 5 having a plurality of parallel lines 5a arranged so as to line up on a virtual plane M is set on the object 11. The processing line 5 is a virtual line. The plurality of parallel lines 5a are set parallel to the XY plane. The plurality of parallel lines 5a extend in an annular shape with different diameters from each other. The extending direction of the parallel line 5a corresponds to the processing progress direction in which the laser beam L travels (scanning direction). The direction in which the parallel lines 5a line up corresponds to the index direction. The index direction is a direction orthogonal to the extending direction of the parallel line 5a as viewed from the laser beam incident surface. The index direction is, for example, the direction in which the laser processing head 3 is translated parallel to the stage 2 when moving the condensing position of the laser beam L. The setting of the processing line 5 can be performed in the control unit 8. The processing line 5 may be specified by coordinates.

[0045] As shown in FIG. 6(a), in the present embodiment, a part on the surface 11a side of the object 11 is a removal region 11Z. The removal region 11Z here is a disk-shaped region. The removal region 11Z can be obtained based on, for example, the pre-processing thickness and the finish thickness input by the user in the GUI 69.

[0046] The virtual plane M includes a first plane M11 extending in a direction intersecting the surface 11a, a second plane M12 connected to the back surface 11b side (opposite side to the surface 11a side) of the first plane M11 via a connection portion J and extending in a direction intersecting the first plane M11, a third plane M13 connected to the back surface 11b side of the second plane M12 and extending in a direction intersecting the second plane M12, and a fourth plane M14 connected to the back surface 11b side of the third plane M13 and extending in a direction intersecting the third plane M13.

[0047] The first surface M11 is a surface formed inside the object 11 along the boundary between the peripheral portion E and the main body portion R. The first surface M11 is a surface having a shape corresponding to the circumferential surface of a cylinder. The surface 11a side of the first surface M11 reaches the surface 11a. The second surface M12 is a surface having a shape corresponding to the circumferential surface of a frustum of a cone. The second surface M12 is an inclined surface that inclines radially inward with respect to the Z direction as it approaches the surface 11a. The third surface M13 is a surface having a shape corresponding to the circumferential surface of a frustum of a cone. The third surface M13 is an inclined surface that inclines radially inward with respect to the Z direction as it approaches the surface 11a. The fourth surface M14 is an annular surface and is a plane parallel to the XY plane. The radially outer side of the fourth surface M14 reaches the side surface of the object 11.

[0048] As shown in FIG. 6(b), when a cross-section including the central axis of the object 11 and along the Z direction is viewed (hereinafter referred to as "cross-sectional view along the Z direction"), the first angle θ1 formed by the first surface M11 and the second surface M12, the second angle θ2 formed by the surface 11a and the second surface M12, and the third angle θ3 formed by the second surface M12 and the third surface M13 are obtuse angles. In other words, the obtuse angle formed by the first surface M11 and the second surface M12 is the first angle θ1, the obtuse angle formed by the surface 11a and the second surface M12 is the second angle θ2, and the obtuse angle formed by the second surface M12 and the third surface M13 is the third angle θ3. The first angle θ1 is smaller than the second angle θ2. The first angle θ1 is smaller than the third angle θ3. The connection portion J between the first surface M11 and the second surface M12 is provided in the removal region 11Z in the object 11. Note that the cross-sectional view along the Z direction corresponds to a cross-sectional view that intersects the surface 11a.

[0049] In the object processing method of this embodiment, as shown in Fig. 6(c), the object 11 is irradiated with a laser beam L by the laser processing apparatus 1, and a modified region 12 is formed along a virtual plane M inside the object 11 (laser processing step). Specifically, in the laser processing step, the laser beam L is irradiated onto the object 11 by the laser processing head 3, the laser beam L is focused on a processing line 5 set on the virtual plane M inside the object 11, and while rotating the stage 2 so that the focusing position of the laser beam L moves along the processing line 5, AF tracking control is performed to make the focusing position follow the displacement of the surface 11a which is the laser beam incident surface. This laser processing is repeatedly performed for all the processing lines 5 on the virtual plane M. Thereby, the modified region 12 is formed in the object 11 along the virtual plane M. Note that the order of laser processing for each surface of the virtual plane M is not particularly limited. The order of laser processing for the first surface M11, the second surface M12, the third surface M13, and the fourth surface M14 of the virtual plane M is arbitrary.

[0050] Subsequently, as shown in Fig. 7(a), after the laser processing step, an external stress is applied to the object 11, and a part of the peripheral edge E is peeled off with the modified region 12 extending across the virtual plane M as a boundary (peeling step). Subsequently, based on the conveyance conditions and the like input via the GUI 49, the object 11 is conveyed from the laser processing apparatus 1 to the grinding apparatus 60 by the object conveyance mechanism 40. Based on the grinding conditions and the like input via the GUI 69, the grinding step (removing step) is performed by the grinding apparatus 60. That is, as shown in Fig. 7(b), for the removal region 11Z of the object 11 after the peeling step, grinding is performed by the grinding wheel 61 to remove it. As a result of the above, the semiconductor device 11K is obtained (manufactured). Note that between the peeling step and the removing step, unevenness flattening processing by laser processing or etching processing may be performed.

[0051] Here, in the object processing method of the present embodiment, by defining the first angle θ1 and the second angle θ2 as described above, for example, when the peripheral edge E of the object 11 is peeled off with the modified region 12 extending across the virtual plane M as a boundary, a remaining portion 11P (hereinafter also simply referred to as "remaining portion 11P"), which is a part of the object that could not be completely peeled off, can be made to tend to remain concentrated around the location corresponding to the connection portion J (see Fig. 6(a)) on the peeling surface. The peeling surface is the surface corresponding to the virtual plane M of the object 11 after peeling off the peripheral edge E. The peeling surface is the surface corresponding to the boundary between the object 11 and the peripheral edge E.

[0052] Also, by defining the first angle θ1 and the second angle θ2 as described above, for example, during the formation of the modified region 12 by a laser processing step, the remaining portion 11P can be made to tend to remain concentrated around the location corresponding to the connection portion J. In the illustrated example, the remaining portion 11P remains randomly and locally in an annular groove portion formed by the peeling surface H11 corresponding to the first plane M11 and the peeling surface H12 corresponding to the second plane M12. The reason for this is that when the removal region 11Z is removed, due to the way the external stress is applied, the remaining portion 11P is more likely to remain around the location corresponding to the connection portion J.

[0053] And since the connection portion J is provided in the removal region 11Z, the remaining portion 11P will also be removed when the removal region 11Z is removed. That is, by shifting the position where the remaining portion 11P can be concentratedly generated in the Z direction to a position shallower than the planned grinding position, it is possible to suppress the remaining portion 11P from remaining on the object 11 after the grinding process. Therefore, it is possible to suppress the remaining portion from having an adverse effect on the quality of the semiconductor device 11K, which is the object 11 after processing. Thus, it is possible to suppress the deterioration of the quality of the object 11 after processing.

[0054] In the object processing method, the object 11 is configured to include a peripheral edge E and a main body portion R, and the first plane M11 is formed inside the object 11 along the boundary between the peripheral edge E and the main body portion R in the object 11. In this case, at least a part of the peripheral edge E can be peeled off with the modified region 12 extending across the virtual plane M as a boundary.

[0055] The object processing method includes a peeling step of peeling the peripheral portion E with the modified region 12 as a boundary after the laser processing step, and a removing step of removing the removal region 11Z of the object 11 after the laser processing step. In this case, a part of the object 11 can be peeled off and the removal region 11Z can be removed. In the object processing method, the removing step is a grinding step of removing the removal region 11Z by grinding. In this case, the removing step can be specifically realized.

[0056] In the object processing method, the virtual plane M includes the third plane M13. In a cross-sectional view along the Z direction, the third angle θ3 formed by the second plane M12 and the third plane M13 is an obtuse angle, and the first angle θ1 is smaller than the third angle θ3. Even in this case, for example, when a part of the object 11 is peeled off with the modified region 12 as a boundary and / or during the formation of the modified region 12 by the laser processing step, it is possible to easily concentrate the remaining portion 11P around the location corresponding to the connection portion J on the peeling surface. Also, it becomes easy to adjust the position of the first plane M11 on the object 11 according to the user's requirements without changing the first angle θ1.

[0057] In the present embodiment, the fourth plane M14 formed near the back surface 11b of the object 11 may be set to be more preferable as it approaches the object 11, and at least a part thereof may overlap the back surface 11b. In this case, it becomes possible to make the object 11 thinner by the subsequent grinding step. On the contrary, the fourth plane M14 may be set to be separated from the back surface 11b of the object 11 by a certain distance or more. In this case, it is possible to suppress the formation of cracks (so-called bottom cracks) that do not follow the virtual plane toward the back surface 11b of the object 11.

[0058] [Modification Example] As described above, one aspect of the present disclosure is not limited to the above embodiment.

[0059] In the above embodiment, the virtual plane M is not particularly limited, and various aspects can be adopted as exemplified below.

[0060] Figure 8(a) is a side sectional view of the object 11 showing the virtual surface M according to the first modification. As shown in Figure 8(a), the virtual surface M according to the first modification is different from the virtual surface M (see Figure 6(a)) according to the above embodiment in that it includes a first surface M21 instead of the first surface M11. The first surface M21 is a surface having a shape corresponding to the peripheral surface of a frustum of a cone. The first surface M21 is an inclined surface that inclines radially inward with respect to the Z direction as it approaches the surface 11a. The side of the first surface M21 on the surface 11a side reaches the surface 11a. A second surface M12 is connected to the back surface 11b side of the first surface M21 via a connection portion J2. As shown in Figure 8(b), in a cross-sectional view along the Z direction, the first angle θ21 formed by the first surface M21 and the second surface M12 is an obtuse angle. In other words, the obtuse angle formed by the first surface M21 and the second surface M12 is the first angle θ21. The first angle θ21 is smaller than the second angle θ2. The first angle θ21 is smaller than the third angle θ3. The connection portion J between the first surface M21 and the second surface M12 is provided in the removal region 11Z in the object 11.

[0061] When processing the object 11 in which the virtual surface M according to the first modification is set, the object 11 is irradiated with laser light L by the laser processing apparatus 1, and a modified region 12 is formed along the virtual surface M inside the object 11. Subsequently, as shown in Figure 8(c), an external stress is applied to the object 11, and a part of the peripheral edge E is peeled off with the modified region 12 extending over the virtual surface M as a boundary. In this case, it is possible to make the remaining portion 11P concentrate and remain easily around the location corresponding to the connection portion J2 of the virtual surface M on the peeling surface. Even in such a processing method, the above-described effects can be achieved.

[0062] Figure 9(a) is a side sectional view of the object 11 showing the virtual surface M according to the second modification. As shown in Figure 9(a), the virtual surface M according to the second modification is different from the virtual surface M (see Figure 8(a)) according to the first modification in that it includes a second surface M32 instead of the second surface M12, the third surface M13, and the fourth surface M14.

[0063] The second surface M32 is an inclined surface that inclines toward the surface 11a side with respect to the horizontal direction as it goes radially inward. The second surface M32 is connected to the back surface 11b side of the first surface M21 via the connection portion J3 and extends in a direction intersecting the first surface M21. The radially outer side of the second surface M32 is located near the back surface 11b of the object 11 and reaches the side surface of the object 11. As shown in FIG. 9(b), in a cross-sectional view along the Z direction, the first angle θ31 formed by the first surface M21 and the second surface M32, and the second angle θ32 formed by the second surface M32 and the surface 11a are obtuse angles. In other words, the obtuse angle formed by the first surface M21 and the second surface M32 is the first angle θ31, and the obtuse angle formed by the second surface M32 and the surface 11a is the second angle θ32. The first angle θ31 is smaller than the second angle θ32. The connection portion J3 between the first surface M21 and the second surface M32 is provided in the removal region 11Z of the object 11.

[0064] When processing the object 11 in which the virtual surface M according to the second modification is set, the object 11 is irradiated with the laser beam L by the laser processing apparatus 1, and the modified region 12 is formed along the virtual surface M inside the object 11. Subsequently, as shown in FIG. 9(c), an external stress is applied to the object 11, and a part of the peripheral edge E is peeled off with the modified region 12 extending across the virtual surface M as a boundary. In this case, it is possible to make the remaining portion 11P likely to remain concentratedly around the location corresponding to the connection portion J3 of the virtual surface M on the peeling surface. Even in such a processing method, the above-described operational effects are achieved.

[0065] FIG. 10(a) is a side cross-sectional view of the object 11 showing the virtual surface M according to the third modification. As shown in FIG. 10(a), the virtual surface M according to the third modification is different from the virtual surface M (see FIG. 8(a)) according to the first modification in that the second surface M42 is included instead of the second surface M12 and the third surface M13.

[0066] The second surface M42 is an inclined curved surface that approaches the surface 11a with respect to the horizontal plane as it goes radially inward and bends so as to be convex toward the back surface 11b in a cross-sectional view along the Z direction. The radially inner side of the second surface M42 is connected to the back surface 11b side of the first surface M21 via a connection portion J4. The radially outer side of the second surface M42 is connected to the radially inner side of the fourth surface M14. As shown in FIG. 10(b), in a cross-sectional view along the Z direction, the first angle θ41 formed by the first surface M21 and the second surface M42, and the second angle θ42 formed by the second surface M42 and the surface 11a are obtuse angles. In other words, the obtuse angle formed by the first surface M21 and the second surface M42 is the first angle θ41, and the obtuse angle formed by the second surface M42 and the surface 11a is the second angle θ42. The first angle θ41 is smaller than the second angle θ42. The connection portion J4 between the first surface M21 and the second surface M42 is provided in the removal region 11Z of the object 11.

[0067] Since the second surface M42 is a curved surface, in a cross-sectional view along the Z direction, the angle formed by the first surface M21 and the second surface M42 can be approximated as, for example, the angle with the tangential direction of the second surface M42 passing through the midpoint of the first surface M21 and the second surface M42. Similarly, since the second surface M42 is a curved surface, in a cross-sectional view along the Z direction, the angle formed by the second surface M42 and the surface 11a can be approximated as the angle between the tangential direction of the second surface M42 passing through the midpoint of the second surface M42 and the surface 11a. The same applies to the following curved surfaces.

[0068] When machining the object 11 in which the virtual surface M according to the third modification example is set, the object 11 is irradiated with the laser light L by the laser processing apparatus 1, and the modified region 12 is formed along the virtual surface M inside the object 11. Subsequently, as shown in FIG. 10(c), an external stress is applied to the object 11, and a part of the peripheral edge E is peeled off with the modified region 12 extending over the virtual surface M as a boundary. In this case, it is possible to concentrate the remaining portion 11P likely to remain around the location corresponding to the connection portion J4 of the virtual surface M on the peeling surface. Even in such a processing method, the above-described effects can be obtained.

[0069] FIG. 11(a) is a side sectional view of the object 11 showing the virtual surface M according to the fourth modification. As shown in FIG. 11(a), the virtual surface M according to the fourth modification is different from the virtual surface M (see FIG. 8(a)) according to the first modification in that it includes a first surface M51 and a second surface M52 instead of the first surface M21, the second surface M12, the third surface M13, and the fourth surface M14.

[0070] The first surface M51 is different in that it is set to be located radially outside the first surface M21, and is otherwise configured in the same manner as the first surface M21. The second surface M52 is an inclined curved surface that approaches the surface 11a with respect to the horizontal plane as it goes radially inward and bends so as to be convex toward the back surface 11b in a cross-sectional view along the Z direction. The radially inner side of the second surface M52 is connected to the back surface 11b side of the first surface M51 via a connection portion J5. The radially outer side of the second surface M52 is located near the back surface 11b of the object 11 and reaches the side surface of the object 11. As shown in FIG. 10(b), in a cross-sectional view along the Z direction, the first angle θ51 formed by the first surface M51 and the second surface M52, and the second angle θ52 formed by the second surface M52 and the surface 11a are obtuse angles. The first angle θ51 is smaller than the second angle θ52. The connection portion J5 between the first surface M51 and the second surface M52 is provided in the removal region 11Z of the object 11.

[0071] When processing the object 11 provided with the virtual surface M according to the fourth modification, the object 11 is irradiated with the laser beam L by the laser processing apparatus 1 to form a modified region 12 along the virtual surface M inside the object 11. Subsequently, as shown in FIG. 11(c), an external stress is applied to the object 11, and a part of the peripheral edge E is peeled off with the modified region 12 extending across the virtual surface M as a boundary. In this case, it is possible to concentrate the remaining portion 11P easily around the location corresponding to the connection portion J5 of the virtual surface M on the peeling surface. Even in such a processing method, the above-described operational effects are achieved.

[0072] FIG. 12(a) is a side sectional view of the object 11 showing the virtual surface M according to the fifth modification. As shown in FIG. 12(a), the virtual surface M according to the fifth modification is different from the virtual surface M (see FIG. 10(a)) according to the third modification in that it includes a second surface M62 and a fourth surface M64 instead of the second surface M42 and the fourth surface M14.

[0073] The second surface M62 is an inclined curved surface that approaches the surface 11a with respect to the horizontal plane as it goes radially inward and bends so as to be convex toward the back surface 11b in a cross-sectional view along the Z direction. The radially inner side of the second surface M62 is connected to the back surface 11b side of the first surface M21 via a connection portion J6. The radially outer side of the second surface M62 overlaps (contacts) the back surface 11b of the object 11. The fourth surface M64 is an annular surface and is a plane parallel to the XY plane. The radially inner side of the fourth surface M64 is connected to the radially outer side of the second surface M62.

[0074] In a cross-sectional view along the Z direction, the first angle formed by the first surface M21 and the second surface M62, and the second angle formed by the second surface M62 and the surface 11a are obtuse angles. In other words, the obtuse angle formed by the first surface M21 and the second surface M62 is the first angle, and the obtuse angle formed by the second surface M62 and the surface 11a is the second angle. The first angle is smaller than the second angle. The connection portion J6 between the first surface M21 and the second surface M62 is provided in the removal region 11Z of the object 11. When the above-described laser processing step and peeling step are performed on the object 11 in which the virtual surface M according to the fifth modification is set, it is possible to concentrate the remaining portion 11P around the location corresponding to the connection portion J6 of the virtual surface M on the peeling surface. Even in such a processing method, the above-described effects can be achieved.

[0075] FIG. 12(b) is a side sectional view of the object 11 showing the virtual surface M according to the sixth modification. As shown in FIG. 12(b), the virtual surface M according to the sixth modification is different from the virtual surface M (see FIG. 11(a)) according to the fourth modification in that it includes a second surface M72 instead of the second surface M52.

[0076] The second surface M72 is an inclined curved surface that approaches the surface 11a with respect to the horizontal plane as it goes radially inward and bends so as to be convex toward the back surface 11b in a cross-sectional view along the Z direction. The radially inner side of the second surface M72 is connected to the back surface 11b side of the first surface M51 via a connecting portion J7. The radially outer side of the second surface M72 overlaps (contacts) the back surface 11b of the object 11.

[0077] In a cross-sectional view along the Z direction, the first angle formed by the first surface M51 and the second surface M72, and the second angle formed by the second surface M72 and the surface 11a are obtuse angles. In other words, the obtuse angle formed by the first surface M51 and the second surface M72 is the first angle, and the obtuse angle formed by the second surface M72 and the surface 11a is the second angle. The first angle is smaller than the second angle. The connecting portion J7 between the first surface M51 and the second surface M72 is provided in the removal region 11Z of the object 11. When the above-described laser processing step and peeling step are performed on the object 11 in which the virtual surface M according to the sixth modification example is set, it is possible to concentrate and easily leave the remaining portion 11P around the location corresponding to the connecting portion J7 of the virtual surface M on the peeling surface. Even in such a processing method, the above-described effects can be obtained.

[0078] In the above embodiment, the laser processing step may include a first laser processing step of irradiating the laser beam L under a first processing condition along at least a first portion of the virtual surface M to form the modified region 12, and a second laser processing step of irradiating the laser beam L under a second processing condition along the virtual surface M after the first laser processing step to form the modified region 12. The first processing condition is a condition under which a plurality of cracks included in the modified region 12 are intermittently connected, and the second processing condition may be a condition under which a plurality of cracks included in the modified region 12 formed by the first and second laser processing steps are connected to each other after the second laser processing step and extend over the entire area of the virtual surface M. Hereinafter, an example will be described.

[0079] First, with respect to the object 11 on which the virtual plane M shown in FIG. 6(a) is set, the laser beam L is irradiated under the first processing condition along the second plane M12 and the third plane M13, which are the first parts of the virtual plane M. As a result, as shown in FIG. 13(a), a modified region 12a is formed along the second plane M12 and the third plane M13 inside the object 11 (the first laser processing step). Specifically, in the first laser processing step, the laser beam L is irradiated onto the object 11 by the laser processing head 3 under the first processing condition, and the laser beam L is focused on the processing line 5 set on the second plane M12 and the third plane M13 of the virtual plane M inside the object 11. While rotating the stage 2 so that the focusing position of the laser beam L moves along the processing line 5, AF tracking control is performed to make the focusing position follow the displacement of the surface 11a, which is the laser beam incident surface. This laser processing is repeatedly performed for all the processing lines 5 on the second plane M12 and the third plane M13. Thereby, the modified region 12a is formed along the second plane M12 and the third plane M13.

[0080] The first processing condition is a condition under which a plurality of cracks included in the modified region 12a are intermittently connected. The first processing condition is a condition under which the processing state of the modified region 12a of the second plane M12 and the third plane M13 after the first laser processing step becomes the first slicing state. The first slicing state is a slicing stealth state in which at least a part of the plurality of cracks included in the modified region 12a are not connected to each other in both the processing progress direction and the index direction (the direction intersecting the processing progress direction). The first slicing state may be a slicing half-cut state in which at least a part of the plurality of cracks included in the modified region 12a are not connected to each other in the index direction. That is, in the first laser processing step, a modified region 12a (here, the modified region 12a in the first slicing state) in which a plurality of included cracks are intermittently connected is formed along the second plane M12 and the third plane M13 of the virtual plane M. The laser processing in the first laser processing step is also referred to as dot line processing.

[0081] Subsequently, in the laser processing step, as shown in FIG. 13(b), after the first laser processing step, along the first surface M11 and the fourth surface M14 of the virtual surface M, laser light L is irradiated under the second processing conditions to form a modified region 12b (second laser processing step). Specifically, in the second laser processing step, the laser head 3 irradiates the object 11 with the laser light L under the second processing conditions, and the laser light L is focused on the processing lines 5 set on the first surface M11 and the fourth surface M14, which are the portions other than the first portion on the virtual surface M inside the object 11. At the same time, while rotating the stage 2 so that the focusing position of the laser light L moves along the processing line 5, AF tracking control is performed to make the focusing position follow the displacement of the surface 11a, which is the laser light incident surface. This laser processing is repeatedly performed for all the processing lines 5 on the first surface M11 and the fourth surface M14. Thereby, the modified region 12b is formed along the first surface M11 and the fourth surface M14.

[0082] The second processing conditions are conditions under which a plurality of cracks included in the modified regions 12a and 12b formed by the first laser processing step and the second laser processing step are connected to each other after the second laser processing step and extend over the entire area of the virtual surface M. The second processing conditions are conditions under which the processing state of the modified region 12 over the entire area of the virtual surface M after the second laser processing step becomes the second slicing state. The second slicing state is a slicing full cut state in which a plurality of cracks included in the modified region 12 extend and are connected to each other in the processing progress direction and the direction intersecting the processing progress direction. That is, in the second laser processing step, the modified region 12b in the second slicing state is formed along the first surface M11 and the fourth surface M14, and the modified region 12a in the first slicing state that has already been formed in the first laser processing step changes to the modified region 12c in the second slicing state as the cracks extend along with the formation of the modified region 12b.

[0083] The slicing stealth (SST) state is a state in which cracks have not extended from a plurality of modified spots (indentations) 12s included in the modified region 12, or the cracks are not connected. The slicing stealth state is a state in which only the modified spots 12s can be observed by the imaging unit 25. In the slicing stealth state, since there is no crack extension, even if the number of processing lines is increased, the state will not change to the slicing full cut state.

[0084] The slicing half cut (SHC) state is a state in which cracks extending from a plurality of modified spots 12s included in the modified region 12 extend in a direction along the parallel line 5a (processing progress direction). The slicing full cut (SFC) state is a state in which cracks extending from a plurality of modified spots 12s included in the modified region 12 extend in directions along a plurality of parallel lines 5a and in a direction intersecting the parallel line 5a and are connected to each other. The slicing full cut state is a state in which cracks extending from the modified spots 12s are connected across a plurality of parallel lines 5a. Since the slicing full cut state is generated by the connection of cracks straddling between a plurality of parallel lines 5a, it cannot occur when the modified region 12 is formed by irradiating the laser beam L along a single parallel line 5a. In order to generate the slicing full cut state, the slicing half cut state is indispensable as the processing state when the modified region 12 is formed by irradiating the laser beam L along a single parallel line 5a.

[0085] In such an object processing method, by the first laser processing step, a plurality of intermittently connected cracks are formed along the first part of the virtual surface M, and then by the subsequent second laser processing step, the plurality of cracks are connected and extended over the entire area of the virtual surface M. In this case, the extension of cracks over the entire area of the virtual surface M can be preferably induced by the plurality of intermittently connected cracks. Therefore, compared with the case where cracks extending over the entire area of the virtual surface M are formed all at once by a single laser processing, it is possible to suppress the unintentional formation of cracks not along the virtual surface M (initial cracks extending in a direction other than the direction along the virtual surface M) in the object 11.

[0086] In the above embodiment, for example, the object 11 (see FIG. 4(b) etc.), which is a silicon wafer, is adopted. However, the object is not particularly limited, and as shown in FIG. 14, the object 111, which is a bonded wafer, may be adopted. The object 111 has a first substrate 151 and a second substrate 152. The first substrate 151 and the second substrate 152 correspond to the object 11.

[0087] On the back surface 151b, which is the main surface of the first substrate 151, a first device layer 161 including a plurality of functional elements is formed. On the front surface 152a, which is the main surface of the second substrate 152, a second device layer 162 including a plurality of functional elements is formed. The first substrate 151 and the second substrate 152 are joined via the first device layer 161 and the second device layer 162. In such an object 111 of the bonded wafer, for example, after peeling the peripheral edge E with the modified region 12 crossing the virtual plane M as a boundary, compared with the object 11 having one substrate, it has the effect of suppressing the breakage of the outer peripheral part.

[0088] For example, in the object 111, when peeling the peripheral edge E with the modified region 12 crossing the virtual plane M formed on the first substrate 151 as a boundary, the crack may extend radially inward from the bonding surface between the first device layer 161 and the second device layer 162, then cross the first device layer 161 pattern and reach the modified region 12 inside the first substrate 151, and extend along the modified region 12.

[0089] Note that the virtual plane M formed near the back surface 151b of the first substrate 151 in the object 111 is preferably closer to the object 11, and may be set so that at least a part thereof overlaps the back surface 151b. In this case, it is possible to suppress the crack extending from the bonding surface between the first device layer 161 and the second device layer 162 and reaching the modified region 12 of the first substrate 151 from progressing to the central part in the thickness direction of the first substrate 151.

[0090] FIG. 15 is a side view showing a semiconductor device 111K obtained by implementing the object processing method of the above-described embodiment on the first substrate 151 of the object 111 in FIG. 14. In the semiconductor device 111K, a surface 71 on a side opposite to the second substrate 152 side of the first substrate 151 has an inclined surface 72 at its end.

[0091] The inclined surface 72 is inclined so as to incline toward the back surface 151b side as it goes radially outward. The inclined surface 72 extends in an annular shape when viewed from the Z direction. The illustrated inclined surface 72 is inclined stepwise and includes a plurality of surfaces with different inclination angles. Specifically, the inclined surface 72 includes a first inclined surface 72A corresponding to the second surface M12 of the virtual surface M and a second inclined surface 72B corresponding to the third surface M13 of the virtual surface M. Further, the surface 71 includes a circular central surface 73 continuous with the inner side in the radial direction of the inclined surface 72 and an outer edge surface 74 which is an annular surface continuous with the outer side in the radial direction of the inclined surface 72. The central surface 73 corresponds to a ground surface ground in the grinding process. The outer edge surface 74 corresponds to the fourth surface M14 of the virtual surface M. In such a semiconductor device 11K, it is possible to secure a wider effective area of the device. Note that the semiconductor device 111K is not limited to the case including the inclined surface 72, and may include an inclined surface and / or an inclined curved surface according to the aspect of the virtual surface M instead of the inclined surface 72.

[0092] In the above-described embodiment, as shown in FIG. 16, a radiation cutting step (peripheral portion processing step) of forming a modified region 12 by irradiating laser light L along a radial line 5h which is a processing line extending radially from the inner side to the outer side in the peripheral portion E may be provided. The setting of the radial line 5h can be performed in the GUI9. The radial line 5h is a virtual line. The radial line 5h may be specified by coordinates. The radial line 5h is a radiation cut planned line for planning the formation of a modified region by the radiation cutting step. The radial line 5h extends linearly (radially) along the radial direction of the object 11 when viewed from the laser light incident surface. In the illustrated example, a plurality of radial lines 5h are set so that the peripheral portion E is equally divided (here, into four parts) in the circumferential direction when viewed from the Z direction.

[0093] The radial cutting process is a process of performing processing for separating the unnecessary portion to be removed by trimming. For example, in the radial cutting process, after the second laser processing step and before the peeling step, with the stage 2 not rotated, in a state where the condensing position is positioned on the radial line 5h in the object 11, under AF tracking control, the start and stop of the irradiation of the laser beam L in the laser processing head 3 are controlled, and the condensing position of the laser beam L is moved along the radial line 5h. This laser processing is repeatedly performed for all the radial lines 5h, whereby one or a plurality of modified regions 12 are formed in the Z direction along the radial lines 5h. According to such a radial cutting process, it becomes possible to surely peel the peripheral portion E.

[0094] In the above embodiment, when the virtual plane M includes a plurality of planes, the processing order of the laser processing for these plurality of planes is not particularly limited and may be arbitrary. In the above embodiment, the index direction is not particularly limited and may be a direction from the inner side in the radial direction toward the outer side in the radial direction, or may be a direction from the outer side in the radial direction toward the inner side in the radial direction, or these directions may be appropriately combined according to the situation.

[0095] In the above embodiment, the type of the object 11, the shape of the object 11, the size of the object 11, the number and direction of the crystal orientations of the object 11, and the plane orientation of the main surface of the object 11 are not particularly limited. In the above embodiment, the vicinity of the back surface 11b includes, for example, positions close to the back surface 11b, positions near the back surface 11b, positions around the back surface 11b, etc., and may also include positions on the back surface 11b and positions overlapping the back surface 11b.

[0096] In the above-described embodiment, the front surface 11a of the object 11 is used as the laser light incident surface, but the back surface 11b of the object 11 may be used as the laser light incident surface. In the above-described embodiment, the modified region 12 may be, for example, a crystal region, a recrystallized region, or a gettering region formed inside the object 11. The crystal region is a region that maintains the structure of the object 11 before processing. The recrystallized region is a region that solidifies as a single crystal or polycrystal when it solidifies again after once evaporating, being turned into plasma, or melting. The gettering region is a region that exhibits a gettering effect of collecting and capturing impurities such as heavy metals, and may be formed continuously or intermittently. The above-described embodiment may be applied to processing such as ablation.

[0097] Each configuration in the above-described embodiment and modification is not limited to the above-described materials and shapes, and various materials and shapes can be applied. Further, each configuration in the above-described embodiment or modification can be arbitrarily applied to each configuration in other embodiments or modifications.

Description of Reference Numerals

[0098] 5... processing line, 5a... parallel line, 5h... radial line, 11... object (first substrate, second substrate), 11a... front surface (main surface), 11b... back surface (main surface), 11Z... removal region, 12, 12a, 12b, 12c... modified region, 12s... modified spot, 111... object, 161... first device layer, 162... second device layer, E... peripheral portion, H11, H12... peeling surface, J, J2, J3, J4, J5, J6, J7... connection portion, L... laser light, M... virtual surface, M11, M21, M51... first surface, M12... second surface (first part), M32, M42, M52, M62, M72... second surface, M13... third surface (first part), R... main body portion, θ1, θ21, θ31, θ41, θ51... first angle, θ2, θ32, θ42, θ52... second angle, θ3... third angle.

Claims

1. An object processing method for processing an object, comprising: a laser processing step of forming a modified region along a virtual surface inside the object by irradiating the object with a laser beam; the object has a surface, and a part on the surface side is a removal region; the virtual surface includes a first surface extending in a direction intersecting the surface, and a second surface connected to the opposite side of the surface side on the first surface via a connection portion and extending in a direction intersecting the first surface; in a cross-sectional view intersecting the surface, a first angle formed by the first surface and the second surface, and a second angle formed by the surface and the second surface are obtuse angles; the first angle is smaller than the second angle; the connection portion is provided in the removal region of the object, object processing method.

2. after the laser processing step, a peeling step of peeling a part of the object with the modified region across the virtual surface as a boundary; after the laser processing step, a removing step of removing the removal region of the object, the object processing method according to claim 1.

3. the removing step removes the removal region by grinding, the object processing method according to claim 2.

4. the virtual surface includes a third surface connected to the opposite side of the surface side on the second surface and extending in a direction intersecting the second surface; in a cross-sectional view intersecting the surface, a third angle formed by the second surface and the third surface is an obtuse angle; the first angle is smaller than the third angle, the object processing method according to claim 1 or 2.

5. the object includes a peripheral portion located at the periphery and a main body portion inside the peripheral portion when viewed from a direction facing the surface; the first surface is formed inside the object along the boundary between the peripheral portion and the main body portion of the object, the object processing method according to claim 1 or 2.

6. a peripheral portion processing step of irradiating the laser beam along a radial line extending radially from the inside to the outside of the peripheral portion to form the modified region, the object processing method according to claim 5.

7. the object has a first substrate and a second substrate; a first device layer is formed on the main surface of the first substrate; a second device layer is formed on the main surface of the second substrate; The object processing method according to claim 1 or 2, wherein the first substrate and the second substrate are joined via the first device layer and the second device layer.

8. The laser processing step is as follows: A first laser processing step of irradiating the laser light under a first processing condition along at least a first portion of the virtual surface to form the modified region; After the first laser processing step, a second laser processing step of irradiating the laser light under a second processing condition along the virtual surface to form the modified region; and The first processing condition is a condition under which a plurality of cracks included in the modified region are intermittently connected; The second processing condition is a condition under which a plurality of cracks included in the modified region formed by the first and second laser processing steps are connected to each other after the second laser processing step and extend over the entire area of the virtual surface. The object processing method according to claim 1 or 2.

Images