Object processing method and object processing system

Abstract

This invention relates to a method and system for processing an object. The object processing method includes: a grinding step, grinding a portion of an object from its surface to a predetermined grinding position; and a laser processing step, forming one or more rows of modified regions along a line prior to the grinding step. The laser processing step includes: a data acquisition step, acquiring measurement data related to the displacement of a laser incident surface; a focusing step, based on the measurement data, adjusting the focusing position of the laser to follow the displacement of the laser incident surface; and a monitoring step, whereby, when the focusing position follows the displacement of the laser incident surface based on the measurement data, monitoring in the optical axis direction of the focusing lens whether the modified region formed by focusing the laser towards the focusing position exceeds an error detection position determined between the predetermined formation position of the modified region closest to the predetermined grinding position and the predetermined grinding position on the side of the predetermined grinding position.

Description

Technical Field

[0001] This invention relates to a method and system for processing objects. Background Technology

[0002] A known object processing method comprises: a grinding step, which grinds a portion of the object from its surface to a predetermined grinding position; and a laser processing step, prior to the grinding step, irradiating the object with a laser along a line via a focusing lens, thereby forming a modified region along the line between the object's internal surface and the predetermined grinding position (see, for example, Japanese Patent Application Laid-Open No. 2009-131942). In the laser processing step of this object processing method, the focusing position of the laser, which is focused inside the object, is moved along a line and follows the displacement of the laser incident surface. Summary of the Invention

[0003] In the technology described above, when the laser focusing position (hereinafter also simply referred to as the "focusing position") follows the laser incident surface, the focusing position may locally shift significantly in the optical axis direction of the focusing lens due to factors such as vibration, unevenness, reflectivity changes, and cracks in the object. In this case, a modified region may form in the object that exceeds the predetermined grinding position on the side opposite to the surface (i.e., the portion not removed by grinding), and this modified region remains in the object after grinding. As a result, the quality of the object deteriorates after grinding. Furthermore, below, "exceeding" (moving) on ​​the side opposite to the surface will also be simply referred to as "exceeding".

[0004] Therefore, the purpose of this invention is to provide a method and system for processing objects that can suppress residual modified areas in the object after grinding.

[0005] An object processing method according to one aspect of the present invention includes: a grinding step, grinding a portion of an object from its surface to a predetermined grinding position; a laser processing step, prior to the grinding step, irradiating the object with a laser along a line via a focusing lens, forming one or more rows of modified regions along the line between the internal surface of the object and the predetermined grinding position, the laser processing step including: a data acquisition step, acquiring measurement data related to the displacement of the laser incident surface of the object; a focusing step, moving the focusing position of the laser along the line while irradiating the displacement of the laser incident surface by the focusing position based on the measurement data; and a monitoring step, when the focusing position follows the displacement of the laser incident surface based on the measurement data, monitoring in the optical axis direction of the focusing lens whether the modified region formed by the laser focusing at the focusing position exceeds an error detection position determined between the predetermined formation position of the modified region closest to the predetermined grinding position and the predetermined grinding position on the side of the predetermined grinding position.

[0006] In this object processing method, when the focusing position follows the displacement of the laser incident surface, it is monitored whether the modified area formed by focusing light onto this focusing position exceeds an erroneous detection position determined on the surface side closer to the predetermined grinding position. Therefore, if the monitoring result indicates that the modified area exceeds the erroneous detection position, processing can be performed, for example, to prevent the focusing position from approaching the predetermined grinding position, so that the modified area does not exceed the predetermined grinding position. That is, it is possible to suppress the presence of a residual modified area on the object after grinding.

[0007] In one aspect of the object processing method of the present invention, during the monitoring step, when the focusing position is moved to follow the laser incident surface based on measurement data, a detour amount corresponding to the offset in the optical axis direction when the position of the modified region formed by the laser focusing at the focusing position deviates from the predetermined formation position of the modified region, is calculated, and it is monitored whether the detour amount exceeds the distance in the optical axis direction from the predetermined formation position to the error detection position. In this case, the detour amount can be used to monitor whether the modified region exceeds the error detection position on the grinding predetermined position side.

[0008] In one aspect of the object processing method of the present invention, the measurement data may also be a voltage value corresponding to the reflected light obtained by a sensor that receives the reflected light of a ranging laser reflected from a laser incident surface. In this case, it is possible to use a sensor that receives the reflected light of a ranging laser reflected from a laser incident surface to monitor whether the modified area exceeds the error detection position on the grinding predetermined position side.

[0009] In one aspect of the object processing method of the present invention, the monitoring step may also include the following steps: moving the focusing lens along the optical axis direction by feedback control in such a way that the measured data becomes a target voltage value, so that the focusing position follows the displacement of the laser incident surface; and, as a result of the feedback control, monitoring whether the modified region exceeds the error detection position on the grinding predetermined position side based on the difference between the voltage value obtained by the sensor (i.e., the voltage value after feedback) and the target voltage value. In this case, a sensor that receives the reflected light of the ranging laser reflected from the laser incident surface can be effectively used to monitor whether the modified region exceeds the error detection position on the grinding predetermined position side.

[0010] In one aspect of the object processing method of the present invention, the laser processing step may also include an input step in which an error detection position is input via an input unit. In this case, the user can set the desired error detection position via the input unit.

[0011] In one aspect of the object processing method of the present invention, in the focusing process, if the focusing position along the line is located in an error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the position of the focusing lens in the optical axis direction can be fixed. In this case, it is possible to specifically process the process so that the modified region does not exceed the grinding predetermined position.

[0012] In one aspect of the object processing method of the present invention, in the focusing process, if the focusing position along the line direction is in an error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the control parameters related to the following of the focusing position can be changed to make the following sluggish. In this case, it is possible to specifically process the process so that the modified region does not exceed the grinding predetermined position.

[0013] In one aspect of the object processing method of the present invention, during the focusing process, if the focusing position along the line is located in an error region where the modified area exceeds the error detection position on the grinding predetermined position side during the monitoring process, the laser irradiation of the object can be stopped. In this case, it is possible to specifically perform processing such that the modified area does not exceed the grinding predetermined position.

[0014] In one aspect of the object processing method of the present invention, an error display may be shown on the display unit when, during the monitoring process, it is determined that the modified area exceeds the error detection position on the grinding predetermined position side. In this case, by displaying the error on the display unit, the user can be notified, for example, that there is a high probability that a modified area remains on the object after grinding.

[0015] An object processing system according to one aspect of the present invention comprises: a grinding apparatus for grinding a portion of an object from its surface to a predetermined grinding position; a laser processing apparatus for irradiating the object with a laser along a line via a condenser lens before grinding is performed by the grinding apparatus, thereby forming one or more rows of modified regions along a line between the internal surface of the object and the predetermined grinding position; the laser processing apparatus further comprises: a support for supporting the object; an irradiation unit for irradiating the object with a laser via a condenser lens; a moving mechanism for moving at least one of the support and the irradiation unit to move the focusing position of the laser; an actuator for driving the condenser lens along the optical axis direction; a measurement data acquisition unit for acquiring measurement data related to the displacement of the laser incident surface in the object; and a control unit for controlling... The irradiation unit, the moving mechanism, and the actuator, along with the control unit, perform focusing and monitoring processes. In the focusing process, at least one of the support unit and the irradiation unit is moved along a line so that the focusing position of the laser moves along the line. Simultaneously, based on measurement data, at least one of the support unit and the focusing lens is moved along the optical axis so that the focusing position follows the displacement of the laser incident surface. In the monitoring process, when at least one of the support unit and the focusing lens is moved along the optical axis based on measurement data so that the focusing position follows the displacement of the laser incident surface, the system monitors whether the modified region formed by the laser focusing at the focusing position exceeds the error detection position determined between the formation predetermined position of the modified region closest to the grinding predetermined position and the grinding predetermined position on the grinding predetermined position side.

[0016] In this object processing system, when the focusing position follows the displacement of the laser incident surface, it is monitored whether the modified area formed by focusing light onto that focusing position exceeds an erroneous detection position closer to the surface side than the predetermined grinding position. Therefore, if the monitoring result indicates that the modified area exceeds the erroneous detection position, processing can be performed, for example, to prevent the focusing position from approaching the predetermined grinding position, so that the modified area does not exceed the predetermined grinding position. Thus, it is possible to suppress the presence of a residual modified area on the object after grinding. Attached Figure Description

[0017] Figure 1 This is a structural diagram illustrating the object processing system of the implementation method.

[0018] Figure 2 It means Figure 1 A structural diagram of a laser processing head.

[0019] Figure 3(a) shows Figure 1 Figure 3(b) shows an example of the input / output screen of the GUI of a laser processing device. Figure 1 An example diagram of the input / output screen of the GUI of a grinding device.

[0020] Figure 4 It is a cross-sectional view of the object used to illustrate the location of the error detection.

[0021] Figure 5(a) is a top view showing the object used to explain the object processing method of the embodiment. Figure 5(b) is a cross-sectional view showing the object of Figure 5(a).

[0022] Figure 6(a) is a subsequent top view of Figure 5(a) showing the object processing method of the embodiment. Figure 6(b) is a cross-sectional view showing the object of Figure 6(a).

[0023] Figure 7(a) is a subsequent top view of Figure 6(a) showing the object processing method of the embodiment. Figure 7(b) is a cross-sectional view showing the object of Figure 7(a).

[0024] Figure 8 This is a subsequent cross-sectional view of FIG7(a), which illustrates the object processing method of the implementation method.

[0025] Figure 9 This is a flowchart illustrating the trimming process in the implementation method.

[0026] Figure 10 This is a diagram illustrating an example of the monitoring results of the monitoring process in the implementation method.

[0027] Figure 11(a) is a top view of the object undergoing the cutting process in a modified example. Figure 11(b) is a top view of the object following Figure 11(a).

[0028] Figure 12(a) is a top view of the object undergoing the peeling process in a modified example. Figure 12(b) is a top view of the subsequent object in Figure 12(a). Detailed Implementation

[0029] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts are labeled with the same symbols in each drawing, and repeated descriptions are omitted.

[0030] like Figure 1 As shown, the object processing system 101 is a system for processing object 100, and includes a laser processing device 1, an object conveying mechanism 40, and a grinding device 60.

[0031] [Laser processing equipment]

[0032] The laser processing apparatus 1 is a device that forms modified regions on the object 100 by irradiating it with a laser beam at a focal point (at least a portion of the focal area, or the focal point) aligned with the object 100. Prior to grinding by the grinding apparatus 60, the laser processing apparatus 1 irradiates the object 100 with a laser beam along the line for forming the predetermined modified regions, forming one or more rows of modified regions along the line inside the object 100. The laser processing apparatus 1 performs cutting and radial cutting processes on the object 100. Cutting is a process used to remove unwanted portions from the object 100. Radial cutting is a process used to separate the unwanted portions removed by the cutting process. In this embodiment, the X and Y directions are horizontal directions, and the Z direction is a vertical direction.

[0033] As shown in Figure 5, the object 100 includes a first substrate 100T, a functional element layer 112, and a second substrate 100B. The first substrate 100T, the functional element layer 112, and the second substrate 100B are arranged in a stacked manner according to this sequence. The first substrate 100T and the second substrate 100B are wafers formed in a circular plate shape. The first substrate 100T and the second substrate 100B are, for example, semiconductor substrates such as silicon substrates, piezoelectric material substrates formed of piezoelectric materials, and glass substrates formed of glass. Cutouts or orientation planes indicating the crystal orientation may also be provided on the first substrate 100T and the second substrate 100B.

[0034] The functional element layer 112 includes multiple functional elements. These functional elements are, for example, wiring components, light-receiving elements such as photodiodes, light-emitting elements such as laser diodes, and circuit elements such as memory. These functional elements can be constructed in three dimensions by stacking multiple layers or arranged in a matrix. Here, the functional element layer 112 includes multiple metal layers and multiple non-metal layers. The metal layers include Ti (titanium) layers and Sn (tin) layers. The non-metal layers include, for example, oxide film layers and nitride film layers. The non-metal layer 12b includes, for example, SiO (silicon monoxide) layers and SiCN (silicon carbon nitride) layers.

[0035] A line (loop line) M1 is provided on the object 100 as a predetermined cutting line. Line M1 is a line that is predetermined based on the formation of the modified area based on the cutting process. Line M1 extends in a loop on the inner side of the outer edge of the object 100. Here, line M1 extends in a circular loop. Line M1 is set at the boundary between the removal area E removed by the cutting process and the effective area R inside it. The setting of line M1 can be performed in the GUI (Graphical User Interface) 9 described below. Line M1 is an imaginary line, but it can also be an actually drawn line. Line M1 can also be a line specified by coordinates. The explanation related to the setting of line M1 is also the same in the description of lines M2, M4, and M5 below.

[0036] As shown in Figure 6, a line (straight line) M2 is set on the object 100 as a predetermined line for radial cutting. Line M2 is a line that is predetermined to form a modified region based on the radial cutting process. Viewed from the laser incident surface, line M2 extends in a straight line (radially) along the radial direction of the object 100. Viewed from the laser incident surface, multiple lines M2 are set in such a way that they equally divide the removal region E circumferentially (here, it is divided into four parts).

[0037] like Figure 1 As shown, the laser processing apparatus 1 includes a stage 7, a laser processing head 10A, a Z-axis rail 22, a Y-axis rail 24, an imaging unit 25, a GUI 9, and a control unit 8. The stage 7 is a support for the object 100. The stage 7 is configured to rotate about an axis parallel to the Z-direction. The object 100 is placed on the stage 7. The stage 7 is driven to rotate by the driving force of a known drive device such as an electric motor.

[0038] like Figure 1 and Figure 2 As shown, the laser processing head 10A irradiates the object 100 placed on the stage 7 with laser L1 along the Z direction via the focusing section 14, forming a modified region inside the object 100. The laser processing head 10A can move linearly in the Z direction along the Z-axis rail 22 by the driving force of a known drive device such as an electric motor. The laser processing head 10A can also move linearly in the Y direction along the Y-axis rail 24 by the driving force of a known drive device such as an electric motor. The laser processing head 10A constitutes an irradiation section. The focusing section 14 includes a focusing lens.

[0039] like Figure 2 As shown, the laser processing head 10A includes a frame 11, an incident section 12, an adjustment section 13, and a focusing section 14. The incident section 12 directs laser L1, output from a light source (not shown), into the frame 11. The light source outputs laser L1, which is transmissible relative to the object 100, through, for example, pulse oscillation. The adjustment section 13 is disposed within the frame 11. The adjustment section 13 adjusts the laser L1 incident from the incident section 12. Each structure of the adjustment section 13 is mounted on an optical substrate 29 disposed within the frame 11. The optical substrate 29 is integral with the frame 11.

[0040] The adjustment unit 13 includes an attenuator 31, a beam expander 32, a mirror 33, a reflective spatial light modulator 34, and an imaging optical system 35. The attenuator 31 adjusts the output of the laser L1 incident from the incident section 12. The beam expander 32 amplifies the diameter of the laser L1 output by the attenuator 31. The mirror 33 reflects the laser L1 whose diameter has been amplified by the beam expander 32. The reflective spatial light modulator 34 modulates the laser L1 reflected by the mirror 33. The reflective spatial light modulator 34 is, for example, a spatial light modulator (SLM) of a reflective liquid crystal on silicon (LCOS). The imaging optical system 35 is a telecentric optical system on both sides of the reflecting surface 34a of the reflective spatial light modulator 34 and the entrance pupil surface 14a of the focusing section 14, positioned in an imaging relationship. The imaging optical system 35 consists of three or more lenses.

[0041] The focusing unit 14 is arranged to pass through the hole 26a formed in the lower wall of the frame 11. The focusing unit 14 focuses the laser L1, which is adjusted by the adjustment unit 13, and emits it out of the frame 11.

[0042] In the laser processing head 10A, laser L1 is incident from the incident section 12 into the frame 11 and travels in parallel. After being reflected sequentially by the mirror 33 and the reflective spatial light modulator 34, it is emitted from the focusing section 14 out of the frame 11. Furthermore, the arrangement order of the attenuator 31 and the beam expander 32 can be reversed. Additionally, the attenuator 31 can be positioned between the mirror 33 and the reflective spatial light modulator 34. Furthermore, the adjustment section 13 can also have other optical components (e.g., a steering mirror positioned before the beam expander 32).

[0043] The laser processing head 10A also includes a dichroic mirror 15, a range sensor 16, an observation section 17, an actuator 18, and a circuit section 19. The dichroic mirror 15 is disposed between the imaging optical system 35 and the focusing section 14. The dichroic mirror 15 allows the laser L1 to pass through. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 is preferably cubic or composed of two plates arranged in a twisted relationship.

[0044] The range sensor 16 is a sensor that illuminates the laser incident surface of the object 100 with a range-measuring laser L10 and receives the reflected light from the laser incident surface. The range sensor 16 acquires information related to the received reflected light as measurement data related to the displacement (including concavity, convexity, and tilt) of the laser incident surface of the object 100. The measurement data is displacement data. For example, the measurement data is a voltage value corresponding to the received reflected light. Since the range sensor 16 is coaxial with the laser L100, astigmatic sensors can be used. Furthermore, if the range sensor is not coaxial with the laser L100, triangulation, laser confocal, white confocal, beam splitting interferometry, and astigmatic sensors can be used as the range sensor 16. There are no particular limitations on the type of range sensor 16; various sensors can be used. Furthermore, as a range sensor 16 coaxial with the laser L1, a triangulation method sensor utilizing the eccentricity of the range-measuring laser L10 and its reflected light from the focusing section 14 can be used. The range sensor 16 constitutes a measurement data acquisition unit.

[0045] The observation unit 17 outputs observation light L20 to the laser incident surface of the object 100 and detects the observation light L20 reflected from the laser incident surface. That is, the observation light L20 output from the observation unit 17 is irradiated onto the laser incident surface via the focusing unit 14, and the observation light L20 reflected from the laser incident surface is detected by the observation unit 17 via the focusing unit 14. The wavelengths of the laser L1, the ranging laser L10, and the observation light L20 are different from each other (at least their center wavelengths are offset from each other).

[0046] Actuator 18 is mounted on optical substrate 29. Actuator 18, for example, moves focusing section 14 along the optical axis direction of laser L1, i.e., the Z direction, by the driving force of a piezoelectric element. Circuit section 19, for example, consists of multiple circuit boards. Circuit section 19 processes signals output from range sensor 16 and signals input to reflective spatial light modulator 34. Circuit section 19 controls actuator 18 based on signals output from range sensor 16. Circuit section 19 and control section 8 (see reference) Figure 1 Electrical connection.

[0047] The circuit unit 19 drives the actuator 18 based on the measurement data acquired by the range sensor 16, causing the focusing unit 14 to follow the laser incident surface. For example, the range sensor 16 acquires a voltage value as measurement data, and drives the actuator 18 in such a way that this voltage value becomes the target voltage value, performing feedback control to move the focusing unit 14 in the Z direction. This causes the focusing position to follow the displacement of the laser incident surface. The target voltage value is the voltage value that serves as the reference (target) for driving the focusing unit 14 to follow the laser incident surface, and is based on the voltage value acquired by the range sensor 16 at the height set below. Hereinafter, the control of driving the focusing unit 14 to follow the laser incident surface will also be referred to as AF (autofocus) tracking control. In AF tracking control, the focusing unit 14 is moved along the Z direction based on the displacement data in a manner that maintains a constant distance between the laser incident surface of the object 100 and the focusing position of the laser L1.

[0048] The circuit section 19 stores (acquires) the drive voltage value (control command value) of the drive actuator 18 to make the focusing section 14 follow the laser incident surface. In addition, the control section 8 or other circuit sections may also have the function of following the drive actuator 18 and storing the drive voltage value.

[0049] Back Figure 1 Z-axis rail 22 is a rail extending along the Z direction. Z-axis rail 22 is mounted to laser processing head 10A via mounting part 21. Z-axis rail 22 moves laser processing head 10A along the Z direction, thereby moving the focusing position of laser L1 along the Z direction. Y-axis rail 24 is a rail extending along the Y direction. Y-axis rail 24 is mounted to Z-axis rail 22 via mounting part 23. Y-axis rail 24 moves laser processing head 10A along the Y direction, thereby moving the focusing position of laser L1 along the Y direction. Z-axis rail 22 and Y-axis rail 24 constitute a moving mechanism. Hereinafter, the focusing position of laser L1 using focusing part 14 will be simply referred to as the "focusing position".

[0050] The imaging unit 25 images the object 100 from the direction of incident along the laser L1. The imaging unit 25 includes an alignment camera AC and an imaging unit IR. The alignment camera AC and the imaging unit IR are mounted together with the laser processing head 10A on the mounting unit 21. The alignment camera AC uses light transmitted through the object 100 to image a device pattern, for example. The image obtained is used to align the laser L1 with the irradiation position of the object 100.

[0051] The imaging unit IR captures images of the object 100 using light transmitted through it. For example, if the object 100 is a silicon wafer, near-infrared light is used in the imaging unit IR. The imaging unit IR includes a light source, an objective lens, and a light detection unit. The light source outputs light that is transmissive to the object 100. The light source may be, for example, a halogen lamp and a filter, and outputs near-infrared light. The light output from the light source is guided by an optical system such as a mirror and passes through the objective lens to illuminate the object 100. The objective lens allows light reflected from a surface of the object 100 opposite to the laser incident surface to pass through. That is, the objective lens allows light propagating (transmitted) within the object 100 to pass through. The objective lens has a correction ring. The correction ring corrects aberrations caused by light within the object 100 by adjusting the distance between the multiple lenses constituting the objective lens, for example. The light detection unit detects the light transmitted through the objective lens. The light detection unit may be, for example, an InGaAs camera, and detects near-infrared light. The imaging unit IR is capable of capturing images of at least one of the modified region formed inside the object 100 and the cracks extending from the modified region. In the laser processing apparatus 1, the imaging unit IR can be used to confirm the processing status of the laser processing in a non-destructive manner.

[0052] The control unit 8 is configured as a computer device including a processor, memory, storage devices, and communication equipment. In the control unit 8, software (programs) loaded into the memory are executed by the processor, and the processor controls the reading and writing of data from the memory and storage devices, as well as communication via the communication equipment. The control unit 8 controls the various parts of the laser processing apparatus 1 to perform various functions.

[0053] The control unit 8 controls at least the stage 7, the laser processing head 10A, the movement of the laser processing head 10A along the Z-axis rail 22, and the movement of the laser processing head 10A along the Y-axis rail 24. The control unit 8 controls the rotation of the stage 7, the irradiation of the laser L1 from the laser processing head 10A, and the movement of the focusing position of the laser L1. Based on rotation information (hereinafter also referred to as "θ information") related to the amount of rotation of the stage 7, the control unit 8 can perform various controls. The θ information can be obtained from the drive amount of the drive device that rotates the stage 7, or it can be obtained through other sensors, etc. The θ information can be obtained using various known methods.

[0054] While rotating the stage 7 and positioning the focusing position on line M1 of the object 100, the control unit 8, under AF follow control, controls the start and stop of laser L1 irradiation in the laser processing head 10A based on θ information, thereby performing a cutting process to form a modified region along line M1. The cutting process is the operation performed by the control unit 8 that realizes the cutting process.

[0055] In a state where the stage 7 is not rotated and the focusing position is located on line M2 of the object 100, the control unit 8 controls the start and stop of the irradiation of the laser L1 in the laser processing head 10A under AF follow control, and moves the focusing position of the laser L1 along line M2, thereby performing a radiographic cutting process to form a modified region along line M2. The radiographic cutting process is the process performed by the control unit 8 to realize the radiographic cutting process.

[0056] The formation and cessation of the modified region can be switched as follows. For example, in the laser processing head 10A, the formation and cessation of the modified region can be switched by switching the start and stop (ON / OFF) of the irradiation (output) of the laser L1. Specifically, when the laser oscillator is a solid-state laser, the start and stop of the irradiation of the laser L1 can be quickly switched by switching the Q-switch (AOM (acousto-optic modulator), EOM (electro-optic modulator), etc.) installed in the resonator. When the laser oscillator is a fiber laser, the start and stop of the irradiation of the laser L1 can be quickly switched by switching the output of the semiconductor laser that constitutes the seed laser and the amplifier (excitation) laser. When the laser oscillator uses an external modulation element, the start and stop of the irradiation of the laser L1 can be quickly switched by switching the external modulation element (AOM, EOM, etc.) installed outside the resonator.

[0057] Alternatively, the formation and cessation of the modified region can be achieved as follows: For example, the optical path of laser L1 can be opened and closed by controlling a mechanical mechanism such as a gate, switching between the formation and cessation of the modified region. The formation of the modified region can also be stopped by switching laser L1 to CW (continuous wave) light. The formation of the modified region can also be stopped by displaying a pattern (e.g., a pear-skin pattern of laser scattering) on ​​the liquid crystal layer of the reflective spatial light modulator 34 that indicates a state where the focused state of laser L1 cannot be modified. Alternatively, the output of laser L1 can be reduced by controlling an output adjustment unit such as an attenuator to prevent the formation of the modified region, thereby stopping its formation. The formation of the modified region can also be stopped by switching the polarization direction. The formation of the modified region can also be stopped by scattering (scattering) laser L1 in a direction other than the optical axis to cut the light.

[0058] The GUI9 displays various information. The GUI9 may include, for example, a touch panel display. Users input various settings related to processing conditions into the GUI9 through touch and other operations. The GUI9 constitutes an input unit that receives input from the user.

[0059] Figure 3(a) shows an example of the input / output screen of GUI9. Figure 3(a) shows an example of four rows of modified regions being formed inside the object 100. In Figure 3(a), SD1, SD2, SD3, and SD4 represent modified regions that move away from the laser incident surface in this order (approaching the predetermined grinding position in this order). The Z-height corresponds to the predetermined position for the formation of the modified regions. The Z-height is defined as a value (0) relative to the laser incident surface, and its value increases as it moves from the laser incident surface into the interior of the object 100. The predetermined position for the formation of the modified regions is represented, for example, by Z-height × DZ rate ± α. The DZ rate is a pre-set value. α is a correction value corresponding to the settings of various processing conditions and is a value determined empirically. The output corresponds to the output of laser L1 when the modified regions are formed.

[0060] In GUI9, users can input the Z-height, output, and detailed conditions for SD1 through SD4 respectively. Additionally, in GUI9, users can input the following error detection location T2 (refer to...). Figure 4 The Z-height of SD1 and the predetermined position T1 for the formation of the modified region 4T closest to the predetermined grinding position (refer to...) Figure 4 Corresponding to. The conditions set by the laser processing apparatus 1 are set based on the final thickness of the first substrate 100T.

[0061] [Object conveying mechanism]

[0062] The object transport mechanism 40 is a mechanism for transporting the object 100 processed by the laser processing apparatus 1 to the grinding apparatus 60. The object transport mechanism 40 includes an arm 41 capable of holding the object 100, a slider 42 disposed at the base end of the arm 41, and a rail 43 for moving the slider 42 horizontally. The structure of the object transport mechanism 40 is not particularly limited; various known structures can be used as long as the object 100 can be transported between the laser processing apparatus 1 and the grinding apparatus 60.

[0063] The object transport mechanism 40 includes a control unit 48 and a GUI 49. The control unit 48 is configured as a computer device including a processor, memory, storage devices, and communication equipment. In the control unit 48, software loaded into the memory is executed by the processor, and the processor controls the reading and writing of data from the memory and storage devices, as well as communication via the communication equipment. The control unit 48 controls various parts of the object transport mechanism 40 to perform various functions. The GUI 49 displays various information. The GUI 49 may include, for example, a touch panel display. Various settings related to transport conditions are input into the GUI 49 through user touch or other operations.

[0064] [Grinding device]

[0065] The grinding apparatus 60 is an apparatus for grinding the object 100 processed by the laser processing apparatus 1. The grinding apparatus 60 grinds the object 100 from surface 100a to a predetermined grinding position T3 (see reference 1). Figure 4 The grinding apparatus 60 includes a grinding wheel 61 capable of high-speed rotation, a base 62 rotatably supporting the grinding 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 100 to be ground, and a platform 67 for placing the object 100 to be ground. The platform 67 is configured to rotate about an axis parallel to the vertical direction.

[0066] The grinding apparatus 60 includes a control unit 68 and a GUI 69. The control unit 68 is configured as a computer device including a processor, memory, storage devices, and communication equipment. In the control unit 68, software loaded into memory is executed by the processor, and the processor controls the reading and writing of data from the memory and storage devices, as well as communication via the communication equipment. The control unit 68 controls various parts of the grinding apparatus 60 to perform various functions. The GUI 69 displays various information. The GUI 69 may include, for example, a touch panel display. Various settings related to grinding conditions are input into the GUI 69 through user touch or other operations.

[0067] Figure 3(b) shows an example of the input / output screen of GUI 69. In the figure, the thickness before processing is the thickness H1 of the object 100 before grinding performed by the grinding device 60 (see reference). Figure 4 The finished thickness is the thickness H2 of the object 100 after grinding by the grinding device 60 (refer to...). Figure 4 The stage speed is the rotational speed of the stage 67 during grinding performed by the grinding apparatus 60. The grinding wheel speed is the rotational speed of the grinding wheel 61 during grinding performed by the grinding apparatus 60. In the GUI 69, the user can input the thickness before processing, the finished thickness, the stage speed, the grinding wheel speed, and detailed conditions. The conditions set by the grinding apparatus 60 are based on the final thickness of the first substrate 100T.

[0068] The main parts of this embodiment will be further explained.

[0069] The circuit section 19 and control section 8 of the laser processing apparatus 1 perform cutting (focusing) processing, radial cutting processing, and monitoring processing. In the cutting process, the laser processing head 10A focuses the laser L1 inside the object 100, and while rotating the stage 7 to move the focusing position of the laser L1 along line M1, AF tracking control is performed to make the focusing position follow the displacement of the surface 100a, which is the laser incident surface. In the radial cutting process, the laser processing head 10A focuses the laser L1 inside the object 100, and while moving at least one of the stage 7 and the laser processing head 10A to move the focusing position of the laser L1 along line M2, AF tracking control is performed to make the focusing position follow the displacement of the surface 100a, which is the laser incident surface.

[0070] If laser L1 is focused inside the object 100, the laser L1 will be particularly absorbed in the region corresponding to the focusing position, forming a modified region inside the object 100. The modified region is a region whose density, refractive index, mechanical strength, and other physical properties differ from the surrounding unmodified region. Examples of modified regions include, for instance, melt-processed regions, cracked regions, insulation breakdown regions, and regions with refractive index changes.

[0071] If an object 100 is irradiated with a laser L1 output via pulse oscillation, and the focusing position of the laser L1 moves relative to lines M1 and M2 set on the object 100, multiple modified particles are formed in a row along lines M1 and M2. A modified particle is formed by irradiation with a single pulse of laser L1. A row of modified regions is a collection of multiple modified particles arranged in a row. Adjacent modified particles may be connected or separated depending on the relative movement speed of the laser L1 relative to the focusing position of the object 100 and the repetition frequency of the laser. The shapes of the set lines M1 and M2 can also be lattice-like, ring-like, straight, curved, or combinations thereof.

[0072] In the AF tracking control of the cutting process, the monitoring process monitors whether the modified region 4 formed by the focusing of laser L1 towards the focusing position exceeds the error detection position T2 (refer to the grinding predetermined position T3 in the Z direction) on the side of the grinding predetermined position T3. Figure 4 ).like Figure 4As shown, the error detection position T2 is a position determined between the formation predetermined position T1 and the grinding predetermined position T3 of the modified region 4T closest to the grinding predetermined position. The formation predetermined position T1 is the position where the predetermined modified region 4T is formed. The formation predetermined position T1 can be based on one end of the modified region 4T on the grinding predetermined position T3 side. The error detection position T2 corresponds to the value of the error detection position input to the user via GUI9. The error detection position T2 can also be set at the middle position between the formation predetermined position T1 and the grinding predetermined position T3. The error detection position T2 can also be a value automatically determined based on the grinding predetermined position T3.

[0073] In the monitoring process, the detour amount of the AF following control is calculated, and it is monitored whether the calculated detour amount exceeds the distance in the Z direction from the predetermined formation position T1 to the error detection position T2 (hereinafter also referred to as the "detour tolerance range"). Thus, the AF following control monitors whether the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side. In the monitoring process, if it is determined that the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side, an error display is shown on the GUI9. In this case, the GUI9 constitutes a display unit. In the monitoring process, information indicating that the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side can also be output to the outside of the laser processing apparatus 1. The detour amount corresponds to the Z-direction offset of the position of the modified region 4 formed by the focusing of the laser L1 under AF following control from the predetermined formation position of the modified region 4. The detour amount can be expressed, for example, by the following formula.

[0074] Detour amount = AF differential signal × rate

[0075] The AF differential signal is the difference between the target voltage value and the voltage value obtained by the ranging sensor 16 as a result of AF tracking control, i.e., the feedback voltage value. The rate is a preset parameter. Furthermore, when high-precision tracking of the focusing position based on AF tracking control is achieved, the feedback voltage value is the target voltage value (in this case, the AF differential signal = 0). On the other hand, when high-precision tracking of the focusing position based on AF tracking control cannot be achieved for some reason, the feedback voltage value becomes a value offset from the target voltage value (in this case, the AF differential signal ≠ 0).

[0076] That is, in the monitoring process, the actuator 18 is used to perform feedback control to move the focusing part 14 in the Z direction by using the measured data as the target voltage value, so that the focusing position follows the displacement of the laser incident surface. In the monitoring process, based on the feedback control result, the difference between the feedback voltage value and the target voltage value (AF differential signal) obtained by the ranging sensor 16 is used to monitor whether the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side.

[0077] During the cutting process, the focusing position along line M1 is located in the error region when the modified region 4T in the monitoring process exceeds the error detection position T2 on the side of the predetermined grinding position T3 (refer to...). Figure 10 In the case of a fixed actuator 18, the driving voltage value of the actuator 18 is fixed (it is its previous voltage value and does not change), and the position of the focusing part 14 in the Z direction is fixed.

[0078] Next, an example of an object processing method for processing object 100 using object processing system 101 will be described.

[0079] First, a laser processing step is performed in the laser processing apparatus 1. That is, as shown in Figures 5(a) and 5(b), the object 100 is placed on the stage 7 with surface 100a set as the laser incident surface side. Next, a cutting process is performed. In the cutting process, the cutting process is executed by the control unit 8 based on the processing conditions input via GUI9. In the cutting process, while the stage 7 is rotated at a certain rotational speed and the focusing position is located on line M1, the start and stop of the irradiation of the laser L1 in the laser processing head 10A is controlled based on θ information under AF follow control. As a result, as shown in Figures 6(a) and 6(b), a modified region 4 is formed along line M1 inside the first substrate 100T of the object 100. Here, four rows of modified regions 4 are formed in the Z direction inside the object 100. The formed modified regions 4 include modified points and cracks C extending from the modified points.

[0080] Next, radial cutting is performed. In radial cutting, the control unit 8 executes the process based on the processing conditions input via GUI9. During radial cutting, without rotating the stage 7, laser L1 is irradiated from the laser processing head 10A, and under AF follow-up control, the laser processing head 10A is moved along the Y-axis rail 24, causing the focusing position to move along line M2. After rotating the stage 7 by 90 degrees, without rotating the stage 7, laser L1 is irradiated from the laser processing head 10A, and under AF follow-up control, the laser processing head 10A is moved along the Y-axis rail 24, causing the focusing position to move along line M2. This forms one or more rows of modified regions 4 along line M2. The formed modified regions 4 include modified points and cracks extending from the modified points. Then, as shown in Figures 7(a) and 7(b), the modified regions 4 are used as boundaries by, for example, a jig or air, to cut and remove the removal area E.

[0081] Next, based on the transport conditions input via GUI49, the object 100 is transported from the laser processing apparatus 1 to the grinding apparatus 60 via the object transport mechanism 40. Then, based on the grinding conditions input via GUI69, the grinding apparatus 60 performs the grinding process. That is, as... Figure 8 As shown, based on the measurement results of the object thickness gauge 66, the grinding wheel 61 grinds the object 100 from surface 100a to the predetermined grinding position T3 (refer to the reference). Figure 4 The portion of the material was ground. As a result, a semiconductor device 100K was obtained (manufactured).

[0082] Next, refer to Figure 9 The flowchart details the cutting process.

[0083] First, in the GUI9 of the laser processing apparatus 1, information related to the predetermined formation positions of each of the multiple modified regions 4 is input and set. This is related to the predetermined grinding position T3 (refer to...). Figure 4 Information related to the predetermined position of the modified region 4T on the side is set so that the modified region 4T is located on the side closer to the surface 100a than the predetermined grinding position T3 (step S1). At this time, the extension amount of the crack C and the aforementioned tortuous allowable range are taken into consideration. At the same time, in the GUI9 of the laser processing apparatus 1, the error detection position is input and set (step S2: input process).

[0084] Furthermore, while the settings in GUI9 are based on the settings of GUI69 of the grinding device 60 and are input by the user, they can also be automatically set based on information input via communication or the like. Additionally, when information related to the settings of GUI69 of the grinding device 60 is input via communication or the like, the settings in GUI9 can also be input by the user under guidance and restrictions based on that information.

[0085] As an example, the position closest to the predetermined grinding location T3 (refer to...) Figure 4 The predetermined formation position of the modified region 4T on the first substrate 100T side is set such that the distance from the lower end of the modified region 4T (to the main surface of the second substrate 100B side of the first substrate 100T) exceeds the finished thickness of the first substrate 100T, which is 50 μm. Considering the tortuosity tolerance of AF follow-up control and the extension amount of crack C, the predetermined formation position of the modified region 4T is set such that the distance from the lower end of the modified region 4T is 65 μm. Under this setting, the allowable tortuosity is 15 μm, which is the difference between the predetermined formation position of the modified region 4T (lower end distance 65 μm) and the finished thickness of the first substrate 100T, which is 50 μm. An error detection position is set within this range. For example, an error detection position is set at the position where a tortuosity of 12 μm or more occurs.

[0086] Next, based on an image of the laser incident surface of the object 100 acquired, for example, by the imaging unit 25, the control unit 8 moves the laser processing head 10A along the Z direction, so that the focusing position is located on the laser incident surface, and the focusing unit 14 is moved along the Z direction. This alignment of the focusing unit 14 relative to the laser incident surface is called "height setting," and the position of the focusing unit 14 at this time is called the height setting position. In the height setting, the focusing position can be aligned with line M1 on the laser incident surface of the object 100, or it can be aligned with the center portion of the laser incident surface of the object 100.

[0087] Next, AF tracking control is performed before the cutting process to acquire measurement data and AF differential signals (step S3: data acquisition and monitoring process). In step S3, without irradiating the laser L1 from the laser processing head 10A, the voltage value as measurement data is acquired by the range sensor 16 while the stage 7 is rotated. Furthermore, in step S3, the actuator 18 is driven by the circuit unit 19 to perform feedback control, i.e., AF tracking control, which moves the focusing unit 14 along the Z direction to follow the displacement of the laser incident surface, with the voltage value acquired by the range sensor 16 as the target voltage value. Additionally, in step S3, the voltage value acquired by the range sensor 16 as a result of this AF tracking control is acquired by the circuit unit 19 in association with the position information (here, position θ) of the object 100, i.e., the feedback voltage value. Then, in step S3, the difference between the target voltage value and the acquired feedback voltage value, i.e., the AF differential signal, is calculated. The AF differential signal is stored in the control unit 8 or the circuit unit 19.

[0088] In AF follow-up control, it is monitored whether a detour exceeding the modified region 4T beyond the error detection position T2 occurs (step S4: monitoring process). In step S4, the detour amount during AF follow-up control is calculated based on the differential signal. In step S4, it is monitored whether the calculated detour amount exceeds the distance in the Z direction from the predetermined position T1 to the error detection position T2, i.e., the detour tolerance range.

[0089] If the monitoring result in step S4 indicates that a detour exceeding the error detection position T2 has occurred, an error message is displayed on GUI9 (in step S5, step S6). The error message is not particularly limited; it can warn of a detour exceeding the error detection position T2. ​​In addition to the error message, an audio signal can also be output from GUI9.

[0090] Following step S6 above, the error region is the area within which the focusing position is located at a detour of position θ that exceeds the error detection position T2 (see reference). Figure 10During the process, a cutting process including AF tracking control with a fixed drive voltage value of actuator 18 is performed (step S7: focusing process). That is, in step S7, a cutting process including AF tracking control (fixing the drive voltage value of actuator 18) is performed. In the AF tracking control of step S7, specifically, the actuator 18 is driven by the circuit section 19 in such a way that the voltage value used as the measurement data becomes the target voltage value, so that the focusing section 14 moves along the Z direction to track the displacement of the laser incident surface, and if the focusing position along the direction of line M1 is in an incorrect region, the drive voltage value of actuator 18 is fixed at the drive voltage value at position θ directly in front of the incorrect region. In step S7, if the θ position of the focusing position is in an incorrect region, the position of the focusing section 14 in the Z direction is fixed.

[0091] On the other hand, if the monitoring result of step S4 above determines that no detour exceeding the error detection position T2 has occurred, a cutting process including normal AF follow control (fixed drive voltage value of actuator 18) is performed (no in step S5, step S8: focusing process).

[0092] Figure 10 This is a chart illustrating an example of the monitoring results of a monitoring process. In Figure 10 The diagram shows the detour amount associated with the θ position of the focusing position, the predetermined formation position T1 of the modified region 4T, the error detection position T2, and the predetermined grinding position T3. Figure 10 In this diagram, the θ position of the focusing point is used as the horizontal axis, and the vertical axis represents the various data. Figure 10 For ease of explanation, regardless of the position θ of the focusing position, the predetermined position T1, the error detection position T2, and the grinding predetermined position T3 are set to be constant.

[0093] exist Figure 10 In the example shown, regarding the θ position of the focusing position, the detour amount increases from θ1 to θ2 until it exceeds the error detection position T2 on the downward side (grinding predetermined position T3 side). This focusing position θ position, in the region between θ1 and θ2, is an error region, which is the region of the focusing position along the direction of line M1 when the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side in step S4. In this embodiment, in the error region, the drive voltage value of the actuator 18 is fixed and set to a constant, the position of the focusing part 14 in the Z direction is fixed and set to a constant, the focusing position does not follow the surface 100a, and the detour amount is set to a constant.

[0094] In the object processing method and object processing system 101, during AF tracking control to make the focusing position follow the displacement of the laser incident surface, it is monitored whether the modified region 4T formed by focusing light onto the focusing position exceeds the erroneous detection position T2 (on the surface 100a side) that is closer to the predetermined grinding position T3. Therefore, if the monitoring result determines that the modified region 4T exceeds the erroneous detection position T2, processing can be performed, for example, to prevent the focusing position from approaching the predetermined grinding position T3, so that the modified region 4T does not exceed the predetermined grinding position T3. That is, it is possible to suppress the presence of a residual modified region 4T on the object 100 after grinding.

[0095] In AF tracking control, overshoot (sudden changes) can sometimes occur in the voltage value of the ranging sensor 16 and / or the drive voltage value of the actuator 18 due to various locally generated factors (e.g., vibration of the stage 7, unevenness of the laser incident surface, changes in the reflectivity of the film on the laser incident surface, cracks in the laser incident surface, etc.). In this embodiment, unnecessary overshoot can be predicted and avoided. Damage such as cracks in the second substrate 100B during removal of the removal area E before the grinding process can be suppressed. Quality deterioration of the object 100 after cutting can be suppressed.

[0096] In the object processing method, the measured data is the voltage value corresponding to the reflected light acquired by the ranging sensor 16. In this case, the ranging sensor 16 can be used to monitor whether the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side.

[0097] In the object processing method, the monitoring step includes a step of performing AF tracking control to make the focusing position follow the displacement of the laser incident surface, and a step of monitoring whether the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side based on the difference between the feedback voltage value and the target voltage value obtained by the ranging sensor 16 (AF differential signal) as a result of the AF tracking control. In this case, the ranging sensor 16 can be effectively used to monitor whether the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side.

[0098] In the object processing method, during the monitoring step, the detour amount of the AF following control is calculated, and it is monitored whether the detour amount exceeds the distance in the Z direction from the predetermined position T1 to the error detection position T2. ​​In this case, the detour amount can be used to monitor whether the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side.

[0099] Furthermore, in the monitoring process, the measured data can be used directly for monitoring without calculating the detour amount of the AF follow-up control, so as not to leave the modified region 4T remaining on the polished object 100. Specifically, in the AF follow-up control, it is also possible to monitor whether the AF differential signal exceeds the voltage value corresponding to the distance from the predetermined position T1 to the error detection position T2. ​​In this case, the ranging sensor 16 can be used efficiently to monitor whether the modified region 4T exceeds the error detection position T2 on the polishing predetermined position T3 side.

[0100] In the object processing method, the laser processing step includes an input step where an error detection position T2 is input via GUI9. In this case, the user can set the desired error detection position T2 via GUI9.

[0101] In the object processing method, during the focusing process, if the focusing position along line M1 is in an incorrect region, the focusing position in the Z direction is fixed. In this case, it is possible to specifically process the process so that the modified region 4 does not exceed the predetermined grinding position T3.

[0102] In the object processing method, during the monitoring process, if it is determined that the modified region 4T exceeds the error detection position T2 on the grinding predetermined position T3 side, an error display is shown on the GUI9. In this case, by displaying the error on the GUI9, the user can be notified, for example, that the modified region 4T remains on the ground object 100, or that there is a high probability of it.

[0103] The present invention is not limited to the embodiments described above.

[0104] In the above-described embodiments and variations, when the focusing position along the direction of line M1 is in an incorrect region during the cutting process, the drive voltage value of the actuator 18 in the AF follow-control is fixed, and the focusing part (focusing lens) 14 in the Z direction is fixed, but this is not limited to this. For example, when the focusing position along the direction of line M1 is in an incorrect region during the cutting process, the voltage value used as measurement data can also be fixed. Furthermore, when the focusing position along the direction of line M1 is in an incorrect region during the cutting process, the irradiation of the laser L1 onto the object 100 can be stopped. In this case, it is also possible to specifically ensure that the modified region 4T does not exceed the predetermined grinding position T3.

[0105] Alternatively, for example, in the cutting process, if the focusing position along the direction of line M1 is in the wrong region, the control parameters involved in the focusing position following in the AF following control can be changed to make the following sluggish. Specifically, the change in control parameters here can also be to reduce the gain of the control parameters of the PID control implemented by the AF following control, increase the proportional band, and increase at least one of these, so that the drive voltage value of actuator 18 does not overshoot (change drastically). In this case, it is also possible to specifically process the process so that the modified region 4T does not exceed the predetermined grinding position T3.

[0106] Furthermore, in AF tracking control, since it is sometimes sufficient to track the slow displacement of the laser incident surface (e.g., about 2μm / 10mm), even if the actuator 18 is fixed or driven sluggishly to make the tracking sluggish, it is not a problem to improve the quality, because it is sometimes sufficient to track the rapid displacement of the laser incident surface caused by foreign objects (e.g., 2μm / 0.1mm).

[0107] Alternatively, for example, in the cutting process, if the focusing position along the direction of line M1 is in an incorrect area, it is also possible to control the focusing part 14 to move a predetermined distance closer to the surface 100a. In this case, it is also possible to specifically ensure that the modified region 4T does not exceed the predetermined grinding position T3.

[0108] In the above embodiments and variations, the AF tracking control in the cutting process monitors whether the modified region 4T exceeds the error detection position T2, but is not limited thereto. For example, the AF tracking control in the radial cutting process can also monitor whether the modified region exceeds the error detection position. In the above embodiments and variations, various processes are performed in the cutting process to ensure that the modified region 4T does not exceed the error detection position T2, but is not limited thereto. For example, various processes can also be performed in the radial cutting process to ensure that the modified region 4T does not exceed the error detection position T2.

[0109] In the above-described embodiments and variations, radial cutting is performed after the cutting process, but it is not limited to this. For example, in the above-described embodiments and variations, a cutting process (cutting process) can also be performed after the cutting process and before the grinding process to form a modified region within the effective area R along lines extending in a grid pattern. Specifically, as shown in Figures 11(a) and 11(b), a modified region 4 can also be formed in the effective area R along a straight line M4 after the cutting process. Multiple lines M4 are provided on the object 100. Multiple lines M4 are provided in at least a grid pattern in the effective area R. In this case, the modified region can be monitored in the AF follow-up control during the cutting process to see if it exceeds the error detection position. Various processes can also be performed during the cutting process to ensure that the modified region does not exceed the error detection position.

[0110] Alternatively, for example, a peeling process (peeling step) can be performed after the cutting process and before the grinding process. Specifically, as shown in Figures 12(a) and 12(b), a modified region 4 can be formed along a line M5 on an imaginary surface inside the object 100 after the cutting process. The line M5 is set in the effective region R. The line M5 extends in a spiral shape with the center position of the object 100 as the center. In this case, the modified region can be monitored in the AF follow-up control during the peeling process to ensure that it does not exceed the error detection position. Various treatments can also be performed during the peeling process to ensure that the modified region does not exceed the error detection position.

[0111] In the above embodiments and modifications, the voltage value corresponding to the reflected light received by the ranging sensor 16 is used as the measurement data. However, there are no particular limitations as long as the measurement data is related to the displacement of the laser incident surface, and such measurement data can be obtained using various known techniques. The measurement data can also be the voltage value obtained by a ranging sensor that is set along the optical axis of the laser L1. In this case, the obtained voltage value can be processed in the same way as the voltage value of the ranging sensor 16 described above. The measurement data can also be data related to the position of the movable part of the actuator 18. If a sensor capable of measuring the surface shape of the laser incident surface of the object 100 is used, data related to the detection result of that sensor can also be used as the measurement data. The measurement data can also be the absolute position of the focusing part 14 in the Z direction. The measurement data can also be the relative position of the focusing part 14 in the Z direction relative to its position when set at a certain height.

[0112] In the above-described embodiments and variations, the detour amount can be calculated solely based on the measurement data without acquiring the AF differential signal. Specifically, it is also possible to monitor whether the displacement of the laser incident surface at each moving distance (moving time) from the focusing position generates a displacement exceeding the driving capability of the actuator 18, and calculate the excess displacement as the detour amount. As an example, when processing with the moving distance of the focusing position set to 300 mm / s, if the actuator 18 is equipped with a driving capability capable of following a displacement of 2 μm at a moving distance of 10 mm, it can be set such that if the displacement of the laser incident surface is 4 μm at a moving distance of 10 mm, then the detour amount can generate at least about 2 μm (approximately 2 μm × speed (4 in this case) = 8 μm in the object 100). In this case, since the possibility of overshoot is also considered, the possibility of overshoot can be further considered, and it is possible to monitor whether the modified region 4T exceeds the error detection position T2.

[0113] In the above-described embodiments and modifications, the driving voltage value of the actuator 18 (the position of the movable part of the actuator 18) and the displacement of the laser incident surface can be used to monitor whether the modified region 4T exceeds the error detection position T2. ​​For example, in this case, the value of the driving voltage value of the actuator 18 converted into the Z-direction movement of the focusing part 14 (focusing position) and the value of the displacement of the laser incident surface can be compared, and the modified region 4T can be monitored based on the comparison result to see if it exceeds the error detection position T2.

[0114] In the above-described embodiments and modifications, the difference between the drive voltage value of the actuator 18 and the current position of the movable part of the actuator 18 can also be used to monitor whether the modified region 4T exceeds the error detection position T2. ​​In the above-described embodiments and modifications, the overshoot shape generated by the drive voltage value of the actuator 18 and the current position of the movable part of the actuator 18 can also be used to monitor whether the modified region 4T exceeds the error detection position T2.

[0115] In the above embodiments and modifications, the surface 100a of the object 100 is used as the laser incident surface, but other surfaces of the object 100 can also be used as laser incident surfaces. In the above embodiments and modifications, the modified region 4 can be, for example, a crystalline region, a recrystallized region, or a gettering region formed inside the object 100. A crystalline region is a region that maintains the structure of the object 100 before processing. A recrystallized region is a region that solidifies into a single crystal or polycrystalline form after evaporation, plasma treatment, or melting and then solidification. A gettering region is a region that performs the gettering effect by collecting and capturing impurities such as heavy metals; it can be formed continuously or intermittently. Furthermore, the laser processing apparatus 1 can also be applied to processes such as ablation.

[0116] In the above-described embodiments and modifications, the moving mechanism can be configured to move at least one of the stage 7 and the laser processing head 10A. In the above-described embodiments and modifications, the θ position is used as the position information, but it can be replaced by, or at least one of the following, such as the time and coordinate information from the start of laser processing, can be used as the position information. The position information is simply data indicating the location of the object 100 on its circumference. In the above-described embodiments and modifications, the height setting performed after the cutting process is omitted, but this height setting can also be included.

[0117] In the above-described embodiments and variations, AF tracking control is performed separately from the cutting process (focusing process) in step S3 to acquire measurement data, but this is not a limitation. For example, so-called real-time processing can also be performed during the cutting process (focusing process) while irradiating laser L1 and simultaneously acquiring measurement data through AF tracking control.

[0118] In the above-described embodiments and variations, in the monitoring process, in addition to monitoring whether the modified region 4T closest to the predetermined grinding position T3 exceeds the error detection position T2, it is also possible to monitor whether the modified region 4 other than the modified region 4T exceeds the error detection position T2. ​​In this case, in the focusing process, the various processes described above can also be performed based on the monitoring results in the monitoring process to ensure that the modified region 4 other than the modified region 4T does not exceed the error detection position T2.

[0119] The structures in the above-described embodiments and modifications are not limited to the materials and shapes described above, and various materials and shapes can be used. Furthermore, the structures in the above-described embodiments and modifications can be arbitrarily applied to structures in other embodiments or modifications.

[0120] According to the present invention, a method and system for processing an object can be provided that can be monitored to prevent the presence of modified areas in the object after grinding.

Claims

1. A method for processing an object, wherein, have: The grinding process involves grinding the portion of an object from its surface to a predetermined location. In the laser processing step, prior to the grinding step, a laser beam is irradiated onto the object along a line via a focusing lens, forming one or more rows of modified regions along the line between the object's internal surface and the predetermined grinding position. The laser processing steps include: The data acquisition process involves acquiring measurement data related to the displacement of the laser incident surface of the object. In the focusing process, the focusing position of the laser is moved along the line while the focusing position follows the displacement of the laser incident surface based on the measurement data. In the monitoring process, when the focusing position is made to follow the displacement of the laser incident surface based on the measurement data, in the optical axis direction of the focusing lens, it is monitored whether the modified region formed by the laser focusing to the focusing position exceeds the error detection position determined between the formation predetermined position of the modified region closest to the grinding predetermined position and the grinding predetermined position on the grinding predetermined position side.

2. The object processing method according to claim 1, wherein, In the monitoring process, Based on the measured data, when the focusing position is made to follow the displacement of the laser incident surface, the detour amount corresponding to the offset in the optical axis direction is calculated when the position of the modified region formed by the laser focusing at the focusing position is offset from the predetermined position for the formation of the modified region. Monitor whether the detour amount exceeds the distance along the optical axis from the predetermined position to the error detection position.

3. The object processing method according to claim 1, wherein, The measurement data is obtained by a sensor that receives the reflected light of a range-measuring laser reflected from the laser incident surface, and the voltage value corresponding to the reflected light is obtained from the reflected light.

4. The object processing method according to claim 2, wherein, The measurement data is obtained by a sensor that receives the reflected light of a range-measuring laser reflected from the laser incident surface, and the voltage value corresponding to the reflected light is obtained from the reflected light.

5. The object processing method according to claim 3, wherein, The monitoring process includes: Feedback control is performed to move the condenser lens along the optical axis by using the measured data as the target voltage value, so that the focusing position follows the displacement of the laser incident surface. As a result of the feedback control, based on the difference between the feedback voltage value (which is the voltage value acquired by the sensor) and the target voltage value, it is monitored whether the modified region exceeds the error detection position on the grinding predetermined position side.

6. The object processing method according to claim 4, wherein, The monitoring process includes: Feedback control is performed to move the condenser lens along the optical axis by using the measured data as the target voltage value, so that the focusing position follows the displacement of the laser incident surface. As a result of the feedback control, based on the difference between the feedback voltage value (which is the voltage value acquired by the sensor) and the target voltage value, it is monitored whether the modified region exceeds the error detection position on the grinding predetermined position side.

7. The object processing method according to any one of claims 1 to 6, wherein, The laser processing step includes an input step in which the error detection location is input via an input unit.

8. The object processing method according to any one of claims 1 to 6, wherein, In the concentration process, When the focusing position along the line is in an error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the position of the focusing lens in the optical axis direction is fixed.

9. The object processing method according to claim 7, wherein, In the concentration process, When the focusing position along the line is in an error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the position of the focusing lens in the optical axis direction is fixed.

10. The object processing method according to any one of claims 1 to 6, wherein, In the concentration process, If the focusing position along the direction of the line is in an error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the control parameters involved in following the focusing position are changed to make the following sluggish.

11. The object processing method according to claim 7, wherein, In the concentration process, If the focusing position along the direction of the line is in an error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the control parameters involved in following the focusing position are changed to make the following sluggish.

12. The object processing method according to any one of claims 1 to 6, wherein, In the concentration process, If the focusing position along the direction of the line is in the error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the laser irradiation of the object shall be stopped.

13. The object processing method according to claim 7, wherein, In the concentration process, If the focusing position along the direction of the line is in the error region where the modified region exceeds the error detection position on the grinding predetermined position side during the monitoring process, the laser irradiation of the object shall be stopped.

14. The object processing method according to any one of claims 1 to 6, wherein, During the monitoring process, if it is determined that the modified area exceeds the error detection position on the grinding predetermined position side, an error display is shown on the display unit.

15. The object processing method according to claim 7, wherein, During the monitoring process, if it is determined that the modified area exceeds the error detection position on the grinding predetermined position side, an error display is shown on the display unit.

16. An object processing system, wherein, have: A grinding apparatus, comprising the portion of an object to be ground from its surface to a predetermined grinding position; A laser processing apparatus, prior to grinding by the grinding apparatus, irradiates a laser along a line through a condenser lens onto the object, forming one or more rows of modified regions along the line between the object's internal surface and the predetermined grinding position. The laser processing device has: Support portion, which supports the object; An irradiation unit that irradiates the object with the laser light via the focusing lens; A moving mechanism that moves at least one of the support and the irradiation part to move the focusing position of the laser. An actuator that drives the condenser lens along the optical axis of the condenser lens; The measurement data acquisition unit acquires measurement data related to the displacement of the laser incident surface in the object. The control unit controls the irradiation unit, the moving mechanism, and the actuator. The control unit performs focusing and monitoring processes. In the focusing process, while moving at least one of the support and the irradiation part along the line to move the focusing position of the laser along the line, based on the measurement data, at least one of the support and the focusing lens is moved along the optical axis to make the focusing position follow the displacement of the laser incident surface. In the monitoring process, when at least one of the support and the condenser lens is moved along the optical axis direction based on the measurement data so that the focusing position follows the displacement of the laser incident surface, in the optical axis direction, it is monitored whether the modified region formed by the laser focusing to the focusing position exceeds the erroneous detection position determined between the formation predetermined position of the modified region closest to the grinding predetermined position and the grinding predetermined position.

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