Laser processing device for SiC ingot

Abstract

The present invention relates to a laser processing device for SiC ingots, comprising a workpiece carrier, a focusing lens, a moving unit, a Raman information acquisition unit, a focus height acquisition unit, a laser processing unit, and a control unit. The workpiece carrier and the focusing lens are respectively disposed at a moving end of the moving unit. The moving path of the focusing lens passes through the projection light paths of the Raman information acquisition unit, the focus height acquisition unit, and the laser processing unit. The moving unit, the Raman information acquisition unit, the focus height acquisition unit, and the laser processing unit are each communicatively connected to the control unit to achieve focusing of the projection light passing through the focusing lens on the workpiece surface layer and the modified layer on the workpiece carrier. The present invention achieves non-destructive and precise measurement of small facet areas based on Raman detection, thereby assisting in controlling the subsequent laser processing process. The device has the advantages of a compact structure, high production efficiency and quality, improved processing consistency, and reduced material loss in the modified layer.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device processing, and in particular to a laser processing device for SiC crystal ingots. Background Art

[0002] Semiconductor materials, resistant to high temperatures and radiation, with wide band gaps and high breakdown electric fields, are becoming the primary substrates for electronic devices, holding significant application prospects in fields such as communications and defense. Among the multiple steps involved in converting an ingot into a qualified substrate wafer, ingot slicing is a major source of material loss. Currently, the main ingot slicing technologies include wire sawing and laser lift-off (LAS). Compared to traditional wire sawing, laser lift-off offers the advantages of high production efficiency and minimal material consumption, making it a promising candidate for development. Laser lift-off (LAS) focuses a laser at a predetermined depth within the semiconductor material, creating a large modified area before wafer separation. However, during the ingot growth process, varying doping concentrations (carrier concentrations) create faceted and non-faceted regions with varying resistivity, refractive index, and energy absorption. When the modified laser passes through these faceted and non-faceted regions, the depth of its focus varies, resulting in low flatness in the resulting wafer and significant losses during subsequent polishing. Furthermore, this resistivity non-uniformity can lead to a significant mismatch between the silicon carbide substrate and the epitaxial layer grown on it. Therefore, accurate characterization of the ingot doping concentration is an important step in improving wafer production capacity and guiding subsequent processes.

[0003] The Chinese patent with the authorization announcement number CN110911268B discloses a laser processing device for forming a peeling layer in a SiC ingot, wherein the laser processing device comprises: a workpiece holding stage for holding the SiC ingot; a facet region detection unit for detecting the facet region from the upper surface of the SiC ingot held by the workpiece holding stage; a coordinate setting unit for setting the following two directions as the X-axis and the Y-axis respectively to set the X-coordinate and the Y-coordinate of the boundary between the facet region and the non-facet region; a laser light irradiation unit including a condenser for emitting a laser beam having a wavelength that is transparent to SiC. The laser beam is positioned at a focal point at a depth from the upper surface of the SiC ingot equivalent to the thickness of the wafer to be produced, and the SiC ingot is irradiated with laser beams to form a peeling layer that separates the SiC into Si and C and extends cracks along the c-plane; an X-axis feed mechanism; a Y-axis feed mechanism; and a control and information processing unit that increases the energy of the laser beam when irradiating the facet region and raises the position of the condenser based on the X-coordinate and Y-coordinate of the boundary between the facet region and the non-facet region, relative to the energy of the laser beam when irradiating the non-facet region. The above method uses a camera to capture the upper surface of the ingot and uses an image processing unit to binarize the captured image to distinguish between the facet region and the non-facet region. However, the ingot is relatively thick, and distinguishing between the facet region and the non-facet region by direct imaging is not easy, and errors are easily generated during implementation.

[0004] The Chinese patent publication number CN115472515A discloses a processing device for generating a plurality of wafers from an ingot, wherein the processing device comprises: a holding unit having a holding surface for holding the ingot; a fluorescence detection unit for irradiating the ingot with excitation light of a predetermined wavelength from above the ingot and detecting the number of photons of fluorescence generated from the upper surface of the ingot; a laser beam irradiation unit for positioning a focal point of a laser beam of a wavelength that is transparent to the ingot at a depth from the upper surface of the ingot corresponding to the thickness of the wafer to be generated and irradiating the ingot to form a peeling layer; and a moving unit for moving the holding unit and the focal point of the laser beam relative to the holding unit. The method comprises: a storage unit for storing the distribution of the number of fluorescence photons on the upper surface of the ingot detected by the fluorescence detection unit in association with the XY coordinate position on the XY plane parallel to the holding surface as two-dimensional data, and storing the height direction position of the ingot obtained from the two-dimensional data, i.e., the Z coordinate position, in association with the two-dimensional data; and a three-dimensional data generation unit for generating three-dimensional data showing the distribution of the number of fluorescence photons in the entire ingot based on the two-dimensional data of each Z coordinate position of the ingot stored in the storage unit. The above method utilizes a laser beam of a specific wavelength to irradiate the ingot and detects the intensity of the fluorescence light generated on the upper surface of the ingot to achieve the determination of the facet area. However, the laser power density used in the fluorescence detection step is relatively high, which can easily cause damage to the surface of the ingot.

[0005] Chinese patent publication number CN117316791A discloses a small facet detection device, which is characterized by including: an irradiation module for irradiating a first surface of a crystal ingot with a laser beam to generate a peeling layer on the crystal ingot; an acquisition module for applying ultrasonic waves to the formed crystal ingot based on an ultrasonic vibration component to obtain a wafer corresponding to the peeling layer; a detection module for emitting a detection beam to the wafer based on a light source of a specific wavelength and recording the light source emission intensity at a receiving point on the wafer; a comparison module for comparing the transmission intensity of the wafer with the light source emission intensity to obtain the transmittance of the wafer; a determination module for locating a small facet area in the wafer based on a preset transmittance threshold and the transmittance of the wafer, and determining position information corresponding to the small facet area; an update module for updating the laser processing conditions of a next wafer adjacent to the wafer using the position information corresponding to the small facet area as guidance information, and peeling the next wafer based on the laser processing conditions, wherein the laser processing conditions at least include a laser focus position and a laser power. The above method completes the detection of the first peeled wafer by comparing the transmission intensity of the wafer and the output intensity of the light source, and then optimizes the laser processing conditions of the next wafer based on the position information corresponding to the small area of ​​the previous wafer. Laser energy fluctuations or other types of damage on the wafer surface will affect the measurement results, and there is also the problem of insufficient detection accuracy. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide a SiC crystal ingot laser processing device in response to the above-mentioned deficiencies in the prior art. The device realizes non-destructive and precise measurement of small face areas based on Raman detection, thereby assisting in regulating subsequent laser processing processes. The device has the advantages of compact structure, high production efficiency and quality, improved processing consistency, and reduced loss of modified layer material.

[0007] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0008] A laser processing device for SiC ingots includes a workpiece carrier, a focusing objective lens, a moving unit, a Raman information acquisition unit, a focus height acquisition unit, a laser processing unit, and a control unit. The workpiece carrier and the focusing objective lens are respectively arranged at the moving end of the moving unit. The moving path of the focusing objective lens passes through the projection light paths of the Raman information acquisition unit, the focus height acquisition unit, and the laser processing unit. The moving unit, the Raman information acquisition unit, the focus height acquisition unit, and the laser processing unit respectively establish communication connections with the control unit to complete the focusing of the projection light passing through the focusing objective lens on the workpiece surface layer and the modified layer on the workpiece carrier.

[0009] Specifically, in the "laser processing device" of the present invention,

[0010] The "workpiece" specifically refers to a solid material used to manufacture semiconductor devices; non-limiting examples include silicon carbide standards with different doping concentrations n, semi-insulating or conductive silicon carbide ingots, etc. The surface layer is the top facet and non-facet regions of the workpiece corresponding to the focus of the Raman information acquisition unit and the focus height acquisition unit on the top surface of the workpiece, and the modified layer is the internal planar region of the workpiece determined by the laser processing unit focusing at a predetermined depth d of the workpiece.

[0011] The specific meaning of the "workpiece carrier" is a table surface for carrying and fixing the workpiece, which has sufficient hardness and precision to ensure the stability and position accuracy of the workpiece during the processing. The design of the workpiece carrier allows it to move in a predetermined direction, so that the Raman information acquisition unit and the focus height acquisition unit can obtain Raman data, image information and position information of different detection points on the surface layer of the workpiece, and facilitate the laser processing unit to accurately process different modified points on the modified layer of the workpiece;

[0012] The specific meaning of the "focusing objective lens" refers to a laser scanning focusing mirror used to focus the projection light emitted by the Raman information acquisition unit and the focusing height acquisition unit on the surface layer of the top surface of the workpiece, or to focus the projection light emitted by the laser processing unit on the modified layer of the predetermined depth d of the workpiece. Its focusing design can ensure that the projection light forms a precise focusing point at the predetermined position of the workpiece, and feeds back the reflected light on the workpiece to the Raman information acquisition unit and the focusing height acquisition unit to obtain the workpiece parameters.

[0013] Furthermore, the mobile unit includes an XY-axis driver, an XY-axis linear module, a Z-axis driver and a Z-axis linear module, the control unit, the XY-axis driver and the XY-axis linear module establish communication connections in sequence, the workpiece carrier is arranged at the mobile end of the XY-axis linear module, the control unit, the Z-axis driver and the Z-axis linear module establish communication connections in sequence, and the focusing objective lens is arranged at the mobile end of the Z-axis linear module.

[0014] Specifically, in the "mobile unit" of the present invention,

[0015] The specific meaning of the "Z axis" is a coordinate axis parallel to the height direction of the workpiece on the workpiece carrier and parallel to the light output direction of the projection light path;

[0016] The specific meaning of the "X axis" is a coordinate axis perpendicular to the Z axis and parallel to the workpiece modified layer on the workpiece carrier;

[0017] The specific meaning of the "Y axis" is the coordinate axis perpendicular to the plane where the Z axis and the X axis are located;

[0018] The specific meaning of the "driver" is the electronic device used to drive the linear module, which converts the electrical signal output by the control unit into a voltage or current signal suitable for the operation of the linear module;

[0019] The specific meaning of the "linear module" refers to a device used to support and guide moving parts and perform reciprocating linear motion in a given direction; non-limiting examples include rectangular coordinate robots, synchronous belt linear modules, screw linear modules, linear motor linear modules, etc.

[0020] Furthermore, the projection end of the Raman information acquisition unit, the projection end of the focus height acquisition unit, the projection end of the laser processing unit, and the focusing objective lens are sequentially arranged along the moving direction of the Z-axis linear module.

[0021] Furthermore, the Raman information acquisition unit includes a first laser generating module, a Raman detection module, an image acquisition module, and a detection optical path module. The light output end of the first laser generating module is directed toward the light input end of the detection optical path module. The detection ends of the Raman detection module and the image acquisition module are respectively directed toward the light output end of the detection optical path module. The projection optical path of the detection optical path module passes through the focusing objective lens.

[0022] Preferably, the first laser generating module is configured as a continuous laser. The laser wavelength of the continuous laser is 450-1000 nm, the laser detection power is adjustable from 0 to 500 mW, and the beam quality factor M is 2 <1.2, wavelength drift <10pm.

[0023] Preferably, the Raman detection module is configured as a high-resolution Raman spectrometer. The spectral resolution of the high-resolution Raman spectrometer is less than 2 cm -1 , the spectrum covers the range of 100~4000cm -1 It can meet the Raman spectroscopy detection needs of different workpieces, and has high detection sensitivity. It can obtain clear Raman spectroscopy information under low concentration or weak signals, thereby improving the accuracy and reliability of the detection results.

[0024] Preferably, the image acquisition module is configured as a CCD camera. The CCD camera has high resolution and high sensitivity, capable of capturing and transmitting clear image information in real time. Its sufficient number of pixels ensures clear image details. Its high sensitivity also enables good imaging even in low-light conditions. Furthermore, the CCD camera can be equipped with an illumination source to assist in dark-field or bright-field imaging, meeting the needs of different detection scenarios.

[0025] Preferably, the detection optical path module includes a first dichroic mirror, a second dichroic mirror, a reflector, a filter group, and a convex lens. The first dichroic mirror (the projection end of the Raman information acquisition unit) is arranged between the focusing objective lens and the image acquisition module, the second dichroic mirror is arranged between the first laser generation module and the first dichroic mirror, and the reflector, filter group, convex lens and Raman detection module are arranged in sequence on the beam splitting path of the second dichroic mirror on the side away from the first laser generation module.

[0026] Furthermore, the focus height acquisition unit includes a focus finding module and a focus optical path module, the light output end and the detection end of the focus finding module are respectively directed toward the focus optical path module, and the projection light path of the focus optical path module passes through the focus objective lens.

[0027] Preferably, the focus-finding module is configured as a line laser focus sensor. This line laser focus sensor features high precision and high speed, enabling it to quickly and accurately determine the focal position, thereby improving the focusing efficiency and accuracy of the entire unit. During the focus-finding process, the line laser focus sensor emits a line laser and receives the reflected light signal, determining the focal position based on changes in the intensity of the light signal. Its operating principle is based on optical triangulation. By measuring the focal range of the laser beam on the workpiece surface, combined with the known laser beam angle and workpiece surface characteristics, the height of the focusing objective lens corresponding to the focal point formed on the workpiece surface layer can be calculated, and then the control unit is used to control and achieve focus.

[0028] Preferably, the focusing optical path module includes a third dichroic mirror, and the third dichroic mirror (the projection end of the focus height acquisition unit) is arranged between the focusing objective lens and the first dichroic mirror. The focusing optical path module is arranged on the beam splitting path on the side of the third dichroic mirror away from the first dichroic mirror.

[0029] Furthermore, the laser processing unit includes a second laser generating module, a laser power monitoring module, and a processing optical path module, the light output end of the second laser generating module is toward the light input end of the processing optical path module, and the light input ends of the laser power monitoring module and the focusing objective lens are respectively toward the light output end of the processing optical path module.

[0030] Preferably, the second laser generating module is configured as a pulsed laser, wherein the pulsed laser has a laser pulse width of 200 fs to 10 ns, a laser wavelength of 400 to 1100 nm, and a laser energy of 0.01 to 1500 mJ.

[0031] Preferably, the laser power monitoring module is configured as a high-precision optical power meter. This high-precision optical power meter can monitor the laser power during laser processing in real time, ensuring the stability and accuracy of the laser power. By monitoring the laser power in real time, abnormal fluctuations in laser power can be detected promptly, thereby avoiding quality issues during the laser processing process. Furthermore, the high-precision optical power meter has high sensitivity and high resolution, enabling precise measurement of even minute changes in laser power, providing strong support for precise control of laser processing.

[0032] Preferably, the processing optical path module includes a fourth dichroic mirror and a fifth dichroic mirror, the fourth dichroic mirror (the projection end of the laser processing unit) is arranged between the focusing objective lens and the first dichroic mirror, the fifth dichroic mirror is arranged between the second laser generating module and the fourth dichroic mirror, and the laser power monitoring module is arranged on the beam splitting path on the side of the fifth dichroic mirror away from the fourth dichroic mirror.

[0033] Furthermore, the control unit includes a data processing module and a control module, and the data processing module and the control module are communicatively connected;

[0034] The XY-axis driver, the first laser generating module, the Raman detection module, and the image acquisition module are respectively connected to the control module, and the data processing module associates the Raman characteristic peak frequency, image information, and the corresponding XY coordinate position of the focus point to complete the construction of the doping concentration distribution map of the surface layer of the workpiece and the power distribution map of the modified layer of the workpiece;

[0035] The Z-axis driver and the focus search module respectively establish communication connections with the control module, and the data processing module associates the Z-axis coordinate position of the focusing lens with the corresponding XY coordinate position of the focus point to complete the construction of the morphology distribution map of the surface layer of the workpiece;

[0036] The XY axis driver, Z axis driver, second laser generating module and laser power monitoring module respectively establish communication connections with the control module so that the workpiece and the focal point on the workpiece carrier can move relative to each other approximately in the XY direction and form a modified layer on the workpiece.

[0037] Specifically, the control process of the laser processing device is as follows:

[0038] S1 establishes a communication connection between the data processing module and the control module, and configures the XY axis driver and the Z axis driver in the control module;

[0039] S2 provides a workpiece on the workpiece carrier. The control module sends detection instructions to the XY axis driver and the first laser generating module in turn. The workpiece carrier moves to the position according to the predetermined Raman detection scanning path, and the first laser beam passing through the focusing objective lens is focused on the surface layer of the workpiece. The Raman detection module obtains the Raman characteristic peak frequency ω at different focus points on the surface layer of the workpiece. i The image acquisition module obtains the detection image of the workpiece, and the XY axis linear module feedbacks the XY coordinate position of the focus point (X i , Y j ), the data processing module determines the doping concentration n based on the Δω-n linear model ij , and these doping concentrations n ij , the detection image, and the corresponding XY coordinate position to construct the doping concentration distribution map of the workpiece surface layer (X i , Y j , n ij );

[0040] Among them, the fitting function of the Δω-n linear model is n=1.27×10 17 Δω (R=99%), specifically implemented by providing multiple silicon carbide standards with different doping concentrations n on the workpiece carrier, and the Raman detection module obtains the Raman characteristic peak frequency ω of these standards n The data processing module uses the Raman characteristic peak frequency ω of one of the standard samples n The difference calculation is performed based on the reference, and the relative Raman frequency shift Δω is determined, and then a Δω-n linear model of the relative Raman frequency shift Δω and the doping concentration n is established based on the least squares method;

[0041] The data processing module determines the laser processing power P at different focus points on the workpiece surface layer based on the doping concentration distribution map and the nP curve model between the preset doping concentration n and the laser processing power P. ij , and these laser processing powers P ij , the detection image, and the corresponding XY coordinate position to construct the power distribution map of the workpiece modified layer (X i , Y j , P ij ); Among them, the fitting function of the nP curve model is P=0.57e [n / (1.18×10^18)] (R=99%);

[0042] At the same time, the control module sends a focus command to the Z-axis driver and the focus module in turn. The Z-axis linear module feeds back the actual height of the focusing lens. The focus module obtains the focal range of the workpiece surface layer. The data processing module parses and generates the focal displacement information. The control module sends a focus command again. The focus lens moves to the position according to the predetermined focal displacement. The Z-axis linear module feeds back the Z-axis coordinate position (Z ij), the data processing module associates these focused Z-axis coordinate positions with the corresponding XY coordinate positions to construct a morphology distribution map of the workpiece surface layer (X i , Y j , Z ij );

[0043] The S3 control module sends processing instructions to the XY axis driver, Z axis driver and the second laser generation module (X i , Y j , n ij , P ij ), controls the focal point coordinate position, feed speed, feed direction and laser processing power, the workpiece carrier moves into position according to the predetermined laser processing scanning path, and the focusing objective lens moves into position according to the predetermined focal range displacement, so that the second laser beam passing through the focusing objective lens is focused on the predetermined depth d of the workpiece for internal modification, so as to complete the movement of the focal point approximately along the XY projection plane and perform laser modification on different areas of the modified layer of the workpiece.

[0044] Furthermore, it also includes a resistivity probe, which is installed at the mobile end of the mobile unit with the detection point facing the workpiece carrier, and the resistivity probe establishes a communication connection with the control unit to complete the resistivity detection of the workpiece surface layer on the workpiece carrier.

[0045] Furthermore, the resistivity probe is a contact resistivity probe, and the detection range of the resistivity probe is 0.1~100mΩ·cm, and the measurement accuracy is ≤0.5mΩ·cm.

[0046] Furthermore, the resistivity probe and focusing lens are mounted together or independently on the moving end of the Z-axis linear module. The resistivity probe and focusing lens can be mounted directly on the moving end of the Z-axis linear module to achieve joint control of the moving path, or they can be mounted separately on the moving end of the Z-axis linear module via a common transmission pair to achieve separate control of the moving path.

[0047] Furthermore, the XY-axis driver, Z-axis driver and resistivity probe respectively establish communication connections with the control module, so that the detection end of the resistivity probe contacts the workpiece surface of the workpiece carrier and performs resistivity detection on different areas of the workpiece surface layer.

[0048] Alternatively, the resistivity probe is a non-contact resistivity probe, and the detection range of the resistivity probe is 0.1-100 mΩ·cm, and the measurement accuracy is ≤0.5 mΩ·cm.

[0049] Furthermore, the XY-axis driver and the resistivity probe respectively establish communication connections with the control module, so that the detection end of the resistivity probe passes through the outside of the workpiece of the workpiece carrier and performs resistivity detection on different areas of the workpiece surface layer.

[0050] Specifically, the control process of the laser processing device is as follows:

[0051] S1 establishes a communication connection between the data processing module and the control module, and configures the XY axis driver and the Z axis driver in the control module;

[0052] S2 provides a workpiece on the workpiece carrier. The control module sends a focus command to the Z-axis driver and the focus module in turn. The Z-axis linear module feeds back the actual height of the focusing lens. The focus module obtains the focal range of the workpiece surface layer. The data processing module parses and generates the focal displacement information. The control module sends a focus command again. The focus lens moves to the position according to the predetermined focal displacement. The Z-axis linear module feeds back the Z-axis coordinate position (Z ij ), the data processing module associates these focused Z-axis coordinate positions with the corresponding XY coordinate positions to construct a morphology distribution map of the workpiece surface layer (X i , Y j , Z ij );

[0053] S3 provides a workpiece on the workpiece carrier, and the control module sends resistivity detection instructions to the XY axis driver, or the XY axis driver and the Z axis driver in turn. The workpiece carrier moves to the position according to the predetermined resistivity detection scanning path, and the resistivity probe selectively moves to the position according to the morphology distribution map obtained in S2. The detection point of the resistivity probe obtains the resistivity ρ of different detection areas on the surface layer of the workpiece. k , the data processing module converts the resistivity ρ of different detection areas into k Compared with the resistivity threshold, if the resistivity ρ k Exceeding the resistivity threshold, and then preliminarily screening out resistivity abnormal areas;

[0054] The S4 control module sends detection instructions to the XY axis driver and the first laser generating module in turn. The workpiece carrier moves to the position according to the predetermined Raman detection scanning path, and the first laser beam passing through the focusing objective lens is focused on the surface layer of the workpiece. The Raman detection module obtains the Raman characteristic peak frequency ω at different focus points on the surface layer of the workpiece. i The image acquisition module obtains the detection image of the workpiece, and the XY axis linear module feedbacks the XY coordinate position of the focus point (X i , Y j );

[0055] S5 combines the detection data of S3 and S4. The data processing module is based on the preset n-ρ inverse proportional function model of the doping concentration n and the resistivity ρ (ρ = 437.7 / n, R = 99%), and the Δω-n linear model of the Raman frequency shift Δω and the doping concentration n (n = 1.27×10 17 Δω, R=99%), determine the doping concentration n ij , and these doping concentrations n ij , the detection image, and the corresponding XY coordinate position to construct the doping concentration distribution map of the workpiece surface layer (X i , Y j , n ij );

[0056] The S6 data processing module determines the laser processing power P at different focus points on the workpiece surface layer based on the doping concentration distribution map and the nP curve model between the preset doping concentration n and the laser processing power P. ij , and these laser processing powers P ij , the detection image, and the corresponding XY coordinate position to construct the power distribution map of the workpiece modified layer (X i , Y j , P ij ); Among them, the fitting function of the nP curve model is P=0.57e [n / (1.18×10^18)] (R=99%);

[0057] The S7 control module sends processing instructions to the XY axis driver, Z axis driver and the second laser generation module (X i , Y j , n ij , P ij ), controls the focal point coordinate position, feed speed, feed direction and laser processing power, the workpiece carrier moves into position according to the predetermined laser processing scanning path, and the focusing objective lens moves into position according to the predetermined focal area displacement (obtained through the topography distribution map), so that the second laser beam passing through the focusing objective lens is focused on the predetermined depth d of the workpiece for internal modification, so as to complete the movement of the focal point approximately along the XY projection plane and perform laser modification on different areas of the modified layer of the workpiece.

[0058] In summary, the beneficial technical effects of the present invention are:

[0059] 1. The present invention integrates processing structures such as the workpiece carrier, focusing lens, moving unit, and laser processing unit, as well as detection structures such as the Raman information acquisition unit and focus height acquisition unit, into a single optical system. This avoids the need for back-and-forth transport of the ingot between detection and processing, thereby saving equipment space, reducing costs, and improving production efficiency.

[0060] 2. The Raman information acquisition unit of the present invention uses a low-power laser with photon energy far below the bandgap energy of silicon carbide to generate Raman signals. A relationship model is established between doping concentration (carrier concentration) and the frequency shift of the Raman characteristic peak (Raman frequency shift). By detecting the Raman frequency shift, the doping concentration of the ingot can be determined, avoiding interference with the Raman characteristic peak from laser scattered light and fluorescence signals, achieving non-destructive and accurate measurement.

[0061] 3. The Raman information acquisition unit of the present invention uses a filter set to cut off the laser light, highly transmit the Raman spectrum band that carries doping concentration information, and improve the signal-to-noise ratio. A convex lens is used to focus the Raman signal. The final Raman characteristic peak frequency is obtained, and the processing laser parameters can be synchronously optimized according to the doping concentration at the ingot detection point. This avoids the inconsistency in the depth and completion of the ingot modified layer caused by uneven doping concentration, improves the wafer peeling quality, and reduces material loss.

[0062] 4. The focus height acquisition unit of the present invention emits reference light to the upper surface of the workpiece and uses the returned reference light to control the Z-axis feed, so that the final focus point is located on the workpiece surface layer. This effectively limits the depth of the Raman signal to the ingot surface, improves the signal-to-noise ratio of the Raman characteristic peak, and can more accurately obtain spatial information of the workpiece surface layer, thereby improving detection accuracy.

[0063] 5. The present invention also utilizes the three-dimensional coordinate position of the detection point to construct the morphological information of the ingot surface, thereby adjusting the processing depth in real time according to the morphological fluctuations of the ingot surface layer during the laser processing process, that is, the Z-axis coordinate position of the focusing objective lens of the processing laser beam, so that the workpiece and the focusing point move relative to each other approximately in the XY direction, and finally achieve the consistency of the processing depth of the modified layer of the ingot. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic structural diagram of the laser processing device of Example 1 of the present invention.

[0065] Figure 2 Schematic diagram of the connection relationship between the workpiece carrier, focusing objective lens, moving unit and control unit in embodiment 2 of the present invention.

[0066] Figure 3 Schematic diagram of the connection relationship between the workpiece carrier, focusing objective lens, XY axis driver, XY axis linear module, Raman information acquisition unit and control unit of embodiment 4 of the present invention.

[0067] Figure 4 It is a schematic diagram of the connection relationship between the workpiece carrier, focusing objective lens, Z-axis driver, Z-axis linear module, focus height acquisition unit and control unit of Example 5 of the present invention.

[0068] Figure 5It is a schematic diagram of the connection relationship between the workpiece carrier, focusing objective lens, moving unit, laser processing unit and control unit of Example 6 of the present invention.

[0069] Figure 6 It is a schematic structural diagram of the laser processing device of Example 9 of the present invention.

[0070] In the figure, 1. workpiece carrier; 2. focusing objective lens; 3. moving unit; 31. XY axis linear module; 32. XY axis driver; 33. Z axis linear module; 34. Z axis driver; 4. Raman information acquisition unit; 41. first laser generating module; 42. Raman detection module; 43. image acquisition module; 44. first dichroic mirror; 45. second dichroic mirror; 46. reflecting mirror; 47. filter group; 48. convex lens; 5. focus height acquisition unit; 51. focus search module; 52. third dichroic mirror; 6. laser processing unit; 61. second laser generating module; 62. laser power monitoring module; 63. fourth dichroic mirror; 64. fifth dichroic mirror; 7. control unit; 71. data processing module; 72. control module; 8. resistivity probe. DETAILED DESCRIPTION

[0071] In order to make the technical means, creative features, objectives and functions achieved by the present invention clearer and easier to understand, the present invention is further explained below with reference to the accompanying drawings and specific implementation methods.

[0072] Example 1: Reference Figure 1 , a laser processing device for SiC crystal ingot disclosed in the present invention, includes a workpiece carrier 1, a focusing objective lens 2, a moving unit 3, a Raman information acquisition unit 4, a focus height acquisition unit 5, a laser processing unit 6, and a control unit 7. The workpiece carrier 1 and the focusing objective lens 2 are respectively arranged at the moving end of the moving unit 3. The moving path of the focusing objective lens 2 passes through the projection light path of the Raman information acquisition unit 4, the focus height acquisition unit 5 and the laser processing unit 6. The moving unit 3, the Raman information acquisition unit 4, the focus height acquisition unit 5 and the laser processing unit 6 respectively establish communication connections with the control unit 7 to complete the focusing of the projection light passing through the focusing objective lens 2 on the workpiece surface layer and the modified layer on the workpiece carrier 1.

[0073] Example 2: Reference Figure 2, a laser processing device for SiC ingots disclosed in the present invention, differs from Example 1 in that the mobile unit 3 includes an XY-axis driver 32, an XY-axis linear module 31, a Z-axis driver 34, and a Z-axis linear module 33. The control unit 7, the XY-axis driver 32, and the XY-axis linear module 31 are sequentially connected in communication, the workpiece carrier 1 is disposed at the mobile end of the XY-axis linear module 31, the control unit 7, the Z-axis driver 34, and the Z-axis linear module 33 are sequentially connected in communication, and the focusing objective lens 2 is disposed at the mobile end of the Z-axis linear module 33.

[0074] The XY axis linear module 31 and the Z axis linear module 33 respectively adopt linear motor type linear modules. The linear motor is the core component of the mobile unit 3, which can convert electrical energy into mechanical energy to generate power and linear motion. Its working principle can be briefly summarized as follows: the user inputs instructions to the control unit 7 through the human-machine interface or other input devices, such as setting the motor's feed speed, direction and other parameters; the control unit 7 receives the input signal and calculates it according to the preset algorithm, control strategy and feedback signal to generate a control signal; the control module 72 of the control unit 7 reads the feedback signal of the motor, which is usually obtained through a sensor, such as using an encoder to feedback the motor's feed speed and position information; the controller sends the calculated control signal to the driver; the driver receives the control signal and generates a control signal. The control signal is converted into voltage or current according to the characteristics of the signal, and a voltage or current signal suitable for the motor operation of the linear module is output; the driving signal flows through the motor winding, generates an electromagnetic field, drives the motor to rotate, the voltage signal controls the speed and direction of the DC motor, and the current signal controls the frequency and phase of the AC motor; the controller continuously monitors the status and environmental conditions of the motor, such as current, temperature, etc., and compares them with the preset protection parameters. If the set range is exceeded, the protection device is triggered to prevent the motor from being damaged by overload, overheating, short circuit, etc.; by continuously looping the above steps, the control unit 7 can stably control the feed speed, direction and position information of the linear module through the driver, realize the user's expected action, and obtain the coordinate position of the moving part.

[0075] Example 3: Reference Figure 1 , is a laser processing device for SiC crystal ingot disclosed in the present invention. The difference from Example 2 is that the projection end of the Raman information acquisition unit 4, the projection end of the focus height acquisition unit 5, the projection end of the laser processing unit 6, and the focusing objective lens 2 are arranged sequentially along the moving direction of the Z-axis linear module 33.

[0076] Example 4: Reference Figure 3, a SiC ingot laser processing device disclosed in the present invention, differs from Example 3 in that the Raman information acquisition unit 4 includes a first laser generating module 41, a Raman detection module 42, an image acquisition module 43, and a detection optical path module. The light output end of the first laser generating module 41 faces the light input end of the detection optical path module, while the detection ends of the Raman detection module 42 and the image acquisition module 43 face the light output end of the detection optical path module. The projection light path of the detection optical path module passes through the focusing objective lens 2.

[0077] Specifically, the first laser generating module 41 is configured as a continuous laser; the Raman detection module 42 is configured as a high-resolution Raman spectrometer; the image acquisition module 43 is configured as a CCD camera with an illumination light source; the detection optical path module includes a first dichroic mirror 44, a second dichroic mirror 45, a reflector 46, a filter group 47, and a convex lens 48. The first dichroic mirror 44 is arranged between the focusing objective lens 2 and the image acquisition module 43, the second dichroic mirror 45 is arranged between the first laser generating module 41 and the first dichroic mirror 44, the reflector 46, the filter group 47, the convex lens 48 and the Raman detection module 42 are arranged in sequence on the beam splitting path on the side of the second dichroic mirror 45 away from the first laser generating module 41.

[0078] During the facet detection process, the detection optical path module forms two projection optical paths that pass through the focusing objective lens 2. In one of the projection optical paths, after the first laser generating module 41 emits a first laser beam, it is first transmitted by the second dichroic mirror 45, reflected by the first dichroic mirror 44, and then focused on the workpiece surface layer by the focusing objective lens 2 to form a detection point. The fluorescence on the workpiece surface returns to the focusing objective lens 2, is then reflected by the first dichroic mirror 44, the second dichroic mirror 45, and the reflector 46. The filter group 47 cuts off the laser, and the convex lens 48 focuses the Raman signal. Then, the Raman detection module 42 forms a Raman spectrum and obtains the final Raman characteristic peak frequency.

[0079] At the same time, another projection light route emits illumination light from the image acquisition module 43, which is first transmitted by the first dichroic mirror 44, and then focused on the surface layer of the workpiece through the focusing objective lens 2 to form an illumination area. The image of the workpiece surface returns to the focusing objective lens 2, and then is transmitted by the first dichroic mirror 44. The image information is then collected by the image acquisition module 43 to obtain the final detection image.

[0080] Example 5: Reference Figure 4 , a SiC ingot laser processing device disclosed in the present invention, differs from Example 4 in that the focus height acquisition unit 5 includes a focus finding module 51 and a focusing optical path module. The light emitting end and detection end of the focus finding module 51 are respectively directed toward the focusing optical path module, and the projection light path of the focusing optical path module passes through the focusing objective lens 2.

[0081] Specifically, the focus-finding module 51 is configured as a line laser focus sensor; the focusing optical path module includes a third dichroic mirror 52, which is arranged between the focusing objective lens 2 and the first dichroic mirror 44, and the focusing optical path module is arranged on the beam splitting path on the side of the third dichroic mirror 52 away from the first dichroic mirror 44.

[0082] During the focusing process, a line laser is first emitted by the focusing module 51, which is reflected by the third dichroic mirror 52 and then focused on the top of the workpiece through the focusing objective lens 2. The light spot on the surface of the workpiece returns to the focusing objective lens 2, and then is reflected by the third dichroic mirror 52. The focal range is then collected by the focusing module 51.

[0083] Example 6: Reference Figure 5 , a laser processing device for SiC ingots disclosed in the present invention, differs from Example 5 in that the laser processing unit 6 includes a second laser generating module 61, a laser power monitoring module 62, and a processing optical path module. The light output end of the second laser generating module 61 faces the light input end of the processing optical path module, and the light input ends of the laser power monitoring module 62 and the focusing objective lens 2 face the light output end of the processing optical path module.

[0084] Specifically, the second laser generating module 61 is configured as a pulsed laser; the laser power monitoring module 62 is configured as a high-precision optical power meter; the processing optical path module includes a fourth dichroic mirror 63 and a fifth dichroic mirror 64, the fourth dichroic mirror 63 is arranged between the focusing objective lens 2 and the third dichroic mirror 52, the fifth dichroic mirror 64 is arranged between the second laser generating module 61 and the fourth dichroic mirror 63, and the laser power monitoring module 62 is arranged on the beam splitting path on the side of the fifth dichroic mirror 64 away from the fourth dichroic mirror 63.

[0085] During the laser modification process, the second laser beam emitted by the pulsed laser is divided into a third laser beam and a fourth laser beam by the fifth dichroic mirror 64 at a ratio of 99:1. After the third laser beam is reflected by the fourth dichroic mirror 63, it is focused at a predetermined depth on the back of the workpiece through the focusing objective lens 2 to form a modified point. At the same time, the laser power monitoring module 62 receives the fourth laser beam and monitors and feeds back the energy of the processing laser in real time.

[0086] Example 7: Reference Figure 1 , is a SiC ingot laser processing device disclosed in the present invention, which differs from Example 6 in that the control unit 7 includes a data processing module 71 and a control module 72, and the data processing module 71 and the control module 72 are communicatively connected;

[0087] The XY-axis driver 32, the first laser generating module 41, the Raman detection module 42, and the image acquisition module 43 respectively establish communication connections with the control module 72. The data processing module 71 associates the Raman characteristic peak frequency, image information, and corresponding XY coordinate position of the focus point to complete the construction of the doping concentration distribution map of the workpiece surface layer and the power distribution map of the workpiece modified layer.

[0088] The Z-axis driver 34 and the focus search module 51 respectively establish communication connections with the control module 72, and the data processing module 71 associates the Z-axis coordinate position of the focusing lens 2 with the corresponding XY coordinate position of the focus point to complete the construction of the topography distribution map of the workpiece surface layer;

[0089] The XY-axis driver 32, the Z-axis driver 34, the second laser generating module 61 and the laser power monitoring module 62 respectively establish communication connections with the control module 72, so that the workpiece and the focal point on the workpiece carrier 1 move relative to each other approximately in the XY direction and form a modified layer on the workpiece.

[0090] Example 8: Reference Figures 2 to 5 , is a SiC ingot laser processing device disclosed in the present invention, which is different from Example 7 in that the control process of the laser processing device is:

[0091] S1 establishes a communication connection between the data processing module 71 and the control module 72, and configures the XY axis driver 32 and the Z axis driver 34 in the control module 72;

[0092] S2 provides a workpiece on the workpiece carrier 1, and the control module 72 sends detection instructions to the XY axis driver 32 and the first laser generating module 41 in turn. The workpiece carrier 1 moves to the position according to the predetermined Raman detection scanning path, and the first laser beam passing through the focusing lens 2 is focused on the surface layer of the workpiece. The Raman detection module 42 obtains the Raman characteristic peak frequency ωi at different focus points on the surface layer of the workpiece, and the image acquisition module 43 obtains the detection image of the workpiece. The XY axis linear module 31 feedbacks the XY coordinate position (X i , Y j ), the data processing module 71 determines the doping concentration n based on the Δω-n linear model ij , and these doping concentrations n ij , the detection image, and the corresponding XY coordinate position to construct the doping concentration distribution map of the workpiece surface layer (X i , Y j , n ij );

[0093] Among them, the fitting function of the Δω-n linear model is n=1.27×10 17Δω (R=99%), specifically implemented by providing a plurality of silicon carbide standards with different doping concentrations n on the workpiece carrier 1, the Raman detection module 42 obtaining the Raman characteristic peak frequencies ωn of these standards, the data processing module 71 performing difference calculation based on the Raman characteristic peak frequency ωn of one of the standards, and determining the relative Raman frequency shift Δω, and then establishing a Δω-n linear model of the relative Raman frequency shift Δω and the doping concentration n based on the least squares method;

[0094] The data processing module 71 determines the laser processing power P at different focus points on the surface layer of the workpiece based on the doping concentration distribution diagram and the nP curve model between the preset doping concentration n and the laser processing power P. ij , and these laser processing powers P ij , the detection image, and the corresponding XY coordinate position to construct the power distribution map of the workpiece modified layer (X i , Y j , P ij ); Among them, the fitting function of the nP curve model is P=0.57e [n / (1.18×10^18)] (R=99%);

[0095] At the same time, the control module 72 sends a focus command to the Z-axis driver 34 and the focus module 51 in turn. The Z-axis linear module 33 feeds back the actual height of the focusing lens 2. The focus module 51 obtains the focal range of the workpiece surface layer. The data processing module 71 parses and generates focal displacement information. The control module 72 sends a focus command again. The focus lens moves to the position according to the predetermined focal displacement. The Z-axis linear module 33 feeds back the Z-axis coordinate position (Z ij ), the data processing module 71 associates these focused Z-axis coordinate positions with the corresponding XY coordinate positions to construct a morphology distribution map of the workpiece surface layer (X i , Y j , Z ij );

[0096] S3 The control module 72 issues a processing instruction to the XY axis driver 32, the Z axis driver 34 and the second laser generating module 61 (X i , Y j , n ij , P ij ), controls the focal point coordinate position, feed speed, feed direction and laser processing power, the workpiece carrier 1 moves into position according to the predetermined laser processing scanning path, and the focusing objective lens 2 moves into position according to the predetermined focal range displacement, so that the second laser beam passing through the focusing objective lens 2 is focused on the predetermined depth d of the workpiece for internal modification, so as to complete the movement of the focal point approximately along the XY projection plane and perform laser modification on different areas of the modified layer of the workpiece.

[0097] Example 9: Reference Figure 6 , is a laser processing device for SiC crystal ingots disclosed in the present invention. The difference from Example 7 is that it also includes a resistivity probe 8. The resistivity probe 8 is installed on the moving end of the moving unit 3 in such a way that the detection point faces the workpiece carrier 1, and the resistivity probe 8 establishes a communication connection with the control unit 7 to complete the resistivity detection of the surface layer of the workpiece on the workpiece carrier 1.

[0098] If the resistivity probe 8 is a contact-type resistivity probe 8 with a detection range of 0.1 to 100 mΩ·cm and a measurement accuracy of ≤0.5 mΩ·cm, the resistivity probe 8 and focusing objective lens 2 are independently mounted on the movable end of the Z-axis linear module 33 (not shown). Simultaneously, the XY-axis driver 32, the Z-axis driver 34, and the resistivity probe 8 are each communicatively connected to the control module 72, so that the detection end of the resistivity probe 8 contacts the workpiece surface of the workpiece carrier 1 and performs resistivity detection on different areas of the workpiece surface layer.

[0099] If the resistivity probe 8 is a non-contact resistivity probe 8 and the detection range of the resistivity probe 8 is 0.1 to 100 mΩ·cm, the measurement accuracy is ≤ 0.5 mΩ·cm. Simultaneously, the XY-axis driver 32 and the resistivity probe 8 are each connected to the control module 72 so that the detection end of the resistivity probe 8 passes over the outside of the workpiece on the workpiece carrier 1 and performs resistivity detection on different areas of the workpiece surface layer.

[0100] Specifically, if the resistivity probe 8 is a contact resistivity probe 8, the control process of the laser processing device is as follows:

[0101] S1 establishes a communication connection between the data processing module 71 and the control module 72, and configures the XY axis driver 32 and the Z axis driver 34 in the control module 72;

[0102] S2 provides a workpiece on the workpiece carrier 1, and the control module 72 sends a focus command to the Z-axis driver 34 and the focus module 51 in turn. The Z-axis linear module 33 feeds back the actual height of the focusing lens 2. The focus module 51 obtains the focal range of the workpiece surface layer. The data processing module 71 parses and generates focal displacement information. The control module 72 sends a focus command again. The focus lens moves to the position according to the predetermined focal displacement. The Z-axis linear module 33 feeds back the Z-axis coordinate position (Z ij ), the data processing module 71 associates these focused Z-axis coordinate positions with the corresponding XY coordinate positions to construct a morphology distribution map of the workpiece surface layer (X i , Y j , Z ij );

[0103] S3 provides a workpiece on the workpiece carrier 1, and the control module 72 sequentially initiates resistivity detection instructions to the XY axis driver 32, or the XY axis driver 32 and the Z axis driver 34. The workpiece carrier 1 moves to a position according to the predetermined resistivity detection scanning path, and the resistivity probe 8 selectively moves to a position according to the morphology distribution map obtained in S2. The detection point of the resistivity probe 8 obtains the resistivity ρ of different detection areas on the surface layer of the workpiece. k The data processing module 71 converts the resistivity ρ of different detection areas into k Compared with the resistivity threshold, if the resistivity ρ k Exceeding the resistivity threshold, and then preliminarily screening out resistivity abnormal areas;

[0104] S4 control module 72 sends detection instructions to XY axis driver 32 and first laser generating module 41 in turn. Workpiece carrier 1 moves to the position according to the predetermined Raman detection scanning path, and the first laser beam passing through focusing lens 2 is focused on the surface layer of the workpiece. Raman detection module 42 obtains Raman characteristic peak frequency ω at different focus points on the surface layer of the workpiece. i The image acquisition module 43 obtains the detection image of the workpiece, and the XY axis linear module 31 feedbacks the XY coordinate position of the focus point (X i , Y j );

[0105] S5 combines the detection data of S3 and S4, and the data processing module 71 uses the preset n-ρ inverse proportional function model of the doping concentration n and the resistivity ρ (ρ = 437.7 / n, R = 99%) and the Δω-n linear model of the Raman frequency shift Δω and the doping concentration n (n = 1.27×10 17 Δω, R=99%), determine the doping concentration n ij , and these doping concentrations n ij , the detection image, and the corresponding XY coordinate position to construct the doping concentration distribution map of the workpiece surface layer (X i , Y j , n ij );

[0106] S6 data processing module 71 determines the laser processing power P at different focus points on the workpiece surface layer based on the doping concentration distribution diagram and the nP curve model between the preset doping concentration n and the laser processing power P. ij , and these laser processing powers P ij , the detection image, and the corresponding XY coordinate position to construct the power distribution map of the workpiece modified layer (X i , Y j , P ij ); Among them, the fitting function of the nP curve model is P=0.57e [n / (1.18×10^18)] (R=99%);

[0107] S7 control module 72 sends processing instructions to XY axis driver 32, Z axis driver 34 and second laser generating module 61 (X i , Y j , n ij , P ij ), controls the focal point coordinate position, feed speed, feed direction and laser processing power, the workpiece carrier 1 moves into position according to a predetermined laser processing scanning path, and the focusing objective lens 2 moves into position according to a predetermined focal area displacement (obtained through a topography distribution diagram), so that the second laser beam passing through the focusing objective lens 2 is focused on a predetermined depth d of the workpiece for internal modification, thereby completing the movement of the focal point approximately along the XY projection plane and performing laser modification on different areas of the modified layer of the workpiece.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A laser processing device for SiC ingots, characterized in that: The invention comprises a workpiece carrier (1), a focusing lens (2), a moving unit (3), a Raman information acquisition unit (4), a focus height acquisition unit (5), a laser processing unit (6), and a control unit (7); the workpiece carrier (1) and the focusing lens (2) are respectively arranged at the moving end of the moving unit (3); the moving path of the focusing lens (2) passes through the projection light path of the Raman information acquisition unit (4), the focus height acquisition unit (5), and the laser processing unit (6); the moving unit (3), the Raman information acquisition unit (4), the focus height acquisition unit (5), and the laser processing unit (6) respectively establish communication connections with the control unit (7) to complete the focusing of the projection light passing through the focusing lens (2) on the workpiece surface layer and the modified layer on the workpiece carrier (1); The mobile unit (3) includes an XY-axis driver (32), an XY-axis linear module (31), a Z-axis driver (34) and a Z-axis linear module (33); the control unit (7), the XY-axis driver (32) and the XY-axis linear module (31) are sequentially connected to establish a communication connection; the workpiece carrier (1) is arranged at the mobile end of the XY-axis linear module (31); the control unit (7), the Z-axis driver (34) and the Z-axis linear module (33) are sequentially connected to establish a communication connection; and the focusing lens (2) is arranged at the mobile end of the Z-axis linear module (33); The Raman information acquisition unit (4) comprises a first laser generating module (41), a Raman detection module (42), and a detection light path module, wherein the light output end of the first laser generating module (41) faces the light input end of the detection light path module, the detection end of the Raman detection module (42) faces the light output end of the detection light path module, and the projection light path of the detection light path module passes through the focusing objective lens (2); The Raman information acquisition unit (4) further includes an image acquisition module (43), wherein the detection end of the image acquisition module (43) faces the light output end of the detection light path module; The control unit (7) includes a data processing module (71) and a control module (72), and the data processing module (71) and the control module (72) are communicatively connected; The XY axis driver (32), the first laser generating module (41), the Raman detection module (42) and the image acquisition module (43) respectively establish communication connections with the control module (72), and the data processing module (71) associates the Raman characteristic peak frequency, image information and corresponding XY coordinate position of the focus point to complete the construction of the doping concentration distribution map of the workpiece surface layer and the power distribution map of the workpiece modified layer in sequence; wherein, the data processing module (71) determines the laser processing power P of different focus points on the workpiece surface layer based on the doping concentration distribution map and the nP curve model between the preset doping concentration n and the laser processing power P ij , and these laser processing powers P ij , the detection image, and the corresponding XY coordinate position to construct the power distribution map of the workpiece modified layer (X i , Y j , P ij ); The Z-axis driver (34) and the focus search module (51) are respectively connected to the control module (72), and the data processing module (71) associates the Z-axis coordinate position of the focusing lens (2) and the corresponding XY coordinate position of the focus point to complete the construction of the morphology distribution map of the workpiece surface layer; The XY axis driver (32), the Z axis driver (34), the second laser generating module (61) and the laser power monitoring module (62) are respectively connected to the control module (72) so that the workpiece and the focus on the workpiece carrier (1) are relatively moved approximately in the XY direction and a modified layer is formed on the workpiece; wherein the control module (72) initiates a processing instruction (XY axis driver (32), the Z axis driver (34) and the second laser generating module (61) i , Y j , n ij , P ij ), controlling the focus point coordinate position, feed speed, feed direction and laser processing power, the workpiece carrier (1) moves to a position according to a predetermined laser processing scanning path, and the focusing lens (2) moves to a position according to a predetermined focal range displacement, so that the second laser beam passing through the focusing lens (2) is focused on a predetermined depth d of the workpiece to perform internal modification, thereby completing the movement of the focus point approximately along the XY projection plane and performing laser modification on different areas of the modified layer of the workpiece.

2. The laser processing device for SiC ingot according to claim 1, characterized in that: The projection end of the Raman information acquisition unit (4), the projection end of the focus height acquisition unit (5), the projection end of the laser processing unit (6), and the focusing objective lens (2) are sequentially arranged along the moving direction of the Z-axis linear module (33).

3. The laser processing device for SiC ingot according to claim 2, characterized in that: The focus height acquisition unit (5) comprises a focus search module (51) and a focus light path module, wherein the light output end and the detection end of the focus search module (51) are respectively directed toward the focus light path module, and the projection light path of the focus light path module passes through the focus objective lens (2).

4. The laser processing device for SiC ingot according to claim 3, characterized in that: The laser processing unit (6) comprises a second laser generating module (61) and a processing light path module, wherein the light output end of the second laser generating module (61) faces the light input end of the processing light path module, and the light input end of the focusing objective lens (2) faces the light output end of the processing light path module.

5. The laser processing device for SiC ingot according to claim 4, characterized in that: The laser processing unit (6) further comprises a laser power monitoring module (62), wherein the light input end of the laser power monitoring module (62) faces the light output end of the processing optical path module.

6. The laser processing device for SiC ingot according to claim 1, characterized in that: The invention also includes a resistivity probe (8), which is installed at the moving end of the moving unit (3) in a manner such that the detection point faces the workpiece carrier (1), and the resistivity probe (8) establishes a communication connection with the control unit (7) to complete the resistivity detection of the workpiece surface layer on the workpiece carrier (1).

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