Laser modification method and device for semiconductor crystal ingot

Abstract

The invention provides a laser modification method and device for a semiconductor crystal ingot. The laser modification method comprises the following steps: determining a facet area of the semiconductor crystal ingot; carrying out laser modification treatment on the material layer, at the preset depth position, of the semiconductor crystal ingot, wherein the laser modification treatment comprises the steps of treating the material layer in a small-surface region based on a first laser parameter and treating the material layer in a non-small-surface region based on a second laser parameter; the modification irradiation energy corresponding to the first laser parameter is greater than the modification irradiation energy corresponding to the second laser parameter. A regional differentiated modification mode is adopted, laser irradiation energy is enhanced according to material characteristics of a facet region to realize accurate modification, so that laser scanning times equal to that of a non-facet region are adopted in the facet region, namely, complete modification of a whole processing plane at a preset depth position of a semiconductor crystal ingot can be completed; therefore, the laser modification efficiency of the semiconductor crystal ingot is improved, and the utilization rate of a semiconductor material is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor cutting technology, and in particular to a laser modification method and apparatus for semiconductor ingots. Background Technology

[0002] Third-generation semiconductor materials, represented by silicon carbide (SiC), gallium arsenide (GaAs), and gallium nitride (GaN), have complex ingot growth processes and high material hardness, increasing the difficulty of semiconductor wafer processing. To improve the cutting efficiency and reduce the cutting cost of such semiconductor ingots, laser stealth cutting technology is currently the main cutting technology of interest. Its core principle is to use a high-energy-density pulsed laser (including ultra-short timescales and extremely high energy concentrations) to focus at a certain depth inside the semiconductor ingot to generate a modified layer containing transverse microcracks or dislocation networks at that depth. Then, thermochemical, physical-mechanical, or ultrasonic methods are used to separate the semiconductor wafer above the modified layer from the semiconductor ingot below the modified layer.

[0003] In existing technologies, semiconductor ingots are scanned using the same laser parameters across the entire area. Semiconductor ingots typically contain small facet regions, which are specific areas on the crystal surface or at the interface. These regions possess physical and chemical properties different from the rest of the ingot. For example, taking silicon carbide (SiC) ingots as an example, SiC ingots typically have small facet regions that penetrate axially throughout the interior of the ingot (see reference). Figure 1 As shown in the figure, this is an inherent phenomenon caused by factors such as crystal structure, crystallization direction, and doping, which is difficult to overcome with existing semiconductor ingot growth technology. During research and development, the following technical problems were found: the material physical properties of the facet region are unique, such as high resistivity, high refractive index, and the highest thermal stress in the entire region. Using the same laser parameters for scanning the entire region often fails to effectively modify the facet region, thus affecting the smooth progress of subsequent physical wafer peeling, reducing peeling yield, and in some cases, damaging the material in other regions. However, using the same laser parameters for scanning the entire semiconductor ingot requires repeated laser modification of the facet region, resulting in low laser modification efficiency for the semiconductor ingot.

[0004] It should be noted that the above description of the background technology is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background technology section of this application. Summary of the Invention

[0005] The purpose of this application is to provide a laser modification method and apparatus for semiconductor ingots, so as to improve the laser modification efficiency of semiconductor ingots and at the same time improve the utilization rate of semiconductor materials.

[0006] To achieve the above object, the embodiment of the present application provides a laser modification method of a semiconductor crystal ingot, comprising:

[0007] Determining a facet region of the semiconductor crystal ingot;

[0008] Performing laser modification processing on a material layer at a preset depth position of the semiconductor crystal ingot, comprising: processing the material layer in the facet region based on a first laser parameter, and processing the material layer in a non-facet region based on a second laser parameter; the modification irradiation energy corresponding to the first laser parameter is greater than the modification irradiation energy corresponding to the second laser parameter.

[0009] As a further improvement of the present application, the laser modification processing on the material layer at the preset depth position of the semiconductor crystal ingot comprises:

[0010] Based on a spatial light modulator, the original laser beam emitted by the laser is beam shaped to generate a plurality of focal point different sub-beams; wherein the spatial modulator splits the original laser beam into a plurality of sub-beams with different wave fronts by modulating the phase of the original laser beam;

[0011] Based on a plurality of the sub-beams, the laser modification processing is performed on the material layer at the preset depth position of the semiconductor crystal ingot to obtain a modified layer.

[0012] As a further improvement of the present application, the first laser parameter is modulated based on the facet region to obtain a plurality of first sub-beams; the first laser parameter comprises: the arrangement density of the first sub-beams, and the first power corresponding to a single first sub-beam;

[0013] The second laser parameter is modulated based on the non-facet region to obtain a plurality of second sub-beams; the second laser parameter comprises: the arrangement density of the second sub-beams, and the second power corresponding to a single second sub-beam;

[0014] Wherein, the arrangement density of the first sub-beams is greater than the arrangement density of the second sub-beams, and the first power is greater than the second power.

[0015] As a further improvement of the present application, the determination of the facet region of the semiconductor crystal ingot comprises:

[0016] An imaging system is configured with a laser detection device to detect the semiconductor crystal ingot to obtain an imaging result; according to the difference of the imaging result, the boundary of the original facet region of the semiconductor crystal ingot is identified; according to the maximum value data of the length and width of the boundary, a rectangular region is constructed, and the rectangular region is determined as a facet region; or,

[0017] Obtaining a recognition result of a facet region from a laser detection device configured with an imaging system.

[0018] As a further improvement of the present application, the above method further comprises:

[0019] A first laser parameter is set for a facet region of a semiconductor ingot, and a second laser parameter is set for a non-facet region.

[0020] As a further improvement of the present application, the laser modification processing of the material layer at the preset depth position of the semiconductor ingot comprises:

[0021] The semiconductor ingot is subjected to full-area laser scanning, and the original laser beam is subjected to beam splitting and shaping processing according to the type of the laser scanning region and matching the first laser parameter or the second laser parameter, wherein when the laser scanning region is the facet region, the original laser beam is shaped into a plurality of first sub-beams according to the first laser parameter; and when the laser scanning region is the non-facet region, the original laser beam is shaped into a plurality of second sub-beams according to the second laser parameter.

[0022] The focal points of the first sub-beams are focused on the material layer in the facet region at the preset depth position of the semiconductor ingot, and the focal points of the second sub-beams are focused on the material layer in the non-facet region at the preset depth position of the semiconductor ingot, to form a modified layer.

[0023] As a further improvement of the present application, during the laser modification processing, the same number of laser scanning times is adopted in the facet region and the non-facet region, and the modified layer is formed on the entire processing plane at the preset depth position of the semiconductor ingot.

[0024] As a further improvement of the present application, the scanning path of the laser scanning is configured to be oriented and relatively moved at a controllable distance along at least one of a first coordinate direction and a second coordinate direction, wherein the plane in which the first coordinate direction and the second coordinate direction are located is perpendicular to the depth direction.

[0025] The movement mechanism of the laser scanning comprises moving a carrier table and / or adjusting a laser light path, wherein the step distance of the laser scanning and the interval between the focal points of the beam-splitting and shaping sub-beams are matched.

[0026] As a further improvement of the present application, the above method further comprises at least one of the following:

[0027] The interval between the first sub-beams is 80 μm to 120 μm, and the first power is 14 w to 16 w; the interval between the second sub-beams is 180 μm to 220 μm, and the power of a single beam is 11 w to 13 w; or,

[0028] The original laser beam adopts a pulsed laser with a wavelength ranging from 532 nm to 1064 nm, a pulse frequency of 100 kHz to 2000 kHz, a power of 20 w to 80 w, and a pulse width including picosecond and femtosecond, wherein the pulse width of the picosecond ranges from 10 picoseconds to 300 picoseconds, and the pulse width of the femtosecond ranges from 500 femtoseconds to 800 femtoseconds; or

[0029] The surface of the semiconductor crystal ingot is subjected to surface smoothing treatment, so that the surface roughness of the surface corresponding to the laser incidence direction of the semiconductor crystal ingot is less than or equal to 10 nm; or

[0030] The modified semiconductor crystal ingot is immersed in a liquid medium and subjected to ultrasonic vibration, so that the semiconductor crystal ingot is separated based on the modification layer, and a separated semiconductor wafer is obtained; a wafer with a diameter of 2 inches to 12 inches is formed based on the semiconductor wafer, or a semiconductor seed crystal or a semiconductor substrate is formed based on the semiconductor wafer.

[0031] As a further improvement of the present application, a laser modification optical path system is constructed to perform laser modification treatment on the material layer of the semiconductor crystal ingot at a preset depth position, and the laser modification optical path system is constructed as follows:

[0032] The original laser beam emitted by the laser is expanded by the beam expander, and then is split and modulated by the spatial light modulator and the 4f system, and then the plurality of modulated sub-beams are guided by the mirror group and focused by the focusing lens, and then are irradiated on the incident surface of the semiconductor crystal ingot.

[0033] The original laser beam emitted by the laser is expanded by the beam expander, and then is split and modulated by the spatial light modulator and the 4f system, and then the plurality of modulated sub-beams are guided by the mirror group and focused by the focusing lens, and then are irradiated on the incident surface of the semiconductor crystal ingot.

[0034] To achieve the above object, the embodiments of the present application simultaneously provide a laser modification device for a semiconductor crystal ingot, which comprises:

[0035] The region determination module is used to determine the facet region of the semiconductor crystal ingot.

[0036] The laser modification optical path system is used to perform laser modification treatment on the material layer of the semiconductor crystal ingot at a preset depth position, and comprises: treating the material layer in the facet region based on a first laser parameter, and treating the material layer in the non-facet region based on a second laser parameter; the modification irradiation energy corresponding to the first laser parameter is greater than the modification irradiation energy corresponding to the second laser parameter.

[0037] As a further improvement of the present application, it further comprises:

[0038] A spatial light modulator is configured in the laser modification optical path system, and is used to perform beam shaping on the original laser beam emitted by the laser based on the first laser parameter or the second laser parameter, so as to generate a plurality of focal point different sub-beams;

[0039] A controller is used to receive the input of the area determination module, and to regulate and control the laser modification optical path system to match the processing parameters, wherein the output power of the original laser beam is dynamically adjusted, the first laser parameter and the second laser parameter are dynamically switched, and the step distance of the laser scanning is matched with the first laser parameter and the second laser parameter.

[0040] The plurality of sub-beams irradiate the incident surface of the semiconductor crystal ingot through the laser modification optical path system.

[0041] Compared with the prior art, the beneficial effects of the embodiments of the present application include at least part or all of the following:

[0042] The laser modification method and device for the semiconductor crystal ingot provided by the embodiments of the present application adopt a differential modification method in different areas for the facet area and the non-facet area, enhance the laser irradiation energy according to the material properties of the facet area to achieve accurate modification, so as to realize the same number of laser scanning times in the facet area and the non-facet area, that is, the entire modification of the processing plane at the preset depth position of the semiconductor crystal ingot can be completed, which is convenient for the subsequent whole layer peeling of the semiconductor wafer and the crystal ingot. The modification method can improve the laser modification efficiency of the semiconductor crystal ingot, and at the same time, improve the utilization rate of the semiconductor material. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 A structural schematic diagram of a semiconductor crystal ingot with a facet area is shown;

[0044] Figure 2 A flowchart of a laser modification method for a semiconductor crystal ingot provided by the embodiments of the present application is shown;

[0045] Figure 3 A schematic diagram of a laser detection device provided by the embodiments of the present application and configured with an imaging system is shown;

[0046] Figure 4 A flowchart of self-adaptive optimization and construction of the boundary of the facet area is shown;

[0047] Figure 5 A structural schematic diagram of self-adaptive optimization of the boundary of the facet area based on the semiconductor crystal ingot is shown, wherein (a) is a result schematic diagram of identifying the original facet area in the semiconductor crystal ingot, and (b) is a result schematic diagram of obtaining the facet area based on the original facet area;

[0048] Figure 6A schematic diagram of a laser modification device provided for an embodiment of the present application;

[0049] Figure 7 A flowchart of a laser modification process for a semiconductor ingot provided for an embodiment of the present application;

[0050] Figure 8 A schematic diagram of a cross-sectional structure of a semiconductor ingot during a laser modification process provided for an embodiment of the present application, wherein (a) is a schematic diagram of a first sub-beam irradiating a facet region, and (b) is a schematic diagram of a second sub-beam irradiating a non-facet region;

[0051] Figure 9 A schematic diagram of a scanning path of a laser scanning in an XY plane of a semiconductor ingot provided for an embodiment of the present application;

[0052] Figure 10 A schematic diagram of adjustment of a scanning step distance of a laser scanning provided for an embodiment of the present application.

[0053] Figure 11 A flowchart of a laser modification process for a silicon carbide ingot provided for an embodiment of the present application;

[0054] Figure 12 A local micrograph of a modification layer surface of a silicon carbide wafer obtained based on a modification process flow provided for an embodiment of the present application. Figure 11 BRIEF DESCRIPTION OF DRAWINGS

[0055]

[0056] 10, semiconductor ingot, 10a, original facet region, 10a, facet region, 10b, non-facet region, 101, moving platform, 11, modification layer;

[0057] 20, laser modification device, 210, modification laser, 21, original laser beam, 21a, first sub-beam unit, 211a, first sub-beam, 21b, second sub-beam unit, 221b, second sub-beam, 22, beam expander, 23, spatial light modulator, 24, 4f system, 241, first lens, 242, second lens, 25, mirror group, 251, first mirror, 252, second mirror, 253, third mirror, 254, fourth mirror, 26, focusing mirror, 201, modification station, 220, controller;

[0058] 30, laser detection device, 31, light source assembly, 311, detection laser, 312, polarizer, 313, condenser lens, 32, imaging system, 321, half mirror, 322, objective lens, 323, 1 / 4 wave plate, 324, analyzer, 325, focusing lens, 326, CCD camera, 301, detection station; ​

[0059] d1, first sub-beam spacing, d2, second sub-beam spacing, D1, first step distance, D2, second step distance, L, scanning path, h, depth. DETAILED DESCRIPTION

[0060] The present application will be described in detail below with reference to the embodiments shown in the drawings, but it should be noted that these embodiments are not limiting to the present application, and equivalent transformations or substitutions of function, method, or structure made by those skilled in the art based on these embodiments are within the scope of protection of the present application.

[0061] The technical solution provided by the present application has wide applicability and is suitable for semiconductor ingots that are both brittle and hard and are prone to facet defects during crystal growth, such as silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), etc. In view of the differences in physical properties between the facet region and the normal region (i.e., non-facet region) of such semiconductor ingots and the problem that a single laser cannot completely modify the quality, the present application provides the following laser modification method and device.

[0062] Reference Figure 2 As shown in FIG. 1, the embodiment of the present application provides a laser modification method for a semiconductor ingot, which includes steps S1 and S2.

[0063] Step S1, determining the facet region of the semiconductor ingot.

[0064] In combination with Figure 1 As shown in FIG. 2, due to the difference in crystal orientation between the original facet region 10a0 and the non-facet region 10b (such as the basal plane region) of the semiconductor ingot 10 (e.g., facet {11-20}, non-facet {0001}), the refractive index and phase delay of polarized light are different, and after passing through the orthogonal polarization system, the light and dark contrast difference is generated (the facet appears as a bright area, and the non-facet appears as a dark area), and the position region of the original facet region 10a0 can be identified by capturing this difference through the imaging system.

[0065] A rough surface can cause light scattering or electron beam signal interference, reducing the imaging clarity and contrast. In order to optimize the imaging quality and reduce the reflection of incident laser during the modification process, and improve the utilization efficiency of the output energy of the laser, the surface of the semiconductor ingot 10 is smoothed before the detection imaging of the semiconductor ingot 10, for example, the surface roughness of the surface (i.e., the incident surface) of the semiconductor ingot 10 corresponding to the laser incident direction is less than or equal to 10 nm.

[0066] In some embodiments, as shown in FIG. 3, the laser modification method for the semiconductor ingot includes the following steps. Figure 3The laser detection device 30 shown performs detection and identification. The laser detection device 30 is configured with a light source assembly 31 and an imaging system 32. The semiconductor crystal ingot 10 to be detected and identified is positioned at a detection station 301. The light source assembly 31 emits laser light to the incident surface of the semiconductor crystal ingot 10 (the laser emission light path is shown in solid lines in Figure 3 FIG. 6). The reflected light is then received by the imaging system 32 (the laser reception light path is shown in dashed lines in Figure 3 FIG. 6) and an image is formed. The imaging result is output, for example, as a gray scale image as shown in (a) of Figure 5 FIG. 6.

[0067] For positioning of the semiconductor crystal ingot 10, for example, the semiconductor crystal ingot 10 can be fixed on a porous ceramic base (not shown) by using the adsorption principle of a vacuum porous ceramic disc. The semiconductor crystal ingot 10 is fixed relative to the ceramic base during the entire processing to ensure the accuracy of the modification. The ceramic base can be fixed on the moving platform 101. The relative movement between the light source assembly 21 and the semiconductor crystal ingot 10 is realized by the moving platform 101 during the detection and identification to realize full-area detection and identification of the semiconductor crystal ingot 10.

[0068] The light source assembly 31 can be configured with a detection laser 311, a polarizer 312, and a condenser lens 313 arranged in sequence along the light path. The detection laser 311 is used to emit detection laser light. The polarizer 312 is used to unify the incident light polarization state to be horizontal linear polarization. The condenser lens 313 is used to focus the polarized light.

[0069] The imaging system 32 can be configured with a semi-transmissive semi-reflective mirror 321, an objective lens 322, a 1 / 4 wave plate 323, an analyzer 324, a focusing lens 325, and a CCD camera 326 arranged in sequence along the light path. The semi-transmissive semi-reflective mirror 321 is used to reflect 50% of the incident light to vertically irradiate the semiconductor crystal ingot 10 and transmit 50% of the reflected light of the semiconductor crystal ingot 10 to vertically enter the objective lens 322 to collect more emission light information in the same light path. The objective lens 322 is used to collect the light reflected by the semi-transmissive semi-reflective mirror 321, amplify the information carried by the reflected light, and form an image. The 1 / 4 wave plate 323 is used to convert the linear polarization of the reflected light of the semiconductor crystal ingot 10 to elliptical polarization to enhance the polarization difference between the original facet area 10a0 and the non-facet area 10b. The analyzer 324 is used to filter the reflected light of the non-facet area 10b (dark state) and retain the reflected light of the original facet area 10a0 (bright state) to form a contrast image. The focusing lens 325 is used to transfer the image amplified by the objective lens 322 to the target surface of the CCD camera 326 to match the pixel size. The CCD camera 326 is used to collect the reflected light image and output the imaging result.

[0070] In some embodiments, the semiconductor ingot 10 can be directly laser modified based on the imaging result of the original facet region 10a0.

[0071] Since the shape of the original facet region 10a0 is usually irregular (for example, oval, polygon, etc.), to improve the modification efficiency and effect of the semiconductor ingot 10, embodiments of the present application propose a method for adaptively optimizing and constructing the boundary of the original facet region 10a0, as shown in Figure 4 , which specifically includes the following steps: S11-S13.

[0072] S11, using a laser detection device configured with an imaging system to detect the semiconductor ingot to obtain an imaging result.

[0073] For example, using a laser detection device 30 configured with an imaging system 32 as shown in Figure 3 to detect the semiconductor ingot 10 to obtain an imaging result as shown in Figure 5 (a).

[0074] S12, according to the imaging result, identifying the boundary of the original facet region 10a0 of the semiconductor ingot 10.

[0075] For example, according to the imaging result as shown in Figure 5 (a), the darker region is identified as the non-facet region 10b, and the brighter region is identified as the original facet region 10a0. Wherein, the boundary of the original facet region 10a0 is elliptical.

[0076] S13, constructing a rectangular region according to the maximum value data of the length and width of the boundary, determining the rectangular region as a facet region, and performing laser modification based on the facet region.

[0077] Taking the major axis of the oval as the length and the minor axis as the width, a rectangular region as shown in Figure 5 (b) is constructed, and the rectangular region is determined as a facet region 10a, and other regions are determined as non-facet regions 10b. Further, the parameter data of the facet region 10a and the non-facet region 10b is stored for subsequent call processing.

[0078] Although there is a certain non-facet material in the facet region 10a, since the material damage threshold has a certain interval, the single laser energy is limited, and when the sub-beam for facet region 10a modification scans the small part of non-facet material in the facet region 10a, the internal micro-crack propagation caused by it will not be excessively deep in the longitudinal direction, and the influence on the overall wafer peeling can be ignored.

[0079] Referring to Figure 6As shown, the optimization method of the facet region boundary self-adaption can be realized by the region determination module, which can be integrated in the controller 220 of the laser modification device 20, or configured in the laser detection device 30, and the controller 220 directly obtains the identification result of the facet region 10a by data transmission with the laser detection device 30.

[0080] It can be understood that the steps S11-S13 exemplified above are one possible way to determine the facet region of the semiconductor ingot, and other ways to determine the facet region of the semiconductor ingot are not exhaustive and should be within the protection scope of the present application.

[0081] In step S2, the material layer at the preset depth position of the semiconductor ingot is subjected to laser modification processing, including: processing the material layer in the facet region based on the first laser parameter, and processing the material layer in the non-facet region based on the second laser parameter; the modification irradiation energy corresponding to the first laser parameter is greater than the modification irradiation energy corresponding to the second laser parameter.

[0082] Referring to Figure 6 As shown, after the facet region 10a of the semiconductor ingot 10 is detected and imaged, the semiconductor ingot 10 is transferred from the detection station 301 to the modification station 201 by the moving platform 101, and waits for laser modification processing.

[0083] In some embodiments, the semiconductor ingot 10 is subjected to laser modification by the laser modification device 20. The laser modification device 20 is configured with a controller 220 to realize functions such as dynamic adjustment of multi-dimensional processing parameters, synchronous coordination of multi-axis motion control system, real-time analysis and optimization of processing data, etc.

[0084] For the construction of the laser modification optical system, for example, it can be constructed as follows: a modification laser 210 is configured to emit an original laser beam 21 (usually a single beam), the original laser beam 21 emitted by the modification laser 210 is expanded by an expansion mirror 22, and then combined with a spatial light modulator (SLM) 23 and a 4f system 24 for beam splitting and modulation. After the modulation, the plurality of sub-beams are guided by a mirror group 25 and focused by a focusing mirror 26, and then irradiate the incident surface of the semiconductor ingot 10 to modify the preset depth position of the semiconductor ingot 10. For example, referring to Figure 8 As shown in (a) and (b) of FIG. 11, the focusing is at the preset depth h position of the semiconductor ingot 10.

[0085] The beam expander 22 is used to expand the spot diameter of the original laser beam 21 emitted by the modified laser 210. The beam emitted from the beam expander 22 can better cover the photosensitive area of the spatial light modulator 23, so as to achieve better beam shaping effect.

[0086] The spatial light modulator 23 is used to split and shape the original laser beam 21 to generate a plurality of sub-beams with different focal points. For example, by using the spatial light modulator 23 to modulate the phase of the incident laser, the incident laser is split into a plurality of sub-beams with different curvature centers and directions. Taking an example of splitting a beam into two sub-beams, the essence of generating two different focal points is to split and recombine the wavefront of a laser beam. The focal point 1 and the focal point 2 correspond to two different spherical waves, and finally focus on different positions in the modified part.

[0087] The phase delay required to make the focal point at the position (x1, y1, z1) is:

[0088]

[0089] wherein,

[0090] Φ1(x, y): represents the phase modulation required to be applied at the point (x, y) on the spatial light modulator 23;

[0091] (x, y): position coordinates on the spatial light modulator 23, with the center point of the spatial light modulator 23 as the origin;

[0092] λ: wavelength of the incident laser;

[0093] (x1, y1, z1): position coordinates of the first focal point;

[0094] z ref : reference distance, usually selected as the focal length or the average distance of the focal points of the system.

[0095] The first term of the formula is the geometric distance from the point (x, y) on the spatial light modulator 23 to the focal point (x1, y1, z1), and the second term is the distance from the point (x, y) on the SLM to the reference point. The difference between the two is multiplied by 2π / λ to convert it into a phase difference. Under the paraxial approximation condition, the spherical wave can be approximated by a parabolic surface, thereby simplifying the calculation. Therefore, the phase in the Z direction can be represented as Φ lens1 (x, y), which satisfies the following expression:

[0096] Φ lens1 (x, y) = -(π / (λ·f1))·(x 2 +y 2 ), (2)

[0097] wherein, the negative sign represents a converging lens, and f1 represents the focal length of the focusing lens 26;

[0098] The phase in the XY direction can be expressed as Φ prism1 (x,y), satisfying the following expression:

[0099] Φ prism1 (x,y) = (2π / λ) · (θ x1 · x + θ y1 · y), (3)

[0100] where θ x1 = arctan(x1 / f1), θ y1 = arctan(y1 / f1), (4)

[0101] Φ lens1 (x,y) generates a spherical wave front, controlling the beam convergence / divergence.

[0102] Φ prism1 (x,y) generates a tilted wave front, controlling the beam deflection direction.

[0103] Thus, the total phase is:

[0104] Φ1(x,y) = Φ lens1 (x,y) + Φ prism1 (x,y), (5)

[0105] This formula decomposes the complex spherical wave phase into a simple combination of quadratic function (lens) and linear function (prism), and the required phase delay for the focal point located at (x2, y2, z2) is the same. Next, the two wave front phases are superimposed:

[0106] Φ SLM (x,y) = arg[w1·exp(i·Φ1(x,y)) + w2·exp(i·Φ2(x,y))], (6)

[0107] w1, w2: weight coefficients of the two focal points, used to control the light intensity of the focal points, where:

[0108]

[0109] arg[·]: take the phase angle operation of complex number, extract the phase of the complex field as the final phase of the SLM;

[0110] exp(i·Φ n (x,y)): is to convert the phase into a complex exponential form;

[0111] Since the phase modulation range of the spatial light modulator 23 is 0-2π, the result after phase superposition calculation needs to be ensured within the range of 0-2π:

[0112] Φ = mod(Φ SLM (x,y),2π, (9)

[0113] By calculating one by one, the phase delay required to be displayed by different pixel points on the spatial light modulator 23 can be known, so that the incident plane wave is finally modulated into two different wave fronts, which are respectively converged to two target focal points.

[0114] 4f system 24: for example, constructed by using a first lens 241 and a second lens 242, the spatial light modulator 23 provides an ideal Fourier transform platform, which can efficiently modulate the light field.

[0115] Reflector group 25: for example, constructed by using four mirrors, wherein the first mirror 251 functions to turn the light beam in space, which can reduce the volume of the overall optical path; the second mirror 252 and the third mirror 253 are used to lift the laser light path in space, which facilitates the subsequent vertical action of the laser on the surface of the semiconductor crystal ingot 10; the fourth mirror 254 folds the laser lifted by the second mirror 252 and the third mirror 253, so that the laser is vertically incident during processing.

[0116] Focusing mirror 26: realizes laser focusing, which can be adjusted by adjusting the relative height between the focusing mirror 26 and the semiconductor crystal ingot 10.

[0117] The embodiment of the present application can realize precise control of the number, energy and spacing of the laser beams by introducing the spatial light modulator 23 into the laser modification light path, solve the problem that the single laser beam cannot match the transmittance and material damage threshold of the semiconductor crystal ingot in the current laser modification process, and at the same time, the small area region 10a is modified more accurately, and the incomplete modification phenomenon caused by material properties is improved.

[0118] In combination with Figure 7 As shown in the figure, the method provided by the present application for laser modification processing of a material layer of a semiconductor crystal ingot at a preset depth position specifically comprises the following steps: S21-S23.

[0119] Step S21, obtain the processing parameters and the movement mechanism of laser scanning.

[0120] Based on the data such as the material properties of the semiconductor crystal ingot 10 to be modified, the morphology of the small area region 10a and the non-small area region 10b, the corresponding processing parameters and the movement mechanism of laser scanning are configured in the controller 220. The processing parameters and the movement mechanism of laser scanning can be retrieved from the existing database, or can be set immediately according to the material properties and morphological characteristics of the crystal ingot to be modified.

[0121] Since the transmittance of the facet region 10a is lower than that of the non-facet region 10b, when the laser energy can modify the non-facet region 10b, due to the lower transmittance, the same laser energy cannot effectively modify the facet region 10a. Therefore, in this application, a regional differential modification method is proposed for the facet region 10a and the non-facet region 10b, and the laser irradiation energy is enhanced according to the material properties of the facet region 10a to achieve accurate modification.

[0122] Therefore, for the configuration of the processing parameters of the laser modification device 20 provided in this application, including but not limited to:

[0123] ① The parameters of the original laser beam 21 emitted by the modification laser 210;

[0124] ② The first laser parameters for modifying the material layer in the facet region 10a, and the second laser parameters for modifying the material layer in the non-facet region 10b;

[0125] ③ The depth to be modified of the semiconductor ingot 10, and the height of the focusing mirror 26 corresponding thereto;

[0126] ④ The movement performance parameters of the moving platform 101, including stroke, step distance, dynamic performance, etc.

[0127] Since the laser modification is to focus the laser inside the semiconductor material, it is subject to the transmittance of the material, so the laser power needs to be stabilized in a suitable range to avoid damaging the surface layer of the semiconductor ingot 10.

[0128] For example, in some embodiments, the original laser beam 21 can use pulsed laser with wavelength range of 532nm (nanometer) ~ 1064nm, pulse frequency of 100kHz (kilohertz) ~ 2000kHz, power of 20w (watt) ~ 80w, and pulse width including picosecond level and femtosecond level, wherein the pulse width range of picosecond level is 10 picoseconds ~ 300 picoseconds, and the pulse width range of femtosecond level is 500 femtoseconds ~ 800 femtoseconds. Combined with Figure 6 、 Figure 8 (a) ~ (b) and Figure 9 When the laser scanning region is the facet region 10a, the spatial light modulator 23 modulates based on the first laser parameters to obtain a plurality of first sub-beams 211a, and the plurality of first sub-beams 211a are arranged to form a first sub-beam unit 21a; the first laser parameters include: the arrangement density of the first sub-beams 211a, and the first power corresponding to a single first sub-beam 211a.

[0129] When the laser scanning region is the facet region 10a, the spatial light modulator 23 modulates based on the first laser parameters to obtain a plurality of first sub-beams 211a, and the plurality of first sub-beams 211a are arranged to form a first sub-beam unit 21a; the first laser parameters include: the arrangement density of the first sub-beams 211a, and the first power corresponding to a single first sub-beam 211a.

[0130] When the laser scanning region is the non-facet region 10b, the spatial light modulator 23 modulates based on the second laser parameters to obtain a plurality of second sub-beams 211b, which are arranged to form a second sub-beam unit 21b; the second laser parameters include: arrangement density of the second sub-beams 211b, and the second power corresponding to a single second sub-beam 211b.

[0131] The modification irradiation energy for laser scanning the facet region 10a is configured to be greater than the modification irradiation energy for laser scanning the non-facet region 10b. In the non-facet region 10b, a laser sub-beam with a larger spacing, fewer number, and lower energy is applied to reduce modification damage; in the facet region 10a, the spacing between the laser sub-beams is narrowed, and the number and energy of the laser sub-beams are increased to complete the precise modification of this specific region. For example, the arrangement density of the first sub-beams 211a is configured to be greater than the arrangement density of the second sub-beams 211b, and the first power is configured to be greater than the second power.

[0132] In some embodiments, the spacing d1 between the first sub-beams 211a is configured to be 80 μm to 120 μm, and the first power is configured to be 14 w to 16 w; the spacing d2 between the second sub-beams 211b is configured to be 180 μm to 220 μm, and the power of a single beam is configured to be 11 w to 13 w.

[0133] For example, the depth to be modified of the semiconductor ingot 10 is configured to be a depth h, and according to the depth h and the first laser parameters and the second laser parameters, the controller 220 can automatically calculate the corresponding height of the focusing mirror 26, and control the focusing mirror 26 to move to the height.

[0134] In the laser modification process, the movement mechanism of laser scanning includes the following ways:

[0135] ① Only moving the stage: changing the relative position of the semiconductor ingot 10 and the laser beam splitting (for example, the first sub-beam unit 21a or the second sub-beam unit 21b) through the stage (for example, the moving platform 101), which belongs to mechanical movement;

[0136] ② Only adjusting the laser light path: adjusting the focal point position of the laser beam through the components in the laser light path (such as spatial light modulator, or additional deflector, galvanometer, etc.), which belongs to optical or electronic movement;

[0137] ③ Combination of moving the stage and adjusting the light path: combination of the above two movement methods to achieve more efficient or more complex scanning path;

[0138] ④ Direct coverage without movement: When the scanning area is large enough to cover the entire incident surface, the "scan" can be completed without any relative movement. This can be regarded as a special "movement mode" (i.e., zero movement).

[0139] Regardless of the scanning method used, the core principle is to achieve scanning coverage by changing the relative position between the focal point of the laser beam and the incident surface of the semiconductor ingot 10, so as to modify the entire processing layer at the preset depth position of the semiconductor ingot 10.

[0140] In some embodiments, the scanning path of the laser scan is configured to perform a relative movement with orientation and controllable distance along at least one of a first coordinate direction and a second coordinate direction, wherein the plane containing the first coordinate direction and the second coordinate direction is perpendicular to the depth direction. For example, referring to... Figure 9 and Figure 10 As shown, the laser scanning path L is configured as a "serpentine path", and the movement mechanism is configured to orient along the X and Y directions and move relative to each other according to the set step distance. The step distance of the laser scanning is matched with the spacing between the focal points of the sub-beams after beam splitting and shaping.

[0141] For example, refer to Figure 10 As shown, multiple first sub-beams 211a are arranged linearly at equal intervals to form first sub-beam units 21a, and are aligned in a direction perpendicular to the scanning path L during laser scanning. In the facet region 10a, the first step distance D1 of the laser scanning is configured to be equal to the spacing between adjacent first sub-beams 211a.

[0142] Multiple second sub-beams 211b are arranged linearly at equal intervals to form second sub-beam units 21b, and are aligned in a direction perpendicular to the scanning path L during laser scanning. In the non-facet region 10b, the second step distance D2 of the laser scanning is configured to be equal to the spacing between adjacent second sub-beams 211b.

[0143] In other embodiments, the plurality of first sub-beams 211a may also be arranged in a matrix, and the plurality of second sub-beams 211b may also be arranged in a matrix. Within the facet region 10a or the non-facet region 10b, the step distance of the laser scanning is matched with the length of the rectangle formed by the plurality of first sub-beams 211a or the plurality of second sub-beams 211b, respectively.

[0144] Furthermore, in some embodiments, on the same X-direction cutting line, the focal points of different sub-beams are made to act on the same coordinate position in the Y-direction during laser scanning, so the moving platform 101 only needs to move in the X-direction by the corresponding step distance.

[0145] For example, combining Figure 9 and Figure 10As shown, the maximum spacing between the first sub-beam unit 21a and the second sub-beam unit 21b in the direction perpendicular to the scanning path L is set to be the same, i.e., as shown in the figure. Figure 10 In this case, the scanning path L is located in the X direction. The maximum spacing between the first sub-beam unit 21a and the second sub-beam unit 21b in the Y direction is the same. Therefore, after switching the laser parameters (i.e., in one processing step, for the small facet region 10a and the non-small facet region 10b), it is not necessary to adjust the position along the Y direction. Only the step distance in the X direction needs to be adjusted (for example, when scanning from the non-small facet region 10b to the small facet region 10a, the step distance D2 corresponding to the second sub-beam unit 21b is switched to the step distance D1 corresponding to the first sub-beam unit 21a). This allows for continuous scanning and cutting along the preset path L in the X direction without adjusting the position in the Y direction.

[0146] Matching the step distance of laser scanning with the spacing between the focal points of the sub-beams after beam splitting and shaping ensures seamless connection between adjacent processing areas. The laser energy distribution in the small facet region 10a and the non-small facet region 10b is uniform, further enabling local melting and microcrack formation within the material, thereby forming a complete and continuous modified layer at a preset depth.

[0147] Step S22: Perform full-area laser scanning on the semiconductor ingot to form a modified layer at a preset depth. The small facet area is scanned using the first laser parameter, and the non-small facet area is scanned using the second laser parameter.

[0148] For example, refer to Figure 8 As shown in (a) and (b), the target modification depth of the semiconductor ingot 10 is at depth h.

[0149] During the laser refining process, the focusing lens 26 focuses the first sub-beam 211a onto the material layer in the facet region 10a at depth h of the semiconductor ingot 10, and focuses the second sub-beam 211b onto the material layer in the non-facet region 10b at depth h of the semiconductor ingot 10, so as to refining the entire material layer at depth h, for example, forming an amorphous refining layer 11 or forming a refining layer 11 with dislocation networks, cracks, etc., to facilitate physical separation.

[0150] The laser modification device 20 automatically adjusts the output power and the laser beam splitting effect of the modification laser 210 during the processing according to the previously determined facet region 10a, and uses more intensive sub-beams for modification in the facet region 10a. The facet region 10a can adopt the same number of scans as the non-facet region 10b, without the need for additional repeated scans relative to the non-facet region 10b, so that a complete semiconductor modification layer can be formed inside the semiconductor crystal ingot 10. This facilitates subsequent faster and less damaging physical separation, effectively improving the material utilization and processing efficiency of the semiconductor original crystal ingot.

[0151] In most application scenarios, a continuous and complete semiconductor modification layer can be formed inside the semiconductor crystal ingot 10 by only a single modification.

[0152] Determining whether the target modification layer of the semiconductor crystal ingot 10 is uniformly modified as expected can be achieved by verifying whether it can be separated based on the modification layer by using the same thermo-chemical, physical-mechanical or ultrasonic means as the semiconductor crystal ingot modified by the conventional method, or more efficiently. Alternatively, in some embodiments, it can also be determined by specific indicators, such as controlling the modification layer depth, hardness or microstructure difference indicators within a small difference range (e.g. ±5%), to achieve performance uniformity, so as to facilitate the whole layer peeling of the modification layer.

[0153] Step S23, immersing the modified semiconductor crystal ingot in a liquid medium for ultrasonic vibration, so that the semiconductor crystal ingot is separated based on the modification layer to obtain a separated semiconductor wafer.

[0154] The modified semiconductor crystal ingot 10 is placed in an ultrasonic peeling device (not shown) using the principle of ultrasonic working. The peeling medium is normal temperature water, and the ultrasonic parameters are, for example, a frequency of 28 kHz or 40 kHz, a power of 600w-1000w, and a peeling time of 5min-40min.

[0155] The ultrasonic cavitation correspondingly accelerates the propagation and rupture of micro-cracks inside the modification layer, and the semiconductor wafer is obtained. The semiconductor wafer can be used for subsequent grinding and polishing to prepare semiconductor substrate materials or semiconductor optical products. For example, the semiconductor substrate can be used to form a wafer with a diameter of 2 inches-12 inches. Alternatively, a semiconductor seed crystal or a semiconductor substrate can be formed based on the semiconductor wafer.

[0156] The laser focusing depth (i.e. the preset depth) has a positive correlation with the thickness of the semiconductor wafer after peeling and the thickness of the semiconductor crystal ingot. The thickness of the semiconductor wafer can be freely selected and determined to improve the utilization rate of the semiconductor crystal ingot.

[0157] The modification method is suitable for cutting of conductive silicon carbide ingot and silicon carbide wafer material, and also suitable for cutting of semi-insulating or high-purity silicon carbide ingot and silicon carbide wafer material. It is also suitable for cutting of other semiconductor ingots containing facet regions.

[0158] Compared with the existing modification technology under the condition of a single laser parameter, the modification efficiency can be increased by at least 3 times, the material utilization rate of the semiconductor ingot is increased by more than 30%, the subsequent ultrasonic separation speed is increased by 30%, and the crack risk is less than 1%.

[0159] In combination Figure 11 The laser modification processing of a silicon carbide ingot (conductive 4H-SiC ingot, diameter of 8 inches, thickness of 20 mm) is taken as an example for specific description.

[0160] Step S31: Surface smoothing treatment is performed on the silicon carbide ingot.

[0161] Both the carbon surface and the silicon surface of the silicon carbide ingot can be used as the processing surface for laser incidence. In this embodiment, the carbon surface of the silicon carbide ingot is used as the incidence surface, and therefore, the carbon surface of the silicon carbide ingot is ground, for example, by using a high-precision diamond grinding wheel, so that the surface roughness is controlled to be less than 10 nm. Such a smooth silicon carbide surface can reduce the reflection of incident laser, thereby improving the utilization efficiency of the output energy of the laser and reducing the thermal effect in the cutting process.

[0162] Step S32: The silicon carbide ingot is positioned on the moving platform 101, and the facet region of the silicon carbide ingot is identified by the laser detection device 30.

[0163] The silicon carbide ingot is fixed on the porous ceramic base by using the adsorption principle of the vacuum porous ceramic disc, and the ceramic base is fixed on the moving platform 101, so as to ensure that the silicon carbide ingot is fixed relative to the ceramic disc during the whole processing process and the modification accuracy is ensured.

[0164] The facet region of the ingot is detected by the laser detection device 30, and the detection laser 311 uses a green laser with a wavelength of 532 nm and an output power of 3 mw. The moving platform 101 reciprocates in a "serpentine path", and the images are continuously collected by the CCD camera 326. After the overall scanning is completed, the position of the facet is determined according to the images collected by the CCD camera 326.

[0165] Step S33: The facet region of the silicon carbide ingot is determined.

[0166] The imaging result collected by the CCD camera 326 is as follows: Figure 5The gray scale map of "non-facet area 10b dark + original facet area 10a0 bright" shown in (a). Through the method of adaptively optimizing the boundary of the facet area 10a proposed in this application, the improved gray scale map as shown in (b) is obtained. Figure 5 The facet area 10a and the non-facet area 10b shown in (b).

[0167] Step S34: Set the machining parameters and scanning movement mechanism.

[0168] In the machining software of the electronic device in communication with the controller 220, the laser beam splitting effect and the beam spacing are set. A double-beam with a spacing of 200 μm is set in the non-facet area 10b, and the single-beam energy is set to 12 w. A four-beam with a spacing of 100 μm is set in the facet area 10a, and the single-beam energy is set to 15 w.

[0169] The movement mechanism is to change the relative position of the semiconductor crystal ingot 10 and the laser beam splitting (for example, the first sub-beam unit 21a or the second sub-beam unit 21b) by moving the platform 101, so that the laser is scanned along the scanning path L by the carbon face (upper surface) of the silicon carbide crystal ingot as the incident surface.

[0170] The machining is performed using a pulse laser with transmittance to the silicon carbide crystal material, such as a wavelength of 1064 nm, a pulse frequency of 100 kHz, a pulse width of 15 picoseconds, and a total laser power determined by the total number of beams and the single-beam energy of different areas.

[0171] The focal point is focused on a certain specific height inside the silicon carbide crystal ingot by moving the Z-axis of the focusing mirror 26, which is generally 250 μm to 450 μm. The laser focusing position and the final wafer thickness show a certain linear relationship, which can be set according to actual needs.

[0172] Step S35: Perform full-area laser scanning on the silicon carbide crystal ingot to obtain an improved silicon carbide crystal ingot.

[0173] The laser modification process is started, and the system will automatically change the laser beam splitting effect during the machining process according to the facet data collected in the early stage, and simultaneously change the laser output power to ensure that the average power of each focal point is consistent. In order to improve the facet modification efficiency, in the machining process, the system will automatically match the machining path according to the size of the whole semiconductor crystal ingot, the facet position, the number of beam splitting focal points and the spacing.

[0174] After a single scan is completed, a complete modified silicon carbide crystal ingot is obtained.

[0175] Step S36: Ultrasonic separation of the modified silicon carbide crystal ingot.

[0176] The complete modified silicon carbide ingot is placed in an ultrasonic cleaning machine for ultrasonic separation. Due to the cavitation effect of the ultrasonic waves, the micro-cracks formed in the ingot due to the modification are further extended and connected, and finally the complete physical separation of the silicon carbide ingot and wafer is achieved, and the silicon carbide wafer is obtained.

[0177] The obtained silicon carbide wafer can be observed by microscopy to observe the modification effect of the modified layer. For example, referring to Figure 12 The presented partial schematic diagram of the modified layer of the silicon carbide ingot modified by laser and ultrasonic peeling of the modified layer is observed under a microscope, which has a series of parallel arranged stripe structures, the colors of the stripes present orange and other color gradients, the spacing between the stripes is relatively uniform, and the overall arrangement is neat, such structure characteristics belong to the characteristics of continuous amorphous modified layer.

[0178] Step S37: grinding and polishing to obtain a standard size silicon carbide substrate.

[0179] After subsequent grinding and polishing, an 8-inch silicon carbide substrate product meeting the standard thickness of 350 μm is formed.

[0180] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present application, and are not intended to limit the protection scope of the present application. Any equivalent embodiments or changes made without departing from the spirit of the present application shall be included in the protection scope of the present application.

[0181] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims.

[0182] In addition, it should be understood that although the present specification is described in terms of embodiments, each embodiment does not contain only one independent technical solution, and the description manner of the specification is only for clarity, those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments which can be understood by those skilled in the art.

Claims

1. A laser modification method for semiconductor ingots, characterized in that, include: Determine the facet region of the semiconductor ingot; Laser modification of the material layer at a preset depth position of the semiconductor ingot includes: processing the material layer in the small facet region based on a first laser parameter, and processing the material layer in the non-small facet region based on a second laser parameter; The modified irradiation energy corresponding to the first laser parameter is greater than the modified irradiation energy corresponding to the second laser parameter.

2. The method according to claim 1, characterized in that, Laser modification treatment is performed on the material layer of the semiconductor ingot at a predetermined depth, including: Based on a spatial light modulator, the original laser beam emitted by the laser is beam shaped to generate multiple sub-beams with different focal points; wherein, the spatial modulator modulates the phase of the original laser beam, causing the original laser beam to split into multiple sub-beams with different wavefronts. Based on multiple sub-beams, the material layer of the semiconductor ingot at a preset depth is subjected to laser modification treatment to obtain a modified layer.

3. The method according to claim 2, characterized in that, The small facet region is modulated based on the first laser parameters to obtain multiple first sub-beams; the first laser parameters include: the arrangement density of the first sub-beams and the first power corresponding to a single first sub-beam; The non-small facet region is modulated based on the second laser parameters to obtain multiple second sub-beams; the second laser parameters include: the arrangement density of the second sub-beams and the second power corresponding to a single second sub-beam; The arrangement density of the first sub-beam is greater than that of the second sub-beam, and the first power is greater than the second power.

4. The method according to any one of claims 1-3, characterized in that, The determination of the facet region of the semiconductor ingot includes: A laser detection device equipped with an imaging system is used to detect the semiconductor ingot, obtaining imaging results; based on the differences in the imaging results, the boundaries of the original facet regions of the semiconductor ingot are identified; a rectangular region is constructed based on the maximum and minimum values ​​of the length and width of the boundaries, and the rectangular region is determined to be the facet region; or... The identification results of small facet regions are obtained from a laser detection device equipped with an imaging system; Preferably, the method further includes: A first laser parameter is set for the facet region of the semiconductor ingot, and a second laser parameter is set for the non-facet region. Preferably, the material layer of the semiconductor ingot at a predetermined depth is subjected to laser modification treatment, including: A full-area laser scan is performed on a semiconductor ingot, and the original laser beam is split and shaped according to the type of the laser scanning area by matching the first laser parameters or the second laser parameters. Specifically, when the laser scanning area is the facet region, the original laser beam is shaped into multiple first sub-beams according to the first laser parameters; when the laser scanning area is not the facet region, the original laser beam is shaped into multiple second sub-beams according to the second laser parameters. The first sub-beam is focused on the material layer in the small facet region of the semiconductor ingot at a preset depth position, and the second sub-beam is focused on the material layer in the non-small facet region of the semiconductor ingot at a preset depth position to form a modified layer. Preferably, the semiconductor ingot includes at least one of the following: silicon carbide ingot, gallium nitride ingot, and gallium arsenide ingot.

5. The method according to claim 4, characterized in that, During the laser modification process, the same number of laser scans are performed on the small facet area as on the non-small facet area to form the modification layer on the entire processing plane at a predetermined depth position of the semiconductor ingot.

6. The method according to claim 5, characterized in that, The scanning path of the laser scan is configured as follows: relative movement with directional and controllable distance along at least one of the first coordinate direction and the second coordinate direction, wherein the plane containing the first coordinate direction and the second coordinate direction is perpendicular to the depth direction; The laser scanning movement mechanism includes: moving the stage and / or adjusting the laser optical path, wherein the step distance of the laser scanning is matched with the spacing between the focal points of the sub-beams after beam splitting and shaping.

7. The method according to claim 3, characterized in that, The method further includes at least one of the following: The spacing between the first sub-beams is 80μm to 120μm, and the first power is 14W to 16W; the spacing between the second sub-beams is 180μm to 220μm, and the power of a single beam is 11W to 13W; or, The original laser beam uses a pulsed laser with a wavelength range of 532nm to 1064nm, a pulse frequency of 100kHz to 2000kHz, a power of 20W to 80W, and pulse widths ranging from picoseconds to femtoseconds. Specifically, the picosecond pulse width ranges from 10 picoseconds to 300 picoseconds, and the femtosecond pulse width ranges from 500 femtoseconds to 800 femtoseconds; or... The semiconductor ingot is surface-smoothed so that the surface roughness corresponding to the surface penetrated by the laser incident direction is below 10 nm; or... The modified semiconductor ingot is immersed in a liquid medium and subjected to ultrasonic vibration, which causes the semiconductor ingot to separate based on the modified layer to obtain a separated semiconductor wafer; a wafer with a diameter of 2 inches to 12 inches is formed based on the semiconductor wafer, or a semiconductor seed or semiconductor substrate is formed based on the semiconductor wafer.

8. The method according to any one of claims 2-3, characterized in that, A laser refining optical path system is constructed to perform laser refining treatment on the material layer of the semiconductor ingot at a predetermined depth. The laser refining optical path system is constructed as follows: The original laser beam emitted by the laser is expanded by a beam expander, then split and modulated by a combination of a spatial light modulator and a 4f system. The modulated sub-beams are then guided by a reflector group and focused by a focusing lens before illuminating the incident surface of the semiconductor ingot.

9. A laser modification device for semiconductor ingots, characterized in that, include: The region determination module is used to determine the facet regions of a semiconductor ingot; A laser-modified optical path system is used to perform laser modification treatment on the material layer of the semiconductor ingot at a preset depth position, including: processing the material layer in the small facet area based on a first laser parameter, and processing the material layer in the non-small facet area based on a second laser parameter; The modified irradiation energy corresponding to the first laser parameter is greater than the modified irradiation energy corresponding to the second laser parameter.

10. The apparatus according to claim 9, characterized in that, Also includes: A spatial light modulator, configured in the laser refining optical path system, is used to shape the original laser beam emitted by the laser based on the first laser parameters or the second laser parameters to generate multiple sub-beams with different focal points. The controller is used to receive input from the region determination module and adjust the laser quality improvement optical path system to match the processing parameters, including dynamically adjusting the output power of the original laser beam, dynamically switching the first laser parameter and the second laser parameter, and matching the step distance of the laser scan with the first laser parameter and the second laser parameter; Multiple sub-beams are irradiated onto the incident surface of the semiconductor ingot through the laser-modified optical path system.

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