Wafer laser grooving method and system based on polarization adjustment and spatial light modulator linkage

Abstract

The invention discloses a wafer laser grooving method and system based on linkage of polarization adjustment and a spatial light modulator. The wafer laser grooving method comprises the steps that a laser beam is adapted to the spatial light modulator through light path adjustment; the spatial light modulator loads the rectangular phase diagram to form a main light spot, a high-frequency modulation pattern is superposed on the edge, and the grooving width is adjusted by rotating the angle of the main light spot; the 4F system screens the frequency spectrum and restores a composite light field containing a main light spot and auxiliary sub-light spots on the two sides; a single pulse is staged, and the spatial light modulator synchronously regulates and controls light spot parameters; after the objective lens is focused, the main light spot cuts the channel and assists the sub-light spots in softening the edge. The problems that a traditional method is poor in edge quality, low in efficiency and the like are solved, the grooving precision, the edge quality and the efficiency are improved, and the method is suitable for high-precision wafer machining.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wafer cutting, and in particular to a high-precision non-destructive cutting method and system based on laser hidden cutting and laser thermal stress controlled fracture cutting technology. BACKGROUND

[0002] With the continuous development of semiconductor manufacturing technology, wafer cutting precision and edge integrity put forward higher requirements on chip yield and packaging reliability. Traditional mechanical blade cutting, laser thermal cleavage and green laser cutting methods face a series of challenges in practical application, such as large cutting stress, many edge micro-cracks, wide heat-affected zone and difficult to control cutting path, etc. Laser grooving technology as a key process for the machining of precision devices such as wafers, its core is to form a groove of a certain size on the surface of the material by laser beam, to meet the electrical isolation, heat dissipation or packaging requirements of the device. With the development of the semiconductor industry towards high density and miniaturization, wafer grooving has increasingly stringent requirements on width precision, edge quality and processing efficiency.

[0003] In recent years, pulsed laser cutting has gradually become an important means in the field of wafer grooving due to its non-contact, high precision and small heat-affected characteristics. However, existing laser cutting technology mainly uses fixed spot morphology and single energy distribution, which is difficult to balance cutting depth control and edge quality optimization, especially when dealing with high brittleness materials such as silicon and gallium arsenide, micro-cracks and edge collapse defects are easily formed on the edge of the groove, which seriously affects the performance of the device. SUMMARY

[0004] (I) Technical problems solved

[0005] To solve the problems in the prior art, the application provides a wafer laser slotting method and system based on polarization adjustment and spatial light modulator linkage, aiming to solve the problems of edge micro-cracks, edge collapse and uncontrollable thermal influence in the existing laser cutting. The method introduces a spatial light modulator (SLM) to dynamically shape and frequency-domain control the laser light field, realizing the composite configuration of the main spot and the auxiliary sub-spot: the main spot has high energy density and is used for core cutting, and the two auxiliary sub-spots with lower energy are used for synchronous pre-softening treatment of the edge of the cutting path, thereby significantly reducing the material fracture stress and edge defect risk. The system adopts polarization adjustment and SLM pattern loading cooperative control, converts the SLM spatial pattern into a frequency-domain signal through a 4F system, and accurately filters and restores it, realizing high-quality imaging of the composite spot in the spatial domain. In addition, the laser pulse energy and the SLM modulation pattern are linked in nanosecond time sequence, and the spot morphology and energy distribution are switched synchronously in different stages of the laser pulse, so that the penetration, widening and trimming stages of the cutting process all have optimal light field matching. Finally, the composite light field is focused on the wafer surface with high precision through the objective lens, realizing high-energy density cutting while ensuring that the edge material is in a softened state, reducing stress concentration, avoiding edge damage, and significantly improving the cutting edge integrity and wafer yield.

[0006] (II) Technical scheme

[0007] To achieve the above-mentioned purpose, the application provides the following technical scheme: a wafer laser slotting method based on polarization adjustment and spatial light modulator linkage, the cutting method comprising the following steps:

[0008] S1. Laser beam generation and light path adaptation: the laser outputs pulsed laser, adjusts the laser beam transmission direction through the reflector, adjusts the spot size by using the beam expander, adjusts the polarization direction of the laser by using the half-wave plate, and makes the polarization direction adapt to the sensitive characteristics of the spatial light modulator;

[0009] S2. Composite pattern loading: the spatial light modulator loads a preset shape to form a main spot, and superimposes a periodic high-frequency modulation pattern on the edge of the main spot;

[0010] S3. Frequency-domain screening: the 4F system converts the composite light field output by the spatial light modulator into the frequency domain, and retains the low-frequency spectrum corresponding to the main spot and the high-frequency spectrum corresponding to the edge high-frequency modulation pattern through the filter diaphragm;

[0011] S4. Secondary imaging: the 4F system converts the screened spectrum back to the spatial domain to form a composite light field containing a main spot and auxiliary sub-spots symmetrically distributed on both sides of the main spot;

[0012] S5. Timing linkage regulation: The single pulse output by the laser is divided into multiple energy stages, and the spatial light modulator synchronously regulates the shape, angle and energy distribution of the main spot and auxiliary sub-spots in each stage, so that the composite light field matches the pulse energy variation;

[0013] S6. Focusing slotting: The objective lens focuses the composite light field on the wafer surface, and the main spot realizes slot cutting, while the auxiliary sub-spots simultaneously soften the slot edges.

[0014] Preferably, in step S1, the mirror comprises a first mirror and a second mirror, the first mirror changes the initial transmission direction of the laser beam, and the second mirror guides the laser beam adjusted by the beam expander to the half-wave plate.

[0015] Preferably, in step S2, the preset shape is a rectangle, the slot width is continuously adjustable within a preset range by rotating the angle of the rectangular spot, the energy distribution of the spot changes in a gradient manner, and the edge energy is lower than the center energy.

[0016] Preferably, in step S2, the periodic high-frequency modulation pattern is a sinusoidal ripple structure, the frequency range is 50-150 lines per mm, and it is used to form left-right symmetrically distributed auxiliary sub-spots.

[0017] Preferably, in step S3, the 4F system is composed of two convex lenses, the focal lengths of the two convex lenses are the same and the distance between them is twice the focal length, a Fourier transform spectrum plane is formed in the middle, and the filter diaphragm is arranged on the spectrum plane.

[0018] Preferably, in step S3, the filter diaphragm comprises a central low-pass filter area and a peripheral band-pass filter area, the central low-pass filter area is used to transmit the low-frequency spectrum of the main spot, and the peripheral band-pass filter area is used to transmit the high-frequency spectrum of the edge high-frequency modulation pattern.

[0019] Preferably, in step S5, the multiple energy stages include a pulse rising stage, a pulse stable stage and a pulse falling stage.

[0020] Preferably, in the pulse rising stage, the main spot adopts sharp edge design to quickly break through the material; in the pulse stable stage, the main spot width increases to widen the slot; in the pulse falling stage, the main spot edge adopts arc design to trim the slot edge.

[0021] Preferably, in step S5, the energy and distance of the auxiliary sub-spots are synchronously adjusted with the parameter changes of the main spot in each energy stage. The energy density of the auxiliary sub-spot is 20%-40% of the energy density of the main spot.

[0022] A wafer laser slotting system based on polarization adjustment and spatial light modulator linkage, comprising a laser, a first mirror, a beam expander, a second mirror, a half-wave plate, a spatial light modulator, a 4F system, a third mirror and an objective lens arranged in sequence;

[0023] The laser is arranged at the incident end of the first mirror and is used for outputting a laser beam;

[0024] The beam expander is arranged at the reflection end of the first mirror and is used for adjusting the spot size of the laser beam;

[0025] The light output end of the beam expander is provided with the second mirror, the reflection end of the second mirror is provided with the half-wave plate, and the half-wave plate is used for changing the polarization direction of the laser;

[0026] The spatial light modulator is placed at the light output end of the half-wave plate and is used for adjusting the shape and energy distribution of the laser spot and changing the slotting width by rotating the spot angle;

[0027] The light output end of the spatial light modulator is provided with the 4F system, which is used for imaging the spatial light modulator and filtering stray light in the laser;

[0028] The light output end of the 4F system is provided with the third mirror, the reflection end of the third mirror is provided with the objective lens, and the objective lens is used for focusing the laser on the product surface to slot the product surface.

[0029] Further, the spatial light modulator and the laser are connected through a synchronization signal line, the spatial light modulator receives the pulse trigger signal of the laser and switches the loaded phase pattern in less than 100 ns according to the pulse trigger signal.

[0030] (Three) beneficial effects

[0031] The application aims to provide a wafer laser slotting method and system based on polarization adjustment and spatial light modulator linkage, realize linkage control by linking spatial light modulator SLM and laser output, innovatively construct a composite laser light field of "main light spot + auxiliary sub-light spot", and realize accurate energy distribution and edge softening regulation in the wafer cutting process by cooperating with time sequence regulation and frequency domain filtering technology. Compared with the traditional laser cutting method, the application effectively relieves the problems of edge micro-cracks, edge collapse and thermal damage of high brittleness materials under the action of laser while ensuring efficient cutting. The auxiliary sub-light spot realizes preheating softening in advance on both sides of the cutting path, so that the edge material stress is reduced to a safe range, the silicon material stress is reduced from 500MPa to 150MPa, the integrity and flatness of the cutting edge are greatly improved, and the roughness can be controlled below 0.3μm, and the failure rate of subsequent cleaning, packaging and other links is reduced. The whole system is non-contact and low-thermal-impact, and the cutting width and depth can be accurately controlled, which provides an advanced laser cutting solution with high yield, low damage and intelligent adjustment for high-end chip manufacturing, microelectronic packaging and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a schematic diagram of the system architecture of the application;

[0033] Figure 2 It is a schematic diagram of the main light spot and auxiliary light spot of the application;

[0034] Figure 3 It is a slotting schematic diagram of Example 1 in the application;

[0035] Figure 4 It is a slotting schematic diagram of Comparative Example 1 in the application.

[0036] In the figure: 1-laser, 2-first mirror, 3-beam expander, 4-second mirror, 5-half wave plate, 6-spatial light modulator, 7-4F system, 8-third mirror, 9-objective lens. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings of the examples in the application Figure 1 -Appendix Figure 4 The technical solutions in the embodiments of the application are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0038] Example 1:

[0039] Processing object: single crystal silicon wafer with a thickness of 500μm, target slotting width of 83μm, and depth of 22μm.

[0040] The application provides a technical solution: a wafer laser slotting method based on polarization adjustment and spatial light modulator linkage, the cutting method comprising the following steps:

[0041] S1 laser beam generation and light path guidance

[0042] Laser startup and initial beam output: the laser is started according to preset parameters, and an initial laser beam is output.

[0043] Mirror adjusts light path direction: the initial laser beam is transmitted in the horizontal direction, after being reflected by the first mirror, the light path direction is changed to the vertical downward direction, so as to ensure that the laser is accurately aligned with the central optical axis of the subsequent optical assembly, and to avoid energy loss or spot distortion caused by light path deviation.

[0044] The beam expander performs coarse adjustment of the spot size and energy adaptation, and selects the expansion multiple according to the target width range: the beam expander is composed of two groups of movable lenses, and the expansion multiple of 1x-3x is switched by adjusting the lens spacing, so that the initial spot size is adjusted to match the effective modulation area of the spatial light modulator SLM.

[0045] After the laser beam is coarsely adjusted in size by the beam expander, it enters the second mirror for secondary turning of the light path, and after being reflected, the light path direction is adjusted to change from the vertical direction to the horizontal direction, and the incident end of the half-wave plate is aligned; the half-wave plate is a rotatable optical element, and the wave plate is rotated to a preset angle to adjust the polarization direction of the laser to adapt to the sensitive direction of the spatial light modulator.

[0046] S2 composite pattern loading

[0047] S21 basic main spot modulation: the spatial light modulator SLM loads a preset rectangular phase pattern to shape the incident laser into a rectangular main spot, and this main spot is used for core cutting.

[0048] S22 edge high-frequency modulation superposition: on the left and right edges of the main spot, the SLM loads a periodic high-frequency modulation pattern, specifically a sinusoidal ripple with 100 line pairs / mm, that is, the distance between adjacent stripes is 10 μm. The spatial frequency of this pattern is directly related to the target position of the auxiliary sub-spot: the higher the frequency, the denser the stripes, and the farther the corresponding peak in the frequency domain from the center, and finally the farther the sub-spot from the main spot;

[0049] Modulation depth controls sub-spot energy: the amplitude of the stripe is set to 30% of the basic phase of the main spot, so that the energy of the auxiliary sub-spot formed subsequently is 30% of the main spot, so that it neither interferes with the main spot cutting nor effectively softens the edge.

[0050] S3: 4F system converts spatial domain pattern to frequency domain and completes high-frequency component screening

[0051] Wherein the 4F system consists of two convex lenses L1 and L2 with the same focal length f and a distance of 2f, wherein the back focal plane of L1 coincides with the front focal plane of L2, forming a "Fourier transform plane", i.e. a spectral plane, which plays a key role in converting the "spatial domain spot pattern" output by the SLM into a "frequency domain spectral distribution", and selecting the key signal forming the auxiliary sub-spot through the filter diaphragm, which specifically includes the following steps:

[0052] First step: Fourier transform

[0053] After the laser passes through the spatial light modulator SLM, it carries the spatial information of the "main spot + edge high frequency modulation". First, it enters the first convex lens L1 of the 4F system. L1 converts the spatial domain spot pattern into a frequency domain spectral distribution:

[0054] Wherein the rectangular profile of the main spot belongs to "low frequency signal", which changes slowly in space, and is manifested as a strong peak value in the center region on the back focal plane of the spectral plane L1, with concentrated energy, corresponding to the basic energy of the main spot.

[0055] The edge high frequency modulation pattern, the sinusoidal ripple of 100 lines per mm, belongs to "high frequency signal", which is manifested as two secondary peak values symmetrically distributed on both sides of the center peak value on the spectral plane. The radial distance from the center to the secondary peak value is proportional to the spatial frequency of the high frequency signal: the higher the frequency, the farther the secondary peak value from the center.

[0056] Second step: spectral plane filtering: for screening auxiliary sub-spot signal

[0057] A filter diaphragm is placed on the spectral plane, the structure of which matches the modulation signal of the SLM, only retaining the "main spot low frequency signal" and "edge high frequency signal", and filtering other stray light. The filter diaphragm includes:

[0058] Central low-pass filter area: a 5mm diameter circular area with a transmittance of >90%, which allows the low frequency spectrum of the main spot to pass through, ensuring that the main spot energy is completely retained;

[0059] Two side band-pass filter areas: located outside the central area, symmetrically arranged as two annular filter bands, aligned with the spectral secondary peak values of the high frequency modulation pattern, with a transmittance of 30%-40%, allowing only the 100 lines per mm high frequency signal loaded by the spatial light modulator SLM to pass through.

[0060] S4: secondary imaging, the 4F system restores the main spot + auxiliary sub-spot in the spatial domain

[0061] After the spectral signal is screened on the spectral plane, it enters the second convex lens L2 of the 4F system, completes the inverse conversion from the "frequency domain to the spatial domain", and finally forms a composite light field on the back focal plane of L2, i.e. the entrance end of the objective lens.

[0062] The reduction process of the main spot is as follows: the central low-frequency spectrum is subjected to L2 inverse Fourier transform, and is reduced to a rectangular main spot with a size of 83 μm x 22 μm in the spatial domain, and the energy density is kept at 1.2 x 10 6 W / cm 2 .

[0063] The auxiliary sub-spot is formed as follows: the high-frequency spectrum on both sides is subjected to L2 inverse Fourier transform, and two symmetrical spots, i.e. auxiliary sub-spots, are formed in the spatial domain:

[0064] Spatial position: since the high-frequency spectrum is located on both sides of the center in the spectral plane, the auxiliary sub-spots are naturally distributed on both sides of the main spot at a distance of 3-5 μm from the edge of the main spot in the spatial domain after inverse transform;

[0065] Energy characteristics: since the transmittance of the band-pass filter is 30%-40%, the energy of the auxiliary sub-spot is 30% of that of the main spot, which is just the softening threshold of the material, so that no additional cutting is caused and the edge is pre-softened.

[0066] S5: time sequence linkage, the composite light field enters the time sequence linkage stage, and the SLM is synchronously controlled with the laser pulse

[0067] After the composite light field formed by the main spot and the auxiliary sub-spot leaves the 4F system, it enters the time sequence linkage link with the laser pulse. The single pulse output by the laser has a total pulse width of 50 ns, which is divided into three energy stages, and the SLM synchronously switches the spot parameters, so that the action of the composite light field is accurately matched with the change of the pulse energy:

[0068] (1) first stage: 0-15 ns

[0069] Laser state: the pulse energy increases from 0 to 30% of the peak value, and the energy density increases to 1.2 x 10 6 W / cm 2 , and the material surface layer is rapidly broken down.

[0070] SLM spot control:

[0071] The main spot remains rectangular with a size of 83 μm x 22 μm, but the edge slope is adjusted to <1 μm, and the energy is concentrated in the center to ensure that the material is rapidly broken down with minimum energy;

[0072] The position of the auxiliary sub-spot remains unchanged, and the energy density is synchronously increased to 3.6 x 10 5 W / cm 2 , which is 30% of that of the main spot, and the edge material of the breakdown path is pre-softened, and the temperature rises to the softening point of silicon ≈1200 K.

[0073] Action effect: the main spot breaks down an initial groove on the wafer surface with a depth of about 5 μm, and the auxiliary sub-spot synchronously softens the edge of the groove to avoid cracking due to stress concentration when the breakdown occurs.

[0074] (2) Second stage: 15-35 ns

[0075] Laser state: pulse energy keeps 50% of peak value, energy density stabilizes at 1.0 x 10 6 W / cm 2 , Widens the channel to both sides.

[0076] SLM's spot regulation:

[0077] Main spot: width increases by 5%, about 23 μm, edge slope increases to 2 μm, so that the energy transition is more gentle, and the energy distribution is expanded to both sides, the central energy is reduced to 80% of the peak value, and the edge energy is increased to 50% of the peak value;

[0078] Auxiliary sub-spot: widens synchronously with the main spot, the interval increases from 4 μm to 5 μm, and the energy density keeps 3.6 x 10 5 W / cm 2 , continues to soften the edges of the newly widened area.

[0079] The main spot widens to both sides on the basis of the initial channel, the total width reaches 80% of the target value, and the depth reaches 60% of the target value, and the auxiliary sub-spot synchronously softens the new edge to avoid tearing the material during widening, so that the edge roughness is controlled below 0.5 μm.

[0080] (3) Third stage: 35-50 ns

[0081] Laser state: pulse energy decreases from 50% of the peak value to 20%, energy density decreases to 6 x 10 5 W / cm 2 , suitable for low-energy edge trimming.

[0082] SLM's spot regulation:

[0083] Main spot: the edge is switched to an arc design with a radius of 10 μm, the energy distribution is "low in the middle and slightly high at the edge", and the edge energy is 60% of the main peak, avoiding the secondary damage of sharp edges to the processed area;

[0084] Auxiliary sub-spot: energy density decreases synchronously to 30% of the main spot, 2 x 10 5 W / cm 2 , secondary scanning of the channel side wall to smooth the burrs.

[0085] Effect: the arc edge of the main spot trims the channel side wall, and the auxiliary sub-spot weakens the residual stress, finally reducing the edge roughness from 1.2 μm to below 0.3 μm.

[0086] S6: Grooving: composite light field is focused by the objective lens and acts on the wafer surface

[0087] The composite light field after timing regulation leaves the linkage of the SLM and the laser, and enters the focusing range of the objective lens. The core role of the objective lens is to focus the composite light field to the wafer surface, so that the spot size is reduced to 1 / 10 of the original size, the energy density is further improved, and finally the slot is realized:

[0088] The energy density of the focused main spot is improved to 1.2×10 7 W / cm 2 , which instantaneously vaporizes the wafer material to form a slot body; then the energy density of the focused auxiliary sub-spot is 3.6×10 6 W / cm 2 , which acts on the edge of the main spot cutting path 0.1 μs in advance, so that the material temperature rises to 1500K, reaching a softened but not vaporized state, reducing the brittleness of the material; when the main spot cuts, the edge material has been softened by the auxiliary sub-spot, and the stress is reduced from the traditional 500MPa to 150MPa, which is lower than the yield strength of silicon 270MPa, completely avoiding cracking, and finally focusing to form a slot body; the slot type after processing is shown in Figure 2 .

[0089] Comparative Example 1: conventional slotting method

[0090] Processing object: single crystal silicon wafer same as Example 1, target parameters consistent.

[0091] Device parameters: laser same as Example 1; optical system is a traditional diaphragm shaping, fixed P-polarization, no SLM and 4F system; objective lens same as Example 1.

[0092] Specific steps: the laser outputs a laser beam, which is shaped into a single rectangular spot by a fixed diaphragm, with an energy density of 1.5×10 6 W / cm 2 ;

[0093] Three continuous pulses are used for step-by-step processing:

[0094] First pulse, energy 3mJ: break through the surface layer, the depth reaches 10 μm;

[0095] Second pulse, energy 4mJ: widen the slot, the width reaches 50 μm;

[0096] Third pulse, energy 2mJ: trim the edge;

[0097] The slot type after processing is shown in Figure 3 .

[0098] The Figure 2 picture of the slotting completed by the embodiment of the present application is shown, which shows that the slot edge is smooth and flat, without obvious burr and cracking phenomenon, the slot width is uniform, and the overall processing quality is excellent; theFigure 3 The picture of the finished slotting for Comparative Example 1 shows that there are significant burrs at the edges of the slot, and there are many cracking traces, the cracking areas expand irregularly along the edges of the slot, and the width consistency is poor. The two figures form a sharp contrast, and directly reflect the significant advantages of the present application in improving the quality of the edges of the wafer slotting.

[0099] Although embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wafer laser grooving method based on the linkage of polarization adjustment and spatial light modulator, characterized in that, Includes the following steps: S1. Laser beam generation and optical path adaptation: The laser outputs pulsed laser, the transmission direction of the laser beam is adjusted by a mirror, the size of the light spot is adjusted by a beam expander, and the polarization direction of the laser is adjusted by a half-wave plate, so that the polarization direction is adapted to the sensitive characteristics of the spatial light modulator. S2. Composite pattern loading: The spatial light modulator loads a preset shape to form the main light spot, and a periodic high-frequency modulation pattern is superimposed on the edge of the main light spot; S3. Frequency Domain Filtering: The 4F system converts the composite light field output by the spatial light modulator to the frequency domain and retains the low-frequency spectrum corresponding to the main light spot and the high-frequency spectrum corresponding to the edge high-frequency modulation pattern through the filter aperture; S4. Secondary imaging: The 4F system converts the filtered spectrum back to the spatial domain, forming a composite light field containing the main spot and auxiliary sub-spots symmetrically distributed on both sides of it; S5. Timing-linked control: The single pulse output by the laser is divided into multiple energy stages. The spatial light modulator synchronously controls the shape, angle and energy distribution of the main spot and auxiliary sub-spots in each stage, so that the composite light field matches the pulse energy change. S6. Focusing Grooving: The objective lens focuses the composite light field onto the wafer surface, the main light spot cuts the groove, and the auxiliary sub-light spot softens the groove edge simultaneously.

2. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 1, characterized in that, In step S1, the reflector includes a first reflector and a second reflector. The first reflector changes the initial transmission direction of the laser beam, and the second reflector guides the laser beam, after being adjusted by the beam expander, to a half-wave plate.

3. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 1, characterized in that, In step S2, the preset shape of the main light spot is rectangular. By rotating the angle of the light spot, the slot width can be continuously adjusted within a preset range. The energy distribution of the light spot changes in a gradient, and the energy at the edge is lower than that at the center.

4. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 1, characterized in that, In step S2, the periodic high-frequency modulation pattern is a sinusoidal wave structure with a frequency range of 50 to 150 line pairs / mm, used to form auxiliary sub-spots that are symmetrically distributed from left to right.

5. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 1, characterized in that, In step S3, the 4F system consists of two convex lenses with the same focal length and a spacing of twice the focal length, forming a Fourier transform spectrum plane in the middle, and the filter stop is set on this spectrum plane.

6. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 5, characterized in that, In step S3, the filter aperture includes a central low-pass filter region and an outer band-pass filter region. The central low-pass filter region is used to transmit the low-frequency spectrum of the main light spot, and the outer band-pass filter region is used to transmit the high-frequency spectrum of the edge high-frequency modulation pattern.

7. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 1, characterized in that, In step S5, the multiple energy stages include a pulse rising phase, a pulse stabilizing phase, and a pulse falling phase.

8. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 7, characterized in that, During the pulse rise phase, the main spot adopts a sharp edge design to quickly penetrate the material; during the pulse stabilization phase, the main spot width is increased to widen the channel; during the pulse fall phase, the main spot edge adopts an arc design to smooth the channel edge.

9. The wafer laser grooving method based on polarization adjustment and spatial light modulator linkage according to claim 1, characterized in that, In step S5, the energy and spacing of the auxiliary sub-spots are synchronously adjusted at each energy stage as the parameters of the main spot change.

10. The system of the wafer laser grooving method based on the linkage of polarization adjustment and spatial light modulator according to any one of claims 1-9, characterized in that, It includes a laser (1), a first reflector (2), a beam expander (3), a second reflector (4), a half-wave plate (5), a spatial light modulator (6), a 4F system (7), a third reflector (8), and an objective lens (9) arranged in sequence. The laser (1) is disposed at the incident end of the first reflector (2) and is used to output a laser beam; The beam expander (3) is mounted on the reflecting end of the first reflecting mirror (2) and is used to adjust the size of the laser beam spot. The beam expander (3) is provided with a second reflector (4) at the light-emitting end; the second reflector (4) is provided with a half-wave plate (5) at the reflecting end, and the half-wave plate (5) is used to change the polarization direction of the laser. The spatial light modulator (6) is placed at the light-emitting end of the half-wave plate (4) to adjust the shape and energy distribution of the laser spot, and can change the slot width by rotating the spot angle. The spatial light modulator (6) is equipped with a 4F system (7) at its light output end, which is used to image the spatial light modulator (6) and filter stray light in the laser. The 4F system (7) is provided with a third reflector (8) at the light-emitting end, and an objective lens (9) is provided at the reflecting end of the third reflector (8). The objective lens (9) is used to focus the laser on the surface of the product to make the laser product surface grooved.

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