Multi-beam laser processing device and system based on laser interference

Abstract

This invention provides a multi-beam laser processing apparatus and system based on laser interference, relating to the field of laser processing technology. The apparatus includes, arranged sequentially along the light propagation direction: a laser; a beam expander; a beam splitter for splitting the expanded laser beam into two coherent beams; and an interference modulation component for modulating the included angle, spot size, and focusing the two coherent beams, outputting a multi-beam laser composed of multiple interference fringes. This laser interference method has low manufacturing cost and high power utilization, avoiding interference from high diffraction orders caused by diffraction beam splitters and the limitations of diffraction efficiency due to the manufacturing precision constraints of diffraction elements. Furthermore, the laser interference method can achieve 100% uniformity of the multi-beam laser points, while overcoming the manufacturing limitations of multi-beam uniformity in diffraction beam splitting. Additionally, the interference modulation component enables controllable modulation of the multi-beam laser, meeting diverse processing requirements.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a multi-beam laser processing device and system based on laser interference. Background Technology

[0002] Multibeam processing technology has significant necessity and advantages in the wafer fabrication field. Through efforts to improve processing efficiency, enhance processing quality, adapt to complex processing requirements, and reduce equipment costs, multibeam processing technology is expected to bring about a revolutionary change in the wafer fabrication industry.

[0003] Currently, the common method for generating multiple beams is through diffractive optical elements (i.e., diffractive beam splitting elements). This multi-beam processing technology is costly, and the high requirement for beam uniformity further increases the manufacturing difficulty and cost. At the same time, it is limited by diffraction efficiency, resulting in insufficient power utilization, and high diffraction orders can interfere with the processing effect. In addition, the uniformity of multiple beams during diffraction beam splitting is usually not 100% effective, and the uniformity of multiple beams is also subject to manufacturing limitations. Generally, the higher the uniformity requirement, the greater the manufacturing difficulty. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-beam laser processing device and system based on laser interference, so as to at least solve one of the above-mentioned problems.

[0005] In a first aspect, embodiments of the present invention provide a multi-beam laser processing apparatus based on laser interference, comprising the following components arranged sequentially along the direction of light propagation:

[0006] A laser used to emit laser light from a target;

[0007] A beam expander is used to expand the beam of a target laser.

[0008] A beam splitter is used to split the expanded laser beam into two coherent beams and output the expanded laser beam.

[0009] The interference modulation component is used to modulate the included angle, the spot size, and focus two coherent beams to output a multi-beam laser composed of multiple interference fringes.

[0010] Furthermore, the beam splitter includes a first prism, which is configured such that its apex is located at the center of the exit surface, so as to output two symmetrical coherent beams at a certain angle, and the spot size of each coherent beam is half the spot size of the expanded laser beam.

[0011] Furthermore, the incident surface of the first prism is a plane. After beam expansion, the laser beam is incident perpendicularly onto the incident surface of the first prism. The angle between the two coherent beams output by the first prism is... Satisfies the following formula: n×sin Where θ is the angle of the apex at the center of the exit surface in the first prism.

[0012] Furthermore, the interference modulation component includes components arranged along the direction of light propagation:

[0013] Angle modulation assembly for modulating the angle between two coherent beams;

[0014] The first cylindrical lens is used to modulate and focus the size of the interference fringe length direction of the two coherent beams after the angle modulation; the first cylindrical lens is located before the two coherent beams after the angle modulation interfere, and the focal length of the first cylindrical lens in the direction perpendicular to the interference fringe length direction of the beam is 0.

[0015] Furthermore, the included angle modulation assembly includes a first 4F system or a second prism;

[0016] The first 4F system includes a first convex lens and a second convex lens arranged along the direction of light propagation, the distance between the first convex lens and the second convex lens being equal to the sum of the focal lengths of the first convex lens and the second convex lens; the second prism is configured such that its apex is located at the center of the exit surface.

[0017] Furthermore, both the first convex lens and the second convex lens are plano-convex lenses; or, both the first convex lens and the second convex lens are second cylindrical lenses, with the focal length of the second cylindrical lens being 0 in the direction of the interference fringe length of the light spot.

[0018] Furthermore, the apex angle of the second prism is different from that of the first prism.

[0019] Furthermore, the interference modulation component includes components arranged along the direction of light propagation:

[0020] The second 4F system is used to modulate the size of the interference fringe length direction of two coherent beams;

[0021] The third prism is used to modulate and focus the angle between the two coherent beams after size modulation; the third prism is configured such that its apex is located at the center of the exit surface.

[0022] Furthermore, the second 4F system includes a third cylindrical lens and a fourth cylindrical lens arranged along the direction of light propagation;

[0023] The focal lengths of both the third and fourth cylindrical lenses are 0 in the direction perpendicular to the length of the interference fringes, and the distance between the third and fourth cylindrical lenses is equal to the sum of their focal lengths.

[0024] Secondly, embodiments of the present invention also provide a multi-beam laser processing system based on laser interference, including the multi-beam laser processing apparatus based on laser interference as described in the first aspect.

[0025] The multi-beam laser processing apparatus and system based on laser interference provided in this invention includes, in sequence along the light propagation direction: a laser for emitting target laser light; a beam expander for expanding the target laser beam; a beam splitter for splitting the expanded laser beam into two coherent beams; and an interference modulation component for modulating the included angle, the spot size, and focusing the two coherent beams to output a multi-beam laser composed of multiple interference fringes. This multi-beam laser is achieved through laser beam splitting followed by laser interference. Compared to multi-beam processing technology based on diffractive optical elements, it has lower manufacturing costs and higher power utilization. It avoids interference from high diffraction orders caused by diffractive beam splitting elements and the limitations of diffraction efficiency due to the manufacturing precision constraints of diffractive elements. Furthermore, the laser interference method can achieve 100% uniformity of multiple light spots, while overcoming the manufacturing limitations of multi-beam uniformity during diffraction beam splitting. Additionally, the interference modulation component enables controllable modulation of the multi-beam laser, meeting diverse processing requirements. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a multi-beam laser processing system based on laser interference, provided in an embodiment of the present invention.

[0028] Figure 2 A schematic diagram illustrating the beam-splitting principle of an isosceles prism provided in an embodiment of the present invention;

[0029] Figure 3 for Figure 2 Schematic diagram of the interference spot at position 301;

[0030] Figure 4 This is a schematic diagram of the interference spot acting on the processing surface of the sample.

[0031] Figure 5 This is a schematic diagram of another multi-beam laser processing system based on laser interference provided in an embodiment of the present invention.

[0032] Icons: 101-Laser; 102-Beam expander; 103-Reflector; 104-First isosceles prism; 105-First 4F system; 1051-First plano-convex lens; 1052-Second plano-convex lens; 106-Second 4F system; 1061-Third cylindrical lens; 1062-Fourth cylindrical lens; 107-First cylindrical lens; 108-Second isosceles prism; 109-Processed sample; 110-Moving stage; 21-Target laser; 22-Beam after beam expansion; 221-First beam; 222-Second beam; 231-Reduced first beam; 232-Reduced second beam; 241-Focused first beam; 242-Focused second beam; 301-Interference surface; 401-Processed surface. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the field of wafer fabrication, the necessity of multi-beam processing is mainly reflected in the following aspects:

[0035] Improving processing efficiency: Traditional wafer dicing technologies, such as blade cutting or single-focus laser cutting, suffer from slow processing speeds. Multi-beam machining, by using multiple laser beams simultaneously for cutting, can significantly improve wafer processing efficiency. For example, using multi-beam parallel machining, multiple dicing passes can be completed in a single scan, thereby reducing processing time.

[0036] Improving processing quality: Multi-beam processing technology enables more precise control of the laser beam's energy distribution and focal point, resulting in more uniform and precise cuts. This helps reduce the heat-affected zone and slag spatter during the cutting process, improving the quality and yield of wafer dicing.

[0037] Adapting to Complex Processing Needs: With the development of semiconductor technology, wafer processing requirements are becoming increasingly complex. Multi-beam processing technology offers greater flexibility and adaptability, allowing for flexible adjustments to the cutting method based on the characteristics of the dicing paths in the wafer to meet complex processing demands.

[0038] Reduced equipment costs: While multi-beam machining technology may require more complex equipment and optical systems, its high processing efficiency and adaptability to complex processing requirements can reduce production costs in the long run. Furthermore, multi-beam machining technology helps reduce material waste and energy consumption during the production process, further lowering production costs.

[0039] In summary, multi-beam processing technology has significant necessity and advantages in the wafer fabrication field. Existing multi-beam processing technologies based on diffractive optical elements have many drawbacks, such as high cost, high manufacturing difficulty, insufficient power utilization, high diffraction orders interfering with processing results, and the inability to achieve 100% uniformity of the multi-beam points, which is also limited by manufacturing constraints.

[0040] Based on this, the present invention provides a multi-beam laser processing device and system based on laser interference, which adopts a laser interference method based on laser beam splitting in the processing optical path of the multi-beam laser equipment, which can at least solve one of the above-mentioned defects of multi-beam processing technology based on diffractive optical elements.

[0041] To facilitate understanding of this embodiment, a multi-beam laser processing device based on laser interference, as disclosed in this embodiment of the invention, will first be described in detail.

[0042] This invention provides a multi-beam laser processing apparatus based on laser interferometry, the apparatus comprising the following components arranged sequentially along the direction of light propagation:

[0043] A laser used to emit laser light from a target;

[0044] A beam expander is used to expand the beam of a target laser.

[0045] A beam splitter is used to split a laser beam after it has been expanded into two coherent beams.

[0046] The interference modulation component is used to modulate the included angle, the spot size, and focus two coherent beams to output a multi-beam laser composed of multiple interference fringes.

[0047] The aforementioned laser is responsible for emitting the target laser, which typically possesses good coherence and monochromaticity, as well as strong directionality, providing a solid foundation for subsequent beam manipulation and laser interferometry. When selecting a laser, the beam quality factor M of the output laser is preferred. 2 Lasers with values ​​below a preset threshold. This preset threshold can be set according to actual needs and is not limited here; for example, the preset threshold could be 1.3. The laser's M... 2 The closer to 1, the better. The laser described above can be, but is not limited to, an ultraviolet pulsed laser. The ultraviolet pulsed laser can be a picosecond laser or a nanosecond laser. It should be noted that this embodiment does not limit the pulse width of the laser.

[0048] After the target laser beam is emitted from the laser, it first passes through a beam expander. The purpose of the beam expander is to expand the target laser beam, that is, to increase the beam diameter and reduce the beam divergence angle. This process helps to improve the collimation performance of the beam, reduce energy loss caused by beam divergence, and also creates favorable conditions for subsequent beam splitting and interference modulation. By increasing the beam diameter through the beam expander, the spatial length of the subsequent interference fringes (i.e., the length on the interference surface along the direction perpendicular to the length of the interference fringes) and the number of splitting points (the number of splitting points depends on the spatial length of the interference fringes and the spatial period of the interference) can be controlled.

[0049] The laser beam, after being expanded (i.e., the expanded laser), is split into two coherent beams by a beam splitter. A beam splitter is a special optical element that can precisely split the incident light into two beams in a certain proportion while maintaining the coherence of the two beams. This operation provides the necessary prerequisite for subsequent interference phenomena.

[0050] The two coherent beams, after being split, are processed by an interference modulation component. The main function of this component is to modulate the angle between the two beams, the spot size, and focus them, ultimately causing them to meet and interfere at a specific location. By precisely controlling parameters such as the angle between the two beams and the spot size, a multi-beam laser composed of multiple interference fringes can be generated. Specifically, angle modulation controls the spatial period of the interference (i.e., the beam splitting interval), spot size modulation along the length of the interference fringes controls their length, and spot size modulation in the direction perpendicular to the length of the interference fringes controls their spatial length. This multi-beam laser forms a complex intensity distribution pattern in the focal region, enabling precise control and high-quality processing of materials.

[0051] The multi-beam laser processing apparatus based on laser interference provided in this invention realizes multi-beam laser processing by performing laser beam splitting followed by laser interference. Compared with multi-beam processing technology based on diffractive optical elements, it has lower manufacturing costs and higher power utilization. It avoids interference from high diffraction orders caused by diffractive beam splitting elements and the limitation of diffraction efficiency due to the limited manufacturing precision of diffractive elements. Furthermore, the laser interference method can achieve 100% uniformity of multiple light points, while eliminating the manufacturing limitations on the uniformity of multiple light points during diffraction beam splitting. In addition, the controllable modulation of the multi-beam laser is realized through the interference modulation component, which can meet the diversity of processing requirements.

[0052] Optionally, the beam splitter described above can be a first prism or a planar beam splitter. The first prism achieves spatial beam splitting, dividing a beam into two parts, the sum of the spot sizes of these two parts in the splitting direction (i.e., the direction perpendicular to the length of the interference fringes) equals the spot size of the original beam. The planar beam splitter is made of flat glass, with a dielectric beam-splitting film coated on one side and an anti-reflection coating on the other. It is typically designed with a 45° incident angle to achieve beam separation ratios. The planar beam splitter requires appropriate deflection optical paths and beam-combining elements to ensure that both coherent beams enter the interference modulation assembly. The planar beam splitter only separates the energy of the incident light, without changing the spot size; that is, the spatial distribution of the spot remains unchanged, but the energy is halved.

[0053] Preferably, the first prism is configured with its apex located at the center of the exit surface to output two symmetrical coherent beams at a certain angle, with the spot size of each coherent beam being half the spot size of the expanded laser beam. By configuring the first prism with its apex located at the center of the exit surface, the expanded laser beam can be divided into two axially symmetrical parts, facilitating subsequent beam modulation. By changing the angle of the apex at the exit surface of the first prism, the angle between the two output coherent beams can be adjusted, thereby adjusting the beam splitting interval.

[0054] The cross-section of the first prism can be triangular, quadrilateral, or pentagonal, as long as the center of the exit surface is one of its vertices, and the incident surface is a plane or one vertices is located at the center of the incident surface. For example, when the first prism is a triangular prism with a triangular cross-section, the incident surface of the first prism is a plane. After beam expansion, the laser is incident perpendicularly onto the incident surface of the first prism and then exits from the exit surface centered on the vertices. The first prism can be, but is not limited to, an isosceles prism, which refers to a triangular prism with an isosceles triangular cross-section. When the first prism is a quadrilateral prism with a quadrilateral cross-section, the expanded laser is incident with the first vertices as the center and exits with the second vertices as the center. The first and second vertices are two opposite vertices with a certain angular relationship. By changing this angular relationship, the angle between the two output coherent beams can be modulated. When the first prism is a pentagonal prism with a pentagonal cross-section, the expanded laser is incident perpendicularly from one plane of the pentagonal prism and exits with the opposite vertices of that plane as the center.

[0055] Optionally, the incident surface of the first prism is a plane. After beam expansion, the laser beam is incident perpendicularly onto the incident surface of the first prism. At this time, the angle between the two coherent beams output by the first prism is... Satisfy the following formula: Where θ is the angle of the apex at the center of the exit surface in the first prism.

[0056] The embodiments of the present invention provide various implementation methods for the interference modulation component, which are mainly divided into the following two categories:

[0057] I. The interference modulation component includes components arranged along the direction of light propagation:

[0058] Angle modulation assembly for modulating the angle between two coherent beams;

[0059] The first cylindrical lens is used to modulate and focus the size of the interference fringe length direction of the two coherent beams after the angle modulation; the first cylindrical lens is located before the two coherent beams after the angle modulation interfere, and the focal length of the first cylindrical lens in the direction perpendicular to the interference fringe length direction of the beam is 0.

[0060] The aforementioned first cylindrical lens is used to compress the interference fringe length and focus the light to the required processing level. The first cylindrical lens can be a plano-convex circular cylindrical lens, with one side being a plane and the other a cylinder, possessing a positive focal length. Through its special geometry, the first cylindrical lens acts on the light beam only in one direction, thus "compressing" the length of the interference fringes to a certain extent. Specifically, by changing and adjusting the geometry of the first cylindrical lens, the focal length can be changed, thereby controlling the length of the interference fringes and obtaining a spot size that meets the processing requirements. The interference fringe length is shortest when the interference planes of the two beams output by the first cylindrical lens coincide with the focal plane of the first cylindrical lens. The position of the first cylindrical lens can be set according to the required interference fringe length.

[0061] Optionally, the aforementioned angle modulation assembly may include a first 4F system or a second prism; the first 4F system includes a first convex lens and a second convex lens disposed along the direction of light propagation, the distance between the first and second convex lenses being equal to the sum of their focal lengths; the second prism is configured such that its apex is located at the center of the exit surface. The first 4F system can be used to modulate the angle between two coherent beams to adjust the beam splitting interval; it can also modulate the length of the interference fringes by changing the dimensions along the length direction of the interference fringes. The second prism can be used to modulate the angle between two coherent beams to adjust the beam splitting interval.

[0062] In practical implementation, both the first and second convex lenses can be plano-convex lenses to modulate the angle between the two coherent beams and the length of the interference fringes; alternatively, both the first and second convex lenses can be second cylindrical lenses, with a focal length of 0 in the direction of the interference fringe length of the light spot, to modulate the angle between the two coherent beams. The plano-convex lens has one flat surface and the other convex surface, possessing a positive focal length, which can be used to reduce the beam length; the plano-convex lens has a central axis of symmetry, allowing it to affect the beam in two directions. The second cylindrical lens has the same structure as the aforementioned first cylindrical lens, and the second prism has the same structure as the aforementioned first prism, which will not be described again here.

[0063] In order to achieve the modulation of the angle between the two interference beams, the apex angle of the second prism can be different from that of the first prism. The apex angle of the second prism can be greater than that of the first prism. The apex angles of the two can be set according to actual needs, and there is no limitation here.

[0064] II. The interference modulation components include those arranged along the direction of light propagation:

[0065] The second 4F system is used to modulate the size of the interference fringe length direction of two coherent beams;

[0066] The third prism is used to modulate and focus the angle between the two coherent beams after size modulation; the third prism is configured such that its apex is located at the center of the exit surface.

[0067] Optionally, the second 4F system described above may include a third cylindrical lens and a fourth cylindrical lens arranged along the direction of light propagation; the focal length of both the third cylindrical lens and the fourth cylindrical lens is 0 in the direction perpendicular to the length of the interference fringes of the light spot, and the distance between the third cylindrical lens and the fourth cylindrical lens is equal to the sum of the focal lengths of the third cylindrical lens and the fourth cylindrical lens.

[0068] It should be noted that the third and fourth cylindrical lenses mentioned above have the same structure as the first cylindrical lens mentioned above, and the third prism has the same structure as the first prism mentioned above, so they will not be described again here.

[0069] In order to achieve the modulation of the angle between the two interference beams, the apex angle of the third prism can be different from that of the first prism. The apex angles of the two can be set according to actual needs, and there is no limitation here.

[0070] This invention also provides a multi-beam laser processing system based on laser interferometry, including the aforementioned multi-beam laser processing device based on laser interferometry, and may further include a motion stage. The motion stage is used to place the sample to be processed and to move the sample. In this system, the sample is processed by the multi-beam laser output from the device. The processing surface of the sample coincides with the interference surface of the two coherent beams output from the aforementioned interference modulation component. By moving the sample through the motion stage, the processing position can be changed.

[0071] The multi-beam laser processing system based on laser interference provided in this embodiment has the same implementation principle and technical effects as the aforementioned multi-beam laser processing device embodiment based on laser interference. For the sake of brevity, any parts not mentioned in the embodiment of the multi-beam laser processing system based on laser interference can be referred to the corresponding content in the aforementioned embodiment of the multi-beam laser processing device based on laser interference.

[0072] For ease of understanding, the following example uses an isosceles prism as the beam splitter. Figures 1 to 5 This paper provides a detailed introduction to the aforementioned multi-beam laser processing system based on laser interference.

[0073] The aforementioned system includes a multi-beam laser processing optical path based on prism beam splitting interference, employing a prism beam splitting laser interference method, and has the following characteristics:

[0074] 1. Spectroscopic interference is based on ordinary prisms, and its manufacturing difficulty and cost are far lower than those of diffraction spectroscopic devices;

[0075] 2. It is easier to control and achieve the requirements of uniformity and spacing of multiple beam spots in laser processing.

[0076] See Figure 1 The diagram shows a multi-beam laser processing system based on laser interference. The system includes, in sequence along the direction of light propagation: a laser 101, a beam expander 102, a reflector 103, a first isosceles prism 104, a first 4F system 105, a first cylindrical lens 107, and a motion stage 110.

[0077] Specifically, laser 101 is used to provide a light source and emit target laser 21, the spot diameter of target laser 21 being d; laser 101 can be an ultraviolet pulsed laser;

[0078] The beam expander 102 is used to expand the diameter of the outgoing light spot and output the expanded beam 22 to modulate the length of interference (i.e. the length of the laser interference region, hereinafter referred to as the interference length) L; where the beam expansion ratio is k and the diameter of the expanded light spot is D = k × d;

[0079] The reflective component 103 is used to deflect the light path, that is, to change the direction of light propagation;

[0080] The first isosceles prism 104 is used to separate the laser beam, outputting a first beam 221 and a second beam 222; the refractive index of the first isosceles prism 104 is n, and the vertex angle is θ; the beam widths of both the first beam 221 and the second beam 222 are D / 2, according to the law of refraction, The angle between the two can be obtained. (Angle separation only in the Y direction);

[0081] The first 4F system 105 includes: a first plano-convex lens 1051 (focal length f1) and a second plano-convex lens 1052 (focal length f2); the first 4F system 105 is used to modulate the angle δ and interference length L of the two interference beams (first beam 221 and second beam 222), and outputs a reduced first beam 231 and a reduced second beam 232, with a vertical magnification of β = f1 / f2 and an angular magnification of γ = f2 / f1; the distance between the first plano-convex lens 1051 and the second plano-convex lens 1052 is f1 + f2; wherein, the vertical magnification (β) represents the ratio of image height to object height on the conjugate plane, and the angular magnification (γ) is the rate of change of the angle between the light ray emitted from the on-axis point on the conjugate plane and the optical axis after passing through the first 4F system 105; the beam width of both the reduced first beam 231 and the reduced second beam 232 is D / (2β), which is the interference length L, and the interference angle is...

[0082] The first cylindrical lens 107 has a focal length of F and is used to compress the length of the interference fringes. It outputs a focused first beam 241 and a focused second beam 242, both of which are focused to the required processing level. The first cylindrical lens 107 should be installed before the focused first beam 241 and the focused second beam 242 interfere. The focused spot size of the focused first beam 241 and the focused second beam 242 in the X direction is usually 1 to 20 μm, while the interference length and angle in the Y direction remain unchanged.

[0083] The processing surface 401 of the processed sample 109 coincides with the interference surface of the focused first beam 241 and the focused second beam 242;

[0084] The motion stage 110 is used to move the processing sample 109.

[0085] The laser 101 emits target laser 21, which is expanded by beam expander 102 and then split by first isosceles prism 104. The split beam passes through first 4F system 105, which controls the angle between the two beams, thereby controlling the beam splitting interval. At the same time, the beam expansion controls the spatial length of the interference, thereby controlling the number of splitting points and the beam splitting interval. In addition, the length of the interference fringes is controlled by first cylindrical lens 107, thereby obtaining a spot size that meets the processing requirements.

[0086] like Figure 2 As shown, the expanded beam 22 is split into two beams (i.e., the first beam 221 and the second beam 222) by a first isosceles prism 104 (refractive index n, vertex angle θ), with a certain angle between them. (According to the law of refraction, At the point where two beams of light completely overlap and meet, they interfere, producing interference fringes. For example... Figure 3As shown, at the interference plane 301, the length of the light spot in the Y direction is L = D / 2, which is the length at which interference occurs; the length of the light spot in the X direction is L2 = D, which is the length of the interference fringes; and the spatial period of the interference is... This is the beam splitting interval, with the number of splitting points being m = L1 / Λ, which can be considered as m light spots with a length of L2 and a width of Λ. For example... Figure 4 As shown, with Figure 3 In comparison, the length of the interference spot in the X direction is significantly shortened when acting on the processing surface of the sample.

[0087] The system controls the period and spatial length (i.e., the spacing between multiple light spots and the Y-direction dimension) of the interference fringes in the Y direction through the beam expander 102 and the first 4F system 105; and focuses the length (X direction) of the interference fringes through the cylindrical lens to meet the processing requirements.

[0088] See Figure 5 The diagram shows another multi-beam laser processing system based on laser interference. The system includes, in sequence along the direction of light propagation: a laser 101, a beam expander 102, a reflector 103, a first isosceles prism 104, a second 4F system 106, a second isosceles prism 108, and a motion stage 110.

[0089] Specifically, laser 101 is used to provide a light source and emit target laser 21, the spot diameter of target laser 21 being d; laser 101 can be an ultraviolet pulsed laser;

[0090] The beam expander 102 is used to expand the diameter of the outgoing light spot and output the expanded beam 22 to modulate the length of interference (i.e. the length of the laser interference region, hereinafter referred to as the interference length) L; where the beam expansion ratio is k and the diameter of the expanded light spot is D = k × d;

[0091] The reflective component 103 is used to deflect the light path, that is, to change the direction of light propagation;

[0092] The first isosceles prism 104 is used to separate the laser beam, outputting a first beam 221 and a second beam 222; the refractive index of the first isosceles prism 104 is n, and the vertex angle is θ; the beam widths of both the first beam 221 and the second beam 222 are D / 2, according to the law of refraction, The angle between the two can be obtained. (Angle separation only in the Y direction);

[0093] The second 4F system 106 includes a third cylindrical lens 1061 (focal length f1 in the X direction) and a fourth cylindrical lens 1062 (focal length f2 in the X direction). Both have a focal length of 0 in the Y direction and do not have angle adjustment function. The distance between them is f1 + f2. The second 4F system 106 is used to modulate the X-direction width L2 of the two interference beams (first beam 221 and second beam 222) and output a reduced first beam 231 and a reduced second beam 232. The vertical magnification is β = f1 / f2. The beam width of both the reduced first beam 231 and the reduced second beam 232 is D / (2β), which is the length L2 of the interference fringe.

[0094] The apex angle of the second isosceles prism 108 is β (where β < θ), which is used to refocus the first beam 241 and the second beam 242 to interfere, while controlling the interference angle between them. From the law of refraction, we can obtain:

[0095]

[0096] The processing surface 401 of the processed sample 109 coincides with the interference surface of the focused first beam 241 and the focused second beam 242;

[0097] The motion stage 110 is used to move the processing sample 109.

[0098] Laser 101 emits target laser 21, which is expanded by beam expander 102 and then split by first isosceles prism 104. The split beam passes through second 4F system 106, where the length of L2 is controlled. At the same time, the number of splitting points and the splitting interval are controlled by beam expansion control L, thereby generating a spot size that meets the processing requirements.

[0099] The multi-beam laser processing device and system based on laser interferometry provided in this embodiment have the following characteristics:

[0100] Beneficial effects:

[0101] 1. The use of laser beam interferometry to replace diffraction beam splitting reduces manufacturing costs in terms of hardware;

[0102] 2. By using laser interference, 100% uniformity of multiple light spots was achieved, thus overcoming the manufacturing limitations that affect the uniformity of multiple light spots during diffraction spectroscopy.

[0103] 3. By using cylindrical lenses for focusing, the size of the light spot in the X and Y directions can be controlled separately, meeting the diverse processing requirements.

[0104] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0105] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0106] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-beam laser processing device based on laser interference, characterized in that, Including those arranged sequentially along the direction of light propagation: A laser used to emit laser light from a target; A beam expander is used to expand the target laser beam and output the expanded laser beam. A beam splitter is used to split a laser beam after it has been expanded into two coherent beams. An interference modulation component is used to modulate the included angle, the spot size, and focus the two coherent beams to output a multi-beam laser composed of multiple interference fringes. The beam splitter includes a first prism, which is configured such that its apex is located at the center of the exit surface to output two symmetrical coherent beams at a certain angle, and the spot size of each coherent beam is half the spot size of the expanded laser beam.

2. The apparatus according to claim 1, characterized in that, The incident surface of the first prism is a plane. The expanded laser beam is incident perpendicularly onto the incident surface of the first prism. The included angle φ of the two coherent beams output by the first prism satisfies the following formula: n×sin(90°-θ / 2)=sin(90°-θ / 2+φ); where n is the refractive index of the first prism and θ is the angle of the apex at the center of the exit surface of the first prism.

3. The apparatus according to claim 1 or 2, characterized in that, The interference modulation component includes components arranged along the direction of light propagation: An angle modulation assembly is used to modulate the angle between the two coherent beams. A first cylindrical lens is used to modulate and focus the size of the interference fringe length direction of the two coherent beams after the angle modulation; the first cylindrical lens is located before the two coherent beams after the angle modulation interfere, and the focal length of the first cylindrical lens in the direction perpendicular to the interference fringe length direction of the beam is 0.

4. The apparatus according to claim 3, characterized in that, The included angle modulation assembly includes a first 4F system or a second prism; The first 4F system includes a first convex lens and a second convex lens arranged along the direction of light propagation, the distance between the first convex lens and the second convex lens being equal to the sum of the focal lengths of the first convex lens and the second convex lens; the second prism is configured such that its apex is located at the center of the exit surface.

5. The apparatus according to claim 4, characterized in that, Both the first convex lens and the second convex lens are plano-convex lenses; or, both the first convex lens and the second convex lens are second cylindrical lenses, wherein the focal length of the second cylindrical lens is 0 in the direction of the interference fringe length of the light spot.

6. The apparatus according to claim 4, characterized in that, The apex angle of the second prism is different from that of the first prism.

7. The apparatus according to claim 1 or 2, characterized in that, The interference modulation component includes components arranged along the direction of light propagation: The second 4F system is used to modulate the size of the interference fringe length direction of the two coherent beams; A third prism is used to modulate and focus the angle between the two coherent beams after size modulation; the third prism is configured such that its apex is located at the center of the exit surface.

8. The apparatus according to claim 7, characterized in that, The second 4F system includes a third cylindrical lens and a fourth cylindrical lens positioned along the direction of light propagation; Both the third cylindrical lens and the fourth cylindrical lens have a focal length of 0 in the direction perpendicular to the length of the interference fringes, and the distance between the third cylindrical lens and the fourth cylindrical lens is equal to the sum of their focal lengths.

9. A multi-beam laser processing system based on laser interferometry, characterized in that, The multi-beam laser processing apparatus based on laser interference, as described in any one of claims 1-8.

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