Multi-focal laser assembly, laser processing apparatus and method

Abstract

Embodiments of the present application provide a kind of multi-focus laser assembly, laser processing device and method.Multi-focus laser assembly includes laser, beam splitting element, beam angle adjustment assembly, first beam shaping assembly, beam converging assembly and objective lens arranged in order along the direction of light path, laser is used to emit laser beam;Beam splitting element is used to split laser beam into predetermined number of sub-beams;Beam angle adjustment assembly includes predetermined number of sub-adjustment unit, each sub-adjustment unit is used to adjust the transmission angle of corresponding sub-beam;First beam shaping assembly includes predetermined number of sub-beam shaping element, each sub-beam shaping element is used to shape the sub-beam adjusted by corresponding sub-adjustment unit;Beam converging assembly is used to converge all sub-beams with preset optical parameters on objective lens, so that all sub-beams form burst point at predetermined number of positions of object after focusing through objective lens.This scheme has relatively high cutting efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, and more specifically to a multi-focus laser component, a laser processing apparatus, and a laser processing method. Background Technology

[0002] In the field of semiconductor device (e.g., wafer) processing, the dicing process is crucial. There are generally two dicing methods: rotary cutting and laser cutting. Specifically, laser cutting, also known in the industry as stealth cutting, or simply stealth dicing, involves focusing a laser beam inside the object being processed to create an explosion point (or blast point). By precisely controlling the distance between these explosion points, microcracks are formed internally. Then, using a cleaver or vacuum dicing tool, adjacent grains are separated.

[0003] In traditional laser processing equipment, the laser is typically focused onto a single designated location on the object being processed, while the object moves simultaneously. Over time, multiple burn points can be created at different locations along a single cutting path on the object. Because the laser is focused on a single point, traditional laser processing equipment is limited to first cutting all the transverse cutting paths one by one, and then cutting along the longitudinal cutting paths one by one. This cutting method is relatively inefficient. Summary of the Invention

[0004] The present invention was proposed in view of the above-mentioned problems. The present invention provides a multifocal laser component, a laser processing apparatus, and a method.

[0005] According to one aspect of the present invention, a multifocal laser assembly is provided, comprising a laser, a beam splitting element, a beam angle adjustment assembly, a first beam shaping assembly, a beam converging assembly, and an objective lens arranged sequentially along an optical path. The laser emits a laser beam; the beam splitting element splits the laser beam into a predetermined number of beams; the beam angle adjustment assembly includes a predetermined number of sub-adjustment units, each corresponding to a predetermined number of beams, and each sub-adjustment unit adjusts the transmission angle of its corresponding beam; the first beam shaping assembly includes a predetermined number of sub-beam shaping elements, each corresponding to a predetermined number of sub-adjustment units, and each sub-beam shaping element shapes the beam adjusted by its corresponding sub-adjustment unit so that the beam emitted from the corresponding sub-beam shaping element has preset optical parameters; the beam converging assembly converges all beams with preset optical parameters onto the objective lens, such that after being focused by the objective lens, all beams with preset optical parameters form explosion points at a predetermined number of locations on the workpiece, the predetermined number of locations corresponding to a predetermined number of beams.

[0006] For example, the multifocal laser assembly further includes a second beam shaping assembly disposed between the laser and the beam splitting element, for adjusting the optical parameters of the laser beam emitted from the laser so that the adjusted optical parameters meet the incident light requirements of the beam splitting element.

[0007] For example, the multi-focus laser assembly also includes a control unit, which is communicatively connected to the first beam shaping assembly. The control unit is used to adjust the optical parameters of the split beams passing through each sub-beam shaping element to preset optical parameters to adjust the depth of the detonation point corresponding to each split beam inside the workpiece. The optical parameters include the diameter and / or divergence angle of the beam.

[0008] For example, the beam converging assembly is used to adjust the incident angle of each beam entering the objective lens, so that the focused beam forms a burst point on different cutting paths or at different positions on the same cutting path.

[0009] For example, the beam converging assembly includes a first reflector and at least one beam combiner; the first reflector is disposed in the outgoing optical path of the outermost sub-beam shaping element among a predetermined number of sub-beam shaping elements and is used to reflect the corresponding split beam; at least one beam combiner is disposed in the outgoing optical path of the remaining sub-beam shaping elements and is used to reflect the split beam emitted from the corresponding sub-beam shaping element, wherein the first beam combiner adjacent to the first reflector is also used to allow the beam reflected by the first reflector to pass through, each of the remaining beam combiners is also used to allow the beam emitted from the previous beam combiner to pass through, and any beam combiner is used to combine the transmitted light transmitted through the beam combiner and the reflected light reflected by the beam combiner onto the same optical path.

[0010] For example, at least one combining lens has a different transmittance and reflectance ratio.

[0011] For example, the beam converging assembly also includes a second mirror disposed between the last beam combiner and the objective lens for reflecting the beam from the last beam combiner into the objective lens.

[0012] For example, the positions of the first reflector and the second emitter are fixed, and the multifocal laser assembly also includes a control unit for adjusting the position of at least one beam combiner to change the angle between the optical axis of each beam combiner and the optical axis of the second reflector, such that the incident angles of the split beams reflected by the at least one beam combiner on the objective lens are different from each other.

[0013] For example, a predetermined number of beams emitted from the beam splitting element have different energy ratios, the energy ratio being the ratio between the energy of the beam splitting element and the energy of the laser beam.

[0014] For example, the distance between any two adjacent detonation points is equal to the grain spacing of the object being processed.

[0015] According to another aspect of the present invention, a laser processing apparatus is provided, including a stage and the aforementioned multifocal laser assembly, wherein the stage is used to support the object to be processed.

[0016] According to another aspect of the present invention, a laser processing method is provided, comprising: emitting a laser beam toward a workpiece using the aforementioned multi-focus laser assembly to form a set of explosion points at a predetermined number of locations on the workpiece; and controlling the movement of the workpiece to form multiple sets of explosion points on different or identical cutting paths of the workpiece.

[0017] Exemplarily, the method further includes: adjusting the optical parameters of the beams passing through each sub-beam shaping element in the first beam shaping assembly to adjust the depth of the detonation point corresponding to each beam within the workpiece, wherein the optical parameters include the diameter and / or divergence angle of the beam; and / or adjusting the incident angle of each beam entering the objective lens through the beam converging assembly, such that the focused beam forms detonation points on different cutting paths or at different positions on the same cutting path.

[0018] According to the multifocal laser assembly, laser processing apparatus, and method of the present invention, a laser beam is split into different beams, and each beam is then shaped and focused separately, so that after being focused by an objective lens, each beam can form a bomb at a predetermined number of locations on the object being processed. This method can simultaneously form modified bombs at different locations inside the object being processed, rather than being limited to a single bomb at a single location. Therefore, this method has higher cutting efficiency. Attached Figure Description

[0019] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of the embodiments of the invention in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same parts or steps.

[0020] Figure 1 A schematic block diagram of a multifocal laser assembly according to an embodiment of the present invention is shown;

[0021] Figure 2A schematic diagram showing the formation of blast points at different depths within the same cutting path of a workpiece according to an embodiment of the present invention is provided.

[0022] Figure 3 A schematic diagram showing multiple explosion points formed at different locations of a cutting path parallel to the material movement direction, according to an embodiment of the present invention, is provided.

[0023] Figure 4 A schematic diagram illustrating the formation of multiple explosion points at corresponding positions on different cutting paths parallel to the material movement direction, according to another embodiment of the present invention; and

[0024] Figure 5 A schematic flowchart of a laser processing method according to an embodiment of the present invention is shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of the present invention.

[0026] To at least partially solve the above problems, according to an embodiment of the present invention, a multi-focus laser assembly is provided.

[0027] Figure 1 A schematic block diagram of a multifocal laser assembly 1000 according to an embodiment of the present invention is shown. Figure 1 As shown, the multifocal laser assembly 1000 may include a laser 1100, a beam splitter 1200, a beam angle adjustment assembly 1300, a first beam shaping assembly 1400, a beam converging assembly 1500, and an objective lens 1600 arranged sequentially along the optical path. It should be noted that... Figure 1 The structure of the multifocal laser assembly 1000 and the arrangement of its components shown are merely examples and not limitations of the invention. The multifocal laser assembly according to embodiments of the invention is not limited to... Figure 1 The specific form shown. For example, Figure 1 A second beam shaping assembly 1700 is shown. This assembly is optional, and can also be configured with appropriate components and parameter settings to allow the laser beam emitted by the laser 1100 to directly enter the beam splitter 1200, thus eliminating the need for the second beam shaping assembly 1700. For example, Figure 1The beam converging assembly 1500 shown includes two mirrors and at least one beam combiner, but the type and arrangement of the mirrors included in the beam converging assembly 1500 can be changed.

[0028] Laser 1100 is used to emit a laser beam.

[0029] Optionally, the wavelength of laser 1100 is selected to be able to penetrate into the material of the object being processed. For example, laser 1100 may be a picosecond laser.

[0030] The beam splitter 1200 is used to split a laser beam into a predetermined number of beams.

[0031] In this embodiment, the predetermined number N ≥ 1. Preferably, N ≥ 2. The laser beam emitted by the laser 1100 can be split into one or more beams using the beam splitting element 1200. When there are multiple beams, any two beams can have the same or different power. The beam splitting element 1200 can be implemented using any existing or future laser beam splitter.

[0032] The beam angle adjustment assembly 1300 may include a predetermined number of sub-adjustment units, each of which corresponds to a predetermined number of beams, and each sub-adjustment unit is used to adjust the transmission angle of the corresponding beam.

[0033] like Figure 1 As shown, the beam angle adjustment assembly 1300 may include a predetermined number of sub-adjustment units 1301, 1302, 1303, ..., 130N. The beam angle adjustment assembly 1300 can be used to adjust the angles of each beam segment emitted from the beam splitting element 1200, thereby enabling each beam segment to enter the first beam shaping assembly 1400 at a predetermined angle for adjustment of the beam's optical parameters (such as diameter and / or divergence angle). Exemplarily, and not limitingly, the beam segments adjusted by the beam angle adjustment assembly 1300 may be parallel to each other. Exemplarily, each sub-adjustment unit in the beam angle adjustment assembly 1300 may be a reflective mirror suitable for a target wavelength band, to cooperate in adjusting each beam segment into a parallel beam. Here, the target wavelength band refers to the laser beam band used by the system, such as infrared 1000nm-1600nm, green light 500nm-550nm, or ultraviolet 250nm-360nm, etc. Each sub-adjustment unit in the beam angle adjustment assembly 1300 may employ a coating layer suitable for the target wavelength band to facilitate the reflection of the split beam.

[0034] The first beam shaping assembly 1400 may include a predetermined number of sub-beam shaping elements, each of which corresponds to a predetermined number of sub-adjustment units. Each sub-beam shaping element is used to shape the split beam adjusted by the corresponding sub-adjustment unit so that the split beam emitted from the corresponding sub-beam shaping element has preset optical parameters.

[0035] The preset optical parameters can be set to any suitable parameters as needed, and this invention does not limit this. The preset optical parameters corresponding to any two sub-beam shaping elements can be the same or different.

[0036] For example, each sub-beam shaping element in the first beam shaping assembly 1400 can be a beam expander. For example, each sub-beam shaping element in the first beam shaping assembly 1400 can be a motorized beam expander, which facilitates automatic adjustment of the optical parameters corresponding to each sub-beam shaping element via a control unit. Of course, each sub-beam shaping element in the first beam shaping assembly 1400 can also be a manually controlled beam expander, allowing the user to manually adjust the optical parameters corresponding to each sub-beam shaping element. The first beam shaping assembly 1400 may include sub-beam shaping elements 1401, 1402, 1403, ..., 140N, with a predetermined number of sub-beam shaping elements corresponding one-to-one with the aforementioned predetermined number of sub-adjustment units 1301, 1302, 1303, ..., 130N. By adjusting the optical parameters corresponding to each sub-beam shaping element, such as the beam diameter and divergence angle, the focusing depth of each beam can be adjusted. When the optical parameters are the same, the focusing depth of the beam is also the same; conversely, when the optical parameters are different, the focusing depth of the beam is also different.

[0037] The beam converging assembly 1500 is used to converge all the beams with preset optical parameters onto the objective lens 1600, so that after all the beams with preset optical parameters are focused by the objective lens 1600, they form explosion points at a predetermined number of positions on the object being processed, and the predetermined number of positions corresponds one-to-one with the predetermined number of beams.

[0038] In one embodiment, the beam converging assembly 1500 and the objective lens 1600 are arranged sequentially. Exemplarily, and not limitingly, the beam converging assembly 1500 may include at least two mirrors and at least one beam combiner. Exemplarily, the objective lens 1600 may be a compound lens group objective lens. Furthermore, exemplarily, the magnification of the objective lens 1600 is ≥10.

[0039] In one example, any two different beams of light, after being focused by objective lens 1600, can form explosion points at different depths of the workpiece. In another example, any two different beams of light, after being focused by objective lens 1600, can form explosion points on different cutting paths of the workpiece. In yet another example, any two different beams of light, after being focused by objective lens 1600, can form explosion points at different locations on the same cutting path of the workpiece. In the latter two examples, the explosion points corresponding to any two different beams of light can be at the same depth or at different depths of the workpiece. The methods for forming explosion points in the above examples will be described in the embodiments below.

[0040] Since the above-mentioned solution is a non-contact laser processing method, it has the advantages of no contact contamination and no mechanical deformation to the processed object. In addition, because the above-mentioned solution uses laser internal focusing modification technology, the modification area can be controlled within 10μm, resulting in almost no material loss. For example, in the design of wafer chip aisles, the size can be minimized, thus also saving material costs.

[0041] According to an embodiment of the multifocal laser assembly of the present invention, the laser beam is split into different beams, and each beam is then shaped and focused separately, so that after being focused by the objective lens, the beams can form explosion points at a predetermined number of locations on the workpiece. This method can simultaneously form modified explosion points at different locations inside the workpiece, rather than being limited to a single explosion point at a single location. Therefore, this method has higher cutting efficiency.

[0042] For example, the multifocal laser assembly 1000 may further include a second beam shaping assembly 1700 disposed between the laser 1100 and the beam splitter 1200 for adjusting the optical parameters of the laser beam emitted from the laser 1100, such that the adjusted optical parameters meet the incident light requirements of the beam splitter 1200.

[0043] like Figure 1As shown, the multifocal laser assembly 1000 may further include a second beam shaping assembly 1700. In one embodiment, the second beam shaping assembly 1700 may be disposed between the laser 1100 and the beam splitter 1200. Exemplarily and not limitingly, the second beam shaping assembly 1700 may include a reflector 1710, a beam expander 1720, a reflector 1730, and a focusing lens 1740. It is understood that the reflector 1710 and / or the reflector 1730 may be omitted. For example, the outgoing light path of the laser 1100 may coincide with the incoming light path of the beam expander 1720, in which case it is not necessary to use the reflector 1710 to reflect the laser beam emitted by the laser 1100. The beam emitted by the laser 1100 is adjusted by the second beam shaping assembly 1700 to adjust the diameter and divergence angle of the beam to meet the incident light requirements of the beam splitter 1200. For example, the aforementioned incident requirement could refer to a beam diameter of 6 mm and an incident angle perpendicular to the center of the beam splitter element 120°. Optionally, the diameter and divergence angle of the laser beam can be automatically adjusted by the control unit, or they can be manually adjusted according to the user's needs.

[0044] The second beam shaping component can adjust the laser beam emitted by the laser to a beam that meets the incident light requirements of the beam splitting element. This facilitates the adaptation to various lasers and helps to improve the application range of multi-focus laser components.

[0045] For example, the beam converging assembly 1500 may include a first reflector and at least one beam combiner; the first reflector is disposed in the outgoing optical path of the outermost sub-beam shaping element among a predetermined number of sub-beam shaping elements and is used to reflect the corresponding split beam; at least one beam combiner is disposed in the outgoing optical path of the remaining sub-beam shaping elements and is used to reflect the split beam emitted from the corresponding sub-beam shaping element, wherein the first beam combiner adjacent to the first reflector is also used to allow the beam reflected by the first reflector to pass through, each of the remaining beam combiners is also used to allow the beam emitted from the previous beam combiner to pass through, and any beam combiner is used to combine the transmitted light transmitted through the beam combiner and the reflected light reflected by the beam combiner onto the same optical path.

[0046] Refer again Figure 1The beam converging assembly 1500 may include a first reflecting mirror 1510 and beam combiners 1521, 1522, 1523, ..., 152M, where M = N-1. The first reflecting mirror 1510 is disposed in the outgoing light path of the sub-beam shaping element 1401. The first reflecting mirror 1510 reflects the light emitted from the sub-beam shaping element 1401 onto the beam combiner 1521 adjacent to the first reflecting mirror 1510. The beam combiners 1521, 1522, 1523, ..., 152M reflect the light emitted from the sub-beam shaping elements 1402, 1403, 1404, ..., 140N, respectively. Furthermore, each beam combiner allows the light beam emitted from the preceding beam combiner to pass through. For example, beam combiner 1521 can transmit the light beam reflected by the first reflecting mirror 1510, while the other beam combiners 1522, 1523, ..., 152M can transmit the light beam emitted from the previous beam combiner. Each beam combiner can combine the corresponding transmitted and reflected light onto the same optical path for emission.

[0047] In the above technical solution, the combination of the first reflecting mirror and the beam combiner can converge the split beams from each sub-beam shaping element onto the same optical path, so as to facilitate further convergence of these beams onto the subsequent objective lens.

[0048] For example, the beam converging assembly 1500 may also include a second mirror 1530 disposed between the last beam combiner and the objective lens 1600 for reflecting the beam from the last beam combiner into the objective lens 1600.

[0049] like Figure 1 As shown, the second reflecting mirror 1530 is positioned between the beam combiner 152M and the objective lens 1600, reflecting the light beam from the beam combiner 152M into the objective lens 1600. The angle of the reflected light beam entering the objective lens 1600 can be adjusted by adjusting the angle of the second reflecting mirror 1530. The second reflecting mirror 1530 is optional. For example, the objective lens 1600 can be directly positioned in the output light path of the beam combiner 152M, in which case the second reflecting mirror 1530 is unnecessary.

[0050] In the above technical solution, the second reflecting mirror can reflect the light beam from the last beam combiner into the objective lens. Thus, the angle at which the light beam is reflected into the objective lens can be flexibly adjusted to meet different cutting requirements for the object being processed.

[0051] For example, the multi-focus laser assembly 1000 may also include a control unit (not shown) communicatively connected to the first beam shaping assembly 1400. The control unit is used to adjust the optical parameters of the split beams passing through each sub-beam shaping element to preset optical parameters to adjust the depth of the detonation point corresponding to each split beam inside the workpiece. The optical parameters include the diameter and / or divergence angle of the beam.

[0052] For example, the control unit can be constructed using electronic components such as comparators, registers, and digital logic circuits, or implemented using processor chips such as microcontrollers, microprocessors, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic arrays (PLAs), and application-specific integrated circuits (ASICs) and their peripheral circuits. For example, the control unit may include one or a combination of several of the following: a central processing unit (CPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), or other processing units with data processing capabilities and / or instruction execution capabilities.

[0053] The control unit and the first beam shaping assembly 1400 can be connected and communicate via any existing or future wired or wireless connection method. The sub-beam shaping elements 1401, 1402, 1403, ..., 140N can be motor-driven beam shaping elements, such as motorized beam expanders. The motor in the sub-beam shaping element can drive the lens group therein to change the magnification, thereby adjusting the optical parameters of each beam emitted by the sub-beam shaping element, such as the beam diameter and divergence angle, and further adjusting the depth of the detonation point corresponding to each beam within the workpiece.

[0054] In the first embodiment, the object being processed is a silicon carbide wafer. The laser 1100 is selected as an infrared picosecond laser. The laser beam is adjusted to a diameter of 6 mm by the second beam shaping assembly 1700 and enters perpendicularly into the beam splitter 1200, which is custom-designed with five light points, splitting the laser beam into five beams (i.e., the split beams described herein). The angles of the mirrors in the beam angle adjustment assembly 1300 are adjusted to make the five split beams parallel, and each beam enters perpendicularly into one of the five sub-beam shaping elements in the first beam shaping assembly 1400. In each sub-beam shaping element 1401, 1402, 1403, 1404, and 1405, the optical parameters of the five split beams are adjusted to different optical parameters. Subsequently, the five beams are converged together by the first reflecting mirror 1510 and the four beam combining mirrors 1521, 1522, 1523 and 1524 in the beam converging assembly 1500, and the five beams are focused into the material by the objective lens 1600 through the second reflecting mirror 1530 in the beam converging assembly 1500. Figure 2 A schematic diagram illustrating the formation of blast points at different depths within the same cutting path of a workpiece according to an embodiment of the present invention is shown. Figure 2 As shown, the depth of the laser focusing point within the vertical section of the silicon carbide wafer can be adjusted by changing the diameter and divergence angle of each beam emitted from the first beam shaping component 1400, thus forming modified points of different depths. Furthermore, a high-speed, precision motion system drives the wafer to move, causing the material to form modified layers of varying depths within it. This, combined with mechanical dicing and film expansion, completes the grain cutting and separation, improving wafer cutting efficiency.

[0055] By adjusting the optical parameters of the beams passing through each sub-beam shaping element using a control unit, the depth of the detonation point corresponding to each beam within the workpiece can be adjusted to meet the required cutting depth. This scheme, which uses a control unit to control the optical path system, allows for flexible modification of the spatial position of the focal point within the material, enabling the cutting of materials of varying thicknesses and chips of different sizes.

[0056] For example, the beam converging assembly 1500 is used to adjust the incident angle of each beam entering the objective lens 1600, so that the focused beam forms a burst point on different cutting paths or at different positions on the same cutting path.

[0057] In the second embodiment, the object being processed is a micro LED (Mico LED) wafer. The laser 1100 can be an infrared picosecond laser. The laser beam is adjusted to a diameter of 6 mm by the second beam shaping assembly 1700 and enters perpendicularly into the beam splitter element 1200, which is custom-designed with five light points, splitting the laser beam into five beams. The angles of the mirrors in the beam angle adjustment assembly 1300 are adjusted to make the five beams parallel, and each beam enters perpendicularly into one of the five sub-beam shaping elements in the first beam shaping assembly 1400. In each sub-beam shaping element 1401, 1402, 1403, 1404, and 1405, the optical parameters of the five beams are adjusted to have the same diameter and divergence angle. The beam converging assembly 1500 converges the five beams into approximately the same direction. For example, the five beams can be arranged so that their corresponding outgoing light paths in the beam converging assembly 1500 form a small angle with each other, and then, with the help of the second reflector 1530, the five beams are converged to different positions on the objective lens 1600. Through the objective lens 1600, each beam is focused into the interior of the material, and the focused point is at a consistent depth within the material, but the focused points for different beams are located on different cleavage paths or at different positions within the same cleavage path. For example, by finely adjusting the angle between the first reflector 1510, at least one beam combiner lens 1521, 1522, ..., 152M, and the second reflector 1530, the five beams can be made perpendicular to the material cutting direction, simultaneously cutting five cleavage paths. Combined with a high-speed, precision motion system to move the wafer, a modified layer of the same depth is formed inside the material. Then, mechanical dicing and film expansion complete the grain cutting and separation, improving wafer cutting efficiency.

[0058] Figure 3 The diagram illustrates the formation of multiple explosion points at different locations along a cutting path parallel to the material movement direction, according to an embodiment of the present invention. Figure 4 A schematic diagram illustrating the formation of multiple explosion points at corresponding positions on different cutting paths parallel to the material movement direction, according to another embodiment of the present invention, is shown. Figure 3 and Figure 4 As shown, after each beam passes through the objective lens 1600, it can form explosion points at the same depth on the same or different cutting paths of the workpiece. Preferably, the spacing between the explosion points can be equal.

[0059] According to the above technical solution, simultaneously cutting different cutting paths or different positions of the same cutting path on the workpiece can effectively improve the cutting efficiency of the workpiece.

[0060] For example, at least one combining lens has a different transmittance and reflectance ratio.

[0061] Any two lenses in at least one combining lens may have the same transmittance to reflectance ratio, or they may have different transmittance to reflectance ratios, which can be set according to user needs. For example, the transmittance to reflectance ratio of any combining lens may be 50:50.

[0062] At least one beam combiner has a different transmittance and reflectance ratio, so that the focusing energy of the split beam corresponding to different beam combiners is different, which can be adapted to various laser processing application scenarios.

[0063] For example, the positions of the first reflector 1510 and the second emitter 1530 are fixed. The multifocal laser assembly 1000 also includes a control unit for adjusting the position of at least one beam combiner to change the angle between the optical axis of each beam combiner and the optical axis of the second reflector 1530, such that the incident angles of the split beams reflected by the at least one beam combiner on the objective lens 1600 are different from each other.

[0064] Optionally, the optical path transmitted along the sub-beam shaping element 1401, the first reflecting mirror 1510, and the second reflecting mirror 1530 can be a fixed optical path, that is, the positions of the first reflecting mirror 1510 and the second reflecting mirror 1530 are fixed. In this case, the angle between the optical axis of each beam combiner and the optical axis of the second reflecting mirror 1530 can be changed by adjusting the positions of the beam combiners 1521, 1522, 1523, ..., 152M, thereby making the incident angles of the split beams reflected by the beam combiners 1521, 1522, 1523, ..., 152M on the objective lens 1600 different from each other.

[0065] For example, any one of the at least one beam combiner lenses can be a planar lens or a cubic lens. When the beam combiner lens is a planar lens, the incident and outgoing rays of the planar lens will be offset, i.e., not on the same straight line (while the incident and outgoing rays of the cubic lens are on the same straight line). Therefore, the position of the beam combiner lens in the first direction will be adjusted according to the actual situation, i.e., the beam combiner lens will be translated in the first direction. Here, the first direction refers to the direction of the outgoing light path of the sub-beam shaping element corresponding to the beam combiner lens (i.e.,...). Figure 1 (as shown in the vertical direction). When the beam combiner is a flat lens, adjusting the position of the beam combiner in the first direction can also change the incident angle of the beam splitter reflected by the beam combiner on the objective lens 1600.

[0066] In summary, the control unit can be used to adjust the position of at least one beam combiner to change the angle between the optical axis of one or more of the beam combiners and the optical axis of the second reflector 1530 and / or change the position of one or more of the beam combiners in the first direction, such that the incident angles of the beams reflected by at least one beam combiner on the objective lens 1600 are different from each other.

[0067] For example, a predetermined number of beams emitted from the beam splitting element 1200 have different energy ratios, the energy ratio being the ratio between the energy of the beam splitting element and the energy of the laser beam.

[0068] The ability of split beams to have different energy ratios facilitates the application of multifocal laser components to specific laser processing scenarios, such as those where material properties differ at different depths and require varying focusing energies. Optionally, any two split beams can have the same energy ratio or different energy ratios, which can be set as needed. In one example, the energy of a predetermined number of split beams can be set evenly. For example, assuming there are five split beams in total, the energy of each split beam can each account for one-fifth of the energy of the laser beam.

[0069] For example, the distance between any two adjacent detonation points is equal to the grain spacing of the object being processed.

[0070] For example, the distance between any two adjacent detonation points is equal to the grain spacing of the workpiece and is <50μm. This allows for the cutting of the intermediate regions of different channels, thereby avoiding cutting the grains and protecting the workpiece.

[0071] According to another aspect of the present invention, a laser processing apparatus is also provided. This laser processing apparatus may include a stage and a multifocal laser assembly as described above, wherein the stage is used to support the object to be processed.

[0072] For example, the object being processed can be a wafer. The wafer is placed on a stage, and as the stage moves, the wafer can be moved, which facilitates the formation of a modified layer inside the material.

[0073] According to another aspect of the present invention, a laser processing method is also provided. Figure 5 A schematic flowchart of a laser processing method 500 according to an embodiment of the present invention is shown, such as... Figure 5 As shown, the laser processing method 500 may include the following steps.

[0074] Step S510: A laser beam is emitted toward the workpiece using the multi-focus laser assembly described above, so as to form a set of explosion points at a predetermined number of locations on the workpiece.

[0075] For example, the above-described implementation of using a multi-focus laser assembly to emit a laser beam toward a workpiece to form a set of explosion points at a predetermined number of locations on the workpiece has been described in detail, and will not be repeated here for the sake of brevity.

[0076] Step S520: Control the movement of the workpiece to form multiple sets of explosion points on different or the same cutting paths of the workpiece.

[0077] For example, the workpiece can be moved by a moving platform, thereby forming multiple sets of explosion points on different or the same cutting paths of the workpiece.

[0078] In the above technical solution, a set of explosion points can be formed at the same time using a multi-focus laser component. Combined with the movement of the object being processed, multiple sets of explosion points can be quickly formed inside the object being processed, which can greatly improve the cutting efficiency.

[0079] For example, the laser processing method 500 may further include: adjusting the optical parameters of the split beams passing through each sub-beam shaping element in the first beam shaping assembly to adjust the depth of the detonation point corresponding to each split beam inside the object being processed, wherein the optical parameters include the diameter and / or divergence angle of the beam; and / or adjusting the incident angle of each split beam entering the objective lens through the beam converging assembly, so that the focused beam forms detonation points on different cutting paths or at different positions on the same cutting path.

[0080] Those skilled in the art can understand the implementation of the above two methods by reading the above descriptions regarding adjusting the optical parameters of the beams passing through each sub-beam shaping element in the first beam shaping assembly to adjust the depth of the explosion point corresponding to each beam inside the workpiece, and adjusting the incident angle of each beam entering the objective lens through the beam converging assembly so that the focused beam forms explosion points on different cutting paths or at different positions on the same cutting path. For the sake of brevity, these descriptions will not be repeated here.

[0081] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of the invention thereto. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as claimed in the appended claims.

[0082] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0083] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0084] The above description is merely a specific embodiment of the present invention or an explanation of that embodiment. The scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-focal laser assembly, comprising: The components include a laser, a beam splitter, a beam angle adjustment assembly, a first beam shaping assembly, a beam converging assembly, and an objective lens, arranged sequentially along the optical path. The laser is used to emit a laser beam; The beam splitter is used to split the laser beam into a predetermined number of beams; The beam angle adjustment component includes a predetermined number of sub-adjustment units, each of which corresponds to a predetermined number of beam splitters. Each sub-adjustment unit is used to adjust the transmission angle of the corresponding beam splitter. The first beam shaping assembly includes a predetermined number of sub-beam shaping elements, each of which corresponds to a predetermined number of sub-adjustment units. Each sub-beam shaping element is used to shape the split beam adjusted by the corresponding sub-adjustment unit so that the split beam emitted from the corresponding sub-beam shaping element has preset optical parameters. The beam converging assembly is used to converge all the beams with the preset optical parameters onto the objective lens, so that after being focused by the objective lens, all the beams with the preset optical parameters form explosion points at a predetermined number of positions on the workpiece. The predetermined number of positions corresponds one-to-one with the predetermined number of beams. The beam converging assembly is also used to adjust the incident angle of each beam entering the objective lens, so that the focused beam forms explosion points at different positions on different cutting paths. The beam converging assembly includes at least one beam combiner and a second reflector. The second reflector is disposed between the last beam combiner and the objective lens, and is used to reflect the beam from the last beam combiner into the objective lens. The multifocal laser assembly also includes a control unit, which is used to adjust the position of the at least one beam combiner to change the angle between the optical axis of each beam combiner and the optical axis of the second reflector, so that the incident angles of the beams reflected by the at least one beam combiner on the objective lens are different from each other.

2. The multifocal laser assembly according to claim 1, characterized in that, The multifocal laser assembly also includes a second beam shaping assembly. The second beam shaping component is disposed between the laser and the beam splitting element, and is used to adjust the optical parameters of the laser beam emitted from the laser so that the adjusted optical parameters meet the incident light requirements of the beam splitting element.

3. The multifocal laser assembly according to claim 1 or 2, characterized in that, The control unit is communicatively connected to the first beam shaping component. The control unit is used to adjust the optical parameters of the split beams passing through each sub-beam shaping element to the preset optical parameters, so as to adjust the depth of the explosion point corresponding to each split beam inside the workpiece. The optical parameters include the diameter and / or divergence angle of the beam.

4. The multi-focal laser assembly of claim 1, wherein, The beam converging assembly includes a first reflector; The first reflector is disposed on the outgoing optical path of the outermost sub-beam shaping element among the predetermined number of sub-beam shaping elements and is used to reflect the corresponding split beam; The at least one beam combiner is disposed in a corresponding manner on the outgoing optical path of the remaining sub-beam shaping element and is used to reflect the split beam emitted from the corresponding sub-beam shaping element. The first beam combiner adjacent to the first reflector is also used to allow the beam reflected by the first reflector to pass through. Each of the remaining beam combiners is also used to allow the beam emitted from the previous beam combiner to pass through. Any beam combiner is used to combine the transmitted light transmitted through the beam combiner and the reflected light reflected by the beam combiner into the same optical path.

5. The multi-focal laser assembly of claim 4, wherein, The at least one combining lens has a different transmittance and reflectance ratio.

6. The multi-focal laser assembly of claim 4, wherein, The positions of the first reflector and the second reflector are fixed.

7. The multifocal laser assembly according to claim 1 or 2, characterized in that, The predetermined number of beams emitted from the beam splitting element have different energy ratios, the energy ratio being the ratio between the energy of the beam splitting element and the energy of the laser beam.

8. The multifocal laser assembly according to claim 1 or 2, characterized in that, The distance between any two adjacent detonation points is equal to the grain spacing of the processed object.

9. A laser processing apparatus characterized by comprising: It includes a stage and a multifocal laser assembly as described in any one of claims 1 to 8, wherein the stage is used to support the object being processed.

10. A laser processing method characterized by, include: A laser beam is emitted toward the workpiece using a multifocal laser assembly as described in any one of claims 1 to 8 to form a set of explosion points at a predetermined number of locations on the workpiece. The workpiece is controlled to move so as to form multiple sets of explosion points on different cutting paths of the workpiece.

11. The laser processing method according to claim 10, characterized by, The method further includes: The optical parameters of the beam splitters passing through each sub-beam shaping element in the first beam shaping assembly are adjusted to adjust the depth of the detonation point corresponding to each beam splitter within the workpiece, wherein the optical parameters include the beam diameter and / or divergence angle; and / or Adjust the incident angle of each beam that enters the objective lens after passing through the beam converging assembly, so that the focused beam forms a burst point at different positions on different cutting paths.

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