Wafer multi-light-spot cutting system and wafer multi-light-spot cutting method

Abstract

The wafer multi-light-spot cutting system comprises a mixed light emitter, a light splitting assembly, a light combining assembly and a beam expanding assembly, mixed light beams emitted by the mixed light emitter at least comprise two kinds of light beams with different wavelengths, and the light splitting assembly can split the mixed light beams into 2n sub light beams, the 2n sub light beams can enter the beam expanding assembly, the beam expanding assembly can adjust the focuses of different light beams, and the 2n sub light beams can be combined into a cutting light beam with at least two focuses in the vertical direction after entering the light combining assembly. The invention further discloses a wafer multi-light-spot cutting method, the wafer is cut through the wafer multi-light-spot cutting system, multi-light-spot cutting can be carried out, light loss is small, longitudinal cutting is even, perpendicularity is high, the heat effect and stress concentration can be reduced, and therefore the yield is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer processing, and in particular to a wafer multi-light spot cutting system and a wafer multi-light spot cutting method. Background Art

[0002] With the rapid development of the LED industry, the size of wafers is getting smaller and smaller, and the verticality of the cutting surface of the wafer is required to be higher and higher, that is, the requirements for cutting accuracy are increasing. There are laser cutting methods for cutting wafers. Among them, the traditional laser cutting method usually adopts a single light spot cutting method. The single light spot method uses a single laser light spot for cutting. When cutting, the single light spot can be focused into a very small light spot, and its minimum diameter can be less than 0.1mm, so that the focus can reach a very high power density. However, due to the high power density and the relatively single cutting position, when processing thicker wafers, this concentrated energy release is difficult to ensure the consistency and verticality of the cutting surface within the entire depth range, which can easily lead to the tilt of the cutting surface, increased surface roughness, edge collapse or cracks, etc. In some extreme cases, the energy cannot effectively penetrate the entire material thickness and cannot be cut at all. In addition, due to the excessive energy, it is easy to cause thermal effects and stress concentration problems. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a wafer multi-light spot cutting system that can perform multi-point cutting with less light loss and uniform cutting, and can also reduce thermal effects and stress concentration, thereby improving yield.

[0004] In order to solve the above technical problems, the present invention provides a wafer multi-light-spot cutting system, comprising a mixed light transmitter with at least two wavelength outputs, a beam splitter component, a beam expansion component and a light combining component, wherein the mixed light beam emitted by the mixed light transmitter comprises at least two light beams with different wavelengths, the beam splitter component can split the mixed light beam into 2n sub-beams, and the 2n sub-beams can adjust the focus of different light beams through the beam expansion component.

[0005] After entering the light combining component, the 2n sub-beams can be combined into a cutting light beam having at least two focal points in the same straight line direction; wherein n>0.

[0006] As an improvement of the above solution, the light splitting component includes a first light splitting element, a part of the mixed light emitted by the mixed light emitter is reflected in the first light splitting element to form a first light beam, and another part passes through the first light splitting element to form a second light beam.

[0007] As an improvement of the above-mentioned scheme, the beam expanding assembly includes a first beam expanding mirror, which is located on the exit light path of the first light beam and / or the second light beam. The light combining assembly includes a first light combining component, which is arranged on the exit light path of the first beam expanding mirror. The first light beam and the second light beam can be combined into the cutting beam by passing through the first light combining component.

[0008] As an improvement of the above solution, the beam splitter assembly further includes a second beam splitter and / or a third beam splitter, a portion of the first light beam passes through the second beam splitter to form a third light beam, and another portion is reflected by the second beam splitter to form a fourth light beam.

[0009] The light splitting component further includes a third light splitting element, a portion of the second light beam is reflected by the third light splitting element to form a fifth light beam, and another portion of the second light beam passes through the third light splitting element to form a sixth light beam.

[0010] As an improvement of the above solution, the second beam splitter and the third beam splitter are both semi-reflective and semi-mirror elements.

[0011] As an improvement of the above-mentioned scheme, the light combining assembly also includes a second light combining component, a third light combining component and a fourth light combining component. The third light beam and the fifth light beam form a first combined light beam in the second light combining component, the fourth light beam and the sixth light beam form a second combined light beam in the third light combining component, and the first combined light beam and the second combined light beam form the cutting beam in the fourth light combining component.

[0012] As an improvement of the above-mentioned scheme, the second light combining component and the third light combining component are both dichroic mirrors, the outgoing light path of the third light beam after reflection by the second light combining component coincides with the outgoing light path of the fifth light beam after passing through the second light combining component, and the outgoing light path of the fourth light beam after reflection by the third light combining component coincides with the outgoing light path of the sixth light beam after passing through the third light combining component.

[0013] The fourth light combining component is a polarization beam splitter prism, and an outgoing light path of the first combined light beam after being reflected by the fourth light combining component coincides with an outgoing light path of the second combined light beam after passing through the fourth light combining component.

[0014] As an improvement of the above solution, the beam expanding assembly also includes a second beam expanding mirror, which is respectively located on the exit light paths of at least three light beams among the third light beam, the fourth light beam, the fifth light beam and the sixth light beam.

[0015] As an improvement of the above scheme, the wafer multi-light-spot cutting system also includes a half-wave plate, which is respectively arranged on the exit light paths of the third light beam, the fourth light beam, the fifth light beam, the sixth light beam and the cutting beam.

[0016] As an improvement of the above-mentioned scheme, a reflector is provided at the turning point of the outgoing light path of the third light beam, the fourth light beam, the fifth light beam and the sixth light beam, and the reflector can respectively adjust the direction of the outgoing light path of the third light beam, the fourth light beam, the fifth light beam, the sixth light beam and the cutting beam.

[0017] As an improvement of the above solution, the mixed light beam at least includes light beams with wavelengths in the range of 1010-1055 nm and 1060-1090 nm respectively.

[0018] The light combining component can combine the 2n sub-beams into a cutting light beam having at least two focal points in the vertical direction.

[0019] In order to solve the above technical problems, the present invention also discloses a wafer multi-light spot cutting method, using the wafer multi-light spot cutting system as described above, comprising the following steps:

[0020] The mixed light beam is emitted by the mixed light emitter, wherein the mixed light beam includes at least two light beams with different wavelengths;

[0021] Splitting the mixed light beam into 2n sub-beams by a beam splitting component;

[0022] Adjust the focus of the 2n sub-beams through a beam expansion component;

[0023] Combining the 2n sub-beams into a cutting beam having at least two focal points in the same straight line direction by a light combining component, wherein n>0;

[0024] The cutting light beam is focused inside the wafer to achieve hidden cutting of the light spot.

[0025] As an improvement to the above scheme, the following steps are also included:

[0026] Splitting the mixed light beam into a first light beam and a second light beam by a first light splitter;

[0027] Splitting the first light beam into a third light beam and a fourth light beam by a second light splitter;

[0028] Splitting the second light beam into a fifth light beam and a sixth light beam by a third light splitter;

[0029] Combining the third light beam and the fifth light beam into a first combined light beam by a second light combining component;

[0030] Combining the fourth light beam and the sixth light beam into a second combined light beam by a third light combining component;

[0031] The first combined light beam and the second combined light beam are combined into a cut light beam by a fourth light combining component.

[0032] The implementation of the present invention has the following beneficial effects:

[0033] The wafer multi-light spot cutting system of the present invention is provided with a mixed light transmitter, a light splitting component, a light combining component and a beam expanding component, wherein the mixed light beam emitted by the mixed light transmitter includes at least two light beams of different wavelengths. Since the factors affecting the laser power are mainly the power density, pulse width and repetition frequency of the laser, and the wavelength has little effect on the cutting effect of the laser, using light beams of different wavelengths to cut the wafer will not affect the cutting effect, and the light beams of different wavelengths can be easily divided into multiple sub-beams by the light splitting component, wherein the light beams of different wavelengths can be separated by using light splitting components such as dichroic mirrors, and the separation loss is small, which can effectively Reduce the loss of light energy and improve the efficiency of the optical system. After separation, the focus of different light beams is adjusted by the beam expansion component, and then enters the light combining component to merge to form a cutting beam. The cutting beam can have at least two focuses in the straight direction, and especially ensures that there are at least two focuses in the vertical direction. In this way, when cutting thicker wafers, cutting can be performed at different positions of the cutting surface, dispersing the laser power, improving the uniformity of the cutting surface, ensuring the verticality, and reducing the power density of each cutting point. While reducing the generation of stress cracks, it also avoids the problem of thermal stress concentration caused by heat concentration, thereby greatly improving the yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a first embodiment of a wafer multi-light spot cutting system of the present invention;

[0035] Figure 2 It is a schematic diagram of the structure of each sub-beam of the second embodiment of the wafer multi-light spot cutting system of the present invention;

[0036] Figure 3 It is a structural schematic diagram of a second embodiment of a wafer multi-light spot cutting system of the present invention;

[0037] Figure 4 It is a schematic diagram of the process of the wafer multi-light spot cutting method of the present invention;

[0038] Figure 5 It is a schematic diagram of the process of beam splitting and beam combining in the wafer multi-light spot cutting method of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It is hereby stated that the directional terms such as up, down, left, right, front, back, inside, outside, etc. that appear or will appear in the text of the present invention are only based on the accompanying drawings of the present invention, and are not specific limitations of the present invention.

[0040] See also Figure 1 and Figure 2 An embodiment of the present invention discloses a wafer multi-light spot cutting system, including a mixed light transmitter 1 having at least two wavelength outputs, a beam splitter component 2, a beam combining component 3 and a beam expanding component 4. Different from a traditional laser transmitter, in the embodiment of the present invention, the mixed light beam 7 emitted by the mixed light transmitter 1 includes at least two light beams with different wavelengths, and the beam splitter component 2 can split the mixed light beam 7 into 2n sub-beams, where n>0.

[0041] In the embodiment of the present invention, the light splitting component 2 can split the mixed light beam 7 into a first light beam 71 and a second light beam 72 (when n=1) according to different wavelengths, and further, the first light beam 71 and the second light beam 72 can be respectively divided into n light beams, so the light splitting component 2 can split the mixed light beam 7 into 2n sub-beams (when n>1). The wavelength does not affect the cutting effect of the laser, because the cutting effect mainly depends on the power density, pulse width, repetition frequency and other parameters of the laser. Therefore, different light beams separated by different wavelengths will not have a large difference in cutting effect, which can ensure the uniformity of cutting. The 2n sub-beams can enter the beam expansion component 4, and the beam expansion component 4 can adjust the focus of different light beams. The beam expanding component 4 mainly includes a beam expander, which utilizes the focusing effect of the lens to transform the light beam from a smaller diameter and a larger divergence angle to a larger diameter and a smaller divergence angle through a combination of an input lens and an output lens. Therefore, after each sub-beam enters the beam expander, its respective diffusion angle can be changed, so that the focal points of each sub-beam can be staggered from each other, so as to facilitate subsequent adjustment to different vertical heights. After the 2n sub-beams enter the light combining component 3, they can be combined into a cutting light beam 8 with at least two focal points in a straight line direction. The straight line direction can be adjusted according to demand. In the embodiment of the present invention, it is mainly aimed at applications in the vertical straight line direction. In other embodiments, it can be an inclined direction or a horizontal direction. After merging the 2n sub-beams into a single cutting beam 8, since the cutting beam 8 has at least two focal points in the vertical direction, it is possible to cut at least two positions in the same longitudinal section of the wafer during cutting. During cutting, since the energy is evenly distributed to each cutting position, the longitudinal section is cut evenly, and the two focal points are located on the same straight line, so the flatness and verticality of the cutting can be guaranteed. By dispersing the cutting points, it is possible to avoid stress concentration and cracks, and to avoid thermal stress concentration, reduce edge collapse and cracking, and thus improve the yield and reliability of the wafer.

[0042] The beneficial effects of the embodiments of the present invention are as follows:

[0043] The wafer multi-light spot cutting system of the embodiment of the present invention is provided with a mixed light transmitter 1, a light splitting component 2, a light combining component 3 and a beam expanding component 4, wherein the mixed light beam 7 emitted by the mixed light transmitter 1 includes at least two light beams of different wavelengths. Since the factors affecting the laser power are mainly the power density, pulse width and repetition frequency of the laser, and the wavelength has little effect on the cutting effect of the laser, the use of light beams of different wavelengths to cut the wafer will not affect the cutting effect, and the light beams of different wavelengths can be easily divided into multiple sub-beams by the light splitting component 2, wherein the use of a light splitting component 2 such as a dichroic mirror can separate the light beams of different wavelengths, and the separation loss is small, which can be effective. Effectively reduce the loss of light energy and improve the efficiency of the optical system. After separation, the focus of different light beams is adjusted by the beam expansion component 4, and then enters the light combining component 3 to merge into a cutting beam 8. The cutting beam 8 can have at least two focuses in the straight direction, especially at least two focuses in the vertical direction. In this way, when cutting thicker wafers, cutting can be performed at different heights of the longitudinal section, dispersing the laser power, improving the uniformity of the longitudinal section cutting, ensuring the verticality, and reducing the power density of each cutting point. While reducing the generation of stress cracks, it also avoids the problem of thermal stress concentration caused by heat concentration, thereby greatly improving the yield.

[0044] In an embodiment of the present invention, the mixed light beam 7 includes at least two light beams in two wavelength ranges, preferably, the two wavelength ranges are 1010-1055nm and 1060-1090nm, respectively. In practical applications, the wavelengths of the two light beams should not differ too much to avoid affecting the consistency of the cutting effects of the two beams. In an embodiment of the present invention, the light combining component 3 is capable of combining 2n beams of the sub-beams into a cutting light beam 8 having at least two focal points in the vertical direction.

[0045] First embodiment:

[0046] See also Figure 1In the first embodiment of the present invention, n=1, and the beam splitting component 2 splits the mixed light beam 7 into two beams. The beam splitting component 2 includes a first beam splitting component 21. A portion of the mixed light emitted by the mixed light transmitter 1 is reflected in the first beam splitting component 21 to form a first beam 71, and the other portion passes through the first beam splitting component 21 to form a second beam 72. The first beam splitter 21 is preferably a dichroic mirror, which can separate the transmission and reflection of light of a specific wavelength. When light is incident on the dichroic mirror at a certain angle, light of a specific wavelength will be reflected, while light of other wavelengths will be transmitted. The first beam splitter 21 is set using the characteristics of the dichroic mirror, so that a part of the mixed light can be reflected to become the first light beam 71, and a light beam of another wavelength can penetrate the first beam splitter 21 to form the second light beam 72. Compared with the traditional semi-transparent and semi-reflective mirror, since the separation effect of the semi-transparent and semi-reflective mirror is based on the refraction and reflection characteristics of light, the light loss is relatively high, while the separation effect of the dichroic mirror is based on the wavelength characteristics of light, and light separation can be achieved without losing too much light energy, thereby reducing the loss of light power during splitting and improving the utilization rate of light power.

[0047] After beam splitting, in order to make the first light beam 71 and the second light beam 72 have different focal points, the beam expanding assembly 4 includes a first beam expander 41, and the first beam expander 41 is located on the exit light path of the first light beam 71 and / or the second light beam 72. The first beam expander 41 can adjust the diameter and divergence angle of the first light beam 71 and / or the second light beam 72, so that the focal points of the two can be located at different positions. The first beam expander 41 can be separately arranged on the exit light path of the first light beam 71 or the second light beam 72. As long as the diameter and divergence angle of one of the light beams are adjusted, the focal points of the two can be different. In other embodiments, they can also be arranged on the exit light paths of the first light beam 71 and the second light beam 72 at the same time, and the two light beams can be adjusted at the same time so that the focal positions of the two are different. In the first embodiment, in order to avoid the situation where light beams with different polarization states may interfere with or cancel each other out when they are combined, thereby causing uneven energy distribution, it is necessary to control the polarization directions of the first light beam 71 and the second light beam 72 after transmission and reflection. Specifically, after beam splitting, by setting a half-wave plate 5 in the output light path of the first light beam 71 and the second light beam 72, the first light beam 71 and the second light beam 72 can pass through the half-wave plate 5, respectively, and form light beams with intersecting polarization states, respectively. In this way, when the beams are combined, stable polarization coupling can be formed, thereby ensuring the uniformity and stability of energy.

[0048] In order to achieve beam combining, in the first embodiment, the light combining component 3 includes a first light combining component 31, and the first light combining component 31 is arranged on the output light path of the first beam expander 41. The first light beam 71 and the second light beam 72 can be combined into the cutting light beam 8 through the first light combining component 31. The first light combining component 31 is preferably a polarization splitter prism, which can combine two beams of light with different polarization directions into one light beam, namely the cutting light beam 8.

[0049] Second embodiment:

[0050] See also Figure 2 and Figure 3 In the second embodiment of the present invention, n=2, that is, the mixed light beam 7 is divided into 4 beams, wherein, as in the first embodiment, the mixed light beam 7 is divided into a first light beam 71 and a second light beam 72 through a first light splitter 21, wherein the wavelengths of the first light beam 71 and the second light beam 72 are different. On the basis of the first embodiment, the light splitter component 2 further includes a second light splitter 22, which is preferably a semi-reflective and semi-transparent mirror, a portion of the first light beam 71 passes through the second light splitter 22 to form a third light beam 711, and another portion is reflected by the second light splitter 22 to form a fourth light beam 712, and the second light splitter 22 divides the first light beam 71 into the third light beam 711 and the fourth light beam 712.

[0051] The spectroscopic component 2 also includes a third spectroscopic component 23, which is preferably a semi-reflective and semi-transparent component. A portion of the second light beam 72 is reflected by the third spectroscopic component 23 to form a fifth light beam 721, and another portion passes through the third spectroscopic component 23 to form a sixth light beam 722. Combined with the third light beam 711 and the fourth light beam 712, the spectroscopic component 2 finally splits the mixed light beam 7 into four light beams.

[0052] When combining beams, the light combining component 3 also includes a second light combining component 32, a third light combining component 33 and a fourth light combining component 34. The third light beam 711 and the fifth light beam 721 form a first combined light beam 81 in the second light combining component 32, the fourth light beam 712 and the sixth light beam 722 form a second combined light beam 82 in the third light combining component 33, and the first combined light beam 81 and the second combined light beam 82 form the cutting beam 8 in the fourth light combining component 34, thereby completing the beam combining.

[0053] In the second embodiment, the second light combining component 32 and the third light combining component 33 are both dichroic mirrors. When passing through the dichroic mirrors, light beams of specific wavelengths can pass through the dichroic mirrors, and light beams of other wavelengths can be reflected by the dichroic mirrors. By reasonably setting the reflection angles of the second light combining component 32 and the third light combining component 33, the outgoing light path of the third light beam 711 after being reflected by the second light combining component 32 can be overlapped with the outgoing light path of the fifth light beam 721 after passing through the second light combining component 32 to be combined into the first combined light beam 81, and the outgoing light path of the fourth light beam 712 after being reflected by the third light combining component 33 can be overlapped with the outgoing light path of the sixth light beam 722 after passing through the third light combining component 33 to be combined into the second combined light beam 82.

[0054] The fourth light combining component 34 that combines the first combined light beam 81 and the second combined light beam 82 into one light beam is preferably a polarization beam splitter prism. The polarization beam splitter prism can allow P polarized light to be completely transmitted and S polarized light to be completely reflected. The use of a polarization beam splitter prism can reduce optical power loss. The outgoing light path of the first combined light beam 81 after reflection from the fourth light combining component 34 coincides with the outgoing light path of the second combined light beam 82 after passing through the fourth light combining component 34, thereby combining the first combined light beam 81 and the second combined light beam 82 into the cutting light beam 8.

[0055] In order to control the focal positions of each light beam to be staggered, the beam expander 4 also includes a second beam expander 42, which is respectively located on the exit optical paths of at least three of the third light beam 711, the fourth light beam 712, the fifth light beam 721 and the sixth light beam 722. In the second embodiment, the second beam expander 42 only needs to be arranged on the exit optical paths of the three light beams. By controlling the focal positions of the three light beams to be staggered and not overlapped with the focal positions of another light beam, the focal positions of the four light beams can be different, and one of the second beam expanders 42 can be saved. In other embodiments, the beam expander 4 can be arranged on the exit optical paths of the four light beams to accurately control the position of each focal point.

[0056] Furthermore, in order to accurately control the polarization angles of the third light beam 711, the fourth light beam 712, the fifth light beam 721, and the sixth light beam 722, and to avoid the situation where light beams of different polarization states may interfere with or cancel each other when they are combined, thereby causing uneven energy distribution, the wafer multi-light spot cutting system further includes a half-wave plate 5, which can rotate the polarized light, and the half-wave plate 5 is respectively arranged on the exit light paths of the third light beam 711, the fourth light beam 712, the fifth light beam 721, the sixth light beam 722, and the cutting light beam 8, and by setting appropriate The third light beam 711 and the fifth light beam 721 can be adjusted to form S-polarized light, and the first combined light beam 81 formed by combining the third light beam 711 and the fifth light beam 721 is also S-polarized light, so that the first combined light beam 81 can reduce light loss when transmitting the fourth light combining component 34; the fourth light beam 712 and the sixth light beam 722 can be adjusted to form P-polarized light, and the second combined light beam 82 formed by combining the fourth light beam 712 and the sixth light beam 722 is also P-polarized light, so that the second combined light beam 82 can reduce reflection loss when passing through the fourth light combining component 34. At the final combination, the polarization beam splitter of the fourth light combining component 34 combines the S-polarized first combined light beam 81 and the P-polarized second combined light beam 82 into a cut light beam 8 with a complete polarization direction (SP polarized light).

[0057] During setting, a reflector 6 is provided at the turning point of the exit light paths of the third light beam 711, the fourth light beam 712, the fifth light beam 721 and the sixth light beam 722, and the reflector 6 can respectively adjust the directions of the exit light paths of the third light beam 711, the fourth light beam 712, the fifth light beam 721, the sixth light beam 722 and the cutting beam 8 to ensure that the first combined light beam 81 and the second combined light beam 82 can be formed respectively.

[0058] A focusing lens 9 is provided on the outgoing optical path of the cutting light beam 8 , and the focusing lens 9 can move in the Z axis to accurately control the depth of the focus of the laser light beam inside the wafer.

[0059] Referring to Table 1, in the present invention, the output powers of the light beams of different wavelengths in the mixed light beam are equal, and a dichroic mirror with a reflectivity or transmittance of >99% is used as the preferred solution for the first light splitter 21, the second light splitter 22 and the third light splitter 23, and a reflector 6 with a reflectivity of >99% is used as the solution for reflecting the light beam. When the inherent loss in the system is ignored (the fourth light combiner 34 has a power loss of about 5%, the first beam expander 41 and the second beam expander 42 have a power loss of about 15%, and the focusing lens 9 has a power loss of about 30%), an output efficiency of about 95% can be obtained in theory. In actual output, even if the inherent loss is taken into account, the present invention can still achieve an optical power utilization rate of more than 55%, which is about 3.7 times higher than the optical power utilization rate of some existing multi-light spot cutting systems (about 15%), greatly improving the optical power utilization rate, thereby saving a lot of costs.

[0060]

[0061]

[0062] Table 1 Optical power utilization of each sub-beam at each stage

[0063] See also Figure 4 The present invention also discloses a wafer multi-light spot cutting method, which uses the wafer multi-light spot cutting system as described above to cut the wafer, comprising the following steps:

[0064] S01, emitting a mixed light beam through a mixed light emitter, wherein the mixed light beam includes at least two light beams with different wavelengths;

[0065] S02, splitting the mixed light beam into 2n sub-beams by a beam splitting component;

[0066] S03, adjusting the focus of the 2n sub-beams through a beam expansion component;

[0067] S04, combining the 2n sub-beams into a cutting beam having at least two focal points in the same straight line direction by a light combining component, wherein n>0;

[0068] S05, focusing the cutting light beam inside the wafer to achieve hidden cutting of the light spot.

[0069] In the wafer multi-spot cutting method of the present invention, the beam splitter component 2 can split the mixed light beam 7 into a first light beam 71 and a second light beam 72 (when n=1) according to different wavelengths, and further, the first light beam 71 and the second light beam 72 can be respectively divided into n light beams, so the beam splitter component 2 can split the mixed light beam 7 into 2n sub-beams (when n>1). The beam expansion component 4 utilizes the focusing effect of the lens, and through the combination of the input lens and the output lens, transforms the light beam from a smaller diameter and a larger divergence angle to a larger diameter and a smaller divergence angle. Therefore, after each sub-beam enters the beam expander, it can change its respective diffusion angle, so that the focus of each sub-beam can be staggered to form different focal positions on the same straight line. In the embodiment of the present invention, it is mainly aimed at applications in the vertical straight line direction. In other embodiments, it can be an inclined direction or a horizontal direction. After the light beam is split, it is also necessary to merge the 2n sub-beams into a single beam to facilitate cutting of the wafer. The light combining component can combine the 2n sub-beams into a cutting beam having at least two foci in the same straight line direction. Since the cutting beam 8 has at least two foci in the vertical direction, at least two positions in the same longitudinal section of the wafer can be cut during cutting. During cutting, since the energy is evenly distributed to each cutting position, the longitudinal section is cut evenly, and the two foci are located on the same straight line, so the flatness and verticality of the cutting can be guaranteed. Moreover, by dispersing the cutting points, it is possible to avoid stress concentration and cracks, and to avoid thermal stress concentration, reduce edge collapse and cracks, thereby improving the yield and reliability of the wafer.

[0070] Furthermore, the wafer multi-light spot cutting method further comprises the following steps:

[0071] S21, splitting the mixed light beam into a first light beam and a second light beam by a first light splitter;

[0072] S22, splitting the first light beam into a third light beam and a fourth light beam by a second light splitter;

[0073] S23, splitting the second light beam into a fifth light beam and a sixth light beam by a third light splitter;

[0074] S41, combining the third light beam and the fifth light beam into a first combined light beam by a second light combining component;

[0075] S42, combining the fourth light beam and the sixth light beam into a second combined light beam by a third light combining component;

[0076] S43: Combine the first combined light beam and the second combined light beam into a cut light beam by using a fourth light combining component.

[0077] The first beam splitter 21 is preferably a dichroic mirror, which can separate the transmission and reflection of light of a specific wavelength. When light is incident on the dichroic mirror at a certain angle, light of a specific wavelength will be reflected, while light of other wavelengths will be transmitted. The first beam splitter 21 is set using the characteristics of the dichroic mirror, so that a part of the mixed light can be reflected to become the first light beam 71, and a light beam of another wavelength can penetrate the first beam splitter 21 to form the second light beam 72. Compared with the traditional semi-transparent and semi-reflective mirror, since the separation effect of the semi-transparent and semi-reflective mirror is based on the refraction and reflection characteristics of light, the light loss is relatively high, while the separation effect of the dichroic mirror is based on the wavelength characteristics of light, and light separation can be achieved without losing too much light energy, thereby reducing the loss of light power during splitting and improving the utilization rate of light power.

[0078] In order to further disperse the energy and increase different focal points, the first light beam and the second light beam are respectively divided into four light beams, wherein the second light splitter 22 is preferably a half-reflecting half-mirror, a part of the first light beam 71 passes through the second light splitter 22 to form a third light beam 711, and the other part is reflected by the second light splitter 22 to form a fourth light beam 712, the second light splitter 22 divides the first light beam 71 into the third light beam 711 and the fourth light beam 712, the third light splitter 23 is preferably a half-reflecting half-mirror, a part of the second light beam 72 is reflected by the third light splitter 23 to form a fifth light beam 721, and the other part passes through the third light splitter 23 to form a sixth light beam 722, combined with the third light beam 711 and the fourth light beam 712, the light splitter assembly 2 finally splits the mixed light beam 7 into four light beams. The four light beams can obtain focal points at different positions through different beam expanders, so when cutting, four positions in the same longitudinal section of the wafer can be cut, and energy is evenly distributed during cutting, which not only improves cutting uniformity but also avoids thermal stress concentration.

[0079] See also Figure 5When combining, the third light beam 711 and the fifth light beam 721 form a first combined light beam 81 in the second light combining component 32, the fourth light beam 712 and the sixth light beam 722 form a second combined light beam 82 in the third light combining component 33, and the first combined light beam 81 and the second combined light beam 82 form the cutting light beam 8 in the fourth light combining component 34. The second light combining component 32 and the third light combining component 33 are both dichroic mirrors. When passing through the dichroic mirrors, light beams of specific wavelengths can pass through the dichroic mirrors, and light beams of other wavelengths can be reflected by the dichroic mirrors. By reasonably setting the reflection angles of the second light combining component 32 and the third light combining component 33, the outgoing light path of the third light beam 711 after being reflected by the second light combining component 32 can be overlapped with the outgoing light path of the fifth light beam 721 after passing through the second light combining component 32 to be combined into the first combined light beam 81, and the outgoing light path of the fourth light beam 712 after being reflected by the third light combining component 33 can be overlapped with the outgoing light path of the sixth light beam 722 after passing through the third light combining component 33 to be combined into the second combined light beam 82. The fourth light combining component 34 that combines the first combined light beam 81 and the second combined light beam 82 into one light beam is preferably a polarization beam splitter prism. The use of a polarization beam splitter prism can reduce optical power loss, and the outgoing light path of the first combined light beam 81 after reflection from the fourth light combining component 34 coincides with the outgoing light path of the second combined light beam 82 after passing through the fourth light combining component 34, thereby combining the first combined light beam 81 and the second combined light beam 82 into the cutting light beam 8.

[0080] The above are preferred embodiments of the present invention. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A wafer multi-spot cutting system, characterized in that: It comprises a mixed light emitter with at least two wavelength outputs, a beam splitter component, a beam expander component and a beam combiner component, wherein the mixed light beam emitted by the mixed light emitter comprises at least two light beams with different wavelengths, the beam splitter component can split the mixed light beam into 2n sub-beams, and the 2n sub-beams can adjust the focus of different light beams through the beam expander component; After entering the light combining component, the 2n sub-beams can be combined into a cutting light beam having at least two focal points in the same straight line direction; wherein n>0.

2. The wafer multi-spot cutting system according to claim 1, characterized in that: The light splitting component comprises a first light splitting element, a part of the mixed light emitted by the mixed light emitter is reflected in the first light splitting element to form a first light beam, and another part passes through the first light splitting element to form a second light beam.

3. The wafer multi-spot cutting system according to claim 2, characterized in that: The beam expanding assembly includes a first beam expanding lens, which is located on the exit light path of the first light beam and / or the second light beam. The light combining assembly includes a first light combining component, which is located on the exit light path of the first beam expanding lens. The first light beam and the second light beam can be combined into the cutting beam by passing through the first light combining component.

4. The wafer multi-spot cutting system according to claim 2, characterized in that: The beam splitter assembly further comprises a second beam splitter and / or a third beam splitter, a portion of the first beam passes through the second beam splitter to form a third beam, and another portion is reflected by the second beam splitter to form a fourth beam; A portion of the second light beam is reflected by the third light splitter to form a fifth light beam, and another portion of the second light beam passes through the third light splitter to form a sixth light beam.

5. The wafer multi-light spot cutting system according to claim 4, characterized in that: The second beam splitter and the third beam splitter are both semi-reflective and semi-mirror lenses.

6. The wafer multi-spot cutting system according to claim 4, characterized in that: The light combining component also includes a second light combining component, a third light combining component and a fourth light combining component. The third light beam and the fifth light beam form a first combined light beam in the second light combining component, the fourth light beam and the sixth light beam form a second combined light beam in the third light combining component, and the first combined light beam and the second combined light beam form the cutting beam in the fourth light combining component.

7. The wafer multi-light spot cutting system according to claim 6, characterized in that: The second light combining element and the third light combining element are both dichroic mirrors, the outgoing light path of the third light beam after being reflected by the second light combining element coincides with the outgoing light path of the fifth light beam after passing through the second light combining element, and the outgoing light path of the fourth light beam after being reflected by the third light combining element coincides with the outgoing light path of the sixth light beam after passing through the third light combining element; The fourth light combining component is a polarization beam splitter prism, and an outgoing light path of the first combined light beam after being reflected by the fourth light combining component coincides with an outgoing light path of the second combined light beam after passing through the fourth light combining component.

8. The wafer multi-spot cutting system according to claim 4, characterized in that: The beam expansion assembly also includes a second beam expander, which is respectively located on the outgoing light paths of at least three light beams among the third light beam, the fourth light beam, the fifth light beam and the sixth light beam.

9. The wafer multi-light spot cutting system according to claim 4, characterized in that: The wafer multi-light-spot cutting system further comprises a half-wave plate, which is respectively arranged on the exit light paths of the third light beam, the fourth light beam, the fifth light beam, the sixth light beam and the cutting light beam.

10. The wafer multi-spot cutting system according to claim 4, characterized in that: Reflectors are provided at the turning points of the outgoing light paths of the third light beam, the fourth light beam, the fifth light beam and the sixth light beam, and the reflectors can respectively adjust the directions of the outgoing light paths of the third light beam, the fourth light beam, the fifth light beam, the sixth light beam and the cutting light beam.

11. The wafer multi-spot cutting system according to claim 1, characterized in that: The mixed light beam at least includes light beams with wavelengths in the range of 1010-1055nm and 1060-1090nm respectively; The light combining component can combine the 2n sub-beams into a cutting light beam having at least two focal points in the vertical direction.

12. A wafer multi-spot cutting method, using the wafer multi-spot cutting system according to any one of claims 1 to 11, characterized in that: The following steps are involved: The mixed light beam is emitted by the mixed light emitter, wherein the mixed light beam includes at least two light beams with different wavelengths; Splitting the mixed light beam into 2n sub-beams by a beam splitting component; Adjust the focus of the 2n sub-beams through a beam expansion component; Combining the 2n sub-beams into a cutting beam having at least two focal points in the same straight line direction by a light combining component, wherein n>0; The cutting light beam is focused inside the wafer to achieve hidden cutting of the light spot.

13. The wafer multi-light spot cutting method according to claim 12, characterized in that: The following steps are also included: Splitting the mixed light beam into a first light beam and a second light beam by a first light splitter; Splitting the first light beam into a third light beam and a fourth light beam by a second light splitter; Splitting the second light beam into a fifth light beam and a sixth light beam by a third light splitter; Combining the third light beam and the fifth light beam into a first combined light beam by a second light combining component; Combining the fourth light beam and the sixth light beam into a second combined light beam by a third light combining component; The first combined light beam and the second combined light beam are combined into a cut light beam by a fourth light combining component.

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