TW202030782A - Laser pre-dividing method and device for LED wafer sheet - Google Patents

Abstract

The invention discloses a laser pre-dividing method and device for an LED wafer sheet. The device comprises a super-fast laser device, a laser transmission assembly, a non-diffraction light beam generation module, a focus objective lens, a vision detection device and a motion platform. The vision detection device is located at the upper portion of the focus objective lens, the motion platform is located at the lower portion of the focus objective lens and used for bearing the LED wafer sheet, and the focus objective lens is an imaging objective lens of the vision detection device. The super-fast laser device emits super-short pulse laser beams, reshaping is conducted through the laser transmission assembly, high-precision circular light spots are obtained, then, the high-precision circular light spots are irradiated into the non-diffraction light beam generation module, non-diffraction light beams are generated, and machining light beams for pre-dividing of the LED wafer sheet are formed through focusing of the focus objective lens. By means of the laser pre-dividing method and device, the defects that due to traditional laser cutting, inclined cracks, back collapse, large and small edges and the like are caused can be effectively overcome, and the problem that during directly-formed non-diffraction light beam sheet scratching, electrode faces are damaged can be solved as well.

Description

Laser pre-segmentation method and device of LED wafer

The invention relates to the technical field of laser processing, in particular to a laser pre-segmentation method and device for LED wafers.

As a new generation of lighting technology, LED is widely used in many fields of national life due to its energy saving, environmental protection, high efficiency and low energy consumption. Among them, LED light sources can replace traditional light sources to reduce energy consumption by more than 50%. Therefore, the development of this technology is important for my country Commercial development and improvement of people's living standards are of great significance. Sapphire substrate is one of the most widely used materials in the LED industry. Its crystal characteristics (specifically expressed in the two directions of easy-to-cut and difficult-to-cut perpendicular to each other) make the wafers divided into single devices have certain oblique cracks and may affect the final Good product rate and single device performance. Compared with the traditional mechanical scribing and dividing into a single device, the laser stealth dicing technology is a non-contact processing and quickly occupy the market with its many advantages. Specific advantages include: clean and neat scribing of all current LEDs with sapphire, silicon, silicon carbide, etc. as substrates, which can reduce chipping defects such as chipping and micro-cracks, narrow scribing lines, and improve wafers with the same area Dividing the number of single devices has strong operability and high efficiency, and can reduce production costs. However, the current laser stealth dicing technology used in the LED industry uses the Gaussian beam directly output by the laser, which still has certain shortcomings. For example, the yield rate after dicing still has a large room for improvement, and cracks in the modified layer are caused The performance of the device is reduced, and the oblique crack angle is large after cutting.

With the development of the LED industry and the continuous growth of market demand, it has put forward more requirements on the currently widely used laser wafer dicing technology. Traditional Gaussian beam stealth dicing is no longer sufficient to meet the application development in this field. demand. For example, optical devices with special shapes and sizes suitable for applications in different industries are being used more and more. The predetermined dividing line and the size of a single device are constantly being reduced to increase the output quantity, yield and performance requirements of a single device after division. More and more advanced, these have higher standards for the modified layer shape, oblique crack angle, and electrode surface damage after dicing. There are more and more researches on the laser cutting of LED wafers in this field. For example, invention patent CN102194931 A discloses a method of improving the modified layer after laser processing to increase the luminous brightness of the split optical device. Invention patent CN1575909 A and CN103537805 A propose a method of adding a laser modified layer by multiple light spots or multiple processing to obtain a better segmentation effect. The above documents all reflect the important role of modified layer optimization for LED wafer segmentation, and also point out the direction for the improvement of laser scribing technology.

Compared with Gaussian beams, non-diffracted beams have the characteristics of non-divergence in the propagation direction, extremely small center spot, and self-healing after encountering obstacles during propagation. Application of it to LED wafer dicing is expected to achieve a more regular improvement in molding. It can also scribe wafers with narrower dicing channels, which can inject new impetus into the development of laser stealth cutting technology. As shown in Figure 3, the use of traditional Gaussian light for internal modification has a very narrow modified layer, which tends to cause more cracks and large oblique crack angles in the section after cutting. The wider width of the modified layer can realize the cutting of higher quality cross-sections; however, the non-diffracted beam under normal conditions is cut due to its formation method and beam characteristics (under normal circumstances, the energy of the front and rear ends in the propagation direction of the non-diffracted beam Low, this part of the energy is not beneficial to substrate dicing) It is very easy to cause damage to the electrode surface with low damage threshold. This phenomenon is more obvious when cutting the CH1 surface of the LED sapphire substrate due to the small dot pitch and larger pulse energy input (Figure 4). Therefore, how to make full use of the advantages of non-diffraction beams and avoid their shortcomings to apply it to LED wafer dicing is very important.

Therefore, the conventional technology needs to be improved and developed.

In view of the shortcomings of the above-mentioned conventional technology, the purpose of the present invention is to provide a method and device for laser pre-segmentation of LED wafers, so as to overcome the oblique cracks, back breaks, and back-cracks that are easily caused by the conventional LED wafer pre-segmentation methods. Defects such as large and small edges, and the problem of destroying the electrode surface.

The technical scheme of the present invention is as follows:

The present invention provides a laser pre-segmentation device for LED wafers, which includes: an ultrafast laser, a laser transmission component, a non-diffraction beam generation module, a focusing objective lens, a visual inspection device, and a motion platform;

The visual inspection device is located on the upper part of the focusing objective lens, the moving platform is located on the lower part of the focusing objective lens for carrying LED wafers, and the focusing objective lens is the imaging objective lens of the visual inspection device;

The ultra-fast laser emits an ultra-short pulse laser beam, which is shaped by the laser transmission component to obtain a high-precision circular spot, and then enters the non-diffraction beam generation module to generate a non-diffraction beam, which is then focused by a focusing objective lens to form a Pre-segment the processing beam of the LED wafer.

In the laser pre-segmentation device for LED wafers, the laser transmission component includes a laser beam shrinking lens, a hole-shaped attenuation device, and a fast switching light pulse output control device arranged in sequence along the beam transmission direction;

The ultra-short pulse laser beam emitted by the ultra-fast laser first obtains a high-precision spot with a divergence angle of less than 1 milliradian and a diameter of less than 1 mm through the laser beam reduction lens, and then the roundness of the spot is improved by a hole-shaped attenuation device. Then, the output of the light beam is controlled by the fast switching light pulse output control device.

In the laser pre-segmentation device for LED wafers, the non-diffracting beam generating module includes an axicon.

In the laser pre-segmentation device for LED wafers, the pulse width of the ultra-short pulse laser beam generated by the ultra-fast laser is less than 1000 picoseconds.

In the laser pre-segmentation device for LED wafers, the visual inspection device includes a CCD camera.

The laser pre-segmentation device for LED wafers, wherein the laser pre-segmentation device further includes a half-reflecting half-lens arranged between the visual inspection device and the focusing objective lens, and the non-diffracting beam generated by the non-diffracting beam generating module It first enters the half mirror and then partially reflects into the focusing objective lens.

In the laser pre-segmentation device of the LED wafer, wherein the multiple of the focusing objective lens is greater than 10 times and the numerical aperture is greater than 0.3.

The present invention further provides a laser pre-segmentation method for LED wafers, which includes the steps:

Provide any one of the above-mentioned laser pre-segmentation devices;

After placing the LED wafer on the moving platform, adjust the visual inspection device and the moving platform to locate the predetermined dividing line of the LED and feedback the position of the focus point in the sample at this time;

Turn on the ultra-fast laser to emit an ultra-short pulse laser beam, which is shaped by the laser transmission component to obtain a high-precision circular spot, and then enters the non-diffracted beam generating module to generate a non-diffracted beam, and then enters the focusing objective lens;

Adjust the moving platform and the focusing objective lens for precise focusing, and focus the processing beam formed by the focusing objective lens on the selected area inside the substrate, so that the processing beam can accurately internally modify the LED wafer along the predetermined dividing line to achieve pre-segmentation.

In the laser pre-segmentation method of the LED wafer, during the laser pre-segmentation of the wafer, the width of the modified layer is adjusted and controlled by the laser transmission component or the non-diffraction beam generation module, and the width of the modified layer is adjusted and controlled by the focusing objective lens and the moving platform The adjustment of the focus position realizes the adjustment of the position of the modified layer.

In the laser pre-segmentation method for LED wafers, the high-precision circular spot has a beam diameter of less than 1 mm and a divergence angle of less than 1 milliradian.

The beneficial effects of the present invention are:

In the present invention, a high-precision circular spot is obtained by shaping by a laser transmission component, and then incident on the non-diffracting beam generating module to generate a non-diffracting beam, processing the inside of the sapphire substrate and forming a modified layer, which is obtained after subsequent splits The cross-section of each device is formed regularly, which can effectively avoid the defects such as oblique cracks, back collapses, and large and small edges caused by traditional laser cutting, and can also solve the problem of electrode surface damage when scribing directly generated non-diffraction beams; secondly, the obtained low damage The modified layer can improve the strength and optical performance of a single device after segmentation; and processing by this method can achieve large dot pitch pre-segmentation, which can achieve higher efficiency in actual production.

The present invention provides a laser pre-segmentation method and device for LED wafers. In order to make the objectives, technical solutions and effects of the present invention clearer and clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

Refer to Figure 1, which shows the pre-splitting optical path of the LED wafer laser based on the non-diffracted beam. An embodiment of the present invention provides a laser pre-segmentation device 100 for LED wafers, which includes: an ultrafast laser 110, a laser transmission component 140, a non-diffraction beam generating module 150, a focusing objective lens 170, and visual inspection The device 200 and the moving platform 210; the visual inspection device 200 is located on the upper part of the focusing objective lens 170, the moving platform 210 is located under the focusing objective lens 170 for carrying the LED wafer 220, the focusing objective lens 170 is the imaging objective lens of the visual inspection device 200; the focusing objective lens 170 , The visual inspection device 200 and the motion platform 210 constitute a focus positioning system for cutting positioning and precise focusing during the cutting process of LED wafers; the ultra-fast laser 110 emits an ultra-short pulse laser beam with a pulse width of less than 1 ns. The laser transmission component 140 is shaped to obtain a high-precision circular spot, which is then incident on the non-diffracted beam generating module 150 to generate a non-diffracted beam, and then focused by the focusing objective lens 170 to form a processing beam for pre-segmenting the LED wafer 220.

In the present invention, a high-precision circular spot is obtained by shaping by a laser transmission component, and then incident on the non-diffracting beam generating module to generate a non-diffracting beam, processing the inside of the sapphire substrate and forming a modified layer, which is obtained after subsequent splits The cross-section of each device is formed regularly, which can effectively avoid defects such as oblique cracks, back collapses, and large and small edges caused by traditional laser cutting, and can also solve the problem of electrode surface damage when dicing directly formed non-diffraction beams; secondly, obtain low damage The modified layer can improve the strength and optical performance of a single device after segmentation; and processing by this method can achieve large dot pitch pre-segmentation, which can achieve higher efficiency in actual production.

Further, in this embodiment, the laser transmission component includes a laser beam shrinking lens, a hole-shaped attenuation device, and a fast switching optical pulse output control device arranged in sequence along the beam transmission direction; the ultra-short pulse emitted by the ultra-fast laser The laser beam first obtains a high-precision spot with a divergence angle of less than 1 milliradian and a diameter of less than 1 mm through the laser beam reduction lens, and then improves the roundness of the spot through a hole-shaped attenuation device, and then quickly switches the light pulse output control device Control the output of the high-precision circular spot. The laser beam reduction lens controls the diameter and divergence angle of the directly generated beam, and the hole-shaped attenuation device realizes the small spot roundness control device to ensure that the generated non-diffracted beam can meet the corresponding requirements of LED division and the electrode surface No burn effects. The response time of the fast switching optical pulse output control device is not more than 1 microsecond, that is, the switching interval time is less than 1 microsecond. The hole-shaped attenuation device can increase the roundness by at least 96%. The hole attenuation is mainly to further optimize the energy division of the small spot. In specific implementation, a small hole can be simply set to achieve the effect. Preferably, an attenuator with a similar effect can be used to achieve the effect, which can avoid beams under high energy. The interaction.

Further, in this embodiment, the non-diffraction beam generating module includes an axicon or other components or systems that can achieve the same effect. The pulse width of the ultra-short pulse laser beam produced by the ultrafast laser is less than 1000 picoseconds, and the single pulse energy is not less than 20 microjoules. The laser wavelength is not limited to 1030 nm and can be focused on the sapphire substrate to modify it Processing. The visual inspection device includes a CCD camera. As shown in Fig. 1, the laser pre-segmenting device 100 further includes a half mirror 130 arranged between the visual inspection device 200 and the focusing objective lens 170. The non-diffracted beam generated by the non-diffracted beam generating module 150 is first incident on the half. The reverse half lens 130 is partially reflected back into the focusing objective lens 170. The multiple of the focusing objective lens 170 is greater than 10 times and the numerical aperture is greater than 0.3.

During specific implementation, a 125-micron thick sapphire substrate LED wafer can be used for pre-segmentation. Figure 1 is a schematic diagram of an LED wafer laser pre-segmentation device based on a non-diffracting beam used in the present invention. The processing beam generated by the laser 110 enters the focusing objective 170 through the mirror 120 and the half mirror 130, and the half mirror The semi-lens 130 can also be used with the visual inspection device 200 and the focusing objective 170 to realize processing, observation and cutting positioning; the beam needs to be shaped by a specific laser transmission component 140 before passing through the non-diffraction beam generating module 150, and the resulting non-diffraction The light beam passes through the lens 160 and enters the focusing objective lens 170 (50 times, NA is 0.5) to form a beam that can be used for processing and pre-segment the LED wafer 220 placed on the moving platform 210. In actual processing, the selection of the shape of the modified layer can be realized by adjusting the specific laser transmission component 140. The specific laser transmission component 140 shapes the laser beam and then passes through the non-diffraction beam generating module 150 is the key to the realization of the effect of the invention. Here, the beam is first used to obtain a divergence angle of less than 0.8 through a laser beam reducer (the narrowing range is adjustable) For a milliradian spot with a diameter of less than 1 mm, the beam directly output by the laser is shaped by a hole-shaped attenuation device to increase the roundness of the small spot. The fast switching optical pulse output control device in the assembly is located behind the attenuation device.

Further, in this embodiment, the laser cutting device further includes a control system for controlling the ultrafast laser 110, the laser transmission assembly 140, the focusing objective lens 170, the visual inspection device 200, and the motion platform 210. Realize the control of wafer or focus objective lens during processing, and can realize automatic control of cutting positioning and focusing process.

As shown in Figure 2, an embodiment of the present invention further provides a laser pre-segmentation method for LED wafers, which includes:

Step S100, providing the laser pre-segmentation device;

Step S200: After placing the LED wafer on the moving platform, adjust the visual inspection device and the moving platform to locate the predetermined dividing line of the LED wafer and feedback the position of the focus point in the sample at this time;

Step S300: Turn on the ultra-fast laser to emit an ultra-short pulse laser beam, which is shaped by the laser transmission component to obtain a high-precision circular spot, and then enters the non-diffracted beam generating module to generate a non-diffracted beam, and then enters the focus Objective lens

Step S400, adjust the moving platform and the focusing objective lens for precise focusing, and focus the processing beam formed by the focusing objective lens on the selected area inside the LED wafer, so that the processing beam is performed on the LED wafer (sapphire substrate) along the predetermined dividing line Precise internal modification to achieve pre-segmentation.

In specific implementation, locate the predetermined dividing line of the LED in the visual monitoring equipment and its control system and feedback the position of the focus point in the sample at this time, and then focus the non-diffracted beam required for processing on the inside of the substrate through the relevant components. Select the area, and finally, under the motion control and visual monitoring system, the processing beam is extended to the predetermined line to perform precise internal modification of the sapphire substrate to achieve pre-segmentation.

Further, in this embodiment, the high-precision circular spot has a beam diameter of less than 1 mm and a divergence angle of less than 1 milliradian. During wafer laser pre-segmentation, the width of the modified layer is adjusted and controlled by the laser transmission component or the non-diffraction beam generating module, and the position of the modified layer is adjusted by adjusting the focus position of the focusing objective lens and the moving platform. The non-diffracted light beam generated after passing through a specific laser transmission component acts on the inside of the sapphire substrate, and the width and position of the formed modified layer are adjustable. The width of the modified layer can be controlled by a non-diffraction beam generation system or a laser transmission component, and the position of the modified layer can be achieved by motion control and adjustment of the focus position of the vision system, which can be based on actual needs when ensuring the subsequent split effect select.

Furthermore, in this embodiment, after processing the modified layer with a non-diffraction beam, a single straight crack can be observed on the surface of the sapphire and the split is convenient; there is no direction shift at the intersection of the two cracks even when cutting in two directions crosswise , Can effectively solve the problem of oblique crack and back collapse in actual production. After optimizing the processing parameters, the modified layers of the two cutting directions of sapphire are well formed and no cracks appear except for the modified area, which can ensure the optical performance and strength of a single device after segmentation. When cutting sapphire in two directions, only modify it with different point spacing to obtain the ideal processing effect, and the processing point spacing in one direction can reach at least 20 microns, which provides the possibility for efficient automatic processing or reducing processing costs.

Further, in this embodiment, the surface of the wafer has a predetermined dividing line and has been divided into a plurality of optical device arrays. This method focuses the laser beam along the predetermined dividing line on the inside of the wafer substrate to form a modified layer and achieve the desired result Split effect. This method is based on processing the interior of the sapphire substrate to form a modified layer based on the non-diffracted light beam generated by a specific laser transmission component. The width of the modified layer formed by the processing can be selected according to the thickness of the substrate or the actual processing requirements to meet different practical applications demand. The cross-section of each device obtained by the pre-segmentation method after subsequent splitting is regular, which can effectively avoid oblique cracks and electrode surface damage caused by traditional laser cutting, and can also improve the strength and optical performance of a single device after cutting. The actual cutting of the sapphire substrate wafer found that the adjustment of the transmission component can realize the processing and cutting with a large dot pitch, which can achieve higher efficiency in actual production; it can also not burn the electrode surface after changing the position of the modified layer.

The advantages of the laser pre-segmentation method for LED wafers of the present invention are: 1) Based on the method, the non-diffracted light beam can be used to adjust the width of the modified layer, which can meet wafer dicing of different specifications and processing requirements, and The cross-section forming of the separated single device is significantly improved compared with the traditional laser scribing; 2) With this method, even if the processing point spacing is greater than 20 microns, it can still achieve a regular single device segmentation, which greatly reduces the laser action area. It is possible to improve the efficiency and the luminous performance and intensity of a single device after segmentation; 3) The crack straightness after cross scribing in two directions can be well maintained even at the intersection point, which can cause defects such as back collapse and large and small edges. Provide solutions.

The present invention will be described in detail below with specific embodiments:

Example 1

The aforementioned processing device is provided, and the laser transmission assembly 140 is adjusted to obtain a circular beam with a diameter of about 1 mm. After placing the selected sapphire substrate LED wafer on the processing platform, use the coaxial imaging vision system to accurately find the surface of the sapphire substrate, and then use the motion control system to move the objective lens a certain distance to make the processing beam (selected laser wavelength) It is 1030 nanometers and the pulse width is adjustable, and the direct output spot is about 3 mm.) Focus on the selected position inside the sapphire. After completing the above processing position determination steps, under the selected custom process parameters (pulse width 13 picoseconds, single pulse energy 30 microjoules), the horizontal and vertical directions are respectively pre-divided (in view of the manufacturing process of the sapphire substrate wafer, processing in both directions The dot pitch is 6 microns and 24 microns respectively). After the laser is pre-divided, an automated splitting device is used to completely separate the wafer into individual devices to observe the separation and cross-sectional effects.

From the results obtained in Example 1, it can be seen from Figure 5 that the two directions are pre-divided and the subsequent splits are formed regularly, especially the cracks formed after cutting the sapphire substrate in two directions can be completely perpendicular at the intersection point, and are completely perpendicular to the fourth After the non-diffracted beam formed by the direct transmission of the laser is cut, the electrode surface appears black spots to form a sharp contrast, and there is no damage to the electrode surface after this method is pre-divided. Compared with the traditional Gaussian beam cutting section (Figure 3), the section morphology, oblique cracks and electrode surface protection obtained by the method are significantly improved.

Example 2

Place the selected sapphire substrate long-grain LED wafer (select the direction where the sapphire is relatively easy to cut for comparison) after placing it on the processing table and use the coaxial imaging vision system to accurately find the surface of the sapphire substrate, and then use the motion control system to The focusing objective material is fixed to make the laser focus on the specific area inside the sapphire for internal modification. As experiment 1, the attenuation device is used to adjust the incident laser energy distribution (different attenuation ratio adjustment in the circular spot) to achieve the same width modification. Cutting at different point spacings in the case of the quality layer. In addition, in the case of determining the width of the modified layer and the distance between the cutting points, the laser transmission component 140 is used to adjust the energy distribution of the incident light, and the position of the modified layer can be adjusted after the focal point of the objective lens is set at different positions inside the sapphire , This condition is used as experiment three. Furthermore, when the focus position of the focus objective lens 170 is determined, the effective length of the non-diffracted beam output by the focus objective lens 170 and the energy distribution of the outer ring can be adjusted by the beam reduction device control of the laser transmission component 140, and the internal modification of the sapphire can be realized For the regulation of layer width, this condition is used as experiment two. After completing the above steps, the laser is pre-divided and then the wafer is separated into strips by the automatic splitting device to observe the separation and cross-sectional effect.

From the results obtained in Example 2, it can be seen from Fig. 6 that this method can realize the segmentation of different modified layer morphologies with the adjustment of the laser transmission component and the segmentation parameters. It is worth noting that even if the position of the modified layer is set in the lower part of the sapphire substrate, better cutting can be achieved without affecting the electrode surface (Figure 6(c)), which ensures that the non-diffraction beam is cut. This advantage is fully utilized in LED wafer dicing. Furthermore, the width of the modified layer can be adjusted in conjunction with the adjustment of the transmission components, and wafer dicing of different specifications can be easily realized.

It should be understood that the application of the present invention is not limited to the above examples. For those with ordinary knowledge in the technical field, they can make improvements or changes based on the above descriptions. All these improvements and changes should belong to the attached patent application of the present invention. The scope of protection.

100: Laser pre-segmentation device for LED wafers 110: Ultrafast laser 120: mirror 130: half mirror half lens 140: Laser transmission component 150: Non-diffraction beam generation module 160: lens 170: focus objective 200: Visual inspection device 210: Motion Platform 220: LED wafer S100, S200, S300, S400: steps

FIG. 1 is a schematic structural diagram of a laser pre-segmentation device for LED wafers according to an embodiment of the present invention. FIG. 2 is a flowchart of the laser pre-segmentation method of LED wafers according to an embodiment of the present invention. Figure 3 shows the ratio of cut cross-sections of traditional Gaussian light and non-diffraction beam sapphire substrate; among them, (a) shows that the cross-section cracks are more and the width of the modified layer is narrow after traditional Gaussian light cutting, and (b) is non-diffraction beam cutting A modified layer with a larger width can be obtained. Figure 4 is the result of electrode surface damage caused by dicing in the direction of the non-diffracted beam CH1 that is not directly formed by the laser transmission component. Figure 5 is a diagram showing the effect of complete splitting of the sapphire substrate LED in two directions in Example 1. Among them, (a) is a non-diffraction beam directly formed by a laser transmission component without any damage to the electrode surface, and (b) is a sapphire surface Obtain excellent straightness, (c) and (d) are CH2 and CH1, respectively, the cross-sections are formed regularly and without cracks. Figure 6 is the cross-sectional cutting effect diagram of embodiment 2 after adjusting the shape of different modified layers in the CH2 direction by adjusting the beam transmission components; among them, (a) is cutting with small dot pitch, (b) is cutting with large dot pitch, (C) is the adjustment of the position of the modified layer, (d) is the adjustment of the width of the modified layer.

100: Laser pre-segmentation device for LED wafers

110: Ultrafast laser

120: mirror

130: half mirror half lens

140: Laser transmission component

150: Non-diffraction beam generation module

160: lens

170: focus objective

200: Visual inspection device

210: Motion Platform

220: LED wafer

Claims (10)

A laser pre-segmentation device for LED wafers, comprising: an ultra-fast laser, a laser transmission component, a non-diffraction beam generating module, a focusing objective lens, a visual inspection device, and a motion platform; The visual inspection device is located on the upper part of the focusing objective lens, the moving platform is located on the lower part of the focusing objective lens for carrying the LED wafer, and the focusing objective lens is the imaging objective lens of the visual inspection device; The ultrafast laser emits an ultrashort pulse laser beam, which is shaped by the laser transmission component to obtain a high-precision circular spot, which is then incident on the undiffracted beam generating module to generate an undiffracted beam, and then passes through The focusing objective lens focuses to form a processing beam used for pre-segmenting the LED wafer. The laser pre-segmentation device for LED wafers according to claim 1, wherein the laser transmission component includes a laser beam reducing lens and a hole-shaped laser beam reducing lens arranged in sequence along the transmission direction of the ultrashort pulse laser beam Attenuation device and a fast switching optical pulse output control device; The ultra-short pulse laser beam emitted by the ultrafast laser first obtains the high-precision circular spot with a divergence angle of less than 1 milliradian and a diameter of less than 1 mm through the laser beam reducing lens, and then passes through the hole-shaped attenuation The device improves the roundness of the high-precision circular light spot, and then the output of the high-precision circular light spot is controlled by the fast switching light pulse output control device. The laser pre-segmentation device for LED wafers according to claim 1, wherein the undiffracted beam generating module includes an axicon. The laser pre-segmentation device for LED wafers according to claim 1, wherein the pulse width of the ultra-short pulse laser beam generated by the ultra-fast laser is less than 1000 picoseconds. The laser pre-segmentation device for LED wafers according to claim 1, wherein the visual inspection device includes a CCD camera. The laser pre-segmentation device for LED wafers according to claim 1, wherein the laser pre-segmentation device further includes a half mirror arranged between the visual inspection device and the focusing objective lens, and the undiffracted light beam generates The undiffracted light beam generated by the module first enters the half mirror, and then partially reflects into the focusing objective lens. The laser pre-segmentation device for LED wafers according to claim 1, wherein the multiple of the focusing objective lens is greater than 10 times and the numerical aperture is greater than 0.3. A laser pre-segmentation method for LED wafers, which includes the following steps: Provide the laser pre-segmentation device as described in any one of claims 1 to 7; After placing the LED wafer on the moving platform, adjust the visual inspection device and the moving platform to locate the predetermined dividing line of the LED wafer and feedback the position of the focus point in the sample at this time; The ultrafast laser is turned on to emit the ultrashort pulse laser beam, which is shaped by the laser transmission component to obtain the high-precision circular spot, and then enters the undiffracted beam generating module to generate the undiffracted beam, Incident on the focusing objective lens; Adjust the moving platform and the focusing objective lens for precise focusing, and focus the processing beam formed by the focusing objective lens on the selected area inside the LED wafer, so that the processing beam is performed on the LED wafer along the predetermined dividing line Precise internal modification to achieve pre-segmentation. The laser pre-segmentation method of the LED wafer according to claim 8, wherein the LED wafer is pre-segmented by the laser, the laser transmission component or the non-diffracting beam generation module is adjusted, controlled and modified The layer width is adjusted by adjusting the focus position of the focusing objective lens and the moving platform to realize the adjustment of the position of the modified layer. The laser pre-segmentation method of LED wafers according to claim 8, wherein the high-precision circular spot has a beam diameter of less than 1 mm and a divergence angle of less than 1 milliradian.

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