An LED chip cutting system with back metal plating and high reflectivity film

Abstract

The utility model relates to a kind of LED chip cutting systems of back plating metal and high reflectivity film, including the laser source of ultraviolet laser and infrared laser;Ultraviolet laser is connected with the first beam shaper below, and infrared laser is connected with the second beam shaper below;The first beam shaper and the second beam shaper are connected with the beam combiner below, and the beam combiner receives the light path from the first beam shaper and the second beam shaper respectively;The beam combiner is connected with scanning galvanometer below;Scanning galvanometer is connected with achromatic objective below, and the cutting system of the utility model utilizes the physical characteristics of ultraviolet laser and infrared laser, cooperation, realizes the collaborative processing effect of film breaking first, then cutting body.

Description

Technical Field

[0001] This utility model relates to an LED chip cutting system with back-plated metal and high reflectivity film, belonging to the field of LED chip manufacturing technology. Background Technology

[0002] Traditional LED stealth cutting solutions typically use a single wavelength (usually infrared) laser for processing; however, this presents a significant challenge when dealing with workpieces with complex back coating layers.

[0003] For example, in LED chip manufacturing, the structural reference of chip 10 Figure 2 and Figure 3 As shown: Chip 10 includes a substrate 12 made of sapphire. An enhanced reflectivity coating 11 is deposited on the back side of the substrate 12. The coating 11 is typically a metal film or a DBR film. An epitaxial layer 13 is provided on the bottom surface of the substrate 11. A current blocking layer 14 is provided at the bottom of the epitaxial layer 13. A P electrode 15 is located below the current blocking layer 14, and an N electrode 16 is located at the bottom of the epitaxial layer 13. The coating 11, the substrate 12, and the epitaxial layer 13 are a whole. Then, a single chip is obtained by laser cutting at the cutting position.

[0004] The coating 11 has high reflectivity or strong absorption for infrared lasers. High reflectivity will lead to low energy utilization and difficulty in cutting; strong absorption will lead to severe ablation or even spattering of the film layer, contamination and damage to the device, and macroscopic cracks in the substrate due to excessive thermal stress.

[0005] In the existing technology, there is a scheme that uses a single ultraviolet laser for cutting, which takes advantage of its "cold processing" characteristics to reduce the heat impact. However, for a thicker substrate 12, the penetration depth of the ultraviolet laser is limited, and extremely high pulse energy is required to complete the internal modification, which is inefficient and may cause damage to the upper surface. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing an LED chip cutting system with a back-plated metal and a high-reflectivity film.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: an LED chip cutting system with back-plated metal and high reflectivity film, comprising a laser source composed of an ultraviolet laser and an infrared laser; The ultraviolet laser is connected to the first beam shaper below, and the infrared laser is connected to the second beam shaper below. Both the first beam shaper and the second beam shaper are connected to the beam combiner below, and the beam combiner receives the optical paths from the first beam shaper and the second beam shaper, respectively. The lower part of the beam combiner is connected to the scanning galvanometer; The lower part of the scanning galvanometer is connected to the achromatic objective lens.

[0008] Furthermore, the ultraviolet laser is a 355nm ultraviolet laser.

[0009] Furthermore, the ultraviolet laser has the following characteristics: number of pulses: 1, speed: 200-1000 mm / s, power: 0.2-0.5 W, cutting depth: 8-15 μm, and cutting width: 8-12 μm.

[0010] Furthermore, the infrared laser is a 1064nm infrared laser.

[0011] Furthermore, the infrared laser has the following pulse counts: 1-12, speed: 200-1000 mm / s, power: 0.3-1.5 W, and cutting depth: 30-100 μm.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention utilizes the high photon energy and low thermal effect of ultraviolet lasers to act on DBR dielectric films, thereby destroying their film structure, causing them to lose their function or reducing their bonding force. This opens up a low-loss, unobstructed channel for subsequent infrared lasers. Taking advantage of the strong penetrability and high efficiency of interaction between infrared laser and substrate material, it is focused inside the substrate and forms a uniform and continuous modified layer through nonlinear effects such as multiphoton absorption, thus achieving efficient stealth cutting. This allows for the division of labor and collaboration between infrared and ultraviolet lasers, achieving a synergistic processing effect of first breaking the membrane and then cutting the body. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the LED chip structure; Figure 3 This is a state diagram of the LED chip after it has been cut. Legend: 10 - Chip, 20 - Cutting system; 11-Covering film, 12-Substrate, 13-Epipolar layer, 14-Current blocking layer, 15-P electrode, 16-N electrode; 21-Ultraviolet laser, 22-Infrared laser, 23-First beam shaper, 24-Second beam shaper, 25-Beam combiner, 26-Scanning galvanometer, 27-Achromatic objective lens. Detailed Implementation

[0014] Please see Figure 1This utility model provides a technical solution: an LED chip cutting system with back-plated metal and high reflectivity film, wherein the cutting system 20 includes a laser source b composed of an ultraviolet laser 21 and an infrared laser 22; Laser source b is connected to beam combining optical path c, which includes a first beam shaper 23 below the ultraviolet laser 21, a second beam shaper 24 below the infrared laser 22, and a beam combining mirror 25 connected to the first beam shaper 23 and the second beam shaper 24. The beam combiner 25 receives the optical paths from the first beam shaper 23 and the second beam shaper 24, respectively. The lower part of the beam combiner 25 is connected to the scanning galvanometer 26; The lower part of the scanning galvanometer 26 is connected to the achromatic objective lens 27.

[0015] The working process of this cutting system is as follows: Ultraviolet laser 21 and infrared laser 22 emit ultraviolet and infrared lasers respectively. The ultraviolet and infrared lasers pass through the first beam shaper 23 and the second beam shaper 24 respectively, and then enter the beam combiner 25 to combine them into a single beam containing both ultraviolet and infrared lasers. This single beam then passes through the scanning galvanometer 26 and the achromatic objective lens 27 before illuminating the cutting position of the chip 10. Figure 2 The dashed line indicates the cutting position. By utilizing the physical characteristics of ultraviolet laser and infrared laser, they work together to achieve the collaborative processing of first breaking the film and then cutting the body, thereby dividing the chip 10.

[0016] The ultraviolet laser 21 used in this invention is a 355nm ultraviolet laser, and the infrared laser 22 is a 1064nm infrared laser. Among them, the 355nm ultraviolet laser has a laser frequency of 100-150KHZ, a pulse number of 1 (single pulse), a speed of 200-1000mm / S, a power of 0.2-0.5W, a cutting depth of 8-15um, and a cutting width of 8-12um; The laser frequency of the 1064nm infrared laser is 50-200kHz, the number of pulses is 1-12, the speed is 200-1000mm / s, the power is 0.3-1.5W, and the cutting depth is 30-100um (1 / 3-1 / 2 of the wafer thickness). The principle of this cutting system is as follows: utilizing the physical characteristics of ultraviolet lasers and infrared lasers, they work together to achieve a coordinated processing effect of first breaking the membrane and then cutting the material. Specifically: Taking advantage of the high photon energy and low thermal effect of ultraviolet lasers, when applied to the DBR dielectric film coated with film 11, the film structure can be destroyed, causing it to lose its function or reduce its bonding force, thus opening a low-loss, unobstructed channel for infrared lasers.

[0017] Taking advantage of the strong penetrability and high efficiency of interaction between infrared laser and substrate 12, the laser is focused inside the substrate 12 layer and a uniform and continuous modified layer is formed through nonlinear effects such as multiphoton absorption, thereby achieving efficient body stealth cutting.

[0018] Ultraviolet lasers can only cut the surface and cannot reach the interior of the sapphire substrate 12, while infrared lasers can only form a modified layer inside the substrate 12. By integrating the characteristics of both infrared and ultraviolet lasers, the LED chip with a metal backing and a high reflectivity film can be successfully cut.

[0019] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Variations and modifications made without departing from the spirit and scope of this utility model fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An LED chip cutting system with a back-plated metal and high-reflectivity film, characterized in that: This includes laser sources composed of ultraviolet lasers and infrared lasers; The ultraviolet laser is connected to the first beam shaper below, and the infrared laser is connected to the second beam shaper below. Both the first beam shaper and the second beam shaper are connected to the beam combiner below, and the beam combiner receives the optical paths from the first beam shaper and the second beam shaper, respectively. The lower part of the beam combiner is connected to the scanning galvanometer; The lower part of the scanning galvanometer is connected to the achromatic objective lens.

2. The LED chip cutting system with back-plated metal and high-reflectivity film according to claim 1, characterized in that: The ultraviolet laser is a 355nm ultraviolet laser.

3. The LED chip cutting system with back-plated metal and high-reflectivity film according to claim 2, characterized in that: The ultraviolet laser has the following characteristics: number of pulses: 1, speed: 200-1000 mm / s, power: 0.2-0.5 W, cutting depth: 8-15 μm, and cutting width: 8-12 μm.

4. The LED chip cutting system with back-plated metal and high-reflectivity film according to claim 1, characterized in that: The infrared laser is a 1064nm infrared laser.

5. The LED chip cutting system with back-plated metal and high-reflectivity film according to claim 4, characterized in that: The infrared laser has the following pulse counts: 1-12, speed: 200-1000 mm / s, power: 0.3-1.5 W, and cutting depth: 30-100 μm.

Images