Analysis of Laser Scribing Technology in LED Wafer Production

Laser scribing LED scribing lines are much narrower than traditional mechanical scribing, so the material utilization rate is significantly improved, thus improving output efficiency. In addition, laser processing is a non-contact process. Scribing brings less wafer micro-cracks and other damage, which makes the wafer particles closer together, with high output efficiency and high productivity. At the same time, the reliability of the finished LED device is also greatly improved. improve.　　With the continuous growth of the market, the LED manufacturing industry's requirements for production capacity and yield have become higher and higher. Laser processing technology has quickly become a common tool in the LED manufacturing industry, and even has become the industry standard for high-brightness LED wafer processing.　　 Laser scribing LED scribing lines are much narrower than traditional mechanical scribing, so the material utilization rate is significantly improved, thus increasing the output efficiency. In addition, laser processing is a non-contact process. Scribing brings less wafer micro-cracks and other damage, which makes the wafer particles closer together, with high output efficiency and high productivity. At the same time, the reliability of the finished LED device is also greatly improved. improve.　　Industrial laser has the advantages of high peak power and excellent beam quality. It is an ideal tool for LED processing, bringing clean scribing lines, higher productivity and higher brightness of finished LEDs to the LED industry. The advantages of laser scribing can cleanly and neatly scribe hard and brittle materials, non-contact process, low operating costs, reduce the appearance of chipping, micro-cracks, delamination and other defects, narrow scribe lines, increase the number of particles on a single wafer Microcracks improve the long-term reliability of the finished LED device. The large-scale processing tolerance makes the process controllable, and it is a low-cost and high-reliability process.　　 Overview of LED laser scribing　　 Single crystal sapphire (Sapphire) and gallium nitride (GaN) are hard and brittle materials (tensile strength close to steel), so it is difficult to cut into individual LED devices. When cutting these materials with traditional mechanical saw blades, it is easy to cause damages such as wafer chipping, micro-cracks, delamination, etc. Therefore, when cutting LED wafers with saw blades, a wide width must be reserved between the monomers to avoid cutting cracks. And LED devices, this greatly reduces the output efficiency of LED wafers. Laser cutting machine processing is non-contact processing. As an alternative to traditional mechanical saw cutting, the laser scribing incision is very small, and the focused laser's fine spot on the wafer surface quickly vaporizes the material, and is manufactured between the LED active areas Very small incision, which can cut more LED monomers on a wafer with a limited area. Laser scribing is particularly good at gallium arsenide (GaAS) and other brittle compound semiconductor wafer materials. For laser processing of LED wafers, the typical scoring depth is 1/3 to 1/2 of the substrate thickness. This division can obtain clean fracture surfaces, creating narrow and deep laser scoring cracks while ensuring high-speed scribing speed. Lasers are required to have excellent qualities such as narrow pulse width, high beam quality, high peak power, and high repetition rate. Not all lasers are suitable for LED scribing because of the transparency of the wafer material for visible wavelength lasers. GaN is transmissive to light with a wavelength of less than 365nm, while sapphire wafers are semi-transmissive to lasers with a wavelength greater than 177nm. Therefore, three- and four-frequency Q-switched all-solid-state lasers (DPSSL) with wavelengths of 355nm and 266nm are LED crystals. Choice of round laser scribing. Although excimer lasers can also achieve the wavelength required for LED marking, frequency-doubled all-solid-state Q-switched lasers are smaller and less maintenance than excimer lasers. In terms of quality, all-solid lasers have very narrow marking lines and are more suitable Scribe by laser LED.　　Laser scribing greatly reduces wafer micro-cracks and micro-crack expansion, and the distance between LED monomers is closer, which improves production efficiency and productivity. Generally speaking, a 2-inch wafer can separate more than 20,000 LED single devices. With such a high density, the width of the dicing slit will significantly affect the number of particles. The long-term reliability of LED devices will also be significantly improved. Compared with traditional blade cutting, laser scribing not only improves output efficiency, but also increases processing speed, avoiding processing defects and cost losses caused by blade wear. In short, laser processing has high precision, large processing tolerances, and low cost. The key market for DPSS all-solid-state lasers requires high reliability and long continuous operation time. One-click laser LED scribing process with optimized parameters. 266nm All solid lasers are used for front scribing of LED wafers. 355nm is used for back scribing. Global service and technical support Network short pulse width and high peak power to achieve deep scribing, thermal damage is minimized, high-quality beam quality to achieve small scribing width, laser suppliers have strong application development strength and experience