What are the bottlenecks in mass production of Mini/MicroLED chips that can be solved by large-scale transfer equipment

The display industry was once embroiled in a technology roadmap dispute between Mini LED and Micro LED, and to this day, these two major technology routes have found their respective suitable application areas. Performs differently in different applications.

Micro LED applications on mobile phones have energy-saving characteristics, high resolution, but also high price sensitivity. If used on smartwatches, it has the advantages of high brightness and energy efficiency, but low resolution and high price sensitivity. If used in splicing display, it can have the advantages of 0 borders, high brightness, customization, and achieve moderate resolution, with low price sensitivity. Therefore, Micro LED technology is more suitable for application in display scenarios such as car mounted, transparent, and ultra large splicing, and its advantages are also more obvious. In addition, with the rise of the AR market, the application of Micro LEDs in this field is also increasing.

The fact that needs to be faced is that although Micro LED has found suitable areas, Micro LED chips are still in the stage of breaking through the bottleneck of mass production, and the industry generally believes that the market is expected to enter a mature period after 2030. Mini products have gradually started to take off, making them relatively mature products.

It should be noted that multiple Mini/MicroLED chips are required in a Mini/MicroLED display screen. For example, the 12.9-inch MiniLED backlight of the iPad Pro uses over 10000 MiniLED chips, and the direct display MiniLED product (1080p) requires over six million chips. As an important equipment used in the key process of chip post packaging and testing, the production efficiency of the solidification machine (SMT machine) has met higher requirements.

To solve the problem of mass production, it is necessary to first see where its bottleneck lies. You Yi, the director of Yitian Semiconductor's massive transfer project, mentioned at an industry forum that both Mini LED and Micro LED face certain production challenges, including issues in materials, processes, MURA effects, equipment, and other aspects.

MURA includes poor chip flatness after welding, differences in board color caused by multiple furnace passes, and differences in chip emission bands; The process faces problems of low transfer efficiency and high difficulty in repair. In terms of materials, there are limitations such as PCB flatness, weak glass substrate circuit structure, and high costs for chips and PCB boards. In addition, there are also issues with poor coherence and low pass through rate of the entire line equipment.

Traditional SMT single crystal machines are suitable for chip transfer processes with large spacing and size. Its UPH (production speed) is difficult to exceed 30K pcs/H, for example, the accuracy of medium and high precision solidification machines is about ± 25 μ M. In terms of accuracy, it is approximately ± 20 μ m. The yield rate is approximately 99.999%. Moreover, the higher the accuracy and speed, the faster the UPH will be, and it will be more prone to deviation.

In order to address the challenges that Mini/Micro LED iteration brings to production efficiency, it is necessary to improve the production efficiency, product yield, and accuracy of the solidification machine. And massive transfer technology is the key technology for the industrialization of mini/Micro LED chips.

Plexinzhi has also launched the Mini/MicroLED massive transfer device XBond Pro. According to the introduction, the product adopts the inverted COB crystal piercing process, with a maximum UPH of 720K and support of 10 μ M~800 μ The chip size of m. Yino Laser also announced in December 2023 that it will lay out a large-scale transfer process demonstration line.
In the future, with the joint efforts of upstream and downstream enterprises in the Mini/Micro LED industry chain, especially the R&D investment of large-scale transfer equipment manufacturers, the mass production capacity of Mini/Micro LED chips will be further improved.