The research team successfully developed an ultra-high yield Micro LED laser massive light transfer method without residual polymer. The results are expected to besignificantly>Improve the commercialization speed of Micro LED in cutting-edge display applications such as AR/VR, wearable devices, and smart glasses.
The research team adopted a laser-induced transfer (Laser-Induced Transfer) solution, combined with big data group analysis and empirical mathematical models, to effectively improve the accuracy and yield of chip transfer. This method achieves an extremely high chip retention rate by controlling the laser stripping energy within the range of 1200–1500 mJ/cm²; in the subsequent secondary transfer stage, when the laser energy density and chip sinking depth meet a specific relationship, and the laser spot size is 30×38 microns, the transfer yield rate reaches 100%.
The research team stated that traditional mass transfer technologies such as electrostatic adsorption, micro-seal or roller seal have many limitations in large-scale applications. For example. , electrostatic transfer may damage the chip due to charge accumulation, micro-stamping is limited by photolithography accuracy, and roller stamping is difficult to achieve the required alignment accuracy. The laser transfer technology proposed this time can not only accurately control the laser focus depth, but also avoid chip surface damage and transfer offset, and has excellent stability and flexibility.
The study also found that during the process of transferring the chip to the second temporary carrier, it is easy to causePDMS(polydimethylsiloxane)and other polymer groups affect the final alignment accuracy. In this regard, the research team established a mathematical relationship between the chip sinking depth and the optimal laser energy, which effectively compensated for the instability factors caused by sapphire warpage and uneven bonding, and achieved precise transfer without polymer residue and uniform sinking for the first time.
More importantly, this technology is suitable for many sizes and types of Micro LEDchip has good scalability and compatibility. This lays a solid foundation for Micro LEDchip to be better transferred to TFT (thin film transistor) drive substrate
In the future, the research team plans to further expand the application potential of this technology in full-color Micro LED, flexible display, micro-projection and other fields.
It is worth noting that FuzhouUniversity is the National New Display Technology Innovation Center, Micro The LED display innovation platform focuses on basic research, common key technologies and process equipment, technology verification and industrial demonstration applications, patents and standards, and discipline construction.It has strong technology leadership and application experience in design and talent training.
Currently, Fuzhou University has achieved a series of research results on technical difficulties such as μLED display light-emitting chip preparation, mass transfer of chips and micron-scale chips (Micro IC), and bonding of chips and substrates.
In recent years, Fuzhou University has continued to cooperate with enterprises and domestic and foreign universities to carry out Micro LED technology research. Among them, in terms of corporate cooperation, in July last year, Fuzhou University, Mindu Laboratory, and Fuzhou Jiaxin Chuanghui Mechanical and Electrical Company jointly reached a cooperation with Haimuxing , focusing on the iterative upgrading of key processes in the new display field and the development and innovation of a new generation of disruptive technologies
Just in May this year, Haimixing announced that and cooperated with Fuzhou University to successfully develop the first domestic wafer-level Micro LED chip non-contact electroluminescence detection engineering prototype FED-NCEL, which realized the detection of red, green and blue Micro Contactless electroluminescence inspection of LED epitaxial wafers, wafers and temporary carrier chips.
In terms of university cooperation, last year, Fuzhou University worked with Fujian Institute of Physics and Structure, Wenzhou Institute of Technology , Shenzhen University and many other universities have cooperated to achieve high-efficiency near-infrared quantum dot phosphor , QLED device performance improvement, new color conversion display performance improvement and many other Micro LED-related research results continue to promote the development of Micro LED technology.
ANNA