Fuzhou University and others have made another breakthrough in Micro LED mass transfer technology

Recently, according to external news, Fuzhou University and Chalmers University of Technology in Sweden have made important progress in the Micro LED mass transfer process.

The research team successfully developed an ultra-high-yield Micro led laser bulk light transfer method without residual polymers. This result is expected to greatly increase the commercialization speed of Micro LEDs in cutting-edge display applications such as AR/VR, wearables, and smart glasses. < p style =' margin: 0px 0px 0.25 rem; padding: 0px; border: 0px; outline: 0px; color: rgb (51, 51, 51); font-family: -apple-system," Helvetica Neue ", Arial," PingFang SC "," Hiragino Sans GB ", STHeiti," Microsoft YaHei "," Microsoft JhengHei "," Source Han Sans SC "," Noto Sans CJK SC "," Source Han Sans CN "," Noto Sans SC "," Source Han Sans TC "," Noto Sans CJK TC "," WenQuanYi Micro Hei ", SimSun, sans-serif; font-size: 18px; text-align: justify; text-indent: 0px; '> The research team adopted a laser-induced transfer scheme combined with big data packet analysis and empirical mathematical models to effectively improve the accuracy and yield of chip transfer. This method achieves a very high chip retention rate by controlling the laser stripping energy in the range of 1200–1500 mJ/cm ²; in the subsequent secondary transfer stage, when the laser energyThe transfer yield is 100% when the density of measurement meets a specific relationship with the depth of sinking of the chip and the laser spot size is 30 x 38 microns. < p style = 'margin: 0px 0px 0.25 rem; padding: 0px; border: 0px; outline: 0px; color: rgb (51, 51, 51); font-family: -apple-system, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", STHeiti, "Microsoft YaHei", "Microsoft JhengHei", "Source Han Sans SC", "Noto Sans CJK SC", "Source Han Sans CN", "Noto Sans SC", "Source Han Sans TC", "Noto Sans CJK TC", "WenQuanYi Micro Hei ", SimSun, sans-serif; font-size: 18px; text-align: justify; text-indent: 0px; '> The research team said that traditional bulk transfer technologies such as electrostatic adsorption, micro seals, or roller seals have many limitations in large-scale applications. For example, electrostatic transfer may damage the chip due to charge accumulation, micro stamps are limited to lithographic accuracy, and roller stamps are difficult to achieve the required alignment accuracy. The laser transfer technology proposed this time not only precisely controls the laser focus depth, but also avoids chip surface damage and transfer offset, with excellent stability and flexibility. < p style =' margin: 0px 0px 0.25 rem; padding: 0px; border: 0px; outline: 0px; color: rgb (51, 51, 51); font-family: -apple-system," Helvetica Neue ", Arial," PingFang SC "," Hfont-size: 18px; text-align: justify; text-indent: 0px;'>The study also found that during the transfer of the chip to the second temporary carrier, the final alignment accuracy is easily affected by polymer bases such as PDMS (polydimethylsiloxane). 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 caused by sapphire warping and uneven bonding, and achieved uniformity without polymer residue for the first time.Precise transfer of sinking.

More importantly, this technology is suitable for Micro LED chips of various sizes and types, and has good scalability and compatibility. This lays a solid foundation for better transfer of Micro LED chips to TFT (thin film transistor) drive substrates.

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.elvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", STHeiti, "Microsoft YaHei", "Microsoft JhengHei", "Source Han Sans SC", "Noto Sans CJK SC", "Source Han Sans CN", "Noto Sans SC", "Source Han Sans TC", "Noto Sans CJK TC", "WenQuanYi Micro Hei", SimSun, sans-serif; font-size: 18px; text-align: justify; text-indent: 0px;'>It is worth noting that Fuzhou University is a national new display technology innovation center and a Micro LED display innovation platform. It is engaged in 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 chip-substrate bonding.

In recent years, Fuzhou University has continued to cooperate with enterprises and universities at home and abroad to carry out Micro led technology research. Among them, in terms of enterprise cooperation, in July last year, Fuzhou University, Mindu Laboratory, and Fuzhou Jiaxin Chuanghui Electromechanical 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. < p style =' margin: 0px 0px 0.25 rem; padding: 0px; border: 0px; outline: 0px; color: rgb (51, 51, 51); font-family: -apple-system, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", STHeiti, "Microsoft YaHei", "Microsoft JhengHei", "Source Han Sans SC", "Noto Sans CJK SC", "Source Han Sans CN", "Noto Sans SC", "Source Han Sans TC", "Noto Sans CJK TC", "WenQuanYi Micro Hei", SimSun, sans-serif; font-size: 18px; text-align: justify; text-indent: 0px;'>Just in May this year, Heimixing announced that it had successfully developed China's first wafer-level Micro LED chip non-contact electroluminescence inspection in cooperation with Fuzhou UniversityThe testing engineering prototype FED-NCEL realizes non-contact electroluminescence testing of red, green and blue Micro LED epitaxial wafers, wafers and temporary carrier chips.

In terms of university cooperation, last year, Fuzhou University cooperated with Fujian Institute of Materials, Wenzhou Institute of Technology, Shenzhen University and other universities to achieve a number of research results related to Micro led, such as high-efficiency near-infrared quantum dot phosphors, QLED device performance improvement, and new color conversion display performance improvement, and continued to promote the development of Micro led technology.