Experimental Study on Crack Propagation of Adhesive Layer Within Mini-LED Chips Needle-Ejecting Peeling-Off Transfer Mode

In this study, an experimental platform for crack propagation of the adhesive layer within mini-LED chips needle-ejecting peeling-off transfer mode is designed and constructed to visualize the transfer process and identify the factors affecting peeling-off performances. The expanded UV film with UV photosensitive acrylic adhesive is adopted in the experiments. Mini-LED chips with uniform circumferential spacing are used in crack propagation experimental investigation, in which single-factor controlled variable experiments are designed to explore the effects of film type, initial height of the chip, and position of the ejecting force exerted on crack propagation of mini-LED flying needle-ejecting peeling-off transfer mode. The experimental findings indicate that UV film is superior for the peeling off of mini-LED chips due to its superior tensile strength and adjustable viscosity. It is beneficial to utilize the noneccentric peeling-off mode rather than the eccentric mode to achieve good transfer accuracy. Furthermore, based on the results obtained from the crack propagation experiment, the dual-gantry mini-LED flying needle-ejecting peeling-off mass transfer equipment co-developed with Suzhou Maxwell Technologies Company Ltd., Suzhou, China, is used to carry out chip-on-glass bonding performances study under both slow and rapid transfer patterns.