Mechanism Study for High-Yield Mass Transfer of Micro-LEDs Using a Blister-Type Dynamic Release Layer

Abstract

Abstract Micro light-emitting diodes (Micro-LEDs) miniaturize conventional LEDs to the micrometer scale (<50 μm) for high-density display integration, yet mass transfer remains the critical bottleneck for commercialization. In this study, laser-induced forward transfer (LIFT) with a blister-type dynamic release layer (DRL) was employed to achieve contactless mass transfer. We first conducted a comprehensive simulation-based investigation of blister growth and chip transfer dynamics from chip-on-carrier 1 (COC1) to chip-on-carrier 2 (COC2). The results reveal three key correlations: (i) blister height and internal pressure exhibit a nonlinear positive correlation with laser energy and pulse width; (ii) the laser spot area incident on the DRL is positively correlated with the initial propulsive force on the chip; and (iii) the offset distance between the laser spot and the chip center is positively correlated with the chip’s rotation angle upon landing on COC2, with rotation occurring in the same direction as the offset. Guided by these simulation insights, experiments were performed under optimized conditions: an energy density of 400 mJ/cm2, a pulse width of 10 ns, a transfer gap of 40 μm, and position-dependent spot sizes [Transfer Position 1 (TP1) and TP2: 30 μm × 38 μm; TP3: 40 μm × 32 μm; TP4: 40 μm × 36 μm]. Under these conditions, the successful transfer of a 40 × 40 Micro-LED array was achieved, with the DRL material utilization reaching 100%. This optimized transfer solution accelerates the path toward large-scale Micro-LED manufacturing.