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Accuracy and efficiency of chip placement process play a critical role in electronic packaging technology since it can determine the success ratio and throughput of chip packaging system. In this paper, a new motional chip placement process is proposed to improve the process efficiency, where the chip is placed onto the substrate with a contact velocity. However, the moving chip is also more likely to produce position drift on the anisotropic conductive adhesive, which will result in low accuracy of chip placement process. In view of this, a three-layer model considering the effect of the chip contact velocity is presented to address the dynamic behavior of chip placement process, where the geometrical dimensions and material properties of this model are included. In addition, the mechanism of motional chip placement process is uncovered, and the effects of key factors, including chip length, adhesive viscosity, and chip contact velocity on chip motion, are analyzed. The results show that the moving chip is helpful for the efficiency of chip placement process, but it also may cause low accuracy of chip placement process. Finally, in order to select appropriate key factors, the technical criteria are discussed, and the process window for reliable motional chip placement is established and verified by experiments. [ABSTRACT FROM AUTHOR]

Chip picking-up with vacuum sorption is a critical technology in flip-chip packaging for separating chip intactly from donor adhesive tape. With increasing length/thickness ratio of chips, the incomplete separation affects the success rate of this process, even leads to the failure of chips. Here, we present a theoretical model with a bisection algorithm to calculate the effective size of tape that contributes to the crack growth, and introduce an energy release rate and pick-up force to evaluate the ability of thin chip picking-up. The finite-element method with a virtual crack-closure technique is constructed to validate the established process model. The effects of the type of pick-up head, length of chip, thickness, and material of tape on chip picking-up process are also revealed to improve the ability to propagate a crack in the adhesive layer. Furthermore, the crack propagation in the adhesive layer with increasing pick-up displacement is predicted to determine the critical value of the thin chip complete separation from compliant tape. These results suggest that the thinner and more compliant tape should be adopted in the chip picking-up process. [ABSTRACT FROM PUBLISHER]