Research On Mechanism And Key Technologies Of Deterministic Micro Transfer Printing For Flexible Electronics

As the rapid development of flexible electronics,the related fabrication technologies have received extensive attentions.Deterministic micro transfer printing is a key link in the fabrication of flexible electronics,so it is of great theoretical and practical value to carry out the research on the key technologies of deterministic micro transfer printing.Aiming to improve the efficiency and the success rate of micro transfer printing,the mechanism and key technologies of micro transfer printing are studied in this dissertation.The main contents are shown as follows:In order to improve the efficiency of micro transfer printing,the influences of the technological parameters on the performance of the stamp used in micro transfer printing are studied.The transfer printing process is considered as the crack propagation of the “sandwich” model.Considering the influences of the prepressure,the peeling speed and the viscoelastic property of the stamp on the adhesion force of the stamp,a theoretical model is proposed according to the theory of fracture mechanics,which can reflect the micro transfer printing process.The effects of the prepressure and peeling speed on the adhesion force of the stamp are studied by experiments,which also verifies the correctness of the theoretical model.This research can provide effective theoretical guidance for the geometry and shape optimization of the stamps,as well as the micro transfer printing operation.Based on the bionic theory,a novel stamp with micro chamber and micro channel is proposed.A theoretical model of the pressure change in the micro chamber is established and the effects of extraction distance and extraction velocity on the adsorption force of the stamp are investigated.The performance test results show that the adsorption force of the stamp can be controlled by the extraction distance and the extraction velocity.This research effectively solves the problem that the adhesion force control of microstructured stamp is cumbersome,and provides a basis for improving the success rate of micro transfer printing.In order to improve the rotation angle adjustment capability of the positioning system for micro transfer printing,a novel 2-DOF monolithic rotation platform is designed.The platform is driven by two piezoelectric actuators,and can realize rotation decoupling by three flexible Hook's joints.Based on compliance the matrix method and the sensitivity analysis,the effects of the dimension parameters on the transmission ratio and the input stiffness are investigated,and the dominant parameters are determined.The performance test results show that the proposed rotation platform has good dynamic and static characteristics and the capability of 2-DOF rotation decoupling.This research improves the high precision positioning system of micro transfer printing and provides a hardware support for the research of micro transfer printing operation.In order to solve the problem that the above-mentioned rotation platform has a hysteresis error under high-frequency actuation,a novel Prandtl-Ishlinskii(P-I)inverse hysteresis model is developed by considering the dynamic characteristics of the system.The proposed hysteresis model is composed by a traditional inverse P-I hysteresis model and an inverse dynamic model which are connected in parallel.The parameters of the proposed inverse hysteresis model are identified based on the derivative-free optimization.Compared with the traditional P-I inverse hysteresis model,the proposed inverse hysteresis model has a higher modeling accuracy.Based on the feedback controller and the feedforward/feedback hybrid controller with hysteresis compensation,high precision rotation angle control and high frequency trajectory tracking are completed,and the compensation of hysteresis error under high-frequency actuation is realized.The structural form of the deterministic micro transfer printing system is studied,and a micro transfer printing system is set up.The transfer printing operations of micro/nano devices with different sizes,shapes and materials are realized by controlling the compression distance and the extraction velocity using the stamp with micro chamber.A novel flexible force sensor with 3D structure is designed and fabricated using micro transfer printing and micro origami technologies,which provides a hardware foundation for flexible wearable electronics research.