Flexible Heterogeneous Integration Of High-density Micro-coil And Application In MEMS Energy Harvesters

Along with the rapid development of MEMS energy,flexible electronic and other fields,a phenomenon has been established that various electronic devices are gradually developing towards miniaturization,flexibility,and integration.It has great research significance of MEMS energy harvesters provides power for sensor networks,robots,wireless communication systems and other portable electronic devices.Wearable devices and flexible devices have received widespread attention in recent years.Therefore,researchers began working on the preparation of flexible electronic products using various technologies and processes.At present,the electromagnetic energy harvester is the most efficient provide power method in the micro-energy harvesting technology,but this method has the problem of relatively low output voltage.An effective solution measure is to achieve a substantial increase in output voltage by increasing the number of coil turn.However,the coil prepared on a rigid substrate lacks the ability of conformal assembly,which makes it impossible to apply it in a small space or in a micro device.Therefore,the present of the high-density micro-coil flexible heterogeneous integration method is particularly important,and this method is of great significance for the high-performance output of microelectromechanical systems(MEMS)electromagnetic micro energy harvesting devices and the development of flexible electronics.This paper innovatively proposes an idea of using electroplated copper to prepare coils on rigid substrates and transfer them to PET substrates by electroplating nickel to achieve the heterogeneous integration of MEMS high-density micro-coils.In the preparation process,technologies such as micromachining and electrochemical processes are needed.High-density flexible micro-coils are prepared by micromachining technology and electrochemical machining technology.In order to achieve high-quality flexible heterogeneous integration of coils prepared on a rigid substrate,theoretical analysis and calculations are required before the experiment starts.For the "substrate-film" material system,a theoretical model is established.In order to qualitatively analyze and compare the energy releasing rate of substrate splitting and interface splitting under steady-state conditions,so as to predict the best propagation path of cracks,we introduced a certain thickness of silicon dioxide on the silicon wafer to peel off the coil with excellent characteristics.After the coil is peeled off,the flexible substrate PET is bonded with the high-density micro-coil peeled off from the rigid substrate.In order to characterize the output voltage,output power and other operating characteristics of the coil,a test platform was built to perform energy harvesting test and analysis on the device.The test results show that the output voltage of the double-layer high-density micro-coil is 3 V,and the device has potential applications in flexible electronics.