Fabrication And Characteristics Of Flexible Radio-frequency Inductors And Interconnects

In recent years,high-speed flexible electronic gradually attracted people’s attention.Especially with the development of the wearable equipment and biomedical,more and more scientific research institutions have put into the flexible electronic research.Compared with traditional hard electron,flexible electron has many distinct characteristics,such as light-weight,bendability and collapsible,mechanical stability and low cost.With the development of high-speed flexible thin-film devices,many milestone devices such as flexible microwave PIN diodes,flexible thin-film transistors(TFTs)and flexible RF switching circuits have been developed and well performed at high-frequency field,which indicates the prospect of flexible monolithic microwave integrated circuits based on plastic substrates.However,high-performance flexible passive components such as inductors and interconnect lines are indispensable for high-speed flexible integrated circuits and systems.It is also essential to study the RF characteristics of the passive components.Firstly,the materials needed for fabrication of flexible electronic devices are introduced,including flexible substrates,conductive materials,insulating materials and flexible electronic semiconductors.As functional layers of flexible electrons,the single-crystal nanomaterials have many advantages such as high carrier mobility and the mature production process.The process of thin film transfer and the problems possibly occurring during the process of transfer are described in detail.The method is simple,convenient and is compatible with the current mainstream semiconductor manufacturing process.Then we introduce the complete process of flexible inductor from design to fabrication and finally simulation.Firstly,with the design scheme of the flexible inductor determined,the design scheme is transformed into the GDSII layout files by CleWin layout design software,and then the layout files is made into a mask.The layout consists of three layers including M1 layer,Via layer and M2 layer.The flexible inductors are made by using the homogenizer,lithography machine and e-beam evaporation metal deposition equipment.And finally simulation are performed through the HFSS to analysis and optimize the various parameters of the flexible inductor.Finally,the fabrication process and RF characteristics of the flexible interconnects are analyzed.This paper introduces a series of processes of the interconnects,such as layout design,fabrication process and simulation.The influence of line width,line length and different substrate on loss characteristics is also studied.It is shown that the minimum CPW loss of the interconnects achieved with the wider line width,the shorter line length and PET / SU-8 substrate structure.The paper provides a useful guide for high-speed interconnects in monolithic flexible integrated circuits.