Study On The Through-Via Inter Connection Structure And Process Design For The Flexible Substrates

With the increase of people's attention to their health,the market demand for electronic products that can monitor the status of human body in real time also continues to increase,which makes the research and application of flexible electronic technology develop rapidly.Electrical interconnection and packaging of flexible electronics is an indispensable part of flexible electronics.At present,the methods used in flexible electronic packaging and electrical interconnection mainly include hard film buckling structure,island-bridge structure,flip chip and CIF packaging with COF.All of these methods belong to two-dimensional packaging methods,which are difficult to be combined with the three-dimensional structure of electronic devices,and also lead to an increase in the size of flexible electronic systems after packaging.Based on the limitations and deficiencies in flexible electronic packaging,this paper proposes through-via inter connection structure for three-dimensional packaging and interconnection of flexible electronics,and finishes the fabrication and optimization of through-via inter connection structure.The specific work is as follows:?1?In this paper,the development and prospect of flexible electronics at domestic and abroad are introduced,and the current research status and problems of packaging and electrical interconnection technology in flexible electronics are systematically studied.After that,the main research contents of this paper are put forward.?2?In this paper,the properties of flexible materials which have been used in flexible electronics are analyzed.Polydimethylsiloxane?PDMS?is chosen as the flexible connecting layer material,and orthogonal experiments are carried out.The optimum curing parameters are obtained as follows:mass ratio of main agent to curing agent is8:1,curing temperature is 110?,curing time is 3 h.Nano-Nano-silica?SiO₂?is prepared,then nano-silica is used to modify PDMS material.The hardness of PDMS/SiO₂ was increased to 85.51 HA,which was 54.6%higher than that of PDMS.The flexible material meeting the hardness requirement is obtained at last.?3?The structure and key dimensions of through-via inter connection structure are designed and explained.The processing routes of through-via inter connection structure are proposed in this paper.Then through-via inter connection structure is fabricated and optimized by Micro-Electro-Mechanical System technologies with the specific process parameters.?4?With reference to the electrical theoretical knowledge of the through-silicon via lead structure,the theory analysis and electrical tests with the structure are finished and the result shows that the resistance,parasitic inductance and parasitic capacitance of the structure are not obvious.And by testing the resistance of graphene with through-via inter connection structure under different curvature radius,the flexibility and electrical interconnection stability of through-via inter connection structure are demonstrated,and the feasibility of the structure for flexible electronics is proved.