Fabrication Of 3D Microarray And Carbonization Via SU-8 Photoresist

With the development of Micro-Electro-Mechanical System(MEMS)technology,the demand of integrated on-chip power source components is increasing recently.Carbon-based micro-supercapacitors,as the most commonly used double-layer principle of MEMS supercapacitors,are provided with advantages of integration,small size,high charge and discharge efficiency,strong cycling performance,it is ideal for power supply of on-chip components.However,the micro-supercapacitors still have low energy density limitations now,in order to enhance the energy density of the supercapacitor,the electrode material of the supercapacitor is generally prepared by increasing the electrochemical properties of the electrode material itself and designing the 3D electrode structure.The SU-8 photoresist as the field of MEMS commonly is used in the design for the substrate structure,and it is generally used to prepare integrated thick film patterns that are vertical sidewalls and high aspect ratios.On the other hand,the SU-8 photoresist component contains a large number of carbocyclic structures,which are excellent precursors for preparing carbon electrode materials.In this work,porous carbon materials are prepared from carbonized SU-8 photoresist films,to explore the appropriate carbonization temperature and time,and doping and activation of the electrode material to improve the electrochemical performance,and designing to increase the specific surface area of 3D supercapacitor electrode structure.The main contents of this thesis include the following aspects:The main research contents of this dissertation is as follows:(1)A novel method is used to prepare thin film porous carbon,With the SU-8 photoresist as the precursor,the porous carbon material is prepared by carbonization in different maximum temperature,and the relative suitable carbonization temperature and time are selected by the electrochemical factors such as the capacitance,the impedance and the cycle performance.For the follow-up optimization work on SU-8 photoresist as a precursor to prepare on-chip supercapacitor lays the foundation.(2)Through the above conclusions and the basic preparation method,on this basis to improve the characteristics of the electrode material itself,the microelectrode materials are prepared by carbonized SU-8 photoresist doped magnesium citrate.The material is selected SU-8 photoresist as precursor,and different amounts of magnesium citrate powder mixed with in the SU-8 photoresist.The collective effect on gas from pyrolysis of magnesium citrate and pin carbon reaction produce a more abundant pore structure in the electrode material surface to increase the specific surface area of the electrode material,thereby increasing its capacitance,while the mesh pore structure can transfer electrolyte ions,and reduce the charge transfer resistance.(3)In order to further improve capacitance characteristics of electrode material by carbonization based on the SU-8 photoresist,the electrode material with some pores which cannot be used is prepared according to the above-mentioned method.We use potassium hydroxide(KOH)as the activator.To explore the best proportion of KOH activation,the pore size of carbon material which is the most appropriate electrolyte ion transport is controlled to in the nitrogen atmosphere at high temperature carbonation.Finally,the SU-8 photoresist doped with 30 mg/ml magnesium citrate is used as the precursor,and the mass ratio of activator(KOH)is 1:2.The electrochemical activity of the material is improved at different levels.(4)The above experiment explores the preparation of high-performance electrode materials,then we focus on the electrode structure,it is the target by increasing the specific surface area to increase energy density of the electrode.we design an "X" type 3D-microarray structure for stacking SU-8 photoresist by oblique lithography.In order to prepare a stable "X" type microarray,we first study the best microarray arrangement by theoretical model analysis,and explore the best process to solve the lithography process problems such as the distortion and collapse of microarrays and the blocking and adhesion in the microholes.