Fabrication And Characterization Of Micro Dielectric Barrier Discharge Reactor For Maskless Nanoscale Fabrication

In the field of semiconductor manufacturing and micro-electromechanical systems,plasma technology is an indispensable means of processing.In order to realize any maskless processing of any pattern,the research group proposed to use the inverted pyramid micro hollow cathode discharge array,to achieve high precision,high efficiency,maskless scanning processing.The devices use the electrode-insulating layer-electrode sandwich structure.Under the excitation of the DC electric field,the plasma and the electrode layer generated in the hollow micro-cathode of the inverted pyramid are in direct contact.Since the heavy ion counter electrode in the plasma layer of the physical bombardment effect and the thermal resistance effect,the micro-discharge electrode layer is easy to damage and make the whole device failure,micro-discharge life is difficult to improve.In order to solve the problem of short life of DC micro-hollow cathode discharger array.In this paper,we deposited a layer of silicon nitride film on the upper and lower metal electrodes of the micro-hollow cathode discharge array to protect the electrode layer,and it is effective in the form of AC-excited dielectric barrier discharge to prevent the glow discharge to the arc of the transition,reduce the thermal effect of the device damage,thereby improving the life of micro-discharge device for the follow-up maskless processing to lay a good foundation.Mainly contents of the dissertation are listed as follows:The 2D plasma simulation of the inverted pyramid dielectric barrier micro-discharger was carried out by using COMSOL software.The electron density distribution,the distribution of the potential density and the distribution of electron density under different medium conditions were obtained by simulation.The simulation provide theoretical basis for the choice of dielectric layer materials and the choice of working conditions.The processing of the device,mainly for the process of the following two problems,namely the lower electrode graphics success rate is low,and due to multi-layer film stress mismatch lead to SiNx dielectric layer crack analysis.For the first problem,this paper uses the thicker photoresist as the lower electrode wet etching pattern mask to protect the upper edge of the microcavity to achieve high success rate under the electrode pattern.For the second problem,The SiNx intrinsic stress required for the minimum residual stress and deformation of the device is obtained by multilayer film stress matching simulation.Then,the relationship between the process parameters such as RF power of plasma enhanced chemical vapor deposition,reaction gas flow ratio,air pressure and temperature and SiNx intrinsic stress and deposition rate was established experimentally,then the combination of process parameters corresponding to the target stress value was obtained.Under these parameters,the SiNx dielectric layer and micro-discharge device with good physical and chemical properties were successfully prepared.The influence of ballast resistor,air pressure and operating voltage on the electrical characteristics was studied,and the reason of the final failure of the device was analyzed.Which provides a basis for the subsequent selection of the device working parameters.