用于无掩膜加工的介质阻挡微放电器阵列的制作及性能表征

发布时间：2018-06-15 10:31

本文选题：介质阻挡微放电 + 氮化硅　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：在半导体制造和微机电系统领域,等离子体技术是一种不可或缺的加工手段。为了实现任意图形的无掩膜加工,课题组之前提出利用倒金字塔微空心阴极放电器阵列,来实现对样品高精度、高效率的无掩膜扫描加工。该微放电器阵列采用的是电极-绝缘层-电极的三明治结构,在直流电场的激励下,倒金字塔空心微阴极内产生的等离子体和电极层直接接触,由于等离子体中的重离子对电极层的物理轰击作用以及热阻效应,微放电器的电极层很容易损坏而使整个器件失效,微放电器的寿命很难得以提高。为了解决直流微空心阴极放电器阵列寿命短的问题,本文通过在微空心阴极放电器阵列的上下金属电极上沉积一层氮化硅膜以保护电极层,采用交流激励的介质阻挡放电形式,有效阻止辉光放电向弧光的转变,减小热效应对器件的破坏,进而提高微放电器器的寿命,为后续无掩膜加工奠定良好的基础。论文的主要内容如下:采用COMSOL对所设计的倒金字塔介质阻挡微放电器进行二维等离子体仿真,通过仿真研究,得到了倒金字塔内电子密度分布、电势分布以及不同介质条件下的电子密度分布规律,从而为器件的介质层材料选择和工作条件的选择提供理论依据。器件的加工制备方面,主要针对工艺过程以下两个难题,即下电极图形化成功率低,以及因多层膜应力不匹配导致SiN.x介质层出现裂纹进行分析解决。针对第一个问题,本文采用较厚的光刻胶作为下电极湿法刻蚀图形化掩膜保护住微腔上边缘实现高成功率下电极图形化。针对第二个问题,本文通过多层膜应力匹配仿真得到器件残余应力和变形最小时所需的SiNx本征应力,然后建立PECVD射频功率、反应气体流量比、气压、温度等工艺参数与SiNx本征应力和沉积速率的关系,得到目标应力值对应的工艺参数组合,在此参数下成功制备物理化学性能良好的SiNx介质层,并最终制备得到质量良好的介质阻挡微放电器阵列。器件电学性能表征方面,研究了限流电阻、工作气压、工作电压等参数对放电时电学特性的影响,分析了器件最终失效的原因。为后续无掩膜加工时的介质阻挡微放电的工作参数选择提供实验依据。
[Abstract]:Plasma technology is an indispensable processing tool in semiconductor manufacturing and micro-electromechanical systems. In order to realize the unmasked machining of arbitrary graphics, we proposed to use the inverted pyramid microhollow cathode array to realize the high precision and high efficiency non-mask scanning processing of the samples. The array adopts sandwich structure of electrode, insulation layer and electrode. Under the excitation of DC field, the plasma produced in the hollow microcathode of the inverted pyramid is in direct contact with the electrode layer. Due to the physical bombardment and thermal resistance of heavy ions on the electrode layer in plasma, the electrode layer of microdischarger is easily damaged, which makes the whole device fail, and the lifetime of microdischarge apparatus is difficult to be improved. In order to solve the problem of short life of DC micro hollow cathode discharger array, a layer of silicon nitride film was deposited on the upper and lower metal electrode of the micro hollow cathode discharge array to protect the electrode layer, and the form of dielectric barrier discharge was adopted. It can effectively prevent the change from glow discharge to arc, reduce the thermal damage to the device, and then improve the life of the microcharger, and lay a good foundation for the subsequent processing without mask. The main contents of the thesis are as follows: the electron density distribution in the inverted pyramid is obtained by using COMSOL to simulate the two-dimensional plasma of the inverted pyramid dielectric barrier microamplifier. The potential distribution and electron density distribution under different dielectric conditions provide theoretical basis for the selection of dielectric layer materials and working conditions of the devices. In the fabrication of the devices, the following two problems are discussed, namely, the low success rate of the lower electrode graphics and the analysis and solution of the cracks in the SiN.x dielectric layer caused by the mismatch of the stress of the multilayer film. In order to solve the first problem, the thick photoresist is used as the lower electrode wet etching graphical mask to protect the upper edge of the microcavity to realize the high success rate of electrode graphics. Aiming at the second problem, the residual stress and the intrinsic stress of SiNx are obtained by multi-layer stress matching simulation. Then the radio frequency power of PECVD, the ratio of reaction gas flow and the pressure are established. The relationship between temperature and Sinx intrinsic stress and deposition rate, the combination of process parameters corresponding to the target stress value was obtained, and the SiNx dielectric layer with good physical and chemical properties was successfully prepared under these parameters. Finally, a high quality dielectric barrier microamplifier array was prepared. In the aspect of electrical performance characterization, the influence of current limiting resistance, working pressure and working voltage on the electrical characteristics during discharge is studied, and the reasons for the ultimate failure of the device are analyzed. The experimental basis is provided for the selection of working parameters of dielectric barrier microdischarge in non-mask machining.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O461.2

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