【作者】 姜理利；

【导师】 唐洁影；

【作者基本信息】 东南大学 ， 微电子学与固体电子学， 2006， 硕士

【摘要】 随着人们对MEMS产品的深入研究和开发,越来越多的MEMS产品即将走进日常生活中,而可靠性问题作为MEMS产品商品化过程中的必然要求,引起了越来越多的重视和研究兴趣。但研究MEMS器件可靠性的理论并不多,所以有必要从理论上分析MEMS可靠性并建立数学模型,为MEMS的设计提供参考依据。MEMS器件在工作的时候会受到静电力或其它的静态载荷,同时器件会处于各种不同的环境中,在运输和使用的过程中将会受到不同程度的冲击和碰撞,另外应用在航空航天及军事系统上的MEMS器件必须能够承受一定强度的冲击,在冲击作用下,MEMS器件可能会发生断裂、分层和粘附等。表面加工微悬臂梁作为MEMS器件的基本结构,可以用于RF开关、光开关、谐振器、传感器等。本文以表面加工多晶硅微悬臂梁为例在静态载荷、动态载荷两种情况下分析了MEMS器件的可靠性,分别对它建立了断裂失效的可靠性模型。在静态载荷的分析中,考虑MEMS加工工艺的特殊性采用数学模型法建立了威布尔模型;同时利用物理原因法建立了应力-强度干涉模型。在动态载荷的分析中,将微悬臂梁看作一个质量分布参数系统,运用模态叠加法计算出微悬臂梁在冲击下的位移响应和应力分布,根据器件本身、工艺条件和使用环境,确定器件的许用强度。根据应力和强度的不确定性分别给出分布密度函数,运用应力-强度干涉理论建立了可靠性模型来定量地计算微悬臂梁在冲击下断裂失效的可靠度。最后在理论分析的基础上,进行了冲击实验,讨论了实验结果并利用实验数据对理论模型进行了一定的修正。这为微悬臂梁的强度可靠性设计和分析提供了理论依据,可以进一步优化设计。更多还原

【Abstract】 In recent years, enormous progress has been made in developing and designing new MEMS products. More and more products are coming in the market. The reliability of MEMS is becoming very important. It is necessary to identify the mechanisms of failure and develop the mathematical models for such mechanisms, so as to use these models to improve the reliability design for MEMS.The MEMS devices are loaded by static force when they are under the operation. Dynamic loads provided by the environment will affect them during transportation or operation. Especially, MEMS used in automotive and space applications will experience dynamic shocks during deployment and operation. Under shock loads, MEMS devices may fail in different models including fracture, stiction, and delamination. This paper focus on the reliability of the micro-cantilever subjected to both static and dynamic loads considering the failure of fracture.In the static analysis, Weibull model and stress and strength model are founded. In the dynamic analysis, the micro-cantilever was taken as a distributed-parameter system. The displacements and stresses of micro-cantilever are then formulated with the mode superposition method. Whether the cantilever failed due to fracture or not could be determined by the maximum stress. This method can be also used in other complicated MEMS structures and devices. Using interference theory of stress and strength in the mechanical field, the reliability model will be presented and it can predict the probability of the reliability of the cantilever under shock loads. It will help improve the design of MEMS.At last, the shock experiment is done based on the analysis and the theory model is modified by the data from the experiment. All those play an important role in the design and analysis of the reliability of MEMS.更多还原