基于屈曲脱粘的纳米薄膜力学及界面性能研究

发布时间：2018-04-05 13:48

本文选题：薄膜/基底结构　切入点：屈曲脱粘　出处：《天津大学》2014年硕士论文

【摘要】：薄膜/基底结构有效地实现了系统微型化和信息化,被广泛地应用在微电子、航天、生物、医学等领域。在外载的作用下,膜/基结构在工作过程中会出现薄膜断裂、屈曲、脱粘等失效模式。膜/基结构界面的破坏,会极大地影响结构的在役性能。本文将结合实验与数值分析,基于屈曲脱粘对基底上沉积的纳米薄膜的力学性能及界面性能进行研究。原位观察了薄膜/有机玻璃基底结构在单轴压缩加载下薄膜表面直线型屈曲的生成和扩展过程,采用屈曲扩展理论对实验现象进行研究。在卸载过程中,观察到了直线型屈曲模式转化为电话线型屈曲,后转化为泡状屈曲。研究结果表明:直线型屈曲失稳及模式转化与薄膜残余应力、薄膜应力释放、薄膜和基底泊松比等因素相关。采用纳米压痕法研究了界面影响下泡状屈曲的力学性能。通过对泡状屈曲的原子力扫描结果与压痕结果进行对比分析,实现对泡状屈曲高度的测量。对300nm和400nm厚度薄膜,测量和研究了泡状结构的弹性模量及刚度。研究表明:泡状屈曲刚度随高度的增加减小,随厚度的增加而增加。界面的作用使得薄膜/基底结构的弹性模量测试值更大,结构刚度、承载效果更强。薄膜/基底结构的界面粘接能是薄膜器件最重要的性能参数之一。本文基于界面对膜/基结构的影响,提出了表征界面性能的理论模型。采用压痕法分别在脱粘区域和粘接良好区域进行压痕。基于宏观力学能量法,利用两个区域等位移的塑性功差值来确定界面能量释放率。根据硬度/弹性模量随压痕位移的变化情况,来确定脱粘临界位移。采用内聚力模型来描述薄膜基底间的粘接关系,通过有限元方法来模拟薄膜的屈曲脱粘及扩展过程。研究界面参数对界面破坏行为的影响。通过对比实验和模拟中的界面脱粘长度及压痕曲线对实验测得的界面性能参数进行验证、完善。
[Abstract]:The thin film / substrate structure has been widely used in the fields of microelectronics, spaceflight, biology, medicine and so on.Failure modes such as film fracture buckling and debonding will occur in the working process of the membrane / base structure under the action of external loading.The destruction of the membrane / substrate interface will greatly affect the in-service performance of the structure.In this paper, the mechanical properties and interfacial properties of nanocrystalline films deposited on substrates are studied based on buckling debonding and numerical analysis.In situ the formation and propagation of linear buckling of thin film / plexiglass substrate structure under uniaxial compression loading were observed. The experimental phenomena were studied by buckling propagation theory.During the unloading process, the linear buckling mode was observed to be transformed into telephone line buckling mode and later to bubble buckling mode.The results show that the linear buckling instability and mode transformation are related to the residual stress of the film, the release of the film stress, the Poisson's ratio of the film to the substrate, and so on.The mechanical properties of bubble buckling under the influence of interface were studied by nano indentation method.The height of bubble buckling is measured by comparing the results of atomic force scanning and indentation.The elastic modulus and stiffness of 300nm and 400nm thin films were measured and studied.The results show that the bubble buckling stiffness decreases with the increase of height and increases with the increase of thickness.The effect of interface makes the measured value of elastic modulus of thin film / substrate structure larger, the structure stiffness and bearing effect stronger.The interface bonding energy of thin film / substrate structure is one of the most important performance parameters of thin film device.Based on the influence of the interface on the structure of the film / substrate, a theoretical model is proposed to characterize the properties of the interface.Indentation method was used to indentation in debonding area and good bonding area respectively.Based on the macroscopic mechanical energy method, the plastic work difference between the two regions is used to determine the energy release rate of the interface.According to the change of hardness / elastic modulus with indentation displacement, the critical displacement of debonding is determined.The cohesive force model is used to describe the adhesion relationship between the film substrates and the buckling debonding and propagation process are simulated by finite element method.The influence of interface parameters on interface failure behavior is studied.The interface performance parameters are verified by comparing the interfacial debonding length and indentation curve in the experiment and simulation.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：O484.2

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