Theoretical Study On Synchronous Test Technique For Mechanical Properties Of Film/Substrate System With Residual Stress

Thin film and film/substrate structure is widely used in many advanced techniques,such as mechanics,civil engineering and biotechnology.Furthermore,it also exist in our daily life,such as wall and its whitewash,adhesive tape and its substrate,roof and its waterproof layer,all of that can be seen as the film/substrate structure.Thus,the research of structural stability,reliability and durability need a better understanding to the mechanical behavior of the film/substrate structure,therefore it is necessary to characterize the young's elastic modulus,residual stress,poisson's ratio of the thin film and characterize the adhesion strength of film/substrate interface.Existing test theories usually doesn't consider the residual stress and usually require prior assuming the poisson's ratio(or young's modulus)of the film as a known parameter,then they give some methods to determine the other parameters.The use of precious test data(such as poisson's ratio)for this experiment is error,and the error will impact the measurement of the young's elastic modulus,the residual stress and the adhesion strength of film/substrate interface in this experiments.So,in our early work,the conception of “synchronous test technique” was presented,and the synchronous test method of film/substrate without residual stress was given.However,as we all know,temperature,humidity,etching method,processing conditions and manufacturing process of film/substrate system,are likely to cause the residual stress of thin film.So,this paper consider the effect of residual stress,and committed to acquire the young's elastic modulus,residual stress,poisson's ratio of the thin film and the adhesion strength of film/substrate interface at the same time through a test data analysis of an experimental sample.This paper mainly consists by the following seven chapters:The first chapter mainly introduced the problem introduction and the research significance and elaborated the research status both here and abroad,the main research objective,research content and innovation.The second chapter mainly introduced some basic theory of thin plate problem in elastic mechanics,which is needed for this paper's research.The third chapter introduced the existing test method for mechanical properties of film/ substrate system.The fourth chapter mainly solved two membrane problems,which is the problem of axisymmetric deformation of circular membrane and annular membrane with residual stress under axial loading.Moreover,the process of establishing equations and the detailed solving process of thin film equation was presented,and a concrete numerical examples were given.The fifth chapter put forward two new synchronous test techniques for mechanical properties of film/substrate system with residual stress,these techniques can obtain the young's elastic modulus,residual stress,poisson's ratio of the thin film and the adhesion strength of film/substrate interface at the same time by the analysis of one experimental data.The sixth chapter compared the measuring method in this paper with the existing test method,and analyzed the advantage of the measuring method presented in this paper.The seventh chapter summarized the main research results,the main innovations and prospected the future research direction.In this paper,it's the first time to put forward the synchronous test technique which consider the effect of residual stress,and extend this technique to a more commonly situation.Through the analysis of one test data,the technique can get the surface properties of the thin film(elastic modulus,residual stress and poisson's ratio)and the film/substrate interfacial properties(adhesion strength)at the same time.This is the main innovation of this paper.The research of this paper has great value and significance to check the correctness of the existing test method and to carry out the following research.