Study Of Multi-parameters Determination Of Mechanical And Interfacial Properties Of Interconnection Film By SAW

With the further rise of 5G,automotive electronics,AI,Io T and other downstream application fields,integrated circuit is still developing vigorously.The interconnection of integrated circuits(IC)is a focus job.The application of low-k thin films can alleviate some problems such as RC delay,cross-talk,and power consumption in IC interconnection.However,low dielectric constant(low-k)material has problems on poor mechanical characteristics,poor interface characteristics,thermal instability.Moreover low-k films are not suitable for traditional detection methods due to the soft and easy falling off of low-k materials.It is urgent to develop a non-destructive online measurement method for the detection of low-k films.In this dissertation,nondestructive and on-line measurement methods for mechanical and interfacial properties of thin films with low-k used in the Cu/low-k interconnection of integrated circuits are studied.First,the cohesive zone model(CZM)is introduced in the SAW technology in this dissertation.The key parameters which can be characterized the interfacial adhesion are determined to perform the nondestructive,quantitative and on-line test of the interfacial adhesion of the film/substrate structure.Secondly,this dissertation proposes a set of criterion to judge the interfacial adhesion based on the CZM-SAW technology,which can not only measure the adhesion but also judge the interfacial adhesion of film/substrate structure nondestructively,quantitatively and systematically.Furthermore,by including the measurement error of film parameters into the standard value of adhesion,error of adhesion measurement about 5% which is introduced by other film parameters is corrected.Further,considering the mutual influence of the interface adhesion and film Young's modulus in measurement,a simultaneous measurement method for Young's modulu and adhesion is proposed in this dissertation.In one hand,the simultaneous measurement method for the two parameters improves the reliability of the results of the SAW technology.On the other hand,it broadens the application range of the SAW technology.Among the experimental samples measured in this dissertation,the highest accuracy of Young's modulus measurement after adopt the two-paprameter simultaneous measuring method can reach 30.74%.For experiments,firstly,in terms of measurement system,for the LSAW experimental system used in this dissertation,many key factors are studied including:the absorptivity of laser for different samples,the influence of laser pulse width,the width of the focused laser line,film thickness on the SAW signals,and the choice of the crystal orientation in expriments.Through these studies,some guidances are put forward for the practical application of the laser generated ultrasonic surface wave(LSAW)experimental system.Based on that,all the nondestructive testing methods based on the SAW technology proposed in this dissertation have been applied on the test of different low-k test samples by LSAW experimental system.The detection accuracy of adhesion is 0.1 PPa/m,and for Young's modulus is 0.01 GPa.The comparative tests are tested by different measurement methods such as Nano-scratch.The results verify the feasibility and correctness of the proposed SAW technology.