基于SAW-IDT无损表征互连薄膜杨氏模量的研究  

Non-destructive Characterization for Young's Modulus of Interconnection Thin Films by SAW-IDT

作　　者：黄祎婷 肖夏 张立 HUANG Yiting;XIAO Xia;ZHANG Li(School of Microelectronics,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学微电子学院,天津300072

出　　处：《传感技术学报》2024年第11期1841-1848,共8页Chinese Journal of Sensors and Actuators

基　　金：国家自然科学基金项目(61571319)。

摘　　要：探究了一种利用声表面波叉指换能器(SAW-IDT)无损表征low-k互连薄膜杨氏模量的方案。采用有限元法对不同工作频率的SAW-IDT进行建模,研究SAW-IDT所激励的声表面波在不同厚度的二氧化硅薄膜以及low-k薄膜表面传播的特性。利用倾斜叠加法计算声表面波在薄膜表面传播的频散曲线并与理论频散曲线匹配,对不同厚度的二氧化硅薄膜和low-k薄膜的杨氏模量进行了表征。仿真结果表明,厚度为500 nm和1000 nm的二氧化硅薄膜杨氏模量的反演结果与实际值的误差为4.28%和2.50%,厚度为500 nm和1000 nm的low-k薄膜样片的杨氏模量测量误差分别为6.95%和4.53%。基于仿真结果设计了频率范围为20 MHz~125 MHz的线性周期结构的SAW-IDT,并表征了厚度为1000 nm的low-k薄膜的杨氏模量,为互连薄膜杨氏模量的无损检测提供了一种有价值的方案。Based on the technique of surface acoustic wave(SAW)non-destructive testing(NDT),a scheme for measuring the Young's modulus of thin films by surface acoustic wave-interdigital transducer(SAW-IDT)is studied.By designing SAW-IDTs with finite element method,the dispersion curves of SAW propagating on the thin films are obtained for the characterization of the Young's modulus.The propagation characteristics of SAW excited by SAW-IDT on the surface of SiO2 and low-k films are simulated,and the SAW dispersion curve is calculated by using slant stack method.The Young's modulus of the SiO2 and low-k thin films are characterized by matching with the theoretical dispersion curve.The results show that the Young's modulus measurement errors between the simulation results and the actual values of the SiO2 films with thicknesses of 500 nm and 1000 nm are 4.28%and 2.50%,respectively,and the errors of the low-k films with thicknesses of 500 nm and 1000 nm are 6.95%and 4.53%,respectively.Based on the simulation results,SAW-IDT with linear periodic structure with a frequency range of 20 MHz-125 MHz is designed,and Young's modulus of the low-k film with thickness of 1000 nm is characterized,which provides a valuable scheme for the non-destructive testing of Young's modulus of interconnection films.

关 键 词：声表面波技术 杨氏模量 无损检测 有限元 叉指换能器 

分 类 号：TN405.97[电子电信—微电子学与固体电子学]