纳米压痕法测磁控溅射铝薄膜屈服应力  

Measuring Plastic Yield Stress of Magnetron Sputtered Aluminum Thin Film by Nanoindentation

作　　者：董健[1] 龙芝剑 孙笠[1] 蒋恒[1] 

机构地区：[1]浙江工业大学浙江省特种装备制造与先进加工技术教育部重点实验室,杭州310014

出　　处：《固体力学学报》2016年第3期273-279,共7页Chinese Journal of Solid Mechanics

基　　金：传感技术联合国家重点实验室基金(SKT1305);浙江省公益性技术应用研究项目(2016C34007)资助

摘　　要：为了在考虑残余应力下测量出磁控溅射铝薄膜的屈服应力,提出了一种实验测量方法,通过曲率测试法和球形压头纳米压痕法测出磁控溅射铝薄膜的屈服应力.建立球形压痕力学模型,并用ANSYS对球形压痕进行力学有限元仿真,利用直流磁控溅射技术在硅基上淀积一层1μm厚的铝薄膜,首先通过曲率测试法测量膜内等双轴残余应力,再利用最小二乘曲线拟合法从薄膜/基底系统的球形压头纳米压痕实验数据中提取出铝薄膜的屈服应力,测得磁控溅射铝薄膜的屈服应力为371±89 MPa.该方法也可以用来研究其他材料的薄膜和小体积材料的力学特性.Aluminum thin films have been widely used in MEMS devices, such as mechanical structures, wires, and poles of capacitors, knowing that their mechanical properties is crucial to the functional- ity and reliability of devices. However, the microstructural properties of materials in the form of thin films are proved to be quite different from those of the same materials in bulk form, which can lead to distinct mechanical behaviors. Typically, the yield stress and Young＇s modulus of a thin film are much larger than those of its bulk equivalent. Therefore, several methods have been used to measure the mechanical properties of films, e. g. wafer curvature method, depth-sensing nanoindentation, beam bending, bulge test, mi- crotensile testing and AC technique. Among these methods, the curvature method provides a convenient way to measure the residual stress of thin layers, and the nanoindentation technique is especially effective and convenient for the evaluation of mechanical behavior of thin films. Researchers have focused on the in- vestigation of thin metal layers by nanoindentation with the support of numerical methods, such as the fi- nite element method, dimension analysis and numerical optimization processes. Although the elastic modu- lus, yield stress and work-hardening exponent of film can be measured, these methods fail to take into ac- count the residual stress, which actually has a significant influence on the elastic-plastic properties of film. In this contribution, a simple experimental technique is presented for measuring the yield stress of magne- tron sputtered aluminum thin film by combining the curvature method and the sphere-tip nanoindentation technology. The mechanical model of spherical indentation is established; and the finite element simulations are conducted. The aluminum film with a thickness of approximately 1 μm is deposited on the silicon wafer substrate using a DC magnetron sputtering system. Both the curvature and nanoindentation tests are carried out in the Al film/Si substrate sys

关 键 词：屈服应力 曲率法 球形压头 纳米压痕 

分 类 号：O484.2[理学—固体物理]