Determining the Thin Film Mechanical Properties for CMOS Processes Using Micro Test Cantilevers

• Main Authors: Cheng, Chao-Lin, 鄭照霖
• Other Authors: Fang, Weileun
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/32136940976186595581

博士 === 國立清華大學 === 動力機械工程學系 === 104 === Standard process to develop MEMS device has gradually increased, especially exploiting CMOS process to implement MEMS device had been proposed. However, there is no complete mechanical properties database to provide designer in structural design. Therefore, in this study, expecting to establish an extraction methodology and mechanical properties database. This study employs an existing approach to determine the elastic modules, coefficient of thermal expansion (CTE), and residual stress of metal and dielectric films for standard CMOS processes. The test cantilevers with different stacking of metal and dielectric layers for standard CMOS process have been designed and implemented. Thus, the elastic modules, CTE, and residual stress of standard CMOS films can be respectively determined after the frequency responses, out-of-plane thermal deformations, and initial deformation of test cantilevers are measured. To demonstrate the feasibility of the present approach, thin films prepared by the Taiwan Semiconductor Manufacturing Company, Ltd. (TSMC) 0.35m 2P4M CMOS process were characterized. Eight test cantilevers with different stacking of CMOS layers and the auxiliary Si cantilever on SOI wafer are fabricated. The equivalent elastic modulus and CTE of CMOS thin films includes the metal and dielectric layers are respectively determined by the resonant frequency and static thermal deformation of test cantilevers. The residual stress of CMOS films are respectively determined by boundary rotation method and Timoshenko bi-layer theory. Moreover, cantilevers with different layer-stacking other than those of the test beams have been employed to verify the measured properties.