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The aim of this work is to reduce the residual stress in cured SU-8 Photoresist layer by vibration stress relief (VSR) method. The vibration device was designed according to the results of the ANSYS modal simulation, which was used for the thin film VSR. Meanwhile, some important influencing factors, such as the excitation current and the vibration time, have been discussed. The residual stress in the SU-8 layer was measured by profile method, and the values of residual stresses in the SU-8 layer before and after VSR were compared. The experimental results show that residual stress in SU-8 layer can be effectively eliminated or homogenized by VSR if the proper vibration parameters were chosen in the experiment.

The purpose of this work is to study the mechanical characteristics of the silicon nitride(SiNx) thin films prepared by PECVD technique, some researches as follows were carried out. First, the SiNx thin films were deposited on the two different substrates. Then, the atomic force microscope (AFM) was adopted to test the surface quality of the SiNxfilms, and the scanning electron microscope (SEM) was used to test the section morphology of the SiNxthin films. Finally, the rotating beam structures was applied to measure the residual stress in the SiNx films. The SiNxthin films with low stress can be fabricated through PECVD, in which the surface roughness values(Ra) are 1.261 nm and 2.383nm, and the residual stress is 43.5 kPa. Therefore, the SiNxthin films deposited by PECVD are suitable for the preparation of device dielectric films in MEMS.