The Development of Ultra Small Electromagnetic Motor by Micromachining. 1st Report. Deposition Method of Thick Film with Low Residual Stress.

Abstract

Deposition method of thick film with low residual stress was investigated. The method controls residual stress by depositing compressive and tensile residual stress films in tum. Fundamental examinations were performed using plasma enhanced CVD in order to form thick SiO2 film as an insulation layer with low residual stress. The influence of RF power of plasma enhanced CVD on residual stress was examined, and changes in residual stress according to the progress of time after deposition was observed. As a result, it was clarified that the tensile residual stress changes after deposition, and the compressive residual stress film on the tensile stress film is necessary in order to get stable tensile residual stress. When the processing pressure is kept at 120 Pa, the residual stress is proportional to RF power and is controlled freely in tensile or compressive condition by adjusting RF power. The method also can correct the substrate bow, which occurs during the fabrication process of ultra small electromagnetic motor. It was demonstrated that the initial substrate bow of 12 μm was corrected to approximately 1 μm using this method.