| 摘要 |
PURPOSE: To obtain an angular velocity sensor in which a resonance frequency in a moving part can be adjusted and to adjust the resonance frequency by etching and shaving any one of protective films by a method wherein the cross section of a support beam in the moving part is formed to be a quadrangle and the protective films against an etching operation are formed on either or both of the surface and the rear surface and both side faces of the support beam. CONSTITUTION: A support-beam part 12 is formed as a support beam 13 whose cross section is rectangular and which is made of polysilicon. Silicon nitride films 14 are formed on the surface and the rear surface, and silicon oxide films 15 are formed on both side faces. The protective films 14, 15 differ in their etching characteristic. In order to adjust a resonance frequency after the support beam has been manufactured, a resonance frequency in the horizontal direction B1, B2 and that in the vertical direction C1, C2 are measured and compared, and the direction in which the resonance frequecny is high is selected as an object to be adjusted. For example, when the resonace frequency in the vertical direction (detection mode) is high, the silicon nitride films 14 are shaved by CF4 /O2 /N2 mixed gas. The mixed gas does not affect the silicon oxide films 15. When the resonance frequency in the horizontal direction (vibration mode) is large, the silicon oxide films 15 are ground by CHF3 gas. |
