Effect of die attachment on key dynamical parameters of micromachined gyroscopes

This paper presents the effect of die attachment on the resonant frequency and quality factor of micromachined gyroscopes. Two types of epoxy die attachments are adopted in micromachined gyroscopes. A fourth order mass-spring-damper system is proposed to augment the dynamics of micromachined gyroscopes. Frequency response tests are implemented to analyze the quality factor and resonant frequency. Both maximums of the resonant frequency and quality factor are obviously much larger in the drive mode and sense mode when the more rigid die attachment is applied, due to the fact that rigid die attachment can minimize the energy loss through die substrate. Furthermore, the temperature dependence of the quality factor and resonant frequency on the die attachment is experimentally studied over the range −40°C to 60°C. Based on the experimental study, the rigidity, viscosity and temperature characteristics are the most considerable parameters for the die attachment in micromachined vibratory gyroscopes. Besides, the type of the mode shape is another factor determining the quality factor and temperature coefficient of resonant frequency. Balanced anti-phase mode operation can suppress the effect of die attachment.