石英音叉微细加工若干问题探讨

采用基于半导体工艺的光刻、化学腐蚀等微细加工方法在石英晶体基片上批量制作石英音叉。化学腐蚀石英音叉时，叉指的一个侧面中央有棱角，腐蚀速率先慢后快有利于棱角的消除，但去掉棱角的主要方法是增加腐蚀时问；实验探索了能够耐受长时问腐蚀液浸泡的Cr／Au掩模的制作方法和工艺，成功地腐蚀出石英音叉样品；选用黑白反相的十字套准标记进行石英音叉图形的双面光刻套准可以减小人为对准误差，腐蚀出的双面音叉图形的套准精度可小于3μm。石英晶体结构的三角对称性和Cr／Au掩模的耐腐蚀性是限制微细加工制作石英音叉达到理想形状的关键。     

Drive Signal Frequency-Lock Method Based on 90° Phase Shift for Quartz Angular-Rate Sensor

A drive signal frequency-lock method for quartz angular-rate sensor is presented. The calculation result obtained by the equivalent volume force analytic method indicated that when taking the inherent frequency of the drive tines as the drive signal frequency the phase of the reference vibration is 90° behind that of the drive signal, and the square of amplitude is less than that of the maximal amplitude by 1/(4Q~2_d) merely. The curves derived from the finite element analytic method proved that near the inherent frequency the phase shift of the feedback voltage is identical to that of the reference vibration, and the amplitude is proportional to that of the reference vibration, and the phase shift is linear approximatively with the frequency shift. The frequency shift could be calculated according to the phase shift obtained by quadrature correlation detection, so the drive signal frequency could be locked at the inherent frequency of the drive tines by means of iteration.     

Drive Signal Frequency-Lock Method Based on 90° Phase Shift for Quartz Angular-Rate Sensor

A drive signal frequency-lock method for quartz angular-rate sensor is presented. The calculation result obtained by the equivalent volume force analytic method indicated that when taking the inherent frequency of the drive tines as the drive signal frequency the phase of the reference vibration is 90° behind that of the drive signal, and the square of amplitude is less than that of the maximal amplitude by 1/（4Q²_d） merely. The curves derived from the finite element analytic method proved that near the inherent frequency the phase shift of the feedback voltage is identical to that of the reference vibration, and the amplitude is proportional to that of the reference vibration, and the phase shift is linear approximatively with the frequency shift. The frequency shift could be calculated according to the phase shift obtained by quadrature correlation detection, so the drive signal frequency could be locked at the inherent frequency of the drive tines by means of iteration.