π网络法测试石英晶片方法及系统设计

The research and system design of measuring quartz crystal wafer in a π-network

石英晶片电参数决定了其产品质量优劣 ,因此在石英晶片生产加工过程中精确测试其电参数尤为重要。符合国际标准的π网络法石英晶片测试系统由单片机、直接数字频率合成器及电压检测单元等组成。系统可测试 1MHz～ 6 0MHz的石英晶片谐振频率 ,具有较高的重复精度 。

Quality of quartz crystal wafer is determined by its electrical parameters, so it is of great importance to measure its parameters accurately in the process of manufacture. The technologic method is based on measuring the frequency of quartz crystal wafer in a π network in accordance with IEC (International Electrotechnical Commission). The measuring system is mainly composed of a Single Chip Microcomputer, the direct digital synthesize chip and the voltage testing unit, which can distinguish resonance frequency of the quartz crystal wafer from 1 MHz to 60 MHz. The performance of the system is better than that of the oscillatory system and of the impedance system, which are widely used in China. Measuring results possess good repetitive precision.