Uniformalization of the AT cut quartz crystal wafer using maskless localized atmospheric pressure plasma etching process

摘要

We have newly developed the chemical finishing process to correct the thickness deviation of theAT cut quartz crystal wafer, which utilizes localized atmospheric pressure plasma. In the case of theatmospheric pressure plasma, high density plasma region is localized in the vicinity of the electrodebecause of its small mean free path. Removal volume is proportional to the dwelling time of theplasma on the workpiece surface. Therefore, free figuring without mask pattern is realized bynumerically controlled scanning of the localized reactive area. By applying our proposed correctingprocess, thickness deviation of the commercially available AT cut quartz wafer was improved from270nm to 40nm.