| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a novel method and an apparatus available therefor, by which the precision or reproducibility of frequency characteristics is sufficiently secured and also a processing efficiency is improved when controlling the frequency of a piezoelectric element such as a surface acoustic wave element. <P>SOLUTION: In the first step of an etching process, a rough control step is carried out on the condition that an etching rate becomes comparatively high. In a rough control step Ts1, power to be supplied from a power circuit 18 to discharging electrodes 12 and 14 is increased. During such etching, a detector 17 measures the resonance frequency of a piezoelectric element 21 and sends output data to a controller 20. When the characteristic frequency reaches a prescribed value Fs, the rough control step Ts1 is ended and the controller 20 sends a switching control signal to the power source circuit 18 to lower the power to be supplied from the power source circuit 18, and to start a fine control step Ts2 for performing etching at the etching rate smaller than said rough control step. <P>COPYRIGHT: (C)2003,JPO</p> |
