| 摘要 |
PURPOSE:To ensure the frequency control by removing the surface of the zinc oxide layer used as the piezoelectric substance by the dry etching and thus adjusting the thickness of the layer. CONSTITUTION:The vacuum degree within container 6 is set to 10<-10>-10<-3> torr, and the gas within container 6 is changed into the plasma via the high frequency sent from FR power source 9. And then the ion which is accelerated by the electric field caused near target 8 is put vertically to the surfaces of zinc oxide layers 3 and 5 of elastic surface wave element 12. In such way, the surfaces of layer 3 and 5 are removed gradually. In that case, if element 12 is made active previously, the frequency varies according to the thickness of layers 3 and 5 each. And this frequency change is monitored directly through frequency measuring instrument 13. Accordingly, the desired frequency is obtained by removing zinc oxide layer 5a while confirming instrument 13. As a result, the frequency dispersion can be exteremely reduced. |
