MANUFACTURE OF SURFACE WAVE FILTER

摘要

PURPOSE:To attain stable quality by forming a counter electrode for check on a wafer at forming of a comb-line electrode and forming the comb-line electrode for check at the position of the opposite electrode for check at the forming of the opposite electrode so as to estimate the frequency characteristic thereby reducing the defect generating rate. CONSTITUTION:An aluminum 2 is vapor-deposited on the entire face of a glass substrate 1 and most of the wafer is etched as shown in Fig. (a) so as to form the comb-line electrode 3 and the opposite electrode is formed only to one part as shown in Fig. (b). A piezoelectric body 4 is attached to the entire face on it by sputtering and the aluminum 5 is attached to the entire face of it by vapor- deposition. Then most of the wafer is etched as shown in Fig. (c) so as to form the electrode 6 and the electrode 3 is formed to a part where the electrode 6 is formed before. Thus, the part formed with the electrode 3 for check is exposed with a pad electrode 7 and the frequency characteristic of the other part of all the wafer is estimated by checking the frequency characteristic of one part while using the electrode 7.