| 摘要 |
PROBLEM TO BE SOLVED: To suppress the deterioration of the frequency characteristic of an SAW element and to improve reliability. SOLUTION: An area 14 formed as a rough surface is provided on the inner side than the margin frame 10a of an outer periphery of an SAW substrate 10 where an SAW filter is formed. Consequently, it is possible to suppress reaching of a bulk wave to the sides of output-side electrodes 22a and 22b by irregularly reflecting the bulk wave in an area 14 on the rear surface. As a result, the deterioration of the frequency characteristic can be suppressed. Since a rough surface is not formed on the outer side than the frame 10a, the occurrence of crack in dicing can be suppressed. As a result, the reliability of the SAW filter is improved.
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