Elastic surface wave apparatus and mfg. method thereof

一种弹性表面波装置，由以下部分构成：在钽酸锂压电衬底的一主面上形成了IDT电极、连接电极和外周密封电极的弹性表面波元件；形成了通过焊锡凸台构件与所述连接电极连接的元件连接用电极、通过焊锡密封构件与所述外周密封电极接合的外周密封导体膜的基衬底。而且，焊锡凸台构件和焊锡密封构件使用包含90％以上Sn的Sn-Sb类或Sn-Ag类的无铅焊锡，所述基衬底的热膨胀系数设定为9～20ppm/℃。可以提供一种对于热膨胀系数差引起的热应力能非常稳定地接合，并且能够维持长期稳定连接的弹性表面波装置。 A surface acoustic wave device is disclosed, which comprises a surface acoustic wave element including a lithium tantalate piezoelectric substrate 10 with one principal surface thereof formed with an IDT electrode 11, a connector electrode 12 and a periphery sealing electrode 13, and a base substrate 2 formed with an electrode 21 for connection to the element connected to the connector electrode 12 through a solder bump component 3 and a periphery sealing conductor film 22 joined to the periphery sealing electrode 13 thorough a solder sealing component 4. For the solder bump component 3 and the solder sealing component 4, a Sn-Sb based or Sn-Ag based lead-free solder containing 90% or more Sn is used, and the thermal expansion coefficient of the base substrate 2 is set in the range of 9-20 pm/° C. The joining is accomplished with high stability resisting thermal stress due to a difference in thermal expansion coefficient, so that a surface acoustic wave device that can maintain stable connection for a long duration of time can be provided.