Elastic wave device and method for manufacturing the same

Abstract

An elastic wave device includes a substrate, a vibrating portion located on a first main surface of the substrate, pads located on the first main surface of the substrate and electrically connected to electrodes of the vibrating portion, a supporting layer arranged on the first main surface of the substrate so as to enclose the vibrating portion, a sheet-shaped cover layer composed of resin including synthetic rubber and disposed on the supporting layer so as to form a hollow space around the periphery of the vibrating portion, a protective layer composed of resin having resistance to flux and disposed on a side of the cover layer remote from the supporting layer, via conductors extending through the protective layer, the cover layer, and the supporting layer and connected to the pads, and external electrodes including solder bumps, disposed at ends of the via conductors adjacent to the protective layer.

What is claimed is: 
     
         1 . A method for manufacturing an elastic wave device comprising:
 a first step of forming a vibrating portion and a pad electrically connected to an electrode of the vibrating portion on a first main surface of a substrate;   a second step of forming a supporting layer having a thickness larger than a thickness of the vibrating portion on the first main surface of the substrate so as to enclose the vibrating portion;   a third step of forming a sheet-shaped cover layer composed of resin including synthetic rubber on the supporting layer so as to cover the vibrating portion and so as to form a hollow space around a periphery of the vibrating portion;   a fourth step of forming a protective layer composed of resin having resistance to flux on a side of the cover layer remote from the supporting layer;   a fifth step of forming a via conductor extending through the protective layer, the cover layer, and the supporting layer and connected to the pad; and   a sixth step of forming an external electrode including a solder bump at an end of the via conductor adjacent to the protective layer.   
     
     
         2 . A method for manufacturing an elastic wave device comprising:
 a first step of forming a vibrating portion and a pad electrically connected to an electrode of the vibrating portion on a first main surface of a substrate;   a second step of forming a supporting layer having a thickness larger than a thickness of the vibrating portion on the first main surface of the substrate so as to enclose the vibrating portion;   a third step of forming a sheet-shaped multiple layer formed of a sheet-shaped cover layer composed of resin including synthetic rubber and a protective layer composed of resin having resistance to flux stacked in advance on the supporting layer such that the protective layer is located on a surface of the cover layer remote from the supporting layer so as to cover the vibrating portion and to form a hollow space around a periphery of the vibrating portion;   a fourth step of forming a via conductor extending through the protective layer and the cover layer of the multiple layer and the supporting layer and connected to the pad; and   a fifth step of forming an external electrode including a solder bump at an end of the via conductor adjacent to the protective layer.   
     
     
         3 . The method for manufacturing the elastic wave device according to  claim 1 , further comprising:
 a seventh step of forming a groove in the substrate from the first main surface of the substrate to a predetermined depth; and   an eighth step of grinding a second main surface of the substrate opposite to the first main surface so as to reduce the thickness of the substrate and to divide the substrate into chips.   
     
     
         4 . The method for manufacturing the elastic wave device according to  claim 2 , further comprising:
 a sixth step of forming a groove in the substrate from the first main surface of the substrate to a predetermined depth; and   a seventh step of grinding a second main surface of the substrate opposite to the first main surface so as to reduce the thickness of the substrate and to divide the substrate into chips.