Surface acoustic wave devices having a guard layer

A surface acoustic wave device comprising:

• a dielectric substrate comprising an input electrode and an output electrode and a grounding electrode on a first surface of said dielectric substrate, and an outer electrode on a second surface of said dielectric substrate;
• a surface acoustic wave element comprising an electrode pad and a comb-shaped electrode disposed on a first surface of said surface acoustic wave element, said surface acoustic wave element bonded to said dielectric substrate by face-down method via a metal bump and a conductive resin formed on said electrode pad;
• an insulating resin deposited on the periphery of said metal bump;
• and
• a guard layer shorter in height than the surface acoustic wave element, said guard layer being formed adjacent the surface acoustic wave element on said first surface of said dielectric substrate,
• wherein the guard layer comprises the same dielectric material as the dielectric substrate.

A surface acoustic wave device comprising:

• a dielectric substrate comprising an input electrode and an output electrode and a grounding electrode on a first surface os said dielectric substrate, and an outer electrode on a second surface of said dielectric substrate,
• a surface acoustic wave element comprising an electrode pad and a comb-shaped electrode disposed on a first surface of said surface acoustic wave element, said surface acoustic wave element bonded to said dielectric substrate by face-down method via a metal bump and a conductive resin formed on said electrode pad,
• an insulating resin deposited on the periphery of said metal bump, and
• a guard layer shorter in height than the surface acoustic wave element, said guard layer being formed adjacent the surface acoustic wave element on said first surface of said dielectric substrate,
• wherein a second guard layer is formed on the first surface of the surface acoustic wave element so as to be positioned between the metal bump and comb-shaped electrode.