Patent ID: 7448119
Filing Date: 2008-11-11
Classification: H01L,H03H,Y10T

Abstract:
1. A method of producing a surface acoustic wave device comprising a piezoelectric substrate, a comb electrode, and a reflector, the comb electrode converting a surface acoustic wave, which is generated at the piezoelectric substrate, and an electrical signal into each other, the reflector being disposed adjacent to the comb electrode as viewed in a direction of propagation of the surface acoustic wave and reflecting the surface acoustic wave propagating along the piezoelectric substrate towards the comb electrode, at least a surface of the piezoelectric substrate being sealed by a sealing resin while a space is formed that covers an area, where the comb electrode and the reflector are formed, on the surface of the piezoelectric substrate, the method comprising: an etching step of etching a metallic film formed on the surface of the piezoelectric substrate to form the comb electrode and the reflector at the surface of the piezoelectric substrate so as to be arranged in a predetermined direction of propagation of the surface acoustic wave when the etching step is completed; a sacrificial-layer forming step of forming a sacrificial layer, having an external shape corresponding to a shape of the space, at a location on the surface of the piezoelectric surface so as to cover the comb electrode and the reflector and so as to extend along the predetermined direction; a space-forming-member forming step of forming a space-forming member by adhering a material along an outer surface of the sacrificial layer extending along the predetermined direction, the space-forming member that is formed being disposed on the surface of the piezoelectric substrate while surrounding the outer surface of the sacrificial layer, extending along the predetermined direction, and having an opening, the opening being disposed at an end of the space-forming member as viewed in the predetermined direction and exposing the sacrificial layer; a sacrificial-layer removing step of removing the sacrificial layer from the surface of the piezoelectric substrate through the opening of the space-forming member; and after the sacrificial-layer removing step, performing a resin sealing step of sealing the surface of the piezoelectric substrate with the sealing resin while the space is formed between the comb electrode and the reflector by the space-forming member.