Piezoelectric resonator device, manufacturing method for piezoelectric...

Abstract

A piezoelectric vibration device includes a piezoelectric vibration plate where an excitation electrode is formed, and an upper lid member and a lower lid member that hermetically seal the excitation electrode, the piezoelectric vibration plate having a region where the upper lid member is joined and a region where the lower lid member is joined, on front and back main surfaces, the upper lid member having a region on one main surface where the piezoelectric vibration plate is joined, and the lower lid member having a region on one main surface where the piezoelectric vibration plate is joined. At least one of a substrate of the joining region of the piezoelectric vibration plate, a substrate of the joining region of the upper lid member, and a substrate of the joining region of the lower lid member has a roughened surface.

1 . A piezoelectric vibration device comprising:
 a piezoelectric vibration plate where an excitation electrode is formed; and   an upper lid member and a lower lid member that hermetically seal the excitation electrode,   the piezoelectric vibration plate having a region where the upper lid member is joined and a region where the lower lid member is joined, on front and back main surfaces,   the upper lid member having a region on one main surface where the piezoelectric vibration plate is joined,   the lower lid member having a region on one main surface where the piezoelectric vibration plate is joined and a region on the other main surface where an external member is joined,   wherein a joining layer constituting a joining material is formed in each of the joining region of the piezoelectric vibration plate, the joining region of the upper lid member, and the joining region of the lower lid member,   the joining region of the piezoelectric vibration plate and the joining region of the upper lid member are joined to each other via the joining materials,   the joining region of the piezoelectric vibration plate and the joining region of the lower lid member are joined to each other via the joining materials, and   at least one of a substrate of the joining region of the piezoelectric vibration plate, a substrate of the joining region of the upper lid member, and a substrate of the joining region of the lower lid member has a roughened surface.   
     
     
         2 . A piezoelectric vibration device comprising:
 a piezoelectric vibration plate where an excitation electrode is formed; and   an upper lid member and a lower lid member that hermetically seal the excitation electrode,   the upper lid member having a region on one main surface where the lower lid member is joined,   the lower lid member having a region on one main surface where the upper lid member is joined and a region on the other main surface where an external member is joined,   wherein a joining layer constituting a joining material is formed in each of the joining region of the upper lid member and the joining region of the lower lid member,   the joining region of the upper lid member and the joining region of the lower lid member are joined to each other via the joining materials, and   at least one of a substrate of the joining region of the upper lid member and a substrate of the joining region of the lower lid member has a roughened surface.   
     
     
         3 . The piezoelectric vibration device according to  claim 2 , wherein
 the lower lid member has a region on one main surface where the piezoelectric vibration plate is joined, and   a substrate of the joining region of the lower lid member where the piezoelectric vibration plate is joined has a roughened surface.   
     
     
         4 . The piezoelectric vibration device according to  claim 1 , wherein the joining layer formed on the roughened surface of the substrate of the joining region has a roughened surface. 
     
     
         5 . The piezoelectric vibration device according to  claim 1 , wherein
 the substrate of the joining region of the piezoelectric vibration plate has a roughened surface,   at least one of a substrate of the joining region of the upper lid member and a substrate of the joining region of the lower lid member has a roughened surface, and   the substrate of the joining region of at least one of the upper lid member and the lower lid member is formed to have a rougher surface than the substrate of the joining region of the piezoelectric vibration plate.   
     
     
         6 . The piezoelectric vibration device according to  claim 1 , wherein
 the joining region of at least one of the upper lid member and the lower lid member has a roughened surface, and   the joining region having a roughened surface is formed wider inwardly of the one main surface in plan view than the joining region of the piezoelectric vibration plate.   
     
     
         7 . The piezoelectric vibration device according to  claim 1 , wherein the entire main surface of at least one of the upper lid member and the lower lid member is roughened. 
     
     
         8 . The piezoelectric vibration device according to  claim 1 , wherein
 the joining region of the piezoelectric vibration plate has a roughened surface,   a multi-surface joining portion for joining the joining material to a plurality of surfaces having different planar directions is provided in the vicinity of the joining region of at least one of the upper lid member and the lower lid member, and   an enlargement preventing portion for preventing a region where the joining material is joined from being enlarged is provided outside the multi-surface joining portion.   
     
     
         9 . A manufacturing method for a piezoelectric vibration device comprising a piezoelectric vibration plate where an excitation electrode is formed, and an upper lid member and a lower lid member that hermetically seal the excitation electrode, the piezoelectric vibration plate having a region where the upper lid member is joined and a region where the lower lid member is joined on front and back main surfaces, the upper lid member having a region on one main surface where the piezoelectric vibration plate is joined, the lower lid member having a region on one main surface where the piezoelectric vibration plate is joined, wherein the joining region of the piezoelectric vibration plate and the joining region of the upper lid member are joined to each other via a joining material, and the joining region of the piezoelectric vibration plate and the joining region of the lower lid member are joined to each other via a joining material,
 the manufacturing method comprising:   a metal film formation step of laminating a metal film constituted by at least two types of metals on at least one of a substrate of the joining region of the piezoelectric vibration plate, a substrate of the joining region of the upper lid member, and a substrate of the joining region of the lower lid member;   a diffusion step of promoting metal diffusion inside the metal film by heat processing after the metal film formation step; and   an etching step of roughening a surface of the substrate by performing wet etching with an etchant caused to penetrate into the metal film obtained after the diffusion step and thereby forming a large number of micropores in the surface of the substrate.   
     
     
         10 . The manufacturing method for the piezoelectric vibration device according to  claim 9 , wherein
 the upper lid member and the lower lid member are made of crystal or glass,   the piezoelectric vibration plate is made of crystal,   the metal film formation step involves forming the metal film by forming a Cr layer on the substrate of at least one of the upper lid member, the lower lid member, and the piezoelectric vibration plate and laminating an Au layer on the Cr layer, so as to form a two-layer configuration of the Cr layer and the Au layer, and   the diffusion step involves roughening the surface of the substrate by diffusing Cr in the Cr layer into Au in the Au layer, performing wet etching using an etchant that is corrosive to the Cr and the crystal, and thereby forming a large number of micropores in the surface of the substrate.   
     
     
         11 . A method for etching a constituent member of a piezoelectric vibration device that has a region on at least one main surface where an external member is joined, the method comprising:
 a metal film formation step of laminating a metal film constituted by at least two types of metals on a substrate of the joining region of the constituent member;   a diffusion step of promoting metal diffusion inside the metal film by heat processing after the metal film formation step; and   an etching step of roughening a surface of the substrate by performing wet etching with an etchant caused to penetrate into the metal film obtained after the diffusion step and thereby forming a large number of micropores in the surface of the substrate.