JP2014171116A - Piezoelectric device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device in which splash caused by seam-welding does not influence the inside of a cavity, and the method of manufacturing the same.SOLUTION: The piezoelectric device (100) includes: a package (120) which has a cavity (121) surrounded by a bottom surface (121a) and a lateral wall (121b) and has a long side and a short side; a piezoelectric vibration piece (110) carried by the cavity; a metallization film (150) which is disposed on a top face of the lateral wall and extends up to an outside lateral face (128b) of the lateral wall on the whole outer periphery of the top face; and a metal lid (130) which seals the cavity with its whole circumference welded to the metallization film.

Description

  The present invention relates to a piezoelectric device in which a metal lid is seam welded to a metallized film formed on a package, and a method for manufacturing the piezoelectric device.

  A piezoelectric device is known in which a piezoelectric vibrating piece is placed on a package in which a cavity surrounded by a bottom surface and a side wall is formed, and the cavity is sealed by seam welding a metal lid to a metallized film formed on the top surface of the side wall. ing. Patent Document 1 describes that a direct seam method in which a metal lid is seam welded directly to a metallized film is used for welding the metallized film and the metal lid. In the direct seam method, the entire package can be reduced in height by not using a seal ring, and the cost of the package can be reduced.

JP 2006-114710 A

  However, the size of the package has been reduced due to the miniaturization of the piezoelectric device, and the width of the upper surface of the side wall of the cavity in which the metallized film is formed has also been reduced. Therefore, in the direct seam method as shown in Patent Document 1, splash (metal melted) jumps into the cavity during seam welding of the metallized film and the metal lid, and problems such as adhesion of foreign matter occur. This could cause a failure of the piezoelectric device.

  Therefore, the present invention provides a piezoelectric device in which the influence of splash by seam welding does not reach the inside of the cavity and a method for manufacturing the piezoelectric device.

  A piezoelectric device according to a first aspect includes a cavity surrounded by a bottom surface and a side wall, a package having a long side and a short side, a piezoelectric vibrating piece placed in the cavity, and an upper surface of the side wall. A metallized film that extends to the outer side surface of the side wall at the outer periphery, and a metal lid that is welded to the metallized film to seal the cavity.

  In the piezoelectric device according to the second aspect, in the first aspect, the metallized film includes a tungsten film, a nickel film formed on the surface of the tungsten film, and a gold film formed on the surface of the nickel film.

  A piezoelectric device according to a third aspect includes an integrated circuit that oscillates a piezoelectric vibrating piece in the first aspect and the second aspect.

  According to a fourth aspect of the present invention, there is provided a method of manufacturing a piezoelectric device, comprising: preparing a package having a long side and a short side, and forming a cavity surrounded by a bottom surface and a side wall; A metallized film forming process for forming a metallized film extending to the outer side surface, a piezoelectric vibrating piece mounting process for mounting a piezoelectric vibrating piece in the cavity, and a metal lid are welded to the metallized film to seal the cavity. And a step of performing.

  In the fourth aspect of the method for manufacturing a piezoelectric device according to the fifth aspect, the metallized film is also formed on the outer side surface of the side wall in the metallized film forming step.

  According to a sixth aspect of the piezoelectric device manufacturing method, in the fourth and fifth aspects, the metallized film forming step includes a step of forming a tungsten film on the upper surface of the sidewall by screen printing, and a nickel plating is applied to the surface of the tungsten film. And a step of forming gold on the surface of the nickel plating film by gold plating.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a piezoelectric device and a piezoelectric device which the influence of the splash by seam welding does not reach in a cavity can be provided.

1 is an exploded perspective view of a piezoelectric device 100. FIG. It is AA sectional drawing of FIG. 3 is a flowchart showing a method for manufacturing the piezoelectric device 100. It is a flowchart of a metallized film formation process. 2 is a top view of a package 120 in which a tungsten film 151 is formed on a bonding surface 122. FIG. 1 is a schematic perspective view of a piezoelectric device 100 that is seam welded. FIG. (A) is CC sectional drawing of FIG. FIG. 7B is an enlarged view of a dotted line 162 in FIG. 2 is an exploded perspective view of a piezoelectric device 200. FIG. It is DD sectional drawing of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

(First embodiment)
<Configuration of Piezoelectric Device 100>
FIG. 1 is an exploded perspective view of the piezoelectric device 100. The piezoelectric device 100 is mainly formed by a piezoelectric vibrating piece 110, a package 120, and a metal lid 130. As the piezoelectric vibrating piece 110, for example, an AT-cut crystal vibrating piece can be used. The AT-cut quartz crystal resonator element has a principal surface (YZ plane) inclined with respect to the Y axis of the crystal axis (XYZ) by 35 degrees 15 minutes from the Z axis in the Y axis direction around the X axis. In the following description, the new axes tilted with respect to the axial direction of the AT-cut quartz crystal vibrating piece are used as the Y ′ axis and the Z ′ axis. That is, the piezoelectric device is described with the direction in which the long side extends as the X-axis direction, the direction in which the short side extends as the Z′-axis direction, and the height direction as the Y′-axis direction. At this time, the X-axis direction, the Y′-axis direction, and the Z′-axis direction are perpendicular to each other.

  The piezoelectric vibrating piece 110 is formed in a rectangular shape. Excitation electrodes 111 are respectively formed on the surface on the + Y′-axis side and the surface on the −Y′-axis side of the piezoelectric vibrating piece 110. From each excitation electrode 111, the + Z′-axis side and the −Z′-side of the −X-axis side are formed. An extraction electrode 112 is extracted at each corner on the shaft side.

  The package 120 has a long side extending in the X-axis direction and a short side extending in the Z′-axis direction. Further, external electrodes 125 are formed on the + X axis side and the −X axis side of the surface on the −Y ′ axis side, respectively. On the surface at the + Y′-axis side, a cavity 121 is formed that is surrounded by the bottom surface 121a and the side wall 121b and in which the piezoelectric vibrating piece 110 is disposed. In addition, a placement portion 123 is formed on each of the + Z′-axis side and the −Z′-axis side of the cavity 121 on the −X-axis side. An electrode 124 is formed. The piezoelectric vibrating piece 110 is placed on the placement portion 123.

  The package 120 is a ceramic package based on, for example, a ceramic, and is formed by superimposing three layers, a first layer 120a, a second layer 120b, and a third layer 120c. The first layer 120 a forms a surface at the −Y′-axis side of the package 120 and a bottom surface 121 a of the cavity 121. The second layer 120 b is disposed on the surface at the + Y′-axis side of the first layer 120 a, and forms the mounting portion 123 in the cavity 121 and forms part of the side wall 121 b of the cavity 121. The third layer 120 c is disposed on the surface at the + Y′-axis side of the second layer 120 b, forms the bonding surface 122 on the surface at the + Y′-axis side, and forms part of the side wall 121 b of the cavity 121. A metallized film 150 is formed on the bonding surface 122.

  The metal lid 130 is formed in a planar shape, and is seam welded to the metallized film 150 formed on the bonding surface 122 of the package 120. As a result, the metal lid 130 seals the cavity 121. The metal lid 130 is made of a metal such as Kovar, for example, and the surface thereof is plated with nickel to form a nickel film (not shown).

  FIG. 2 is a cross-sectional view taken along the line AA of FIG. In the package 120, the bottom surface 121a of the cavity 121 is formed by the first layer 120a, and the side wall 121b of the cavity 121 is formed by the second layer 120b and the third layer 120c. The side wall 121 b has an inner side surface 128 a facing the cavity 121 and an outer side surface 128 b opposite to the cavity 121. Further, the upper surface of the side wall 121 b on the + Y′-axis side is a bonding surface 122, and a metallized film 150 is formed on the bonding surface 122. The metallized film 150 has an extended portion 150a extending to the outer side surface 128b of the side wall 121b, and a metal lid 130 is welded to the metallized film 150. The piezoelectric vibrating piece 110 is placed on the placement portion 123 in the cavity 121 of the piezoelectric device 100 by joining the extraction electrode 112 to the connection electrode 124 via the conductive adhesive 140. The connection electrode 124 is electrically connected to the external electrode 125 via a through electrode 127 that penetrates the package 120. Thereby, the excitation electrode 111 of the piezoelectric vibrating piece 110 is electrically connected to the external electrode 125.

<Method for Manufacturing Piezoelectric Device 100>
FIG. 3 is a flowchart showing a method for manufacturing the piezoelectric device 100. Hereinafter, the manufacturing method of the piezoelectric device 100 will be described using this flowchart.

  In step S101 of FIG. 3, a package 120 is prepared. Step S101 is a process of preparing a package. In the package 120 prepared in step S101, the first layer 120a, the second layer 120b, and the third layer 120c are overlapped to form the connection electrode 124, the through electrode 127, the external electrode 125, and the like. In step S101, the metallized film 150 has not yet been formed.

  In step S <b> 102, the metallized film 150 is formed on the bonding surface 122. Step S102 is a metallized film forming step. The metallized film 150 is composed of, for example, a tungsten film 151, a nickel film 152, and a gold film 153. Hereinafter, a method for forming the metallized film 150 will be described with reference to FIGS.

  FIG. 4 is a flowchart of the metallized film forming process. In FIG. 4, a partial cross-sectional view including a joint surface 122 for explaining each step of the flowchart is shown on the right side of the flowchart. This partial cross-sectional view includes a BB cross section of FIG. 5 described later.

  In step S201 in FIG. 4, a tungsten film 151 is formed on the bonding surface 122 by screen printing. Step S201 is a step of forming a tungsten film by screen printing. FIG. 4A is a partial cross-sectional view including the bonding surface 122 in a state where the tungsten film 151 is formed on the bonding surface 122. FIG. 4A shows a part of the side wall 121b on the + Y′-axis side, and a cavity 121 is formed on the side of the side wall 121b on the + X-axis side. Therefore, in FIG. 4A, the + X-axis side surface of the side wall 121b is the inner side surface 128a, and the −X-axis side surface of the side wall 121b is the outer side surface 128b. A tungsten film 151 is formed on the bonding surface 122 which is the surface on the + Y′-axis side of the side wall 121b by screen printing. Further, the tungsten film 151 is printed by protruding from the bonding surface 122 to the outer side surface 128b side. Therefore, immediately after the tungsten film 151 is screen-printed, the tungsten film 151 is formed with a protruding portion 151 a that protrudes from the bonding surface 122 to the outer side surface 128 b side. Thereafter, the protruding portion 151a hangs down in the −Y′-axis direction due to its own weight, and sticks to the outer side surface 128b to become the extended portion 151b of the tungsten film 151.

  FIG. 5 is a top view of the package 120 in which the tungsten film 151 is formed on the bonding surface 122. The connection electrode 124 on the + Z′-axis side of the package 120 is electrically connected to the external electrode 125 formed on the + X-axis side through the bottom surface 121 a and the through electrode 127. In FIG. 5, the tungsten film 151 formed on the bonding surface 122 of the package 120 by screen printing is indicated by a dotted line. The tungsten film 151 is formed over the entire circumference of the bonding surface 122. Further, the tungsten film 151 is formed so as to extend toward the outer side surface 128b on the entire outer periphery of the bonding surface 122 on the outer side surface 128b side. Therefore, the extending portion 151 b of the tungsten film 151 is formed so as to surround the bonding surface 122. As shown in FIG. 5, the end 151c on the inner peripheral side of the tungsten film 151 is formed so as to be slightly closer to the outer side surface 128b side from the inner side surface 128a on the bonding surface 122. An end 151c on the inner peripheral side of the tungsten film 151 may be formed so as to overlap the inner side surface 128a in FIG.

  The length of the cavity 121 of the package 120 in the X-axis direction is the length L1, the length in the Z′-axis direction is the length S1, the entire length of the package 120 in the X-axis direction is the length L2, and the length in the Z′-axis direction. The length is defined as length S2. At this time, if the length of the outer periphery of the tungsten film 151 in the X-axis direction is the length L4 and the length in the Z′-axis direction is the length S4, the tungsten film 151 is formed on the entire outer periphery of the bonding surface 122 on the outer side surface 128b side. Since the outer side surface 128b is extended and formed, the length L4 is longer than the length L2, and the length S4 is longer than the length S2. When the length of the inner circumference of the tungsten film 151 in the X-axis direction is a length L3 and the length of the inner circumference in the Z′-axis direction is a length S3, the tungsten film 151 is formed on the bonding surface 122. Therefore, the length L3 is longer than the length L1 and shorter than the length L2, and the length S4 is longer than the length S1 and shorter than the length S2.

  Returning to the flowchart of FIG. 4, in step S202, a nickel film 152 is formed on the surface of the tungsten film 151 by nickel plating. Step S202 is a process of applying nickel plating. FIG. 4B is a partial cross-sectional view including the bonding surface 122 in which the nickel film 152 is formed on the surface of the tungsten film 151. The nickel film 152 is formed by performing nickel plating on the surface of the tungsten film 151. Therefore, the nickel film 152 is formed so as to cover the surface of the tungsten film 151.

  In step S <b> 203, a gold film 153 is formed on the surface of the nickel film 152. Step S203 is a step of forming gold by gold plating. FIG. 5C is a partial cross-sectional view including the bonding surface 122 in which the gold film 153 is formed on the surface of the nickel film 152. By forming the gold film 153 on the surface of the nickel film 152 by gold plating, the gold film 153 is formed so as to cover the surface of the nickel film 152. Thereby, the metallized film 150 is formed on the bonding surface 122.

  Returning to FIG. 3, in step S <b> 103, the piezoelectric vibrating piece 110 is placed on the package 120. Step S103 is a piezoelectric vibrating piece placing step. As shown in FIG. 2, the piezoelectric vibrating piece 110 is placed in the package 121 by bonding the extraction electrode 112 to the connection electrode 124 via the conductive adhesive 140, and at the same time, the extraction electrode 112 and the connection electrode 124 is electrically connected.

  In step S <b> 104, the cavity 121 is sealed with the metal lid 130. Step S104 is a process of sealing the cavity. The cavity 121 is sealed by placing the metal lid 130 on the upper surface of the metallized film 150 formed on the bonding surface 122 and welding the metal lid 130 and the metallized film 150. The length of the metal lid 130 in the X-axis direction may be a length L2, and the length in the Z′-axis direction may be a length S2. The metal lid 130 is placed such that the outer periphery of the metal lid 130 and the outer periphery of the bonding surface 122 overlap in the Y′-axis direction. The metal lid 130 and the metallized film 150 are welded by a direct seam method in which the metal lid 130 and the metallized film 150 are directly seam welded.

  FIG. 6 is a schematic perspective view of the piezoelectric device 100 being seam welded. Seam welding is welding in which resistance welding is continuously performed by pressing the metal lid 130 with a pair of electrode rollers 160 and moving the electrode roller 160 on the sides of the metal lid 130 while rotating. While the electrode roller 160 is moving on the side of the metal lid 130, current is passed between the pair of electrode rollers 160 to generate Joule heat. The metal lid 130 and the metallized film 150 are welded by the Joule heat. Further, while the electrode roller 160 is moving on the metal lid 130, the pressure is always applied to the metal lid 130 by the electrode roller 160. For example, the electrode roller 160 moves the ± X-axis side of the metal lid 130 to perform welding on the ± X-axis side, and then moves the ± Z′-axis side to perform welding on the ± Z′-axis side. As a result, all the sides of the metal lid 130 are welded.

  Fig.7 (a) is CC sectional drawing of FIG. FIG. 7A shows a pair of electrode rollers 160 with dotted lines. FIG. 7A shows a state in which the pair of electrode rollers 160 are disposed to face the + Z′-axis side and the −Z′-axis side of the metal lid 130. Each electrode roller 160 is welded to the metal lid 130 and the metallized film 150 by moving while contacting the corner 131 of the metal lid 130.

  FIG. 7B is an enlarged view of a dotted line 162 in FIG. In the seam welding of the piezoelectric device 100, not all the region of the metal lid 130 in contact with the metallized film 150 is welded, and the metallized film 150 in the region 163 where the electrode roller 160 and the metallized film 150 are close to each other mainly. The metal lid 130 is welded. In the seam welding, the nickel film 152 of the metallized film 150 melts to form a raised portion 154 that rises on the side surface of the metal lid 130. When the length between the region 163 where the metallized film 150 and the metal lid 130 are welded to each other and the end 150c on the cavity 121 side of the metallized film 150 is a length LS, in the piezoelectric device 100, the metallized film 150 is outside. By extending to the side surface 128b, the length LS can be increased. In seam welding, splash (melted metal) may occur during welding. However, since the piezoelectric device 100 can take a large length LS, the splash may reach the cavity 121. As a result, the occurrence of defects such as a short circuit in the piezoelectric device 100 is prevented.

  Conventionally, it has been necessary to design a metal lid small in consideration of printing misalignment of the metallized film. However, in the piezoelectric device 100, the metallized film 150 is formed to extend to the outer side surface 128 b of the bonding surface 122. The metal lid 130 can be designed with the maximum dimensions without considering the printing misalignment of 150, and the sealing position, which is an area to be seam welded, can be maximized outside. Further, as described above, in the piezoelectric device 100, the metallized film 150 is formed to extend to the outer side surface 128b of the bonding surface 122, thereby forming a region to be seam welded at a location away from the cavity 121. Can do. Since seam welding is performed at a location away from the cavity 121, sparks such as splash generated during seam welding are prevented from scattering into the cavity 121.

  In the above embodiment, the side of the metal lid 130 and the outer side surface 128b do not necessarily coincide with the Y′-axis direction, and the side of the metal lid 130 may be formed closer to the cavity 121 than the outer side surface 128b. Further, the end 150c on the cavity 121 side of the metallized film 150 and the inner side surface 128a do not necessarily coincide with the Y′-axis direction, and the end 150c on the cavity 121 side of the metallized film 150 is on the outer side surface than the inner side surface 128a. It may be formed at a position close to the 128b side. However, it is desirable that a sufficient distance is provided between the region 163 to be welded and the cavity 121.

(Second Embodiment)
The piezoelectric device may be formed as a piezoelectric oscillator including an integrated circuit that oscillates a piezoelectric vibrating piece. Hereinafter, the piezoelectric device 200 having an integrated circuit will be described. Moreover, in the following description, the same part as 1st Embodiment is attached | subjected with the same number as 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 8 is an exploded perspective view of the piezoelectric device 200. The piezoelectric device 200 is a surface-mount type piezoelectric device, and is used by being mounted on a printed circuit board or the like. The piezoelectric device 200 shown in FIG. 8 is mainly formed by a piezoelectric vibrating piece 110, an integrated circuit 270, a package 220, and a metal lid 130.

  The package 220 has a long side extending in the X-axis direction and a short side extending in the Z′-axis direction. The package 220 is disposed on the −Y ′ axis side of the first layer 220a, the second layer 220b disposed on the + Y ′ axis side of the first layer 220a, and the + Y ′ axis side of the second layer 220b. The third layer 220c is formed. External electrodes 225 are respectively formed at the four corners of the surface on the −Y′-axis side of the package 220, and the piezoelectric vibrating piece 110 and the integrated circuit 270 are disposed on the surface on the + Y′-axis side surrounded by the bottom surface 221 a and the side wall 221 b. A cavity 221 to be formed is formed. Placed portions 223 are formed on the + Z′-axis side and the −Z′-axis side of the cavity 221 on the −X-axis side, respectively. A connection electrode 224 is formed on the upper surface of the mounting portion 223, and the extraction electrode 112 of the piezoelectric vibrating piece 110 is bonded to the upper surface via a conductive adhesive 140. The integrated circuit 270 is placed on the bottom surface 221a. On the + X-axis side of the cavity 221, a pillow portion 229 is formed that suppresses the tilt of the piezoelectric vibrating piece 110 and reduces the impact caused by the deflection. A bonding surface 222 is formed around the cavity 221 on the surface on the + Y′-axis side of the package 220, and a metallized film 250 is formed on the bonding surface 222.

  The integrated circuit 270 is electrically connected to the piezoelectric vibrating piece 110 to form an oscillation circuit. The integrated circuit 270 has a plurality of terminals formed on the surface at the −Y ′ axis side, and these terminals are electrically connected to the extraction electrode 112 of the piezoelectric vibrating piece 110 or the external electrode 225 formed on the package 220. .

  9 is a cross-sectional view taken along the line DD of FIG. In the piezoelectric device 200, the cavity 221 is sealed by performing seam welding similar to that of the first embodiment on the metallized film 250 on which the metal lid 130 is formed on the bonding surface 222. A piezoelectric electrode 242 electrically connected to the connection electrode 224 and a circuit electrode 243 electrically connected to the external electrode 225 are formed on the bottom surface 221 a of the package 220. The piezoelectric electrode 242 and the circuit electrode 243 are joined to the piezoelectric terminal 271 and the circuit terminal 272 formed in the integrated circuit 270 through the metal bump 141. Further, the side wall 221b of the package 220 has an inner side surface 228a formed on the cavity 221 side and an outer side surface 228b formed on the opposite side of the cavity 221, and the piezoelectric device 200 is the same as the piezoelectric device 100. In addition, the metallized film 250 is extended to the outer side surface 228b on the entire outer periphery of the bonding surface 222 to form an extended portion 250a. Further, the metallized film 250 is formed of a tungsten film, a nickel film, and a gold film, similarly to the metallized film 150 shown in FIG.

  As shown in the piezoelectric device 200 described above, even in the piezoelectric device having the integrated circuit 270, the metallized film is formed so as to extend to the outer side surface of the side wall on the entire outer periphery of the bonding surface. Can be formed away from Thereby, sparks such as splash generated during seam welding are prevented from scattering into the cavity 221, and defects such as a short circuit are prevented from occurring in the piezoelectric device 200.

  As described above, the optimal embodiment of the present invention has been described in detail. However, as will be apparent to those skilled in the art, the present invention can be implemented with various modifications and variations within the technical scope thereof.

  For example, in the above-described embodiment, the case where the piezoelectric vibrating piece is an AT-cut crystal vibrating piece has been described. However, the present invention can be similarly applied to a BT-cut quartz vibrating piece that vibrates in the thickness-slip mode. Furthermore, the piezoelectric vibrating piece can be basically applied not only to a quartz material but also to a bonding material including lithium tantalate, lithium niobate, or piezoelectric ceramic.

DESCRIPTION OF SYMBOLS 100, 200 ... Piezoelectric device 110 ... Piezoelectric vibrating piece 111 ... Excitation electrode 112 ... Extraction electrode 120, 220 ... Package 120a ... First layer 120b ... Second layer 120c ... Third layer 121, 221 ... Cavity 121a, 221a ... Bottom 121b 221b ... side wall 122 ... bonding surface 123, 223 ... mounting part 124, 224 ... connection electrode 125, 225 ... external electrode 127 ... through electrode 128a, 228a ... inner side surface 128b, 228b ... outer side surface 130 ... metal lid 131 ... corner Part 140 ... Conductive adhesive 141 ... Metal bump 150, 250 ... Metallized film 150a, 250a ... Extension part 150c ... End on the inner peripheral side of the metallized film 151 ... Tungsten film 151a ... Protruding part 151b ... Extension of the tungsten film 151c ... End of inner side of tungsten film 152 ... Nickel film 153 ... Gold film 154 ... Swelling part 160 ... Electrode roller 163 ... Area to be welded 229 ... Pillow part 242 ... Piezoelectric electrode 243 ... Circuit electrode 270 ... Integrated circuit 271 ... Piezoelectric terminal 272 ... Circuit terminal

Claims (6)

A package having a cavity surrounded by a bottom surface and side walls, having a long side and a short side;
A piezoelectric vibrating piece placed in the cavity;
A metallized film disposed on the upper surface of the side wall and extending to the outer side surface of the side wall on the entire outer periphery of the upper surface;
A metal lid that is welded around the metallized film to seal the cavity;
Piezoelectric device including:   The piezoelectric device according to claim 1, wherein the metallized film includes a tungsten film, a nickel film formed on a surface of the tungsten film, and a gold film formed on the surface of the nickel film.   The piezoelectric device according to claim 1, further comprising an integrated circuit that oscillates the piezoelectric vibrating piece. Preparing a package having a long side and a short side and forming a cavity surrounded by a bottom surface and a side wall;
Forming a metallized film on the upper surface of the side wall, extending to the outer side surface of the side wall on the entire outer periphery of the upper surface; and
A piezoelectric vibrating piece placing step of placing the piezoelectric vibrating piece in the cavity;
Sealing the cavity by welding the entire circumference of the metal lid to the metallized film;
A method of manufacturing a piezoelectric device having   The method for manufacturing a piezoelectric device according to claim 4, wherein in the metallized film forming step, the metallized film is also formed on an outer side surface of the side wall. The metallized film forming step includes
Forming a tungsten film on the upper surface of the sidewall by screen printing;
Applying nickel plating to the surface of the tungsten film;
Forming gold by gold plating on the surface of the nickel plating film;
The manufacturing method of the piezoelectric device of Claim 4 or Claim 5 containing these.

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