JP2013021383A - Piezoelectric device - Google Patents

Abstract

The present invention provides a piezoelectric device having a base plate on which castellations are formed and being resistant to bending stress.
A piezoelectric device (100) includes a long base and a rectangular base plate (120a) formed by a short side shorter than the long side, and a piezoelectric vibrating piece (130) that vibrates at a predetermined frequency. In the device, a base plate is formed on a first surface (121) on which a pair of external electrodes are formed, a second surface (122) on which a piezoelectric vibrating piece is disposed, and a short side of the first surface. A pair of castellations (127) recessed inward from the side surface connecting the surface and the second surface, and the length of the pair of castellations in the long side direction is different.
[Selection] Figure 1

Description

  The present invention relates to a piezoelectric device having a base plate on which castellations are formed.

  There is known a piezoelectric device that is formed by a piezoelectric vibrating piece that vibrates at a predetermined frequency, a base plate, and a lid plate, and is used by being mounted on a printed circuit board or the like via solder. An excitation electrode is formed on the piezoelectric vibrating piece, and an external electrode to be mounted on a printed board or the like is formed on the base plate. A castellation is formed on the outer side surface of the base plate, and the excitation electrode and the external electrode are electrically connected via a side electrode formed on the castellation.

  The castellations formed in such a piezoelectric device are formed in various shapes. For example, Patent Document 1 discloses the shape and size of a castellation for suppressing cracks generated in solder when a piezoelectric device is mounted on a printed board.

JP 2006-196703 A

  However, on the other hand, due to the influence of such castellation, for example, when a bending test of a printed circuit board is performed, the base plate may be cracked starting from a part of the castellation. Therefore, it is desired that the base plate of the piezoelectric device is strong against such bending stress.

  Therefore, the present invention provides a piezoelectric device that has a base plate on which castellations are formed and is resistant to bending stress.

  A piezoelectric device according to a first aspect is a piezoelectric device having a rectangular base plate formed by a long side and a short side shorter than the long side, and a piezoelectric vibrating piece that vibrates at a predetermined frequency. A pair of first surfaces on which a pair of external electrodes are formed, a second surface on which the piezoelectric vibrating piece is disposed, and a pair of recesses recessed inward from a side surface formed on one short side and connecting the first surface and the second surface. And the length of the pair of castellations in the long side direction is different.

  A piezoelectric device according to a second aspect is a piezoelectric device having a rectangular base plate formed by a long side and a short side shorter than the long side, and a piezoelectric vibrating piece that vibrates at a predetermined frequency. A pair of first surfaces on which a pair of external electrodes are formed, a second surface on which the piezoelectric vibrating piece is disposed, and a long side of one side and recessed inward from a side surface connecting the first surface and the second surface. The length of the pair of castellations in the short side direction is different.

  A piezoelectric device according to a third aspect is a piezoelectric device having a rectangular base plate formed by a long side and a short side shorter than the long side, and a piezoelectric vibrating piece that vibrates at a predetermined frequency. A first surface on which a pair of external electrodes are formed, a second surface on which a piezoelectric vibrating piece is disposed, and a first side formed in a long side direction and a short side direction at a corner where a long side intersects a short side of one side. A pair of castellations recessed inward from the side surface connecting the surface and the second surface, and the length of the pair of castellations in the long side direction and the length in the short side direction are different.

  A piezoelectric device according to a fourth aspect is the piezoelectric device according to the first to third aspects, wherein the piezoelectric vibrating piece includes a pair of excitation electrodes and a pair of extraction electrodes extracted from the excitation electrodes, and the second surface of the base plate is a pair of extractions. A pair of connection electrodes electrically connected to the electrodes is included, and the castellation includes a pair of side electrodes electrically connecting the pair of external electrodes and the pair of connection electrodes.

  According to a fifth aspect of the piezoelectric device, in the fourth aspect, the castellation has a first curved surface formed from the first surface to the second surface, a second curved surface formed from the second surface to the first surface, and the second curved surface. The side surface electrode is formed on the first curved surface, the second curved surface, and the projecting surface, and includes a linear projecting surface formed between the first surface and the second surface.

  In the fourth aspect, the piezoelectric device of the fifth aspect has a larger area on the first curved surface than on the second curved surface.

  According to the present invention, it is possible to provide a piezoelectric device that has a base plate on which castellations are formed and is strong against bending stress.

1 is an exploded perspective view of a piezoelectric device 100. FIG. (A) is AA sectional drawing of FIG. FIG. 4B is a plan view of the surface on the + Y′-axis side of the piezoelectric vibrating piece 130. FIG. 6C is a plan view of a surface on the −Y′-axis side of the piezoelectric vibrating piece 130. FIG. 4A is a plan view showing an electrode on the + Y′-axis side of the base plate 120a. FIG. 5B is a plan view showing an electrode on the −Y′-axis side of the base plate 120a. 3 is a flowchart illustrating a method for manufacturing the piezoelectric device 100. (A) is a top view of base wafer W120A. FIG. 6B is a plan view showing the + Y′-axis side electrode of the base plate 120b. (C) is a plan view showing an electrode on the −Y′-axis side of the base plate 120 b. It is a top view of the lid wafer W110. (A) is a partial top view of base wafer W120B. (B) is a plan view of the base plate 120c. (C) is a plan view of the base plate 120d. (A) is a partial top view of base wafer W120C. (B) is a plan view of the base plate 120e. (C) is a plan view of the base plate 120f. (A) is a partial top view of base wafer W120D. (B) is a partial plan view of the base wafer W120E. (C) is a partial plan view of the base wafer W120F. 2 is an exploded perspective view of a piezoelectric device 200. FIG. (A) is BB sectional drawing of FIG. (B) is a plan view of the base plate 220a. FIG. 6C is a plan view of the base plate 220a on which electrodes on the surface at the −Y′-axis side are shown. 5 is a flowchart illustrating a method for manufacturing the piezoelectric device 200. It is a top view of the piezoelectric wafer W230. It is a top view of base wafer W220A. It is the flowchart which showed the preparation methods of base wafer W220A. It is the flowchart which showed the preparation methods of base wafer W220A. (A) is a top view of base wafer W220B. (B) is a plan view of the base plate 220c. (C) is a plan view of the base plate 220c showing the electrodes on the surface at the -Y'-axis side.

  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 a surface-mount type piezoelectric device, and is used by being mounted on a printed circuit board or the like. The piezoelectric device 100 mainly includes a lid plate 110, a base plate 120a, and a piezoelectric vibrating piece 130. The lid plate 110 is formed of, for example, ceramic, glass, or a piezoelectric material, and the base plate 120a is formed of glass, a piezoelectric material, or the like. The piezoelectric vibrating piece 130 is made of, for example, an AT-cut quartz material. In the AT-cut quartz crystal material, the main surface (YZ plane) is inclined 35 degrees 15 minutes from the Z axis in the Y axis direction with respect to the Y axis of the crystal axis (XYZ). In the following description, the new axes tilted with respect to the axial direction of the AT-cut quartz material are used as the Y ′ axis and the Z ′ axis. That is, in the piezoelectric device 100, the long side direction of the piezoelectric device 100 is described as the X-axis direction, the height direction of the piezoelectric device 100 is defined as the Y′-axis direction, and the direction perpendicular to the X and Y′-axis directions is described as the Z′-axis direction.

  The lid plate 110 is formed in a rectangular shape having long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. A recess 111 is formed on the surface at the −Y′-axis side of the lid plate 110, and a bonding surface 112 to be bonded to the base plate 120 a is formed around the recess 111.

  The base plate 120a is formed in a rectangular shape having long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. The first surface 121, which is the surface on the −Y′-axis side of the base plate 120a, is charged with the external electrode 125, which is an electrode to be electrically connected to a printed circuit board or the like via solder, and the piezoelectric device 100 A ground terminal 126 for removing static electricity or the like is formed. A bonding material 140 is formed on the second surface 122 which is the surface on the + Y′-axis side of the base plate 120 a and is bonded to the bonding surface 112 of the lid plate 110. The base plate 120a has a recess 123 that is recessed from the second surface 122 in the −Y′-axis direction. Further, a mounting portion 124 for mounting the piezoelectric vibrating piece 130 is formed on a part of the second surface 122, and a connection electrode 128 is formed on the surface of the mounting portion 124 on the + Y ′ axis side. ing. Further, castellations 127 are formed on the side surfaces of the four corners of the base plate 120a. A side electrode 129 is formed on the castellation 127, and the side electrode 129 electrically connects the external electrode 125 and the connection electrode 128 to each other or is electrically connected to the ground terminal 126.

  The piezoelectric vibrating piece 130 is formed in a rectangular shape having long sides extending in the X-axis direction and short sides extending in the Z′-axis direction. Excitation electrodes 131 are respectively formed in the central regions of the surfaces on the + Y′-axis side and the −Y′-axis side of the piezoelectric vibrating piece 130. In addition, an extraction electrode 132 is extracted from each excitation electrode 131. The extraction electrode 132 drawn from the excitation electrode 131 formed on the surface on the + Y′-axis side is formed along the side on the −X-axis side of the surface on the + Y′-axis side of the piezoelectric vibration piece 130, and further the piezoelectric vibration piece It is formed along the side on the −X axis side of the surface on the −Y ′ axis side via an extraction electrode 132 a formed on the side surface on the −X axis side of 130. Similarly, the extraction electrode 132 drawn from the excitation electrode 131 formed on the surface at the −Y′-axis side is formed along the side on the + X-axis side of the surface at the −Y′-axis side of the piezoelectric vibrating piece 130, Further, the piezoelectric vibrating piece 130 is formed along the + X-axis side side of the + Y′-axis side surface through an extraction electrode 132 a formed on the + X-axis side surface of the piezoelectric vibrating piece 130. In the piezoelectric vibrating piece 130, the excitation electrode 131 and the external electrode 125 are electrically connected by connecting the connection electrode 128 and the extraction electrode 132 of the base plate 120 a via the conductive adhesive 141 (see FIG. 2). Connected.

  FIG. 2A is a cross-sectional view taken along the line AA in FIG. In the piezoelectric device 100, the second surface 122 of the base plate 120a and the bonding surface 112 of the lid plate 110 are bonded to each other through the bonding material 140, whereby a sealed cavity 101 is formed in the piezoelectric device 100. . As the bonding material 140, for example, a low-melting glass which is a glass bonding material having a melting point of 500 degrees or less, or a resin-based bonding material such as polyimide resin is used. In addition, the piezoelectric vibrating piece 130 is placed on the placement portion 124 of the base plate 120 a of the cavity 101 by joining the extraction electrode 132 and the connection electrode 128 via the conductive adhesive 141. Since the piezoelectric vibrating piece 130 is placed on the placement portion 124, the excitation electrode 131 of the piezoelectric vibrating piece 130 is brought into contact with the base plate via the extraction electrode 132, the conductive adhesive 141, the connection electrode 128, and the side electrode 129. It is electrically connected to the external electrode 125 of 120a.

  FIG. 2B is a plan view of the surface on the + Y′-axis side of the piezoelectric vibrating piece 130. The piezoelectric vibrating piece 130 has a rectangular plane having a long side in the X-axis direction and a short side in the Z′-axis direction. An excitation electrode 131 is formed in the central region of the surface on the + Y′-axis side of the piezoelectric vibrating piece 130, and an extraction electrode 132 is drawn from the excitation electrode 131 on the −X-axis side. The extraction electrode 132 drawn to the −X-axis side side is formed along the −X-axis side side of the piezoelectric vibrating piece 130, and is further formed on the −X-axis side side surface of the piezoelectric vibrating piece 130. It is led out to the surface on the −Y′-axis side of the piezoelectric vibrating piece 130 via the lead electrode 132 a. In addition, an extraction electrode 132 extracted from the excitation electrode 131 on the −Y ′ axis side is formed along the + X axis side side on the + X axis side side of the surface on the + Y ′ axis side of the piezoelectric vibrating piece 130. Yes.

  FIG. 2C is a plan view of the surface at the −Y′-axis side of the piezoelectric vibrating piece 130. An excitation electrode 131 is formed in the central region of the surface on the −Y′-axis side of the piezoelectric vibrating piece 130, and an extraction electrode 132 is drawn from the excitation electrode 131 on the + X-axis side. The extraction electrode 132 drawn to the side on the + X axis side is formed along the side on the + X axis side of the piezoelectric vibrating piece 130, and further, the extraction electrode 132 a formed on the side surface on the + X axis side of the piezoelectric vibrating piece 130. Through the surface of the piezoelectric vibrating piece 130 on the + Y′-axis side. In addition, on the −X′-side side of the −Y′-axis side surface of the piezoelectric vibrating piece 130, an extraction electrode 132 drawn from the + Y′-axis side excitation electrode 131 is formed along the −X-axis side side. Has been.

  FIG. 3A is a plan view showing the + Y′-axis side electrode of the base plate 120a. A recess 123 is formed on the surface on the + Y′-axis side of the base plate 120 a, and a second surface 122 is formed so as to surround the recess 123. In addition, on the −Z′-axis side on the + X-axis side of the concave portion 123 and the + Z′-axis side on the −X-axis side, a mounting portion 124 for mounting the piezoelectric vibrating piece 130 is formed. A connection electrode 128 is formed on the surface of the 124 on the + Y ′ axis side. On the other hand, castellations 127 are formed on the side surfaces of the four corners of the base plate 120a. In the following description, the castellation 27a on the + Z-axis side on the + X-axis side, the castellation 27b on the + Z-axis side on the + X-axis side, and the -Z'-axis side on the -X-axis side in the description. The castellation will be described as castellation 27c, and the + Z′-axis side castellation on the −X-axis side will be described as castellation 27d. The castellations 27a and 27d are formed to have a length LX1 in the X-axis direction and a width LZ1 in the Z′-axis direction. On the other hand, the castellation 27b and the castellation 27c are formed to have a length LX2 in the X-axis direction and a length LZ2 in the Z′-axis direction. The length LX1 is longer than the length LX2, and the length LZ1 is shorter than the length LZ2. The side electrode 129 formed on the castellation 27a and the castellation 27d electrically connects the connection electrode 128 and the external electrode 125, and the side electrode 129 formed on the castellation 27b and the castellation 27c is grounded. It is electrically connected to the terminal 126 (see FIG. 3B).

  The base plate 120a is different from the castellations in which the castellations formed on the base plate 120a are adjacent in the X-axis direction and the Z′-axis direction in the Z′-axis direction and the X-axis direction, respectively. For example, the castellation 27a is formed to have a length LX1 in the X-axis direction, but the castellation 27b adjacent to the + Z'-axis direction of the castellation 27a has a length in the X-axis direction that is LX2. Different lengths are formed in the X-axis direction. Therefore, a straight line 171 that connects a corner 171a that is recessed toward the base plate 120a at the end on the −X-axis side of the castellation 27a and a corner 171b that is recessed toward the base plate 120a at the end on the −X-axis side of the castellation 27b. Is not parallel to the Z ′ axis. Further, the castellations 27a are formed in the length LZ1 in the Z′-axis direction, but the castellations 27c adjacent in the −X-axis direction are formed in the length LZ2 in the Z′-axis direction and are mutually Z ′. The length is different in the axial direction. Therefore, a straight line 172 that connects a corner 172a that is recessed toward the base plate 120 at the + Z′-axis end of the castellation 27a and a corner 172b that is recessed toward the base plate 120 at the + Z′-axis end of the castellation 27c. Are not parallel to the X axis.

  FIG. 3B is a plan view showing an electrode on the −Y′-axis side of the base plate 120a. In FIG. 3B, the electrode formed on the −Y′-axis side of the base plate 120a is shown as seen through the base plate 120a in the −Y′-axis direction from the + Y′-axis side. External electrodes 125 are formed on the −Z′-axis side on the + X-axis side and the + Z′-axis side on the −X-axis side of the surface on the −Y′-axis side of the base plate 120a. Each external electrode 125 is electrically connected to a connection electrode 128 formed on the surface on the + Y′-axis side via a side electrode 129. Further, the ground terminal 126 is formed on the + Z′-axis side on the + X-axis side and the −Z′-axis side on the −X-axis side of the surface on the −Y′-axis side.

  When a piezoelectric device is mounted on a printed board and subjected to a bending test of the printed board, a base plate may be cracked. This crack occurs starting from a corner (such as the corner 171a in FIG. 3A) recessed inside the castellation base plate and parallel to the X-axis direction or the Z′-axis direction. To do. In addition, such a crack is likely to occur near the center of the base plate, and the corners of castellations adjacent to each other in the X-axis direction or the Z′-axis direction are on a straight line parallel to the X-axis or the Z′-axis. It is easy to occur when there is. Because of this tendency, when a printed circuit board bending test is performed on the base plate, a straight line connecting the corners of the castellation passes near the center of the base plate, and the straight line is parallel to the X axis or the Z ′ axis. In this case, it is considered that a strong stress is applied to the base plate, or the base plate castellation is weak against bending stress when the base plate has corners that satisfy such conditions. The base plate 120a of the piezoelectric device 100 has, for example, straight lines 171 and 172 in FIG. 3A connecting the corners of the castellations and passing near the center of the base plate parallel to the X axis or the Z ′ axis. Therefore, the base plate 120a is not easily cracked. Further, in the piezoelectric device 100, the castellation is formed in an L shape extending in the X-axis direction and the Z′-axis direction, whereby the width of the side electrode 129 can be increased, and stable patterning and resistance value of the electrode can be achieved. Can be obtained.

  The base plate 120a is formed so that the corners of the castellation are connected to each other so that a straight line passing near the center of the base plate is not parallel to the X axis or the Z ′ axis. If the straight line passing near the center of the base plate is formed so as not to be parallel to either the X-axis or the Z′-axis, the base plate can be made difficult to crack.

<Method for Manufacturing Piezoelectric Device 100>
FIG. 4 is a flowchart showing a method for manufacturing the piezoelectric device 100. Hereinafter, a method for manufacturing the piezoelectric device 100 will be described with reference to FIG.

  In step S101, the piezoelectric vibrating piece 130 is prepared. The piezoelectric vibrating piece 130 is formed in a flat plate rectangular shape as shown in FIGS. 1, 2B, and 2C, and an excitation electrode 131 and an extraction electrode 132 are formed.

  In step S102, a base wafer is prepared. A plurality of base plates are formed on the base wafer. Hereinafter, the base wafer W120A will be described with reference to FIG.

  FIG. 5A is a plan view of the base wafer W120A. Two types of base plates, a base plate 120a and a base plate 120b, are formed on the base wafer W120A, and are alternately formed in the X-axis direction and the Z′-axis direction, respectively. In FIG. 5A, a scribe line 142, which is a line for cutting the wafer in step S106 described later, is indicated by a two-dot chain line. In FIG. 5A, the base plate 120a and the base plate 120b formed on the base wafer W120A are surrounded by a scribe line 142. A through hole 143a or a through hole 143b penetrating the base wafer W120A is formed at a position where the scribe line 142 extending in the X-axis direction and the scribe line 142 extending in the Z′-axis direction intersect. The planar shape of the through hole 143a is formed in a cross shape that extends long in the Z′-axis direction and short in the X-axis direction around the intersection of the scribe lines 142. The planar shape of the through hole 143b is formed in a cross shape that extends short in the Z′-axis direction and long in the X-axis direction around the intersection of the scribe lines 142. In the base plate 120a, a through hole 143a is disposed on the + Z ′ axis side on the + X axis side, and in the base plate 120b, the through hole 143b is disposed on the + Z ′ axis side on the + X axis side.

  FIG. 5B is a plan view showing the + Y′-axis side electrode of the base plate 120b. A recess 123 is formed on the surface on the + Y′-axis side of the base plate 120 b, and a second surface 122 is formed so as to surround the recess 123. Further, a mounting portion 124 is formed on the −Z′-axis side on the + X-axis side of the concave portion 123 and the + Z′-axis side on the −X-axis side, and the surface of the mounting portion 124 on the + Y′-axis side is formed. A connection electrode 128 is formed. On the other hand, castellations 27a to 27d are formed at the four corners of the base plate 120b, respectively. The shape of each castellation 27a to 27d formed on the base plate 120b in the XZ ′ plane is formed in an L shape extending in the X-axis direction and the Z′-axis direction in the same manner as the base plate 120a. Side electrodes 129 are formed on the castellations 27a to 27d. Each connection electrode 128 formed in the recess 123 is electrically connected to an external electrode 125 (see FIG. 5C) formed on the surface at the −Y′-axis side via the side electrode 129. .

  FIG. 5C is a plan view showing an electrode on the −Y′-axis side of the base plate 120b. In FIG. 5C, the electrode formed on the −Y′-axis side of the base plate 120b is shown as seen through the base plate 120b in the −Y′-axis direction from the + Y′-axis side. External electrodes 125 are formed on the −Z′-axis side on the + X-axis side and the + Z′-axis side on the −X-axis side of the surface on the −Y′-axis side of the base plate 120b. Each external electrode 125 is electrically connected to a connection electrode 128 formed on the surface on the + Y′-axis side via a side electrode 129. Further, a ground terminal 126 is formed on the + Z-axis side on the + X-axis side of the surface on the −Y′-axis side and the −Z′-axis side on the −X-axis side, and the ground terminal 126 is electrically connected to the side electrode 129. Connected.

  In the base wafer W120, the length of the through-hole 143a in the X-axis direction and the length of the through-hole 143b in the Z′-axis direction, and the length of the through-hole 143a in the Z′-axis direction and the length of the through-hole 143b in the X-axis direction. When equal, the lengths LX1 and LZ2 of the base plate 120a and the base plate 129b are equal, and the lengths LX2 and LZ1 are equal. At this time, the lengths of the cross sections of all the side electrodes 129 formed on the base plate 120a and the base plate 120b are equal. Therefore, when the piezoelectric device is formed, the electrical connection is equal regardless of whether the base plate 120a or the base plate 120b is used.

  Returning to FIG. 4, in step S103, a lid wafer is prepared. A plurality of lid plates are formed on the lid wafer. Hereinafter, the lid wafer W110 will be described with reference to FIG.

  FIG. 6 is a plan view of the lid wafer W110. A plurality of lid plates 110 are formed on the lid wafer W110. In FIG. 6, a scribe line 142 that is a line through which the wafer is cut in step S <b> 106 described later is indicated by a two-dot chain line, and each lid plate 110 formed on the lid wafer W <b> 110 is surrounded by the scribe line 142. Is shown. A recess 111 is formed on the surface of each lid plate 110 on the −Y′-axis side.

  In step S104, the piezoelectric vibrating piece 130 is placed on the base wafer W120A. Since the mounting portion 124 and the connection electrode 128 are formed on the base plate 120a and the base plate 120b formed on the base wafer W120A at the same place in the base plate, the piezoelectric vibrating piece 130 includes the base plate 120a and the base plate 120a. The base plate 120b can be placed on the placement portion 124 without being discriminated.

  In step S105, the base wafer W120A and the lid wafer W110 are bonded by the bonding material 140. In joining the base wafer W120A and the lid wafer W110, the second surface 122 of the base wafer W120A and the joining surface 112 of the lid wafer W110 are joined to each other via the joining material 140. Thereby, a plurality of piezoelectric devices 100 are formed on the wafer.

  In step S106, the wafer is cut by dicing. The wafer is cut along a scribe line 142 (see FIGS. 5 and 6), and each piezoelectric device 100 formed on the wafer is individually divided.

<Modification of base plate>
Various modifications of the base plate and the base wafer with different castellations and through hole shapes are possible. Hereinafter, modifications of the base plate and the base wafer will be described.

  FIG. 7A is a partial plan view of the base wafer W120B. In the base wafer W120B, a plurality of base plates 120c and a plurality of base plates 120d are alternately formed in the X-axis direction and the Z′-axis direction. FIG. 7A shows a scribe line 142, and each base plate 120 c and base plate 120 d are surrounded by the scribe line 142. Further, through holes 143 c and through holes 143 d are alternately formed at the intersections of the scribe lines 142 extending in the X-axis direction and the scribe lines 142 extending in the Z′-axis direction. A through hole 143c is formed at a corner of the base plate 120c on the + Z ′ axis side on the + X axis side, and a through hole 143d is formed at a corner of the base plate 120d on the + Z ′ axis side of the + X axis side. The through hole 143c extends from the intersection of the scribe lines 142 in the + X-axis direction and the + Z′-axis direction, and extends in the −X-axis direction and the −Z′-axis direction. The through hole 143d extends short from the intersection of the scribe lines 142 in the + X-axis direction and the + Z′-axis direction, and extends long in the −X-axis direction and the −Z′-axis direction.

  FIG. 7B is a plan view of the base plate 120c. The castellation 27a of the base plate 120c extends by a length LZ1 in the + Z′-axis direction and a length LX1 in the −X-axis direction. The castellation 27d extends by a length LZ2 in the −Z′-axis direction and a length LX2 in the + X-axis direction. The castellation 27b extends by a length LX2 and a length LZ1 in the −X axis direction and the −Z ′ axis direction, respectively. The castellation 27c extends by a length LX1 and a length LZ2 in the + X axis direction and the + Z ′ axis direction, respectively. Yes. In the base plate 120c, the length LX1 is equal to the length LZ2, and the length LZ1 is equal to the length LX2. Further, the length LZ1 is shorter than the length LX1. Therefore, the straight line 171 connecting the corner portion 171a of the castellation 27a and the corner portion 171b of the castellation 27b, and the straight line 172 connecting the corner portion 172a of the castellation 27a and the corner portion 172c of the castellation 27c are both X-axis. And not parallel to the Z ′ axis.

  FIG. 7C is a plan view of the base plate 120d. The castellation 27a of the base plate 120d extends by a length LZ2 in the + Z′-axis direction and a length LX2 in the −X-axis direction. The castellation 27d extends by a length LZ1 in the −Z′-axis direction and a length LX1 in the + X-axis direction. The castellation 27b extends by a length LX1 and a length LZ2 in the −X axis direction and the −Z ′ axis direction, respectively. The castellation 27c extends by a length LX2 and a length LZ1 in the + X axis direction and the + Z ′ axis direction, respectively. Yes. In the base plate 120d, the length LX1 is equal to the length LZ2, and the length LZ1 is equal to the length LX2. Further, the length LZ1 is shorter than the length LX1. Therefore, the straight line 171 connecting the corner portion 171a of the castellation 27a and the corner portion 171b of the castellation 27b, and the straight line 172 connecting the corner portion 172a of the castellation 27a and the corner portion 172c of the castellation 27c are both X-axis. And not parallel to the Z ′ axis.

  FIG. 8A is a partial plan view of the base wafer W120C. In the base wafer W120C, a plurality of base plates 120e and a plurality of base plates 120f are alternately formed in the X-axis direction and the Z′-axis direction. FIG. 8A shows a scribe line 142, and each base plate 120 e and base plate 120 f are surrounded by the scribe line 142. Further, through holes 143e and through holes 143f are alternately formed at the intersections of the scribe lines 142 extending in the X-axis direction and the scribe lines 142 extending in the Z′-axis direction. A through hole 143e is formed at a corner of the base plate 120e on the + Z-axis side on the + X-axis side, and a through-hole 143f is formed at a corner on the + Z-axis side of the base plate 120f on the + Z-axis side. The through hole 143e extends from the intersection of the scribe line 142 in the + Z′-axis direction and the −Z′-axis direction. Further, the through hole 143f extends shortly from the intersection of the scribe line 142 in the + X axis direction and the −X axis direction.

  FIG. 8B is a plan view of the base plate 120e. The castellation 27a of the base plate 120e extends by a length LX1 in the −X axis direction. Further, the castellation 27d extends by a length LX1 in the + X-axis direction. The castellation 27b and the castellation 27c extend by a length LZ2 in the −Z′-axis direction and the + Z′-axis direction, respectively. In the base plate 120e, the length LX1 and the length LZ2 are equal. Further, in the base plate 120e, a straight line 171 connecting the corner portion 171a of the castellation 27a and the corner portion 171b of the castellation 27b, and a straight line 172 connecting the corner portion 171a of the castellation 27a and the corner portion 172c of the castellation 27c, Are not both parallel to the X and Z ′ axes.

  FIG. 8C is a plan view of the base plate 120f. The castellation 27a and the castellation 27d of the base plate 120f extend by the length LZ2 in the + Z′-axis direction and the −Z′-axis direction, respectively. Further, the castellation 27b and the castellation 27c extend by a length LX1 in the −X axis direction and the + X axis direction, respectively. Therefore, the straight line 171 connecting the corner 171a of the castellation 27a and the corner 171b of the castellation 27b and the straight line 172 connecting the corner 171a of the castellation 27a and the corner 172c of the castellation 27c are both X-axis. And not parallel to the Z ′ axis.

  FIG. 9A is a partial plan view of the base wafer W120D. On the base wafer W120D, a plurality of base plates 120g and a plurality of base plates 120h are alternately formed in the X-axis direction. On the other hand, the plurality of base plates 120g and the plurality of base plates 120h are formed by arranging the same type of base plates in the Z′-axis direction. FIG. 9A shows a scribe line 142, and each base plate 120 g and the base plate 120 h are surrounded by the scribe line 142. A through hole 143g and a through hole 143h are formed at the intersection of the scribe line 142 extending in the X-axis direction and the scribe line 142 extending in the Z′-axis direction, and alternately in the Z′-axis direction in the X-axis direction. Are formed with the same through-hole. A through hole 143g is formed at the corner of the base plate 120g on the + Z-axis side on the + X-axis side, and a through-hole 143h is formed at a corner on the + Z-axis side of the base plate 120h on the + Z-axis side. . The through-hole 143g extends from the intersection of the scribe lines 142 in the + Z′-axis direction, and the through-hole 143h extends from the intersection of the scribe lines 142 in the −Z′-axis direction. The base plate 120g is formed in a shape in which the castellation 27b and the castellation 27c of the base plate 120f shown in FIG. 8C are not formed. Further, unlike the base plate 120g, the placement portion 124 of the base plate 120h is formed on the + Z′-axis side on the + X-axis side and the −Z′-axis side on the −X-axis side of the recess 123. Since the base plate 120h has the lead electrode 132 formed along the + X-axis side and the -X-axis side of the piezoelectric vibrating piece 130, when the piezoelectric vibrating piece 130 is placed on the base plate, the base plate 120h And the base plate 120g need not be distinguished.

  FIG. 9B is a partial plan view of the base wafer W120E. In the base wafer W120E, a plurality of base plates 120j and a plurality of base plates 120k are alternately formed in the X-axis direction and the Z′-axis direction. FIG. 9B shows a scribe line 142, and each base plate 120 j and the base plate 120 k are surrounded by the scribe line 142. Further, every other through-hole 143j is formed at the intersection of the scribe line 142 extending in the X-axis direction and the scribe line 142 extending in the Z′-axis direction in the X-axis direction and the Z′-axis direction. The through hole 143j extends from the intersection of the scribe line 142 in the + Z′-axis direction and the −Z′-axis direction. The shape of the base plate 120j is the same as the base plate 120h in FIG. 9A, and the shape of the base plate 120k is the same as the base plate 120g in FIG. 9A.

  FIG. 9C is a partial plan view of the base wafer W120F. In the base wafer W120F, a plurality of base plates 120m and a plurality of base plates 120n are alternately formed in the X-axis direction and the Z′-axis direction. FIG. 9C shows a scribe line 142, and each base plate 120 m and the base plate 120 n are surrounded by the scribe line 142. Further, every other through-hole 143k is formed at the intersection of the scribe line 142 extending in the X-axis direction and the scribe line 142 extending in the Z′-axis direction in the X-axis direction and the Z′-axis direction. The through hole 143k extends from the intersection of the scribe line 142 at equal distances in the + Z′-axis direction, the −Z′-axis direction, the + X-axis direction, and the −X-axis direction. The base plate 120m and the base plate 120n are formed by extending grooves in a pair of castellations on a diagonal line in the X-axis direction and the Z′-axis direction.

  In each of the base plates shown in FIGS. 9A, 9B, and 9C, castellations are formed at the corners of the base plate on one diagonal, but on the other diagonal. No castellations are formed at the corners of the base plate. Since the earth terminal formed on the surface on the −Y ′ axis side is not necessarily electrically connected to the side electrode formed in the castellation, it is shown in FIGS. 9A to 9C. As described above, the castellation can be formed only at a position in contact with the external electrode. In such a case, since the castellations adjacent to each other in the X-axis direction and the Z′-axis direction are not formed, the corner portions of the castellations adjacent to each other in the X-axis direction and the Z′-axis direction are connected to each other and pass near the center of the base plate. A straight line is not formed, and the base plate is hardly cracked.

(Second Embodiment)
As the piezoelectric device, a piezoelectric vibrating piece having an outer frame may be used. Hereinafter, the piezoelectric device 200 having the piezoelectric vibrating piece in which the outer frame is formed will be described.

<Configuration of Piezoelectric Device 200>
FIG. 10 is an exploded perspective view of the piezoelectric device 200. The piezoelectric device 200 mainly includes a lid plate 210, a base plate 220a, and a piezoelectric vibrating piece 230a. The piezoelectric vibrating piece 230a includes a vibrating portion 233 having excitation electrodes 231 formed on surfaces on the + Y ′ axis side and the −Y ′ axis side, a frame portion 234 that surrounds the excitation portion 233, and the vibrating portion 233 and the frame portion 234, respectively. And a connecting portion 235 to be connected. A through groove 236 that penetrates the piezoelectric vibrating piece 230 a in the Y′-axis direction is formed in a region other than the connecting portion 235 between the vibrating portion 233 and the frame portion 234. From the excitation electrode 231 formed on the surface on the + Y′-axis side, the + Z′-axis on the −X-axis side of the frame portion 234 through the connecting portion 235 and the side surface of the through-groove 236 on the + Z′-axis side on the −X-axis side The extraction electrode 232 is extracted to the corner of the surface on the −Y ′ axis side. Further, from the excitation electrode 231 formed on the surface on the −Y′-axis side, the corner portion of the surface on the −Y′-axis side on the −Z′-axis side on the −Z′-axis side of the + X-axis side of the frame portion 234 via the connecting portion 235. The extraction electrode 232 has been extracted up to.

  The base plate 220a is disposed on the surface at the −Y′-axis side of the piezoelectric vibrating piece 230a. An external electrode 225 and a ground terminal 226 are formed on the first surface 221 that is the surface on the −Y′-axis side of the base plate 220 a. Further, a recess 223 and a second surface 222 around the recess 223 are formed on the surface at the + Y′-axis side. Further, connection electrodes 228 are formed at the corners of the second surface 222 on the + Z-axis side on the + X-axis side and on the + Z′-axis side on the −X-axis side. Further, castellations 227 are formed at corners of the base plate 220a on the + Z-axis side on the + X-axis side and on the + Z-axis side on the -X-axis side, and side electrodes 229 are formed on the castellation 227. The side electrode 229 is electrically connected to the connection electrode 228 and the external electrode 225. The base plate 220a and the piezoelectric vibrating piece 230a are bonded to each other via the bonding material 140 (see FIG. 11) between the second surface 222 of the base plate 220a and the surface on the −Y′-axis side of the frame portion 234 of the piezoelectric vibrating piece 230a. To be joined.

  The lid plate 210 is disposed on the surface at the + Y′-axis side of the piezoelectric vibrating piece 230a. A recess 211 is formed on the −Y′-axis side of the lid plate 210, and a bonding surface 212 is formed so as to surround the recess 211. The lid plate 210 and the piezoelectric vibrating piece 230a are bonded to the bonding surface 212 of the lid plate 210 and the surface on the + Y′-axis side of the frame portion 234 of the piezoelectric vibrating piece 230a via a bonding material 140 (see FIG. 11). Are joined.

  Fig.11 (a) is BB sectional drawing of FIG. In the piezoelectric device 200, the base plate 220a, the lid plate 210, and the piezoelectric vibrating piece 230a are joined to each other, whereby a cavity 201 is formed in the piezoelectric device 200. In addition, the piezoelectric vibrating portion 233 of the piezoelectric vibrating piece 230 a is disposed in the cavity 201. The excitation electrode 231 formed on the piezoelectric vibrating portion 233 is electrically connected to the external electrode 225 by electrically connecting the extraction electrode 232 and the connection electrode 228 of the base plate 220a. The castellation 227 of the base plate 220a includes a first curved surface 271 formed extending from the first surface 221 toward the second surface 222, and a first curved surface 271 formed extending from the second surface 222 toward the first surface 221. The second curved surface 272 and the projecting surface 273 formed between the first curved surface 271 and the second curved surface 272 are configured. The first curved surface 271 and the second curved surface 272 include a curved surface in which the cross section in the Y′-axis direction is recessed toward the base plate 220a, and the protruding surface 273 is formed so that the cross-section in the Y′-axis direction is a straight line. . Further, the protruding surface 273 is formed to protrude outward from the base plate 220 with respect to the first curved surface 271 and the second curved surface 272. Side electrodes 229 are formed on the first curved surface 271, the second curved surface 272, and the projecting surface 273, and the side electrode 229 electrically connects the connection electrode 228 and the external electrode 225. The surfaces of the first surface 221, the external electrode 225, and the ground terminal 226 (see FIG. 11C) are formed into a rough surface.

  FIG. 11B is a plan view of the base plate 220a. A recess 223 is formed on the surface of the base plate 220 a on the + Y′-axis side, and a second surface 222 is formed so as to surround the recess 223. A castellation 227 is formed on the −Z′-axis side on the + X-axis side and the + Z′-axis side on the −X-axis side. The cross section of the castellation 227 in the X-Z ′ plane includes a part of a circle having a radius L227, and the side electrode 229 (see FIG. 11A) is formed on the castellation 227. Further, a connection electrode 228 electrically connected to the side surface electrode 229 is formed on the −Z′-axis side on the + X-axis side and the + Z′-axis side on the −X-axis side of the second surface 222.

  FIG. 11C is a plan view of the base plate 220a on which the electrodes on the surface at the −Y′-axis side are shown. In FIG. 11C, the electrode formed on the surface on the −Y′-axis side of the base plate 220a is shown as seen through the base plate 220a in the −Y′-axis direction from the + Y′-axis side. . External electrodes 225 are formed on the −Z′-axis side on the + X-axis side and the + Z′-axis side on the −X-axis side of the surface on the −Y′-axis side of the base plate 220a. Each external electrode 225 is electrically connected to a connection electrode 228 formed on the surface on the + Y′-axis side via a side electrode 229 (see FIG. 11A) formed on the castellation 227. Also, ground terminals 226 are formed on the + Z′-axis side on the + X-axis side and the −Z′-axis side on the −X-axis side of the surface on the −Y′-axis side.

<Method for Manufacturing Piezoelectric Device 200>
FIG. 12 is a flowchart showing a method for manufacturing the piezoelectric device 200. Hereinafter, a method for manufacturing the piezoelectric device 200 will be described with reference to FIG.

  In step S201, a piezoelectric wafer W230 is prepared. A plurality of piezoelectric vibrating pieces 230a and a plurality of piezoelectric vibrating pieces 230b are formed on the piezoelectric wafer W230. Hereinafter, the piezoelectric wafer W230 will be described with reference to FIG.

  FIG. 13 is a plan view of the piezoelectric wafer W230. In FIG. 13, the scribe line 142 is indicated by a two-dot chain line, and the piezoelectric vibrating piece 230 a and the piezoelectric vibrating piece 230 b are surrounded by the scribe line 142. The piezoelectric vibrating pieces 230a and the piezoelectric vibrating pieces 230b are alternately formed in the X-axis direction and the Z′-axis direction. In the piezoelectric vibrating piece 230 b, the connecting portion 235 is formed on the + Z′-axis side on the + X-axis side and the −Z′-axis side on the −X-axis side of the vibrating portion 233, and the extraction electrode 232 is on the + X-axis side of the frame portion 234. Are pulled out to the + Z′-axis side and the −Z′-axis side of the −X-axis side. The piezoelectric vibrating piece 230a and the piezoelectric vibrating piece 230b have shapes that are plane-symmetric with respect to the X-Y ′ plane, and there is no difference in electrical characteristics, vibration characteristics, and the like. In the piezoelectric wafer W230, the through-groove 236, the excitation electrode 231 and the extraction electrode 232 are formed, so that the piezoelectric vibrating piece 230a and the piezoelectric vibrating piece 230b are formed.

  In step S202, a base wafer is prepared. A plurality of base plates are formed on the base wafer. Hereinafter, the base wafer W220A will be described with reference to FIG. 14, and a method for manufacturing the base wafer W220 will be described with reference to FIGS.

  FIG. 14 is a plan view of the base wafer W220A. A plurality of base plates are formed on the base wafer W220A. There are two types of base plates formed on the base wafer W220A, the base plate 220a and the base plate 220b, which are alternately formed in the X-axis direction and the Z′-axis direction, respectively. Further, in FIG. 14, a scribe line 142, which is a line for cutting the wafer in step S106 described later, is indicated by a two-dot chain line. The base plate 220a and the base plate 220b formed on the base wafer W220A are surrounded by the scribe line 142. Further, at positions where the scribe lines 142 extending in the X-axis direction and the scribe lines 142 extending in the Z′-axis direction intersect, every other through-hole 243a that penetrates the base wafer W220A is formed. The planar shape of the through hole 243a is a circle centered on the intersection of the scribe lines 142. The base plate 220a has a through hole 243a disposed on the -Z 'axis side on the + X axis side and the + Z' axis side on the -X axis side, and the base plate 220b has a through hole 243a on the + Z axis side on the + X axis side. And on the −Z′-axis side on the −X-axis side.

<< Preparation Method 1 of Base Wafer W220A >>
FIG. 15 is a flowchart showing a method for manufacturing the base wafer W220A. A diagram for explaining each step is shown on the right side of each step shown in FIGS. 15 and 16. 15 is a cross-sectional view corresponding to the CC cross section of base wafer W220A shown in FIG. A method for manufacturing the base wafer W220A will be described below with reference to FIGS.

  In step S221 of FIG. 15, the corrosion-resistant film 150 and the photoresist 151 are formed on both surfaces of the flat base wafer W220A on the + Y′-axis side and the −Y′-axis side. FIG. 15A shows a partial cross-sectional view of the base wafer W220A on which the corrosion-resistant film 150 and the photoresist 151 are formed. As shown in FIG. 15A, the corrosion resistant film 150 is formed on the surface of the base wafer W220A on the + Y′-axis side and the −Y′-axis side, and the photoresist 151 is formed on the surface of the corrosion-resistant film 150. The corrosion resistant film 150 is formed by forming a metal film on the base wafer W220A by a technique such as sputtering or vapor deposition. The corrosion resistant film 150 is formed, for example, by forming a film of nickel (Ni), chromium (Cr), titanium (Ti), nickel tungsten (NiW) or the like on the base wafer W220A, and gold (Au) and silver on the base. It is formed by depositing (Ag) or the like. The photoresist 151 is uniformly applied to the surface of the corrosion resistant film 150 by a technique such as spin coating.

  In step S222, the photoresist 151 is exposed and developed, and the corrosion resistant film 150 is etched. FIG. 15B shows a cross-sectional view of the base wafer W220A in which the photoresist 151 is exposed and developed and the corrosion-resistant film 150 is etched. In the region where the photoresist 151 is exposed and developed in step S222, the concave region 160 corresponding to the concave portion 223 (see FIG. 14) on the surface on the + Y′-axis side of the base wafer W220, and the through hole 243a on the −Y′-axis side ( 14 and a second through region 162 corresponding to the + Y′-axis side through hole 243a (see FIG. 14).

  In step S223, the base wafer W220A is wet etched. FIG. 15C shows a cross-sectional view of the base wafer W220 after the wet etching. The regions of the base wafer W220A that are wet-etched are the recessed region 160, the first through region 161, and the second through region 162. The base wafer W <b> 220 </ b> A is wet-etched to form a recess 223, and recesses corresponding to the first curved surface 271 and the second curved surface 272 of the castellation 227 are formed in the first through region 161 and the second through region 162. In step S233, the base wafer W220 is etched by the depth HY1, and the base wafer W220A is left without being penetrated 170 between the first through region 161 and the second through region 162 of the base wafer W220A.

  In step S224, the photoresist 151 and the corrosion resistant film 150 formed on the base wafer W220A are removed, and a through hole 243a is formed by sandblasting. FIG. 15D is a cross-sectional view of the base wafer W220A in which the through hole 243a is formed. Sand blasting is performed by spraying abrasive on the surface at the −Y′-axis side of the base wafer W <b> 220 </ b> A in the + Y′-axis direction from the −Y′-axis side. The abrasive that is sprayed onto the base wafer W220A penetrates the space 170 between the first through region 161 and the second through region 162, whereby a projection 273 is formed in the through hole 243a. In addition, the first surface 221 that is the surface on the −Y′-axis side of the base wafer W220 has a rough surface with a larger level difference in surface irregularities than other surfaces of the base wafer W220A such as the second surface 222 of the base wafer W220A. It is formed in a planar shape.

  In step S225, the connection electrode 228, the external electrode 225, the ground terminal 226 (see FIG. 11C), and the side electrode 229 are formed on the base wafer W220A. FIG. 15E is a cross-sectional view of the base wafer W220A on which electrodes are formed. These electrodes are formed, for example, by forming a chromium (Cr) layer on the surface of glass and depositing a gold (Au) layer on the surface of the chromium layer. Further, since the first surface 221 of each base plate 220a and base plate 220b is formed into a rough surface, the surfaces of the external electrode 225 and the ground terminal 226 are also formed into a rough surface.

  In the method for manufacturing the base wafer W220A shown in FIG. 15, the protrusions 273 are formed on the castellations 227 of the base plates 220a and the base plates 220b formed on the base wafer W220A. Since the protrusion 273 is formed on the base plate of the piezoelectric device 200, when the piezoelectric device 200 is mounted on the printed board via the solder, the solder faces the second surface of the base plate via the castellation 227. Access to 222 is blocked. When the solder approaches the second surface 222 of the base plate, it is considered that the sealing of the cavity of the piezoelectric device is broken or weakened by the heat of the solder, but in the piezoelectric device 200, the cavity sealing by the solder is thus performed. It is possible to prevent torn stops. Furthermore, since the surfaces of the external electrode 225 and the ground terminal 226 are also roughened, the surface area of the external electrode 225 and the ground terminal 226 is increased and the bonding area with the solder is increased. Can be joined.

<< Manufacturing Method 2 of Base Wafer W220A >>
The first curved surface of the base plate castellation may be formed larger than the second curved surface. A method for manufacturing a base wafer having a base plate in which the area of the first curved surface is larger than the area of the second curved surface will be described below with reference to FIG. Further, in this manufacturing method, step S221 and step S222 in FIG. 15 are common, and therefore the flowchart shown in FIG. 16 is described as the next step after step S222 in FIG.

  Step S233 in FIG. 16 is the next step after step S222 in FIG. In step S233, the concave region 160, the first through region 161, and the second through region 162 of the base wafer W220A are wet-etched, so that the castellation 227 is formed in the concave portion 223 and the first through region 161 and the second through region 162. Recesses corresponding to the first curved surface 271 and the second curved surface 272 are formed. FIG. 16A is a cross-sectional view of the base wafer W220A subjected to wet etching. Base wafer W220A that is wet-etched in step S233 is etched by depth HY2. This depth HY2 is shallower than the depth HY1 shown in step S223 of FIG.

  In step S234, the corrosion-resistant film 150 and the photoresist 151 on the surface on the + Y′-axis side of the base wafer W220A are removed, and the corrosion-resistant film 150 and the photoresist 151 are formed again on the surface on the + Y′-axis side. FIG. 16B is a cross-sectional view of the base wafer W220A in which the corrosion-resistant film 150 and the photoresist 151 are formed on the entire surface on the + Y′-axis side. In step S234, the corrosion-resistant film 150 and the photoresist 151 are formed on the entire surface of the base wafer W220A on the + Y′-axis side, but the corrosion-resistant film 150 and the photoresist are formed on the first through region 161 on the surface on the −Y′-axis side. 151 is not formed.

  In step S235, the first through region 161 is wet etched. FIG. 16C is a cross-sectional view of the base wafer W220A in which the first through region 161 is wet-etched. The base wafer W <b> 220 </ b> A in the first through region 161 is further wet-etched so that the groove depth in the first through region 161 is HY <b> 3. The depth HY3 is deeper than the depth HY1 and the depth HY2.

  In step S236, the photoresist 151 and the corrosion resistant film 150 formed on the entire surface of the base wafer W220A are removed, and a through hole 243a is formed by sandblasting. FIG. 16D is a cross-sectional view of the base wafer W220A in which the through hole 243a is formed. Sand blasting is performed by spraying abrasive on the surface at the −Y′-axis side of the base wafer W <b> 220 </ b> A in the + Y′-axis direction from the −Y′-axis side. The abrasive sprayed onto the base wafer W220A penetrates 170 (see FIG. 16C) between the first through region 161 and the second through region 162, so that a projection 273 is formed in the through hole 243a. In addition, the first surface 221 which is the surface on the −Y′-axis side of the base wafer W220A is a rough surface having a larger level difference in surface irregularities than other surfaces of the base wafer W220A such as the second surface 222 of the base wafer W220A. It is formed in a planar shape. Further, the width WX1 in the X-axis direction of the first through region 161 of the through hole 243a is formed larger than the width WX2 in the X-axis direction of the second through region 162 of the through hole 243a.

  In step S237, the connection electrode 228, the external electrode 225, the ground terminal 226 (see FIG. 11C), and the side electrode 229 are formed on the base wafer W220A. FIG. 16E shows a cross-sectional view of the base wafer W220A on which electrodes are formed. These electrodes are formed, for example, by forming a chromium (Cr) layer on the surface of glass and depositing a gold (Au) layer on the surface of the chromium layer. Further, since the first surface 221 of each base plate is formed into a rough surface, the surfaces of the external electrode 225 and the ground terminal 226 are also formed into a rough surface.

  In the method for manufacturing the base wafer W220A shown in FIG. 16, the protrusions 273 are formed on the castellations of the base plates formed on the base wafer W220A. Therefore, similarly to the base plate formed by the manufacturing method shown in FIG. 15, the protrusions 273 are formed, so that the solder is caster when the piezoelectric device 200 is mounted on the printed board via the solder. It is prevented from approaching the second surface 222 of the base plate via the ration. The base plate manufactured by the method of FIG. 16 further increases the area of the first curved surface 271 by forming the first through region 161 of the through hole 243a wider, so that the solder is less likely to reach the second surface 222. Become. Further, since the etching amount of the second through region 162 of the through hole 243a is reduced, the width WX2 in the X-axis direction of the second through region 162 can be formed narrow. That is, since the area of the second surface 222 of the base plate can be increased and the application area of the bonding material 140 can be increased, the sealing of the cavity can be further strengthened.

  Returning to FIG. 12, in step S203, a lid wafer is prepared. A plurality of lid plates 210 are formed on the lid wafer. The lid wafer is formed by forming the concave portion 211 on the surface at the −Y′-axis side in the same manner as the lid wafer W <b> 110 shown in FIG. 6.

  In step S204, the base wafer W220A and the piezoelectric wafer W230 are bonded. Bonding of the base wafer W220A and the piezoelectric wafer W230 is performed such that the piezoelectric vibrating piece 230a and the base plate 220a overlap, and the piezoelectric vibrating piece 230b and the base plate 220b overlap.

  In step S <b> 205, the piezoelectric wafer W <b> 230 and the lid wafer are bonded by the bonding material 140. In bonding the piezoelectric wafer W230 and the lid wafer, the surface on the + Y′-axis side of the piezoelectric wafer W230 and the bonding surface 212 of the lid wafer W210 are bonded to each other via the bonding material 140.

  In step S206, the wafer is cut by dicing. The wafer is cut along a scribe line 142 (see FIGS. 5 and 6), and each piezoelectric device 200 formed on the wafer is individually divided.

<Modification of base plate and base wafer>
Various modifications of the base plate and the base wafer with different castellations and through hole shapes are possible. Hereinafter, modifications of the base plate and the base wafer will be described.

  FIG. 17A is a plan view of the base wafer W220B. In the base wafer W220B, a plurality of base plates 220c and a plurality of base plates 220d are alternately formed in the X-axis direction and the Z′-axis direction. FIG. 17A shows a scribe line 142, and each base plate 220 c and base plate 220 d are surrounded by the scribe line 142. Further, through holes 243 a and through holes 243 b are alternately formed at the intersections of the scribe lines 142 extending in the X-axis direction and the scribe lines 142 extending in the Z′-axis direction. The through hole 243a is formed at the corner of the base plate 220c on the + Z axis side on the + X axis side and the corner of the base plate 220d on the + Z axis side of the + X axis side, and around the through hole 243a. A connection electrode 228 is formed. The through hole 243b is formed to have a smaller radius than the through hole 243a. Side electrodes 229 are formed in the through holes 243a and the through holes 243b.

  FIG. 17B is a plan view of the base plate 220c. The castellation 27a and the castellation 27d of the base plate 220c are part of a circle with a radius L227, and the castellation 27b and the castellation 27c are part of a circle with a radius L227b. Since the radius L227 is larger than the radius L227b, it is difficult for the base plate 220c to receive stress parallel to the X-axis or Z′-axis between the castellations adjacent in the X-axis direction or the Z′-axis direction. It is hard to crack.

  FIG. 17C is a plan view of the base plate 220c showing the electrodes on the surface at the −Y′-axis side. In FIG. 17C, the electrode formed on the surface on the −Y′-axis side is seen through the base plate 220 c from the + Y′-axis side to the −Y′-axis side. External electrodes 225 are formed on the −Z′-axis side on the + X-axis side and the + Z′-axis side on the −X-axis side of the surface on the −Y′-axis side of the base plate 220c. Each external electrode 225 is electrically connected to a connection electrode 228 formed on the surface on the + Y′-axis side via a side electrode 229 formed in the castellation. Further, ground terminals 226 are formed on the + Z′-axis side on the + X-axis side of the surface on the −Y′-axis side and on the −Z′-axis side on the −X-axis side, and are electrically connected to the side electrode 229. ing.

  The base plate 220d is formed symmetrically with respect to the base plate 220c and the X-Y ′ plane. The base plate 220c and the base plate 220d are formed with the side electrode 229 connected to the ground terminal 226, so that when the piezoelectric device is connected to a printed circuit board or the like via solder, the solder is used as the side electrode 229. Therefore, the state of the solder joined to the ground terminal 226 can be confirmed.

  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 embodiment, the external electrode and the ground terminal are formed on the base plate, but only the external electrode may be formed.

  Also, in the above embodiment, the case where the piezoelectric vibrating piece is an AT-cut quartz vibrating piece is shown, but the same applies to a BT cut that vibrates in the thickness-slip mode or a tuning-fork type quartz vibrating piece. Applicable. Further, the piezoelectric vibrating piece can be basically applied not only to a crystal material but also to a piezoelectric material including lithium tantalate, lithium niobate, or piezoelectric ceramic.

DESCRIPTION OF SYMBOLS 100, 200 ... Piezoelectric device 110, 210 ... Lid board 111, 123, 211, 223 ... Recessed part 112, 212 ... Joining surface 120a-120h, 120j-120n, 220a, 220b ... Base board 121, 221 ... 1st surface 122, 222 ... Second surface 124 ... Placement part 125 ... External electrode 126 ... Earth terminal 27a, 27b, 27c, 27d, 127, 227 ... Castellation 128 ... Connection electrode 129 ... Side electrode 130, 230a, 230b ... Piezoelectric vibrating piece 131 ... Excitation electrodes 132, 132a ... Extraction electrodes 140 ... Joint material 141 ... Conductive adhesive 142 ... Scribe lines 143a to 143h, 143j to 143k ... Through holes 150 ... Corrosion resistant film 151 ... Photoresist 233 ... Vibration part 234 ... Frame part 23 ... connecting portion 236 ... through groove

Claims (6)

A piezoelectric device having a rectangular base plate formed by a long side and a short side shorter than the long side and a piezoelectric vibrating piece that vibrates at a predetermined frequency,
The base plate is
A first surface on which a pair of external electrodes are formed;
A second surface on which the piezoelectric vibrating piece is disposed;
A pair of castellations formed on the short side of the one side and recessed inward from a side surface connecting the first surface and the second surface;
The pair of castellations are piezoelectric devices having different lengths in the long side direction. A piezoelectric device having a rectangular base plate formed by a long side and a short side shorter than the long side and a piezoelectric vibrating piece that vibrates at a predetermined frequency,
The base plate is
A first surface on which a pair of external electrodes are formed;
A second surface on which the piezoelectric vibrating piece is disposed;
A pair of castellations formed on the long side of the one side and recessed inward from a side surface connecting the first surface and the second surface;
Piezoelectric devices having different lengths in the short side direction of the pair of castellations. A piezoelectric device having a rectangular base plate having a long side and a short side shorter than the long side and a piezoelectric vibrating piece that vibrates at a predetermined frequency,
The base plate is
A first surface on which a pair of external electrodes are formed;
A second surface on which the piezoelectric vibrating piece is disposed;
A pair of castellations formed in the long side direction and the short side direction at corners where the long side intersects the short side of the one side and recessed inward from the side surface connecting the first surface and the second surface And comprising
Piezoelectric devices having different lengths in the long side direction and lengths in the short side direction of the pair of castellations. The piezoelectric vibrating piece includes a pair of excitation electrodes and a pair of extraction electrodes drawn from the excitation electrodes,
The second surface of the base plate includes a pair of connection electrodes that are electrically connected to the pair of extraction electrodes,
4. The piezoelectric device according to claim 1, wherein the castellation includes a pair of side electrodes that electrically connect the pair of external electrodes and the pair of connection electrodes. 5. A cross section of the castellation includes a first curved surface formed from the first surface to the second surface, a second curved surface formed from the second surface to the first surface, the first surface, and the second surface. It consists of a straight projecting surface formed in the middle of
The piezoelectric device according to claim 4, wherein the side electrode is formed on the first curved surface, the second curved surface, and the protruding surface.   The piezoelectric device according to claim 5, wherein the first curved surface has a larger area than the second curved surface.