CN111669140A - Cover plate and piezoelectric device - Google Patents

Abstract

The invention provides a ceramic cover plate and a piezoelectric device, in which the curvature R of the inner corner is eliminated. The ceramic cover plate of the embodiment comprises a flat plate (11) and a frame body (12). The flat plate (11) has a rectangular shape, includes a first plane (11U) and a second plane (11B) opposite to the first plane, and is formed of ceramic. The frame (12) includes a third plane (12U) overlapping the second plane and a fourth plane (12B) opposite to the third plane, and the outer periphery of the frame has the same shape as the flat plate, includes a rectangular space which can include the piezoelectric sheet and includes the first side and the second side in a plan view, and is formed of ceramic. In the frame, a corner portion where the first side and the second side intersect includes a recessed portion (19A), and the recessed portion (19A) is recessed more toward the outer peripheral side than a virtual intersection where the first side and the second side intersect linearly when viewed from above.

Description

Cover plate and piezoelectric device

Technical Field

The present invention relates to a piezoelectric device and a lid (cap) for the piezoelectric device.

Background

Piezoelectric devices such as piezoelectric filters, piezoelectric vibrators, and piezoelectric oscillators using piezoelectric materials such as crystals are used in a very wide range of fields.

As one of the piezoelectric devices described above, for example, patent document 1 discloses a piezoelectric device including a flat plate-shaped base, a piezoelectric element sealed in the base, and a ceramic cover plate covering the piezoelectric element. When a metal cover plate is used as the cover plate, a flange (flange) for connecting the cover plate to the base is required, and therefore, the shape is increased. In the ceramic cover plate of patent document 1, a metal film is formed on substantially the entire inner peripheral surface of a ceramic substrate from the inside toward the outside of the substrate, thereby improving shielding (shield) performance.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. Hei 9-055638

Disclosure of Invention

[ problems to be solved by the invention ]

Since the ceramic cover plate of patent document 1 is formed from ceramic powder, the curvature R of the inner corner of the ceramic cover plate tends to increase similarly to press molding of a metal cover plate.

Accordingly, the present invention provides a ceramic cover plate in which the curvature R of the inside corner is eliminated. In addition, a piezoelectric device using the ceramic cover plate is provided.

[ means for solving problems ]

The ceramic cover plate of the embodiment includes a flat plate and a frame body. The flat plate is rectangular, includes a first plane and a second plane opposite to the first plane, and is formed of ceramic. The frame body includes a third plane overlapping the second plane and a fourth plane opposite to the third plane, has an outer periphery having the same shape as the flat plate, includes a rectangular space which can include the piezoelectric sheet and includes the first side and the second side in a plan view, and is formed of ceramic. In the frame, a corner portion where the first side and the second side intersect includes a recessed portion that is recessed more toward the outer peripheral side than a virtual intersection point where the first side and the second side intersect linearly in a plan view.

The recess comprises a partial shape of a circle, ellipse or polygon. In addition, the method comprises the following steps: a first metal film formed on the second plane; a second metal film formed on the fourth plane; and a conductive body formed in the at least one recess portion to conduct the first metal film and the second metal film.

The piezoelectric device of the embodiment includes: the ceramic cover plate; a base plate including a fifth plane, a sixth plane opposite to the fifth plane, and a package terminal, the base plate being rectangular in plan view, the fifth plane including a pair of connection bumps on which the piezoelectric sheet is mounted, the package terminal being disposed on the sixth plane and electrically connected to the connection bumps; and a piezoelectric sheet connected with the connection bump.

[ Effect of the invention ]

The ceramic cover plate of the present embodiment is formed by joining a frame body and a flat plate using their respective members. Since the rectangular space of the frame is obtained by punching and the corners of the space correspond to the corners in the ceramic lid plate of the present invention, the corners in the ceramic lid plate of the present embodiment can be formed into a shape having no curvature.

Drawings

Fig. 1 is a perspective view depicting constituent members constituting a piezoelectric device divided into a plurality of layers.

Fig. 2(a) is a plan view of the first base plate as viewed from the normal direction (+ Z-axis direction). Fig. 2(B) is a cross-sectional view of the piezoelectric device at a section B-B of fig. 2 (a).

Fig. 3(a) is a plan view of the first cover plate viewed from the normal direction (-Z-axis direction). Fig. 3(b) is a plan view of the first cover plate. Fig. 3(C) is a sectional view of the first cover plate at the section C-C of fig. 3 (a).

Fig. 4(a) is a plan view of the piezoelectric vibrating piece 40, and fig. 4(B) is a sectional view B-B of fig. 4 (a).

Fig. 5(a) is a plan view of the second cover plate viewed from the normal direction (-Z-axis direction). Fig. 5(b) is a plan view of the second cover plate having a tooth-shaped portion.

Fig. 6 is a flowchart of a method of manufacturing a ceramic cover plate and a piezoelectric device using the cover plate.

Fig. 7(a) shows a first example of a mold used for manufacturing the frame 12 of the cover plate 10. Fig. 7(b) shows a second example of a mold used for manufacturing the frame 12 of the cover plate 10.

Description of the symbols

10: first cover board (cover board)

10A: second cover board (cover board)

10B: third cover board (cover board)

11: roof (Flat)

11B: second plane (lower surface)

11U: first plane (Upper surface)

12: frame plate (frame)

12B: fourth plane (lower surface)

12U: third plane (Upper surface)

13: tooth-shaped part

15. 16, 17: metal film

18: inner peripheral surface

19A, 19B: concave part

30: base plate

31: base plate (Flat)

31B: lower surface

31U: upper surface (surface)

34: external electrode

34E: grounding electrode

35: connecting projection

36. 38: interconnection wiring

37: bonding metal film (bonding metal layer)

40: piezoelectric vibrating piece

41: exciting electrode

43: extraction electrode

49: conductive adhesive

80: ceramic package (Package)

92. 94, 98: die set

93. 95, 99: blade body

100: piezoelectric device

EA: eutectic metal

IS: crossing wire

S611 to S616, S631 to S635, and S651 to S653: step (ii) of

W1, W2: distance between two adjacent plates

W5: width of

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings for explanation are schematically illustrated to the extent that the present invention can be understood, and the size, angle, thickness, and the like are exaggeratedly drawn. In the drawings for explanation, the same components are denoted by the same reference numerals, and explanations thereof may be omitted. The shapes, materials, and the like described in the following embodiments are merely preferable examples within the scope of the embodiments.

[ first embodiment ]

< construction of Package >

First, the package of the first embodiment is explained. Fig. 1 is a diagram depicted in multiple layers for the understanding of the package 80. In fig. 1, piezoelectric elements such as a piezoelectric filter, a piezoelectric resonator, and a piezoelectric oscillator, such as a crystal, are not illustrated. The package 80 of the first embodiment is used as a package of a piezoelectric element, and a package of a piezoelectric vibrator will be described as a representative example.

As shown in fig. 1, the package 80 is formed by laminating a ceramic base plate 30 and a ceramic lid plate 10, the ceramic base plate 30 forming the bottom of the package 80 and being rectangular in plan view, and the ceramic lid plate 10 being rectangular in plan view. The ceramic lid 10 as the first lid includes a flat top plate 11 and a frame plate 12 in a frame shape, and a cavity (cavity) for accommodating the piezoelectric vibrating reed is formed.

The top plate 11 is a rectangular flat plate including a short side and a long side. The top plate 11 includes an upper surface 11U and an opposite lower surface 11B. Moreover, the corners of the rectangular top plate 11 may be chamfered to form tooth-shaped portions. The upper surface 11U of the top plate 11 serves as the upper surface of the package 80. The metal film 15 is formed on the entire lower surface 11B.

The frame plate 12 is a rectangular frame body including a short side and a long side. The frame plate 12 includes an upper surface 12U and an opposite lower surface 12B. Moreover, the corners of the rectangular frame plate 12 may be chamfered in accordance with the corners of the top plate 11 to form tooth-shaped portions. The upper surface 12U of the frame plate 12 is bonded to the metal film 15, and the lower surface 12B is formed with a metal film 17 over the entire surface thereof. On the inner peripheral surface of the frame plate 12, a metal film 16 serving as a conductive body is formed except for the short side on the + Y axis side. The frame 12 has a rectangular space in plan view, which can contain the piezoelectric element. Further, four corners inside the case are formed with recessed portions 19A.

The base plate 30 includes ceramics such as alumina. The base plate 30 is a rectangular flat plate 31 including short and long sides, and includes an upper surface 31U and an opposite lower surface 31B. The coupling projections 35 are formed on the upper surface 31U of the base plate 30. Further, a bonding metal film 37 is formed on the outer periphery of the upper surface 31U of the base plate 30 so as to conform to the shape of the frame 12. The inner corner of the bonding metal film 37 is preferably also shaped to fit the recess 19A. The connection bump 35 is formed at a position further inside than the bonding metal film 37 when viewed from the front surface side (Z-axis direction). The connection bump 35 and the bonding metal film 37 may be formed by, for example, forming a nickel (Ni) plating layer on a metallization layer (metallization layer) including tungsten (W), and further forming a gold (Au) plating layer on the nickel plating layer. The connection bump 35 is formed with a connection wiring 36. Further, a connection wiring 38 is formed on the bonding metal film 37.

A plurality of external electrodes 34 are provided on the outer periphery of the lower surface 31B of the base plate 30. These external electrodes 34 are bonded to each other when the package 80 is packaged on an external printed circuit board not shown. The connection wiring 36 is connected to the external electrode 34, and electrically connects the connection bump 35 to the external electrode 34. The interconnection 38 is connected to one ground electrode (earth electrode)34E among the plurality of external electrodes 34, and electrically connects the bonding metal film 37 to the ground electrode 34E. The metal film 15 of the top plate 11 is electrically connected to the metal film 17 on the lower surface through a conductive body, which is the metal film 16 of the recess 19A of the frame plate 12. The metal film 15 is preferably electrically connected to the ground electrode 34E through the eutectic metal EA, the bonding metal film 37, and the via wiring 38.

Although not described in the first embodiment, when the piezoelectric device is a piezoelectric oscillator or the like, an Integrated Circuit (IC) chip or the like may be disposed on the surface 31U of the base plate 30.

In the first embodiment, the ceramic cover plate 10 and the base plate 30 are joined by the eutectic metal EA. In fig. 1, the eutectic metal EA in a frame shape is depicted as a separate body, but the eutectic metal EA is formed by a method such as printing on at least one of the lower surface 12B of the ceramic cover plate 10 and the bonding metal layer 37 of the base plate 30.

The eutectic metal EA used for bonding the ceramic cover plate 10 and the ceramic base plate 30 may be a eutectic alloy having a melting point higher than that of an alloy (for example, lead-free solder) used for connecting the external electrode 34 to an external substrate of an external electronic device or the like, the melting point being 250 to 280 ℃. The eutectic alloy is preferably, for example, a zinc-aluminum (ZnAl) -based, gold-tin (AuSn) -based or copper-tin (CuSn) -based (having a melting point of 300 ℃.

< construction of piezoelectric device >

Next, the base plate 30 and the piezoelectric device 100 will be described in detail with reference to fig. 2(a) and 2 (b). Fig. 2(a) is a plan view of the base plate 30 viewed from above (+ Z axis direction), with the ceramic cover plate 10 removed. Fig. 2(B) is a cross-sectional view of the piezoelectric device 100 at a section B-B of fig. 2 (a).

As depicted in fig. 2(a), a pair of connection bumps 35 are formed on the + Y-axis side of the upper surface 31U of the base plate 31. One of the connection bumps 35 extends in the-Y axis direction to a through electrode, that is, a communication wiring 36, and the other connection bump 35 is formed in a substantially square shape, and the communication wiring 36 is formed therein. Further, a bonding metal film 37 having a substantially constant width W5 is formed, and the bonding metal film 37 is formed on the outer periphery of the upper surface 31U of the base plate 31. The width W5 of the bonding metal film 37 is the same as the width W5 of the frame 12 of the lid plate 10. The recessed shape of the corner portion is preferably matched with the recessed portion 19A of the corner portion of the lid plate 10. The via wiring 38 as a through electrode electrically connects the bonding metal film 37 to the ground electrode 34E (see fig. 1) which is one external electrode 34. The communication wiring 38 may be formed anywhere as long as it is easily connected to the ground electrode 34E.

As depicted in fig. 2(a) and 2(b), the connection bump 35 is spaced apart from the inner end of the bonding metal film 37 on the short side by a distance W1, and is spaced apart from the inner end of the bonding metal film 37 on the long side by a distance W2. This is because the eutectic metal EA, which is the bonding of the ceramic cover plate 10 and the ceramic base plate 30, leaks out, or is printed out by screen printing or the like, so that the eutectic metal EA and the connection bump 35 are not short-circuited (short). The reason for this is that, when the piezoelectric vibrating reed 40 is mounted by applying the conductive adhesive 49 to the connection bump 35, the conductive adhesive 49 and the eutectic metal EA are not short-circuited (short).

As shown in fig. 2(b), the connection bump 35 that is higher in the + Z axis direction is coated with a conductive adhesive 49. The lead electrode 43 (see fig. 4 a and 4 b) of the piezoelectric vibrating reed 40 is disposed on the conductive adhesive 49.

< construction of cover plate 10 >

Fig. 3(a), 3(b), and 3(c) are views showing the first cover plate 10. Fig. 3(a) is a plan view of the first cover plate 10 viewed from below (-Z-axis direction). Fig. 3(b) is an enlarged view of the corner recessed portion 19A. Fig. 3(C) is a sectional view of the first cap plate 10 at the section C-C of fig. 3 (a).

As shown in fig. 3(a) and 3(c), the top plate 11 is made of ceramic such as alumina. The metal film 15 is formed on the entire lower surface 11B of the top plate 11. The metal film 15 is made of nickel (Ni), tungsten (W), chromium (Cr), tin (Sn), or the like, and is formed by printing, sputtering, evaporation, plating, a combination of these methods, or the like. In the first embodiment, the metal film is not formed on the upper surface 11U of the top plate 11, but the metal film 15 may be formed over the entire upper surface 11U.

The frame plate 12 also includes ceramics such as alumina. As described later, the frame plate 12 is manufactured by punching a portion corresponding to a space including the piezoelectric element, which is rectangular in a plan view, in the second green sheet (greenset) by a die. The width W5 of the frame plate 12 is the same as the width W5 of the bonding metal film 37 formed on the base plate 30.

The lower surface 12B of the frame plate 12 is formed with a metal film 17 over the entire surface thereof. The inner peripheral surface 18 of the frame plate 12 has four surfaces, but the metal film 16 is not formed here. The inner peripheral surface 18 on the + Y axis side is the surface closest to the connection projection 35 (see fig. 1). The metal film 16 may be present on all the inner peripheral surfaces 18, but it is preferable that the metal film is absent only in a partial region close to the connection bump 35 among the inner peripheral surfaces 18 on the + Y axis side. The metal film 16 may be present or absent in the recessed portion 19A at the corner on the + Y-axis side, and the metal film 16 is preferably present in the recessed portion 19A at the corner on the Y-axis side. The metal film 16 of the recess 19A is so-called half via (half via). The metal films 16 and 17 include nickel (Ni), tungsten (W), chromium (Cr), tin (Sn), or the like, and are formed by printing, sputtering, evaporation, plating, a combination of these methods, or the like.

The reason why the metal film 16 is not formed on the inner peripheral surface 18 on the + Y-axis side of the inner peripheral surface of the frame plate 12 is that when the piezoelectric vibrating reed 40 (see fig. 2(a) and 2(b)) is mounted by applying the conductive adhesive 49 to the connection bump 35, the conductive adhesive 49 leaks, and the conductive adhesive 49 and the metal film 16 are not short-circuited (short). Even if the conductive adhesive 49 leaks and contacts the inner peripheral surface 18 of the frame plate 12, the metal film 16 is not present, and therefore, short-circuiting is difficult. On the other hand, in order to ensure electromagnetic shielding of the lid plate 10, it is preferable that the inner peripheral surface 18 has a metal film 16.

As shown in fig. 3(b), the recessed portion 19A at the corner portion is a hexagon when viewed including a line indicated by a dashed line, and it is understood that the recessed portion 19A is a part of the hexagon. The recessed portion 19A IS recessed toward the outer peripheral side as compared with an intersection line IS (an intersection point in fig. 3 b) between the inner peripheral surface 18 extending in the X-axis direction and the inner peripheral surface extending in the Y-axis direction. As described above, when the recessed portions 19A are formed at the four corners of the frame plate 12, the space at the corners of the frame 12 is large, and therefore, the housing space of the piezoelectric element can be enlarged.

< composition of piezoelectric vibrating piece >

Fig. 4(a) is a plan view of the piezoelectric vibrating piece 40 of the first embodiment, and fig. 4(B) is a B-B sectional view of fig. 4 (a). The piezoelectric vibrating reed 40 includes an excitation electrode 41 and a lead electrode 43. The piezoelectric vibrating reed 40 is formed in a rectangular flat plate shape having long sides extending in the Y-axis direction and short sides extending in the X-axis direction.

The excitation electrodes 41 are formed on the principal surface and the back surface (+ Z axis side surfaces) of the piezoelectric vibrating reed 40. The excitation electrodes 41 have the same shape and are formed so as to overlap each other in the Z-axis direction. The excitation electrodes 41 are formed in a rectangular shape or an elliptical shape, not shown, in which the major axis extends in the Y-axis direction and the minor axis extends in the X-axis direction, and the extraction electrodes 43 are respectively extracted from the respective excitation electrodes 41 to the + Y-axis side at both ends of the side of the piezoelectric vibrating reed 40 on the Y-axis side. The lead electrode 43 is bonded to the connection bump 35 with a conductive adhesive or the like.

In fig. 4(b), when the piezoelectric vibrating reed is a crystal vibrating reed such as AT-cut or SC-cut, the vibration frequency of vibration by applying a potential is inversely proportional to the thickness of the crystal piece, and therefore the thickness is determined according to the vibration frequency of the piezoelectric vibrating reed 40. In order to confine the main vibration, one end side and the other end side of the vibrating piece in the Y-axis direction are formed thin. The piezoelectric vibrating reed 40 may be a vibrating reed of other vibration modes than the AT-cut piezoelectric vibrating reed. Instead of the piezoelectric vibrating reed 40, a piezoelectric filter, a tuning fork type angular velocity sensor, or the like may be mounted.

[ second embodiment ]

< construction of cover plate 10A >

Fig. 5(a) is a diagram showing a cover plate 10A as a second cover plate. Fig. 5(a) is a plan view of the cover plate 10A as viewed from below (-Z-axis direction). In fig. 5(a), the same reference numerals as in fig. 3(a) denote the same functions and configurations, and therefore, differences between the second cover plate 10A of the second embodiment and the first cover plate 10 shown in fig. 3(a) will be specifically described.

As shown in fig. 5(a), recessed portions 19B are formed at four inner corners. The recessed portion 19B is an elongated circular arc-shaped recess and is formed by a part of an elongated ellipse. In addition, the metal film 16 is formed in the two recesses 19B on the-Y axis side. As described above, the recess may be a part of a circle or an ellipse instead of a part of a polygon.

[ third embodiment ]

< construction of cover plate 10B >

Fig. 5(B) is a view showing the third cover plate 10B. In fig. 5(B), the same reference numerals as in fig. 5(a) denote the same functions and configurations, and therefore, differences between the third cover plate 10B of the third embodiment and the first cover plate 10 shown in fig. 3(a), 3(B), and 3(c) will be specifically described.

As shown in fig. 5(B), the metal film 16 is also formed in the four recesses 19B. Further, at the outer peripheral corner of the third lid plate 10B of the third embodiment, a tooth portion 13 recessed inward from the outer periphery is formed. Although not shown, when the tooth 13 is provided in the third cover plate 10B as described above, it is preferable that the tooth be provided at the same position in the base plate 30.

< method for manufacturing Package body >

Next, the cover plate and the method for manufacturing the piezoelectric device 100 according to the first to third embodiments will be described with reference to fig. 6. The flowchart is described as a manufacturing method for manufacturing one package and one electronic device, but an original manufacturing method is to manufacture hundreds of packages at the same time.

Steps S611 to S616 are methods of manufacturing the cover plate. A first green sheet having a rectangular shape to be the top plate 11 is produced from a slurry (slurry) containing alumina or the like as a main component (step S611). Further, a second green sheet is produced, which is punched out to correspond to a portion including a space portion of the piezoelectric element, which is rectangular in a plan view (step S612). Next, a metal pattern for the first metal film is printed on at least one surface (the surface that becomes the lower surface 11B when finished) of the first green sheet. Specifically, paste (paste) of tungsten or the like is printed on the first green sheet by a screen printing method (step S613). Further, a metal pattern for the second metal film is printed on one surface (the surface to be the lower surface 12B when completed) of the second green sheet and at least three surfaces of the inner peripheral surface of the frame (step S614). Next, the first green sheet and the second green sheet are accurately stacked, and the first green sheet and the second green sheet are fired (step S615). Next, the exposed tungsten is first subjected to electrolytic nickel plating, and then electrolytic gold plating is performed on the nickel plating (step 616). Next, the processed green sheet is separated into individual cover portions using well-known singulation techniques. This completes the ceramic cover plate 10(10A, 10B).

Next, the production of the base plate 30 will be described. A rectangular green sheet to be the bed plate 30 is produced from the slurry containing alumina or the like as a main component (step S631). The green sheet is filled with paste such as tungsten by leaving via holes for the via wirings 36 and 38 (step S632). Next, paste of tungsten or the like is printed by screen printing on the upper surface of the green sheet at positions corresponding to the connection bumps 35 and the bonding metal layer 37. Further, an external electrode tungsten pattern is printed on the lower surface of the green sheet at a position corresponding to the external electrode 34 (step S633). The green sheet for a mount is fired (step S634), and electrolytic nickel plating is first performed on the exposed tungsten, and then electrolytic gold plating is performed on the nickel plating (step S635). Next, the processed green sheet is divided into individual mounts using well-known singulation techniques. This completes the ceramic base plate 30.

Then, conductive adhesive 49 is applied to connection bump 35 of package 80. Next, the lead electrode 43 of the piezoelectric vibrating reed 40 is placed so as to overlap the connection bump 35 with the conductive adhesive 49 applied, and the piezoelectric vibrating reed 40 is fixed in the cavity of the package 80 by curing the conductive adhesive 49 (step S651). The eutectic metal EA is printed by screen printing on at least one of the lower surface 12B of the cover plate 10 and the bonding metal layer 37 on the upper surface 31U of the base plate 30 (step S652). Then, the cover plate 10 and the base plate 30 are stacked and placed in a reflow oven (reflow oven) to which a temperature above the melting point of the eutectic metal EA is applied. Subsequently, the temperature is returned to room temperature, and the two plates are bonded by the eutectic metal EA (step S653), whereby the piezoelectric device 100 is completed.

As described above, in the first embodiment, the ceramic cover plate 10 and the ceramic base plate 30 are formed separately, and the respective plates are used as needed, so that the shipping quantities of the piezoelectric vibrator and the piezoelectric oscillator (piezoelectric device) can be appropriately handled.

< mold >

The mold used for the production of the second green sheet described in step S612 will be described. Fig. 7(a) shows a first example of a mold used for manufacturing the frame body 12 for the second lid plate 10A described in the second embodiment. First, the green sheet is punched by a die 92, and the die 92 is provided with an elliptical blade body 93 for forming the concave portion 19B. Next, the green sheet perforated by the die 92 is perforated by a die 94, the die 94 being provided with a four-sided blade body 95. In the manner described above, the second green sheet is produced.

Fig. 7(b) shows a second example of a mold used for manufacturing the frame body 12 for the second lid plate 10A described in the second embodiment. In the second example, a second green sheet is produced by one punching operation using a die 98 having a blade 99 similar to the frame 12 for the second cover plate 10A. Although the operation efficiency is superior to that of the first example, the first example is more preferable when the recess 19B is accurately perforated.

Claims (4)

1. A ceramic cover plate comprising:

a rectangular flat plate including a first plane and a second plane opposite to the first plane, and formed of ceramic; and

a frame plate including a third plane overlapping the second plane and a fourth plane opposite to the third plane, having an outer periphery having the same shape as the flat plate, including a rectangular space capable of containing a piezoelectric sheet and including a first side and a second side in a plan view, and being formed of a ceramic; and is

A corner portion where the first side and the second side intersect includes a recessed portion that is recessed more toward the outer peripheral side than a virtual intersection where the first side and the second side intersect linearly in a plan view.

2. The ceramic cover plate of claim 1, wherein

The recess comprises a partial shape of a circle, ellipse or polygon.

3. The ceramic cover plate according to claim 1 or 2, comprising:

a first metal film formed on the second plane;

a second metal film formed on the fourth plane; and

and a conductor formed in at least one of the recesses to electrically connect the first metal film and the second metal film.

4. A piezoelectric device, comprising:

the ceramic lid plate of any one of claims 1 to 3;

a base plate, comprising: a fifth plane including a pair of connection bumps on which the piezoelectric sheet is placed; a sixth plane opposite to the fifth plane; the packaging terminal is arranged on the sixth surface and is electrically connected with the connecting bump; and is rectangular in plan view; and

and the piezoelectric piece is connected with the connecting bump.

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