Piezoelectric device

Abstract

To provide a piezoelectric device capable of securing reliability and electrical characteristics while reducing stray capacitance inside a package.SOLUTION: A piezoelectric resonator device includes a package having a bottom plate having a rectangular shape in a plan view and a wall portion provided along an edge of the bottom plate, an IC chip mounted in an inner region surrounded by the wall portion, and a piezoelectric resonator connected to a piezoelectric resonator connecting terminal provided on an upper surface of the IC chip, wherein the piezoelectric resonator protrudes from the upper surface of the IC chip toward the wall portion in a plan view, and an excitation electrode included in an electrode pattern formed on the piezoelectric resonator faces only the package in a plan view.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a piezoelectric device in which an integrated circuit chip and a piezoelectric vibrator are mounted. [Background technology]

[0002] Piezoelectric devices are widely used in various electronic devices such as mobile phones and personal computers, mainly for frequency selection and control. Piezoelectric devices can be classified into piezoelectric resonators, piezoelectric oscillators, SAW devices, optical devices, etc., depending on their function. Crystal resonators and crystal oscillators, which use quartz crystal as the piezoelectric element, are widely known and commonly used.

[0003] A crystal oscillator, which is an example of a piezoelectric device, has a structure in which a crystal unit, which is a crystal vibrating piece with electrodes formed thereon, and an integrated circuit (IC) chip are mounted in a single package in order to easily obtain the stable frequency required for information processing, communication processing, etc. The IC chips mounted in such crystal oscillators include those for wire bonding (W / B), which connects the electrode terminals of the IC chip to the electrode terminals of the package via wires, and those for flip chip bonding (FCB), which mounts the IC chip on the electrode terminals of the package via bumps.

[0004] For example, Patent Document 1 discloses a crystal oscillator in which an IC chip is mounted by a W / B. Furthermore, in the crystal oscillator of Patent Document 1, a step is formed in the package, which is the housing, and the IC chip and the crystal resonator element are separately mounted on the housing. In this structure, the IC chip and the crystal resonator element are electrically connected via a wiring pattern formed inside the package. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-220906 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the dimensions of a crystal resonator blank are reduced to meet the recent demand for miniaturization, the amount of frequency variation by voltage control (hereinafter also referred to as VC variation) decreases. Although it has been found that this is due to an increase in the capacitance ratio (γ=C0 / C1) related to the crystal resonator blank caused by stray capacitance due to the wiring pattern formed inside the package, simply reducing the stray capacitance may affect the reliability and electrical characteristics of the crystal oscillator.

[0007] The present disclosure has been made in consideration of such problems, and its purpose is to provide a piezoelectric device that can reduce stray capacitance inside the package while ensuring reliability and electrical characteristics. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, there is provided a piezoelectric device comprising: "a package having a rectangular bottom plate in a planar view and a wall portion provided along the edge of the bottom plate; an IC chip mounted in an inner area surrounded by the wall portion; and a piezoelectric vibrator connected to a piezoelectric vibrator connection terminal provided on the upper surface of the IC chip, wherein the piezoelectric vibrator protrudes from the upper surface of the IC chip toward the wall portion in a planar view; and an excitation electrode included in an electrode pattern formed on the piezoelectric vibrator faces only the package in a planar view." [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a piezoelectric device that can ensure reliability and electrical characteristics while reducing stray capacitance inside the package.

[0010] It should be noted that the above effects are merely examples for the sake of convenience of explanation, and the effects of the present disclosure are not limited to these. In addition to the above effects, the present disclosure can achieve any of the effects described herein. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a crystal oscillator according to an embodiment. [Figure 2] FIG. 2(a) is an end view taken along the dashed line AA in FIG. 1, and FIG. 2(b) is a top view of the crystal oscillator according to the embodiment. [Figure 3] 3(a) is an end view taken along the dashed line BB in FIG. 2(a), and FIG. 3(b) is an end view taken along the dashed line CC in FIG. 2(a). [Figure 4] FIG. 4(a) is a top view of a crystal oscillator according to a first modified example of the embodiment, and FIG. 4(b) is a top view of a crystal oscillator according to a second modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A crystal oscillator, which is an example of a piezoelectric device according to the present disclosure, will be described in detail below with reference to the drawings. The present disclosure is not limited to the content described below and can be modified as desired without departing from the spirit and scope of the present disclosure. The drawings used in the embodiments and their modifications are all schematic representations of the crystal oscillator according to the present disclosure, and may include partial emphasis, enlargement, reduction, or omission to facilitate understanding, and may not accurately represent the scale or shape of each component. Furthermore, some numerical values ​​used in the embodiments and their modifications are merely examples and can be modified as necessary. The same reference symbols are used to designate common components in the drawings.

[0013] (Embodiment) First, the basic structure of a crystal oscillator according to the present disclosure will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of a crystal oscillator according to this embodiment. FIG. 2(a) is an end view taken along dashed line AA in FIG. 1, particularly an end view of the long side of the crystal oscillator. FIG. 2(b) is a top view of the crystal oscillator according to this embodiment, particularly showing the internal structure with a crystal vibrating piece mounted thereon. FIG. 3(a) is an end view taken along dashed line BB in FIG. 2(a), particularly showing the connection between the crystal vibrating piece and the IC chip. FIG. 3(b) is an end view taken along dashed line CC in FIG. 2(a), particularly showing the mounting of the IC chip in the package.

[0014] As can be seen from FIGS. 1 to 3 , a crystal oscillator 1, an example of a piezoelectric device, includes a crystal oscillator package 2 (hereinafter simply referred to as package 2), a crystal vibrating piece 3 and an IC chip 4 mounted in a mounting space 2a of the package 2, and a metal cover (lid) 5 for sealing the mounting space 2a. The crystal oscillator 1 is an electronic component that integrates a crystal vibrating piece 3, an example of a piezoelectric vibrator, and an IC chip 4, which is an oscillator circuit, into a single package. This allows the crystal oscillator 1 to generate a stable frequency and a regular reference signal. In other words, the crystal oscillator 1 includes a crystal resonator as an oscillation element. Note that, in addition to a crystal resonator, the oscillation element may also include, for example, a surface acoustic wave (SAW) resonator, other piezoelectric resonators, or a microelectromechanical systems (MEMS) resonator. In other words, the piezoelectric resonator is not limited to the crystal vibrating piece 3 of this embodiment, but may also be other materials with resonance characteristics (piezoelectric resonators made of ceramics, silicon, etc.), or a piezoelectric vibration substrate or base used in a MEMS resonator or the like.

[0015] The package 2 is a ceramic package formed by laminating multiple ceramics on the surfaces of which desired metal patterns are formed. Specifically, the package 2 has a laminated structure in which a frame-shaped wall portion 11 having an opening of a predetermined size and a bottom plate 12 having a rectangular shape in a plan view are laminated. In particular, the wall portion 11 is provided along the edge of the bottom plate 12. Due to this laminated structure, the package 2 has a mounting space 2a for mounting the crystal vibrating piece 3 and the IC chip 4. Furthermore, an area for mounting the IC chip 4 is formed on the upper surface 12a of the bottom plate 12 in the mounting space 2a, and multiple connection terminals, described below, are provided around the periphery of this area.

[0016] Here, the shape of the package 2 is a rectangular parallelepiped, and is rectangular when viewed from above (FIG. 2(b)). In the following, the thickness direction of the crystal oscillator 1 and the package 2 is referred to as the vertical direction, and the direction perpendicular to the vertical direction is referred to as the horizontal direction. The horizontal direction may also be distinguished as the long side direction (longitudinal direction) and the short side direction (shorter side direction) of the crystal oscillator 1 and the package 2. Furthermore, for each component, the surface located above in the vertical direction may also be referred to as the front surface, and the surface located below may also be referred to as the back surface.

[0017] A sealing conductor pattern 13 is formed on the exposed surface (the surface located on the upper vertical side) of the wall 11 of the package 2. The planar shape of the conductor pattern 13 is frame-like, just like the wall 11. A cover 5 is bonded onto the conductor pattern 13 by known metal bonding. This seals the mounting space 2a of the package, and the mounting space 2a is sealed using a vacuum or a gas such as nitrogen.

[0018] 1 and 2(a), four external connection terminals 20a to 20d are formed at the four corners of the rear surface of the bottom plate 12 of the package 2. Furthermore, as shown in Fig. 2(b), six IC connection pads 21a to 21f are formed on the upper surface 12a of the bottom plate 12, which are electrically connected to electrode terminals (connection terminals) of the IC chip 4. The six IC connection pads 21a to 21f are electrically connected to the corresponding electrode terminals of the IC chip 4 by wire bonding.

[0019] The number of the IC connection pads 21a-21f is not limited to six, and the shape and number of the IC connection pads 21a-21f may be changed as appropriate depending on the type, size, shape, etc. of the IC chip 4. Alternatively, a base having the same height as the IC chip 4 may be provided inside the wall portion 11, and the IC connection pads 21a-21f may be formed on the surface of the base. This makes it possible to align the height of the electrode formation surface of the IC chip 4 and the IC connection pads 21a-21f, thereby improving the accuracy of wire bonding.

[0020] As can be seen from FIGS. 2(a) and 2(b), the IC chip 4 has a rectangular shape in a plan view and an overall rectangular parallelepiped shape. The IC chip 4 is mounted on the top surface 12a of the bottom plate 12 of the package 2 via a fixing member (not shown), such as an adhesive. Furthermore, as shown in FIG. 2(b), six connection terminals 41a-41f, which are electrode terminals, are provided on the top surface 4a of the IC chip 4 (the surface opposite to the surface mounted on the package 2). More specifically, the connection terminals 41a-41f are arranged along each of the long sides of the top surface 4a of the IC chip 4. As can be seen from FIGS. 2(b) and 3(b), the connection terminals 41a-41f are electrically connected to the corresponding IC connection pads 21a-21f by wires W. More specifically, connection terminal 41a is connected to IC connection pad 21a, connection terminal 41b is connected to IC connection pad 21b, connection terminal 41c is connected to IC connection pad 21c, connection terminal 41d is connected to IC connection pad 21d, connection terminal 41e is connected to IC connection pad 21e, and connection terminal 41f is connected to IC connection pad 21f.

[0021] 3(a), two crystal vibrating piece connection terminals 42a and 42b, which are piezoelectric vibrator connection terminals for mounting the crystal vibrating piece 3, are provided on one end of the short side of the top surface 4a of the IC chip 4. A conductive adhesive 18 is applied to the crystal vibrating piece connection terminals 42a and 42b, and the crystal vibrating piece 3 is directly bonded to the IC chip 4 via the conductive adhesive 18. Note that instead of the conductive adhesive 18, the crystal vibrating piece 3 may be directly bonded to the IC chip 4 using a bonding member such as a bump.

[0022] In this way, by directly bonding the crystal vibrating piece 3 onto the IC chip 4, it is possible to significantly reduce the stray capacitance generated in the crystal oscillator 1 compared to bonding the crystal vibrating piece 3 to the connection pads of the package 2. When bonding the crystal vibrating piece 3 to the connection pads of the package, the crystal vibrating piece 3 and the IC chip 4 are electrically connected by the wiring pattern inside the package 2, which generates stray capacitance in the crystal oscillator. However, in the crystal oscillator 1 of this embodiment, there is no such wiring pattern, so the stray capacitance caused by the wiring pattern is eliminated.

[0023] For example, let's assume that the electrode capacitance Ce of the quartz crystal vibrating piece 3 is 1 pF and the series capacitance C1 is 4 pF. If such a quartz crystal vibrating piece 3 is directly mounted on the IC chip 4 as in this embodiment, and the stray capacitance Ch due to the package 2 is assumed to be 0.1 pF, the capacitance ratio γ becomes (Ce + Ch) / C1, or "(1 pF + 0.1 pF) / 4 pF," which is 0.275. On the other hand, if such a quartz crystal vibrating piece 3 is mounted in a package with an internal wiring pattern, and the stray capacitance Ch due to the package 2 is assumed to be 1 pF, the capacitance ratio γ becomes "(1 pF + 1 pF) / 4 pF," which is 0.5. Therefore, in the crystal oscillator 1 of this embodiment, the capacitance ratio γ is reduced to approximately 1 / 2, for example, allowing for an increase in the VC variable amount. As an example of the stray capacitance Ch, it is approximately 0.67 pF in the case of a package of 7.0 mm×5.0 mm size, and approximately 0.14 pF in the case of a package of 2.5 mm×2.0 mm size.

[0024] 2(a) and 2(b), the overall shape of the quartz crystal vibrating piece 3 is a flat plate, and is rectangular in plan view. Electrode patterns 30 are formed on the front and back surfaces of the quartz crystal vibrating piece 3. More specifically, the electrode patterns 30 are composed of excitation electrodes 31, pad electrodes 32 located above the conductive adhesive 18, and connection electrodes 33 connecting the excitation electrodes 31 and the pad electrodes 32. In this embodiment, the electrode patterns 30 on the front surface and the back surface of the quartz crystal vibrating piece 3 are identical in plan view and are formed to face each other and overlap, but this is not limited to this and can be changed as appropriate depending on the characteristics of the quartz crystal unit.

[0025] 2(a) and 2(b), the quartz crystal vibrating piece 3 protrudes from the top surface of the IC chip 4 toward the wall 11 in a plan view. More specifically, in this embodiment, the quartz crystal vibrating piece 3 protrudes along the long side of the bottom plate 12 and is close to the wall 11 located on the short side of the bottom plate 12. The long side of the quartz crystal vibrating piece 3 coincides with the long side of the quartz crystal oscillator 1, and the short side of the quartz crystal vibrating piece 3 also coincides with the short side of the quartz crystal oscillator 1.

[0026] Furthermore, in this embodiment, the excitation electrodes 31 and connection electrodes 33 included in the electrode pattern 30 formed on the quartz crystal vibrating piece 3 face the upper surface 12a of the bottom plate 12 of the package 2 in a planar view. In other words, only the pad electrodes 32 included in the electrode pattern 30 formed on the quartz crystal vibrating piece 3 overlap so as to face the IC chip 4 in a planar view, and the excitation electrodes 31 and connection electrodes 33 do not face the IC chip 4.

[0027] This configuration reduces the effect of heat generated by the IC chip 4 on the excitation electrodes 31 and connection electrodes 33, ensuring good oscillation characteristics (i.e., electrical characteristics as a crystal resonator) when power is supplied to the crystal resonator blank 3 on which the electrode pattern 30 is formed. Furthermore, even if the tip of the crystal resonator blank 3 (i.e., the end opposite the end on which the pad electrodes 32 are formed) hangs down vertically depending on the bonding state of the crystal resonator blank 3, the portion of the crystal resonator blank 3 on which the excitation electrodes 31 are formed will not come into contact with the IC chip 4, ensuring the reliability of the crystal resonator blank 3 on which the electrode pattern 30 is formed. Naturally, the tip of the crystal resonator blank 3 is separated from the top surface 12a of the bottom plate 12 of the package 2 by the height of the IC chip 4, and therefore will not come into contact with the top surface 12a of the bottom plate 12 either.

[0028] As described above, the crystal oscillator 1 according to this embodiment can reduce the stray capacitance inside the package 2 while ensuring reliability and electrical characteristics.

[0029] (Variation) In the above embodiment, the quartz crystal vibrating piece 3 protrudes from the top surface 4a of the IC chip 4 along the long side of the package 2 and is positioned close to the short side of the wall 11. However, this is not limited to this, and the quartz crystal vibrating piece 3 may protrude in the short side direction and be positioned close to the long side of the wall 11. This case will be described below as Modification 1 with reference to Figure 4(a). Here, Figure 4(a) is a top view of a quartz crystal oscillator 1' according to Modification 1 of the embodiment, and particularly shows the internal structure with the quartz crystal vibrating piece mounted.

[0030] In the first modification, compared to the above embodiment, a rectangular parallelepiped IC chip 50 is mounted at a position displaced from the center of the package 2 in the short side direction. Furthermore, rectangular IC connection pads 22a-22f are formed on the top surface 12a of the bottom plate 12 of the package 2, extending from the wall portion 11 toward the IC chip 50. Furthermore, connection terminals 51a-51f are provided on the top surface 50a of the IC chip 50 on the short side in a plan view. The connection terminals 51a-51f are electrically connected to the corresponding IC connection pads 22a-22f by wires W.

[0031] Additionally, a crystal vibrating piece connection terminal (not shown) is provided on one end of the long side of the top surface 50a of the IC chip 50 in plan view. A conductive adhesive (not shown) is applied to the crystal vibrating piece connection terminal, and the crystal vibrating piece 3 is directly bonded to it via the conductive adhesive. The crystal vibrating piece 3 protrudes from the top surface 50a of the IC chip 50 toward the wall 11 in plan view. More specifically, the crystal vibrating piece 3 protrudes along the short side of the bottom plate 12 and is close to the wall 11 located on the long side of the bottom plate 12.

[0032] In this case, the excitation electrodes 31 and connection electrodes 33 included in the electrode pattern 30 formed on the quartz crystal vibrating piece 3 face the upper surface 12a of the bottom plate 12 of the package 2 in a planar view. In other words, only the pad electrodes 32 included in the electrode pattern 30 formed on the quartz crystal vibrating piece 3 overlap so as to face the IC chip 4 in a planar view, and the excitation electrodes 31 and connection electrodes 33 do not face the IC chip 4.

[0033] As a result of the above, in the crystal oscillator 1' according to the first modification, it is also possible to reduce the stray capacitance inside the package 2 while ensuring reliability and electrical characteristics.

[0034] Next, in the above embodiment, the crystal vibrating piece 3 is mounted with dimensions smaller than the IC chip 4, but the crystal vibrating piece 3 may also be larger. This case will be described below as Modification 2 with reference to FIG. 4(b). Here, FIG. 4(b) is a top view of a crystal oscillator 1'' according to Modification 2 of the embodiment, and particularly shows the internal structure when the crystal vibrating piece is mounted.

[0035] In the second modification, a rectangular parallelepiped IC chip 60 is mounted at a position displaced from the center of the package 2 in the long side direction compared to the above embodiment. Furthermore, rectangular IC connection pads 23a-23f are formed on the top surface 12a of the bottom plate 12 of the package 2, extending from the long side of the wall portion 11 toward the IC chip 60. Furthermore, connection terminals 61a-61f are provided on the top surface 60a of the IC chip 60 on the long side in a plan view. The connection terminals 61a-61f are electrically connected to the corresponding IC connection pads 23a-23f by wires W.

[0036] Additionally, a crystal vibrating piece connection terminal (not shown) is provided on one end of the short side of the top surface 60a of the IC chip 60 in plan view. A conductive adhesive (not shown) is applied to the crystal vibrating piece connection terminal, and the crystal vibrating piece 3 is directly bonded to it via the conductive adhesive. The crystal vibrating piece 3 protrudes from the top surface 60a of the IC chip 60 toward the wall 11 in plan view. More specifically, the crystal vibrating piece 3 protrudes along the long side of the bottom plate 12, and is close to the wall 11 located on the short side of the bottom plate 12, as well as close to the wall 11 located on the long side of the bottom plate 12.

[0037] In this case, the excitation electrodes 31 and connection electrodes 33 included in the electrode pattern 30 formed on the quartz crystal vibrating piece 3 face the upper surface 12a of the bottom plate 12 of the package 2 in a planar view. In other words, only the pad electrodes 32 included in the electrode pattern 30 formed on the quartz crystal vibrating piece 3 overlap so as to face the IC chip 4 in a planar view, and the excitation electrodes 31 and connection electrodes 33 do not face the IC chip 4.

[0038] As a result of the above, in the crystal oscillator 1'' according to the second modification, it is also possible to reduce the stray capacitance inside the package 2 while ensuring reliability and electrical characteristics.

[0039] In the above embodiment, a structure for mounting a wire-bonded IC chip 4 has been described, but a structure for mounting a flip-chip-bonded IC chip may also be used. In such a case, the connection terminals of the IC chip and the crystal resonator blank connection terminals are formed on different surfaces. That is, after flip-chip bonding of the IC chip, the crystal resonator blank connection terminals are located on the exposed surface of the IC chip. In addition, in such a case, the IC connection pads are formed in the area directly below the IC chip.

[0040] In the above embodiment, a flat quartz crystal vibrating piece 3 was mounted, but the shape of the quartz crystal vibrating piece 3 is not limited to a flat plate. For example, a single-frame quartz crystal vibrating piece in which one of the short sides is thicker than the other parts may also be mounted. That is, the quartz crystal vibrating piece 3 may be composed of an excitation portion that contributes to the oscillation frequency, a mesa portion that is thicker than the other parts, and an inclined portion located between the excitation portion and the mesa portion. Even in such a case, the pad electrodes formed on the mesa portion are directly bonded to the quartz crystal vibrating piece connection terminals 42a and 42b of the IC chip 4 via the conductive adhesive 18.

[0041] In the above embodiment, the quartz crystal vibrating piece 3 is bonded to the quartz crystal vibrating piece connection terminals 42a, 42b of the IC chip 4 via the conductive adhesive 18, but this is not limiting. For example, the pad electrodes 32 of the quartz crystal vibrating piece 3 and the quartz crystal vibrating piece connection terminals 42a of the IC chip 4 may be connected by wire bonding. In such a case, the quartz crystal vibrating piece 3 is mounted on the IC chip 4 using an adhesive or the like, and the pad electrodes 32 and the quartz crystal vibrating piece connection terminals 42a are electrically connected via wires. This connection method is also effective when the pad electrodes 32 and the quartz crystal vibrating piece connection terminals 42a cannot be placed close to each other due to the type of IC chip 4.

[0042] In the above embodiment and modified examples, the quartz crystal vibrating piece 3 protrudes along the long or short side of the bottom plate 12, but it may protrude in any direction of 360 degrees from the IC chip 4 in a plan view. For example, the quartz crystal vibrating piece 3 may protrude from the IC chip 4 toward a corner of the wall portion 11. In such a case, the quartz crystal vibrating piece connection terminals 42a, 42b are formed at one of the four corners of the IC chip 4.

[0043] (Embodiments of the present disclosure) A first embodiment of the present disclosure is a crystal oscillator comprising: a package having a rectangular bottom plate in a planar view and a wall portion provided along the edge of the bottom plate; an IC chip mounted in an inner area surrounded by the wall portion; and a crystal vibrating piece connected to a crystal vibrating piece connection terminal provided on the top surface of the IC chip; wherein the crystal vibrating piece protrudes from the top surface of the IC chip toward the wall portion in a planar view; and an excitation electrode included in an electrode pattern formed on the crystal vibrating piece faces only the package in a planar view.

[0044] This crystal oscillator structure reduces the impact of heat generated by the IC chip on the electrode pattern, ensuring good oscillation characteristics by supplying power to the crystal resonator element on which the electrode pattern is formed. Furthermore, even if the tip of the crystal resonator element hangs down vertically depending on the bonding condition of the crystal resonator element, the excitation electrode portion of the crystal resonator element will not come into contact with the IC chip, ensuring the reliability of the crystal resonator element, which is a crystal resonator element on which an electrode pattern is formed. In other words, it is possible to ensure reliability and electrical characteristics while reducing stray capacitance inside the package.

[0045] In a second embodiment of the present disclosure, the quartz crystal resonator element in the first embodiment protrudes along the long side or short side of the bottom plate, thereby ensuring better oscillation characteristics by supplying power to the quartz crystal resonator element on which the electrode pattern is formed, and also ensuring better reliability as a quartz crystal resonator, which is a quartz crystal resonator element on which the electrode pattern is formed.

[0046] A third embodiment of the present disclosure is the first or second embodiment, wherein the package includes IC connection pads on the bottom plate, and the connection terminals of the IC chip are connected to the IC connection pads by wires, thereby ensuring electrical connection between the IC chip and the package and ensuring the reliability and electrical characteristics of the crystal oscillator.

[0047] A fourth embodiment of the present disclosure is any of the first to third embodiments, in which the quartz crystal resonator element is directly bonded to the quartz crystal resonator element connection terminals with adhesive or bumps, thereby reducing stray capacitance between the quartz crystal resonator element and the quartz crystal resonator element connection terminals.

[0048] In a fifth embodiment of the present disclosure, in any of the first to fourth embodiments, only the pad electrodes included in the electrode pattern formed on the quartz crystal vibrating piece face the IC chip in a plan view, thereby reducing the effect of heat generated by the IC chip on the electrode pattern and ensuring good oscillation characteristics by supplying power to the quartz crystal vibrating piece on which the electrode pattern is formed. [Explanation of symbols]

[0049] 1. Crystal oscillator (piezoelectric device) 2 Crystal oscillator package (package) 2a Mounting space 3. Quartz crystal resonator (piezoelectric vibrator) 4 IC chip 4a Top side 5 Cover (lid) 11 Wall 12 Bottom plate 12a Top side 18 Conductive adhesive 21a~21f IC connection pads 30 electrode patterns 31 Excitation electrode 32 Pad electrode 33 Connection electrode 41a~41f Connection terminals 42a, 42b Crystal vibrator piece connection terminal (piezoelectric vibrator connection terminal) W Wire

Claims

1. a package including a bottom plate having a rectangular shape in a plan view and a wall portion provided along an edge of the bottom plate; an IC chip mounted in an inner area surrounded by the wall portion; a piezoelectric vibrator connected to a piezoelectric vibrator connection terminal provided on the upper surface of the IC chip, the piezoelectric vibrator protrudes from the upper surface of the IC chip toward the wall portion in a plan view, A piezoelectric device, characterized in that an excitation electrode included in an electrode pattern formed on the piezoelectric vibrator faces only the package in a plan view.

2. The piezoelectric device according to claim 1 , wherein the piezoelectric vibrator protrudes along a long side or a short side of the bottom plate.

3. the package has IC connection pads on the bottom plate; 2. The piezoelectric device according to claim 1, wherein the connection terminals of the IC chip are connected to the IC connection pads by wires.

4. 2. The piezoelectric device according to claim 1, wherein the piezoelectric vibrator is directly bonded to the piezoelectric vibrator connecting terminal by an adhesive or a bump.

5. 2. The piezoelectric device according to claim 1, wherein only pad electrodes included in the electrode pattern formed on the piezoelectric vibrator face the IC chip in a plan view.

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