JP5378917B2 - Quartz vibrating piece and quartz vibrating device - Google Patents

Description

  The present invention particularly relates to a surface-mount type crystal vibrating device and a crystal vibrating piece used in the surface mounted type crystal vibrating device.

  The quartz crystal resonator element is known as a frequency control element, and is incorporated as a frequency and time reference source in an oscillator of various electronic devices. Corresponding to the miniaturization of these various electronic devices, miniaturization is also required for the crystal vibrating device. In addition, a crystal vibrating device as a vibrator for surface mounting is indented in a state in which a crystal vibrating piece and circuit components constituting an oscillation circuit are housed in a recess formed on the upper surface of a package body made of, for example, ceramic. The opening of the part is sealed with a metal lid.

  The quartz crystal resonator element disclosed in Patent Document 1 is a rectangular crystal resonator element having an AT cut. In addition, a pair of excitation electrodes facing each other are formed at the center of the quartz crystal vibrating piece. An extraction electrode is formed from the pair of excitation electrodes to the end of the quartz crystal resonator element.

JP 2008-109538 A

  However, in the quartz crystal resonator element disclosed in Patent Literature 1, when the distance between the excitation electrode and the extraction electrode is short and the extraction electrode is fixed to the container body with the conductive adhesive, the excitation electrode is bonded to the conductive adhesive. Or, the conductive adhesive may flow into the excitation electrode. For this reason, there is a possibility of affecting the vibration characteristics of the crystal resonator.

  The present invention provides a crystal vibrating piece that can prevent the conductive adhesive from adhering to the excitation electrode by chamfering the corner of the extraction electrode, or can prevent the conductive adhesive from flowing into the excitation electrode. With the goal.

  A quartz crystal resonator element according to a first aspect includes a quartz crystal resonator element that vibrates in thickness, a pair of excitation electrodes formed on both surfaces of the quartz crystal oscillator piece, a pair of extraction electrodes that are respectively extracted from the excitation electrodes, and a connection to the extraction electrode And a connection electrode that adheres to the conductive adhesive. The corners of the excitation electrode on the connection electrode side are formed in a round shape in a convex shape.

Further, the connection electrode facing the corner portion of the excitation electrode on the connection electrode side of the quartz crystal resonator element is formed in a concave round shape.
Further, the radius of the corner of the excitation electrode formed in the convex shape is the same as the radius of the connection electrode formed in the concave shape.

The connection electrode facing the corner of the excitation electrode on the connection electrode side is formed in an L shape.
Further, the distance between the round corner of the excitation electrode and the connection electrode is equal to or greater than the length of the extraction electrode.

  A crystal resonator device according to a second aspect includes the crystal resonator element and a package for fixing the crystal resonator element.

  According to the present invention, it is possible to obtain a quartz crystal vibrating piece in which the conductive adhesive does not adhere to the excitation electrode or the area of the excitation electrode can be increased.

FIG. 3 is a cross-sectional view of a crystal resonator 100 that houses a first AT-cut crystal resonator element 10A. FIG. 6A is a plan view on the + Y ′ side of a first AT-cut quartz crystal vibrating piece 10 </ b> A. FIG. 6B is a plan view of the first AT-cut quartz crystal vibrating piece 10 </ b> A on the −Y ′ side. FIG. 6A is a plan view of the second AT-cut quartz crystal vibrating piece 10B on the + Y ′ side. FIG. 6B is a plan view of the second AT-cut quartz crystal vibrating piece 10B on the −Y ′ side. FIG. 6A is a plan view on the + Y ′ side of a third AT-cut quartz crystal vibrating piece 10 </ b> C. FIG. 6B is a plan view of the third AT-cut quartz crystal vibrating piece 10 </ b> C on the −Y ′ side. FIG. 6A is a plan view on the + Y ′ side of a fourth AT-cut quartz crystal vibrating piece 10 </ b> D. FIG. 6B is a plan view of the fourth AT-cut quartz crystal vibrating piece 10D on the −Y ′ side.

(First embodiment)
<Whole structure of the crystal unit 100>
In the first embodiment, a surface mount (SMD) type AT-cut crystal resonator element will be described as an example of the crystal resonator element.
Before describing the AT-cut quartz crystal resonator element, a crystal resonator 100 in which the AT-cut crystal resonator element is accommodated will be described with reference to FIG. FIG. 1 is a cross-sectional view of a crystal resonator 100 that houses a first AT-cut crystal resonator element 10A.

  The first AT-cut quartz crystal vibrating piece 10 </ b> A is an AT-cut quartz crystal vibrating piece 11. The AT cut is a cutting angle in which the main surface (YZ plane) is inclined 35 degrees 15 minutes from the Z axis in the Y axis direction with the X axis as the center with respect to the Y axis of the crystal axis (XYZ). Hereinafter, when expressing the axial direction of the first AT-cut quartz crystal vibrating piece 10A, the inclined new axes are referred to as the X ′ axis, the Y ′ axis, and the Z ′ axis, and these are used.

  As shown in FIG. 1, the crystal unit 100 has a package composed of a base 18, a wall 19, and a lid 20. The package houses and seals the first AT-cut quartz crystal vibrating piece 10A. The base 18 and the wall 19 are made of, for example, a piezoelectric body, ceramic, or glass. The lid 20 is made of a substantially flat metal, for example, an Fe—Ni alloy (42 alloy) or an Fe—Ni—Co alloy (Kovar). The lid 20 is bonded to the wall 19 by a bonding material such as AuSi, AuSn, or AuGe, and the inside of the package is hermetically sealed by a technique such as seam welding with nitrogen gas or vacuum. This is to prevent the excitation electrode housed in the package from changing with time.

  A pedestal 15 is provided on the −Z ′ side of the base 18 so as to contact the base 18 and the wall 19b. The pedestal 15 is also formed of a piezoelectric material, ceramic, glass or the like, like the base 18 and the wall 19. The first AT-cut quartz crystal vibrating piece 10 </ b> A is fixed to the pedestal 15 via the conductive adhesive 16.

  The first AT-cut quartz crystal vibrating piece 10 </ b> A is constituted by a quartz crystal vibrating piece 11, and a pair of excitation electrodes 12 a and 12 b are arranged to face both main surfaces (front and back surfaces) near the center of the quartz crystal vibrating piece 11. A pair of extraction electrodes 13a and 13b (described in FIG. 2) are connected in the −Z′-axis direction of the pair of excitation electrodes 12a and 12b, respectively. Further, a pair of connection electrodes 14a and 14b (explained in FIG. 2) are formed on the pair of extraction electrodes 13a and 13b (explained in FIG. 2) so as to sandwich the end portion on the −Z ′ side of the quartz crystal vibrating piece 11. ing. Here, vibration of several MHz to several hundred MHz is generated by “thickness slip” in which the main surface (front surface) and the main surface (back surface) of the first AT-cut quartz crystal vibrating piece 10A move in opposite directions. For this reason, the thickness of the quartz crystal resonator element 11 and the excitation electrodes 12a and 12b is important. Here, the thickness of the quartz crystal vibrating piece 11 is about 2 μm to 200 μm, and the thickness of the excitation electrode, the extraction electrode, and the connection electrode is 0.1 μm to 1.0 μm.

  The connection electrode 14a (described in FIG. 2) is connected to the external electrode 17a through the conductive adhesive 16 and the connecting portion 21a. Here, the connecting portion 21 a passes between the base 18 and the wall 19 a and is connected to the external electrode 17 a provided on the bottom surface of the base 18. Similarly, the connection electrode 14b is connected to the external electrode 17b through the conductive adhesive 16 and the connecting portion 21b. Here, the connecting portion 21 b passes between the base 18 and the wall 19 b and is connected to the external electrode 17 b provided on the bottom surface of the base 18.

  In FIG. 1, the electronic components constituting the oscillation circuit are not arranged inside the package. However, an electronic component of an oscillation circuit may be provided as a crystal oscillator.

<Configuration of First AT Cut Quartz Vibrating Piece 10A>
Hereinafter, the first AT-cut quartz crystal vibrating piece 10A of the first embodiment will be described with reference to FIG.
FIG. 2 is a plan view of the first AT-cut quartz crystal vibrating piece 10A. FIG. 2A is a plan view of the + Y ′ side (surface) of the first AT-cut quartz crystal vibrating piece 10A. FIG. 2B is a plan view of the −Y ′ side (back surface) of the first AT-cut quartz crystal vibrating piece 10 </ b> A.

  As shown in FIG. 2A, the quartz crystal vibrating piece 11 has a rectangular shape. Since the inside of the package shown in FIG. 1 is also rectangular, the width W1 in the X′-axis direction of the crystal vibrating piece 11 formed in substantially the same shape is about 0.30 mm to 0.50 mm, and the Z′-axis The length H1 in the direction is about 0.40 mm to 0.65 mm.

The first AT-cut quartz crystal vibrating piece 10 </ b> A has substantially rectangular excitation electrodes 12 a and 12 b that match the size of the quartz crystal vibrating piece 11 on both main surfaces (front and back surfaces) of the quartz crystal vibrating piece 11.
As shown in FIG. 2A, the excitation electrode 12a provided on the main surface on the + Y ′ side of the quartz crystal vibrating piece 11 is formed with the extraction electrode 13a extracted on the −X ′ side. The extraction electrode 13a is connected to the connection electrode 14a. The connection electrode 14 a is formed so as to sandwich the end portion on the −Z ′ side of the crystal vibrating piece 11 between the front and back sides. Furthermore, the connection electrode 14a provided on the main surface on the −Y ′ side is joined to the connecting portion 21a (see FIG. 1) by the conductive adhesive 16 (see FIG. 2B).

  The excitation electrode 12a has a chamfered shape with a radius R, that is, a rounded shape, at a corner surrounded by the broken line A1, the broken line A2, and the broken line A3. Here, the width W2 in the X′-axis direction of the excitation electrode 12a is about 0.28 mm to 0.45 mm, the length H2 in the Z′-axis direction is about 0.30 mm to 0.45 mm, and the chamfer radius R is It is about 0.07 mm to 0.10 mm.

  Here, for easy understanding, the excitation region LA1 is drawn smaller than the excitation electrode 12a, but substantially coincides with the outer periphery of the excitation region LA1 and the excitation electrode 12a. The excitation electrode 12b (see the broken line B4 in FIG. 2B) provided on the main surface on the −Y ′ side corresponding to the portion surrounded by the broken line A4 is also chamfered with a convex radius R. Therefore, the excitation area LA1 of the excitation electrode 12a is a rounded rectangle indicated by a one-dot chain line.

  Further, the width W3 in the X′-axis direction of the extraction electrode 13a is about 0.07 mm to 0.10 mm, and the length D in the Z′-axis direction is about 0.05 mm to 0.08 mm. The extraction electrode 13a is connected to the connection electrode 14a. The connection electrode 14a provided on the main surface on the + Y ′ side is configured by a portion surrounded by a broken line A5 and a rectangular portion on the X ′ side. The overall shape is almost “L” shaped. Here, the connection electrode 14a surrounded by the broken line A5 has a shape in which a side toward the excitation electrode 12a is chamfered with a concave radius R, that is, rounded into a concave shape. The connection electrode 14a surrounded by the broken line B5 is formed in order to increase the adhesion area with the conductive adhesive 16. Similarly, the connection electrode 14b surrounded by B6 is also formed to increase the adhesion area with the conductive adhesive 16.

  The width W4 in the X′-axis direction of the connection electrode 14a is about 0.14 mm to 0.20 mm, and the length H3 in the Z′-axis direction is about 0.05 mm to 0.08 mm. The shape of the connection electrode 14a provided on the main surface on the −Y ′ side (see FIG. 2B) is the same as that of the connection electrode 14a provided on the main surface on the + Y ′ side. Similarly, the connection electrode 14b provided on the main surface on the + Y 'side is the same, and a portion surrounded by a broken line A6 has a chamfered shape with a side having a concave radius R toward the excitation electrode 12a.

  The excitation electrode 12b and the like shown in FIG. 2B are the same in size and shape as described in FIG. 2A, and are mirror symmetric. The excitation electrode 12b has a chamfered shape with a radius R instead of a right corner at a corner surrounded by the broken line B1, the broken line B2, and the broken line B3. The connection electrode 14 b provided on the main surface on the −Y ′ side is joined to the connecting portion 21 b (see FIG. 1) by the conductive adhesive 16.

  The distance D from the edge of the corner surrounded by the broken line B4 of the excitation electrode 12b to the chamfered side of the connection electrode 14a is a constant distance over about 90 degrees. The distance D from the edge of the excitation electrode 12b to the chamfered side of the connection electrode 14a is the same as the length D of the extraction electrode 13b in the Z′-axis direction, and is about 0.05 mm to 0.08 mm. The distance D from the edge of the excitation electrode 12b to the chamfered side of the connection electrode 14a may be longer than the length D in the Z′-axis direction of the extraction electrode 13b. For this reason, as shown in FIG. 2B, even when a large amount of the conductive adhesive 16 is applied to the connection electrode 14a and the connection electrode 14b, the conductive adhesive 16 does not contact the excitation electrode 12b. That is, the connection electrode 14a and the excitation electrode 12b are not short-circuited.

  As described above, the distance D from the edge of the excitation electrode 12b to the chamfered side of the connection electrode 14a is increased. Instead of increasing the distance D, the area of the excitation electrode 12b may be increased once. When the area of the excitation electrode 12 (12a, 12b) is increased, it is easy to adjust the frequency characteristics when setting the temperature characteristics.

  Each electrode is preferably composed of gold (Au) having excellent conductivity. In order to make the frequency more stable, it is necessary to heat-treat the first AT-cut quartz crystal vibrating piece 10A in the quartz device manufacturing process. Since gold (Au) has high antioxidation and corrosion resistance and low chemical reactivity, high electrical characteristics can be maintained when the crystal unit 100 is manufactured.

(Second Embodiment)
<Configuration of Second AT Cut Quartz Vibrating Piece 10B>
In the second embodiment, the configuration of the crystal resonator 100 in which the crystal resonator element is accommodated is the same as that of the first embodiment. Therefore, as an example of the crystal resonator element, a surface mount (SMD) type second AT-cut crystal resonator element is used. 10B will be described with reference to FIG.

FIG. 3 is a plan view of the second AT-cut quartz crystal vibrating piece 10B of the second embodiment. FIG. 3A is a plan view of the + Y ′ side (surface) of the second AT-cut quartz crystal vibrating piece 10B. FIG. 3B is a plan view of the second AT-cut quartz crystal vibrating piece 10B on the −Y ′ side (back surface). Also in the second embodiment, the X ′ axis, the Y ′ axis, and the Z ′ axis are used.

  As shown in FIG. 3, the second AT-cut quartz crystal vibrating piece 10B of the second embodiment is different from the first AT-cut quartz crystal vibrating piece 10A only in the configuration of the connection electrodes 24a and 24b. For this reason, the connection electrodes 24a and 24b of the second embodiment will be described below.

  As shown in FIG. 3A, the shape of the portion surrounded by the broken lines A5 and A6 of the connection electrodes 24a and 24b provided on the main surface on the + Y ′ side of the quartz crystal vibrating piece 11 is rectangular. As shown in FIG. 3B, the shape of the portion surrounded by the broken lines B5 and B6 of the connection electrodes 24a and 24b provided on the main surface on the −Y ′ side of the crystal vibrating piece 11 is also rectangular. . Accordingly, the overall shape of the connection electrodes 24a and 24b is an “L” shape. Here, the width W5 in the X′-axis direction of the connection electrode 24 surrounded by the broken line A5, the broken line A6, the broken line B5, and the broken line B6 is about 0.05 mm to 0.08 mm. The connection electrode 24a surrounded by the broken line B5 is formed in order to increase the adhesion area with the conductive adhesive 16. Similarly, the connection electrode 24b surrounded by B6 is also formed to increase the adhesion area with the conductive adhesive 16.

  The minimum distance D from the end point K of the portion surrounded by the broken line B5 of the connection electrode 24a shown in FIG. 3B to the excitation electrode 12b is the same as the length D of the extraction electrode 13b in the Z′-axis direction, It is about 0.05 mm to 0.08 mm. For this reason, as shown in FIG. 3B, even when a large amount of the conductive adhesive 16 is applied to the connection electrode 24a and the connection electrode 24b, the conductive adhesive 16 does not contact the excitation electrode 12b. That is, the connection electrode 24a and the excitation electrode 12b do not short-circuit.

(Third embodiment)
<Configuration of Third AT Cut Quartz Vibrating Piece 10C>
In the third embodiment, since the configuration of the crystal resonator 100 in which the crystal resonator element is accommodated is the same as that of the first embodiment, a surface mount (SMD) type third AT-cut crystal resonator element is an example of the crystal resonator element. 10C will be described with reference to FIG.

  FIG. 4 is a plan view of a third AT-cut quartz crystal vibrating piece 10C. FIG. 4A is a plan view on the + Y ′ side of the third AT-cut quartz crystal vibrating piece 10 </ b> C. FIG. 4B is a plan view of the third AT-cut quartz crystal vibrating piece 10C on the −Y ′ side. Also in the third embodiment, the X ′ axis, the Y ′ axis, and the Z ′ axis are used.

  As shown in FIG. 4, the third AT-cut quartz crystal vibrating piece 10C is different from the first AT-cut quartz crystal vibrating piece 10A only in the configuration of the excitation electrodes 32a and 32b. For this reason, the excitation electrodes 32a and 32b of the third embodiment will be described below, and the description of other configurations will be omitted.

  In the excitation electrodes 32 a and 32 b, the excitation electrodes 32 a and 32 b are provided on the corner surrounded by the broken line A 1 and the broken line A 2 provided on the main surface on the + Y ′ side of the crystal vibrating piece 11 or on the −Y ′ side main surface of the crystal vibrating piece 11. The corners surrounded by the broken lines B1 and B2 are not chamfered and have a right angle. The corner surrounded by the broken line A3 on the + Y ′ side is chamfered, and the corner surrounded by the broken line B4 on the −Y ′ side is chamfered.

  For this reason, the shape of the excitation area LA2 also expands with the expansion of the excitation electrodes 32a and 32b. When the area of the excitation electrode 32 (32a, 32b) is increased, it is easy to adjust the frequency characteristics when setting the temperature characteristics.

  As shown in FIG. 4B, the distance D from the edge of the corner surrounded by the broken line B4 of the excitation electrode 32b to the chamfered side of the connection electrode 14a is a constant distance over about 90 degrees. . The distance D from the corner edge to the chamfered side of the connection electrode 14a is the same as the length D in the Z'-axis direction of the extraction electrode 13b, and is about 0.05 mm to 0.08 mm. For this reason, even when a large amount of the conductive adhesive 16 is applied to the connection electrode 14a and the connection electrode 14b, the conductive adhesive 16 does not contact the excitation electrode 32b. That is, the connection electrode 14a and the excitation electrode 32b do not short-circuit.

(Fourth embodiment)
<Configuration of Fourth AT Cut Quartz Vibrating Piece 10D>
In the fourth embodiment, since the configuration of the crystal resonator 100 in which the crystal resonator element is accommodated is the same as that of the first embodiment, a surface mount (SMD) type fourth AT-cut crystal resonator element is an example of the crystal resonator element. 10D will be described with reference to FIG.

  FIG. 5 is a plan view of a fourth AT-cut quartz crystal vibrating piece 10D. FIG. 5A is a plan view on the + Y ′ side of the fourth AT-cut quartz crystal vibrating piece 10 </ b> D. FIG. 5B is a plan view of the fourth AT-cut quartz crystal vibrating piece 10D on the −Y ′ side. Also in the fourth embodiment, the X ′ axis, the Y ′ axis, and the Z ′ axis are used.

As shown in FIG. 5, the fourth AT-cut quartz crystal vibrating piece 10D differs from the third AT-cut quartz crystal vibrating piece 10C only in the configuration of the connection electrodes 24a and 24b. However, the configuration of the connection electrodes 24a and 24b is the same as in the second embodiment.
Also in the fourth embodiment, the contact area between the connection electrodes 24a and 24b and the conductive adhesive 16 increases if the shape of the connection electrodes 24a and 24b is an “L” shape.

  Further, the minimum distance D from the end point K of the portion surrounded by the broken line B5 of the connection electrode 24a shown in FIG. 5B to the excitation electrode 32b is the same as the length D of the extraction electrode 13b in the Z′-axis direction. Yes, about 0.05 mm to 0.08 mm. Therefore, as shown in FIG. 5B, even when a large amount of the conductive adhesive 16 is applied to the connection electrode 24a and the connection electrode 24b, the conductive adhesive 16 does not contact the excitation electrode 32b. That is, the connection electrode 24a and the excitation electrode 32b are not short-circuited.

  Thus, the distance D from the edge of the excitation electrode 32b to the chamfered side of the connection electrode 24a has increased, but instead of increasing the distance D, the area of the excitation electrode 32b may be increased by one.

  The optimum embodiment of the present invention has been described in detail above. 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 present invention, the AT-cut quartz crystal resonator element has been described as an example. However, the present invention is not limited to this, and the same effects as those of the present invention can be obtained by using a BT-cut quartz crystal oscillator, an SC-cut quartz crystal oscillator, or the like. The shape of the excitation electrode is not limited to the rounded rectangle shown in the embodiment of the present invention, and may be variously deformed and may be a rectangle such as a hexagon with rounded corners. Further, the material constituting the excitation electrode and the extraction electrode is not limited to the metal shown in the embodiment of the present invention, but may be a metal such as aluminum (Al), or the content of gold (Au) is 1 to 40 wt. % Gold (Au) silver (Ag) alloy. Furthermore, the quartz crystal vibrating piece can be applied to a quartz vibrating piece called an inverted mesa type having a thick outer portion and a thin inner excitation region.

10A, 10B, 10C, 10D ... AT-cut crystal vibrating piece 11 ... Crystal vibrating piece 12 (12a, 12b) 32 (32a, 32b) ... Excitation electrode 13 (13a, 13b) ... Extraction electrode 14 (14a, 14b), 24 (24a, 24b) ... Connection electrode 15 ... Base 16 ... Conductive adhesive 17a, 17b ... External electrode 18 ... Base 19a, 19b ... Wall 20 ... Lid 21 ... Connection part LA1, LA2 ... Excitation region 100 ... Crystal vibration Child D ... Length of extraction electrode in Z 'direction W1 ... Width of crystal vibrating piece in X' direction W2 ... Width of excitation electrode in X 'direction W3 ... Width of extraction electrode in X' direction W4 ... X 'of connection electrode Width in direction W5 ... Minimum width in the X 'direction of the connection electrode of the second and fourth embodiments H1 ... Length in the Z' direction of the crystal vibrating piece H2 ... Length in the Z 'direction of the excitation electrode H3 ... Minimum length in Z 'direction

Claims (5)

A quartz crystal vibrating piece that vibrates in thickness, a pair of excitation electrodes formed on both surfaces of the quartz crystal vibrating piece, a pair of extraction electrodes respectively drawn from the excitation electrode, and a conductive adhesive connected to the extraction electrode; A quartz crystal resonator element having a connection electrode to be bonded;
The corner of the excitation electrode on the side of the connection electrode is formed in a convex round shape ,
The connection electrode facing the corner portion of the excitation electrode on the connection electrode side is a quartz crystal vibrating piece that is formed in a concave round shape . 2. The quartz crystal resonator element according to claim 1 , wherein a radius of a corner portion of the excitation electrode formed round in the convex shape is the same as a radius of the connection electrode formed in a round shape in the concave shape. The quartz crystal resonator element according to claim 1 , wherein the connection electrode facing a corner of the excitation electrode on the connection electrode side is formed in an L shape. 3. The quartz crystal resonator element according to claim 1 , wherein a distance between the rounded corner of the excitation electrode and the connection electrode is equal to or longer than a length of the extraction electrode. The quartz crystal resonator element according to claim 1 or 2 ,
A package for fixing the crystal vibrating piece;
Crystal vibration device with