JP2018056666A - Crystal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal device which can suppress foreign matters from adhering to a tip of a crystal element and an excitation electrode, and reduce variation of oscillatory frequencies of the crystal element without inhibiting thickness shear vibration.SOLUTION: The crystal device comprises: a rectangular substrate 110a; an electrode pad 111 provided along one side of the substrate 110a; a rectangular crystal blank 121; an excitation electrode 122 provided on the crystal blank 121; and a pair of rectangular extraction electrodes 123 provided along one side of the crystal blank 121 separately at an interval from the excitation electrode 122, which further comprises: a crystal element 120 mounted on the electrode pad 111 via a conductive adhesive 140; and a lid body 130 provided for air-tightly sealing the crystal element 120. A second center point P2 of the crystal blank 121 is provided to be positioned at the electrode pad 111 side with respect to a first center point P1 of the substrate 110a in a planar view.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a crystal device used in, for example, an electronic apparatus.

  A quartz crystal device uses a quartz crystal effect of a quartz crystal element to cause a thickness-shear vibration so that both surfaces of a quartz base plate are displaced from each other, thereby generating a specific frequency. A crystal device including a crystal element mounted on an electrode pad provided on a substrate via a conductive adhesive has been proposed (for example, see Patent Document 1 below). The crystal element has excitation electrodes on both main surfaces of the crystal base plate, one end of the crystal element is a fixed end connected to the upper surface of the substrate, and the other end is a free end spaced from the upper surface of the substrate. Cantilevered support structure.

JP 2002-111435 A

  In the above-described crystal device, there is a possibility that foreign matter adheres to the tip portion of the crystal element and the excitation electrode, and the thickness-shear vibration is hindered. Further, in the quartz device, there is a possibility that the oscillation frequency of the quartz element may fluctuate due to the inhibition of the thickness shear vibration.

  The present invention has been made in view of the above-described problems, and suppresses foreign matter from adhering to the tip of the crystal element and the excitation electrode, thereby reducing fluctuations in the oscillation frequency of the crystal element without inhibiting thickness-shear vibration. The present invention provides a crystal device that can be used.

  A quartz crystal device according to one aspect of the present invention includes a rectangular substrate, an electrode pad provided along one side of the substrate, a rectangular crystal plate, an excitation electrode provided on the crystal plate, A quartz element mounted on the electrode pad via a conductive adhesive, and having a pair of rectangular extraction electrodes provided along one side of the quartz base plate with a space between the excitation electrodes And a lid provided to hermetically seal the crystal element, and the second center point of the crystal base plate is closer to the electrode pad side than the first center point of the substrate in plan view. It is provided to be located.

  A quartz crystal device according to one aspect of the present invention includes a rectangular substrate, an electrode pad provided along one side of the substrate, a rectangular crystal plate, an excitation electrode provided on the crystal plate, A crystal element mounted on an electrode pad via a conductive adhesive, and having a pair of rectangular lead electrodes provided along one side of the quartz base plate with a space between the excitation electrodes, A lid provided for hermetically sealing the crystal element, and the second center point of the crystal base plate is located on the electrode pad side with respect to the first center point of the substrate in plan view It is provided to do. Since such a quartz crystal device can increase the distance between the tip of the quartz crystal element and the outer peripheral edge of the substrate as compared with the conventional quartz device, the joining member used when joining the lid is scattered. However, adhesion to the tip of the crystal element and the excitation electrode can be suppressed, and the inhibition of thickness-shear vibration can be reduced. In addition, since such a quartz crystal device can reduce the inhibition of the thickness shear vibration of the quartz crystal element, it is possible to stably output the oscillation frequency of the quartz crystal element.

It is a disassembled perspective view which shows the crystal device in this embodiment. It is sectional drawing in AA of the quartz crystal device shown by FIG. (A) It is the top view which looked at the package which comprises the crystal device in this embodiment from the upper surface, (b) The top view which looked at the package which comprises the crystal device in this embodiment from the lower surface. (A) It is a top view which shows the 2nd center point P2 seeing the crystal element which comprises the crystal device in this embodiment from the upper surface, (b) The crystal element which comprises the crystal device in this embodiment is seen from an upper surface. FIG. 6 is a plan view showing the positional relationship of a third center point P3. It is a top view which shows the positional relationship with the 1st center point P1, the 2nd center point P2, and the 3rd center point P3 seeing the quartz crystal device in this embodiment from the upper surface. (A) It is a top view which shows the 2nd center point P2 seeing the crystal | crystallization element which comprises the crystal device in the modification of this embodiment from the upper surface, (b) It comprises the crystal device in the modification of this embodiment. It is a top view which shows the positional relationship of the 3rd center point P3 seeing a quartz crystal element from the upper surface. It is a top view which shows the positional relationship with the 1st center point P1, the 2nd center point P2, and the 3rd center point P3 seeing the quartz crystal device in the modification of this embodiment from the upper surface.

  As shown in FIGS. 1 and 2, the crystal device in the present embodiment includes a package 110 and a crystal element 120 bonded to the package 110. The package 110 has a recess K surrounded by the upper surface of the substrate 110a and the inner surface of the frame 110b. Such a crystal device is used to output a reference signal used in an electronic device or the like.

  The substrate 110a has a rectangular shape and functions as a mounting member for mounting the crystal element 120 mounted on the upper surface. A pair of electrode pads 111 for mounting the crystal element 120 is provided on the upper surface of the substrate 110a.

  In addition, external terminals 112 are provided at the four corners of the lower surface of the substrate 110a. Two of the four external terminals 112 are electrically connected to the crystal element 120. In addition, the pair of external terminals 112 that are electrically connected to the crystal element 120 are provided so as to be positioned diagonally on the lower surface of the substrate 110a.

  The substrate 110a is made of an insulating layer made of a ceramic material such as alumina ceramic or glass-ceramic. The substrate 110a may be one using an insulating layer or may be a laminate of a plurality of insulating layers. A wiring pattern (not shown) for electrically connecting the electrode pads 111 provided on the upper surface of the frame 110b and the external terminals 112 provided on the lower surface of the substrate 110a on the surface and inside of the substrate 110a. And via conductors (not shown).

  The frame 110b is disposed on the upper surface of the substrate 110a, and is for forming the recess K on the upper surface of the substrate 110a. The frame 110b is made of a ceramic material such as alumina ceramics or glass-ceramics, and is formed integrally with the substrate 110a.

  The electrode pad 111 is for mounting the crystal element 120. A pair of electrode pads 111 are provided on the upper surface of the substrate 110a, and are provided adjacent to each other along one side of the inner periphery of the substrate 110a inside the frame 110b.

  The external terminal 112 is used for bonding to a mounting pad (not shown) on an external mounting substrate such as an electric device. The external terminals 112 are provided at the four corners of the lower surface of the substrate 110a. The external terminal 112 includes a first external terminal 112a, a second external terminal 112b, a third external terminal 112c, and a fourth external terminal 112d. The third external terminal 112c is electrically connected to the sealing conductor pattern 117 via the third via conductor 114c. In addition, at least one of the external terminals 112 is connected to a mounting pad connected to a ground potential that is a reference potential on a mounting substrate such as an electronic device. As a result, the lid 130 bonded to the sealing conductor pattern 117 is connected to the third external terminal 112c having the ground potential. Therefore, the shielding performance in the recess K by the lid 130 is improved.

  The wiring pattern 113 is for electrically connecting the electrode pad 111 and the via conductor 114. The wiring pattern 113 includes a first wiring pattern 113a and a second wiring pattern 113b. One end of the first wiring pattern 113a is electrically connected to the first electrode pad 111a, and the other end of the first wiring pattern 113a is electrically connected to the first via conductor 114a. One end of the second wiring pattern 113b is electrically connected to the second electrode pad 111b, and the other end of the second wiring pattern 113b is electrically connected to the second via conductor 114b.

  Further, the wiring pattern 113 is provided so as to overlap the frame 110b in plan view. By doing so, the crystal device suppresses the generation of stray capacitance between the wiring pattern 113 and the crystal element 120, so that this stray capacitance is not added to the crystal element 120, and therefore the oscillation frequency Can be prevented from fluctuating. Further, even when an external force is applied to the crystal device and a bending moment is generated in the long side direction of the frame 110b, the frame 110b is provided in addition to the substrate 110a, so that the frame 110b is provided. Becomes difficult to deform. Therefore, the wiring pattern 113 provided at a position overlapping the frame 110b in plan view is less likely to be disconnected, and the oscillation frequency is not output.

  The first wiring pattern 113a is electrically connected to the first electrode pad 111a and the first via conductor 114a. The first wiring pattern 113a extends in the long side direction of the frame 110b adjacent to the first electrode pad 111a, and a part of the first wiring pattern 113a is exposed. The second wiring pattern 113b is electrically connected to the second electrode pad 111b and the second via conductor 114b. The second wiring pattern 113b extends in the long side direction of the frame 110b adjacent to the second electrode pad 111b, and a part of the second wiring pattern 113b is exposed.

  In this manner, a part of the wiring pattern 113 extends from the electrode pad 111 toward the long side of the frame 110b and is exposed in the recess K, thereby mounting the crystal element 120. In this case, even if the conductive adhesive 140 overflows from the electrode pad 111, the conductive adhesive 140 easily flows along the conductive adhesive 140 and the wiring pattern 113 having good wettability. It is possible to prevent the conductive adhesive 140 from adhering to the excitation electrode 122 without flowing out in the direction.

  Here, as shown in FIG. 3, the first center point P1 is a point corresponding to the center of the substrate 110a when the upper surface of the substrate 110a is viewed in plan. Further, as shown in FIG. 3, a straight line passing through the first center point P1 when the upper surface of the substrate 110a is viewed in plan is a first virtual straight line CL1. Further, a part of the exposed wiring pattern 113 is provided so as to be line symmetric with respect to a first virtual straight line CL1 that passes through the first center point P1 of the substrate 110a and is parallel to the long side of the substrate 110a. . The first wiring pattern 113a exposed in this way and the exposed second wiring pattern 113b pass through the first center point P1 of the substrate 110a and are parallel to the long side of the substrate 110a. Since the conductive adhesive 140 overflows from the electrode pad 111 when the quartz crystal element 120 is mounted, the amount of the conductive adhesive 140 that overflows is reduced by being provided at a line-symmetrical position. It becomes easy to become equal, and it can control that crystal element 120 tilts.

  The via conductor 114 is for electrically connecting the external terminal 112 and the wiring pattern 113 or the sealing conductor pattern 117. Both ends of the via conductor 114 are connected to the external terminal 112 and the wiring pattern 113 or the sealing conductor pattern 117. The via conductor 114 includes a first via conductor 114a, a second via conductor 114b, and a third via conductor 114c. Thus, the external terminal 112 is electrically connected to the wiring pattern 113 or the sealing conductor pattern 117 through the via conductor 114.

  The sealing conductor pattern 117 plays a role of improving the wettability of the bonding member 131 when bonded to the lid 130 via the bonding member 131. The sealing conductor pattern 117 is electrically connected to the third external terminal 112c, which is at least one of the external terminals 112, via the third via conductor 114c. The sealing conductor pattern 117 is formed to have a thickness of, for example, 10 to 25 μm by sequentially applying nickel plating and gold plating on the surface of the conductor pattern made of, for example, tungsten or molybdenum so as to surround the upper surface of the frame 110b in an annular shape. Has been.

  Here, a method for manufacturing the package 110 will be described. When the substrate 110a and the frame 110b constituting the package 110 are made of alumina ceramic, first, a plurality of ceramic green sheets obtained by adding and mixing an appropriate organic solvent or the like to a predetermined ceramic material powder is prepared. In addition, a predetermined conductor paste is applied to the surface of the ceramic green sheet or a through-hole previously punched by punching the ceramic green sheet by screen printing or the like. Further, these green sheets are laminated and press-molded and fired at a high temperature. Finally, it is produced by applying nickel plating, gold plating, silver palladium, or the like to a predetermined portion of the conductor pattern, specifically, a portion to be the electrode pad 111, the external terminal 112, the wiring pattern 113, and the sealing conductor pattern 117. Is done. Moreover, the conductor paste is comprised from the sintered compact etc. of metal powders, such as tungsten, molybdenum, copper, silver, or silver palladium, for example.

(Crystal element)
As shown in FIGS. 1 and 2, the crystal element 120 is mounted on the electrode pad 111 on the substrate 110a via the conductive adhesive 140. The crystal element 120 plays a role of oscillating a reference signal of an electronic device or the like by stable mechanical vibration and a piezoelectric effect. As shown in FIG. 4, the crystal element 120 includes a crystal base plate 121, excitation electrodes 122 provided on the top and bottom surfaces of the crystal base plate 121, and a drawer provided along one side of the crystal base plate 121. And electrode 123. In addition, the crystal element 120 is integrally formed by a photolithography technique and an etching technique. The quartz base plate 121 has a substantially rectangular shape in plan view.

  Here, as shown in FIG. 4A, the second center point P <b> 2 is a point corresponding to the center of the crystal base plate 121 when the upper surface of the crystal element 120 is viewed in plan. A straight line passing through the second center point P2 of the crystal element plate 121 when the upper surface of the crystal element plate 121 is viewed in plan is a second virtual line CL2. As shown in FIG. 4A, the crystal element plate 121 is axisymmetric with respect to the second virtual straight line CL2 when the upper surface of the crystal element plate 121 is viewed in plan. The second center point P2 of the crystal base plate 121 is provided so as to be positioned on one side facing one side of the crystal base plate 121 with respect to the first center point P1 of the substrate 110a in plan view.

  The second center point P2 of the quartz base plate 121 is provided so as to be positioned on the electrode pad 111 side with respect to the first center point P1 of the substrate 110a in plan view. By doing in this way, the distance of the front-end | tip of the crystal | crystallization element 120 and the outer periphery of the board | substrate 110a can be lengthened compared with the conventional crystal device. That is, the distance between the tip of the crystal element 120 and the inner peripheral wall of the frame 110b on the side where the electrode pad 111 is not provided can be increased. Therefore, even if the joining member 130 used when joining the lid 130 is scattered in the recess K, it is prevented from adhering to the tip of the crystal element 120 and the excitation electrode 122, and thickness-shear vibration is inhibited. This can be reduced. In addition, since such a quartz crystal device can reduce the inhibition of the thickness shear vibration of the quartz crystal element 120, the oscillation frequency of the quartz crystal element 120 can be output stably.

  The quartz base plate 121 is made of a piezoelectric material that performs stable mechanical vibration. For example, a quartz crystal member having a crystal axis composed of an X axis, a Y axis, and a Z axis that are orthogonal to each other is used. . At this time, the main surface of the quartz base plate 121 is a surface obtained by rotating a surface parallel to the X axis and the Z axis counterclockwise around the X axis as viewed in the negative direction of the X axis. It is parallel. For example, the main surface of the quartz base plate 121 is a surface parallel to the X axis and the Z axis rotated about 37 ° counterclockwise around the X axis as viewed in the negative direction of the X axis. It is parallel to the surface.

  Here, the Example of each dimension of the quartz base plate 121 is demonstrated. The crystal base plate 121 has a substantially rectangular shape in plan view, the long side dimension is 0.5 mm to 3.2 mm, and the short side dimension is 0.2 mm to 2.5 mm. It has become.

  The excitation electrode 122 and the extraction electrode 123 provided on the crystal base plate 121 are for applying a voltage from the outside of the crystal base plate 121. Although not shown in particular, the excitation electrode 122 and the extraction electrode 123 include, for example, a first metal layer and a second metal layer laminated on the first metal layer. For the first metal layer, a metal having good adhesion to quartz is used, and for example, any one of nickel, chromium, nichrome, or titanium is used. By using a metal having good adhesion to the crystal, even a metal material that is difficult to adhere to the crystal can be used for the second metal layer. The second metal layer is made of a stable metal material having a relatively low electrical resistivity among the metal materials. For the second metal layer, for example, any one of gold, an alloy containing gold, silver, or an alloy containing silver is used. In this way, by using a metal material having a relatively low electrical resistivity among the metal materials, the excitation electrode 122 and the extraction electrode 123 can reduce their own electrical resistivity. As a result, the quartz crystal An increase in the equivalent series resistance value of the element 120 can be reduced. Further, in this way, by using a stable metal material, it is oxidized with surrounding oxygen, and the weight of the excitation electrode 122 and the extraction electrode 123 changes accordingly, and the frequency of the crystal element 120 changes. It can be reduced.

  The excitation electrodes 122 (122a, 122b) are for applying a voltage to the crystal element 120. The excitation electrode 122 is a pair, and one excitation electrode 122 a is provided on the upper surface of the crystal base plate 121, and the other excitation electrode 122 b is provided on the lower surface of the crystal base plate 121. The excitation electrode 122 has a substantially rectangular shape in plan view of the crystal element 120.

  Here, as shown in FIG. 4B, the third center point P3 is a point corresponding to the center of the excitation electrode 122 when the upper surface of the crystal element 120 is viewed in plan. A straight line passing through the third center point P3 of the excitation electrode 122 in plan view of the upper surface of the quartz base plate 121 is a third virtual straight line CL3. The excitation electrode 122 is axisymmetric with respect to the third virtual straight line CL3 passing through the third center point P3 of the excitation electrode 122 in plan view of the crystal element 120. With this configuration, when a voltage is applied to the excitation electrode 122, the charges stored in the excitation electrode 122 are axisymmetric with respect to the third imaginary straight line CL 3, and the crystal sandwiched between the excitation electrodes 122. Vibration energy for causing part of the base plate 121 to undergo thickness-shear vibration can be distributed symmetrically with respect to the third virtual straight line CL3. Therefore, in this embodiment, since vibration energy can be distributed symmetrically with respect to the third virtual line CL3, the left and right vibration balance can be improved with respect to the third virtual line CL3. For this reason, it is possible to reduce an increase in the equivalent series resistance value due to a decrease in the left and right vibration balance with respect to the third virtual straight line CL3.

  The third center point P3 of the excitation electrode 122 is provided so as to be positioned between the first center point P1 of the substrate 110a and the second center point P2 of the quartz base plate 121 in plan view. . In this way, when the crystal element 120 is mounted, the portion where the crystal element 120 is bonded with the conductive adhesive 140 is the both ends of one short side of the crystal base plate 121, so that the conductive bonding is performed. The distance from the portion bonded by the agent 140 to the third center point P3 of the excitation electrode 122 can be further increased, and the influence of the conductive adhesive 140, specifically, the conductive adhesive 140 is bonded. Accordingly, it is possible to further reduce the vibration inhibition of the quartz base plate 121. Therefore, the quartz device can be further reduced from increasing the equivalent series resistance value by bonding with the conductive adhesive 140.

  The third center point P 3 of the excitation electrode 122 is located at a position different from the second center point P 2 of the crystal base plate 121, and is located at a position away from one short side of the crystal base plate 121. By doing in this way, the distance of the front-end | tip of the crystal | crystallization element 120 and the outer periphery of the board | substrate 110a can be lengthened compared with the conventional crystal device. That is, the distance between the tip of the crystal element 120 and the inner peripheral wall of the frame 110b can be increased. Therefore, even if the joining member 130 used when joining the lid 130 is scattered in the recess K, it is prevented from adhering to the tip of the crystal element 120 and the excitation electrode 122, and thickness-shear vibration is inhibited. This can be reduced. In addition, since such a quartz crystal device can reduce the inhibition of the thickness shear vibration of the quartz crystal element 120, the oscillation frequency of the quartz crystal element 120 can be output stably.

  Further, the first center point P1, the second center point P2, and the third center point P3 are provided so as to be positioned on the same straight line in the virtual straight line CL. In this way, when the crystal element 120 is fixed with the conductive adhesive 140 and a voltage is applied to the excitation electrode 122, the charges stored in the excitation electrode 122 are line symmetric with respect to the virtual straight line CL, and the excitation is performed. It is possible to distribute vibration energy for causing a part of the quartz base plate 121 sandwiched between the electrodes 122 for thickness-shear vibration to be symmetrical with respect to the virtual straight line CL. Therefore, in the present embodiment, vibration energy can be distributed symmetrically with respect to the virtual straight line CL, so that the left and right vibration balance can be further improved with respect to the virtual straight line CL. For this reason, it becomes possible to further reduce the increase in the equivalent series resistance value due to the decrease in the left and right vibration balance with respect to the virtual straight line CL.

  Here, a method of forming the excitation electrode 122 and the extraction electrode 123 will be described. Here, a case where the excitation electrode 122 and the extraction electrode 123 are integrally formed using a photolithography technique and an etching technique will be described as an example. First, a quartz wafer is prepared in a state where portions to become the quartz base plate 121 are connected, and a metal film to be the excitation electrode 122 and the extraction electrode 123 is formed on both main surfaces of the quartz wafer. Next, a photosensitive resist is applied on the metal film, and exposed to a predetermined pattern and developed. At this time, after development, the photosensitive resist remains in portions that become the excitation electrode 122 and the extraction electrode 123, specifically, portions that become the excitation electrode 122 and the extraction electrode 123. Finally, the remaining photosensitive resist is removed, whereby the excitation electrode 122 and the extraction electrode 123 are formed on the crystal base plate 121 of the crystal wafer. Note that the excitation electrode 122 and the extraction electrode 123 may be formed separately, or may be formed using a sputtering technique or an evaporation technique instead of a photolithography technique and an etching technique, or a photolithography technique and an etching technique. You may form combining a technique and sputtering technique or a vapor deposition technique.

  The lid 130 is made of, for example, an Fe—Ni alloy (42 alloy), an Fe—Ni—Co alloy (Kovar), or the like. Such a lid 130 hermetically seals the recess K in a nitrogen atmosphere or a vacuum atmosphere. Specifically, the lid 130 is placed on the frame 110b of the package 110 in a nitrogen atmosphere or a vacuum atmosphere, and the surface of the sealing conductor pattern 117 provided on the upper surface of the frame 110b and the lid The seam welding is performed by applying a predetermined current so that the joining member 131 of the body 130 is melted, thereby joining the frame body 110b.

  The conductive adhesive 140 contains conductive powder as a conductive filler in a binder such as silicone resin, and the conductive powder includes aluminum, molybdenum, tungsten, platinum, palladium, silver, titanium, One containing either nickel or nickel iron, or a combination thereof is used. Moreover, as a binder, a silicone resin, an epoxy resin, a polyimide resin, or a bismaleimide resin is used, for example.

  The lid body 130 has a rectangular shape, and is for hermetically sealing the concave portion K in a vacuum state or the concave portion K filled with nitrogen gas or the like. Specifically, the lid 130 is placed on the upper surface of the sealing conductor pattern 117 provided on the frame 110b in a predetermined atmosphere. When heat is applied to the bonding member 131 provided on the lower surface of the lid body 130, the bonding member 131 is melt-bonded to the sealing conductor pattern 117. The lid 130 is made of an alloy containing at least one of iron, nickel, and cobalt, for example.

  The joining member 131 is provided from the upper surface of the sealing conductor pattern 117 of the frame body 110 b to the lower surface of the lid body 130. For example, in the case of glass, the joining member 131 is a glass that melts at 300 ° C. to 400 ° C., and is made of, for example, low-melting glass or lead oxide-based glass containing vanadium. Glass is in the form of a paste to which a binder and a solvent are added. After being melted, the glass is solidified and joined to another member. The joining member 131 is provided by, for example, applying glass frit paste by a screen printing method and drying. In addition, when the joining member 131 is printed on the upper surface of the frame 110b, the joining member 131 is printed on the entire circumference of the frame 110b so that the joining members 131 overlap the four corners of the frame 110b. Therefore, the thickness of the bonding member 131 at the four corners is provided to be thicker than the thickness of other portions where the bonding member 131 is provided. The composition of the lead oxide glass is composed of lead oxide, lead fluoride, titanium dioxide, niobium oxide, bismuth oxide, boron oxide, zinc oxide, ferric oxide, copper oxide and calcium oxide.

  For example, in the case of an insulating resin, the bonding member 131 is made of an epoxy resin or a polyimide resin. The thickness of the joining member 131 provided between the frame body 110b and the lid body 130 is 30 to 100 μm.

  For example, when the joining member 131 is gold tin, the thickness of the layer of the joining member 131 is 10 to 40 μm. For example, the component ratio is 70 to 80% for gold and 20 to 30% for tin. May be used. For example, when the joining member 131 is silver brazing, the thickness of the layer of the joining member 131 is 10 to 40 μm. For example, the component ratio is 70 to 80% for silver and 20 to 30% for copper. May be used.

  The crystal device according to the present embodiment includes a rectangular substrate 110a, an electrode pad 111 provided along one side of the substrate 110a, a rectangular crystal substrate 121, and an excitation electrode provided on the crystal substrate 121. 122 and a pair of rectangular extraction electrodes 123 provided along one side of the quartz base plate 121 with a space between the excitation electrode 122 and the electrode pad 111 via the conductive adhesive 130. The crystal element 120 mounted thereon and a lid 130 provided to hermetically seal the crystal element 120, and the second center point P2 of the crystal base plate 121 has a substrate 110a in plan view. The first center point P1 is located on the electrode pad 111 side. Since such a quartz crystal device can increase the distance between the tip of the quartz crystal element 120 and the outer peripheral edge of the substrate 110a as compared with a conventional quartz device, a joining member used when joining the lid 130. Even if 131 scatters, it can be prevented from adhering to the tip of the quartz crystal element 120 and the excitation electrode 122, and the thickness shear vibration can be prevented from being inhibited. In addition, since such a quartz crystal device can reduce the inhibition of the thickness shear vibration of the quartz crystal element 120, the oscillation frequency of the quartz crystal element 120 can be output stably.

  In the crystal device according to the present embodiment, the third center point P3 of the excitation electrode 122 is located between the first center point P1 of the crystal element 120 and the second center point P2 of the substrate 110a in plan view. It is provided to do. In this way, when the crystal element 120 is mounted, the portion where the crystal element 120 is bonded with the conductive adhesive 140 is the both ends of one short side of the crystal base plate 121, so that the conductive bonding is performed. The distance from the portion bonded by the agent 140 to the third center point P3 of the excitation electrode 122 can be further increased, and the influence of the conductive adhesive 140, specifically, the conductive adhesive 140 is bonded. Accordingly, it is possible to further reduce the vibration inhibition of the quartz base plate 121. Therefore, the quartz device can be further reduced from increasing the equivalent series resistance value by bonding with the conductive adhesive 140.

  Further, the quartz crystal device according to the present embodiment is provided such that the first center point P1, the second center point P2, and the third center point P3 are positioned on the same straight line on the virtual straight line CL. In this way, when the crystal element 120 is fixed with the conductive adhesive 140 and a voltage is applied to the excitation electrode 122, the charges stored in the excitation electrode 122 are line symmetric with respect to the virtual straight line CL, and the excitation is performed. It is possible to distribute vibration energy for causing a part of the quartz base plate 121 sandwiched between the electrodes 122 for thickness-shear vibration to be symmetrical with respect to the virtual straight line CL. Therefore, in the present embodiment, vibration energy can be distributed symmetrically with respect to the virtual straight line CL, so that the left and right vibration balance can be further improved with respect to the virtual straight line CL. For this reason, it becomes possible to further reduce the increase in the equivalent series resistance value due to the decrease in the left and right vibration balance with respect to the virtual straight line CL.

(Modification)
Hereinafter, a crystal device according to a modification of the present embodiment will be described. Note that, in the quartz crystal device according to the modification of the present embodiment, the same parts as those of the quartz crystal device described above are denoted by the same reference numerals, and description thereof will be omitted as appropriate. The quartz crystal device according to the modification of the present embodiment is different from the present embodiment in that convex portions 224 are formed on the upper surface and the lower surface of the quartz base plate 221 as shown in FIGS.

  As shown in FIG. 7, the crystal element 220 is mounted on the electrode pad 111 on the substrate 110 a via the conductive adhesive 140. The crystal element 220 plays a role of oscillating a reference signal of an electronic device or the like by stable mechanical vibration and a crystal effect. As shown in FIG. 6, the crystal element 220 includes a crystal base plate 221, convex portions 224 provided on the top and bottom surfaces of the crystal base plate 221, and excitation electrodes provided on the top and bottom surfaces of the convex portion 224. 222 and a lead electrode 223 provided along one side of the crystal base plate 221. In the crystal element 220, a crystal base plate 221 and a convex portion 224 are integrally formed by a photolithography technique and an etching technique. The crystal base plate 221 has a substantially rectangular shape in plan view.

  By making the convex portion 224 thicker than the thickness of the quartz base plate 221 in the vertical direction, when a portion of the convex portion 224 is caused to undergo thickness-shear vibration by the reverse piezoelectric effect and piezoelectric effect, the vibration state of the thickness-shear vibration is large. It is for making a different state. The convex portion 224 includes a first convex portion 224 a provided on the upper surface of the crystal base plate 221 and a second convex portion 224 b provided on the lower surface of the crystal base plate 221.

  Further, the convex portion 224 has a thickness in the vertical direction of 30 μm to 167 μm. The quartz base plate 221 around the convex portion 224 has a vertical thickness of 27.30 μm to 151.82 μm. The convex portion 224 has a substantially rectangular shape in plan view, the dimension parallel to the long side of the crystal base plate 221 is 0.3 mm to 2.7 mm, and the short side of the crystal base plate 221 The dimension parallel to is 0.2 mm to 2.4 mm.

  Here, a method of forming such a crystal base plate 221 will be described. Such a method of forming the crystal blank 121 includes, for example, a crystal wafer preparation process, a first etching process, and a second etching process. In the crystal wafer preparation step, first, a crystal wafer having crystal axes composed of an X axis, a Y axis, and a Z axis orthogonal to each other is prepared. At this time, the thickness of the quartz wafer in the vertical direction is the thickness of the convex portion 224 in the vertical direction. In addition, the main surface of the crystal wafer has the same cut angle as the main surface of the convex portion 224. Therefore, the main surface of the quartz wafer is a surface obtained by rotating a plane parallel to the X-axis and the Z-axis by a predetermined angle counterclockwise around the X-axis and viewing the negative direction of the X-axis. It is parallel to. In the first etching process, a photolithography technique and an etching technique are used. First, protective metal films are provided on both main surfaces of a quartz wafer, a photosensitive resist is applied on the protective metal film, and exposure and development are performed in a predetermined pattern. At this time, when the crystal wafer is viewed in plan, the photosensitive resist and the protective metal film remain only in a portion that becomes the convex portion 224. Thereafter, the crystal wafer is immersed in a predetermined etching solution, and the crystal wafer is etched until the vertical thickness of the etched crystal wafer is the same as the vertical thickness of the crystal base plate 221 around the convex portion 224. Finally, the photosensitive resist and the protective metal film remaining on the quartz wafer are peeled off. In the second etching step, protective metal films are provided on both main surfaces of the crystal wafer after the first etching step, a photosensitive resist is applied on the protective metal film, and exposure and development are performed in a predetermined pattern. At this time, when the quartz wafer is viewed in plan, the photosensitive resist and the protective metal film remain in the portion that becomes the quartz base plate 221. Thereafter, the quartz wafer is etched by dipping in a predetermined etching solution. As described above, a plurality of crystal base plates 221 are formed in a crystal wafer in a state where a part of them is connected.

  Here, as shown in FIG. 6B, the fourth center point P4 is a point corresponding to the center of the convex portion 224 when the upper surface of the crystal element 220 is viewed in plan. A straight line passing through the fourth center point P4 of the convex portion 224 when the upper surface of the crystal base plate 222 is viewed in plan is a fourth virtual straight line CL4. The convex portion 224 is axisymmetric with respect to a fourth virtual straight line CL4 passing through the fourth center point P4 of the crystal base plate 221 in plan view. Further, the fourth center point P4 of the convex portion 224 is located on the fourth virtual straight line CL4 in plan view of the crystal base plate 221. At this time, the fourth center point P4 of the convex portion 224 does not overlap with the second center point P2 of the crystal base plate 221, and the second center point P2 of the crystal base plate 221 is the fourth center point P4 of the convex portion 224. Compared to the crystal plate 221, it is located on one short side. That is, when the upper surface of the crystal element plate 221 is viewed in plan, the distance from the fourth center point P4 of the convex part 224 to one short side of the crystal element plate 221 is the crystal distance from the second center point P2 of the crystal element plate 221. It is longer than the distance to one short side of the base plate 221. With such a configuration, as shown in FIG. 7, when the crystal element 220 is used as a crystal device, a position where the crystal element 220 is bonded with the conductive adhesive 140 is one short side of the crystal base plate 221. , The distance from the portion bonded by the conductive adhesive 140 to the fourth center point P4 of the convex portion 224 can be increased, and the influence of the conductive adhesive 140, specifically Further, it is possible to further reduce the vibration inhibition of the convex portion 224 due to the conductive adhesive 140 being adhered. Therefore, the quartz device can be reduced by increasing the equivalent series resistance value by bonding with the conductive adhesive 140.

  A pair of excitation electrodes 222 (222a, 222b) is provided on both main surfaces of the convex portion 224. When a voltage is applied to the pair of excitation electrodes 222, the convex portion 224 causes a portion of the convex portion 224 sandwiched between the excitation electrodes 222 to vibrate at a predetermined frequency due to the reverse piezoelectric effect and the piezoelectric effect. To do. In general, the frequency of thickness shear vibration is determined by the thickness of the convex portion 224 in the vertical direction since the ease of thickness shear vibration differs depending on the thickness of the convex portion 224 in the vertical direction. Therefore, when the thickness shear vibration is performed in a low frequency band such as 30 MHz or less, vibration energy is required to cause the thickness shear vibration compared to the case of thickness shear vibration in a frequency band higher than 30 MHz. For this reason, as compared with a case where thickness-shear vibration is performed in a high frequency band, vibration leakage occurs even in a vibration part that is not sandwiched between the excitation electrodes 222.

  The quartz base plate 221 around the convex portion 224 has a thickness slip due to mounting when the crystal element 220 is mounted on the substrate 110a while concentrating vibration energy on the convex portion 224 when a voltage is applied to the excitation electrode 222. This is to reduce the influence on vibration. The quartz base plate 221 around the convex portion 224 is provided along the convex portion 224, and the thickness in the vertical direction is thinner than the thickness in the vertical direction of the convex portion 224. The crystal element plate 221 around the convex portion 224 is composed of an inclined portion provided along the outer edge of the convex portion 224 and a flat plate portion provided along the outer edge of the inclined portion.

  The inclined portion is provided along the outer edge of the convex portion 224. Further, the thickness of the inclined portion is gradually reduced from the convex portion 224 to the quartz base plate 221 around the convex portion 224. The inclined portion is formed between the crystal base plate 221 around the convex portion 224 around the convex portion 224 by utilizing the fact that the etching is easy depending on the positional relationship of the crystal axes. As described above, when the crystal element 220 is mounted on the substrate 110a using the conductive adhesive 140 by providing the gap between the convex portion 224 and the crystal base plate 221 around the convex portion 224, the convex portion The influence on the convex part 224 by adhering the quartz base plate 221 around the 224 with the conductive adhesive 140 can be reduced. Here, since the ease of etching differs depending on the positional relationship with each crystal axis, when the crystal element 220 is viewed in plan, all the widths of the inclined portions are not the same, and are different depending on the location.

  In this way, by using the crystal base plate 221 including the convex portion 224 and the crystal base plate 221 which is around the convex portion 224 and whose thickness in the vertical direction is smaller than that of the convex portion 224, a part of the convex portion 224 is reversed. When the thickness-shear vibration is caused by the piezoelectric effect and the piezoelectric effect, the vibration state of the thickness-shear vibration can be greatly different between the convex portion 224 and the quartz base plate 221 around the convex portion 224. Therefore, by adopting such a configuration, it becomes possible to concentrate the vibration energy only on the convex portion 224 as compared with the case where a flat crystal element plate is used. As a result, in the crystal element 120 using such a crystal element plate 221, it is possible to reduce the increase in the equivalent series resistance value due to the dispersion or leakage of vibration energy.

  Further, as shown in FIG. 6, the excitation electrode 222 is provided so as to be positioned on the inner edge side of the convex portion 224 when the crystal element 220 is viewed in plan. A part of the convex portion 224 sandwiched in the vertical direction of the convex portion 224 of the excitation electrode 222 vibrates due to the piezoelectric effect and the inverse piezoelectric effect. With this configuration, when a portion of the convex portion 224 sandwiched between the excitation electrodes 222 vibrates, vibration leakage occurs from the outer edge of the first excitation electrode 222a toward the outer edge of the vibration portion 222. Even if this leaked vibration is reflected by the inclined surface of the inclined portion provided on the outer edge of the convex 224, the excitation electrode 222a is positioned on the inner edge side of the vibrating portion 222 in plan view. Therefore, it is possible to reduce the influence of the inclined portion provided at the edge portion of the convex portion 224. As a result, it is possible to reduce the influence of the inclined portion provided at the edge of the convex portion 224, specifically, the increase in the equivalent series resistance value due to the vibration inhibition by the inclined portion.

  Further, when the crystal element 220 is viewed in plan, the length between two sides positioned so as to sandwich the convex portion 224, specifically, the side of the convex portion 224 parallel to the short side of the crystal base plate 221, The length of the excitation electrode 222a parallel to the short side of the quartz base plate 221 is preferably 5 μm or more and 55 μm or less. When a voltage is applied to the excitation electrode 222, vibration leakage occurs from the portion sandwiched by the excitation electrode 222 in the vertical direction of the convex portion 224 to the portion not sandwiched, and the leaked vibration is the outer edge of the convex portion 224. May be reflected by the inclined portion provided along the line and hinder the vibration of the portion sandwiched between the excitation electrodes 222, and the equivalent series resistance value may increase.

  As shown in FIG. 7, the fourth center point P4 that is the center of the convex portion 224 is located between the first center point P1 of the substrate 110a and the second center point P2 of the crystal element 220 in plan view. It is provided as follows. The fourth center point P4 of the convex portion 224 is at a position different from the second center point P2 of the crystal base plate 221 and is positioned at a position away from one short side of the crystal base plate 221. With such a configuration, as shown in FIG. 7, when both ends of one short side of the crystal base plate 221 are bonded with the conductive adhesive 140 and the crystal element 220 is used as a crystal device, excitation is performed. A part of the convex portion 224 sandwiched between the electrodes 222 can be positioned away from one short side of the crystal base plate 221. Since a part of the convex portion 224 sandwiched between the excitation electrodes 222 is most vibrated when a voltage is applied to the excitation electrode 222, the convex portions 224 sandwiched between the excitation electrodes 122. Can be further away than the portion to be bonded with the conductive adhesive 140. As a result, the influence of the conductive adhesive 140, specifically, the vibration inhibition due to the adhesion of the conductive adhesive 140 can be reduced, and the equivalent series resistance value due to the adhesion with the conductive adhesive 140 is increased. This can be reduced.

  As shown in FIG. 7, the first center point P1, the second center point P2, and the fourth center point P4 are provided so as to be positioned on the same straight line. In this way, when the crystal element 120 is fixed with the conductive adhesive 140 and a voltage is applied to the excitation electrode 122, the charges stored in the excitation electrode 122 are line symmetric with respect to the virtual straight line CL, and the excitation is performed. It is possible to distribute vibration energy for causing a part of the quartz base plate 121 sandwiched between the electrodes 122 for thickness-shear vibration to be symmetrical with respect to the virtual straight line CL. Therefore, in the present embodiment, vibration energy can be distributed symmetrically with respect to the virtual straight line CL, so that the left and right vibration balance can be further improved with respect to the virtual straight line CL. For this reason, it becomes possible to further reduce the increase in the equivalent series resistance value due to the decrease in the left and right vibration balance with respect to the virtual straight line CL.

  In the crystal device according to the present embodiment, the upper surface and the lower surface of the crystal base plate 221 are provided with a rectangular convex portion 224 in plan view, and the fourth center point P4 of the convex portion 224 is viewed in plan view. The first center point P1 of the substrate 110a and the second center point P2 of the crystal element 220 are provided. By doing so, the portions where the crystal element 220 is bonded with the conductive adhesive 140 are both ends of one short side of the crystal base plate 221, thereby protruding from the portion bonded by the conductive adhesive 140. The distance to the 4th center point P4 of the part 224 can be lengthened, and the influence by the conductive adhesive 140, specifically, the vibration inhibition of the convex part 224 by the conductive adhesive 140 adhering is further reduced. It becomes possible to make it. Therefore, the quartz device can be reduced by increasing the equivalent series resistance value by bonding with the conductive adhesive 140.

  The quartz crystal device according to the present embodiment is provided such that the first center point P1, the second center point P2, and the fourth center point P4 are positioned on the same straight line. When the crystal element 220 is fixed with the conductive adhesive 140 and a voltage is applied to the excitation electrode 222, the charge stored in the excitation electrode 222 is axisymmetric with respect to the virtual straight line CL and is sandwiched between the excitation electrodes 222. The vibration energy for causing a part of the quartz base plate 221 to vibrate in thickness sliding can be distributed symmetrically with respect to the virtual straight line CL. Therefore, in the present embodiment, vibration energy can be distributed symmetrically with respect to the virtual straight line CL, so that the left and right vibration balance can be further improved with respect to the virtual straight line CL. For this reason, it becomes possible to further reduce the increase in the equivalent series resistance value due to the decrease in the left and right vibration balance with respect to the virtual straight line CL.

 In addition, it is not limited to this embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. In the above embodiment, the case where the frame 110b is integrally formed of a ceramic material in the same manner as the substrate 110a has been described. However, the frame 110b may be made of metal. In this case, the frame is joined to the conductor film of the substrate via a brazing material such as silver-copper. In the present embodiment, the case where the sealing conductor pattern 117 is formed on the upper surface of the frame 110b has been described. However, when the bonding member 131 is made of glass or insulating resin, the sealing conductor pattern is used. You may join to the frame 110b, without providing 117. FIG.

  In the above embodiment, the case where the frame 110b is provided on the upper surface of the substrate 110a has been described. However, after the crystal element is mounted on the substrate, the lid having the sealing frame provided on the lower surface of the sealing base is provided. The quartz element may be hermetically sealed. The lid is composed of a rectangular sealing base and a sealing frame portion provided along the outer peripheral edge of the lower surface of the sealing base. The lower surface of the sealing base and the inner side of the sealing frame portion An accommodation space is formed with the side surface. The sealing frame portion is for forming an accommodation space on the lower surface of the sealing base. The sealing frame part is provided along the outer edge of the lower surface of the sealing base.

DESCRIPTION OF SYMBOLS 110 ... Package 110a ... Board | substrate 110b ... Frame body 111 ... Electrode pad 112 ... External terminal 113 ... Wiring pattern 114 ... Via conductor 117 ... Conductive pattern 120 for sealing , 220: Quartz element 121, 221 ... Crystal base plate 122, 222 ... Excitation electrode 123, 223 ... Lead electrode 224 ... Convex part 130 ... Lid 131 ... Bonding Member 140 ... conductive adhesive K ... concave P1 ... first center point P2 ... second center point P3 ... third center point P4 ... fourth center point CL ... Virtual line CL1 ... 1st virtual line CL2 ... 2nd virtual line CL3 ... 3rd virtual line CL4 ... 4th virtual line

Claims (5)

A rectangular substrate;
An electrode pad provided along one side of the substrate;
A rectangular crystal base plate, an excitation electrode provided on the crystal base plate, and a pair of lead electrodes having a rectangular shape provided along one side of the crystal base plate with a space between the excitation electrode And a quartz crystal element mounted on the electrode pad via a conductive adhesive, and
A lid provided to hermetically seal the crystal element,
The quartz crystal device, wherein the second center point of the quartz base plate is provided so as to be positioned on the electrode pad side with respect to the first center point of the substrate in plan view. The crystal device according to claim 1,
The third center point of the excitation electrode is provided so as to be positioned between the first center point of the substrate and the second center point of the crystal element in plan view. device. The crystal device according to claim 1,
The upper surface and the lower surface of the quartz base plate are provided with rectangular convex portions in plan view,
The fourth center point of the convex portion is provided so as to be positioned between the first center point of the substrate and the second center point of the crystal element in plan view. . The crystal device according to claim 2,
The quartz crystal device, wherein the first center point, the second center point, and the third center point are provided so as to be located in the same straight line. The crystal device according to claim 3,
The quartz crystal device is characterized in that the first center point, the second center point, and the fourth center point are arranged in the same straight line.

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