JP6573462B2 - Crystal oscillator - Google Patents

Description

  The present invention relates to a quartz crystal resonator including a vibrating body on which a quartz vibrating piece is formed and a pair of sealing bodies that seal the vibrating body.

  A conventional general crystal resonator includes a crystal resonator element having a predetermined shape and vibration mode, a ceramic case for housing the crystal resonator element, and a metal lid for sealing the crystal resonator element. Is formed. The quartz crystal resonator element is electrically connected and supported by an electrode portion having a base end portion provided in the case via a conductive bonding agent.

  On the other hand, by a wafer level package integrally formed by a vibrating body formed by etching or the like from the quartz crystal wafer and a pair of sealing bodies that enclose the quartz vibrating piece by sandwiching the vibrating body Manufactured crystal units are also known.

  Patent Documents 1 and 2 disclose a crystal resonator formed by the wafer level package. The crystal unit using the wafer level package includes a vibrating body composed of a crystal vibrating piece of various vibration modes and a support frame supported at one end so as to surround the crystal vibrating piece, and a pair of enclosing the crystal vibrating piece. The sealing body is formed by punching from a quartz wafer by etching or the like, and the vibrating body is sandwiched between a pair of sealing bodies and sealed.

JP 2013-55632 A JP 2014-150324 A

  Since the crystal resonator formed by the wafer level package can manufacture a large amount of crystal resonators from a single crystal wafer, the number of manufacturing steps and the manufacturing cost can be reduced, and the crystal resonator itself can be made smaller and thinner. It has the advantage of being realized.

  However, since the vibrating body and the sealing body are formed of a thin quartz wafer, there is a problem that the strength against external pressure and impact is not sufficient. As a structure for improving such a problem, Patent Document 2 discloses a crystal resonator in which a reinforcing column is provided on the sealing body side. According to this structure, although the strength of the sealing body itself is increased, the reinforcing effect is not achieved with respect to the support structure of the crystal vibrating piece in the vibrating body.

  On the other hand, when the crystal vibrating piece is a tuning fork type vibration mode, it is known that the smaller the width of the connecting piece for connecting one end of the crystal vibrating piece to the support frame, the less the vibration leakage. Since it is processed by etching, it cannot be formed in a uniform width. For this reason, a part with insufficient support strength occurs in a part of the connecting piece, which causes a decrease in yield and durability during manufacturing.

  Accordingly, an object of the present invention is to provide a crystal resonator capable of reducing vibration leakage and obtaining a stable vibration mode by reinforcing the support of the crystal resonator piece in the vibration member with a pair of sealing bodies. There is.

  In order to solve the above problems, a crystal resonator according to the present invention has a flat plate shape including a crystal vibrating piece and a connecting piece that supports at least one end of the crystal vibrating piece, and a support frame that surrounds the outer periphery of the crystal vibrating piece. And a pair of sealing bodies that have sealing frames in close contact with the upper and lower surfaces of the support frame, respectively, and seal the vibrating body. A pair of reinforcing pieces for supporting the connecting piece is provided so as to face at least a part of the connecting piece when the vibrating body is sandwiched.

  Further, the crystal resonator of the present invention has a connecting piece that supports at least one end of the base of the crystal vibrating piece having a base and a pair of vibrating arms extending from the base, and supports the outer periphery of the crystal vibrating piece. In the quartz resonator including a flat plate-like vibrating body made of a frame and a pair of sealing bodies each having a sealing frame in close contact with the upper and lower surfaces of the support frame and sandwiching the vibrating body, The sealing body is provided with a pair of reinforcing pieces that support the connecting piece so as to face at least a part of the connecting piece when the vibrating body is sandwiched.

  According to the crystal resonator of the present invention, even if the connecting piece that supports one end of the crystal vibrating piece on the support frame is formed narrow, the reinforcing piece provided on the pair of sealing bodies Since it is supported at a position facing the connecting piece, the support strength of the quartz crystal vibrating piece with respect to the support frame is increased, and stable vibration can be obtained.

  Similarly, even if the quartz crystal vibrating piece has a pair of vibrating arm portions extending from the base, a reinforcing piece in which a connecting piece that supports one end of the base is provided on the pair of sealing bodies. Therefore, the vibration in the pair of vibrating arms can be stabilized.

1 is an exploded perspective view of a crystal resonator according to a first embodiment. It is a development top view of the above-mentioned crystal oscillator. FIG. 4 is an exploded sectional view (a) and a completed sectional view (b) of the crystal unit. It is an expanded sectional view of the above-mentioned crystal oscillator. It is a development top view of the crystal oscillator of a 2nd embodiment. It is sectional drawing of the said crystal oscillator. It is an expansion | deployment top view of the crystal oscillator of 3rd Embodiment. It is an expansion | deployment top view of the crystal oscillator of 4th Embodiment. It is a top view of a vibrating body in various support structures of a tuning fork type crystal vibrating piece. It is a top view of the vibrating body of a 5th embodiment.

  Hereinafter, embodiments of the crystal resonator of the present invention will be described in detail with reference to the accompanying drawings. A crystal resonator 11 according to the first embodiment shown in FIG. 1 includes a vibrating body 12 and a pair of sealing bodies 13 and 14 that seal the upper and lower surfaces of the vibrating body 12. The sealing bodies 13 and 14 are formed by etching and dicing a quartz wafer.

  The quartz wafer is shaped like a plate with a cut angle obtained by rotating the X axis about 1 ° from the Z axis plane in an orthogonal coordinate system of the rough crystal with the X axis as the electrical axis, the Y axis as the mechanical axis, and the Z axis as the optical axis It is formed by thinly slicing. Then, a mask pattern is formed on the quartz wafer by a photolithography process, and quartz etching is performed, so that a base 18 and a pair of vibrating arms 19 extending in parallel from the base 18 are formed as shown in FIG. A tuning fork type crystal vibrating piece 15, a rectangular support frame 16 surrounding the outer periphery of the crystal vibrating piece 15, and a connecting piece 17 that connects one end of the support frame 16 and one end of the base 18. A body 12 is formed. Similarly, the pair of sealing bodies 13 and 14 is etched to form a rectangular sealing frame 21, a reinforcing piece 22 protruding from one end of the sealing frame 21 in a planar direction, the sealing frame 21, A recessed portion 23 is formed to be recessed leaving the reinforcing piece 22. The shapes of the vibrating body 12 and the pair of sealing bodies 13 and 14 can also be formed by cutting or punching using a laser or powder beam suitable for fine processing.

  The vibrating arm portion 19 of the quartz crystal vibrating piece 15 extends in parallel from one end of the base portion 18 with a predetermined interval, and excitation electrodes (not shown) having different polarities are formed on the front and back surfaces and side surfaces. The vibrating arm portion 19 is formed to have a thickness of 50 to 200 μm, and the length and width are set according to the vibration frequency. The excitation electrode is formed by uniformly depositing a metal film on the upper and lower surfaces of the crystal vibrating piece 15 by heat evaporation or sputtering, and exposing the photoresist film through a photomask having a photoresist film applied thereon. It is formed by developing to form an electrode pattern and etching the metal film.

  As shown in FIG. 3, the crystal vibrating piece 15 is obtained by tightly fixing the sealing frame 21 of the pair of sealing bodies 13 and 14 to the upper and lower surfaces of the support frame 16 of the vibrating body 12 in a reduced pressure environment. Is hermetically sealed in the recess 23. When the pair of sealing bodies 13, 14 are brought into close contact with the vibrating body 12, the reinforcing piece 22 provided inside each sealing body 13, 14 is connected to the connecting piece 17 provided on the vibrating body 12. It will contact | abut in the state facing the upper surface and the lower surface. Thereby, the base 18 to which the pair of vibrating arms 19 are connected can be supported in a stable state.

  The connecting piece 17 that supports the crystal vibrating piece 15 on the support frame 16 has a greater effect of preventing vibration leakage as the width is narrower. However, since the vibrating body 12 itself is formed of a thin crystal wafer, the vibrating body There is a limit in strength to narrow the width of the connecting piece 17 formed in 12. In the present embodiment, when the pair of sealing bodies 13 and 14 are sealed, the connecting piece 17 is increased in strength in the thickness direction by the pair of reinforcing pieces 22, and accordingly, the width can be reduced. Become. Further, since a pair of excitation electrode patterns (not shown) extending to the quartz crystal vibrating piece 15 are formed on the upper and lower surfaces of the connecting piece 17, an electrical connection surface due to the close contact of the reinforcing piece 22 is increased, and an electric field is increased. The effect which prevents the fall of efficiency is also acquired.

  As described above, the pair of reinforcing pieces 22 can stably support the crystal vibrating piece 15 by contacting the upper and lower surfaces of the connecting piece 17 or any one of the surfaces, but FIG. As shown in FIG. 5), the pair of reinforcing pieces 22 and the upper and lower surfaces of the connecting piece 17 or any one of the faces are opposed to each other with a slight gap 31 of about 0.1 μm to several μm. You may let them. The gap 31 corresponds to the thickness of the bonding layer 20 for bonding the support frame 16 of the vibrating body 12 and the sealing frame 21 of the pair of sealing bodies 13 and 14. The bonding layer 20 is formed of a metal film used for electrical connection between an excitation electrode (not shown) formed on the quartz crystal vibrating piece 15 and an external electrode (not shown). Even when such a slight gap 31 is provided close to each other, the movement of the connecting piece 17 can be restricted, so that the same support effect as that in the case of contact can be obtained.

  Further, as shown in FIG. 4B, the bonding layer 20 can be provided in the gap 31 and the reinforcing piece 22 can be bonded to the connecting piece 17. The bonding layer 20 may be provided in one gap 31 and the other gap 31 may be left as it is. As described above, since the reinforcing piece 22 and the connecting piece 17 are joined and integrated, the support strength can be further increased, so that the crystal vibrating piece 15 in the vibrating body 12 can be stabilized against an external impact. Can be supported.

  5 and 6 show examples of forming reinforcing pieces in the crystal resonator according to the second embodiment. In this embodiment, a pair of reinforcing pieces 24 is provided so as to be limited to the connection portion between the base 18 and the connecting piece 17. The reinforcing piece 24 is formed so as to protrude from the recess 23 of the pair of sealing bodies 13 and 14 toward the sealing frame 21. As a result, it is possible to reinforce the connecting portion between the base portion 18 and the connecting piece 17 that is most susceptible to vibrations caused by the pair of vibrating arm portions 19. As shown in FIG. 4, the pair of reinforcing pieces 24 may be positioned so as to be in contact with or close to the connecting piece 17, and may be fixed via a bonding layer.

  In the above-described embodiment, the tuning fork type crystal vibrating piece is shown as an example. However, even if it is a quartz vibrating piece other than the tuning fork type, such as a thickness shear vibration mode and a contour vibration mode, a connecting piece corresponding to each crystal vibrating piece. By providing the reinforcing piece on the sealing body side so as to correspond to the above, the same effect as described above can be obtained. FIG. 7 shows a configuration example of the vibrating body 42 and the pair of sealing bodies 43 and 44 of the crystal unit 41 of the third embodiment formed by the crystal vibrating piece 45 in the contour vibration mode. The quartz crystal vibrating piece 45 in the vibrating body 42 has vibration nodes at four corners, and is supported by connecting pieces 47 extending from the respective nodes toward the inner corner of the support frame 46. On the other hand, the pair of sealing bodies 43, 44 that sandwich the vibrating body 42 are provided with reinforcing pieces 49 corresponding to the direction in which the connecting pieces 47 extend from the inner corners of the sealing frame 48. For this reason, the vibrating body 42 is in close contact with the pair of sealing bodies 43 and 44 so that the connecting pieces 47 and the corresponding reinforcing pieces 49 are in contact with or close to each other in the thickness direction. The quartz crystal vibrating piece 45 that overlaps and vibrates can be supported in a stable state.

  Further, in addition to the problem of the support strength of the quartz crystal vibrating pieces 15 and 45 described above, the quartz crystal resonator formed with the conventional wafer level package has a mechanical strength of a ceramic material or a metal material in terms of pressure deformation or dropping. There was a problem that it was weaker than a quartz crystal held by a case or the like. FIG. 8 shows a crystal resonator 51 according to a fourth embodiment having a structure for reinforcing this mechanical strength. Similar to the crystal vibrating piece 15 of the first embodiment, the crystal resonator 51 includes a crystal vibrating piece 15 including a pair of vibrating arm portions 19 extending in parallel from the base 18 and a support frame 16 that supports the crystal vibrating piece 15. And a pair of sealing bodies 26, 27 that have sealing frames 21 that are in close contact with the upper and lower surfaces of the support frame 16 and seal the quartz crystal vibrating piece 15, respectively. Yes. In this configuration, one end of the base portion 18 is supported via a first connecting piece 28 extending from the support frame 21, and the other end extends from the support frame 16 between the pair of vibrating arm portions 19. It is supported via two connecting pieces 29. Then, when the quartz crystal vibrating piece 15 is sandwiched between the pair of sealing bodies 26 and 27, the first and second connecting pieces 28 and 29 are brought into contact with or close to each other so as to sandwich the upper and lower surfaces. A pair of opposing reinforcing pieces 30 are provided.

  According to the crystal resonator 51 having the above structure, the reinforcing piece 30 extending in the longitudinal direction along the center of the pair of sealing bodies 26 and 27, and the first connecting piece 28 and the second connecting piece 29 are provided. It is possible to support two places facing the base portion 18 of the quartz crystal vibrating piece 15 in a state where they overlap and have a thickness. Thereby, a stable vibration mode without vibration leakage can be obtained. A space in which the crystal vibrating piece 15 vibrates is formed by the first connecting piece 28 and the second connecting piece 29 of the vibrating body 25 and the reinforcing piece 30 provided in the pair of sealing bodies 26 and 27. Since they are held, even if they are dropped or subjected to an impact from the outside, it is possible to prevent a vibration failure without contacting the crystal vibrating piece 15.

  Next, an optimal arrangement example of the connecting pieces 17 based on the vibrating body 12a similar to that of the first embodiment shown in FIG. 2B will be described. The vibrating body 12a is formed by wet etching from a quartz wafer. When the base 18 and the pair of vibrating arms 19 are punched along the mask pattern by this etching, as shown in FIG. In addition, an anisotropic crystal plane E is likely to be generated inside the connection portion between the base portion 18 and the vibrating arm portion 19 and around the connecting piece 17. Such an anisotropic crystal plane E is irregularly generated depending on the concentration and speed of the etching solution, and thus there may be a shape imbalance between the pair of vibrating arm portions 19.

  Therefore, in the present embodiment, as shown in FIGS. 9B and 9C, a crystal plane E accompanying etching is assumed, and the degree of the crystal plane E is unbalanced with respect to the pair of vibrating arm portions 19. In order to avoid this, a connecting piece 17 that connects the base 18 and the support frame 16 is provided in a direction (X-axis direction) orthogonal to the vibrating arm 19. In FIG. 9B, the base 18 is cantilevered by one connecting piece 17a on one extending from one end of the support frame 16. FIG. In such a cantilever support, since the support strength is required, the width of the connecting piece 17a is set wide. In FIG. 9C, in addition to the connecting piece 17 of FIG. 9A, the base portion 18 is supported in three directions by providing a pair of connecting pieces 17b extending outward from both ends of the base portion 18 in the X-axis direction. Is. As a result, a plurality of anisotropic crystal planes E may be generated, but the shape of the crystal plane at the connecting portion between the base 18 and the pair of vibrating arm portions 19 becomes substantially uniform, and vibrations of the left and right vibrating arm portions are Frequency shift due to imbalance can be prevented.

  FIG. 10 shows the crystal resonator of the fifth embodiment, and shows the planar shape of the vibrating bodies 61 and 71 having the support frames 62 and 72 having different shapes. The vibrating bodies 61, 71 have outer peripheral parts 63, 73 whose support frames 62, 72 are rectangular, and inner peripheral parts 64, 74 surrounding the crystal vibrating piece 15, respectively. By forming a curved surface, the spaces 65 and 75 that enclose the quartz crystal vibrating piece 15 are regulated. FIG. 10A shows a gourd shape in which the space 65 on the upper end side and the lower end side of the quartz crystal vibrating piece 15 is provided with a marginal space 65 on the center side of the quartz crystal vibrating piece 15. b) is formed in an oval shape having a sufficient space with respect to the center portion of the quartz crystal vibrating piece 15 and narrowing the gap toward the upper end side and the lower end side of the quartz crystal vibrating piece 15. A similar corresponding curved surface shape is also formed on the sealing frame of the pair of sealing bodies that sandwich the vibrating bodies 61 and 71.

  In the embodiment shown in FIGS. 10A and 10B, the spaces 65 and 75 surrounding the quartz crystal vibrating piece 15 are formed by the inner peripheral portions 64 and 74 of the support frames 62 and 72 in the vibration of the first embodiment. It can be made narrower than the body 12. In particular, since the areas of the four corners of the support frames 62 and 72 can be secured widely, it is possible to effectively prevent deformation and destruction due to external impact received by the crystal resonator, and a stable vibration mode can be obtained. Can be maintained. Further, since the contact surface between the pair of sealing frames that overlap with the support frame is widened, the bonding strength is increased and the hermetic sealing can be more reliably performed.

  FIG. 10 shows a tuning fork type crystal vibrating piece as an example. However, in addition to the tuning fork type, a quartz vibrating piece such as a thickness-shear vibration mode or a contour vibration mode can be used according to the accommodation space of the quartz vibrating piece. By forming the support frame and the pair of sealing frames, the strength of the entire crystal unit can be reinforced.

  Moreover, a reinforcement process can also be performed to a pair of sealing body itself in each said embodiment. For example, in the case of the quartz crystal resonator 11 according to the first embodiment shown in FIG. 1, a further reinforcing effect can be obtained by forming a metal plating layer or a resin coating layer on the bottom surface of the recess 23 of each of the sealing bodies 13 and 14. Can be obtained.

  As described above, according to the crystal resonators of the above-described embodiments, in the three-layer structure of the vibration body formed from the crystal wafer and the pair of sealing bodies, it faces the connecting piece of the crystal vibration piece of the vibration body. By providing the reinforcing piece that can be supported by the pair of sealing bodies, the quartz vibrating piece can be supported more reliably. In addition, by setting the shape of the support frame of the vibrating body and the shape of the sealing frame of the pair of sealing bodies, it is possible to increase resistance to external pressure and impact. Furthermore, by providing the connecting piece of the crystal vibrating piece in a direction orthogonal to the pair of vibrating arms, the processing shape at the time of etching can be made uniform, and a stable vibration mode by the crystal vibrating piece can be obtained. Is possible.

E Crystal plane 11 Crystal resonator 12 Vibrating body 13, 14 Sealing body 15 Crystal vibrating piece 16 Support frame 17 Connecting piece 18 Base 19 Vibrating arm portion 20 Bonding layer 21 Sealing frame 22 Reinforcing piece 23 Recessed portion 24 Reinforcing piece 25 Vibrating body 26, 27 Sealing body 28 First connecting piece 29 Second connecting piece 30 Reinforcing piece 31 Gap 41 Quartz vibrator 42 Vibrating body 43, 44 Sealing body 45 Crystal vibrating piece 46 Support frame 47 Connecting piece 48 Sealing frame 49 Reinforcing piece 51 Crystal resonator 61, 71 Vibrating body 62, 72 Support frame 63, 73 Outer peripheral part 64, 74 Inner peripheral part 65, 75 Space

Claims (12)

A plate-like vibrating body having a quartz vibrating piece and a connecting piece that supports at least one end of the quartz vibrating piece, and comprising a support frame surrounding the outer periphery of the quartz vibrating piece;
In a crystal unit comprising a pair of sealing bodies each having a sealing frame in close contact with the upper and lower surfaces of the support frame and sealing the vibrating body,
The pair of sealing bodies are provided with a pair of reinforcing pieces that support the connecting piece so as to face at least a part of the connecting piece when the vibrating body is sandwiched, respectively. Crystal oscillator. A plate-like vibrating body having a connecting piece for supporting at least one end of the base part of the crystal vibrating piece having a base part and a pair of vibrating arm parts extending from the base part, and comprising a support frame surrounding the outer periphery of the crystal vibrating piece;
In a crystal resonator comprising a pair of sealing bodies each having a sealing frame in close contact with the upper and lower surfaces of the support frame and sandwiching the vibrating body,
The pair of sealing bodies is provided with a pair of reinforcing pieces for supporting the connecting piece so as to face at least a part of the connecting piece when the vibrating body is sandwiched. Vibrator. The connecting piece extends from one side of the support frame and connects to one end of the base, and extends between the pair of vibrating arms from the other side facing the one side of the support frame. A second connecting piece connected to the other end of the base,
The pair of sealing bodies includes a pair of reinforcements that support the first and second connecting pieces so as to face at least a part of the first and second connecting pieces when the vibrating body is sandwiched. The crystal unit according to claim 2, wherein a piece is provided.   The reinforcing piece has a length and a width corresponding to the connecting piece, and supports the connecting piece so as to face the entire connecting piece when the pair of sealing bodies sandwich the vibrating body. The crystal resonator according to claim 1.   5. The crystal resonator according to claim 1, wherein the reinforcing piece includes a connection portion between the crystal vibrating piece and the connecting piece, and faces the connecting piece.   6. The crystal resonator according to claim 1, wherein at least one of the pair of reinforcing pieces abuts and supports the opposing side of the connecting piece. At least one of the pair of reinforcing pieces is disposed in close proximity with a slight gap on the opposite side of the connecting piece ,
Quartz crystal resonator according to any of Der Ru claims 1 to 5 as the slight gap corresponding to the thickness of the bonding layer for bonding the sealing frame of the support frame and a pair of sealing body of the vibrator Child.   6. The crystal resonator according to claim 1, wherein at least one of the pair of reinforcing pieces is bonded to and supported on an opposite side of the connecting piece. The crystal unit according to claim 2 , wherein the connecting piece is connected to a base portion of the vibrating arm portion in a direction orthogonal to a direction in which the pair of vibrating arm portions extend.
  The said support frame and a pair of sealing frames have a square-shaped outer peripheral part and an inner peripheral part surrounding the said quartz crystal vibrating piece, The said inner peripheral part is formed in the curved surface shape. A crystal resonator according to any one of the above.   The crystal resonator according to claim 10, wherein the curved shape of the inner peripheral portion is a gourd shape or an egg shape.   4. The crystal resonator according to claim 1, wherein a metal plating layer or a resin coating layer is formed on a surface of the pair of sealing bodies facing a front surface and a back surface of the crystal resonator element.

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