JP2016054376A - Piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an appropriately packaged piezoelectric oscillator.SOLUTION: An oscillator 1 holds a wiring substrate 7 with an opening 37h which penetrates from the first principal surface 37a to the second principal surface 37b, a vibrator 3 which is mounted on the first principal surface 37a to cover the opening 37h, an integrated circuit element 5 which is placed inside the opening 37h and mounted on the vibrator 3. The wiring substrate 7 holds an insulation substrate 37 with the first principal surface 37a, the second principal surface 37b and the opening 37h, a pad for a vibrator 41 which is installed on the first principal surface 37a and on which a vibrator 3 is mounted, a solder resist 39 which exposes the pad for a vibrator 41 and covers the insulation substrate 37. The inner peripheral surface of the opening 37h holds the first non-arranged region R1 where the solder resist 39 is not arranged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piezoelectric oscillator such as a crystal oscillator.

  As a crystal oscillator having a crystal resonator element and an oscillation circuit (integrated circuit element) that generates an oscillation signal by applying a voltage to the crystal resonator element, for example, a first recess in which the crystal resonator element is accommodated in a first main surface Is known, and has a so-called H-type package in which a second concave portion for accommodating an integrated circuit element is formed on a second main surface on the back surface thereof. In this crystal oscillator, for example, the second main surface is opposed to the circuit board, and the pad formed around the second concave portion of the second main surface and the pad of the circuit board are joined by the bump, Mounted on a circuit board.

  A crystal resonator that includes a crystal resonator element and a package that accommodates the crystal resonator element and does not include an oscillation circuit (integrated circuit element) is also well known. Such a crystal resonator can be electrically connected to the integrated circuit element by being mounted on a wiring board on which the integrated circuit element is mounted, thereby forming a crystal oscillator.

JP 2000-49560 A

  The crystal oscillator having the H-type package described above is reduced in size because, for example, the package is integrated as a whole as compared with a configuration in which a crystal resonator is mounted on a wiring board on which an integrated circuit element is mounted. Etc. are advantageous. On the other hand, for example, when changing the joint (pad or the like) between the crystal oscillator and the circuit board on which the crystal oscillator is mounted, there arises a disadvantage that the design of the entire package needs to be changed.

  Accordingly, it is desirable to provide a suitably packaged piezoelectric oscillator.

  A piezoelectric oscillator according to an aspect of the present invention includes a wiring board having a first main surface, a second main surface on the back surface thereof, and an opening penetrating from the first main surface to the second main surface; A piezoelectric vibrator mounted on one main surface so as to cover the opening, and an integrated circuit element disposed in the opening and mounted on the piezoelectric vibrator, and the wiring board includes: An insulating substrate having one main surface, the second main surface and the opening; a vibrator pad provided on the first main surface on which the piezoelectric vibrator is mounted; and the vibrator pad is exposed. However, a solder resist that covers the insulating substrate is provided, and an inner peripheral surface of the opening has a first non-arrangement region in which the solder resist is not arranged.

  Preferably, the opening further includes an underfill filled between the piezoelectric vibrator and the integrated circuit element, and the piezoelectric vibrator forms a gap between the first main surface and the underfill. Mounted on the first main surface in a state where the solder resist is not arranged on the first main surface, and a second non-arrangement region connecting the opening and the vibrator pad is formed on the first main surface. And the underfill reaches the vibrator pad from the opening through the second non-arrangement region.

  Preferably, the first main surface has a third non-arrangement region in which the solder resist is not arranged, is adjacent to the vibrator pad and surrounds the vibrator pad, and the underfill is the first fill. 2 extends from the non-arrangement region to the third non-arrangement region.

  Preferably, the opening further includes an underfill filled between the piezoelectric vibrator and the integrated circuit element, and the piezoelectric vibrator forms a gap between the first main surface and the underfill. In this state, the first main surface is mounted on the first main surface, and the solder resist is not arranged on the first main surface, and has a fourth non-arrangement region adjacent to the opening and surrounding the opening. The underfill extends from the opening onto the fourth non-arrangement region.

  According to the above configuration, a suitably packaged piezoelectric oscillator is realized.

1 is an exploded perspective view showing a schematic configuration of a crystal oscillator according to an embodiment of the present invention. Sectional drawing in the II-II line of FIG. 3A and 3B are plan views of the front and back of the substrate portion of the crystal oscillator of FIG. The top view of the wiring board of the crystal oscillator of FIG. 5A is an enlarged view of a region V in FIG. 2, and FIG. 5B is a diagram corresponding to FIG. 5A of a crystal oscillator according to a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings used in the following description are schematic, and the dimensional ratios and the like on the drawings do not necessarily match the actual ones.

  Further, for the purpose of clarifying the relationship between the drawings, the rectangular coordinate system xyz may be attached to the drawings for the sake of convenience. The x-axis, y-axis, and z-axis are defined for convenience based on the shape of the member and the like, and do not mean the electric axis, mechanical axis, and optical axis of the piezoelectric body (quartz).

(Configuration of crystal oscillator)
FIG. 1 is an exploded perspective view showing a schematic configuration of a crystal oscillator 1 (hereinafter, “crystal” is omitted) according to an embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG.

  The oscillator 1 is, for example, an electronic component that is generally thin and has a thin rectangular parallelepiped shape as a whole, and the dimensions thereof may be set as appropriate. For example, in a comparatively small thing, the length of a long side or a short side is 1-2 mm, and thickness is 0.2-0.4 mm.

  The oscillator 1 includes, for example, a crystal resonator 3 (hereinafter, “crystal” is omitted), an integrated circuit element 5 mounted on the resonator 3, and a wiring board 7 on which the resonator 3 is mounted. .

  When an alternating voltage is applied, the vibrator 3 generates a natural vibration therein. The integrated circuit element 5 includes an oscillation circuit, applies a voltage to the vibrator 3, and generates an oscillation signal using the natural vibration in the vibrator 3. The wiring board 7 is connected to a circuit board (not shown) or the like, and mediates an electrical signal between the circuit board and the integrated circuit element 5 through the package of the vibrator 3. These specific configurations are, for example, as follows.

  The vibrator 3 includes, for example, a crystal vibration element 9 (hereinafter, “crystal” is omitted), an element mounting member 11 that houses the vibration element 9, and a lid member 13 that seals the element mounting member 11. . The element mounting member 11 and the lid member 13 constitute a package of the vibrator 3.

  The vibration element 9 includes, for example, a crystal piece 15, a pair of excitation electrodes 17 for applying a voltage to the crystal piece 15, and a pair of extraction electrodes 19 for mounting the vibration element 9 on the element mounting member 11. have.

  The crystal piece 15 is formed in a substantially rectangular plate shape, for example. The crystal piece 15 is made of, for example, an AT cut crystal piece. The pair of excitation electrodes 17 is provided in a layered manner on the center side of both main surfaces of the crystal piece 15, for example. For example, the pair of extraction electrodes 19 are extracted from the pair of excitation electrodes 17 and provided at one end side portion in the longitudinal direction of the crystal piece 15. The pair of excitation electrodes 17 and the pair of extraction electrodes 19 are, for example, center lines (not shown) extending in the longitudinal direction of the crystal piece 15 so that either of the main surfaces of the vibration element 9 may be the mounting side. Is formed in a 180 ° rotationally symmetric shape.

  The element mounting member 11 includes, for example, an insulating base 21 and various conductors (for example, metal) provided on the base 21. The various conductors include, for example, a pair of element mounting pads 23 for mounting the vibration element 9 on the element mounting member 11 and a plurality of (four in this embodiment) for mounting the vibrator 3 on the wiring board 7. The vibrator terminals 25 and a plurality (six in this embodiment) of IC pads 26 (FIG. 2) for mounting the integrated circuit element 5 on the vibrator 3.

  The base 21 is made of, for example, ceramic and has a concave portion 21r that accommodates the vibration element 9. The base 21 includes, for example, a flat plate-like substrate portion 21a and a frame portion 21b overlapped with the substrate portion 21a, thereby forming a recess 21r.

  For example, the pair of element mounting pads 23 are provided in a layered manner on the bottom surface of the recess 21r (the main surface of the substrate portion 21a on the frame portion 21b side). The plurality of transducer terminals 25 are provided in a layered manner at, for example, the four corners of the main surface of the substrate portion 21a opposite to the frame portion 21b (see FIG. 3B). The plurality of IC pads 26 are arranged in, for example, two rows in a region surrounded by the plurality of transducer terminals 25 on the main surface of the substrate portion 21a opposite to the frame portion 21b (FIG. 3 ( b)).

  The vibration element 9 is fixed to the element mounting member 11 like a cantilever by joining a pair of extraction electrodes 19 and a pair of element mounting pads 23 by a pair of bumps 27 (FIG. 2). And electrically connected to the element mounting member 11. The bump 27 is made of, for example, a conductive adhesive.

  The lid member 13 is made of metal, for example. The lid member 13 is joined to the frame portion 21b of the element mounting member 11, whereby the concave portion 21r is sealed. The inside of the recess 21r is, for example, a vacuum or an appropriate gas (for example, nitrogen) is sealed.

  The lid member 13 and the element mounting member 11 may be joined by an appropriate method. For example, a frame-shaped first bonding pattern 29 made of metal is formed on the surface of the frame portion 21b on the lid member 13 side. On the other hand, a frame-shaped second bonding pattern 31 made of metal is formed on the surface of the lid member 13 on the frame portion 21b side. And the cover member 13 and the element mounting member 11 are mutually joined by joining both by seam welding.

  The integrated circuit element 5 is formed in, for example, a substantially thin rectangular parallelepiped shape, and has a plurality (six in this embodiment) of IC terminals 33 on one main surface. The integrated circuit element 5 is fixed to the element mounting member 11 by bonding the IC terminal 33 and the aforementioned IC pad 26 provided on the element mounting member 11 by the bump 35 (FIG. 2). The element mounting member 11 is electrically connected.

  The number and role of the IC terminals 33 may be set as appropriate according to functions required for the oscillator 1. For example, one of the six IC terminals 33 is for supplying a reference potential to the integrated circuit element 5, and one supplies a power supply voltage (potential different from the reference potential) to the integrated circuit element 5. Two are for applying a voltage from the integrated circuit element 5 to the vibration element 9, and one is for inputting a control signal for adjusting the frequency of the oscillation signal to the integrated circuit element 5. One is for inputting an enable / disable signal to the integrated circuit element 5 to instruct generation or stop of the oscillation signal by the integrated circuit element 5.

  As already described, the integrated circuit element 5 includes an oscillation circuit. The oscillation circuit is, for example, a feedback type. The integrated circuit element 5 may include a temperature sensor and a temperature compensation circuit that compensates for a temperature change of the oscillation signal based on the temperature detected by the temperature sensor. The integrated circuit element 5 may be packaged or a bare chip.

  For example, the wiring board 7 may have the same configuration as a rigid printed wiring board. For example, the wiring substrate 7 includes an insulating substrate 37, various conductors (for example, metal) provided on the insulating substrate 37, and a solder resist 39 for reducing short-circuiting of the various conductors. The various conductors include, for example, a plurality (four in this embodiment) of vibrator pads 41 for mounting the vibrator 3 on the wiring board 7 and a plurality of parts for mounting the wiring board 7 on a circuit board (not shown). (In this embodiment, four) external terminals 43 and a plurality (four in this embodiment) of through-hole conductors 45 (FIG. 1) connecting the plurality of vibrator pads 41 and the plurality of external terminals 43. It is.

  The insulating substrate 37 is made of, for example, a glass epoxy material. The insulating substrate 37 (wiring substrate 7) has a first main surface 37a, a second main surface 37b on the back surface thereof, and an opening 37h penetrating from the first main surface 37a to the second main surface 37b. . The planar shapes of the insulating substrate 37 and the opening 37h may be set as appropriate. For example, the outer shape of the insulating substrate 37 is rectangular. Further, for example, the shape of the opening 37h is a rectangle with chamfered corners.

  The plurality of vibrator pads 41 are provided in a layered manner on the four corners of the first main surface 37a, for example, and surround the opening 37h. The plurality of external terminals 43 are, for example, provided in layers at the four corners of the second main surface 37b and surround the opening 37h. The through-hole conductor 45 is located, for example, on the four corners of the first main surface 37a with respect to the plurality of vibrator pads 41, and penetrates the insulating substrate 37 from the first main surface 37a to the second main surface 37b. Is provided in a layered manner on the inner peripheral surface.

  The planar shape of the vibrator pad 41 and the external terminal 43 and the shape of the connection conductor between them and the through-hole conductor 45 may be set as appropriate. In the present embodiment, the vibrator pad 41 and the external terminal 43 are rectangular, and are directly connected to a circular land around the through hole. In addition, as for the part (corner part) by the side of the opening part 37h of the some oscillator pads 41 and the external terminal 43, the corner part of the opening part 37h is chamfered because the corner part of the opening part 37h is chamfered. It is located closer to the opening 37h side than the virtual corner when there is not.

  The solder resist 39 is generally made of a thermosetting resin (for example, epoxy resin) containing a pigment or the like. However, in the present application, the term “solder resist” broadly refers to a film made of an insulating resin, and does not need to include, for example, a pigment. For example, the solder resist 39 covers the first main surface 37a while exposing the plurality of vibrator pads 41. The solder resist 39 may cover the second main surface 37b while exposing the external terminals 43, or may cover the side surface of the insulating substrate 37.

  The vibrator 3 is bonded to the wiring substrate 7 by bonding the plurality of vibrator terminals 25 provided on the element mounting member 11 and the vibrator pad 41 with bumps 47 (FIG. 2). It is fixed and electrically connected. Since the vibrator pad 41 is disposed so as to surround the opening 37h, the vibrator 3 is mounted on the wiring board 7 so as to cover the opening 37h from the first main surface 37a side. The area of the vibrator 3 is larger than the area of the opening 37h, for example, and the opening 37h fits in the vibrator 3 in plan view.

  The integrated circuit element 5 mounted in the region surrounded by the vibrator pad 41 of the vibrator 3 is accommodated in the opening 37h. In FIG. 2, the top surface of the integrated circuit element 5 (z-direction negative surface) is located on the inner side (z-direction positive side) than the second main surface 37 b. It may be substantially flush with the second main surface 37b.

As shown in FIG. 2, an underfill 49 is filled between the integrated circuit element 5 and the vibrator 3. The underfill 49 is made of, for example, a thermosetting resin (for example, an epoxy resin). The underfill 49 may include a filler (for example, made of SiO ₂ ) having a lower thermal expansion coefficient than that of the resin. The underfill 49 may be provided so as to cover the side surface of the integrated circuit element 5 to an appropriate height, or may be provided so as to cover not only the side surface but also the top surface of the integrated circuit element 5.

  The base 21 of the element mounting member 11 (vibrator 3) faces the insulating substrate 37 of the wiring substrate 7 with a gap corresponding to the thickness of the transducer terminal 25, the bump 47, and the transducer pad 41. The underfill 49 also extends from the opening 37 h to the gap between the base 21 and the insulating substrate 37.

  In the element mounting member 11, two of the six IC pads 26 and a pair of element mounting pads 23 are connected. Thus, the integrated circuit element 5 mounted on the IC pad 26 and the vibration element 9 mounted on the element mounting pad 23 are electrically connected. As a result, the integrated circuit element 5 can apply a voltage to the vibration element 9 to generate an oscillation signal.

  In the element mounting member 11, the remaining four of the six IC pads 26 and the four transducer terminals 25 are connected. Thereby, the integrated circuit element 5 mounted on the IC pad 26 and the wiring board 7 having the vibrator pad 41 to which the vibrator terminal 25 is bonded are electrically connected. As a result, electrical signals can be input / output to / from the integrated circuit element 5 by inputting / outputting electrical signals to / from the four external terminals 43 of the wiring board 7 connected to the vibrator pads 41 via the through-hole conductors 45. It is possible.

  3A and 3B are diagrams for explaining an example of the connection in the element mounting member 11 as described above. FIG. 3A shows the substrate portion 21a viewed from the vibration element 9. FIG. 3B is a plan view of the substrate portion 21a viewed from the integrated circuit element 5 side.

  As shown in FIG. 3A, a pair of first connection patterns 51 extend from a pair of element mounting pads 23 and are connected to a pair of first via conductors 53. As shown in FIG. 3B, the pair of first via conductors 53 penetrates the substrate portion 21 a in the thickness direction and is connected to the pair of second connection patterns 55. The pair of second connection patterns 55 are connected to the two IC pads 26. Further, as shown in FIG. 3B, the remaining four IC pads 26 are connected to the four transducer terminals 25 via the four third connection patterns 57.

  The first connection pattern 51, the second connection pattern 55, and the third connection pattern 57 are formed in layers. The first connection pattern 51 may partially overlap the frame portion 21b. The reason why the middle of the pair of second connection patterns 55 is wide is to make a probe of an inspection apparatus that inspects characteristics of the vibration element 9 abut in the manufacturing process of the oscillator 1. The second via conductor 59 is for connecting the vibrator terminal 25 to which the reference potential is applied and the lid member 13 made of a conductor, and the frame portion 21b also penetrates in the thickness direction.

  FIG. 4 is a plan view of the wiring board 7 on the first main surface 37a side.

  As shown in FIGS. 1 and 4, the wiring substrate 7 is provided with a non-arrangement region of the solder resist 39 in addition to the arrangement region of the vibrator pad 41. Specifically, it is as follows.

  First, the inner peripheral surface of the opening 37h has a first non-arrangement region R1 in which the solder resist 39 is not disposed. The first non-arrangement region R1 is, for example, the entire inner peripheral surface of the opening 37h.

  The first main surface 37a is adjacent to the second non-arrangement region R2 connecting the opening 37h and the vibrator pad 41 and the vibrator pad 41 as a non-placement area in which the solder resist 39 is not disposed, and is used for the vibrator. A third non-arrangement region R3 surrounding the pad 41 and a fourth non-arrangement region R4 adjacent to the opening 37h and surrounding the opening 37h are provided.

  In the present embodiment, the second non-arrangement region R2 is configured by an intersection of the third non-arrangement region R3 and the fourth non-arrangement region R4 (in the third non-arrangement region R3 and the fourth non-arrangement region R4). include.).

  The third non-arrangement region R3 has, for example, a shape (groove shape) extending along the edge of the transducer pad 41 with a substantially constant width. The third non-arrangement region R3 surrounds the vibrator pad 41 except for, for example, a connection portion between the vibrator pad 41 and the through-hole conductor 45. Note that “enclose” here means that, for example, the third non-arrangement region R <b> 3 may extend over half or more of the edge of the transducer pad 41.

  For example, the fourth non-arrangement region R4 has a shape (groove shape) extending along the edge of the opening 37h with a substantially constant width. The extending shape may be discrete like a dotted line. For example, the fourth non-arrangement region R4 surrounds the entire opening 37h. Note that “enclose” here means, for example, that one or more fourth non-arranged regions R4 extend over half or more of the edge of the opening 37h, or the central angle of the edge of the opening 37h is 120 ° or less. It is only necessary that the fourth non-arrangement region R4 is located in at least a part of each section divided into three equal parts or more.

  The widths of the second non-arrangement region R2 to the fourth non-arrangement region R4 may be set as appropriate. For example, these widths are 30 μm or more and 200 μm or less. These widths may be smaller or larger than the thickness of the solder resist 39.

  FIG. 5A is an enlarged view of a region V in FIG.

  For example, the solder resist 39 is formed thicker than the vibrator pad 41 (and the conductive layer on the other first main surface 37a). For example, the thickness of the vibrator pad 41 is not less than 10 μm and not more than 40 μm, whereas the thickness of the solder resist 39 is not less than 5 μm and not less than 15 μm and not more than 100 μm.

  As described above, the underfill 49 extends from the opening 37 h to the gap between the base 21 of the element mounting member 11 and the insulating substrate 37 of the wiring substrate 7. More specifically, the underfill 49 extends between the base 21 and the insulating substrate 37 in the second non-arrangement region R2 to the fourth non-arrangement region R4, and is in close contact with these members. Further, the underfill 49 is in close contact with the vibrator pad 41, the bump 47 and the vibrator terminal 25. Although not particularly illustrated, the underfill 49 may be spread between the solder resist 39 and the base 21 and may be in close contact with these members.

(Manufacturing method of crystal oscillator)
A method of manufacturing a crystal oscillator having the above configuration will be described.

  First, each member shown in the exploded perspective view of FIG. 1, that is, the wiring board 7, the integrated circuit element 5, the element mounting member 11, the vibration element 9, and the lid member 13 are prepared. The manufacturing method of each of these members may be the same as a known method except for a specific shape.

  Next, each member is joined. That is, the vibration element 9 is bonded to the element mounting member 11, the lid member 13 is bonded to the element mounting member 11, the integrated circuit element 5 is bonded to the element mounting member 11, and the element mounting member 11 is bonded to the wiring substrate 7. Is called.

  As long as the joining of the lid member 13 to the element mounting member 11 is after the joining of the vibration element 9 to the element mounting member 11, any joining order is possible. Further, the characteristics of the vibration element 9 are inspected through a measurement pad (in this embodiment, the integrated circuit element 5 overlaps) formed by expanding a part of the second connection pattern 55, and the excitation electrode 17 of the excitation electrode 17 is responded accordingly. In the case of adjusting the weight, the bonding of the integrated circuit element 5 to the element mounting member 11 is after the bonding of the vibration element 9 to the element mounting member 11 and more than the bonding of the lid member 13 to the element mounting member 11. It is before.

  Next, uncured underfill 49 is filled between the integrated circuit element 5 and the vibrator 3 through the opening 37h. Filling is performed by, for example, a dispenser.

  At this time, the uncured underfill 49 has higher wettability with respect to the insulating substrate 37 (first main surface 37 a) than wettability with respect to the solder resist 39. And / or, in a non-arrangement region of the solder resist 39, in a corner formed by the first main surface 37a and the side surface of the solder resist 39, or in a groove formed by the first main surface 37a and the two side surfaces of the solder resist 39. Causes a capillary phenomenon that pulls in the solder resist 39. As a result, the underfill 49 preferentially spreads on the second non-arrangement region R2 to the fourth non-arrangement region R4 rather than on the solder resist 39.

  Thereafter, the underfill 49 is hardened in a normal temperature atmosphere or by heating in a reflow furnace or the like.

(Modification)
FIG. 5B is a cross-sectional view corresponding to FIG.

  In this modification, the second non-arrangement region R2 to the fourth non-arrangement region R4 are not formed. In this case, when the uncured underfill 49 is supplied to the opening 37 h, the solder resist 39 located on the opening 37 h side functions as a weir against the flow that travels through the first main surface 37 a of the underfill 49. As a result, the underfill 49 does not reach the vibrator pad 41.

  As described above, in this embodiment, the oscillator 1 covers the wiring board 7 having the opening 37h penetrating from the first main surface 37a to the second main surface 37b, and the first main surface 37a covers the opening 37h. It has the mounted vibrator 3 and the integrated circuit element 5 disposed in the opening 37 h and mounted on the vibrator 3. The wiring substrate 7 includes an insulating substrate 37 having a first main surface 37a, a second main surface 37b, and an opening 37h, a vibrator pad 41 provided on the first main surface 37a, on which the vibrator 3 is mounted, And a solder resist 39 that covers the insulating substrate 37 while exposing the vibrator pad 41. The inner peripheral surface of the opening 37h has a first non-arrangement region R1 in which the solder resist 39 is not arranged.

  Therefore, for example, the package of the oscillator 1 can be configured by a combination of the package of the vibrator 3 (the element mounting member 11 and the lid member 13) and the wiring board 7. As a result, for example, the arrangement and size of the external terminals 43 can be easily changed by changing or replacing the wiring board 7. Further, for example, the integrated circuit element 5 is accommodated in the opening 37h as compared with the case where both the vibrator and the integrated circuit element are mounted on the wiring board to constitute the oscillator, and thus the size can be reduced.

  Further, since the solder resist 39 is not disposed on the inner peripheral surface of the opening 37h, the inner diameter of the opening 37h can be increased by twice the thickness of the solder resist 39, and accordingly the opening 37h The area can be increased. As a result, the wiring board 7 can be downsized or the large integrated circuit element 5 can be mounted.

  In the present embodiment, the oscillator 1 further includes an underfill 49 filled between the vibrator 3 and the integrated circuit element 5 in the opening 37h. The vibrator 3 is mounted on the first main surface 37a in a state where a gap is formed between the vibrator 3 and the first main surface 37a. The first main surface 37a has a second non-arrangement region R2 in which the solder resist 39 is not arranged and connects the opening 37h and the vibrator pad 41. The underfill 49 reaches the vibrator pad 41 from the opening 37h via the second non-arrangement region R2.

  Therefore, for example, the insulating substrate 37 and the vibrator 3 can be bonded by the underfill 49 for sealing the integrated circuit element 5 to improve the bonding strength between the two. Since the bonding strength is improved in the second non-arrangement region R2 extending to the vibrator pad 41, the reliability of electrical connection between the vibrator pad 41 and the vibrator terminal 25 can be improved. As a result, for example, the reliability of the oscillator 1 can be improved at a low cost and in a small size. As can be understood from the comparison with the modified example of FIG. 5B, the formation of the second non-arrangement region R2 allows the underfill 49 to reach the vibrator pad 41 more reliably. .

  In the present embodiment, in addition to the second non-arrangement region R2, the first main surface 37a is not disposed with the solder resist 39, and is adjacent to the transducer pad 41 and surrounds the transducer pad 41. A third non-arrangement region R3 is included. The underfill 49 extends from the second non-arrangement region R2 to the third non-arrangement region R3.

  Accordingly, for example, the bonding strength between the insulating substrate 37 and the vibrator 3 by the underfill 49 is improved around the vibrator pad 41. As a result, the reliability of the electrical connection between the vibrator pad 41 and the vibrator terminal 25 can be further improved.

  Further, in the present embodiment, the first main surface 37a has a fourth non-arrangement region R4 in which the solder resist 39 is not disposed and is adjacent to the opening 37h and surrounds the opening 37h. The underfill 49 extends from the opening 37h to the fourth non-arrangement region R4.

  Therefore, for example, the underfill 49 in close contact with the integrated circuit element 5 engages with the wiring substrate 7 from the first main surface 37a side to the second main surface 37b side. As a result, for example, a force that pulls the IC terminal 33 of the integrated circuit element 5 away from the IC pad 26 of the vibrator 3 is suppressed from being applied to the IC terminal 33. That is, the reliability of the electrical connection of the oscillator 1 can be improved only by forming the fourth non-arrangement region R4.

  In the above embodiment, the crystal oscillator 1 is an example of a piezoelectric oscillator, and the crystal resonator 3 is an example of a piezoelectric resonator.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The piezoelectric oscillator is not limited to one using crystal, and may be one using ceramic, for example. The use or function of the piezoelectric oscillator may be set as appropriate. For example, the piezoelectric oscillator may be a clock oscillator, a voltage controlled oscillator (for example, VCXO), a temperature compensated oscillator (for example, TCXO), or a thermostatic oscillator. It may be an oscillator in a constant temperature bath (for example, OCXO). The number and arrangement of external terminals, vibrator pads, vibrator terminals, IC pads, and IC terminals may be appropriately set according to functions required for the piezoelectric oscillator.

  The specific configuration of the piezoelectric vibrator may be changed as appropriate. For example, the piezoelectric vibrating element may be of a tuning fork type having two vibrating arms, or a pair of extraction electrodes formed on a rectangular flat plate diagonal. For example, the element mounting member may have a frame portion made of metal.

  The specific configuration of the wiring board may be changed as appropriate. For example, the vibrator pad and the external terminal may be connected not by a layered through-hole conductor but by a via conductor filled in a via penetrating the insulating substrate. Further, for example, the wiring board may have not only the main surface but also a conductor layer parallel to the main surface inside. For example, the wiring board may have a layered wiring or the like on the first main surface and / or the second main surface, and may have a solder resist so as to cover the wiring or the like.

  The wiring substrate is not limited to a configuration having an insulating substrate having a size substantially equal to that of the vibrator in plan view and a layered external terminal provided on the second main surface. In other words, the wiring board is not limited to one that forms a shape like a so-called H-type package with the vibrator package. For example, the wiring board may have a relatively large area, and an appropriate electronic component may be mounted on the first main surface in parallel with the vibrator. For example, the wiring board may be one in which an electronic component such as a heater is mounted on the second main surface so as to cover the opening. Further, for example, the wiring board may be one in which a pin-like external terminal is inserted into and fixed to the through-hole conductor (45) instead of providing a layered external terminal on the second main surface.

  The wiring board does not have to be formed in all of the first non-arrangement region to the fourth non-arrangement region. For example, only one of the first non-arranged region to the fourth non-arranged region, any two, or only three may be formed. However, in consideration of the flow of uncured underfill through the insulating substrate, the second non-arranged region to the fourth non-arranged region are preferably combined with the first non-arranged region, and the third non-arranged region The region is preferably combined with the second non-arranged region.

  The shape of each non-arrangement region may be set as appropriate. For example, the first non-arrangement region may be formed not only on the entire inner peripheral surface of the opening but only on a part in the circumferential direction and / or a part in the penetration direction. Further, for example, the second non-arrangement region may have a linear shape extending from the opening to the vibrator pad. Further, for example, the second non-arrangement region (and the third non-arrangement region) may have a shape that extends from the opening to the transducer pad with the same width as the transducer pad. Further, for example, the third non-arrangement region may have a shape that surrounds the vibrator pad with a relatively wide width to the extent that it cannot be said that the third non-arrangement region extends along the edge of the vibrator pad. Further, for example, the fourth non-arrangement region may be provided in a distributed manner at a plurality of positions on the edge of the opening, not over the entire circumference of the opening.

  In addition, it is preferable that a solder resist is located between the plurality of vibrator pads, and the short circuit between the vibrator pads is suppressed by the solder resist.

  DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator (piezoelectric oscillator), 3 ... Crystal oscillator (piezoelectric vibrator), 5 ... Integrated circuit element, 7 ... Wiring board, 37 ... Insulating board, 37a ... 1st main surface, 37b ... 2nd main surface, 37h ... opening, 39 ... solder resist, 41 ... vibrator pad, R1 ... first non-arrangement region.

Claims (4)

A wiring board having a first main surface, a second main surface on the back surface thereof, and an opening penetrating from the first main surface to the second main surface;
A piezoelectric vibrator mounted on the first main surface so as to cover the opening;
An integrated circuit element disposed in the opening and mounted on the piezoelectric vibrator;
Have
The wiring board is
An insulating substrate having the first main surface, the second main surface and the opening;
A vibrator pad provided on the first main surface on which the piezoelectric vibrator is mounted;
A solder resist that covers the insulating substrate while exposing the vibrator pad, and
An inner peripheral surface of the opening has a first non-arrangement region in which the solder resist is not arranged. Piezoelectric oscillator. An underfill filled between the piezoelectric vibrator and the integrated circuit element in the opening;
The piezoelectric vibrator is mounted on the first main surface in a state where a gap is formed between the piezoelectric vibrator and the first main surface.
The first main surface has a second non-arrangement region in which the solder resist is non-arranged and connects the opening and the vibrator pad,
The piezoelectric oscillator according to claim 1, wherein the underfill reaches the vibrator pad from the opening through the second non-arrangement region. The first main surface has a third non-arrangement region in which the solder resist is not arranged, is adjacent to the vibrator pad and surrounds the vibrator pad,
The piezoelectric oscillator according to claim 2, wherein the underfill extends from the second non-arrangement region to the third non-arrangement region. An underfill filled between the piezoelectric vibrator and the integrated circuit element in the opening;
The piezoelectric vibrator is mounted on the first main surface in a state where a gap is formed between the piezoelectric vibrator and the first main surface.
The first main surface has a fourth non-arrangement region in which the solder resist is not arranged and is adjacent to the opening and surrounds the opening.
The piezoelectric oscillator according to claim 1, wherein the underfill extends from the opening to the fourth non-arranged region.

Images