JP6569267B2 - Piezoelectric oscillator - Google Patents

Description

  The present invention relates to a surface mount type piezoelectric oscillator.

  As a piezoelectric vibration device, for example, a surface-mount type crystal resonator or a crystal oscillator is widely used. For example, in a surface-mount type crystal oscillator, a piezoelectric vibration element made of crystal or the like and an electronic component element such as an IC (integrated circuit element) are mounted in a recess provided in a base (container) made of an insulating material. The recess is hermetically sealed with a lid. A plurality of external connection terminals are formed on the outer bottom surface of the base, and some of these external connection terminals are electrically connected to the piezoelectric vibration element and the IC. The piezoelectric oscillator is mounted on the external circuit board by being electrically and mechanically bonded to the mounting pad on the external circuit board with a conductive bonding material such as solder at the external connection terminal.

  Among such piezoelectric oscillators, there is a so-called H-type package structure in which a crystal resonator element and an IC are accommodated in separate spaces, as disclosed in Patent Document 1. More specifically, the crystal oscillator described in Patent Document 1 has a structure in which a crystal piece (piezoelectric vibration element) is sealed on one side of a cavity (concave portion) on the front and back of a container, and an IC is mounted on the other side. ing. The external connection terminal is formed on the upper surface (the bottom surface of the crystal oscillator) of the frame portion surrounding the cavity on the side where the IC is mounted.

JP 2009-27469 A

  In the piezoelectric oscillator as described above, since the piezoelectric vibration element and the IC are accommodated in different spaces, it can be made less susceptible to the effects of gas generated during the manufacturing process and noise generated from other elements. There are benefits. On the other hand, since environmental conditions such as temperature may be different within each expropriation part, there may be some errors in the environment such as temperature applied to each element housed in a separate space as described above. . In particular, the temperature tends to vary in each storage portion due to the influence of heat transmitted from the external environment of the package and the influence of heat generation of the element itself.

  For example, in a crystal oscillator (so-called TCXO) having a temperature compensation function as a piezoelectric oscillator, a crystal vibration element having frequency temperature characteristics is stored in one storage unit, and an oscillation circuit, a temperature compensation circuit, and a temperature detection unit are stored in the other storage unit. The IC having the is stored. Since the IC generates heat during operation, there is a problem in that accurate temperature compensation cannot be performed if there is a difference between the temperature applied to the crystal resonator element and the temperature applied to the temperature detection unit of the IC.

  The present invention has been made in view of such points, and in a piezoelectric oscillator in which a piezoelectric vibration element and an IC having a temperature detection unit are housed in separate spaces, temperature differences between the elements in the separate spaces are eliminated, and temperature conditions It is an object of the present invention to provide a piezoelectric oscillator with improved electrical property stability.

In order to achieve the above object, the present invention provides a substrate portion whose upper side is one main surface and whose lower side is the other main surface;
A first frame portion extending upward from an outer peripheral portion of one main surface of the substrate portion, a second frame portion extending downward from an outer peripheral portion of the other main surface of the substrate portion, and the second frame portion. An external connection terminal, a piezoelectric vibration element mounted in a first recess surrounded by the first frame portion and one main surface of the substrate portion , the second frame portion and the substrate. In a piezoelectric oscillator comprising: an IC having a temperature detection unit mounted in a second recess surrounded by the other main surface of the unit; and a lid for hermetically sealing the piezoelectric vibration element, an inner bottom surface of the second recess Are formed with a plurality of wiring patterns for electrically and mechanically joining the IC, and the plurality of wiring patterns include a plurality of piezoelectric vibration element connecting wiring patterns connected to the piezoelectric vibration elements and the external connection terminals. a plurality of external connection terminals connecting the wiring pattern to be connected to is formed, the 1 on the inner bottom surface of the recess, the piezoelectric vibrating element has a first wiring pattern for a plurality of piezoelectric vibrating elements connected electrically and mechanically junction is formed, and of the first wiring pattern for the piezoelectric vibrating element connected The extending end portion of the central portion of the inner bottom surface of the first recess and the piezoelectric vibration element connecting wiring pattern on the inner bottom surface of the second recess are connected by a conductive via for piezoelectric vibration element connection penetrating in the thickness direction of the substrate portion. The piezoelectric vibration element connecting wiring patterns are formed between the external connecting terminal connecting wiring patterns, and each piezoelectric connecting element has an area corresponding to the area of each of the external connecting terminal connecting wiring patterns. The area of the vibration element connecting wiring pattern is smaller.

  According to the above invention, the area of each of the piezoelectric vibration element connecting wiring patterns is made smaller than the area of each of the external connecting terminal connecting wiring patterns, so that heat from the IC is not dissipated. The piezoelectric vibration element connecting conductive via can be quickly transmitted to the piezoelectric vibration element via the piezoelectric vibration element connecting first wiring pattern from the piezoelectric vibration element connecting conductive via. As a result, a temperature difference between the IC and the piezoelectric vibration element can be hardly generated. In addition, the adverse effect of stray capacitance on the piezoelectric vibration element can be reduced more effectively.

  By configuring the area of each of the external connection terminal connection wiring patterns to be larger than the area of each of the piezoelectric vibration element connection wiring patterns, a part of the heat generated in the IC is connected to the external connection terminal connection wiring. It is possible to radiate heat to the pattern, and to suppress the unilateral temperature rise of only the IC with respect to the piezoelectric vibration element. In addition, since the connection area between the IC and the wiring pattern can be secured by the external connection terminal connection wiring pattern, the reliability of the connection between the IC and the wiring pattern can be improved. The reliability of connection between the IC and the wiring pattern can be improved.

  Further, in the above configuration, the IC and the wiring pattern may be electrically and mechanically joined via a metal bump.

  In this case, in addition to the above-described effects, the heat transfer between the IC and the piezoelectric vibration element can be enhanced, so that the temperature difference between the IC and the piezoelectric vibration element can be made even more difficult to occur.

  As described above, the present invention has been made in view of such a point, and in the piezoelectric oscillator in which the piezoelectric vibration element and the IC having the temperature detection unit are housed in different spaces, the temperature difference between the elements in the different spaces. Thus, it is possible to provide a piezoelectric oscillator in which the stability of electrical characteristics with temperature conditions is improved.

It is sectional drawing which shows schematic structure of the crystal oscillator which concerns on embodiment of this invention. It is a bottom view which shows schematic structure of the crystal oscillator which concerns on embodiment of this invention. FIG. 3 is a bottom view of a state where the IC of FIG. 2 is not mounted. FIG. 4 is a partially enlarged view of FIG. 3. It is a side view of the P direction of FIG. 1, FIG. It is the perspective view which showed the external view of the conductive via of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments of the present invention described below, as a piezoelectric oscillator, for example, a surface mounted temperature compensated crystal oscillator (so-called TCXO) including an IC including an oscillation circuit, a temperature detection unit, and a temperature compensation circuit will be described as an example. .

  An embodiment of the present invention will be described with reference to FIGS. The crystal oscillator 1 is a substantially rectangular parallelepiped package, and is substantially rectangular in a plan view and substantially H-shaped in cross section. The crystal oscillator 1 includes a base 2, a crystal resonator element 3, an IC 4, and a lid 5 as main constituent members. In this embodiment, the external size of the crystal oscillator 1 in plan view is about 1.6 mm × 1.2 mm in length and width, and the crystal oscillator 1 includes an IC 4 having an oscillation circuit as an electronic component element. Note that the external size of the above-described crystal oscillator in plan view is an example, and the present invention can be applied to package sizes other than the external size. Hereinafter, the outline of each member constituting the crystal oscillator 1 will be described in detail.

  The base 2 is a substantially rectangular container in plan view having a long side and a short side made of an insulating material. The base 2 has a flat plate-shaped (substantially rectangular in plan view) substrate portion 20 and extends upward along the outer peripheral portion 200 of one main surface 201 of the substrate portion 20, and an outer peripheral edge 210 and an inner peripheral edge 211 are substantially rectangular in a plan view. Main components are the first frame portion 21 and the second frame portion 22 that extends downward along the outer peripheral portion 200 of the other main surface 202 of the substrate portion 20 and has an outer peripheral edge 220 and an inner peripheral edge 221 that are substantially rectangular in plan view. (The cross section is substantially H-shaped).

  In the present embodiment, as a more preferable form, the substrate portion 20, the first frame portion 21, and the second frame portion 22 are each formed in a rectangular shape whose outer peripheral edges are substantially the same in plan view, and circles only at the four corners of each outer peripheral edge. Arc-shaped notches 20c, 21c, and 22c are formed. That is, the notches 20c1, 20c2, 20c3, and 20c4 are provided at the four corners of the outer peripheral edge of the substrate portion 20, and the notches 21c1, 21c2, 21c3, and 21c4 are provided at the four corners of the outer peripheral edge of the first frame portion 21. Cutout portions 22c1, 22c2, 22c3, and 22c4 are formed at the four corners of the outer peripheral edge of the frame portion 22. For this reason, even if the width of the first frame portion 21 and the second frame portion 22 is reduced due to miniaturization, by forming the notches 20c, 21c, and 22c only at the four corners that have a margin in width, The overall strength of the base is not reduced. In addition, since the sealing area between the first frame portion 21 and the lid 5 is not narrowed more than necessary, the hermetic sealing performance of the crystal resonator element 2 is not deteriorated.

  In this embodiment, each of the substrate part 20, the first frame part 21, and the second frame part 22 is a ceramic green sheet (alumina), and these three sheets are laminated and integrally formed by firing. Yes. Each of these sheets (substrate section sheet, first frame section sheet, second frame section sheet) is divided not only into a single layer but also into a plurality of layers according to the extension form of the internal wiring between the layers. May be formed.

  A sealing portion 6 is formed on the upper surface of the first frame portion 21 of the base 2. The sealing portion 6 is bonded to the metal lid 5 with a bonding material such as a gold-tin brazing material.

  A space surrounded by the inner peripheral edge 211 of the first frame portion 21 of the base 2 and the one principal surface 201 of the substrate portion is a first recess 2A. The first recess 2 </ b> A is substantially rectangular in plan view and has the same shape as the inner peripheral edge 211 of the first frame portion 21. A pair of crystal mounting pads 7a and 7b that are conductively bonded to the crystal resonator element 3 are formed in parallel on one end side of the inner bottom surface (one main surface 201 of the substrate portion 20) of the first recess 2A (see FIG. Only one is shown).

  One end side of the crystal resonator element 3 is conductively bonded and mounted on the crystal mounting pads 7a and 7b via the conductive adhesive 8. The crystal mounting pads 7a and 7b are connected to a pair of first wiring patterns 71a and 71b (piezoelectric vibration element connecting first wiring patterns), respectively, and extend to the central portion of the first recess.

  The pair of first wiring patterns 71 a and 71 b are formed at the end portions of the first wiring patterns 71 a and 71 b and penetrate a pair of columnar conductive vias 10 a and 10 b (perpendicular to the thickness direction of the substrate unit 20). Via the piezoelectric vibration element connecting conductive vias), they are connected to the second wiring patterns 11a and 11b (piezoelectric vibration element connecting wiring patterns) for mounting the IC formed in the second recess 2B described later. For this reason, it is connected in the shortest distance in the thickness direction of the substrate part 20, and the temperature of the IC 4 can be transmitted to the crystal resonator element 3 more accurately in a short time. In addition, since the conductive vias 10a and 10b (conductive vias for connecting piezoelectric vibration elements) do not constitute an intermediate wiring inside the substrate part 20, the heat distribution to the base 2 including the substrate part 20 and the heat between the wiring patterns are prevented. Can be suppressed. As a result, a temperature difference between the IC 4 and the crystal resonator element 3 can be hardly generated.

  As shown in FIG. 6 (a), the piezoelectric vibration element connecting conductive vias 10a and 10b are formed in a columnar shape having a flat surface and a bottom surface with a circular area x1, and a side surface height h1. In addition, the piezoelectric vibration element connecting conductive vias 10a and 10b are exposed only in the planes 10a1 and 10b1 of the piezoelectric vibration element connecting conductive vias in the first recess 2A, and the piezoelectric vibration element connecting conductive vias in the second recess 2B. Only the bottom surfaces 10a2 and 10b2 are exposed.

  In this embodiment, the crystal mounting pads 7a and 7b are connected to the pair of first wiring patterns 72a and 72b, respectively, and extend to the two notches 20c1 and 20c2 in the four corners of the outer peripheral edge of the substrate portion 20. Has been. Crystal vibration element external connection terminals 9a and 9b (piezoelectric vibration element external connection terminals) are formed on the surfaces of the notches 20c1 and 20c2.

  The crystal resonator element external connection terminals 9a and 9b are connected to the first wiring patterns 72a and 72b, respectively, so that they are connected only to the excitation electrode of the crystal resonator element, and the electrical characteristics of only the crystal resonator element are measured. It can be done. As a more preferable form in this embodiment, the crystal frame element external connection terminals 9a and 9b are adjacent to the first frame cutout portions 21c1 and 21c2 and the second frame cutout portions 22c1 and 22c2. Connection terminals (electrodes) are not formed, and external connection terminals (electrodes) are formed only in the notches 20c1 and 20c2 of the substrate portion. For this reason, an external connection terminal for a crystal resonator element that can measure only the characteristics of the crystal resonator element 3 that does not electrically interfere with the external circuit board or the lid 5 can be formed on the outer surface of the base 2. Further, by providing the crystal resonator element external connection terminal at the notch of the base plate located at the center of the side surface of the base at the corner of the base, it is possible to easily contact the terminals of the inspection probe and the measuring jig.

  External connection terminals 9c, 9d, 9e, and 9f are formed at the four corners of the upper surface of the second frame portion 22 of the base 2 (the bottom surface of the base 2) and are joined to mounting pads of an external circuit board (not shown) by solder. Yes. As a more preferable form in this embodiment, these four corner external connection terminals 9 c, 9 d, 9 e, 9 f are formed in a substantially L shape, and the substantially L shape is the four corners of the inner peripheral edge of the second frame portion 22. Has a curved portion and extends along each side of the inner peripheral edge of the second frame portion 22. Since the number of external connection terminals is formed according to the function of the oscillator, four or more configurations may be employed according to the additional function of the oscillator.

  Further, at the four corners of the inner peripheral edge of the second frame portion 22, columnar conductive vias 10 c and 10 d extending along the height direction of the inner peripheral wall of the second frame portion 22 (through the second frame portion 22). , 10e, 10f (conductive vias for connecting external connection terminals) are embedded. That is, the thickness direction of the second frame portion 22 is connected by columnar conductive vias 10c, 10d, 10e, and 10f (conductive vias for connecting external connection terminals) penetrating perpendicularly to the thickness direction of the second frame portion 22. Can be connected at the shortest distance. In addition, since the conductive vias 10c, 10d, 10e, and 10f (conducting vias for connecting external connection terminals) do not constitute an intermediate wiring inside the second frame portion 22, heat from the base 2 including the second frame portion 22 can be transmitted. Dispersion and heat distribution among the wiring patterns can be suppressed.

  As shown in FIG. 6 (b), the conductive vias 10c, 10d, 10e, and 10f for connecting the external connection terminals are formed by connecting the large arc 101 and the small arc 102 in the plan view shape (plane and bottom surface) of each conductive via. It has a crescent shape, and is formed in a columnar shape in which the flat surface and the bottom surface have an area x2 and the side surface height is h2. The columnar external connection terminal connecting conductive vias 10c, 10d, 10e, and 10f are in contact with the bottom arcs 10c2, 10d2, 10e2, and 10f2 of the external connection terminal connecting conductive vias in the second recess 2B. The side surfaces 10c3, 10d3, 10e3, and 10f3 are configured to be exposed. That is, as shown in FIGS. 3 and 4, the side surfaces of the small arcs 102 of the conductive vias 10 c, 10 d, 10 e, and 10 f are arranged at the four corners of the inner peripheral wall of the second frame portion 22.

  In this embodiment, the piezoelectric vibration element connecting conductive vias 10a and 10b are configured such that only the bottom surfaces 10a2 and 10b2 of the piezoelectric vibration element connecting conductive vias are exposed in the second recess 2B. 10d, 10e, and 10f are configured such that the bottom surfaces 10c2, 10d2, 10e2, and 10f2 of the external connection terminal connecting conductive vias and the side surfaces 10c3, 10d3, 10e3, and 10f3 in contact with the small arc 102 are exposed in the second recess 2B. doing. For this reason, it is possible to improve the heat dissipation of unnecessary heat transmitted from the external environment to the IC 4 via the external connection terminals 9c, 9d, 9e, and 9f without unnecessarily dissipating the heat transmitted from the IC 4 to the crystal resonator element 3. As a result, the heat transfer between the IC 4 and the crystal resonator element 3 can be improved, so that the temperature difference between the IC 4 and the crystal resonator element 3 can be made even more difficult.

  Each columnar conductive via is inscribed in the curved portions (four corners of the inner peripheral edge of the second frame portion 22) inside the four corners of the substantially L-shaped external connection terminals 9c, 9d, 9e, 9f. 10c, 10d, 10e, and 10f are formed and connected to each other. As a more preferable form in this embodiment, as shown in FIG. 3, each of the four corners inscribed in this portion and the curved portions inside the substantially corner-shaped external connection terminals 9c, 9d, 9e, 9f at the four corners. Intersections of line segments connecting the columnar conductive vias 10c, 10d, 10e, 10f, that is, the first line segment Q connecting the central part of the conductive via 10c and the central part of the conductive via 10e at the diagonal position, and the conductive via The external connection terminals and the conductive vias are arranged so that the intersection of the central portion of 10d and the second line segment R connecting the central portion of the conductive via 10f at the diagonal position coincides with the center of gravity O of the base. Are formed with respect to the base 2.

  A space surrounded by the inner peripheral edge 221 of the second frame portion 22 of the base 2 and the other main surface 202 of the substrate portion is a second recess 2B. The second recess 2 </ b> B is square in plan view and has the same shape as the inner peripheral edge 221 of the second frame portion 22. The second recess 2B has a smaller size in plan view than the first recess 2A, and the second recess 2B is in a positional relationship enclosed in the first recess 2A in plan view transmission.

  IC mounting second wiring patterns 11a, 11b, 11c, 11d, 11e, and 11f (wiring) are mounted on the inner bottom surface (the lower surface of the substrate portion 20) of the second recess 2B and mounted with a rectangular IC4 in plan view. Pattern) is formed. That is, as shown in FIGS. 2 and 3, the second wiring patterns 11c, 11a, and 11f are formed from the left side along the upper long side toward the inner bottom surface of the second recess 2B. Second wiring patterns 11d, 11b, and 11e are formed from the left side along the lower long side toward the bottom surface. Since the number of the second wiring patterns is formed according to the electrode pad of the IC 4, the number of the second wiring patterns may be six or more according to the additional function of the IC 4.

  In this embodiment, the second wiring patterns 11a, 11b, 11c, 11d, 11e, and 11f (wiring patterns) for mounting the IC are the first wiring patterns 71a and 71b formed in the conductive vias 10a and 10b and the first recess 2A. The piezoelectric vibration element connection second wiring patterns 11a and 11b (piezoelectric vibration element connection wiring patterns) connected to the crystal vibration element 3 and the external connection connected to the external connection terminals 9c, 9d, 9e, and 9f. Terminal connection second wiring patterns 11c, 11d, 11e, and 11f (external connection terminal connection wiring patterns) are formed. The area of each of the second wiring patterns 11a, 11b for connecting the piezoelectric vibration elements is made smaller than the area of each of the second wiring patterns 11c, 11d, 11e, 11f for connecting the external connection terminals. Yes. For example, in this embodiment, as shown in FIG. 3, the piezoelectric vibration element connecting second wiring pattern 11 a and the piezoelectric vibration element connecting second wiring pattern 11 b are substantially the same on the upper surface of the other main surface 202 of the substrate unit 20. The external connection terminal connection second wiring pattern 11c, the external connection terminal connection second wiring pattern 11d, the external connection terminal connection second wiring pattern 11e, and the external connection terminal connection second wiring pattern 11f. Are configured with substantially the same area, and the area of each of the second wiring patterns 11a, 11b for connecting a piezoelectric vibration element is the same as the area of each of the second wiring patterns 11c, 11d, 11e, 11f for connecting each external connection terminal. About 70 to 90%.

  The second wiring patterns 11c, 11d, 11e, and 11f (wiring patterns for connecting external connection terminals) are formed at the four corners of the inner bottom surface of the second recess 2B where the above-described columnar conductive vias 10c, 10d, 10e, and 10f are present. Is extended in the direction.

  The second wiring patterns 11c, 11d, 11e, and 11f are electrically connected to the external connection terminals 9c, 9d, 9e, and 9f via the columnar conductive vias 10c, 10d, 10e, and 10f, respectively. ing. In this embodiment, as a more preferable embodiment, as shown in FIG. 4, a dimension W1 along the inner peripheral edge 221 of the second frame portion 22 among the side surfaces of the conductive vias 10c, 10d, 10e, 10f (small arc on the bottom surface of the conductive via). 102) of the second wiring patterns 11c, 11d, 11e, and 11f in contact with the side surfaces of the conductive vias, the dimension W2 along the inner peripheral edge 221 of the second frame portion 22 (each second wiring). The pattern and the length of the portion in contact with the inner peripheral edge of the second frame portion) are formed larger. Therefore, it is possible to weaken the flow of solder from the conductive vias 10c, 10d, 10e, and 10f to the second wiring patterns 11c, 11d, 11e, and 11f, so that there is no need for bonding the IC 4 to the external circuit board. Inflow of solder can be prevented. In addition, on the second wiring patterns 11a, 11b, 11c, 11d, 11e, and 11f (wiring patterns) for mounting the IC, the electrode pads of the IC 4 are conductively bonded via the metal bumps 12 made of gold or the like.

  In this embodiment, as a more preferable embodiment, the sealing portion 6, the crystal mounting pads 7a and 7b, the first wiring patterns 71a, 71b, 72a and 72b, the second wiring patterns 11a, 11b, 11c, 11d, 11e and 11f, the conductive For vias 10a, 10b, 10c, 10d, 10e, and 10f and external connection terminals 9a, 9b, 9c, 9d, 9e, and 9f, tungsten (Young's modulus is higher than Young's modulus) than ceramic materials (Young's modulus is about 300 GPa). About 411 GPa) or molybdenum (Young's modulus is about 329 GPa). On these outer surfaces, a plating layer is laminated in the order of a nickel plating layer and a gold plating layer. The nickel plating layer and the gold plating layer are formed by electrolytic plating, and these are formed simultaneously. For this reason, even if the width of the second frame portion 22 is reduced due to the reduction in size, the hardness of the four corners of the second frame portion 22 due to the presence of the columnar conductive vias 10c, 10d, 10e, and 10f at the four corners. The strength of the base as a whole can be increased.

  The base 2 used in the embodiment of the present invention has a package structure with a substantially H-shaped cross section as described above. According to such an H-type package structure, since the crystal resonator element 3 and the IC 4 are accommodated in different spaces, it is less susceptible to the influence of gas generated during the manufacturing process and noise generated from other elements. There is an advantage that you can.

  In FIG. 1, a crystal resonator element 3 is a piezoelectric resonator element having a rectangular shape in plan view, in which various electrodes are formed on the front and back main surfaces of an AT-cut crystal resonator plate. In FIG. 1, illustration of various electrodes is omitted. Although not shown in FIG. 1, a pair of excitation electrodes are formed at a substantially central portion of the crystal diaphragm so that the excitation electrodes face each other. An extraction electrode is extended from each of the pair of excitation electrodes toward one short side edge of the front and back main surfaces of the crystal diaphragm. The terminal portion of the lead electrode is an adhesive electrode, and is joined to the above-described crystal mounting pads 7a and 7b via the conductive adhesive 8. In this embodiment, a silicone-based adhesive is used for the conductive adhesive 8, but a conductive adhesive other than a silicone-based adhesive may be used, or another conductive bonding material such as a metal bump may be used. Good.

  The IC 4 used in the present embodiment is a one-chip integrated circuit element incorporating an inverter amplifier (oscillation amplifier) such as a CMOS, and is an oscillation that is connected to the crystal resonator element 3 and amplifies the frequency signal of the crystal resonator element 3. In order to perform temperature compensation so that the frequency fluctuation becomes smaller than the frequency temperature characteristics of the crystal resonator element based on the temperature information of the circuit unit, the temperature detector that detects the temperature change with the ambient temperature, and the temperature information of the temperature detector And a region constituting the temperature compensation circuit portion. In this embodiment, a so-called TCXO IC having a temperature compensation function or the like is used, but a so-called VCTCXO IC having a frequency adjustment circuit added as an additional function or an OCTCXO IC having a heater function added. Or an IC having additional functions other than these, or an IC in which these are combined. Further, the IC 4 may be bipolar other than CMOS, bi-CMOS, or the like.

  In FIG. 1, the lid 5 is a flat plate having a substantially rectangular shape in plan view. The cover 5 is made of Kovar as a base material, and the surface of the base material is plated with nickel plating and gold-tin brazing material. The above is the outline of each component.

  In each of the above components, the crystal resonator element 3 is electrically and mechanically connected to the upper portions of the crystal mounting pads 7a and 7b formed on the inner bottom surface of the first recess 2A of the base 2 via the conductive adhesive 8. Mounted. Then, the quartz resonator element is stored in the first recess 2A after the frequency of the crystal diaphragm is adjusted to a desired value while bringing the inspection probe into contact with the crystal resonator element external connection terminals 9a and 9b of the base 2. In this state, the base sealing portion 6 is covered with a metal lid 5, and the sealing material of the metal lid 4 and the base joint portion 6 are melt-cured to perform hermetic sealing. Then, the second wiring patterns 11a, 11b, 11c, 11d, 11e, and 11f formed on the inner bottom surface of the second concave portion 2B of the base 2 are electrically and mechanically connected to the IC 4 via the metal bumps 12, and the IC 4 Is mounted on the inner bottom surface of the second recess 2B. Then, necessary adjustments are made and the surface-mounted crystal oscillator 1 is completed.

  The surface-mounted crystal oscillator 1 configured as described above is mounted on a mounting pad of an external circuit board (not shown) and is electrically and mechanically connected by solder. At this time, between the substantially L-shaped external connection terminals 9c, 9d, 9e, and 9f at the four corners of the bottom surface of the surface-mount type crystal oscillator 1 and a mounting pad of an external circuit board (not shown), a paste-like solder is provided. It is mounted in a state of being interposed. In this state, it is carried into a heating and melting furnace, and the solder is heated and melted to heat and melt the external circuit board mounting pad (not shown) and the substantially L-shaped external connection terminals 9c at the four corners of the bottom surface of the surface-mounted crystal oscillator 1. 9d, 9e, 9f and the columnar conductive vias 10c, 10d, 10e, 10f are joined.

  According to the surface-mounted crystal oscillator 1 according to the embodiment of the present invention, each piezoelectric vibration element connecting second wiring pattern 11a is determined from the area of each of the external connection terminal connecting second wiring patterns 11c, 11d, 11e, and 11f. , 11b is configured to be smaller. For this reason, without dissipating heat from the IC 4, it is transmitted to the conductive vias 10 a and 10 b (piezoelectric vibration element connecting conductive vias), and the first wiring pattern 71 a is transmitted from the conductive vias 10 a and 10 b (piezoelectric vibration element connecting conductive vias). , 71b (piezoelectric vibration element connecting first wiring pattern) can be quickly transmitted to the crystal vibration element 3. As a result, a temperature difference between the IC 4 and the crystal resonator element 3 can be hardly generated. In addition, adverse effects due to stray capacitance on the crystal resonator element 3 can be reduced more effectively.

  The area of each of the external connection terminal connection second wiring patterns 11c, 11d, 11e, and 11f is configured to be larger than the area of each of the piezoelectric vibration element connection second wiring patterns 11a and 11b. For this reason, part of the heat generated in the IC 4 is dissipated to the external connection terminal connecting second wiring patterns 11c, 11d, 11e, and 11f, and only the temperature of the IC 4 is unilaterally increased with respect to the crystal resonator element 3. Can be suppressed. Moreover, since the junction area | region with IC4 can be ensured by the 2nd wiring pattern 11c, 11d, 11e, 11f for external connection terminal connection, the reliability of connection with IC4 and a wiring pattern can be improved. The reliability of the connection between the IC 4 and the wiring pattern can be improved.

  Further, on the second wiring patterns 11a, 11b, 11c, 11d, 11e, and 11f (wiring patterns) for mounting the IC, the electrode pads of the IC 4 are conductively bonded via metal bumps 12 made of gold or the like. As a result, the heat transfer between the IC 4 and the crystal resonator element 3 can be improved, so that the temperature difference between the IC 4 and the crystal resonator element 3 can be made even less likely to occur.

  As described above, in the embodiment of the present invention, in the piezoelectric oscillator in which the crystal resonator element 3 and the IC 4 having the temperature detection unit are accommodated in different spaces, the temperature difference between the elements in the different spaces is eliminated and the temperature condition is accompanied. A piezoelectric oscillator with improved electrical property stability can be provided. More specifically, since the temperature environment of the crystal resonator element 3 and the temperature environment of the IC 4 are under the same conditions, more accurate temperature compensation can be performed. Therefore, a temperature-compensated crystal with higher performance with higher frequency stability. An oscillator can be provided.

  In addition, even when the surface mount type crystal oscillator 1 is reduced in size and the area of the external connection terminals 9c, 9d, 9e, and 9f is restricted, the conductive vias 10c, 10d, 10e, and 10f are bonded to the external circuit board. The solder application area can be enlarged. Therefore, not only a planar solder joint by the external connection terminals 9c, 9d, 9e, 9f but also a three-dimensional solder joint by forming a solder fillet along the conductive vias 10c, 10d, 10e, 10f. Is obtained.

  Moreover, since this solder fillet is formed along the conductive vias 10c, 10d, 10e, and 10f at the four corners, the solder fillet acts in a balanced manner in the direction of the center of gravity O of the surface-mounted crystal oscillator 1. The anchor action by the solder fillet formed by the conductive vias 10c, 10d, 10e, and 10f can be further enhanced. As a result, it is possible to increase the solder joint strength with the external circuit board while adapting to the miniaturization of the surface-mounted crystal oscillator 1.

  Even if the amount of paste-like solder applied to the external connection terminals 9c, 9d, 9e, and 9f at the four corners varies, the conductive vias 10c, 10d, and 10e are connected to the external connection terminals 9c, 9d, 9e, and 9f. , 10f, the solder coating can be adjusted, so that the amount of solder applied to the external connection terminals 9c, 9d, 9e, 9f at the four corners is made uniform, and the surface mount crystal oscillator 1 is mounted on the external circuit board. Thus, when the solder is melted and bonded, it is possible to suppress the surface-mounted crystal oscillator 1 from being mounted tilted from the external circuit board or rotated.

  In particular, even if the area of the external connection terminals 9c, 9d, 9e, and 9f is restricted due to the miniaturization of the surface-mounted crystal oscillator 1, the area of the external connection terminals is ensured by making it substantially L-shaped. It is possible to prevent the strength of the joint with the external circuit board from being lowered, and it is possible to cause the tension by the solder joint to be generated in a well-balanced state in the state along each side of the second frame portion 22. . Further, the solder flow from the external connection terminals 9c, 9d, 9e, 9f to the conductive vias 10c, 10d, 10e, 10f is promoted.

  In addition, the solder fillet is symmetrical with respect to the center line AA that passes through the center of gravity O of the base and is parallel to the long side of the second frame and the center line BB that is parallel to the short side of the second frame. Since the four corner anchor portions are configured, the surface mounting type crystal oscillator 1 can be made to act so that the tension due to the solder joint is uniformly generated toward the center of gravity O of the surface mount type crystal oscillator 1. As a result, the solder joint strength with the external circuit board can be further increased, and the surface-mounted crystal oscillator 1 can be further restrained from being tilted and rotated from the external circuit board. it can.

  In the above-described embodiment of the present invention, a base having a substantially H-shaped cross section in which frame portions are formed on both the main surface side (upper side) and the other main surface side (lower side) of the substrate portion is described as an example. However, a cap-shaped lid having a concave portion on the lower side is used with a base having a frame portion formed only on the other main surface side (lower side) without forming a frame portion on one main surface side (upper side) of the substrate portion. It is good also as the structure used.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  It can be applied to mass production of piezoelectric vibration devices.

1 Crystal oscillator (piezoelectric oscillator)
2 Base 2A 1st recessed part 2B 2nd recessed part 20 Substrate part 20c, 20c1, 20c2, 20c3, 20c4 Notch part 200 Outer peripheral part 201 One main surface 202 Other main surface 21 First frame part 21c, 21c1, 21c2, 21c3, 21c4 Notch part 210 Outer part 211 Inner part 22 Second frame part 22c, 22c1, 22c2, 22c3, 22c4 Notch part 220 Outer part 221 Inner part 3 Crystal vibration element (piezoelectric vibration element)
4 IC
5 Lid 6 Sealing part 7a, 7b Crystal mounting pad 71a, 71b, 72a, 72b First wiring pattern 8 Conductive adhesive 9a, 9b External connection terminal for crystal vibration element (external connection terminal for piezoelectric vibration element)
9c, 9d, 9e, 9f External connection terminal 10a, 10b, 10c, 10d, 10e, 10f Conductive via 10a1, 10b1 Plane of conductive via 10a2, 10b2, 10c2, 10d2, 10e2, 10f2 Bottom of conductive via 10c3, 10d3, 10e3 , 10f3 Side surface of conductive via 101 Large arc in plan view shape of conductive via 102 Small arc in plan view shape of conductive via 11a, 11b, 11c, 11d, 11e, 11f Second wiring pattern for mounting IC 12 Metal bump

Claims (2)

A substrate part whose upper side is one main surface and whose lower side is the other main surface;
A first frame portion extending upward from an outer peripheral portion of one main surface of the substrate portion;
A second frame portion extending downward from the outer peripheral portion of the other main surface of the substrate portion;
An external connection terminal formed on the second frame portion;
A base with
A piezoelectric vibration element mounted in a first recess surrounded by the first frame portion and one main surface of the substrate portion ;
An IC having a temperature detection portion mounted in a second recess surrounded by the second frame portion and the other main surface of the substrate portion;
A lid for hermetically sealing the piezoelectric vibration element;
In the piezoelectric oscillator consisting of
A plurality of wiring patterns for electrically and mechanically joining the IC are formed on the inner bottom surface of the second recess,
The plurality of wiring patterns are formed with a plurality of piezoelectric vibration element connection wiring patterns to be connected to the piezoelectric vibration elements and a plurality of external connection terminal connection wiring patterns to be connected to the external connection terminals.
A plurality of piezoelectric vibration element connecting first wiring patterns for electrically and mechanically joining the piezoelectric vibration elements are formed on the inner bottom surface of the first recess ,
Of the first wiring pattern for connecting piezoelectric vibration elements, the extended end portion of the central portion of the inner bottom surface of the first recess and the wiring pattern for connecting piezoelectric vibration elements on the inner bottom surface of the second recess are the thickness of the substrate portion. Is connected by a conductive via for connecting a piezoelectric vibration element penetrating in the direction,
Between each of the external connection terminal connection wiring patterns, each piezoelectric vibration element connection wiring pattern is formed,
The piezoelectric oscillator, wherein an area of each of the piezoelectric vibration element connecting wiring patterns is smaller than an area of each of the external connecting terminal connecting wiring patterns. The piezoelectric oscillator according to claim 1,
The piezoelectric oscillator, wherein the IC and the wiring pattern are joined electrically and mechanically through metal bumps.

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