JP2011055145A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device that prevents an oscillating frequency from fluctuating. <P>SOLUTION: An electronic device includes: a device-equipped member having a first concave part and a second concave part, in which one copper plate connection terminal for heat transmission and three external connection terminals are provided on a side of the second concave part; a piezoelectric vibrating device that is housed in the first concave part and has an excitation electrode on both main surfaces of a piezoelectric element plate; an integrated circuit device that is housed in the second concave part and provided with at least an oscillating circuit; a lid member for sealing the first concave part; and a copper plate for heat transmission that is bonded to a side of the second concave part of the device-equipped member. One surface of the copper plate for heat transmission, a circuit-forming surface of the integrated circuit device and its opposite side surface are connected via an electrically-conductive adhesive, and the copper plate for heat transmission is connected with the copper plate connection terminal for heat transmission. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic device used for an electronic device or the like.

Conventionally, various electronic devices have been used in electronic devices such as portable communication devices.
Among these electronic devices, for example, a piezoelectric oscillator will be described.
As shown in FIG. 4, a piezoelectric oscillator 200 that is a conventional electronic device includes a piezoelectric vibration element 220 in a first recess K1 of an element mounting member 210 having a first recess K1 and a second recess K2. A structure that is mounted and hermetically sealed with a lid member 214, and an integrated circuit element 230 including a circuit for performing temperature compensation of, for example, an oscillation circuit or a piezoelectric vibration element 220 is accommodated in the second recess K2. It has become. The piezoelectric oscillator 200 is an electronic device, and a circuit forming surface of an integrated circuit element 230 connected to the substrate portion 211 via the bumps 231 is formed on the other main surface of the substrate portion 211 of the second recess K2. In order to protect, a resin 240 is filled between the substrate portion 211 and the integrated circuit element 230.

  In the conventional piezoelectric oscillator 200 described above, the piezoelectric vibration element 220 is mounted on one main surface of the substrate portion 211 of the element mounting member 210, and the integrated circuit element 230 is mounted on the other main surface of the substrate portion 211. Therefore, a small electronic device having a small surface area can be realized. Further, since the conventional piezoelectric oscillator 200 has the piezoelectric vibration element 220 mounted on one main surface of the substrate portion 211 and then the integrated circuit element 230 mounted on the other main surface of the substrate portion 211, the piezoelectric vibration element The heat treatment performed to stabilize the frequency of 220 is not applied to the integrated circuit element 230, and the operation reliability and connection reliability of the integrated circuit element 230 can be improved. In addition, the integrated circuit element 230 connected to the substrate portion 211 of the second recess K2 of the piezoelectric oscillator 200 generates heat by the starting voltage when starting the oscillation circuit of the integrated circuit element 230 or the like. Will do. At that time, the piezoelectric oscillator 200 is mounted on an external mounting substrate, and the second recess K2 in which the integrated circuit element 230 is mounted is a closed space when mounted on the external mounting substrate. . As a result, heat from the integrated circuit element 230 is stored in the space closed by the mounting substrate and the second recess K2 (see, for example, Patent Document 1).

JP 2007-123489 A (6th page, FIG. 1)

  However, in the conventional piezoelectric oscillator 200, when the piezoelectric oscillator is mounted on an external mounting substrate as described above, the second concave portion K2 in which the integrated circuit element is mounted becomes a closed space. The heat generated by the circuit element 230 is trapped in the space in the second recess K2 and the temperature sensed by the temperature sensing element of the integrated circuit element rises, and the piezoelectric vibration accommodated in the first recess K1 of the piezoelectric oscillator 200 is increased. There is a problem that a temperature difference occurs between the temperature sensed by the element 220 and the temperature sensed by the integrated circuit element 230 accommodated in the second recess K2, and the oscillation frequency of the piezoelectric oscillator 200 varies. Further, due to manufacturing variations when manufacturing the piezoelectric oscillator 200, the integrated circuit device 230 may not contact an external mounting substrate due to variations in bump height of the bump 231 connecting the integrated circuit device 230 to the substrate portion 211. In some cases, heat conduction due to heat generation from the integrated circuit element 230 becomes insufficient.

  Accordingly, the piezoelectric oscillator of the present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic device in which the oscillation frequency of the piezoelectric oscillator does not fluctuate due to heat generated by the integrated circuit element.

  The electronic device of the present invention has a first recess and a second recess, an element mounting member including one heat transfer copper plate connection terminal and three external connection terminals on the second recess side, A piezoelectric vibration element housed in one recess and having excitation electrodes on both principal surfaces of the piezoelectric element plate, an integrated circuit element housed in the second recess and having at least an oscillation circuit, and the first recess A lid member for sealing and a copper plate for heat transfer bonded to the second recess side of the element mounting member, opposite to one surface of the copper plate for heat transfer and the circuit forming surface of the integrated circuit element The heat transfer copper plate is connected to the heat transfer copper plate connection terminal. The heat transfer copper plate is connected to the side surface via a conductive adhesive.

  In the electronic device according to the present invention, the heat transfer copper plate connection terminal at one of the four corners of the second frame portion to which the heat transfer copper plate is connected functions as a ground terminal. It is a feature.

  In the electronic device of the present invention, the integrated circuit element is mounted by connecting one surface of the heat transfer copper plate and the surface opposite to the circuit forming surface of the integrated circuit element through a conductive adhesive. The heat trapped in the second recess is surely conducted to the heat transfer copper plate. Since the heat transfer copper plate is connected to an external mounting board via the heat transfer copper plate connection terminal that functions as a ground terminal, the heat generated from the integrated circuit element spreads to the heat transfer copper plate, and from the heat transfer copper plate to the outside Heat is transferred to the mounting board. In the electronic device of the present invention, the wiring pattern of the mounting substrate connected to the heat transfer copper plate is exposed, and heat is radiated therefrom. As a result, the electronic device of the present invention can suppress a temperature rise due to heat generation from the integrated circuit element, and the temperature sensed by the piezoelectric vibration element accommodated in the first recess and the second recess are accommodated. Since the temperature difference from the temperature sensed by the integrated circuit element can be reduced, fluctuations in the oscillation frequency of the piezoelectric oscillator can be prevented.

  In addition, the electronic device of the present invention is connected to an external mounting board because one heat transfer copper plate connection terminal at each of the four corners of the second frame portion to which the heat transfer copper plate is connected functions as a ground terminal. In this case, the ground terminal is connected to the external ground electrode, so that the heat radiation area can be increased and the heat radiation effect can be improved.

It is sectional drawing which showed an example of the electronic device which concerns on embodiment of this invention. It is the conceptual diagram which showed the 2nd recessed part side of the element mounting member of the state which connected the element mounting member of FIG. 1 and the copper plate for heat transfer. It is sectional drawing which shows the joining method of the copper plate for heat transfer of this invention. It is sectional drawing which showed the conventional electronic device.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the same component and the overlapping description is abbreviate | omitted. The electronic device will be described as a piezoelectric oscillator. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an example of an electronic device according to an embodiment of the present invention.
As shown in FIG. 1, a piezoelectric oscillator 100 that is an electronic device mainly includes an element mounting member 10, a lid member 14, a piezoelectric vibration element 20, an integrated circuit element 30, and a heat transfer copper plate 40.

As shown in FIG. 1, the element mounting member 10 has a first recess K1 and a second recess K2, and one copper plate connection terminal 15 for heat transfer and three external connection terminals on the second recess K2 side. 46, and includes a substrate part 11, a first frame part 12, and a second frame part 13.
The substrate part 11 has a structure sandwiched between the first frame part 12 and the second frame part 13.

  The first frame portion 12 is joined to the substrate portion 11 to form a first recess K1. The second frame portion 13 is joined to the substrate portion 11 to form a second recess K2. In the piezoelectric oscillator 100 according to the present invention, the integrated circuit element 30 is accommodated in the second recess K2 facing the heat transfer copper plate 40 side out of the first recess K1 and the second recess K2, and the other first recess. The piezoelectric vibration element 20 is accommodated in K1. Here, the piezoelectric vibration element 20 and the integrated circuit element 30 are connected by an inner layer wiring (not shown) provided inside the substrate portion 11.

  Moreover, the board | substrate part 11, the 1st frame part 12, and the 2nd frame part 13 which comprise the element mounting member 10 consist of ceramic materials, such as glass-ceramics and an alumina ceramic, for example. Also, one heat transfer copper plate connection terminal 15 at the four corners of the second frame portion 13 and one of the four corners of one main surface of the heat transfer copper plate 40 are electrically and mechanically joined, and It is fixed.

  Further, the second frame portion 13 forming the second recess K2 in which the integrated circuit element 30 is accommodated has one heat transfer copper plate connection terminal 15 joined to the heat transfer copper plate 40 at the four corners thereof. Three external connection terminals 46 to be joined to the external mounting substrate are provided. In addition, one heat transfer copper plate connection terminal 15 at the four corners of the second frame portion 13 connected to the heat transfer copper plate 40 functions as a ground terminal. Further, the three external connection terminals 46 at the four corners of the second frame portion 13 function as a VCC terminal, a VCON terminal, and an OUT terminal, respectively. In addition, one of the four corners of the other main surface of the heat transfer copper plate 40 joined to the heat transfer copper plate connection terminal 15 is connected to an external ground electrode when connected to an external mounting board.

  The lid member 14 has a structure that hermetically seals the first recess K1 in which the piezoelectric vibration element 20 is accommodated. The lid member 14 is made of 42 alloy, Kovar, phosphor bronze, or the like.

  The piezoelectric vibration element 20 is housed in the first recess K1 and has a structure including excitation electrodes (not shown) on both main surfaces of the piezoelectric element plate. The piezoelectric vibration element 20 accommodated in the first recess K1 of the element mounting member 10 is formed by attaching and forming a pair of excitation electrodes on both main surfaces of a piezoelectric element plate cut along a predetermined crystal axis. When an alternating voltage from the outside is applied to the piezoelectric element plate via a pair of excitation electrodes, thickness shear vibration is caused at a predetermined frequency. As the piezoelectric element plate, for example, quartz is used.

  The integrated circuit element 30 is accommodated in the second recess K2 and has at least an oscillation circuit. Further, the integrated circuit element 30 is bonded to a mounting pattern provided on the other main surface of the substrate portion 11 by being mounted via bumps 31. Here, a circuit is formed on the surface of the integrated circuit element 30 facing the substrate portion 11 side. A resin 50 is filled between the substrate unit 11 and the integrated circuit element 30. Further, the integrated circuit element 30 has temperature compensation data for compensating the temperature characteristics of the temperature sensing element and the piezoelectric vibration element 20 for detecting the ambient temperature state on the surface on which the circuit is formed, and based on the temperature compensation data. A temperature compensation circuit that corrects the vibration characteristics of the piezoelectric vibration element 20 according to a temperature change, an oscillation circuit that is connected to the temperature compensation circuit and generates a predetermined oscillation output, and the like are provided. The oscillation generated by the oscillation circuit The output is used as a reference signal such as a clock signal after being output to the outside.

  In addition, the heat transfer copper plate 40 is provided with a conductive adhesive on the surface opposite to the circuit forming surface of the integrated circuit element 30 and one heat transfer copper plate connection terminal 15 at the four corners of the second frame portion 13. 42 is joined. Below, the joining method of the copper plate 40 for heat transfer of the piezoelectric oscillator of this invention is demonstrated. As shown in FIG. 3, first, the second concave portion K <b> 2 in which the integrated circuit element 30 is accommodated is in a state of facing upward. Next, the conductive adhesive 42 is applied to the surface of the integrated circuit element 30 opposite to the circuit formation surface and one heat transfer copper plate connection terminal 15 at the four corners of the second frame portion 13. Thereafter, the heat transfer copper plate 40 is placed on the surface opposite to the circuit formation surface of the integrated circuit element 30 and one heat transfer copper plate connection terminal 15 at the four corners of the second frame portion 13. Heat cure in an oven. By this heat curing, the surface opposite to the circuit forming surface of the integrated circuit element 30 and one heat transfer copper plate connection terminal 15 at the four corners of the second frame portion 13 are simultaneously bonded to the heat transfer copper plate 40. Is done. As described above, the heat transfer copper plate 40 is connected to the surface opposite to the circuit formation surface of the integrated circuit element 30 via the conductive adhesive 42, and one of the four corners of the second frame portion 13 is connected. The heat transfer copper plate connection terminal 15 is connected to the conductive adhesive 42. In addition, as a material of the heat transfer copper plate 40, for example, a copper plate having a thickness of about 0.1 mm is used.

  As described above, in the piezoelectric oscillator 100 of the present invention, one surface of the heat transfer copper plate 40 and the surface opposite to the circuit forming surface of the integrated circuit element 30 are connected via the conductive adhesive 42. Thus, the heat transfer copper plate 40 functions as a heat transfer plate to an external mounting substrate, and an increase in temperature sensed by the temperature sensitive element of the integrated circuit element 30 due to heat generation of the integrated circuit element 30 can be suppressed. As a result, in the piezoelectric oscillator 100 of the present invention, fluctuations in the oscillation frequency of the piezoelectric oscillator 100 can be prevented. That is, the heat trapped in the second recess K2 in which the integrated circuit element 30 is mounted is reliably conducted to the heat transfer copper plate 40. The heat conducted to the heat transfer copper plate 40 is connected to an external mounting board via the heat transfer copper plate connection terminal 15 functioning as a ground terminal, and therefore the wiring pattern of the external mounting board from the heat transfer copper plate 40. Heat is transferred to. In addition, since the wiring pattern of the external mounting board is exposed, it is thermally cooled by the outside air and radiated to the outside.

  In addition, the piezoelectric oscillator 100 of the present invention is configured so that the heat transfer copper plate 40 connected to the surface opposite to the circuit formation surface of the integrated circuit element 30 via the conductive adhesive 42 has four corners of the second frame portion 13. It is connected to one of the heat transfer copper plate connection terminals 15 and functions as a ground terminal. Thus, when the piezoelectric oscillator 100 is mounted on an external mounting board, the heat generated from the integrated circuit element 30 can be radiated to the ground electrode of the external mounting board via the heat transfer copper plate 40 serving as a ground terminal. Here, by increasing the area of the ground electrode of the external mounting substrate connected to the heat transfer copper plate 40 that becomes the ground terminal of the piezoelectric oscillator 100, the heat dissipation area can be increased and the heat dissipation effect can be enhanced.

  In addition to the above-described embodiments, various changes and improvements can be made without departing from the scope of the present invention. For example, the electronic device shown in the above embodiment is a piezoelectric element in which an excitation electrode or an extraction electrode is provided on the surface of a rectangular piezoelectric element plate as a piezoelectric vibration element 20 mounted inside the piezoelectric oscillator 100. Although the vibration element 20 is shown, the present invention is not limited to this. For example, the vibration element 20 may be a piezoelectric vibration element having a circular shape in plan view or a tuning fork-shaped piezoelectric base plate provided with various electrodes. A surface acoustic wave element may be used.

DESCRIPTION OF SYMBOLS 10 ... Element mounting member 11 ... Board | substrate part 12 ... 1st frame part 13 ... 2nd frame part 14 ... Cover member 15 ... Copper plate connection terminal 20 for heat transfer ... Piezoelectric vibration element 30 ... integrated circuit element 31 ... bump 40 ... heat transfer copper plate 42 ... conductive adhesive 46 ... external connection terminal 50 ... resin K1 ... first Recess K2 ... second recess

Claims (2)

An element mounting member having a first recess and a second recess, and comprising one heat transfer copper plate connection terminal and three external connection terminals on the second recess side;
A piezoelectric vibration element housed in the first recess, and provided with excitation electrodes on both principal surfaces of the piezoelectric element plate;
An integrated circuit element housed in the second recess and provided with at least an oscillation circuit;
A lid member for sealing the first recess;
A heat transfer copper plate joined to the second concave portion side of the element mounting member, and one surface of the heat transfer copper plate and a surface opposite to the circuit forming surface of the integrated circuit element are conductive. An electronic device connected through an adhesive, wherein the heat transfer copper plate is connected to the heat transfer copper plate connection terminal. 2. The electronic device according to claim 1, wherein the heat transfer copper plate connection terminal at one of the four corners of the second frame portion to which the heat transfer copper plate is connected functions as a ground terminal.

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