JP5689702B2 - Piezoelectric device - Google Patents

Description

  The present invention relates to a piezoelectric device used in electronic equipment and the like.

As a conventional piezoelectric device, for example, a structure mainly composed of an element mounting member, a piezoelectric vibration element, a thermistor element, and a lid is known (see, for example, Patent Document 1).
The element mounting member includes a substrate part, a first frame part, and a second frame part.
A second frame portion is provided on the main surface of the substrate portion to form a second recess space, and a first frame portion is provided to the second frame portion to form a first recess space.
Two pairs of piezoelectric vibration element mounting pads are provided on one main surface of the second frame exposed in the first recess space.
A thermistor element mounting pad is provided on one main surface of the substrate portion exposed in the second recess space.
Also, external connection electrode terminals are provided at the four corners of the other main surface of the substrate portion.
On the piezoelectric vibration element mounting pad, a piezoelectric vibration element having a pair of excitation electrodes electrically connected via a conductive adhesive on the front and back main surfaces is mounted. A metal lid is put on and joined to the top surface of the first frame portion of the element mounting member surrounding the piezoelectric vibration element. Thereby, the first recess space and the second recess space are hermetically sealed.
A thermistor element connected via a conductive bonding material such as solder is mounted on the thermistor element mounting pad.
The thermistor element outputs a resistance value to the outside of the piezoelectric device via the external connection electrode terminal. Since the voltage changes due to the change in the output resistance value, the temperature information can be obtained from the voltage at that time by converting the output resistance value into a voltage according to the relationship between the voltage and the temperature. For example, it can be converted into temperature information in a main IC such as an electronic device.
In addition, the external connection electrode terminal includes two pairs of crystal vibration element electrode terminals and two pairs of thermistor element electrode terminals. The crystal vibration element electrode terminals are arranged diagonally. Similarly, the thermistor element electrode terminals are also arranged diagonally.

JP 2008-205938 A

  However, in the conventional piezoelectric device, when a conductive bonding material such as solder for mounting the thermistor element on the thermistor element mounting pad of the element mounting member is applied to the thermistor element mounting pad, the space for the application needle to enter It is necessary to provide. Therefore, the exposure of the thermistor element wiring pattern drawn from the thermistor element mounting pad increases, and the conductive bonding material flows from the thermistor element mounting pad to the thermistor element wiring pattern, so that the thermistor element is detached from the thermistor element mounting pad. There was a problem such as.

  Further, the conventional piezoelectric device has a problem that when the thermistor element is mounted on the thermistor element mounting pad of the element mounting member, the thermistor element is displaced, and the thermistor element is detached from the thermistor element mounting pad.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a piezoelectric device capable of reducing the thermistor element from being detached from the thermistor element mounting pad when the thermistor element is bonded. .

The piezoelectric device of the present invention is an element mounting member comprising a substrate portion, a first frame portion provided on one main surface of the substrate portion, and a second frame portion provided on the other main surface of the substrate portion. A piezoelectric vibration element mounted on a piezoelectric vibration element mounting pad provided on a main surface of the substrate portion exposed in the first recess space formed by the substrate portion and the first frame portion, and the substrate portion A thermistor element mounted on the thermistor element mounting pad provided on the main surface of the substrate portion exposed in the second recessed space formed by the first frame portion and the second frame portion using a conductive bonding material, and the thermistor Two pairs of thermistor element wiring patterns connected to the mounting pad, a lid for hermetically sealing the first recess space, and the other main surface of the substrate portion of the second frame portion face the same direction. Two pairs of piezoelectric vibration element electrode terminals and two pairs of thermis at four corners of the surface A third recessed space provided between the external connection electrode terminal composed of the element electrode terminal and two external connection electrode terminals adjacent to each other on the same side of the second frame portion of the element mounting member. The two thermistor element wiring patterns exposed on the bottom surface in the second recess space are parallel to the outer peripheral edge of the long side of the element mounting member in the third recess space, Provided in a position which is line-symmetric with respect to the center line of the bottom surface in the recess space, and is parallel to the outer peripheral edge on the short side of the element mounting member on the main surface of the pair of thermistor element wiring patterns. As described above, bumps are provided.

According to the piezoelectric device of the present invention, the pair of thermistor element wiring patterns exposed on the bottom surface in the second recess space is parallel to the outer peripheral edge on the long side of the element mounting member in the third recess space. Thus, the outer peripheral edge portion on the short side of the element mounting member is provided on the main surface of the pair of thermistor element wiring patterns provided at a position that is line-symmetric with respect to the center line of the bottom surface in the second recess space. Since the bumps are provided so as to be parallel to the thermistor element, it is possible to reduce the flow of the conductive bonding material along the wiring pattern for the thermistor element after applying the conductive bonding material to the thermistor element mounting pad. It is possible to maintain a conductive bonding material sufficient to maintain the bonding strength. Therefore, it can reduce that a thermistor element remove | deviates from a thermistor element mounting pad.

  Further, the main surface of the two pairs of thermistor element wiring patterns is provided with bumps so as to be parallel to the element mounting member and the outer peripheral edge of the short side, so that the thermistor elements are arranged more than the bumps. Therefore, the thermistor element can be positioned.

1 is an exploded perspective view showing a piezoelectric device according to an embodiment of the present invention. It is AA sectional drawing of FIG. (A) It is the top view which looked at the piezoelectric device which concerns on embodiment of this invention from the thermistor element mounting state in the state before mounting a thermistor element, (b) The state after mounting the thermistor element on the piezoelectric device which concerns on embodiment of this invention It is the top view seen from the thermistor element mounting side. (A) is the top view seen from one main surface of the board | substrate part of the element mounting member which comprises the piezoelectric device which concerns on embodiment of this invention, (b) is the piezoelectric device which concerns on embodiment of this invention. It is the top view seen from one main surface of the inner layer of the element mounting member to comprise. (A) is the top view seen from the other main surface of the board | substrate part of the element mounting member which comprises the piezoelectric device which concerns on embodiment of this invention, (b) is a piezoelectric device which concerns on embodiment of this invention. It is the top view which looked at the element mounting member which comprises from the other main surface.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. A case where quartz is used for the piezoelectric vibration element will be described.

  As shown in FIGS. 1 and 2, the piezoelectric device 100 according to the embodiment of the present invention mainly includes an element mounting member 110, a piezoelectric vibration element 120, a lid body 130, and a thermistor element 140. In the piezoelectric device 100, the piezoelectric vibration element 120 is mounted in the first recessed space K1 formed in the element mounting member 110, and the thermistor element 140 is mounted in the second recessed space K2. . The first recess space K1 is hermetically sealed by the lid 130.

As shown in FIGS. 1 and 2, the piezoelectric vibration element 120 is formed by adhering an excitation electrode 122 to a crystal element plate 121, and an alternating voltage from the outside passes through the excitation electrode 122. When applied to 121, excitation occurs in a predetermined vibration mode and frequency.
The quartz base plate 121 is a substantially flat plate shape that is cut from an artificial crystalline lens at a predetermined cut angle and is subjected to outer shape processing, and has a planar shape of, for example, a quadrangle.
The excitation electrode 122 is formed by depositing and forming a metal in a predetermined pattern on both the front and back main surfaces of the crystal base plate 121.
Such a piezoelectric vibration element 120 includes a lead electrode 123 extending from the excitation electrode 122 attached to both main surfaces of the piezoelectric vibration element 120 and a piezoelectric vibration element mounting pad 111 formed on the inner bottom surface of the first recess space K1. Are electrically and mechanically connected via the conductive adhesive DS to be mounted in the first recess space K1. At this time, an end side that is a free end opposite to the side on which the extraction electrode 123 is provided is defined as a tip portion of the piezoelectric vibration element 120.

The thermistor element 140 shown in FIGS. 1 to 2 shows a remarkable change in electrical resistance due to a temperature change. Since the voltage changes due to the change in resistance value, the relationship between the resistance value and the voltage, and the voltage and temperature. Therefore, by converting the output resistance value into a voltage, temperature information can be obtained from the voltage obtained by the conversion. The thermistor element 140 outputs a resistance value output from a main IC (not shown) such as an electronic device by the resistance value being output to the outside of the piezoelectric device 100 via the external connection electrode terminal G. Temperature information can be obtained by converting the voltage.
As shown in FIG. 2, the thermistor element 140 includes a conductive bonding material HD such as solder on a thermistor element mounting pad 112 provided on a substrate part 110a (described later) exposed in the second recessed space K2 of the element mounting member 110. It is mounted through.
As shown in FIG. 3, the thermistor element 140 is mounted so as to be parallel to the long side wall portion of the second recess space K <b> 2 of the element mounting member 110. That is, the thermistor element 140 is mounted so as to be parallel to the outer peripheral edge on the long side of the element mounting member 110.

As shown in FIGS. 1 to 2, the element mounting member 110 is mainly composed of a substrate portion 110 a, a first frame portion 110 b, and a second frame portion 110 c.
In the element mounting member 110, a first frame portion 110b is provided on one main surface of the substrate portion 110a to form a first recess space K1. In addition, a second frame portion 110c is provided on the other main surface of the element mounting member 110 to form a second recessed space K2.
In addition, the board | substrate part 110a and the 2nd frame part 110c which comprise this element mounting member 110 are formed by laminating | stacking multiple ceramic materials, such as an alumina ceramic and a glass-ceramic, for example.
The first frame portion 110b is made of a metal such as 42 alloy or Kovar, and has a frame shape with a punched center.
The first frame portion 110b is connected to the sealing conductor film HB provided so as to surround the outer periphery of one main surface of the substrate portion 110a by brazing or the like.
Two pairs of piezoelectric vibration element mounting pads 111 are provided on one main surface of the substrate portion 110a exposed in the first recess space K1.
1 to 3, the element mounting member 110 has a second recessed space K2 formed by the other main surface of the substrate portion 110a and the second frame portion 110c.
A thermistor element mounting pad 112 is provided on the other main surface of the substrate portion 110a exposed in the second recess space K2.

External connection electrode terminals G are provided at the four corners of the main surface opposite to the surface on which the piezoelectric vibration element mounting pad 111 of the second frame portion 110c of the element mounting member 110 is provided.
The external connection electrode terminal G includes two pairs of piezoelectric vibration element electrode terminals G1 and two pairs of thermistor element electrode terminals G2.
The two pairs of piezoelectric vibration element electrode terminals G <b> 1 are provided diagonally to the other main surface of the second frame portion 110 c of the element mounting member 110.
The two pairs of thermistor element electrode terminals G2 are provided at two corners of the second frame part 110c different from the positions where the piezoelectric vibration element electrode terminals G1 are provided. In other words, the thermistor element electrode terminal G2 is provided at a diagonal of the second frame portion 110c different from the diagonal at which the piezoelectric vibration element electrode terminal G1 is provided.

As shown in FIG. 3, the third recess space K3 is provided between two external connection electrode terminals G that are adjacent to each other on the same side of the second frame portion 110c of the element mounting member 110. .
The third recessed space K3 is provided between two adjacent external connection electrode terminals G so as to be connected to the second recessed space K2.
In the third recess space K3, a portion of the thermistor element wiring pattern 116 is exposed. The length L1 of the third recess space K3, which is the long side direction of the element mounting member 110b, is about 100 to 200 μm, for example.

The piezoelectric vibration element mounting pad 111 and any one of the external connection electrode terminals G include a piezoelectric vibration element wiring pattern 113 having a portion formed on the substrate portion 110a in the second recess space K2 of the element mounting member 110. The first via conductor 114 provided in the substrate part 110a is connected to the second via conductor 115 formed inside the substrate part 110a and the second frame part 110c.
That is, as shown in FIGS. 4 and 5, the piezoelectric vibration element mounting pad 111 is connected to one end of the piezoelectric vibration element wiring pattern 113 via the first via conductor 114. The other end of the piezoelectric vibration element wiring pattern 113 is connected to the piezoelectric vibration element electrode terminal G <b> 1 via the second via conductor 115. Therefore, the piezoelectric vibration element mounting pad 111 is electrically connected to the piezoelectric vibration element electrode terminal G1.

Further, the thermistor element mounting pad 112 and the thermistor element electrode terminal G2 have a portion formed on the substrate portion 110a in the second recessed space K2 of the element mounting member 110 and the second wiring pattern 116 for the thermistor element. They are connected by a third via conductor 117 formed inside the frame part 110c.
That is, as shown in FIGS. 5A and 5B, the thermistor element mounting pad 112 is connected to one end of the thermistor element wiring pattern 116. The other end of the thermistor element wiring pattern 116 is connected to the thermistor element electrode terminal G <b> 2 via the third via conductor 117. Therefore, the thermistor element mounting pad 112 is electrically connected to the thermistor element electrode terminal G2.

As shown in FIGS. 3 (a) and 3 (b), two pairs of thermistor element wiring patterns 116 exposed on the bottom surface of the second recessed space K2 are arranged in the third recessed space K3. The mounting member 110 is provided in a position that is parallel to the outer peripheral edge of the long side and is symmetrical with respect to a center line CL (described later) provided on the inner bottom surface of the second recessed space K2.
That is, the two pairs of thermistor element wiring patterns 116 are provided in parallel with the mounted thermistor element 140.
As shown in FIG. 5, the center line CL passes through the center point CP of the inner bottom surface of the second recess space K <b> 2 of the element mounting member 110 and is drawn parallel to the short side direction of the outer peripheral edge of the element mounting member 100. And

The bump BP <b> 1 is provided on the main surface of the pair of thermistor element wiring patterns 116, and is provided so as to be parallel to the outer peripheral edge portion on the short side of the element mounting member 110.
The bump BP1 is formed by an alumina coat containing alumina, for example.
The distance L2 between the bump BP1 and the thermistor element mounting pad 112 shown in FIG. 3A is, for example, 50 to 150 μm.
Further, the length L3 in the long side direction of the bump BP1 shown in FIG. 3A is, for example, 200 to 300 μm, and the length L4 in the short side direction of the bump BP1 is, for example, 100 to 200 μm. The length in the thickness direction of the bump BP1 is, for example, 10 to 20 μm.
The bump BP1 may be provided in a planar shape toward the second frame portion 110b.

Further, the lengths L1 of the two pairs of thermistor element wiring patterns 116 exposed on the inner bottom surface of the second recess space K2 are equal. That is, the length L1 of the two pairs of thermistor element wiring patterns 116 is the same length.
The length L1 of the two pairs of thermistor element wiring patterns 116 exposed on the inner bottom surface of the second recessed space K2 is, for example, 200 to 250 μm.

  The lid 130 is made of, for example, an Fe—Ni alloy (42 alloy), an Fe—Ni—Co alloy (Kovar), or the like. Such a lid 130 hermetically seals the first recessed space K1 with nitrogen gas or vacuum. Specifically, the lid body 130 is placed on the first frame portion 110b of the element mounting member 110 in a predetermined atmosphere, and a part of the metal of the surface of the first frame portion 110b and the metal of the lid body 130. By applying a predetermined current so as to be welded and performing seam welding, the first frame portion 110b is joined.

  The conductive adhesive DS contains a conductive powder as a conductive filler in a binder such as a silicone resin. As the conductive powder, aluminum (Al), molybdenum (Mo), tungsten (W ), Platinum (Pt), palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or a combination thereof is used. .

  The conductive bonding material HD is made of, for example, silver paste or lead-free solder. Further, the conductive bonding material HD contains an added solvent for adjusting the viscosity to be easily applied.

  When the element mounting member 110 is made of alumina ceramic, the piezoelectric vibration element mounting pad 111 and the thermistor element are mounted on the surface of a ceramic green sheet obtained by adding and mixing an appropriate organic solvent or the like to a predetermined ceramic material powder. A first via conductor is formed in a through-hole previously formed by punching a ceramic green sheet with a conductive paste to be used as the pad 112, the sealing conductive film HB, the electrode terminal G for external connection, etc. 114, the second via conductor 115, the third via conductor 117, etc. are manufactured by applying a conventional paste by screen printing, laminating a plurality of these, press molding, and firing at a high temperature. Is done.

  In addition, a nozzle is provided with a third recessed space K3 that projects between two external connection electrode terminals G that are adjacent to each other on the same side of the second frame portion 110c of the element mounting member 110. When applying the conductive bonding material HD (not shown), it is possible to prevent the conductive bonding material HD from adhering to a portion other than the thermistor element mounting pad 112 of the element mounting member 110 and reduce a short circuit. . Further, the necessary length of the thermistor element wiring pattern 116 can be ensured.

  According to the piezoelectric device 100 of the present invention, the two pairs of thermistor element wiring patterns 116 exposed on the inner bottom surface of the second recess space K2 are arranged on the long side of the element mounting member 110 in the third recess space K3. The element mounting member is provided on the main surface of the pair of thermistor element wiring patterns 116 provided in a position parallel to the outer peripheral edge portion and symmetrical with respect to the center line CL of the inner bottom surface of the second recessed space K2. Since the bump BP1 is provided so as to be parallel to the outer peripheral edge portion 110 and the short side, the conductive bonding material HD is applied to the thermistor element mounting pad 112 and then conductive along the thermistor element wiring pattern 116. It is possible to reduce the flow of the conductive bonding material HD and maintain the conductive bonding material HD sufficient to maintain the bonding strength of the thermistor element 140. Therefore, it is possible to reduce the thermistor element 140 from being detached from the thermistor element mounting pad 112.

  Further, according to the piezoelectric device 100 of the present invention, the bumps BP1 are provided on the main surface of the pair of thermistor element wiring patterns 116 so as to be parallel to the outer peripheral edge of the element mounting member 110 on the short side. Therefore, the thermistor element 140 can be positioned because the thermistor element 140 is not displaced from the bump BP1 toward the wall in the third recess space K3.

In addition, this invention is not limited to the said embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.
For example, in the above-described embodiment, the case where crystal is used as the piezoelectric material constituting the piezoelectric vibration element 120 has been described. However, as other piezoelectric materials, lithium niobate, lithium tantalate, or piezoelectric ceramics is used as the piezoelectric material. The piezoelectric vibration element used may be used.

DESCRIPTION OF SYMBOLS 110 ... Element mounting member 110a ... Board | substrate part 110b ... 1st frame part 110c ... 2nd frame part 111 ... Piezoelectric vibration element mounting pad 112 ... Thermistor element mounting pad 116. ..Wiring pattern for thermistor element 120... Piezoelectric vibration element 121... Quartz element plate 122... Excitation electrode 123 .. Extraction electrode 130 ... Lid 140 .. Thermistor element 100. Piezoelectric device K1... First recess space K2... Second recess space K3... Third recess space DS... Conductive adhesive HD. Stopping conductor film G: Electrode terminal for external connection G1: Electrode terminal for piezoelectric vibration element G2: Electrode terminal for thermistor element CL: Center line BP1: Bump

Claims (1)

An element mounting member comprising a substrate portion, a first frame portion provided on one main surface of the substrate portion, and a second frame portion provided on the other main surface of the substrate portion;
A piezoelectric vibration element mounted on a piezoelectric vibration element mounting pad provided on the main surface of the substrate part exposed in a first recess space formed by the substrate part and the first frame part;
A thermistor element mounting pad provided on the main surface of the substrate portion exposed in the second recess space formed by the substrate portion and the second frame portion is mounted using a conductive bonding material. A thermistor element;
A pair of thermistor element wiring patterns connected to the thermistor mounting pad;
A lid for hermetically sealing the first recessed space;
The second frame portion is composed of two pairs of piezoelectric vibration element electrode terminals and two pairs of thermistor element electrode terminals at the four corners of the surface facing the same direction as the other main surface of the substrate portion. An electrode terminal for external connection;
A third recess space provided between two external connection electrode terminals adjacent to each other on the same side of the second frame portion of the element mounting member,
The two pairs of thermistor element wiring patterns exposed on the bottom surface in the second recess space are parallel to the outer peripheral edge of the long side of the element mounting member in the third recess space, and the second recess space. It is provided at a position that is line symmetric with respect to the center line of the inner bottom surface,
Bumps are provided on the main surface of the pair of thermistor element wiring patterns so as to be parallel to the outer peripheral edge on the short side of the element mounting member .

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