JP2020088635A - Piezoelectric device and electronic apparatus - Google Patents

Abstract

To provide a piezoelectric device that can reduce variations in characteristics.SOLUTION: In a crystal oscillator 1, a substrate part 110a has a rectangular shape. A second frame part 110c includes a pair of portions located in areas on a pair of short sides of the substrate part 110a of an undersurface of the substrate part 110a, and forms a second concave part K2 between the pair of portions. Electrode pads 111 are located on a top face of the substrate part 110a. A connection pad 115 is located on the undersurface of the substrate part 110a in the second frame part 110c. A plurality of external terminals 113 are located on the undersurface of the second frame part 110c. A crystal element 120 is mounted on the electrode pad 111. A temperature-sensitive element 130 is mounted on the connection pad 115. The thickness in the vertical direction of the substrate part 110a is 80 μm or more and 150 μm or less.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a piezoelectric device and an electronic device including the piezoelectric device. The piezoelectric device is, for example, a crystal oscillator or a crystal oscillator.

A piezoelectric device having a so-called H-type package is known (for example, Patent Document 1). The H-type package has a substrate, a first frame portion located on the upper surface of the substrate, and a second frame portion located on the lower surface of the substrate. A crystal vibrating element is mounted in a region surrounded by the first frame portion on the upper surface of the substrate. A thermistor or an IC (Integrated Circuit) is mounted in a region surrounded by the second frame portion on the lower surface of the substrate. External terminals for mounting the piezoelectric device on a circuit board or the like of an electronic device are provided on the lower surface of the second frame portion.

Further, there is also known a configuration in which a wiring board is used to realize a pseudo H-type package (for example, Patent Document 2). In this configuration, a container-type package is used as the portions corresponding to the substrate and the first frame portion. A wiring board having an opening is used as a portion corresponding to the second frame portion. The container-type package is mounted on the upper surface of the wiring board so as to cover the opening, thereby forming a pseudo H-type package. External terminals are provided on the lower surface of the wiring board, similarly to the second frame portion. In Patent Document 2, the external terminal is separated from the outer edge of the wiring board.

It is known that crystal oscillators and crystal oscillators exhibit so-called hysteresis characteristics. That is, in the case where the oscillation frequency changes due to a temperature change, the oscillation frequency (error from another point of view) is different between when the temperature rises and when the temperature falls even for the same temperature. A package structure for reducing such hysteresis characteristics has also been proposed (for example, Patent Document 3).

JP 2000-49560 A JP, 2016-082538, A JP, 2010-087715, A

For example, it is desired to provide a piezoelectric device and electronic equipment that can reduce fluctuations in characteristics such as hysteresis characteristics.

A piezoelectric device according to an aspect of the present disclosure includes a rectangular substrate and a pair of portions located in a region of a lower side of the substrate on a shorter side of the substrate, and A frame body forming a recess between a pair of portions, an electrode pad located on the upper surface of the substrate, a connection pad located on the lower surface of the substrate in the frame body, and the frame body. A plurality of external terminals located on the lower surface of the electrode, a piezoelectric element mounted on the electrode pad, a temperature-sensitive component mounted on the connection pad, and a lid body hermetically sealing the piezoelectric element. And the vertical thickness of the substrate is 80 μm or more and 150 μm or less.

In one example, a value obtained by dividing the vertical thickness of the substrate by the length of the long side of the substrate is 0.050 or more and 0.094 or less.

In one example, the entire electrode pad is located outside the recess when seen in a plan view.

In one example, the recess and the temperature-sensitive component have a shape in which a pair of long sides of the substrate are opposed to each other in a longitudinal direction.

In one example, in the plan view, the centroid of the recess is located on the opposite side of the centroid of the substrate from the electrode pad.

In one example, the substrate and the frame are directly bonded to each other.

In one example, the piezoelectric device includes a mounting terminal located on the lower surface of the substrate, a mounting pad located on the upper surface of the frame, and a conductive material that joins the mounting terminal and the mounting pad. And a bonding material.

In one example, the piezoelectric device further includes an insulating resin that covers the temperature-sensitive component and is in close contact with the lower surface of the substrate.

In one example, the resin is also located in a gap between the lower surface of the substrate and the upper surface of the frame body.

An electronic apparatus according to an aspect of the present disclosure includes the piezoelectric device, a base, and four external pads located on the surface of the base and joined to the four external terminals. .

According to the above configuration, it is possible to reduce fluctuations in characteristics.

It is an exploded perspective view showing composition of a crystal oscillator concerning a 1st embodiment. It is sectional drawing in the II-II line of FIG. It is a bottom view of the crystal oscillator of FIG. It is a bottom view of the crystal oscillator concerning a modification. It is a bottom view of the crystal oscillator concerning a 2nd embodiment. It is an exploded perspective view showing composition of a crystal oscillator concerning a 3rd embodiment. FIG. 7 is a sectional view taken along line VII-VII of FIG. 6. It is a conceptual diagram for demonstrating the evaluation item about an Example. It is a figure which shows the hysteresis characteristic of the crystal oscillator which concerns on an Example.

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. It should be noted that, for convenience, the drawings may include a Cartesian coordinate system including D1, A, D2, and D3 axes. The crystal unit according to the embodiment may be used as either upward or downward in any direction. However, hereinafter, for convenience, terms such as the upper surface or the lower surface may be used with the +D3 side as the upper side. Further, in the following description, the plan view refers to viewing in the D3 direction unless otherwise specified.

After the description of the first embodiment, basically, only the differences from the previously described embodiments will be described. Matters not particularly mentioned may be the same as those in the embodiment described above. In addition, for the sake of convenience of description, the same reference numerals may be given to configurations corresponding to each other between the plurality of embodiments, even if there are differences.

[First Embodiment]
FIG. 1 is an exploded perspective view showing the configuration of the crystal resonator 1 according to the first embodiment. FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3 is a bottom view of the crystal unit 1. In FIG. 3, some of the constituent elements (resin 135) are not shown, and some of the constituent elements (temperature sensitive element 130) are indicated by dotted lines.

The crystal unit 1 is generally configured as a thin rectangular parallelepiped electronic component having sides parallel to the D1, D2 and D3 axes. For example, as shown in FIG. 2, the crystal unit 1 is surface-mounted on the circuit board 180, and constitutes the electronic device 190 together with the circuit board 180. The crystal unit 1 is configured as a so-called crystal unit with a temperature-sensitive element, generates vibrations used to generate an oscillation signal and the like, and converts temperature into an electric signal. This electric signal is used, for example, by an electronic circuit of the circuit board 180 to compensate for a change in the frequency characteristic of the crystal unit 1 caused by a temperature change.

As shown in FIG. 1 in particular, the crystal unit 1 includes an element mounting member 100, a crystal element 120 mounted on the element mounting member 100 from the upper surface side, and a crystal element 120 mounted on the element mounting member 100 from the lower surface side. It has a temperature sensitive element 130 and a lid 140 that seals the crystal element 120. The element mounting member 100 and the lid 140 constitute a package of the crystal unit 1. The temperature sensitive element 130 is at least partially covered with the resin 135 as shown in FIG.

(Element mounting member)
The element mounting member 100 has an insulating base 110 and various conductors located on the surface and/or inside of the insulating base 110. The various conductors, for example, mount the pair of electrode pads 111 for mounting the crystal element 120, the pair of connection pads 115 for mounting the temperature sensitive element 130, and the crystal resonator 1 on the circuit board 180. Are four external terminals 113.

The pair of electrode pads 111 are electrically connected to two of the four external terminals 113 by the wiring conductor of the element mounting member 100. The pair of connection pads 115 are electrically connected to the other two of the four external terminals 113 by the wiring conductor of the element mounting member 100. Consequently, the crystal element 120 and the temperature sensitive element 130 are electrically connected to the circuit board 180 via the external terminal 113.

Although not shown in the drawings, the wiring conductor may be appropriately constituted by a layered conductor and/or a via conductor located on the surface and/or inside of the element mounting member 100. In FIG. 3, two wiring patterns 116 that form a part of the wiring conductor that connects the two connection pads 115 and the two external terminals 113 are shown.

(Insulating substrate)
The insulating base 110 has a substrate portion 110a, a first frame portion 110b located on the upper surface of the substrate portion 110a, and a second frame portion 110c located on the lower surface of the substrate portion 110a. A first concave portion K1 is formed by the upper surface of the substrate portion 110a and the inner peripheral surface of the first frame portion 110b. The lower surface of the substrate portion 110a and the inner peripheral surface of the second frame portion 110c form a second recess K2. The first recess K1 is hermetically sealed by the lid 140. The insulating base 110 is H-shaped in cross section, and thus a so-called H-type package is formed.

The substrate part 110a is generally a plate having a constant thickness. The plane shape is a rectangular shape. More specifically, the planar shape of the substrate portion 110a is a rectangle, and has a pair of long sides and a pair of short sides. The ratio of the long side to the short side may be set appropriately. For example, the long side is 1.1 times or more, 1.2 times or more, or 1.3 times or more, and 1.5 times or less, 1.4 times or less, 1.3 times or more, with respect to the short side. Below, the lower limit and the upper limit may be appropriately combined as long as there is no contradiction.

In the case of the rectangular shape, the corner portion of the rectangle may be formed with a concave portion (for example, castellation) (illustrated example) or may be chamfered with a flat surface or a curved surface. The same applies to other members. The same applies to the case of a polygonal shape.

Each of the first frame portion 110b and the second frame portion 110c has a frame shape having a substantially constant thickness. The thickness of the first frame portion 110b may be thinner, equal to, or thicker than the thickness of the substrate portion 110a. In addition, the thickness of the second frame portion 110c may be thinner than, the same as, or thicker than the thickness of the substrate portion 110a and/or the first frame portion 110b. In the illustrated example, the thickness of the substrate portion 110a is smaller than the thickness of the first frame portion 110b and the second frame portion 110c.

In the first frame portion 110b (first concave portion K1), the shape (planar shape) of the cross section orthogonal to the D3 axis and the dimension in the cross section are the same as the board portion 110a side (-D3 side) and the opposite side (+D3 side). Are almost the same. Similarly, in the second frame portion 110c (second concave portion K2), the shape (planar shape) of the cross section orthogonal to the D3 axis and the dimension in the cross section are the board portion 110a side (+D3 side) and the opposite side (-D3). Side) is almost the same. However, unlike the illustrated example, in each of the first frame portion 110b and the second frame portion 110c, the planar shape and the dimension thereof may be different between the substrate portion 110a side and the opposite side. Note that in this case, the description of the planar shapes and the dimensions of the first frame portion 110b and the second frame portion 110c in the present disclosure may be applied to both the substrate 110a side and the opposite side thereof. It may be applied to either one.

In a plan view, the inner edge and the outer edge of the first frame portion 110b are rectangular with four sides parallel to the four sides of the substrate portion 110a. From another viewpoint, the first frame portion 110b has a pair of long sides and a pair of short sides. The outer edge of the first frame portion 110b substantially coincides with (overlaps with) the outer edge of the substrate portion 110a. The width (width of each side) from the inner edge to the outer edge of the first frame portion 110b is, for example, constant on each side of the first frame portion 110b. The widths of the four sides may be the same or different from each other.

The first recess K1 is, for example, configured to be relatively wide in a plan view. As an example, the area of the first recess K1 is 1/2 or more or 2/3 or more of the area of the substrate 110a. In another aspect, the width of each side of the first frame portion 110b is, for example, 1/4 or less, 1/5 or less, 1/6 or the length of the long side and/or the short side of the substrate portion 110a. It is 1/7 or less.

In a plan view, the centroid (center) of the first recess K1 roughly coincides with the centroid of the substrate 110a. For confirmation, the centroid is the point at which the first moment of area with respect to the axis passing through the point becomes 0 in the planar shape. The distance between the centroid of the substrate 110a and the centroid of the first recess K1 is, for example, 1/5 or less or 1/10 or less of the length of the long side of the substrate 110a.

In a plan view, the outer edge of the second frame portion 110c has a rectangular shape having four sides parallel to the four sides of the substrate portion 110a. More specifically, the outer edge of the second frame 110c substantially coincides with (overlaps with) the outer edge of the substrate 110a. From this, in the following description, the relative position and size of the external terminal 113 or the second recess K2 with respect to the outer edge of the substrate portion 110a or a region formed by the outer edge, and the outer edge of the second frame portion 110c or the outer edge thereof. There is no distinction from the relative position and size of the external terminal 113 or the second recess K2 with respect to the region formed by, and only one may be referred to.

In plan view, the shape of the inner edge (second recess K2) of the second frame 110c may be an appropriate shape such as a rectangular shape, a circular shape, an elliptical shape, or a polygonal shape other than a rectangular shape. In the illustrated example, the shape of the second recess K2 is a rectangle having a short side parallel to the long side of the substrate 110a and a long side parallel to the short side of the substrate 110a, and the corners of the rectangle are relatively chamfered. It is said that. From another viewpoint, the shape of the second recess K2 is such that the longitudinal direction of the substrate portion 110a is the lateral direction and the lateral direction of the substrate portion 110a is the longitudinal direction.

In plan view, the area of the second recess K2 is smaller than the area of the first recess K1, for example. As an example, the area of the second recess K2 is 4/5 or less or 3/4 or less of the area of the substrate unit 110a and/or the first recess K1. Further, from another viewpoint, the width of the short side of the second frame portion 110c is, for example, ¼ or more or ⅓ or more of the length of the long side of the substrate portion 110a.

In plan view, the second recess K2 is located, for example, on the center side with respect to the substrate 110a. More specifically, for example, the centroid of the substrate 110a is located in the second recess K2. The distance between the center of the substrate 110a and the center of the second recess K2 is, for example, 1/4 or less or 1/10 or less of the length of the long side of the substrate 110a.

The substrate part 110a, the first frame part 110b, and the second frame part 110c are made of, for example, a ceramic material such as alumina ceramics or glass-ceramics. The board part 110a, the first frame part 110b, and the second frame part 110c may be made of the same material, or may be made of different materials. Each of the substrate portion 110a, the first frame portion 110b, and the second frame portion 110c may be one in which an insulating layer is used, or a plurality of insulating layers, from the viewpoint of material and/or manufacturing method. It may be laminated.

The board part 110a and the first frame part 110b are, for example, integrally formed. In addition, the substrate portion 110a and the second frame portion 110c are integrally formed, for example. The integral formation means that, for example, the insulating material forming the substrate portion 110a and the insulating material forming the first frame portion 110b (or the second frame portion 110c) are in direct contact with each other and joined. Good. Therefore, the integral formation does not require that both materials are the same. For example, the substrate portion 110a and the first frame portion 110b (and/or the second frame portion 110c) may be integrally formed by stacking and firing ceramic green sheets having different component configurations. ..

In the figure, the boundaries of the substrate portion 110a, the first frame portion 110b, and the second frame portion 110c are clearly shown. However, the boundary may not be specified from the viewpoint of materials and the like. For example, the substrate portion 110a, the first frame portion 110b, and the second frame portion 110c may be conceptualized by the presence of the first concave portion K1, the second concave portion K2, and/or the conductor layer interposed between the respective portions.

(Electrode pad)
The pair of electrode pads 111 is composed of a conductor layer located on the upper surface of the substrate 110a. The material and thickness of the conductor layer may be set appropriately. The pair of electrode pads 111 are arranged, for example, in the direction along one short side of the substrate portion 110a, and are also adjacent to the inner peripheral surface of the first frame portion 110b. Adjacent here is that the distance (D1 direction) from the inner peripheral surface of the first frame 110b is smaller than the diameter of the electrode pad 111 in the D1 direction (for example, the maximum diameter when the electrode pad 111 is not rectangular). May be The electrode pad 111 may be in contact with or separated from the first frame 110b. The planar shape of the electrode pad 111 may be an appropriate shape, for example, a rectangular shape.

As described above, in the present embodiment, the second recess K2 is smaller than the first recess K1 in plan view. From another viewpoint, a region of the upper surface of the substrate 110a surrounded by the first frame 110b has a region that does not overlap with the second recess K2. Then, as shown in FIG. 2, for example, the pair of electrode pads 111 are wholly located in a region of the substrate portion 110a that does not overlap the second recess K2. Of course, unlike the illustrated example, the pair of electrode pads 111 may partially overlap the second recess K2.

(Connection pad)
The connection pad 115 is composed of a conductor layer located on the lower surface of the substrate section 110a. The material and thickness of the conductor layer may be set appropriately. The pair of connection pads 115 are arranged, for example, in a direction in which the long sides of the substrate portion 110a are opposed to each other on the center side of the substrate portion 110a (D2 direction; from another perspective, the longitudinal direction of the second recess K2). The planar shape of the connection pad 115 may be an appropriate shape, for example, a rectangular shape.

(External terminal)
The external terminal 113 is composed of a conductor layer located on the lower surface of the second frame portion 110c. The material and thickness of the conductor layer may be set appropriately. The four external terminals 113 are located, for example, on the four corner sides of the lower surface of the second frame portion 110c. The planar shape of the external terminal 113 may be an appropriate shape. In the example of FIG. 3, the external terminal 113 has a shape in which a part on the second recess K2 side is removed from a rectangle having four sides parallel to the four sides of the outer edge of the second frame 110c. The edge of the removed portion may be a straight line, a combination of two or more straight lines (example shown), or a curved line.

On the lower surface of the second frame portion 110c, the conductor layer forming the external terminal 113 may have a portion other than the external terminal 113. In the example of FIG. 3, the conductor layer has the connection portion 114 located between the external terminal 113 and the concave portion 110cc (castellation) at the corner of the second frame portion 110c. The connecting portion 114 is connected to the castellation conductor 117 (FIG. 1) formed in the recess 110cc. The connecting portion 114 and the castellation conductor 117 may not be provided.

When the conductor layer located on the lower surface of the second frame portion 110c also constitutes a portion other than the external terminal 113 as described above, the external terminal 113 and the portion other than the external terminal 113 have a shape and/or function. May be reasonably distinguished from. For example, in the planar shape of the conductor layer, the portion that specifically projects may be regarded as a portion other than the external terminal 113. In the example of FIG. 3, the side 113a of the external terminal 113 facing the side 110ca of the outer edge of the second frame 110c can be recognized. The connecting portion 114 projects from a part of the side 113a (for example, ¼ or less of the length of one side 113a). Because of this, the external terminal 113 and the connecting portion 114 are distinguished from each other.

The four external terminals 113 are separated from the outer edges (long sides and short sides) of the lower surface of the second frame portion 110c. Specifically, for example, in the example of FIG. 3, each of the external terminals 113 has two sides that form one corner of the four sides 110ca of the outer edge of the second frame 110c on the side where the self is located. The outer edge includes two sides 113a facing 110ca (one long side and one short side adjacent to each other). From another viewpoint, the side 113a extends along the side 110ca of the outer edge of the second frame 110c (for example, in parallel). The side 113a and the side 110ca facing each other are separated by a distance s1. The distance s1 may be the same between the two sides 113a of one external terminal 113 (example shown), or may be different. In addition, the distance s1 may be the same among the four external terminals 113 (example shown), or may be different.

Further, from another viewpoint, when considering the smallest rectangular region R1 including the external terminal 113, the area S2 of the rectangular region R1 is formed by the outer edge of the second frame portion 110c (the substrate portion 110a from another viewpoint). Is smaller than the area S1 of the rectangular region (the chamfer of the concave portion 110cc or the corner can be ignored). In the illustrated example, the rectangular region R1 has four sides that overlap the two sides 113a of the four external terminals 113 (eight sides 113a in total).

In the plurality of external terminals 113, the relative relationship between the position and the role may be set appropriately. For example, of the four external terminals 113, two diagonally located on the lower surface of the second frame portion 110c are electrically connected to the pair of electrode pads 111. The other two external terminals 113 located diagonally are electrically connected to the pair of connection pads 115.

(Lid)
The lid 140 is made of, for example, an alloy containing at least one of iron, nickel and cobalt. The outer peripheral portion of the lid 140 is joined to the upper surface of the first frame portion 110b over the entire circumference. Thereby, the first recess K1 is sealed. The first recess K1 may be filled with a gas or may be in a vacuum state. The gas is, for example, nitrogen. The vacuum is actually a state of being depressurized below atmospheric pressure.

The lid 140 and the first frame portion 110b may be joined by an appropriate method. For example, both are joined by joining the sealing conductor pattern 112 provided on the upper surface of the first frame 110b and the sealing member 141 provided on the lower surface of the lid 140 by seam welding. There is.

(Crystal element)
The crystal element 120 includes, for example, a crystal piece 121, a pair of excitation electrodes 122 for applying a voltage to the crystal piece 121, and a pair of connection for mounting the crystal element 120 on a pair of electrode pads 111. And an electrode 123. The pair of excitation electrodes 122 and the pair of connection electrodes 123 are connected by a pair of extraction electrodes 124.

The crystal piece 121 is formed, for example, in a flat plate shape having a substantially rectangular planar shape. From another viewpoint, the crystal blank 121 has a shape having a longitudinal direction and a lateral direction. The crystal piece 121 is, for example, an AT-cut crystal piece. Although not particularly shown, the crystal piece 121 may be various known pieces other than the illustrated example. For example, the crystal element may be a so-called tuning fork type. Further, when the crystal piece 121 has a plate shape, it may be a so-called mesa type having a thick central portion, or a so-called convex type that becomes thinner as it approaches the outer edge. May be. Further, the planar shape (shape of the outer edge) of the plate-shaped crystal piece may be a shape other than a rectangle such as an ellipse.

The excitation electrode 122, the connection electrode 123, and the extraction electrode 124 are formed of a conductor layer that overlaps the surface of the crystal piece 15. The material and thickness of the conductor layer may be set appropriately. The pair of excitation electrodes 122 are located on the center side of the pair of main surfaces (front and back of the plate shape) of the crystal piece 121 and face each other with the crystal piece 121 interposed therebetween. The pair of connecting electrodes 123 is, for example, on at least one main surface (both main surfaces in the illustrated example) of at least one of the crystal pieces 121, on one side in the longitudinal direction of the crystal piece 121 with respect to the pair of excitation electrodes 122 ( It is located on one short side). Further, for example, the connection electrodes 123 are arranged along one short side of the crystal piece 121. The pair of extraction electrodes 124 connect the pair of excitation electrodes 122 and the pair of connection electrodes 123 by the shortest path. The specific shapes of the excitation electrode 122, the connection electrode 123, and the extraction electrode 124 may be set appropriately, and in the illustrated example, they are rectangular.

(Mounting of crystal element)
As shown in FIG. 2, the crystal element 120 is mounted on the element mounting member 100 by bonding the connection electrode 123 and the electrode pad 111 with the conductive adhesive 150. As described above, since the pair of connecting electrodes 123 is located on one side in the longitudinal direction of the crystal element 120, the crystal element 120 is supported on one end side like a cantilever and the other end is It is considered a free end. The conductive adhesive 150 is made of resin mixed with a conductive filler. The resin is, for example, a thermosetting resin. Specific materials of the resin and the conductive filler, the diameter of the conductive filler, and the like may be appropriately set.

(Temperature sensor)
The temperature sensitive element 130 is configured by, for example, an element whose electrical characteristic (for example, resistance value) changes according to temperature change. Examples of such a material include a thermistor, a resistance temperature detector, and a diode. The temperature sensitive element 130 is formed, for example, in a substantially rectangular parallelepiped shape, and has a pair of connection terminals 131 at both ends thereof. In the rectangular parallelepiped shape of the temperature sensitive element 130, the connection terminal 131 is exposed at least on the surface facing the lower surface of the substrate section 110a. In the illustrated example, the connection terminal 131 is formed on each of the longitudinal end portions of the rectangular parallelepiped over the upper and lower surfaces, the side surfaces, and the end surface.

The pair of connection terminals 131 face the pair of connection pads 115, and are joined by the joining material 133 interposed therebetween. The bonding material 133 is composed of solder or a conductive adhesive.

(resin)
The resin 135 is made of, for example, a thermosetting resin (eg, epoxy resin). The resin 135 may include a filler. As the filler, for example, one having a coefficient of thermal expansion lower than that of resin (for example, SiO ₂ ) can be used. In addition, for example, a filler whose thermal conductivity is lower or higher than that of the resin may be added for adjusting the thermal conductivity.

The resin 135 may function as a so-called underfill, for example. Specifically, the resin 135 is, for example, filled between the lower surface of the substrate 110 a and the temperature sensitive element 130, and may be in close contact with these. Further, the resin 135 may be filled into the second recess K2 up to an appropriate position up to the opening surface (the lower surface of the second frame 110c).

Specifically, for example, the surface of the resin 135 on the opposite side (−D3 side) to the substrate section 110a may be located above (−D3 side) of the −D3 side surface of the temperature sensitive element 130. However, it may be located on the surface of the temperature sensing element 130 on the −D3 side (illustrated example), or may be located below the surface of the temperature sensing element 130 on the −D3 side. In other words, the resin 135 may be in close contact with a part of the side surface (at least one side surface. For example, all (four) side surfaces. The same applies hereinafter) of the temperature-sensitive element 130 on the +D3 side. , May be in close contact with the entire side surface of the temperature-sensitive element 130 (example shown), or may be in close contact with the side surface of the temperature-sensitive element 130 and the surface on the −D3 side of the temperature-sensitive element 130 ( The entire temperature sensitive element 130 may be covered).

Further, for example, the resin 135 may be in close contact with only a part of the lower surface of the substrate portion 110a among the surfaces forming the second recess K2, or the entire lower surface of the substrate portion 110a and the second frame. Of the inner peripheral surface (at least one surface. For example, all (six) surfaces. The same applies hereinafter) of the portion 110c, it may be in close contact with only a part of the substrate portion 110a side (illustrated example). The upper and lower surfaces of the lower surface of the substrate 110a and the inner peripheral surface of the second frame 110c may be in close contact with each other.

(Circuit board)
The circuit board 180 shown in FIG. 2 is formed of, for example, a known rigid board or flexible board, and has an insulating board 181 and an external pad 182 located on the upper surface of the insulating board 181. The external terminal 113 of the crystal unit 1 is bonded to the external pad 182 by a bonding material 183 such as solder. The bonding material 183 may be bonded over the entire lower surface of the external terminal 113 and/or the upper surface of the external pad 182 (for example, an area of 80% or more), or a portion that cannot be said to be large. May be joined to.

The electronic device 190 has, for example, although not shown in particular, an oscillation circuit and a temperature compensation circuit configured by the circuit board 180 and/or an IC mounted on the circuit board 180. The oscillator circuit applies an AC voltage to the crystal element 120 via two of the four external terminals 113 to generate an oscillation signal of a predetermined frequency. The temperature compensation circuit compensates for changes in the frequency characteristics of the crystal unit 1 due to changes in temperature. At this time, the temperature compensation circuit determines the compensation amount based on the detection signal (detection temperature) from the temperature sensing element 130 obtained through two of the four external terminals 113.

The electronic device 190 may be any device that uses an oscillation signal. For example, the electronic device 190 may be a mobile terminal, a personal computer (PC), a GPS (Global Positioning System) device, or an ECU (engine control unit).

(Example of dimensions)
An example of dimensions of each part of the crystal unit 1 will be given below.

The length of the long side of the substrate portion 110a may be, for example, 1.5 mm or more, 2.0 mm or more, or 3.0 mm or more, and may be 4.0 mm or less, 3.0 mm or less, or 2.0 mm or less. The above lower limit and upper limit may be appropriately combined unless they contradict each other. In addition, the length of the short side of the substrate unit 110a may be 1.0 mm or more, 1.5 mm or more, or 2.0 mm or more, for example, provided that the length of the long side of the substrate unit 110a is shorter. In addition, the length may be 3.0 mm or less, 2.0 mm or less, or 1.5 mm or less, and the above lower limit and upper limit may be appropriately combined as long as there is no contradiction. In this example, the value of the second decimal place is rounded off. For example, 1.5 mm or more includes 1.46 mm, and 4.0 mm or less includes 4.04 mm.

The thickness of the substrate part 110a may be, for example, 50 μm or more or 80 μm or more, 170 μm or less or 150 μm or less, and the above lower limit and upper limit may be appropriately combined. In this example, the value of the first decimal place is rounded off. The value obtained by dividing the thickness of the substrate portion 110a by the length of the long side of the substrate portion 110a may be, for example, 0.031 or more or 0.050 or more, and 0.106 or less or 0.094. The above lower limit and upper limit may be appropriately combined. In this example, the value of the fourth decimal place is rounded off.

The distance s1 from the outer edge of the lower surface of the second frame portion 110c of the external terminal 113 may be, for example, 10 μm or more or 30 μm or more, and may be 100 μm or less or 90 μm or less. , May be appropriately combined. In this example, the value of the first decimal place is rounded off. A value obtained by dividing the distance s1 by the length of the long side of the substrate 110a may be, for example, 0.013 or more or 0.038 or more, and may be 0.125 or less or 0.113 or less. Of course, the above lower and upper limits may be combined as appropriate. In this example, the value of the fourth decimal place is rounded off.

A value obtained by dividing the smallest rectangular area S2 surrounding the four external terminals 113 by the area S1 of the substrate 110a may be 0.73 or more or 0.75 or more, and 0.97 or less or 0.91. The above lower limit and upper limit may be appropriately combined. In this example, the value of the third decimal place is rounded off.

(Crystal oscillator manufacturing method)
As a method of manufacturing the crystal unit 1, various known manufacturing methods may be used. For example, the element mounting member 100 may be manufactured as follows.

First, a plurality of ceramic green sheets to be the substrate portion 110a, the first frame portion 110b, and the second frame portion 110c are prepared. The ceramic green sheets serving as the first frame portion 110b and the second frame portion 110c are provided with openings serving as the first recess K1 and the second recess K2. In addition, before or after the formation of the opening, conductive paste serving as various conductors (external terminals 113, electrode pads 111, connection pads 115, etc.) is arranged on the plurality of ceramic green sheets. Then, a plurality of ceramic green sheets are laminated to form a laminated body, and the laminated body is fired.

Further, a method of manufacturing the element mounting member 100 different from the above method can be mentioned. First, a plurality of ceramic green sheets to be the substrate portion 110a, the first frame portion 110b, and the second frame portion 110c are prepared. Conductive pastes serving as various conductors (external terminals 113, electrode pads 111, connection pads 115, etc.) are arranged on the plurality of ceramic green sheets. Next, the plurality of ceramic green sheets are laminated to obtain a laminated body. Next, the first recessed portion K1 and the second recessed portion K2 are formed by pressing the laminated body. Then, the laminated body is fired.

As described above, in the present embodiment, the crystal unit 1 includes the substrate (substrate portion 110a), the frame body (second frame portion 110c), the electrode pad 111, the connection pad 115, and the plurality of external terminals 113. It has a piezoelectric element (crystal element 120), a temperature-sensitive component (temperature-sensitive element 130), and a lid 140. The substrate part 110a has a rectangular shape. The second frame portion 110c includes a pair of portions (short side portions) located in a region of the lower surface of the substrate portion 110a on the side of the pair of short sides of the substrate portion 110a. A concave portion (second concave portion K2) is formed between the portions. The electrode pad 111 is located on the upper surface of the substrate 110a. The connection pad 115 is located on the lower surface of the substrate 110a in the second frame 110c. The plurality of external terminals 113 are located on the lower surface of the second frame portion 110c. The crystal element 120 is mounted on the electrode pad 111. The temperature sensitive element 130 is mounted on the connection pad 115. The lid 140 hermetically seals the crystal element 120. The thickness of the substrate portion 110a in the vertical direction is 80 μm or more and 150 μm or less.

Therefore, for example, fluctuations in the characteristics of the crystal unit 1 can be reduced. Specifically, it is as follows.

The characteristics of the crystal unit 1 are different before being mounted on the circuit board 180 and after being mounted on the circuit board 180. An example of such a characteristic is a hysteresis characteristic. As described above, the hysteresis characteristic is a characteristic in which a frequency error caused by a temperature change changes between a temperature increase and a temperature decrease even for the same temperature.

Here, the force generated due to the difference in thermal expansion between the element mounting member 100 of the crystal unit 1 and the circuit board 180 is transferred from the circuit board 180 to the element mounting member 100 via the external terminal 113 (and the bonding material 183). Reportedly. This force acts, for example, as a bending stress that tends to cause the insulating base 110 to warp (bend and deform). This bending stress is transmitted to the crystal element 120 via each electrode pad 111 and/or the pair of electrode pads 111. The bending stress transmitted to the crystal element 120 is one of the factors that cause the hysteresis characteristics to differ before being mounted on the circuit board 180 and after being mounted on the circuit board 180.

On the other hand, in the present embodiment, the thickness of the substrate portion 110a is set to 80 μm or more. Therefore, the warp of the substrate portion 110a is reduced as compared with the case where the substrate portion 110a is thinner than this. From another viewpoint, the bending stress is dispersed in the thickness direction of the substrate portion 110a. As a result, the bending stress transmitted to the crystal element 120 is reduced. As a result, the difference in the hysteresis characteristics of the crystal unit 1 before and after mounting is reduced.

Conventionally, various proposals have been made regarding the shape and dimensions of the crystal unit 1 so as to reduce the hysteresis characteristics before mounting. Therefore, by reducing the difference between the hysteresis characteristics before and after mounting, the hysteresis characteristics can be reduced after mounting. From another viewpoint, various proposals for reducing the hysteresis characteristic before mounting can be utilized. By reducing the hysteresis characteristic, for example, the accuracy of temperature compensation is improved.

In addition, since the thickness of the substrate portion 110a is 150 μm or less, for example, as compared with the case where the substrate portion 110a is thicker, the crystal element 120 and the temperature sensitive element 130 separated from each other by the substrate portion 110a. The probability of temperature deviations is reduced. As a result, the accuracy of temperature compensation is improved.

Further, in the present embodiment, a value (normalized thickness) obtained by dividing the thickness of the substrate in the vertical direction by the length of the long side of the substrate is 0.050 or more and 0.094 or less (fourth decimal place). Shall be rounded off).

In this case, for example, since the normalized thickness is 0.050 or more, it is easy to reduce the warpage of the substrate unit 110a. Further, since the normalized thickness is 0.094 or less, it is easy to reduce the difference in temperature between the crystal element 120 and the temperature sensitive element 130.

Further, in the present embodiment, the substrate portion 110a and the second frame portion 110c are directly joined. That is, both are integrally formed.

In this case, for example, stress is likely to be transmitted from the second frame portion 110c to the substrate portion 110a. Therefore, the effect of reducing the bending stress immediately below the electrode pad 111 due to the relatively thick substrate portion 110a is likely to appear.

Further, in the present embodiment, the entire electrode pad 111 is located outside the recess (the second recess K2) when seen in a plan view.

In this case, for example, immediately below the electrode pad 111, not only the thickness of the substrate portion 110a but also the thickness of the second frame portion 110c is ensured. Therefore, as compared with the case where the electrode pad 111 overlaps the second recess K2, the warpage of the insulating base 110 immediately below the electrode pad 111 is reduced. From another viewpoint, the bending stress is dispersed immediately below the electrode pad 111 in the thickness direction of the insulating base 110. As a result, the bending stress transmitted to the crystal element 120 via the electrode pad 111 is reduced. As a result, the effect of reducing the difference in hysteresis characteristics before and after mounting is improved.

Further, in the present embodiment, the second recess K2 and the temperature sensitive element 130 have a shape in which the longitudinal direction is the facing direction (D2 direction) of the pair of long sides of the substrate 110a.

In this case, for example, it is easy to secure the thickness of the mounting substrate 110 immediately below the electrode pad 111. As a result, the bending stress transmitted to the electrode pad 111 can be reduced. The warp of the substrate portion 110a is likely to occur in the longitudinal direction. On the other hand, the force due to the difference in thermal expansion between the temperature sensitive element 130 and the substrate portion 110a tends to increase in the longitudinal direction of the temperature sensitive element 130. Therefore, since the longitudinal direction of the temperature sensitive element 130 is different from the longitudinal direction of the substrate portion 110a in which the substrate portion 110a is likely to warp, the thermal expansion difference between the temperature sensitive element 130 and the substrate portion 110a is caused. Probability that the warp of the substrate portion 110a becomes large is reduced.

Further, in the present embodiment, the crystal unit 1 further includes an insulating resin 135 that is in close contact with the temperature sensitive element 130 and the lower surface of the substrate 110a.

In this case, for example, the resin portion 135 reinforces the substrate portion 110a against warpage. From another point of view, the stress caused by the force acting from the external terminal 113 to the second frame portion 110c is dispersed in the resin 135 located in the second recess K2. Therefore, the effect of reducing the difference in hysteresis characteristics before and after mounting is improved. Unlike the substrate portion 110a, the resin 135 is located not only between the temperature sensitive element 130 and the crystal element 120 but also on the side surface of the temperature sensitive element 130, etc., so that the resin portion 135 is thicker than the substrate portion 110a. The probability that the temperature difference between the temperature sensitive element 130 and the crystal element 120 is different is reduced.

Further, in the present embodiment, the electronic device 190 is located on the surface of the crystal unit 1 as described above, the base body (insulating substrate 181), and the insulating substrate 181, and is bonded to the plurality of external terminals 113. A plurality of external pads 182 that are present.

In such an electronic device 190, since the hysteresis characteristic after mounting the crystal unit 1 is reduced, it is possible to obtain the oscillation signal in which the fluctuation of the frequency due to the temperature change is reduced. As a result, for example, the operation of the electronic device 190 is stabilized, the accuracy of the operation is improved, and the probability of malfunction is reduced.

[Modification]
FIG. 4 is a bottom view of the crystal resonator 1-1 according to the modification, and corresponds to FIG. 3.

As shown in this figure, the centroid of the second recess K2 may be located on the opposite side (+D1 side) to the electrode pad 111 with respect to the centroid of the substrate 110a. In this case, the distance between the centroids in the D1 direction may be set appropriately. For example, the separation distance may be 1/30 or more or 1/20 or more of the length of the long side of the substrate 110a. Further, the separation distance may be shorter than, equal to, or longer than the distance s1 from the outer edge of the second frame portion 110c of the external terminal 113, for example, 1/2 or more of the distance s1 or It may be more than 1 time.

When the center of the second recess K2 is located on the opposite side of the center of the substrate 110a from the electrode pad 111 in this way, for example, the overlap between the electrode pad 111 and the second recess K2 can be reduced, It is possible to eliminate the overlap. As a result, for example, it is possible to secure the thickness of the insulating base 110 immediately below the electrode pad 111 and reduce the flexural deformation of the insulating base 110 directly below the electrode pad 111. As a result, it is possible to reduce the difference between the hysteresis characteristics before and after mounting due to the flexural deformation.

[Second Embodiment]
FIG. 5 is a bottom view of the crystal resonator 201 according to the second embodiment and corresponds to FIG.

In the crystal unit 201, the second recess K2 has a shape with the longitudinal direction of the substrate 110a as the longitudinal direction. The pair of connection pads 115 are arranged in the longitudinal direction of the substrate section 110a. The temperature sensitive element 130 is mounted on the pair of connection pads 115 with the longitudinal direction of the substrate 110a as the longitudinal direction.

Even in such a configuration, the effect of reducing the difference in the hysteresis characteristics before and after mounting, and by extension, reducing the hysteresis characteristics, is obtained by making the substrate section 110a an appropriate thickness. When the second recess K2 and the substrate 110a are aligned in the longitudinal direction, it is easy to secure the width of the second frame 110c over the entire circumference of the second frame 110c. The strength can be improved as a whole.

[Third Embodiment]
FIG. 6 is an exploded perspective view of the crystal unit 301 according to the third embodiment. FIG. 7 is a sectional view taken along line VIII-VII of FIG.

The crystal unit 301 realizes, for example, an H-type package in cross section, like the crystal unit 1 of the first embodiment. However, in the present embodiment, the member corresponding to the second frame portion 110c of the first embodiment is not the member integrally formed with the substrate portion 310a but the wiring board 360 on which the substrate portion 310a is mounted. .. Specifically, it is as follows.

The crystal unit 301 has a crystal unit 302 without a temperature-sensitive component and a wiring board 360 on which the crystal unit 302 is mounted. The crystal unit 302 has a container-shaped element mounting member 300 in which the first recess K1 is formed. The wiring board 360 has an opening 361. The crystal unit 302 is mounted on the wiring substrate 360 so that the lower surface thereof closes the opening 361. As a result, the lower surface of the crystal unit 302 and the inner peripheral surface of the opening 361 form the second recess K2. From another viewpoint, an H-type package is realized by the package of the crystal unit 302 and the wiring board 360. The temperature sensitive element 130 is mounted on a region of the lower surface of the crystal unit 302 exposed to the opening 361. As a result, the crystal unit 301 is a crystal unit with a temperature-sensitive component.

The insulating base 310 of the element mounting member 300 has a configuration in which the second frame portion 110c is removed from the insulating base 110 of the first embodiment. That is, the insulating base 310 has a substrate portion 310a and a first frame portion 310b. A plurality of (for example, four) mounting terminals 318 (FIG. 7) for mounting the element mounting member 300 on the wiring board 360 are provided on the lower surface of the board portion 310a.

The four mounting terminals 318 are located, for example, at the four corners of the lower surface of the substrate portion 310a. Two of the four mounting terminals 318 are electrically connected to the pair of electrode pads 111 via wiring conductors (not shown) provided on the insulating base 310. The other two of the four mounting terminals 318 are electrically connected to the pair of connection pads 115 via a wiring conductor (not shown) provided on the insulating base 310.

The wiring board 360 may have the same configuration as a rigid printed wiring board, for example. The wiring board 360 includes an insulating substrate 362 and various conductors (for example, metals) provided on the insulating substrate 362. The various conductors include, for example, a plurality of (four in the present embodiment) mounting pads 363 for mounting the crystal unit 302 on the wiring board 360, the wiring board 360 (the crystal unit 301) on the circuit board 180 (FIG. 2). A plurality of (four in the present embodiment) external terminals 113 to be mounted, and wiring conductors (not shown) that connect the plurality of mounting pads 363 and the plurality of external terminals 113. Although not shown in particular, the wiring substrate 360 may have a solder resist that covers the insulating substrate 362 while exposing the external terminals 113 and the mounting pads 363.

The plurality of mounting terminals 318 of the crystal unit 302 and the plurality of mounting pads 363 of the wiring board 360 are arranged so as to face each other, and are bonded by a bonding material 365 interposed therebetween. Thus, two of the four external terminals 113 are electrically connected to the pair of electrode pads 111. The other two of the four external terminals 113 are electrically connected to the pair of connection pads 115. The bonding material 365 is made of solder or the like.

A gap having a total thickness of the mounting terminals 318, the bonding material 365, and the mounting pads 363 is formed between the lower surface of the board portion 110a and the upper surface of the wiring board 360. In this gap, a gas may be allowed to flow from the second concave portion K2 to the outside of the side surface of the crystal unit 301 or in the opposite direction. The flow of may be prohibited. The filling height of the resin 135 with respect to the second recess and/or the temperature sensitive element 130 may be appropriately set as described in the first embodiment.

The outer edge of the insulating substrate 362 of the wiring board 360 may be located inside, substantially coincident with, or outside the outer edge of the board portion 110a (illustrated). Example). When the outer edge of the insulating substrate 362 is substantially aligned with the outer edge of the substrate 110a, for example, the mounting terminals 318, the mounting pads 363, and the external terminals 113 are substantially the same in shape and size. Further, for example, when the outer edge of the insulating substrate 362 is located outside the outer edge of the substrate portion 110a, for example, the shapes and sizes of the mounting terminal 318, the mounting pad 363, and the external terminal 113 are approximately the same as above. The external terminals 113 may have the same area, may have a larger area than the mounting pads 363 and the mounting terminals 318, and/or may be located outside the mounting pads 363 and the mounting terminals 318. The mounting terminal 318 may have a larger area and/or may be located outside.

The bottom view of the crystal unit 301 is the same as FIG. 3 of the first embodiment. Therefore, FIG. 3 may be incorporated as a bottom view of the crystal resonator 301 by replacing the reference numerals and the like of the second frame portion 110c with the reference numerals and the like of the wiring board 360. The description of the relative position and size of the external terminal 113 with respect to the outer edge of the second frame portion 110c (substrate portion 110a) or the region formed by the outer edge may also be incorporated in the present embodiment.

In the first embodiment, the outer edge of the substrate portion 110a and the outer edge of the second frame portion 110c substantially match. Therefore, for example, the relative position and size of the external terminal 113 or the second recess K2 with respect to the outer edge of the substrate portion 110a or the area formed by the outer edge, and the outer terminal 113 with respect to the outer edge of the second frame portion 110c or the area formed by the outer edge. Alternatively, the description has been made without distinction from the relative position and size of the second recess K2.

In the present embodiment, the description of the relative position and size of the external terminal 113 or the second recess K2 in the first embodiment is made, for example, with respect to the outer edge of the insulating substrate 362 of the wiring board 360 or the area formed by the outer edge. It may be applied to the relative position and size of the terminal 113 or the second recess K2. For example, the distance s1 and the area ratio S2/S1 may be specified based on the outer edge of the insulating substrate 362.

In addition, regarding the relative position and size of the external terminal 113 or the second recess K2 in the first embodiment, the relative position of the external terminal 113 or the second recess K2 with respect to the outer edge of the substrate portion 310a or a region formed by the outer edge is described. It may be applied to a specific position and size. For example, the condition that the distance s1 is 30 μm or more and 90 μm or less is satisfied with respect to the outer edge of the insulating substrate 362 as well as with the outer edge of the substrate portion 310a.

In addition, in the first embodiment, when the outer edge of the substrate portion 110a and the outer edge of the second frame portion 110c do not match, for example, the conditions such as the distance s1 and the area ratio are the same as in the present embodiment. The outer edge of the second frame portion 110c may be applied as a reference. In addition, it may be applied to the substrate part 110a.

The mounting terminal 318 of the crystal unit 302 may be in contact with or apart from the outer edge of the substrate unit 310a. When the external terminals 113 are separated from each other, the relative position and size of the external terminal 113 with respect to the outer edge of the substrate portion 110a (second frame portion 110c) or a region formed by the outer edge in the first embodiment is described in the outer edge of the substrate portion 310a. Alternatively, it may or may not be incorporated in the description of the relative position and size of the mounting terminal 318 with respect to the region formed by the outer edge. The planar shape of the mounting terminal 318 may be an appropriate shape. For example, similar to the external terminal 113 shown in FIG. 3, a rectangular shape having four sides parallel to the four sides of the substrate section 310a is changed to the second recess K2. The shape may be such that a part of the side is removed.

The mounting pad 363 of the wiring board 360 may be in contact with or apart from the outer edge of the insulating substrate 362 of the wiring board 360. In the case where they are separated from each other, the description of the relative position and size of the external terminal 113 with respect to the outer edge of the second frame portion 110c or the area formed by the outer edge in the first embodiment is made by the outer edge of the insulating substrate 362 or the outer edge. It may or may not be incorporated into the description of the position and size of the mounting pad 363 relative to the region. The planar shape of the mounting pad 363 may be an appropriate shape. For example, similar to the external terminal 113 shown in FIG. 3, a rectangular shape having four sides parallel to the four sides of the insulating substrate 362 is changed to a second concave portion K2. The shape may be such that a part of the side is removed.

As described above, in the present embodiment, the crystal unit 1 includes the substrate (the substrate portion 310a), the frame body (the insulating substrate 362 of the wiring substrate 360), the electrode pads 111, the connection pads 115, and the plurality of external terminals. 113, a piezoelectric element (quartz element 120), a temperature-sensitive component (temperature-sensitive element 130), and a lid 140. The substrate portion 310a has a rectangular shape. The insulating substrate 362 includes a pair of portions (short side portions) located in a region of the lower surface of the substrate portion 310a on the side of the pair of short sides of the substrate portion 310a. A recess (second recess K2) is formed therebetween. The electrode pad 111 is located on the upper surface of the substrate portion 310a. The connection pad 115 is located on the lower surface of the substrate portion 310a within the frame-shaped insulating substrate 362. The plurality of external terminals 113 are located on the lower surface of the insulating substrate 362. The crystal element 120 is mounted on the electrode pad 111. The temperature sensitive element 130 is mounted on the connection pad 115. The lid 140 hermetically seals the crystal element 120. The thickness of the substrate portion 310a in the vertical direction is 80 μm or more and 150 μm or less.

Therefore, the same effect as that of the first embodiment is achieved. Specifically, for example, since the thickness of the substrate portion 310a is 80 μm or more, the bending stress transmitted to the crystal element 120 is reduced. As a result, the difference between the hysteresis characteristics of the crystal unit 301 before and after mounting is reduced. In addition, since the thickness of the substrate portion 110a is 150 μm or less, for example, as compared with the case where the substrate portion 110a is thicker, the crystal element 120 and the temperature sensitive element 130 separated from each other by the substrate portion 110a. The probability of temperature deviations is reduced. As a result, the accuracy of temperature compensation is improved.

Further, in the present embodiment, the crystal unit 301 includes the mounting terminal 318 located on the lower surface of the substrate portion 310 a, the mounting pad 363 located on the upper surface of the insulating substrate 362 of the wiring board 360, and the mounting terminal 318. And a conductive bonding material 365 for bonding the mounting pad 363 to the mounting pad 363.

In this case, for example, as compared with the first embodiment, the warp and/or bending stress of the insulating substrate 362 is not directly transmitted to the substrate portion 310a. For example, the insulating substrate 362 is arranged along the substrate portion 310a, or the resin 135 filled in the gap between the substrate portion 310a and the insulating substrate 362 functions as a buffer material that relieves stress. Although it depends on the dimensions and the thermal expansion coefficient of the crystal unit 302, the wiring board 360, and the circuit board 180, the bending stress generated in the board portion 310a is reduced more than in the first embodiment depending on the mode of stress distribution.

[Example]
Crystal oscillators according to examples having different dimensions were produced and their characteristics were measured. As a result, it was confirmed that the hysteresis characteristic can be reduced by increasing the thickness of the substrate (the substrate portion 110a or the substrate portion 310a). Specifically, it is as follows.

The configuration of the crystal unit according to the example is that of the first embodiment. That is, the frame body is configured to include the second frame portion 110c integrally formed with the substrate portion 110a. In addition, the longitudinal direction of the second recess K2 and the temperature sensitive element 130 is the lateral direction of the element mounting member 100.

The main design conditions of the crystal unit according to the example are as follows.
Crystal piece 121: AT cut Crystal piece 121 thickness: 43 μm
Long side length of the substrate 110a: 1.6 mm
Short side length of the substrate part 110a: 1.2 mm
Thickness of the substrate part 110a: set in the range of 50 μm or more and 170 μm or less, every 10 μm.
Thickness of the second frame portion 110c: 230 μm
Thickness from the lower surface of the second frame portion 110c to the upper surface of the first frame portion 110b: 525 μm
Material of insulating base 110: Alumina ceramics

FIG. 8 is a conceptual diagram for explaining a normalized frequency difference ΔF/F which is an evaluation item for the crystal unit according to the example.

In this figure, the horizontal axis indicates the temperature T (°C). The vertical axis on the left side is the normalized frequency difference obtained by dividing the difference dF (Hz) between the design frequency F (Hz) of the oscillation signal and the actually measured frequency in the crystal unit by the design frequency F. It shows dF/F. The line Ln1 shows an example of the correspondence relationship between the temperature T and the frequency difference dF/F when the temperature rises. The line Ln2 shows an example of the correspondence relationship between the temperature T and the frequency difference dF/F when the temperature decreases.

As can be seen from this figure, the actual frequency changes due to temperature changes. The crystal unit is configured such that the frequency difference dF/F approaches 0 at a predetermined reference temperature T0, for example. The reference temperature T0 is set, for example, within a so-called normal temperature range (for example, 5° C. or higher and 35° C. or lower). Each of the lines Ln1 and Ln2 can be approximated by a cubic function. The temperature compensation circuit described above has coefficients and constants of an equation that specifies the correspondence relationship between the temperature T and the frequency difference dF (or the correction amount of the capacitance or the like corresponding to the dF), or map data. Then, the frequency of the oscillation signal is corrected based on the frequency difference dF corresponding to the temperature detected by the temperature sensitive element 130.

As can be understood from the comparison between the lines Ln1 and Ln2, the correspondence relationship between the temperature T and the frequency difference dF/F is different between when the temperature rises and when the temperature falls. This characteristic is the hysteresis characteristic already described. The difference between the dF/F when the temperature rises and the dF/F when the temperature falls corresponding to the same temperature is defined as a frequency difference ΔF/F. In FIG. 8, the vertical axis on the right side shows the frequency difference ΔF/F. The line Ln3 shows the correspondence between the temperature T and the frequency difference ΔF/F. The frequency difference ΔF/F changes with respect to the temperature T. In FIG. 8, ΔF/F is exaggerated more than it actually is.

The lines Ln1 and Ln2 measure the frequency of the oscillation signal while increasing the temperature from the lower limit side to the upper limit side of the illustrated range, or decreasing the temperature from the upper limit side to the lower limit side of the illustrated range, for example. Obtained by However, the crystal oscillator actually used is exposed to more complicated temperature changes (temperature history). Therefore, the temperature compensation amount is not separately defined for the temperature rise and the temperature fall based on the lines Ln1 and Ln2, respectively, and the temperature compensation amount for the same temperature is the temperature rise and the temperature fall. It is the same as time. Therefore, if the frequency difference ΔF/F is reduced, the temperature compensation accuracy improves, for example.

FIG. 9 is a diagram showing the hysteresis characteristic of the crystal unit mounted on the circuit board 180. In these figures, the horizontal axis represents the temperature T (°C). The vertical axis represents the normalized frequency difference ΔF/F (ppb: parts per billion) described with reference to FIG. 8. A plurality of lines in the drawing show the correspondence relationship between the temperature T and the frequency difference ΔF/F in a plurality of examples in which the thickness of the substrate portion 110a is different from each other. On the right side of the drawing, the correspondence between the line type and the thickness t1 (μm) of the substrate 110a is shown. On the right side thereof, a value t1/L1 obtained by dividing the thickness t1 of the board portion 110a by the length L1 of the long side of the board portion 110a and the thickness t1 of the board portion 110a to the thickness t2 of the mounting substrate 110 ( A value t1/t2 divided by the thickness from the lower surface of the second frame portion 110c to the upper surface of the first frame portion 110b) is added. Although not particularly shown, ΔF/F of the crystal unit before being mounted on the circuit board 180 is generally within the range of 0±50 (ppb).

As shown in this figure, the greater the thickness t1 of the substrate portion 110a, the smaller the frequency difference ΔF/F. Particularly, when the thickness t1 of the substrate portion 110a is 80 μm or more (s1/L1 is 0.050 or more), the substrate 110a is thinner than this over the entire temperature range (−30° C. to 90° C.) illustrated. There is a significant difference from the case.

In the above embodiments, the crystal resonators 1, 1-1, 201 and 301 are examples of piezoelectric devices. The substrate parts 110a and 310a are examples of substrates. The second recess K2 is an example of a recess. The second frame portion 110c and the wiring board 360 are each an example of a frame body. The crystal element 120 is an example of a piezoelectric element. The temperature sensitive element 130 is an example of a temperature sensitive component.

The technology according to the present disclosure is not limited to the above embodiments and modifications, and may be implemented in various aspects.

The above-described embodiments and modifications may be combined as appropriate. For example, the electrode pad (111) is provided with respect to the centroid of the recessed portion (second recessed portion K2) shown in FIG. 4 formed by the outer edge of the substrate (substrate portion 110a) or the frame body (second frame portion 110c). The configuration located on the side opposite to may be applied to the second or third embodiment. The configuration shown in FIG. 5 in which the longitudinal direction of the recess and the temperature-sensitive component (temperature-sensitive element 130) is the longitudinal direction of the substrate or the frame body may be applied to the third embodiment.

The piezoelectric element is not limited to the vibration element used for the vibrator. For example, the piezoelectric element may be an acoustic wave element such as a SAW (surface acoustic wave) element, or a vibration element of a piezoelectric vibration type gyro sensor. From another viewpoint, the piezoelectric device is not limited to a device that generates an oscillation signal such as a vibrator or an oscillator, and may be a device that filters a signal like an acoustic wave device or a physical quantity like a gyro sensor. It may be a sensor for detecting.

The piezoelectric body used for the piezoelectric element is not limited to quartz and from another viewpoint, is not limited to single crystal. For example, the piezoelectric body may be ceramic (polycrystal), lithium tantalate single crystal, or lithium niobate single crystal.

The temperature-sensitive component is not limited to a temperature sensor (temperature-sensitive element, transducer) in a narrow sense. For example, the temperature-sensitive component may have a function of processing an electric signal whose temperature has been converted. The processing includes, for example, amplification, modulation, filtering, and calculation based on the detected temperature. In other words, the temperature-sensitive component may be an integrated circuit element (IC: Integrated Circuit) including a temperature-sensitive element.

In the case where the piezoelectric element is a vibrating element used for a vibrator, the IC as the temperature-sensitive component is an oscillation circuit that applies a voltage to the vibrating element to generate an oscillation signal and a temperature detected by the temperature-sensitive element. And a compensating circuit for temperature compensating the frequency characteristic of the vibrating element. That is, the piezoelectric device may be a temperature compensation oscillator.

When the IC as the temperature-sensitive component has an oscillation circuit and a compensation circuit, for example, the vibration element and the IC are connected, and the IC and the external terminal of the wiring board are connected. In other words, the vibration element and the external terminal are not directly connected. The electric signal output from the terminal of the IC (the terminal of the temperature-sensitive component) to the external terminal is, for example, an oscillation signal, and is not a signal including temperature information. As can be seen from this example, the temperature-sensitive component may be utilized inside the temperature-sensitive component without outputting the temperature-generated electrical signal to the connection pad.

In the embodiment, the first frame portion 110b is provided on the substrate (the substrate portion 110a), and the plate-shaped lid body is covered thereon. However, the first frame 110b may not be provided, and a box-shaped lid whose bottom is opened may be joined to the upper surface of the substrate to seal the piezoelectric element.

In the embodiment, the frame body (the second frame portion 110c and the wiring board 360) has an annular shape extending along the entire circumference of the board. However, the frame does not have to be annular. For example, the frame body may have a pair of portions extending along the pair of short sides of the substrate, and may not have a portion extending along the pair of long sides of the substrate.

The external terminals may be provided in a number greater than four. For example, five or more external terminals may be arranged along the outer edge of the lower surface of the package. Similarly, other terminals or pads such as external pads and connection pads may be provided in numbers other than those shown.

The minimum rectangular area R1 including a plurality of external terminals may match the rectangular area formed by the outer edge of the lower surface of the frame body. Further, when they do not match, all of the plurality of external terminals may not be separated from the outer edge of the lower surface of the frame body. Further, the entire external terminals may not be separated from the outer edge of the lower surface of the frame body. For example, each of the external terminals at the four corners may be separated only from the long side adjacent to itself, or may be separated only from the short side adjacent to itself.

DESCRIPTION OF SYMBOLS 1... Crystal oscillator (piezoelectric device), 110a... Substrate part (substrate), 110c... 2nd frame part (frame body), 111... Electrode pad, 113... External terminal, 115... Connection pad, 120... Crystal element (piezoelectric) Element), 130... Temperature-sensitive element (temperature-sensitive component), 140... Lid, K2... Second recess (recess).

Claims (10)

A rectangular substrate,
A frame body that includes a pair of portions located in a region of a pair of short sides of the substrate on the lower surface of the substrate, and that forms a recess between the pair of portions;
An electrode pad located on the upper surface of the substrate,
A connection pad located on the lower surface of the substrate in the frame;
A plurality of external terminals located on the lower surface of the frame,
A piezoelectric element mounted on the electrode pad,
A temperature-sensitive component mounted on the connection pad,
A lid that hermetically seals the piezoelectric element,
Has
A piezoelectric device in which the substrate has a vertical thickness of 80 μm or more and 150 μm or less. The piezoelectric device according to claim 1, wherein a value obtained by dividing the thickness of the substrate in the vertical direction by the length of the long side of the substrate is 0.050 or more and 0.094 or less. The piezoelectric device according to claim 1, wherein the entire electrode pad is located outside the recess when seen in a plan view. The piezoelectric device according to any one of claims 1 to 3, wherein the concave portion and the temperature-sensitive component have a shape in which a pair of long sides of the substrate are opposed to each other in a longitudinal direction. The piezoelectric device according to any one of claims 1 to 4, wherein the centroid of the recess is located on the opposite side of the centroid of the substrate from the electrode pad when seen in a plan view. The piezoelectric device according to claim 1, wherein the substrate and the frame are directly bonded to each other. Mounting terminals located on the lower surface of the substrate,
A mounting pad located on the upper surface of the frame,
A conductive bonding material that bonds the mounting terminal and the mounting pad,
The piezoelectric device according to claim 1, further comprising: The piezoelectric device according to claim 1, further comprising an insulating resin that covers the temperature-sensitive component and is in close contact with the lower surface of the substrate. The piezoelectric device according to claim 8, wherein the resin is also located in a gap between the lower surface of the substrate and the upper surface of the frame body. A piezoelectric device according to any one of claims 1 to 9,
A substrate,
A plurality of external pads that are located on the surface of the base and are joined to the plurality of external terminals;
An electronic device having.

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