JP7083303B2 - Piezoelectric devices and electronic devices - Google Patents

Description

The present disclosure relates to a piezoelectric device and an electronic device including the piezoelectric device. Piezoelectric devices are, for example, crystal oscillators and crystal oscillators.

As a piezoelectric device, a device having a so-called H-shaped package is known (for example, Patent Document 1). The H-shaped 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 vibration element is mounted in a region of the upper surface of the substrate surrounded by the first frame portion. A thermistor or an IC (Integrated Circuit) is mounted on the area of the lower surface of the substrate surrounded by the second frame portion. 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, a configuration in which a pseudo H-shaped package is realized by using a wiring board is also known (for example, Patent Document 2). In this configuration, a container-type package is used as a portion corresponding to the above-mentioned substrate and the first frame portion. A wiring board having an opening is used as a portion corresponding to the second frame portion. By mounting the container-type package on the upper surface of the wiring board so as to cover the opening, the H-type package is formed in a pseudo manner. External terminals are provided on the lower surface of the wiring board as in the second frame portion. In Patent Document 2, the external terminal is separated from the outer edge of the wiring board.

Crystal oscillators and crystal oscillators are known to exhibit so-called hysteresis characteristics. That is, when the oscillation frequency changes due to the temperature change, the oscillation frequency (error from another viewpoint) differs between the time when the temperature rises and the time 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).

Japanese Unexamined Patent Publication No. 2000-49560 Japanese Unexamined Patent Publication No. 2016-082538 Japanese Unexamined Patent Publication No. 2010-087715

For example, it is desired to provide piezoelectric devices and electronic devices capable of reducing fluctuations in characteristics such as hysteresis characteristics.

The piezoelectric device according to one aspect of the present disclosure includes a rectangular substrate and a pair of portions of the lower surface of the substrate located in a region on the short side of the substrate. 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 surface, a piezoelectric element mounted on the electrode pad, a temperature-sensitive component mounted on the connection pad, and a lid for airtightly sealing the piezoelectric element. The ratio S2 / S1 of the area S1 of the rectangular area formed by the outer edge of the lower surface of the frame and the area S2 of the smallest rectangular area including all the external terminals is 0.75 or more. It is 0.91 or less.

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

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

In one example, in planar fluoroscopy, the entire electrode pad is located outside the recess.

In one example, the recess and the temperature-sensitive component have a shape in which the opposite direction of a pair of long sides of the substrate is the longitudinal direction.

In one example, in planar fluoroscopy, the centroid of the recess is located on the side opposite to the electrode pad with respect to the centroid of the substrate.

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

The electronic device according to one aspect of the present disclosure includes the piezoelectric device, a substrate, and a plurality of external pads located on the surface of the substrate and bonded to the plurality of external terminals. ..

According to the above configuration, fluctuations in characteristics can be reduced.

It is an exploded perspective view which shows the structure of the crystal oscillator which concerns on 1st Embodiment. FIG. 3 is a cross-sectional view taken along the line II-II of FIG. It is a bottom view of the crystal oscillator of FIG. It is a bottom view of the crystal oscillator which concerns on a modification. It is a bottom view of the crystal oscillator which concerns on 2nd Embodiment. It is an exploded perspective view which shows the structure of the crystal oscillator which concerns on 3rd Embodiment. 6 is a cross-sectional view taken along the line VII-VII of FIG. 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. For convenience, the drawings may include an orthogonal coordinate system consisting of the D1 axis, the D2 axis, and the D3 axis. The crystal oscillator according to the embodiment may be used in any direction as upward or downward. However, in the following, for convenience, terms such as upper surface or lower surface may be used with the + D3 side facing upward. Further, in the following description, the term "planar 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 specifically mentioned may be the same as those described above. Further, even if there are differences in the configurations corresponding to each other among the plurality of embodiments, the same reference numerals may be given for convenience of explanation.

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

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

As shown in FIG. 1, the crystal oscillator 1 is mounted on the element mounting member 100, the crystal element 120 mounted on the element mounting member 100 from the upper surface side, and 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 the package of the crystal oscillator 1. As shown in FIG. 2, the temperature sensing element 130 is at least partially covered with the resin 135.

(Element mounting member)
The element mounting member 100 has an insulating substrate 110 and various conductors located on the surface and / or inside the insulating substrate 110. For various conductors, for example, a pair of electrode pads 111 for mounting the crystal element 120, a pair of connection pads 115 for mounting the temperature sensitive element 130, and a crystal oscillator 1 are mounted on the circuit board 180. There are four external terminals 113 for the purpose.

The pair of electrode pads 111 are electrically connected to two of the four external terminals 113 by a wiring conductor included in 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 a wiring conductor included in the element mounting member 100. As a result, 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, the wiring conductor may be appropriately configured by a layered conductor and / or a via conductor located on the surface and / or inside of the element mounting member 100. FIG. 3 shows two wiring patterns 116 that form part of a wiring conductor that connects the two connection pads 115 and the two external terminals 113.

(Insulated substrate)
The insulating substrate 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. The first recess K1 is formed by the upper surface of the substrate portion 110a and the inner peripheral surface of the first frame portion 110b. The second recess K2 is formed by the inner peripheral surface of the lower surface of the substrate portion 110a and the second frame portion 110c. The first recess K1 is hermetically sealed by a lid 140. The insulating substrate 110 has an H-shaped cross section, which constitutes a so-called H-shaped package.

The substrate portion 110a is roughly a plate shape having a constant thickness. Its planar shape is rectangular. The planar shape of the substrate portion 110a is more specifically rectangular, 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. The lower limit and the upper limit may be appropriately combined as long as they do not contradict each other.

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

The first frame portion 110b and the second frame portion 110c each have 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. Further, the thickness of the second frame portion 110c may be thinner, equal to, 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 thinner than the thickness of the first frame portion 110b and the second frame portion 110c.

In the first frame portion 110b (first recess K1), the shape (planar shape) of the cross section orthogonal to the D3 axis and the dimensions in the cross section are the substrate portion 110a side (-D3 side) and the opposite side (+ D3 side). Is 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 dimensions in the cross section are the substrate portion 110a side (+ D3 side) and the opposite side (-D3). It is almost the same as the side). However, unlike the illustrated example, in each of the first frame portion 110b and the second frame portion 110c, the planar shape and the dimensions thereof may be different between the substrate portion 110a side and the opposite side thereof. In this case, the description of the planar shape 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, and any of them may be applied. It may be applied to either one.

In a plan view, the inner edge and the outer edge of the first frame portion 110b have a rectangular shape having four sides parallel to the four sides of the substrate portion 110a. From another point of view, 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 (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 as each other or may be different from each other.

The first recess K1 is, for example, relatively wide in plan view. As an example, the area of the first recess K1 is ½ or more or 2/3 or more of the area of the substrate portion 110a. From another viewpoint, 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 less than 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 portion 110a. To be confirmed, the center of the figure is the point where the first moment of the cross section with respect to the axis passing through the point becomes 0 in the planar shape. The distance between the center of the substrate portion 110a and the center 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 portion 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 portion 110c substantially coincides (overlaps) with the outer edge of the substrate portion 110a. From this, in the description below, 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 region formed by the outer edge, and the outer edge or the outer edge of the second frame portion 110c. It is not distinguished from the relative position and size of the external terminal 113 or the second recess K2 with respect to the area formed by the eggplant, and only one of them may be mentioned.

In a plan view, the shape of the inner edge (second recess K2) of the second frame portion 110c may be an appropriate shape such as a rectangular shape, a circular shape, an elliptical shape, or a polygonal shape other than the 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 portion 110a and a long side parallel to the short side of the substrate portion 110a, and the corner portion is chamfered relatively large. 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 longitudinal direction and the longitudinal direction of the substrate portion 110a is the longitudinal direction.

In a plan view, the area of the second recess K2 is, for example, smaller than the area of the first recess K1. As an example, the area of the second recess K2 is 4/5 or less or 3/4 or less with respect to the area of the substrate portion 110a and / or the first recess K1. From another viewpoint, the width of the short side of the second frame portion 110c is, for example, 1/4 or more or 1/3 or more of the length of the long side of the substrate portion 110a.

In a plan view, the second recess K2 is located, for example, on the center side with respect to the substrate portion 110a. More specifically, for example, the centroid of the substrate portion 110a is located in the second recess K2. Further, the distance between the center of the substrate portion 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 portion 110a.

The substrate portion 110a, the first frame portion 110b, and the second frame portion 110c are made of a ceramic material such as, for example, alumina ceramics or glass-ceramics. The substrate portion 110a, the first frame portion 110b, and the second frame portion 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 use one insulating layer from the viewpoint of the material and / or the manufacturing method, or may have a plurality of insulating layers. It may be laminated.

The substrate portion 110a and the first frame portion 110b are integrally formed, for example. Further, the substrate portion 110a and the second frame portion 110c are integrally formed, for example. The integral formation is defined as, for example, that the insulating material constituting the substrate portion 110a and the insulating material constituting the first frame portion 110b (or the second frame portion 110c) are directly contacted and joined to each other. 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 laminating 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 a conductor layer interposed between the first recess K1, the second recess K2, and / or each portion.

(Electrode pad)
The pair of electrode pads 111 is composed of a conductor layer located on the upper surface of the substrate portion 110a. The material and thickness of the conductor layer may be appropriately set. The pair of electrode pads 111 are arranged, for example, in a direction along one short side of the substrate portion 110a, and are adjacent to the inner peripheral surface of the first frame portion 110b. The adjacency here is, for example, that the distance (D1 direction) of the first frame portion 110b from the inner peripheral surface 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 away from the first frame portion 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 made smaller than the first recess K1 in a plan view. From another viewpoint, the region of the upper surface of the substrate portion 110a surrounded by the first frame portion 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 is entirely located in a region of the substrate portion 110a that does not overlap with the second recess K2. Of course, unlike the illustrated example, the pair of electrode pads 111 may partially overlap with the second recess K2.

(Connection pad)
The connection pad 115 is composed of a conductor layer located on the lower surface of the substrate portion 110a. The material and thickness of the conductor layer may be appropriately set. The pair of connection pads 115 are arranged, for example, in the direction in which the long sides of the substrate portion 110a face each other (in the D2 direction; from another viewpoint, the longitudinal direction of the second recess K2) on the center side of the substrate portion 110a. 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 appropriately set. The four external terminals 113 are located, for example, on the four corners 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 of 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 portion 110c. The edge of the removed portion may be a straight line, a combination of two or more straight lines (illustrated example), or a curved line.

On the lower surface of the second frame portion 110c, the conductor layer constituting the external terminal 113 may have a portion other than the external terminal 113. In the example of FIG. 3, the conductor layer has a connecting portion 114 located between the external terminal 113 and the recess 110cc (castering) at the corner of the second frame portion 110c. The connecting portion 114 is connected to the casting conductor 117 (FIG. 1) formed in the recess 110cc. The connecting portion 114 and the casting 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 a function thereof. May be reasonably distinguished from. For example, in the planar shape of the conductor layer, the specifically protruding portion 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 portion 110c can be recognized. The connecting portion 114 protrudes from a part of the side 113a (for example, 1/4 or less of the length of one side 113a). For this reason, the external terminal 113 and the connection 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 external terminal 113 has two sides constituting one corner of the four sides 110ca of the outer edge of the second frame portion 110c on the side on which 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 point of view, the side 113a extends along (for example, in parallel) the side 110ca of the outer edge of the second frame portion 110c. The sides 113a and the sides 110ca facing each other are separated by a distance s1. The distance s1 may be the same on the two sides 113a of one external terminal 113 (example in the figure), or may be different. Further, the distance s1 may be the same among the four external terminals 113 (example in the figure), or may be different.

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

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

(Cover)
The lid 140 is made of, for example, an alloy containing at least one of iron, nickel or 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 thereof. As a result, the first recess K1 is sealed. The first recess K1 may be filled with gas or may be in a vacuum state. The gas is, for example, nitrogen. In reality, the vacuum is decompressed more than the 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 portion 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 is, for example, for connecting a crystal piece 121, a pair of excitation electrodes 122 for applying a voltage to the crystal piece 121, and a pair of connecting electrodes 120 for mounting the crystal element 120 on a pair of electrode pads 111. It has an electrode 123. The pair of excitation electrodes 122 and the pair of connecting 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 point of view, the crystal piece 121 has a shape having a longitudinal direction and a lateral direction. The crystal piece 121 is made of, for example, an AT-cut crystal piece. Although not particularly shown, the crystal piece 121 may be of various known materials other than the examples shown in the figure. For example, the crystal element may be a so-called tuning fork type. Further, when the crystal piece 121 is plate-shaped, it may be a so-called mesa type having a thick central portion, or a so-called convex type crystal piece becoming thinner as it approaches the outer edge. You may. 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 composed of a conductor layer that overlaps the surface of the crystal piece 15. The material and thickness of the conductor layer may be appropriately set. The pair of excitation electrodes 122 are located on the center side of a pair of main surfaces (front and back surfaces 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 the crystal piece 121 on one side (longitudinal direction) of the crystal piece 121 with respect to the pair of excitation electrodes 122. It is located on one of the short sides). Further, for example, the connection electrodes 123 are arranged along one short side of the crystal piece 121. The pair of extraction electrodes 124 connects the pair of excitation electrodes 122 and the pair of connection electrodes 123 by the shortest route. The specific shapes of the excitation electrode 122, the connection electrode 123, and the extraction electrode 124 may be appropriately set, and in the illustrated example, they are each rectangular.

(Mounting of crystal element)
As shown in FIG. 2, the crystal element 120 is mounted on the element mounting member 100 by joining the connection electrode 123 and the electrode pad 111 with a conductive adhesive 150. As described above, since the pair of connecting electrodes 123 are 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 supported. It is said to be a free end. The conductive adhesive 150 is composed of a resin mixed with a conductive filler. The resin is, for example, a thermosetting resin. The specific material of the resin and the conductive filler, the diameter of the conductive filler, and the like may be appropriately set.

(Temperature sensitive element)
The temperature sensitive element 130 is composed of, for example, an element whose electrical characteristics (for example, resistance value) change in response to a temperature change. Examples of such are thermistors, resistance temperature detectors and diodes. The temperature sensing element 130 is formed, for example, in a substantially rectangular parallelepiped shape, and has a pair of connection terminals 131 at both ends thereof. The connection terminal 131 is exposed to at least a surface facing the lower surface of the substrate portion 110a in the rectangular parallelepiped shape of the temperature sensitive element 130. In the illustrated example, the connection terminal 131 is formed over five surfaces, an upper and lower surface, a side surface, and an end surface, at each end portion in the longitudinal direction of the rectangular parallelepiped.

The pair of connection terminals 131 faces the pair of connection pads 115 and are joined by a joining material 133 interposed between them. The joining material 133 is composed of solder or a conductive adhesive.

(resin)
The resin 135 is made of, for example, a thermosetting resin (for example, an epoxy resin). The resin 135 may contain a filler. Examples of the filler include those having a lower coefficient of thermal expansion than that of a resin (for example, SiO ₂ ). In addition, for example, a filler having a lower or higher thermal conductivity than the resin may be added for adjusting the thermal conductivity.

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

Specifically, for example, the surface of the resin 135 on the side opposite to the substrate portion 110a (-D3 side) may be located above (+ D3 side) the surface on the -D3 side of the temperature sensitive element 130. However, it may be located on the surface on the −D3 side of the temperature sensitive element 130 (example in the figure), or may be located below the surface on the −D3 side of the temperature sensitive element 130. In other words, the resin 135 may be in close contact with a part of the + D3 side of the side surface of the temperature sensitive element 130 (at least one side surface, for example, all (four) side surfaces; the same applies hereinafter). , It may be in close contact with all the side surfaces of the temperature sensitive element 130 (example in the figure), or may be in close contact with the surface of the temperature sensitive element 130 on the −D3 side in addition to the side surface of the temperature sensitive element 130 (the example shown in the figure). 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 constituting the second recess K2, or may be in close contact with the entire lower surface of the substrate portion 110a and the second frame. Of the inner peripheral surfaces of the portion 110c (at least one surface, for example, all (six) surfaces; the same applies hereinafter), only a part of the substrate portion 110a side may be in close contact with the inner peripheral surface (illustrated example). , The lower surface of the substrate portion 110a and the upper and lower surfaces of the inner peripheral surface of the second frame portion 110c may be in close contact with each other.

(Circuit board)
The circuit board 180 shown in FIG. 2 is composed of, for example, a known rigid substrate or flexible substrate, and has an insulating substrate 181 and an external pad 182 located on the upper surface of the insulating substrate 181. The external terminal 113 of the crystal oscillator 1 is bonded to the external pad 182 by a bonding material 183 such as solder. The joining material 183 may be joined over the entire or most (for example, an area of 80% or more) of the lower surface of the external terminal 113 and / or the upper surface of the external pad 182, and may not be a majority. It may be joined to.

The electronic device 190 has, for example, an oscillation circuit and a temperature compensation circuit composed of an IC mounted on the circuit board 180 and / or the circuit board 180, although not particularly shown. The oscillation circuit applies an AC voltage to the crystal element 120 via two of the four external terminals 113 to generate an oscillation signal having a predetermined frequency. The temperature compensation circuit compensates for changes in the frequency characteristics of the crystal oscillator 1 due to temperature changes. 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 via two of the four external terminals 113.

The electronic device 190 may be any device that utilizes 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 the dimensions of each part of the crystal oscillator 1 is 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 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 as long as they do not contradict each other. Further, the length of the short side of the substrate portion 110a may be 1.0 mm or more, 1.5 mm or more, or 2.0 mm or more, provided that the length of the short side of the substrate portion 110a is shorter than the length of the long side of the substrate portion 110a, for example. Further, it 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, it is assumed that the second decimal place value 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 portion 110a may be, for example, 50 μm or more or 80 μm or more, or 170 μm or less or 150 μm or less, and the above lower limit and upper limit may be appropriately combined. In this example, it is assumed that the first decimal place value is rounded off. Further, 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. It may be as follows, and the above lower limit and upper limit may be appropriately combined. In this example, it is assumed that 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 combined as appropriate. In this example, it is assumed that the first decimal place value is rounded off. Further, the value obtained by dividing the distance s1 by the length of the long side of the substrate portion 110a may be, for example, 0.013 or more or 0.038 or more, and 0.125 or less or 0.113 or less. Often, the lower and upper limits may be combined as appropriate. In this example, it is assumed that the fourth decimal place is rounded off.

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

(Manufacturing method of crystal oscillator)
As a method for manufacturing the crystal oscillator 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 serving as a substrate portion 110a, a first frame portion 110b, and a second frame portion 110c are prepared. The ceramic green sheet serving as the first frame portion 110b and the second frame portion 110c is formed with openings to be the first recess K1 and the second recess K2. Further, before or after the formation of the opening, a conductive paste serving as various conductors (external terminal 113, electrode pad 111, connection pad 115, etc.) is arranged on a plurality of ceramic green sheets. After that, a plurality of ceramic green sheets are laminated to form a laminated body, and the laminated body is fired.

Further, a method for manufacturing the element mounting member 100, which is different from the above method, can be mentioned. First, a plurality of ceramic green sheets serving as a substrate portion 110a, a first frame portion 110b, and a second frame portion 110c are prepared. Conductive pastes to be various conductors (external terminal 113, electrode pad 111, connection pad 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 recess K1 and the second recess K2 are formed by pressing the laminated body. Then, the laminate is fired.

As described above, in the present embodiment, the crystal oscillator 1 includes a substrate (board portion 110a), a frame body (second frame portion 110c), an electrode pad 111, a connection pad 115, and a 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 portion 110a has a rectangular shape. The second frame portion 110c includes a pair of portions (short side portions) located in a pair of short side regions of the substrate portion 110a in the lower surface of the substrate portion 110a, and the pair of the second frame portions 110c. A recess (second recess K2) is formed between the portions. The electrode pad 111 is located on the upper surface of the substrate portion 110a. The connection pad 115 is located on the lower surface of the substrate portion 110a in the second frame portion 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 airtightly seals the crystal element 120. The ratio S2 / S1 of the area S1 of the rectangular area formed by the outer edge of the lower surface of the second frame portion 110c to the area S2 of the smallest rectangular area R1 including all the external terminals 113 is 0.75 or more and 0.91 or less. Yes (third decimal place shall be rounded off).

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

The characteristics of the crystal oscillator 1 differ between before being mounted on the circuit board 180 and after being mounted on the circuit board 180. Examples of such characteristics include hysteresis characteristics. As described above, the hysteresis characteristic is a characteristic in which the frequency error caused by the temperature change differs between when the temperature rises and when the temperature falls, 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 oscillator 1 and the circuit board 180 is transmitted 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 as, for example, bending stress that tends to cause warpage (bending deformation) of the insulating substrate 110. This bending stress is transmitted to the crystal element 120 via each electrode pad 111 and / or a 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 between 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 smallest rectangular region R1 including the plurality of external terminals 113 is smaller than the rectangular region formed by the outer edge of the second frame portion 110c (the concave portion 110cc or the region ignoring the chamfering of the corner portion). .. From another point of view, the plurality of external terminals 113 are separated from the outer edge of the second frame portion 110c. Therefore, as compared with the case where the plurality of external terminals 113 are in contact with the outer edge of the second frame portion 110c, the positions where the force from the circuit board 180 acts on the plurality of external terminals 113 can be brought closer to each other. As a result, the force applied from the circuit board 180 to the element mounting member 100 via the plurality of external terminals 113 is less likely to act as bending stress that causes the substrate portion 110a to warp. As a result, the bending stress transmitted to the crystal element 120 is reduced. As a result, the difference in the hysteresis characteristic of the crystal oscillator 1 between before and after mounting is reduced.

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

Further, as described above, when the area ratio S2 / S1 is 0.91 or less, for example, when the area ratio S2 / S1 is 1, the difference between before and after mounting the hysteresis characteristic is significant. Differences are found. That is, the above-mentioned effect can be confirmed. Further, when the area ratio S2 / S1 is 0.75 or more, the external terminal 113 can be expanded to the outside while being separated from the outer edge of the second frame portion 110c, so that the external terminal 113 can be expanded to the outside. It is easy to secure an area. From another point of view, when a certain area is secured in the external terminal 113, the possibility that the plurality of external terminals 113 are short-circuited is reduced.

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 easily transmitted from the second frame portion 110c to the substrate portion 110a. Therefore, the effect of reducing the bending stress directly under the electrode pad 111 by making the area S2 smaller than the area S1 is likely to appear.

Further, in the present embodiment, the entire electrode pad 111 is located outside the recess (second recess K2) in planar fluoroscopy.

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 secured. Therefore, the warp of the insulating substrate 110 is reduced immediately below the electrode pad 111 as compared with the case where the electrode pad 111 overlaps the second recess K2. From another viewpoint, the bending stress is dispersed in the thickness direction of the insulating substrate 110 directly under the electrode pad 111. 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 between before and after mounting the hysteresis characteristic is improved. Further, for example, since the second frame portion 110c is widened so as to overlap the entire electrode pad 111, it is easy to secure the area of the external terminal 113 located on the lower surface of the second frame portion 110c. As a result, it becomes easy to reduce the area S2.

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

When trying to secure the area of the external terminal 113 to some extent while reducing the area S2, the area of the external terminal 113 is secured near the second recess K2. At this time, as can be understood from the comparison with the second embodiment (FIG. 5) described later, when the second concave portion K2 has the lateral direction of the substrate portion 110a as the longitudinal direction, the area of the external terminal 113 is set to the substrate portion. It is easy to secure it on the center side in the longitudinal direction of 110a. As a result, the force transmitted from the circuit board 180 to the substrate portion 110a via the plurality of external terminals 113 acts on the central side in the longitudinal direction of the substrate portion 110a, causing the substrate portion 110a to warp in the longitudinal direction of the substrate portion 110a. The moment to make it becomes smaller. Since the substrate portion 110a is likely to warp in the longitudinal direction, the warp of the substrate portion 110a as a whole is effectively reduced by reducing the moment that causes the warp in the longitudinal direction. Further, 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 and the longitudinal direction of the substrate portion 110a where the substrate portion 110a is likely to warp are different, the difference in thermal expansion between the temperature sensitive element 130 and the substrate portion 110a causes. The probability that the warp of the substrate portion 110a becomes large is reduced.

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

The position where the force from the circuit board 180 acts on the second frame portion 110c approaches the second recess K2 by reducing the area S2. As a result, for example, the stress caused by the force acting on the second frame portion 110c from the external terminal 113 is likely to be dispersed in the resin 135 located in the second recess K2. Therefore, the provision of the resin 135 improves the effect of reducing the difference between before and after mounting the hysteresis characteristic.

Further, in the present embodiment, the electronic device 190 is located on the surface of the crystal oscillator 1, the substrate (insulating substrate 181), and the insulating substrate 181 as described above, and is joined to a plurality of external terminals 113. It has a plurality of external pads 182 and the like.

In such an electronic device 190, since the hysteresis characteristic after mounting the crystal oscillator 1 is reduced, an oscillation signal in which frequency fluctuation due to a temperature change is reduced can be obtained. 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 example]
FIG. 4 is a bottom view of the crystal oscillator 1-1 according to the modified example, and corresponds to FIG.

As shown in this figure, the centroid of the second recess K2 may be located on the opposite side (+ D1 side) of the electrode pad 111 with respect to the centroid of the substrate portion 110a. In this case, the separation distance between the centroids in the D1 direction may be appropriately set. 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 portion 110a. Further, the separation distance may be shorter, equal to, or longer than the distance s1 from the outer edge of the second frame portion 110c of the external terminal 113, and may be, for example, ½ or more of the distance s1 or. It may be 1 times or more.

When the centroid of the second recess K2 is positioned on the side opposite to the electrode pad 111 with respect to the centroid of the substrate portion 110a 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, the thickness of the insulating substrate 110 can be secured directly under the electrode pad 111, and the bending deformation of the insulating substrate 110 directly under the electrode pad 111 can be reduced. As a result, it is possible to reduce the difference between before and after mounting the hysteresis characteristic due to this bending deformation.

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

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

Even in such a configuration, by making the area S2 smaller than the area S1, the effect of reducing the difference between before and after mounting the hysteresis characteristic and, by extension, reducing the hysteresis characteristic can be achieved. Further, when the longitudinal directions of the second recess K2 and the substrate portion 110a are the same, it is easy to secure the width of the second frame portion 110c over the entire circumference of the second frame portion 110c, so that the insulating substrate 110 It is easy to improve the strength evenly as a whole.

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

The crystal oscillator 301 realizes an H-shaped package in a cross section, for example, like the crystal oscillator 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 a member integrally formed with the substrate portion 310a, but is composed of a wiring board 360 on which the substrate portion 310a is mounted. .. Specifically, it is as follows.

The crystal oscillator 301 has a crystal oscillator 302 without a temperature-sensitive component and a wiring board 360 on which the crystal oscillator 302 is mounted. The crystal oscillator 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 oscillator 302 is mounted on the wiring board 360 so as to close the opening 361 by its lower surface. As a result, the second recess K2 is formed by the lower surface of the crystal oscillator 302 and the inner peripheral surface of the opening 361. From another point of view, an H-shaped package is realized by the package of the crystal oscillator 302 and the wiring board 360. The temperature sensitive element 130 is mounted on the lower surface of the crystal oscillator 302 exposed to the opening 361. As a result, the crystal oscillator 301 is a crystal oscillator with a temperature-sensitive component.

The insulating substrate 310 of the element mounting member 300 has a configuration in which the second frame portion 110c is removed from the insulating substrate 110 of the first embodiment. That is, the insulating substrate 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 board 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 substrate 310. The other two of the four mounting terminals 318 are electrically connected to a pair of connection pads 115 via wiring conductors (not shown) provided on the insulating substrate 310.

The wiring board 360 may have the same configuration as, for example, a rigid type printed wiring board. The wiring board 360 has an insulating substrate 362 and various conductors (for example, metal) provided on the insulating substrate 362. As for various conductors, for example, a plurality of (four in this embodiment) mounting pads 363 for mounting the crystal oscillator 302 on the wiring board 360, and the wiring board 360 (crystal oscillator 301) are mounted on the circuit board 180 (FIG. 2). (See) are a plurality of (four in this embodiment) external terminals 113 for mounting, and a wiring conductor (not shown) connecting the plurality of mounting pads 363 and the plurality of external terminals 113. Although not particularly shown, the wiring board 360 may have a solder resist that covers the insulating substrate 362 while exposing the external terminal 113 and the mounting pad 363.

The plurality of mounting terminals 318 of the crystal oscillator 302 and the plurality of mounting pads 363 of the wiring board 360 are arranged to face each other, and are joined by a joining material 365 interposed between them. As a result, two of the four external terminals 113 are electrically connected to the pair of electrode pads 111. Further, the other two of the four external terminals 113 are electrically connected to the pair of connection pads 115. The joining material 365 is made of solder or the like.

A gap having a total thickness of the mounting terminal 318, the joining material 365, and the mounting pad 363 is formed between the lower surface of the board portion 110a and the upper surface of the wiring board 360. In this gap, gas may be allowed to flow from the second recess K2 to the outside of the side surface of the crystal oscillator 301 or in the opposite direction, and such a gas may be filled with the resin 135. The flow of may be prohibited. The filling height of the resin 135 with respect to the second recess and / or the temperature sensing 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 substrate portion 110a (not shown). example). When the outer edge of the insulating substrate 362 is substantially the same as 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 substantially the same. 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 generally the same as described above. It may be equivalent, the external terminal 113 may have a larger area than the mounting pad 363 and the mounting terminal 318, and / or may be located outside, and the external terminal 113 and the mounting pad 363 may be located. The area may be larger than the mounting terminal 318 and / or may be located outside.

The bottom view of the crystal oscillator 301 is the same as that of FIG. 3 of the first embodiment. Therefore, FIG. 3 may be incorporated as a bottom view of the crystal oscillator 301 by substituting the reference numerals and the like of the second frame portion 110c with the reference numerals and the like of the wiring board 360. Further, 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 (board 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 are assumed to substantially coincide with each other. Therefore, for example, the relative position and size of the outer terminal 113 or the second recess K2 with respect to the outer edge of the substrate portion 110a or the region formed by the outer edge, and the outer terminal 113 with respect to the outer edge of the second frame portion 110c or the region formed by the outer edge. Alternatively, the description is made without distinguishing 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, for example, the external to the outer edge of the insulating substrate 362 of the wiring board 360 or the region 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 with reference to the outer edge of the insulating substrate 362.

In addition, the description of the relative position and size of the external terminal 113 or the second recess K2 in the first embodiment is based on 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 the region formed by the outer edge. It may be applied to a specific position and size. For example, the condition that the area ratio S2 / S1 is 0.75 or more and 0.91 or less is satisfied when the area of the rectangular region formed by the outer edge of the insulating substrate 362 is S1, and the rectangle formed by the outer edge of the substrate portion 310a is satisfied. It may also hold when the area of the region is S1.

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, as in the present embodiment, the conditions such as the distance s1 and the area ratio are set. It may be applied with reference to the outer edge of the second frame portion 110c. In addition, it may be applied to the substrate portion 110a.

The mounting terminal 318 of the crystal oscillator 302 may be in contact with or separated from the outer edge of the substrate portion 310a. In the case of being separated, the description of 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 the region formed by the outer edge in the first embodiment is described as the outer edge of the substrate portion 310a. Alternatively, it may or may not be used to explain 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, like the external terminal 113 shown in FIG. 3, the second recess K2 is formed from a rectangle having four sides parallel to the four sides of the board portion 310a. 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 separated from the outer edge of the insulating substrate 362 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 or the region formed by the outer edge in the first embodiment is provided by the outer edge of the insulating substrate 362 or the outer edge thereof. It may or may not be incorporated into the description of the relative position and size of the mounting pad 363 with respect to the region. The planar shape of the mounting pad 363 may be an appropriate shape, for example, from a rectangle having four sides parallel to the four sides of the insulating substrate 362, like the external terminal 113 shown in FIG. 3, the second recess K2. The shape may be such that a part of the side is removed.

As described above, in the present embodiment, the crystal oscillator 1 includes a substrate (board portion 310a), a frame body (insulation substrate 362 of the wiring board 360), an electrode pad 111, a connection pad 115, and a plurality of external terminals. It has 113, a piezoelectric element (crystal 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 pair of short side regions of the substrate portion 310a on the lower surface of the substrate portion 310a, and the pair of portions of the insulating substrate 362 includes a pair of portions (short side portions). A recess (second recess K2) is formed between them. 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 in 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 airtightly seals the crystal element 120. The ratio S2 / S1 of the area S1 of the rectangular region formed by the outer edge of the lower surface of the wiring board 360 to the area S2 of the smallest rectangular region R1 including all the external terminals 113 is 0.75 or more and 0.91 or less.

Therefore, the same effect as that of the first embodiment is obtained. Specifically, for example, since the area S2 is smaller than the area S1, the force applied to the insulating substrate 362 from the circuit board 180 via the plurality of external terminals 113 tends to cause the insulating substrate 362 to warp. It becomes difficult to act as bending stress. As a result, the bending stress transmitted from the wiring board 360 to the substrate portion 310a via the joining material 365 that joins the wiring board 360 and the substrate portion 310a is reduced. As a result, the bending stress transmitted from the substrate portion 310a to the crystal element 120 via the conductive adhesive 150 is also reduced. As a result, the change (increase) in the hysteresis characteristic caused by mounting on the circuit board 180 is reduced, and eventually the hysteresis characteristic itself is also reduced.

Further, in the present embodiment, the crystal oscillator 301 has a mounting terminal 318 located on the lower surface of the substrate portion 310a, a mounting pad 363 located on the upper surface of the insulating substrate 362 of the wiring board 360, and a mounting terminal 318. Further has a conductive bonding material 365 for bonding the mounting pad 363 and 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 aligned with 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 cushioning material for relieving stress. Although it depends on the dimensions of the crystal oscillator 302, the wiring board 360, the circuit board 180, the coefficient of thermal expansion, and the like, the bending stress generated in the substrate portion 310a is reduced as compared with the first embodiment depending on the mode of stress distribution.

[Example]
Crystal oscillators according to Examples having different dimensions were prepared and their characteristics were measured. As a result, it was confirmed that the hysteresis characteristic can be reduced by reducing the area ratio S2 / S1. Specifically, it is as follows.

The configuration of the crystal oscillator according to the embodiment is that of the first embodiment. That is, the frame body is composed of the second frame portion 110c formed integrally with the substrate portion 110a. Further, the longitudinal direction of the second recess K2 and the temperature sensing element 130 is the lateral direction of the element mounting member 100.

The main design conditions of the crystal unit according to the embodiment are as follows.
Crystal piece 121: AT cut Thickness of crystal piece 121: 43 μm
Length of the long side of the substrate portion 110a: 1.6 mm
Length of the short side of the substrate portion 110a: 1.2 mm
Thickness of substrate 110a: 120 μm
Thickness of the second frame portion 110c: 230 μm
Material of insulating substrate 110: Alumina ceramics Area ratio S2 / S1: In the range of 0.729 or more and 1.000 or less, 11 types were set by changing by 0.02 to 0.03.

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

In this figure, the horizontal axis indicates the temperature T (° C.). The vertical axis on the left 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 oscillator by the design frequency F. It shows dF / F. The line Ln1 shows an example of the correspondence between the temperature T and the frequency difference dF / F when the temperature rises. The line Ln2 shows an example of the correspondence between the temperature T and the frequency difference dF / F when the temperature drops.

As can be seen from this figure, the actual frequency changes due to temperature changes. The crystal oscillator is configured, for example, so that the frequency difference dF / F approaches 0 at a predetermined reference temperature T0. The reference temperature T0 is set, for example, within a range of so-called normal temperature (for example, 5 ° C. or higher and 35 ° C. or lower). The lines Ln1 and Ln2 can be approximated by a cubic function, respectively. The temperature compensation circuit described above has coefficients and constants of an equation for specifying the correspondence 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 detected temperature of the temperature sensing element 130.

As can be understood from the comparison of the lines Ln1 and Ln2, the correspondence between the temperature T and the frequency difference dF / F is different between the time when the temperature rises and the time 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 the frequency difference ΔF / F. In FIG. 8, the vertical axis on the right side indicates 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 line Ln1 and the line Ln2 measure the frequency of the oscillation signal while, for example, raising the temperature from the lower limit side to the upper limit side of the illustrated range or lowering the temperature from the upper limit side to the lower limit side of the illustrated range. Obtained by that. However, the crystal unit actually used is exposed to more complicated temperature changes (temperature history). Therefore, the temperature compensation amount is not specified separately for the temperature rise and the temperature drop based on the lines Ln1 and Ln2, respectively, and the temperature compensation amount for the same temperature is the temperature rise and temperature drop. It is the same as time. Therefore, if the frequency difference ΔF / F is reduced, for example, the accuracy of temperature compensation is improved.

FIG. 9 is a diagram showing the hysteresis characteristics of the crystal oscillator in a state of being mounted on the circuit board 180. In these figures, the horizontal axis represents the temperature T (° C.). The vertical axis shows the normalized frequency difference ΔF / F (ppb: parts per billion) described with reference to FIG. The plurality of lines in the figure show the correspondence between the temperature T and the frequency difference ΔF / F in a plurality of examples in which the area ratios S2 / S1 are different from each other. On the right side of the page, the correspondence between the line type and the area ratio S2 / S1 is shown. Although not particularly shown, the ΔF / F of the crystal oscillator before being mounted on the circuit board 180 is generally within the range of 0 ± 50 (ppb).

The area ratio S2 / S1 = 1 indicates the characteristics of the crystal unit according to the comparative example. Then, by making the area ratio S2 / S1 smaller than 1, the frequency difference ΔF / F becomes smaller. In particular, when the area ratio S2 / S1 is 0.91 or less (rounded to the first decimal place), a significant difference from the comparative example is observed over the entire temperature range (-30 ° C to 90 ° C) shown in the figure. Be done. Further, as the area ratio S2 / S1 becomes smaller, the frequency difference ΔF / F becomes smaller and approaches 0. Therefore, in the range shown in the figure, it can be seen that the smaller the product ratio S2 / S1, the better, only from the viewpoint of reducing the frequency difference ΔF / F.

In the above embodiment, the crystal oscillators 1, 1-1, 201 and 301 are examples of piezoelectric devices, respectively. The substrate portions 110a and 310a are examples of substrates, respectively. The second recess K2 is an example of the recess. The second frame portion 110c and the wiring board 360 are examples of the frame body, respectively. 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 technique according to the present disclosure is not limited to the above embodiments and modifications, and may be implemented in various embodiments.

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

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

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

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. Processing includes, for example, amplification, modulation, filtering and computation based on the detection temperature. In other words, the temperature sensitive component may be an integrated circuit element (IC) including a temperature sensitive element.

The IC as a temperature-sensitive component is an oscillation circuit that generates an oscillation signal by applying a voltage to the vibration element when the piezoelectric element is a vibration element used for the vibrator, and the temperature detected by the temperature-sensing element. It may include a compensation circuit that compensates for the temperature of the frequency characteristic of the vibrating element based on the above. That is, the piezoelectric device may be a temperature-compensated 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 vibrating element and the external terminal are not directly connected. Further, the electric signal output from the terminal of the IC (terminal of the temperature sensitive component) to the external terminal is, for example, an oscillation signal, not a signal including temperature information. As can be understood from this example, the temperature sensitive component may be used inside the temperature sensitive component without outputting the electric signal generated according to the temperature to the connection pad.

In the embodiment, the first frame portion 110b is provided on the substrate (board portion 110a), and a flat plate-shaped lid is placed on the first frame portion 110b. However, the first frame portion 110b may not be provided, and a box-shaped lid with an open lower portion may be joined to the upper surface of the substrate to seal the piezoelectric element.

In the embodiment, the frame body (second frame portion 110c and wiring board 360) is an annular shape extending along the entire circumference of the board. However, the frame does not have to be annular. For example, the frame may be configured to have a pair of portions extending along a pair of short sides of the substrate and no portions extending along a pair of long sides of the substrate.

The number of external terminals may be larger than four. For example, five or more external terminals may be arranged along the outer edge of the underside of the package. Similarly, other terminals or pads such as an external pad and a connection pad may be provided in a number other than those shown in the figure.

All of the plurality of external terminals need not be separated from the outer edge of the lower surface of the frame. Further, the entire external terminal does not have to 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 the self, or may be separated only from the short side adjacent to the self.

1 ... Crystal oscillator (piezoelectric device), 110a ... Substrate (board), 110c ... Second frame (frame), 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 (concave).

Claims (8)

With a rectangular board,
A frame body including a pair of portions of the lower surface of the substrate located in a region on the short side side of the substrate, and forming a recess between the pair of portions.
The electrode pads located on the upper surface of the substrate and
A connection pad located on the lower surface of the substrate in the frame and
A plurality of external terminals located on the lower surface of the frame,
The piezoelectric element mounted on the electrode pad and
The temperature-sensitive components mounted on the connection pad and
A lid that airtightly seals the piezoelectric element and
Have and
A piezoelectric device having a ratio S2 / S1 of 0.75 or more and 0.91 or less between the area S1 of the rectangular area formed by the outer edge of the lower surface of the frame and the area S2 of the smallest rectangular area including all the external terminals. .. The piezoelectric device according to claim 1, wherein the substrate and the frame are directly bonded to each other. The mounting terminals located on the lower surface of the board and
The mounting pad located on the upper surface of the frame and
A conductive joining material that joins the mounting terminal and the mounting pad,
The piezoelectric device according to claim 1, further comprising. The piezoelectric device according to any one of claims 1 to 3, wherein the electrode pad is entirely located outside the recess in plan perspective. The piezoelectric device according to any one of claims 1 to 4, wherein the recess and the temperature-sensitive component have a shape in which the opposite direction of a pair of long sides of the substrate is the longitudinal direction. The piezoelectric device according to any one of claims 1 to 5, wherein the center of the recess is located on the side opposite to the center of the substrate with respect to the center of the electrode pad in planar fluoroscopy. The piezoelectric device according to any one of claims 1 to 6, further comprising an insulating resin that is in close contact with the temperature-sensitive component and the lower surface of the substrate. The piezoelectric device according to any one of claims 1 to 7.
With the substrate
A plurality of external pads located on the surface of the substrate and joined to the plurality of external terminals.
Have an electronic device.

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