JP2019068287A - Piezoelectric vibrator - Google Patents

Abstract

To provide a piezoelectric vibrator that can suitably detect temperature.SOLUTION: A crystal oscillator 1 has a package 110, a lid body 140, a crystal element 120, and a temperature sensor 130. The package 110 has a concave part K1. The lid body 140 closes an opening of the concave part K1 to hermetically seal the inside of the concave part K1. The crystal element 120 is accommodated in the concave part K1 and mounted in a first area R1 facing the lid body side of inner surfaces of the concave part K1. The temperature sensor 130 is accommodated in the concave part K1 and mounted in a second area R2 facing the lid body side of the inner surfaces of the concave part K1, and detects temperature on a principal surface 132a on the second area R2 side.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a piezoelectric vibrator such as a quartz vibrator.

  A quartz oscillator having a temperature sensor is known (for example, Patent Document 1). Patent Document 1 proposes using a diode (semiconductor diode, hereinafter the same) as a temperature sensor. The detected value of the temperature sensor is used, for example, in a temperature compensation circuit that compensates for the characteristic change of the crystal element due to the temperature change.

JP, 2014-86937, A

  It is desirable to provide a piezoelectric vibrator capable of suitably detecting the temperature.

  A piezoelectric vibrator according to an aspect of the present disclosure includes a package having a recess, a lid closing the opening of the recess to hermetically seal the inside of the recess, and the lid accommodated in the recess. The piezoelectric element mounted in a first region of the inner surface of the recess facing the lid, and the second region of the inner surface of the recess that faces the lid And a temperature sensor for detecting a temperature on the surface on the second area side.

  In one example, the temperature sensor has a sensor substrate surface-mounted to face the second region, and an electric characteristic located on the second region side of the sensor substrate changes in accordance with a temperature And a temperature measuring unit.

  In one example, the temperature sensor has a semiconductor substrate surface-mounted to face the second region, and the main surface of the semiconductor substrate on the second region side constitutes a diode p. It contains a type area and an n-type area.

  In one example, the piezoelectric element is supported only at one end side in a first direction parallel to the bottom surface of the recess, and the semiconductor substrate has a partial region of one of the p-type region and the n-type region. And a second layer constituting the other of the p-type region and the n-type region by being located on the first layer in a region different from the partial region. At least a part of the second layer is located on one side or the other side of the first direction with respect to the support position of the piezoelectric element.

  In one example, the piezoelectric element is supported only at one end side in a first direction parallel to the bottom surface of the recess, and in plan view of the semiconductor substrate, at least at a boundary portion between the p-type region and the n-type region. A portion is located on one side or the other side of the first direction with respect to the support position of the piezoelectric element and extends along the first direction.

  In one example, in a plan view of the semiconductor substrate, 80% or more of the p-type region is one side in a direction orthogonal to the first direction with respect to the portion extending along the first direction of the boundary portion. And 80% or more of the n-type region is located on the other side of the direction orthogonal to the first direction.

  In one example, in a plan view of the recess, the piezoelectric element is supported only at one end side in the first direction, and the support position is located at the one end side in the first direction with respect to the center of the package. The center of the temperature sensor is located closer to the one end in the first direction than the center of the package in a plan view of the recess.

  In one example, the first region is a top surface of a pedestal located on the bottom surface of the recess, the second region is a bottom surface of the recess, and a height of the pedestal from the bottom surface of the recess is And a height lower than the height from the pedestal to the lid.

  In one example, the first region and the second region are flush.

  A piezoelectric vibrator according to an aspect of the present disclosure includes a package having a recess, a lid closing the opening of the recess to hermetically seal the inside of the recess, and the lid accommodated in the recess. The piezoelectric element mounted in a first region of the inner surface of the recess facing the lid, and the second region of the inner surface of the recess that faces the lid A temperature sensor, and the temperature sensor has a semiconductor substrate surface-mounted to face the second region, and the main surface of the semiconductor substrate on the second region side Includes a p-type region and an n-type region constituting a diode.

  According to the above configuration, the temperature can be suitably detected.

It is an exploded perspective view showing the composition of the crystal oscillator concerning a first embodiment. Fig.2 (a) is a top view which shows a part of crystal oscillator of FIG. 1, FIG.2 (b) is sectional drawing in the IIb-IIb line of Fig.2 (a). It is a top view which shows the example of wiring in the crystal oscillator of FIG. 4 (a) is a plan view showing the appearance of the temperature sensor, FIG. 4 (b) is a plan view showing the configuration of the semiconductor substrate of the temperature sensor of FIG. 4 (a), and FIG. It is sectional drawing in the IVc-IVc line | wire of 4 (a). Fig.5 (a) is a top view which shows the principal part structure of the crystal oscillator which concerns on 2nd embodiment, FIG.5 (b) is sectional drawing in the Vb-Vb line of FIG. 5 (a). 6 (a), 6 (b) and 6 (c) are schematic diagrams for explaining various modified examples. FIG. 7A is a cross-sectional view of a temperature sensor according to a modification, and FIG. 7B is a plan view showing a configuration of a semiconductor substrate of the temperature sensor of FIG. 7A.

  Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. In the drawings, for convenience, an orthogonal coordinate system consisting of D1 axis, D2 axis and D3 axis may be added. The crystal unit according to the embodiment may be used with either direction upward or downward. However, in the following, for convenience, terms such as the upper surface or the lower surface may be used with the positive side of the D3 axis as the upper side or the upper side of the sheet of the drawing currently described.

  In the description of the second embodiment and the subsequent embodiments, the same reference numerals as those of the above-described embodiment are used for the same or similar components as the above-described embodiment, and the illustration and description thereof will be omitted. Sometimes. In addition, about the structure which respond | corresponds (similar) to the structure of embodiment described previously, even when the code | symbol different from the structure of embodiment described previously is attached, the point which is not particularly described is demonstrated previously. The configuration of the embodiment may be the same.

First Embodiment
FIG. 1 is an exploded perspective view showing a schematic configuration of a crystal unit 1 according to the first embodiment. FIG. 2A is a plan view showing the inside of the crystal unit 1. FIG.2 (b) is sectional drawing in the IIb-IIb line | wire of FIG. 2 (a).

  The quartz crystal vibrator 1 is, for example, an electronic component which is generally in the form of a thin rectangular solid as a whole, and the dimensions thereof may be appropriately set. For example, if the length is relatively small, the length of the long side (D1 axis direction) is 1.5 mm or more and 3.0 mm or less, and the length of the short side (D2 axis direction) is 1.0 mm or more and 2.5 mm or less (but the length And the thickness (in the direction of the D3 axis) is 0.4 mm or more and 1.5 mm or less (but shorter than the short side).

  The crystal unit 1 has a package 110 having a recess K1, a crystal element 120 and a temperature sensor 130 accommodated in the recess K1, and a lid 140 for closing the recess K1. In addition, while FIG. 2 (a) abbreviate | omits the cover body 140, the crystal element 120 is shown by the imaginary line (two-dot chain line).

(package)
The outer shape of the package 110 is, for example, a substantially rectangular parallelepiped shape. The recess K1 of the package 110 has, for example, an element recess K2 in which the quartz crystal element 120 is accommodated, and a sensor recess K3 which is opened in the bottom of the element recess K2 and in which the temperature sensor 130 is accommodated. There is. In another aspect, the package 110 has a pedestal 118 located on the bottom of the recess K1. The upper surface of the pedestal portion 118 is a first region R1 for mounting the crystal element 120. The bottom surface of the recess K1 (the non-arrangement region of the pedestal portion 118) is a second region R2 for mounting the temperature sensor 130. The first region R1 and the second region R2 are regions of the inner surface of the recess K1 facing the lid 140 side.

  As shown in FIG. 2B, the package 110 is configured of, for example, a plurality of (three in the present embodiment) first to third insulating layers 110a to 110c. Specifically, for example, the package 110 has a first insulating layer 110a, a second insulating layer 110b having an opening forming the sensor recess K3, and an opening forming the element recess K2 in this order from the lower surface side. And a third insulating layer 110c. The bottom surface (second region R2) of the recess K1 is configured by the upper surface of the first insulating layer 110a. The first region R1 is constituted by the upper surface of the second insulating layer 110b.

  The shapes of the outer edges of the first insulating layer 110a to the third insulating layer 110c are, for example, rectangular corresponding to the external shape of the package 110 being rectangular. The planar shape of the sensor recess K3 and the element recess K2 is, for example, a rectangle located at the center of the insulating layer and having four sides parallel to the rectangle of the outer edge of the insulating layer. Although not particularly illustrated, in the second insulating layer 110b, the shape on the positive side in the D1-axis direction may be similar to that of the third insulating layer 110c. That is, the portion on the D1 axial direction positive side having the same shape as the pedestal portion 118 may not be provided. Further, the pedestal portion 118 may be divided in the D2 axis direction corresponding to two electrode pads 111 described later.

  The thicknesses of the respective insulating layers (110a to 110c) may be identical to one another or may be different from one another. In the illustrated example, the thickness of the second insulating layer 110 b is larger than the thickness of the third insulating layer 110 c. That is, the height from the bottom surface (second region R2) of the recess K1 to the first region R1 is lower than the height from the first region R1 to the upper surface of the package 110 (or the lower surface of the lid 140).

  Each insulating layer (110a to 110c) is made of, for example, a ceramic material such as alumina ceramic or glass-ceramic. Each of the first insulating layer 110a to the third insulating layer 110c may be a single insulating layer or a plurality of insulating layers stacked.

  In the package 110 configured as described above, for example, a conductor made of metal or the like is disposed as described below.

  The first external connection electrode terminals G1 (G1a, G1b) and the second external connection electrode terminals G2 (G2a, G2b) are provided on the lower surface of the first insulating layer 110a. These terminals are used to input or output signals to the crystal unit 1. That is, when the crystal unit 1 is mounted on a circuit board (not shown) or the like, the pads of the circuit board and these terminals are joined by solder or the like. The first external connection electrode terminal G1 is a terminal electrically connected to the crystal element 120. The second external connection electrode terminal G2 is a terminal electrically connected to the temperature sensor 130.

  The external connection electrode terminals (G1 and G2) are, for example, conductor layers having an appropriate planar shape (for example, a rectangular shape), and provided at four corners of the lower surface of the first insulating layer 110a. The positional relationship between these four terminals and the four corners may be set appropriately. For example, the pair of first external connection electrode terminals G1 is provided to be located diagonally on the lower surface of the first insulating layer 110a. Further, the second external connection electrode terminal G2 is provided so as to be located at a diagonal different from that at which the first external connection electrode terminal G1 is provided.

  A pair of electrode pads 111 for mounting the crystal element 120 is provided in the first region R1. The pair of electrode pads 111 is a conductor layer having an appropriate planar shape (for example, a rectangle), and is provided adjacent to one another along one side of the recess K1, for example. The pair of electrode pads 111 is electrically connected to the pair of first external connection electrode terminals G1 via a conductor (described later) provided in the package 110.

  The second region R2 is provided with a pair of bonding pads 115 (115a, 115b) for mounting the temperature sensor 130. The pair of bonding pads 115 is a conductor layer having an appropriate planar shape (for example, a rectangular shape), and is provided, for example, to align in a direction intersecting (for example, orthogonal to) the arranging direction of the pair of electrode pads 111. The pair of bonding pads 115 is electrically connected to the pair of second external connection electrode terminals G2 through a conductor (described later) provided in the package 110.

  FIG. 3 is a plan view showing an example of a conductor connecting the electrode pad 111 and the first external connection electrode terminal G1, and a conductor connecting the bonding pad 115 and the second external connection electrode terminal G2. This figure shows the top surface of the first insulating layer 110a. Further, the electrode pad 111, the first external connection electrode terminal G1, and the second external connection electrode terminal G2 are also shown by dotted lines.

  In the example of this figure, the electrode pad 111 on the positive side of the D2 axis is provided on the upper surface of the first insulating layer 110a and a via conductor (not shown) which passes through the second insulating layer 110b directly below the electrode pad 111. The first external connection electrode terminal G1a is connected to the first external connection electrode terminal G1a via the crystal element wiring pattern 113 and the first via conductor 114 penetrating the first insulating layer 110a immediately above the first external connection electrode terminal G1a. Further, the electrode pad 111 on the negative side of the D2 axis has a via conductor (not shown) directly below the electrode pad 111 and penetrating the second insulating layer 110b, and the first insulating layer 110a directly on the first external connection electrode terminal G1b. Are connected to the first external connection electrode terminal G1b via the first via conductor 114 passing through. A crystal element wiring pattern 113 may be interposed between the D 2 -axis negative electrode pad 111 and the first external connection electrode terminal G 1 b as necessary. Although not particularly illustrated, the conductor connecting the electrode pad 111 and the first external connection electrode terminal G1 may include a wiring pattern provided on the upper surface of the second insulating layer 110b.

  In addition, the bonding pad 115a includes the sensor wiring pattern 116a provided on the upper surface of the first insulating layer 110a, and the second via conductor 117a penetrating the first insulating layer 110a immediately above the second external connection electrode terminal G2b. And the second external connection electrode terminal G2a. The bonding pad 115b includes the sensor wiring pattern 116b provided on the upper surface of the first insulating layer 110a, and the second via conductor 117b penetrating the first insulating layer 110a immediately above the second external connection electrode terminal G2b. The second external connection electrode terminal G2b is connected via the second external connection electrode terminal G2b.

  In the illustrated example, the second via conductor 117b is positioned closer to the bonding pad 115b than the electrode pad 111, and the sensor wiring pattern 116a is positioned closer to the bonding pad 115b than the electrode pad 111. . However, the second via conductor 117 b may be located on the opposite side to the bonding pad 115 b than the electrode pad 111, and the sensor wiring pattern 116 a may extend between the pair of electrode pads 111.

  Referring back to FIGS. 1 to 3, the sealing conductor pattern 112 serves to improve the wettability of the sealing member 141 when the top surface of the package 110 and the lid 140 are joined via the sealing member 141. Plays. The sealing conductor pattern 112 is formed to a thickness of, for example, 10 to 25 μm by sequentially applying nickel plating and gold plating to the surface of the conductor pattern made of, for example, tungsten or molybdenum.

  Although not particularly illustrated, a conductor may be provided to electrically connect the second external connection electrode terminal G2a (or G2b) and the sealing conductor pattern 112. The said conductor contains the via conductor which penetrates the 1st insulating layer 110a-the 3rd insulating layer 110c, for example. The via conductor 117 connecting the bonding pad 115a and the second external connection electrode terminal G2a may be used as the via conductor penetrating the first insulating layer 110a. For example, a reference potential is applied to the second external connection electrode terminal G2a. Thereby, the shielding property of the lid 140 joined to the sealing conductor pattern 112 is improved.

(Lid)
The lid 140 is made of, for example, an alloy containing at least one of iron, nickel or cobalt. Such a lid 140 is for airtightly sealing the recess K1 in a vacuum state or the recess K1 filled with nitrogen gas or the like. Specifically, the lid 140 is placed on the third insulating layer 110 c of the package 110 in a predetermined atmosphere, and the sealing conductor pattern 112 of the third insulating layer 110 c and the sealing member 141 of the lid 140 Is welded to the third insulating layer 110c by applying a predetermined current to perform seam welding.

  The sealing member 141 is provided at a position of the lid 140 opposite to the sealing conductor pattern 112 provided on the top surface of the package 110. The sealing member 141 is provided by, for example, silver solder or gold-tin. In the case of silver wax, the thickness is 10 to 20 μm. For example, the component ratio of silver of 72 to 85% and copper of 15 to 28% is used. In the case of gold-tin, its thickness is 10 to 40 μm. For example, a component ratio of 78 to 82% of gold and 18 to 22% of tin is used.

(Crystal element)
The quartz crystal element 120 is bonded onto the electrode pad 111 via the conductive adhesive 150, as shown in FIG. 2 (b). The quartz crystal element 120 plays a role of oscillating a reference signal of an electronic device or the like by the stable mechanical vibration and the piezoelectric effect.

  The quartz crystal element 120 has a structure in which the excitation electrode 122, the connection electrode 123, and the lead-out electrode 124 are attached to the upper surface and the lower surface of the quartz crystal substrate 121, respectively. The excitation electrode 122 is formed by depositing and forming a metal on each of the upper surface and the lower surface of the quartz crystal substrate 121 in a predetermined pattern. The extraction electrode 124 is extended from the excitation electrode 122 toward the short side of the quartz substrate 121. The connection electrode 123 is connected to the lead-out electrode 124 and is provided in a shape along the long side or the short side of the quartz substrate 121.

  In this embodiment, one end of the quartz crystal element 120 connected to the electrode pad 111 is a fixed end connected to the inner surface (first region R1) of the package 110, and the other end is spaced apart from the inner surface of the package 110. The quartz crystal element 120 is fixed on the first region R1 with a piece holding structure as an end.

  The outer peripheral edge on the fixed end side of the quartz crystal base plate 121 is parallel to one side of the package 110 in plan view, and is provided to approach the inner peripheral surface of the recess K1. By doing this, the mounting position of the quartz crystal element 120 can be visually made easier to understand, so that the productivity of the quartz oscillator can be improved.

  Here, the operation of the crystal element 120 will be described. In the quartz crystal element 120, when an alternating voltage from the outside is applied to the quartz crystal base plate 121 from the connection electrode 123 through the extraction electrode 124 and the excitation electrode 122, the quartz crystal base plate 121 is excited in a predetermined vibration mode and frequency. Is supposed to wake up.

  Here, a method for manufacturing the crystal element 120 will be described. First, in the crystal element 120, the artificial crystal is cut at a predetermined cut angle to obtain the crystal base plate 121. Next, bevel processing is performed to reduce the thickness of the outer periphery of the quartz crystal substrate 121 so that the central portion of the quartz crystal substrate 121 is thicker than the outer periphery of the quartz crystal substrate 121. Then, a metal film is attached to both main surfaces of the quartz crystal substrate 121 by photolithography, vapor deposition or sputtering to form the excitation electrode 122, the connection electrode 123, and the lead-out electrode. Thus, the quartz crystal element 120 is manufactured. In addition, a main surface means the widest surface (namely, surface and back) of a plate-shaped member. The same applies below.

  A method of bonding the crystal element 120 to the first region R1 will be described. First, the conductive adhesive 150 is applied onto the electrode pad 111 by, for example, a dispenser. The quartz crystal element 120 is carried on the conductive adhesive 150 and placed on the conductive adhesive 150. The conductive adhesive 150 is cured and shrunk by heat curing. The quartz crystal element 120 is bonded to the pair of electrode pads 111.

  The conductive adhesive 150 contains a conductive powder as a conductive filler in a binder such as silicone resin, and as the conductive powder, aluminum, molybdenum, tungsten, platinum, palladium, silver, titanium, Those containing either nickel or iron or combinations thereof are used. Moreover, as a binder, a silicone resin, an epoxy resin, a polyimide resin, or bis maleimide resin is used, for example.

(Temperature sensor)
The temperature sensor 130 includes a diode and has an anode terminal 131 b and a cathode terminal 131 a. The temperature sensor 130 has forward characteristics in which current flows from the anode terminal 131b to the cathode terminal 131a but hardly flows current from the cathode terminal 131a to the anode terminal 131b. The forward characteristics of the temperature sensor 130 largely change with temperature. Specifically, the forward voltage when a constant current is supplied to the temperature sensor 130 changes linearly (linearly) with respect to the temperature change. Temperature information can be obtained by measuring this voltage. The temperature information is used, for example, by a main IC (Integrated Circuit) such as an electronic device (not shown) to compensate for the characteristic change of the crystal oscillator due to the temperature change.

  The temperature sensor 130 is mounted on the bonding pad 115 provided in the second region R2 of the package 110 via a conductive bonding material such as solder. The cathode terminal 131a of the temperature sensor 130 is connected to one of the bonding pads 115a, and the anode terminal 131b is connected to the other bonding pad 115b. Therefore, the cathode terminal 131a of the temperature sensor 130 is connected to one of the second external connection electrode terminals G2a to which the reference potential is applied. In another point of view, the voltage according to the temperature of the temperature sensor 130 is output to the outside of the quartz oscillator through the other second external connection electrode terminal G2b.

  In addition, since a current of 1 to 200 μA flows through the temperature sensor 130, a sufficient current can be secured even when the circuit disposed on the motherboard of the electronic device has a high impedance. As a result, it is possible to reduce the superposition of noise caused by the small current value in the temperature sensor 130. In addition, since the amount of current flowing rapidly does not increase unless the forward voltage of the temperature sensor 130 is exceeded, the amount of heat generation of the temperature sensor 130 can be reduced, and reading with the actual temperature of the crystal element 120 By reducing the error, high-precision correction is possible. Therefore, the crystal unit can improve the accuracy of the temperature compensation regarding the oscillation frequency of the crystal element 120.

  The temperature sensor 130 is disposed at a position overlapping with the crystal element 120 in plan view. For example, the temperature sensor 130 is disposed in an area consisting of the long side 1.0 to 1.6 mm and the short side 0.8 to 1.2 mm of the quartz crystal substrate 121. In plan view, the center of the temperature sensor 130 (graphic centroid) substantially coincides with, for example, the center of the package 110 (graphic centroid) and / or the center of the crystal element 120 (graphic centroid).

  The temperature sensor 130 is located in the plane of the excitation electrode 122 provided on the quartz crystal element 120 in plan view. Therefore, the temperature sensor 130 can be protected from noise from other semiconductor components such as a power amplifier constituting the electronic device or electronic components by the shielding effect of the metal film of the excitation electrode 122. Thus, the temperature sensor 130 can output the voltage accurately.

  A method of bonding the temperature sensor 130 to the package 110 will be described. First, the conductive bonding material is applied onto the bonding pad 115 by, for example, a dispenser. The temperature sensor 130 is transported onto the conductive bonding material and placed on the conductive bonding material. The conductive bonding material is melt-bonded by heating. The temperature sensor 130 is bonded to the pair of bonding pads 115. The conductive bonding material may be applied to the cathode terminal 131 a and the anode terminal 131 b instead of the bonding pad 115.

  The conductive bonding material is made of, for example, silver paste or lead-free solder. In addition, the conductive bonding material contains an added solvent for adjusting the viscosity to be easy to apply. The component ratio of lead-free solder is 95 to 97.5% of tin, 2 to 4% of silver, and 0.5 to 1.0% of copper.

(Specific configuration of temperature sensor)
FIG. 4A is a plan view showing the appearance of the temperature sensor 130. FIG. FIG. 4B is a plan view showing the configuration of the semiconductor substrate 132 of the temperature sensor 130. FIG.4 (c) is sectional drawing in the IVc-IVc line of FIG. 4 (a). However, for the sake of convenience, the cross section of the semiconductor substrate 132 is not hatched.

  The temperature sensor 130 is configured by providing a cathode terminal 131 a and an anode terminal 131 b on the main surface 132 a of the semiconductor substrate 132. That is, the temperature sensor 130 is a bare chip and does not have a package surrounding the semiconductor substrate 132.

  The semiconductor substrate 132 has, for example, a substantially constant thickness over the entire surface. The planar shape of the semiconductor substrate 132 may be set as appropriate, but is, for example, roughly rectangular (rectangular in the illustrated example). The cathode terminal 131a and the anode terminal 131b are arranged to be separated from each other in a direction (D1 axis direction) in which two sides (short sides in the illustrated example) of the rectangles face each other.

  The semiconductor substrate 132 has, in the main surface 132a, a p-type region 132p made of a p-type semiconductor and an n-type region 132n made of an n-type semiconductor. More specifically, the semiconductor substrate 132 is an n-type layer 133n made of an n-type semiconductor, and a p-type semiconductor made of a p-type semiconductor located on the n-type layer 133n in a partial region of the n-type layer 133n. And a layer 133p. A p-type region 132p is formed by the p-type layer 133p, and an n-type region 132n is formed by the non-arrangement region of the p-type layer 133p in the n-type layer 133n.

  The thicknesses of the n-type layer 133 n and the p-type layer 133 p may be set as appropriate. In the illustrated example, the thickness of the n-type layer 133 n in the n-type region 132 n is the thickness of the semiconductor substrate 132. The thickness of the p-type layer 133 p is, for example, half or less of the thickness of the semiconductor substrate 132.

  The p-type layer 133p and the n-type layer 133n are in contact with each other to constitute a pn junction. An anode terminal 131b is provided on the p-type region 132p, and a cathode terminal 131a is provided on the n-type region 131n. Thus, the diode 134 is formed on the semiconductor substrate 132. As understood from the above description, the diode 134 has a so-called planar structure.

  The manufacturing method of such a diode 134 may be similar to various known manufacturing methods except for specific conditions such as dimensions. For example, first, an n-type semiconductor wafer in which a plurality of semiconductor substrates 132 are taken is prepared. The n-type semiconductor wafer is, for example, a silicon (Si) wafer containing phosphorus (P) or antimony (Sb) or the like as an impurity. Next, an impurity such as boron (B) is implanted into a region to be the p-type region 132p through a mask. Next, the anode terminal 131b and the cathode terminal 131a are formed by an appropriate thin film formation method. Thereafter, the semiconductor wafer is diced into pieces.

  When a forward voltage is applied to the anode terminal 131b and the cathode terminal 131a in the diode 134 configured as described above, the anode terminal 131b and the cathode terminal 131a are located on the main surface 132a, as indicated by the arrow y1. Thus, the current tends to flow near the major surface 132a. In another aspect, the current tends to flow beyond the boundary 132 b (pn junction surface) of the p-type region 132 p and the n-type region 132 n in plan view.

  Since the p-type layer 133p is located on the n-type layer 133n, as shown by the arrow y2, even through the interface 133b (pn junction surface) between the lower surface of the p-type layer 133p and the n-type layer 133n. Current can flow. However, as the boundary surface 133b is separated from the main surface 132a, the current path from the anode terminal 131b to the cathode terminal 131a via the boundary surface 133b becomes longer. As a result, the resistance of the path increases and the current is less likely to flow.

  Therefore, in the diode 134, among the temperatures of various portions in the semiconductor substrate 132, the temperature at the main surface 132a has a large influence on the forward characteristics of the diode 134. Depending on the depth of the position of the boundary surface 133b, the relative proportion of the boundary portion 132b and the boundary surface 133b on the forward characteristics changes, but the temperature itself on the major surface 132a has a large influence on the forward characteristics. There is no change.

  Even if the p-type layer 133p has a thickness equal to that of the semiconductor substrate 132, the lower surface of the semiconductor substrate 132 is similar to the above because the anode terminal 131b and the cathode terminal 131a are located on the main surface 132a. Since the current flowing to the side (the positive side of the D3 axis) becomes smaller, there is no change in the tendency that the temperature at the main surface 132a has a large influence on the forward characteristics.

  Therefore, the diode 134 is provided with the anode terminal 131b provided on the p-type region 131p constituting the main surface 132a and the cathode terminal 131a provided on the n-type region 131n constituting the main surface 132a. It can be said that the main surface 132a) is configured to detect the temperature (detect the temperature of the main surface 132a).

  As the p-type layer 133p is thinner, the temperatures of the boundary portion 132b and the boundary surface 133b become closer to the temperature of the main surface 132a, so the temperature of the main surface 132a can be detected with high accuracy. For example, the thickness of the p-type layer 133p may be 1⁄2 or less or 1⁄5 or less of the thickness of the semiconductor substrate 132.

  The p-type layer 133p is formed only on a part of the semiconductor substrate 132 on the main surface 132a side, and the anode terminal 131b and the cathode terminal 131a are located on the main surface 132a. The diode 134 may be considered to be configured in part of the main surface 132a. Also from this viewpoint, the temperature sensor 130 may be a sensor that detects the temperature on the surface (main surface 132a).

  In the illustrated example, the aspect in which a part of the n-type semiconductor wafer is a p-type semiconductor is taken as an example, but a part of a p-type semiconductor wafer may be an n-type semiconductor. That is, in the diode 134, the n-type layer may be located on the p-type layer in a partial region of the p-type layer, whereby the p-type region 132p and the n-type region 132n may be formed in the main surface 132a. .

  As described above, the piezoelectric vibrator (quartz crystal vibrator 1) according to this embodiment includes the package 110, the lid 140, the piezoelectric element (quartz element 120), and the temperature sensor 130. The package 110 has a recess K1. The lid 140 closes the opening of the recess K1 to hermetically seal the inside of the recess K1. The quartz crystal element 120 is mounted in the first region R1 which is accommodated in the recess K1 and which faces the lid of the inner surface of the recess K1. The temperature sensor 130 is mounted in the second region R2 housed in the recess K1 and facing the lid side of the inner surface of the recess K1, and detects the temperature on the surface (main surface 132a) on the second region R2 side Do.

  Here, the case where the temperature of the external environment of the crystal unit 1 changes will be considered. In such a case, generally, the temperature change of the external environment is likely to be transmitted to the quartz crystal element 120 via the bottom of the recess K1 (the first insulating layer 110a and the second insulating layer 110b).

  As the reason, for example, the following can be mentioned. The inside of the recess K 1 is vacuum (strictly reduced pressure), and theoretically, the temperature change of the external environment is not transmitted to the crystal element 120 via the space around the crystal element 120. Alternatively, even if the gas is sealed in the recess K1, the thermal conductivity of the gas and the package 110 is relatively low. Therefore, the temperature change of the external environment causes the quartz element 120 to pass through the space around the quartz element 120. It is hard to tell On the other hand, since the quartz crystal element 120 is mounted on the bottom (first region R1) of the recess K1 (joined to the first region R1 by the conductive adhesive 150), the temperature change of the bottom of the recess K1 easily influenced. Also, in general, the conductor (metal) has a thermal conductivity higher than that of the insulator. On the other hand, a conductive path is formed from the first external connection electrode terminal G1 to the excitation electrode 122 of the crystal element 120 via the electrode pad 111. Also by this, the temperature of the quartz crystal element 120 is susceptible to the temperature of the electrode pad 111 (the bottom of the recess K1).

  On the other hand, unlike the present embodiment, by using the temperature sensor 130 for detecting the temperature on the main surface 132a on the bottom (second region R2) side of the recess K1, the aspect of detecting the temperature over the entire chip of the temperature sensor is compared. As a result, the detected temperature easily follows the temperature at the bottom of the recess K1. Since the temperature sensor 130 is mounted (bonded) to the bottom of the recess K1, the temperature change at the bottom of the recess K1 is easily transmitted to the main surface 132a, and the detection temperature more easily follows the temperature of the recess K1. Therefore, the detected temperature can easily follow the temperature of the crystal element 120, and temperature compensation based on the detected temperature can be performed with high accuracy.

  Further, in the present embodiment, the temperature sensor 130 is located on the side of the sensor substrate (semiconductor substrate 132) mounted on the surface facing the second region R2 and on the side of the second region R2 of the semiconductor substrate 132. And a temperature measuring unit (diode 134) whose dynamic characteristics change with temperature.

  In another aspect, the temperature sensor 130 includes the semiconductor substrate 132 surface-mounted opposite to the second region R2. The main surface 132a on the second region R2 side of the semiconductor substrate 132 includes a p-type region 132p and an n-type region 132n constituting the diode 134.

  That is, the temperature sensor 130 is a bare chip or a WLP (wafer level package) type chip or the like. Therefore, for example, the crystal oscillator 1 can be miniaturized. Also, for example, as compared with the case where the package is provided, the diode 134 (temperature measuring unit) is directly affected by the temperature of the bottom of the recess K1, and the sensitivity of the temperature sensor 130 is improved. .

  Further, in the present embodiment, the quartz crystal element 120 is supported only at one end side in the first direction (D1-axis direction) parallel to the bottom surface (second region R2) of the recess K1. The semiconductor substrate 132 includes a first layer (n-type layer 133n) whose partial region constitutes one of the p-type region 132p and the n-type region 132n (the n-type region 132n in the illustrated example), and the partial region A second layer (p-type layer 133p) constituting the other of the p-type region and the n-type region (p-type region 132p in the illustrated example) by being positioned on the first layer in a region different from Have. At least a part (all in the present embodiment) of the second layer is located on one side or the other side of the supporting position (electrode pad 111) of the quartz crystal element 120 in the first direction.

  Here, since the bottom of the recess K1 (the first insulating layer 110a and the second insulating layer 110b) holds only one end side of the quartz crystal element 120, the electrode pad 111 is positioned only on one side in the D1 axis direction. ing. That is, the area of the conductor susceptible to the temperature change of the external environment through the first external connection electrode terminal G1 is secured on only one side in the D1 axis direction. Therefore, the temperature change at the bottom of the recess K1 tends to progress from the electrode pad 111 side.

  It is assumed that the thickness of the p-type layer 133p is equal to the thickness of the semiconductor substrate 132 and the pn junction surface is only a plane (boundary portion 132b) substantially orthogonal to the D1 axis, unlike the present embodiment (this Such embodiments are also included in the technology according to the present disclosure. In this case, when the temperature change at the bottom of the recess K1 progresses along the D1 axis, when the temperature change reaches the boundary 132b, the change in the forward characteristics appears, and thus, the detected temperature relatively rapidly Will change. The change in the detected temperature may not necessarily reflect the temperature change of the crystal element 120.

  However, when the p-type layer 133p is located on the n-type layer 133n, the boundary surface 133b extends in the D1-axis direction. Then, the change of the forward characteristic in the boundary surface 133b appears little by little in the process in which the temperature change of the bottom of the recess K1 progresses in the D1 axis direction below the boundary surface 133b. As a result, rapid changes in detected temperature are mitigated. Note that, as described above, when the boundary surface 133b is at a position away from the main surface 132a (the cathode terminal 131a and the anode terminal 131b), the current exceeding the boundary surface 133b decreases. Therefore, the effect is improved as the p-type layer 133p (second layer) is thinner.

  Further, in the present embodiment, the first region R1 is the upper surface of the pedestal portion 118 located on the bottom surface (upper surface of the first insulating layer 110a) of the recess K1. The second region R2 is the bottom surface of the recess K1. The height from the bottom surface of the recess K 1 of the pedestal portion 118 (the thickness of the second insulating layer 110 b) is smaller than the height from the pedestal portion 118 to the lid 140.

  In this case, for example, since the second insulating layer 110b is relatively thin, the temperature of the first region R1 and the temperature of the second region R2 easily follow each other. As a result, the temperature of the quartz crystal element 120 can be brought close to the temperature detected by the temperature sensor.

  In the above embodiment, the crystal unit 1 is an example of a piezoelectric unit. The quartz crystal element 120 is an example of a piezoelectric element. The semiconductor substrate 132 is an example of a sensor substrate. The diode 134 is an example of a temperature measuring unit. The D1 axis direction is an example of a first direction. The n-type layer 133 n is an example of a first layer. The p-type layer 133p is an example of a second layer.

Second Embodiment
FIG. 5A is a plan view showing the main configuration of the crystal unit 51 according to the second embodiment. FIG.5 (b) is sectional drawing in the Vb-Vb line | wire of FIG. 5 (a).

  Also in the second embodiment, as in the first embodiment, the quartz crystal element 120 and the temperature sensor 130 are a first region R51 and a second region R52 facing the lid 140 among the inner surfaces of the recess K51 of the package 53. Has been implemented. And the temperature sensor 130 detects temperature in the surface (main surface 132a (refer FIG. 4)) by the side of 2nd area | region R52.

  Therefore, the same effect as that of the first embodiment is exhibited. For example, the temperature change of the external environment is easily transmitted to the quartz crystal element 120 through the bottom of the concave portion K51, the temperature of the bottom of the concave portion K51 can be accurately detected by the temperature sensor 130, and thus the temperature of the quartz crystal element 120 Can be accurately detected.

  However, in the first embodiment, the first region R1 is provided at a position higher than the second region R2, whereas in the present embodiment, the first region R1 and the second region R2 are the same. Located at the height. That is, in the present embodiment, the pedestal portion 118 is not provided, and the first region R1 and the second region R2 are both formed of the bottom surface of the recess K51 and are flush.

  In another aspect, in the first embodiment, the crystal element 120 and the temperature sensor 130 are disposed in a stacked manner, whereas in the present embodiment, the crystal element 120 and the temperature sensor 130 are disposed in a planar manner. ing.

  As described above, when the first region R1 and the second region R2 are flush, for example, the temperatures of the first region R1 and the second region R2 approximate each other as compared with the first embodiment. As described above, since the quartz crystal element 120 is susceptible to the temperature change of the first region R1 and the temperature sensor 130 detects the temperature on the surface on the second region R2 side, the temperature sensor 130 detects the temperature of the quartz crystal element 120 It can detect accurately.

  The package 53 having the flush first region R1 and the second region R2 as described above is constituted of, for example, a first insulating layer 53a and a second insulating layer 53b stacked thereon. These insulating layers are the same as the insulating layers (110a to 110c) of the first embodiment.

  The relative position of the crystal element 120 and the temperature sensor 130 in plan view may be set appropriately. In the illustrated example, the substantially rectangular temperature sensor 130 is disposed such that the long sides are parallel to the substantially rectangular crystal element 120. By such an arrangement, for example, the crystal unit 51 can be miniaturized.

  In the illustrated example, the length of the temperature sensor 130 (here, the length of the long side) is the length of the quartz crystal element 120 in the direction from the fixed end to the free end of the quartz crystal element 120 (D1 axis direction). Here, it is shorter than the long side length). The center of the temperature sensor 130 (the figure center of gravity) is located closer to the connection electrode 123 (the electrode pad 111) than the center of the crystal element 120 (the figure center of gravity).

  In another viewpoint, the piezoelectric element (quartz element 120) is supported only at one end side (the negative side in the D1-axis direction) of the first direction in a plan view of the recess K1, and the supporting position thereof is It is located in the said one end side of the 1st direction rather than the center. Further, the center of the temperature sensor 130 is located closer to the one end side in the first direction than the center of the package 53 in plan view of the recess K1.

  As understood from the above description, when the temperature of the external environment changes, the temperature of the crystal element 120 is susceptible to the temperature of the electrode pad 111. Therefore, as described above, when the temperature sensor 130 is positioned on the electrode pad 111 side, the detected temperature can be easily made to follow the temperature on the electrode pad 111 side. There is a time delay from when the temperature change occurs in the electrode pad 111 until the temperature change is transmitted to the quartz crystal substrate 121. Depending on the length of the time delay and the sensitivity of the temperature sensor 130, this configuration is used. Thus, the detected temperature can be brought close to the temperature of the quartz substrate 121.

(Modification)
Hereinafter, various modifications will be described. The modification may be applied to any of the first and second embodiments, but for convenience, the code of the first embodiment is preferentially used.

(Modified example concerning arrangement position of temperature sensor)
FIG. 6A is a plan view showing the main configuration of a crystal unit 201 according to a modification.

  The quartz oscillator 201 basically differs from the first embodiment only in the position of the temperature sensor 130. Incidentally, in accordance with the difference in the position of the temperature sensor 130, the arrangement of the bonding pad 115 and the shape of the sensor wiring pattern 116 are also different from those of the embodiment. Further, the position and / or shape of the sensor recess K3 may be different from that of the embodiment. However, these explanations are omitted.

  In the arrangement of the temperature sensor 130, first, the orientation in plan view differs from that of the embodiment by 90 °. That is, while the quartz crystal element 120 is supported only at one end side in the first direction (D1 axis direction) parallel to the bottom surface of the recess K1, the p-type region 132p and the n-type region 132n in a plan view of the semiconductor substrate 132 At least a part (all in the illustrated example) of the boundary portion 132b of the crystal element 120 is located on one side or the other side of the supporting position (electrode pad 111) of the quartz crystal element 120 in the first direction It extends along.

  In the description of the embodiment, when the temperature change at the bottom of the recess K1 progresses from the electrode pad 111 side, if the temperature change reaches the boundary 132b, there is a possibility that an abrupt change in the detected temperature may occur. The On the other hand, in the crystal unit 201 of this modification, since the boundary portion 132b is along the D1 axis, the change of the forward characteristic gradually occurs with the progress of the temperature change in the D1 axis direction, Sudden changes in detected temperature are mitigated.

  When the boundary portion 132 b extends in the first direction, the boundary portion 132 b is not necessarily parallel to the first direction. For example, the boundary 132 b may be inclined in the first direction at an angle of 10 ° or less.

  Further, in the present modification, as in the second embodiment, in plan view of the recess K1, the center CP2 (geometric center of gravity) of the temperature sensor 130 is the center CP1 of the package 110 (geometric center of gravity. Center line CL1 and center line CL2 And the electrode pad 111 in the direction of the D1 axis. This effect is as described in the second embodiment.

  The configuration of moving the temperature sensor 130 toward the electrode pad 111 is also applied to the case where the alignment direction of the p-type region 132p and the n-type region 132n is the D1 axis direction or another direction as in the embodiment. Good.

(Modified example concerning the configuration of the temperature sensor)
Below, the modification which concerns on the structure of a temperature sensor is shown. In addition, although direction of the temperature sensor with respect to D1 axis | shaft and D2 axis is made to be the same as that of embodiment for convenience, you may be made to be the same as that of the modification of Fig.6 (a).

  As described above, the positional relationship between the n-type semiconductor and the p-type semiconductor of the embodiment may be reversed. Such a modification is performed on the temperature sensor 203 according to the modification shown in FIG. 6 (b). That is, in this modification, the n-type layer 133 n is provided in a partial region of the p-type layer 133 p. In the various modifications described below, the positional relationship between the n-type semiconductor and the p-type semiconductor in the vertical and / or lateral directions may be reversed.

  Further, in the modification of FIG. 6B, the boundary 132b between the n-type region 132n and the p-type region 132p is formed so as to surround the n-type region 132n in plan view. A portion of the boundary portion 132b along the D1-axis direction is, for example, similar to the boundary portion 132b of FIG. 6A, when the temperature change at the bottom of the recess K1 proceeds in the D1-axis direction, the detected temperature The effect of suppressing the rapid change of the

  However, as for the above effect, as in the modified example of FIG. 6A, a portion having a large influence on the function as a diode in the pn junction surface is larger along the D1 axis. As such an aspect, for example, as shown in FIG. 6A, in a plan view of the semiconductor substrate 132, a portion (boundary portion 132b) along the first direction (D1-axis direction) in the pn junction surface And / or a direction (D2-axis direction) in which 80% or more of the p-type region 132p is orthogonal to the first direction with respect to the center line CL1 of the semiconductor substrate 132 parallel to the first direction (D1-axis direction) And at least 80% of the n-type region 132n is located on the other side of the direction (D2-axis direction) orthogonal to the first direction.

  A temperature sensor 205 according to a modification of FIG. 6C has a so-called well. In the illustrated example, an n-type well 209 is formed in a p-type semiconductor substrate 207, and a p-type layer 210 is formed in the well 209. The well 209 is an example of a first layer, and the layer 210 is an example of a second layer. The variation of providing such a well may be applied to any of the embodiment and other variations.

  FIG. 7A is a cross-sectional view of a temperature sensor 211 according to a modification. FIG. 7B is a plan view showing the configuration of the semiconductor substrate 213 of the temperature sensor 211. As shown in FIG.

  As in the embodiment, the temperature sensor 211 has a semiconductor substrate 213 including a diode 215, and the semiconductor substrate 213 is mounted on the surface in the second region R2. However, the temperature sensor 211 is not a bare chip but a so-called WLP chip.

  That is, the temperature sensor 211 has the rewiring layer 217 on the semiconductor substrate 213, the anode terminal 131b and the cathode terminal 131a. Although the rewiring layer 217 is not particularly designated by a reference numeral, for example, an insulating layer and a conductor layer are stacked in an appropriate number, and the terminal is exposed at the top. Solder bumps or the like may be provided on the terminals.

  By providing the rewiring layer 217 in this manner, for example, the arrangement position of the anode terminal 131 b and the cathode terminal 131 a in the temperature sensor 130 (and the arrangement position of the n-type region 132 n and the p-type region 132 p) The degree of freedom in designing the arrangement position of the terminal in the temperature sensor 130 and the positional relationship between them is improved.

  Therefore, for example, both ends of the semiconductor substrate 213 may be joined to the package 110 while the anode terminal 131b (p-type region 132p) is positioned at the center of the semiconductor substrate 132 (n-type region 132n).

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

  For example, the temperature sensor that detects the temperature on the surface is not limited to one having a diode. In addition, a temperature sensor (a bare chip, a WLP type chip, or a chip similar to these) having a sensor substrate mounted on the second region of the package and a temperature measuring portion located on the second region side of the sensor substrate also has a diode. It is not limited to things. For example, the temperature sensor may have an appropriate insulating substrate and a resistor disposed on the main surface of the insulating substrate on the second region side, and may utilize a change in resistance with respect to a temperature change.

  In the bare chip, the WLP type chip, or the like, the sensor substrate may be provided with an insulating layer and / or a conductor layer on the side surface and the back surface (opposite to the temperature measuring portion). In other words, the semiconductor substrate may not necessarily be partially exposed.

  In the case where the temperature sensor includes a diode, the temperature sensor may be packaged. Even in this case, for example, the semiconductor substrate is disposed in the sealing member such that the semiconductor substrate is moved to the second region side in the sealing member, or the surface on which the diode is formed is directed to the second region side. It is possible to realize a configuration in which it can be said that the temperature is detected on the surface by increasing the thermal conductivity of the portion of the stopper member located between the semiconductor substrate and the second region. Also, in the embodiment, the temperature sensor included only one diode. However, the temperature sensor may include a plurality of diodes connected to one another.

  Although a diode having a pn junction is exemplified as the diode, the diode may have a junction surface (boundary portion, interface) other than the pn junction like a PIN diode. In the PIN diode, the boundary between the p-type region and the n-type region (the boundary surface between the first layer and the second layer) is an i-type region (i-type layer).

  The diode may be configured to function as another element. For example, the temperature sensor may include a transistor, and a part of the transistor may function as a diode, for example, when the base and the collector are shorted by the wiring of the temperature sensor or the wiring of the package.

  The diode is not limited to a planar structure in which a p-type region and an n-type region are formed on the main surface of the semiconductor substrate, but a p-type layer and an n-type layer are stacked and a current flows in the stacking direction. It may be. Even in this case, it can be said that the temperature is detected on the surface on the second area side if the diode is provided on the surface on the second area side in the temperature sensor.

Moreover, the diode may have an appropriate layer etc. in addition to having been shown in the embodiment. For example, an oxide film (for example, a SiO ₂ film), a gate ring, a passivation film, and the like located on the semiconductor substrate may be appropriately provided.

  DESCRIPTION OF SYMBOLS 1: Crystal oscillator (piezoelectric oscillator) 110: Package 120: Crystal element (piezoelectric element) 130: Temperature sensor 140: Lid, K1: recessed portion R1: first area R2: second area

Claims (10)

A package having a recess,
A lid which seals the inside of the recess by closing the opening of the recess;
A piezoelectric element housed in the recess and mounted in a first region of the inner surface of the recess facing the lid;
A temperature sensor for detecting a temperature on the surface of the second region, which is accommodated in the recess and is mounted in a second region of the inner surface of the recess facing the lid;
Piezoelectric vibrator that has. The temperature sensor is
A sensor substrate surface-mounted to face the second region;
The piezoelectric vibrator according to claim 1, further comprising: a temperature measurement unit positioned on the second region side of the sensor substrate, the electrical characteristic changing according to a temperature. The temperature sensor has a semiconductor substrate surface-mounted to face the second region,
3. The piezoelectric vibrator according to claim 1, wherein the main surface on the second region side of the semiconductor substrate includes a p-type region and an n-type region constituting a diode. The piezoelectric element is supported only at one end side in a first direction parallel to the bottom surface of the recess,
The semiconductor substrate is
A first layer in which a part of the region constitutes one of the p-type region and the n-type region;
And a second layer constituting the other of the p-type region and the n-type region by being located on the first layer in a region different from the partial region,
The piezoelectric vibrator according to claim 3, wherein at least a part of the second layer is located on one side or the other side of the first direction with respect to the support position of the piezoelectric element. The piezoelectric element is supported only at one end side in a first direction parallel to the bottom surface of the recess,
In a plan view of the semiconductor substrate, at least a part of the boundary between the p-type region and the n-type region is located on one side or the other side in the first direction with respect to the support position of the piezoelectric element. The piezoelectric vibrator according to claim 3, which extends along the first direction. In a plan view of the semiconductor substrate, at least 80% of the p-type region is located on one side in a direction orthogonal to the first direction with respect to the portion of the boundary extending along the first direction. The piezoelectric vibrator according to claim 5, wherein 80% or more of the n-type region is located on the other side of the direction orthogonal to the first direction. In a plan view of the recess, the piezoelectric element is supported only at one end side in the first direction, and the support position is located at the one end side in the first direction with respect to the center of the package. ,
The piezoelectric vibrator according to any one of claims 1 to 6, wherein a center of the temperature sensor is located closer to the one end in the first direction than a center of the package in a plan view of the recess. The first region is an upper surface of a pedestal located on the bottom of the recess,
The second region is a bottom surface of the recess,
The piezoelectric vibrator according to any one of claims 1 to 7, wherein a height from a bottom surface of the recess of the pedestal is lower than a height from the pedestal to the lid. The piezoelectric vibrator according to any one of claims 1 to 7, wherein the first area and the second area are flush with each other. A package having a recess,
A lid which seals the inside of the recess by closing the opening of the recess;
A piezoelectric element housed in the recess and mounted in a first region of the inner surface of the recess facing the lid;
A temperature sensor housed in the recess and mounted in a second region of the inner surface of the recess facing the lid;
And have
The temperature sensor has a semiconductor substrate surface-mounted to face the second region,
The main surface on the second region side of the semiconductor substrate includes a p-type region and an n-type region constituting a diode.

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