JP2019211229A - Temperature sensor and piezoelectric vibration device including the same - Google Patents

Abstract

To provide a temperature sensor capable of improving adhesion between an electrode layer and a resistive layer, and a piezoelectric vibration device including the same.SOLUTION: A temperature sensor 10 comprises a resistive layer 14 formed of a thermistor material and a pair of electrode layers 12, 12 formed to face each other across the resistive layer 14 on an insulating substrate 11. An interface layer 13 is interposed between the resistive layer 14 and the electrode layer 12. The electrode layer 12 is an Au layer, and the interface layer 13 is a Ti layer or a Cr layer.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a temperature sensor and a piezoelectric vibration device including the same.

  Conventionally, a temperature sensor is known in which an insulating substrate is provided with a resistance layer formed of a thermistor material and a pair of electrode layers formed opposite to each other with the resistance layer interposed therebetween (for example, a patent) Reference 1). The resistance layer is formed of, for example, a nitride material, and the electrode layer is formed of, for example, an Au layer made of Au (gold).

JP 2018-36245 A

  In the temperature sensor as described above, it is required to form the electrode layer and the resistance layer as thin as possible from the viewpoint of reducing the thickness. However, when the electrode layer and the resistance layer are formed thin, the adhesion between the electrode layer and the resistance layer may be reduced, and there is a concern that peeling occurs at the interface between the electrode layer and the resistance layer. In addition, for example, an etching solution for forming the electrode layer by metal etching may enter the interface between the electrode layer and the resistance layer, which causes a decrease in adhesion between the electrode layer and the resistance layer. there is a possibility.

  The present invention has been made in consideration of the above-described circumstances, and provides a temperature sensor capable of improving adhesion between an electrode layer and a resistance layer, and a piezoelectric vibration device including the temperature sensor. For the purpose.

  In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention is a temperature sensor comprising an insulating substrate provided with a resistance layer formed of a thermistor material and a pair of electrode layers formed facing each other across the resistance layer in plan view. An interface layer is interposed between the resistance layer and the electrode layer.

  According to the above configuration, the adhesion between the electrode layer and the resistance layer, more specifically, the adhesion between the electrode layer and the interface layer, and the resistance layer, compared to the case where the electrode layer and the resistance layer are directly laminated. The adhesion between the electrode layer and the interface layer can be improved, and the peeling of the electrode layer and the resistance layer from the insulating substrate can be suppressed.

  Here, when the electrode layer and the resistance layer are directly laminated, the etching solution for forming the electrode layer by metal etching may invade the interface between the electrode layer and the resistance layer. There is a possibility to invite. However, in the above configuration, since the interface layer is interposed between the electrode layer and the resistance layer, it is possible to suppress a decrease in adhesion between the electrode layer and the resistance layer due to the penetration of the etching solution.

  In the temperature sensor configured as described above, it is preferable that the electrode layer is an Au layer and the interface layer is a Ti layer or a Cr layer. According to this configuration, when the electrode layer made of the Au layer and the resistance layer are directly laminated, the adhesion between the two may be lowered, but the interface layer made of the Ti layer or the Cr layer is interposed therebetween. As a result, the adhesion between the electrode layer and the resistance layer can be improved. That is, since the adhesion between the electrode layer made of the Au layer and the interface layer made of the Ti layer or the Cr layer is relatively good, the electrode layer and the resistance layer can be used even when the Au layer is used as the electrode layer. The adhesion between the two can be improved.

  In the temperature sensor having the above configuration, the thermistor material is preferably a chromium compound (CrNO) containing oxygen and nitrogen as components. According to this configuration, a larger B constant can be obtained by using CrNO as the thermistor material of the resistance layer. Thereby, the sensing performance of the temperature sensor can be improved.

  In the temperature sensor configured as described above, the electrode layer is preferably formed in a comb shape. According to this configuration, it is possible to ensure a longer path length of the resistance layer by forming the electrode layer in a comb shape. Thereby, even if it is a very small temperature sensor, a bigger B constant can be obtained and the sensing performance of a temperature sensor can be improved.

  In the temperature sensor having the above configuration, it is preferable that the electrode layer, the interface layer, and the resistance layer are stacked in this order on the surface of the insulating substrate. According to this configuration, the electrode layer can be protected by covering the electrode layer with the interface layer and the resistance layer, and dust and the like can be prevented from adhering to the electrode layer.

  According to another aspect of the present invention, there is provided a piezoelectric vibration device including the temperature sensor configured as described above. According to this piezoelectric vibration device, the same effect as the temperature sensor having the above-described configuration can be obtained. Moreover, it is possible to reduce the height of the piezoelectric vibration device with a temperature sensor.

  According to the present invention, the adhesion between the electrode layer and the resistance layer, more specifically, the adhesion between the electrode layer and the interface layer, and the resistance layer, compared with the case where the electrode layer and the resistance layer are directly laminated. The adhesion between the electrode layer and the interface layer can be improved, and the peeling of the electrode layer and the resistance layer from the insulating substrate can be suppressed.

FIG. 1 is a schematic front view schematically showing a temperature sensor according to the present embodiment. FIG. 2 is a schematic plan view of the first main surface side of the temperature sensor. FIG. 3 is a schematic plan view of the second main surface side of the temperature sensor. 4 is a schematic cross-sectional view taken along line X1-X1 of FIG. FIG. 5 is a schematic sectional view taken along line X2-X2 of FIG. FIG. 6 is a schematic front view schematically showing a crystal resonator including the temperature sensor according to the present embodiment. FIG. 7 is a schematic plan view of the first main surface side of the first sealing member of the crystal resonator. FIG. 8 is a schematic plan view of the second main surface side of the first sealing member of the crystal resonator. FIG. 9 is a schematic plan view of the first main surface side of the crystal diaphragm of the crystal resonator. FIG. 10 is a schematic plan view of the second main surface side of the crystal diaphragm of the crystal resonator. FIG. 11 is a schematic plan view of the first main surface side of the second sealing member of the crystal resonator. FIG. 12 is a schematic plan view of the second main surface side of the second sealing member of the crystal resonator. FIG. 13 is a schematic plan view of the second main surface side of the temperature sensor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 show an example of the temperature sensor 10 according to the present embodiment, and FIGS. 6 to 13 show an example of the crystal resonator 100 according to the present embodiment.

  First, the temperature sensor 10 according to the present embodiment will be described with reference to FIGS. In the temperature sensor 10, a pair of electrode layers (electrode films) 12, 12, an interface layer (interface film) 13, and a resistance layer (resistance film) 14 formed of a thermistor material are stacked on an insulating substrate 11. It is configured as a thin film thermistor. In the present embodiment, the electrode layer 12, the interface layer 13, and the resistance layer 14 are formed over substantially the entire first main surface 11 a of the substantially rectangular insulating substrate 11 in plan view. In addition, electrode layers 15 are formed on both ends in the longitudinal direction of the second main surface 11 b of the insulating substrate 11.

  The insulating substrate 11 is a substantially rectangular parallelepiped substrate made of, for example, glass. The first main surface 11a of the insulating substrate 11 is formed as a flat surface, and the first main surface 11a is a surface on which the electrode layers 12 and the like are stacked. The insulating substrate 11 may be formed of other materials (for example, quartz) as long as it has electrical insulation performance.

  Through holes 11c and 11c penetrating between the first main surface 11a and the second main surface 11b are formed at two positions on the diagonal of the four corners of the insulating substrate 11. In this case, the through-holes 11c are provided at the end in the A2 direction and the end in the B1 direction of the insulating substrate 11, and the end in the A1 direction and the end in the B2 direction, respectively. In each through hole 11c, a through electrode is formed along the inner wall surface of the through hole 11c for conducting the electrodes formed on the first main surface 11a and the second main surface 11b. Moreover, the center part of each through-hole 11c turns into a hollow penetration part penetrated between the 1st main surface 11a and the 2nd main surface 11b. The electrode layer 12 on the first main surface 11a side and the electrode layer 15 on the second main surface 11b side are electrically connected by the through electrode of the through hole 11c. Note that the through electrode is not limited to having a through part, and may be formed in a solid state without a through part.

  A pair of electrode layers 12, 12 are formed on the first main surface 11 a of the insulating substrate 11 with a predetermined facing interval. The pair of electrode layers 12 and 12 are disposed to face each other with the resistance layer 14 interposed therebetween in a plan view. Each electrode layer 12 is a layer formed by physical vapor deposition on the first main surface 11a of the insulating substrate 11 (for example, a Ti layer) and physical vapor deposition on the ground layer. It is formed from the formed electrode layer (for example, Au layer). The base layer is a Ti layer made of Ti (titanium), for example, and the electrode layer is an Au layer made of Au (gold), for example. Note that an electrode layer (Au layer) may be formed on the first main surface 11a of the insulating substrate 11 without using the underlayer.

  In the present embodiment, each electrode layer 12 is formed in a comb shape in plan view as shown in FIG. Specifically, each electrode layer 12 has a configuration in which a large number of branch portions 12 b extend in parallel from a base portion 12 a provided along the long side direction of the insulating substrate 11. The branch portions 12b of one electrode layer 12 and the branch portions 12b of the other electrode layer 12 are arranged alternately with a predetermined gap L1 (FIG. 5) so as not to contact each other. The resistance layer 14 is filled in the gap L1 between the branch portions 12b and 12b, and the resistance layer 14 is provided between the pair of electrode layers 12 and 12 facing each other. Such a comb-shaped electrode layer 12 is formed by metal etching, for example.

  The resistance layer 14 is formed of a PVD film formed on the interface layer 13 by physical vapor deposition. More specifically, the resistance layer 14 can be formed as a reactive sputtered film formed by reactive DC magnetron sputtering or reactive RF magnetron sputtering. The resistance layer 14 is formed of a thermistor material having a predetermined temperature characteristic. For example, the resistance layer 14 is formed of a material having a characteristic (NTC thermistor characteristic) in which the resistance value decreases approximately proportionally as the temperature rises. ing. As such a thermistor material, for example, CrNO (a chromium compound containing oxygen and nitrogen as components) is employed. The thermistor material is not limited to CrNO, and may be a nitride semiconductor, an oxide semiconductor, or the like. For example, CrN (chromium nitride), AlN (aluminum nitride), SiN (silicon nitride), ZrN (zirconium nitride), etc. It may be.

  Then, the resistance layer 14 sandwiched between the pair of electrode layers 12 and 12 has an end portion in the A1 direction and an end portion in the B1 direction of the insulating substrate 11 and an end portion in the A1 direction and the B2 direction in plan view. It is formed in a meandering state up to the end. In addition, the resistance layer 14 sandwiched between the pair of electrode layers 12 and 12 is formed with a constant width L2 (FIG. 5) and a single path, and the path length W of the resistance layer 14 is The total length of the pair of electrode layers 12 and 12 facing each other is obtained. The width L2 of the resistance layer 14 is smaller than the gap L1 between the electrode layers 12 described above by the thickness of the interface layer 13.

  In the present embodiment, the interface layer 13 having a predetermined thickness (for example, 4 to 5 nm) is interposed between the electrode layer 12 and the resistance layer 14 in a sectional view. As shown in FIGS. 4 and 5, the electrode layer 12, the interface layer 13, and the resistance layer 14 are stacked in this order on the first main surface 11 a of the insulating substrate 11. Specifically, an electrode layer 12 formed in a comb shape in plan view is formed on the first main surface 11a of the insulating substrate 11, and the electrode layer 12 is formed on the first main surface 11a. And a portion where the electrode layer 12 is not formed. And in the location where the electrode layer 12 is formed on the 1st main surface 11a of the insulating substrate 11, the interface layer 13 is laminated | stacked on the electrode layer 12, and the resistance layer 14 is laminated | stacked on the interface layer 13. Yes. On the other hand, at a location where the electrode layer 12 is not formed on the first main surface 11a of the insulating substrate 11, the interface layer 13 is stacked on the first main surface 11a, and the resistance layer 14 is stacked on the interface layer 13 Has been. The interface layer 13 is formed from a PVD film formed by physical vapor deposition. In the present embodiment, the interface layer 13 is formed by a Ti layer made of Ti (titanium). 4 and 5, the thicknesses of the electrode layer 12, the interface layer 13, and the resistance layer 14 are exaggerated.

  According to the temperature sensor 10 having the above-described configuration, the path length W of the resistance layer 14 sandwiched between the pair of electrode layers 12 and 12 can be ensured to be longer. Also, a larger B constant can be obtained. Specifically, the resistance value of the temperature sensor 10 is proportional to the width L <b> 2 of the resistance layer 14 and inversely proportional to the path length W of the resistance layer 14. For this reason, the resistance value of the temperature sensor 10 having a larger B constant can be reduced by increasing the path length W of the resistance layer 14 and further reducing the width L2 of the resistance layer 14. Thereby, the sensing performance of the temperature sensor 10 can be improved. Although it is possible to improve the sensing performance by making the path length W of the resistance layer 14 longer by forming the temperature sensor 10 on substantially the entire first main surface 11a of the insulating substrate 11, the insulating substrate 11 The temperature sensor 10 may be formed only in a partial region of the first main surface 11a.

  In the present embodiment, since the interface layer 13 is interposed between the electrode layer 12 and the resistance layer 14, the electrode layer 12 and the resistance layer 14 are compared with the case where the electrode layer 12 and the resistance layer 14 are directly laminated. In particular, the adhesion between the electrode layer 12 and the interface layer 13 and the adhesion between the resistance layer 14 and the interface layer 13 can be improved. Separation from the insulating substrate 11 can be suppressed.

  Here, in the case where the electrode layer 12 and the resistance layer 14 are directly laminated, the etching solution for forming the comb-shaped electrode layer 12 by metal etching may enter the interface between the electrode layer 12 and the resistance layer 14. There is a possibility that the adhesion may be lowered. However, in this embodiment, since the interface layer 13 is interposed between the electrode layer 12 and the resistance layer 14, the adhesion between the electrode layer 12 and the resistance layer 14 is reduced due to the penetration of the etching solution. Can be suppressed.

  Further, when the electrode layer 12 made of the Au layer and the resistance layer 14 are directly laminated, the adhesion between them may be lowered. However, in the present embodiment, the adhesion between the electrode layer 12 and the resistance layer 14 can be improved by interposing the interface layer 13 made of a Ti layer therebetween. That is, since the adhesiveness between the electrode layer 12 made of the Au layer and the interface layer 13 made of the Ti layer is relatively good, even if the Au layer is used as the electrode layer 12, the electrode layer 12 and the resistance layer The adhesion between the layer 14 can be improved.

  Here, a Cr layer made of Cr (chromium) may be used as the interface layer 13. Also in this case, since the adhesion between the electrode layer 12 made of the Au layer and the interface layer 13 made of the Cr layer is relatively good, the electrode layer can be used even when the Au layer is used as the electrode layer 12. The adhesion between the resistor 12 and the resistance layer 14 can be improved. Note that it is preferable to form the interface layer 13 with a Ti layer from the viewpoint of suppressing erosion by the etching solution.

  In the present embodiment, since CrNO is used as the thermistor material of the resistance layer 14, a larger B constant can be obtained. Thereby, the sensing performance of the temperature sensor 10 can be improved.

  In the present embodiment, the electrode layer 12, the interface layer 13, and the resistance layer 14 are laminated in this order on the first main surface 11 a of the insulating substrate 11, so that the electrode layer is formed by the interface layer 13 and the resistance layer 14. By covering 12, the electrode layer 12 can be protected, and adhesion of dust and the like to the electrode layer 12 can be prevented. Note that the resistance layer 14, the interface layer 13, and the electrode layer 12 may be stacked in this order on the first main surface 11 a of the insulating substrate 11. In this case, the resistance layer 14 is formed over substantially the entire first main surface 11 a of the insulating substrate 11, the interface layer 13 is formed on the resistance layer 14, and the comb-like shape is formed on the interface layer 13. The electrode layer 12 may be formed.

  Next, the crystal unit 100 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 6, the crystal unit 100 includes a crystal diaphragm 102, a first sealing member 103, a second sealing member 104, and the temperature sensor 10 described above. In the crystal unit 100, the quartz diaphragm 102 and the first sealing member 103 are joined, and the quartz diaphragm 102 and the second sealing member 104 are joined, whereby a package 112 having a substantially rectangular parallelepiped sandwich structure. Is configured.

  In the quartz diaphragm 102, a first excitation electrode 221 is formed on a first main surface 211 that is one main surface, and a second excitation electrode 222 is formed on a second main surface 212 that is the other main surface. In the crystal unit 100, the first sealing member 103 and the second sealing member 104 are bonded to both main surfaces (first main surface 211 and second main surface 212) of the crystal vibrating plate 102, respectively. As a result, an internal space 113 of the package 112 is formed, and the vibrating portion 122 (see FIGS. 9 and 10) including the first excitation electrode 221 and the second excitation electrode 222 is hermetically sealed in the internal space 113.

  In the present embodiment, the crystal unit 100 is configured as a crystal unit with a temperature sensor including the temperature sensor 10. That is, the package 112 of the crystal unit 100 is provided with the temperature sensor 10 for detecting the temperature of the vibrating unit 122 (the temperature of the internal space 113). The temperature sensor 10 has substantially the same configuration as the above embodiment (see FIGS. 1 to 5). On the other hand, in the present embodiment, as shown in FIG. 13, connection joint patterns 16 and 17 are formed in the four corner regions of the second main surface 11 b of the insulating substrate 11 of the temperature sensor 10. The connection bonding patterns 16 and 17 are formed by laminating a base film formed by physical vapor deposition on the second main surface 11b of the insulating substrate 11, and by physical vapor deposition on the base film. And a bonding film. In this embodiment, Ti (or Cr) is used for the base film, and Au is used for the bonding film. The connecting bonding patterns 16 and 17 can be formed by the same process as the electrode layer 12 on the first main surface 11a of the insulating substrate 11.

  The connection bonding patterns 16 are provided at two positions located on the diagonal line among the four corner areas of the second main surface 11b of the insulating substrate 11, and the remaining remaining positions located on the diagonal line among the four corner areas. Connection patterns 17 for connection are provided at two locations. The connection bonding pattern 16 is formed around the through hole 11c, and is electrically connected to the electrode layer 12 formed on the first main surface 11a of the insulating substrate 11 through the through electrode. The joint pattern 16 for connection is provided in the area | region on the A2 direction side and B1 direction side of the 2nd main surface 11b of the insulating substrate 11, and the area | region on the A1 direction side and B2 direction side, respectively. The joint pattern 17 for connection is provided in the area | region on the A1 direction side and B1 direction side of the 2nd main surface 11b of the insulating substrate 11, and the area | region on the A2 direction side and B2 direction side, respectively. The A1 and A2 directions in FIGS. 7, 8, 11, 12, and 13 coincide with the −Z ′ direction and the + Z ′ direction in FIGS. 9 and 10, respectively. FIG. 7, FIG. 8, FIG. 12, B1 and B2 directions in FIG. 13 coincide with the −X direction and the + X direction in FIGS. 9 and 10, respectively.

  The crystal unit 100 has a package size of, for example, 1.0 × 0.8 mm, and is intended to be reduced in size and height. In addition, with the miniaturization, the package 112 does not form a castellation and uses a through hole (through hole) described later to conduct the electrode.

  Here, each member of the crystal vibrating plate 102, the first sealing member 103, and the second sealing member 104 constituting the crystal resonator 100 will be described with reference to FIGS.

  As shown in FIGS. 9 and 10, the crystal diaphragm 102 is a piezoelectric substrate made of crystal, and both main surfaces (first main surface 211 and second main surface 212) are flat and smooth surfaces (mirror finishing). It is formed as. In this embodiment, an AT-cut quartz plate that performs thickness shear vibration is used as the quartz plate 102. In the crystal diaphragm 102 shown in FIGS. 9 and 10, both main surfaces 211 and 212 of the crystal diaphragm 102 are XZ ′ planes. In this XZ ′ plane, the direction parallel to the short side direction (short side direction) of the crystal diaphragm 102 is the X axis direction, and the direction parallel to the long direction (long side direction) of the crystal diaphragm 102 is the Z ′ axis. It is considered to be a direction. The AT cut is an angle of 35 ° around the X axis with respect to the Z axis among the electric axis (X axis), the mechanical axis (Y axis), and the optical axis (Z axis), which are the three crystal axes of artificial quartz. This is a processing method of cutting at an angle inclined by 15 '. In an AT cut quartz plate, the X axis coincides with the crystal axis of the quartz crystal. The Y′-axis and the Z′-axis coincide with the axes inclined by 35 ° 15 ′ from the Y-axis and the Z-axis of the crystal axis of the quartz crystal, respectively. The Y′-axis direction and the Z′-axis direction correspond to the cutting direction when cutting the AT-cut quartz plate.

  A pair of excitation electrodes (a first excitation electrode 221 and a second excitation electrode 222) are formed on both main surfaces 211 and 212 of the quartz crystal vibrating plate 102. The crystal vibrating plate 102 holds the vibrating portion 122 by connecting the vibrating portion 122 formed in a substantially rectangular shape, the outer frame portion 123 surrounding the outer periphery of the vibrating portion 122, and the vibrating portion 122 and the outer frame portion 123. Holding part 124. That is, the crystal diaphragm 102 has a configuration in which the vibrating portion 122, the outer frame portion 123, and the holding portion 124 are integrally provided.

  The holding part 124 is provided only at one place between the vibrating part 122 and the outer frame part 123. Further, the vibration part 122 and the holding part 124 are basically formed thinner than the outer frame part 123. Due to the difference in thickness between the outer frame portion 123 and the holding portion 124, the natural frequency of the piezoelectric vibration of the outer frame portion 123 and the holding portion 124 is different. Is less likely to resonate. In addition, the formation part of the holding | maintenance part 124 is not limited to one place, The holding | maintenance part 124 is two places between the vibration part 122 and the outer frame part 123 (for example, both sides of -Z 'axial direction). May be provided.

  The holding part 124 extends (projects) from only one corner located in the + X direction and the −Z ′ direction of the vibrating part 122 to the outer frame part 123 in the −Z ′ direction. As described above, since the holding portion 124 is provided at the corner portion where the displacement of the piezoelectric vibration is relatively small in the outer peripheral end portion of the vibrating portion 122, the holding portion 124 is a portion other than the corner portion (the central portion of the side). Compared with the case where it is provided, the leakage of piezoelectric vibration to the outer frame portion 123 through the holding portion 124 can be suppressed, and the vibration portion 122 can be more efficiently piezoelectrically vibrated. Further, compared to the case where two or more holding portions 124 are provided, the stress acting on the vibration portion 122 can be reduced, and the frequency shift of the piezoelectric vibration caused by such stress can be reduced to stabilize the piezoelectric vibration. Can be improved.

  The first excitation electrode 221 is provided on the first main surface 211 side of the vibration unit 122, and the second excitation electrode 222 is provided on the second main surface 212 side of the vibration unit 122. The first excitation electrode 221 and the second excitation electrode 222 are connected to lead wires (first lead wire 223 and second lead wire 224) for connecting these excitation electrodes to external electrode terminals. The first lead wiring 223 is drawn from the first excitation electrode 221, and is connected to the connection bonding pattern 127 formed on the outer frame portion 123 via the holding portion 124. The second lead wiring 224 is drawn from the second excitation electrode 222 and is connected to the connection bonding pattern 128 formed on the outer frame portion 123 via the holding portion 124. As described above, the first lead wiring 223 is formed on the first main surface 211 side of the holding portion 124, and the second lead wiring 224 is formed on the second main surface 212 side of the holding portion 124.

  On both main surfaces (first main surface 211 and second main surface 212) of the crystal diaphragm 102, a vibration side seal for joining the crystal diaphragm 102 to the first sealing member 103 and the second sealing member 104 is provided. Each stop is provided. As the vibration side sealing portion of the first main surface 211, a vibration side first bonding pattern 251 for bonding to the first sealing member 103 is formed. In addition, as the vibration side sealing portion of the second main surface 212, a vibration side second bonding pattern 252 for bonding to the second sealing member 104 is formed. The vibration side first joining pattern 251 and the vibration side second joining pattern 252 are provided on the outer frame portion 123 and are formed in an annular shape in plan view. The first excitation electrode 221 and the second excitation electrode 222 are not electrically connected to the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252.

  Further, as shown in FIGS. 9 and 10, the crystal diaphragm 102 has five through holes (through holes) penetrating between the first main surface 211 and the second main surface 212. Specifically, the four first through holes 261 are provided in regions of four corners (corner portions) of the outer frame portion 123, respectively. The second through hole 262 is the outer frame portion 123 and is provided on one side of the vibrating portion 122 in the Z′-axis direction (the −Z ′ direction side in FIGS. 9 and 10). A connection bonding pattern 253 is formed around each of the first through holes 261. Further, around the second through hole 262, a connection bonding pattern 254 is formed on the first main surface 211 side, and a connection bonding pattern 128 is formed on the second main surface 212 side. A first through hole 261 is formed outside the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252, and a second through hole 262 is formed inside the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252. Is formed.

  In the first through hole 261 and the second through hole 262, through electrodes for conducting the electrodes formed on the first main surface 211 and the second main surface 212 are provided along the inner wall surfaces of the respective through holes. Is formed. In addition, the central portion of each of the first through hole 261 and the second through hole 262 is a hollow through portion that penetrates between the first main surface 211 and the second main surface 212. Note that the through electrode is not limited to having a through part, and may be formed in a solid state without a through part.

  In the crystal diaphragm 102, the first excitation electrode 221, the second excitation electrode 222, the first extraction wiring 223, the second extraction wiring 224, the first bonding pattern 251, the vibration side second bonding pattern 252, and the connection bonding pattern 253. , 254, 27, and 28 can be formed by the same process. Specifically, these are formed by laminating a base film formed by physical vapor deposition on both main surfaces 211 and 212 of the crystal diaphragm 102 and by physical vapor deposition on the base film. And a bonding film. In this embodiment, Ti (or Cr) is used for the base film, and Au is used for the bonding film.

  As shown in FIGS. 7 and 8, the first sealing member 103 is a substantially rectangular parallelepiped substrate formed of crystal, and the second main surface 312 (the crystal diaphragm 102 is attached to the first sealing member 103). The surface to be joined) is formed as a flat smooth surface (mirror finish). In the present embodiment, an AT-cut quartz plate similar to the quartz diaphragm 102 described above is used as the first sealing member 103.

  Connection joint patterns 137 and 138 are formed in the four corner regions of the first main surface 311 of the first sealing member 103 (the outer main surface that does not face the crystal diaphragm 102). The joint pattern 137 for connection is provided in two places located on the diagonal among the four corner regions of the first main surface 311 of the first sealing member 103, and is located on the diagonal among the four corner regions. Connection patterns 138 for connection are provided in the remaining two places. The connection bonding pattern 137 is provided in each of the first principal surface 311 of the first sealing member 103 on the A1 direction side and B1 direction side regions, and on the A2 direction side and B2 direction side regions. The connection bonding pattern 138 is provided in a region on the A2 direction side and the B1 direction side of the first main surface 311 of the first sealing member 103 and a region on the A1 direction side and the B2 direction side, respectively.

  As shown in FIGS. 7 and 8, the first sealing member 103 has six through holes (through holes) penetrating between the first main surface 311 and the second main surface 312. Specifically, four third through holes 322 are provided in the four corner regions of the first sealing member 103. The fourth and fifth through holes 323 and 324 are respectively provided in the A2 direction and the A1 direction in FIGS. In the third through-hole 322 and the fourth and fifth through-holes 323 and 324, through-electrodes for conducting the electrodes formed on the first main surface 311 and the second main surface 312 are provided in the respective through holes. It is formed along the inner wall surface. In addition, the central portion of each of the third through hole 322 and the fourth and fifth through holes 323 and 324 is a hollow through portion that penetrates between the first main surface 311 and the second main surface 312. Note that the through electrode is not limited to having a through part, and may be formed in a solid state without a through part.

  The through electrode of the fourth through hole 323 is connected to the through electrode of the third through hole 322 provided at the end in the A2 direction and the end in the B2 direction via the connection bonding pattern 137. The through electrode of the fifth through hole 324 is connected to the through electrode of the third through hole 322 provided at the end in the A1 direction and the end in the B1 direction via the connection bonding pattern 137. In addition, a connection bonding pattern 138 is provided around the third through hole 322 provided at the end in the A2 direction and the end in the B1 direction, and is provided at the end in the A1 direction and the end in the B2 direction. A connection bonding pattern 138 is provided around the third through hole 322 provided.

  On the second main surface 312 of the first sealing member 103, a sealing-side first bonding pattern 321 is formed as a sealing-side first sealing portion for bonding to the crystal vibrating plate 102. The sealing side first bonding pattern 321 is formed in an annular shape in plan view. A third through hole 322 is formed outside the sealing side first bonding pattern 321, and fourth and fifth through holes 323 and 324 are formed inside the sealing side first bonding pattern 321.

  In addition, on the second main surface 312 of the first sealing member 103, connection bonding patterns 134 are formed around the third through holes 322, respectively. A connection bonding pattern 351 is formed around the fourth through hole 323, and a connection bonding pattern 352 is formed around the fifth through hole 324. Further, a connection bonding pattern 353 is formed on the opposite side (A2 direction side) of the first sealing member 103 with respect to the connection bonding pattern 351, and the connection bonding pattern 351 and the connection bonding pattern 351 are connected. The pattern 353 is connected by a wiring pattern 133. Note that the connection bonding pattern 353 is not connected to the connection bonding pattern 352.

  In the first sealing member 103, the sealing-side first bonding pattern 321, the connecting bonding patterns 34, 351 to 353, and the wiring pattern 133 can be formed by the same process. Specifically, these are a base film formed by physical vapor deposition on the second main surface 312 of the first sealing member 103 and a physical vapor deposition on the base film to form a stacked layer. And the formed bonding film. In this embodiment, Ti (or Cr) is used for the base film, and Au is used for the bonding film.

  As shown in FIGS. 11 and 12, the second sealing member 104 is a substantially rectangular parallelepiped substrate formed of quartz, and the first main surface 411 (on the crystal diaphragm 102) of the second sealing member 104. The surface to be joined) is formed as a flat smooth surface (mirror finish). In the present embodiment, an AT-cut quartz plate similar to the quartz diaphragm 102 described above is used as the second sealing member 104.

  On the first main surface 411 of the second sealing member 104, a sealing side second bonding pattern 421 is formed as a sealing side second sealing portion for bonding to the quartz crystal plate 102. The sealing-side second bonding pattern 421 is formed in an annular shape in plan view.

  Four external electrode terminals 143a to 143d that are electrically connected to the outside are provided on the second main surface 412 of the second sealing member 104 (the outer main surface that does not face the crystal diaphragm 102). The external electrode terminals 143a to 143d are located in the four corner regions of the second sealing member 104, respectively.

  As shown in FIGS. 11 and 12, the second sealing member 104 has four through holes (through holes) penetrating between the first main surface 411 and the second main surface 412. Specifically, the four sixth through holes 144 are provided in the four corner regions of the second sealing member 104. The sixth through hole 144 is formed outside the sealing-side second bonding pattern 421.

  In the sixth through-hole 144, through-electrodes for conducting the electrodes formed on the first main surface 411 and the second main surface 412 are formed along the inner wall surfaces of the through-holes. Further, the central portion of each of the sixth through holes 144 is a hollow through portion that penetrates between the first main surface 411 and the second main surface 412. Further, on the first main surface 411 of the second sealing member 104, connection bonding patterns 145 are formed around the sixth through holes 144, respectively. Note that the through electrode is not limited to having a through part, and may be formed in a solid state without a through part.

  In the second sealing member 104, the sealing-side second bonding pattern 421 and the connecting bonding pattern 145 can be formed by the same process. Specifically, these are formed by stacking a base film formed by physical vapor deposition on the first main surface 411 of the second sealing member 104 and by physical vapor deposition on the base film. And the formed bonding film. In this embodiment, Ti (or Cr) is used for the base film, and Au is used for the bonding film.

  In the quartz crystal resonator 100 including the quartz crystal vibrating plate 102, the first sealing member 103, and the second sealing member 104, the quartz crystal vibrating plate 102 and the first sealing member 103 are connected to the vibration side first bonding pattern 251 and Diffusion bonding (Au—Au bonding) is performed in a state where the sealing-side first bonding pattern 321 is overlaid, and the quartz crystal vibrating plate 102 and the second sealing member 104 are connected to the vibration-side second bonding pattern 252 and the sealing-side second. The package 112 having the sandwich structure shown in FIG. 6 is manufactured by diffusion bonding (Au—Au bonding) in a state where the bonding patterns 421 are overlapped. Accordingly, the annular sealing portion formed by diffusion bonding of the vibration side first bonding pattern 251 and the sealing side first bonding pattern 321, and the vibration side second bonding pattern 252 and the sealing side second bonding pattern 421. The inner space of the package 112, that is, the accommodation space of the vibrating portion 122 is hermetically sealed by the annular sealing portion formed by diffusion bonding. In FIG. 6, a sealing portion formed by diffusion bonding of the vibration side first bonding pattern 251 and the sealing side first bonding pattern 321, and the vibration side second bonding pattern 252 and the sealing side second bonding pattern. Illustration of the sealing part formed by diffusion bonding of 421 is omitted.

  At this time, diffusion bonding (Au—Au bonding) is performed in a state where the above-described bonding patterns for connection are also overlapped. In the present embodiment, the temperature sensor 10 is also mounted on the package 112 of the crystal unit 100 by diffusion bonding (Au—Au bonding) in a state where the connection bonding patterns are overlapped. Specifically, the connection bonding pattern 16 on the second main surface 11b of the insulating substrate 11 of the temperature sensor 10 and the connection bonding pattern 138 on the first main surface 311 of the first sealing member 103 are bonded, Further, the connection bonding pattern 17 on the second main surface 11 b of the insulating substrate 11 of the temperature sensor 10 and the connection bonding pattern 137 on the first main surface 311 of the first sealing member 103 are bonded. The temperature sensor 10 may be mounted on the package 112 of the crystal unit 100 simultaneously with the formation of the package 112 (lamination of the crystal diaphragm 102, the first sealing member 103, and the second sealing member 104). It may be performed after the package 112 is formed.

  Then, the electrical connection between the first excitation electrode 221 and the second excitation electrode 222 and the external electrode terminals 143c and 143d can be obtained by joining the joint patterns for connection. In addition, electrical conduction between the electrode layers 12 and 12 of the temperature sensor 10 and the external electrode terminals 143a and 143b can be obtained.

  Specifically, the first excitation electrode 221 includes the first lead-out wiring 223, the connection portion between the connection bonding pattern 127 and the connection bonding pattern 353, the wiring pattern 133, the connection bonding pattern 351, and the fourth through hole 323. Through-electrodes, the junction between the connection junction pattern 137 and the connection junction pattern 17, the through-electrode in the third through-hole 322, the junction between the connection junction pattern 134 and the connection junction pattern 253, the first penetration The electrode is connected to the external electrode terminal 143d through the through electrode in the hole 261, the bonding portion between the connection bonding pattern 253 and the connection bonding pattern 145, and the through electrode in the sixth through hole 144 in order.

  The second excitation electrode 222 includes a second lead wire 224, a connection bonding pattern 128, a through electrode in the second through hole 262, a connection portion between the connection bonding pattern 254 and the connection bonding pattern 352, and a fifth through hole. The through electrode in 324, the junction between the connection junction pattern 137 and the connection junction pattern 17, the through electrode in the third through hole 322, the junction between the connection junction pattern 134 and the connection junction pattern 253, the first The through electrode is connected to the external electrode terminal 143c through the through electrode in the through hole 261, the bonding portion between the connecting bonding pattern 253 and the connecting bonding pattern 145, and the through electrode in the sixth through hole 144 in order.

  In addition, the electrode layers 12 and 12 of the temperature sensor 10 include a through electrode in the through hole 11c, a joint portion between the connection joint pattern 16 and the connection joint pattern 138, a through electrode in the third through hole 322, and a connection purpose. A joint portion between the joint pattern 134 and the connection joint pattern 253, a through electrode in the first through hole 261, a joint portion between the connection joint pattern 253 and the connection joint pattern 145, and a through electrode in the sixth through hole 144 Are sequentially connected to the external electrode terminals 143a and 143b.

  Here, of the four external electrode terminals 143 a to 143 d formed on the second main surface 412 of the second sealing member 104, the two external electrode terminals 143 a and 143 b are electrically connected to the electrode layer 12 of the temperature sensor 10. It is formed as an external terminal for a temperature sensor connected to. In this example, the external electrode terminal 143a at the end in the A2 direction and the end in the B1 direction and the external electrode terminal 143b at the end in the A1 direction and the end in the B2 direction shown in FIG. It has become.

  On the other hand, the remaining two external electrode terminals 143c and 143d are formed as excitation electrode external terminals electrically connected to the first excitation electrode 221 and the second excitation electrode 222. In this example, the external electrode terminal 143c at the end in the A1 direction and the end in the B1 direction and the external electrode terminal 143d at the end in the A2 direction and the end in the B2 direction shown in FIG. It has become.

  The temperature sensor electrical path between the temperature sensor external terminal and the electrode layer 12 of the temperature sensor 10, and the excitation electrode between the excitation electrode external terminal and the first excitation electrode 221 and the second excitation electrode 222. Electrical paths are independent of each other. An electrical path for the temperature sensor includes a through-hole 144 formed in the second sealing member 104 (in this case, the through-hole 144 at the end in the A2 direction and the end in the B1 direction shown in FIGS. 11 and 12, and A1 Through-hole 144 at the end in the direction B2 and the end in the B2 direction, and a through-hole 261 formed in the crystal diaphragm 102 (in this case, the end in the −X direction and the end in the + Z ′ direction shown in FIGS. Through-holes 261, end portions in the + X direction and end portions in the −Z ′ direction, and through-holes 322 formed in the first sealing member 103 (in this case, FIGS. 7 and 8) The end portion in the A2 direction and the end portion in the B1 direction and the through hole 322 in the end portion in the A1 direction and the end portion in the B2 direction) shown in FIG.

  On the other hand, the electrical path for the excitation electrode includes a through hole 144 formed in the second sealing member 104 (in this case, the through hole 144 at the end in the A1 direction and the end in the B1 direction shown in FIGS. 11 and 12). , Through-holes 144 at the end in the A2 direction and at the end in the B2 direction), and through-holes 261 formed in the crystal diaphragm 102 (in this case, the end in the + X direction and the + Z ′ direction shown in FIGS. 9 and 10) The through hole 261 at the end, the through hole 261 at the end in the −X direction and the end in the −Z ′ direction, and the through hole 322 formed in the first sealing member 103 (in this case, FIG. The structure includes a through hole 322 at an end portion in the A1 direction and an end portion in the B1 direction and a through hole 322 at an end portion in the A2 direction and an end portion in the B2 direction shown in FIG.

  In the quartz resonator 100 manufactured by diffusion bonding, the first sealing member 103 and the quartz vibrating plate 102 have a gap of 1.00 μm or less, and the second sealing member 104 and the quartz vibrating plate 102 are Has a gap of 1.00 μm or less. That is, the thickness of the bonding material between the first sealing member 103 and the crystal vibrating plate 102 is 1.00 μm or less, and the thickness of the bonding material between the second sealing member 104 and the crystal vibrating plate 102 is 1.00 μm or less (specifically, 0.15 μm to 1.00 μm in the Au—Au bonding of this embodiment). For comparison, a conventional metal paste sealing material using Sn has a thickness of 5 μm to 20 μm.

  Thereby, the height of the crystal unit 100 can be made difficult to vary. For example, unlike this embodiment, a Sn bonding material in which the gap between the sealing members (the first sealing member 103 and the second sealing member 104 in this embodiment) and the quartz crystal vibration plate 102 is larger than 1 μm is used. When the metal paste sealing material is used, the metal paste sealing material is patterned (vibration side first bonding pattern 251, vibration side second bonding pattern 252, sealing side first bonding pattern 321, sealing side second bonding pattern. 421) There is a variation in the height when formed on top. Further, even after bonding, due to the heat capacity distribution of the formed patterns (vibration side first bonding pattern 251, vibration side second bonding pattern 252, sealing side first bonding pattern 321, sealing side second bonding pattern 421). A uniform gap (a gap between the first sealing member 103 and the crystal diaphragm 102 in the present embodiment or a gap between the second sealing member 104 and the crystal diaphragm 102 in the present embodiment) does not occur.

  Therefore, in the conventional technique, in the case of a structure in which the three members of the first sealing member, the second sealing member, and the crystal diaphragm are laminated, a difference occurs in each gap between these three members. As a result, the three laminated members are joined in a state where the parallelism cannot be maintained. In particular, this problem becomes conspicuous as the package 112 is reduced in height. Therefore, in this embodiment, since the upper limit of the gap is set to 1.00 μm, the three members of the first sealing member 103, the second sealing member 104, and the crystal diaphragm 102 are kept in parallel. In this embodiment, the height of the package 112 can be reduced. That is, in this embodiment, even if the package 112 is reduced in height, it is possible to provide the crystal unit 100 that is thin and has superior dimensional accuracy. Furthermore, the variation in the inter-stack capacitance of the crystal unit 100 can be suppressed, and the frequency variation caused by this can also be suppressed.

  According to the present embodiment, in the configuration in which the temperature sensor 10 is arranged outside the internal space 113 that hermetically seals the vibration part 122 by the first sealing member 103 and the second sealing member 104, the temperature sensor 10 is Since it is configured as a thin film thermistor having the electrode layer 12 and the resistance layer 14, it is possible to reduce the height of the crystal resonator 100 with the temperature sensor. In this case, when forming the electrode layer 12 and the resistance layer 14 on the first sealing member 103 and the like by forming the electrode layer 12 and the resistance layer 14 on the substantially entire surface of the first main surface 11 a of the insulating substrate 11. In comparison, it is possible to secure a wider area for forming the electrode layer 12 and the resistance layer 14.

  In addition, since the insulating substrate 11 is interposed between the first sealing member 103 and the electrode layer 12 of the temperature sensor 10, electrical conduction through the insulating substrate 11 affects the characteristics of the temperature sensor 10. Can be suppressed. That is, the insulating substrate 11 can be suitably used as a base material on which the electrode layer 12 and the like of the temperature sensor 10 are formed. In addition, by using the insulating substrate 11 as a quartz plate, the first sealing member 103, the quartz vibrating plate 102, the second sealing member 104, and the insulating substrate 11 are made of the same material, so that the temperature change can be prevented. Distortion can be reduced. Thereby, the distortion of the entire crystal unit 100 due to the temperature change can be relaxed.

  In the above embodiment, the insulating substrate 11 of the temperature sensor 10 is mounted on the first sealing member 103, but the first sealing member 103 and the second sealing member 104 are used as the insulating substrate of the temperature sensor 10. May be. For example, the electrode layer 12, the interface layer 13, and the resistance layer 14 may be stacked on the first main surface 311 of the first sealing member 103.

  In the above embodiment, the insulating substrate 11 of the temperature sensor 10 is bonded to the first sealing member 103 by diffusion bonding. However, the insulating substrate 11 of the temperature sensor 10 is bonded to the first sealing member 103 using a brazing material. May be.

  In the above embodiment, the crystal unit 100 has a structure in which the first sealing member 103, the crystal plate 102, and the second sealing member 104 are laminated. However, the present invention is applicable. For example, the present invention can be applied to a crystal resonator having a structure in which a quartz diaphragm is accommodated in a recess of a base member and the recess of the base member is hermetically sealed by a lid member. In this case, the temperature sensor 10 may be provided on the bottom surface of the recess of the base member, and the electrode layer 12, the interface layer 13, and the resistance layer 14 may be stacked on the bottom surface of the recess of the base member.

  Alternatively, for example, the present invention can also be applied to a crystal resonator having a structure in which a quartz diaphragm is accommodated in a first recess of an H-shaped base member and the first recess of the base member is hermetically sealed by a lid member. . In this case, the temperature sensor 10 may be provided on the bottom surface of the second recess of the base member, and the electrode layer 12, the interface layer 13, and the resistance layer 14 may be stacked on the bottom surface of the second recess of the base member. .

  In the above embodiment, the case where the present invention is applied to the crystal resonator 100 has been described. However, the present invention can also be applied to piezoelectric vibration devices other than the crystal resonator 100 (for example, a crystal oscillator). Further, although the AT cut crystal is used as the crystal diaphragm 102, the present invention is not limited to this, and a crystal other than the AT cut crystal may be used. Moreover, although AT cut quartz was used as the first sealing member 103 and the second sealing member 104, the present invention is not limited to this, and quartz other than AT cut quartz or brittle materials other than quartz (for example, glass or the like) ) May be used.

  Embodiment disclosed this time is an illustration in all the points, Comprising: It does not become the basis of limited interpretation. The technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, the technical scope of the present invention includes all modifications within the scope and meaning equivalent to the scope of the claims.

  The present invention can be used for a temperature sensor and a piezoelectric vibration device including the temperature sensor.

DESCRIPTION OF SYMBOLS 10 Temperature sensor 11 Insulating substrate 12 Electrode layer 13 Interface layer 14 Resistance layer 100 Crystal oscillator (piezoelectric vibration device)

Claims (6)

A temperature sensor comprising a resistance layer formed of a thermistor material on an insulating substrate, and a pair of electrode layers formed opposite to each other with the resistance layer in plan view,
An interface layer is interposed between the resistance layer and the electrode layer. The temperature sensor according to claim 1,
The electrode layer is an Au layer;
The temperature sensor, wherein the interface layer is a Ti layer or a Cr layer. The temperature sensor according to claim 1 or 2,
The temperature sensor, wherein the thermistor material is a chromium compound containing oxygen and nitrogen as components. The temperature sensor according to any one of claims 1 to 3,
The temperature sensor, wherein the electrode layer is formed in a comb shape. The temperature sensor according to any one of claims 1 to 4,
The temperature sensor, wherein the electrode layer, the interface layer, and the resistance layer are laminated in this order on the surface of the insulating substrate.   A piezoelectric vibration device comprising the temperature sensor according to claim 1.

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