JP2015180871A - Wireless temperature sensor and manufacturing method of same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless temperature sensor exhibiting excellent characteristics in terms of both responsiveness of temperature measurements and transmission/reception efficiency with respect to communication with outside.SOLUTION: A wireless temperature sensor 1 comprises: a container body 20 formed of a first ceramic substrate; a lid 10 formed of a second ceramic substrate lower in firing temperature than the first ceramic substrate; an antenna; and a temperature detection element 30, the first ceramic substrate including an antenna electrode 11 and a GND electrode 13 higher in heat conductivity than the second ceramic substrate and formed integrally on the lid 10, and the temperature detection element 30 being electrically connected to the antenna electrode 11 and the GND electrode 13 and fixed into the container body 20 and the lid 10 by bonding the container body 20 and the lid 10 together.

Description

  The present invention relates to a wireless temperature sensor and a manufacturing method thereof.

  There are several methods for measuring temperature using a wired cable. Examples include temperature-resistance characteristics and thermoelectromotive force using a thermistor or thermocouple, radiation thermometers that measure temperature from infrared rays emitted from objects, and physical characteristics of piezoelectric elements and surface acoustic wave elements depending on temperature. There is a method using a changing principle.

  However, for example, when measuring the temperature of a wafer in a chamber in a semiconductor process, the arrangement of a wired cable connected for output to the outside from a measurement unit arranged in the chamber is limited by the chamber and associated devices. I will receive it.

  As a solution to this problem, a wireless temperature sensor is known in which a unit provided with a transmission / reception antenna in a surface acoustic wave element operates in response to a signal transmitted from an external antenna and returns a response signal including measurement information. . (For example, see Patent Document 1)

  The outline of the wireless temperature measurement sensor described in Patent Document 1 will be described with reference to FIG. FIG. 25 is a diagram for explaining the structure of the wireless temperature measurement sensor 101 disclosed in Patent Document 1. In FIG. The wireless temperature measurement sensor 101 includes an antenna mechanism 102 for transmitting and receiving radio waves, an excitation electrode 103 connected to the antenna mechanism 102, a surface acoustic wave element 104 connected to the excitation electrode 103, and the like. The antenna mechanism 102 includes a sensor body 105, a planar electrode 107 formed on one surface of the sensor body 105, and a ground electrode 108 formed on a surface opposite to the surface on which the planar electrode 107 of the sensor body 105 is formed. Etc.

JP 2004-347451 A

  In the configuration disclosed in Patent Document 1, the thermal response of temperature measurement is determined by the thermal conductivity of the substance of the sensor body, and the capacitive component of the antenna mechanism is determined by the dielectric constant of the substance of the sensor body.

  However, since there is no correlation between the dielectric constant and the thermal conductivity of the substance, even if a substance with a high dielectric constant is used for the sensor body, the thermal conductivity of the sensor body, which is important for temperature measurement, is low. Similarly, even if a substance having high thermal conductivity is adopted for the sensor body, the dielectric constant of the sensor body may be lowered. Therefore, it has been difficult to realize a wireless temperature sensor having excellent characteristics in both temperature response and external transmission / reception efficiency.

  An object of the present invention is to solve the above-described problems, and to provide a wireless temperature sensor having excellent characteristics in both temperature response and external transmission / reception efficiency.

  A method for manufacturing a wireless temperature sensor according to the present invention comprises preparing a first ceramic green sheet and a second ceramic green sheet, wherein the first ceramic green has a higher thermal conductivity than the second ceramic green sheet. The step of firing the sheet to form the container body, the antenna electrode and the GND electrode are arranged on the second ceramic green sheet, and the second ceramic green sheet on which the antenna electrode and the GND electrode are arranged is used as the first ceramic green sheet. A step of forming a lid having an antenna by firing at a firing temperature lower than that of the green sheet; a step of electrically connecting the temperature detection element to the antenna electrode and the GND electrode; and the temperature detection element inside the container body and the lid And a step of bonding the container main body and the lid so as to be fixed to each other.

  With the above configuration, the container body with high thermal conductivity and the lid with excellent transmission / reception function (high frequency characteristics) are formed of different ceramic materials, respectively, and wireless temperature excellent in both temperature measurement responsiveness and transmission / reception efficiency A sensor can be manufactured.

  In the manufacturing method of the wireless temperature sensor, the container body and the lid may be bonded together so that the temperature detection element contacts the inside of the container body.

  With the above configuration, it is possible to manufacture a wireless temperature sensor with further improved temperature measurement responsiveness.

  In the manufacturing method of the wireless temperature sensor, the container body may have an opening on the side opposite to the side bonded to the lid.

  With the above configuration, it is possible to manufacture a wireless temperature sensor with further improved temperature measurement responsiveness.

  In the method for manufacturing a wireless temperature sensor, the step of bonding the container body and the lid may be performed by bonding the container body and the lid so that a heat conductor is disposed between the container body and the temperature detection element. .

  With the above configuration, it is possible to manufacture a wireless temperature sensor with further improved temperature measurement responsiveness.

  In the manufacturing method of the wireless temperature sensor, the container body may have a porous structure or a mesh structure.

  With the above configuration, it is possible to measure the environmental temperature (atmosphere temperature) more accurately.

  In the method for manufacturing a wireless temperature sensor, in the step of forming the lid, a conductor pattern serving as an antenna electrode is disposed on one surface of the second ceramic green sheet, and a GND electrode is formed on the inner layer of the second ceramic green sheet. A conductor pattern is disposed, and a first via hole that is electrically connected to the antenna electrode and a second via hole that is electrically connected to the GND electrode are formed on the second ceramic green sheet, and on the other surface of the second ceramic green sheet, A first electrode pad that is electrically connected to the first via hole and a second electrode pad that is electrically connected to the second via hole may be formed.

  With the above configuration, an antenna can be formed using one type of ceramic green sheet.

  In the manufacturing method of the wireless temperature sensor, the step of forming the lid is electrically connected to the second electrode pad on the other surface of the second ceramic green sheet and thermally connected to the temperature detection element and the container body. A heat conductive layer may be formed.

  With the above configuration, it is possible to form a heat conductive layer that further increases the heat conductivity from the container body to the lid, and it is possible to manufacture a wireless temperature sensor with further improved temperature measurement responsiveness.

  The manufacturing method of the wireless temperature sensor may further include a step of fixing the temperature detection element on the second via hole on the heat conductive layer.

  With the above configuration, it is possible to reduce the amount of heat transferred to the inside of the lid by the via hole, so that a wireless temperature sensor with improved temperature measurement responsiveness and reduced variation in antenna characteristics due to the influence of heat is provided. Can be manufactured.

  The method for manufacturing a wireless temperature sensor may further include a step of forming a protective layer covering the antenna electrode on the second ceramic green sheet.

  With the above configuration, since the metal body is not exposed on the surface of the wireless temperature sensor, the anti-static property is improved and the operation abnormality due to the adhesion of conductive obstacles such as metal fragments can be prevented, and the reliability is high. A wireless temperature sensor can be manufactured.

  A wireless temperature sensor according to the present invention includes a container body formed from a first ceramic substrate, a lid formed from a second ceramic substrate whose firing temperature is lower than that of the first ceramic substrate, an antenna, and a temperature detection The first ceramic substrate has a higher thermal conductivity than the second ceramic substrate, the antenna includes an antenna electrode and a GND electrode integrally formed on the lid, and the temperature detection element is It is electrically connected to the antenna electrode and the GND electrode, and is fixed to the inside of the container main body and the lid by bonding the container main body and the lid.

  With the above configuration, the container body with high thermal conductivity and the lid with excellent transmission / reception function (high frequency characteristics) are formed of different ceramic materials, respectively, and the wireless temperature with excellent temperature response and transmission / reception efficiency A sensor can be manufactured.

  In the wireless temperature sensor, the temperature detection element may be fixed inside the container body and the lid so as to contact the inside of the container body.

  With the above configuration, it is possible to provide a wireless temperature sensor with further improved temperature measurement responsiveness.

  In the wireless temperature sensor, the container body may have an opening on the side opposite to the side bonded to the lid.

  With the above configuration, it is possible to provide a wireless temperature sensor with further improved temperature measurement responsiveness.

  The wireless temperature sensor may further include a heat conductor disposed between the container body and the temperature detection element.

  With the above configuration, it is possible to provide a wireless temperature sensor with further improved temperature measurement responsiveness.

  In the wireless temperature sensor, the container body may have a porous structure or a mesh structure.

  With the above configuration, it is possible to measure the environmental temperature (atmosphere temperature) more accurately.

  In the wireless temperature sensor, the first ceramic substrate may be HTCC (High Temperature Coated Ceramics), and the second ceramic substrate may be LTCC (Low Temperature Coated Ceramics).

With the above configuration, the container body is made of a high-temperature fired ceramic material such as alumina-based ceramic, and the lid is a high-frequency characteristic obtained by adding boron (B), silicon (Si) or the like to aluminum oxide (Al ₂ O ₃ ) It can be composed of good low temperature fired ceramics. Therefore, a wireless temperature sensor utilizing each characteristic can be realized.
In particular, since the firing temperature of LTCC used for the lid is low, it is possible to use silver (Ag) or copper (Cu) having high electrical conductivity as a conductor of the antenna mechanism. Is very advantageous.

  In the wireless temperature sensor, the antenna electrode material of the antenna may be silver (Ag) or copper (Cu).

  With the above configuration, Ag or Cu has a low conductor resistivity (high electrical conductivity). Therefore, by selecting an LTCC having a low dielectric loss tangent, the transmission / reception efficiency (high-frequency characteristics) of the wireless temperature sensor is further improved.

  In the wireless temperature sensor, the container body and the lid may be thermally connected, and the temperature detection element and the lid may be thermally connected.

  With the above configuration, the heat of the measurement object is conducted to the temperature detection element via the container body and the lid, so that the temperature measurement responsiveness of the wireless temperature sensor is further improved.

  In the wireless temperature sensor, the antenna electrode may be formed on the surface of the second ceramic substrate, and the GND electrode may be formed on the inner layer of the second ceramic substrate.

  With the above configuration, the microstrip antenna is configured and is small and thin despite the high gain, and the entire wireless temperature sensor can be reduced in size and thickness.

  The wireless temperature sensor further includes a first wiring electrode and a second wiring electrode formed on the back surface of the second ceramic substrate, and the first wiring electrode is electrically connected to the temperature detection element and the antenna electrode, respectively. The second wiring electrode may be electrically connected to the temperature detection element and the GND electrode, respectively.

  With the above configuration, noise resistance and high voltage resistance are improved, and the reliability of the wireless temperature sensor is increased.

  In the wireless temperature sensor, the second wiring electrode may be thermally connected to the temperature detection element and the container body.

  With the above configuration, it is possible to provide a wireless temperature sensor with further improved temperature measurement responsiveness.

  The wireless temperature further includes a via hole formed in the second ceramic substrate and electrically connected to the GND electrode and the second wiring electrode, and the temperature detection element may be fixed on the via hole on the second wiring electrode. Good.

  With the above configuration, it is possible to reduce the amount of heat transferred to the inside of the lid by the via hole, so that a wireless temperature sensor with improved temperature measurement responsiveness and reduced variation in antenna characteristics due to the influence of heat is provided. It becomes possible to provide.

  The wireless temperature sensor may further include a protective layer that covers the antenna electrode.

  With the above configuration, since the metal body is not exposed on the surface of the wireless temperature sensor, the anti-static property is improved, and an operation abnormality due to adhesion of conductive obstacles such as metal fragments can be prevented. Reliability is improved.

  According to the present invention, a container body having high thermal conductivity and a lid having an excellent transmission / reception function (high frequency characteristics) are formed of different ceramic materials, respectively, and excellent characteristics in both temperature response and transmission / reception efficiency. A wireless temperature sensor can be provided.

2 is a diagram for explaining the structure of a wireless temperature sensor 1; FIG. (A) is a top view of the temperature detection element 30, (b) is sectional drawing along CC line shown to Fig.2 (a) of the temperature detection element 30, (c) is the temperature detection element 30. FIG. It is sectional drawing along the DD line | wire shown to Fig.2 (a). FIG. 2 is a plan view of the wireless temperature sensor 1, and (b) is a side view of the wireless temperature sensor 1. FIG. It is sectional drawing along the BB line shown in FIG.3 (b) of the wireless temperature sensor 1. FIG. It is a figure for demonstrating the temperature detection method by the wireless temperature sensor. It is a graph which shows the time change of reflective surface acoustic wave intensity | strength Rwp in a surface acoustic wave element. It is a figure for demonstrating the structure of the temperature measurement system using the wireless temperature sensor. 4 is a flowchart showing an outline of a manufacturing process of the wireless temperature sensor 1. It is a figure for demonstrating the container main body assembly and high temperature baking process of the wireless temperature sensor 1. FIG. It is a figure for demonstrating the lid assembly of the wireless temperature sensor 1, and a low-temperature baking process. It is a figure for demonstrating mounting and the whole assembly process of the temperature detection element 30 of the wireless temperature sensor 1. FIG. It is a figure for demonstrating the structure of the other wireless temperature sensor. It is a figure for demonstrating the lid assembly of the wireless temperature sensor 2, and a low-temperature baking process. It is a figure for demonstrating the structure of the another wireless temperature sensor 3. FIG. (A) is sectional drawing which represented typically the propagation | transmission path | route of the heat from the measuring object (not shown) of the wireless temperature sensor 2, (b) is propagation of the heat from the measuring object (not shown) of the wireless temperature sensor 3. It is sectional drawing which represented the path | route typically. It is a figure for demonstrating the structure of the another wireless temperature sensor 4. FIG. It is a figure for demonstrating the lid assembly of the wireless temperature sensor 4, and a low-temperature baking process. It is a figure for demonstrating the structure of the another wireless temperature sensor 5. FIG. It is a figure for demonstrating the temperature detection element mounting process of the wireless temperature sensor. It is a figure for demonstrating the structure of the other wireless temperature sensor 6. FIG. It is the figure which looked at the wireless temperature sensor 6 from the direction 6D of FIG. It is a figure for demonstrating the structure of another wireless temperature sensor. It is a figure for demonstrating the temperature detection element mounting of the wireless temperature sensor 7, and the whole assembly process. It is a figure for demonstrating the structure of the another wireless temperature sensor 8. FIG. It is a figure for demonstrating the structure of the wireless temperature measurement module of a prior art example.

  Hereinafter, embodiments of a wireless temperature sensor according to the present invention will be described in detail with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the invention described in the claims and equivalents thereof. Note that the dimensions of each drawing do not reflect the exact dimensions, and the size of parts may be exaggerated for explanation, and some parts may be omitted for explanation. The same numbers are assigned to the same elements, and duplicate descriptions are omitted.

  FIG. 1 is a diagram for explaining the structure of the wireless temperature sensor 1. In addition, the figure shown in FIG. 1 is sectional drawing along the AA line shown to Fig.3 (a) of the wireless temperature sensor 1. FIG.

  As shown in FIG. 1, the wireless temperature sensor 1 includes a container 50 including a container main body 20 and a lid 10, and a temperature detection element 30 fixed inside the container 50. The temperature detection element 30 is mounted on the lid 10.

The container body 20 is a first ceramic substrate and is made of Al ₂ O ₃ which is a high-temperature fired ceramic material generally known as HTCC. A body cavity 20c is formed in the container body 20 by a method described later. The container body 20 is not limited to Al ₂ O _3, and other HTCC having higher thermal conductivity than LTCC described later, such as aluminum nitride (AlN), can also be used.

  The lid 10 is a microstrip antenna formed by laminating an antenna electrode layer 11, an upper layer body 12, a GND electrode layer 13, and an inner layer body 14. A microstrip antenna (hereinafter referred to as an antenna) is also referred to as a planar antenna or a patch antenna, and is an antenna having high gain, a narrow band, and a wide directivity while being capable of being reduced in size and thickness. The upper layer body 12 and the inner layer body 14 together form a second ceramic substrate. The upper layer body 12 and the inner layer body 14 are actually integrally formed without boundaries at the end portions in the drawing by firing described later, but for convenience, the boundary between the upper layer body 12 and the inner layer body 14 is shown in FIG. Is shown.

The upper layer body 12 and the inner layer body 14 which are main elements of the lid 10 each have a thickness of approximately 1 mm, and both are CaO—Al ₂ O ₃ —SiO which is a low-temperature fired ceramic material generally known as LTCC. It is formed of a material obtained by adding Al ₂ O ₃ to _2- B ₂ O ₃ . However, the present invention is not limited to this, and the upper layer body 12 and the inner layer body 14 may be formed using other LTCC. Other _{LTCC, BaO-Al 2 O 3} -SiO 2 -Bi2O 3, BaO-Tio 2 -ZnO, BaO-Nd2O 3 -Bi 2 O 3 -Tio 2, and _{BaO-R 2 O 3 -TiO 2} ( R is an alkali metal). As will be described later, since it is preferable to use Ag or Cu having high electrical conductivity for the conductor pattern formed on the lid 10, the melting point of Cu (about 1083 ° C.) or the melting point of Ag (about 961 ° C.). LTCC having a low firing temperature is preferred. The thickness of each of the upper layer body 12 and the inner layer body 14 is not limited to approximately 1 mm, but varies depending on the ceramic material used, but may be a thickness sufficient to ensure the characteristics as an antenna.

  The antenna electrode layer 11 is an electrode layer made of Cu and having a thickness of about 10 to 15 μm. The antenna electrode layer 11 may have other thicknesses. The antenna electrode layer 11 is a lid bonding pad that is a first electrode pad provided on the lid mounting surface 15 m of the inner layer body 14 through an antenna via hole 11 h that is a first via hole that penetrates the upper layer body 12 and the inner layer body 14. 15a is electrically connected. The antenna via hole 11h and the lid bonding pad 15a are made of Cu.

  The GND electrode layer 13 is an electrode layer made of Cu and having a thickness of about 10 to 15 μm. The GND electrode layer 13 may have another thickness. The GND electrode layer 13 is electrically connected to a lid bonding pad 15b which is a second electrode pad provided on the lid mounting surface 15m of the inner layer body 14 through a GND via hole 13h which is a second via hole penetrating the inner layer body 14. It is connected to the. The GND electrode layer 13 includes a GND pattern opening 13w for penetrating the antenna via hole 11h. The GND pattern opening 13w may be filled with a ceramic material that forms the upper layer body 12 or the inner layer body. The GND via hole 13h and the lid bonding pad 15b are made of Cu.

  The conductor patterns (that is, the antenna electrode layer 11, the antenna via hole 11h, and the lid bonding pad 15a, and the GND electrode layer 13, the GND via hole 13h, and the lid bonding pad 15b) are formed using Cu. Other metals may be used. It is preferable to use Ag or Cu having high electrical conductivity for the conductor pattern.

  The temperature detecting element 30 is mounted on the lid mounting surface 15m of the inner layer body 14 of the lid 10 by a joining method such as a metal brazing method. The element bonding pad 34a of the temperature detection element 30 is connected to the lid bonding pad 15a by a bonding wire 35a. The element bonding pad 34b of the temperature detecting element 30 is connected to the lid bonding pad 15b by a bonding wire 35b. Therefore, the element bonding pad 34 a of the temperature detection element 30 is electrically connected to the antenna electrode layer 11, and the element bonding pad 34 b of the temperature detection element 30 is electrically connected to the GND electrode layer 13.

  2A is a plan view of the temperature detection element 30, and FIG. 2B is a cross-sectional view of the temperature detection element 30 taken along the line CC shown in FIG. 2A. ) Is a cross-sectional view of the temperature detection element 30 taken along line DD shown in FIG.

  In FIG. 2A, the temperature detection element 30 is a surface acoustic wave element, and includes a surface acoustic wave element substrate 31, comb-shaped electrodes 32 a and 32 b provided on the surface of the surface acoustic wave element substrate 31, and a reflector 33. . An element bonding pad 34a is formed at the end of the comb-shaped electrode 32a, and an element bonding pad 34b is formed at the end of the comb-shaped electrode 32b.

The surface acoustic wave element substrate 31 is formed of a single crystal of lithium niobate (LiNbO ₃ ) and has a rectangular plate shape having a plan view size of about 10 mm × 10 mm and a thickness of about 2 mm. The surface acoustic wave element substrate 31 is not limited to this, and a single crystal substrate of a piezoelectric material, a substrate in which a thin film of a piezoelectric material is formed on a glass substrate or a Si substrate, or the like may be used. The piezoelectric material, for example, lithium tantalate (LiTaO _3), quartz (SiO _2), langasite _{(La 3 Ga 5 SiO 14)} , including but such Rangateito _{(La 3 Ta 0.5 Ga 5.5 O} 14), It is not limited to these.

  The comb electrodes 32a and 32b are formed on one surface of the surface acoustic wave element substrate 31 so that two pairs of electrodes are alternately arranged. The comb-shaped electrodes 32a and 32b are formed by sputtering using Cu. However, the comb electrodes 32a and 32b may be formed using an electrode material other than Cu, such as Au, Ti, Ni, chromium (Cr), aluminum (Al), or by a film forming method other than sputtering. It may be formed.

  The inter-electrode distance d between the comb-shaped electrode 32a and the comb-shaped electrode 32b needs a value corresponding to the wavelength of the surface acoustic wave excited by the surface acoustic wave element. When the propagation velocity of the surface acoustic wave is v, the wavelength is λ, and the excitation frequency of the comb electrode is f, there is a relationship of v = f × λ and d = λ / 2. For example, in the case of lithium niobate, if the excitation frequency is 2.45 GHz, d needs to be about 0.8 μm.

  It is preferable that the electrode widths and distances between the adjacent comb electrodes 32a and 32b are equally spaced. In the above case, the width of each electrode is more preferably about 0.4 μm, which is half the distance d between the electrodes. Since the propagation velocity v varies depending on the material of the surface acoustic wave element substrate 31 that generates the surface acoustic wave, the inter-electrode distance d can be appropriately selected depending on an arbitrary material and frequency.

  The reflector 33 is formed on the surface of the surface acoustic wave element substrate 31 on which the comb-shaped electrodes 32a and 32b are formed to have substantially the same dimensions as the comb-shaped electrode 32a and the comb-shaped electrode 32b. The reflector 33 is formed by sputtering using Cu in the same manner as the comb electrodes 32a and 32b. However, the reflector 33 may be formed using an electrode material other than Cu, such as Au, Ti, Ni, chromium (Cr), and aluminum (Al), or formed by a film forming method other than sputtering. May be.

  The reflector 33 reflects the surface acoustic wave induced on the surface of the surface acoustic wave element substrate 31 by the high-frequency signal applied to the comb electrodes 32a and 32b, and is measurement information to the outside again through the comb electrodes 32a and 32b. Provided for transmitting a response signal. The principle of temperature measurement using a surface acoustic wave element will be described later.

  FIG. 3A is a plan view of the wireless temperature sensor 1, and FIG. 3B is a side view of the wireless temperature sensor 1.

  As shown in FIG. 3A, an antenna electrode layer 11 having a size of about 20 mm × 20 mm is provided on the upper surface of the wireless temperature sensor 1 of about 30 mm × 30 mm, that is, the surface of the lid 10. The external dimension of the wireless temperature sensor 1 is not limited to approximately 30 mm × 30 mm, and may be a size sufficient to mount the elastic surface element. Although the suitable outer dimensions of the antenna electrode layer 11 vary depending on the dielectric constant of the lid 10, the above dimensions (approximately 20 mm × 20 mm) are suitable when the relative dielectric constant of the lid 10 is about 9.8, for example. However, the dimensions of the antenna electrode layer 11 are not limited to this.

  As shown in FIG. 3B, the container 50 of the wireless temperature sensor 1 includes a lid 10 and a container body 20. The total thickness of the wireless temperature sensor 1 is approximately 8 mm, but is not limited to this and can be arbitrarily set.

  FIG. 4 is a cross-sectional view of the wireless temperature sensor 1 taken along line BB shown in FIG. In FIG. 3B, the boundary between the upper layer body 12 and the inner layer body 14 is indicated by a broken line so that the position of the BB cross section can be easily understood.

  As shown in FIG. 4, the GND electrode layer 13 is provided on the upper surface of the inner layer body 14, that is, on the surface facing the upper layer body 12, and the GND pattern opening 13w penetrates the antenna via hole 11h. It is provided in the center left of. The size of the GND electrode layer 13 is approximately 25 mm × 25 mm, but is not limited thereto. In order to further improve the high-frequency characteristics, it is preferable to make the shape of the GND electrode layer 13 larger.

  FIG. 5 is a diagram for explaining a temperature detection method by the wireless temperature sensor 1.

  The temperature detection method of the wireless temperature sensor 1 is based on the principle that the propagation speed of the surface acoustic wave propagating through the surface acoustic wave element substrate 31 depends on the temperature. In other words, the fact that the propagation time of the excitation surface acoustic wave Tw and the reflected surface acoustic wave Rw depends on the temperature of the surface acoustic wave element substrate 31 is utilized. Therefore, a calibration table of “propagation time versus surface acoustic wave element substrate temperature” is prepared in advance.

  First, an external device (not shown) transmits a high-frequency signal including an excitation frequency unique to the above-described antenna (a microstrip antenna including the antenna electrode layer 11, the upper layer body 12, the GND electrode layer 13, and the inner layer body 14). . As shown in FIG. 5, the high-frequency signal received by the antenna is applied to the comb-shaped electrode 32 a and the comb-shaped electrode 32 b through the bonding wires 35 a and 35 b to bring about an electro-mechanical conversion effect on the surface acoustic wave element substrate 31. That is, an excitation surface acoustic wave Tw determined by the inter-electrode distance d of the comb-shaped electrode is generated on the surface of the surface acoustic wave element substrate 31.

  The excitation surface acoustic wave Tw propagates on the surface of the surface acoustic wave element substrate 31, is reflected by the reflector 33, and returns to the comb electrode 32a and the comb electrode 32b as a reflected surface acoustic wave Rw. Next, part of the reflected surface acoustic wave Rw has a mechanical-electrical conversion effect on the surface acoustic wave element substrate 31 and is converted into a high-frequency signal, and a response signal is transmitted to the outside by the antenna. On the other hand, a part of the reflected surface acoustic wave Rw that has not been converted into a high-frequency signal is reflected by the comb-shaped electrode 32a and the comb-shaped electrode 32b, and travels on the surface acoustic wave element 31 toward the reflector 33 again. Hereinafter, the reflected surface acoustic wave Rw travels between the reflector 33 and the comb electrodes 32a and 32b on the surface acoustic wave element substrate 31, and a part thereof is gradually converted into a high-frequency signal by the comb electrodes 32a and 32b. As it is being attenuated.

  When the response signal transmitted by the antenna reaches the external device and the external device receives the response signal, the external device measures the time from when the high-frequency signal is transmitted until the response signal is received.

  After measuring the time from when the high frequency signal is transmitted until the response signal is received, the propagation time of the surface acoustic wave in the surface acoustic wave element is calculated from the time from when the high frequency signal is transmitted until the response signal is received. . The temperature of the surface acoustic wave element substrate 31 is obtained from the calculated propagation time based on a calibration table of “propagation time versus surface acoustic wave element substrate temperature” prepared in advance. Then, based on the temperature of the surface acoustic wave element substrate 31, the measurement temperature of the object on which the surface acoustic wave element substrate 31 is mounted is determined.

  FIG. 6 is a graph showing temporal changes in the reflected surface acoustic wave intensity Rwp in the surface acoustic wave element.

  In the graph shown in FIG. 6, the vertical axis indicates the intensity Rwp of the reflected surface acoustic wave Rw, and the horizontal axis indicates the propagation time T of the surface acoustic wave. Since the reflected surface acoustic wave Rw is repeatedly reflected between the comb electrode 32a and the comb electrode 32b and the reflector 33, the reflected surface acoustic wave Rw is observed at a plurality of times from time T1 to time T3. The intensity Rwp of the reflected surface acoustic wave Rw is advantageous in measurement because Rw1 at time T1, that is, the intensity of the reflected surface acoustic wave Rw detected first is the largest.

  FIG. 7 is a diagram for explaining a configuration of a temperature measurement system using the wireless temperature sensor 1.

  The temperature display device 40 transmits a high-frequency signal for temperature measurement to each of the plurality of wireless temperature sensors, receives a response signal of each wireless temperature sensor, and based on the calibration table, The measurement temperature is displayed.

  In the example illustrated in FIG. 7, the temperature display device 40 has one measurement temperature display unit, and the display unit detects a predetermined wireless temperature sensor selected from a plurality of wireless temperature sensors by a switch or the like. Display temperature. However, an individual display unit corresponding to each of the plurality of wireless temperature sensors may be provided in the temperature display device 40.

  In the example shown in FIG. 7, three wireless temperature sensors 1 </ b> A to 1 </ b> C are used, and the surface acoustic wave propagation distance L is designed to be different. Each wireless temperature sensor has a configuration table of “propagation time versus surface acoustic wave element substrate temperature”.

  A high frequency signal including an excitation frequency specific to each wireless temperature sensor is transmitted from the temperature display device 40. A response signal delayed by the propagation time of the surface acoustic wave is generated from each wireless temperature sensor. The wireless temperature sensors 1A to 1C are preferably attached in close contact with the measurement target so as not to generate a thermal gradient with the measurement target (not shown).

  By changing the surface acoustic wave propagation distance L, each wireless temperature sensor reciprocates the reflector 33 from the comb-shaped electrodes 32a and 32b over different propagation times. The wireless temperature sensors 1A to 1C can be distinguished from the difference in propagation time. Furthermore, the temperature of the measurement object (not shown) can be measured from the calibration table of “propagation time versus surface acoustic wave element substrate temperature” corresponding to each wireless temperature sensor from this propagation time.

  As described above, in addition to the method of designing the surface acoustic wave propagation distance L of each wireless temperature sensor to be different, the wireless frequency sensors may be designed to have different operating frequencies. This can be realized, for example, by changing the inter-electrode distance d of the comb electrodes 32a and 32b. By changing the inter-electrode distance d of the comb electrodes, each wireless temperature sensor is excited only by the unique high frequency signal f1 to high frequency signal f3. Therefore, by providing the temperature display device 40 with a frequency sweep function (not shown), the high-frequency signal f1 to the high-frequency signal f3 can be sequentially transmitted and received, and the temperature of the measurement object (not shown) can be measured.

  The method of using the temperature characteristics of the surface acoustic wave propagation time of the surface acoustic wave element substrate 31 for temperature measurement has been described above. However, an impedance modulation function according to temperature is provided in the reflector 33, and a temperature is measured based on the absolute value of the reflected surface acoustic wave intensity Rwp, or a resonance circuit is formed by a piezoelectric element or a ferroelectric element, and the temperature of the resonance frequency is set. A method using the characteristics is also effective.

  FIG. 8 is a flowchart showing an outline of the manufacturing process of the wireless temperature sensor 1.

  As shown in FIG. 8, the manufacturing process of the wireless temperature sensor 1 includes a container body assembly and high-temperature firing step ST1, a lid assembly and low-temperature firing step ST2, and a temperature detection element mounting and overall assembly step ST3.

  The container body assembly and high-temperature firing step ST1 is a process for forming the container body 20. The lid assembly and low-temperature firing step ST2 is a step of forming the lid 10. In the temperature detection element mounting and overall assembly process ST3, the temperature detection element 30 is electrically connected to the antenna electrode 11 and the GND electrode 13, and the temperature detection element 30 is fixed inside the container body 20 and the lid 10. The container body 20 and the lid 10 are bonded together. The container body assembly and high-temperature firing step ST1 and the lid assembly and low-temperature firing step ST2 may be performed in the reverse order or simultaneously.

  FIG. 9 is a diagram for explaining the container body assembly and the high-temperature firing step ST1 of the wireless temperature sensor 1. Hereinafter, the manufacturing method will be described using an example in which three wireless temperature sensors are manufactured at the same time and then separated into pieces.

  First, as shown in FIG. 9A, the main body bottom aggregate substrate 21b is formed using HTCC which is a first ceramic green sheet prepared by mixing and stirring a ceramic material, a glass filler, a binder, and a solvent. .

  Next, as shown in FIG. 9B, the main body side aggregate substrate 22b is formed using an HTCC ceramic green sheet, and a plurality of main body cavities 20c are provided in the main body side aggregate substrate 22b.

  Next, as shown in FIG. 9C, a high-temperature firing step is performed in which the main body bottom aggregate substrate 21b and the main body side aggregate substrate 22b are stacked and fired at about 1610 ° C. After firing, a collective container body 20b shown in FIG. 9 (d) is obtained.

  FIG. 10 is a diagram for explaining the lid assembly of the wireless temperature sensor 1 and the low-temperature firing step ST2.

  First, as shown in FIG. 10A, an upper layer aggregate substrate 12b is formed using a ceramic green sheet made of LTCC, and a plurality of antenna via holes 11h are provided using Cu.

  Next, as shown in FIG. 10B, as the antenna electrode forming step, the antenna electrode layer 11 that is a plurality of conductor patterns using Cu is printed on the upper assembly substrate 12b produced in FIG. 10A. Then, each antenna electrode layer 11 and each antenna via hole 11h are connected.

  Next, as shown in FIG. 10C, an inner layer aggregate substrate 14b is formed using a ceramic green sheet made of LTCC. Further, as a via hole forming step, a plurality of antenna via holes 11h for connecting to the antenna electrode layer 11 and a plurality of GND via holes 13h for connecting to the GND electrode layer 13 are formed on the inner layer aggregate substrate 14b using Cu. .

  Next, as shown in FIG. 10D, as the GND electrode forming step, the GND electrode layer 13 which is a plurality of conductor patterns using Cu is printed and formed on the produced inner layer aggregate substrate 14b. A GND pattern opening 13w is provided in a portion of the GND electrode layer 13 extending over the antenna via hole 11h, and the antenna via hole 11h is formed in the GND pattern opening 13w. Furthermore, each GND electrode layer 13 and each GND via hole 13h are connected.

  Next, as shown in FIG. 10 (e), the upper layer aggregate substrate 12b is placed on top of the inner layer aggregate substrate 14b, and each antenna via hole 11h is connected. A laminate of the inner layer aggregate substrate 14b and the upper layer aggregate substrate 12b is referred to as a second ceramic green sheet. Next, an electrode pad forming step is performed for forming a lid bonding pad 15a using Cu for each antenna via hole 11h and a lid bonding pad 15b using Cu for each GND via hole 13h. Then, as a low-temperature firing step, firing is performed at about 890 ° C. suitable for the upper-layer assembly substrate 12b and the inner-layer assembly substrate 14b, and the assembly lid 10b is obtained as shown in FIG.

  At the above-described firing temperature (about 890 ° C.), neither Ag nor Cu changes so as to substantially affect the antenna characteristics of the wireless temperature sensor.

  The upper layer aggregate substrate 12b and the inner layer aggregate substrate 14b are united by the above baking, but for the sake of convenience, a boundary is shown between the upper layer aggregate substrate 12b and the inner layer aggregate substrate 14b.

  FIG. 11 is a diagram for explaining the mounting of the temperature detection element 30 of the wireless temperature sensor 1 and the entire assembly process ST3.

  As shown in FIG. 11A, a plurality of temperature detection elements 30 are mounted on the cover mounting surface 15m of the collective cover 10b by a metal brazing method using an alloy of titanium (Ti) and nickel (Ni). In addition, the alloy used for a metal brazing method is not limited to these, You may use another metal.

  Further, the element bonding pad 34a of each temperature detecting element 30 and the lid bonding pad 15a of the collective lid 10b are connected by a bonding wire 35a. Similarly, the element bonding pad 34b of each temperature detection element 30 and the lid bonding pad 15b of the collective lid 10b are connected by a bonding wire 35b.

  Next, as shown in FIGS. 11B and 11C, the collective container body 20 b and the collective lid 10 b mounted with the temperature detection element 30 are placed so that the main body cavity 20 c is aligned with the position of the temperature detection element 30. By overlapping and joining, the collective wireless temperature sensor 1b is obtained.

  For example, the collective container body 20b and the collective lid 10b are formed by bonding gold (Au) and tin (Sn), which are bonding layers having high thermal conductivity, to the bonding surfaces and bonding them by eutectic bonding. Since Au and Sn have high thermal conductivity, the collective container body 20b and the collective lid 10b are thermally connected. In this way, by adopting a heat propagation band with good thermal conductivity at the joint location, the temperature detecting element 30 is thermally connected to the collective container body 20b while being fixed to the collective lid 10b. In addition, as a material and a joining method for joining the collection container main body 20b and the collection lid 10b, other joining methods such as a metal brazing method and a solid-phase joining method in which materials are pressure-fused at a high temperature are used. You can also.

  Next, as shown in FIG. 11C, the assembled wireless temperature sensor 1b that has been assembled is divided along the cutting line dc, and the separated wireless temperature sensor 1 shown in FIG. 11D is obtained. In the above example, the method of manufacturing three wireless temperature sensors at a time has been described. However, the number of wireless temperature sensors manufactured at a time can be further increased.

The structure of the wireless temperature sensor 1 is that the constituent material of the container body 20 which is the first ceramic substrate is Al ₂ O ₃ having a high firing temperature of 1610 ° C. and a high thermal conductivity of 18 W / (m · K). Used as. Therefore, the temperature measurement responsiveness of the wireless temperature sensor 1 is improved.

The second ceramic substrate (the upper layer body 12 and the inner layer body 14) of the wireless temperature sensor 1 is, for example, LTCC like a material in which Al ₂ O ₃ is added to CaO—Al ₂ O ₃ —SiO ₂ —B ₂ O _3. It consists of Since the firing temperature of the LTCC is 890 ° C., it is possible to use Cu having a very low electric resistance of 1.6 μΩcm as a conductor.

  This makes it possible to take advantage of the low characteristics of the LTCCC dielectric loss tangent (tan δ) of 0.0003, thereby further improving the high-frequency characteristics and thus the antenna characteristics. Further, since eutectic bonding is used for the entire assembly, there is no influence on each element, and the wireless temperature sensor 1 that improves both the responsiveness of temperature measurement and the transmission / reception efficiency can be provided.

  FIG. 12 is a diagram for explaining the structure of another wireless temperature sensor 2.

  The wireless temperature sensor 2 is a modification of the wireless temperature sensor 1 described above. In the following, the wireless temperature sensor 2 will be described with respect to differences from the wireless temperature sensor 1, and description of points similar to the wireless temperature sensor 1 will be omitted as appropriate.

  The difference between the wireless temperature sensor 2 shown in FIG. 12 and the wireless temperature sensor 1 shown in FIG. 1 is the presence or absence of the first wiring electrode and the second wiring electrode, and the others are the same.

  As shown in FIG. 12, in the wireless temperature sensor 2, a first wiring electrode 17 a and a second wiring electrode 17 b are provided below the inner layer body 14.

  The first wiring electrode 17a and the second wiring electrode 17b are provided on the lid mounting surface 15ma on which the temperature detection element 30 of the inner layer body 14 is mounted using Cu. The first wiring electrode 17a and the second wiring electrode 17b are not limited to Cu, and other metals may be used.

  The second wiring electrode 17b has a size of approximately 25 mm × 25 mm, and is a heat conductive layer thermally connected to the container body 20 at the end. The second wiring electrode 17b is provided with a wiring electrode layer opening 17w for penetrating the first wiring electrode 17a.

  The temperature detection element 30 is metal brazed so as to be thermally connected to the second wiring electrode 17b. The element bonding pad 34a of the temperature detection element 30 is electrically connected to the first wiring electrode 17a via the bonding wire 35a. The element bonding pad 34b of the temperature detecting element 30 is electrically connected to the second wiring electrode 17b via the bonding wire 35b.

  The lid assembly and low-temperature firing process of the wireless temperature sensor 2 will be described with reference to FIG. In addition, since other processes (a container main body assembly and a high temperature baking process, a temperature detection element mounting, and a whole assembly process) are the same as the wireless temperature sensor 1 among the manufacturing methods of the wireless temperature sensor 2, description is abbreviate | omitted. .

  First, as shown in FIG. 13A, an upper assembly substrate 12b having an antenna electrode layer 11 and an antenna via hole 11h is formed. Since the manufacturing method of the upper-layer assembly board 12b is the same as that of the wireless temperature sensor 1, the description thereof is omitted.

  Next, as shown in FIG. 13B, the first wiring electrode 17a and the second wiring electrode 17b are formed on the lower surface of the inner layer assembly substrate 14Ab having the GND electrode layer 13, the GND via hole 13h, and the antenna via hole 11h. Form.

  Next, as shown in FIG. 13C, the second ceramic green sheet in which the upper layer aggregate substrate 12b and the inner layer aggregate substrate 14Ab are laminated so that each antenna via hole 11h is connected is fired at about 890 ° C. The collective lid 10Ab is obtained.

  In the wireless temperature sensor 2, a wiring electrode layer 17 having a first wiring electrode 17 a and a second wiring electrode 17 b is provided below the inner layer body 14. The second wiring electrode 17 b is a heat conductive layer that is thermally connected to each of the container body 20 and the temperature detection element 30. Therefore, the heat of the measurement object transmitted to the container body 20 can be transmitted from the container body 20 to the temperature detection element 30 via the second wiring electrode 17b. Therefore, heat is prevented from being dissipated in the lid 10A, and the thermal responsiveness as the wireless temperature sensor 2 is further improved.

  In the wireless temperature sensor 2, since the temperature detection element 30 is connected to the second wiring electrode 17b, noise resistance is improved, and characteristics and reliability as a temperature sensor are improved.

  FIG. 14 is a diagram for explaining the structure of still another wireless temperature sensor 3.

  The wireless temperature sensor 3 is a modification of the wireless temperature sensor 2 described above. In the following, the wireless temperature sensor 3 will be described with respect to points different from the wireless temperature sensor 2, and description of points similar to the wireless temperature sensor 2 will be omitted as appropriate.

  The difference between the wireless temperature sensor 3 shown in FIG. 14 and the wireless temperature sensor 2 shown in FIG. 12 is the position of the GND via hole, and the others are the same.

  As shown in FIG. 14, in the wireless temperature sensor 3, the temperature detection element 30 is fixed on the GND via hole 13h. Here, “fixed on the GND via hole 13h” includes the case where the position of the approximate center of the temperature detection element 30 is equal to the position of the approximate center of the GND via hole 13h, as shown in FIG. Not limited to this. For example, the case where the position of the approximate center of the GND via hole 13h is included in the region of the temperature detection element 30 and the case where the region of the GND via hole 13h is included in the region of the temperature detection element 30 are also included.

  The position of the GND via hole 13h is not limited to the vicinity of the approximate center of the lid 10A, but can be arbitrarily arranged. The temperature detection element 30 can be “fixed on the GND via hole 13h” in accordance with the position of the GND via hole 13h.

  FIG. 15A is a cross-sectional view schematically showing a propagation path of heat from a measurement object (not shown) of the wireless temperature sensor 2. FIG. 15B is a cross-sectional view schematically showing a propagation path of heat from a measurement object (not shown) of the wireless temperature sensor 3. In FIG. 15A and FIG. 15B, hatching representing a cross section is omitted for the sake of explanation.

  As shown in FIG. 15A, in the wireless temperature sensor 2, as shown in H, the heat transferred from the measurement object (not shown) to the container main body 20 moves inside the container main body 20, and eventually the second wiring. It communicates with the electrode 17b. The heat transferred to the second wiring electrode 17b moves toward the temperature detection element 30 in the second wiring electrode 17b, but a part of the heat passes through the GND via hole 13h as shown in H1. Move towards the body 12. This is because the thermal resistance of the GND via hole 13h made of Cu is low.

  As shown in FIG. 15B, in the wireless temperature sensor 3, as shown at H, the heat transferred from the measurement object (not shown) to the container main body 20 moves inside the container main body 20, and eventually the second wiring. It is transmitted to the electrode 17b. The heat transferred to the second wiring electrode 17b moves inside the second wiring electrode 17b toward the temperature detection element 30 as indicated by H2. At this time, since there is no GND via hole 13h having a low thermal resistance in the middle of the path to the temperature detection element 30, most of the heat flows into the temperature detection element 30 via the second wiring electrode 17b.

  As described above, in the wireless temperature sensor 3, since the temperature detection element 30 is fixed on the GND via hole 13h, it is possible to reduce the amount of heat that moves to the inside of the lid 10 by the via hole. Therefore, in the wireless temperature sensor 3, the responsiveness of the temperature measurement is improved and the fluctuation of the antenna characteristics due to the influence of heat is reduced.

  FIG. 16 is a diagram for explaining the structure of still another wireless temperature sensor 4.

  The wireless temperature sensor 4 is a modification of the wireless temperature sensor 2 described above. Hereinafter, the wireless temperature sensor 4 will be described with respect to differences from the wireless temperature sensor 2, and description of points similar to the wireless temperature sensor 2 will be omitted as appropriate.

  The difference between the wireless temperature sensor 4 shown in FIG. 16 and the wireless temperature sensor 2 shown in FIG. 12 is the presence or absence of a protective layer, and the others are the same.

As shown in FIG. 16, in the wireless temperature sensor 4, a protective layer 16 is provided on the antenna electrode layer 11 and the upper layer body 12. The protective layer 16 is formed of a material obtained by adding Al ₂ O ₃ to CaO—Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ , similarly to the upper layer body 12 and the inner layer body 14. However, the protective layer 16 may be formed of another LTCC, or may be formed of a film such as SiO ₂ or TiO ₂ .

  Hereinafter, the lid assembly and low-temperature firing process of the wireless temperature sensor 4 will be described with reference to FIG.

  First, as shown in FIG. 17A, the upper layer aggregate substrate 12b and the inner layer aggregate substrate 14Ab are laminated together.

Next, as shown in FIG. 17 (b), an aggregate protective layer 16b is formed using an LTCC ceramic green sheet made of a material obtained by adding Al ₂ O ₃ to CaO—Al ₂ O ₃ —SiO ₂ —B ₂ O _3. Form.

  Next, as shown in FIG. 17C, the collective protective layer 16b is placed on the laminate prepared in FIG. 17A and baked at about 890 ° C. to obtain the collective lid 10Pb.

When the protective layer 16 is formed of a film such as SiO ₂ or TiO ₂ , the protective layer 16 is directly formed on the upper layer aggregate substrate 12b prepared in FIG. 17A by sputtering or the like. It may be formed.

  In the wireless temperature sensor 4, the antenna electrode layer 11, which is a metal body, is protected by the protective layer 16, thereby improving anti-static properties and reducing abnormal operation of the sensor due to adhesion of conductive foreign matters such as metal fragments. Therefore, durability and reliability are improved.

  FIG. 18 is a diagram for explaining the structure of still another wireless temperature sensor 5.

  The wireless temperature sensor 5 is a modification of the wireless temperature sensor 1 described above. Hereinafter, the wireless temperature sensor 5 will be described with respect to differences from the wireless temperature sensor 1, and description of points similar to the wireless temperature sensor 5 will be omitted as appropriate.

  The difference between the wireless temperature sensor 5 shown in FIG. 18 and the wireless temperature sensor 1 shown in FIG. 1 is the point of the mounting method of the temperature detection element and the point of contact between the temperature detection element and the container body. It is.

  As shown in FIG. 18, the temperature detection element 30 is flip-chip mounted on the lid 10 with the surface on which the comb-shaped electrodes 32 a and 32 b and the reflector 33 are provided facing the lid 10. The element bonding pad 34a is connected to the lid bonding pad 15a via the gold bump 36a, and the element bonding pad 34b is connected to the lid bonding pad 15b via the gold bump 36b.

  As shown in FIG. 18, in the wireless temperature sensor 4, the surface opposite to the surface facing the lid 10 of the temperature detection element 30 is in contact with the container body 20. However, even if the temperature detection element 30 and the container body 20 are not in contact with each other, they may be close to each other to the extent that direct heat conduction occurs between them. The location of the temperature detection element 30 in contact with or close to the container body 20 and the distance between the temperature detection element 30 and the container body 20 in the case of proximity are arbitrarily designed as long as direct heat conduction occurs between them. can do.

  Hereinafter, the temperature detection element mounting process of the wireless temperature sensor 5 will be described with reference to FIG. The other steps of the manufacturing method of the wireless temperature sensor 5 (container body assembly and high-temperature firing step, lid assembly and low-temperature firing, and overall assembly step) are the same as those of the wireless temperature sensor 1, and thus description thereof is omitted. . Note that the thickness of the space inside the container body 20 is set to a length corresponding to the height from the mounting surface 15 m to the surface opposite to the lid 10 of the temperature detection element 30. Although the manufacturing process of one wireless temperature sensor will be described below for convenience of explanation, it is also possible to use a manufacturing method in which a plurality of wireless temperature sensors are formed at the same time and then separated.

  First, as shown in FIG. 19A, a gold bump 36 a is formed on the element bonding pad 34 a of the temperature detection element 30, and a gold bump 36 b is formed on the element bonding pad 34 b of the temperature detection element 30.

  Next, as shown in FIG. 19B, the temperature detection element 30 is inverted, and the temperature detection is performed so that the gold bump 36a contacts the lid bonding pad 15a and the gold bump 36b contacts the lid bonding pad 15b. The element 30 is placed on the lid mounting surface 15m.

  Next, by bonding and bonding the bonding pads (15a, 15b, 34a, 34b) and the gold bumps 36a, 36b by ultrasonic vibration, as shown in FIG. Is mounted on the lid 10. Thus, the temperature detecting element mounting process in the wireless temperature sensor 45 is completed.

  In the wireless temperature sensor 5, the temperature detection element 30 and the container body 20 are in contact with each other or close to each other to the extent that direct heat conduction occurs between them. Therefore, the heat transferred from the measurement object to the container main body 20 can directly move from the container main body 20 to the temperature detection element 30 as indicated by H3 in FIG. Therefore, the responsiveness of temperature measurement in the wireless temperature sensor is improved.

  FIG. 20 is a view for explaining the structure of still another wireless temperature sensor 6, and FIG. 21 is a view of the wireless temperature sensor 6 as viewed from the direction 6D in FIG.

  The wireless temperature sensor 6 is a modification of the above-described wireless temperature sensor 5. Hereinafter, the wireless temperature sensor 6 will be described with respect to points different from the wireless temperature sensor 5, and description of points similar to the wireless temperature sensor 5 will be omitted as appropriate.

  The difference between the wireless temperature sensor 6 shown in FIG. 20 and the wireless temperature sensor 5 shown in FIG. 18 is the presence or absence of an opening provided on the side opposite to the side bonded to the lid of the container body. It is.

  The container body 20 </ b> A of the wireless temperature sensor 6 has a rectangular opening 20 </ b> AW on the side opposite to the surface facing the lid 10. Therefore, as shown in FIG. 21, the temperature detection element 30 is exposed to the outside.

  The shape of the opening 20AW is not limited to a rectangular shape, and may be an arbitrary shape such as a circular shape, a polygonal shape, or an irregular shape. The container body 20A can be obtained, for example, by creating the container body without using the body bottom aggregate substrate 21b described with reference to FIG. 9C, but can also be created by other methods. .

  A sealing resin 70 is provided at an edge of the temperature detection element 30 so as to fill a space between the temperature detection element 30 and the lid 10, and hermetic sealing is performed by the lid 10, the temperature detection element 30, and the sealing resin 70. The formed space 6S is formed. The space 6S includes comb electrodes 32a and 32b and a reflector 33 therein.

  In the wireless temperature sensor 6, the opening 20 </ b> AW is provided on the side opposite to the side of the container body 20 </ b> A that is bonded to the lid 10, and the temperature detection element 30 is exposed to the outside. It becomes possible to arrange | position near the measurement object. Therefore, the heat of the measurement object is easily transmitted to the temperature detection element 30, and the thermal responsiveness of the wireless temperature sensor is improved.

  In the wireless temperature sensor 6, the comb-shaped electrodes 32 a and 32 b and the reflector 33 are included in the space 6 </ b> S hermetically sealed with the sealing resin 70, so that an external gas or fluid cannot enter the space 6 </ b> S. Therefore, the stability of the antenna characteristics of the wireless temperature sensor is improved. The space 6S may be a vacuum, and when the space 6S is a vacuum, the stability of the antenna characteristics of the wireless temperature sensor is further improved.

  FIG. 22 is a diagram for explaining the structure of still another wireless temperature sensor 7.

  The wireless temperature sensor 7 is a modification of the wireless temperature sensor 5 described above. In the following, the wireless temperature sensor 7 will be described with respect to differences from the wireless temperature sensor 5, and the same points as the wireless temperature sensor 5 will not be described as appropriate.

  The difference between the wireless temperature sensor 7 shown in FIG. 22 and the wireless temperature sensor 5 shown in FIG. 18 is the presence or absence of a heat conductor, and the others are the same.

  As shown in FIG. 22, the wireless temperature sensor 7 further includes a heat conductor 60 disposed between the temperature detection element 30 and the container body 20. The heat conductor 60 is thermally connected to both the temperature detection element 30 and the container body 20, and is bonded by, for example, a highly heat conductive resin. Alternatively, the heat conductor 60 may be sandwiched between the temperature detection element 30 and the container body 20 even if it is not bonded to the temperature detection element 30 and the container body 20.

  The thermal conductor 60 is formed of a silver paste having a high thermal conductivity. However, the heat conductor 60 is not limited to the silver paste, and may be formed of a material having high thermal conductivity such as an epoxy resin, a silicon resin, a ceramic material, a metal, and a heat resistant resin.

  Furthermore, it is preferable that the thermal conductor 60 has a small coefficient of thermal expansion in order to maintain the airtightness of the lid 10 and the container body 20.

  Hereinafter, the temperature detection element mounting and the entire assembly process of the wireless temperature sensor 7 will be described with reference to FIG. In addition, since the other process (a container main body assembly and a high temperature baking process, and a lid assembly and a low temperature baking process) of the manufacturing method of the wireless temperature sensor 7 is the same as that of the wireless temperature sensor 1, description is abbreviate | omitted.

  First, as shown in FIG. 23A, the temperature detection element 30 is flip-chip mounted on the lid 10. In addition, since the said process is the same as the process mentioned above using Fig.19 (a)-(d), description is abbreviate | omitted.

  Next, as shown in FIG. 23 (b), a heat conductor 60, which is a silver paste formed by firing a binder in which silver particles are mixed, on the surface opposite to the lid 10 of the temperature detecting element 30. Are bonded using a highly heat conductive resin.

  Next, as shown in FIG. 23C, the container body 20 is overlapped and joined to the lid 10 on which the temperature detection element 30 is mounted so that the body cavity 20c is aligned with the position of the temperature detection element 30. The wireless temperature sensor 7 shown in FIG. Note that the bonding method is the same as the method described above with reference to FIGS.

  Unlike the above-described method, after bonding the heat conductor 60 to the bottom of the container body 20, the lid 10 and the container body 20 are overlapped and bonded so that the heat conductor 60 contacts the temperature detection element 30, A wireless temperature sensor 7 may be obtained.

  In the wireless temperature sensor 7, since the heat conductor 60 is disposed between the temperature detection element 30 and the container body 20, the heat of the measurement object transmitted to the container body 20 is detected via the heat conductor 60. It is transmitted to the element 30. Therefore, the heat of the measurement object is easily transmitted to the temperature detection element 30, and the thermal responsiveness of the wireless temperature sensor is improved.

  FIG. 24 is a diagram for explaining the structure of still another wireless temperature sensor 8.

  The wireless temperature sensor 8 is a modification of the above-described wireless temperature sensor 5. Hereinafter, the wireless temperature sensor 8 will be described with respect to points different from the wireless temperature sensor 5, and description of points similar to the wireless temperature sensor 5 will be omitted as appropriate.

  The difference between the wireless temperature sensor 8 shown in FIG. 24 and the wireless temperature sensor 5 shown in FIG. 18 is in the structure of the container body, and the others are the same.

Similar to the container body 20 of the wireless temperature sensor 1, the container body 20B of the wireless temperature sensor 8 is formed of Al ₂ O ₃ which is HTCC. However, unlike the container body 20, the container body 20 </ b> B has a porous structure that is a structure that allows gas or fluid to pass through. For example, when a part of the container body 20B is formed of metal, a mesh structure may be adopted as a structure that allows gas or fluid to pass through. Thus, as a structure of the container main body 20B, a structure capable of allowing a gas or a fluid to pass can be designed according to the substance forming the container main body 20B.

  A sealing resin 70 is provided on the edge of the temperature detection element 30 of the wireless temperature sensor 8 so as to fill between the temperature detection element 30 and the lid 10. The lid 10, the temperature detection element 30, and the sealing resin A space 8S hermetically sealed by 70 is formed. The space 8S includes comb electrodes 32a and 32b and a reflector 33 therein.

  The wireless temperature sensor 8 has a structure that allows the container body 20B to pass gas or fluid. Therefore, as shown at H4 in FIG. 24, the gas or fluid around the wireless temperature sensor 8 passes through the container body 20B and enters and exits the space surrounded by the lid 10 and the container body 20B (excluding the space 8S). It becomes possible to do. Therefore, since the temperature detecting element 30 can directly detect the temperature of the gas or fluid, the wireless temperature sensor 8 can more accurately measure the environmental temperature (atmosphere temperature).

  In the wireless temperature sensor 8, the comb electrodes 32 a and 32 b and the reflector 33 are included in the space 7 </ b> S hermetically sealed with the sealing resin 70. Therefore, the gas or fluid that passes through the container body 20B and flows into the space surrounded by the lid 10 and the container body 20B cannot enter the space 8S. Therefore, the stability of the antenna characteristics of the wireless temperature sensor is improved. The space 8S may be vacuum, and when the space 8S is vacuum, the stability of the antenna characteristics of the wireless temperature sensor is further improved.

  The above-described wireless temperature sensors 1 to 8 can be applied to devices that require remote sensing of temperature measurement.

  It should be understood by those skilled in the art that various changes, substitutions, and modifications can be made thereto without departing from the spirit and scope of the present invention, and the embodiments may be appropriately combined.

1, 2, 3, 4, 5, 6, 7, 8 Wireless temperature sensor 1b Collective wireless temperature sensor 10, 10A, 10P Lid 11 Antenna electrode 11h Antenna via hole 12 Upper layer 12b Upper layer aggregate substrate 13 GND electrode 13h GND via hole 13w GND pattern opening 14 Inner layer 14b Inner layer assembly substrate 15a, 15b Lid bonding pad 15m, 15ma Cover mounting surface 16 Protective layer 16b Collective protection layer 17w Wiring electrode layer opening 17a First wiring electrode 17b Second wiring electrode 20 20A, 20B Container body 20AW Opening 20b Collecting container body 20c Body cavity 21b Body bottom assembly board 22b Body side assembly board 30 Temperature detection element 31 Surface acoustic wave element substrate 32a, 32b Comb electrode 33 Reflector 34a, 34b Element bond 35a Bonding wire 40 Temperature display device 50, 50A, 50P Container Tw Excited surface acoustic wave Rw Reflected surface acoustic wave Rwp Reflected surface acoustic wave intensity T1, T2, T3 Time d, d1, d2, d3 Distance between electrodes f1, f2, f3 High-frequency signal t Propagation time ST1 Container body assembly and high-temperature firing process ST2 Lid assembly and low-temperature firing process ST3 Temperature detection element mounting and overall assembly process dc cutting line

Claims (22)

A method for manufacturing a wireless temperature sensor, comprising:
Prepare a first ceramic green sheet and a second ceramic green sheet,
Firing the first ceramic green sheet having a higher thermal conductivity than the second ceramic green sheet to form a container body;
An antenna electrode and a GND electrode are disposed on the second ceramic green sheet, and the second ceramic green sheet on which the antenna electrode and the GND electrode are disposed is lower in firing temperature than the first ceramic green sheet. Baking to form a lid with an antenna;
Electrically connecting a temperature detection element to the antenna electrode and the GND electrode;
Bonding the container body and the lid so that the temperature detection element is fixed inside the container body and the lid;
A method for manufacturing a wireless temperature sensor.   The method for manufacturing a wireless temperature sensor according to claim 1, wherein the container body and the lid are bonded together so that the temperature detection element contacts the inside of the container body.   The method of manufacturing a wireless temperature sensor according to claim 1, wherein the container body has an opening on a side opposite to a side bonded to the lid.   The step of bonding the container body and the lid is performed by bonding the container body and the lid so as to dispose a heat conductor between the container body and the temperature detection element. Manufacturing method for wireless temperature sensor.   The method of manufacturing a wireless temperature sensor according to claim 1, wherein the container body has a porous structure or a mesh structure. The step of forming the lid includes
A conductor pattern to be the antenna electrode is disposed on one surface of the second ceramic green sheet,
A conductor pattern to be the GND electrode is disposed on the inner layer of the second ceramic green sheet,
Forming a first via hole in conduction with the antenna electrode and a second via hole in conduction with the GND electrode in the second ceramic green sheet;
On the other surface of the second ceramic green sheet, a first electrode pad electrically connected to the first via hole and a second electrode pad electrically connected to the second via hole are formed.
The manufacturing method of the wireless temperature sensor as described in any one of Claims 1-5.   The step of forming the lid includes heat that is electrically connected to the second electrode pad and thermally connected to the temperature detection element and the container body on the other surface of the second ceramic green sheet. The manufacturing method of the wireless temperature sensor of Claim 6 which forms a conductive layer.   The method of manufacturing a wireless temperature sensor according to claim 7, further comprising a step of fixing the temperature detection element on the second via hole on the heat conductive layer.   The manufacturing method of the wireless temperature sensor as described in any one of Claims 1-8 which further has the process of forming the protective layer which covers the said antenna electrode on said 2nd ceramic green sheet. A container body formed from a first ceramic substrate;
A lid formed of a second ceramic substrate having a firing temperature lower than that of the first ceramic substrate;
An antenna,
A temperature detection element,
The first ceramic substrate has a higher thermal conductivity than the second ceramic substrate,
The antenna includes an antenna electrode and a GND electrode formed integrally with the lid,
The temperature detection element is electrically connected to the antenna electrode and the GND electrode, and is fixed inside the container body and the lid by bonding the container body and the lid.
A wireless temperature sensor characterized by that.   The wireless temperature sensor according to claim 10, wherein the temperature detection element is fixed inside the container body and the lid so as to contact the inside of the container body.   The wireless temperature sensor according to claim 10, wherein the container body has an opening on a side opposite to a side bonded to the lid.   The wireless temperature sensor according to claim 10, further comprising a heat conductor disposed between the container body and the temperature detection element.   The wireless temperature sensor according to claim 10, wherein the container body has a porous structure or a mesh structure. The first ceramic substrate is HTCC (High Temperature Coated Ceramics),
15. The wireless temperature sensor according to claim 10, wherein the second ceramic substrate is LTCC (Low Temperature Coated Ceramics).   The wireless temperature sensor according to any one of claims 10 to 15, wherein a material of the antenna electrode of the antenna is silver (Ag) or copper (Cu).   The wireless temperature sensor according to any one of claims 10 to 16, wherein the container body and the lid are thermally connected, and the temperature detection element and the lid are thermally connected.   The wireless temperature sensor according to any one of claims 10 to 17, wherein the antenna electrode is formed on a surface of the second ceramic substrate, and the GND electrode is formed on an inner layer of the second ceramic substrate. Further comprising a first wiring electrode and a second wiring electrode formed on the back surface of the second ceramic substrate;
The first wiring electrode is electrically connected to the temperature detection element and the antenna electrode, respectively.
The wireless temperature sensor according to any one of claims 10 to 18, wherein the second wiring electrode is electrically connected to the temperature detection element and the GND electrode, respectively.   The wireless temperature sensor according to claim 19, wherein the second wiring electrode is thermally connected to the temperature detection element and the container body. A via hole formed in the second ceramic substrate and electrically connected to the GND electrode and the second wiring electrode;
The wireless temperature sensor according to claim 20, wherein the temperature detection element is fixed on the via hole on the second wiring electrode.   The wireless temperature sensor according to any one of claims 10 to 21, further comprising a protective layer covering the antenna electrode.

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