JP2008085751A - Surface acoustic wave device and sealed state judging method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface acoustic wave device and sealed state judging method thereof in which miniaturization can be attained and a sealed state can be easily judged. <P>SOLUTION: In the surface acoustic wave device, IDT electrodes 21a, 21b, pad electrodes 22a, 22b, 22c, 22d for IDT electrodes, a monitoring pattern 23 constituted of a band-like conductor and monitoring pad electrodes 24a, 24b are formed on a lower surface of a piezoelectric substrate 11 and pad electrodes, and a surface acoustic wave element 10 formed with a protecting film 31 exposing the pad electrodes 22a-22d for IDT electrodes, the monitoring pattern 23 and the monitoring pad electrodes 24a, 24b is mounted on a mounting base. The IDT electrodes 21a, 21b and the monitoring pattern 23 are air-tightly sealed in the same sealing space by a sealing material. Since the sealed state can be judged from a change in electric resistance caused by corrosion of the monitoring pattern 23, miniaturization can be attained and the sealed state can be easily judged. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface acoustic wave device and a sealing state determination method thereof, and more particularly to a surface acoustic wave device that can be miniaturized and that can easily determine a sealing state and a sealing state determination method thereof.

  Surface acoustic wave devices are widely used as electronic components such as resonators, filters, duplexers and the like used in electronic devices such as communication devices. However, along with recent miniaturization of electronic devices, However, there is an increasing demand for miniaturization.

In order to ensure the reliability of surface acoustic wave devices, it is necessary to seal the surface acoustic wave excitation part and propagation part in a sealed space. In order to judge the sealing state, a bubble leak test or helium leak is required. A test has been conducted. The bubble leak test is performed by placing the surface acoustic wave device in a high-temperature liquid and visually confirming the bubbles generated by the gas in the sealed space of the surface acoustic wave device expanding and leaking outside. Judge that the state is bad. In the helium leak test, the pressure in the chamber containing the surface acoustic wave device is reduced, and then helium gas is injected and pressurized to infiltrate the helium gas into the sealed space of the surface acoustic wave device in a poorly sealed state. By detecting the helium gas leaking from the sealing space of the surface acoustic wave device after discharging the helium gas in the surface with a detector, it is determined that the sealing state is defective (for example, see Patent Document 1). reference.).
JP-A-3-2540

  However, each of the above-described methods for determining the sealing state has problems, and it has been difficult to adapt to a small surface acoustic wave device that has been increasingly demanded in recent years.

  For example, when the surface acoustic wave device is miniaturized and the internal sealed space is also miniaturized, the amount of gas confined in the sealed space is reduced. This makes it difficult for the gas confined in the sealed space to leak out of the sealed space when the bubble leak test is performed. It becomes difficult to judge the state.

  Further, as described in Patent Document 1, helium gas used for the helium leak test has a property of adsorbing to a resin such as an epoxy resin. Many recent surface acoustic wave devices have a structure in which a surface acoustic wave element mounted on a substrate is sealed with a resin for miniaturization, and a helium leak test was performed on such a surface acoustic wave element. In this case, since a large amount of helium gas adsorbed on the sealing resin is gradually released from the resin over a long period of time, by detecting the helium gas released from this resin, the sealing state is not defective. In both cases, there was a problem that it was judged as a sealing failure.

  The present invention has been devised in view of such problems in the prior art, and an object of the present invention is to provide a surface acoustic wave device that can be miniaturized and that can easily determine the sealing state. . Another object of the present invention is to provide a method for determining the sealing state of a surface acoustic wave device that can easily determine the sealing state of the surface acoustic wave device of the present invention.

  The surface acoustic wave device of the present invention has an IDT electrode, a pad electrode for an IDT electrode connected to the IDT electrode, a monitor pattern composed of a strip-shaped conductor, and both ends of the monitor pattern. And a pair of monitor pad electrodes formed, and an elastic surface on which the IDT electrode pad electrode, the monitor pattern, and the monitor pad electrode are exposed to form a protective film covering the IDT electrode The wave element includes an IDT electrode terminal electrode corresponding to the IDT electrode pad electrode, a monitor terminal electrode corresponding to the monitor pad electrode, and a monitor external electrode connected to the monitor terminal electrode on the insulating substrate. On the formed mounting substrate, the IDT electrode pad electrode and the IDT electrode terminal electrode, and the monitor And the monitor terminal electrode are connected by connecting conductors, and the IDT electrode and the monitor pattern are hermetically sealed in the same sealing space by a sealing member. It is a feature.

  The surface acoustic wave device of the present invention is characterized in that, in the above configuration, the monitoring pattern is formed of the same material and the same thickness as the IDT electrode.

  Furthermore, in the surface acoustic wave device according to the invention, in the above configuration, one of the pair of external monitor electrodes is connected to a ground potential, and the monitor pad electrode connected to the external monitor electrode is the IDT electrode. It is characterized by being connected to a part connected to the ground potential.

  Furthermore, the surface acoustic wave device according to the present invention is characterized in that, in the above-described configuration, the monitor pattern has a narrow width portion that is narrower than the width of other band-shaped portions.

  Furthermore, the surface acoustic wave device of the present invention is characterized in that, in the above configuration, the plurality of narrow portions are connected in parallel.

  According to the sealing state determination method for a surface acoustic wave device of the present invention, the surface acoustic wave device configured as described above is a gas or liquid that corrodes the monitor pattern after measuring the electrical resistance between the pair of monitor external electrodes. Leave it in the inside, and then measure the electrical resistance between the pair of external electrodes for monitoring again, and seal the one where the measured value of the electrical resistance after leaving is increased compared to the measured value before leaving Is determined to be defective.

  The surface acoustic wave device according to the present invention is connected to the IDT electrode, the pad electrode for the IDT electrode connected to the IDT electrode, the monitor pattern composed of a strip-shaped conductor, and both ends of the monitor pattern on one main surface of the piezoelectric substrate. A surface acoustic wave device in which a pair of monitor pad electrodes are formed and a protective film covering the IDT electrode by exposing the IDT electrode pad electrode, the monitor pattern, and the monitor pad electrode is formed on an insulating substrate. The IDT electrode terminal electrode corresponding to the IDT electrode pad electrode, the monitor terminal electrode corresponding to the monitor pad electrode, and the monitor external electrode connected to the monitor terminal electrode are formed on the mounting substrate. Electrode pad electrode and IDT electrode terminal electrode, and monitor pad electrode and monitor terminal electrode, respectively Together they are mounted connected by connection conductors, IDT electrodes and the monitor pattern is hermetically sealed in the same sealing space by the sealing member. According to the surface acoustic wave device of the present invention having such a configuration, a pair of monitor externals respectively connected to both ends of a monitor pattern made of a strip-shaped conductor hermetically sealed in the same sealed space as the IDT electrode. Since the electrodes have electrodes, if the gas or liquid that corrodes the monitor pattern enters the sealed space when the sealing state is poor, the monitor pattern corrodes and the electrical resistance of the monitor pattern Therefore, the quality of the sealed state can be determined by measuring the presence or absence of a change in electrical resistance between the pair of monitor external electrodes connected to both ends of the monitor pattern. As a result, even when resin is used as the sealing member, the sealing state can be easily determined unlike the helium leak test, and even when the sealing space is small, the sealing state is easily different from the bubble leak test. Therefore, it is possible to obtain a surface acoustic wave device that can be miniaturized and that can easily determine the sealed state. Furthermore, since the protective film covering the IDT electrode is formed by exposing the monitor pattern, the protective film prevents the occurrence of an electrical short circuit caused by the contact of the conductive foreign matter with the IDT electrode, and the monitor. Since the gas or liquid that corrodes the pattern for use can be brought into contact with the monitor pattern, the surface acoustic wave that prevents the electrical short circuit of the IDT electrode due to the contact of the conductive foreign matter and can easily determine the sealing state A device can be obtained.

  Further, according to the surface acoustic wave device of the present invention, when the monitor pattern is formed of the same material and the same thickness as the IDT electrode, the monitor pattern can be formed simultaneously with the IDT electrode. A surface acoustic wave device that can be manufactured by a simple process can be obtained.

  Furthermore, according to the surface acoustic wave device of the present invention, one of the pair of monitor external electrodes is connected to the ground potential, and the monitor pad electrode connected to the monitor external electrode is connected to the ground potential of the IDT electrode. When connected to a portion that is connected to the ground potential of the IDT electrode, the monitor pad electrode connected to the portion connected to the ground potential of the IDT electrode can also be used as the pad electrode for the IDT electrode connected to the ground potential. The number of pad electrodes for IDT electrodes can be reduced, and further, one of the external electrodes for monitoring can be used as an external electrode for IDT electrodes connected to the ground potential, thereby reducing the number of external electrodes. Therefore, a surface acoustic wave device that can be miniaturized can be obtained.

  Furthermore, according to the surface acoustic wave device of the present invention, when the monitor pattern has a narrow part narrower than the width of the other band-like part in the middle, it is narrower than the other part of the monitor pattern. Since the corrosion of the width portion proceeds rapidly, it is possible to obtain a surface acoustic wave device in which the time required for determining the sealing state is shortened. Compared to the case where the entire width of the monitor pattern is narrow, since the length of the narrow portion is short, there is a low probability that an initial failure such as disconnection will occur at the time of manufacture. Obtainable.

  Furthermore, according to the surface acoustic wave device of the present invention, when a plurality of narrow portions are connected in parallel, sealing is performed except when all the narrow portions connected in parallel at the time of manufacture are disconnected. Since the stop state can be determined and does not become defective, a surface acoustic wave device that can be manufactured with a higher yield can be obtained.

  According to the sealing state determination method for a surface acoustic wave device of the present invention, after measuring the electrical resistance between the pair of monitor external electrodes, the monitor pattern is left in a corrosive gas or liquid, and then the pair of monitor external electrodes is corroded. Measure the electrical resistance between the external electrodes for the monitor again, and determine that the measured value of the electrical resistance after being left is higher than the measured value before being left, because the sealing state is poor, Even when resin is used as the sealing member, the sealed state can be easily determined unlike the helium leak test, and even when the sealing space is small, the sealed state can be easily determined unlike the bubble leak test. Therefore, it is possible to easily determine the sealing state of the small surface acoustic wave device.

  Hereinafter, a surface acoustic wave device and a sealing state determination method of the present invention will be described in detail with reference to the accompanying drawings.

(First example of embodiment)
FIG. 1A is an external perspective view schematically showing an example of an embodiment of a surface acoustic wave device of the present invention, and FIG. 1B is a cross-sectional view taken along line AA ′ in FIG. 2A is a plan view schematically showing the lower surface of the surface acoustic wave element constituting the surface acoustic wave device of FIG. 1, and FIG. 2B is a schematic view of the state where the protective film of FIG. 2A is removed. FIG. 3A is a plan view schematically showing the upper surface of the mounting substrate constituting the surface acoustic wave device of FIG. 1, and FIG. 3B is a mounting substrate constituting the surface acoustic wave device of FIG. It is a top view which shows typically the lower surface of this.

  In the surface acoustic wave device of this example, the IDT electrodes 21a and 21b, the IDT electrode pad electrodes 22a and 22c connected to the IDT electrode 21a, and the IDT electrode 21b connected to the IDT electrode 21b are formed on the lower surface of the piezoelectric substrate 11. Pad electrodes 22b and 22d, a monitoring pattern 23 made of a strip-shaped conductor, and a pair of monitoring pad electrodes 24a and 24b respectively connected to both ends of the monitoring pattern 23 are formed, and pad electrodes for IDT electrodes The surface acoustic wave element 10 has a protective film 31 formed by exposing the 22T, 22b, 22c, 22d, the monitor pattern 23, and the monitor pad electrodes 24a, 24b to cover the IDT electrodes 21a, 21b. . In addition, the surface acoustic wave device of this example includes an IDT electrode terminal electrode 52a, 52b, 52c, 52d corresponding to the IDT electrode pad electrode 22a, 22b, 22c, 22d, and a monitor pad electrode 24a. , 24b, and monitor terminal electrodes 54a, 54b, and monitor external electrodes 64a, 64b connected to the monitor terminal electrodes 54a, 54b. The IDT electrode pad electrodes 22a, 22b, 22c and 22d are connected to the IDT electrode terminal electrodes 52a, 52b, 52c and 52d, and the monitor pad electrodes 24a and 24b are connected to the monitor terminal electrodes 54a and 54b, respectively. The surface acoustic wave element 10 is mounted on the mounting substrate 40 by being connected by the conductor 71, and the IDT electrodes 21a and 21b and the monitor pattern 23 are hermetically sealed in the same sealing space 82 by the sealing member 81. Yes.

  The sealing space 82 is formed by being surrounded by an upper surface of the insulating substrate 41, a lower surface of the piezoelectric substrate 11, and a sealing member 81 covering the upper surface of the piezoelectric substrate 11 and the upper surface of the insulating substrate 41. In the stop space 82, IDT electrodes 21a, 21b, IDT electrode pad electrodes 22a, 22b, 22c, 22d, monitor pattern 23, monitor pad electrodes 24a, 24b, IDT electrode terminal electrodes 52a, 52b, 52c, 52d, the monitor terminal electrodes 54a and 54b, and the connection conductor 71 are hermetically sealed.

  The IDT electrodes 21a and 21b are formed side by side along the propagation direction of the surface acoustic wave, and a pair of reflector electrodes 25 are formed on both sides thereof, and the piezoelectric substrate 11, the IDT electrodes 21a and 21b, and the reflectors are formed. The electrode 25 constitutes a resonator-type surface acoustic wave filter that selectively passes a signal having a specific frequency. The reflector electrode 25 is covered with the protective film 31 and hermetically sealed in the sealing space 82 in the same manner as the IDT electrodes 21a and 21b.

  Furthermore, the monitor terminal electrodes 54a and 54b formed on the upper surface of the insulating substrate 41 and the monitor external electrodes 64a and 64b formed on the lower surface of the insulating substrate 41 are connected by the monitor wiring conductors 74a and 74b, respectively. IDT electrode terminal electrodes 52a, 52b, 52c, 52d formed on the upper surface of the insulating substrate 41 and IDT electrode external electrodes 62a, 62b, 62c, 62d formed on the lower surface of the insulating substrate 41 are IDT electrode wirings. They are connected by a conductor (not shown). In this way, both ends of the monitor pattern 23 are monitored via the monitor pad electrodes 24a and 24b, the connection conductors 71 and 71, the monitor terminal electrodes 54a and 54b, and the monitor wiring conductors 74a and 74b. The external electrodes 64a and 64b are connected. The IDT electrode 21a is connected to IDT electrode pad electrodes 22a and 22c, a connecting conductor (not shown), IDT electrode terminal electrodes 52a and 52c, and an IDT electrode wiring conductor (not shown). The external electrodes 62a and 62c for IDT electrodes are connected. Further, the IDT electrode 21b is connected via IDT electrode pad electrodes 22b and 22d, a connecting conductor (not shown), IDT electrode terminal electrodes 52b and 52d, and an IDT electrode wiring conductor (not shown). The external electrodes 62b and 62d for IDT electrodes are connected. For example, when the IDT electrode 21a is used as an input-side IDT electrode and the IDT electrode 21b is used as an output-side IDT electrode for an unbalanced input / output, an external electrical signal is input to the IDT electrode external electrode 62a. The electrical signal filtered from the IDT electrode external electrode 62b is output. At this time, the IDT electrode external electrodes 62c and 62d are connected to the ground potential.

  According to the surface acoustic wave device of this example having such a configuration, it is connected to both ends of the monitor pattern 23 made of a strip-shaped conductor hermetically sealed in the same sealing space 82 as the IDT electrodes 21a and 21b. Since the monitor external electrodes 64a and 64b are provided on the surface of the surface acoustic wave device, when the gas or liquid that corrodes the monitor pattern 23 enters the sealed space 82 when the sealing state is poor, As a result, the monitor pattern 23 corrodes and its electrical resistance increases, so that the sealed state depends on whether the electrical resistance changes between the pair of monitor external electrodes 64a and 64b connected to both ends of the monitor pattern 23. Pass / fail can be judged. As a result, even when resin is used as the sealing member, the sealing state can be easily determined unlike the helium leak test, and even when the sealing space is small, the sealing state is easily different from the bubble leak test. Therefore, it is possible to obtain a surface acoustic wave device that can be miniaturized and that can easily determine the sealed state.

  Further, the IDT electrodes 21a and 21b have a structure in which the comb teeth of a pair of comb-shaped electrodes connected to different potentials are arranged so as to be engaged with each other with a minute space therebetween. Contact, adjacent comb teeth having different potentials are connected to each other to cause an electrical short circuit. However, according to the surface acoustic wave device of this example, the monitor pattern 23 is exposed and the IDT electrode is exposed. Since the protective film 31 covered with 21a and 21b is provided, the protective film 31 prevents the occurrence of an electrical short circuit caused by the contact of the conductive foreign matter with the IDT electrodes 21a and 21b. Since the gas or liquid that corrodes the electrode can be brought into contact with the monitor pattern 23, the electrical short circuit of the IDT electrodes 21a and 21b due to the contact of the conductive foreign matter is prevented and the sealing is performed. It can condition the decision to obtain an easy surface acoustic wave device. It is not necessary that all portions of the monitor pattern 23 are exposed from the protective film 31. Similarly, all portions of the IDT electrode pad electrodes 22a, 22b, 22c, 22d and the monitor pad electrodes 24a, 24b are formed. It is not necessary to expose from the protective film 31.

  Further, the surface acoustic wave device of this example is connected to the monitor external electrodes 64a and 64b connected to both ends of the monitor pattern 23 made of a strip-like conductor hermetically sealed in the same sealing space 82 as the IDT electrodes 21a and 21b. On the surface of the surface acoustic wave device. According to the surface acoustic wave device of this example, for example, after measuring the electrical resistance between the pair of monitor external electrodes 64a and 64b, the surface acoustic wave device in a gas or liquid that corrodes the monitor pattern 23. Is left to corrode the monitor pattern 23 in the sealing space 82 of the surface acoustic wave device having a poor sealing state to increase the electrical resistance, and then the pair of monitor external electrodes 64a and 64b. By measuring the electrical resistance in between, the sealed state judgment is such that the measured value of the electrical resistance after being left is increased with respect to the measured value before being left, and the sealed state is judged to be defective The method can be used.

(Second example of embodiment)
4A is an external perspective view schematically showing another example of the embodiment of the surface acoustic wave device of the present invention, and FIG. 4B is a cross-sectional view taken along the line BB ′ in FIG. is there. 5A is a plan view schematically showing the lower surface of the surface acoustic wave element constituting the surface acoustic wave device of FIG. 4, and FIG. 5B schematically shows a state in which the protective film of FIG. 5A is removed. FIG. 6A is a plan view schematically showing the upper surface of the mounting substrate constituting the surface acoustic wave device of FIG. 4, and FIG. 6B is a mounting substrate constituting the surface acoustic wave device of FIG. It is a top view which shows typically the lower surface of this. Note that in this example, only differences from the first example described above will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  A characteristic part of the surface acoustic wave device of this example is an annular pad surrounding the IDT electrodes 21a and 21b, the IDT electrode pad electrodes 22a and 22b, the monitor pattern 23, the monitor pad electrode 24a and the reflector electrode 25. An electrode 26 is formed on the lower surface of the piezoelectric substrate 11, and an annular terminal electrode 56 surrounding the IDT electrode terminal electrodes 52a, 52b and the monitor terminal electrode 54a is formed on the upper surface of the insulating substrate 41 corresponding to the annular pad electrode 26. The annular pad electrode 26 and the annular terminal electrode 56 are connected by the annular connecting conductor 76, and a sealing space 82 surrounded by the upper surface of the insulating substrate 41, the lower surface of the piezoelectric substrate 11, and the annular connecting conductor 76 is formed. It is formed.

  The IDT electrodes 21a and 21b, the IDT electrode pad electrodes 22a and 22b, the monitor pattern 23, the monitor pad electrode 24a, the reflector electrode 25, the IDT electrode terminal electrodes 52a and 52b, and the monitor terminal electrode 54a are sealed. It is hermetically sealed in the stop space 82. That is, in the surface acoustic wave device of this example, the annular connecting conductor 76 functions as a sealing member. The configuration using the annular connecting conductor 76 as the sealing member in this way may be applied to the first example described above. Further, the sealing member 81 in the first example may be applied as the sealing member in the second example.

  Further, monitor external electrodes 64a and 64b and IDT electrode external electrodes 62a and 62b are formed on the lower surface of the insulating substrate 41. The monitor terminal electrode 54a is connected to the monitor external electrode 64a via the monitor wiring conductor 74a. The annular terminal electrode 56 is connected to the monitor external electrode 64b via the monitor wiring conductor 74b, and the IDT electrode terminal electrode 52a is connected to the IDT electrode external electrode 62a via the IDT electrode wiring conductor (not shown). The IDT electrode terminal electrode 52b is connected to an IDT electrode external electrode 62b via an IDT electrode wiring conductor (not shown).

  According to the surface acoustic wave device of this example, the annular pad electrode 26 is connected to one end of the monitor pattern 23 and simultaneously connected to the IDT electrodes 21a and 21b. Since it functions as a pad electrode for the IDT electrode at the same time as the pad electrode, the number of the pad electrodes of the surface acoustic wave element 10 can be reduced, and the surface acoustic wave element 10 can be made small. A wave device can be obtained. At this time, the annular pad electrode 26 is connected to a portion connected to the ground potential of the IDT electrodes 21a and 21b, and the annular pad electrode 26 includes the annular connection conductor 76, the annular terminal electrode 56, and the monitor wiring conductor 74b. Since the monitor pad electrode 24a and the monitor pattern 23 are connected to the IDT electrodes 21a and 21b via the annular pad electrode 26, the surface acoustic wave device is connected to the ground potential via the monitor external electrode 64b. It does not have a great influence on the electrical characteristics.

  Furthermore, according to the surface acoustic wave device of this example, the monitor external electrode 64b is connected to the monitor pattern 23 and the IDT electrodes 21a and 21b, and is connected to an external ground potential. Since it functions as an external electrode for the IDT electrode connected to the ground potential at the same time as the electrode, it is possible to reduce the number of external electrodes of the surface acoustic wave device and to obtain a more compact surface acoustic wave device. it can.

  Furthermore, according to the surface acoustic wave device of this example, the monitor pattern 23 has narrow portions 23a, 23b, and 23c that are narrower than the widths of the other band-like portions in the middle. Since the corrosion of the narrow portions 23a, 23b, and 23c proceeds faster than the other portions of 23, the time required for determining the sealed state can be shortened. Compared with the case where the entire width of the monitor pattern 23 is narrow, the surface of the surface acoustic wave device that can be manufactured with high yield because the length of the narrow portion is short and the probability of an initial failure such as disconnection during manufacturing is low. Can be obtained.

  Furthermore, according to the surface acoustic wave device of the present invention, since the plurality of narrow portions 23a, 23b, 23c are connected in parallel, all the narrow portions 23a, 23b, The surface acoustic wave device that can be manufactured with higher yield can be obtained because the sealed state can be determined and does not become defective except when a disconnection occurs at 23c.

  Although not shown in the figure, a more reliable surface acoustic wave device can be obtained by covering the upper surface and side surfaces of the piezoelectric substrate 11 with a thin resin layer for preventing the piezoelectric substrate 11 from being damaged. .

(Third example of embodiment)
FIG. 7 is a longitudinal sectional view schematically showing still another example of the embodiment of the surface acoustic wave device of the present invention. Note that in this example, only differences from the first example described above will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  Characteristic portions of the surface acoustic wave device of this example are: IDT electrodes 21a, 21b, IDT electrode pad electrodes 22a, 22b, 22c, 22d, monitor pattern 23, monitor pad electrodes 24a, 24b and reflector electrode 25. The surface acoustic wave element 10 having the protective film 31 formed on the upper surface of the piezoelectric substrate 11 is mounted in a recess 43 formed on the upper surface of the insulating substrate 41, and the upper end of the recess 43 is the sealing member 81. Thus, a sealing space 82 is formed, and the entire surface acoustic wave element 10 is hermetically sealed therein.

  Even in the surface acoustic wave device of this example having such a structure, it is easy as in the surface acoustic wave device of the first example of the embodiment and the surface acoustic wave device of the second example of the embodiment described above. The sealing state can be determined.

(Fourth example of embodiment)
Next, an example of an embodiment of a sealing state determination method for a surface acoustic wave device according to the present invention will be described using the surface acoustic wave device shown in FIGS. 1 to 7 as an example.

  The method for determining the sealing state of the surface acoustic wave device of this example is that the surface acoustic wave device is placed in a gas or liquid that corrodes the monitor pattern 23 after measuring the electrical resistance between the pair of monitor external electrodes 64a and 64b. Leave, and then measure the electrical resistance between the pair of monitor external electrodes 64a, 64b again, and seal the sealed state where the measured value of the electrical resistance after leaving is increased compared to the measured value before leaving Is determined to be defective.

  As a result, even when resin is used as the sealing member, the sealing state can be easily determined unlike the helium leak test, and even when the sealing space is small, the sealing state is easily different from the bubble leak test. Can be judged.

  In addition, the measured value of the electrical resistance before and after leaving the surface acoustic wave device in a gas or liquid that corrodes the monitor pattern is compared, and if the electrical resistance is increased, it is determined that the sealed state is defective. Compared with the case where the sealing state is judged by the change in the electrical characteristics of the surface acoustic wave device measured using, for example, a network analyzer, the surface acoustic wave can be operated by operating a complicated measuring device such as a network analyzer. Since it is not necessary to judge the quality of the sealed state from subtle changes in the waveform that represents the electrical characteristics of the device, advanced judgment by skilled workers is unnecessary, and only a simple and inexpensive measuring device such as an ohmmeter This is a method for determining the sealing state of a surface acoustic wave device that allows anyone to easily determine the sealing state.

  In the sealing state determination method of the surface acoustic wave device of this example, the electrical resistance between the monitor external electrodes 64a and 64b is measured using a resistance meter such as a milliohm meter, and the probe is connected to the monitor external electrode 64a. , 64b can be easily measured.

  Further, in the method for determining the sealing state of the surface acoustic wave device of this example, the type of gas or liquid that corrodes the monitor pattern 23 and the standing time of the surface acoustic wave device depend on the material and shape of the monitor pattern 23, etc. It can be appropriately selected depending on the situation.

  For example, a corrosive gas such as chlorine or silicon tetrachloride can be used as the gas that corrodes the monitor pattern 23. However, if a metal that has a high ionization tendency and is easily corroded is selected as the material of the monitor pattern 23, water vapor is sufficient. It can be used. When such a gas that corrodes the monitor pattern 23 is used, a gas that corrodes the monitor pattern 23 is injected into the chamber after the surface acoustic wave device is put into the chamber. At this time, if the gas that corrodes the monitor pattern 23 is pressurized after being injected, the gas that corrodes the monitor pattern 23 can be accelerated into the sealed space 82, and the time required for determining the sealing state can be reduced. can do. Also, if the pressure in the chamber is reduced before the gas that corrodes the monitor pattern 23 is injected, the gas that corrodes the monitor pattern 23 can be further infiltrated into the sealed space 82, and the sealing state can be judged. The time required can be further reduced.

  Further, as the liquid that corrodes the monitor pattern 23, for example, an alkaline solution such as an aqueous sodium hydroxide solution or an acidic solution such as hydrochloric acid can be used. After the surface acoustic wave device is immersed in such a liquid, the elastic solution is used. The liquid adhering to the surface wave device is washed away and dried. In this case as well, by selecting a metal that has a high ionization tendency and is easily corroded as the material of the monitor pattern 23, it becomes possible to use a liquid having a low degree of acidity or alkalinity, and to the other part of the surface acoustic wave device. Damage can be eliminated.

  In the surface acoustic wave device and the sealing state determination method of the surface acoustic wave device of the present invention, the piezoelectric substrate 11 is, for example, a piezoelectric material such as quartz crystal, lithium tantalate single crystal, lithium niobate single crystal, or lithium tetraborate single crystal. Made of piezoelectric single crystal or lead ceramic such as lead titanate and lead zirconate, and functions as a support for supporting various electrodes such as IDT electrodes 21a and 21b, and the piezoelectric substrate 11 via IDT electrodes 21a and 21b. When an electrical signal is applied to the, a function of generating a predetermined surface acoustic wave is provided. The thickness of the piezoelectric substrate 11 is preferably about 0.1 to 0.5 mm. If the thickness is less than 0.1 mm, the mechanical strength is insufficient and becomes brittle. If the thickness exceeds 0.5 mm, the surface acoustic wave device becomes obstructed and the material cost increases. Therefore, it is not preferable.

  When the piezoelectric substrate 11 is made of a piezoelectric single crystal, an ingot (base material) of the piezoelectric single crystal material is cut and polished so as to have a predetermined crystal direction, and strong crystals such as lithium tantalate single crystal and lithium niobate single crystal are obtained. In the case of a dielectric single crystal, a piezoelectric substrate 11 having desired piezoelectric characteristics can be obtained by performing a single domain treatment by an annealing method under an electric field.

  When the piezoelectric substrate 11 is made of piezoelectric ceramics, the raw material powder is pressed by adding a binder, or the raw material powder is mixed with water and a dispersing agent using a ball mill, dried, and then added with a binder, a solvent, a plasticizer, and the like. After forming into a sheet by a method such as molding by the doctor blade method, it is laminated and pressed as necessary, and then fired at a peak temperature of 800 ° C. to 1400 ° C. for 0.5 to 8 hours. A piezoelectric substrate 11 having desired piezoelectric characteristics can be obtained by performing a polarization treatment by applying a voltage of 3 to 6 kV / mm at a temperature of ˜200 ° C.

  Each of the IDT electrodes 21a and 21b has a pair of comb-like electrodes in which one end of a plurality of finger electrodes (electrode fingers) arranged along the propagation direction of the surface acoustic wave is connected by a bus bar electrode (common electrode). The electrode fingers of the comb-like electrodes are arranged so as to face each other so as to be alternately arranged in the propagation direction of the surface acoustic wave. When a predetermined electrical signal is applied, the surface of the piezoelectric substrate 11 has a function of generating surface acoustic waves corresponding to the arrangement pitch of the electrode fingers.

  The reflector electrode 25 is configured by connecting both ends of a plurality of reflective electrodes arranged at equal intervals at substantially the same pitch as the electrode fingers of the IDT electrodes 21a and 21b along the propagation direction of the surface acoustic wave, with a common electrode. ing. The surface acoustic wave generated in the region where the IDT electrodes 21a and 21b are formed is reflected and confined between the pair of reflector electrodes 25. The pair of reflector electrodes 25 and the IDT electrodes 21a and 21b arranged therebetween constitute a resonator type surface acoustic wave filter.

  The IDT electrode pad electrodes 22a, 22b, 22c and 22d and the monitor pad electrodes 24a and 24b are connected to the IDT electrodes 21a and 21b and the monitor pattern 23, respectively. The connecting conductor 71 that electrically connects the two is joined.

  The annular pad electrode 26 is formed in a ring shape (annular) so as to surround the IDT electrodes 21a and 21b, the IDT electrode pad electrodes 22a and 22b, the monitor pattern 23, the monitor pad electrode 24a and the reflector electrode 25. By being connected to the annular terminal electrode 56 by the annular connecting conductor 76, the IDT electrode 21a, the IDT electrode 21a, and the function of forming a sealing space 91 between the lower surface of the piezoelectric substrate 11 and the upper surface of the insulating substrate 41 are provided. 21b and the monitor pattern 23 are electrically connected to the annular connecting conductor 76.

  The electrodes formed on the piezoelectric substrate 11 such as the IDT electrodes 21a and 21b, the IDT electrode pad electrodes 22a, 22b, 22c and 22d, the monitor pad electrodes 24a and 24b, the annular pad electrode 26 and the reflector electrode 25 are as follows. For example, it is made of a metal material such as Al or an alloy containing Al as a main component. For example, a resist is spin-coated on an electrode film formed on the surface of the piezoelectric substrate 11 by vapor deposition or sputtering, and exposure is performed using a stepper device or the like. -After development, it is formed by etching using a RIE (Reactive Ion Etching) apparatus or the like. The thicknesses of the IDT electrodes 21a and 21b and the reflector electrode 25 are, for example, about 0.1 to 1 μm, and are determined according to the piezoelectric substrate to be used, desired frequency characteristics and temperature characteristics. The IDT electrode pad electrodes 22a, 22b, 22c, 22d, the monitor pad electrodes 24a, 24b, and the annular pad electrode 26 are covered with Cr, Ni, Au or the like in order to improve solderability. It is desirable to coat the surface with Au in order to improve the corrosion resistance. It is desirable that the thickness is thicker than other electrodes.

  The monitor pattern 23 is hermetically sealed in the same sealed space 82 as the IDT electrodes 21a and 21b, and corrodes the monitor pattern 23 that has entered the sealed space 82 of the surface acoustic wave device having a poor sealing state. It has the function of indicating that the sealing state of the surface acoustic wave device is defective by corroding with gas or liquid and increasing the electrical resistance. Therefore, it is desirable that the monitor pattern 23 has a material and a shape that easily corrode.

  As the material of the monitor pattern 23, a metal having a high ionization tendency is desirable. In particular, a metal whose Gibbs free energy change due to oxidation is negative is prone to oxidation reaction and is easily corroded. This is desirable because it can reduce the time required for the process. Further, it is desirable that the metal has a higher ionization tendency than the material of the surfaces of the IDT electrode external electrodes 62a, 62b, 62c, 62d and the monitor external electrodes 64a, 64b. The material of the monitor pattern 23 is corroded but the surface material of the IDT electrode external electrodes 62a, 62b, 62c, 62d and the monitor external electrodes 64a, 64b is selected so as not to corrode, whereby the IDT electrode external electrode 62a is selected. 62b, 62c, 62d and the external electrodes for monitoring 64a, 64b can be determined without damaging the surface acoustic wave device. It is often used as a material for the IDT electrodes 21a and 21b and the reflector electrode 25, and is monitored by an alloy such as Al-Cu, Al-Si, Al-Si-Cu, etc., which has a high ionization tendency and is easily corroded. If the pattern 23 is formed, water vapor can be used as a gas that corrodes the monitor pattern 23. Therefore, the surface acoustic wave device can be easily sealed using simple equipment without damaging the surface acoustic wave device. Can be judged.

  As the shape of the monitor pattern 23, it is desirable that the thickness is thin and the width is narrow from the viewpoint of allowing corrosion to proceed in a short time. However, if the width is narrow as a whole, disconnection defects are likely to occur during manufacturing. In particular, it is desirable to have a shape having narrow portions 23a, 23b, and 23c. The narrow width portions 23a, 23b, and 23c are, for example, 0.05 μm to 0.2 μm in thickness, 0.5 μm to 2 μm in width, and 50 μm to 200 μm in length. When the monitor pattern 23 is formed with the same material and thickness as the IDT electrodes 21a and 21b and the reflector electrode 25, the monitor pattern 23 can be formed simultaneously with the IDT electrodes 21a and 21b and the reflector electrode 25. Therefore, a surface acoustic wave device that can be manufactured by a simple process can be obtained.

The protective film 31 has a function of preventing the occurrence of an electrical short circuit due to adhesion of metallic foreign matter or the like to the IDT electrodes 21a and 21b. For example, an insulating or semiconductive material such as SiO ₂ or SiN is used. It can be used suitably, The thickness shall be about 0.01 micrometer-0.05 micrometer, for example. For example, a film can be formed by using a CVD (Chemical Vapor Deposition) apparatus or the like and then patterned by using a photolithography technique.

  The insulating substrate 41 is, for example, a single-layer or multi-layer substrate made of a ceramic material such as glass-ceramics or alumina, or a resin material such as an epoxy resin, and protects the piezoelectric substrate 11 in addition to the function of forming the sealing space 82. Has the function of The thickness of the insulating substrate 41 is preferably about 0.1 to 0.5 mm. If the thickness is less than 0.1 mm, the mechanical strength is insufficient and the function of protecting the piezoelectric substrate 11 is deteriorated. If the thickness exceeds 0.5 mm, the surface acoustic wave device is thinned. This is not preferable because the material cost increases.

  When the insulating substrate 41 is made of a ceramic material, for example, a method in which a binder is added to the raw material powder and pressed, or the raw material powder is mixed with water and a dispersant using a ball mill and then dried, and the binder, solvent, plasticizer, etc. Is formed into a sheet by a method such as molding by the doctor blade method, etc., and is laminated and pressed as necessary, and then fired at a peak temperature of 800 ° C. to 1400 ° C. for 0.5 to 8 hours.

  The IDT electrode terminal electrodes 52a, 52b, 52c, and 52d and the monitor terminal electrodes 54a and 54b are portions to which a connection conductor 71 that electrically connects the surface acoustic wave element 10 and the mounting base 40 is joined. The IDT electrode external conductors 62a, 62b, 62c, 62d and the monitor external electrodes 64a, 64b are connected by an IDT electrode interconnect conductor (not shown) and monitor interconnect conductors 74a, 74b.

  The annular terminal electrode 56 is formed in a ring shape so as to surround the IDT electrode terminal electrodes 52a and 52b and the monitor terminal electrode 54a, and is bonded to the annular pad electrode 26 by the annular connecting conductor 76, thereby The sealing space 82 is formed between the lower surface of the substrate 11 and the upper surface of the insulating substrate 41.

  The IDT electrode external electrodes 62a, 62b, 62c, and 62d and the monitor external electrodes 64a and 64b are formed on the lower surface of the insulating substrate 41, and are electrically joined by mechanically joining the surface acoustic wave device to a mounting substrate or the like. Has a function to connect. The IDT electrode terminal conductors 52a, 52b, 52c, 52d, the monitor terminal electrodes 54a, 54b, or the annular terminal electrode 56 are connected to each other by an IDT electrode wiring conductor (not shown) and monitor wiring conductors 74a, 74b. Yes.

  The IDT electrode terminal electrodes 52a, 52b, 52c, and 52d, the monitor terminal electrodes 54a and 54b, the annular terminal electrode 56, the IDT electrode external electrodes 62a, 62b, 62c, and 62d formed on the insulating substrate 41 and The monitor external electrodes 64a and 64b are made of a highly conductive metal film such as Ag or Cu. For example, a conductive paste made of Ag or Cu is applied by using a conventionally known screen printing method or roller transfer. It can be formed by firing at about 500 to 900 ° C. Furthermore, when a metal film having high bonding property with solder such as Ni, Sn, Au or the like is formed on the surface by plating or the like, the bonding property with the solder can be improved. Further, from the viewpoint of improving corrosion resistance, it is desirable that the surface be an Au layer.

  The IDT electrode wiring conductor (not shown) and the monitor wiring conductors 74a and 74b are formed on the upper surface of the insulating substrate 41. The IDT electrode terminal electrodes 52a, 52b, 52c and 52d, the monitor terminal electrodes 54a and 54b, and The annular terminal electrode 56 has a function of electrically connecting the IDT electrode external electrodes 62a, 62b, 62c, 62d and the monitor external electrodes 64a, 64b formed on the lower surface of the insulating substrate 41. It is formed by filling a hole formed in the substrate 41 with a drill, a laser, or the like with a conductive paste such as Ag or Cu and baking it at about 500 to 900 ° C.

  The connection conductor 71 electrically connects the IDT electrode pad electrodes 22a, 22b, 22c and 22d, the monitor pad electrodes 24a and 24b, the IDT electrode terminal electrodes 52a, 52b, 52c and 52d, and the monitor terminal electrodes 54a and 54b. Has a function to connect. In the case of the surface acoustic wave device of the first example of the embodiment and the surface acoustic wave device of the second example of the embodiment, the material of the connecting conductor 71 is, for example, a metal bump made of Au or solder. In the case of the surface acoustic wave device of the third example of the above-described embodiment, a fine metal wire such as Au or Al is preferably used.

  The annular connecting conductor 76 electrically connects the annular pad electrode 26 and the annular terminal electrode 56, and at the same time has a function of forming a sealing space 82 between the lower surface of the piezoelectric substrate 11 and the upper surface of the insulating substrate 41. In the surface acoustic wave device of the second example of the embodiment, it also functions as a sealing member. As a material of the annular connecting conductor 76, for example, solder can be preferably used. From the viewpoint of preventing remelting when performing a reflow process for mounting a surface acoustic wave device on a mounting substrate or the like, a high melting point solder is desirable.

  In the surface acoustic wave device according to the first example of the embodiment described above, the sealing member 81 has a function of covering the upper surface of the piezoelectric substrate 11 and the upper surface of the insulating substrate 41 to form a sealing space 82. A thermosetting resin such as an epoxy resin or a polyimide resin is preferably used, and its thickness is, for example, about 50 μm to 500 μm. For example, when a thermosetting resin is used, such a sealing member 81 is mounted on the monitor pad electrodes 24a and 24b and the IDT electrode pad electrodes 22a, 22b, 22c, and 22d of the surface acoustic wave element 10, and mounted. After connecting the monitor terminal electrodes 54a and 54b and the IDT electrode terminal electrodes 52a, 52b, 52c and 52d with the connection conductor 71, a liquid thermosetting resin is applied using a vacuum printer or the like. It can be formed by putting it in a high-temperature tank or the like and heating it to cure.

  In the third example of the above-described embodiment, the sealing member 81 has a function of covering the opening on the upper surface of the insulating substrate 41 to form a sealing space 82. For example, Fe-Ni-Co or the like A metal made of an alloy is preferably used, and its thickness is, for example, 10 μm to 100 μm. Further, the surface may be plated with Ni or Au as necessary, and bonded to the upper surface of the mounting substrate 40 by, for example, a method such as seam welding.

(Modification)
The present invention is not limited to the first to fourth examples of the embodiment described above, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, in the above-described embodiment, an example in which a resonator-type surface acoustic wave filter is configured by the piezoelectric substrate 11, the IDT electrodes 21a and 21b, and the reflector electrode 25 is shown as the surface acoustic wave device. However, a transversal surface acoustic wave filter having no reflector electrode 25, a one-terminal pair surface acoustic wave resonator having only one IDT electrode, and a ladder-type surface acoustic wave filter using the same Needless to say, the present invention is effective in other surface acoustic wave devices.

  Next, specific examples of the surface acoustic wave device and the sealing state determination method of the surface acoustic wave device according to the present invention will be described by taking the surface acoustic wave device of the second example of the embodiment shown in FIGS. 4 to 6 as an example. .

First, lithium tantalate (LiTaO ₃ ) was used as a piezoelectric mother substrate to be divided into piezoelectric substrates 11, and an Al—Cu (Al: 99%) thin film having a thickness of 0.1 μm was formed on the main surface.

  Next, a photoresist was applied to a thickness of about 0.5 μm using a resist coating apparatus.

  Next, the photoresist is exposed using a reduction projection exposure apparatus (stepper), and unnecessary portions of the photoresist are dissolved with an alkaline developer using a developing apparatus, so that the IDT electrode in the surface acoustic wave device 10 shown in FIG. Resist patterns having the same shape as 21a, 21b, IDT electrode pad electrodes 22a, 22b, monitor pattern 23, monitor pad electrode 24a, reflector electrode 25 and annular pad electrode 26 were formed.

  Next, the Ti / Al—Cu laminated film in the resist non-formation portion is etched using an RIE apparatus, whereby the IDT electrodes 21a and 21b and the IDT electrode pad electrodes 22a and 22b in the surface acoustic wave device 10 shown in FIG. The electrode pattern was formed so as to become the monitor pattern 23, the monitor pad electrode 24a, the reflector electrode 25, and the annular pad electrode 26, and then the resist on the electrode pattern was removed.

Next, a SiO ₂ film serving as a protective film was formed to a thickness of about 0.02 μm on the electrode pattern and the main surface of the piezoelectric mother substrate using a CVD apparatus.

Next, a photoresist is applied on the SiO ₂ film, exposed and developed to form a resist pattern that opens on the IDT electrode pad electrodes 22a, 22b, the monitor pad electrode 24a, and the annular pad electrode 26; The SiO ₂ film located on the IDT electrode pad electrodes 22a and 22b, the monitor pad electrode 24a and the annular pad electrode 26 was removed by etching using an RIE apparatus.

  Next, Cr, Ni, and Au films were formed in this order on the entire surface using a sputtering apparatus, and the total electrode film thickness was about 1 μm.

  Next, the resist and the conductor film made of Cr, Ni, and Au formed on the resist are simultaneously removed by the lift-off method, and the IDT electrode pad electrodes 22a, 22b, 22c, 22d, the monitor pad electrodes 24a, 24b, and the ring The pad electrode 26 was completed.

Next, a photoresist is applied on the SiO ₂ film, exposed and developed to form a resist pattern that opens on the monitor pattern 23, and SiO ₂ positioned on the monitor pattern 23 using an RIE apparatus. The film was etched away.

  Next, the piezoelectric mother substrate was diced using a dicing saw and divided into each surface acoustic wave element chip to obtain a plurality of surface acoustic wave elements 10.

  Next, IDT electrode terminal electrodes 52a and 52b, a monitor terminal electrode 54a and an annular terminal electrode 56 are formed on the upper surface, and the IDT electrode external electrodes 62a and 62b and the monitor are formed on the lower surface. External ceramic electrodes 64a and 64b were formed, and a ceramic substrate on which IDT electrode wiring conductors (not shown) and monitoring wiring conductors 74a and 74b were respectively formed was prepared. The ceramic substrate was a low-temperature fired substrate made of glass ceramics.

  Next, solder was applied to the IDT electrode terminal electrodes 52a and 52b, the monitor terminal electrode 54a and the annular terminal electrode 56 on the upper surface of the ceramic substrate by a screen printing method, and then heated and melted to form solder bumps. Note that Sn—Pb solder was used as the solder.

  Next, a plurality of surface acoustic wave elements 10 produced by the above process using a flip chip mounting apparatus were placed on the ceramic substrate with the electrode formation surface down, and heated to such an extent that the solder bumps did not melt. The surface acoustic wave element 10 is subjected to pressure and ultrasonic vibration from above to ultrasonically weld the IDT electrode pad electrodes 22a and 22b, the monitor pad electrode 24a and the annular pad electrode 26, and the solder bumps. Fixed.

Next, the plurality of surface acoustic wave elements 10 and the ceramic substrate are placed by placing the ceramic substrate on which the plurality of surface acoustic wave elements 10 are temporarily fixed in the chamber and heating in a N ₂ atmosphere to melt the solder bumps. And joined. As a result, the IDT electrode pad electrodes 22a and 22b, the monitor pad electrodes 24a and 24b, the IDT electrode terminal electrodes 52a and 52b, and the monitor terminal electrodes 54a and 54b are electrically connected by the connection conductor 71 and are annular. The pad electrode 26 and the annular terminal electrode 56 are joined by the annular connecting conductor 76 to form a sealing space 82 between the surface acoustic wave element 10 and the ceramic substrate.

  Next, the ceramic substrate to which the plurality of surface acoustic wave elements 10 were bonded was diced using a dicing saw and divided into individual pieces to obtain a plurality of surface acoustic wave devices. The thickness of the monitor pattern 23 was 0.1 μm, the widths of the narrow portions 23a, 23b, and 23c were 0.1 μm, and the length was 100 μm.

  Next, the probe is applied to the monitor external electrodes 64a and 64b of the surface acoustic wave device of the present invention manufactured as described above, and the electricity between the monitor external electrodes 64a and 64b is measured using a HIoki milliohm meter (model 3227). Resistance was measured.

  Next, the surface acoustic wave device was put into a saturation type super accelerated life test device PC-242 manufactured by Hirayama Seisakusho, and left in a saturated water vapor atmosphere of 2 atm at 121 ° C. for 1 hour.

  Next, the probe is applied to the monitor external electrodes 64a and 64b of the surface acoustic wave element taken out from the saturation type super acceleration life test apparatus PC-242 made by Hirayama Seisakusho, and a milliohm meter (model 3227) made by HIOKI is used. The electrical resistance between the monitor external electrodes 64a and 64b was measured again, and the case where the electrical resistance increased was determined to be defective.

  Next, when the surface acoustic wave device judged to be in a poor sealing state was disassembled, it was confirmed that the monitor pattern 23 was corroded. This confirmed the effectiveness of the present invention.

(A) is an external appearance perspective view which shows typically an example of embodiment of the surface acoustic wave apparatus of this invention, (b) is the sectional view on the A-A 'line in (a). (A) is a top view which shows typically the lower surface of the surface acoustic wave element which comprises the surface acoustic wave apparatus of FIG. 1, (b) is a plane which shows the state which removed the protective film of (a) typically FIG. FIG. 2A is a plan view schematically showing an upper surface of a mounting substrate constituting the surface acoustic wave device of FIG. 1, and FIG. 2B is a schematic view of a lower surface of the mounting substrate constituting the surface acoustic wave device of FIG. FIG. (A) is an external appearance perspective view which shows typically the other example of embodiment of the surface acoustic wave apparatus of this invention, (b) is the B-B 'sectional view taken on the line in (a). (A) is a top view which shows typically the lower surface of the surface acoustic wave element which comprises the surface acoustic wave apparatus of FIG. 4, (b) is a plane which shows the state which removed the protective film of (a) typically FIG. 5A is a plan view schematically showing an upper surface of a mounting substrate constituting the surface acoustic wave device of FIG. 4, and FIG. 5B is a schematic view of a lower surface of the mounting substrate constituting the surface acoustic wave device of FIG. FIG. It is a longitudinal section showing still another example of an embodiment of a surface acoustic wave device of the present invention typically.

Explanation of symbols

10: Surface acoustic wave device
11: Piezoelectric substrate
21: IDT electrode
22a, 22b, 22c, 22d: pad electrodes for IDT electrodes
23: Monitor pattern
23a, 23b, 23c: Narrow width part of monitor pattern
24a, 24b: Pad electrode for monitoring
40: Substrate for mounting
41: Insulating substrate
52a, 52b, 52c, 52d: IDT electrode terminal electrodes
54a, 54b: Monitor terminal electrode
64a, 64b: Monitor external electrode
81: Sealing member
82: Sealing space

Claims (6)

  An IDT electrode on one main surface of the piezoelectric substrate, an IDT electrode pad electrode connected to the IDT electrode, a monitoring pattern made of a strip-shaped conductor, and a pair of monitoring pad electrodes connected to both ends of the monitoring pattern, respectively And a surface acoustic wave element in which a protective film covering the IDT electrode is formed by exposing the IDT electrode pad electrode, the monitoring pattern, and the monitoring pad electrode, and the IDT electrode is formed on the insulating substrate. A mounting substrate on which an IDT electrode terminal electrode corresponding to the electrode pad electrode, a monitoring terminal electrode corresponding to the monitoring pad electrode, and a monitoring external electrode connected to the monitoring terminal electrode are formed; The IDT electrode pad electrode and the IDT electrode terminal electrode, and the monitor pad electrode and the monitor The surface acoustic wave device is characterized in that each of the IDT electrodes and the monitor pattern are hermetically sealed in the same sealing space by a sealing member while being mounted by connecting each of the child electrodes with a connecting conductor. .   2. The surface acoustic wave device according to claim 1, wherein the monitor pattern is formed of the same material and the same thickness as the IDT electrode.   One of the pair of monitor external electrodes is connected to a ground potential, and the monitor pad electrode connected to the monitor external electrode is connected to a portion connected to the ground potential of the IDT electrode. The surface acoustic wave device according to claim 1.   2. The surface acoustic wave device according to claim 1, wherein the monitor pattern has a narrow portion narrower than the width of the other band-shaped portion in the middle.   The surface acoustic wave device according to claim 4, wherein the plurality of narrow portions are connected in parallel.   2. The surface acoustic wave device according to claim 1, after measuring the electrical resistance between the pair of external electrodes for monitoring, left in a gas or liquid that corrodes the monitoring pattern, and thereafter, for the pair of monitoring electrodes. Elasticity measured by measuring the electrical resistance between the external electrodes again, and determining that the sealed state is defective if the measured value of the electrical resistance after being left is increased with respect to the measured value before being left Method for determining sealing state of surface wave device.

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