JP2008270594A - Electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device whose characteristics hardly change after mounting on a mounting substrate.
An electronic component 2 having a plurality of terminal electrodes 2b and an annular conductor 2c formed on a lower surface thereof is mounted on a mounting substrate 1 having a terminal electrode pad 1b and an annular conductor pad 1c formed on an upper surface thereof. 2b and terminal electrode pad 1b are connected and mounted via brazing material 4 and annular conductor 2c and annular conductor pad 1c via annular brazing material 3, respectively, and cover the outer surface of annular brazing material 3. Thus, the electronic device 10 is formed with the plating film 6 having a melting point higher than that of the annular brazing material 3 and with the resin 5 buried between the electronic component 2 and the mounting substrate 1 outside the plating film 6. Since the plated film 6 is not remelted and maintains hardness and acts as a wall against pressure from the outside, the remelted annular brazing material 3 is difficult to be pushed inward, and the characteristics of the electronic device 2 after mounting are improved. Fluctuation can be suppressed.
[Selection] Figure 2

Description

  The present invention relates to an electronic device such as a surface acoustic wave device having a small size and excellent characteristic stability after mounting.

  2. Description of the Related Art Conventionally, electronic devices using surface acoustic wave elements have been widely used as electronic devices used in electronic devices such as communication devices. A surface acoustic wave is a vibration wave obtained by an IDT (Inter Digital Transducer) electrode formed on one main surface of a piezoelectric substrate. Since a surface acoustic wave element has a high Q value, it is used for a resonator, filter, duplexer, etc. Has been. An electronic device using a surface acoustic wave element has a structure in which a space is secured in the vicinity of the IDT electrode and the space is sealed in order not to inhibit vibrations generated in the vicinity of the IDT electrode of the surface acoustic wave element. There is a need.

  As an example of an electronic device using a surface acoustic wave element, for example, an electronic component as a surface acoustic wave element in which an IDT electrode, a plurality of terminal electrodes, and an annular conductor surrounding the plurality of terminal electrodes are formed on the bottom surface On the mounting substrate on which the terminal electrode pad corresponding to the terminal electrode and the annular conductor pad corresponding to the annular conductor are formed, the terminal electrode and the terminal electrode pad are interposed between the annular conductor and the annular conductor pad via the brazing material. 2. Description of the Related Art There is known an electronic device having a configuration in which a resin is buried between an electronic component and a mounting substrate on the outer side of an annular brazing material, each connected via an annular brazing material (see, for example, Patent Document 1). . For the brazing material and the annular brazing material, the same material can be used. For example, solder is preferably used. The resin buried between the electronic component and the mounting substrate is made of a resin material having high strength and insulation, such as an epoxy resin.

  According to the example of the electronic device described above, the space near the IDT electrode is surrounded by the gap between the electronic component and the mounting substrate, the annular conductor, the annular conductor pad, and the brazing material connecting the annular conductor and the annular conductor pad. It has a sealed configuration. In the example of the electronic component described above, the plurality of terminal electrodes formed near the IDT electrode are also sealed in the same space as the IDT electrode for the purpose of preventing oxidation.

  In addition, the resin buried between the electronic component and the mounting board in the above-described electronic device is used for mounting the electronic device on a circuit board such as a mother board using the mounting solder. When the brazing material and the annular brazing material of the electronic device are remelted and softened by heating, the electronic component falls as a result of its own weight and serves as a support for preventing the distance between the electronic component and the mounting board from becoming shorter. It has a function.

The electronic device described above has a mounting external terminal formed on the lower surface or side surface, and the external terminal is connected to a circuit pattern on a circuit board such as a mother board through the mounting solder. Yes.
Japanese Patent Laid-Open No. 2007-6110

  However, such an electronic device has conventionally had a problem that its characteristics are likely to fluctuate when mounted on a circuit board.

  For example, in the example of the electronic device described above, in the process of mounting the electronic device on the circuit board, when the electronic device is heated, the re-melted annular brazing material is pushed inside the annular conductor and the annular conductor pad. There is a problem that the terminal electrode, the terminal electrode pad, or the brazing material connecting them may come into contact with the terminal electrode, the terminal electrode pad, and the characteristics of the electronic device.

  One of the causes of the remelted annular brazing material being pushed inward can be the effect of moisture and gas remaining on the resin buried between the electronic component and the mounting substrate in the process of manufacturing the electronic device. . That is, in the process of mounting the electronic device on the circuit board, when the electronic device is heated, the brazing material and the annular brazing material of the electronic device are remelted and softened as described above. Since the moisture and gas remaining in the resin are also heated and rapidly expanded, the annular brazing material is pushed out from the outside to the inside of the annular conductor and the annular conductor pad.

  The present invention has been devised in view of such problems in the conventional electronic component mounting structure, and an object of the present invention is to provide an electronic device whose characteristics are unlikely to vary when mounted on a mounting board. It is in.

  In the electronic device according to the present invention, an electronic component in which a plurality of terminal electrodes and an annular conductor surrounding the plurality of terminal electrodes are formed on a lower surface corresponds to a terminal electrode pad corresponding to the terminal electrode and the annular conductor on an upper surface. On the mounting substrate on which the annular conductor pad is formed, the terminal electrode and the terminal electrode pad are connected via a brazing material, and the annular conductor and the annular conductor pad are connected via an annular brazing material, respectively. A plating film having a melting point higher than that of the annular brazing material is formed so as to cover the outer surface of the annular brazing material, and between the electronic component and the mounting substrate outside the plating film. The resin is buried.

  In the electronic device according to the aspect of the invention, in the configuration described above, the plating film may include at least a part of the outer periphery of the annular conductor on the annular brazing material side and a part of the outer periphery of the annular conductor pad on the annular brazing material side. It is also characterized by being formed so as to cover.

  According to the electronic device of the present invention, in the step of mounting the electronic device on the mounting substrate, the annular brazing material connecting the annular conductor and the annular conductor pad is remelted and softened, and the electronic component and the mounting substrate Even if it tries to push the annular brazing material from the outside to the inside of the annular conductor and the annular conductor pad by heating and suddenly expanding the moisture and gas remaining in the resin buried in between, the inside of the resin, Since a plating film having a melting point higher than that of the annular brazing material is formed so as to cover the outer surface of the annular brazing material, the plating film is not remelted and maintains hardness without being subjected to pressure from the outside. It plays the role of a wall, and it becomes difficult for the remelted annular brazing material to be pushed out of the annular conductor and the annular conductor pad to flow out, and the terminal electrode, the terminal electrode pad, or the brazing material connecting them. Since the occurrence of contact is reduced, the characteristics of the electronic device after mounting can be reduced disadvantageously varies.

  According to the electronic device of the present invention, the plating film is formed so as to cover at least a part of the outer periphery of the annular conductor on the annular brazing material side and at least a part of the outer periphery of the annular conductor pad on the annular brazing material side. When the annular brazing material is remelted and softened, the plating film is fixed at least on the annular brazing material side of the outer periphery of the annular conductor and at least on the annular brazing material side of the outer periphery of the annular conductor pad. As a result, the plating film serving as a wall becomes difficult to move, and the remelted annular brazing material is more unlikely to flow out by being pushed inside the annular conductor and the annular conductor pad.

  Hereinafter, an electronic device of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an external perspective view showing an example of an embodiment of an electronic device according to the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A 'of FIG. In the electronic device 10 shown in these drawings, as a basic configuration, an electronic component 2 is mounted on a mounting substrate 1 via a brazing material 4 and an annular brazing material 3, and the mounting substrate 1 and the electronic component 2 are mounted. The resin 5 is buried in the vicinity of the four corners.

  FIG. 3 is an external perspective view of the electronic component 2 as viewed from below. The electronic component 2 in this example is a surface acoustic wave element, and a conductor pattern such as an IDT electrode 2d, a pair of reflector electrodes 2e, a plurality of terminal electrodes 2b, and an annular conductor 2c surrounding them is formed on the lower surface of the piezoelectric substrate 2a. Is formed.

  The piezoelectric substrate 2a is a rectangular flat plate having a thickness of 0.1 to 0.5 m. As a material, for example, a piezoelectric material such as quartz, lithium tantalate single crystal, lithium niobate single crystal, lithium tetraborate single crystal, etc. A single crystal is used. The conductor pattern is a conductor film having a thickness of about 0.1 to 1 μm, and as a material, for example, a metal material such as aluminum or an alloy containing aluminum as a main component is used.

  The above electronic component 2 can be manufactured by the following methods, for example.

  First, an ingot (base material) of a piezoelectric single crystal material is cut and polished so as to have a predetermined crystal direction, and in the case of a ferroelectric single crystal such as a lithium tantalate single crystal and a lithium niobate single crystal, a slow cooling method under an electric field By performing the single domain processing by, for example, a piezoelectric mother substrate having desired piezoelectric characteristics can be manufactured. Next, a conductor film such as aluminum is formed on the main surface of the piezoelectric mother substrate by, for example, vapor deposition or sputtering, and a resist is formed on the electrode film by spin coating or the like, and a portion corresponding to the conductor pattern is shielded from light. The resist film is exposed and developed using a stepper device after overlaying the patterned film, and then the conductive film is etched using a RIE (Reactive Ion Etching) device and the resist is removed. A conductor pattern can be formed. In addition, the rectangular electronic component 2 used in the electronic device 10 of the present invention is formed so that a plurality of conductor pattern groups are arranged vertically and horizontally on the main surface of the piezoelectric mother substrate. It can be manufactured by cutting and dividing into individual piezoelectric substrates 2a with a dicing saw.

  In the electronic component 2 described above, the IDT electrode 2d includes a pair of comb-like electrodes formed by connecting one end of a plurality of electrode fingers arranged along the propagation direction of the surface acoustic wave with a common electrode. The electrode fingers of the electrode-like electrode are arranged 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 to the IDT electrode 2d, the piezoelectric electrode It has a function of generating surface acoustic waves corresponding to the arrangement pitch of the electrode fingers on the surface of the substrate 2a. The reflector electrode 2e has a configuration in which both ends of a plurality of reflective electrodes arranged at equal intervals at substantially the same pitch as the electrode fingers of the IDT electrode 2d are connected by a common electrode along the propagation direction of the surface acoustic wave. The surface acoustic wave generated in the region where the IDT electrode 2d is formed is reflected and confined between the pair of reflector electrodes 2e. The plurality of terminal electrodes 2b are connected to an external circuit to input / output electric signals with the IDT electrode 2d. The role of the annular conductor 2c will be described later.

  FIG. 4 is an external perspective view of the mounting substrate 1 as viewed from above. In this example, the mounting substrate 1 has conductor pads such as a terminal electrode pad 1b corresponding to the terminal electrode 2b and an annular conductor pad 1c corresponding to the annular conductor 2c formed on the upper surface of the insulating substrate 1a and mounted on the lower surface. The external terminal 1d is formed.

  The insulating substrate 1a is a rectangular single-layer circuit board or a multilayer circuit board having a thickness of 0.1 to 0.5 mm. As the material, for example, a ceramic material such as glass ceramic or alumina ceramic, or a resin material such as epoxy resin is used. It is done. In the case of using a ceramic material as the material of the insulating substrate 1a, 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 dried, and then the binder, solvent, plastic By adding a chemical agent etc. and forming it into a sheet by the method of molding by the doctor blade method, etc., after laminating and pressing it as necessary, by baking at a peak temperature of 800 ° C. to 1400 ° C. for about 0.5 to 8 hours Can be produced.

  The terminal electrode pad 1b, the annular conductor pad 1c, and the external terminal 1d are conductor films having a thickness of 5 to 15 μm, and as the material, for example, a highly conductive metal material such as silver or copper is used. For the terminal electrode pad 1b, the annular conductor pad 1c and the external terminal 1d, for example, a conductive paste made of silver, copper or the like is applied by using a conventionally known screen printing method or roller transfer, and baked at about 500 to 900 ° C. Can be formed. Furthermore, when a metal film having high bondability with solder such as nickel, tin, and gold is formed on the surface by plating or the like, the bondability with solder can be improved.

  When the electronic component 2 is mounted on the mounting substrate 1, the terminal electrode 2b and the terminal electrode pad 1b are connected via the brazing material 4, and the annular conductor 2c and the annular conductor pad 1c are connected via the annular brazing material 3, respectively. It is done by doing. As the brazing material 4 and the annular brazing material 3, for example, a tin-antimony or tin-silver solder material containing 90% or more of tin is used.

When the brazing material 4 and the annular brazing material 3 are made of the same solder material, for example, a solder paste is applied on the mounting substrate 1 by screen printing or the like so as to cover the terminal electrode pad 1b and the annular conductor pad 1c, Solder bumps are formed by heating and melting, and the electronic component 2 is mounted on the mounting substrate 1 so that the terminal electrode pads 1b and the terminal electrodes 2b correspond to the annular conductor pads 1c and the annular conductors 2c, respectively. It is placed on top and heated to such an extent that the solder bumps do not melt, and pressure and ultrasonic vibration are applied to the electronic component 2 from above to ultrasonically bond the terminal electrode 2b and the annular conductor 2c and the solder bumps, and temporarily fix them. It is possible to form the brazing material 4 and the annular brazing material 3 by putting them into the chamber and heating them in an N ₂ atmosphere to remelt the solder bumps and then solidifying them. . In this process, a process substrate is prepared by preparing a collective board in which a plurality of mounting boards 1a are arranged in a vertical and horizontal manner, and mounting a plurality of electronic components 2 on the collective board. Reasonably shortened.

  In the electronic device 10 of the present invention, the annular conductor 2c, the annular conductor pad 1c, and the annular conductor in the space 7 between the electronic component 2 and the mounting substrate 1 are disposed in the space 7 near the IDT electrode 2d and the pair of reflector electrodes 2e. 2c and the annular conductor pad 1c are sealed by surrounding them with an annular brazing material 3. This prevents foreign matter from entering the space 7 from the outside and prevents the vibration from being hindered. Similarly, the plurality of terminal electrodes 2b formed on the lower surface of the electronic component 2 are sealed in the same space 7 as the IDT electrode 2d for the purpose of preventing oxidation.

  In the electronic device 10 of the present invention, the plating film 6 is formed so as to cover the outer surface of the annular brazing material 3, and between the electronic component 2 and the mounting substrate 1 outside the plating film 6. The resin 5 is embedded in the surface. FIG. 5 shows an enlarged view of the main part Z of FIG.

  The plating film 6 is a conductor film having a thickness of 0.5 to 4 μm, for example, and a metal material having a melting point higher than that of the annular brazing material 3, such as nickel, is used as the material. As the resin 5, for example, a thermosetting resin such as an epoxy resin or a polyimide resin excellent in heat resistance is used.

  The plating film 6 is formed by preparing a mounted aggregate substrate on which the electronic components 2 are mounted on the above-described aggregate substrate, and immersing them entirely in a nickel plating solution and performing an electroless plating process. Can do.

  Then, on the outer side of the plating film 6 formed by the above method, an uncured epoxy resin is applied between the upper surface of the mounted assembly board and the electronic component 2, and is left to cure in the high temperature bath. The electronic device 10 of the present invention can be manufactured by cutting between adjacent electronic components 2 of the mounted aggregate substrate using a dicing saw. The electronic device 10 in this example uses a dicing saw having a certain cutting width when cutting the mounted aggregate substrate, and uses a part of the outside of the electronic component 2 and the outside of the annular brazing material 3. By simultaneously cutting the portions, a part of the outer side of the annular brazing material 3 is exposed so as to be flush with the side surface of the mounting substrate 1 and the side surface of the electronic component 2, and as shown in FIGS. The resin 5 is formed at the four corners between the mounting substrate 1 and the electronic component 2 outside the corners of the circular conductor 2c and the circular conductor pad 1c having a pattern shape with rounded corners.

  The resin 5 formed by the above method has a function as a support for supporting the electronic component 2 on the mounting substrate 1. For example, in the process of mounting the electronic device 10 on a circuit board such as a mother board using mounting solder, when the mounting solder is heated, the brazing material 4 and the annular brazing material 3 of the electronic device 10 are remelted. In order to prevent the electronic component 2 from descending and the distance between the electronic component 2 and the mounting substrate 1 from being shortened (the height of the space 7 is reduced) when softened, the electronic component 2 and the mounting substrate are prevented. The thermosetting resin 5 buried between 1 works to support the electronic component 2 without being softened by the heating. As described above, the electronic device 10 of the present invention has a small configuration in which the area viewed from above is the same as the size of the electronic device 2, and in addition, in the mounting process, the electronic component 2 and the mounting substrate 1. In order to prevent the distance from being short (the height of the space 7 is low), stable characteristics can be obtained even after mounting.

  Further, in the process of mounting the electronic device 10 on a circuit board such as a mother board using mounting solder, moisture and gas remaining in the resin 5 buried between the electronic component 2 and the mounting board 1 are also shown. Even if the annular brazing material 3 that is heated and rapidly expanded and is remelted and softened is pushed from the outside to the inside of the annular conductor 2c and the annular conductor pad 1c, according to the electronic device 10 of the present invention, the resin 5, a plating film 6 having a higher melting point than the annular brazing material 3 is formed so as to cover the outer surface of the annular brazing material 3, so that the plating film 6 is not remelted and maintains its hardness. It acts as a wall against the pressure from the outside, and it becomes difficult for the remelted annular brazing material 3 to be pushed out of the annular conductor 2c and the annular conductor pad 1c and to flow out. 2b , The occurrence of contact with the terminal electrode pad 1b or the brazing material 4 connecting them is reduced, so that fluctuations in the characteristics of the electronic device 10 after mounting can be suppressed.

  Further, in the electronic device 10 of the present invention, the plating film 6 is formed by electroless plating by immersing the mounted aggregate substrate as a whole in a nickel plating solution. If the outer periphery of the annular conductor pad 1 c is exposed, the plating film 6 can be continuously formed on the exposed portion from the outer surface of the annular brazing material 3. Accordingly, the plating film 6 is formed so as to cover at least part of the outer periphery of the annular conductor 2c on the annular brazing material 3 side and at least part of the outer periphery of the annular conductor pad 1c on the annular brazing material 3 side, As a result, even when the annular brazing material 3 is remelted and softened, the plating film 6 has at least a part of the outer circumference of the annular conductor 2c on the annular brazing material 3 side and at least the annular brazing material 3 on the outer circumference of the annular conductor pad 1c. Since the plating film 6 serving as a wall is difficult to move, the re-melted annular brazing material 3 is pushed out of the annular conductor 2c and the annular conductor pad 1c and flows out. Is more difficult to occur. In order to expose the outer periphery of the annular conductor 2c and the outer periphery of the annular conductor pad 1c during plating, the mounted assembly board is immersed in an acidic or alkaline solution before being entirely immersed in the nickel plating solution. The annular brazing material 3 (usually enveloping with a thickness of about several μm) that wraps around the outer periphery of the annular conductor 2c and the annular conductor pad 1c may be melted and removed.

  Thus, the electronic device 10 of this example can be used as an electronic device having a high Q value using surface acoustic waves. In addition, since it is small and surface-mounted, it is particularly suitable as an electronic device that is mounted on a mother board of a portable information terminal that is required to be miniaturized, such as a mobile phone.

  It should be noted that the present invention is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, an example of the electronic device 10 of the present invention is an electronic device 10 using a surface acoustic wave element as the electronic component 2. In addition, the electronic device 10 of the present invention is a thin film bulk elastic as the electronic component 2. It is also possible to use an element that requires a predetermined space 7 between the mounting substrate 1 and the like using a wave element.

  In the above example, the resin 5 is formed at the four corners between the mounting substrate 1 and the electronic component 2, but has a shape surrounding the entire outer periphery of the annular brazing material 3. The resin 5 may be formed in a ring shape to stabilize the shape of the resin 5.

  In the above-described example, the resin 5 may be formed in a shape that covers from the upper surface of the mounting substrate 1 to the side surface and the upper surface of the electronic component 2. With such a configuration, the resin 5 is an electronic component. It can also serve as protection of 2.

  As the electronic device 10 of the present invention, a sample using a surface acoustic wave element for the electronic component 2 and a multilayer circuit board for the mounting substrate 1 is produced, and the annular brazing material 3 flows out after being mounted on the circuit board Evaluated.

  As the piezoelectric substrate 2a used for the electronic component 2, a lithium tantalate single crystal was used. The conductor pattern such as the IDT electrode 2d, the pair of reflector electrodes 2e, the plurality of terminal electrodes 2b, and the annular conductor 2c surrounding them formed on the lower surface of the piezoelectric substrate 2a has a titanium thin film with a thickness of 6 nm and a thickness of 130 nm. The laminated film was formed by alternately laminating three aluminum and copper thin films.

  The mounting substrate 1 was a collective substrate, and glass ceramics was used as the material of the insulating substrate 1a. Further, the terminal electrode pad 1b and the annular conductor pad 1c formed on the upper surface of the insulating substrate 1a, and the conductor pads such as the external terminal 1d for mounting formed on the lower surface of the insulating substrate 1a are mainly composed of silver having a thickness of 10 μm. A 2 μm nickel film was formed on the surface of the conductor film, and a gold film of 1 μm or less was further formed on the surface.

A tin-antimony solder paste is applied to each mounting substrate 1 of the collective substrate by screen printing or the like so as to cover the terminal electrode pads 1b and the annular conductor pads 1c, and then heated and melted at 210 to 230 ° C. to form solder bumps. Formed. Next, the electronic component 2 is placed on each mounting substrate 1 so that the terminal electrode pad 1b and the terminal electrode 2b, the annular conductor pad 1c and the annular conductor 2c correspond to each other one by one, and heated to 120 to 180 ° C. Then, pressure and ultrasonic vibration were applied to the electronic component 2 from above, and the terminal electrode 2b, the annular conductor 2c, and the solder bump were ultrasonically fused and temporarily fixed. Next, a plurality of temporarily fixed electronic components 2 and an assembly board are put into a chamber, heated at 210 to 230 ° C. in an N ₂ atmosphere to remelt the solder bumps, and then solidified to be brazed material 4 and annular brazing. The material 3 was formed, and a mounted aggregate substrate was produced. Then, the mounted aggregate substrate was entirely immersed in a nickel plating solution and subjected to electroless plating, thereby forming a plating film 6 so as to cover the outer surface of the annular brazing material 3. Furthermore, a resin paste made by mixing a solvent, an epoxy resin, a thermosetting agent, and the like is applied between the upper surface of the mounted assembly board and the electronic component 2 outside the plating film 6, and is then heated in an oven at 150 ° C. A sample of an example of the electronic device 10 of the present invention was produced by heating and curing for 1 hour, and further cutting between adjacent electronic components 2 of the mounted assembly board using a dicing saw. Five samples were prepared.

  Further, as a comparative example, five electronic devices in which the plating film 6 was not formed on the outer surface of the annular brazing material 3 were produced.

  The sample of the embodiment of the electronic device 10 of the present invention and the sample of the comparative example are mounted on a circuit board at a peak temperature of 220 ° C., and the gap (space 7) between the electronic component 2 and the mounting board 1 for each sample. The annular brazing material 3 was cut so as to separate the electronic component 2 and the mounting substrate 1 at an intermediate position, and the state of the annular brazing material 3 flowing into the annular conductor 2c and the annular conductor pad 1c was observed. As a result of observation, in the sample of the example of the electronic device 10 of the present invention, the flow of the annular brazing material 3 to the inside of the annular conductor 2c and the annular conductor pad 1c was not observed. On the other hand, with respect to the sample of the comparative example in which the plating film 6 is not formed on the outer surface of the annular brazing material 3, the annular brazing material is placed at some positions corresponding to the locations where the resin 5 is disposed. A portion of the material 3 flowing out to the inside of the annular conductor 2c and the annular conductor pad 1c was found.

  That is, in the sample of the embodiment of the electronic device 10 of the present invention, the plating film 6 having a higher melting point than the annular brazing material 3 is formed inside the resin 5 so as to cover the outer surface of the annular brazing material 3. Therefore, since the plating film 6 is not remelted and maintains hardness and acts as a wall against pressure from the outside, the remelted annular brazing material 3 is placed inside the annular conductor 2c and the annular conductor pad 1c. It was confirmed that it was less likely to be pushed out and flow out. Therefore, according to the electronic device 10 of the present invention, the occurrence of contact between the annular brazing material 3 and the terminal electrode 2b, the terminal electrode pad 1b or the brazing material 4 connecting them is reduced. It was confirmed that the problem of fluctuations can be reduced.

It is an external appearance perspective view which shows an example of embodiment of the electronic device of this invention. FIG. 2 is a cross-sectional view taken along line A-A ′ of FIG. 1. It is the external appearance perspective view which looked at the electronic component from the downward direction. It is the external appearance perspective view which looked at the board | substrate for mounting from upper direction. It is the figure which expanded the principal part Z of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mounting board 1a ... Insulating substrate 1b ... Terminal electrode pad 1c ... Annular conductor pad 1d ... External terminal 2 ... Electronic component 2a ... Piezoelectric substrate 2b ... Terminal Electrode 2c ... annular conductor 2d ... IDT electrode 2e ... reflector electrode 3 ... annular brazing material 4 ... brazing material 5 ... resin 6 ... plating film 7 ... space
10 ... Electronic device

Claims (2)

  An electronic component in which a plurality of terminal electrodes and an annular conductor surrounding the plurality of terminal electrodes are formed on the lower surface, a terminal electrode pad corresponding to the terminal electrode and an annular conductor pad corresponding to the annular conductor are formed on the upper surface. On the mounting substrate, the terminal electrode and the terminal electrode pad are mounted with a brazing material, and the annular conductor and the annular conductor pad are connected to each other via an annular brazing material. A plating film having a melting point higher than that of the annular brazing material is formed so as to cover the outer surface of the material, and resin is buried between the electronic component and the mounting substrate outside the plating film. An electronic device characterized by the above.   The plating film is formed so as to cover at least a part of the outer periphery of the annular conductor on the annular brazing material side and at least a part of the outer periphery of the annular conductor pad on the annular brazing material side. The electronic device according to claim 1.

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