JP3716123B2 - Surface acoustic wave device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resonator and a surface acoustic wave device for a frequency band filter incorporated in a mobile radio device such as a car phone and a mobile phone.
[0002]
[Prior art]
In recent years, many SAW resonators and SAW filters have been used as electronic components such as frequency filters (hereinafter referred to as filters), delay lines, transmitters, and the like for bandpass filters for electronic devices that communicate using radio waves. Yes. In particular, in the field of mobile communication, it is frequently used as a filter for RF (Radio Frequency: radio frequency or high frequency) blocks and IF (Intermediate Frequency) blocks of mobile terminal devices such as mobile phones. In the future, it is desired to reduce the weight, thickness, or size of parts in a communication system using mobile wireless devices such as automobile phones and mobile phones.
[0003]
The basic configuration of a conventional surface acoustic wave (hereinafter abbreviated as SAW) device is that a plurality of pairs of comb-like electrodes (inter digital transducer, hereinafter abbreviated as IDT electrodes) are mounted on a piezoelectric substrate. A reflector for efficiently resonating the SAW is arranged on the SAW propagation path excited from the IDT electrode.
[0004]
FIG. 16 shows an example of a conventional SAW device J. The IDT electrode 12 is formed on a piezoelectric substrate 1 made of, for example, a 36 ° Y-cut X-propagating lithium tantalate single crystal or the like, and a conductive material such as aluminum or an aluminum-copper alloy is finely formed by a photolithography method by vapor deposition or sputtering. A pattern is formed to be an electrode.
[0005]
Further, the surface acoustic wave element M configured as described above is accommodated in a case made of ceramic (consisting of a package base 20, a sealing material 22 provided on the case, and a case cap 21), and input / output electrodes. 3, 4 or the ground electrode 5 is connected to the respective lead electrodes 18 and 19 by a wire 25 or connected by a flip chip method using solder bumps.
[0006]
Further, in the absence of the protective film 2, it is necessary to seam weld the element holding substrate and the cap that have a structure capable of maintaining airtightness in order to improve the weather resistance, or to accommodate them in a case sealed with solder and resin. was there.
[0007]
A surface acoustic wave filter for mobile communication is required to have a low mounting area, a low weight, and a low profile to the limit in order to reduce the size of an intensifying mobile phone terminal. Conventionally, a flip-chip mounting method is known as a method for realizing mainly a low mounting area and a low profile.
[0008]
However, the surface acoustic wave device that has been subjected to the flip chip mounting method needs to maintain the degree of freedom of the vibration surface of the excitation electrode formed on the piezoelectric substrate and the airtightness of the device surface portion. Therefore, the clearance of the die attach part to the element and the air tightness of the seal part must be compatible.
[0009]
For example, in the case of a ceramic package, the package is enlarged to satisfy the above functions, the package size is increased by about 1.5 to 1.8 mm per side than the element size, and the bottom area is about 5 times or more. This hindered the reduction in area.
[0010]
[Problems to be solved by the invention]
However, when a conventional surface acoustic wave device is mounted on an external circuit board, it needs to be housed in a housing as described above, and to be electrically connected by forming a wire bond or bump or removing a protective film, There is a problem that becomes very complicated.
[0011]
In addition, the surface acoustic wave device is large in a mounted state and has poor weather resistance in the absence of a protective film, so that it is difficult to directly connect to a housing or an external circuit board that can be easily placed and accommodated.
[0012]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a surface acoustic wave device that simplifies the electrical connection method, facilitates mounting and housing in a housing, and can be directly mounted on an external circuit board. .
[0013]
[Means for Solving the Problems]
In order to solve the above problems, a surface acoustic wave device according to the present invention includes a surface acoustic wave element in which an excitation electrode is formed on the bottom surface of a piezoelectric substrate on a substrate on which a conductor pattern for input / output signals is formed. A surface acoustic wave device comprising: a conductive particle comprising a high-temperature solder containing 50% by volume or less of Au—Sn or Ag—Sn as a component in a dielectric between the lower surface of the piezoelectric substrate and the substrate. The excitation electrode and the conductor pattern are electrically connected to each other with a frame-shaped adhesive dispersed therein, the input / output signal band is 900 MHz, and the diameter of the conductive particles is 30 to 80 μm. It is characterized by that.
[0015]
Further, the distance between the surface of the substrate and the surface of the excitation electrode is set to a distance equal to or greater than the wavelength of the surface acoustic wave.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a surface acoustic wave device according to the present invention will be described below in detail with reference to the drawings.
[0017]
FIG. 1 is a plan view schematically showing the state of the surface acoustic wave device S1 of the reference example placed on the external circuit board K or the package base, and FIG.
[0018]
On the lower surface of the piezoelectric substrate 1, comb-like IDT electrodes 12 that are excitation electrodes for exciting SAW and lead electrodes 3 and 4 that are input / output conductor patterns are formed by a photolithography process. Below the electrode 3,4,5,12, for example a protective film 2 is a dielectric layer made of SiO ₂ is formed, and to have a weather resistance against dirt and moisture. Below this, electrode layers 6, 7, and 8 made of Au formed by mask vapor deposition are formed in the formation region of the lead wiring of the external circuit board K. The electrode layers 6, 7, and 8 and the external circuit board K are formed. The lead-out wiring portions 9, 10, 11 and the conductive resin layer 13 are conductively bonded. Note that the bumps 14 and 14 of the surface acoustic wave device S2 shown in FIG. 3 may be used as the connection member.
[0019]
As described above, the surface acoustic wave devices S1 and S2 are formed on the substrate (package substrate or external circuit substrate) on which the lead-out wiring portions 9, 10, and 11 that are conductor patterns for input / output signals are formed. The surface acoustic wave element F1 having the excitation electrode 12 formed on the lower surface is disposed, and the conductor pattern and the excitation electrode 12 are capacitively coupled via a dielectric layer to input / output an electric signal. ing. The dielectric layer covers the excitation electrode 12. However, if the dielectric layer is formed in a frame shape and airtightness can be secured, the excitation electrode 12 may not be protected. The dielectric is a substance having a specific resistance value of 1 × 10 ⁵ Ωcm or more.
[0020]
The distance h between the surface of the external circuit board K or the substrate and the surface of the excitation electrode 12, that is, the distance h in the vibration space 16 of the excitation electrode 12 is set to a distance equal to or greater than the wavelength of the surface acoustic wave to propagate. And
[0021]
In addition, a chip inductor can be mounted on the external circuit board K between the input signal line 9 and the ground signal line 11 or between the output signal line 10 and the ground signal line 11, or in a zigzag shape. Alternatively, a meandering wiring pattern is formed. That is, the meandering wiring 30 may be formed on or in the external substrate circuit K shown in FIG. Further, as shown in FIG. 5, it is also possible to form a meandering wiring 31 on or inside the package base 20 and cancel unnecessary capacitance with such an inductor. Note that reference numerals 17, 18, and 19 in FIG. 5 denote an extraction input electrode, an extraction output electrode, and a ground electrode, respectively.
[0022]
Next, an equivalent circuit in the surface acoustic wave device S1 is shown in FIG. As shown in this figure, the capacitances C1 to C3 connected in series to the connection portion of the surface acoustic wave element F1 and the inductances D1 and D2 connected in parallel to the external circuit board K are in a resonance state, and transmission in the above circuit is performed. As shown in FIG. 7, the electrical characteristics of the surface acoustic wave device S1 can be obtained by making the resonance frequency substantially coincide with the pass band of the surface acoustic wave element F1. Of course, a structure in which the surface acoustic wave element F1 is mounted on the package substrate 20 as shown in FIGS. That is, as in the surface acoustic wave device S3 shown in FIG. 8, the surface acoustic wave element F1 is placed in the package in which the lid 21 is joined to the base body 20 to which the wirings 18, 19 and the like as input / output conductor patterns are applied. The surface acoustic wave element F1 is placed on the base 20 on which the wirings 18, 19 and the like as input / output conductor patterns are applied, as in the surface acoustic wave device S4 shown in FIG. The pattern and the excitation electrode 12 may be capacitively coupled via the protective film 2 that is a dielectric layer.
[0023]
The piezoelectric substrate 1 is mainly applied to lithium tantalate single crystal, lithium niobate single crystal, crystal, lithium tetraborate single crystal, single crystal having a langasite structure, potassium niobate single crystal, and gallium arsenide single crystal. Is possible.
[0024]
The material of the IDT electrode 12 is mainly applicable to aluminum, aluminum / copper alloy, aluminum / titanium alloy, aluminum / silicon alloy, gold, silver, silver / palladium alloy. In addition, aluminum, aluminum / copper alloy, aluminum / titanium alloy, aluminum / silicon alloy, gold, silver, silver / palladium alloy can be mainly used as the material of the lead electrode, improving electrode adhesion and reducing electrical resistance. Therefore, when a base material is required, chromium, titanium and copper are mainly applicable.
[0025]
The protective film 2 may be made of silicon oxide, silicon nitride, silicon, DLC (Diamond Like Carbon), zinc oxide, polyimide resin, fluorine resin, olefin resin, or positive resist used in a wafer process. Such a photosensitive curable resin is mainly applicable.
[0026]
Further, as shown in FIG. 10, the members of the IDT electrode 12, the input / output electrodes 3 and 4, and the ground electrode 5 are made of aluminum or an alloy containing aluminum as a main component, and the electrode surface is oxidized by an anodic oxidation method. A surface acoustic wave device S5 in which the surface acoustic wave element F2 serving as the protective film 15 of the dielectric layer is placed on the external circuit board K can also be used.
[0027]
Further, as shown in FIGS. 11 and 12, the excitation electrode 12 is a surface acoustic wave element F3 that does not cover a protective film, and a frame-like glass material 24 is provided around the external circuit board or package base to improve weather resistance. The surface acoustic wave device S6 may be provided on the surface 20 and hermetically sealed. Also in this case, in order to ensure the vibration space 16 of the excitation electrode 12, the distance h between the surface of the substrate 20 and the surface of the excitation electrode 12 is set to a distance equal to or greater than the wavelength of the surface acoustic wave. Here, the glass material 24 is applied in a frame shape to the lower surface of the surface acoustic wave element or its outer periphery so as to include the input / output of the surface acoustic wave element and the ground electrodes 4, 5, etc., and the element is mounted on the housing connection substrate. Put. Then, for example, the gap 16 is pressurized while being adjusted, heated to 320 ° C., cured by glass, and sealed.
[0028]
In FIG. 1, the surface acoustic wave element is shown as a resonator ladder type filter. However, the surface acoustic wave element may be a resonator lattice type filter, a double mode resonator type filter, a multi-IDT electrode type filter, or a combination thereof. I do not care. Further, the present invention is not limited to the above-described embodiment, and the present invention can be applied not only to the SAW filter but also to the SAW duplexer, and various modifications can be made without departing from the gist of the present invention.
[0029]
[Embodiment] FIG. 13 is a schematic plan view of the surface acoustic wave device S7 as viewed from above. FIG. 14 is an end view taken along line BB. In the figure, the same members as those in the reference example of FIG.
[0030]
As shown in FIG. 13, the surface acoustic wave device S7 has an elastic surface in which an excitation electrode 12 is formed on the lower surface of the piezoelectric substrate 1 on a base 20 on which electrodes 18 and 19 which are conductor patterns for input / output signals are formed. The wave element F4 is disposed, and the conductivity between the lower surface of the piezoelectric substrate 1 and the substrate 20 is 50% by volume or less (more preferably, 10 to 30% by volume) in the dielectric. A frame-shaped adhesive 41 in which particles 42 are dispersed is interposed, and the excitation electrode 12 and the electrodes 18 and 19 are electrically connected. Reference numeral 44 denotes a package lid 44, and a conductive adhesive 43 for preventing the influence of external electromagnetic waves is interposed between the lower surface of the package lid 44 and the piezoelectric substrate 1.
[0031]
Specifically, a surface acoustic wave element F4 in which a plurality of excitation electrodes formed by connecting at least a pair of comb-like electrode fingers on the lower surface of the piezoelectric substrate 1 is arranged on a package substrate 20 made of ceramic or the like. It is implemented face down.
[0032]
Further, a dielectric (a material having a specific resistance value of 1 × 10 ⁵ Ωcm or more, for example, a thermosetting resin such as glass, epoxy resin, silicone resin, polyimide resin, etc.) that joins the ceramic substrate 20 and the surface acoustic wave element F4. , Photosensitive curable resin, etc.) with conductive particles whose size is controlled almost uniformly (for example, those having a specific resistance value of 1.0 × 10 ⁻⁵ Ωcm or less, Au—Sn alloy, Ag—Sn alloy) Solder ball filler) 6 is mixed in a certain amount, and the adhesive obtained in this way is printed on the electrode forming surface of the surface acoustic wave element F4 so as not to touch the IDT electrode portion, and is mounted on the package face down. Thus, it is possible to effectively secure the space 16 necessary for exciting the surface acoustic wave and to electrically connect the surface acoustic wave element electrode and the electrode of the package base simultaneously. The atmosphere during face-down mounting is preferably inert Ar gas or N ₂ gas.
[0033]
Thereby, it is possible to obtain a surface acoustic wave device structure having a low area and a low back to the ultimate. At this time, the diameter of the conductive particles mixed with the insulating resin is within a range that does not hinder the excitation of the surface acoustic wave, considers the influence of the ground capacity between the surface acoustic wave element electrode and the ground, and further the electric Is determined by mechanical performance. Usually, it is desirable to reduce the capacitive component as much as possible, except when omitting the connection of the electrodes by capacitive coupling. In view of the above reasons, when the band is 900 MHz, the diameter of the conductive particles is in the range of about 30 to 80 μm. If the thickness is 30 μm or less, the ground capacity is excessively increased, and if it is 80 μm or more, a problem occurs in the mechanical strength of the solder. The conductive particles use high-temperature solder in consideration of the heating temperature at the time of mounting on the board.
[0034]
Since the conductive particles are uniformly present in the device electrode and other locations, when the device electrode 2 and the package electrode are designed, a short circuit between the electrodes is prevented. Preferably, a ground electrode is disposed on the package side so that external noise from the side surface portion can be blocked. Further, if the mixing ratio of the conductive particles is 50% or less by volume, the adjacent conductive particles do not come into contact with each other, but 10% to 30% can be said to be a preferable range in consideration of manufacturing stability.
[0035]
Next, the conductive adhesive 43 is printed on the lower surface of the package lid 44 and mounted on the surface acoustic wave element F4 mounted on the bottom of the package.
[0036]
Next, the insulating adhesive 41 is cured by heating. At this time, a load such as a weight is applied from the upper surface of the element so that the conductive particles 6 are in contact with both the surface acoustic wave element electrode 2 b and the package electrode 7. Further, the conductive particles are solder balls, which can be melted and the element common electrode 2b and the package electrode 7 can be electrically joined. At this time, the solder ball is a high-temperature solder containing Au-Sn or Ag-Sn as a component with little solder biting. A heating furnace is used for joining the solder balls. For example, in consideration of the peak temperature of high-temperature solder, it is preferable that the temperature of the heating furnace is welded at a peak temperature of 260 ° C. to 280 ° C.
[0037]
【Example】
[Reference Example] A reference example for producing the surface acoustic wave device shown in FIG. 1 will be described. First, on a piezoelectric substrate made of a 42 ° Y-cut X-propagating lithium tantalate single crystal, a ladder-type series arm resonator in which the IDT electrode 12 has a periodic length of 1.99 μm, a logarithm of 110 pairs, and a crossing width of 39.8 μm. Three ladder-type parallel arm resonators having a period length of 2.1 μm, a logarithm of 75 pairs, and a crossing width of 42.0 μm, and reflectors (20 in number) at both ends of each resonator Provided. In addition, each electrode was formed by depositing an Al—Cu alloy with a film thickness of 2000 mm by a sputtering method, and was patterned by a photolithography process normally performed in a wafer process. The protective film 2 was formed by coating the material SiO ₂ on the entire surface of the element with a thickness of 500 mm by sputtering. After that, in order to form the connection electrodes 6, 7, 8 having an area of 500 μm × 500 μm, a material Au was deposited by a vapor deposition method using a metal mask.
[0038]
On the other hand, on the external circuit board, the lead lines 9, 10, and 11 are matched to the shape of the apparatus according to the present invention, the copper epoxy glass epoxy resin board is 0.5 mm thick, and between the input / output line and the ground line. A 1 nF chip inductor was soldered and mounted.
[0039]
Next, the main material Ag and a conductive resin whose adhesive is an epoxy resin were applied to the connection electrodes 6, 7, and 8 of the surface acoustic wave device with a thickness of 10 μm by a transfer method and placed on the external circuit board.
[0040]
FIG. 15 shows an electrical characteristic evaluation of the surface acoustic wave device according to the present invention. In the evaluation method, a 3.5 mm diameter SMA connector was connected to the input / output terminals of the external circuit board assembled as described above, and measurement was performed with a network analyzer. From the results of FIG. 15, it was found that the transmission amount is 2 dB and the maximum standing wave ratio (VSWR) in the passband is 1.7, which is a good value.
[0041]
[Embodiment] Next, an embodiment of the surface acoustic wave device shown in FIGS. 13 and 14 will be described. A surface acoustic wave filter forming a ladder circuit was manufactured by manufacturing an IDT electrode as an excitation electrode on a piezoelectric substrate made of a lithium tantalate single crystal of 42 ° Y-cut X propagation using a lift-off process. This surface acoustic wave filter was used for transmission with a specific bandwidth of 2.6% in the 900 MHz band, and the electrode width and electrode space of the comb-like IDT electrode were each about 1 μm.
[0042]
The configuration of the filter is a π-type ladder circuit using five surface acoustic wave resonators, and the electrodes of each surface acoustic wave resonator are connected in series and parallel to obtain low loss and high out-of-band attenuation. The maximum capacity ratio is taken.
[0043]
The structure of the surface acoustic wave resonator is such that the number of electrode fingers of the IDT electrode is about 60 to 130 pairs, the crossing width is 15λ to 30λ (where λ is the wavelength of the surface acoustic wave), and the electrode material is formed by EB evaporation. Aluminum having a thickness of 4100 mm was used.
[0044]
Further, since the bonding between the surface acoustic wave element and the package base is performed by high-temperature solder, corrosion occurs in the single-layer film of aluminum. For this reason, a nickel plating film (thickness of about 0.5 μm) is formed on the bonding portion by sputtering, and a gold plating film (thickness of about 0.1 μm) is similarly formed thereon to ensure solder wettability. The film was formed by DC sputtering.
[0045]
The lithium tantalate piezoelectric substrate on which the surface acoustic wave device was manufactured was 0.35 mm thick. This is because if the piezoelectric substrate is thicker than this, it will affect the total thickness of the device and hinder the low profile, and if it is less than this, the wafer will be easily damaged during electrode processing, and the yield will be significantly reduced. It is to do. In order to make the total thickness 1 mm or less, the ceramic thickness of the bottom of the package was 0.35 mm for a single plate, and the thickness of the lid was 0.15 mm.
[0046]
The wafer was divided using a dicing saw and cut with a diamond abrasive grain # 600 at a pitch of about 1 mm square.
[0047]
The die bonding pattern was formed by adsorbing the diced wafer on a flat substrate to produce a thick film printing screen mask and printing. The adhesive used at this time was an insulating one-part epoxy adhesive, and a low-thixotropic and low-solvent thermosetting type was selected.
[0048]
Solder balls having a diameter of about 50 μm were used to obtain electrical bonding, and were mixed at a volume ratio of 20% with respect to the above-mentioned adhesive.
[0049]
Also, when the adhesive is cured, a load is applied aiming at the area where the solder ball is slightly deformed so that the solder ball does not separate from the surface acoustic wave element electrode and the package electrode due to the expansion of the adhesive during solvent removal. did. The desired curing was obtained with a heating temperature of about 150 ° C. and a time of 1 hour. Thereafter, the peak temperature was heated to about 320 ° C. with a load applied, and the surface acoustic wave device electrode and the package electrode were joined by solder balls. About the cover body, the conductive epoxy adhesive material was apply | coated to the lower surface, and it mounted on the surface acoustic wave element.
[0050]
A network analyzer was used to measure the characteristics, and good characteristics could be confirmed at 900 MHz.
[0051]
In the present invention, a ladder type surface acoustic wave device has been described, but it goes without saying that it can also be applied to a surface acoustic wave device of a transversal type or a resonator type. In addition to the solder balls used to obtain the electrical connection, a metal ball having a slightly smaller diameter than the solder balls is mixed with the solder balls, so that the micro wave between the surface acoustic wave element and the package is mixed. Examples include a method of controlling the gap, and a method of using a soldered copper ball as an alternative to the solder ball.
[0054]
【The invention's effect】
By using an adhesive in which an appropriate amount of conductive particles are dispersed in a dielectric, it is possible to obtain electrical and mechanical joints between the surface acoustic wave element and the package at the same time. Therefore, expensive wires such as conventional wire bonders and bump bonders are used. The equipment and materials can be dispensed with, the treatment with a high-throughput heating furnace can be performed, and the production can be simplified and speeded up.
[0055]
In addition, the free vibration space (microgap) for surface acoustic waves required between the surface acoustic wave element and the package electrode can be easily controlled by, for example, the particle size of the solder ball, so that the surface acoustic wave filter and the ground electrode are Therefore, the ground capacity generated in the surface can be controlled with high accuracy, the reproducibility of the characteristics at the time of design is improved, and the surface acoustic wave device can be lowered.
[0056]
In addition, since there is no need to obtain airtightness with a package as in the past, it is not necessary to provide a cavity structure in the package, and the surface acoustic wave device can be significantly reduced in area (less than about 1/4 of the conventional one). As a result, it can contribute to miniaturization, weight reduction, and cost reduction of the mobile phone.
[Brief description of the drawings]
FIG. 1 is a diagram schematically illustrating a surface acoustic wave element mounting structure (surface acoustic wave device) according to a reference example, and is a partially broken view schematically showing how a surface acoustic wave device is mounted on a substrate. It is a top view.
FIG. 2 is an end view taken along line AA in FIG.
FIG. 3 is a cross-sectional view schematically illustrating a surface acoustic wave device of a reference example.
FIG. 4 is a schematic plan view illustrating a correction circuit formed on an external circuit board.
FIG. 5 is a schematic plan view illustrating a correction circuit formed on a package substrate.
FIG. 6 is an equivalent circuit diagram of a surface acoustic wave device of a reference example.
FIG. 7 is a diagram showing a transmission amount of a surface acoustic wave device of a reference example.
FIG. 8 is a cross-sectional view schematically illustrating a surface acoustic wave device of a reference example.
FIG. 9 is a cross-sectional view schematically illustrating a surface acoustic wave device of a reference example.
FIG. 10 is a cross-sectional view schematically illustrating a surface acoustic wave device of a reference example.
FIG. 11 is a cross-sectional view schematically illustrating a surface acoustic wave device of a reference example.
12 is a plan view schematically showing the surface acoustic wave device of FIG. 11. FIG.
FIG. 13 is a diagram schematically illustrating a surface acoustic wave element mounting structure (surface acoustic wave device) according to the present invention, and is a plan view schematically illustrating how the surface acoustic wave element is mounted on a substrate. is there.
14 is an end view taken along line BB in FIG.
FIG. 15 is a result of evaluating electrical characteristics of the surface acoustic wave device according to the present invention.
FIG. 16 is a cross-sectional view schematically illustrating a conventional surface acoustic wave device.
[Explanation of symbols]
1: piezoelectric substrate 2: protective film 3: input electrode 4 on piezoelectric substrate 4: output electrode 5 on piezoelectric substrate 5: ground electrode 6 on piezoelectric substrate: lead-out input electrode 7: lead-out output electrode 8: ground electrode 7 ': base Electrode 8 ': Base electrode 9: Input electrode 10 of external circuit board: Output electrode 11 of external circuit board: Ground electrode 12 of external circuit board: IDT electrode 13: Conductive resin 14: Bump 15: Anodized film 16: Gap 17: Case side lead input electrode 18: Case side lead output electrode 19: Case side ground electrode 20: Case side connection substrate 21: Case cap 22: Sealing material 30, 31: Serpentine inductor wiring 24: Glass sealing material 25: Wires F1 to F4: Surface acoustic wave elements S1 to S7: Surface acoustic wave device K: External circuit board

Claims (2)

A surface acoustic wave device in which a surface acoustic wave element in which an excitation electrode is formed on a lower surface of a piezoelectric substrate is disposed on a substrate on which a conductor pattern for input / output signals is formed. A frame-shaped adhesive in which conductive particles made of high-temperature solder containing 50% by volume or less of Au-Sn or Ag-Sn as a component are interposed in a dielectric, and the excitation electrode A surface acoustic wave device characterized in that the conductive pattern is electrically connected, the band of the input / output signal is 900 MHz, and the diameter of the conductive particles is 30 to 80 μm . 2. The surface acoustic wave device according to claim 1, wherein a distance between the surface of the substrate and the surface of the excitation electrode is set to a distance equal to or greater than the wavelength of the surface acoustic wave.

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