JP2012209662A - Wafer level package material for surface acoustic wave device, surface acoustic wave device junction wafer using package material, and surface acoustic wave device cut from junction wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package material which forms holes, each of which has a diameter that is substantially the same as a target diameter, when holes are formed in the package material serving as a cap substrate for a surface acoustic wave device, a junction wafer of a wafer level package surface acoustic wave device manufactured from the package material, and the wafer level package surface acoustic wave device which is obtained by being cut from the junction wafer, achieves the size and height reduction while securing the electric characteristics and the reliability, and enables module mounting.SOLUTION: In a wafer level package material for a surface acoustic wave device, holes are formed at least on a single crystal piezoelectric substrate where piezoelectricity is eliminated.

Description

  The present invention relates to a wafer level package application of a surface acoustic wave device, particularly a wafer level package material for a surface acoustic wave device to be used as a hermetically sealing cap (hereinafter also referred to simply as a package material), and an elastic surface using the same The present invention relates to a wave device bonded wafer (hereinafter sometimes simply referred to as a bonded wafer) and a surface acoustic wave device cut therefrom.

  A surface acoustic wave (SAW) device in which a comb electrode for exciting a surface acoustic wave is formed on a piezoelectric substrate is used as a component for frequency adjustment / selection in high frequency communication such as a cellular phone.

  In recent years, mobile phone communication systems have become multiband, and high frequency components used in mobile phones are required to be modularized. Therefore, it is desired that the surface acoustic wave device is miniaturized and thinned while ensuring electrical characteristics and reliability, and evolved into a product form that can be mounted on a module.

As an example of a surface acoustic wave device that realizes such a requirement, a wafer level packaged surface acoustic wave device formed by bonding a piezoelectric substrate and a substrate serving as a cap at a wafer level has been studied.
For example, in Patent Document 1, “a first substrate having a vibration part that generates solid vibration based on an input electric signal, and an electrode pad part for introducing the electric signal into the vibration part; A second substrate having a through hole for connecting an electrode pad portion and an external electrode, wherein at least the vibration portion of the first substrate includes the first substrate, the second substrate, and the second substrate. An elastic wave device characterized in that it is hermetically sealed by bonding of the above is disclosed.

Further, the surface acoustic wave device circuit formed on the LiTaO ₃ substrate, using other LiTaO ₃ substrate made of the same material as the cap substrate, the LiTaO ₃ substrate SAW device circuits are formed (hereinafter, LiTaO ₃ A wafer level packaged surface acoustic wave device obtained by bonding the LiTaO ₃ cap substrate to the SAW substrate is disclosed (Non-patent document 1) (Non-patent document 2).

Here, the LiTaO ₃ substrate used as the cap substrate is formed with a hole having a depth up to the middle of the substrate thickness by sandblasting, filled with copper by electroplating, and a metal layer on the surface with the hole The metal pad is formed in the hole and other necessary portions by patterning. Thereafter, the LiTaO ₃ cap substrate thus obtained is bonded to the LiTaO ₃ · SAW substrate.

Then, the surface of the bonded substrate on the LiTaO ₃ cap substrate side is polished, a hole filled with copper is exposed, and an electrode is formed in the hole where the copper is exposed. Package surface acoustic wave device has been obtained. The wafer level packaged surface acoustic wave device obtained in this way is characterized in that there is no heat warping when the SAW substrate and the cap substrate are joined, and the device is hermetically sealed, so that the reliability is good.

  In particular, in Non-Patent Document 2, the wafer level packaged surface acoustic wave device provides electrical performance, and has a moisture resistance level (MSL) level 1 and saturated vapor required for a highly reliable surface acoustic wave package. The pressure test (PCT) is preferable because it satisfies 96-hour resistance.

  In addition, a wafer level packaged surface acoustic wave device obtained by joining the surface acoustic wave device substrate and the cap substrate using a substrate made of the same material as the surface acoustic wave device substrate as a cap substrate. In addition, the hole diameter of the surface of the wafer level package surface acoustic wave device (Patent Document 2) or the hole of the cap substrate is characterized in that the hole of the cap substrate penetrates to a part of the surface acoustic wave device substrate. A wafer-level packaged surface acoustic wave device (Patent Document 3) is disclosed which decreases in the direction and increases in reverse from a certain depth.

Non-Patent Document 3 discloses a wafer level package device using boundary acoustic waves.
This boundary acoustic wave device is preferred because it satisfies the saturated vapor pressure test (PCT) resistance in the wafer level package device configuration because the elastic wave is confined between the piezoelectric body and the dielectric layer.
However, there is a problem that not all mobile phone bands can be handled due to the nature of boundary acoustic waves, such as a somewhat large loss.

JP 2004-80221 A US Pat. No. 7,755,151B2 US Pat. No. 7,545,017B2 Japanese Patent No. 3,222,072

Proc. IEEE Ultrasonics Symp. pp. 196-199 (2006) "An Ultra Small SAW RF Filtering Wafer Level Packaging Technology" ECS Transactions, 18 (1) pp. 763-768 (2009) "Wafer Level SAW RF Filter Packaging With Through Wafer Interconnection" Proc. IEEE Ultrasonics Symp. pp. 188-191 (2006) "RF Filter using Boundary Acoustic Wave"

  Here, in Non-Patent Documents 1 and 2 and Patent Document 3, a sandblasting method or a laser is used for forming a hole in the cap substrate. However, although the sandblasting method has relatively good productivity, it is difficult to control the hole shape, and there are problems that chips and chipping occur around the hole. In addition, there is a problem that laser processing is expensive.

Non-Patent Document 2 shows a hole formed in a LiTaO ₃ cap substrate by sandblasting. According to this, it is shown that a hole with a diameter of 129.87 μm was formed after sandblasting for a dry film resist hole diameter of 73.23 μm in diameter.
That is, when a hole is formed in the cap substrate using the sand blast method, it is indicated that there is a problem that the hole diameter actually formed in the substrate becomes larger than necessary than the target hole diameter.

  In the surface acoustic wave device, an impedance matching circuit or a phase matching circuit composed of a multilayer ceramic circuit board or the like is used in combination with a circuit using an acoustic wave (see Patent Document 4). When the circuit board is applied as it is to a wafer level packaged surface acoustic wave device, there is a problem that it is difficult to reduce the height of the device.

  In order to solve the above-described problem, in the present invention, when forming a hole in a package material that is a cap substrate for a surface acoustic wave device, a hole having a hole diameter corresponding to the target diameter is accurately formed. Packaging material, wafer level packaged surface acoustic wave device bonded wafer manufactured therefrom, and obtained by cutting from it, and can be reduced in size and height while maintaining electrical characteristics and reliability, and An object of the present invention is to provide a wafer level packaged surface acoustic wave device that can be mounted in a module.

  In order to achieve the above object, the present invention provides a wafer level package material for a surface acoustic wave device, wherein a hole is formed in at least a single crystal piezoelectric substrate from which piezoelectricity has been lost. To do.

In such a package material, since the piezoelectricity is lost, the vibration when the hole is formed in the wafer level package material for the surface acoustic wave device is converted into an electric displacement by the piezoelectric effect, and the electric displacement is reduced. Since no new vibration is generated, it is possible to suppress the occurrence of chipping or chipping particularly at the opening of the hole. Furthermore, since the chipping and chipping do not occur, the opening of the hole formed on the single crystal piezoelectric substrate from which the piezoelectricity has been lost becomes larger than the opening of the mask material used during drilling. It is also possible to suppress the excess, and the drilling can proceed efficiently in the depth direction.
Similarly, even when static electricity is generated when forming the hole, the static electricity is not converted into mechanical displacement by the piezoelectric effect, so that the material such as a wafer is broken by the mechanical displacement. Can be prevented.

  At this time, the surface roughness Ra of the substrate surface on which the holes are formed is preferably 0.3 μm or less.

  If it is such, the film thickness distribution of the package material manufactured can be made more uniform, and the package material can be more firmly bonded to a piezoelectric substrate, a laminated circuit, or the like.

At this time, the single crystal piezoelectric substrate from which the piezoelectricity has disappeared is preferably made of LiTaO ₃ or LiNbO ₃ .

  If it is such, since it can be made the same material as a general piezoelectric substrate for surface acoustic wave devices, the thermal expansion coefficient can be made equal, and at the time of joining such a package material and the piezoelectric substrate Generation of warpage due to heating can be more reliably suppressed. Further, this makes it possible to more effectively hermetically seal the manufactured surface acoustic wave device, and to improve the reliability.

  Also, at this time, a laminated circuit made of at least one kind of resin of polyimide, polyethylene, polytetrafluoroethylene, polyphenylene ether, and benzocyclobutene is formed on one side or both sides of the single crystal piezoelectric substrate from which the piezoelectricity has disappeared. Can be.

  A multilayer circuit made of such a resin can be a low-loss and thin multilayer circuit. By forming such a multilayer circuit on a package material, a surface acoustic wave device manufactured therefrom can be reduced. It can be turned back and more reliable.

  Further, in the present invention, a wafer which is the same material as the wafer level package material for a surface acoustic wave device of the present invention and in which an electrode for detecting surface acoustic wave excitation is formed on a single crystal piezoelectric substrate having piezoelectricity. And a hole formed in the wafer level package material for the surface acoustic wave device on which the multilayer circuit of the present invention is formed is filled with a metal material, and a metal pad is further formed at the position of the hole filled with the metal material. Provided is a wafer level packaged surface acoustic wave device bonded wafer obtained by bonding a wafer level package material for a surface acoustic wave device.

  The present invention also provides a hermetically sealed surface acoustic wave device obtained by cutting the wafer level packaged surface acoustic wave device bonded wafer of the present invention.

  In such a case, as described above, the package material of the present invention as the cap substrate and the piezoelectric substrate have the same thermal expansion coefficient, and a laminated circuit having a low loss and a small thickness is formed. For this reason, it is possible to obtain a bonded wafer and a surface acoustic wave device that are effectively hermetically sealed and reduced in height, and that are more reliable.

As described above, according to the present invention, by using a single crystal piezoelectric substrate that has lost its piezoelectricity during the manufacture of a package material, particularly cracks and chipping at the opening of the hole, and cracking of a material such as a wafer. It can be set as the package material which can prevent.
In addition, a piezoelectric substrate having the same material as the package material and a laminated circuit made of at least one kind of resin selected from polyimide, polyethylene, polytetrafluoroethylene, polyphenylene ether, and benzocyclobutene are formed on one side or both sides. By joining the package material of the present invention, the hermetically sealed and lowered profile can be effectively achieved, and a highly reliable bonded wafer and surface acoustic wave device can be obtained.

It is the figure which showed a part of schematic sectional drawing of the wafer level package material for surface acoustic wave devices of this invention. It is the figure which showed a part of schematic sectional drawing of the wafer level package material for surface acoustic wave devices in which the laminated circuit of this invention was formed. It is the figure which showed a part of schematic sectional drawing of the surface acoustic wave device of this invention. It is the figure which showed the profile of the depth direction of the hole in an Example and a comparative example. It is the figure which showed the electrical property of the surface acoustic wave device of this invention.

  Hereinafter, as an example of a wafer level package material for a surface acoustic wave device according to the present invention, a surface acoustic wave device bonding wafer using the same, and a surface acoustic wave device cut from the wafer level package material, it will be described in detail with reference to the drawings. The present invention is not limited to this.

As shown in FIG. 1, the wafer level package material 1 for a surface acoustic wave device of the present invention has holes 3 formed in a single crystal piezoelectric substrate 2 from which piezoelectricity has been lost.
Examples of a method for eliminating the piezoelectricity from the single crystal piezoelectric substrate include heating at a temperature equal to or higher than the Curie temperature of the single crystal piezoelectric substrate.
Further, the depth of the hole 3 to be formed is not particularly limited, and may be appropriately adjusted according to the thickness of the target surface acoustic wave device wafer level package material. Further, the hole may be penetrated to the back surface of the substrate.

Here, in the drilling of the single crystal piezoelectric substrate 2 from which the piezoelectricity has been lost, the holes 3 can be formed by, for example, a sandblast method.
In this case, when the abrasive grains hit the single crystal piezoelectric substrate 2 from which the piezoelectricity has disappeared, the vibration is converted into an electric displacement by the piezoelectric effect, and the converted electric displacement again causes a new vibration by the piezoelectric effect. There is no generation. For this reason, it can suppress that the crack and chipping in the opening part of the hole 3 arise especially.

  Further, since the chipping and chipping do not occur, the opening of the hole 3 formed on the single crystal piezoelectric substrate 2 from which the piezoelectricity has been lost is more than the opening of the mask material used in the drilling process. It can also be prevented that it becomes too large, and drilling can be efficiently advanced in the depth direction.

  Similarly, when the hole 3 is formed by the sandblast method, the static electricity is not converted into a mechanical displacement by the piezoelectric effect in the single crystal piezoelectric substrate 2 in which the piezoelectricity is lost even if static electricity is generated. Therefore, it is possible to prevent the substrate from cracking due to the mechanical displacement.

Further, if the single crystal piezoelectric substrate 2 from which piezoelectricity has been lost is made of LiTaO ₃ or LiNbO ₃ , it is the same as the single crystal piezoelectric substrate to be bonded to the surface acoustic wave device wafer level package material 1 described later. Since it is made of a material, the thermal expansion coefficient can be made equal, and the occurrence of warpage due to heating during bonding can be more reliably suppressed. Further, this is preferable because the manufactured surface acoustic wave device can be more effectively hermetically sealed and the reliability can be further improved.

  At this time, if the surface roughness Ra of the surface of the substrate on which the holes 3 are formed is 0.3 μm or less, the thickness distribution of the manufactured wafer level package material 1 for surface acoustic wave devices is made more uniform. This is preferable because it can be more firmly bonded to a piezoelectric substrate or a laminated circuit to be bonded thereafter.

The wafer level package material 1 for a surface acoustic wave device manufactured in this way is filled with copper after filling the hole 3 with copper as shown in FIG. 2 and then performing single-side grinding and double-side polishing. A wafer level package material bonded wafer for a surface acoustic wave device is obtained by bonding a surface on the opening side of 3 ′ and a Y-cut single crystal piezoelectric substrate made of LiTaO ₃ or LiNbO ₃ via Au pads 4a and 4b. Manufactured. The Au pad 4a is also electrically joined to the hole filled with copper.

Here, as shown in FIG. 2, the laminated circuit 5 may be formed on the surface of the single crystal piezoelectric substrate 2 from which the piezoelectricity is lost. Although FIG. 2 shows an example in which the piezoelectric crystal is formed only on the surface opposite to the opening of the hole 3 of the single crystal piezoelectric substrate 2, it may be formed on both surfaces.
The laminated circuit 5 can be a matching circuit such as an impedance matching circuit or a phase matching circuit. In the case of the matching circuit, the portion of the laminated circuit 5 corresponding to the hole 3 ′ filled with copper and the Au pad 4 c formed on the surface opposite to the bonding surface of the laminated circuit 5 are composed of copper wiring. 6 is electrically connected.

  Moreover, as a material of the laminated circuit 5, if it is at least one kind of resin among polyimide, polyethylene, polytetrafluoroethylene, polyphenylene ether, and benzocyclobutene, a laminated circuit having a low loss and a small thickness can be obtained. Therefore, it is preferable.

Then, as shown in FIG. 3, a surface acoustic wave device wafer level package material 10 on which the laminated circuit 5 is formed, and an electrode 8 for detecting surface acoustic wave excitation are formed on the substrate, and LiTaO ₃ or LiNbO _3. The surface acoustic wave device 20 is formed by dicing the wafer-level package material bonding wafer for the surface acoustic wave device, which is bonded to the single crystal piezoelectric substrate 7 having piezoelectricity while being hermetically sealed, and is manufactured at room temperature. Is manufactured.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.

Example 1
A 4-inch (100 mm) 36 ° rotated Y-cut LiTaO ₃ single crystal piezoelectric substrate 200 μm thick wafer was prepared. When a synchroscope probe was applied to the center of the wafer and the wafer was struck, a change in potential was detected. Further, when the surface potential of the wafer was observed at 25 ° C. and 200 ° C., they were 0 kV and 3 kV, respectively.
Next, the 36 ° rotated Y-cut LiTaO ₃ single crystal piezoelectric substrate was heated at 900 ° C., which is a Curie temperature of 610 ° C. or more, for 4 hours in an N ₂ atmosphere. A synchroscope probe was applied to the center of the wafer after heating and the wafer was struck, but no change in potential was detected. Further, when the surface potential of the wafer was observed at 25 ° C. and 200 ° C., both were 0 KV.
By the above treatment, the piezoelectricity and pyroelectricity of the 36 ° rotated Y-cut single LiTaO ₃ single crystal piezoelectric substrate were lost.

Next, holes were formed by sandblasting on the entire surface of the 36 ° rotated Y-cut LiTaO ₃ single crystal piezoelectric substrate from which the piezoelectricity had disappeared. Here, the surface of the substrate on which the hole was made was a lapping surface having a surface roughness Ra of 0.12 μm. The sandblast abrasive grains were No. 800 based on alumina, a dry film resist was used as the mask material, and the mask hole diameter was 100 μm.
In the sandblast treatment, the sandblast head was swept over the entire surface of the substrate for 3 minutes, and this was repeated four times. The total number of holes in the substrate surface was about 60,000.

  At this time, when the profile in the depth direction of the hole formed by drilling was measured with a laser microscope, the mask hole diameter was 100 μm, whereas the hole diameter formed on the piezoelectric substrate was 101 μm. It was found that holes with a depth of 180 μm were uniformly formed in the wafer surface. In addition, there is no occurrence of chipping or chipping in the opening of the hole, and the opening of the hole formed on the piezoelectric substrate is not excessively larger than the opening of the mask material. Drilling was able to proceed efficiently in the vertical direction. The aspect ratio (hole depth / hole diameter) of the hole formed at this time was 1.8. The result at this time is shown in FIG.

(Example 2)
After pulling up the piezoelectric single crystal by the pulling method, a 36 ° rotation Y-cut single LiTaO ₃ single crystal piezoelectric substrate obtained from a boule without performing a single polarization treatment for imparting piezoelectricity to the piezoelectric single crystal was used. Except for the above, drilling by the sandblast method was performed in the same manner as in Example 1.
At this time, almost the same result as in Example 1 was obtained.

(Example 3)
Gold was deposited in a thickness of 0.2 μm on the opening surface of the hole of the wafer level package material for the surface acoustic wave device obtained in Example 1 by vacuum deposition.
Next, copper was attached to the wafer level package material for a surface acoustic wave device by an ion plating method, and the hole was filled with copper.
This package material is subjected to single-side grinding and double-side polishing to a thickness of 150 μm, and the outer periphery of the device unit cell (0.8 mm × 0.6 mm size) on the same surface as the opening of the hole and the opening of the hole In this portion, an Au pad was formed with a thickness of 5 μm.

  Next, a laminated circuit (thickness 30 μm) made of benzocyclobutene was formed on the surface opposite to the opening surface of the hole of the wafer level package material for the surface acoustic wave device. Copper was used for the wiring portion of the laminated circuit to form an impedance matching circuit.

Next, a SAW device is formed on a 36-degree rotated Y-cut LiTaO ₃ single crystal piezoelectric substrate (thickness 150 μm) having a piezoelectricity of 4 inches (100 mm) with the same material as the wafer level package material for the surface acoustic wave device. Thus, a SAW device wafer was obtained.

Thereafter, the wafer level package material for the surface acoustic wave device and the SAW device wafer were bonded at the wafer level. The bonding is performed by heating and pressing at a temperature of 300 ° C. under a low vacuum of 1 × 10 ⁻² Pa after cleaning the bonding surface of the surface acoustic wave device wafer level package material and the SAW device wafer, Each device unit cell was hermetically sealed.
An Au pad having a thickness of 5 μm was formed on a portion of the bonded wafer bonded in this way on the outer surface of the unit device cell (0.8 mm × 0.6 mm size) on the surface of the laminated circuit.

This bonded wafer was diced at room temperature to obtain a wafer level package SAW device which is a surface acoustic wave device. When the electrical characteristics of the surface acoustic wave device thus manufactured were measured with a network analyzer, the characteristics shown in FIG. 5 were obtained.
This device was left for 2000 hours in an atmosphere of 85% humidity and 85 ° C., then left for 96 hours in an atmosphere of 100% humidity, 121 ° C. and 2 atmospheres, and 2000 cycles of a heat cycle of −85 ° C. to 125 ° C. When the electrical characteristics after the evaluation were evaluated, the same results as in FIG. 5 were obtained.

(Comparative Example 1)
Except that holes were formed on the substrate surface of the single crystal piezoelectric substrate having piezoelectricity, drilling by the sandblast method was performed in the same manner as in Example 1.
At this time, when the profile in the depth direction of the hole formed by drilling was measured with a laser microscope, the mask hole diameter was 100 μm, whereas the hole diameter formed on the piezoelectric substrate was 135 μm. It was found that holes having a depth of 120 μm were uniformly formed in the wafer surface. Further, chipping or chipping with a width of 15 μm occurred in the opening of the hole, and the opening of the hole formed on the piezoelectric substrate became extremely larger than the opening of the mask material. The aspect ratio (hole depth / hole diameter) of the hole formed at this time was 0.9. The result at this time is shown in FIG.

(Comparative Example 2)
Except that a 4-inch (100 mm), 36-degree rotated Y-cut LiTaO ₃ single crystal piezoelectric substrate having piezoelectricity is used, the substrate surface to be perforated is a lap surface with a surface roughness Ra of 0.5 μm. When the hole was drilled by sandblasting as in No. 1, many large chips and chipping occurred in the opening of the hole, and the adhesion between the piezoelectric substrate having the piezoelectric property and the dry film resist was poor, and the periphery of the hole As a result, the dry film resist peeled off and the hole diameter could not be controlled. That is, a wafer level package material for surface acoustic waves could not be manufactured.

From the examples and comparative examples, by using a single crystal piezoelectric substrate that has lost its piezoelectricity, it is possible to suppress the occurrence of chipping and chipping at the opening of the hole during drilling, and further during drilling It is also possible to prevent the opening of the hole formed on the single crystal piezoelectric substrate from which the piezoelectricity has been lost from becoming too large compared to the opening of the mask material used, and to efficiently drill in the depth direction. It can be seen that the processing can proceed.
Furthermore, by bonding the package material manufactured in this way and a single crystal piezoelectric substrate having piezoelectricity, it is possible to effectively hermetically seal and reduce the height, and to achieve a highly reliable bonded wafer and elasticity. It can be seen that a surface wave device can be manufactured.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

1 ... Wafer level package material for surface acoustic wave devices,
2 ... single crystal piezoelectric substrate from which piezoelectricity has been lost, 3 ... hole, 3 '... hole filled with copper,
4a, 4b, 4c ... Au pad, 5 ... laminated circuit, 6 ... copper wiring,
7: Single crystal piezoelectric substrate having piezoelectricity 8: Electrode for detecting surface acoustic wave excitation,
10: Wafer level package material for surface acoustic wave device in which laminated circuit is formed,
20: Surface acoustic wave device.

Claims (6)

  A wafer level package material for a surface acoustic wave device, wherein a hole is formed in at least a single crystal piezoelectric substrate from which piezoelectricity has disappeared.   2. The wafer level package material for a surface acoustic wave device according to claim 1, wherein the surface roughness Ra of the substrate surface on which the holes are formed is 0.3 μm or less. 3. _{3. The} wafer level package material for a surface acoustic wave device according to claim 1, wherein the single crystal piezoelectric substrate from which the piezoelectricity has disappeared is made of LiTaO ₃ or LiNbO ₃ .   A laminated circuit made of at least one kind of resin selected from polyimide, polyethylene, polytetrafluoroethylene, polyphenylene ether, and benzocyclobutene is formed on one side or both sides of the single crystal piezoelectric substrate from which the piezoelectricity has been lost. The wafer level package material for a surface acoustic wave device according to any one of claims 1 to 3, wherein the wafer level package material is a material for a surface acoustic wave device. A surface acoustic wave excitation detection electrode is formed on a single crystal piezoelectric substrate that is the same material as the wafer level package material for a surface acoustic wave device according to any one of claims 1 to 3. A wafer that has been
5. The surface acoustic wave device according to claim 4, wherein a hole formed in the wafer level package material for a surface acoustic wave device is filled with a metal material, and a metal pad is formed at a position of the hole filled with the metal material. Wafer level packaging material;
Wafer level packaged surface acoustic wave device bonded wafer formed by bonding.   A hermetically sealed surface acoustic wave device obtained by cutting the wafer level packaged surface acoustic wave device bonded wafer according to claim 5.

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