JPH098595A - Surface acoustic wave device and manufacture therefor - Google Patents

Abstract

PURPOSE: To provide a surface acoustic wave device which is suitable for a batch processing and mass-production and manufacuring method therefor. CONSTITUTION: On a piezoelectric substrate 11, a surface acoustic wave element group 12 composed of plural surface acoustic wave elements and take-at electrodes (an input/output terminal 13 and an earth terminal 14) to be connected with each surface acoustic wave element are formed. On the whole surface of the piezoelectric substrate 11 on which the surface acoustic wave element group 12 and the take-out electrodes are formed, the coating of thin film material 15 is performed. The conver material having a recessed part in the part opposite to the surface acoustic wave propagation area in the acoustic surface wave element is directly joined to the piezoelectric substrate 11 for which the coating of thin film material 15 is performed. After the surface acoustic wave element is segmented into each piece and the take-out electrodes are exposed to an end face, the take-out electrodes exposed to the end face are connected with an external electrode 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave device used for a high frequency filter for transmission and reception in mobile communication equipment and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the spread and development of mobile communication equipment, further miniaturization of a surface acoustic wave device, which is one of the constituent elements, is required.

FIG. 10A shows a schematic view of a conventional surface acoustic wave device. As shown in FIG. 10A, a piezoelectric substrate 119 is fixed in the ceramic package 118 with an adhesive 117. A surface acoustic wave element 113 and an electrode pad 112 are formed on the piezoelectric substrate 119. The extraction electrode 11 is included in the package 118.
6 is provided, and the extraction electrode 116 is connected to the electrode pad 112 via the bonding wire 114. Further, the cap 1 made of metal or ceramic is formed on the upper end of the ceramic package 118 by using the solder 115.
11 is attached.

This conventional surface acoustic wave device is manufactured as follows. That is, a plurality of surface acoustic wave elements 113 and electrode pads 11 are formed on the wafer of the piezoelectric substrate 119.
2 are formed and divided into individual pieces using a cutting device such as a dicing saw. The divided pieces are fixed one by one in the package 118 using the adhesive 117, and wire bonding for electrode extraction is performed. After that, the cap 111 is sealed to the package 118, and the surface acoustic wave element 113 is hermetically sealed.

[0005]

However, FIG. 10 (a)
In the conventional surface acoustic wave device as shown in FIG. 2, the IDT electrode on the surface acoustic wave element 113 due to the pyroelectricity of the piezoelectric substrate 119 is subjected to a process involving heating and cooling of the substrate such as dicing and wire bonding. There is a risk that a wire break may occur due to discharge between the (comb electrodes). Further, in the step of encapsulating the surface acoustic wave element 113 in the package 118, solder splashes from the sealing portion of the cap 111, fixing resin, etc. adhere to the IDT electrodes, and the characteristics of the surface acoustic wave element 113 are changed or deteriorated. There was a risk of causing it. Further, even after the surface acoustic wave element 113 is sealed in the package 118, gas may be released from the adhesive 117 existing in the package 118, and the characteristics of the surface acoustic wave element 113 may be changed. In addition, each of the surface acoustic wave elements 113 is treated separately, and is packaged separately.
Since the surface acoustic wave element 113 is mounted in the board 18, the frequency of the surface acoustic wave element 113 becomes high, and when the surface acoustic wave element 113 is miniaturized, it becomes very difficult to handle it, resulting in an increase in production cost and a decrease in mass productivity. I was invited. Furthermore, many of the piezoelectric substrates forming the surface acoustic wave element 113 have poor frequency temperature characteristics, and it has been difficult to construct a filter that passes a certain frequency band in a wide temperature range.

Further, in the structure that requires the bonding wire 114 as shown in FIG. 10A, the inductive component parasitic on the wire deteriorates the characteristics of the device at a high frequency, which causes an obstacle to the high frequency of the element. Was becoming. Furthermore, since an electrode pad for connecting the bonding wire 114 is required on the piezoelectric substrate 119 and the ceramic package 118, the entire surface acoustic wave device is larger than the size of the surface acoustic wave element 113. It was

Therefore, there has been proposed a face-down mounting method which does not use a bonding wire as shown in FIG. 10 (b). As shown in FIG. 10B, the electrode pad 112 on the piezoelectric substrate 119 has the metal bump 120.
It is connected to the extraction electrode 116 of the package 118 via. Since other configurations are the same as those in FIG. 10A, the same members are designated by the same reference numerals and the description thereof will be omitted.

However, in the surface acoustic wave device manufactured by the face-down mounting method as described above, the metal bump 1
Since the strength of the connecting portion between 20 and the take-out electrode 116 is not sufficient, there is a problem that it is weak against impact. Further, the conventional problems have not been completely solved in that individual handling is required.

In order to solve the above problems in the prior art, it is an object of the present invention to provide a surface acoustic wave device suitable for mass production and a method for manufacturing the same.

[0010]

To achieve the above object, a surface acoustic wave device according to the present invention has a structure in which a surface acoustic wave element is connected to a surface acoustic wave element on a piezoelectric substrate. A surface acoustic wave device including at least an extraction electrode extended to an end face of a substrate, which is directly bonded to the piezoelectric substrate via an insulating thin film material existing on the surface acoustic wave element and the extraction electrode. It is characterized by including a lid member and an external electrode connected to the extraction electrode exposed at an end portion of a bonding interface between the piezoelectric substrate and the lid member.

Further, in the structure of the surface acoustic wave device of the present invention, it is preferable that the lid member has a recess in a portion of the surface acoustic wave element facing the surface acoustic wave propagation region. Further, in the structure of the surface acoustic wave device of the present invention, it is preferable that the thin film material is completely removed only on the surface acoustic wave propagation region of the surface acoustic wave element.

Further, in the structure of the surface acoustic wave device of the present invention, it is preferable that the thin film material is removed only on the surface acoustic wave propagation region of the surface acoustic wave element, leaving a predetermined film thickness. Further, in this case, it is preferable that the predetermined film thickness is equal to or less than the propagation wavelength of the surface acoustic wave element.

Further, in the structure of the surface acoustic wave device of the present invention, it is preferable that the thin film material is removed at the electrode extraction portion. Further, in the configuration of the surface acoustic wave device of the present invention, the flattening pad that is not connected to either the surface acoustic wave element or the extraction electrode is on the piezoelectric substrate except the surface acoustic wave propagation region in the surface acoustic wave element. Is preferably provided in the. Further, in this case, it is preferable that the flattening pad is formed at a predetermined distance from the end surface of the surface acoustic wave device, and the extraction electrode is formed so as to be exposed at the end surface of the surface acoustic wave device. Further, in this case, it is preferable that the gap between the flattening pad and the extraction electrode is smaller than the minimum electrode width of the surface acoustic wave element.

A first surface acoustic wave device according to the present invention is also provided.
The method of manufacturing a piezoelectric substrate, wherein at least two surface acoustic wave elements and extraction electrodes connected to each of the surface acoustic wave elements are formed on the piezoelectric substrate, and the surface acoustic wave element and the extraction electrode are formed. An insulating thin film is formed on the surface of the surface acoustic wave device, and a cover material having a recess in a portion of the surface acoustic wave device facing the surface acoustic wave propagation region is directly bonded to the piezoelectric substrate, and the surface acoustic wave device is cut into individual pieces. After exposing the lead-out electrode to the end face, the external electrode is connected to the lead-out electrode exposed to the end face.

A second surface acoustic wave device according to the present invention is also provided.
The method of manufacturing a piezoelectric substrate, wherein at least two surface acoustic wave elements and extraction electrodes connected to each of the surface acoustic wave elements are formed on the piezoelectric substrate, and the surface acoustic wave element and the extraction electrode are formed. An insulating thin film is formed on the upper surface of the surface acoustic wave element, and a lid member having a concave portion in a portion of the surface acoustic wave element facing the surface acoustic wave propagation region is directly bonded to the piezoelectric substrate. It is provided with a configuration in which the extraction electrode is exposed by cutting, the external electrode is connected to the exposed extraction electrode, and then the surface acoustic wave element is cut into individual pieces.

The third surface acoustic wave device according to the present invention is also provided.
In the method for manufacturing the same, at least two surface acoustic wave devices and extraction electrodes connected to each are formed on a piezoelectric substrate,
An insulating thin film is formed on the piezoelectric substrate on which the surface acoustic wave element and the extraction electrode are formed, the thin film on the surface acoustic wave propagation region of the surface acoustic wave element is removed, and the thin film is patterned. A structure in which a lid member is directly bonded to the piezoelectric substrate, the surface acoustic wave element is cut into individual pieces to expose the extraction electrode on an end face, and then an external electrode is connected to the extraction electrode exposed on the end face It is a thing.

Further, a fourth surface acoustic wave device according to the present invention is provided.
In the method for manufacturing the same, at least two surface acoustic wave devices and extraction electrodes connected to each are formed on a piezoelectric substrate,
An insulating thin film is formed on the piezoelectric substrate on which the surface acoustic wave element and the extraction electrode are formed, the thin film on the surface acoustic wave propagation region of the surface acoustic wave element is removed, and the thin film is patterned. The lid material is directly bonded to the piezoelectric substrate, the bonded piezoelectric substrate and the lid material are half-cut to expose the extraction electrode, and an external electrode is connected to the exposed extraction electrode, and then the surface acoustic wave element is attached. It has a structure of cutting into individual pieces.

In the first to fourth structures of the method of the present invention, it is preferable that the thin film is mirror-polished before joining. In the first to fourth configurations of the method of the present invention, it is preferable to use a piezoelectric substrate having at least one surface mirror-polished.

In the first to fourth structures of the method of the present invention, it is preferable to use a lid member having a coefficient of thermal expansion substantially the same as that of the piezoelectric substrate. Further, in the first to fourth configurations of the method of the present invention, it is preferable to use a lid member having at least one surface mirror-polished.

Further, in the third or fourth structure of the method of the present invention, it is preferable to remove the thin film while leaving a predetermined film thickness. In addition, in the first to fourth configurations of the method of the present invention, it is preferable to remove the thin film in the electrode extraction portion.

In the first to fourth configurations of the method of the present invention, the surface acoustic wave device on the piezoelectric substrate is provided with a region other than the surface acoustic wave propagation region, and the surface acoustic wave device or the extraction electrode is provided with the surface acoustic wave device. It is preferable to form a flattening pad that is also not connected. Further, in this case, it is preferable that the flattening pad is formed at a predetermined distance from the region to be cut in the step of cutting the surface acoustic wave element into pieces, and the extraction electrode is formed in the region to be cut. preferable. Further, in this case, it is preferable that the gap between the flattening pad and the extraction electrode is formed smaller than the minimum electrode width of the surface acoustic wave element.

In the first to fourth structures of the method of the present invention, the extraction electrodes connected to the surface acoustic wave element are formed in a short-circuited state, and the short-circuited portion is cut when cut into individual pieces. It is preferably removed.

[0023]

According to the structure of the surface acoustic wave device of the present invention,
A surface acoustic wave device comprising at least a surface acoustic wave element on a piezoelectric substrate, and an extraction electrode connected to the surface acoustic wave element and extended to an end surface of the piezoelectric substrate.
A lid member directly joined to the piezoelectric substrate via an insulating thin film material existing on the surface acoustic wave element and the extraction electrode, and exposed at an end portion of a joining interface between the piezoelectric substrate and the lid member. Since it has an external electrode connected to the extraction electrode, the following operation can be achieved. That is, since the piezoelectric substrate having the surface acoustic wave element and the extraction electrode is directly joined to the lid member, no adhesive is required. As a result, the characteristics of the surface acoustic wave element are not changed by the gas released from the adhesive. Further, since the individual surface acoustic wave elements can be kept in a highly airtight and highly stable state, a surface acoustic wave device having high resistance to external thermal and mechanical shocks is realized.

Further, in the above-described structure of the surface acoustic wave device of the present invention, according to a preferable example in which the lid member has a concave portion at a portion of the surface acoustic wave element facing the surface acoustic wave propagation region, the lid material is provided on the piezoelectric substrate. The propagation of surface acoustic waves is not hindered.

Further, in the above-described structure of the surface acoustic wave device of the present invention, according to a preferable example in which the thin film material is completely removed only on the surface acoustic wave propagation region of the surface acoustic wave element, the recess is formed in the lid member. It is possible to propagate the surface acoustic wave on the piezoelectric substrate without forming the. Further, since the thin film material serves as a spacer material and the space between the lid material and the surface acoustic wave element is accurately ensured, the surface acoustic wave can be accurately propagated.

According to a preferred example of the structure of the surface acoustic wave device of the present invention, the thin film material is removed leaving a predetermined film thickness only on the surface acoustic wave propagation region of the surface acoustic wave element. The surface acoustic wave can be propagated on the piezoelectric substrate without forming the concave portion in the lid material, and the remaining thin film material allows the surface acoustic wave element
The DT electrode (comb-shaped electrode) is protected. It is also possible to improve the temperature characteristics of the piezoelectric substrate by providing a thin film material for compensating the temperature characteristics of the piezoelectric substrate on the surface acoustic wave element.
Further, in this case, according to a preferable example in which the predetermined film thickness is equal to or less than the propagation wavelength of the surface acoustic wave element, the propagation of the surface acoustic wave is not hindered (that is, the propagation loss due to the weight is minimized). In this state, the compensation of the temperature characteristic of the piezoelectric substrate and the protection of the IDT electrode are simultaneously achieved.

According to a preferred example of the structure of the surface acoustic wave device of the present invention, in which the thin film material is removed at the electrode extraction portion, the electrode extraction portion is exposed to the outside with a larger surface area. Therefore, the connection reliability when connecting the external electrodes is improved.

Further, in the structure of the surface acoustic wave device of the present invention, the flattening pad which is not connected to either the surface acoustic wave element or the extraction electrode is a piezoelectric element except for the surface acoustic wave propagation region in the surface acoustic wave element. According to the preferable example of being provided on the substrate, the step generated in the electrode portion when the thin film material is formed is reduced, and the piezoelectric substrate and the lid member can be bonded with high reliability. Also,
In this case, according to a preferred example in which the flattening pad is formed at a predetermined distance from the end surface of the surface acoustic wave device, and the extraction electrode is formed exposed on the end surface of the surface acoustic wave device. Even if the position for forming is slightly misaligned, the external electrode and the flattening pad are not erroneously connected, so that the connection reliability when connecting the external electrode is improved. Further, in this case, according to a preferable example in which the gap between the flattening pad and the take-out electrode is smaller than the minimum electrode width of the surface acoustic wave element, the flattening pad and the take-out electrode when a thin film material is coated. The amount of dents formed between and becomes small. Further, when discharge occurs between the electrodes due to the pyroelectricity of the piezoelectric substrate, discharge is preferentially started between the flattening pad and the extraction electrode, so that the IDT electrode of the surface acoustic wave element is Discharge is suppressed and deterioration of the IDT electrode is prevented.

According to the first aspect of the method of the present invention, at least two surface acoustic wave elements and extraction electrodes connected to each of the surface acoustic wave elements are formed on the piezoelectric substrate. An insulating thin film is formed on the piezoelectric substrate on which the surface acoustic wave element and the extraction electrode are formed, and a lid member having a concave portion at a portion of the surface acoustic wave element facing the surface acoustic wave propagation region is directly attached to the piezoelectric substrate. After joining, the surface acoustic wave element is cut into individual pieces to expose the extraction electrode on the end face, and then the external electrode is connected to the extraction electrode exposed on the end face, so that the following action is achieved. be able to. That is, since direct bonding is used to bond the piezoelectric substrate having the surface acoustic wave element and the extraction electrode to the lid member, no adhesive is required. As a result, the characteristics of the surface acoustic wave element are not changed by the gas released from the adhesive. In addition, since each surface acoustic wave element can be kept in a highly airtight and highly stable state, it can be handled as an assembly of surface acoustic wave devices having high resistance to external thermal and mechanical shocks. it can. Further, since a lid member having a recess is joined to a portion of the surface acoustic wave element facing the surface acoustic wave propagation region, a surface acoustic wave device that does not hinder the propagation of the surface acoustic wave on the piezoelectric substrate is provided. can get. Further, since the surface acoustic wave element group is handled as an assembly incorporated in a package, even if each surface acoustic wave element is miniaturized, the handling becomes easy. In addition, since it is possible to perform the process before the formation of the external electrodes in the final process in a batch process on a wafer-by-wafer basis, the manufacturing apparatus handling the same does not require precise positioning accuracy, and also has a transport mechanism for handling minute objects. It becomes unnecessary. As a result, the manufacturing process is simplified and the productivity is improved as compared with the conventional individual processing.

According to the second configuration of the method of the present invention, at least two surface acoustic wave elements and extraction electrodes connected to each of the surface acoustic wave elements are formed on the piezoelectric substrate. An insulating thin film is formed on the piezoelectric substrate on which the surface acoustic wave element and the extraction electrode are formed, and a lid member having a concave portion at a portion of the surface acoustic wave element facing the surface acoustic wave propagation region is directly attached to the piezoelectric substrate. After joining, the piezoelectric substrate and the lid member which were joined were half-cut to expose the extraction electrode, and after connecting the external electrode to the exposed extraction electrode, the surface acoustic wave element was cut into individual pieces. The following effects can be achieved. That is, since the final step of forming the external electrodes can be performed in a batch process for each wafer, the productivity is further improved as compared with the case of the first configuration of the method of the present invention.

According to the third aspect of the method of the present invention, at least two surface acoustic wave elements and extraction electrodes connected to each are formed on the piezoelectric substrate, and the surface acoustic wave elements and the extraction electrodes are connected to each other. An insulative thin film is formed on the formed piezoelectric substrate, the thin film on the surface acoustic wave propagation region of the surface acoustic wave element is removed, and the lid material is directly attached to the piezoelectric substrate through the patterned thin film. After joining, the surface acoustic wave element is cut into individual pieces to expose the extraction electrode on the end face, and then the external electrode is connected to the extraction electrode exposed on the end face, so that the following action is achieved. be able to. That is, since it is possible to propagate the surface acoustic wave on the piezoelectric substrate without forming a recess in the lid member, a material that is difficult to process can be used as the lid member. A wider range of choices. Further, the positional deviation between the concave portion and the surface acoustic wave propagation region at the time of joining, which is a problem when the concave portion is formed in the lid member, is eliminated. As a result, defective bonding and airtightness between the lid member and the piezoelectric substrate are reduced, and reliability after bonding is improved. In addition, since the process before the formation of the external electrodes in the final process can be performed in a batch process for each wafer, the productivity is improved as compared with the conventional individual process, as in the first configuration of the method of the present invention. .

According to the fourth aspect of the method of the present invention, at least two surface acoustic wave elements and extraction electrodes connected to each are formed on the piezoelectric substrate, and the surface acoustic wave elements and the extraction electrodes are connected to each other. An insulative thin film is formed on the formed piezoelectric substrate, the thin film on the surface acoustic wave propagation region of the surface acoustic wave element is removed, and the lid material is directly attached to the piezoelectric substrate through the patterned thin film. After joining, the piezoelectric substrate and the lid member which were joined were half-cut to expose the extraction electrode, and after connecting the external electrode to the exposed extraction electrode, the surface acoustic wave element was cut into individual pieces. The following effects can be achieved.
That is, since the final step of forming the external electrodes can be performed in a batch process for each wafer, the productivity is further improved as compared with the case of the third configuration of the method of the present invention.

In the first to fourth configurations of the method of the present invention, according to a preferred example in which the thin film is mirror-polished before bonding, the bonding surface is flattened to improve the adhesion between the piezoelectric substrate and the lid member. Since it can be improved, a surface acoustic wave device having higher airtightness can be obtained.

In the first to fourth structures of the method of the present invention, according to a preferred example in which at least one surface of the piezoelectric substrate is mirror-polished, a fine pattern of the surface acoustic wave element is formed by photolithography. It can be formed using a technique.

Further, in the first to fourth configurations of the method of the present invention, according to a preferable example in which the lid member having substantially the same coefficient of thermal expansion as that of the piezoelectric substrate is used, the piezoelectric substrate and the lid member are directly connected to each other. Heat treatment can be performed at higher temperatures to improve the strength of the bond.

Further, in the first to fourth structures of the method of the present invention, according to a preferred example in which at least one surface is mirror-polished, the adhesion between the piezoelectric substrate and the lid material is further improved. improves.

In the first to fourth configurations of the method of the present invention, the surface acoustic wave device on the piezoelectric substrate is provided with a region other than the surface acoustic wave propagation region, and the surface acoustic wave device and the extraction electrode are provided with the surface acoustic wave device. According to the preferable example of forming the flattening pad that is not connected, when the thin film material is formed, the step generated in the electrode portion is reduced, and the piezoelectric substrate and the lid member can be joined with high reliability. Further, in this case, it is preferable that the flattening pad is formed at a predetermined distance from the region to be cut in the step of cutting the surface acoustic wave element into pieces, and the extraction electrode is formed in the region to be cut. According to the example, by appropriately selecting the width of the dicing blade, it is possible to expose only the extraction electrode on the end face of the dicing blade. As a result, even if the position where the external electrode is formed is slightly deviated, the external electrode and the flattening pad are not erroneously connected, so that the connection reliability in connecting the external electrode is improved.

In the first to fourth structures of the method of the present invention, the extraction electrodes connected to the surface acoustic wave element are formed in a shorted state, and the shorted portions are removed when cut into individual pieces. According to the preferred example of
Even when heat treatment for improving the strength of direct bonding is performed, disconnection of the IDT electrode is reliably prevented, and the individual surface acoustic wave devices can be operated accurately after cutting. Also,
Even if a potential difference is generated on the electrode pattern, the potential is immediately equalized and the discharge between the IDT electrodes of the surface acoustic wave element is suppressed. Moreover, since the short line can be used as a reference dicing line in the cutting process, it is possible to accurately cut into individual pieces.

[0039]

EXAMPLES The present invention will be described in more detail below with reference to examples. <First Embodiment> First, a first embodiment of the present invention will be described. FIG. 1 is a process diagram showing a first embodiment of a method of manufacturing a surface acoustic wave device according to the present invention.

First, as shown in FIG. 1A, for example, L
A piezoelectric substrate 11 such as iTaO ₃ is prepared.
On top of this, a surface acoustic wave element group 12 composed of a plurality of surface acoustic wave elements using a metal such as Al as an electrode material, and an extraction electrode (input / output terminal 1
3 and the ground terminal 14). In this case, the extraction electrode is formed in the vicinity of the dicing lines S ₁ and S ₂ (FIG. 1 (d)), which are cutting lines in the cutting step described later. Since the surface acoustic wave element has a fine pattern formed by photolithography, it is necessary to use the piezoelectric substrate 11 whose surface is mirror-finished. In the case of a normal piezoelectric substrate for a surface acoustic wave element, a substrate having a mirror-finished surface is easily available, but when using a substrate other than that, it is necessary to polish the surface to a mirror surface in advance. is there.

The surface acoustic wave device usually has a pair of input / output terminals 13 and one or more ground terminals 14, respectively. In this embodiment, a four-terminal type surface acoustic wave element provided with two ground terminals 14 will be described as an example.

Next, as shown in FIG. 1B, an insulating thin film material 1 such as SiO _x is formed on the piezoelectric substrate 11.
5 to flatten the step on the surface of the piezoelectric substrate 11 on which the surface acoustic wave element group 12 is formed. When forming a thin film, an ordinary thin film forming apparatus such as vapor deposition, sputtering, or CVD may be used, but a thin film can be easily formed by spin coating or dipping a liquid coating material and heating and curing. can do. Although not shown, if the surface is lightly polished after coating the thin film material 15, the step created by the electrode can be further flattened.

When the surface of the piezoelectric substrate 11 is coated with the thin film material 15 as described above, even if the substrate surface comes into contact with a foreign substance, the IDT electrode (comb-shaped electrode) is unlikely to be damaged or peeled off. Since the electrodes are prevented from being damaged by such factors, the substrate can be easily handled in the subsequent steps. Further, since the space between the IDT electrodes is filled with an insulating film (thin film material 15), discharge between the electrodes that occurs when LiTaO ₃ having pyroelectricity is used as the piezoelectric substrate 11 as in the present embodiment, for example. It is difficult for the electrode to be disconnected, and the durability of the surface acoustic wave element is dramatically improved. Therefore, the breakage of the surface acoustic wave element in the subsequent process is suppressed to the minimum.

Next, as shown in FIG. 1C, both surfaces are mirror-polished and the lid member 16 made of LiTaO _{3 which} is the same as the piezoelectric substrate 11 is directly bonded to the piezoelectric substrate 11. In this case, a space is provided on the joint surface side of the lid member 16 so as not to obstruct the propagation of the surface acoustic wave on the piezoelectric substrate 11. This space may be formed by using a method such as ordinary etching, or may be formed by mechanically scraping. The shape of the space is arbitrary and is not limited to the quadrangle as shown in this embodiment.

The piezoelectric substrate 1 is also provided on the joint surface side of the lid member 16.
A thin film material 15 similar to that formed in 1 may be coated. By adopting such a configuration, even if the lid member 16 is not processed, only the layer of the thin film material 15 is selectively removed by etching or the like to form the concave portion, so that the propagation of the surface acoustic wave is not hindered. The space can be easily formed. When the lid member 16 is a material that can be easily processed, the lid member 16 may be directly processed without coating the thin film material 15. When the lid member 16 is a material that is difficult to process and mirror polishing is difficult, the thin film material 15
It is possible to easily form the space by mirror-polishing to form the recess. Therefore, the effect of coating the lid member 16 with the thin film material 15 is as follows.
Depending on the difficulty of processing the material of No. 6, the necessity of coating cannot be unconditionally determined. But,
When a substrate material having a relatively large surface roughness such as a ceramic substrate is used for the lid member 16, a coating material can be used to improve the surface roughness of the substrate.
In many cases, it is preferable to coat the lid member 16 with the thin film material 15.

In this embodiment, a transparent substrate whose both surfaces are mirror-polished is used as the lid member 16, but it is sufficient if at least the bonding surface is mirror-finished.
It does not need to be transparent. However, the transparent substrate has better visibility of the surface acoustic wave element after the lid member 16 is joined, and the cutting line is easier to determine in the cutting step described later. Therefore, a transparent substrate is used as the lid member 16. preferable.
On the other hand, the cutting line can be provided with a reference outside the substrate, and thus an opaque material can also be used.

In the present embodiment, the lid member 16 and the piezoelectric substrate 11 have the same coefficient of thermal expansion as LiT.
Although aO ₃ is used, it is not necessarily limited to this, and LiNbO ₃ , crystal, glass, ceramic material or the like can be used as the lid material 16. For example,
When LiNbO ₃ is used as the piezoelectric substrate 11, quartz can be used as the lid member 16. In this case, what is important is the matching of the thermal expansion coefficients of the piezoelectric substrate 11 and the lid member 16, and it is only necessary to select a material having a thermal expansion coefficient close to that of the piezoelectric substrate 11 for the lid member 16. If the lid member 16 is selected in consideration of the points, basically, the piezoelectric substrate 11 and the lid member 16 can be directly bonded by the following procedure.

First, the surfaces of the piezoelectric substrate 11 and the lid member 16 coated with the thin film material 15 are washed to remove foreign matters and organic substances. Next, the surfaces of the piezoelectric substrate 11 and the lid member 16 are subjected to hydrophilic treatment to form OH groups on the surfaces of the piezoelectric substrate 11 and the lid member 16. Next, the surface is rinsed with pure water, the pure water on the surface is dried by nitrogen blowing, and then the piezoelectric substrate 11 and the lid member 16 are brought into contact with each other. As a result, the piezoelectric substrate 11 and the lid member 16 are brought into close contact with each other by hydrogen bond between OH groups and van der Waals force acting between clean substrates. However, this bonding interface is not stable, and is easily separated by the degree of water penetration into the interface. Therefore, in order to improve the bonding strength between the lid member 16 and the piezoelectric substrate 11 and to make the bonding interface airtight, the contact temperature between the piezoelectric substrate 11 and the lid member 16 is 100 ° C. or higher (preferably 200 ° C.). Heat above (° C). By this heat treatment, the bonded interface is changed to a strong and chemically stable interface containing covalent bonds. Since this interface is bonded at the atomic level, it has good airtightness.

According to the above procedure, the piezoelectric substrate 11 and the lid member 1
By joining 6 and 6, each surface acoustic wave element is hermetically sealed, so that a stable surface acoustic wave device assembly 17 is realized in which the surface acoustic wave element is not affected by external impact and the environment of the outside air.

In order to improve the frequency stability of the surface acoustic wave element after joining, it is desirable that the joining be performed in vacuum or in an inert atmosphere such as nitrogen. However, even if the bonding is performed in the atmosphere, the surface acoustic wave element is a thin film material 1.
Since it is protected by 5, the electrode is less likely to be corroded and the structure is less likely to change over time. Therefore,
The above-mentioned joining may be performed in an atmosphere or a vacuum degree suitable for the stability required for the surface acoustic wave element, and this point is not particularly limited.

Finally, as shown in FIG.
Surface acoustic wave device assembly using a cutting device such as a saw
Dicing line showing the body 17 by a chain line in the figure
S₁, S ₂Cut along and divide into pieces. This cutting
Expose the input / output terminal 13 and the ground terminal 14 to the outside.
After letting it out, put a means such as vapor deposition at the position corresponding to them.
If the external electrode 18 is formed by using the
Child input / output terminal 13, earth terminal 14, and external electrode 18
And the surface acoustic wave device 19 is completed.

Surface acoustic wave device 19 produced in this example
Is a structure that does not use any adhesive or the like, so that gas or the like is hardly generated in the surface acoustic wave device. Therefore,
A surface acoustic wave device 19 that has a small influence of gas or the like on the surface acoustic wave element and has little change over time is realized. Also,
Since the process before the formation of the external electrode 18 in the final process is performed in a batch process for each wafer, the productivity is improved as compared with the conventional individual process. Further, the surface acoustic wave device 19 produced in this example is convenient for handling in wafer units because the internal surface acoustic wave element is always kept in a state of being shielded from disturbance in each production process.
It can be said that the structure is suitable for mass production because the yield is high through the steps from element formation to sealing.

In this embodiment, the input / output terminal 13, the ground terminal 14 and the external electrode 1 are divided into individual pieces.
However, the order is not necessarily limited to this order. As shown in FIG. 1E, the joined piezoelectric substrate 11 and lid member 16 may be half-cut, and the external electrodes 18 may be formed in the integrated state and then divided into individual pieces. If such a method is adopted, the final step of forming the external electrode 18 can be performed in a batch process for each wafer, and thus the productivity is further improved.

It is also possible to add a step of increasing the thickness of the external electrode 18 by performing plating treatment after forming the external electrode 18. Also in this case, the bonding interface is stable, and the plating solution or the like does not penetrate into the surface acoustic wave device 19 to attack the surface acoustic wave element.

In the present embodiment, the piezoelectric substrate 11
Alternatively, the thin film material 15 on the lid member 16 is subjected to polishing treatment before bonding, which flattens the bonding surface to improve the adhesion of the substrates to each other, and the surface acoustic wave having higher airtightness. This is to obtain the device 19. Therefore, when the step coverage with the thin film material 15 is sufficient and no step is generated, the thin film material 15 does not necessarily need to be subjected to the polishing treatment. That is, it is possible to handle the surface acoustic wave element and the lid member 16 integrally, regardless of the presence or absence of polishing treatment.

<Second Embodiment> Next, a second embodiment of the present invention will be described. 2 (a) is a schematic plan view showing a part of an assembly of the second embodiment of the surface acoustic wave device according to the present invention, FIG. 2 (b) is a sectional view of FIG. 2 (a), and FIG. c) is a schematic sectional view showing a second embodiment of the surface acoustic wave device according to the present invention.

The structure of the surface acoustic wave device of this embodiment is almost the same as that shown in the first embodiment, except for the following points. That is, in this embodiment, the patterning process of the thin film material 15 is introduced after the coating process of the thin film material 15 of the first embodiment. This patterning process will be briefly described with reference to FIG. Incidentally, FIG.
Although only one of the surface acoustic wave element group 12 formed on the piezoelectric substrate 11 is shown as a representative in FIGS. The same configuration is repeated on the left and right.

As shown in FIGS. 2A and 2B, the thin film material 15 coated on the piezoelectric substrate 11 on which the surface acoustic wave element group 12 is formed has a surface acoustic wave propagation region in each surface acoustic wave element. Only 21 has been completely removed. If such a configuration is adopted, the lid material 1 is formed on the thin film material 15.
When 6 is joined, the thin film material 15 serves as a spacer material to form a space 22 above the surface acoustic wave propagation region 21, and it is not necessary to form a recess in the lid material 16. as a result,
It is also possible to use a material that is difficult to process as the lid member 16,
The range of selection of materials for the lid member 16 is widened. Further, the positional deviation between the cover material space and the surface acoustic wave propagation region 21 at the time of joining, which is a problem when the recess is formed in the cover material 16, is eliminated. As a result, a defective joint between the lid member 16 and the piezoelectric substrate 11,
Airtightness is reduced and reliability after joining is improved. Also,
Also in this case, the extraction electrodes (the input / output terminal 13 and the ground terminal 14) corresponding to each surface acoustic wave element are formed in the vicinity of the dicing line which is a cutting line in the cutting process, and are divided into individual pieces. Thus, the extraction electrode can be exposed to the outside. Therefore, as shown in FIG. 2C, if the external electrode 18 is formed after being cut into individual pieces, the extraction electrode and the external electrode 18 of each surface acoustic wave element are formed.
Conduction is achieved with.

<Third Embodiment> Next, a third embodiment of the present invention will be described. 3 (a) is a schematic plan view showing a part of an assembly of a third embodiment of the surface acoustic wave device according to the present invention, FIG. 3 (b) is a sectional view of FIG. 3 (a), and FIG. c) is a schematic sectional view showing a third embodiment of the surface acoustic wave device according to the present invention.

The structure of the surface acoustic wave device of this embodiment is characterized by the patterning shape of the thin film material 15 as in the case of the second embodiment. Incidentally, FIG. 3 (a), (b)
In FIG. 2, only one of the surface acoustic wave element groups 12 formed on the piezoelectric substrate 11 is shown as a representative as in the case of FIG. The same configuration is repeated on the left and right.

As shown in FIGS. 3A and 3B, the thin film material 15 coated on the piezoelectric substrate 11 on which the surface acoustic wave element group 12 is formed has a surface acoustic wave propagation region in each surface acoustic wave element. 21 and the electrode lead-out portion 31 are completely removed. If such a configuration is adopted,
When the lid member 16 is bonded onto the thin film material 15, the thin film material 15 serves as a spacer material to reliably form the space 22 above the surface acoustic wave propagation region 21, and also to the electrode take-out portion 31. Two spaces are formed. This second space, when the assembly of the surface acoustic wave device is divided into individual pieces,
It will be exposed to the outside. Therefore, the electrode lead-out portion 31 is exposed to the outside with a larger surface area,
The connection reliability when connecting the external electrode 18 is improved. That is, the electrode can be reliably taken out from the surface acoustic wave element hermetically sealed.

Also in this case, the extraction electrodes (the input / output terminal 13 and the ground terminal 14) corresponding to the individual surface acoustic wave elements are formed in the vicinity of the dicing line which is the cutting line in the cutting process, The extraction electrode can be exposed to the outside by dividing into individual pieces. Therefore, as shown in FIG. 3C, if the external electrode 18 is formed after being cut into individual pieces, the extraction electrode of each surface acoustic wave element and the external electrode 18 can be electrically connected.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described. FIG. 4A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a fourth embodiment of the present invention, and FIG. 4B is a sectional view of FIG. c) is a schematic sectional view showing a fourth embodiment of the surface acoustic wave device according to the present invention. The surface acoustic wave device according to the present embodiment has the above-described second surface acoustic wave device.
It is manufactured by a process similar to that shown in the embodiment.

As shown in FIGS. 4A and 4B, the thin film material 15 coated on the piezoelectric substrate 11 on which the surface acoustic wave element group 12 is formed has a surface acoustic wave propagation region in each surface acoustic wave element. At 21, the film is removed leaving a predetermined film thickness. Here, it is preferable that the predetermined film thickness is equal to or less than the propagation wavelength of the surface acoustic wave element. If such a configuration is adopted, when the lid member 16 is bonded onto the thin film material 15, the thin film material 15 serves as a spacer material and the space 22 is formed above the surface acoustic wave propagation region 21. This point is the same as the second embodiment, but the difference from the second embodiment is that the thin film material 15 is slightly left on the surface acoustic wave propagation region 21. With such a configuration, the remaining thin film material 15 protects the IDT electrodes of the surface acoustic wave element group 12. As a result, it becomes easy to handle the surface acoustic wave device after the patterning step. Further, the thickness of the thin film material 15 can be controlled by removing the coated thin film material 15 in small amounts by using a method such as dry etching or wet etching. Therefore, it is formed on the piezoelectric substrate 11 by appropriately selecting the size of the film thickness and the material property (in particular, temperature coefficient of frequency) in consideration of the propagation wavelength of the surface acoustic wave and the material property of the piezoelectric substrate 11. It is possible to change the temperature characteristics of the surface acoustic wave element group 12 that is formed according to the purpose. For example, a SiO ₂ film formed by a CVD method is used as the thin film material 15, and Li is used as the piezoelectric substrate 11.
If NbO ₃ is used, since both exhibit frequency temperature coefficients having opposite signs, the temperature characteristics of the piezoelectric substrate (LiNbO ₃ substrate) 11 are improved. Such an effect can be obtained even in the structure in which the concave portion is formed in the lid member 16 and the thin film material 15 is not patterned at all as shown in the first embodiment, but in that case, It is necessary to set the thickness of the thin film material 15 appropriately and deposit it.

By adopting the configuration of this embodiment as described above, the effects of protecting the IDT electrodes of the surface acoustic wave element group 12 and improving the temperature characteristics of the piezoelectric substrate 11 can be obtained together.
Also in this case, the extraction electrodes (the input / output terminal 13 and the ground terminal 14) corresponding to each surface acoustic wave element are formed in the vicinity of the dicing line which is the cutting line in the cutting process, By dividing, the extraction electrode can be exposed to the outside. Therefore, FIG.
As shown in (c), the external electrode 18 after being cut into pieces
By forming, the electrical connection between the extraction electrode of each surface acoustic wave element and the external electrode 18 is achieved.

Further, similarly to the second embodiment, the electrode lead-out portion 31 may be provided with a space as shown in FIG. According to the configurations shown in the first to fourth embodiments, when each surface acoustic wave element is divided into individual pieces, the surface acoustic wave elements are fixed to the conductor pattern on the printed circuit board by means of soldering or the like. Although a surface acoustic wave device in a state where the above can be obtained can be obtained, the reliability and mass productivity of the assembly of surface acoustic wave devices can be further improved by adopting the configuration of the following fifth embodiment.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described. FIG. 6A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a fifth embodiment of the present invention, and FIG. 6B is a sectional view taken along line AA of FIG. 6A. is there.

As shown in FIGS. 6A and 6B, in the surface acoustic wave device of this embodiment, on the piezoelectric substrate 11,
Surface acoustic wave element group 12, input / output terminal 13, earth terminal 1
4, a flattening pad 51 is formed. Here, the flattening pad 51 is not connected to any terminal of the surface acoustic wave element group 12, and is formed in an area excluding the surface acoustic wave propagation area 21 in each surface acoustic wave element. By adopting such a configuration, when the thin film material 15 is coated, the step generated in the electrode portion becomes small, and the piezoelectric substrate 11 and the lid member 16 can be bonded with high reliability.

As shown in FIG. 6B, even when the thin film material 15 is subjected to a polishing process of a very thin layer in order to further improve the reliability of the bonding, the polishing cloth 52 for polishing and the substrate are not in contact with each other. Since it is performed uniformly, the accuracy of polishing is improved, and the bonding with high airtightness becomes possible.

Further, if the structure as in the following sixth embodiment is adopted, the reliability when connecting the external electrodes is further improved. <Sixth Embodiment> Next, a sixth embodiment of the present invention will be described. FIG. 7A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a sixth embodiment of the present invention, FIG.
FIG. 7B is a schematic plan view showing a sixth embodiment of the surface acoustic wave device according to the present invention, and FIG. 7C is a schematic perspective view showing the sixth embodiment of the surface acoustic wave device according to the present invention. is there.

As shown in FIG. 7A, the input / output terminal 13 and the ground terminal 14 which are adjacent to each other are formed in the vicinity of the dicing lines S ₁ and S ₂ which are cutting lines in the cutting process. On the other hand, the flattening pad 51 is formed at a predetermined distance from the dicing lines S ₁ and S ₂ .

The above pattern is formed on the piezoelectric substrate 11, and the entire surface is coated with the thin film material 15. After that, the lid member 16 is directly bonded to the piezoelectric substrate 11 by the procedure described above, and cut out at the dicing lines S ₁ and S ₂ . As a result, each surface acoustic wave element is divided into pieces with a width proportional to the width of the dicing blade. Therefore, by properly selecting the width of the dicing blade,
As shown in (b) and (c), the input / output terminal 1 is provided on the end face.
An individual piece in which only 3 and the ground terminal 14 are exposed is obtained.
As a result, even if the position where the external electrode is formed is slightly deviated, the external electrode and the flattening pad 51 are not erroneously connected, so that the reliability in connecting the external electrode is improved.

Further, if the structure of the following seventh embodiment is adopted, the yield in manufacturing the surface acoustic wave device is improved. <Seventh Embodiment> Next, a seventh embodiment of the present invention will be described. FIG. 8 is a schematic plan view showing a seventh embodiment of the surface acoustic wave device according to the present invention.

As shown in FIG. 8, the gap d ₁ between the flattening pad 51 and each extraction electrode (the input / output terminal 13 and the ground terminal 14) is the interelectrode gap d ₂ in the surface acoustic wave element group 12. Is smaller than the above, and is the smallest of all electrode patterns. If such a configuration is adopted, the amount of dents formed between the flattening pad 51 and the extraction electrode when the thin film material is coated is reduced. Further, when discharge between the electrodes due to the pyroelectricity of the piezoelectric substrate occurs, discharge is preferentially started at the minimum gap d ₁ , so that the IDT in the surface acoustic wave element group 12 is
Discharge between the electrodes can be suppressed. As a result, the yield in manufacturing the surface acoustic wave device is improved.

Further, if the structure of the following eighth embodiment is adopted, the discharge between the IDT electrodes can be suppressed to the minimum. <Eighth Embodiment> Next, an eighth embodiment of the present invention will be described. FIG. 9 is a schematic plan view showing a part of an aggregate of an eighth embodiment of the surface acoustic wave device according to the present invention.

As shown in FIG. 9, in the electrode pattern of this embodiment, each extraction electrode (the input / output terminal 13 and the ground terminal 14) is short-circuited. If such a configuration is adopted, even if a potential difference is generated on the electrode pattern, the potential is immediately equalized, and the discharge between the IDT electrodes can be suppressed to the minimum. Moreover, since the short line can be used as a reference dicing line in the cutting step, each surface acoustic wave element is accurately cut out, and the cut surface acoustic wave device has the above-mentioned characteristics. It will be reliable.

In the above first to eighth embodiments,
Although a four-terminal surface acoustic wave element has been described as an example, the present invention is not necessarily limited to this configuration and can be designed according to desired characteristics.

[0078]

As described above, according to the surface acoustic wave device of the present invention, the following effects can be obtained. That is, since the piezoelectric substrate having the surface acoustic wave element and the extraction electrode is directly joined to the lid member, no adhesive is required. As a result, the characteristics of the surface acoustic wave element are not changed by the gas released from the adhesive. Further, since the individual surface acoustic wave elements can be kept in a highly airtight and highly stable state, a surface acoustic wave device having high resistance to external thermal and mechanical shocks is realized.

Further, the first surface acoustic wave device according to the present invention
According to the manufacturing method of, the following effects can be obtained. That is, since direct bonding is used to bond the piezoelectric substrate having the surface acoustic wave element and the extraction electrode to the lid member, no adhesive is required. As a result, the characteristics of the surface acoustic wave element are not changed by the gas released from the adhesive. In addition, since each surface acoustic wave element can be kept in a highly airtight and highly stable state, it can be handled as an assembly of surface acoustic wave devices having high resistance to external thermal and mechanical shocks. it can. Further, since a lid member having a recess is joined to a portion of the surface acoustic wave element facing the surface acoustic wave propagation region, a surface acoustic wave device that does not hinder the propagation of the surface acoustic wave on the piezoelectric substrate is provided. can get. Further, since the surface acoustic wave element group is handled as an assembly incorporated in a package, even if each surface acoustic wave element is miniaturized, the handling becomes easy. In addition, since it is possible to perform the process before the formation of the external electrodes in the final process in a batch process on a wafer-by-wafer basis, the manufacturing apparatus handling the same does not require precise positioning accuracy, and also has a transport mechanism for handling minute objects. It becomes unnecessary. As a result, the manufacturing process is simplified and the productivity is improved as compared with the conventional individual processing.

Further, the second surface acoustic wave device according to the present invention
According to the manufacturing method of, the following effects can be obtained. That is, since the external electrodes in the final step can be formed in a batch process for each wafer, the first method of the present invention can be performed.
The productivity is further improved as compared with the case of the above configuration.

The third surface acoustic wave device according to the present invention is also provided.
According to the manufacturing method of, the following effects can be obtained. That is, since it is possible to propagate the surface acoustic wave on the piezoelectric substrate without forming a recess in the lid member, a material that is difficult to process can be used as the lid member. A wider range of choices. Further, the positional deviation between the concave portion and the surface acoustic wave propagation region at the time of joining, which is a problem when the concave portion is formed in the lid member, is eliminated. As a result, defective bonding and airtightness between the lid member and the piezoelectric substrate are reduced, and reliability after bonding is improved. In addition, since the process before the formation of the external electrodes in the final process can be performed in a batch process for each wafer, the productivity is improved as compared with the conventional individual process, as in the first configuration of the method of the present invention. .

The fourth surface acoustic wave device according to the present invention is also provided.
According to the manufacturing method of, the following effects can be obtained. That is, since the external electrodes in the final step can be formed in a batch process on a wafer basis, the third method of the present invention can be performed.
The productivity is further improved as compared with the case of the above configuration.

[Brief description of drawings]

FIG. 1 is a first method of manufacturing a surface acoustic wave device according to the present invention.
FIG. 4 is a process chart showing an example of the method.

2A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a second embodiment of the present invention, FIG. 2B is a sectional view of FIG. 2A, and FIG. It is a schematic sectional drawing which shows the 2nd Example of the surface acoustic wave device which concerns on invention.

3A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a third embodiment of the present invention, FIG. 3B is a sectional view of FIG. 3A, and FIG. It is a schematic sectional drawing which shows the 3rd Example of the surface acoustic wave device which concerns on invention.

4A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a fourth embodiment of the present invention, FIG. 4B is a sectional view of FIG. 4A, and FIG. It is a schematic sectional drawing which shows the 4th Example of the surface acoustic wave device which concerns on invention.

FIG. 5A is a schematic plan view showing a part of another example of the assembly of the surface acoustic wave device according to the fourth embodiment of the present invention;
(B) is sectional drawing of (a), (c) is a schematic sectional drawing which shows the other example of the 4th Example of the surface acoustic wave apparatus which concerns on this invention.

6A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a fifth embodiment of the present invention, and FIG. 6B is a sectional view taken along line AA of FIG.

7A is a schematic plan view showing a part of an assembly of a surface acoustic wave device according to a sixth embodiment of the present invention, and FIG. 7B is a sixth surface acoustic wave device according to the present invention. FIG. 6 is a schematic plan view showing an embodiment, and FIG. 6 (c) is a schematic perspective view showing a sixth embodiment of the surface acoustic wave device according to the present invention.

FIG. 8 is a schematic plan view showing a seventh embodiment of the surface acoustic wave device according to the present invention.

FIG. 9 is a schematic plan view showing a part of an aggregate of an eighth embodiment of the surface acoustic wave device according to the present invention.

10A is a schematic cross-sectional view showing a surface acoustic wave device according to a conventional technique, and FIG. 10B is a schematic cross-sectional view showing another example of the surface acoustic wave device according to the conventional technique.

[Explanation of symbols]

 11 piezoelectric substrate 12 surface acoustic wave element group 13 input / output terminal 14 ground terminal 15 thin film material 16 lid material 17 surface acoustic wave device assembly 18 external electrode 19 surface acoustic wave device 21 surface acoustic wave propagation region 22 space 31 electrode extraction part 51 Pad for flattening

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Eda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (23)

[Claims] 1. A surface acoustic wave device comprising at least a surface acoustic wave element on a piezoelectric substrate, and an extraction electrode connected to the surface acoustic wave element and extended to an end surface of the piezoelectric substrate. A cover material directly bonded to the piezoelectric substrate via an insulating thin film material existing on the surface acoustic wave element and the extraction electrode, and the extraction exposed at an end portion of a bonding interface between the piezoelectric substrate and the cover material A surface acoustic wave device comprising: an external electrode connected to the electrode. 2. The surface acoustic wave device according to claim 1, wherein the lid member has a concave portion in a portion of the surface acoustic wave element facing the surface acoustic wave propagation region. 3. The thin film material is completely removed only on the surface acoustic wave propagation region of the surface acoustic wave device.
The surface acoustic wave device according to. 4. The surface acoustic wave device according to claim 1, wherein the thin film material is removed only on the surface acoustic wave propagation region of the surface acoustic wave element, leaving a predetermined film thickness. 5. The surface acoustic wave device according to claim 4, wherein the predetermined film thickness is equal to or less than the propagation wavelength of the surface acoustic wave element. 6. The surface acoustic wave device according to claim 1, wherein the thin film material is removed at the electrode extraction portion. 7. The flattening pad that is not connected to either the surface acoustic wave element or the extraction electrode is provided on the piezoelectric substrate except the surface acoustic wave propagation region of the surface acoustic wave element. Surface acoustic wave device. 8. The elastic member according to claim 7, wherein the flattening pad is formed at a predetermined distance from the end surface of the surface acoustic wave device, and the extraction electrode is formed so as to be exposed at the end surface of the surface acoustic wave device. Surface wave device. 9. The surface acoustic wave device according to claim 7, wherein the gap between the flattening pad and the extraction electrode is smaller than the minimum electrode width of the surface acoustic wave element. 10. A piezoelectric substrate having at least two surface acoustic wave elements and extraction electrodes connected to each of the surface acoustic wave elements formed on the piezoelectric substrate, and the surface acoustic wave elements and the extraction electrodes formed on the piezoelectric substrate. Form an insulating thin film on top,
A lid member having a concave portion in a portion facing the surface acoustic wave propagation region of the surface acoustic wave element was directly bonded to the piezoelectric substrate, and the surface acoustic wave element was cut into individual pieces to expose the extraction electrode on an end surface. After that, a method of manufacturing a surface acoustic wave device, in which an external electrode is connected to the extraction electrode exposed on the end face. 11. A piezoelectric substrate in which at least two surface acoustic wave elements and extraction electrodes connected to each of the surface acoustic wave elements are formed on a piezoelectric substrate, and the surface acoustic wave elements and the extraction electrodes are formed. Form an insulating thin film on top,
A lid member having a concave portion in a portion facing the surface acoustic wave propagation region in the surface acoustic wave element is directly joined to the piezoelectric substrate, and the joined piezoelectric substrate and lid member are half-cut to expose the extraction electrode, A method of manufacturing a surface acoustic wave device, which comprises connecting an external electrode to the exposed extraction electrode and then cutting the surface acoustic wave element into individual pieces. 12. A piezoelectric substrate having at least two surface acoustic wave elements and extraction electrodes connected thereto, and an insulating thin film formed on the piezoelectric substrate having the surface acoustic wave elements and the extraction electrodes formed thereon. Then, the thin film on the surface acoustic wave propagation region of the surface acoustic wave element is removed, the lid material is directly bonded to the piezoelectric substrate through the patterned thin film, and the surface acoustic wave element is cut into individual pieces. A method for manufacturing a surface acoustic wave device, wherein the extraction electrode is exposed to an end face and then an external electrode is connected to the extraction electrode exposed to the end face. 13. A piezoelectric substrate having at least two surface acoustic wave elements and extraction electrodes connected to the respective surface acoustic wave elements, and an insulating thin film formed on the piezoelectric substrate having the surface acoustic wave elements and the extraction electrodes formed thereon. Then, the thin film on the surface acoustic wave propagation region of the surface acoustic wave element is removed, the lid material is directly bonded to the piezoelectric substrate through the patterned thin film, and the bonded piezoelectric substrate and lid material are half-bonded. A method of manufacturing a surface acoustic wave device, which comprises cutting to expose the extraction electrode, connecting an external electrode to the exposed extraction electrode, and then cutting the surface acoustic wave element into individual pieces. 14. The thin film is mirror-polished before bonding.
The method for manufacturing a surface acoustic wave device according to any one of 0 to 13. 15. The method of manufacturing a surface acoustic wave device according to claim 10, wherein a piezoelectric substrate having at least one surface mirror-polished is used. 16. The method for manufacturing a surface acoustic wave device according to claim 10, wherein a lid member having a coefficient of thermal expansion substantially the same as that of the piezoelectric substrate is used. 17. The method of manufacturing a surface acoustic wave device according to claim 10, wherein a lid member having at least one surface mirror-polished is used. 18. The method of manufacturing a surface acoustic wave device according to claim 12, wherein the thin film is removed while leaving a predetermined film thickness. 19. The method for manufacturing a surface acoustic wave device according to claim 10, wherein the thin film in the electrode extraction portion is removed. 20. A planarization pad which is not connected to either the surface acoustic wave device or the extraction electrode is formed in a region of the surface acoustic wave device on the piezoelectric substrate excluding the surface acoustic wave propagation region. A method of manufacturing a surface acoustic wave device according to any one of 1. 21. A flattening pad is formed at a predetermined distance from a region to be cut in the step of cutting the surface acoustic wave element into individual pieces, and an extraction electrode is formed in the cut region. 21. The method for manufacturing the surface acoustic wave device according to 20. 22. The method of manufacturing a surface acoustic wave device according to claim 20, wherein the gap between the flattening pad and the extraction electrode is formed smaller than the minimum electrode width of the surface acoustic wave element. 23. The elastic surface according to claim 10, wherein the extraction electrodes connected to the surface acoustic wave element are formed in a state where they are short-circuited, and the short-circuited portions are removed when the electrodes are cut into individual pieces. Wave device manufacturing method.