KR100798599B1 - Surface acoustic wave device and manufacturing method thereof - Google Patents

Abstract

The present invention realizes a small and thin surface acoustic wave device.

The surface acoustic wave device 10 includes an IDT electrode 50 formed on the main surface of the piezoelectric substrate 20, extraction electrodes 45 and 46 drawn out from the IDT electrode 50, and an outer circumference of the main surface of the piezoelectric substrate 20. A surface acoustic wave chip 15 having a metal junction portion 40 formed along the surface thereof, a connecting electrode 73 and 74 made of an insulating material and connected to the extraction electrodes 45 and 46, and external electrodes 77 and 78; And the cover substrate 30 having the through electrodes 75 and 76 connecting the connection electrodes 73 and 74 to the external electrodes 77 and 78, and the surface acoustic wave chip 15 and the cover substrate 30 are bonded to each other. Inside the space to be formed, the IDT electrode 50 and the extraction electrodes 45 and 46 are hermetically sealed, and even if the piezoelectric substrate 20 or the cover substrate 30 deforms, the cover substrate 30 remains the IDT electrode 50. An auxiliary portion 70 having a height that does not come in contact with is characterized in that formed on the main surface of the piezoelectric substrate 20.

Description

Surface acoustic wave device and its manufacturing method {SURFACE ACOUSTIC WAVE DEVICE AND MANUFACTURING METHOD THEREOF}

BRIEF DESCRIPTION OF THE DRAWINGS The surface acoustic wave device which concerns on Embodiment 1 of this invention, a is its top view, b is sectional drawing which shows the A-A cutting surface of a.

2 is a plan view of a surface acoustic wave chip according to Embodiment 1 of the present invention.

3 is a plan view of a cover substrate according to Embodiment 1 of the invention.

4A to 4E are cross-sectional views showing examples of the manufacturing steps of the surface acoustic wave device according to the first embodiment of the present invention.

5 is a plan view showing a surface acoustic wave chip according to Modification Example 1 of First Embodiment of the invention;

Fig. 6 is a plan view showing a surface acoustic wave chip according to Modification 2 of Embodiment 1 of the present invention.

Fig. 7 shows a surface acoustic wave chip according to Embodiment 2 of the present invention, a is a plan view thereof, and b is a sectional view showing a B-B cutting plane of a.

<Description of the symbols for the main parts of the drawings>

10 surface acoustic wave device, 15 surface acoustic wave chip

20: piezoelectric substrate, 30: cover substrate

40: metal junction part, 45, 46: extraction electrode

50: IDT electrode, 60, 61: reflector

70: auxiliary part, 73, 74: connection electrode

77, 78: external electrode.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave device and a method of manufacturing the same, and more particularly, to a surface acoustic wave device having an auxiliary portion for preventing contact between an IDT electrode and a cover substrate and a method of manufacturing the same.

Conventionally, a surface acoustic wave chip is composed of an IDT electrode, an extraction electrode, and an anode bonding portion arranged to surround these on a piezoelectric substrate, and an insulating cover substrate forms voids and through holes in the glass plate, and through holes and peripheral portions thereof. A surface acoustic wave composed of an external electrode provided and a printed electrode provided along the external electrode, wherein the extraction electrode of the surface acoustic wave chip is bonded to the external electrode of the cover substrate, and the anode joint is bonded to the cover substrate to seal the IDT electrode. It is known to be a device.

The cover substrate, the surface acoustic wave chip having the thickness of the extraction electrode of the surface acoustic wave chip and the positive electrode junction portion increased by about 3 µm from the above film thickness without providing the air gap in the cover substrate described above. It is proposed that the surface acoustic wave device is provided with a gap between the IDT electrode and the cover substrate by the electrode and the anode junction (for example, Japanese Patent Laid-Open No. 8-213874 (pages 3 to 5, FIGS. 1, 3, 8). ) Reference).

In the structure in which a space | gap is provided in the cover board | substrate of Unexamined-Japanese-Patent No. 8-213874, the space | gap part with which an IDT electrode and a cover board | substrate do not contact even if it is distorted by external force is provided in the cover board | substrate. Therefore, in order to ensure the strength of a cover substrate, the whole cover substrate must be thickened, and it is a structure which is disadvantageous for thinning a surface acoustic wave device.

In addition, in a structure in which the gap between the IDT electrode and the cover substrate is secured by making the extraction electrode and the anode junction thick, it is considered that the cover substrate and the IDT electrode are in contact with each other, for example, when distortion occurs in the central portion of the cover substrate. Moreover, in this structure, since the extraction electrode is arrange | positioned in the advancing direction of the surface wave of an IDT electrode, the reflector or the reflection wall provided in a general surface acoustic wave chip cannot be arrange | positioned, and it is predicted that an accurate resonance frequency will not be obtained. do.

Summary of the Invention An object of the present invention is to solve the above-described problems, and to realize a small and thin surface acoustic wave device, a surface acoustic wave device having a structure in which the IDT electrode and the cover substrate do not come into contact with each other even if the piezoelectric substrate and the cover substrate are distorted. It is to provide a manufacturing method.

The surface acoustic wave device of the present invention includes an surface acoustic wave chip having an IDT electrode formed on a main surface of a piezoelectric substrate, an extraction electrode drawn out from the IDT electrode, a metal joint formed along the outer circumference of the main surface of the piezoelectric substrate, and an insulating material. A cover substrate having a connection electrode connected to the extraction electrode provided on one main surface, an external electrode provided on the other main surface, a through electrode connecting the connection electrode and the external electrode, and the Even if the IDT electrode and the extraction electrode are hermetically sealed in a space formed by joining the surface acoustic wave chip and the cover substrate at the metal bonding portion, and the piezoelectric substrate or the cover substrate is deformed in the space, An auxiliary portion having a height such that the cover substrate does not contact the IDT electrode, the main surface of the piezoelectric substrate It characterized in that it is formed.

According to the present invention, the IDT electrode and the extraction electrode are provided in a space where the airtight seal is sealed, and an auxiliary portion having a height such that the cover substrate does not contact the IDT electrode even if the piezoelectric substrate or the cover substrate is deformed in the space. Doing. Since the auxiliary portion is set lower than the height of the space and higher than the thickness of the IDT electrode, it is not necessary to set the height of the space as high as the margin so as not to contact the cover substrate and the IDT electrode, and also the strength of the cover substrate. It is not necessary to thicken the cover substrate in order to secure the structure, and it is possible to realize a thin surface acoustic wave device and to prevent the resonance frequency from becoming unstable due to the contact between the IDT electrode and the cover substrate.

In addition, since the auxiliary part can be disposed in the clearance space of the IDT electrode and the extraction electrode in the space, it is not necessary to increase the plane size of the piezoelectric substrate and the cover substrate, and can realize a small surface acoustic wave device.

In addition, the auxiliary portion is preferably a metal film formed along the longitudinal direction of the IDT electrode at a position spaced apart near the IDT electrode.

Thus, by arranging the auxiliary portion made of the metal film in the vicinity of the IDT electrode and along the IDT electrode, miniaturization and thinning can be realized while preventing contact between the cover substrate and the IDT electrode. In addition, although it demonstrates in embodiment mentioned later in detail, since an auxiliary part is formed with a metal film, it can form easily in the formation process of an IDT electrode or an extraction electrode easily.

When the extraction electrode is provided in the range of the formation area of the said IDT electrode along the longitudinal direction of the said IDT electrode, when the said piezoelectric board | substrate and the said cover substrate were joined, it is formed in the same thickness as the height of the said space, and the said auxiliary | assistant part It is preferable to also use.

By forming the extraction electrode in this way, in addition to the connection function with the original external electrode and having the function as an auxiliary part, the above-described effect can be obtained without forming the auxiliary part again. Since this extraction electrode can be formed in the magnitude | size of the plane and empty space area | region provided in order to have a function as an original extraction electrode, the size of a surface acoustic wave device does not become large.

Moreover, it is preferable that the said auxiliary part is formed in the surface of the bus bar which comprises the said IDT electrode.

The bus bar constitutes the IDT electrode together with the crossover electrode, but the arrangement of the auxiliary portion on the surface of the bus bar does not affect the resonance frequency. Therefore, when the auxiliary portion is disposed on the surface of the bus bar, the auxiliary portion is disposed at the position closest to the IDT electrode. Therefore, even if the height of the auxiliary portion is reduced, the object of the present invention can be achieved. In addition, the occupied area of the auxiliary part is also within the range of the IDT electrode and does not require a dedicated space for the auxiliary part.

Moreover, the manufacturing method of the surface acoustic wave device of this invention has an IDT electrode provided in the main surface of a piezoelectric substrate, the extraction electrode drawn out from the said IDT electrode, the metal junction part formed along the outer periphery of the main surface of the said piezoelectric substrate, and an auxiliary part. Forming a surface acoustic wave chip, a connecting electrode connected to the extraction electrode provided on one main surface, an external electrode provided on the other main surface, and a through electrode connecting the connecting electrode and the external electrode. A step of forming a cover substrate to have, a step of joining the surface acoustic wave chip and the cover substrate in the metal bonding portion, and a step of hermetically sealing a through electrode, wherein the auxiliary portion includes the piezoelectric substrate or the cover substrate. The cover substrate may be formed at a height such that the cover substrate does not contact the IDT electrode even if deformed.

The above-mentioned auxiliary part can be formed in the range of the formation process of an extraction electrode or IDT electrode, and can be manufactured without enormous process increase by installing an auxiliary part.

In addition, since the extraction electrode is connected to the external electrode via the through electrode provided on the cover substrate, the airtightness of the space can be maintained because the junction electrode is not crossed.

In the forming step of the auxiliary part, in the forming step of the extraction electrode or the metal bonding part, after the first layer is formed of the same material as the extraction electrode at a position spaced apart from the IDT electrode and the extraction electrode, It is preferable to include the step of laminating the auxiliary portion to a predetermined thickness.

Here, the auxiliary portion is formed by a metal film of the same material that is electrically independent of each of the extraction electrode or the metal bonding portion.

Therefore, by forming the auxiliary part in the step of forming the extraction electrode or the metal junction part, and adding the step of making the predetermined thickness again, one or more layers of metal films are further laminated to correspond to the required thickness of the auxiliary part. Can be formed.

Moreover, in the formation process of the said extraction electrode, when taking out the said extraction electrode in the range of the formation area of the said IDT electrode substantially along the longitudinal direction of the said IDT electrode, when taking out the said surface acoustic wave chip and the said cover substrate, it is taken out. Preferably, the electrode is formed to a thickness corresponding to the inner surface of the cover substrate.

In this case, since the extraction electrode is formed to have a thickness in contact with the cover substrate and follows the IDT electrode, the height of the inner surface of the cover substrate can be regulated by the extraction electrode. That is, this extraction electrode has the function of the above-mentioned auxiliary part. Therefore, the process of forming an auxiliary electrode becomes unnecessary, and it becomes possible to simplify the manufacturing process of a surface acoustic wave chip.

Further, in the step of forming the auxiliary portion, in the step of forming the IDT electrode, a step of forming the first layer near the IDT electrode in the same process as the IDT electrode and then laminating the auxiliary portion to a predetermined thickness. It is preferable to include.

In this way, the first layer of the auxiliary portion is formed of the same material and the same thickness as the IDT electrode, and is laminated to have a predetermined thickness to form the auxiliary portion, so that the auxiliary portion is formed to be thicker than the IDT electrode in the vicinity of the IDT electrode. Therefore, contact with a cover substrate can be reliably prevented.

In addition, it is preferable to form the auxiliary part in a predetermined thickness in an auxiliary part forming step separate from the step of forming the IDT electrode and the step of forming the extraction electrode.

In this way, the auxiliary portion can be formed by arbitrarily selecting a material and a manufacturing process different from the IDT electrode or the extraction electrode.

The auxiliary portion is preferably laminated on the surface of the bus bar constituting the IDT electrode at a predetermined thickness with the same material as the IDT electrode after the step of forming the IDT electrode.

In this way, when the auxiliary portion is disposed on the surface of the bus bar, the auxiliary portion is disposed at the position closest to the IDT electrode. Therefore, even if the height of the auxiliary portion is reduced, the object of the present invention can be achieved. The area occupied by the auxiliary part is also within the range of the IDT electrode.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. In the present embodiment, the surface acoustic wave device is exemplified as a preferred embodiment of the resonator to which the present invention is applied.

1 to 4 show a structure and a manufacturing method of the surface acoustic wave device according to Embodiment 1 of the present invention, and FIG. 5 shows Modification Example 1 of Embodiment 1, and FIG. 6 Modification Examples 2 and 7 of Embodiment 1 Illustrates Embodiment 2.

Embodiment 1

1 to 4 show the structure and the manufacturing method of the surface acoustic wave device according to the first embodiment.

1 shows a surface acoustic wave device 10 according to the present embodiment, where a is a plan view thereof, and b is a sectional view showing an A-A cut plane of a. 2 is a plan view of the surface acoustic wave chip 15, and FIG. 3 is a plan view of the cover substrate 30. 1, 2, and 3, the surface acoustic wave device 10 includes a surface acoustic wave chip 15 having an IDT electrode 50 (Interdigital Transducer), and a cover substrate 30 laminated and directly bonded to an upper surface thereof. It consists of.

The surface acoustic wave chip 15 is composed of a rectangular piezoelectric substrate 20, and has an IDT electrode 50 composed of a pair of crossover electrodes and respective bus bars 51 and 52 at approximately the center of the surface 22 as a main surface thereof. ) Are formed, and reflectors 60 and 61 are formed at both ends of the longitudinal direction (the direction of the surface wave travel). In addition, the detailed shape of IDT electrode 50 and the reflector 60, 61 is abbreviate | omitted.

One side of the pair of crossing electrodes described above, the lead electrode 45A is drawn out from the bus bar 51 vertically, and the extraction electrode 45 is formed along the longitudinal direction of the piezoelectric substrate 20 at the end thereof. have. On the other side of the crossover electrode, the lead electrode 46A is drawn out from the bus bar 52 in the reverse direction of the lead electrode 45A, and at the end thereof, the extraction electrode 46 is positioned at a position opposite to the extraction electrode 45. Formed. Moreover, the metal junction part 40 is formed in the periphery of the outer periphery of the surface 22 of the piezoelectric substrate 20 over the whole perimeter.

In addition, the IDT electrode 50 and the reflectors 60 and 61 are spaced apart from each other along the lengthwise sides of the IDT electrode 50 and the reflectors 60 and 61 (that is, when the longitudinal direction is the traveling direction of the surface wave). On both sides in the width direction, a plurality of island-shaped auxiliary portions 70 are formed. The auxiliary part 70 is formed thicker than the thickness of the IDT electrode 50 so as not to contact the back surface 33 of the cover substrate 30. That is, the thickness of the auxiliary part 70 is equal to the IDT electrode 50 (including the reflectors 60 and 61) even when the piezoelectric substrate 20 (elastic surface wave chip 15) or the cover substrate 30 is distorted. It is suitably set in the range which the back surface 33 of the cover substrate 30 does not contact.

On the other hand, in Fig. 2, six auxiliary portions 70 are arranged on each side of the IDT electrode 50 and the reflectors 60 and 61, respectively, but the number of the auxiliary portions 70 is not limited to this and can be increased or decreased from five. have. In addition, the arrangement position is not limited to FIG. 2, but can be arranged at a position appropriately selected within a range that achieves the object of the present invention. Therefore, it can also arrange | position to one of the IDT electrode 50 and the reflector 60,61.

In the present embodiment, the piezoelectric substrate 20 is formed of quartz, but other piezoelectric materials such as lithium tantalate and lithium niobate may be employed. The IDT electrodes 50, the reflectors 60, 61 and the lead electrodes 45A, 46A are formed of an Al film in terms of electrical characteristics, processing characteristics, and cost, but other conductive metal materials such as aluminum alloys may be used. Can also be used. The extraction electrodes 45 and 46, the auxiliary part 70, and the metal junction part 40 are formed in the Cr / Au film or the Cr / Ni / Au film with the same thickness.

The cover substrate 30 consists of a rectangular glass substrate, and tapered through holes 34 and 35 are formed from the surface 32 toward the rear surface 33. The through holes 34 and 35 are disposed in diagonal directions corresponding to the extraction electrodes 45 and 46 provided in the piezoelectric substrate 20 described above, respectively.

On the back surface 33 of the cover substrate 30, connection electrodes 73 and 74 having shapes corresponding to the extraction electrodes 45 and 46 are respectively formed at the entire circumference of the opening peripheral edges of the through holes 34 and 35 described above. It is formed over. Moreover, the metal junction part 41 is formed in the back surface 33 of the cover board | substrate 30 over the perimeter around the outer periphery.

The inner circumferential surfaces of each of the through holes 34 and 35 and the connecting electrodes 73 and 74 subsequent to the through holes 34 and 35 are covered with the through electrodes 75 and 76 made of a conductive metal material. In the surface 32 of the cover substrate 30, external electrodes 77 and 78 are formed at the peripheral edges of the through holes 34 and 35, respectively. The external electrodes 77 and 78 are electrically connected to the connection electrodes 73 and 74 through the through electrodes 75 and 76 provided in the through holes 34 and 35.

In the present embodiment, the cover substrate 30 is formed of soda glass having a coefficient of thermal expansion close to that of the crystal forming the piezoelectric substrate 20. In addition, the connection electrodes 73 and 74 and the metal junction part 41 are formed in the same thickness as Cr / Au film or Cr / Ni / Au film. The through electrodes 75 and 76 and the external electrodes 77 and 78 are similarly formed of a Cr / Au film or a Cr / Ni / Au film.

Besides the soda glass, the cover substrate 30 may be formed of another glass material or insulating material having the same or similar thermal expansion coefficient as the crystal, or the same crystal as the piezoelectric substrate 20. In addition, when the piezoelectric substrate 20 is formed of a piezoelectric material other than quartz, the cover substrate 30 may be formed of a thin sheet of insulating material having the same or similar thermal expansion coefficient as that of the piezoelectric material.

The surface acoustic wave chip 15 and the cover substrate 30 are integrated by thermally compressing the metal bonding portion 40, the metal bonding portion 41, the extraction electrodes 45, 46, and the connecting electrodes 73, 74, and the surface acoustic wave. The IDT electrode 50, the reflectors 60, 61, and the extraction electrodes 45, 46 are hermetically sealed in the space formed between the chip 15 and the cover substrate 30. In the present embodiment, the thicknesses of the extraction electrodes 45 and 46, the connection electrodes 73 and 74, and the metal bonding portion 40 and the metal bonding portion 41 are bonded to the IDT electrode 50 and the reflector 60, It is set to be thicker than the Al film of 61).

In addition, the auxiliary part 70 is made thicker than the Al film of the IDT electrode 50 and the reflectors 60 and 61, and is set thinner than the height of the space mentioned above.

As the joining means of the surface acoustic wave chip 15 and the cover substrate 30, an AuSn alloy film is formed on the upper surfaces of the extraction electrodes 45 and 46 and the metal bonding portion 40, and is thermally compressed or bonded by step bonding. The structure to join can also be employ | adopted.

Therefore, in the surface acoustic wave device 10 according to the first embodiment described above, since the auxiliary portion 70 is set lower than the height of the above-mentioned space and higher than the thickness of the IDT electrode 50, the piezoelectric substrate 20 or the cover Even if the substrate 30 is distorted due to a force from the outside, the cover substrate 30 is held by the auxiliary part 70, so that the cover substrate 30 is provided on the IDT electrode 50 and the reflectors 60 and 61. ) Does not come into contact with each other, so that the excitation and reception operation of the surface acoustic wave device expected in advance can be secured and maintained.

Moreover, this auxiliary | assistant part 70 is arrange | positioned inside a space, As shown in FIG. 2, the longitudinal direction is the range of the area | region of the IDT electrode 50 and the reflector 60, 61, and the width direction is the extraction electrode 45. As shown in FIG. Or since it is formed in the range in which the extraction electrode 46 is formed, even if the auxiliary | assistant part 70 is provided, a plane size does not become large.

Moreover, since the thickness of the auxiliary | assistant part 70 also exists in the range of the thickness which added the metal joining parts 40 and 41 (namely, the height of the space formed at the time of joining), the total thickness does not become thick either.

In addition, as in the above-described conventional technique, since there is no need to provide a recessed gap in the cover substrate 30, the structural strength of the cover substrate 30 can be formed high and thin. A surface acoustic wave device can be provided.

(Method for manufacturing surface acoustic wave device according to Embodiment 1)

Next, a method of manufacturing the surface acoustic wave device according to the present embodiment will be described with reference to the drawings.

4A to 4E are cross-sectional views showing an example of a manufacturing process of the surface acoustic wave device 10 according to the present embodiment. First, the large quartz wafer 21 in which the piezoelectric substrate 20 shown in FIG. 2 is arranged continuously in the vertical and horizontal directions is prepared. In FIG. 4A, a Cr / Au film having a predetermined thickness is formed on the surface 22 of the quartz wafer 21, and the extraction electrodes 45 and 46 and the metal junction portion 40 are formed using photolithography technology. The first layer 70A of the auxiliary portion 70 is formed in a desired shape.

Subsequently, an Al film having a predetermined thickness is formed on the surface 22 of the quartz wafer 21, and the IDT electrode 50, the reflectors 60, 61, and the lead electrodes 45A, 46A are formed using photolithography techniques. (See FIG. 2) in a desired shape, and the lead electrodes 45A and 46A are formed to be electrically connected to the extraction electrodes 45 and 46. As shown in FIG.

Here, when the formation process of the auxiliary part 70 is demonstrated in more detail, since the thickness of the 1st layer 70A of the auxiliary part 70 is the same as the metal junction part 40 and the extraction electrode 45 and 46, it is a metal junction part. After the process of forming the 40 and the extraction electrodes 45 and 46 and the first layer 70A of the auxiliary portion 70, the surface of the first layer 70A of the auxiliary portion 70 is again made to have an original thickness of the auxiliary portion. The auxiliary part 70 is formed by stacking Cr / Au films (the same material as the extraction electrodes 45 and 46) (see Fig. 4B).

Next, the manufacturing process of the cover substrate 30 is demonstrated. It demonstrates with reference to FIG. 4C.

First, the large glass substrate 31 which arrange | positioned the cover substrate 30 shown in FIG. 3 continuously in the vertical and horizontal direction is prepared. The through holes 34 and 35 of the cover substrate 30 are indirectly in the glass substrate 31 by sand blasting or etching. In particular, in the sand blasting process, the through holes 34 and 35 can be easily processed into a desired tapered shape.

Next, a Cr / Au film having a predetermined thickness is formed on the back surface 33 of the glass substrate 31 (the inner surface of the cover substrate when bonded), and the connection electrodes 73 and 74 and the photolithography technique are used. The metal junction part 41 is formed in a desired shape.

The cover substrate 30 (glass substrate 31 in this state) formed as mentioned above and the piezoelectric substrate 20 (crystal wafer 21) are bonded together.

A bonding process will be described with reference to FIG. 4D. The quartz wafer 21 and the glass substrate 31 are aligned up and down as shown in FIG. 4D, and the metal junction part 40, the metal junction part 41, the extraction electrodes 45 and 46, and the connection electrode ( 73, 74) in the contacted state. In this state, it joins together by the thermocompression bonding method which heats, pressurizing using a bonding apparatus.

In this state, the IDT electrode 50, the reflectors 60, 61 (see FIG. 1A) and the extraction electrodes 45, 56 are accommodated in the space formed between the surface acoustic wave chip 15 and the cover substrate 30. do.

Next, external electrodes 77 and 78 made of a Cr / Au film (or Cr / Ni / Au film) are formed on the surface 32 of the glass substrate 31 in a desired shape, and then the through electrode 75 is formed. , 76).

This will be described with reference to FIG. 4E. After the bonded laminate is washed, Cr films and Au films (or Cr films, Ni films and Au films) are formed on the inner circumferential surfaces of the through holes 34 and 35 and the connection electrodes 73 and 74 by sputtering or the like. By this, the through electrodes 75 and 76 are formed. Since the through holes 34 and 35 are formed in a tapered shape, they can be easily formed from the upper surface of the glass substrate 31 by sputtering or the like.

On the other hand, since the through electrodes 75 and 76 are thin films, the through holes 36 and 37 are formed in the center thereof.

Next, the conductive material is filled in the through holes 36 and 37 to form the sealing material 80. It demonstrates with reference to FIG. 1B. Since the inner surfaces of the through holes 36 and 37 are first formed with the through electrodes 75 and 76 of the metal film, and the wettability is improved, the sealing material 80 can facilitate the filling. Accordingly, conduction and through holes 36 are formed between the intersecting electrodes of the IDT electrode 50 and the corresponding external electrodes 77 and 78 via the connecting electrodes 73 and 74 and the extraction electrodes 45 and 46. And 37), the confidentiality is made more reliable and reliable.

Finally, the single surface acoustic wave device 10 shown in FIG. 1 is completed by dicing the stack of the glass substrate 31 and the quartz wafer 21 along the periphery 90 perpendicular to each other.

On the other hand, in the above-described manufacturing method, the auxiliary part 70 firstly forms the first layer 70A having the same thickness as the metal bonding part 40 and the extraction electrodes 45 and 46, and then again desires a metal film of the same material. Although lamination | stacking is carried out to the thickness, if the metal junction part 40 and the extraction electrode 45 and 46 are thicker than IDT electrode 50, and are thickness required in order to fulfill the function of the auxiliary | assistant part 70, further lamination process is unnecessary.

Therefore, according to the method for manufacturing the surface acoustic wave device of the first embodiment described above, the auxiliary portion 70 can be formed in the range of the extraction electrodes 45 and 46 forming process, and the auxiliary portion 70 can be formed in a wide range. It can be produced without the process increase.

In addition, since each of the extraction electrodes 45 and 46 is connected to the external electrodes 77 and 78 through the through electrodes 75 and 76 provided on the cover substrate 30, the extraction electrodes 45 and 46 do not cross the metal junction 40. As a result, airtightness in the space can be maintained.

In addition, by forming the first layer 70A of the auxiliary part 70 in the step of forming the extraction electrodes 45 and 46, and adding a lamination step of making a predetermined thickness, the thickness of the auxiliary part 70 is required. Correspondingly, one or more layers of metal films can be stacked again to freely form an auxiliary portion 70 of a desired thickness.

(Modification 1 of Embodiment 1)

Although the auxiliary part 70 arrange | positions the shape of several island shape in Embodiment 1 (refer FIG. 1, 2) mentioned above, the shape of the auxiliary part 70 is not limited to an island shape, Various shapes can be proposed. have.

5 is a plan view of the surface acoustic wave chip 15 according to Modification Example 1 of the first embodiment. The same code | symbol is attached | subjected to embodiment common to above-mentioned embodiment (refer FIG. 1-3). In addition, since a cross-sectional relationship is the same as that of Embodiment 1, illustration is abbreviate | omitted. The auxiliary part is composed of the auxiliary parts 71 and 72 formed over the lead electrode 45A or the lead electrode 46A along both sides of the IDT electrode 50 and the reflectors 60 and 61.

On the other hand, although the auxiliary parts 71 and 72 are provided over the range of the length direction of the IDT electrode 50 and the reflectors 60 and 61, the IDT electrode 50 and the reflector 60 and 61 and the metal junction part 40 are provided. From the dimensional relationship of the inner region of), even if only the range (both sides) of the IDT electrode 50 in the range to achieve the object of the present invention, it may be provided only on one side of the IDT electrode 50 and the reflectors 60, 61 good.

Even if it is formed in this way, it can exhibit the same effect as Embodiment 1 mentioned above.

(Modification 2 of Embodiment 1)

6 shows a surface acoustic wave chip 15 of another modification of the first embodiment. In the second modification, the extraction electrodes 45 and 46 are enlarged to form a function of the auxiliary part.

The extraction electrodes 45 and 46 are along both sides of the IDT electrode 50 and the longitudinal direction (the surface wave traveling direction) of the reflectors 60 and 61, and the longitudinal direction of the IDT electrode 50 and the reflector 60 and 61 is used. The range of the formation region and the width direction are formed in the range of the extraction electrodes 45 and 46 shown in Embodiment 1 (refer FIG. 1A).

The thickness of the extraction electrodes 45 and 46 of this modified example 2 is set to correspond to the height of the space mentioned above. That is, it is the same as the height which joined the metal junction part 40 and the metal junction part 41. FIG. At this time, in Embodiment 1, the connection electrodes 73 and 74 formed in the back surface 33 of the cover substrate 30 are unnecessary. In this way, the extraction electrodes 45 and 46 have a function as an auxiliary part.

As a joining method, although following the manufacturing method of Embodiment 1 mentioned above, it can carry out by the thermocompression method between the metal joint part 40 and the metal joint part 41. FIG.

When forming the extraction electrodes 45 and 46 like this modified example 2, another joining method can be employ | adopted. For example, it is a method of anodic bonding between the cover substrate 30 which consists of glass, the metal junction part 40, and the extraction electrodes 45 and 46. FIG. Here, since the cover substrate 30 and the metal joint part 40 are directly bonded, the metal joint part 41 provided in the cover substrate 30 shown in Embodiment 1 (refer FIG. 1B) mentioned above is not formed. In addition, the thickness of the metal junction part 40 and the extraction electrodes 45 and 46 shall be made the thickness of the space shown in Embodiment 1 mentioned above, ie, the metal junction parts 40 and 41 combined together. By doing in this way, joining of the cover substrate 30 and the surface acoustic wave chip 15 as an auxiliary | assistant part can be performed with the space of a required height.

In this way, by forming the take-out electrodes 45 and 46 of the shape shown in FIG. 6, the take-out electrode can have a function as an auxiliary part, and the above-mentioned effect can be exhibited without forming an auxiliary part again. Since this extraction electrode can be formed in the range of the magnitude | size of the plane provided in order to have a function as an original extraction electrode, the size of a surface acoustic wave device does not become large.

In FIG. 6, the through holes 34 and 35 are provided at the same diagonal positions as those of the first embodiment (see FIG. 1A), but their positions are, for example, the center positions of the extraction electrodes 45 and 46 (IDT electrodes). (50 longitudinal center position), and the like can be freely selected and installed, and the degree of freedom of connection layout with an external circuit (not shown) is also increased.

(Modification 3 of Embodiment 1)

Next, Modified Example 3 of Embodiment 1 will be described. In the third modified example, the auxiliary portion is formed using the same Al as the IDT electrode 50 when the IDT electrode 50 is formed, and the shape of the auxiliary portion is the first embodiment described above (see FIG. 2) and the modified example 1 thereof. Since it can be made similar to (refer FIG. 5), drawing is abbreviate | omitted.

In the modification 3 of the IDT electrode 50 (including the reflectors 60 and 61 and the lead electrodes 45A and 46A), after forming the first layer of the auxiliary portion, the first layer is continuously The Al layer is laminated on the surface so as to have a predetermined thickness of the auxiliary part.

Therefore, in the third modified example, the same effects as those of the first embodiment and the first modified example can be obtained.

(Embodiment 2)

Next, Embodiment 2 of this invention is described with reference to drawings. Embodiment 2 is characterized by forming the auxiliary portion on the surface of the bus bar constituting the IDT electrode and the reflector.

FIG. 7 shows a surface acoustic wave chip 15 according to the second embodiment, a is a plan view thereof, and b is a sectional view showing a B-B cutting plane of FIG. 7A. 7A and 7B, in the surface acoustic wave chip 15, the IDT electrode 50, the extraction electrodes 45 and 46, and the metal junction 40 are formed on the surface 22 of the piezoelectric substrate 20. It is formed by the manufacturing method of.

Here, the IDT electrode 50 (the reflectors 60, 61) is formed on the surface of the bus bars 51 and 52 (including the bus bars of the reflectors 60 and 61) that connect the crossover electrodes constituting the IDT electrode 50 to each other. After the formation, the auxiliary electrodes 53 and 54 as the auxiliary parts are stacked so that the total thickness becomes the same as the auxiliary part 70 (see FIG. 1B) described above. The auxiliary electrodes 53 and 54 are made of the same Al as the IDT electrode 50.

It is known that the arrangement of the auxiliary electrodes 53, 54 on the surfaces of the bus bars 51, 52 does not affect the excitation and reception characteristics. Therefore, when the auxiliary electrodes 53, 54 as auxiliary parts are disposed on the upper surfaces of the bus bars 51, 52, the auxiliary electrodes are disposed at the closest positions to the IDT electrode 50 and the reflectors 60, 61. Even if the height of (53, 54) is suppressed low, the objective of this invention can be achieved. The occupied regions of the auxiliary electrodes 53 and 54 also fall within the ranges of the IDT electrode 50 and the reflectors 60 and 61, contributing to the miniaturization of the surface acoustic wave device 10.

On the other hand, the auxiliary electrodes 53 and 54 are formed in the width | variety of the range which does not contact an intersection electrode with respect to the bus bars 51 and 52. As shown in FIG. This is to prevent the auxiliary electrodes 53 and 54 from being applied to the region of the crossover electrode even when there is a manufacturing nonuniformity in stacking the auxiliary electrodes 53 and 54. Even in this case, the object of the present invention can be achieved. It is not a distraction for you.

In addition, this invention is not limited to embodiment mentioned above, The deformation | transformation, improvement, etc. in the range which can achieve the objective of this invention are included in this invention.

That is, the present invention is mainly shown and described in particular with respect to specific embodiments, but the embodiments, embodiments, shapes, materials, combinations, and other details of the embodiments described above without departing from the spirit and scope of the present invention are described. Various modifications can be added by those skilled in the art in the processing method between the configuration and the manufacturing process.

Therefore, the descriptions limiting the shapes, materials, manufacturing processes, and the like disclosed above are provided for illustrative purposes in order to facilitate understanding of the present invention, and are not intended to limit the present invention. The description in the name of a member deviating from some or all of the limitations of the present invention is included in the present invention.

For example, in Embodiment 1 mentioned above, although the auxiliary | assistant part 70 is formed in the piezoelectric board | substrate 20 with the metal film of the same material as the extraction electrodes 45 and 46, the auxiliary | assistant part 70 is a material different from them, and the auxiliary part single body As a structure, the structure may be provided on the surface of the piezoelectric substrate 20.

In addition, an auxiliary part may be formed on the cover substrate 30. In this case, according to Embodiment 1, it continues to the formation process of the metal junction part 41 or the connection electrodes 73 and 74 in the area | region which does not contact the IDT electrode 50 and the reflectors 60 and 61, for example. Similar to the dimensional relationship between the auxiliary part 70 and the cover substrate 30, the dimensional relationship between the auxiliary part provided on the cover substrate 30 and the surface acoustic wave chip 15 can be formed in the same manner. Even with such a structure, it is possible to achieve the object of the present invention.

Therefore, according to the first to second embodiments described above, a surface acoustic wave device having a structure in which the IDT electrode and the cover substrate do not come into contact with each other even when the piezoelectric substrate and the cover substrate are distorted by an external force while realizing a compact and thin surface acoustic wave device. The manufacturing method can be realized by a simple process.

According to the present invention, it is possible to provide a surface acoustic wave device having a structure in which the IDT electrode and the cover substrate do not come into contact with each other even if the piezoelectric substrate and the cover substrate are distorted while realizing a compact and thin surface acoustic wave device, and a method of manufacturing the same.

Claims (10)

A surface acoustic wave chip having an IDT electrode formed on a main surface of a piezoelectric substrate, an extraction electrode drawn out from the IDT electrode, and a metal joint formed along an outer circumference of the main surface of the piezoelectric substrate; A cover substrate made of an insulating material and having a connection electrode connected to the extraction electrode provided on one main surface, an external electrode provided on the other main surface, and a through electrode connecting the connection electrode and the external electrode. and, The IDT electrode and the extraction electrode are hermetically sealed in a space formed by joining the surface acoustic wave chip and the cover substrate at the metal bonding portion, Inside the space, an auxiliary portion having a height such that the cover substrate does not contact the IDT electrode even if the piezoelectric substrate or the cover substrate is deformed is formed on the main surface of the piezoelectric substrate, And the auxiliary portion is a metal film formed along the longitudinal direction of the IDT electrode at a spaced position near the IDT electrode. delete The method according to claim 1, When the extraction electrode is provided in the range of the region where the IDT electrode is formed along the longitudinal direction of the IDT electrode, and the piezoelectric substrate and the cover substrate are bonded to each other, the extraction electrode is formed to have the same thickness as the height of the space and the auxiliary portion is formed. A surface acoustic wave device, which is also used both times. The method according to claim 1, The surface acoustic wave device, wherein the auxiliary portion is formed on a surface of a bus bar constituting the IDT electrode. Forming a surface acoustic wave chip having an IDT electrode provided on the main surface of the piezoelectric substrate, an extraction electrode drawn out from the IDT electrode, a metal joint formed along the outer periphery of the main surface of the piezoelectric substrate, and an auxiliary portion; Forming a cover substrate having a connection electrode connected to the extraction electrode provided on one main surface, an external electrode provided on the other main surface, and a through electrode connecting the connection electrode and the external electrode; Bonding the surface acoustic wave chip and the cover substrate at the metal bonding portion, and sealing the through electrode. The auxiliary part is formed at a height such that the cover substrate does not contact the IDT electrode even when the piezoelectric substrate or the cover substrate is deformed, and the auxiliary part is in a longitudinal direction of the IDT electrode at a position spaced near the IDT electrode. A surface acoustic wave device manufacturing method, characterized in that the metal film formed along the. The method according to claim 5, In the step of forming the auxiliary part, in the step of forming the extraction electrode or the metal junction part, the auxiliary part is formed after the first layer is formed of the same material as the extraction electrode at a position spaced apart from the IDT electrode and the extraction electrode. Method for producing a surface acoustic wave device comprising the step of laminating. The method according to claim 5, In the step of forming the extraction electrode, the extraction electrode is formed in the range of the region where the IDT electrode is formed along the longitudinal direction of the IDT electrode, and the extraction electrode is formed when the surface acoustic wave chip and the cover substrate are bonded to each other. A method of manufacturing a surface acoustic wave device, characterized by forming a thickness corresponding to an inner surface of a cover substrate. The method according to claim 5, The forming step of the auxiliary part includes the step of stacking the auxiliary part again after forming the first layer in the step of forming the IDT electrode in the same step as the IDT electrode in the vicinity of the IDT electrode. A method of manufacturing a surface acoustic wave device. The method according to claim 5, And the auxiliary portion is formed by an auxiliary portion forming step separate from the IDT electrode forming step and the extraction electrode forming step. The method according to claim 5, And the auxiliary portion is laminated on the surface of a bus bar constituting the IDT electrode with the same material as the IDT electrode after the step of forming the IDT electrode.

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