JP7048128B1 - Surface acoustic wave device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface acoustic wave device having thick wiring. SOLUTION: A plurality of resonators formed on a piezoelectric substrate, an external connection pad formed on the piezoelectric substrate, and electricity formed on the piezoelectric substrate and applied to at least one of the plurality of resonators. The first wiring connected to the wire, the support layer formed in the region other than the region where the plurality of resonators are formed on the piezoelectric substrate, and the plurality of resonators formed on the support layer. A cover layer to be tightly sealed, an external connection terminal electrically connected to the external connection pad, an insulating layer formed on the first wiring, and the first wiring formed on the insulating layer. A second wiring that intersects three-dimensionally is provided, and the support layer is not formed in the region where the second wiring is formed. [Selection diagram] Fig. 1

Description

The present disclosure relates to surface acoustic wave devices.

Surface acoustic wave devices are used, for example, as bandpass filters in front-end modules of mobile communication terminals such as smartphones. In recent years, modularization of wireless parts in mobile information terminals such as mobile phones and smartphones has progressed, and there is a demand for smaller and lower surface acoustic wave devices.

Therefore, the packaging technology of the surface acoustic wave device has also been improved, and a WLP (Wafer Level Package) structure using the chip itself of the surface acoustic wave device for packaging has been proposed.

Patent Document 1 discloses an elastic wave device having a WLP structure. In this elastic wave device, a support member is provided on a piezoelectric substrate so as to surround each resonator of a plurality of elastic wave resonators.

International Publication No. 2018/159111

In a surface acoustic wave device having a WLP structure, a thicker wiring is required. In particular, in a surface acoustic wave device formed as a small package, a thick film of wiring is required in order to improve heat dissipation and power resistance.

The present disclosure has been made to solve the above-mentioned problems. An object of the present disclosure is to provide a surface acoustic wave device with thick wiring.

The surface acoustic wave device according to the present disclosure is
Piezoelectric board and
A plurality of resonators formed on the piezoelectric substrate and
The external connection pad formed on the piezoelectric substrate and
A first wiring formed on the piezoelectric substrate and electrically connected to at least one of the plurality of resonators.
A support layer formed in a region other than the region where the plurality of resonators are formed on the piezoelectric substrate, and
A cover layer formed on the support layer and airtightly sealing the plurality of resonators,
An external connection terminal electrically connected to the external connection pad and formed in the through hole formed in the support layer and the cover layer and on the cover layer.
The insulating layer formed on the first wiring and
A second wiring formed on the insulating layer and three-dimensionally intersecting the first wiring is provided.
The support layer is not formed in the region where the second wiring is formed.

The insulating layer and the base wiring formed on the piezoelectric substrate are provided.
The present disclosure discloses that the lower surface of the second wiring is in contact with the base wiring through or without the intermediate layer of the conductive material, and the side surface of the second wiring is in contact with the side surface of the support layer. It is considered as one form.

The base wiring formed on the piezoelectric substrate is provided, and the base wiring is provided.
The lower surface of the second wiring is in contact with the base wiring and the insulating layer through or without the intermediate layer of the conductive material, and the side surface of the second wiring is in contact with the side surface of the support layer. , Is a form of the present disclosure.

The base wiring formed on the piezoelectric substrate is provided, and the base wiring is provided.
The lower surface of the second wiring is in contact with the base wiring with or without the intermediate layer of the conductive material and is in contact with the insulating layer, and the side surface of the second wiring is in contact with the side surface of the support layer. That is one form of the present disclosure.

It is one aspect of the present disclosure that at least two holes are formed in the cover layer in the region where the second wiring is formed.

It is one form of the present disclosure that the second wiring is solder.

The lower wiring formed on the piezoelectric substrate and
The upper wiring formed on the lower wiring and the upper wiring are provided.
Although the upper wiring is solder, it is a form of the present disclosure.

It is one aspect of the present disclosure that the internal wiring provided in the through hole of the support layer and the cover layer and exposed from the cover layer is provided.

It is one aspect of the present disclosure that the internal wiring has a ground potential.

One aspect of the present disclosure is that the second wiring is located at a position lower than the upper end of the support layer.

It is one aspect of the present disclosure that the thickness of the second wiring is 10 μm or more.

It is one embodiment of the present disclosure to include a support substrate made of sapphire, silicon, alumina, spinel, quartz or glass bonded to the piezoelectric substrate.

One form of the present disclosure is that the piezoelectric substrate is made of lithium tantalate, lithium niobate, quartz or piezoelectric ceramics.

According to the present disclosure, it is possible to provide a surface acoustic wave device having thick wiring.

It is sectional drawing of the elastic surface wave device which concerns on Embodiment 1. FIG. It is a top view of the surface acoustic wave device which concerns on Embodiment 1. FIG. It is sectional drawing of the elastic surface wave device which concerns on Embodiment 1. FIG. It is sectional drawing of the elastic surface wave device which concerns on Embodiment 2. FIG. It is sectional drawing of the elastic surface wave device which concerns on Embodiment 3. FIG. It is a flowchart which shows the manufacturing method of the surface acoustic wave device which concerns on Embodiment 4. It is sectional drawing of the surface acoustic wave device in the process of forming the 2nd wiring. It is sectional drawing of the surface acoustic wave device in the process of forming the 2nd wiring. It is sectional drawing of the surface acoustic wave device in the process of forming the 2nd wiring. It is a flowchart of the manufacturing method of the surface acoustic wave device which concerns on another example. It is a flowchart of the manufacturing method of the surface acoustic wave device which concerns on another example. It is a flowchart of the manufacturing method of the surface acoustic wave device which concerns on another example. It is sectional drawing of the elastic surface wave device which shows providing the material of the 2nd wiring before the formation of a cover layer.

The embodiments will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are designated by the same reference numerals. The duplicate description of the relevant part will be simplified or omitted as appropriate.

Embodiment 1.
FIG. 1 is a vertical sectional view of the surface acoustic wave device 10 according to the first embodiment. The surface acoustic wave device 10 includes a piezoelectric substrate 12. According to one example, the piezoelectric substrate 12 includes lithium tantalate (LiTaO3), lithium niobate (LiNbO3), crystal (SiO2), lithium borate (Li2B4O7), zinc oxide (ZnO), potassium niobate (KNbO3), and Langa. It consists of a site (La3Ga3SiO14) or piezoelectric ceramics.

A plurality of resonators are formed on the piezoelectric substrate 12. FIG. 1 shows that IDTs (Inter Digital Transducers) 15a and 15b were formed as a part of a plurality of resonators. According to one example, as a resonator, an IDT and a reflector that excite surface acoustic waves are formed. The IDT has a pair of opposed comb-shaped electrodes. The comb-shaped electrode has a bus bar connecting a plurality of electrode fingers and a plurality of electrode fingers. Reflectors can be provided on both sides of the IDT.

As an example of wiring, a first wiring 14a, a lower wiring 14b, and a base wiring 14c are formed on the piezoelectric substrate 12. For example, the first wiring 14a is electrically connected to at least one of the plurality of resonators.

An insulating layer 16 is formed on the first wiring 14a. According to one example, the insulating layer 16 is in contact with the upper surface and the side surface of the first wiring 14a. As a result, the insulating layer 16 is also in contact with the piezoelectric substrate 12.

The support layer 22 is formed in a region other than the region on which the plurality of resonators are formed on the piezoelectric substrate 12. There is a cover layer 24 on the support layer 22. The resonator including the IDT 15a is hermetically sealed by the piezoelectric substrate 12, the support layer 22, and the cover layer 24. This provides the cavity 26a. The resonator including the IDT 15b is hermetically sealed by the piezoelectric substrate 12, the support layer 22, and the cover layer 24. This provides the cavity 26b. In this way, the cover layer 24 airtightly seals the plurality of resonators.

Base wiring 14c is formed on and on the side surface of the insulating layer 16 so as to cover the insulating layer 16. The base wiring 14c is wiring formed on the insulating layer 16 and the piezoelectric substrate 12. A second wiring 20a is provided on the base wiring 14c via an intermediate layer 18a of a conductive material. In this example, the base wiring 14c, the intermediate layer 18a and the second wiring 20a provide one thick wiring. According to another example, the intermediate layer 18a can be omitted.

The lower surface of the second wiring 20a is in contact with the base wiring 14c via the intermediate layer 18a or not via the intermediate layer 18a. The side surface of the second wiring 20a is in contact with the side surface of the support layer 22. In other words, the shape of the second wiring 20a in a plan view is defined by the support layer 22.

The support layer 22 is not formed in the region where the second wiring 20a is formed. In the example of FIG. 1, the region where the second wiring 20a is formed is indicated by x1. The support layer 22 is not formed in this range of x1.

The first wiring 14a is a wiring extending in the positive and negative directions. On the other hand, the base wiring 14c, the intermediate layer 18a, and the second wiring 20a are wirings extending in the x positive and negative directions. In other words, the longitudinal direction of the first wiring 14a is parallel to the y-axis. The longitudinal direction of the base wiring 14c, the intermediate layer 18a, and the second wiring 20a is parallel to the x-axis. Therefore, the second wiring 20a is a wiring formed on the insulating layer 16 and three-dimensionally intersecting with the first wiring 14a.

At least two holes are formed in the cover layer 24 in the region where the second wiring 20a is formed. In the example of FIG. 1, holes 24a and 24b are formed in the cover layer 24.

An upper wiring 20b is provided on the lower wiring 14b via an intermediate layer 18b of the conductor material. In this example, the lower wiring 14b, the intermediate layer 18b and the upper wiring 20b provide one thick wiring. According to another example, the intermediate layer 18b can be omitted.

The lower surface of the upper wiring 20b is in contact with the lower wiring 14b via the intermediate layer 18b or not via the intermediate layer 18b. The side surface of the upper wiring 20b is in contact with the side surface of the support layer 22. The shape of the upper wiring 20b in a plan view is defined by the support layer 22. The intermediate layers 18a and 18b may be provided as, for example, a UBM (Under Bump Metal) or a seed layer.

The material of the second wiring 20a and the upper wiring 20b is, for example, solder. The second wiring 20a and the upper wiring 20b are formed for thickening the wiring. The thickness of the second wiring 20a and the upper wiring 20b is, for example, 10 μm or more. By providing thick wiring, the resistance of the wiring can be lowered, the heat dissipation property can be improved, and the power resistance performance can be improved. According to one example, the line and space (L / S) of the second wiring 20a and the upper wiring 20b formed of such solder is, for example, 10/10 μm.

According to one example, the second wiring 20a and the upper wiring 20b are located lower than the upper end of the support layer 22. As a result, there is a gap 26c between the cover layer 24 and the second wiring 20a, and there is a gap 26d between the cover layer 24 and the upper electrode 20b.

FIG. 2 is a plan view of the surface acoustic wave device 10. FIG. 1 corresponds to a cross-sectional view taken along the line I-I'of FIG. FIG. 2 shows that the external connection terminal 30 and the internal wiring 39 are exposed on the upper surface of the surface acoustic wave device 10. According to one example, the external connection terminal 30 is used for transmitting and receiving an electric signal, and the internal wiring 39 is used for providing a ground potential. When mounting the surface acoustic wave device 10 having a WLP structure on a substrate, a plurality of external connection terminals 30 and internal wiring 39 are joined to the substrate.

In FIG. 2, the planar shapes of the cavities 26a and 26b, the second wiring 20a, and the upper wiring 20b are shown by broken lines. The second wiring 20a is a wiring extending in the x positive / negative direction, and the upper wiring 20b is a wiring extending in the y positive / negative direction. Immediately above the second wiring 20a, there are holes 24a and 24b of the cover layer 24. Immediately above the upper wiring 20b, there is a hole 24c of the cover layer 24. The holes in the cover layer 24 are sufficiently smaller than the wiring area.

FIG. 3 is a cross-sectional view taken along the line III-III'of the surface acoustic wave device of FIG. An external connection pad 31 is formed on the piezoelectric substrate 12. According to one example, the upper portion of the support layer 22 and the cover layer 24 on the external connection pad 31 is a through hole 32. The external connection terminal 30 is formed in the through hole 32 and is electrically connected to the external connection pad 31. The external connection terminal 30 projects upward from the upper surface of the cover layer 24.

According to one example, the internal wiring 39 also has the same shape as the external connection terminal 30. Specifically, an internal wiring pad is provided in contact with the piezoelectric substrate 12. There are through holes for the support layer 22 and the cover layer 24 on the internal wiring pad, and the internal wiring 39 is formed in the through holes. As a result, the internal wiring 39 and the internal wiring pad are electrically connected. The internal wiring 39 may project above the cover layer 24.

In the surface acoustic wave device described with reference to FIG. 1-3, the IDT 15a, 15b, the first wiring 14a, the base wiring 14c, the lower wiring 14b, the external connection pad 31, and the internal wiring pad are made of a film of a conductive material. be. As the conductive material, for example, an aluminum (Al) alloy typified by an aluminum-copper (Al-Cu) alloy, an aluminum (Al) single metal, or a film in which a plurality of layers made of different types of conductive materials are laminated is adopted. obtain.

The wiring line and space (L / S) is, for example, 10/10 μm. For example, the wiring provided with the base wiring 14c and the second wiring 20a can have a width of 10 μm and a height of 20 μm. Further, the wiring provided with the lower wiring 14b and the upper wiring 20b can have a width of 10 μm and a height of 20 μm. Making the support layer 22 and the cover layer 24 thinner contributes to lowering the height of the device. By further reducing the L / S according to the reduction in height of the device, the device can be miniaturized.

According to one example, the support substrate can be joined to the lower surface of the piezoelectric substrate 12. The support substrate consists of, for example, sapphire, silicon, alumina, spinel, quartz or glass.

The surface acoustic wave device 10 may be any of a filter, a resonator, a delay line, a trap, and the like. Further, the elastic wave excited by the IDTs 15a and 15b may be any of Rayleigh wave, SH wave and the like. Further, when the surface acoustic wave device 10 is a filter, the surface acoustic wave device 10 may be either a resonator type filter or a transversal type filter.

Embodiment 2.
Since the surface acoustic wave device according to the second embodiment has many similarities to the first embodiment, the description of the similar parts will be omitted, and the differences from the first embodiment will be mainly described.

FIG. 4 is a cross-sectional view of the surface acoustic wave device according to the second embodiment. The base wirings 14d and 14e are formed on the piezoelectric substrate 12. A second wiring 20c is formed on the base wirings 14d and 14e and the insulating layer 16 with or without the intermediate layer 18c. According to one example, the material of the second wiring 20c is solder. The wiring having the second wiring 20c and the base layers 14d and 14e is a wiring that three-dimensionally intersects with the first wiring 14a. The second wiring 20c is provided as a bridge wiring.

The lower surface of the second wiring 20c is in contact with the base wirings 14d and 14e and the insulating layer 16 via the intermediate layer 18c of the conductive material or not via the intermediate layer 18c. The side surface of the second wiring 20c is in contact with the side surface of the support layer 22. Therefore, the shape of the second wiring 20c is defined by the support layer 22 in a plan view.

Since the base wiring 14c of the first embodiment must be formed after the formation of the first wiring 14a and the insulating layer 16, the step for forming the wiring is required at least twice. On the other hand, in the second embodiment, since the base wiring is not formed on the insulating layer 16, the first wiring 14a and the base wirings 14d and 14e can be formed at the same time in one step. Therefore, the manufacturing process is simplified.

Embodiment 3.
Since the surface acoustic wave device according to the third embodiment has many similarities to the second embodiment, the description of the similar parts will be omitted, and the differences from the second embodiment will be mainly described.

FIG. 5 is a cross-sectional view of the surface acoustic wave device according to the third embodiment. The second wiring 20d is provided as a bridge wiring. There is an intermediate layer 18d on the base wirings 14d and 14e, but there is no intermediate layer on the insulating layer 16. Therefore, the lower surface of the second wiring 20d is in contact with the base wirings 14d and 14e via the intermediate layer 18d of the conductive material, and is in contact with the insulating layer 16. The side surface of the second wiring 20d is in contact with the side surface of the support layer 22.

When the second wiring 20d is solder, the intermediate layer 18d is provided to improve the wettability of the second wiring 20d. According to the third embodiment, since the intermediate layer 18d is provided, the base wirings 14d and 14e can be reliably joined to the second wiring 20d. On the other hand, by omitting the intermediate layer between the insulating layer 16 and the second wiring 20d, it is possible to provide a device suitable for cost reduction. If the base wirings 14d and 14e can be joined to the second wiring, the intermediate layer between them can be omitted.

Embodiment 4.
FIG. 6 is a flowchart of a method for manufacturing a surface acoustic wave device according to the fourth embodiment. First, in step S1, a plurality of resonators, an external connection pad 31, and a first wiring 14a electrically connected to at least one of the plurality of resonators are formed on the piezoelectric substrate 12. In step S1, other configurations may be formed. For example, in step S1, in addition to the above-mentioned portions, the lower wiring 14b and the internal wiring pad can be formed. According to one example, the plurality of resonators, the external connection pad 31, the first wiring 14a, the lower wiring 14b, and the internal wiring pad are formed in the same process.

When manufacturing the surface acoustic wave device shown in FIG. 4, the base wirings 14d and 14e are formed in addition to the above-mentioned portions in step S1. When manufacturing the surface acoustic wave device shown in FIG. 5, in step S1, the base wirings 14d and 14e shown in FIG. 5 are formed in addition to the above-mentioned portions. For example, at the same time as forming a plurality of resonators, an external connection pad 31, an internal wiring pad, a lower wiring 14b, and a first wiring 14a, base wirings 14d and 14e are formed on the left and right sides of the first wiring 14a.

According to one example, the conductor layer formed in this step is a film formed by a thin film forming method such as a sputtering method, a vapor deposition method, or a CVD (Chemical Vapor Deposition) method, and is formed by a reduced projection exposure machine (stepper) and RIE (stepper). It can be obtained by patterning by a photolithography method or the like using a Reactive Ion Etching) device and processing it into a desired shape.

Then, the process proceeds to step S2. In step S2, the insulating layer 16 and the intermediate layers 18a and 18b are formed. When manufacturing the surface acoustic wave device of FIG. 1, the base wiring 14c is also formed. That is, in the case of manufacturing the surface acoustic wave device of FIG. 1, the insulating layer 16 is first formed, and then the base wiring 14c is formed on the insulating layer 16 by a photolithography method or the like. Thereby, after the step of forming the insulating layer 16 and before the step of forming the second wiring 20a, the base wiring 14c that three-dimensionally intersects with the first wiring 14a is formed on the insulating layer 16. Further, an intermediate layer 18a, which is a base metal layer, is formed on the base wiring 14c. After this or at the same time, an intermediate layer 18b, which is a base metal layer, is formed on the lower wiring 14b.

When manufacturing the surface acoustic wave device of FIG. 4, the insulating layer 16 and the intermediate layers 18b and 18c are formed in step S2. When manufacturing the surface acoustic wave device of FIG. 5, the insulating layer 16 and the intermediate layers 18b and 18d are formed in step S2. According to one example, as shown in FIGS. 4 and 5, the insulating layer 16 can be formed so as to cover the first wiring 14a. In the case of manufacturing the surface acoustic wave device of FIG. 4, after forming the insulating layer 16, an intermediate layer 18c, which is a base metal layer, is formed on the base wirings 14d and 14e and the insulating layer 16, and above the lower wiring 14b. An intermediate layer 18b, which is a base metal layer, is formed on the surface. When manufacturing the surface acoustic wave device of FIG. 5, after forming the insulating layer 16, an intermediate layer 18d, which is a base metal layer, is formed on the base wirings 14d and 14e, and a base metal layer is formed on the lower wiring 14b. The intermediate layer 18b is formed. The intermediate layers 18a, 18b, 18c, and 18d of FIGS. 1, 4, and 5 are provided to improve the wettability of the solder, according to one example.

Then, the process proceeds to step S3. In step S3, the support layer 22 and the cover layer 24 are formed. First, a support layer 22 higher than the insulating layer 16 is formed on the piezoelectric substrate 12. The support layer 22 may be formed by patterning a film formed on the piezoelectric substrate 12 by a normal film forming method, or may be formed by bonding a separately prepared film on the piezoelectric substrate 12. May be good.

When the support layer 22 is formed by the former method, for example, the support layer 22 can be formed by patterning the resist film by a photolithography method and then curing the resist film. In this case, as the resist, for example, a photosensitive resin such as an epoxy resin, a polyimide resin, a BCB (benzocyclobutene) resin, or an acrylic resin can be used. The method for forming a film made of a resist is represented by a method using a photosensitive dry film and a method using a photosensitive liquid resist. When a photosensitive dry film is used, the photosensitive dry film can be attached to the surface of a surface acoustic wave device wafer or substrate with good adhesion by using a vacuum laminator or the like. When a photosensitive dry film is used, it is possible to form a relatively thick support layer 22 having excellent adhesion, which is more than 10 μm. When a photosensitive liquid resist is used, it can be formed by applying a resist liquid by, for example, a spin coating method, a printing method, or the like. Above all, it is desirable to form a film made of a resist by the spin coating method. When a film made of resist is formed by the spin coating method, even if there is a slight step in the underlying structure, the resist film can be formed without creating a gap between the underlying structure and the underlying structure, and the adhesion is good. This is because it is possible to form an excellent support layer 22.

The resist film thus formed is processed into a support layer 22 formed in a region other than the region in which the IDT is formed through an exposure step and a developing step. The thickness of the support layer 22 can be, for example, 20 μm. According to another example, another thickness is adopted.

Next, a film-shaped cover layer 24 is placed on the upper surface of the support layer 22 to join the support layer 22 and the cover layer 24. The cover layer 24 can provide cavities 26a and 26b, which are vibration spaces sealed in the region where the IDTs 15a and 15b are formed, respectively. The cover layer 24 airtightly seals a plurality of resonators.

According to one example, in order to place the cover layer 24 on the upper surface of the support layer 22, the temperature and pressure are adjusted by using a pasting machine capable of pressurizing and pasting the film with a roller while controlling the temperature. The cover layer 24 is attached to the upper surface of the support layer 22 with appropriate settings.

In order to join the support layer 22 and the cover layer 24, the support layer 22 and the cover layer 24 may be heated or the support layer 22 and the cover layer 24 may be irradiated with light, depending on the material. For example, when an epoxy resin is used as the material of the support layer 22 and the cover layer 24, the support layer 22 and the cover layer 24 may be heated to about 100 ° C. With the cover layer 24 formed in this way, a vibration space (cavity area) can be provided, and IDTs 15a and 15b can be sealed, so that oxidation of IDTs and the like can be reduced. The thickness of the cover layer 24 can be, for example, 20 μm to 45 μm.

If the support layer 22 and the cover layer 24 are made of the same material, both can be integrated when the support layer 22 and the cover layer 24 are joined. Since the bonding interface between the two is the interface between the same materials, it is possible to improve the adhesion strength between the two and the airtightness of the cover layer 24. In particular, when an epoxy resin is used as the material for both and heated in the range of 100 ° C to 200 ° C, the polymerization is further promoted, so that the adhesion strength between the two and the airtightness of the cover layer 24 are improved. be able to.

According to one example, a plurality of holes are formed in the cover layer 24. The holes in the cover layer 24 are formed, for example, directly above the area where the base wiring is located and directly above the area where the lower wiring 14b is located. In other words, a hole in the cover layer 24 is formed directly above the region where the thickening of the wiring is planned. In the example of FIG. 2, it is illustrated that the holes 24a, 24b, and 24c are formed in the cover layer 24. The holes in the cover layer 24 may be formed before the cover layer 24 is joined to the support layer 22, or may be formed after the cover layer 24 is joined to the support layer 22.

Then, the process proceeds to step S4. In step S4, the second wiring 20a whose side surface is in contact with the support layer 22 is formed in the region above the insulating layer 16. At the same time, the upper wiring 20b is formed.

7-9 is a diagram showing an example of a process of forming the second wiring 20a and the upper wiring 20b. First, as shown in FIG. 7, a metal mask 40, a squeegee 50, a metal paste pressurizing supply head 52, and a metal paste 54 are prepared. The metal mask 40 is formed with mask openings 40a and 40b. A mask opening is also formed directly above the lower wiring 14b. These mask openings are provided directly above the holes in the cover layer 24. According to one example, the mask opening and the hole of the cover layer 24 have a one-to-one correspondence. That is, there is one hole in the cover layer 24 directly below one mask opening. According to one example, the width of the mask opening is larger than the width of the holes in the cover layer 24.

FIG. 8 illustrates that by advancing the squeegee 52, the metal pastes 54a, 54b were provided on the intermediate layer 18a via the mask openings 40a, 40b and the holes 24a, 24b of the cover layer 24. ing. Further, as the squeegee 52 progresses, the metal paste 54c is provided on the intermediate layer 18b via the mask opening and the hole 24c of the cover layer 24.

As described above, in the step of forming the second wiring, first, a paste-like metal (hereinafter, may be simply referred to as metal) is pushed into the holes of the cover layer 24 to provide the metal to the region above the insulating layer 16. .. According to one example, the metal is provided in the region above the insulating layer 16 through at least two holes in the cover layer 24. If there is no intermediate layer 18a, the metal is in contact with the base wiring 14c, and if there is an intermediate layer 18a, the metal is in contact with the intermediate layer 18a.

After that, as shown in FIG. 9, when the metal mask 40 is retracted, a metal to be a second electrode remains on the intermediate layers 18a and 18b, in the hole of the cover layer 24, and above the cover layer 24. According to another example, due to the relationship between the opening area of the metal mask and the thickness of the metal mask, the mold release becomes poor, and the metal in the metal mask remains in the metal mask.

Then, the process proceeds to step S5. In step S5, the external connection terminal 30 is formed. In step S5, first, a through hole penetrating the support layer 22 and the cover layer 24 is formed in the region where the external connection pad 31 is formed. For example, the through hole 32 shown in FIG. 3 is formed. After that, the external connection terminal 30 is formed in the through hole 32.

According to one example, the step of forming the external connection terminal 30 is performed by using a first mask having a plurality of holes. Specifically, by advancing the squeegee, a metal material is provided in the through hole 32 through the mask opening of the first mask. According to one example, a second mask having a plurality of holes smaller than the plurality of holes in the first mask is provided as a metal mask used for forming the second wiring.

According to another example, the external connection terminal 30 is formed in the same step as the step of forming the second wiring 20a. That is, the above-mentioned metal mask 40 is provided with a mask opening located directly above the external connection pad 31. Then, the metal paste is provided to the region above the insulating layer 16 through the mask opening and the hole of the cover layer 24, and the metal which is the material of the external connection terminal 30 is provided through another mask opening and the hole of the cover layer 24. The paste is provided on the external connection pad 31. Also in the case of manufacturing the surface acoustic wave device of FIG. 4 or 5, the metal paste can be provided by the same method as described above.

Then, the process proceeds to step S6. In step S6, the paste-like metal becomes the shape of the above-mentioned second wiring and the upper wiring 20b by the reflow process. According to one example, the metal provided in the region above the insulating layer 16 and the metal provided above the intermediate layer 18b are solders. By subjecting this solder to a solder reflow step and a flux cleaning step, the second wiring and the lower wiring shown in FIGS. 1, 4 and 5 are provided. In this way, the second wiring that three-dimensionally intersects with the first wiring 14a is provided.

In the manufacturing method described with reference to FIG. 6, the metal paste is provided in step S4, the metal paste is also provided in step S5, and the reflow process is performed in step S6, so that two printings and one reflow are performed. It can be said to include.

FIG. 10 is a flowchart of a method for manufacturing a surface acoustic wave device according to another example. Steps S1-S4 are the same processes as steps S1-S4 described with reference to FIG. In the example of FIG. 10, a reflow step and a flux cleaning step for forming the second wiring and the upper wiring are carried out in step S5. Next, in step S6, a paste-like metal is provided on the external connection pad 31. Next, in step S7, a reflow step and a flux cleaning step are performed on the paste-like metal on the external connection pad 31. As a result, the external connection terminal 30 is formed.

As described above, in the example of FIG. 10, a reflow step and a flux cleaning step for forming the second wiring and the upper wiring are performed, and a reflow step and a flux cleaning step for forming the external connection terminal 30 are separately performed. Is done. Therefore, the reflow process and the flux cleaning process can be optimized according to the manufacturing target.

In the manufacturing method described with reference to FIG. 10, the metal paste is provided in step S4, the reflow process is performed in step S5, the metal paste is provided in step S6, and the reflow process is performed in step S7. It can be said to include two prints and two reflows.

FIG. 11 is a flowchart of a method for manufacturing a surface acoustic wave device according to another example. Steps S1-S3 are the same processes as steps S1-S3 described with reference to FIG. In the example of FIG. 11, in step S4, the metal paste for forming the second wiring and the upper wiring and the metal paste for forming the external connection terminal are simultaneously provided on the intermediate layer.

Next, in step S5, a reflow step and a flux cleaning step for forming the second wiring, the upper wiring 20b, and the external connection terminal 30 are performed. In the manufacturing method described with reference to FIG. 11, all the necessary metal pastes are collectively provided in step S4, and the second wiring, the upper wiring 20b, and the external connection are performed by the reflow process and the flux cleaning process in step S5. The terminal 30 is formed.

Since the manufacturing method described with reference to FIG. 11 provides the metal paste in step S4 and performs the reflow process in step S5, it can be said that one printing and one reflow are included.

FIG. 12 is a flowchart of a method for manufacturing a surface acoustic wave device according to another example. Steps S1 and S2 are the same processes as steps S1 and S2 described with reference to FIG. In the example of FIG. 12, the support layer 22 is formed in step S3. Then, in step S4, the metal paste is provided without the cover layer.

FIG. 13 is a diagram showing that the metal paste is provided without the cover layer. The metal paste extruded by the squeegee 50 is provided on the intermediate layers 18a, 18b via the mask opening. At the same time, or in a separate step from this, a metal paste as a material for the external connection terminal 30 is provided on the external connection pad 31.

Then, in step S5 of FIG. 12, all the metal pastes are subjected to reflow treatment and flux cleaning treatment. As described above, when the metal pace is solder, this reflow process can be said to be a solder reflow process.

Next, in step S6 of FIG. 12, the cover layer 24 is formed on the support layer 22. Since the second wiring and the upper wiring are formed before the cover layer 24 is formed, the cover layer 24 does not need a hole for forming the second wiring and the upper wiring. Therefore, for example, there is no hole in the cover layer 24 directly above the region where the first wiring, the insulating layer 16, the base wiring, and the lower wiring 14b are formed. For example, in the example of FIG. 2, the holes 24a, 24b, and 24c can be omitted. The cover layer 24 manufactured in the flowchart of FIG. 12 is formed with a through hole for exposing the external connection terminal 30 and the internal wiring 39.

In the example described with reference to FIGS. 12 and 13, the second wiring was formed by providing metal to the region above the insulating layer through the mask opening prior to the formation of the cover layer 24. This increases the degree of freedom in the opening area of the cover layer.

Although some aspects of at least one embodiment have been described, it should be appreciated that various modifications, modifications and improvements are readily recalled to those of skill in the art. Such modifications, modifications and improvements are intended to be part of and within the scope of this disclosure.

It should be understood that the methods and embodiments of the apparatus described herein are not limited to application to the details of the structure and arrangement of the components described above or illustrated in the accompanying drawings. Methods and devices can be implemented in other embodiments and implemented or implemented in various embodiments.

Specific implementation examples are given herein for illustrative purposes only and are not intended to be limited.

The expressions and terms used in this disclosure are for explanatory purposes only and should not be considered limiting. The use of "include", "provide", "have", "include" and variations thereof herein means inclusion of the items listed below and their equivalents and additional items.

References to "or (or)" shall be construed so that any term described using "or (or)" refers to one, more than, and all of the terms in the description. Can be done.

References to front / back / left / right, top / bottom, horizontal / vertical, and front / back are all intended for the convenience of description. The reference is not limited to any one of the positional or spatial orientations of the components of the present disclosure. Therefore, the above description and drawings are merely examples.

10 Surface Acoustic Wave Device, 12 Surface Acoustic Wave Device, 14a 1st Wiring, 14b Bottom Wiring, 14c, 14d, 14e Base Wiring, 16 Insulation Layer, 18a, 18b, 18c, 18d Intermediate Layer, 20a 2nd Wiring, 20b Top Wiring, 22 Support layer, 24 Cover layer, 30 External connection terminal, 39 Internal wiring, 50 Squeegee, 52 Metal paste pressure supply head, 54 Metal paste

Claims (13)

Piezoelectric board and
A plurality of resonators formed on the piezoelectric substrate and
The external connection pad formed on the piezoelectric substrate and
A first wiring formed on the piezoelectric substrate and electrically connected to at least one of the plurality of resonators.
A support layer formed in a region other than the region where the plurality of resonators are formed on the piezoelectric substrate, and
A cover layer formed on the support layer and airtightly sealing the plurality of resonators,
An external connection terminal electrically connected to the external connection pad and formed in the through hole formed in the support layer and the cover layer and on the cover layer.
The insulating layer formed on the first wiring and
A second wiring formed on the insulating layer and three-dimensionally intersecting the first wiring,
The insulating layer and the base wiring formed on the piezoelectric substrate are provided.
The support layer is not formed in the region where the second wiring is formed, and the support layer is not formed.
A surface acoustic wave device in which the lower surface of the second wiring is in contact with the base wiring with or without an intermediate layer of a conductive material, and the side surface of the second wiring is in contact with the side surface of the support layer . Piezoelectric board and
A plurality of resonators formed on the piezoelectric substrate and
The external connection pad formed on the piezoelectric substrate and
A first wiring formed on the piezoelectric substrate and electrically connected to at least one of the plurality of resonators.
A support layer formed in a region other than the region where the plurality of resonators are formed on the piezoelectric substrate, and
A cover layer formed on the support layer and airtightly sealing the plurality of resonators,
An external connection terminal electrically connected to the external connection pad and formed in the through hole formed in the support layer and the cover layer and on the cover layer.
The insulating layer formed on the first wiring and
A second wiring formed on the insulating layer and three-dimensionally intersecting the first wiring,
With a base wiring formed on the piezoelectric substrate,
The support layer is not formed in the region where the second wiring is formed, and the support layer is not formed.
The lower surface of the second wiring is in contact with the base wiring and the insulating layer through or without the intermediate layer of the conductive material, and the side surface of the second wiring is a surface acoustic wave in contact with the side surface of the support layer. device. Piezoelectric board and
A plurality of resonators formed on the piezoelectric substrate and
The external connection pad formed on the piezoelectric substrate and
A first wiring formed on the piezoelectric substrate and electrically connected to at least one of the plurality of resonators.
A support layer formed in a region other than the region where the plurality of resonators are formed on the piezoelectric substrate, and
A cover layer formed on the support layer and airtightly sealing the plurality of resonators,
An external connection terminal electrically connected to the external connection pad and formed in the through hole formed in the support layer and the cover layer and on the cover layer.
The insulating layer formed on the first wiring and
A second wiring formed on the insulating layer and three-dimensionally intersecting the first wiring,
With a base wiring formed on the piezoelectric substrate,
The support layer is not formed in the region where the second wiring is formed, and the support layer is not formed.
The lower surface of the second wiring is in contact with the base wiring with or without the intermediate layer of the conductive material, and is in contact with the insulating layer, and the side surface of the second wiring is in contact with the side surface of the support layer. Surface acoustic wave device. Piezoelectric board and
A plurality of resonators formed on the piezoelectric substrate and
The external connection pad formed on the piezoelectric substrate and
A first wiring formed on the piezoelectric substrate and electrically connected to at least one of the plurality of resonators.
A support layer formed in a region other than the region where the plurality of resonators are formed on the piezoelectric substrate, and
A cover layer formed on the support layer and airtightly sealing the plurality of resonators,
An external connection terminal electrically connected to the external connection pad and formed in the through hole formed in the support layer and the cover layer and on the cover layer.
The insulating layer formed on the first wiring and
A second wiring formed on the insulating layer and three-dimensionally intersecting the first wiring is provided.
The support layer is not formed in the region where the second wiring is formed, and the support layer is not formed.
A surface acoustic wave device in which at least two holes are formed in the cover layer in the region where the second wiring is formed . The surface acoustic wave device according to any one of claims 1 to 3, wherein at least two holes are formed in the cover layer in the region where the second wiring is formed. The surface acoustic wave device according to any one of claims 1 to 5, wherein the second wiring is solder. The lower wiring formed on the piezoelectric substrate and
The upper wiring formed on the lower wiring and the upper wiring are provided.
The surface acoustic wave device according to any one of claims 1 to 6, wherein the upper wiring is solder. The elastic surface wave device according to any one of claims 1 to 7, which is provided in the through hole of the support layer and the cover layer and includes internal wiring exposed from the cover layer. The surface acoustic wave device according to claim 8, wherein the internal wiring is a ground potential. The surface acoustic wave device according to any one of claims 1 to 9, wherein the second wiring is located at a position lower than the upper end of the support layer. The surface acoustic wave device according to any one of claims 1 to 10, wherein the thickness of the second wiring is 10 μm or more. The surface acoustic wave device according to any one of claims 1 to 11, further comprising a support substrate made of sapphire, silicon, alumina, spinel, crystal or glass bonded to the piezoelectric substrate. The surface acoustic wave device according to any one of claims 1 to 12, wherein the piezoelectric substrate is made of lithium tantalate, lithium niobate, quartz or piezoelectric ceramics.

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