Method for manufacturing a surface acoustic wave device

Abstract

A method for manufacturing a surface acoustic wave (SAW) device includes: forming a plurality of resonators, external connection pads, and a first wiring electrically connecting at least one of the resonators on a piezoelectric substrate; providing an insulating layer covering the first wiring; forming a support layer on the piezoelectric substrate that is higher than the insulating layer; forming a second wiring in a region above the insulating layer to laterally connect to the support layer; and forming a hermetically sealing cover layer on the support layer before or after the formation of the second wiring. This provides a method for manufacturing a SAW device with thick wiring.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an elastic surface wave device. Background Technology

[0002] Surface elastic wave (SEL) devices are used, for example, as bandpass filters in the front-end modules of mobile communication terminals such as smartphones. In recent years, with the continuous development of modular wireless components in portable information terminals such as mobile phones and smartphones, miniaturization and low-profile design of SEL devices have become essential.

[0003] Therefore, a technique for improving the packaging structure of a surface wave device is proposed, which uses the chip of the surface wave device for packaging in a WLP (Wafer Level Package) structure.

[0004] Patent document 1 (International Publication No. 2018 / 159111) discloses an elastic wave device with a WLP structure. The elastic wave device has a support assembly on a piezoelectric substrate that surrounds each resonator of several elastic wave resonators. Summary of the Invention

[0005] In WLP (Wireless Surface Wave) devices, thickening the wiring is necessary. In particular, for WLP devices with small package structures, thickened wiring is essential to improve heat dissipation and electrical withstand capability.

[0006] In order to solve the above problems, the present disclosure aims to provide a method for manufacturing an elastic surface wave device with thick wiring.

[0007] This disclosure describes a method for manufacturing an elastic surface wave device, comprising:

[0008] The steps for forming the first wiring are: forming a plurality of resonators, external connection pads, and a first wiring that electrically connects at least one of the resonators on a piezoelectric substrate;

[0009] The step of forming an insulating layer is to provide an insulating layer that covers the first wiring.

[0010] The step of forming the support layer is to form a support layer that is higher than the insulating layer on the piezoelectric substrate;

[0011] The step of forming the second wiring: forming a second wiring in the region above the insulating layer to laterally connect to the support layer; and

[0012] The step of forming the cover layer: Before or after the formation of the second wiring, a cover layer that hermetically seals the resonator is formed on the support layer.

[0013] In one embodiment of this disclosure, during the step of forming the second wiring, the second wiring intersects the first wiring three-dimensionally.

[0014] In one embodiment of this disclosure, the step of forming the second wiring is performed after the step of forming the cover layer, and the step of forming the second wiring further includes pushing metal into a hole in the cover layer and providing the metal to a region above the insulating layer.

[0015] In one embodiment of this disclosure, during the step of forming the second wiring, the metal is provided through at least two holes in the cover layer to the region above the insulating layer.

[0016] In one embodiment of this disclosure, in the step of forming the second wiring, the metal is solder, and the method for manufacturing the elastic surface wave device further includes solder reflow soldering and flux cleaning of the metal provided to the upper region of the insulating layer.

[0017] In one embodiment of this disclosure, the step of forming the second wiring is performed after the step of forming the cover layer, and the step of forming the second wiring further includes providing metal to the region above the insulating layer through an opening in a metal mask before forming the cover layer.

[0018] In one embodiment of this disclosure, in the step of forming the second wiring, the metal is solder, and the method for manufacturing the elastic surface wave device further includes the steps of reflow soldering and flux cleaning: solder reflow soldering and flux cleaning are performed on the metal provided to the upper region of the insulating layer, and after the steps of reflow soldering and flux cleaning, the step of forming the cover layer is performed.

[0019] In one embodiment of this disclosure, during the step of forming the cover layer, the cover layer located directly above the region where the first wiring and the insulating layer are formed is not provided with holes.

[0020] One form of this disclosure also includes:

[0021] The step of forming the through hole: forming a through hole through the support layer and the cover layer in the area formed by the external connection pads; and

[0022] The step of forming an external connection terminal is as follows: an external connection terminal is formed in the through hole;

[0023] In the step of forming the external connection terminal, a first mask with several holes is used, and in the step of forming the second wiring, a second mask with several holes smaller than those of the first mask is used.

[0024] One form of this disclosure also includes:

[0025] The step of forming the through hole: forming a through hole through the support layer and the cover layer in the area formed by the external connection pads; and

[0026] Step of forming external connection terminals: Form external connection terminals in the through hole;

[0027] The steps for forming external connection terminals and forming the second wiring are the same process.

[0028] In one embodiment of this disclosure, a step of forming substrate wiring is further included: after the step of forming an insulating layer and before the step of forming a second wiring, substrate wiring that intersects the first wiring in a three-dimensional manner is formed on the insulating layer.

[0029] In one embodiment of this disclosure, the second wiring is formed after the substrate wiring has formed a base metal layer.

[0030] In one embodiment of this disclosure, during the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring; this disclosure further includes a step of forming a base metal layer on the substrate wiring and the insulating layer after the step of forming the insulating layer and before the step of forming the second wiring.

[0031] In one embodiment of this disclosure, during the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring; this disclosure further includes a step of forming a base metal layer on the substrate wiring after the step of forming an insulating layer and before the step of forming the second wiring.

[0032] The beneficial effect of the present invention is that, according to this disclosure, a method for manufacturing an elastic surface wave device with thick wiring can be provided. Attached Figure Description

[0033] Figure 1 This is a cross-sectional view of the elastic surface wave device of the first embodiment.

[0034] Figure 2 This is a top view of the elastic surface wave device of the first embodiment.

[0035] Figure 3 This is a cross-sectional view of the elastic surface wave device of the first embodiment.

[0036] Figure 4 This is a cross-sectional view of the elastic surface wave device of the second embodiment.

[0037] Figure 5 This is a cross-sectional view of the elastic surface wave device according to the third embodiment.

[0038] Figure 6 This is a flowchart of the manufacturing method of the elastic surface wave device according to the fourth embodiment.

[0039] Figure 7 This is a cross-sectional view of the elastic surface wave device during the formation of the second wiring process.

[0040] Figure 8 This is a cross-sectional view of the elastic surface wave device during the formation of the second wiring process.

[0041] Figure 9 This is a cross-sectional view of the elastic surface wave device during the formation of the second wiring process.

[0042] Figure 10 This is a flowchart of a method for manufacturing an elastic surface wave device according to another embodiment.

[0043] Figure 11 This is a flowchart of a method for manufacturing an elastic surface wave device according to another embodiment.

[0044] Figure 12 This is a flowchart of a method for manufacturing an elastic surface wave device according to another embodiment.

[0045] Figure 13 This is a cross-sectional view of an elastic surface wave device that provides a second wiring material before forming the cover layer. Detailed Implementation

[0046] The specific embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the same or equivalent parts in each figure are labeled with the same reference numerals. The descriptions of the same or equivalent parts will be appropriately simplified or omitted.

[0047] (First Embodiment)

[0048] Figure 1 This is a cross-sectional view of the elastic surface wave device 10 in the first embodiment. The elastic surface wave device 10 includes a piezoelectric substrate 12. As an example, the piezoelectric substrate 12 is made of lithium tantalate (LiTaO3), lithium niobate (LiNbO3), quartz (SiO2), lithium borate (Li2B4O7), zinc oxide (ZnO), potassium niobate (KNbO3), or lanthanum gallium silicate (La3Ga3SiO2). 14 It is made of piezoelectric ceramics or piezoelectric ceramics.

[0049] The piezoelectric substrate 12 is provided with several resonators. For example... Figure 1IDTs 15a and 15b, which are formed as part of the resonator, are shown. As an example, the resonator comprises an IDT that excites elastic surface waves and a reflector. The IDT has a pair of opposing comb electrodes. The comb electrodes have several electrode fingers and bus bars connecting the electrode fingers. The reflector may be disposed on both sides of the IDT.

[0050] As an example of wiring, a first wiring 14a, a lower wiring 14b, and a substrate wiring 14c are formed on the piezoelectric substrate 12. For example, the first wiring 14a is electrically connected to at least one of the resonators.

[0051] An insulating layer 16 is provided on the first wiring 14a. As an example, the insulating layer 16 connects the upper surface and the side surface of the first wiring 14a. Therefore, the insulating layer 16 also connects to the piezoelectric substrate 12.

[0052] A support layer 22 is provided in the area on the piezoelectric substrate 12 outside the formation region of the resonator. A cover layer 24 is provided on the support layer 22. The resonator containing the IDT 15a is hermetically sealed by the piezoelectric substrate 12, the support layer 22, and the cover layer 24, thereby forming a cavity 26a. The resonator containing the IDT 15b is hermetically sealed by the piezoelectric substrate 12, the support layer 22, and the cover layer 24, thereby forming a cavity 26b. The cover layer 24 hermetically seals the resonator.

[0053] The upper surface and side surfaces of the insulating layer 16 are covered with substrate wiring 14c. The substrate wiring 14c is wiring formed on the insulating layer 16 and the piezoelectric substrate 12. A second wiring 20a is disposed on the substrate wiring 14c through an intermediate layer 18a of conductive material. In this example, a thick wiring can be provided through the substrate wiring 14c, the intermediate layer 18a, and the second wiring 20a. In other examples, the intermediate layer 18a may be omitted.

[0054] The lower surface of the second wiring 20a is connected to the substrate wiring 14c via or without the intermediate layer 18a. The side surface of the second wiring 20a is connected to the side surface of the support layer 22. In other words, the top view shape of the second wiring 20a is defined by the support layer 22.

[0055] The area formed by the second wiring 20a is not provided with the support layer 22. For example... Figure 1 As shown, the area formed by the second wiring 20a is denoted by x1. The support layer 22 is not disposed within the range of x1.

[0056] The first wiring 14a extends along the positive and negative y-directions. On the other hand, the substrate wiring 14c, the intermediate layer 18a, and the second wiring 20a extend along the positive and negative x-directions. In other words, the longitudinal direction of the first wiring 14a is parallel to the y-axis. Furthermore, the longitudinal directions of the substrate wiring 14c, the intermediate layer 18a, and the second wiring 20a are parallel to the x-axis. Therefore, the second wiring 20a is formed on the insulating layer 16 and intersects the first wiring 14a three-dimensionally.

[0057] The cover layer 24 forms at least two holes in the area where the second wiring 20a is disposed. For example... Figure 1 As shown, the cover layer 24 has holes 24a and 24b.

[0058] An upper wiring 20b is disposed on the lower wiring 14b via an intermediate layer 18b of conductive material. In this example, a thick wiring can be provided through the lower wiring 14b, the intermediate layer 18b, and the upper wiring 20b. In other examples, the intermediate layer 18b may be omitted.

[0059] The lower surface of the upper wiring 20b is connected to the lower wiring 14b via the intermediate layer 18b or without the intermediate layer 18b. The side surface of the upper wiring 20b is connected to the side surface of the support layer 22. The top view shape of the upper wiring 20b is defined by the support layer 22. It should be noted that the intermediate layers 18a and 18b can be, for example, used as under bump metal (UBM) or seed layers.

[0060] 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 to increase the thickness of 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 low impedance and heat dissipation of the wiring can be improved, and the dielectric strength can be enhanced. As an example, the line / spacing (L / S) of the second wiring 20a and the upper wiring 20b formed with the solder is, for example, 10 / 10 μm.

[0061] As an example, the second wiring 20a and the upper wiring 20b are located lower than the upper end of the support layer 22. Therefore, there is a gap 26c between the cover layer 24 and the second wiring 20a, and a gap 26d between the cover layer 24 and the upper wiring 20b.

[0062] Figure 2 This is a top view of the elastic surface wave device 10. Figure 1 It is along Figure 2A cross-sectional view along section line I-I'. (See attached image.) Figure 2 As shown, on the upper surface of the surface acoustic wave (WAW) device 10, external connection terminals 30 and internal wiring 39 are exposed. As an example, the external connection terminals 30 are used to receive and generate signals, and the internal wiring 39 is used to provide a ground potential. When mounting the WLP-structured WAW device 10 onto a substrate, the external connection terminals 30 and the internal wiring 39 are connected to the substrate.

[0063] exist Figure 2 In the diagram, the planar shapes of the cavities 26a and 26b, the second wiring 20a, and the upper wiring 20b are represented by dashed lines. The second wiring 20a extends along the positive and negative x-directions, and the upper wiring 20b extends along the positive and negative y-directions. The cover layer 24 directly above the second wiring 20a has the holes 24a and 24b. The cover layer 24 directly above the upper wiring 20b has a hole 24c. The holes in the cover layer 24 are much smaller than the wiring area.

[0064] Figure 3 It is along Figure 2 The image shows a cross-sectional view of the elastic surface wave device 10 along line III-III'. External connection pads 31 are formed on the piezoelectric substrate 12. As an example, the support layer 22 and the cover layer 24 have through holes 32 in the region above the external connection pads 31. The external connection terminal 30, formed in the through hole 32, can electrically connect to the external connection pads 31. The external connection terminal 30 protrudes upward from the upper surface of the cover layer 24.

[0065] As an example, the internal wiring 39 has the same shape as the external connection terminal 30. Specifically, a solder pad for connecting the internal wiring to the piezoelectric substrate 12 is provided. Above the solder pad for the internal wiring, the support layer 22 and the cover layer 24 are provided with through holes, in which the internal wiring 39 is formed. Thus, the internal wiring 39 and the solder pad for the internal wiring are electrically connected. The internal wiring 39 protrudes upward from the cover layer 24.

[0066] In reference Figures 1-3 In the described surface acoustic wave (SAW) device 10, the IDTs 15a and 15b, the first wiring 14a, the substrate wiring 14c, the lower wiring 14b, the external connection pad 31, and the internal wiring pad are thin films made of conductive materials. The conductive material can be, for example, an aluminum (Al) alloy, such as an aluminum-copper alloy (Al-Cu), a single aluminum (Al) metal, or a laminated film formed by stacking multiple conductive materials.

[0067] The line-to-spacing (L / S) of the wiring is, for example, 10 / 10 μm. For instance, the wiring having the substrate wiring 14c and the second wiring 20a has a width of 10 μm and a height of 20 μm. Similarly, the wiring having the lower wiring 14b and the upper wiring 20b has a width of 10 μm and a height of 20 μm. Thinning the support layer 22 and the cover layer 24 contributes to a lower back profile of the device. Further miniaturization of the device can be achieved by further reducing the L / S ratio to achieve a thinner profile.

[0068] As an example, the lower surface of the piezoelectric substrate 12 may be bonded to a support substrate. The support substrate may be made of, for example, sapphire, silicon, alumina, spinel, crystal, or glass.

[0069] The surface wave device 10 can be any of a filter, a resonator, a delay line, or a trap. Furthermore, the elastic waves excited by the IDTs 15a and 15b can be any of a Rayleigh wave or an SH wave. Moreover, when the surface wave device 10 is a filter, it can be one of a resonator filter or a transversal filter.

[0070] (Second Embodiment)

[0071] The elastic surface wave device of the second embodiment is similar to the first embodiment in many ways, so similar parts will be omitted, and only the parts that are different from the first embodiment will be described.

[0072] Figure 4 This is a cross-sectional view of the elastic surface wave device according to the second embodiment. Substrate wirings 14d and 14e are formed on the piezoelectric substrate 12. Above the substrate wirings 14d and 14e and the insulating layer 16, a second wiring 20c is formed, either through an intermediate layer 18c or without the intermediate layer 18c. As an example, the material of the second wiring 20c is solder. The wiring having the second wiring 20c and the substrate wirings 14d and 14e intersects the first wiring 14a in a three-dimensional manner. The second wiring 20c serves as a bridging wiring.

[0073] The lower surface of the second wiring 20c connects the substrate wirings 14d, 14e to the insulating layer 16 via an intermediate layer 18c of conductive material, or without the intermediate layer 18c. The side of the second wiring 20c connects to the side of the support layer 22. Therefore, the top view shape of the second wiring 20c is defined by the support layer 22.

[0074] In the first embodiment, the substrate wiring 14c must be formed after the first wiring 14a and the insulating layer 16 are formed, thus requiring two wiring processes. On the other hand, in the second embodiment, since it is not necessary to form substrate wiring on the insulating layer 16, the first wiring 14a and substrate wirings 14d and 14e can be formed in a single process. Therefore, the process can be simplified.

[0075] (Third Embodiment)

[0076] The elastic surface wave device of the third embodiment is similar to the second embodiment in many ways, so similar parts will be omitted, and only the parts that are different from the second embodiment will be described.

[0077] Figure 5 This is a cross-sectional view of the elastic surface wave device according to the third embodiment. The second wiring serves as a bridging wiring. An intermediate layer 18d is provided on the substrate wirings 14d and 14e, but no intermediate layer is provided on the insulating layer 16. Therefore, the lower surface of the second wiring 20d is connected to the substrate wirings 14d and 14e through the conductive intermediate layer 18d, and is also connected to the insulating layer 16. The side surface of the second wiring 20d is connected to the side surface of the support layer 22.

[0078] 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, because the intermediate layer 18d is provided, the substrate wirings 14d, 14e and the second wiring 20d can be reliably bonded. On the other hand, by omitting the intermediate layer between the insulating layer 16 and the second wiring 20d, a low-cost and suitable device can be provided. It should be noted that when the substrate wirings 14d, 14e are bonded to the second wiring 20d, the intermediate layer 18d can also be omitted.

[0079] (Fourth Embodiment)

[0080] Figure 6 This is a flowchart of a method for manufacturing an elastic surface wave device according to the fourth embodiment. First, in step S1, a plurality of resonators, external connection pads 31, and a first wiring 14a electrically connecting at least one of the resonators are formed on the piezoelectric substrate 12. Other structures may also be formed in step S1. For example, in addition to the components described above, a lower wiring 14b and an internal wiring pad may also be formed in step S1. As an example, the resonators, external connection pads 31, first wiring 14a, lower wiring 14b, and internal wiring pads are formed in the same process.

[0081] In manufacturing such Figure 4In the case of the elastic surface wave device shown, in step S1, in addition to the aforementioned components, substrate wiring 14d and 14e are also formed. In manufacturing such... Figure 5 In the case of the elastic surface wave device shown, in step S1, in addition to the above-mentioned components, a structure is also formed as shown in the figure. Figure 5 The substrate wirings 14d and 14e are shown. For example, while the resonator, the external connection pad 31, the internal wiring pad, the lower wiring 14b and the first wiring 14a are formed, the substrate wirings 14d and 14e are formed on the left and right sides of the first wiring 14a.

[0082] As an example, the conductive layer formed in this process is formed into a thin film by film deposition methods such as sputtering, evaporation, and CVD (Chemical Vapor Deposition). It is then patterned using photolithography techniques such as stepper and RIE (Reactive Ion Etching) equipment to process it into the desired shape.

[0083] Next, step S2 is performed. In step S2, the insulating layer 16 and intermediate layers 18a and 18b are formed. During manufacturing... Figure 1 In the case of a flexible surface wave device, the substrate wiring 14c is also formed. That is, in the manufacture of... Figure 1 In the case of an elastic surface wave device, the insulating layer 16 is first formed, and then substrate wiring 14c is formed on the insulating layer 16 using photolithography or similar methods. Herein, after the process of forming the insulating layer 16 and before the formation of the second wiring 20a, substrate wiring 14c that three-dimensionally intersects with the first wiring 14a is formed on the insulating layer 16. Next, an intermediate layer 18a serving as a base metal layer is formed on the substrate wiring 14c. Then, or simultaneously, the intermediate layer 18b serving as a base metal layer is formed on the lower wiring 14b.

[0084] In manufacturing Figure 4 In the case of an elastic surface wave device, the insulating layer 16 and intermediate layers 18b and 18c are formed in step S2. During manufacturing... Figure 5 In the case of an elastic surface wave device, the insulating layer 16 and intermediate layers 18b and 18d are formed in step S2. As an example, such as... Figure 4 , 5 As shown, an insulating layer 16 can be formed in a manner that covers the first wiring 14a. During manufacturing... Figure 4In the case of an elastic surface wave device, after forming the insulating layer 16, an intermediate layer 18c, serving as a base metal layer, is formed on the substrate wirings 14d, 14e and the insulating layer 16, and an intermediate layer 18b, also serving as a base metal layer, is formed on the lower wiring 14b. During manufacturing... Figure 5 In the case of an elastic surface wave device, after the insulating layer 16 is formed, an intermediate layer 18d as a base metal layer is formed on the substrate wirings 14d and 14e, and an intermediate layer 18b as a base metal layer is formed on the lower wiring 14b. Figure 1 , 4 The intermediate layers 18a, 18b, 18c, and 18d described in 5, as an example, can be set up to improve the wettability of the solder.

[0085] Next, step S3 is performed. In step S3, the support layer 22 and the cover layer 24 are formed. First, a support layer 22, which is higher than the insulating layer 16, is formed on the piezoelectric substrate 12. The support layer 22 can be formed by patterning a thin film formed on the piezoelectric substrate 12 using a general film forming method, or by laminating a separately fabricated thin film onto the piezoelectric substrate 12.

[0086] When the support layer 22 is formed using the aforementioned method, for example, the support layer 22 can be formed by patterning a thin film of photoresist using photolithography and then curing it. In this case, the photoresist can be, for example, photosensitive resins such as epoxy resins, polyimide resins, BCB (benzocyclobutene) resins, and acrylic fiber resins. The methods for forming the photoresist are represented by methods using photosensitive dry films and methods using photosensitive liquid photoresists. When using a photosensitive dry film, a vacuum lamination device can be used to tightly bond the photosensitive dry film to the wafer or substrate surface of the elastic surface wave device. When using a photosensitive dry film, a relatively thick support layer 22 with excellent adhesion, exceeding 10 μm in thickness, can be formed. When using a photosensitive liquid photoresist, it is formed, for example, by coating the photoresist liquid using spin coating or printing methods. Preferably, the photoresist is formed into a thin film using spin coating. When photoresist is formed into a thin film by spin coating, even if the underlying structure has a height difference, the photoresist film can be formed without gaps with the underlying structure, and the support layer 22 with excellent adhesion can be formed.

[0087] The photoresist film formed in the above manner undergoes exposure and development processes to be processed into a support layer 22 disposed in a region outside the formation region of the IDT. The thickness of the support layer 22 is, for example, 20 μm. Other thicknesses may be used in other embodiments.

[0088] Next, a thin film-like covering layer 24 is formed on the upper surface of the support layer 22, and the support layer 22 is bonded to the covering layer 24. The covering layer 24 provides cavities 26a and 26b, respectively, as sealed vibration spaces in the formation regions of the IDTs 15a and 15b. The covering layer 24 hermetically seals the resonator.

[0089] As an example, in order to place the cover layer 24 on the upper surface of the support layer 22, the film is pressed and bonded by a laminating machine with rollers while controlling the temperature, and the temperature and pressure are appropriately controlled to bond the cover layer 24 to the upper surface of the support layer 22.

[0090] To bond the support layer 22 to the cover layer 24, the support layer 22 and the cover layer 24 can be heated or exposed to light, depending on the selected material. For example, if the material of the support layer 22 and the cover layer 24 is epoxy resin, the support layer 22 and the cover layer 24 can be heated to 100°C. The cover layer 24 formed by the above method can seal the IDTs 15a and 15b while forming the vibration space (cavity region), thus slowing down the oxidation of the IDTs. The thickness of the cover layer 13 can be, for example, between 20 μm and 45 μm.

[0091] If the support layer 22 and the cover layer 24 are made of the same material, they can be bonded together as a single unit. Because the interface between them is made of the same material, the bonding strength and the airtightness of the cover layer 24 are improved. In particular, when both materials are epoxy resins, heating to the range of 100°C to 200°C further promotes bonding, thus enhancing the bonding strength and the airtightness of the cover layer 24.

[0092] As an example, several holes are formed in the cover layer 24. These holes in the cover layer 24 are, for example, formed directly above the area of ​​the substrate wiring and directly above the area of ​​the lower wiring 14b. In other words, the holes are formed directly above the predetermined thickened wiring area. Figure 2 In the example, the cover layer 24 forms holes 24a, 24b, and 24c. The holes 24a, 24b, and 24c of the cover layer 24 can be formed before the cover layer 24 is bonded to the support layer 22, or they can be formed after the cover layer 24 is bonded to the support layer 22.

[0093] Next, step S4 is performed. In step S4, a second wiring 20a is formed in the region above the insulating layer 16 to connect laterally to the support layer 22. At the same time, an upper wiring 20b is formed.

[0094] Figures 7-9 This is a schematic diagram illustrating the process of forming the second wiring 20a and the upper wiring 20b. First, as... Figure 7 As shown, a metal mask 40, a scraper 50, a pressurized metal paste supply head 52, and metal paste 54 are prepared. The metal mask 40 has mask openings 40a and 40b. A mask opening is also formed directly above the lower wiring 14b. The mask openings are located directly above the holes 24a, 24b, and 24c of the cover layer 24. As an example, the mask openings correspond one-to-one with the holes of the cover layer 24. In short, there is a hole in the cover layer 24 directly below each mask opening. Figure 7-9 Due to the viewing angle, only mask openings 40a and 40b and their corresponding holes 24a and 24b are shown, while hole 24c and its corresponding mask opening are not shown. As an example, the width of the mask opening is larger than the width of the hole in the cover layer 24.

[0095] exist Figure 8 In this process, by advancing the scraper 50, metal paste 54a and 54b are provided onto the intermediate layer 18a through the mask openings 40a and 40b and the holes 24a and 24b of the cover layer 24, as shown in the figure. Furthermore, by advancing the scraper 50, metal paste 54c is provided onto the intermediate layer 18b through the mask openings and the holes 24c of the cover layer 24.

[0096] Therefore, in the process of forming the second wiring, firstly, a paste-like metal (hereinafter referred to as metal) is pushed into the holes of the cover layer 24 to provide metal paste to the area above the insulating layer 16. As an example, the metal is provided to the area above the insulating layer 16 through at least two holes 24a, 24b of the cover layer 24. The metal connects the substrate wiring 14c in the absence of the intermediate layer 18a, and connects the intermediate layer 18a in the presence of the intermediate layer 18a.

[0097] After that, as Figure 9 As shown, once the metal mask 40 is removed, metal intended for forming the second wiring will remain on the intermediate layers 18a and 18b, in the holes of the cover layer 24, and above the cover layer 24. In other examples, due to the relationship between the opening area and the thickness of the metal mask, the metal is not easily detached, and therefore, metal in the metal mask will remain within the metal mask.

[0098] Next, step S5 is performed. In step S5, the external connection terminal 30 is formed. In step S5, firstly, a through hole is formed for setting the external connection pad 31 and penetrating the support layer 22 and the cover layer 24. For example, as Figure 3 The through hole 32 is formed as shown. Then, the external connection terminal 30 is formed in the through hole 32.

[0099] As an example, a first mask with several holes is used to form the external connection terminal 30. Specifically, metal material is supplied to the through-hole 32 through the mask openings of the first mask by advancing the scraper 50. As an example, a second mask with several holes smaller than those of the first mask can be provided, and the second mask can be used as a mask for forming the second wiring.

[0100] In other examples, the external connection terminal 30 and the second wiring 20a are formed in the same process. In other words, a mask opening is made in the metal mask 40 directly above the external connection pad 31. Furthermore, metal paste is supplied to the area above the insulating layer 16 through the mask opening and the holes in the cover layer 24, and metal paste, as the material of the external connection terminal 30, is supplied to the external connection pad 31 through other mask openings and the holes in the cover layer 24. It should be noted that during manufacturing... Figure 4 In the case of an elastic surface wave device of type 5, the metal paste is also provided in the same manner as described above.

[0101] Next, step S6 is performed. In step S6, the paste metal is shaped into the second wirings 20a, 20c, 20d and the upper wiring 20b by reflow soldering. As an example, the metal provided to the region above the insulating layer 16 and the metal provided to the region above the intermediate layer 18b are solders. By performing a solder reflow soldering and flux cleaning process on the solder, a solution such as... can be provided. Figure 1 , 4 The second wiring 20a, 20c, 20d shown in Figure 5 is the upper wiring 20b. Therefore, the second wiring 20a, 20c, 20d can be provided to intersect the first wiring 14a three-dimensionally.

[0102] Reference Figure 6 The manufacturing method described includes providing metal paste in step S4, providing metal paste in step S5, and performing reflow soldering in step S6, thus comprising two solder printing operations and one reflow soldering operation.

[0103] Figure 10 This is a flowchart of a manufacturing method for other embodiments of the elastic surface wave device. Steps S1 to S4 and Figure 6 Steps S1 to S4 described herein are the same. Figure 10 In the example, step S5 involves reflow soldering and flux cleaning to form the second wirings 20a, 20c, 20d and the upper wiring 20b. Next, in step S6, a paste metal is applied to the external connection pad 31. Then, in step S7, reflow soldering and flux cleaning are performed on the paste metal on the external connection pad 31. This forms the external connection terminal 30.

[0104] In this way, Figure 10 In the example, a reflow soldering and flux cleaning process is performed to form the second wiring and the upper wiring. Additionally, a reflow soldering and flux cleaning process is performed to form the external connection terminal 30. Therefore, the reflow soldering and flux cleaning processes can be optimized according to the manufactured component.

[0105] See Figure 10 In the manufacturing method described, metal paste is provided in step S4, reflow soldering and flux cleaning are performed in step S5, metal paste is provided in step S6, and reflow soldering and flux cleaning are performed in step S7, thus including two solder printing and two reflow soldering processes.

[0106] Figure 11 This is a flowchart of a manufacturing method for other embodiments of the elastic surface wave device. Steps S1 to S3 are referenced. Figure 6 Steps S1 through S3 are the same as described above. Figure 11 In the example, step S4 simultaneously provides metal paste for forming the second wiring and the upper wiring 20b, and metal paste for forming the external connection terminal 30, above the intermediate layer.

[0107] Next, in step S5, a reflow soldering process and a flux cleaning process are performed to form the second wiring, the upper wiring 20b, and the external connection terminal 30. (See also...) Figure 11 The manufacturing method described herein involves providing all the required metal paste at once in step S4, and forming the second wiring, upper wiring 20b, and external connection terminal 30 through the reflow soldering and flux cleaning process in step S5.

[0108] See Figure 11 In the manufacturing method described, metal paste is provided in step S4 and reflow soldering is performed in step S5, thus including one solder printing and one reflow soldering.

[0109] Figure 12 This is a flowchart of a manufacturing method for other embodiments of the elastic surface wave device. Steps S1, S2 and... Figure 6 Steps S1 and S2 described herein are the same. Figure 12In the example, the support layer 22 is formed in step S3. Then, in step S4, metal paste is provided without a cover layer.

[0110] Figure 13 This is a cross-sectional view illustrating an elastic surface wave device for providing the material of the second wiring without a cover layer. Metal paste, pushed in by the scraper 50, is provided onto the intermediate layers 18a and 18b through a mask opening. Simultaneously, metal paste, serving as the material for the external connection terminals 30, is provided onto the external connection pads 31 through other processes.

[0111] Next, in Figure 12 In step S5, reflow soldering and flux cleaning processes are performed on all the metal paste. If the metal paste is solder, the reflow soldering is a solder reflow soldering process.

[0112] then, Figure 12 In step S6, a cover layer 24 is formed on the support layer 22. Since the second wiring and the upper wiring have already been formed before the cover layer 24 is formed, it is not necessary to form holes in the cover layer 24 for the second wiring and the upper wiring. Therefore, for example, the cover layer 24 located directly above the formation area of ​​the first wiring, the insulating layer 16, the substrate wiring, and the lower wiring 14b does not have holes. Figure 2 For example, holes 24a, 24b, and 24c can be omitted. It should be noted that, according to... Figure 12 The flowchart shows that the overlay 24 has through holes to expose the external connection terminal 30 and the internal wiring 39.

[0113] See Figure 12 , 13 In the illustrated example, before forming the cover layer 24, metal is provided through the mask opening to the area above the insulating layer to form a second wiring. This increases the freedom of choice regarding the opening area of ​​the cover layer.

[0114] While at least one embodiment has been described above, it should be understood that various changes, modifications, or improvements will readily occur to those skilled in the art. These changes, modifications, or improvements are also part of this disclosure and fall within the scope of this invention.

[0115] It should be understood that the embodiments of the methods or apparatus described herein are not limited to the architecture and arrangement of the constituent components described above or illustrated in the accompanying drawings. The methods and apparatus can be installed or performed in other embodiments.

[0116] The embodiments described are for illustrative purposes only and are not intended to be limiting.

[0117] The descriptions and terms used in this disclosure are for illustrative purposes only and are not intended to be limiting. The use of "including," "possessing," "having," "comprise," and variations thereof here means to include the items listed below, their equivalents, and additional items.

[0118] The word “or”, or any word used in a description, may be interpreted as one, more than one, or all of the descriptive words.

[0119] The references to front, back, left, right, top, bottom, upper, lower, and horizontal and vertical are for ease of description and are not intended to limit the position and spatial configuration of any component in this invention. Therefore, the above description and drawings are merely exemplary.

Claims

1. A method for manufacturing an elastic surface wave device, characterized in that: The method for manufacturing the elastic surface wave device includes: The steps for forming the first wiring are: forming a plurality of resonators, external connection pads, and a first wiring that electrically connects at least one of the resonators on a piezoelectric substrate; The step of forming an insulating layer is to provide an insulating layer that covers the first wiring. The step of forming the support layer is to form a support layer that is higher than the insulating layer on the piezoelectric substrate; The step of forming the second wiring is as follows: A second wiring is formed in the region above the insulating layer to be laterally connected to the support layer; and The step of forming the cover layer: Before or after the formation of the second wiring, a cover layer that hermetically seals the resonator is formed on the support layer.

2. The method for manufacturing the elastic surface wave device according to claim 1, characterized in that: In the step of forming the second wiring, the second wiring intersects the first wiring three-dimensionally.

3. The method for manufacturing the elastic surface wave device according to claim 1 or 2, characterized in that: The step of forming the second wiring follows the step of forming the cover layer. The step of forming the second wiring further includes pushing metal into the holes of the cover layer and providing the metal to the region above the insulating layer.

4. The method for manufacturing the elastic surface wave device according to claim 3, characterized in that: In the step of forming the second wiring, the metal is provided to the area above the insulating layer through at least two holes in the cover layer.

5. The method for manufacturing the elastic surface wave device according to claim 3, characterized in that: In the step of forming the second wiring, the metal is solder, and the method of manufacturing the elastic surface wave device further includes solder reflow soldering and flux cleaning of the metal provided to the upper region of the insulating layer.

6. The method for manufacturing the elastic surface wave device according to claim 4, characterized in that: In the step of forming the second wiring, the metal is solder, and the method of manufacturing the elastic surface wave device further includes solder reflow soldering and flux cleaning of the metal provided to the upper region of the insulating layer.

7. The method for manufacturing the elastic surface wave device according to claim 1 or 2, characterized in that: The step of forming the second wiring is after the step of forming the cover layer. The step of forming the second wiring also includes providing metal to the area above the insulating layer through an opening in the metal mask before forming the cover layer.

8. The method for manufacturing the elastic surface wave device according to claim 7, characterized in that: In the step of forming the second wiring, the metal is solder, and the manufacturing method of the elastic surface wave device further includes the steps of reflow soldering and flux cleaning: solder reflow soldering and flux cleaning are performed on the metal provided to the upper region of the insulating layer, and after the steps of reflow soldering and flux cleaning, the step of forming the cover layer is performed.

9. The method for manufacturing the elastic surface wave device according to claim 8, characterized in that: In the step of forming the cover layer, the cover layer located directly above the area where the first wiring and the insulating layer are formed is not provided with holes.

10. The method for manufacturing the elastic surface wave device according to claim 1 or 2, characterized in that: The method for manufacturing the elastic surface wave device further includes: The step of forming the through hole: forming a through hole through the support layer and the cover layer in the area formed by the external connection pads; and The step of forming an external connection terminal is as follows: an external connection terminal is formed in the through hole; In the step of forming the external connection terminal, a first mask with several holes is used, and in the step of forming the second wiring, a second mask with several holes smaller than those of the first mask is used.

11. The method for manufacturing the elastic surface wave device according to claim 1, characterized in that: The method for manufacturing the elastic surface wave device further includes: The step of forming a through hole: forming a through hole through the support layer and the cover layer in the area formed by the external connection pads; and Step of forming external connection terminals: Form external connection terminals in the through hole; The steps for forming external connection terminals and forming the second wiring are the same process.

12. The method for manufacturing the elastic surface wave device according to claim 1, characterized in that: The method for manufacturing the elastic surface wave device further includes the step of forming substrate wiring: after the step of forming an insulating layer and before the step of forming a second wiring, substrate wiring that intersects the first wiring in a three-dimensional manner is formed on the insulating layer.

13. The method for manufacturing the elastic surface wave device according to claim 12, characterized in that: In the step of forming the second wiring, the second wiring is formed after the substrate wiring forms a base metal layer.

14. The method for manufacturing the elastic surface wave device according to claim 5, characterized in that: In the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring; the method for manufacturing the elastic surface wave device further includes: after the step of forming the insulating layer and before the step of forming the second wiring, forming a base metal layer on the substrate wiring and the insulating layer.

15. The method for manufacturing the elastic surface wave device according to claim 6, characterized in that: In the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring; the method for manufacturing the elastic surface wave device further includes: after the step of forming the insulating layer and before the step of forming the second wiring, forming a base metal layer on the substrate wiring and the insulating layer.

16. The method for manufacturing the elastic surface wave device according to claim 8, characterized in that: In the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring; the method for manufacturing the elastic surface wave device further includes: after the step of forming the insulating layer and before the step of forming the second wiring, forming a base metal layer on the substrate wiring and the insulating layer.

17. The method for manufacturing the elastic surface wave device according to claim 5, characterized in that: In the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring. The method for manufacturing the elastic surface wave device further includes: after the step of forming an insulating layer and before the step of forming the second wiring, a step of forming a base metal layer on the substrate wiring.

18. The method for manufacturing the elastic surface wave device according to claim 6, characterized in that: In the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring. The method for manufacturing the elastic surface wave device further includes: after the step of forming an insulating layer and before the step of forming the second wiring, a step of forming a base metal layer on the substrate wiring.

19. The method for manufacturing the elastic surface wave device according to claim 8, characterized in that: In the step of forming the first wiring, substrate wiring is formed on the left and right sides of the first wiring simultaneously with the formation of the first wiring. The method for manufacturing the elastic surface wave device further includes: after the step of forming an insulating layer and before the step of forming the second wiring, a step of forming a base metal layer on the substrate wiring.

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