Elastic wave device and method for manufacturing same

Abstract

The present application relates to an elastic wave device and a method for manufacturing the same, the elastic wave device including a device chip including a plurality of functional elements including at least an IDT electrode on one surface, a thick film wiring having a thickness greater than that of the functional elements, and a surrounding metal layer surrounding a region where the functional elements and the thick film wiring are formed and having the same thickness as that of the thick film wiring; the thin film layer is made of an insulating material or a high-resistance material and is formed on the thick film wiring and the surrounding metal layer; the top cover substrate is jointed to the thick film wiring and the surrounding metal layer through a thin film layer, and forms a sealed space for hermetically sealing the functional element with the device chip and the surrounding metal layer; according to the elastic wave device, the top cover substrate is made of high-resistance silicon, ceramic or glass, and in the elastic wave device with the WLP structure, certain resistance to the molding pressure can be maintained, the thickness can be reduced as much as possible, and TCF characteristics and heat dissipation performance can be reasonably improved.

Description

Technical Field

[0001] The present application relates to improvements in elastic wave devices suitable for use as frequency filters and the like in mobile communication devices and the like. Background Art

[0002] Among surface acoustic wave (SAW) devices having a WLP (Wafer Level Package) structure, there is a structure as shown in Patent Document 1.

[0003] In the device of Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-217673), a resin cover is provided on one surface of a device chip, and an IDT electrode formed on the one surface is positioned within an internal space formed by the cover. Such elastic wave devices are required to be thinner.

[0004] In addition, when constituting a module together with other devices, such an elastic wave device needs to have a certain resistance to the molding pressure of the sealing resin formed on the module substrate.

[0005] In addition, such elastic wave devices need to have improved TCF characteristics (temperature-frequency characteristics) and heat dissipation properties. Summary of the invention

[0006] The main problem to be solved by this application is how to provide a new structure and a manufacturing method thereof, which can achieve as much thinness as possible while maintaining a certain resistance to the above-mentioned molding pressure in the elastic wave device of this WLP structure, and can reasonably improve the TCF characteristics and heat dissipation.

[0007] In a first aspect, the present application provides an elastic wave device having:

[0008] A device chip having a plurality of functional elements including at least an IDT electrode on one surface, a thick film wiring thicker than the functional elements, and a surrounding metal layer surrounding the formation area of ​​the functional elements and the thick film wiring and having the same thickness as the thick film wiring;

[0009] a thin film layer, composed of an insulating material or a high resistance material, formed on the thick film wiring and the surrounding metal layer; and

[0010] A top cover substrate, bonded to the thick film wiring and the surrounding metal layer through the thin film layer, and forming a sealed space for hermetically sealing the functional element with the device chip and the surrounding metal layer;

[0011] The top cover substrate is made of high-resistance silicon, ceramic or glass.

[0012] In some of the embodiments, the thin film layer is composed of silicon.

[0013] Furthermore, the surface roughness Ra of the surface of the thin film layer in contact with the top cover substrate and the surface of the top cover substrate in contact with the thin film layer are both 0.0001 nm or more and 0.5 nm or less.

[0014] In some of the embodiments, the thick film wiring and the surrounding metal layer are composed of a conductive metal film formed by photolithography technology.

[0015] In some of the embodiments, the thickness of the top cover substrate is set to be more than twice the distance between the other side of the device chip and the surface of the thick film wiring and the surrounding metal layer that is connected to the thin film layer.

[0016] In some embodiments, the area of ​​the thick film wiring and the surrounding metal layer formation region accounts for a proportion of 25% or more and 60% or less of the area of ​​the one side of the device chip.

[0017] In some of the embodiments, the thickness of the film thickness wiring and the surrounding metal layer in a direction orthogonal to one side of the device chip is 3 μm-6 μm.

[0018] In some embodiments, the thin film layer is formed by a sputtering process.

[0019] In some of the embodiments, the device chip uses lithium tantalate or lithium niobate as the piezoelectric body.

[0020] In a second aspect, the present application provides a method for manufacturing an elastic wave device, which is suitable for manufacturing the elastic wave device described in the first aspect, comprising:

[0021] In the first step, functional elements, thick film wiring and surrounding metal layers are formed on one side of the wafer on which the device chip is to be formed;

[0022] A second step, after the first step, forming a thin film layer;

[0023] A third step, after the second step, bonding one side of the collective substrate to be formed into a top cover substrate to the thin film layer; and

[0024] The fourth step is to grind the other side of the wafer to make the wafer thinner after the third step.

[0025] In some of the embodiments, after grinding the other side of the wafer, the method further comprises:

[0026] A through hole is formed on the collective substrate; the thin film layer is removed at the bottom of the through hole; and a bump is formed in the through hole.

[0027] According to the present application, an elastic wave device having a WLP structure can be provided, which can be made as thin as possible while maintaining a certain resistance to molding pressure, and can reasonably improve TCF characteristics and heat dissipation.

[0028] The details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0030] Figure 1 is a cross-sectional structural diagram of an elastic wave device (first embodiment) according to an embodiment of the present application, showing the first embodiment in Figure 2 Cross-sectional view at the AA line.

[0031] Figure 2 yes Figure 1 Cross-sectional structure diagram at line BB in .

[0032] Figure 3 FIG. 1 is a diagram showing a structure of an example of a resonator formed on a device chip constituting the first embodiment.

[0033] Figure 4 1 is a diagram showing the structure of a circuit formed on the device chip of the first embodiment.

[0034] Figure 5 It is a cross-sectional structural diagram of a main part showing the manufacturing process of the above-mentioned first embodiment.

[0035] Figure 6 It is a cross-sectional structural diagram of a main part showing the manufacturing process of the above-mentioned first embodiment.

[0036] Figure 7 It is a cross-sectional structural diagram of a main part showing the manufacturing process of the above-mentioned first embodiment.

[0037] Figure 8 It is a cross-sectional structural diagram of a main part showing the manufacturing process of the above-mentioned first embodiment.

[0038] Fig. 9 It is a cross-sectional structural diagram of a main part showing the manufacturing process of the above-mentioned first embodiment.

[0039] Fig.10 It is a cross-sectional structural diagram of a main part showing the manufacturing process of the above-mentioned first embodiment.

[0040] Fig.11 FIG. 1 is a cross-sectional structural diagram of an elastic wave device in a second embodiment, wherein a portion of the structure of the elastic wave device is different from that of the first embodiment.

[0041] In the figure: 1, elastic wave device; 1a, surface of elastic wave device; 1b, side of elastic wave device; 2, device chip; 2a, one side of device chip; 2b, side of device chip; 2c, outer edge of device chip; 2d, functional surface of device chip; 2e, other side of device chip; 3, functional element; 3a, 3aa, 3ab, resonator; 3b, IDT electrode; 3c, reflector; 3d, electrode finger; 3e, bus bar; 3f, electrode finger; 3g, bus bar; 4, thick film wiring; 4a, base layer; 4b, upper layer; 4c, back side; 4 d, front side; 4e, side; 5, surrounding metal layer; 5a, base layer; 5b, upper layer; 5c, back side; 5d, front side; 5e, side; 6, thin film layer; 7, top cover substrate; 7a, inner surface; 7b, outer surface; 7c, through hole; 8, bump; 9, sealed space; 10, signal input and output terminals; 11, circuit; 12, grounding; 13, chip; 13a, one side of the chip; 13b, the other side; 14, collective substrate; 14a, one side; 14b, thickness; 15, workpiece; X, propagation direction; L1, L2, L3, distance. DETAILED DESCRIPTION

[0042] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0043] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0044] The following is based on Figures 1 to 11 A typical embodiment of the present application will be described below. The elastic wave device 1 of this embodiment is suitable for use as a frequency filter in mobile communication equipment and the like.

[0045] The elastic wave device 1 includes a device chip 2 , a functional element 3 , a thick-film wiring 4 , a surrounding metal layer 5 , a thin-film layer 6 , a top cover substrate 7 , and bumps 8 for external connection.

[0046] Functional elements 3 and thin film wiring (not shown) are formed on one side 2a of the device chip 2. Thick film wiring 4 and surrounding metal layer 5 are also formed on one side 2a of the device chip 2. The thickness of the thick film wiring 4 and surrounding metal layer 5 in the direction orthogonal to the one side 2a of the device chip 2 is greater than that of the functional elements 3 and thin film wiring (not shown). The thickness of the thick film wiring 4 is equal to that of the surrounding metal layer 5.

[0047] In the example shown in the figure, the thick film wiring 4 and the surrounding metal layer 5 are formed by laminating upper layers 4 b and 5 b on base layers 4 a and 5 a having the same thickness as the functional element 3 .

[0048] The surrounding metal layer 5 is formed slightly inside the outer edge 2c of the device chip 2, and the outer edge 2c is formed by the connection between the one side 2a and the side surface 2b of the device chip 2. The surrounding metal layer 5 is in the shape of a quadrilateral frame when viewed from a direction perpendicular to the one side 2a of the device chip 2. The area inside the surrounding metal layer 5 formed on the one side 2a of the device chip 2 is formed as the functional surface 2d of the device chip 2 (the surface that exerts the function of the elastic wave device 1).

[0049] A plurality of functional elements 3 are formed on the functional surface 2 d of the device chip 2 .

[0050] Thick film wiring 4 is formed at a desired position on the functional surface 2d of the device chip 2, such as between adjacent functional elements 3. The thick film wiring 4 is connected to the functional element 3 via a thin film wiring (not shown) or the like.

[0051] The cover substrate 7 is indirectly bonded to and supported on the thick film wiring 4 and the surrounding metal layer 5 via a thin film layer 6 described later. The cover substrate 7 is supported on the thick film wiring 4 and the surrounding metal layer 5 in such a manner that its inner surface 7a faces one surface 2a of the device chip 2.

[0052] On one side 2a of the device chip 2, a sealed space 9 (cavity, hollow structure) is formed by the functional surface 2d, the surrounding metal layer 5 and the top cover substrate 7, and a resonator 3a described later constituting the functional element 3 is arranged in the sealed space 9.

[0053] The thick film wiring 4 can also be used as a spacer to support the top cover substrate 7 in the sealed space 9 .

[0054] Typically, the device chip 2 is configured in a quadrilateral plate shape (rectangular in the illustrated example) with a side of 0.5 mm to 1 mm and a thickness of 0.02 mm (20 μm) or more and 0.1 mm (100 μm) or less.

[0055] Typically, the functional element 3 is configured so that the thickness in the direction perpendicular to the one surface 2a of the device chip 2 (the height of the functional element 3 based on the one surface 2a of the device chip 2) is 0.1 μm to 0.5 μm.

[0056] Typically, the thickness of the thick film wiring 4 and the surrounding metal layer 5 in the direction perpendicular to the one surface 2 a of the device chip 2 is 3 μm to 6 μm.

[0057] Typically, the thickness of the top cover substrate 7 is set to 100 μm to 150 μm.

[0058] Typically, the thickness of elastic wave device 1 having the above structure is between 150 μm and 200 μm.

[0059] The elastic wave device 1 has a square or rectangular quadrilateral outline when viewed from a direction perpendicular to the one surface 2 a of the device chip 2 .

[0060] That is, the elastic wave device 1 has a flat hexahedral shape and includes the two quadrilateral faces 1 a and four side faces 1 b connecting the two faces 1 a .

[0061] In each drawing, in order to facilitate understanding of the structure of the elastic wave device 1 , the thicknesses of its components are exaggerated.

[0062] The device chip 2 has the function of propagating elastic waves. Typically, in this embodiment, the device chip 2 uses lithium tantalate or lithium niobate as a piezoelectric body. In addition, in other embodiments, the device chip 2 may also be formed by stacking lithium tantalate or lithium niobate with sapphire, silicon, aluminum oxide, spinel, quartz or glass.

[0063] Figure 3 An example of the structure of a resonator 3a as a functional element 3 is shown. The resonator 3a has an IDT electrode 3b and a reflector 3c formed by sandwiching the IDT electrode 3b. The IDT electrode 3b is composed of an electrode pair, and each electrode pair connects a plurality of electrode fingers 3d arranged in parallel to each other at one end through a bus bar 3e so that the length direction of each electrode pair intersects with the propagation direction x of the elastic wave. The reflector 3c connects the ends of a plurality of electrode fingers 3f arranged in parallel through a bus bar 3g so that the length direction of the reflector 3c intersects with the propagation direction x of the elastic wave.

[0064] Typically, the functional element 3 is composed of a conductive metal film formed using a photolithography technique.

[0065] like Figure 1 and Figure 2 As shown, the thick film wiring 4 and the surrounding metal layer 5 are formed on the above-mentioned one side 2a of the above-mentioned device chip 2, and have a predetermined thickness greater than that of the functional element 3 at any position.

[0066] In the example shown in the figure, the signal input / output terminals 10 are formed at four corners of the device chip 2 through thick film wirings 4 .

[0067] Typically, the thick film wiring 4 and the surrounding metal layer 5 are also composed of a conductive metal film formed by photolithography technology.

[0068] Figure 4FIG. 1 shows a conceptual example of a circuit 11 formed on a device chip 2 by a functional element 3, a thin film wiring (not shown), and a thick film wiring 4. Reference numeral 3aa denotes a resonator 3a connected in series between the signal input / output terminals 10, reference numeral 3ab denotes a resonator 3a connected in parallel between the signal input / output terminals 10, and reference numeral 12 denotes a ground. The number and arrangement of the resonators 3a may be changed as required. That is, by Figure 4 The circuit constitutes a ladder filter.

[0069] The cover substrate 7 has an inner surface 7a and an outer surface 7b parallel to one side 2a of the device chip 2. In the example shown in the figure, the cover substrate 7 is in the shape of a plate and has substantially the same shape and size as the device chip 2. A gap is formed between the inner surface 7a of the cover substrate 7 and one side 2a of the device chip 2. The thickness of the gap is the thickness of the thick film wiring 4 and the surrounding metal layer 5 plus the thickness of the thin film layer 6 described later. The gap is hermetically sealed by the cover substrate 7 to form the sealed space 9.

[0070] On the thick film wiring 4 and the surrounding metal layer 5, a thin film layer 6 made of an insulating material or a high resistance material is formed.

[0071] In the illustrated example, the thin film layer 6 is formed on: the front side 4d opposite to the back side 4c of the thick film wiring 4 that is in contact with one side 2a of the device chip 2; the side surface 4e between the back side 4c and the front side 4d; and a portion outside the formation area of ​​the functional element 3 in one side 2a of the device chip 2.

[0072] In addition, the thin film layer 6 is formed on: a surface 5d opposite to the back side 5c of the surrounding metal layer 5 that is in contact with one side 2a of the device chip 2; a side surface 5e between the back side 5c and the surface 5d; and a portion outside the formation area of ​​the functional element 3 in one side 2a of the device chip 2.

[0073] Typically, the thin film layer 6 is formed by sputtering.

[0074] The cover substrate 7 is indirectly bonded to the thick film wiring 4 and the surrounding metal layer 5 via the thin film layer 6. The cover substrate 7 is formed together with the device chip 2 and the surrounding metal layer 5 to form a sealed space 9 for hermetically sealing the functional element 3.

[0075] Furthermore, in the present embodiment, the top cover substrate 7 is made of high-resistance silicon, ceramics or glass.

[0076] In the example shown in the figure, through holes 7c are formed on the cover substrate 7 on the signal input / output terminals 10 of the thick film wiring 4 at the four corners of the device chip 2, the signal input / output terminals 10 are located at the bottom of the through holes 7c, and bumps 8 made of a conductive material are formed in the through holes 7c. Typically, the through holes 7c are formed by dry etching.

[0077] One end of the bump 8 is fixed to the signal input / output terminal 10, and the other end protrudes outward from the outer surface 7b of the cover substrate 7. In the signal input / output terminal 10, the thin film layer 6 is usually removed from the front surface 4d of the thick film wiring 4.

[0078] The thin film layer 6 is made of an insulating material or a high-resistance material, and the top cover substrate 7 is also made of an insulating material or a high-resistance material, so the circuit 11 is electrically connected to the outside only through the bumps 8 .

[0079] The Young's modulus of lithium tantalate is 203 GPa, the Young's modulus of silicon is 160 GPa, and the Young's modulus of glass is 66 GPa, all of which are greater than the Young's modulus of synthetic resin.

[0080] The thermal conductivity of silicon is 160 W / m K, and the thermal conductivity of ceramics is 30 W / m K to 100 W / m K, both of which are higher than the thermal conductivity of synthetic resins.

[0081] The top cover substrate 7 is made of glass, high-resistance silicon or ceramics, which can effectively improve the rigidity of the elastic wave device 1. As a result, the thickness of the device chip 2 can be reduced as much as possible, making it thinner. The top cover substrate 7 made of glass, high-resistance silicon or ceramics can reduce the thickness of the device chip 2 as much as possible, and when the entire elastic wave device 1 is mounted on a module substrate together with other devices to form a module, it can also generate a certain resistance to the molding pressure of the sealing resin formed on the module substrate.

[0082] Therefore, elastic wave device 1 can also be appropriately thinned.

[0083] In addition, the cover substrate 7 is made of high-resistance silicon, ceramics, or glass, and has a smaller thermal expansion coefficient than the device chip 2, which can suppress the dimensional change caused by the temperature change of the device chip 2. In addition, the cover substrate 7 can reduce the thickness of the device chip 2 as much as possible, thereby suppressing the above-mentioned dimensional change, thereby effectively improving the TCF characteristics (frequency temperature characteristics) of the elastic wave device 1.

[0084] Furthermore, an effective heat dissipation path can be ensured by top cover substrate 7 and thick film wiring 4 and surrounding metal layer 5 that support the top cover substrate, and the heat dissipation of elastic wave device 1 can be appropriately improved.

[0085] The manufacturing process of the elastic wave device 1 (see Figures 5 to 10), a collective substrate 14 to form a top cover substrate 7 is stacked on one side 13a of a wafer 13 to form a device chip 2. In this state, the rigidity of the collective substrate 14 can be utilized to grind the other side 13b of the wafer 13 without hindrance, so as to appropriately thin the wafer 13, i.e., the device chip 2 of the elastic wave device 1 finally generated.

[0086] In addition, in this manufacturing process, after the collective substrate 14 is stacked on the wafer 13 as described above, the workpiece 15 (object to be processed) is given a predetermined rigidity by the collective substrate 14 , thereby making it easier to increase the diameter of the wafer 13 .

[0087] As a preferred embodiment, the thin film layer 6 is made of silicon, and the surface of the thin film layer 6 in contact with the top cover substrate 7 and the inner surface 7a of the top cover substrate 7 in contact with the thin film layer 6 have a surface roughness Ra of greater than 0.0001 nm and less than 0.5 nm.

[0088] In the manufacturing process of the elastic wave device 1, the collective substrate 14 to be formed as the top cover substrate 7 is stacked on one side 13a of the wafer 13 to be formed as the device chip 2, and in this state, it is pressed with a specified force so that the thin film layer 6 can be directly bonded to the collective substrate 14.

[0089] like Fig.11 As shown, as a preferred embodiment, the thickness L1 of the top cover substrate 7 is set to be more than twice the distance L2 between the other surface 2e opposite to one surface 2a of the device chip 2 and the front surface 4d, 5d, and the front surface 4d, 5d is the surface of the thick film wiring 4 and the surrounding metal layer 5 that is in contact with the thin film layer 6.

[0090] In a preferred embodiment, the area ratio of the thick film wiring 4 and the surrounding metal layer 5 formation region to the area of ​​the one side 2 a of the device chip 2 is set to be 25% or more and 60% or less.

[0091] If the above ratio is less than 25%, the contact area between the top cover substrate 7 and the thick film wiring 4 and the surrounding metal layer 5 will be too small, and there is a risk of peeling off the top cover substrate 7 when grinding the other side 13b of the wafer 13 described later. On the other hand, if the above ratio exceeds 60%, the formation area of ​​the functional element 3 will become too narrow.

[0092] Next, based on Figures 5 to 10 , a method for manufacturing the elastic wave device 1 will be described.

[0093] First, the functional element 3, the thick film wiring 4 and the surrounding metal layer 5 are formed on one side 13a of the wafer 13 on which the device chip 2 is to be formed. Figure 5 / First step) That is, in the wafer 13, the functional element 3, the thick film wiring 4, and the surrounding metal layer 5 are formed in each region of the device chip 2 as one elastic wave device 1.

[0094] Next, the thin film layer 6 ( Figure 6 / second step).

[0095] Next, one side 14a of the assembly substrate 14 to be formed into the top cover substrate 7 is bonded to the thin film layer 6 ( Figure 7 / Third step).

[0096] Specifically, the thick film wiring 4 and the surrounding metal layer 5 are sandwiched between the wafer 13 and the collective substrate 14 , and in this state, the collective substrate 14 is stacked on the wafer 13 and pressed with a predetermined force.

[0097] Next, the other side 13b of the wafer 13 is ground (wafer thinning process) to make the wafer 13 thinner ( Figure 8 / Step 4). Figure 8 A portion of the wafer 13 removed by grinding is indicated by a two-dot chain line.

[0098] Typically, a wafer 13 having a thickness in the range of 200 μm to 400 μm is prepared, and in the fourth step, the other surface 13 b of the wafer 13 is ground until the thickness of the wafer 13 is in the range of 20 μm to 100 μm.

[0099] As a preferred embodiment, in the fourth step, the other side of the chip 13 is ground to make the chip 13 thinner until the thickness 14b of the collective substrate 14 becomes more than twice the distance L3 between the other side 13b of the chip 13 and the front side 4d, 5d, which are the surfaces of the thick film wiring 4 and the surrounding metal layer 5 that are in contact with the thin film layer 6.

[0100] Next, a through hole 7c for the bump 8 is formed on the assembly substrate 14, and the thin film layer 6 is removed at the bottom of the through hole 7c to form the bump 8 in the through hole 7c ( Fig. 9 / Step 5).

[0101] Next, the workpiece 15 obtained in the fifth step is cut into pieces in a predetermined manner, and a plurality of elastic wave devices 1 ( Fig.10 / Step 6).

[0102] The expressions and terms used in this application are for illustrative purposes only and should not be considered as limiting. The use of "include", "have", "have", "include" and their variations as used herein means including the following listed items, their equivalents and additional items.

[0103] The term "embodiment" in this application refers to a specific feature, structure or characteristic described in conjunction with the embodiment that can be included in at least one embodiment of the present application. The appearance of this phrase in various locations in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. It is clearly or implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.

[0104] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations, corrections and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. An elastic wave device, characterized in that: have: A device chip having a plurality of functional elements including at least an IDT electrode on one surface, a thick film wiring thicker than the functional elements, and a surrounding metal layer surrounding the formation area of ​​the functional elements and the thick film wiring and having the same thickness as the thick film wiring; a thin film layer, composed of an insulating material or a high resistance material, formed on the thick film wiring and the surrounding metal layer; as well as A top cover substrate, bonded to the thick film wiring and the surrounding metal layer through the thin film layer, and forming a sealed space for hermetically sealing the functional element with the device chip and the surrounding metal layer; The top cover substrate is made of high-resistance silicon, ceramic or glass.

2. The elastic wave device according to claim 1, characterized in that: The thin film layer is composed of silicon, Furthermore, the surface roughness Ra of the surface of the thin film layer in contact with the top cover substrate and the surface of the top cover substrate in contact with the thin film layer are both 0.0001 nm or more and 0.5 nm or less.

3. The elastic wave device according to claim 1, characterized in that: The thick film wiring and the surrounding metal layer are composed of a conductive metal film formed by photolithography technology.

4. The elastic wave device according to claim 1, characterized in that: The thickness of the cover substrate is set to be at least twice the distance between the other surface of the device chip and the surface of the thick film wiring and the surrounding metal layer that is in contact with the thin film layer.

5. The elastic wave device according to claim 1, characterized in that: The area of ​​the thick film wiring and the surrounding metal layer formation region accounts for a ratio of 25% to 60% of the area of ​​the one side of the device chip.

6. The elastic wave device according to claim 1, characterized in that: The thickness of the film thickness wiring and the surrounding metal layer in a direction orthogonal to one side of the device chip is 3 μm-6 μm.

7. The elastic wave device according to claim 1, characterized in that: The thin film layer is formed by a sputtering process.

8. The elastic wave device according to claim 1, characterized in that: The device chip uses lithium tantalate or lithium niobate as a piezoelectric body.

9. A method for manufacturing an elastic wave device, suitable for manufacturing the elastic wave device according to any one of claims 1 to 8, characterized in that: include: In the first step, functional elements, thick film wiring and surrounding metal layers are formed on one side of the wafer on which the device chip is to be formed; A second step, after the first step, forming a thin film layer; A third step, after the second step, bonding one side of the collective substrate to be formed into a top cover substrate to the thin film layer; as well as The fourth step is to grind the other side of the wafer to make the wafer thinner after the third step.

10. The method for manufacturing an elastic wave device according to claim 9, wherein: After grinding the other side of the wafer, the method further comprises: A through hole is formed on the collective substrate; the thin film layer is removed at the bottom of the through hole; and a bump is formed in the through hole.

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