Acoustic wave device, method of manufacturing the same, and module including the same

Abstract

To secure package reliability of an acoustic wave device while improving identification efficiency of a pin position.SOLUTION: The semiconductor device includes a device chip 100, a plurality of external connection terminals 200, a roof layer 300, and a support layer 400. The support layer 400 is formed between the principal surface of the chip 100 and the one surface 300a of the roof layer 300, and supports the roof layer 300. The external connection terminal 200 is formed in a through hole penetrating the support layer 400 and the roof layer 300, and is connected to the main surface of the device chip 100. A multi-point identification pattern P is formed on the 300a of the surface opposite to the 300b of the one surface of the roof layer 300, the multi-point identification pattern P allowing one of the plurality of external connection terminals 200 to be recognized as an identification target connection terminals in distinction from the other external connection terminals 200. The multi-point identification pattern P includes at least two dot-like patterns P1, and the dot-like pattern P1 is formed as a blind hole 300b formed on the opposite side P2 of the roof layer 300.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to the field of semiconductor packaging technology, and more particularly to an acoustic wave device in wafer level packaging (WLP) technology, a manufacturing method thereof, and a module including the acoustic wave device. [Background technology]

[0002] In WLP technology, to facilitate identification and mounting, it is common to arrange bump pads on the acoustic wave device asymmetrically or to form a metal film of a predetermined shape on the roof layer of the chip to serve as a mark indicating the pin position on the acoustic wave device chip.

[0003] However, in some acoustic wave device products, asymmetric arrangement of bump pads is difficult due to technical limitations, and forming a metal film of a predetermined shape on the roof layer increases the number of steps in the manufacturing process.

[0004] Patent Document 1 discloses a technique for marking a sealing member of an acoustic wave device using a laser beam. This method has the advantage that it can be carried out relatively easily and that marking efficiency can be ensured.

[0005] However, laser marking can cause significant damage to acoustic wave devices. Specifically, the depth of the recesses formed by marking typically exceeds 10 μm, which adversely affects the reliability of the packaging of acoustic wave devices.

[0006] As described above, it is difficult to improve the pin position identification efficiency while simultaneously ensuring package reliability in the sealing process of an acoustic wave device, and no effective solution to this problem has been proposed to date. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2017 / 033575 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide an acoustic wave device and a manufacturing method thereof that can improve the efficiency of pin position identification while ensuring the packaging reliability of the acoustic wave device, as well as a module equipped with the acoustic wave device. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides an acoustic wave device comprising: a device chip; a plurality of external connection terminals; a roof layer; and a support layer; the support layer is formed between a main surface of the device chip and one surface of the roof layer and supports the roof layer; the external connection terminal is formed in a through hole penetrating the support layer and the roof layer and connected to a main surface of the device chip; A multi-point identification pattern is formed on a surface of the roof layer opposite to the one surface thereof, for identifying one of the plurality of external connection terminals as an identification target connection terminal and for distinguishing it from the other external connection terminals; The multi-point identification pattern comprises at least two dot patterns, and the dot patterns are formed as blind holes formed on the opposite surface of the roof layer.

[0010] One aspect of the present invention is to make the shortest distance between the connection terminal to be identified and the multi-point identification pattern shorter than the shortest distance between the external connection terminals other than the connection terminal to be identified and the multi-point identification pattern.

[0011] The device chip includes an IDT electrode and a pad electrode, the IDT electrode is formed on the main surface of the device chip made of a piezoelectric material, In one aspect of the present invention, the pad electrode is formed on the main surface and connected to the external connection terminal.

[0012] In one embodiment of the present invention, the roof layer and the support layer are made of a photosensitive resin.

[0013] In one aspect of the present invention, the depth of the dotted pattern is set to 1 μm or more and 5 μm or less.

[0014] In one aspect of the present invention, the dotted pattern is circular, and the diameter of the circle is less than one-fifth the diameter of the through-hole.

[0015] In order to achieve the above object, the present invention provides a method for manufacturing an acoustic wave device, the method being applied to the acoustic wave device, and comprising the steps of: forming the IDT electrodes and the pad electrodes on the device chip; forming the support layer outside a region where the IDT electrodes are formed in the device chip, and providing the support layer with a first overlap region with respect to the pad electrodes; forming the roof layer on the support layer, the support layer having a second overlap region with one side of the roof layer; forming a through hole penetrating the roof layer and the support layer in the second overlapping region, and exposing the pad electrode in the first overlapping region at a bottom of the through hole; forming the multi-point identification pattern capable of identifying any one of the plurality of external connection terminals on a surface opposite to the one surface of the roof layer; a step of filling the through-holes with a conductive material to form external connection terminals; It is intended to be equipped with the following:

[0016] In the method for manufacturing an acoustic wave device, the step of forming the multi-point identification pattern on the surface opposite to the one surface of the roof layer is a step of exposing and developing the surface opposite to the one surface of the roof layer using a mask to form the multi-point identification pattern; the roof layer after the development includes a dissolved portion, a non-dissolved portion, and a partially dissolved portion, the dissolved portion is a region where the roof layer is dissolved during development to form the through-hole, the non-dissolvable portion is a region in which the roof layer does not dissolve during development, In one aspect of the present invention, the partially dissolved portion is a region where the roof layer is partially dissolved during development and the blind hole is formed.

[0017] In one aspect of the present invention, the mask has fine light-shielding or light-transmitting portions for forming the partially dissolved portion on the roof layer.

[0018] In order to achieve the above object, the present invention provides a module including the acoustic wave device. [Effects of the Invention]

[0019] The acoustic wave device of the present invention solves the problem that it is difficult to improve the pin position identification efficiency of an acoustic wave device while ensuring package reliability in conventional packaging processes, and can improve both the pin position identification efficiency and package reliability. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a top view of an acoustic wave device according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the acoustic wave device shown in FIG. 1 taken along the AA direction. [Figure 3] FIG. 3 is an enlarged view of the circled portion in FIG. [Figure 4] FIG. 4 is a top view of an acoustic wave device according to another embodiment of the present invention. [Figure 5] FIG. 5 is a structural diagram showing the process of forming a multi-point identification pattern on the roof layer. [Figure 6] FIG. 6 is a structural diagram showing the process of forming a multi-point identification pattern on the roof layer. [Figure 7] FIG. 7 is a cross-sectional view of a module including an acoustic wave device. DETAILED DESCRIPTION OF THE INVENTION

[0021] In order to make the objectives, technical means and advantages of the present invention more clearly understandable, the present invention will be described below with reference to the accompanying drawings and examples.

[0022] An acoustic wave device according to an embodiment of the present invention will now be described. First, an acoustic wave device will be described with reference to the accompanying drawings: Fig. 1 is a plan view of an acoustic wave device according to this embodiment, and Fig. 2 is a cross-sectional view of the acoustic wave device shown in Fig. 1 taken along the AA direction. As shown in FIG. 2, the acoustic wave device includes a device chip 100, an external connection terminal 200, a roof layer 300, and a support layer 400. The support layer 400 is formed between the main surface 100 a of the device chip 100 and one surface 300 a of the roof layer 300 , and supports the roof layer 300 . The external connection terminals 200 are provided in through holes formed in the support layer 400 and the roof layer 300 , and are connected to the main surface 100 a of the device chip 100 . A multi-point identification pattern P is formed on the opposite surface 300b of the roof layer 300 from one surface 300a, and this identification pattern P makes it possible to recognize any one of the plurality of external connection terminals 200 as an identification target connection terminal and distinguish it from the other external connection terminals 200. The multi-point identification pattern P has at least two dot-like patterns P1.

[0023] Specifically, the device chip 100 is a rectangular plate-like body with a side length of 0.5 mm to 1 mm and a thickness of 0.15 mm to 0.2 mm, and is used to propagate acoustic waves. The materials constituting the external connection terminals 200 include, but are not limited to, tin, lead, copper, gold, tin-silver alloys, or other solder alloys, which have good electrical connectivity, an appropriate melting point, and excellent adhesion to the device chip and wiring substrate (not shown in FIG. 2). Furthermore, these materials can meet specific mechanical and thermal stress requirements, ensuring the reliability and long-term stability of the package.

[0024] One end of the external connection terminal 200 is connected to the main surface 100a of the device chip 100, and the other end is connected to wiring on a wiring substrate (not shown), and is connected to an external circuit or grounded via the wiring substrate. The external circuit may include a signal transmitting circuit or a signal receiving circuit. The roof layer 300, the support layer 400, and the device chip 100 form a sealed space, i.e., a cavity 500. Additionally, the support layer has a thickness of 10 μm to 20 μm in a direction perpendicular to the main surface 100a of the device chip 100, and the roof layer has a thickness of 15 μm to 45 μm in a direction perpendicular to the main surface 100a of the device chip 100.

[0025] As shown in FIG. 2, a multi-point identification pattern P is formed on the opposite surface 300b of the roof layer 300 from the one surface 300a. The multi-point identification pattern P includes at least two dot-like patterns P1. When the dot-like pattern P1 is circular, its diameter is less than 10 μm. The multi-point identification pattern P enables one of the external connection terminals 200 provided on the opposite surface 300b of the one surface of the roof layer 300 to be identified as a connection terminal to be distinguished from the other external connection terminals 200. Specifically, in this embodiment, the external connection terminal 200 located in the upper left corner of the opposite surface 300b of the one surface of the roof layer 300 in FIG. 1 is designated as pin 1. The shortest distance from the dot-like pattern P1 in the multi-point identification pattern P to the external connection terminal 200 designated as pin 1 (i.e., the connection terminal to be identified) is configured to be shorter than the shortest distances to the other three external connection terminals 200. Therefore, the multi-point identification pattern P can function as an identification mark for the pin position in the acoustic wave device.

[0026] In the above-described acoustic wave device, there is no need to separately form a metal film of a predetermined shape on the roof layer 300. By forming a multi-point identification pattern P on the roof layer 300, the external connection terminal 200 that is the first pin can be identified, thereby improving the efficiency of identifying pin positions in the acoustic wave device.

[0027] In some embodiments, the device chip 100 includes an IDT electrode 101 and a pad electrode 102 . The IDT electrodes are formed on the main surface 100 a of the device chip 100 , and the pad electrodes 102 are formed on the main surface 100 a of the device chip 100 and are connected to the external connection terminals 200 . Specifically, the device chip 100 is a rectangular plate-like body. At least one surface of the device chip 100 is made of a piezoelectric material, and this surface becomes the main surface 100a of the device chip 100. The piezoelectric material includes a piezoelectric material such as lithium tantalate or lithium niobate. The IDT electrode 101 is formed on the main surface 100a of the device chip 100 and is composed of multiple electrode pairs. Each electrode pair has multiple electrode fingers, which are connected at one end by a bus bar. The multiple electrode fingers are arranged parallel to each other so that their longitudinal direction intersects the propagation direction of the elastic wave. The pad electrode 102 is composed of a conductive layer of aluminum, copper, nickel, gold, platinum, or the like. In another embodiment, the device chip 100 may be configured by laminating a piezoelectric material and a support material such as sapphire, silicon, aluminum oxide, spinel, quartz, or glass. The coefficient of thermal expansion (CTE) of this support material is smaller than that of the piezoelectric material. In some embodiments, the material of which the roof layer and the support layer are made is a photosensitive resin.

[0028] Specifically, the material constituting the roof layer 300 and the support layer 400 is a photosensitive resin with thermosetting properties, which prevents warping and deformation of the roof layer 300 and the support layer 400 due to high temperatures during the baking heat treatment process. The above material is also adhesive at room temperature and has the function of removing unnecessary portions by exposure and development in the photolithography process.

[0029] In some embodiments, the dotted pattern P1 is a blind hole P2 formed on the opposite surface 300b of one surface 300a of the roof layer 300 and is located within the contour of the opposite surface 300b. In some embodiments, the depth of the dot pattern P1 is in the range of 1 μm to 5 μm. Specifically, the depth of the dot pattern P1 corresponds to the depth of the blind hole P2. FIG. 3 is a partial enlarged view of FIG. 2 , showing the dot pattern P1 formed on the opposite surface 300b of the roof layer 300. The dot pattern P1 is formed as a blind hole P2 having a depth t3 perpendicular to the surface 300a of the roof layer 300, which is smaller than the thickness of the roof layer 300 (see reference numeral t2 in FIG. 2 ). This t3 is set to a value ranging from 1 μm to 5 μm. In contrast, the depth of the blind hole P2 formed on the opposite surface 300b of the roof layer 300 by conventional laser marking typically exceeds 10 μm. Therefore, the blind hole P2 with a depth t3 formed in the roof layer 300 in this embodiment is difficult to form using conventional laser marking techniques. Furthermore, the blind hole P2 with a depth t3 in this embodiment causes less damage to the roof layer 300 than that formed by laser marking, thereby improving the packaging reliability of acoustic wave devices.

[0030] In some embodiments, the dotted pattern P1 comprises a circular or elliptical shape. In some embodiments, when the dot pattern P1 is circular, its diameter is less than 1 / 5 of the diameter of the through-hole through which the external connection terminal 200 passes. Specifically, the diameter of the through hole refers to the diameter of the circular outline on the opposite surface 300b of the roof layer 300 from the first surface 300a, and the diameter ranges from 30 μm to 80 μm. The diameter of the dot pattern P1 refers to the diameter of the circular outline on the opposite surface 300b of the roof layer 300 from the first surface 300a. For a given number of dot patterns P1 required to form the multi-dot identification pattern P, the smaller the diameter of the dot pattern P1, the smaller the area occupied by the formed multi-dot identification pattern P, and as a result, the less damage to the roof layer 300. Therefore, in this embodiment, the diameter of the dot pattern P1 is controlled to be less than one-fifth the diameter of the through hole, thereby reducing damage to the roof layer 300 caused by the formation of the multi-dot identification pattern P and ensuring the reliability of the acoustic wave device.

[0031] In some embodiments, the multi-point identification pattern P has an area that overlaps with the support layer 400 when viewed from above from the opposite surface 300b of the one surface 300a of the roof layer 300. More specifically, as shown in FIG. 1, in a top view from the opposite surface 300b of one surface 300a of the roof layer 300, the multi-point identification pattern P has an area that overlaps with the support layer 400 and the cavity 500 on which the external connection terminal 200 corresponding to pin 1 is arranged.

[0032] In some embodiments, the multi-point identification pattern P can also be used to identify the product and the company to which the product belongs. Specifically, a multi-point identification pattern P in the form of a string of characters is formed using the dot pattern P1, which can be used to identify the product and the company to which it belongs. Fig. 4 is a top view of the acoustic wave device according to this embodiment. As shown in Fig. 4, the string "123" is formed on the opposite surface 300b of one surface 300a of the roof layer 300. This serves as a product code for the acoustic wave device and is used to identify the acoustic wave device. In this way, the multi-point identification pattern P according to the present invention contributes to diversifying product identification means.

[0033] This preferred embodiment solves the problem that it is difficult to improve pin position identification efficiency while ensuring package reliability in the conventional packaging process for acoustic wave devices. That is, by forming a multi-point identification pattern P on the roof layer 400 and enabling identification of the connection terminal to be identified among the external connection terminals 200 using this multi-point identification pattern P, the identification efficiency of the connection terminal to be identified, which is designated as pin 1 among the external connection terminals 200, is improved. In addition, in the present invention, the depth of the blind hole P2 formed in the roof layer 400 is set to be shallower than that formed by conventional laser marking, which suppresses damage to the roof layer 400 and thereby improves the packaging reliability of the acoustic wave device.

[0034] The present application also provides a method for manufacturing an acoustic wave device that can be applied to manufacturing the acoustic wave device according to the above embodiment. The method includes the following steps. Step S101: The pad electrodes 102 and the IDT electrodes 101 are formed on the device chip 100. Step S102: On the device chip 100, a support layer 400 is formed outside the region where the IDT electrodes 101 are formed, and the support layer 400 is provided with a first overlap region with respect to the pad electrodes 102. Step S103: Form the roof layer 300 on the support layer 400, so that the support layer 400 has a second overlapping region with respect to the one surface 300a of the roof layer 300. Step S104: In the second overlapping region, a through-hole is formed through the roof layer 300 and the support layer 400, and the pad electrode 102 in the first overlapping region is exposed at the bottom of the through-hole. Step S105: A multi-point identification pattern P is formed on the opposite surface 300b of the one surface 300a of the roof layer 300. The multi-point identification pattern P identifies one of the plurality of external connection terminals 200 as an identification target connection terminal, making it possible to distinguish it from the other external connection terminals 200. Step S106: The through-holes are filled with a conductive material to form the external connection terminals 200. By forming the multi-point identification pattern P on the roof layer 300 through the above steps, it becomes possible to identify the pin positions in the acoustic wave device, thereby improving the efficiency of identifying the pin positions. Furthermore, in the present application, the depth of the blind hole P2 formed in the roof layer 300 is set shallower than that formed by conventional laser marking, which reduces damage to the roof layer 300 and improves the packaging reliability of the acoustic wave device. In some embodiments, the step of forming the multi-point identification pattern P on the opposite surface 300b of the one surface 300a of the roof layer 300 comprises the following steps. Step S201: Using a mask, the opposite surface 300b of the roof layer 300 is exposed to light and developed to form a multi-point identification pattern P. Step S202: After development, the roof layer 300 includes a dissolved portion 300d, a non-dissolved portion 300e, and a partially dissolved portion 300f. The dissolved portion 300d is a region where the roof layer 300 dissolves during development to form a through hole, the non-dissolved portion 300e is a region where the roof layer 300 does not dissolve during development, and the partially dissolved portion 300f is a region where the roof layer 300 partially dissolves during development to form a blind hole P2.

[0035] Specifically, Figures 5 and 6 are structural diagrams showing the formation of a multi-point identification pattern on the roof layer 300 in this embodiment. In Figure 5, a negative photosensitive resin material is used as the constituent material of the roof layer 300, while in Figure 6, a positive photosensitive resin material is used as the constituent material of the roof layer 300. As shown in Figures 5 and 6, the multi-point identification pattern is formed by exposing and developing one surface 300b of the roof layer 300 opposite to one surface 300a using a mask M. After development, the roof layer 300 is classified into a dissolved portion 300d, a non-dissolved portion 300e, and a partially dissolved portion 300f depending on the state of dissolution. The dissolved portion 300d is a region where through-holes are formed in the roof layer 300 during development. The non-dissolved portion 300e is a region where the roof layer 300 does not dissolve during development. The partially dissolved portion 300f is a region where the roof layer 300 is partially dissolved during development, forming a blind hole P2 on the opposite surface 300b of the roof layer 300 from the first surface 300a. The depth t3 of the blind hole P2 is the distance between the opposite surface 300b of the roof layer 300 from the first surface 300a and the bottom 300c of the blind hole P2. The depth t3 of the blind hole P2 can be adjusted by adjusting conditions such as the size, width, and exposure wavelength of the image projected onto the opposite surface 300b of the roof layer 300 from the first surface 300a using the mask Ma or mask Mb. In this embodiment, the depth t3 of the blind hole P2 is set to 1 μm to 5 μm, which reduces damage to the roof layer 300 and improves the packaging reliability of the acoustic wave device.

[0036] In some embodiments, the mask M for forming the partially dissolved portions 300f in the roof layer 300 includes fine light-shielding portions or fine light-transmitting portions. Specifically, Fig. 5 shows an example in which a fine light-shielding mask Ma having fine light-shielding portions is formed on a mask M, and by using this fine light-shielding mask Ma and going through exposure and development processes, it is possible to form partially dissolved portions 300f on a roof layer 300 made of a negative photosensitive resin material. Fig. 6 shows an example in which a fine light-transmitting mask Mb having fine light-transmitting portions is formed on a mask M, and by using this fine light-transmitting mask Mb and going through exposure and development processes, it is possible to form partially dissolved portions 300f on a roof layer 300 made of a positive photosensitive resin material.

[0037] When forming the dot-like pattern P1, the fine light-shielding portions or the fine light-transmitting portions are formed in a dot-like pattern, and the size of the projected image formed on the roof layer 300 by the fine light-shielding portions or the fine light-transmitting portions is set to a dimension less than the resolution limit of the photosensitive resin material constituting the roof layer 300. That is, the size of the projected image is set smaller than the minimum dimension (the resolution limit) that allows the dissolving portion 300d to be formed below the projected image, thereby making it possible to form the partially dissolving portion 300f below the projected image.

[0038] When the roof layer 300 is made of a negative photosensitive resin material (FIG. 5), an unexposed-exposed laminated portion can be formed directly below the location where the projected image of the fine light-shielding portion is formed, where the opposite surface 300b of the roof layer 300 is unexposed but one surface 300a of the roof layer 300 is exposed by light that has come around from the side. This unexposed-exposed laminated portion can then function as the partially dissolved portion 300f.

[0039] When the roof layer 300 is made of a positive photosensitive resin material (FIG. 6), an exposed-unexposed laminated portion can be formed directly below the location where the projected image of the fine light-transmitting portion is formed in the roof layer 300. The exposed-unexposed laminated portion is exposed on the opposite surface 300b of the roof layer 300, but is unexposed on one surface 300a of the roof layer 300 due to light diffusion. This exposed-unexposed laminated portion can then function as the partially dissolved portion 300f.

[0040] FIG. 7 is a cross-sectional view of an acoustic wave device module according to this embodiment. As shown in FIG. 7, the module includes an acoustic wave device 600, an inductor 700, a sealing portion 900, a wiring substrate 800, an IC integrated circuit component 801, and a connection terminal 802. The connection terminal 802 is formed on the underside of the wiring substrate 800 and is connected to an external circuit substrate. The IC integrated circuit component 801 is mounted inside the wiring substrate 800 and includes a switching circuit and a low-noise amplifier (LNA). The inductor 700 is mounted on the main surface of the wiring substrate 800 and is used to achieve impedance matching in a signal transmission circuit. Note that in other embodiments, the inductor 700 may be another passive component. The sealing portion 900 is used to seal components such as the acoustic wave device 600 and the inductor 700.

[0041] The expressions and terms used in the present invention are used for the convenience of explanation and are not intended to limit the present invention. As used herein, the terms "including," "comprising," "having," "including," and variations thereof are meant to encompass the listed elements and equivalents thereof, as well as additional elements. As used herein, the term "embodiment" means that a particular configuration, feature, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. The various appearances of this term in this specification do not necessarily mean that they all refer to the same embodiment, nor that the embodiments are mutually exclusive, existing independently or in the alternative. As will be clearly or implicitly understood by those skilled in the art, the embodiments described in this specification can be implemented in any combination with other embodiments to the extent that they are not mutually inconsistent. The above-described embodiments illustrate some exemplary aspects of the present invention, and the descriptions thereof are relatively specific and detailed, but it should be noted that the technical scope of the present invention is not limited thereby. It will be readily apparent to those skilled in the art that various alterations, modifications, and improvements can be made to the structure of the present invention without departing from the spirit or scope of the present invention. Therefore, the technical scope of the present invention is to be defined by the appended claims, and all changes, modifications, and substitutions that fall within the meaning and range of equivalency of the claims are intended to be embraced within the scope of the present invention. [Explanation of symbols]

[0042] 100 device chips 101 IDT electrode 102 Pad electrode 100a Main surface of device chip 200 External connection terminal 300 roof layer 300a One side of the roof layer 300b Opposite side of one side of the roof layer 300c bottom 400 support layer 500 cavity P Multi-point discrimination pattern P1 Dotted Pattern P2 Blind Hole M Mask Ma Fine light-shielding mask Mb fine light-transmitting mask 600 Acoustic Wave Devices 700 inductor 800 wiring board 900 Sealing part 801 IC integrated circuit parts 802 connection terminal

Claims

1. a device chip, a plurality of external connection terminals, a roof layer, and a support layer; the support layer is formed between a main surface of the device chip and one surface of the roof layer and supports the roof layer; the external connection terminal is formed in a through hole penetrating the support layer and the roof layer and connected to a main surface of the device chip; A multi-point identification pattern is formed on a surface of the roof layer opposite to the one surface thereof, for identifying one of the plurality of external connection terminals as an identification target connection terminal and for distinguishing it from the other external connection terminals; An acoustic wave device, wherein the multi-point identification pattern comprises at least two dot-like patterns, and the dot-like patterns are formed as blind holes on the opposite surface of the roof layer.

2. 2. The acoustic wave device according to claim 1, wherein the shortest distance between the connection terminal to be identified and the multi-point identification pattern is shorter than the shortest distance between the external connection terminals other than the connection terminal to be identified and the multi-point identification pattern.

3. the device chip includes an IDT electrode and a pad electrode; the IDT electrode is formed on the main surface of the device chip made of a piezoelectric material, The acoustic wave device according to claim 1 , wherein the pad electrode is formed on the main surface and connected to the external connection terminal.

4. The acoustic wave device according to claim 1 , wherein the roof layer and the support layer are made of a photosensitive resin.

5. The acoustic wave device according to claim 1 , wherein the depth of the dotted pattern is 1 μm or more and 5 μm or less.

6. The acoustic wave device according to claim 1 , wherein the dotted pattern is circular, and the diameter of the circle is less than one-fifth the diameter of the through-hole.

7. A manufacturing method applicable to the acoustic wave device according to any one of claims 1 to 6, comprising: forming the IDT electrodes and the pad electrodes on the device chip; forming the support layer outside a region where the IDT electrodes are formed in the device chip, and providing the support layer with a first overlap region with respect to the pad electrodes; forming the roof layer on the support layer, the support layer having a second overlap region with one side of the roof layer; forming a through hole penetrating the roof layer and the support layer in the second overlapping region, and exposing the pad electrode in the first overlapping region at a bottom of the through hole; forming the multi-point identification pattern capable of identifying any one of the plurality of external connection terminals on a surface opposite to the one surface of the roof layer; a step of filling the through-holes with a conductive material to form external connection terminals; A method for manufacturing an acoustic wave device, comprising:

8. 8. The method for manufacturing an acoustic wave device according to claim 7, the step of forming the multi-point identification pattern on the surface opposite to the one surface of the roof layer is a step of exposing and developing the surface opposite to the one surface of the roof layer using a mask to form the multi-point identification pattern; the roof layer after the development includes a dissolved portion, a non-dissolved portion, and a partially dissolved portion, the dissolved portion is a region where the roof layer is dissolved during development to form the through-hole, the non-dissolvable portion is a region in which the roof layer does not dissolve during development, The partially dissolved portion is a region where the roof layer is partially dissolved during development to form the blind hole.

9. The method for manufacturing an acoustic wave device according to claim 8 , wherein the mask includes fine light-shielding portions or fine light-transmitting portions for forming the partially dissolved portions on the roof layer.

10. A module comprising the acoustic wave device according to claim 1 .

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