Acoustic layer preparation method, ultrasonic chip and ultrasonic fingerprint module

Abstract

The embodiment of the present application provides a method for preparing an acoustic layer, an ultrasonic chip, and an ultrasonic fingerprint module. The acoustic layer is used to generate an ultrasonic signal for the ultrasonic chip, and the method for preparing the acoustic layer includes: using an acoustic layer raw material and a silk screen plate with at least one silk screen opening, silk screen printing on a wafer, so that the acoustic layer raw material passes through at least one silk screen opening, and at least one acoustic material layer is formed on the wafer, wherein the area of ​​the acoustic material layer is larger than the area of ​​the acoustic layer of a predetermined shape and size; and dividing at least one acoustic material layer to prepare at least one acoustic layer of a predetermined shape and size on the wafer.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of manufacturing process technology, and in particular to a method for preparing an acoustic layer, an ultrasonic chip, and an ultrasonic fingerprint module. Background Art

[0002] Ultrasonic chips have been widely used in today's ultrasonic fingerprint modules. Ultrasonic fingerprint modules are often used for fingerprint recognition of electronic devices. The sound path used to transmit ultrasonic signals on electronic devices equipped with ultrasonic fingerprint modules generally includes multiple laminated materials, among which the various laminated materials of the ultrasonic chip have high requirements for material quality. For example, the surface quality, thickness uniformity, presence or absence of foreign matter, and defects of the material may affect the performance of the ultrasonic chip, thereby affecting the quality of the fingerprint image obtained by the ultrasonic fingerprint module and reducing the fingerprint recognition performance. In particular, the materials on the front and back sides of the acoustic layer of the ultrasonic chip used to generate ultrasonic signals are all located on the sound path, and the requirements for thickness uniformity are higher.

[0003] Therefore, how to make the thickness uniformity of the acoustic layer of the ultrasonic chip has become a technical problem that needs to be solved. Summary of the invention

[0004] The embodiments of the present application provide a method for preparing an acoustic layer, an ultrasonic chip, and an ultrasonic fingerprint module to at least partially improve the above-mentioned problems.

[0005] According to a first aspect of an embodiment of the present application, a method for preparing an acoustic layer is provided, wherein the acoustic layer is used to generate an ultrasonic signal for an ultrasonic chip, and the method comprises:

[0006] Using an acoustic layer raw material and a screen printing plate with at least one screen opening, screen printing is performed on a wafer so that the acoustic layer raw material passes through the at least one screen opening to form at least one acoustic material layer on the wafer, wherein the area of ​​the acoustic material layer is larger than the area of ​​the acoustic layer of a predetermined shape and size;

[0007] At least one acoustic material layer is divided into two layers to prepare at least one acoustic layer with a predetermined shape and size on the wafer.

[0008] In some optional embodiments, the acoustic layer is rectangular in shape, and the length of the acoustic layer along the first direction is a first predetermined length A, the length of the acoustic layer along the second direction is a second predetermined length B, and the first direction is perpendicular to the second direction; wherein, the first length C of the maximum inscribed rectangle along the first direction of at least one of the acoustic material layers satisfies the following relationship with the first predetermined length A: C=A, and the second length D of the maximum inscribed rectangle along the second direction of the acoustic material layer satisfies the following relationship with the second predetermined length B: D>B.

[0009] In some optional embodiments, the acoustic layer is rectangular in shape, and the length of the acoustic layer along the first direction is a first predetermined length A, the length of the acoustic layer along the second direction is a second predetermined length B, and the first direction is perpendicular to the second direction; wherein, the first length C of the maximum inscribed rectangle along the first direction of at least one of the acoustic material layers satisfies the following relationship with the first predetermined length A: C>A, and the second length D of the maximum inscribed rectangle along the second direction of the acoustic material layer satisfies the following relationship with the second predetermined length B: D>B.

[0010] In some optional embodiments, the acoustic layer is rectangular in shape, and the length of the acoustic layer along the first direction is a first predetermined length A, the length of the acoustic layer along the second direction is a second predetermined length B, and the first direction is perpendicular to the second direction; wherein, the first length C of the maximum inscribed rectangle along the first direction of at least one of the acoustic material layers satisfies the following relationship with the first predetermined length A: C>2A, and the second length D of the maximum inscribed rectangle along the second direction of the acoustic material layer satisfies the following relationship with the second predetermined length B: D>B.

[0011] In some optional embodiments, after at least one of the acoustic material layers is segmented, a plurality of acoustic layers of predetermined shapes and sizes are prepared.

[0012] In some optional embodiments, forming at least one acoustic material layer on the wafer includes: forming a plurality of acoustic material layers arranged in parallel on the wafer.

[0013] In some optional embodiments, a pad area of ​​at least one ultrasonic chip is formed on the wafer, and after at least one acoustic material layer is formed on the wafer, at least one of the pad areas is not in contact with the acoustic material layer.

[0014] In some optional embodiments, a plurality of pad areas of ultrasonic chips are formed on the wafer, and the pad areas of the plurality of ultrasonic chips are arranged into multiple rows along a first direction; forming at least one acoustic material layer on the wafer comprises: forming a plurality of acoustic material layers arranged at intervals along the first direction on the wafer; and after forming the plurality of acoustic material layers arranged at intervals along the first direction on the wafer, at least one row of the pad areas is located in the spacing area between two adjacent acoustic material layers.

[0015] In some optional embodiments, after a plurality of acoustic material layers arranged at intervals along the first direction are formed on the wafer, two rows of pad areas exist in the interval area between at least one group of two adjacent acoustic material layers.

[0016] According to a second aspect of an embodiment of the present application, an ultrasonic chip is provided, comprising: an acoustic layer for generating an ultrasonic signal, the acoustic layer being of a predetermined shape and size, wherein the acoustic layer is prepared by the method described in the first aspect above.

[0017] According to a third aspect of the embodiments of the present application, an ultrasonic fingerprint module is provided, including: the ultrasonic chip provided by the second aspect above.

[0018] The preparation scheme of the acoustic layer in the embodiment of the present application can utilize the acoustic layer raw material and the silk screen plate with at least one silk screen opening to perform silk screen printing on the wafer, so that the acoustic layer raw material passes through the at least one silk screen opening to form at least one acoustic material layer on the wafer, wherein the area of ​​the acoustic material layer is larger than the area of ​​the acoustic layer of the predetermined shape and size, and then the at least one acoustic material layer is segmented to prepare at least one acoustic layer of the predetermined shape and size on the wafer, and the thickness uniformity of the prepared at least one acoustic layer of the predetermined shape and size is good, and then the performance of the ultrasonic chip produced using the acoustic layer prepared in this scheme is good. When the ultrasonic chip is used in the ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is good, and the fingerprint recognition performance is also good. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0020] Figure 1 A flow chart showing an exemplary method for preparing an acoustic layer in the present application.

[0021] Figure 2A schematic diagram showing a process for preparing an acoustic layer according to an example of the present application.

[0022] Figure 3 A schematic diagram showing a preparation process of an acoustic layer according to another example of the present application.

[0023] Figure 4 A schematic diagram showing a preparation process of an acoustic layer according to yet another example of the present application.

[0024] Figure 5 A schematic diagram showing a preparation process of an acoustic layer according to another example of the present application is shown.

[0025] Figure 6 A schematic diagram of a process of preparing an acoustic layer on a wafer by screen printing in the related art is shown.

[0026] Figure 7 A schematic diagram of an ultrasonic chip according to an example of the present application is shown.

[0027] Figure 8 A schematic diagram of an example ultrasonic fingerprint module in the present application is shown. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0029] The specific implementation of the technical solution of the embodiment of the present application is described below in conjunction with the accompanying drawings. It should be noted that for the convenience of illustration in each of the drawings, each structure may not be drawn according to the actual scale. Each of the drawings does not serve as any limitation to the embodiment of the present application.

[0030] Figure 1 A flowchart of a method for preparing an acoustic layer according to an example of the present application is shown. Figure 1 As shown, the method for preparing the acoustic layer includes step S102 and step S104, specifically:

[0031] Step S102: screen printing is performed on a wafer using an acoustic layer raw material and a screen printing plate with at least one screen opening, so that the acoustic layer raw material passes through the at least one screen opening to form at least one acoustic material layer on the wafer, wherein the area of ​​the acoustic material layer is larger than the area of ​​the acoustic layer of the predetermined shape and size;

[0032] Step S104: dividing at least one acoustic material layer to prepare at least one acoustic layer of a predetermined shape and size on the wafer.

[0033] Based on this, through the preparation scheme of the acoustic layer in the embodiment of the present application, the thickness uniformity of at least one acoustic layer of a predetermined shape and size prepared is good, and then the performance of the ultrasonic chip produced using the acoustic layer prepared in this scheme is good. When the ultrasonic chip is used in the ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is good and the fingerprint recognition performance is also good.

[0034] The preparation method of the acoustic layer in the present application is described in detail below.

[0035] In the present application, the acoustic layer 100 is used to generate ultrasonic signals for the ultrasonic chip. Specifically, the acoustic layer 100 can generate ultrasonic signals under certain conditions and transmit the ultrasonic signals to the outside. The certain condition can be, for example, when the acoustic layer receives a suitable voltage.

[0036] Optionally, the acoustic layer 100 may include a piezoelectric material. By providing a voltage to the piezoelectric material of the acoustic layer, based on the piezoelectric effect of the piezoelectric material, the acoustic layer 100 can generate and emit ultrasonic signals, and receive ultrasonic signals reflected by the external structure, thereby realizing the function of the acoustic layer 100. Optionally, the acoustic layer 100 may be a membrane layer, but the thickness of the acoustic layer 100 is not specifically limited in the present application, and a suitable thickness can be prepared as needed.

[0037] The present application does not limit the piezoelectric material of the acoustic layer 100. For example, the piezoelectric material may include at least one of a single crystal ceramic material, a polycrystalline ceramic material, a polymer material, a thin film material, and a composite material of a polycrystalline material and a polymer material. In some examples, the piezoelectric material of the acoustic layer 100 may include a PVDF (Polyvinylidene fluoride) material, wherein the PVDF material includes but is not limited to PVDF and its copolymers. The acoustic layer 100 using the PVDF material can better meet the function of the acoustic layer 100.

[0038] In the present application, the acoustic layer raw material is the raw material for preparing the acoustic layer 100. As mentioned above, the acoustic layer 100 may include a piezoelectric material, and the acoustic layer raw material may include a piezoelectric material. Since the screen printing method is used in step S102 of the embodiment of the present application, the acoustic layer raw material may be in the form of slurry, coating, etc.

[0039] In the present application, the predetermined shape and size may be the shape and size that the acoustic layer 100 to be prepared needs to meet, and the predetermined shape and size may be reasonably determined according to the requirements of different ultrasonic chips, and no specific limitation is made here. Optionally, each acoustic material layer 30 may be used to prepare at least one acoustic layer 100 of a predetermined shape and size.

[0040] In some optional embodiments, after the at least one acoustic material layer 30 is divided, a plurality of acoustic layers 100 of predetermined shapes and sizes are prepared. Based on this, the present application can more conveniently meet the need of preparing a plurality of acoustic layers 100 on the wafer 10 by dividing such at least one acoustic material layer 30 to prepare a plurality of acoustic layers 100 of predetermined shapes and sizes.

[0041] In the present application, the screen printing plate 20 may include a screen, and the screen opening 21 is an opening on the screen. The screen includes many fine holes. Based on this characteristic of the screen, the screen opening 21 is not actually a complete opening, but is composed of many fine holes. When screen printing is performed in step S102, the acoustic layer material can pass through the multiple fine holes of the screen opening to form an acoustic material layer 30 on the wafer 10. The fine holes in other areas of the screen of the screen printing plate 20 except the screen opening 21 are closed, for example, the closing can be achieved by curing the ink, so the acoustic layer material cannot pass through other areas of the screen of the screen printing plate 20 except the screen opening 21.

[0042] It should be understood that the specific process of screen printing belongs to mature prior art and is not specifically limited in this application. As an example, the working process of screen printing on a wafer using an acoustic layer raw material and a screen printing screen with at least one screen opening in step S102 can be understood according to the following content: the staff first places the screen printing screen 20 above the wafer 10, aligns the screen opening 21 with the appropriate area on the wafer 10, takes an appropriate amount of acoustic layer raw material and places it on the screen of the screen printing screen 20, and then uses a scraper or other tool to scrape the acoustic layer raw material on the screen of the screen printing screen 20. When scraping, the acoustic layer raw material passes through at least one screen opening 21 on the wafer 10 to form an acoustic material layer 30 having an area greater than the area of ​​the acoustic layer 100 of a predetermined shape and size. It should be understood that this exemplary working process of screen printing does not serve as any limitation to this application.

[0043] In the present application, the screen opening 21 on the screen printing plate 20 in step S102 can be any suitable shape, which is not specifically limited here. As a preferred example, the shape of at least one screen opening 12 can be a rectangular shape. The rectangular shape can be a long rectangular shape or a smaller rectangular shape. As another optional example, the shape of at least one screen opening 12 can be an irregular shape, for example, the screen opening 21 can also be an irregular shape such as an "E" shape or an "I" shape. It should be understood that the shapes of these screen openings 21 are not intended to limit the embodiments of the present application.

[0044] Optionally, at least one acoustic material layer 30 obtained in step S102 may be in a strip shape. For example, the acoustic material layer 30 in a strip shape may be formed by a wire mesh opening 21 in a strip shape (e.g., a strip rectangular shape), or may be formed by a wire mesh opening 21 in other irregular shapes (e.g., an "E" shape, an "I" shape, etc.), which is not specifically limited in the present application.

[0045] In the present application, in step S102, when screen printing is performed using the acoustic layer raw material and the screen printing screen 20 having at least one screen opening 21, an acoustic material layer 30 (for example, referring to Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown in the figure, several examples of forming an acoustic material layer 30 on the wafer 10 through a screen opening 21 in the screen printing screen 20 are shown); or, multiple acoustic material layers 30 can be formed through a screen opening 21 (for example, one of the screen openings 21 is "E"-shaped, then during screen printing, three acoustic material layers 30 can be printed on the wafer 10 through only three lateral areas of the "E"-shaped screen opening 21; for example, in other possible examples, one of the screen openings The opening 21 may also be in other shapes such as an "I" shape, and may also form multiple acoustic material layers 30. It should be understood that these examples are not limitations of the present application.); or, M acoustic material layers 30 are formed by N screen openings 21, 2≤N≤M, and N and M are both positive integers (for example, a screen printing plate 20 may have both long strip screen openings 21 and screen openings 21 in shapes such as an "E" shape or an "I" shape. It should be understood that these examples are not limitations of the present application.).

[0046] In some optional embodiments, “forming at least one acoustic material layer on the wafer” in step S102 may include: forming a plurality of acoustic material layers 30 arranged in parallel on the wafer 10 .

[0047] Based on this, in the present application, by forming a plurality of acoustic material layers 30 arranged in parallel on the wafer 10 , it is possible to more conveniently meet the need to prepare a plurality of acoustic layers 100 on the wafer 10 .

[0048] It should be understood that the shapes of the multiple acoustic material layers 30 can be the same or different from each other. The multiple acoustic material layers 30 arranged in parallel on the wafer 10 can be formed by screen printing through one or more screen openings 21 on the screen printing screen 20. For example, referring to Figure 2 , Figure 3 , Figure 4 and Figure 5 In the example shown, the screen printing plate 20 may include a plurality of parallel arranged screen openings 21, and the acoustic layer raw material may be screen printed through the plurality of parallel arranged screen openings 21 to obtain a plurality of parallel arranged acoustic material layers 30; for another example, the screen printing plate 20 may include a screen opening 21, and the screen opening 21 is "E" shaped, and a plurality of parallel arranged acoustic material layers 30 may be formed through three lateral regions of the "E" shaped screen opening 21. It should be understood that these examples are only some optional implementations and are not intended to be any limitation to the present application.

[0049] In the present application, in step S104, by dividing at least one acoustic material layer 30, a larger acoustic material layer 30 on the wafer 10 can be prepared into at least one acoustic layer 100 of a predetermined shape and size. The present application does not limit the specific manner of the dividing process. For example, in an optional embodiment, at least one acoustic material layer 30 can be divided on the wafer 10 by a grinding and cutting process.

[0050] In order to facilitate the understanding of the embodiments of the present application, Figure 6 A method of preparing an acoustic layer on a wafer by screen printing in the related art is described (it should be understood that the related art mentioned here does not necessarily refer to the prior art): Figure 6As shown, a plurality of screen openings 21' of predetermined shapes and sizes are provided on the screen printing screen 20', and then the acoustic layer raw material is screen-printed on the wafer 10' through the plurality of screen openings 21' of predetermined shapes and sizes, so that the acoustic layer raw material passes through the plurality of screen openings 21' of predetermined shapes and sizes to directly form a plurality of acoustic layers 100' of predetermined shapes and sizes on the wafer 10'. During screen printing, the staff needs to use a scraper or other tool to scrape the acoustic layer material on the screen of the screen printing screen 20'. When scraping, the acoustic layer material passes through a plurality of screen openings 21' of predetermined shapes and sizes to directly form a plurality of acoustic layers 100' of predetermined shapes and sizes on the wafer 10'. Due to the large difference in force applied to different areas of the screen during scraping, the thickness of the acoustic layer 100' formed through the screen openings 21' is significantly larger at the edges than the thickness of the middle area of ​​the acoustic layer 100' due to the force difference, resulting in less than ideal thickness uniformity of the acoustic layer 100'.

[0051] Therefore, through the preparation scheme of the acoustic layer in the embodiment of the present application, since the acoustic layer raw material and the silk screen plate 20 with at least one silk screen opening 21 can be used to perform silk screen printing on the wafer 10, so that the acoustic layer raw material passes through the at least one silk screen opening 21, at least one acoustic material layer 30 with an area larger than the area of ​​the acoustic layer 100 of a predetermined shape and size is formed on the wafer 10, and then the at least one acoustic material layer 30 is segmented to prepare at least one acoustic layer 100 of a predetermined shape and size on the wafer 10, so that the thickness of at least part of the edge of the at least one acoustic layer 100 of a predetermined shape and size prepared by the preparation scheme of the present application is reduced compared to the thickness difference in the middle area of ​​the acoustic layer 100, so that the thickness uniformity of the at least one acoustic layer 100 is better, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in this scheme is better. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better, and the fingerprint recognition performance is also better.

[0052] In some optional embodiments, the acoustic layer 100 of predetermined shape and size satisfies: the acoustic layer 100 is rectangular, and the length of the acoustic layer 100 along the first direction F1 is a first predetermined length A, the length of the acoustic layer 100 along the second direction F2 is a second predetermined length B, and the first direction F1 is perpendicular to the second direction F2. One of the first predetermined length A and the second predetermined length B may be the length value of the rectangular shape, and the other may be the width value of the rectangular shape.

[0053] In the present application, in some optional embodiments, the acoustic layer 100 is in a rectangular shape, and the length of the acoustic layer 100 along the first direction F1 is a first predetermined length A, the length of the acoustic layer 100 along the second direction F2 is a second predetermined length B, and the first direction F1 is perpendicular to the second direction F2; wherein, the maximum inscribed rectangle of at least one acoustic material layer 30 obtained by screen printing along the first direction F1 satisfies the first predetermined length C and the first predetermined length A: C=A, and the maximum inscribed rectangle of the acoustic material layer 30 along the second direction F2 satisfies the second predetermined length D and the second predetermined length B: D>B.

[0054] Based on this, some optional embodiments of the present application prepare at least one acoustic layer 100 of a predetermined shape and size on the wafer 10 by dividing the acoustic material layer 30 that satisfies such conditions (C=A and D>B), so that the thickness of the acoustic layer 100 prepared by these optional embodiments at at least one edge along the second direction F2 can be reduced compared to the thickness difference in the middle area of ​​the acoustic layer 100. Therefore, the thickness uniformity of at least one acoustic layer 100 prepared by this optional implementation scheme is better, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in this scheme is better. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better, and the fingerprint recognition performance is also better.

[0055] For example, Figure 2 A schematic diagram showing a process for preparing an acoustic layer in an example of the present application is shown, referring to Figure 2 , wherein an example of the maximum inscribed rectangle of one acoustic material layer 30 is shown, and others can be deduced by analogy, which also shows an example where at least one acoustic material layer 30 satisfies C=A and D>B. It should be understood that Figure 2 The examples shown are not intended to be limiting in this application.

[0056] Optionally, at least one acoustic material layer 30 satisfies C=A and D>2B, so that the acoustic material layer 30 can be used to prepare multiple acoustic layers 100 of predetermined shapes and sizes (multiple acoustic layers 100 can be arranged at intervals along the second direction F2), thereby more conveniently adapting to the need to prepare multiple acoustic layers 100 on the wafer 10.

[0057] In the present application, in some optional embodiments, the acoustic layer 100 is in a rectangular shape, and the length of the acoustic layer 100 along the first direction F1 is a first predetermined length A, and the length of the acoustic layer 100 along the second direction F2 is a second predetermined length B; wherein, the maximum inscribed rectangle of at least one acoustic material layer 30 obtained by screen printing along the first direction F1 satisfies the first predetermined length C and the first predetermined length A: C>A, and the maximum inscribed rectangle of the acoustic material layer 30 along the second direction F2 satisfies the second predetermined length D and the second predetermined length B: D>B.

[0058] Based on this, some optional embodiments of the present application prepare at least one acoustic layer 100 of a predetermined shape and size on the wafer 10 by dividing the acoustic material layer 30 that satisfies such conditions (C=A and D>B), so that the thickness of the acoustic layer 100 prepared by these optional embodiments at at least one edge along the second direction F2 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100, and the thickness of the acoustic layer 100 prepared by these optional embodiments at at least one edge along the first direction F1 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100. Therefore, the thickness uniformity of at least one acoustic layer 100 prepared by this optional implementation scheme is better, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in this scheme is better. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better, and the fingerprint recognition performance is also better.

[0059] For example, Figure 3 , Figure 4 and Figure 5 Schematic diagram showing the preparation process of the acoustic layer of other examples of the present application, refer to Figure 3 , Figure 4 and Figure 5 , all show examples of the maximum inscribed rectangle of one acoustic material layer 30, and the others can be deduced by analogy. It also shows an example where at least one acoustic material layer 30 satisfies C>A and D>B. It should be understood that Figure 3 , Figure 4 and Figure 5 The examples shown are not intended to be limiting in this application.

[0060] Optionally, at least one acoustic material layer 30 satisfies C>A and D>2B, so that the acoustic material layer 30 can be used to prepare multiple acoustic layers 100 of predetermined shapes and sizes (multiple acoustic layers 100 can be arranged at intervals along the second direction F2), thereby more conveniently adapting to the need to prepare multiple acoustic layers 100 on the wafer 10.

[0061] In the present application, in some optional embodiments, the acoustic layer 100 is in a rectangular shape, and the length of the acoustic layer 100 along the first direction F1 is a first predetermined length A, and the length of the acoustic layer 100 along the second direction F2 is a second predetermined length B; wherein, the maximum inscribed rectangle of at least one acoustic material layer 30 obtained by screen printing satisfies the following conditions: C>2A along the first direction F1 and the first predetermined length A, and the maximum inscribed rectangle of the acoustic material layer 30 along the second direction F2 and the second predetermined length B satisfies the following conditions: D>B.

[0062] Based on this, some optional embodiments of the present application prepare at least one acoustic layer 100 of a predetermined shape and size on the wafer 10 by dividing the acoustic material layer 30 that satisfies such conditions (C>2A and D>B), so that the thickness of the acoustic layer 100 prepared by these optional embodiments at at least one edge along the second direction F2 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100, and the thickness of the acoustic layer 100 prepared by these optional embodiments at at least one edge along the first direction F1 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100. Therefore, the thickness uniformity of at least one acoustic layer 100 prepared by this optional implementation scheme is better, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in this scheme is better. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better, and the fingerprint recognition performance is also better.

[0063] For example, Figure 5 Schematic diagram showing the preparation process of the acoustic layer of other examples of the present application, refer to Figure 5 , shows an example of the maximum inscribed rectangle of one acoustic material layer 30, and the others can be deduced by analogy. It also shows an example where at least one acoustic material layer 30 satisfies C>2A and D>B. It should be understood that Figure 5 The examples shown are not intended to be limiting in this application.

[0064] Optionally, at least one acoustic material layer 30 satisfies C>2A and D>2B, so that the acoustic material layer 30 can be used to prepare a plurality of acoustic layers 100 of predetermined shapes and sizes (the plurality of acoustic layers 100 can be arranged at intervals along the second direction F2), thereby more conveniently adapting to the need to prepare a plurality of acoustic layers 100 on the wafer 10.

[0065] In the present application, in order to facilitate the use of the acoustic layer 100 of a predetermined shape and size prepared on the wafer 10 to further package and test the ultrasonic chip, in some optional embodiments, a pad area 11 of at least one ultrasonic chip is formed on the wafer 10 used to prepare the acoustic layer 100 in the present application, and after at least one acoustic material layer 30 is formed on the wafer 10 in step S102, at least one pad area 11 is not in contact with the acoustic material layer 30.

[0066] Specifically, the pad area 11 of the ultrasonic chip can be used for electrical connection. For example, in the prepared ultrasonic chip, the pad area 11 can be used for electrical connection on the ultrasonic fingerprint module, and the pad area 11 can be a gold finger area. Since the pad area 11 that is not in contact with the acoustic material layer 30 can maintain the function of the pad area 11, it can be used for the preparation of the ultrasonic chip without affecting the packaging and testing of the ultrasonic chip. Based on this, the present application can facilitate the use of at least one acoustic material layer 30 to prepare an acoustic layer 100 of a predetermined shape and size, and use at least one pad area 11 that is not in contact with the acoustic material layer 30 to package and test the ultrasonic chip.

[0067] In order to avoid contact between the acoustic material layer 30 and the solder pad area 11 of the wafer 10, the preparation area of ​​the acoustic layer 100 corresponding to each solder pad area 11 on the wafer 10 can be planned in advance. Furthermore, the position of the screen opening 21 on the silk screen printing screen 20 can be designed according to the pre-planned preparation area of ​​the acoustic layer 100, so that in step S102, when screen printing is performed on the wafer 10 using the acoustic layer raw material and the silk screen printing screen 20 with at least one silk screen opening 21, the acoustic layer raw material passes through at least one silk screen opening 21, and at least one acoustic material layer 30 is formed in the preparation area of ​​the acoustic layer 100 planned in advance on the wafer 10 to avoid the solder pad area 11, thereby achieving the purpose of avoiding contact between the acoustic material layer 30 and the solder pad area 11 of the wafer 10.

[0068] In some optional embodiments, a plurality of pad areas 11 of ultrasonic chips are formed on the wafer 10 used to prepare the acoustic layer 100 in the present application, and the pad areas 11 of the plurality of ultrasonic chips are arranged into multiple rows along the first direction F1; the "forming at least one acoustic material layer on the wafer" in step S102 of the present application may include: forming a plurality of acoustic material layers 30 arranged at intervals along the first direction F1 on the wafer 10; and, after forming a plurality of acoustic material layers 30 arranged at intervals along the first direction F1 on the wafer 10, at least one row of pad areas 11 is located in the spacing area between two adjacent acoustic material layers 30.

[0069] Based on this, the present application can facilitate the preparation of an acoustic layer 100 of a predetermined shape and size by using a plurality of acoustic material layers 30 arranged at intervals along a first direction F1, and utilize at least one row of pad areas 11 located in the spacing area between two adjacent acoustic material layers 30 to package and test ultrasonic chips.

[0070] In some optional embodiments, after a plurality of acoustic material layers 30 arranged at intervals along the first direction F1 are formed on the wafer 10 , two rows of pad areas 11 exist in the interval area between at least one group of two adjacent acoustic material layers 30 .

[0071] Based on this, the present application can facilitate the use of at least one group of two adjacent acoustic material layers 30 to prepare an acoustic layer 100 of a predetermined shape and size, and use two rows of pad areas 11 located in the spacing area between the at least one group of two adjacent acoustic material layers 30 to package and test the ultrasonic chip.

[0072] For example, refer to Figure 5 As shown, when the acoustic material layer 30 on the wafer 10 satisfies C>2A and D>B, two rows of ultrasonic chips can be prepared "head to head" through at least one group of two adjacent acoustic material layers 30 and two rows of pad areas 11 located in the spacing area between the at least one group of two adjacent acoustic material layers 30, so as to avoid wasting the pad areas 11, avoid reducing the number of ultrasonic chips that can be prepared on the wafer 10, and improve the utilization rate of the wafer 10.

[0073] Next, combine Figure 6 An example scheme of preparing an acoustic layer on a wafer by screen printing in the related art is introduced. It should be understood that the related art described in this article is not necessarily the prior art. A brief description has been given in the previous text, and the description here is used to facilitate the comparison of the difference between the preparation scheme of the acoustic layer in the related art and the present application, so that the beneficial effects of the technical solution of the embodiment of the present application can be more intuitively seen.

[0074] <Related Technology Solutions>

[0075] Reference Figure 6 As shown, in the solution of the related art, a plurality of pad areas 11' of ultrasonic chips are formed on the wafer 10', and each pad area 11' is used to package an ultrasonic chip; an area for preparing an acoustic layer 100' of a predetermined shape and size is planned above each pad area 11' on the wafer 10' (for convenience of representation, Figure 6 The screen printing plate 20' comprises a plurality of screen openings 21' of predetermined shapes and sizes on the screen, the number of the screen openings 21' is the same as the number of the pad areas 11', and the screen of the screen printing plate 20 is closed except for the screen openings 21'.

[0076] Reference Figure 6 As shown, in the scheme of the related technology, when screen printing is performed using a wafer 10' and a screen printing plate 20', the acoustic layer raw material is screen-printed on the wafer 10' through a plurality of screen openings 21' of predetermined shapes and sizes, so that the acoustic layer raw material passes through the plurality of screen openings 21' of predetermined shapes and sizes to directly form a plurality of acoustic layers 100' of predetermined shapes and sizes on the wafer 10'. During screen printing, the staff needs to use a scraper or other tool to scrape the acoustic layer material on the screen of the screen printing screen 20'. When scraping, the acoustic layer material passes through a plurality of screen openings 21' of predetermined shapes and sizes to directly form a plurality of acoustic layers 100' of predetermined shapes and sizes on the wafer 10'. Due to the large difference in force applied to different areas of the screen during scraping, the thickness of the acoustic layer 100' formed through the screen openings 21' is significantly larger at the edges than the thickness of the middle area of ​​the acoustic layer 100' due to the force difference, resulting in less than ideal thickness uniformity of the acoustic layer 100'.

[0077] Next, combine Figure 2 , Figure 3 , Figure 4 and Figure 5 Some exemplary embodiments of the preparation scheme of the acoustic layer of the present application are described, and these exemplary embodiments can facilitate the understanding of the technical solution of the present application. It should be understood that the following description does not serve as any limitation to the present application.

[0078] <Implementation Plan 1>

[0079] Reference Figure 2 As shown, in Embodiment 1, a plurality of pad areas 11 of ultrasonic chips are formed on the wafer 10 used, and the pad areas 11 of the plurality of ultrasonic chips are arranged in a plurality of rows along a first direction F1, and each row of pad areas 11 includes a plurality of pad areas 11, and each pad area 11 is used to package an ultrasonic chip; an area for preparing an acoustic layer 100 (rectangular shape, and a length along the first direction F1 of a first predetermined length A, and a length along the second direction F2 of a second predetermined length B) of a predetermined shape and size is planned above each pad area 11 on the wafer 10 (for convenience of representation, Figure 2 In the figure, the dotted line is used to indicate the location of the area);

[0080] The silk screen plate 20 used in Implementation Option 1 includes a plurality of silk screen openings 21 located on the silk screen. The plurality of silk screen openings 21 are parallel to each other and arranged at intervals along the first direction F1. The silk screen openings 21 are in the shape of a long rectangular strip. The number of silk screen openings 21 is the same as the number of rows of the pad area 11. The area of ​​the silk screen of the silk screen plate 20 except for the silk screen openings 21 is closed.

[0081] Reference Figure 2 As shown, in Embodiment 1, when the method for preparing the acoustic layer of the present application is implemented using a wafer 10 and a screen printing screen 20, the acoustic layer raw material (for example, including a piezoelectric material) and the screen printing screen 20 can be used to perform screen printing on the wafer 10. The screen opening 21 of each screen printing screen 20 can be aligned with the area for preparing the acoustic layer 100 planned above each row of pad areas 11 on the wafer 10, so that during the screen printing process, the acoustic layer raw material forms an acoustic material layer 30 at the area for preparing the acoustic layer 100 planned on the wafer 10 through a plurality of screen openings 21, and the area of ​​the acoustic material layer 30 is greater than the area of ​​the acoustic layer 100 of a predetermined shape and size, and in Embodiment 1, the first length C of the maximum inscribed rectangle of the acoustic material layer 30 along the first direction F1 = the first predetermined length A, and the second length D of the maximum inscribed rectangle of the acoustic material layer 30 along the second direction F2 > the second predetermined length B (it should be understood that Figure 2 D is greater than multiple times B to meet the need of preparing more acoustic layers 100 along the second direction F1); after forming a plurality of acoustic material layers 30 spaced apart along the first direction F1 on the wafer 10, the plurality of pad regions 11 are located in the spaced region between two adjacent acoustic material layers 30. Afterwards, the plurality of acoustic material layers 30 may be segmented (by using a grinding and cutting process) to prepare a plurality of acoustic layers 100 of predetermined shapes and sizes on the wafer 10 using the acoustic material layers 30.

[0082] The advantages of implementation scheme 1 are: the thickness of the edge of the prepared acoustic layer 100 along the second direction F2 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100, so the thickness uniformity of the acoustic layer 100 prepared in implementation scheme 1 is good, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in implementation scheme 1 is good. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is good, and the fingerprint recognition performance is also good. In addition, the acoustic layer raw material utilization rate is high, and the wafer 10 can be fully utilized to prepare more acoustic layers 100, the pad area 11 on the wafer 10 can be fully utilized (that is, the pad area 11 will not be wasted), and it is convenient to use more acoustic layers 100 and more pad areas 11 to package and test more ultrasonic chips, and the space utilization rate on the wafer 10 is high.

[0083] <Implementation Plan 2>

[0084] The thickness of the acoustic layer 100 prepared in Implementation Option 1 at the edge along the second direction F2 can be reduced compared to the thickness difference in the middle area of ​​the acoustic layer 100. However, since its acoustic material layer 30 satisfies C=A, the thickness of the acoustic layer 100 prepared in Implementation Option 1 at the edge along the first direction F1 is still significantly different from the thickness difference in the middle area of ​​the acoustic layer 100.

[0085] Reference Figure 3 As shown, in Embodiment 2, the same wafer 10 as Embodiment 1 is used (i.e., a plurality of pad areas 11 of ultrasonic chips are formed on the wafer 10, and the pad areas 11 of the plurality of ultrasonic chips are arranged in a plurality of rows along the first direction F1, and each row of pad areas 11 includes a plurality of pad areas 11, and each pad area 11 is used to package an ultrasonic chip; an area for preparing an acoustic layer 100 (rectangular shape, and a length along the first direction F1 of a first predetermined length A, and a length along the second direction F2 of a second predetermined length B) of a predetermined shape and size is planned above each pad area 11 on the wafer 10 (for convenience of representation, Figure 3 In the figure, the dotted line is used to indicate the location of the area);

[0086] The silk screen plate 20 used in Implementation Option 2 includes a plurality of silk screen openings 21 located on the silk screen, the plurality of silk screen openings 21 are parallel to each other and arranged at intervals along the first direction F1, the silk screen openings 21 are in the shape of a long rectangular strip, and the silk screen of the silk screen plate 20 is closed except for the silk screen openings 21; however, it is different from Implementation Option 1 in that the silk screen openings 21 in Implementation Option 2 are larger than the silk screen openings 21 in Implementation Option 1, and the number of silk screen openings 21 is halved.

[0087] Reference Figure 3 As shown, in Embodiment 2, when the method for preparing the acoustic layer of the present application is implemented using a wafer 10 and a screen printing screen 20, the acoustic layer raw material (for example, including a piezoelectric material) and the screen printing screen 20 can be used to perform screen printing on the wafer 10. The screen opening 21 of each screen printing screen 20 can be aligned with the area for preparing the acoustic layer 100 planned above a row of pad areas 11 on the wafer 10, so that during the screen printing process, the acoustic layer raw material forms an acoustic material layer 30 at the area for preparing the acoustic layer 100 planned on the wafer 10 through a plurality of screen openings 21, and the area of ​​the acoustic material layer 30 is greater than the area of ​​the acoustic layer 100 of a predetermined shape and size, and in Embodiment 2, the first length C of the maximum inscribed rectangle of the acoustic material layer 30 along the first direction F1 is greater than the first predetermined length A, and the second length D of the maximum inscribed rectangle of the acoustic material layer 30 along the second direction F2 is greater than the second predetermined length B (it should be understood that Figure 3D is greater than multiple times B to meet the need to prepare more acoustic layers 100 along the second direction F1); after forming multiple acoustic material layers 30 spaced along the first direction F1 on the wafer 10, multiple rows of pad areas 11 are located in the spacing area between two adjacent acoustic material layers 30; in embodiment 2, since the acoustic material layer 30 covers several rows of pad areas 11, the covered pad areas 11 need to be discarded during subsequent use (the reason is that it affects the packaging and testing of the ultrasonic chip). Afterwards, the multiple acoustic material layers 30 can be segmented (by using a grinding and cutting process) to prepare multiple acoustic layers 100 of predetermined shapes and sizes on the wafer 10 using the acoustic material layers 30.

[0088] The advantages of Implementation Option 2 are: the thickness of the prepared acoustic layer 100 at the edge along the second direction F2 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100, and the thickness of the prepared acoustic layer 100 at at least one edge along the first direction F1 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100. Therefore, the thickness uniformity of the acoustic layer 100 prepared in Implementation Option 2 is better, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in Implementation Option 2 is better. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better, and the fingerprint recognition performance is also better.

[0089] <Implementation Plan 3>

[0090] The thickness of the acoustic layer 100 prepared in Implementation Option 2 at the edge along the second direction F2 can be reduced compared to the thickness difference in the middle area of ​​the acoustic layer 100, and the thickness of the acoustic layer 100 prepared at at least one edge along the first direction F1 can be reduced compared to the thickness difference in the middle area of ​​the acoustic layer 100. However, some pad areas 11 on the wafer 10 are wasted in Implementation Option 2.

[0091] Reference Figure 4 As shown, in Embodiment 3, a wafer 10 different from Embodiments 1 and 2 is used, and a plurality of pad areas 11 of ultrasonic chips are formed on the wafer 10 in Embodiment 3, and the pad areas 11 of the plurality of ultrasonic chips are arranged in a plurality of rows along the first direction F1, and each row of pad areas 11 includes a plurality of pad areas 11, and each pad area 11 is used to package an ultrasonic chip; an area for preparing an acoustic layer 100 (rectangular shape, and a length along the first direction F1 of a first predetermined length A, and a length along the second direction F2 of a second predetermined length B) of a predetermined shape and size is planned above each pad area 11 on the wafer 10 (for convenience of representation, Figure 4, the dotted line is used to indicate the position of the region), but it is different from embodiments 1 and 2 in that the number of rows of pad areas 11 in embodiment 3 is reduced by half of the number of rows of pad areas 11 in embodiments 1 and 2, and the spacing between each two adjacent rows of pad areas 11 in embodiment 3 is larger than that in embodiments 1 and 2;

[0092] The silk screen plate 20 adopted in Implementation Option 3 includes a plurality of silk screen openings 21 located on the silk screen, the plurality of silk screen openings 21 are parallel to each other and arranged at intervals along the first direction F1, the silk screen openings 21 are in the shape of a long rectangular strip, the number of silk screen openings 21 is the same as the number of rows of the pad area 11, and the silk screen of the silk screen plate 20 except for the silk screen openings 21 is closed; however, it is different from Implementation Option 1 in that the silk screen openings 21 in Implementation Option 3 are larger than the silk screen openings 21 in Implementation Option 1, and the number of silk screen openings 21 is halved.

[0093] Reference Figure 4 As shown, in Embodiment 3, when the method for preparing the acoustic layer of the present application is implemented using the wafer 10 and the screen printing screen 20, the acoustic layer raw material (for example, including piezoelectric material) and the screen printing screen 20 can be used to perform screen printing on the wafer 10. The screen opening 21 of each screen printing screen 20 can be aligned with the area for preparing the acoustic layer 100 planned above each row of pad areas 11 on the wafer 10, so that during the screen printing process, the acoustic layer raw material forms an acoustic material layer 30 at the area for preparing the acoustic layer 100 planned on the wafer 10 through the plurality of screen openings 21, and the area of ​​the acoustic material layer 30 is greater than the area of ​​the acoustic layer 100 of the predetermined shape and size, and in Embodiment 3, the first length C of the acoustic material layer 30 along the first direction F1> the first predetermined length A, and the second length D of the acoustic material layer 30 along the second direction F2> the second predetermined length B (it should be understood that Figure 4 D is greater than multiple times B to meet the need of preparing more acoustic layers 100 along the second direction F1); after forming a plurality of acoustic material layers 30 spaced apart along the first direction F1 on the wafer 10, at least one row of pad areas 11 is located in the spaced area between two adjacent acoustic material layers 30. Afterwards, the plurality of acoustic material layers 30 can be segmented (by using a grinding and cutting process) to prepare a plurality of acoustic layers 100 of predetermined shapes and sizes on the wafer 10 using the acoustic material layers 30.

[0094] The advantages of implementation scheme 3 are: the thickness of the prepared acoustic layer 100 at the edge along the second direction F2 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100, and the thickness of the prepared acoustic layer 100 at at least one edge along the first direction F1 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100. Therefore, the thickness uniformity of the acoustic layer 100 prepared in implementation scheme 2 is better, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in implementation scheme 2 is better. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better, and the fingerprint recognition performance is also better. In addition, the pad area 11 on the wafer 10 is not wasted, and the pad area 11 on the wafer 10 can be fully utilized, so that the acoustic layer 100 and the pad area 11 can be fully utilized to package and test the ultrasonic chip.

[0095] <Implementation Plan 4>

[0096] The thickness difference of the acoustic layer 100 prepared in Implementation Options 2 and Implementation Options 3 at the edge along the second direction F2 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100, and the thickness difference of the prepared acoustic layer 100 at at least one edge along the first direction F1 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100. However, both of them cannot fully utilize the wafer 10 to prepare more acoustic layers 100, cannot facilitate the use of more acoustic layers 100 and more pad areas 11 to package and test more ultrasonic chips, and the space utilization rate on the wafer 10 is low.

[0097] Reference Figure 5 As shown, in Embodiment 4, the wafer 10 used is different from Embodiments 1, 2 and 3. The wafer 10 used in Embodiment 4 is formed with a plurality of pad areas 11 of ultrasonic chips, and the pad areas 11 of the plurality of ultrasonic chips are arranged into a plurality of rows along the first direction F1, and each row of pad areas 11 includes a plurality of pad areas 11, and each pad area 11 is used to package an ultrasonic chip; every two rows of pad areas 11 on the wafer 10 are regarded as a group, and the interval between each group of pad areas 11 is sufficient to prepare two rows of acoustic layers 100 of predetermined shape and size (rectangular shape, and the length along the first direction F1 is the first predetermined length A, and the length along the second direction F2 is the second predetermined length B), and two adjacent groups of pad areas 11 are arranged close to each other; in each group of pad areas 11, a row of pad areas 11 is arranged below the pad area 11 to plan a row of areas for preparing an acoustic layer 100 of predetermined shape and size (for convenience of representation, Figure 5In the figure, dotted lines are used to indicate the position of the area), and another row of pad areas 11 is planned above the pad areas 11 as an area for preparing an acoustic layer 100 of a predetermined shape and size (it should be understood that through a group of pad areas 11 and the prepared two rows of acoustic layers 100, two rows of ultrasonic chips arranged "head to head" can be packaged).

[0098] The silk screen plate 20 used in Implementation Option 4 includes a plurality of silk screen openings 21 located on the silk screen, the plurality of silk screen openings 21 are parallel to each other and arranged at intervals along the first direction F1, the silk screen openings 21 are in the shape of a long rectangular strip, and the silk screen of the silk screen plate 20 is closed except for the silk screen openings 21; however, it is different from Implementation Option 1 in that the silk screen openings 21 in Implementation Option 4 are larger than the silk screen openings 21 in Implementation Option 1, and the number of silk screen openings 21 is halved.

[0099] Reference Figure 5 As shown, in Embodiment 4, when the method for preparing the acoustic layer of the present application is implemented using the wafer 10 and the silk-screen screen 20 , the acoustic layer raw material (for example, including piezoelectric material) and the silk-screen screen 20 can be used to perform silk-screen printing on the wafer 10 . The screen opening 21 of each screen printing screen 20 can be aligned with the area for preparing two rows of acoustic layers 100 between two rows of pad areas 11 in each group of pad areas 11 on the wafer 10, so that during the screen printing process, the acoustic layer raw material forms an acoustic material layer 30 at the area planned for preparing the acoustic layer 100 on the wafer 10 through multiple screen openings 21, and the area of ​​the acoustic material layer 30 is larger than the area of ​​the acoustic layer 100 of the predetermined shape and size. In Embodiment 4, due to the size of the screen opening, the first length C of the maximum inscribed rectangle of the acoustic material layer 30 along the first direction F1 is greater than 2A (that is, twice the first predetermined length A), and the second length D of the maximum inscribed rectangle of the acoustic material layer 30 along the second direction F2 is greater than the first predetermined length B (it should be understood that Figure 5 D is greater than multiple times B to meet the need of preparing more acoustic layers 100 along the second direction F1); after forming a plurality of acoustic material layers 30 spaced along the first direction F1 on the wafer 10, there are two rows of pad areas 11 in the spacing area between at least one group of two adjacent acoustic material layers 30. Afterwards, the plurality of acoustic material layers 30 can be segmented (by using a grinding and cutting process) to prepare a plurality of acoustic layers 100 of predetermined shapes and sizes on the wafer 10 using the acoustic material layers 30.

[0100] The advantages of implementation scheme 4 are: the thickness of the prepared acoustic layer 100 at the edge along the second direction F2 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100, and the thickness of the prepared acoustic layer 100 at at least one edge along the first direction F1 can be reduced compared with the thickness difference in the middle area of ​​the acoustic layer 100. Therefore, the thickness uniformity of the acoustic layer 100 prepared in implementation scheme 2 is better, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in implementation scheme 2 is better. When the ultrasonic chip is used in the ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better, and the fingerprint recognition performance is also better; moreover, the acoustic layer raw material utilization rate is high, and the wafer 10 can be fully utilized to prepare more acoustic layers 100, the pad area 11 on the wafer 10 can be fully utilized (that is, the pad area 11 will not be wasted), and it is convenient to use more acoustic layers 100 and more pad areas 11 to package and test more ultrasonic chips, and the space utilization rate on the wafer 10 is high.

[0101] In summary, any one of the embodiments 1, 2, 3, and 4 of the above-mentioned examples of the present application can reduce the thickness difference at at least part of the edge of at least one predetermined shape and size of the acoustic layer 100 prepared compared to the thickness difference in the middle area of ​​the acoustic layer 100, thereby effectively improving the thickness uniformity of the prepared acoustic layer 100. As a result, the ultrasonic chip produced by the acoustic layer 100 prepared by the acoustic layer scheme of the present application has better performance. When the ultrasonic chip is used in an ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is better and the fingerprint recognition performance is also better.

[0102] It can be understood that the above contents are merely some optional embodiments of the preparation scheme of the acoustic layer in the embodiments of the present application, and they do not constitute any limitation to the embodiments of the present application.

[0103] To sum up, the preparation scheme of the acoustic layer in the embodiment of the present application can utilize the acoustic layer raw material and the silk screen plate 20 with at least one silk screen opening 21 to perform silk screen printing on the wafer 10, so that the acoustic layer raw material passes through the at least one silk screen opening 21 to form at least one acoustic material layer 30 on the wafer 10, wherein the area of ​​the acoustic material layer 30 is larger than the area of ​​the acoustic layer 100 of the predetermined shape and size, and then the at least one acoustic material layer 30 is segmented to prepare at least one acoustic layer 100 of the predetermined shape and size on the wafer 10, and the thickness uniformity of the prepared at least one acoustic layer 100 of the predetermined shape and size is good, and then the performance of the ultrasonic chip produced using the acoustic layer 100 prepared in this scheme is good. When the ultrasonic chip is used in the ultrasonic fingerprint module, the fingerprint image quality obtained by the ultrasonic fingerprint module is good, and the fingerprint recognition performance is also good.

[0104] Reference Figure 7 As shown, according to the second aspect of the embodiment of the present application, an ultrasonic chip 200 is provided, comprising: an acoustic layer 100 for generating an ultrasonic signal, the acoustic layer 100 being in a predetermined shape, wherein the acoustic layer 100 is prepared by the method described in the first aspect above.

[0105] Since the acoustic layer 100 in the ultrasonic chip 200 provided in the second aspect of the embodiment of the present application is prepared by the method for preparing the acoustic layer provided in the first aspect of the present application, the ultrasonic chip 200 has better performance.

[0106] Reference Figure 8 As shown, according to the third aspect of the embodiment of the present application, an ultrasonic fingerprint module 300 is provided, including: the ultrasonic chip 200 provided by the second aspect above.

[0107] Since the ultrasonic fingerprint module 300 provided in the third aspect of the embodiment of the present application includes the ultrasonic chip 200 provided in the second aspect, and the acoustic layer 100 in the ultrasonic chip 200 is prepared by the preparation method of the acoustic layer provided in the first aspect of the present application, the fingerprint image quality obtained by the ultrasonic fingerprint module 300 is better and the fingerprint recognition performance is also better.

[0108] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". It should be noted that the concepts of "first", "second", etc. mentioned in this application are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units. It should be noted that the modifications of "one" and "multiple" mentioned in this application are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing an acoustic layer, characterized in that: The acoustic layer is used to generate an ultrasonic signal for the ultrasonic chip, and the method comprises: Using an acoustic layer raw material and a screen printing plate with at least one screen opening, screen printing is performed on a wafer so that the acoustic layer raw material passes through the at least one screen opening to form a plurality of acoustic material layers arranged at intervals along a first direction on the wafer, wherein the area of ​​the acoustic material layer is larger than the area of ​​the acoustic layer of a predetermined shape and size; Slicing at least one acoustic material layer to prepare a plurality of acoustic layers of predetermined shapes and sizes on the wafer; A plurality of pad areas of ultrasonic chips are formed on the wafer, and after a plurality of acoustic material layers arranged at intervals along a first direction are formed on the wafer, at least one of the pad areas is not in contact with the acoustic material layer, and the pad areas of the plurality of ultrasonic chips are arranged in a plurality of rows along the first direction; After a plurality of acoustic material layers arranged in an interval along a first direction are formed on the wafer, two rows of the pad areas exist in the interval area between at least one group of adjacent two acoustic material layers; wherein, the at least one group of adjacent two acoustic layers and the two rows of the pad areas existing in the interval area between at least one group of adjacent two acoustic material layers can prepare two rows of ultrasonic chips.

2. The method according to claim 1, characterized in that The acoustic layer is rectangular in shape, and the length of the acoustic layer along the first direction is a first predetermined length A, and the length of the acoustic layer along the second direction is a second predetermined length B, and the first direction is perpendicular to the second direction; wherein, The first length C of the maximum inscribed rectangle of at least one of the acoustic material layers along the first direction and the first predetermined length A satisfy: C=A, and the second length D of the maximum inscribed rectangle of the acoustic material layer along the second direction and the second predetermined length B satisfy: D>B.

3. The method according to claim 1, characterized in that The acoustic layer is rectangular in shape, and the length of the acoustic layer along the first direction is a first predetermined length A, and the length of the acoustic layer along the second direction is a second predetermined length B, and the first direction is perpendicular to the second direction; wherein, The first length C of the maximum inscribed rectangle of at least one of the acoustic material layers along the first direction and the first predetermined length A satisfy: C>A, and the second length D of the maximum inscribed rectangle of the acoustic material layer along the second direction and the second predetermined length B satisfy: D>B.

4. The method according to claim 1, characterized in that: The acoustic layer is rectangular in shape, and the length of the acoustic layer along the first direction is a first predetermined length A, and the length of the acoustic layer along the second direction is a second predetermined length B, and the first direction is perpendicular to the second direction; wherein, The first length C of the maximum inscribed rectangle of at least one of the acoustic material layers along the first direction and the first predetermined length A satisfy: C>2A, and the second length D of the maximum inscribed rectangle of the acoustic material layer along the second direction and the second predetermined length B satisfy: D>B.

5. The method according to any one of claims 1 to 4, characterized in that After at least one of the acoustic material layers is divided, a plurality of acoustic layers with predetermined shapes and sizes are prepared.

6. The method according to any one of claims 1 to 4, characterized in that The forming of at least one acoustic material layer on the wafer comprises: forming a plurality of acoustic material layers arranged in parallel on the wafer.

7. An ultrasonic chip, characterized in that: include: An acoustic layer for generating an ultrasonic signal, wherein the acoustic layer has a predetermined shape and size, wherein the acoustic layer is prepared by the method according to any one of claims 1-6.

8. An ultrasonic fingerprint module, characterized in that: include: The ultrasonic chip as claimed in claim 7.

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