3d microphone flexible printed circuit board with hole reinforcement and manufacturing method thereof

Abstract

This invention discloses a 3D-reinforced microphone flexible circuit board and its fabrication method, comprising providing a flexible microphone substrate and a rigid pressing fixture; one side of the flexible microphone substrate is provided with 3D-reinforced holes, and the rigid pressing fixture is provided with at least one clearance opening; the side of the flexible microphone substrate with 3D-reinforced holes is attached to the surface of the rigid pressing fixture, such that at least one reinforcing through-hole on the 3D-reinforced holes corresponds to the position of the same number of clearance openings, forming a first stack; a rigid positioning structure is attached to the side of the first stack away from the 3D-reinforced holes, forming a second stack; the second stack is pressed, and the rigid pressing fixture and rigid positioning structure are peeled off from the pressed second stack to form the target flexible microphone circuit board. This invention ensures the flatness of the flexible board based on the clearance opening's clearance effect on the 3D reinforcement and the rigid support of the rigid pressing fixture and rigid positioning structure.

Description

Technical Field

[0001] This invention relates to the field of flexible circuit board manufacturing technology, specifically to a 3D microphone flexible circuit board with hole reinforcement and its manufacturing method. Background Technology

[0002] With the development of flexible printed circuits (FPCs), various sensing and functional components are increasingly being integrated and soldered onto FPCs. Microphones (MICs) are one such commonly used functional component. To ensure sound transmission quality, conventional FPC designs typically employ a closed circular ring (i.e., the MIC ring, made of gold, hence also called the MIC gold ring) and a single-layer PI (polyimide) structure with a central opening on the front side. Figure 1 As shown. In Figure 1 In the diagram, 1 represents the flexible microphone substrate, 11 represents the PI layer, 111 represents the microphone hole on the PI layer, 12 represents the first copper foil, 121 represents the first copper opening on the first copper foil, 13 represents the second copper foil, 131 represents the second copper opening on the second copper foil, 14 represents the 3D perforated reinforcement, 141 represents the reinforcing through-hole on the 3D perforated reinforcement, 15 represents the protective film, 151 represents the film opening on the protective film, 16 represents the reinforcing adhesive, 161 represents the adhesive opening on the reinforcing adhesive, 17 represents the ink layer, 171 represents the ink opening on the ink layer, 18 represents the MIC ring, and 4 represents the composite release film (composed of release film + filler film + release film). The closed MIC ring is soldered to the corresponding pads on the microphone in the subsequent assembly process to form a sealed sound-absorbing space. Sound enters the MIC through the holes in the single-layer PI and forms an electric current in the MIC. In actual production, when the rigidity of the flexible circuit board used on the back of the MIC is insufficient to support the MIC soldering, various materials and thicknesses of reinforcement (such as PI reinforcement, FR4 reinforcement, SUS steel reinforcement, etc.) are used on the back of the MIC as support to ensure that functional problems do not occur in subsequent applications. These supporting reinforcements have gradually been given more applications, requiring the positioning of other structural components. Therefore, reinforcement has evolved to include both planar support areas that ensure the flatness of the solder pads and areas with local three-dimensional shapes. This type of reinforcement is called 3D reinforcement. Figure 1 3D perforated reinforcement 14.

[0003] Whether it's planar reinforcement or this type of 3D reinforcement, a lamination process is required to press these support materials onto the flexible circuit board. Especially with SUS steel reinforcement, to ensure microphone transmission, SUS steel reinforcement is first perforated at the corresponding position of the microphone's sound transmission hole, resulting in a 3D structure appearing above the microphone's sound transmission hole, resembling a chimney. This suspended design easily leads to poor flatness of the microphone's gold ring after lamination, causing component floating and poor soldering issues after reflow assembly. When this suspended design cannot be avoided, the fast lamination method for planar reinforcement with holes is no longer suitable for the fast lamination and fabrication of 3D reinforced flexible circuit boards. Summary of the Invention

[0004] In view of this, the present invention provides a 3D perforated reinforced microphone flexible circuit board and its manufacturing method, so as to solve the problem of poor flatness leading to poor quality of the flexible circuit board when laminating 3D perforated reinforced microphone flexible circuit boards in the prior art.

[0005] This invention provides a method for fabricating a 3D perforated reinforced flexible microphone circuit board, comprising:

[0006] A flexible microphone substrate and a pre-fabricated rigid pressing fixture are provided; one side of the flexible microphone substrate is provided with a 3D perforated reinforcement, and the rigid pressing fixture is provided with at least one clearance opening; wherein, the 3D perforated reinforcement has a chimney shape, and the clearance opening is used to avoid the chimney shape on the 3D perforated reinforcement.

[0007] The side of the flexible microphone substrate with the 3D perforated reinforcement is attached to the surface of the rigid pressing fixture, such that at least one reinforcing through hole on the 3D perforated reinforcement corresponds to the position of the same number of the clearance openings, forming a first stack.

[0008] A rigid positioning structure is attached to the side of the first stack that is away from the 3D perforated reinforcement to form a second stack;

[0009] The second stack is pressed together, and the rigid pressing fixture and the rigid positioning structure on the pressed second stack are torn apart to form a target microphone flexible circuit board.

[0010] Optionally, before providing the microphone flexible substrate and the pre-fabricated rigid pressing fixture, the method further includes:

[0011] The rigid pressing fixture is fabricated having at least one of the aforementioned clearance openings.

[0012] Optionally, each of the clearance openings includes a first opening, a second opening, and a third opening corresponding to its position;

[0013] The fabrication of the rigid pressing fixture having at least the aforementioned clearance opening includes:

[0014] Provides a steel plate, a first rubber layer, and a first release film;

[0015] At least one first opening is formed on the steel plate, at least one second opening is formed on the first rubber layer, and at least one third opening is formed on the release film;

[0016] Wherein, the dimensions of the cross-section of each of the first openings, the dimensions of the cross-section of each of the corresponding second openings, and the dimensions of the cross-section of the corresponding third opening are all equal;

[0017] At least one first positioning hole is formed at the edge of the steel plate, at least one second positioning hole is formed at the edge of the first rubber layer, and at least one third positioning hole is formed at the edge of the first release film.

[0018] The number of the first positioning holes, the number of the second positioning holes, and the number of the third positioning holes are all equal, and all the first positioning holes correspond to all the second positioning holes, and all the second positioning holes correspond to all the third positioning holes.

[0019] Based on at least one first positioning hole and the corresponding second positioning hole and the corresponding third positioning hole, the first rubber layer and the first release film are sequentially attached to the surface of the steel plate using at least one positioning pin to form the rigid pressing clamp.

[0020] Optionally, before providing the microphone flexible substrate and the pre-fabricated rigid pressing fixture, the method further includes:

[0021] Fabricate the flexible microphone substrate with the 3D perforated reinforcement on one side;

[0022] The 3D perforated reinforcement is provided with at least one of the reinforcement through holes;

[0023] At least one microphone hole is provided on the flexible microphone substrate at a position corresponding to each of the reinforcing through holes; the flexible microphone substrate is also provided on the side away from the 3D hole reinforcement, which is provided with the same number of MIC rings as the reinforcing through holes, and all the reinforcing through holes correspond to the positions of all the MIC rings.

[0024] Optionally, all the reinforcing through holes correspond to all the third opening positions, and the cross-sectional dimension of each third opening is larger than the cross-sectional dimension of the corresponding reinforcing through hole.

[0025] Optionally, the difference between the cross-sectional dimension of each of the third openings and the cross-sectional dimension of the corresponding reinforcing through hole is 0.1 to 0.5 mm.

[0026] Optionally, the side of the flexible microphone substrate with the 3D perforated reinforcement is attached to the surface of the rigid pressing fixture, such that at least one reinforcing through-hole on the 3D perforated reinforcement corresponds to the position of the same number of clearance openings, forming a first stack, including:

[0027] The side of the flexible microphone substrate with the 3D perforated reinforcement is attached to the side of the rigid pressing fixture with the first release film, so that each of the first opening, each of the second opening, each of the third opening, each of the reinforcing through holes and each of the MIC rings are in corresponding positions to form the first stack.

[0028] Optionally, the rigid positioning structure includes a second release film, an aluminum plate, and a second rubber layer arranged sequentially.

[0029] The step of attaching a rigid positioning structure to the side of the first stack opposite to the 3D perforated reinforcement to form a second stack includes:

[0030] The side of the rigid positioning structure with the second release film is attached to the side of the first stack with the MIC ring to form the second stack.

[0031] Optionally, the step of pressing the second stack and tearing off the rigid pressing fixture and the rigid positioning structure on the pressed second stack to form the target microphone flexible circuit board includes:

[0032] The second stack is pressed using a high-speed press according to the preset pressing parameters;

[0033] The second stacked structure after pressing is removed from the press machine, and the rigid pressing fixture and the rigid positioning structure on the second stacked structure are torn apart to form the target microphone flexible circuit board.

[0034] In addition, the present invention also provides a 3D perforated reinforced microphone flexible circuit board, which is manufactured using the aforementioned method for manufacturing a 3D perforated reinforced microphone flexible circuit board.

[0035] The beneficial effects of this invention are as follows: A rigid pressing fixture is attached to the side of the flexible microphone substrate with 3D perforated reinforcement, and a rigid positioning structure is attached to the side opposite to the 3D perforated reinforcement. The resulting new pressing stack (i.e., the second stack) ensures the flatness of the flexible microphone substrate during subsequent pressing due to the rigid support of the rigid pressing fixture and the rigid positioning structure. Furthermore, during the formation of the second stack, at least one clearance opening on the rigid pressing fixture provides clearance for the 3D perforated reinforcement, ensuring both the support of the 3D perforated reinforcement on the back of the entire flexible microphone substrate and the proper functioning of the reinforcement. At least one reinforcing through-hole on the flexible board enables the microphone hole to transmit sound. Furthermore, it effectively prevents the chimney-shaped three-dimensional structure above the microphone hole from being exposed during subsequent lamination, reducing lamination damage to this structure, lowering the lamination force, and ensuring the structure does not dent or flatten. Compared to traditional flexible board manufacturing methods with perforated reinforcement, no composite release film is needed for support, further ensuring the flatness of the flexible board and the normal functioning of each component. Based on the specific lamination structure of this invention, the flatness of the microphone flexible board during lamination is effectively guaranteed, improving the quality of the flexible board. Attached Figure Description

[0036] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0037] Figure 1 A cross-sectional view of a conventional microphone flexible circuit board with perforation reinforcement is shown.

[0038] Figure 2 A flowchart illustrating a method for fabricating a 3D perforated reinforced flexible microphone circuit board according to an embodiment of the present invention is shown.

[0039] Figure 3-1 The diagram shows a top view of the rigid pressing fixture in Embodiment 1 of the present invention.

[0040] Figure 3-2 A cross-sectional view of the rigid pressing fixture in Embodiment 1 of the present invention is shown;

[0041] Figure 3-3 The diagram shows a top view of the steel plate in the rigid pressing fixture of Embodiment 1 of the present invention;

[0042] Figure 4 A cross-sectional view of a flexible microphone substrate according to Embodiment 1 of the present invention is shown.

[0043] Figure 5 A cross-sectional view of another flexible microphone substrate according to Embodiment 1 of the present invention is shown;

[0044] Figure 6 A diagram showing the size relationship between the cross-sectional dimensions of any third opening in Embodiment 1 of the present invention and the cross-sectional dimensions of its corresponding reinforcing through hole is provided.

[0045] Figure 7 A cross-sectional view of the flexible circuit board of the target microphone in Embodiment 1 of the present invention is shown.

[0046] Figure 8 The diagram shows the external structure of the flexible circuit board for the target microphone in Embodiment 1 of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. Microphone flexible substrate; 2. Rigid pressing clamp; 3. Rigid positioning structure; 4. Composite release film; 5. Lower chassis; 6. Upper airbag.

[0049] 11. PI layer, 12. First copper foil, 13. Second copper foil, 14. 3D perforated reinforcement, 15. Protective film, 16. Reinforcing adhesive, 17. Ink layer, 18. MIC ring, 21. Steel plate, 22. First rubber layer, 23. First release film, 24. Positioning pin, 31. Aluminum plate, 32. Second rubber layer, 33. Second release film;

[0050] 111. Microphone hole; 121. First copper opening; 131. Second copper opening; 141. Reinforcing through hole; 151. Membrane opening; 161. Adhesive opening; 171. Ink opening; 211. First opening; 212. First positioning hole; 221. Second opening; 231. Third opening. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Example 1

[0053] A method for fabricating a 3D perforated reinforced flexible circuit board for microphones, such as... Figure 2 As shown, it includes the following steps:

[0054] S1, a flexible microphone substrate and a pre-fabricated rigid pressing fixture are provided; one side of the flexible microphone substrate is provided with a 3D perforated reinforcement, and the rigid pressing fixture is provided with at least one clearance opening; wherein, the 3D perforated reinforcement has a chimney shape, and the clearance opening is used to avoid the chimney shape on the 3D perforated reinforcement.

[0055] Preferably, before S1, the following is also included:

[0056] The rigid pressing fixture is fabricated having at least one of the aforementioned clearance openings.

[0057] Before forming the first stack, a rigid pressing fixture is first made. This is beneficial to improve the flatness of the flexible board by relying on the rigid support of the pressing fixture.

[0058] Preferably, each of the clearance openings includes a first opening, a second opening, and a third opening corresponding to its position;

[0059] The fabrication of the rigid pressing fixture having at least the aforementioned clearance opening includes:

[0060] Provides a steel plate, a first rubber layer, and a first release film;

[0061] At least one first opening is formed on the steel plate, at least one second opening is formed on the first rubber layer, and at least one third opening is formed on the release film;

[0062] Wherein, the dimensions of the cross-section of each of the first openings, the dimensions of the cross-section of each of the corresponding second openings, and the dimensions of the cross-section of the corresponding third opening are all equal;

[0063] At least one first positioning hole is formed at the edge of the steel plate, at least one second positioning hole is formed at the edge of the first rubber layer, and at least one third positioning hole is formed at the edge of the first release film.

[0064] The number of the first positioning holes, the number of the second positioning holes, and the number of the third positioning holes are all equal, and all the first positioning holes correspond to all the second positioning holes, and all the second positioning holes correspond to all the third positioning holes.

[0065] Based on at least one first positioning hole and the corresponding second positioning hole and the corresponding third positioning hole, the first rubber layer and the first release film are sequentially attached to the surface of the steel plate using at least one positioning pin to form the rigid pressing clamp.

[0066] The rigid pressing fixture described above uses a steel plate as its core component, providing excellent rigid support to support the flexible substrate during subsequent pressing, preventing bending and ensuring flatness. The first rubber layer effectively controls the flow of adhesive on the 3D perforated reinforcement surface of the microphone flexible substrate during subsequent pressing to form the first stack, ensuring the cleanliness of the first stack. The first release film acts as a buffer, preventing damage to the flexible substrate during pressing. During the fabrication of the rigid pressing fixture, at least one first opening, a second opening, and a third opening formed on the steel plate, the first rubber layer, and the first release film facilitate the formation of a precisely aligned rigid pressing fixture, ensuring its rigid support and the avoidance function during subsequent pressing. Furthermore, the avoidance function of the openings prevents damage to the 3D perforated reinforcement structure on the flexible substrate during pressing, ensuring the normal functioning of the microphone flexible substrate. After at least one first opening, a second opening, and a third opening are formed, a rigid pressing fixture with precise positioning is further facilitated by at least one first positioning hole on the edge of the steel plate, at least one second positioning hole on the edge of the first rubber layer, at least one third positioning hole on the edge of the first release film, and at least one positioning pin.

[0067] It should be noted that when mass-producing flexible circuit boards for target microphones using a rigid pressing fixture, the number of clearance openings (including the first, second, and third openings) on the rigid pressing fixture is multiple. Each clearance opening avoids the 3D perforated reinforcement of each target microphone flexible circuit board. After pressing and tearing off the auxiliary materials (including the rigid pressing fixture and rigid positioning structure), single-piece separation is then performed, enabling the production of multiple target microphone flexible circuit boards. However, when producing single target microphone flexible circuit boards using a rigid pressing fixture, the number of clearance openings (including the first, second, and third openings) on the rigid pressing fixture can be multiple (in which case one clearance opening can be used to avoid the 3D perforated reinforcement in the single target microphone flexible circuit board) or only one (this single clearance opening is used to avoid the 3D perforated reinforcement in the single target microphone flexible circuit board). Therefore, the number of clearance openings depends on the specific production situation, and the dimensions of the first, second, and third openings among the clearance openings also depend on the specific circumstances.

[0068] Specifically, the top view structural diagram of the rigid pressing fixture manufactured in this embodiment is as follows: Figure 3-1 As shown, the cross-sectional structural diagram of the rigid pressing fixture is as follows: Figure 3-2 As shown, the top view of its bottom steel plate structure is as follows: Figure 3-3 As shown. In Figures 3-1 to 3-3In the diagram, 2 represents a rigid pressing fixture, 21 represents a steel plate, 211 represents the first opening on the steel plate, 212 represents the first positioning hole on the steel plate, 22 represents the first rubber layer, 221 represents the second opening on the first rubber layer, 23 represents the first release film, 231 represents the third opening on the first release film, and 24 represents a positioning pin penetrating the first positioning hole, the corresponding second positioning hole, and the corresponding third positioning hole. Since each first opening corresponds to the corresponding second opening in position and has the same size, and each second opening corresponds to the corresponding third opening in position and has the same size, therefore... Figure 3-1 Facing the first release film, only several third openings 231 are shown (the corresponding second openings 221 and first openings 211 are not shown); similarly, since each first positioning hole corresponds to its second and third positioning holes, and the positioning pin passes through the first positioning hole, the corresponding second positioning hole, and the corresponding third positioning hole, therefore... Figure 3-1 Only four positioning pins 24 are shown (i.e., the first positioning hole, the second positioning hole and the third positioning hole on the four positioning pins are not shown), located at the four corners of the rigid pressing fixture 2; Figure 3-3 The bottom steel plate 21, several first openings 211 on the steel plate 21, and four first positioning holes 212 on the steel plate 21 are shown. Figure 3-2 It shows any third opening 231 and its corresponding second opening 221 and first opening 211, as well as two positioning pins 24. Other unshown parts are similar to the shown parts.

[0069] Preferably, before S1, it further includes:

[0070] Fabricate the flexible microphone substrate with the 3D perforated reinforcement on one side;

[0071] The 3D perforated reinforcement is provided with at least one of the reinforcement through holes;

[0072] At least one microphone hole is provided on the flexible microphone substrate at a position corresponding to each of the reinforcing through holes; the flexible microphone substrate is also provided on the side away from the 3D hole reinforcement, which is provided with the same number of MIC rings as the reinforcing through holes, and all the reinforcing through holes correspond to the positions of all the MIC rings.

[0073] By fabricating a flexible microphone substrate with 3D perforated reinforcement on one side, it is beneficial to improve the efficiency of subsequent bonding, stacking, and lamination processes.

[0074] Specifically, the flexible microphone substrate can be a single-layer board (a flexible circuit board with only one layer of copper foil), a double-layer board (a flexible circuit board with two layers of copper foil), or a multi-layer board (a flexible circuit board with two or more layers of copper foil). This embodiment will use a double-layer board with two layers of copper foil as an example for illustration. Figure 4 As shown and Figure 5 As shown. In Figure 4 and Figure 5 In the diagram, 1 represents the flexible microphone substrate, 11 represents the PI layer, 111 represents the microphone hole on the PI layer, 12 represents the first copper foil, 121 represents the first copper opening on the first copper foil, 13 represents the second copper foil, 131 represents the second copper opening on the second copper foil, 14 represents 3D via reinforcement, and 141 represents the reinforcement via on the 3D via reinforcement. Figure 4 In the example of fabricating a single-chip flexible circuit board for a target microphone, the 3D reinforced 14 with a hole has a reinforcing through-hole 141, and a microphone hole 111 is provided at a position corresponding to the reinforcing through-hole 141 on the flexible microphone substrate 1 (of course, there can be multiple microphone holes provided at the positions corresponding to the reinforcing through-hole 141 on the flexible microphone substrate 1, for example...). Figure 5 As shown, there are three microphone holes 111 corresponding to one reinforcing through hole 141.

[0075] Preferably, all the reinforcing through holes correspond to all the third opening positions, and the cross-sectional dimension of each third opening is larger than the cross-sectional dimension of the corresponding reinforcing through hole.

[0076] When the cross-sectional dimension of the third opening is larger than the cross-sectional dimension of the corresponding reinforcing through hole, the dimensions of the first opening and the second opening are also larger than the cross-sectional dimension of the corresponding reinforcing through hole. This can effectively avoid deviation between the microphone flexible substrate and the rigid pressing fixture during the attachment process due to attachment error, thus preventing the 3D hole reinforcement in the microphone flexible substrate from being misaligned.

[0077] Preferably, the difference between the cross-sectional dimension of each of the third openings and the cross-sectional dimension of the corresponding reinforcing through hole is 0.1 to 0.5 mm.

[0078] The aforementioned size limitations ensure the smooth implementation of the clearance function. In this embodiment, the relationship between the cross-sectional dimensions of any third opening and the corresponding reinforcing through-hole is as follows: Figure 6 As shown, in Figure 6 In the middle, the difference between the cross-sectional dimension of the third opening 231 and the cross-sectional dimension of the corresponding reinforcing through hole 141 is Δ / 2 + Δ / 2 = Δ, where Δ / 2 is the difference on one side.

[0079] Specifically, in this embodiment, the first opening, second opening, third opening, first positioning hole, second positioning hole, and third positioning hole are all formed using conventional processes, such as laser drilling. The dimensions of the first positioning hole, second positioning hole, and third positioning hole depend on the specific circumstances.

[0080] Specifically, this embodiment uses the fabrication of a single-chip target microphone flexible circuit board as an example for illustration. Figure 4 and Figure 5 In the design, the flexible microphone substrate 1 is a double-layer board, including a first copper foil 12, a PI layer 11, and a second copper foil 13. A 3D perforated reinforcement 14 is located on one side of the second copper foil 13, and a reinforcement through-hole 141 is provided on the 3D perforated reinforcement 14; as shown Figure 4 and Figure 5 As shown, a protective film 15 and a reinforcing adhesive 16 are sequentially bonded to one side of the second copper foil 13. The protective film 15 is located between the second copper foil 13 and the reinforcing adhesive 16. The 3D perforated reinforcement 14 is bonded together with the protective film 15 via the reinforcing adhesive 16. The reinforcing adhesive 16 has an adhesive opening 161 before bonding, and the protective film 15 has a film opening 151 before bonding. A microphone hole 111 is disposed on the PI layer 11, and a MIC ring 18 is disposed on the first copper foil 12. The inner edge of the MIC ring 18 forms a first copper opening 121 on the first copper foil 12. The second copper foil 13 has a second copper opening 131 corresponding to the first copper opening 121. The first copper opening, microphone hole, second copper opening, film opening, adhesive opening, and reinforcing through-hole in the aforementioned flexible microphone substrate all correspond to the position of the second opening, thus forming a chimney-shaped three-dimensional reinforcing structure on one side of the microphone hole.

[0081] like Figure 2 As shown in Figure S2, the side of the microphone flexible substrate with the 3D perforated reinforcement is attached to the surface of the rigid pressing fixture, such that at least one reinforcing through hole on the 3D perforated reinforcement corresponds to the position of the same number of the clearance openings, forming a first stack.

[0082] Preferably, S2 includes:

[0083] The side of the flexible microphone substrate with the 3D perforated reinforcement is attached to the side of the rigid pressing fixture with the first release film, so that each of the first opening, each of the second opening, each of the third opening, each of the reinforcing through holes and each of the MIC rings are in corresponding positions to form the first stack.

[0084] The 3D perforated reinforcement side is attached to the first release film. By utilizing the positional correspondence between each first opening, each second opening, each third opening, each reinforcement through hole, and each MIC ring, the microphone holes and 3D perforated reinforcement in the microphone flexible substrate are effectively avoided in the subsequent pressing process. This ensures the pressing quality of the 3D perforated reinforcement and facilitates subsequent fast pressing to produce high-quality microphone electronic products.

[0085] Specifically, for Figure 4 and Figure 5The microphone flexible substrate shown is positioned with the MIC ring 18 facing upwards and the 3D perforated reinforcement 14 facing downwards, placed close to the first release film 23 of the rigid pressing clamp 2, as shown. Figure 7 As shown.

[0086] like Figure 2 As shown in Figure S3, a rigid positioning structure is attached to the side of the first stack away from the 3D perforated reinforcement to form a second stack.

[0087] Preferably, the rigid positioning structure includes a second release film, an aluminum plate, and a second rubber layer arranged sequentially.

[0088] S3 includes:

[0089] The side of the rigid positioning structure with the second release film is attached to the side of the first stack with the MIC ring to form the second stack.

[0090] The aforementioned rigid positioning structure serves two purposes: firstly, it provides rigid support to the first stack on one side, ensuring the microphone flexible substrate remains flat during subsequent lamination; secondly, it also positions the first stack to facilitate precise subsequent lamination. The second rubber layer controls adhesive flow from the microphone flexible substrate, preventing contamination of the entire flexible board and improving cleanliness. The second release film acts as a buffer between the aluminum plate and the microphone flexible substrate, ensuring that even minor defects in the aluminum plate or the second rubber layer do not affect the quality of the core microphone flexible substrate.

[0091] Specifically, for Figure 4 and Figure 5 The microphone flexible substrate shown has the second release film of the rigid positioning structure placed face down on the first copper foil of the microphone flexible substrate, as shown. Figure 7 As shown. In Figure 7 In the diagram, 3 represents the rigid positioning structure, 31 represents the aluminum plate, 32 represents the second rubber layer, and 33 represents the second release film.

[0092] It should be noted that in this embodiment, a rigid positioning structure including a second release film, an aluminum plate, and a second rubber layer can be prefabricated and then placed on the first copper foil to form a second stacked structure; alternatively, the second release film can be placed on the first copper foil first, then the aluminum plate can be placed on the second release film, and finally the second rubber layer can be placed on the aluminum plate, that is, each layer of the rigid positioning structure is sequentially stacked on the first copper foil to form a second stacked structure.

[0093] Specifically, in one embodiment, before attaching the rigid positioning structure to the first copper foil, a solder resist ink process is used to treat the first copper foil, forming an ink layer on the surface of the first copper foil. Ink openings are then formed on the ink layer corresponding to the reinforcing through-holes on the 3D perforated reinforcement. Figure 4 and Figure 5 The ink layer 17 and ink opening 171 are shown.

[0094] like Figure 2 As shown, in step S4, the second stack is pressed together, and the rigid pressing fixture and the rigid positioning structure on the pressed second stack are torn apart to form a target microphone flexible circuit board.

[0095] Preferably, S4 includes:

[0096] The second stack is pressed using a high-speed press according to the preset pressing parameters;

[0097] The second stacked structure after pressing is removed from the press machine, and the rigid pressing fixture and the rigid positioning structure on the second stacked structure are torn apart to form the target microphone flexible circuit board.

[0098] By using a high-speed press, pressing is performed based on the second stack, and the rigid pressing fixture and rigid positioning structure are torn off after pressing, which can facilitate the efficient formation of a target microphone flexible circuit board with excellent flatness.

[0099] The preset pressing parameters include pressing time, pressing temperature, and pressing pressure. The specific numerical ranges of pressing time, pressing temperature, and pressing pressure are all conventional parameter ranges. The specific operation process for tearing off the auxiliary materials (i.e., the rigid pressing fixture and the rigid positioning structure) also adopts conventional technology, which will not be described in detail in this embodiment.

[0100] Specifically, the cross-sectional view of the second stack during pressing in embodiment S4 is shown below. Figure 7 As shown, in Figure 7 In the middle, the lower structure 5 represents the lower chassis of the high-pressure press, and the upper structure 6 represents the upper airbag of the high-pressure press. In a specific embodiment of this example, the external structural diagram of the target microphone flexible circuit board obtained after pressing and tearing in S4 is shown below. Figure 8 As shown, from Figure 8 It can be seen that the flatness of the target microphone flexible circuit board is good under 3D hole reinforcement. Figure 8 The bright white component with bends in the middle is the 3D perforated reinforcement, and the bottom of it is the corresponding reinforcement through hole.

[0101] In this embodiment, the method for fabricating the 3D-reinforced microphone flexible circuit board involves attaching a rigid pressing fixture to the side of the flexible microphone substrate with the 3D-reinforced hole and a rigid positioning structure to the side opposite to the 3D-reinforced hole, forming a new pressing stack (i.e., a second stack). The rigid pressing fixture and the rigid positioning structure provide strong support, ensuring the flexible microphone substrate remains flat during subsequent pressing, thus guaranteeing the flatness of the flexible board to a certain extent. Furthermore, during the formation of the second stack, at least one clearance opening on the rigid pressing fixture provides clearance for the 3D-reinforced hole, ensuring the 3D-reinforced hole supports the entire back side of the flexible microphone substrate. It also ensures that at least one reinforcing through-hole on the 3D perforated reinforcement can achieve the sound transmission effect of the microphone hole; on the other hand, it can also effectively ensure that during subsequent lamination, the chimney-shaped three-dimensional structure on the flexible board above the microphone hole is avoided, reducing lamination damage to the three-dimensional structure on the flexible board, reducing lamination force, and ensuring that the three-dimensional structure does not dent or flatten; compared with the traditional flexible board manufacturing method with perforated reinforcement, there is no need for composite release film to participate in the support, which can further ensure the flatness of the flexible board and ensure the normal functioning of each component on the flexible board; based on the specific lamination stacking structure of this embodiment, the lamination flatness of the microphone flexible board can be effectively guaranteed, and the quality of the flexible board can be improved.

[0102] Example 2

[0103] A 3D perforated reinforced flexible microphone circuit board is manufactured using the fabrication method of the 3D perforated reinforced flexible microphone circuit board in Embodiment 1.

[0104] The 3D perforated reinforced microphone flexible circuit board of this embodiment, based on a specific lamination structure, can form a chimney-shaped 3D perforated reinforcement while ensuring excellent flatness and high-quality flexible board.

[0105] The fabrication method of the 3D perforated reinforced microphone flexible circuit board in this embodiment is the same as that described in Embodiment 1. For details not covered in this embodiment, please refer to Embodiment 1 and... Figures 1 to 8 The specific details will not be repeated here.

[0106] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for manufacturing a 3D hole-reinforced microphone flexible wiring board, characterized by, The method comprises the following steps: Providing a microphone flexible substrate and a pre-made rigid press-fit jig; one side of the microphone flexible substrate is provided with a 3D hole-reinforced structure, and the rigid press-fit jig is provided with at least one avoidance opening; wherein the 3D hole-reinforced structure has a chimney shape, and the avoidance opening is used to avoid the chimney shape on the 3D hole-reinforced structure; Attaching one side of the microphone flexible substrate provided with the 3D hole-reinforced structure to the surface of the rigid press-fit jig, so that at least one reinforcing through hole on the 3D hole-reinforced structure corresponds to the same number of avoidance opening positions, forming a first stack; Attaching a rigid positioning structure to the side of the first stack away from the 3D hole-reinforced structure, forming a second stack; Pressing the second stack, and tearing off the rigid press-fit jig and the rigid positioning structure on the second stack after pressing, to form a target microphone flexible circuit board.

2. The method of claim 1, wherein the 3D hole reinforced microphone flex circuit board is made by the steps of: Before the step of providing the microphone flexible substrate and the pre-made rigid press-fit jig, the method further comprises the following steps: ​ Making the rigid press-fit jig provided with at least one avoidance opening.

3. The method of claim 2, wherein the 3D hole-plated reinforced microphone flex circuit board is made by: Each avoidance opening comprises a first opening, a second opening and a third opening corresponding in position; The step of making the rigid press-fit jig provided with at least one avoidance opening comprises the following steps: Providing a steel plate, a first rubber layer and a first release film; Forming at least one first opening on the steel plate, at least one second opening on the first rubber layer, and at least one third opening on the release film; Wherein the size of the cross section of each first opening, the size of the cross section of each corresponding second opening, and the size of the cross section of the corresponding third opening are equal; Forming at least one first positioning hole on the edge of the steel plate, at least one second positioning hole on the edge of the first rubber layer, and at least one third positioning hole on the edge of the first release film; Wherein the number of first positioning holes, the number of second positioning holes and the number of third positioning holes are equal, all the first positioning holes correspond to all the second positioning holes in position, and all the second positioning holes correspond to all the third positioning holes in position; Based on at least one first positioning hole and the corresponding second positioning hole and the corresponding third positioning hole, the first rubber layer and the first release film are sequentially attached to the surface of the steel plate by using at least one positioning needle, to form the rigid press-fit jig.

4. The method of manufacturing a 3D via reinforced microphone flex circuit board of claim 3, wherein, Before the step of providing the microphone flexible substrate and the pre-made rigid press-fit jig, the method further comprises the following steps: Making the microphone flexible substrate provided with the 3D hole-reinforced structure on one side; Wherein the 3D hole-reinforced structure is provided with at least one reinforcing through hole; The microphone flexible substrate is provided with at least one microphone hole at a position corresponding to each reinforcing through hole, and is further provided with the same number of MIC rings as the reinforcing through holes on the side away from the 3D hole-reinforced structure, and all the reinforcing through holes correspond to all the MIC rings in position.

5. The method of manufacturing a 3D via reinforced microphone flex circuit board of claim 4, wherein, All the reinforcing through holes correspond to all the third opening positions, and the size of the cross section of each third opening is greater than the size of the cross section of the corresponding reinforcing through hole.

6. The method of manufacturing a 3D via reinforced microphone flex circuit board of claim 5, wherein, The difference between the size of the cross section of each third opening and the size of the cross section of the corresponding reinforcing through hole is 0.1-0.5 mm.

7. The method of claim 5, wherein the 3D hole reinforced microphone flex circuit board is made by the steps of: The side of the microphone flexible substrate provided with the 3D hole-reinforced is attached to the surface of the rigid pressing clamp, so that at least one reinforcing through hole on the 3D hole-reinforced corresponds to the same number of avoidance opening positions, forming a first stack, comprising: ​ The side of the microphone flexible substrate provided with the 3D hole-reinforced is attached to the side of the rigid pressing clamp provided with the first release film, so that each first opening, each second opening, each third opening, each reinforcing through hole and each MIC ring are positionally corresponding, forming the first stack.

8. The method of manufacturing a 3D via reinforced microphone flex circuit board of claim 4, wherein, The rigid positioning structure comprises a second release film, an aluminum plate and a second rubber layer arranged in sequence; The rigid positioning structure is attached to the side of the first stack provided with the MIC ring, forming a second stack, comprising: The side of the rigid positioning structure provided with the second release film is attached to the side of the first stack provided with the MIC ring, forming the second stack.

9. The method of manufacturing a 3D hole-featured reinforced microphone flex circuit board according to any one of claims 1 to 8, wherein, The second stack is pressed, and the rigid pressing clamp and the rigid positioning structure on the second stack after pressing are torn off, forming a target microphone flexible circuit board, comprising: The second stack is pressed according to the preset pressing parameters by using a fast pressing machine; The second stack after pressing is taken off from the fast pressing machine, and the rigid pressing clamp and the rigid positioning structure on the second stack after pressing are torn off, forming the target microphone flexible circuit board.

10. A 3D hole reinforced microphone flexible wiring board, characterized by, The microphone flexible circuit board is made by using the manufacturing method of the 3D hole-reinforced microphone flexible circuit board according to any one of claims 1-9. The microphone flexible circuit board is made by using the manufacturing method of the 3D hole-reinforced microphone flexible circuit board according to any one of claims 1-9.

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