Flattening device and printed circuit board

Abstract

The application provides a flattening device and a printed circuit board, wherein the flattening device is used for tin ball secondary flattening of a multi-layer printed circuit board, and the flattening device comprises: a first platform used for placing a component to be flattened; and a second platform which is arranged in a spaced manner with the first platform, and a protruding pressing head is arranged on a side end face of the second platform facing the first platform, and the protruding pressing head cooperates with the first platform to flatten the component to be flattened; wherein the protruding pressing head is arranged at different positions of the second platform based on tin balls of different sizes in the multi-layer printed circuit board. In the above manner, the tin balls with small sizes after the first flattening are flattened to increase the sizes of the corresponding tin balls, so that the difference between the tin balls in the printed circuit is effectively reduced.

Description

Technical Field

[0001] This application relates to the field of printed circuit board technology, and in particular to a flattening device and a printed circuit board. Background Technology

[0002] A PCB (printed circuit board) is a crucial component in the electronics industry, serving as the support for electronic components and the carrier for their electrical interconnections. However, current technologies often suffer from uneven thickness during the fabrication of multilayer PCBs. Consequently, the size variation of solder balls during PCB fabrication can be significant, negatively impacting the yield rate of multilayer PCBs. Utility Model Content

[0003] This application provides a flattening device to solve the problem of excessively large size differences of solder balls in printed circuit boards in the prior art.

[0004] To address the aforementioned technical problems, this application provides a flattening device for secondary flattening of solder balls on multilayer printed circuit boards, comprising: a first platform for placing the component to be flattened; and a second platform spaced apart from the first platform, wherein a raised pressure head is provided on one end face of the second platform facing the first platform, the raised pressure head cooperating with the first platform to flatten the component to be flattened; wherein the raised pressure head is positioned at different locations on the second platform based on solder balls of different sizes in the printed circuit board.

[0005] The distance between the edge of the protruding pressure head and the edge of the second platform is the same as the distance between the small solder ball and the edge of the second platform.

[0006] The projection of the protruding pressure head on the second platform can be any one of a rectangle, triangle, ring, or circle.

[0007] The height of the raised pressure head is half the size difference between the large and small solder balls.

[0008] The adjacent edges of the protruding pressure head are rounded.

[0009] The length of the edge of the protruding pressure head shall not exceed 4mm.

[0010] Among them, the raised pressure head corresponds to the small-sized solder ball in the printed circuit board, and the large-sized solder ball corresponds to the area outside the raised pressure head on the second platform.

[0011] The plane in which the protruding pressure head faces the first platform is arranged parallel to the plane in which the first platform faces the protruding pressure head.

[0012] To address the aforementioned problems, this application also provides a printed circuit board, which is manufactured using the flattening device described in any of the above claims.

[0013] The printed circuit board has several solder balls arranged on one side and ink formed on the other side.

[0014] The beneficial effects of this application are as follows: Unlike the prior art, this application places the component to be flattened on the first platform and sets a raised pressure head on the side end face of the second platform facing the first platform, thereby flattening the component to be flattened. The raised pressure head is set at different positions on the second platform based on solder balls of different sizes in the multilayer printed circuit. This allows the raised pressure head to be set to correspond to the smaller solder balls in the printed circuit, so as to flatten the smaller solder balls after the first flattening, thereby increasing the size of the corresponding solder balls and effectively reducing the difference between solder balls in the printed circuit. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an embodiment of the flattening device of this application;

[0016] Figure 2 This is a schematic diagram of the connection between the protruding pressure head and the second platform in this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0019] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0020] Please see Figure 1 , Figure 1 This is a schematic diagram of an embodiment of the flattening device provided in this application.

[0021] This application provides a flattening device. For example... Figure 1 As shown, the flattening device of this embodiment is used for secondary flattening of solder balls 22 in a multilayer printed circuit board 21, and includes: a first platform 10, a second platform 30, and a raised pressure head 31. The first platform 10 is used to place the component 20 to be flattened. The second platform 30 is spaced apart from the first platform 10. The raised pressure head 31 is provided on the end face of the second platform 30 facing the first platform 10. The raised pressure head 31 cooperates with the first platform 10 to flatten the component 20 to be flattened. The raised pressure head 31 is positioned at different locations on the second platform 30 based on solder balls 22 of different sizes in the multilayer printed circuit board 21. In this multilayer printed circuit board 21, the solder balls 22 are solder balls that have undergone one flattening process. Because the thickness of the multilayer printed circuit board 21 is uneven during lamination, the solder balls 22 flattened during lamination have different sizes, meaning their projected sizes on the multilayer printed circuit board 21 vary. This results in a large size difference in the flattened solder balls 22 on the printed circuit board 21, affecting the performance of the printed circuit. Therefore, after the printed circuit board 21 is flattened once, the solder balls 22 in the multilayer printed circuit board 21 need to be flattened again to flatten the smaller solder balls 22 from the first flattening. Specifically, the component to be flattened 20 can be the multilayer printed circuit board 21 containing the solder balls 22.

[0022] In an optional embodiment, the flattening device includes a first platform 10 and a second platform 30. The opposing end faces of the first platform 10 and the second platform 30 can be used for secondary flattening of solder balls 22 in a multilayer printed circuit board 21. The first platform 10 is used to place the component 20 to be flattened, and a protruding pressure head 31 is provided on the side end face of the second platform 30 facing the first platform 10. The component 20 to be flattened is placed between the side end face of the protruding pressure head 31 facing the first platform 10 and the first platform 10, thereby flattening the component 20 through the first platform 10 and the pressure head component. When placing the printed circuit board 21 with solder balls 22 on the first platform 10, the side end face with solder balls 22 can face the first platform 10.

[0023] In an optional embodiment, the raised pressure head 31 is positioned at different locations on the second platform 30 based on solder balls 22 of different sizes in the multilayer printed circuit board 21. That is, because the printed circuit board 21 itself has uneven thickness during fabrication, after the solder balls 22 undergo the first flattening, the size of some solder balls 22 on the printed circuit board 21 is relatively small, and the size of others is relatively large. In other words, the smaller solder balls 22 have a smaller projected size on the printed circuit board 21, and the larger solder balls 22 have a larger projected size. Obviously, the solder balls 22 on the printed circuit board 21 are of the same size before flattening; therefore, after the first flattening, the uneven thickness of the printed circuit board 21 leads to different sizes of the solder balls 22. In order to ensure that the size difference of the solder balls 22 on the printed circuit board 21 is small, the solder balls 22 on the printed circuit board 21 need to be flattened for the first time. The smaller solder balls 22 can be flattened for the second time to reduce the size difference of the solder balls 22 on the printed circuit board 21.

[0024] After obtaining the printed circuit board 21 with solder balls 22 after one flattening, the size of the solder balls 22 in the printed circuit can be detected by AOI (Automated Optical Inspection). Specifically, Bump AOI (Bump Automated Optical Inspection) is used to inspect the printed circuit board 21 through automatic optical inspection, thereby obtaining the size of the solder balls 22 in the printed circuit board 21. This allows for the determination of solder balls 22 of different sizes in the printed circuit board 21. The detected solder ball 22 sizes are then transmitted to JMP (JMP Statistical Discovery Software) for data analysis, thereby determining the different positions of solder balls 22 of different sizes in the printed circuit board 21. Based on the positions of the solder balls 22 of different sizes in the printed circuit board 21, the position of the raised pressure head 31 on the second platform 30 is determined so that the solder balls 22 in the printed circuit board 21 can be flattened a second time to improve the yield of the printed circuit board 21.

[0025] In this embodiment, the solder balls 22 in the printed circuit board 21 are flattened a second time by means of the first platform 10 and the raised pressure head 31. During the second flattening of the printed circuit board 21, the smaller solder balls 22, which were flattened in the first flattening, need to be flattened again to increase their size, thereby reducing the size variation of the solder balls 22 on the printed circuit board 21. Therefore, during the secondary flattening of the solder balls 22 in the printed circuit board, the position of the raised pressure head 31 on the second platform 30 needs to be set. That is, the raised pressure head 31 on the second platform 30 needs to correspond to the smaller solder balls 22 in the printed circuit board 21. In other words, the raised pressure head 31 is set at different positions on the second platform 30 based on the solder balls 22 of different sizes in the multilayer printed circuit board 21. Thus, during the secondary flattening of the solder balls 22 in the printed circuit board 21, the raised pressure head 31 can be set to correspond to the smaller solder balls 22 in the printed circuit board 21. During lamination, the smaller solder balls 22 in the printed circuit board 21 can be flattened a second time to flatten the smaller solder balls 22 after the first flattening, thereby increasing the size of the corresponding solder balls 22 and effectively reducing the difference between the solder balls 22 in the printed circuit board 21. Obviously, this application can set corresponding protruding pressure heads 31 on the second platform 30 according to the distribution of solder balls 22 in different printed circuit boards 21, that is, the area corresponding to the protruding pressure heads 31 on the second platform 30.

[0026] In an optional embodiment, the raised pressure head 31 is positioned to correspond to the smaller solder balls 22 in the printed circuit board 21. That is, the larger solder balls 22 in the printed circuit board 21 correspond to the area outside the region where the raised pressure head 31 is located. In other words, during the secondary lamination of the printed circuit board 21, the region where the raised pressure head 31 is located corresponds to the smaller solder balls 22, while the region on the second platform 30 without the raised pressure head 31 corresponds to the larger solder balls 22 in the printed circuit board 21. Clearly, by providing the raised pressure head 31 on the second platform 30, a gap is formed between the region on the second platform 30 without the raised pressure head 31 and the first platform 10, to prevent the larger solder balls 22 in the printed circuit board 21 from being flattened during the secondary lamination of the solder balls 22 on the printed circuit board 21.

[0027] In the above embodiment, by placing the component 20 to be flattened on the first platform 10 and providing a raised pressure head 31 on the side end face of the second platform 30 facing the first platform 10, the component 20 to be flattened is flattened. The raised pressure head 31 is set at different positions on the second platform 30 based on solder balls 22 of different sizes in the multilayer printed circuit board 21. This allows the raised pressure head 31 to be set to correspond to the smaller solder balls 22 in the printed circuit board 21, so as to flatten the smaller solder balls 22 after the first flattening, thereby increasing the size of the corresponding solder balls 22 and effectively reducing the difference between the solder balls 22 in the printed circuit board 21.

[0028] In an optional embodiment, the distance between the edge of the raised pressure head 31 and the edge of the second platform 30 is the same as the distance between the small solder ball 22 and the edge of the second platform 30. That is, when the raised pressure head 31 is set on the second platform 30, it can be set according to the size of the solder ball 22 in the printed circuit board 21. Specifically, when the solder ball 22 on the printed circuit board 21 is flattened for the second time, the size of the solder ball 22 after the first flattening can be obtained first, and the position of the small solder ball 22 can be obtained. Based on the position of the small solder ball 22, the raised pressure head 31 is set on the second platform 30. When the printed circuit board 21 with solder balls 22 is placed on the first platform 10, the second platform 30 can be set to correspond to the first platform 10, so that the distance between the small solder balls 22 in the printed circuit board 21 and the edge of the second platform 30 can be the distance between the edge of the raised pressure head 31 and the edge of the second platform 30. That is, the distance between the perimeter of the area where the small solder balls 22 are located in the printed circuit board 21 and the perimeter of the printed circuit board 21 is the distance between the perimeter of the raised pressure head 31 and the perimeter of the second platform 30. Thus, the area where the small solder balls 22 are located can correspond to the area where the raised pressure head 31 is located, thereby completing the secondary flattening of the small solder balls 22.

[0029] In an optional embodiment, when a raised pressure head 31 is provided on the second platform 30, the size of the solder balls 22 in the printed circuit board 21 after the first flattening can be obtained first, and specifically the small-sized solder balls 22 and large-sized solder balls 22 in the printed circuit board 21 can be obtained, thereby obtaining the distance between the edge of the small-sized solder ball 22 and the edge of the second platform 30. Figure 2 As shown, along the first direction 41, i.e., the length direction of the printed circuit board 21, the distances between the edge of the small solder ball 22 and the edge of the printed circuit board 21 are A and B, respectively; that is, the distances between the edge of the small solder ball 22 and the edge of the second platform 30 are A and B. Correspondingly, along the first direction 41, the distances between the edge of the protruding pressure head 31 and the second platform 30 are A and B. Along the second direction 42, i.e., the width direction of the printed circuit board 21, the distances between the edge of the small solder ball 22 and the edge of the printed circuit board 21 are C and D, respectively; that is, the distances between the edge of the small solder ball 22 and the edge of the second platform 30 are C and D. Correspondingly, along the second direction 42, the distances between the edge of the protruding pressure head 31 and the second platform 30 are C and D.

[0030] In an optional embodiment, the projection of the raised pressure head 31 onto the second platform 30 can be any one of a rectangle, triangle, ring, or circle. Specifically, this can be expressed as the shape of the area where the small solder balls 22 are located in the printed circuit board 21 is the shape of the raised pressure head 31, that is, the projection of the raised pressure head 31 onto the second platform 30 can be the area where the small solder balls 22 are located in the printed circuit board 21 after the first flattening.

[0031] In an optional embodiment, the height of the raised pressure head 31 is half the size difference between the large-size solder ball 22 and the small-size solder ball 22. That is, after the solder balls 22 in the printed circuit board 21 are flattened for the first time, there will be large-size solder balls 22 and small-size solder balls 22. The height of the raised pressure head 31 is half the size difference between the large-size solder balls 22 and the small-size solder balls 22. Therefore, after the solder balls 22 in the printed circuit board 21 are flattened for the second time, the size difference between the small-size solder balls 22 and the large-size solder balls 22 in the printed circuit board 21 can be reduced. In other words, the small-size solder balls 22 in the circuit board can be flattened again, thereby effectively reducing the size difference of the solder balls 22 on the circuit board.

[0032] In this embodiment, since the height of the raised pressure head 31 is half the size difference between the large-size solder ball 22 and the small-size solder ball 22, that is, when the solder ball 22 on the printed circuit board 21 is flattened for the second time, the second platform 30 can abut against the large-size solder ball 22 on the printed circuit board 21. This ensures that the large-size solder ball 22 and the small-size solder ball 22 are consistent in size after the second flattening, thereby reducing the size difference of the solder ball 22 in the printed circuit board 21.

[0033] During the flattening of the printed circuit board 21, some solder balls 22 may be too large or too small due to soldering requirements at certain locations on the printed circuit board 21. Since some of these oversized or undersized solder balls do not need to be flattened again during the secondary flattening of the printed circuit board 21, when preparing the raised pressure head 31, some oversized solder balls 22 and some undersized solder balls 22 can be removed from the printed circuit board 21. That is, the largest and smallest solder balls 22 in the circuit board can be removed. The corresponding size difference between the large solder balls 22 after removing the largest solder balls 22 and the small solder balls 22 after removing the smallest solder balls 22 can be calculated, and half of the size difference can be used to obtain the height of the raised pressure head 31.

[0034] In an optional embodiment, to more accurately determine the height of the raised pressure head 31, multiple batches of printed circuit boards 21 can be flattened once to obtain the size of the solder balls 22 in multiple batches of printed circuit boards 21. The largest and smallest solder balls 22 in the printed circuit boards 21 are removed, and the size difference between the large solder balls 22 after removing the largest solder balls 22 and the small solder balls 22 after removing the smallest solder balls 22 in each batch is calculated. That is, the size difference is calculated for each batch of printed circuit boards 21. Based on the size difference of the solder balls 22 in each batch, the average size difference is obtained, and half of the average size difference is calculated to obtain the height of the raised pressure head 31, thereby more accurately producing the height of the raised pressure head 31.

[0035] In other embodiments, the raised pressure head 31 on the second platform 30 can be modularly configured. For example, the area occupied by small-sized solder balls 22 in the printed circuit board 21 is distributed in a dotted manner, so the raised pressure head 31 can be configured to correspond to the area occupied by the small-sized solder balls 22. The specific configuration can be set according to actual needs, and this application does not make specific limitations here.

[0036] In an optional embodiment, when a printed circuit board 21 with solder balls 22 is disposed on the first platform 10, the end face with the solder balls 22 is positioned facing the first platform 10, that is, the other end face of the printed circuit board 21 is positioned corresponding to the protruding pressure head 31. Accordingly, a solder resist layer (not shown) can be formed on the end face of the printed circuit board 21 facing away from the solder balls 22 to protect the printed circuit board 21. This is to prevent excessive pressure from the protruding pressure head 31 on the solder resist layer of the printed circuit board 21 during flattening, which could damage it. Therefore, the length of the edge of the protruding pressure head 31 can be no more than 4 mm, preferably no more than 3.7 mm, thereby reducing the pressure on the printed circuit board 21 at the edge of the protruding pressure head 31, which could lead to excessive pressure on the printed circuit board 21 and damage to a portion of the printed circuit board 21. That is, the length of the edge of the protruding pressure head 31 is no more than 3.7mm. When flattening the printed circuit board 21, this effectively avoids damage to the solder resist layer caused by the protruding pressure head 31. Figure 2 As shown, the edge lengths X and Y of the protruding pressure head 31 are no greater than 3.7 mm.

[0037] In an optional embodiment, the adjacent edge connection of the raised pressure head 31 is rounded. That is, if the pressure between the connection point of the raised pressure head 31 and the printed circuit board 21 is too large, it will cause excessive pressure at the edge of the raised pressure head 31, resulting in damage to a part of the printed circuit board 21.

[0038] This application also provides a printed circuit board 21, which is prepared by the flattening device of any of the above embodiments, and a plurality of solder balls 22 are provided on one end face of the printed circuit board 21, and ink (not shown) is provided on the other end face.

[0039] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A flattening device, characterized in that, For secondary flattening of solder balls on multilayer printed circuit boards, the flattening device includes: The first platform is used to place the parts to be flattened. The second platform is spaced apart from the first platform. A protruding pressure head is provided on the side of the second platform facing the first platform. The protruding pressure head works with the first platform to flatten the part to be flattened. The raised pressure head is positioned at different locations on the second platform based on solder balls of different sizes in the printed circuit board.

2. The flattening device according to claim 1, characterized in that, The distance between the edge of the protruding pressure head and the edge of the second platform is the same as the distance between the small-sized solder ball and the edge of the second platform.

3. The flattening device according to claim 1, characterized in that, The projection of the protruding pressure head onto the second platform can be any one of a rectangle, triangle, ring, or circle.

4. The flattening device according to claim 1, characterized in that, The height of the raised pressure head is half the size difference between the large-sized solder ball and the small-sized solder ball.

5. The flattening device according to claim 1, characterized in that, The adjacent edges of the protruding pressure head are rounded.

6. The flattening device according to claim 1, characterized in that, The length of the edge of the protruding pressure head is no more than 4mm.

7. The flattening device according to claim 1, characterized in that, The raised pressure head corresponds to the small-sized solder ball in the printed circuit board, and the large-sized solder ball corresponds to the area outside the raised pressure head on the second platform.

8. The flattening device according to claim 1, characterized in that, The plane in which the protruding pressure head faces the first platform is arranged parallel to the plane in which the first platform faces the protruding pressure head.

9. A printed circuit board, characterized in that, The printed circuit board is manufactured by the flattening device as described in any one of claims 1-8.

10. The printed circuit board according to claim 9, characterized in that, The printed circuit board has several solder balls arranged on one side and ink formed on the other side.

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