PCB with uniform thickness

Abstract

The utility model discloses a PCB with uniform thickness, the PCB comprises two outer-layer boards and a plurality of inner-layer boards, the outer-layer boards of the PCB are shielding copper layers, and the inner-layer boards of the PCB are provided with fusion block areas; in the inner layer board on the outermost layer of the PCB, the fusion block area is a base material, and in other inner layer boards of the PCB, the fusion block area comprises a fusion block and a plurality of glue points which are arranged on the base material. Compared with the PCB in the prior art, the fusion block and the glue point in the fusion block area of the inner-layer board at the outermost layer are removed, that is, the thickness of the fusion block area of the whole PCB is reduced, so that when the PCB is fused, the fusion block area can be smoother, the thickness difference between the fusion block area and the non-fusion block area is reduced, and the fusion efficiency of the PCB is improved. Therefore, the occurrence rate of burrs generated by the crimping hole near the fusion block area can be greatly reduced, the post-processing procedure of the burrs is reduced, and the production efficiency and quality of the PCB are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to circuit board manufacturing technical field especially relates to a thickness even's PCB. BACKGROUND

[0002] PCB (Printed Circuit Board), Chinese name is printed circuit board, is the support body of electronic components, and the PCB is composed of multiple layers of conductive and insulating materials, which are stacked and connected through a precise manufacturing process. The fusion of the PCB board refers to the process of bonding multiple inner layer core boards together through high temperature and high pressure to form a multi-layer PCB board.

[0003] The hot melt glue in the hot melt block area of the PCB is in a molten state when hot melting, but due to the poor flowability of the hot melt block during pressing, the glue points at both ends of the hot melt block flow, resulting in a height difference in the thickness of the board edge, so that the thickness of the fusion block area is thicker than other non-fusion block areas, and the pressure connection hole is adjacent to the fusion block, so the pressure connection hole area is relatively thin compared to the fusion block area. After pressing, the unit pressure connection hole area is prone to burr and burr, which seriously affects the product quality and process stability, and even affects the use safety and stability of the final product. Therefore, after the burr is generated, a burr and burr post-processing process needs to be added, mainly through manual brushing with a brush, but manual deburring is time-consuming and laborious and the quality cannot be guaranteed.

[0004] Due to the small improvement space of the process method, it is necessary to improve the design structure of the fusion block to improve the thickness difference of the board to avoid the problem of burr and burr in the unit pressure connection hole area after fusion. INVENTION CONTENTS

[0005] The utility model provides a kind of thickness even's PCB to solve the problem of burr and burr in unit pressure connection hole area due to the thickness difference of board.

[0006] The utility model provides a kind of thickness even's PCB, the PCB includes two outer layers and multiple inner layers, the outer layer of the PCB is shielding copper layer, and the inner layer of the PCB is provided with fusion block area;

[0007] In the outermost inner layer of the PCB, the fusion block area is base material:

[0008] In other inner layers of the PCB, the fusion block area includes fusion block and multiple glue points arranged on the base material:

[0009] Optionally, in other inner layers of the PCB, a groove is formed in the middle position of the length direction of the fusion block.

[0010] Optionally, the width of the groove is 0.2mm.

[0011] Optionally, the material of the fusion block and the glue point is copper.

[0012] Optionally, the length of the fusion block is 19mm, and the width is 5mm.

[0013] Optionally, the fusion block is in a grid shape, the width of the line segment between two adjacent grid openings is 1mm, and the distance between two adjacent line segments is 1mm.

[0014] Optionally, the glue point is circular.

[0015] Optionally, the diameter of the glue point is 1mm, and the center distance between two adjacent glue points is 3mm.

[0016] Optionally, the PCB includes a crimping hole, the fusion block area is square, in the long side of the fusion block area, one side close to the edge of the PCB is a first side, and one side away from the edge of the PCB is a second side, the second side is adjacent to the crimping hole.

[0017] Optionally, the short side of the fusion block area and the first side are adjacent to a glue blocking line, the distance between the short side of the fusion block area and the glue blocking line is 4mm, and the distance between the first side and the glue blocking line is between 8mm and 10mm.

[0018] The PCB with uniform thickness provided by the embodiment of the present application includes two outer plates and a plurality of inner plates, the outer plate of the PCB is a shielding copper layer, and the inner plate of the PCB is provided with a fusion block area; in the outermost inner plate of the PCB, the fusion block area is a base material; in other inner plates of the PCB, the fusion block area includes a fusion block and a plurality of glue points arranged on the base material. Compared with the PCB in the prior art, the fusion block and the glue point in the fusion block area of the outermost inner plate are removed, that is, the thickness of the fusion block area of the entire PCB is reduced, so that the thickness difference between the fusion block area and the non-fusion block area can be reduced during the fusion of the PCB, and the occurrence rate of burrs of the crimping hole near the fusion block area can be greatly reduced, the post-processing process of the burrs is also reduced, and the PCB production efficiency and quality are improved.

[0019] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to make the technical scheme in the embodiments of the present application clearer, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0021] Figure 1 is a partial structure diagram of an inner layer board in a PCB in the prior art provided by the present application;

[0022] Figure 2 is a partial structure diagram of an outermost inner layer board in a PCB provided by the embodiments of the present application;

[0023] Figure 3 is a partial structure diagram of other inner layer boards in a PCB provided by the embodiments of the present application;

[0024] Figure 4 is a partial structure diagram of other inner layer boards in a PCB provided by another embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the technical scheme in the embodiments of the present application clearer, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0026] In order to clearly illustrate the difference between the PCB structure of the present application and the PCB structure of the prior art and the technical effects brought by the difference, the following will combine the drawings of the embodiments of the present application to make a detailed description. Figure 1 The PCB structure in the prior art is described as follows, Figure 1 is a partial structure diagram of an inner layer board in a PCB in the prior art, as shown in Figure 1 In the inner layer board of the PCB in the prior art, each inner layer board includes a fusion block area 1 (the part enclosed by the dashed line in Figure 1 ) and a glue blocking area 2, the glue blocking area 2 is used to limit the flow range of the hot melt glue in the fusion block area 1, the fusion block area 1 includes a fusion block 11 and a plurality of glue points 12, the height of the fusion block 11 and the glue points 12 is usually the same, and the glue points 12 are used to balance the thickness of the board. The fusion block area 1 is adjacent to a pressing hole (in Figure 1The multi-layer inner layer plate is laminated and pressed under high temperature and high pressure during fusion, specifically, the fusion is achieved by a hot melting machine under the action of high temperature and pressure to bond and fix the prepreg and the core plate, so as to ensure the alignment accuracy of different layers and avoid interlayer slippage during subsequent processing. The position of the hot melting block area 1 is also aligned and laminated when the plurality of inner layer plates are laminated. The hot melting block 11 is in a molten state during hot melting, and the hot melting glue at the position of the hot melting block has poor flowability during pressing, so that the thickness of the hot melting block 11 is relatively high. In general, the thickness of the fusion block area 1 is 0.2-0.5mm thicker than that of other non-fusion block areas. At this time, the high temperature and high pressure fusion of the multi-layer inner layer plate will cause the crimping hole in the non-fusion block area with relatively thin thickness to bear a large force and generate burrs.

[0027] In order to solve the problem of uneven thickness of the fusion block area and the non-fusion block area in the prior art, in an embodiment of the present application, a PCB with uniform thickness is provided, the PCB comprises two outer layer plates and a plurality of inner layer plates, and the outer layer plate of the PCB is a shielding copper layer. The outer layer plate is the outermost layer of the PCB and directly contacts with the external environment, and is composed of a conductive layer and an insulating layer, but the conductive path on the outer layer plate is usually formed by silk screen printing, photoetching or directly depositing conductive material on the insulating substrate. The inner layer plate is located inside the multi-layer structure of the PCB and is not directly exposed to the outside. Generally, the PCB is a multi-layer plate structure, for example, the number of layers can be between 18-30 layers, or other numbers.

[0028] Figure 2 A partial structure diagram of the inner layer plate of the outermost layer in the PCB provided by the present application is shown in Figure 2 As shown in the figure, the inner layer plate of the PCB is provided with a fusion block area 3 Figure 2 (enclosed by the dashed line), in the inner layer plate of the outermost layer of the PCB, the fusion block area 3 is a substrate 5, which is the base material of the inner layer plate. The number of the inner layer plate of the outermost layer is 2 layers.

[0029] Figure 3 A partial structure diagram of other inner layer plates in the PCB provided by the present application is shown in Figure 3 As shown in the figure, the inner layer plate of the PCB is provided with a fusion block area 3 Figure 3 (enclosed by the dashed line), in the other inner layer plates of the PCB, the fusion block area 3 comprises a fusion block 31 and a plurality of glue points 32 arranged on the substrate, and the heights of the fusion block 31 and the glue points 32 are usually the same. The other inner layer plates are all the inner layer plates in the PCB except the inner layer plate of the outermost layer.

[0030] The fusion block area 3 is adjacent to the crimping hole (in Figure 2 and Figure 3not shown).

[0031] For the inner layer of the PCB, it usually includes a core board (CORE) and a prepreg, the core board is the basic material constituting the printed board, which is a hard plate with a certain thickness, and the two sides are wrapped with copper foil as a conductive layer. The main function of the core board is to provide support and conductive path for the circuit, so different core boards and prepregs need to be bonded, so there are usually fusion blocks 31 and multiple glue points 32 in the fusion block area 3 of each inner layer. But in the utility model, considering that the outer layer of the PCB is not a core board but a shielding copper layer, the inner layer and the outer layer of the outermost layer do not need to be bonded by fusion blocks 31 and glue points 32, so in the inner layer of the outermost layer, the fusion blocks 31 and the glue points 32 are removed, and the area of the substrate 5 in the fusion block area 3. For the entire PCB, the number of inner layers of the outermost layer is 2, so the thickness of 2 layers of fusion blocks 31 and glue points 32 is reduced, that is, the thickness of the fusion block area 3 in the entire PCB is reduced, that is, the thickness difference between the fusion block area 3 and the non-fusion block area is reduced, so that the thickness of the fusion block area 3 and the non-fusion block area of the PCB is uniform.

[0032] The thickness-uniform PCB provided by the embodiment of the utility model, the PCB includes two outer layers and multiple inner layers, the outer layer of the PCB is a shielding copper layer, and the inner layer of the PCB is provided with a fusion block area; in the inner layer of the outermost layer of the PCB, the fusion block area is a base material; in the other inner layers of the PCB, the fusion block area includes a fusion block and multiple glue points arranged on the base material. Compared with the PCB in the prior art, the fusion block and the glue point in the fusion block area of the inner layer of the outermost layer have been removed, that is, the thickness of the fusion block area of the entire PCB is reduced, so that when the PCB is fused, the thickness difference between the fusion block area and the non-fusion block area can be reduced, and then the occurrence rate of burrs of the crimping hole near the fusion block area can be greatly reduced, the post-processing process of the burrs is also reduced, and the production efficiency and quality of the PCB are improved.

[0033] In addition, in the embodiment, as shown in Figure 2 or Figure 3 each inner layer also includes a glue-blocking area 4, and the glue-blocking area 2 limits the flow range of the hot melt glue in the fusion block area 1.

[0034] In an optional embodiment, Figure 4This is a partial structural diagram of another inner layer board in a different PCB board. In this other inner layer board, a groove 33 is formed at the middle position along the length of the fusion block 31. By setting the groove 33, the stress caused by the fusion and pressing of the adhesive can be released, making the thickness of the fusion block region 3 more even. This avoids increasing the thickness of the fusion block region 3 due to unevenness in reducing its thickness, and thus reduces the thickness difference between the fusion block region 3 and the non-fusion block region. Specifically, the groove 33 can penetrate the fusion block 31, that is, the bottom of the groove 33 is the substrate 5.

[0035] In an optional embodiment, the width of the groove 33 is 0.2 mm.

[0036] In an optional embodiment, the fusion block 31 and the adhesive dots 32 are made of copper. Under high temperature and high pressure, the fusion block 31 and the adhesive dots 32 will melt into a gel and flow.

[0037] The size of the fusion block 31 can be set according to the size of the fusion region 3 and the size of the inner layer plate. In an optional embodiment, the length of the fusion block 31 is 19mm and the width is 5mm.

[0038] In an optional embodiment, the fusion block 31 is grid-shaped, with the width of the line segment between two adjacent grids being 1 mm and the distance between two adjacent line segments being 1 mm. The grid-shaped fusion block 31 can enhance the fluidity of the fusion block 32 under high temperature and high pressure, further improve the flatness of the fusion block 31, reduce the thickness of the fusion block region 3, and thus reduce the thickness difference between the fusion block region 3 and the non-fusion block region.

[0039] In an optional embodiment, the adhesive dots 32 are circular. Specifically, the diameter of the adhesive dots 32 is 1 mm, and the center-to-center distance between adjacent adhesive dots 32 is 3 mm.

[0040] In an optional embodiment, the PCB includes press-fit holes, such as... Figures 2-4 As shown, the fusion block area 3 is square. In the long side of the fusion block area 3, the side closer to the edge of the PCB is the first side, and the side farther away from the edge of the PCB is the second side. The second side is adjacent to the crimping hole.

[0041] In an optional embodiment, such as Figures 2-4 As shown, the short side of the fusion block region 3 and the first side are adjacent to the adhesive resistance line 4. The distance between the short side of the fusion block region 3 and the adhesive resistance line 4 is between 8mm and 10mm, and the distance between the first side and the adhesive resistance line 4 is 4mm. Specifically, the width of the adhesive resistance line 4 is greater than 1mm.

[0042] In general, the utility model reduces the plate thickness difference between the fusion block area and the non-fusion block area of the adjacent position from two aspects; on the one hand, the fusion block and the glue point in the inner layer plate structure of the outermost layer are removed, the thickness of the entire PCB fusion block area is reduced, that is, the plate thickness difference between the fusion block area and the non-fusion block area of the adjacent position can be reduced; on the other hand, grooves are arranged in other inner layer plates, stress caused by fusion and pressing and glue flow is released, the thickness of the fusion block area is more uniform, that is, the plate thickness difference between the fusion block area and the non-fusion block area of the adjacent position can be reduced.

[0043] It has been verified that the PCB structure of the utility model can solve the problem of the plate thickness difference between the fusion block area and the non-fusion block area of the adjacent position, and further solve the problem of drill hole burr caused by the problem, improve the product delivery yield and improve the production efficiency.

[0044] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, the steps described in the utility model can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions of the utility model can be achieved, which is not limited herein.

[0045] The above specific embodiment does not constitute a limitation on the protection scope of the utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A PCB of uniform thickness, characterized by, The PCB comprises two outer layers and multiple inner layers, the outer layers of the PCB are shielded copper layers, and the inner layers of the PCB are provided with fusion block regions; In the outermost inner layer of the PCB, the fusion block region is a base material: In other inner layers of the PCB, the fusion block region comprises fusion blocks and multiple glue points arranged on the base material.

2. The uniform thickness PCB of claim 1, wherein, In other inner layers of the PCB, a groove is arranged at the middle position of the length direction of the fusion block.

3. The uniform thickness PCB of claim 2, wherein, The width of the groove is 0.2 mm.

4. The uniform thickness PCB of claim 1, wherein, The material of the fusion block and the glue point is copper.

5. The uniform thickness PCB of claim 1, wherein, The length of the fusion block is 19 mm, and the width is 5 mm.

6. The uniform thickness PCB of claim 1, wherein, The fusion block is in a grid shape, the width of the line segment between two adjacent grid openings is 1 mm, and the distance between two adjacent line segments is 1 mm.

7. The uniform thickness PCB of any of claims 1-6, wherein, The glue point is circular.

8. The uniform thickness PCB of any of claims 1-6, wherein, The diameter of the glue point is 1 mm, and the center distance between adjacent glue points is 3 mm.

9. The uniform thickness PCB of any of claims 1-6, wherein, The PCB comprises a crimping hole, the fusion block region is square, in the long side of the fusion block region, one side close to the edge of the PCB is a first side, and the other side away from the edge of the PCB is a second side, the second side is adjacent to the crimping hole.

10. The uniform thickness PCB of claim 9, wherein, The short side of the fusion block region and the first side are adjacent to a glue blocking line, the distance between the short side of the fusion block region and the glue blocking line is between 8 mm and 10 mm, and the distance between the first side and the glue blocking line is 4 mm.

Images