Circuit board pressing structure

Abstract

The utility model discloses a circuit board pressing structure which comprises an inner layer plate assembly, a first copper foil, a second copper foil and a supporting plate. The inner-layer plate assembly comprises at least one inner-layer plate, prepregs are stacked on the two sides of each inner-layer plate, and the residual copper rate of the upper half portion of the inner-layer plate assembly is larger than the wire diameter of glass fiber cloth of the upper half portion of the inner-layer plate assembly and larger than the wire diameter of glass fiber cloth of the lower half portion of the inner-layer plate assembly. The first copper foil is stacked on the upper surface of the inner-layer plate assembly; and the second copper foil is stacked on the lower surface of the inner-layer plate assembly. The supporting plate is stacked on the upper side surface of the first copper foil. The copper-clad plate further comprises a connecting structure, and the supporting plate is detachably connected with the first copper foil and the inner-layer plate assembly through the connecting structure. In the structure, the supporting plate can play a role in supporting the inner-layer plate assembly in the high-temperature cooling process after hot pressing and prevent the inner-layer plate assembly from arching upwards and deforming, so that the manufacturing quality of the circuit board can be effectively improved, and the rejection rate of the circuit board can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit board production, in particular to a circuit board pressing structure. Background Art

[0002] Conventional circuit board designs typically feature a top-to-bottom symmetrical structure. Each layer of this type of board has the same structure and routing rules, ensuring that warpage of ≤0.75% is met during manufacturing, as specified by the IPC industry standard. However, to meet specific requirements, asymmetric circuit boards exist in the prior art. These boards typically have varying structures and routing rules between layers, leading to significant variations in residual copper content between inner layers, or between the two sides of a single inner layer. Furthermore, the type, quantity, or copper thickness of prepregs on either side of the inner layer can differ.

[0003] For asymmetric circuit boards, the internal stress release on both sides is inconsistent during the pressing process, which makes it easy for the board to bend or warp. Therefore, it is difficult to meet the IPC industry standard requirement of warpage ≤ 0.75%. When the board is severely warped, it is easy for the drilling holes to deviate, the outer layer circuit production exposure to be difficult to position, the solder mask exposure to be difficult to position, the exposure deviation to cause ink residue in the hole, and the peripheral molding size to be abnormal, which seriously affects the production quality of the circuit board and has a high scrap rate. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a circuit board pressing structure that can improve the manufacturing quality of the circuit board and reduce the scrap rate of the circuit board.

[0005] According to the circuit board pressing structure of the embodiment of the present invention, it includes: an inner layer board assembly, including at least one inner layer board, and semi-cured sheets are stacked on both sides of each inner layer board, the residual copper rate of the upper half of the inner layer board assembly is greater than the wire diameter of the glass fiber cloth in the upper half of the inner layer board assembly is greater than the wire diameter of the glass fiber cloth in the lower half of the inner layer board assembly; a first copper foil is stacked on the upper surface of the inner layer board assembly; a second copper foil is stacked on the lower surface of the inner layer board assembly; a support plate is stacked on the upper side surface of the first copper foil; wherein, it also includes a connecting structure, and the support plate is detachably connected to the first copper foil and the inner layer board assembly through the connecting structure.

[0006] The circuit board pressing structure according to the embodiment of the present utility model has at least the following beneficial effects:

[0007] By adopting the circuit board pressing structure of the embodiment of the present invention, since the side of the inner layer board assembly with a larger residual copper rate and / or a larger glass fiber wiring diameter is prone to upward arching and deformation due to the action of internal stress after hot pressing, the support plate is stacked on the side of the inner layer board assembly with a larger residual copper rate and / or a larger glass fiber wiring diameter, and the support plate is detachably connected to the first copper foil and the inner layer board assembly through a connecting structure. In this structure, since the support plate is not easily deformed after hot pressing, and the support plate is fixed to the inner layer board assembly, the support plate can prevent the inner layer board assembly from arching and deforming upward during the high-temperature cooling process after hot pressing. The support plate can be removed after the inner layer board assembly is completely cooled, thereby effectively improving the production quality of the circuit board and reducing the scrap rate of the circuit board.

[0008] According to some embodiments of the present invention, the support plate is an aluminum plate.

[0009] According to some embodiments of the present invention, the length of the support plate is smaller than the length of the inner plate assembly, and the width of the support plate is smaller than the width of the inner plate assembly.

[0010] According to some embodiments of the present invention, the connection structure is a rivet, and the support plate is detachably connected to the first copper foil and the inner layer assembly through the rivet.

[0011] According to some embodiments of the present invention, at least one rivet is detachably mounted on each side edge of the support plate.

[0012] According to some embodiments of the present invention, at least one fusion point is provided on the edge of the support plate, the support plate is fused and fixed to the first copper foil, and the first copper foil, the second copper foil and the inner layer board assembly are fused and fixed.

[0013] According to some embodiments of the present invention, at least one fusion point is provided on each side edge of the support plate.

[0014] According to some embodiments of the present invention, a kraft paper assembly is stacked on the upper surface of the support plate and the lower surface of the second copper foil, and the kraft paper assembly includes at least one piece of kraft paper.

[0015] According to some embodiments of the present invention, in the kraft paper assembly, the number of the kraft papers is at least two, all of which are stacked in sequence, at least one of which is new kraft paper, and at least one of which is old kraft paper.

[0016] According to some embodiments of the present invention, a steel plate is stacked on a side of each group of kraft paper components facing away from the inner layer board component.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 This is a partial schematic diagram of the circuit board pressing structure of an embodiment of the utility model;

[0020] Figure 2 A schematic diagram of a circuit board pressing structure according to an embodiment of the present utility model;

[0021] Figure 3 Schematic diagram of a circuit board according to an embodiment of the present invention.

[0022] Reference numerals:

[0023] Inner board assembly 100 , inner board 101 , prepreg 102 , first copper foil 110 , second copper foil 120 , support plate 130 , kraft paper assembly 140 , steel plate 150 , rivet 160 . DETAILED DESCRIPTION

[0024] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0025] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0026] In the description of this utility model, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0027] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0028] Reference Figures 1 to 3 One embodiment of the present invention provides a circuit board pressing structure, comprising an inner layer board assembly 100, a first copper foil 110, a second copper foil 120, and a support plate 130. The inner layer board assembly 100 comprises at least one inner layer board 101, with prepregs 102 stacked on both sides of each inner layer board 101. The residual copper rate of the upper half of the inner layer board assembly 100 is greater than the wire diameter of the glass fiber cloth in the upper half of the inner layer board assembly 100. The wire diameter of the glass fiber cloth in the lower half of the inner layer board assembly 100 is greater. The first copper foil 110 is stacked on the upper surface of the inner layer board assembly 100; the second copper foil 120 is stacked on the lower surface of the inner layer board assembly 100. The support plate 130 is stacked on the upper side surface of the first copper foil 110. It also includes a connecting structure, and the support plate 130 is detachably connected to the first copper foil 110 and the inner layer board assembly 100 through the connecting structure.

[0029] By adopting the circuit board pressing structure of the embodiment of the present invention, since the side of the inner layer board assembly 100 with a larger residual copper rate and / or a larger glass fiber wiring diameter is easily arched and deformed upward due to the action of internal stress and resin shrinkage deformation after hot pressing, the support plate 130 is stacked on the side of the inner layer board assembly 100 with a larger residual copper rate and / or a larger glass fiber wiring diameter, and the support plate 130 is detachably connected to the first copper foil 110 and the inner layer board assembly 100 through a connecting structure. In this structure, since the support plate 130 is not easily deformed after hot pressing, and the support plate 130 is fixed together with the inner layer board assembly 100, the support plate 130 can support the inner layer board assembly 100 during the high-temperature cooling process after hot pressing, thereby preventing the inner layer board assembly 100 from arching and deforming upward. The support plate 130 can be removed after the inner layer board assembly 100 is completely cooled, thereby effectively improving the production quality of the circuit board and reducing the scrap rate of the circuit board.

[0030] In addition, the support plate 130 removed during this process can also be used in the subsequent drilling process of the circuit board, thus achieving multiple uses.

[0031] It can be understood that, in the above structure, the prepreg 102 is mainly composed of resin and reinforcing material. In the embodiment of the present utility model, the prepreg 102 uses glass fiber cloth as the reinforcing material.

[0032] It can be understood that in the above structure, the second copper foil 120 can be directly stacked on the lower surface of the inner layer board assembly 100, or the second copper foil 120 can also be fixed together with the inner layer board assembly 100, the first copper foil 110, and the support plate 130 through a connecting structure. The present invention does not make specific limitations on this.

[0033] In some embodiments, the support plate 130 is an aluminum plate.

[0034] In the above structure, by setting the support plate 130 as an aluminum plate, it can not only support the inner layer plate assembly 100 during the high-temperature cooling process after hot pressing, but also prevent the inner layer plate assembly 100 from arching and deforming upward. In addition, during the plate pressing process, the aluminum plate can better transfer pressure to the inner layer plate 101, so that the pressure distribution between the copper-free area and the copper-containing area of ​​the inner layer plate 101 is more balanced and consistent, and the resin is evenly stressed and can fill the copper-free area of ​​the inner layer plate 101 to prevent the problem of insufficient glue filling. In addition, the aluminum plate also has good thermal conductivity, and can transfer heat to the inner layer plate assembly 100 well during the hot pressing process, which can be beneficial to the heat dissipation of the inner layer plate assembly 100 during the high-temperature cooling process after hot pressing.

[0035] Reference Figures 1 to 3 In some embodiments, the length of the support plate 130 is smaller than the length of the inner panel assembly 100 , and the width of the support plate 130 is smaller than the width of the inner panel assembly 100 .

[0036] In the above structure, by setting the size of the support plate 130 to be smaller than the size of the inner layer panel assembly 100, it is convenient to cut and grind the inner layer panel assembly 100 during the forming process after pressing the plate, avoiding interference between the support plate 130 and the forming tool during the forming process. Therefore, during forming, the support plate 130 can also be fixed together with the first copper foil 110 and the inner layer panel assembly 100, avoiding deformation of the inner layer panel assembly 100 due to internal stress during the forming process, and ensuring the integrity of the support plate 130 during the forming process, and the support plate 130 can be removed after forming.

[0037] In some embodiments, the size of the support plate 130 is 2 mm smaller on one side than the preset size of the inner layer plate assembly 100. The preset size of the inner layer plate assembly 100 specifically refers to the size of the inner layer plate assembly 100 after hot pressing and molding and film cutting. This can avoid the impact of molding tolerance on cutting during the molding process.

[0038] Reference Figures 1 to 3 In some embodiments, the connection structure is a rivet 160 , and the inner layer board assembly 100 , the first copper foil 110 and the support plate 130 are detachably connected via the rivet 160 .

[0039] In the above structure, by providing the connection structure as rivets 160, the structure is simple and easy to operate. Secondly, in the prior art, before the circuit board is pressed together, it is also necessary to rivet each inner layer board 101 and prepreg 102 of the circuit board. Therefore, in the embodiment of the utility model, the support plate 130 is riveted together with the first copper foil 110 and the inner layer board assembly 100 by rivets 160, which does not require additional process flow compared to the prior art.

[0040] Reference Figures 1 to 3 In some embodiments, three rivets 160 are detachably mounted on both edges of the support plate 130 in the length direction, and one rivet 160 is detachably mounted on both edges of the support plate 130 in the width direction.

[0041] By adopting the above structure, the connection stability between the support plate 130, the first copper foil 110 and the inner layer board assembly 100 can be further improved, and the supporting role of the support plate 130 on the inner layer board assembly 100 during the high-temperature cooling process after hot pressing can be improved, thereby better preventing the inner layer board assembly 100 from arching upward and deforming.

[0042] It is understood that the two edges of the support plate 130 in the length direction can be detachably mounted with three rivets 160, and the two edges of the support plate 130 in the width direction can be detachably mounted with one rivet 160. Figures 1 to 3 As an exemplary illustration, the present invention does not impose any specific limitation on the specific number of the rivets 160 , and it is sufficient that at least one rivet 160 is detachably mounted on each side edge of the support plate.

[0043] In some embodiments, at least one fusion point is provided at an edge of the support plate 130 , the support plate 130 is fused and fixed to the first copper foil 110 , and both the first copper foil 110 and the second copper foil 120 are fused and fixed to the inner layer board assembly 100 .

[0044] In the above structure, by fusing and fixing the support plate 130, the first copper foil 110, the inner layer board assembly 100, and the second copper foil 120, the support plate 130, the first copper foil 110, the inner layer board assembly 100, and the second copper foil 120 can be further positioned to prevent undesirable phenomena such as sliding plates from occurring during the hot pressing process.

[0045] It can be understood that the edge of the above-mentioned support plate 130 is provided with at least one fusion point, which means that during fusion fixing, the fusion machine can fuse the support plate 130 and the first copper foil 110 through a fusion point on the support plate 130, and fuse the first copper foil 110 and the second copper foil 120 to the inner layer board assembly 100.

[0046] In some embodiments, four fusion points may be evenly arranged on both edges of the support plate 130 in the length direction, and two fusion points may be evenly arranged on both edges of the support plate 130 in the width direction, thereby further preventing the occurrence of the sliding plate phenomenon.

[0047] It can be understood that the above-mentioned four fusion points are evenly set on the two edges in the length direction of the support plate 130, and two fusion points are evenly set on the two edges in the width direction of the support plate 130. This is merely an exemplary description of the present invention. The present invention does not make any specific restrictions on the specific number of fusion points. It is only required that at least one fusion point is set on each side edge of the support plate 130.

[0048] Reference Figure 2 In some embodiments, the upper surface of the support plate 130 and the lower surface of the second copper foil 120 are both stacked with a kraft paper assembly 140 , and the kraft paper assembly 140 includes at least one sheet of kraft paper.

[0049] In the above structure, the kraft paper can play a buffering role and balance the pressure during the hot pressing process, so that the inner layer panel assembly 100 is subjected to a more balanced force.

[0050] In some embodiments, in the kraft paper assembly 140 , there are eighteen sheets of kraft paper, all of which are stacked in sequence, twelve of which are new kraft paper and eight are old kraft paper.

[0051] In the above structure, by adopting a combination of twelve new kraft papers and eight old kraft papers, while ensuring the buffering effect and pressure balancing effect of the kraft paper assembly 140, part of the kraft paper can be recycled to save materials.

[0052] It can be understood that the number of the above-mentioned kraft papers is eighteen sheets, all of which are stacked in sequence, twelve of which are new kraft papers and eight are old kraft papers. This is merely an exemplary description of the present invention. The present invention does not specifically limit the number of kraft papers. It only requires that the number of kraft papers is at least two sheets, all of which are stacked in sequence, at least one of which is new kraft paper and at least one is old kraft paper.

[0053] Reference Figure 2 In some embodiments, a steel plate 150 is stacked on the side of each set of kraft paper components 140 facing away from the inner layer panel component 100 .

[0054] In the above structure, the steel plate 150 can effectively transfer the heat and pressure of the press to the inner plate assembly 100 and can also bear the load on the inner plate assembly 100 during the hot pressing process.

[0055] It is understandable that, in some embodiments, the sizes of the first copper foil 110 and the second copper foil 120 may be set to match the size of the steel plate 150 .

[0056] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. The circuit board pressing structure is characterized by: include: An inner panel assembly (100) comprises at least one inner panel (101), prepregs (102) being stacked on both sides of each inner panel (101), the residual copper rate of the upper half of the inner panel assembly (100) being greater than the residual copper rate of the lower half of the inner panel assembly (100), and / or the wire diameter of the glass fiber cloth of the upper half of the inner panel assembly (100) being greater than the wire diameter of the glass fiber cloth of the lower half of the inner panel assembly (100); A first copper foil (110) is stacked on the upper surface of the inner layer board assembly (100); A second copper foil (120) is stacked on the lower surface of the inner layer board assembly (100); A support plate (130) is stacked on the upper surface of the first copper foil (110); It also includes a connection structure, through which the support plate (130) is detachably connected to the first copper foil (110) and the inner layer board assembly (100).

2. The circuit board pressing structure according to claim 1, characterized in that: The support plate is an aluminum plate.

3. The circuit board pressing structure according to claim 2, characterized in that: The length of the support plate (130) is smaller than the length of the inner plate assembly (100), and the width of the support plate (130) is smaller than the width of the inner plate assembly (100).

4. The circuit board pressing structure according to claim 1, characterized in that: The connection structure is a rivet (160), and the support plate (130) is detachably connected to the first copper foil (110) and the inner layer component via the rivet (160).

5. The circuit board pressing structure according to claim 4, characterized in that: At least one rivet (160) is detachably mounted on each side edge of the support plate (130).

6. The circuit board pressing structure according to claim 4, characterized in that: At least one fusion point is provided on the edge of the support plate (130), the support plate (130) is fused and fixed to the first copper foil (110), and the first copper foil (110), the second copper foil (120) and the inner layer board assembly (100) are fused and fixed.

7. The circuit board pressing structure according to claim 6, characterized in that: Each side edge of the support plate (130) is provided with at least one fusion point.

8. The circuit board pressing structure according to claim 1, characterized in that: A kraft paper assembly (140) is stacked on the upper surface of the support plate (130) and the lower surface of the second copper foil (120), and the kraft paper assembly (140) includes at least one piece of kraft paper.

9. The circuit board pressing structure according to claim 8, characterized in that: In the kraft paper assembly (140), the number of the kraft papers is at least two, and all the kraft papers are stacked in sequence, wherein at least one of the kraft papers is new kraft paper, and at least one of the kraft papers is old kraft paper.

10. The circuit board pressing structure according to claim 8, characterized in that: A steel plate (150) is stacked on one side of each group of the kraft paper components (140) facing away from the inner layer plate component (100).

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