Mechanical blind hole plate capable of improving press warping

Abstract

This utility model relates to a mechanical blind hole plate that can improve warping during lamination, comprising a central plate assembly, and an upper plate assembly and a lower plate assembly respectively stacked on opposite surfaces of the central plate assembly. The upper plate assembly includes a first copper foil layer, a first prepreg layer, a second copper foil layer, a board material layer, a second prepreg layer, and a third copper foil layer stacked sequentially, with the third copper foil layer stacked on the upper surface of the central plate assembly. The structure and thickness distribution of the lower plate assembly are mirror-symmetrical with those of the upper plate assembly. Because the structure and thickness distribution of the lower plate assembly are mirror-symmetrical with those of the upper plate assembly, this symmetrical structure can effectively balance the stress distribution of the entire plate during lamination. During lamination, the pressure on various parts of the plate can be more evenly offset, thereby significantly reducing the possibility of warping of the entire plate due to uneven stress.

Description

Technical Field

[0001] This utility model relates to the field of circuit boards, and more specifically, to a mechanical blind hole board that can improve the warpage caused by lamination. Background Technology

[0002] In the electronics manufacturing industry, circuit boards, as the supporting carriers for electronic components, directly affect the reliability of electronic products due to their flatness and dimensional stability. In related technologies, mechanically operated blind via boards are prone to warping after pressing. Cross-sectional analysis reveals that this warping is caused by the asymmetrical structure of the blind via layer in existing blind via boards. Figure 1 As shown, the structure of the blind via layer is usually achieved by laminating copper foil onto copper-clad laminate material using PP. This can lead to asymmetric stress after lamination, with the copper-clad laminate layer experiencing less stress shrinkage while the copper foil and PP layers experience greater stress shrinkage. This causes the laminate to warp towards the copper foil surface after lamination, affecting the quality of the produced board. Subsequent processing can easily result in problems such as damaged boards during forming and cutting, misaligned drilling holes, and board jamming and scrapping in the grinding machine. Utility Model Content

[0003] In view of this, the present invention provides a mechanical blind hole plate that can improve the warping of the press.

[0004] The objective of this utility model is achieved through the following technical solution:

[0005] A mechanical blind hole plate that can improve press-fit warpage includes a central plate assembly, and an upper plate assembly and a lower plate assembly respectively stacked on two opposite surfaces of the central plate assembly; the upper plate assembly includes a first copper foil layer, a first prepreg layer, a second copper foil layer, a board material layer, a second prepreg layer, and a third copper foil layer stacked sequentially, the third copper foil layer being stacked on the upper surface of the central plate assembly; the structure and thickness distribution of the lower plate assembly are mirror-symmetrical to those of the upper plate assembly.

[0006] In the above technical solution, the stacking order of the layers in the upper plate assembly plays a crucial role. The first, second, and third copper foil layers have good ductility and conductivity. The first and second prepreg layers can fill the gaps and bond the materials during the lamination process, while the plate layer provides a certain strength foundation for the entire structure. This multi-layer material combination allows the layers to restrain each other during the lamination process, preventing any layer from deforming excessively due to excessive stress, thereby improving the warping phenomenon of the upper plate during lamination.

[0007] Furthermore, because the lower plate assembly's structure and thickness distribution are mirror-symmetrical to the upper plate assembly, this symmetrical structure effectively balances the stress distribution throughout the plate during the pressing process. During pressing, the pressure on each part of the plate can be relatively evenly offset, thus significantly reducing the possibility of warping due to uneven stress.

[0008] Optionally, in one possible implementation, the center plate assembly includes a substrate layer, and a first bonding layer and a second bonding layer stacked on two opposite surfaces of the substrate layer. The upper plate assembly is press-fitted to the upper surface of the substrate through the first bonding layer, and the lower plate assembly is press-fitted to the lower surface of the substrate through the second bonding layer.

[0009] In the above technical solution, the first and second bonding layers in the central plate assembly are used to connect the upper and lower plate assemblies, respectively. This double-layer bonding design enhances the overall stability of the plate connection. The first and second bonding layers also play a role in stress dispersion within the entire plate structure. When the plate is affected by external pressure or temperature changes, stress is transferred between the layers, further reducing stress concentration.

[0010] Optionally, in one possible implementation, the first bonding layer and the second bonding layer have the same structure, both including one or two third semi-cured sheets.

[0011] In the above technical solution, the identical structure of the first bonding layer and the second bonding layer further enhances the symmetry of the entire board structure. During the pressing process, the bonding layers with the same structure can make the stress distribution in the upper and lower directions more uniform. Furthermore, the identical application of the third semi-cured sheet layer in the first bonding layer and the second bonding layer can ensure the uniform bonding performance of the entire board.

[0012] Optionally, in one possible implementation, the first bonding layer and the second bonding layer have the same structure, both including a third prepreg layer disposed on the side of the third copper foil layer facing the substrate layer, and a fourth prepreg layer disposed on the side of the third prepreg layer facing the substrate layer and connected to the upper or lower surface of the substrate layer.

[0013] In the above technical solution, the multi-layer bonding structure provides stronger adhesion. The third and fourth prepreg layers work together to bond to adjacent layers from different levels. For example, the third prepreg layer first has good adhesion to the third copper foil layer, while the fourth prepreg layer bonds to the surface of the substrate layer. They complement each other, making the connection between the upper or lower board assembly and the substrate layer more secure.

[0014] Optionally, in one possible implementation, the central plate assembly includes a plurality of third semi-cured layers, fourth semi-cured layers, and fifth semi-cured layers stacked together.

[0015] In the above technical solution, the third, fourth, and fifth pre-cured layers undergo a curing reaction during the pressing process, tightly bonding each layer together. This provides more comprehensive interlayer adhesion, enabling it to better withstand external pressure, tension, and other mechanical forces, reducing the possibility of deformation or damage during use.

[0016] Optionally, in one possible implementation, both the upper plate group and the lower plate group are provided with a plurality of through holes.

[0017] In the above technical solution, the vias on the upper and lower boards will form corresponding blind vias after the entire board is laminated, which can provide more diverse paths for signal transmission and realize conduction between different layers.

[0018] Alternatively, in one possible implementation, the thickness of the first copper foil layer is the same as the thickness of the third copper foil layer, and is half the thickness of the second copper foil layer.

[0019] In the above technical solution, copper foil layers of different thicknesses can adjust signal transmission characteristics. The first and third copper foil layers are relatively thin, while the second copper foil layer is relatively thick. This thickness difference can be used to control signal transmission speed, attenuation, etc. Furthermore, since the second copper foil layer is a board-grade copper layer, and the first and third copper foil layers are supported by the first and second prepreg layers respectively, the thickness can be reduced to save costs.

[0020] Optionally, in one possible implementation, the substrate layer is any one of a metal plate, a resin plate, or a high-frequency plate.

[0021] In the above technical solutions, different substrates have different properties, and the design of multiple substrates can adapt to a variety of different performance requirements. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model.

[0024] Figure 2 This is a structural schematic diagram of Embodiment 2 of the present invention.

[0025] Figure 3 This is a structural schematic diagram of Embodiment 3 of the present invention.

[0026] Reference numerals: 1-Central board assembly; 11-Substrate layer; 121-Third prepreg layer; 122-Fourth prepreg layer; 123-Fifth prepreg layer; 2-Upper board assembly; 21-First copper foil layer; 22-First prepreg layer; 23-Second copper foil layer; 24-Board material layer; 25-Second prepreg layer; 26-Third copper foil layer; 3-Lower board assembly. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. Example

[0029] Please refer to Figure 1 This embodiment provides a mechanical blind hole plate that can improve press-fit warpage, including a central plate assembly 1, and an upper plate assembly 2 and a lower plate assembly 3 respectively stacked on opposite surfaces of the central plate assembly 1; the upper plate assembly 2 includes a first copper foil layer 21, a first prepreg layer 22, a second copper foil layer 23, a board material layer 24, a second prepreg layer 25, and a third copper foil layer 26 stacked sequentially, with the third copper foil layer 26 stacked on the upper surface of the central plate assembly 1; the structure and thickness distribution of the lower plate assembly 3 are mirror-symmetrical to those of the upper plate assembly 2. Specifically, the upper plate assembly 2 and the lower plate assembly 3 have mirror-symmetrical stacked structures, and the layers of the upper plate assembly 2 are formed by pressing, and the upper plate assembly 2, the central plate assembly 1, and the lower plate assembly 3 are also formed by pressing.

[0030] The stacking order of the layers in the upper plate assembly 2 plays a crucial role. The first copper foil layer 21, the second copper foil layer 23, and the third copper foil layer 26 have good ductility and conductivity. The first semi-cured sheet layer 22 and the second semi-cured sheet layer 25 can fill the gaps and bond the materials in each layer during the lamination process. The plate layer 24 provides a certain strength foundation for the entire structure. This multi-layer material combination allows the layers to restrain each other during the lamination process, preventing any layer from deforming excessively due to excessive stress, thereby improving the warping phenomenon of the upper plate during lamination.

[0031] Furthermore, since the structure and thickness distribution of the lower plate group 3 are mirror images of the upper plate group 2, this symmetrical structure can effectively balance the stress distribution of the entire plate during the pressing process. During pressing, the pressure on each part of the plate can be relatively evenly canceled out, thereby significantly reducing the possibility of warping of the entire plate due to uneven stress. For example, when pressure is applied from one side, the other side of the symmetrical structure can provide a reverse supporting force, keeping the plate flat as a whole.

[0032] It should be noted that the second copper foil layer 23 and the board layer 24 in this embodiment are board copper structures, that is, when the product is delivered, each surface of the board is already covered with a layer of copper foil. At this time, only the copper foil on one surface needs to be retained as the second copper foil layer 23, and the remaining copper foil needs to be etched away.

[0033] In this embodiment, the central plate assembly 1 includes a substrate layer 11, and a first bonding layer and a second bonding layer stacked on opposite surfaces of the substrate layer 11. The upper plate assembly 2 is pressed and connected to the upper surface of the substrate through the first bonding layer, and the lower plate assembly 3 is pressed and connected to the lower surface of the substrate through the second bonding layer. During the pressing process, the first bonding layer and the second bonding layer can simultaneously provide adhesive force from both the upper and lower surfaces of the substrate layer 11, firmly fixing the upper plate assembly 2 and the lower plate assembly 3 to the substrate layer 11.

[0034] The first and second bonding layers in the central plate assembly 1 are used to connect the upper plate assembly 2 and the lower plate assembly 3, respectively. This double-layer bonding design enhances the overall stability of the plate connection. The first and second bonding layers also play a role in stress dispersion within the entire plate structure. When the plate is affected by external pressure or temperature changes, stress is transferred between the layers, further reducing stress concentration. Furthermore, the presence of the first and second bonding layers provides greater flexibility in material selection for the central plate assembly 1. Different types of bonding layer materials can be selected according to different application requirements.

[0035] In this embodiment, the first bonding layer and the second bonding layer have the same structure, both including one or two third semi-cured sheet layers 121.

[0036] The identical structure of the first and second bonding layers further enhances the symmetry of the overall board structure. During the pressing process, the bonding layers with the same structure can make the stress distribution in both the upper and lower directions more uniform. Furthermore, the identical application of the third semi-cured sheet 121 in the first and second bonding layers ensures that the bonding performance of the entire board is uniform.

[0037] It should be noted that the first, second, and third prepregs in this embodiment are all P-sheets. P-sheets are prepreg materials composed of resin (such as epoxy resin) and reinforcing materials (such as fiberglass cloth). When uncured, P-sheets are tacky, facilitating lamination. During the pressing process (typically at 150-200°C and 10-30 kg / cm²), the resin flows and fills the gaps, forming a strong bond. P-sheets can be categorized by thickness into many different types, such as the thin 106 type, the medium-thickness 1080 type, the thicker 2116 type, and the extremely thick 7628 type, among many others that are not listed here.

[0038] In this embodiment, the first prepreg is a 3313 type P-sheet, the second prepreg is a 106 type P-sheet, and the third prepreg is a 1080 type P-sheet.

[0039] In this embodiment, both the upper plate group 2 and the lower plate group 3 are provided with a number of vias. After the entire plate is laminated, the vias on the upper plate group 2 and the lower plate group 3 will form corresponding blind holes, which can provide more diverse paths for signal transmission and realize conduction between different layers.

[0040] It should be noted that the thickness of the first copper foil layer 21 is the same as the thickness of the third copper foil layer 26, and is half the thickness of the second copper foil layer 23. Specifically, in this embodiment, the thickness of the first copper foil layer 21 and the third copper foil layer 26 is HOZ (half an ounce), and the thickness of the second copper foil layer 23 is 1 oz (1 ounce).

[0041] Different thicknesses of copper foil layers can adjust signal transmission characteristics. The first copper foil layer 21 and the third copper foil layer 26 are relatively thin, while the second copper foil layer 23 is relatively thick. This thickness difference can be used to control signal transmission speed, attenuation, etc. Meanwhile, since the second copper foil layer 23 is a board copper layer, and the first copper foil layer 21 and the third copper foil layer 26 are supported by the first prepreg layer 22 and the second prepreg layer 25 respectively, the thickness can be reduced to save costs.

[0042] Furthermore, in this embodiment, the substrate layer 11 can be any one of a metal plate, a resin plate, or a high-frequency plate. Different substrates have different properties, and the design of multiple substrates can adapt to a variety of different performance requirements. Example

[0043] Please refer to Figure 2The difference between this embodiment and Embodiment 1 lies in the structure of the first bonding layer and the second bonding layer in the central board assembly 1. In this embodiment, the first and second bonding layers have the same structure, both including a third prepreg layer 121 disposed on the side of the third copper foil layer 26 facing the substrate layer 11, and a fourth prepreg layer 122 disposed on the side of the third prepreg layer 121 facing the substrate layer 11 and connected to the upper or lower surface of the substrate layer 11. Specifically, different types of third prepreg layers 121 and fourth prepreg layers 122 are used to jointly constitute the first or second bonding layer. The third prepreg uses a 1080 type P-sheet, and the fourth prepreg uses a 2116 type P-sheet.

[0044] The multi-layer bonding structure provides stronger adhesion. The third prepreg layer 121 and the fourth prepreg layer 122 work together to bond to adjacent layers from different levels. For example, the third prepreg layer 121 first bonds well to the third copper foil layer 26, while the fourth prepreg layer 122 bonds to the surface of the substrate layer 11. They complement each other, making the connection between the upper board assembly 2 or the lower board assembly 3 and the substrate layer 11 more robust. Furthermore, the arrangement of the third prepreg layer 121 and the fourth prepreg layer 122 can better adapt to the bonding requirements between different materials. In addition, the 1080 type P-sheet has a high adhesive content, which can better fill the blind holes on the upper board assembly 2 and the lower board assembly 3.

[0045] It should be noted that the first and second bonding layers in this embodiment are mirror images. Since the first and second bonding layers have identical structures, this symmetrical structure offers unique advantages in stress buffering. Under stress, the symmetrical bonding layers can balance the stress distribution, resulting in a more uniform stress distribution across the entire plate in the vertical direction. Example

[0046] Please refer to Figure 3 The difference between this embodiment and Embodiments 1 and 2 is that the central plate assembly 1 is composed of prepreg sheets, i.e., without a base plate support. Specifically, the central plate assembly 1 includes several stacked third prepreg layers 121, fourth prepreg layers 122, and fifth prepreg layers 123. In this embodiment, the central plate assembly 1 is configured with six layers, stacked in the order of third prepreg layer 121, fourth prepreg layer 122, fifth prepreg layer 123, fifth prepreg layer 123, fourth prepreg layer 122, and third prepreg layer 121, so that the central plate assembly 1 itself also has a mirror structure. The third prepreg is a 1080 type P-sheet, the fourth prepreg is a 2116 type P-sheet, and the fifth prepreg is a 7628 type P-sheet.

[0047] In this embodiment, the third semi-cured layer 121, the fourth semi-cured layer 122, and the fifth semi-cured layer 124 undergo a curing reaction during the pressing process, tightly bonding each layer together. This provides more comprehensive interlayer adhesion, enabling it to better withstand external pressure, tension, and other mechanical forces, reducing the possibility of deformation or damage during use.

[0048] In the description of this utility model, it should be understood that terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0050] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mechanical blind hole plate that can improve press-fit warpage, characterized in that, The system includes a central plate assembly, and an upper plate assembly and a lower plate assembly respectively stacked on two opposite surfaces of the central plate assembly. The upper plate assembly includes a first copper foil layer, a first prepreg layer, a second copper foil layer, a board material layer, a second prepreg layer, and a third copper foil layer stacked sequentially, with the third copper foil layer stacked on the upper surface of the central plate assembly. The structure and thickness distribution of the lower plate assembly are mirror-symmetrical to those of the upper plate assembly.

2. The mechanical blind hole plate according to claim 1, which can improve press-fit warpage, is characterized in that, The central plate assembly includes a substrate layer, and a first bonding layer and a second bonding layer stacked on two opposite surfaces of the substrate layer. The upper plate assembly is pressed and connected to the upper surface of the substrate through the first bonding layer, and the lower plate assembly is pressed and connected to the lower surface of the substrate through the second bonding layer.

3. The mechanical blind hole plate according to claim 2, which can improve press-fit warpage, is characterized in that, The first bonding layer and the second bonding layer have the same structure, both including one or two third semi-cured film layers.

4. The mechanical blind hole plate according to claim 2, which can improve press-fit warpage, is characterized in that, The first bonding layer and the second bonding layer have the same structure, both including a third prepreg layer disposed on the side of the third copper foil layer facing the substrate layer, and a fourth prepreg layer disposed on the side of the third prepreg layer facing the substrate layer and connected to the upper or lower surface of the substrate layer.

5. The mechanical blind hole plate according to claim 1, which can improve press-fit warpage, is characterized in that, The central plate assembly includes several third semi-cured layers, fourth semi-cured layers, and fifth semi-cured layers stacked together.

6. The mechanical blind hole plate according to claim 1, which can improve press-fit warpage, is characterized in that, Both the upper plate assembly and the lower plate assembly are provided with several through holes.

7. The mechanical blind hole plate according to claim 1, which can improve press-fit warpage, is characterized in that, The thickness of the first copper foil layer is the same as the thickness of the third copper foil layer, and is half the thickness of the second copper foil layer.

8. The mechanical blind hole plate according to claim 2, which can improve press-fit warpage, is characterized in that, The substrate layer can be any one of a metal plate, a resin plate, or a high-frequency plate.

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