Copper clad plate preventing warping

Abstract

This utility model relates to an anti-warping copper-clad laminate in the field of copper-clad laminates, comprising a substrate, the surface of which is covered with a copper foil layer. The substrate is composed of three functional layers stacked together along the thickness direction, including a first stress-adjusting layer and a second stress-adjusting layer. The first stress-adjusting layer is a grid structure composed of continuously distributed rhombic units, and the second stress-adjusting layer is a honeycomb-shaped grid structure composed of multiple regular hexagonal through holes. The first stress-adjusting layer and the second stress-adjusting layer are arranged in an alternating symmetrical manner along the thickness direction of the substrate body. The connection points of the rhombic units of the first stress-adjusting layer and the midpoints of the edges of the regular hexagonal through holes of the second stress-adjusting layer form a vertical projection correspondence. The surfaces of the substrate layer, the first stress-adjusting layer, and the second stress-adjusting layer are coated with synthetic resin. The first stress-adjusting layer and the second stress-adjusting layer on both sides of the substrate layer form a complementary structure. The rhombic grid can resist transverse stress, and the honeycomb structure disperses longitudinal stress.

Description

Technical Field

[0001] This utility model relates to the field of copper clad laminates, and in particular to a copper clad laminate that prevents warping. Background Technology

[0002] Copper-clad laminate (CCL) is a core substrate in printed circuit board (PCB) manufacturing. It consists of an insulating substrate and a copper foil layer laminated to its surface, possessing both conductivity and insulation properties, and is widely used in electronic equipment. As electronic components become increasingly high-density and miniaturized, CCL requires excellent dimensional stability, heat resistance, and mechanical strength. Traditional CCL typically uses a hot-pressing process to bond the copper foil to a resin substrate; its performance directly determines the reliability and processing precision of the PCB.

[0003] Currently, most copper-clad laminates on the market use a single substrate layer or a simple multi-layer composite structure, such as epoxy resin substrate reinforced with fiberglass cloth, or fillers added to the substrate to adjust the coefficient of thermal expansion. During hot pressing or changes in ambient temperature and humidity, warping and deformation can easily occur due to the difference in the coefficient of thermal expansion between the substrate and the copper foil, as well as uneven internal stress distribution. Warping not only reduces the adhesion between the copper foil layer and the substrate, but also affects the accuracy of subsequent circuit etching and may even lead to poor component soldering. Utility Model Content

[0004] In order to overcome the shortcomings of existing technical solutions, this utility model provides a copper-clad laminate that is resistant to warping, which can effectively solve the technical problem of easy warping and deformation.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A warp-resistant copper-clad laminate includes a substrate with a copper foil layer covering its surface. The substrate is composed of three functional layers stacked together along its thickness direction, including a substrate layer located in the middle, a first stress-adjusting layer disposed on one side of the substrate layer, and a second stress-adjusting layer disposed on the side of the substrate layer away from the first stress-adjusting layer. The first stress-adjusting layer is a grid structure composed of continuously distributed rhombic units, and the second stress-adjusting layer is a honeycomb-shaped grid structure composed of multiple regular hexagonal through holes. The first stress-adjusting layer and the second stress-adjusting layer are arranged in an alternating symmetrical manner along the thickness direction of the substrate body. The connection points of the rhombic units of the first stress-adjusting layer and the midpoints of the edges of the regular hexagonal through holes of the second stress-adjusting layer form a vertical projection correspondence. The surfaces of the substrate layer, the first stress-adjusting layer, and the second stress-adjusting layer are wrapped with synthetic resin, and the copper foil layer is hot-pressed onto the surface of the synthetic resin.

[0007] Furthermore, the substrate layer is embedded with a grid-like frame structure formed by the interlacing of transverse and longitudinal reinforcing ribs. The intersection of the transverse and longitudinal reinforcing ribs forms an upwardly protruding hemispherical node. The node corresponds to the thickness of the first stress adjustment layer and the second stress adjustment layer. The hemispherical node can be paired and inserted into the grid of the first stress adjustment layer and the second stress adjustment layer.

[0008] Furthermore, the substrate layer is made of wood pulp paper, and the surface of the wood pulp paper is embossed to form hemispherical nodes.

[0009] Furthermore, the edge of the copper foil layer is provided with a chamfer that bends towards the substrate, the chamfer angle is 30-60°, and the end of the chamfer is embedded in the synthetic resin.

[0010] Furthermore, nano-silica particles are added to the synthetic resin, and the nano-silica particles are uniformly dispersed throughout the synthetic resin.

[0011] Furthermore, the rhomboid unit of the first stress adjustment layer has a side length of 0.8-1.5 mm and a grid line width of 0.1-0.3 mm, and the regular hexagonal through hole of the second stress adjustment layer has a side length of 0.5-0.8 mm and a hole wall thickness of 0.05-0.1 mm.

[0012] Compared with existing technologies, the beneficial effects of this invention are as follows: the first stress-adjusting layer and the second stress-adjusting layer on both sides of the substrate layer form a complementary structure. The rhombic grid can resist transverse stress, and the honeycomb structure disperses longitudinal stress. The two are symmetrically arranged through vertical projection to achieve dynamic cancellation of multi-directional stress, suppressing warping at its source. The vertical projection correspondence between the connection point of the rhombic unit and the midpoint of the edge of the hexagonal through-hole makes the stress transmission path inside the substrate form a three-dimensional mesh balance system, effectively avoiding deformation accumulation caused by local stress concentration. The complete encapsulation of the substrate layer and the stress-adjusting layer by the synthetic resin strengthens the interlayer bonding force. The pre-tightening force generated by the resin curing shrinkage further offsets the residual stress after hot pressing of the copper foil, improving the overall structural stability. Attached Figure Description

[0013] Figure 1 This is a structural diagram of the present invention;

[0014] Figure 2 This is a schematic diagram of the first stress-adjusting layer in this utility model;

[0015] Figure 3 This is a schematic diagram of the second stress-adjusting layer in this utility model;

[0016] Figure 4 This is a schematic diagram of the substrate layer in this utility model;

[0017] The numbers in the figure are: 1-copper foil layer, 2-first stress adjustment layer, 3-second stress adjustment layer, 4-substrate layer, 401-transverse reinforcing rib, 402-longitudinal reinforcing rib, 403-hemispherical node, 5-synthetic resin. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] The following is combined with Figures 1-4 A detailed description of an anti-warping copper-clad laminate according to this utility model is provided:

[0020] A warp-resistant copper-clad laminate includes a substrate with a copper foil layer 1 covering its surface. The substrate is composed of three functional layers stacked along its thickness direction, including a substrate layer 4 located in the middle, a first stress-adjusting layer 2 disposed on one side of the substrate layer 4, and a second stress-adjusting layer 3 disposed on the side of the substrate layer 4 away from the first stress-adjusting layer 2. The first stress-adjusting layer 2 is a grid structure composed of continuously distributed rhombic units, and the second stress-adjusting layer 3 is a honeycomb-shaped grid structure composed of multiple regular hexagonal through-holes. The first stress-adjusting layer 2 and the second stress-adjusting layer 3 are... 3. The components are arranged in an alternating symmetrical pattern along the thickness direction of the substrate body. The connection point of the rhombic unit of the first stress adjustment layer 2 and the midpoint of the edge of the regular hexagonal through hole of the second stress adjustment layer 3 form a vertical projection correspondence. The surfaces of the substrate layer 4, the first stress adjustment layer 2 and the second stress adjustment layer 3 are wrapped with synthetic resin 5. The copper foil layer 1 is hot-pressed onto the surface of the synthetic resin 5. The side length of the rhombic unit of the first stress adjustment layer 2 is 0.8 mm and the grid line width is 0.3 mm. The side length of the regular hexagonal through hole of the second stress adjustment layer 3 is 0.8 mm and the hole wall thickness is 0.1 mm.

[0021] The first stress-adjusting layer 2 and the second stress-adjusting layer 3 on both sides of the substrate layer 4 form a complementary structure. The rhomboid mesh resists transverse stress, and the honeycomb structure disperses longitudinal stress. The two are symmetrically arranged through vertical projection to achieve dynamic cancellation of multi-directional stress, suppressing warping at its source. The vertical projection correspondence between the connection points of the rhomboid units and the midpoints of the hexagonal through-hole edges creates a three-dimensional mesh-like balance system for stress transmission within the substrate, effectively avoiding deformation accumulation caused by local stress concentration. The synthetic resin 5 completely encapsulates the substrate layer 4 and the stress-adjusting layers, strengthening the interlayer bonding force. The pre-tightening force generated by the resin curing shrinkage further offsets the residual stress after hot pressing of the copper foil, improving the overall structural stability.

[0022] The substrate layer 4 is embedded with a grid-like frame structure formed by interlacing transverse reinforcing ribs 401 and longitudinal reinforcing ribs 402. At the intersection of the transverse and longitudinal reinforcing ribs 401 and 402, protruding hemispherical nodes 403 are formed. The thickness of these nodes corresponds to that of the first stress-adjusting layer 2 and the second stress-adjusting layer 3. The hemispherical nodes 403 can be paired and inserted into the grid of the first and second stress-adjusting layers 2 and 3. Through the grid-like frame structure formed by the transverse and longitudinal reinforcing ribs 402 embedded in the substrate layer 4, the bending strength of the substrate layer 4 is significantly improved. In particular, the hemispherical nodes 403 and the grids of the first and second stress-adjusting layers 3 form a paired interlocking structure, further enhancing the interlayer bonding force. This allows stress to be evenly transmitted along the grid path within the substrate layer 4, avoiding stress concentration in a single direction. Simultaneously, the protruding support of the nodes prevents the stress-adjusting layers from deforming under pressure, thereby synergistically improving the overall anti-warping performance.

[0023] The substrate layer 4 is made of wood pulp paper, and the surface of the wood pulp paper is embossed to form hemispherical nodes 403. The fiber structure of the wood pulp paper can absorb some of the thermal expansion stress. The hemispherical nodes 403 are directly formed by the embossing process, avoiding additional processing steps and ensuring that the size and position of the nodes are precisely matched with the mesh of the stress-adjusting layer, thus improving the interlayer structural fit. The flexibility of the wood pulp paper can also alleviate local stress abrupt changes during the curing process, further reducing the risk of warping.

[0024] The copper foil layer 1 has a chamfered edge that bends towards the substrate at an angle of 30°. The end of the chamfer is embedded in the synthetic resin 5, which effectively reduces the stress concentration at the interface between the copper foil and the substrate. After the end of the chamfer is embedded in the synthetic resin 5, it forms a hook to prevent the copper foil from peeling off at the edge under thermal cycling or mechanical vibration.

[0025] Synthetic resin 5 is composed of epoxy resin and polyimide resin mixed in a mass ratio of 3:1. Nano-silica particles are added to synthetic resin 5, and these particles are uniformly dispersed throughout the resin. The addition of nano-silica particles significantly improves the elastic modulus and creep resistance of synthetic resin 5. Their uniform dispersion allows the resin to form an isotropic reinforcing network during curing, suppressing internal microcracks caused by resin shrinkage. It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this invention is defined by the appended claims rather than the foregoing description, and all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A warp-resistant copper-clad laminate, comprising a substrate, the surface of which is covered with a copper foil layer, characterized in that: The substrate is composed of three functional layers stacked together along the thickness direction, including a substrate layer located in the middle, a first stress-adjusting layer disposed on one side of the substrate layer, and a second stress-adjusting layer disposed on the side of the substrate layer away from the first stress-adjusting layer. The first stress-adjusting layer is a grid structure composed of continuously distributed rhombic units, and the second stress-adjusting layer is a honeycomb grid structure composed of multiple regular hexagonal through holes. The first stress-adjusting layer and the second stress-adjusting layer are arranged in an alternating symmetrical manner along the thickness direction of the substrate body. The connection points of the rhombic units of the first stress-adjusting layer and the midpoints of the edges of the regular hexagonal through holes of the second stress-adjusting layer form a vertical projection correspondence. The surfaces of the substrate layer, the first stress-adjusting layer, and the second stress-adjusting layer are wrapped with synthetic resin, and a copper foil layer is hot-pressed onto the surface of the synthetic resin.

2. The anti-warping copper-clad laminate according to claim 1, characterized in that: The substrate layer is embedded with a grid-like frame structure formed by the interlacing of transverse and longitudinal reinforcing ribs. The intersection of the transverse and longitudinal reinforcing ribs forms an upwardly protruding hemispherical node. The node corresponds to the thickness of the first stress adjustment layer and the second stress adjustment layer. The hemispherical node can be paired and inserted into the grid of the first stress adjustment layer and the second stress adjustment layer.

3. The anti-warping copper-clad laminate according to claim 2, characterized in that: The substrate layer is made of wood pulp paper, and the surface of the wood pulp paper is embossed to form hemispherical nodes.

4. A copper-clad laminate for preventing warping according to any one of claims 1-3, characterized in that: The copper foil layer has a chamfered edge that bends towards the substrate, with a chamfer angle of 30-60°, and the end of the chamfer is embedded in the synthetic resin.

5. A copper-clad laminate for preventing warping according to any one of claims 1-3, characterized in that: The synthetic resin contains nano-silica particles, which are uniformly dispersed throughout the synthetic resin.

6. A copper-clad laminate for preventing warping according to any one of claims 1-3, characterized in that: The first stress-adjusting layer has a rhombus unit side length of 0.8-1.5 mm and a grid line width of 0.1-0.3 mm. The second stress-adjusting layer has a regular hexagonal through-hole side length of 0.5-0.8 mm and a hole wall thickness of 0.05-0.1 mm.

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