Copper foil substrate

Abstract

The utility model relates to a copper foil substrate which comprises a middle layer and a pair of copper foil outer layers, the middle layer comprises resin, first glass fiber cloth, second glass fiber cloth and third glass fiber cloth, and the resin wraps the first glass fiber cloth, the second glass fiber cloth and the third glass fiber cloth which are sequentially stacked. The second glass fiber cloth is thicker than the first glass fiber cloth and the third glass fiber cloth, the middle layer is provided with through holes penetrating through the resin, the first glass fiber cloth, the second glass fiber cloth and the third glass fiber cloth, and the copper foil outer layers are arranged on the upper side and the lower side of the middle layer respectively; therefore, the perforated hole of the copper foil substrate can be effectively prevented from generating pores in the subsequent electroplating process.

Description

Technical Field

[0001] This utility model relates to the field of printed circuit boards, and in particular to a copper foil substrate. Background Technology

[0002] With the rapid development of electronic technology, printed circuit boards (PCBs) have been widely used in various fields. Copper clad laminate (CCL) is the main substrate material for PCBs, providing good conductivity to allow electronic signals to be transmitted between different electronic components, while also providing insulation to prevent short circuits between components. A copper clad laminate mainly consists of one or more layers of resin-impregnated fiberglass cloth sandwiched between two copper foil layers. To meet different needs, some thicker copper clad laminates (containing two or more layers of fiberglass cloth) require the formation of small-diameter through-holes, which are then electroplated to create conductivity for electronic signal transmission.

[0003] However, when machining small-diameter through-holes into thicker copper foil substrates, the high aspect ratio makes conventional drilling methods difficult. Therefore, many manufacturers use laser processing to burn through the copper foil substrate. However, as... Figure 1 As shown, since copper foil substrates with two or more layers of fiberglass cloth generally use fiberglass cloth of the same thickness, and lasers themselves contain a huge amount of energy, it takes more time and energy to burn through the harder fiberglass cloth than resin. This results in a significant difference between the inner diameter of the through-holes formed after laser processing at each fiberglass cloth and the inner diameter of the resin between each fiberglass cloth. This makes it easy for pores (S) to be generated at the resin between each fiberglass cloth during subsequent electroplating, thereby increasing the resistance and reliability risk of the copper foil substrate.

[0004] In view of this, the inventors have devoted themselves to research and applied theoretical principles to address the shortcomings of the prior art, and have made every effort to solve the above problems, which is the goal of the inventors' improvement. Utility Model Content

[0005] The main purpose of this invention is to effectively prevent the perforations in the copper foil substrate from creating pores during subsequent electroplating.

[0006] In order to achieve the above object, the present application provides a copper foil substrate, comprising an intermediate layer and a pair of copper foil outer layers, the intermediate layer comprises a resin, a first glass fiber cloth, a second glass fiber cloth and a third glass fiber cloth, the resin wraps the first glass fiber cloth, the second glass fiber cloth and the third glass fiber cloth which are sequentially stacked, the thickness of the second glass fiber cloth is greater than the thickness of the first glass fiber cloth and the thickness of the third glass fiber cloth, the intermediate layer has a through hole penetrating through the resin, the first glass fiber cloth, the second glass fiber cloth and the third glass fiber cloth, and each copper foil outer layer is arranged on the upper and lower sides of the intermediate layer.

[0007] In an embodiment of the present application, the inner diameter of the through hole at the second glass fiber cloth is smaller than the inner diameter of the through hole at the first glass fiber cloth and the inner diameter of the through hole at the third glass fiber cloth.

[0008] In an embodiment of the present application, the first glass fiber cloth comprises a plurality of first glass fiber bundles which are interlaced with each other, the second glass fiber cloth comprises a plurality of second glass fiber bundles which are interlaced with each other, and the third glass fiber cloth comprises a plurality of third glass fiber bundles which are interlaced with each other, each first glass fiber bundle comprises a plurality of first glass fiber filaments, each second glass fiber bundle comprises a plurality of second glass fiber filaments, and each third glass fiber bundle comprises a plurality of third glass fiber filaments.

[0009] In an embodiment of the present application, the outer diameter of each second glass fiber filament in each second glass fiber bundle is greater than the outer diameter of each first glass fiber filament in each first glass fiber bundle and the outer diameter of each third glass fiber filament in each third glass fiber bundle.

[0010] In an embodiment of the present application, the density of each second glass fiber filament in each second glass fiber bundle is greater than the density of each first glass fiber filament in each first glass fiber bundle and the density of each third glass fiber filament in each third glass fiber bundle.

[0011] In an embodiment of the present application, the ratio of the thickness of the second glass fiber cloth to the thickness of the first glass fiber cloth is greater than 1.5.

[0012] In an embodiment of the present application, the ratio of the thickness of the second glass fiber cloth to the thickness of the third glass fiber cloth is greater than 1.5.

[0013] In an embodiment of the present application, the thickness of the first glass fiber cloth is the same as the thickness of the third glass fiber cloth.

[0014] In an embodiment of the present application, each copper foil outer layer has an outer surface away from the intermediate layer, a substrate thickness is formed between the outer surfaces, the through hole has an average inner diameter, and the ratio of the substrate thickness to the average inner diameter is greater than 1.

[0015] In an embodiment of the present application, a conductor is further included, which is filled in the perforation.

[0016] The copper foil substrate of the present application can effectively avoid the perforation of the copper foil substrate from generating pores in the subsequent electroplating process, because the thickness of the second glass fiber cloth is greater than the thickness of the first glass fiber cloth and the thickness of the third glass fiber cloth. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a cross-sectional side view of a known technology of a copper foil substrate.

[0018] Figure 2 is a cross-sectional side view of the present application.

[0019] Figure 3 is a cross-sectional side view of another embodiment of the present application.

[0020] REFERENCE NUMERALS

[0021] 10: intermediate layer

[0022] 101: perforation

[0023] 11: resin

[0024] 12: first glass fiber cloth

[0025] 121: first glass fiber bundle

[0026] 1211: first glass fiber filament

[0027] 13: second glass fiber cloth

[0028] 131: second glass fiber bundle

[0029] 1311: second glass fiber filament

[0030] 14: third glass fiber cloth

[0031] 141: third glass fiber bundle

[0032] 1411: third glass fiber filament

[0033] 20: copper foil outer layer

[0034] 21: outer surface

[0035] 30: conductor

[0036] T: substrate thickness

[0037] D: average inner diameter

[0038] S: pore DETAILED DESCRIPTION

[0039] In the description of the present application, it needs to be understood that the terms "front side", "rear side", "left side", "right side", "front end", "rear end", "end", "longitudinal", "lateral", "vertical", "top", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or component referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as a limitation on the present application.

[0040] As used herein, terms such as "first", "second", "third", "fourth" and "fifth" describe various components, elements, regions, levels, or portions, which should not be limited by these terms. These terms can only be used to distinguish one element, component, region, level or portion from another. Unless the context clearly indicates otherwise, the terms "first", "second", "third", "fourth" and "fifth" used herein do not imply order or sequence.

[0041] As used herein and unless otherwise defined, the terms "substantially" and "approximately" are used to describe and account for small variations. When used in connection with an event or circumstance, the terms can include the exact occurrence of the event or circumstance, as well as the occurrence of the event or circumstance to a close approximation. For example, when used in connection with a numerical value, the terms can include a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

[0042] The detailed description and technical content of the present application will be described below with reference to the accompanying drawings, however the drawings are only for illustrative purposes and are not intended to limit the present application.

[0043] The present application provides a copper foil substrate, i.e. a copper foil laminate (CCL), which is the main base material of a printed circuit board (PCB). Please refer to Figure 2 and Figure 3 The copper foil substrate of the present application mainly includes an intermediate layer 10 and a pair of copper foil outer layers 20.

[0044] In the embodiment, the intermediate layer 10 includes a resin 11, a first glass fiber cloth 12, a second glass fiber cloth 13 and a third glass fiber cloth 14, but in other embodiments, more glass fiber cloths or other mixed materials can also be included, and the utility model is not limited to this. The first glass fiber cloth 12, the second glass fiber cloth 13 and the third glass fiber cloth 14 are substantially sequentially stacked. The resin 11 covers the first glass fiber cloth 12, the second glass fiber cloth 13 and the third glass fiber cloth 14 which are sequentially stacked. It should be noted that the first glass fiber cloth 12, the second glass fiber cloth 13 and the third glass fiber cloth 14 are sequentially stacked, but are not limited to being stacked with each other, but can also be spaced apart. The thickness of the second glass fiber cloth 13 is greater than the thickness of the first glass fiber cloth 12, and the thickness of the second glass fiber cloth 13 is also greater than the thickness of the third glass fiber cloth 14. The intermediate layer 10 has a through hole 101 which penetrates through the resin 11, the first glass fiber cloth 12, the second glass fiber cloth 13 and the third glass fiber cloth 14. In the embodiment, the through hole 101 is substantially perpendicular to the stacking direction of the first glass fiber cloth 12, the second glass fiber cloth 13 and the third glass fiber cloth 14, but the utility model is not limited to this.

[0045] Each copper foil outer layer 20 is arranged on the upper and lower sides of the intermediate layer 10. Specifically, the intermediate layer 10 is combined and sandwiched between each copper foil outer layer 20. Each copper foil outer layer 20 has an outer surface 21 away from the intermediate layer 10. A substrate thickness T is formed between each outer surface 21, and the through hole 101 has an average inner diameter D. The ratio of the substrate thickness T to the average inner diameter D is greater than 1, that is, the substrate thickness T is greater than the average inner diameter D. In the embodiment, the ratio of the substrate thickness T to the average inner diameter D is greater than 2, that is, the copper foil substrate in the embodiment has a small hole diameter high hole depth ratio (aspect ratio) characteristic, so laser processing is mostly needed to form the through hole 101, but the utility model is not limited to the ratio being greater than 2, as long as the substrate thickness T is greater than the average inner diameter D.

[0046] The copper foil substrate has a high hole depth ratio of the small-aperture perforation 101, and the thickness of the second glass fiber cloth 13 is greater than the thickness of the first glass fiber cloth 12 and the thickness of the third glass fiber cloth 14, so that when the copper foil substrate is subjected to laser processing to form the perforation 101, the high-temperature laser can quickly penetrate the first glass fiber cloth 12 and the third glass fiber cloth 14 and the resin 11 around the first glass fiber cloth 12 and the third glass fiber cloth 14, but a large amount of energy is required to penetrate the second glass fiber cloth 13 and the resin 11 around the second glass fiber cloth 13, so that the inner diameter of the perforation 101 at the second glass fiber cloth 13 is smaller than the inner diameter of the perforation 101 at the first glass fiber cloth 12, and the inner diameter of the perforation 101 at the second glass fiber cloth 13 is also smaller than the inner diameter of the perforation 101 at the third glass fiber cloth 14. Therefore, when the perforation 101 of the copper foil substrate of the utility model is subjected to subsequent electroplating process, the conductive material such as copper or graphite will first deposit and stack at the smaller inner diameter of the perforation 101 corresponding to the second glass fiber cloth 13, and then extend to the first glass fiber cloth 12 and the third glass fiber cloth 14 to deposit and stack, thereby effectively avoiding the generation of pore holes in the conductive material during the electroplating process, and further reducing the resistance and reliability risk of the conductive material.

[0047] Further, the first glass fiber cloth 12 includes a plurality of first glass fiber bundles 121 that are interlaced with each other, the second glass fiber cloth 13 includes a plurality of second glass fiber bundles 131 that are interlaced with each other, and the third glass fiber cloth 14 includes a plurality of third glass fiber bundles 141 that are interlaced with each other. In other words, the first glass fiber cloth 12 is formed by the first glass fiber bundles 121 being interlaced with each other in the warp direction and the weft direction to form a mesh-like structure, and the same applies to the second glass fiber cloth 13 and the third glass fiber cloth 14, so no further description is given. In addition, each first glass fiber bundle 121 includes a plurality of first glass fiber filaments 1211, each second glass fiber bundle 131 includes a plurality of second glass fiber filaments 1311, and each third glass fiber bundle 141 includes a plurality of third glass fiber filaments 1411. In this embodiment, the outer diameter of each second glass fiber filament 1311 in each second glass fiber bundle 131 is greater than the outer diameter of each first glass fiber filament 1211 in each first glass fiber bundle 121, and the outer diameter of each second glass fiber filament 1311 in each second glass fiber bundle 131 is also greater than the outer diameter of each third glass fiber filament 1411 in each third glass fiber bundle 141, so that the thickness of the second glass fiber cloth 13 is greater than the thickness of the first glass fiber cloth 12 and the thickness of the third glass fiber cloth 14, and the inner diameter of the perforation 101 at the second glass fiber cloth 13 is smaller than the inner diameter of the perforation 101 at the first glass fiber cloth 12 and the inner diameter of the perforation 101 at the third glass fiber cloth 14, but the utility model is not limited thereto.

[0048] For example, Figure 3 The second glass fiber cloth 13 is another embodiment of the utility model, and the main difference is that the density of each second glass fiber filament 1311 in each second glass fiber bundle 131 in the second glass fiber cloth 13 is greater than the density of each first glass fiber filament 1211 in each first glass fiber bundle 121 in the first glass fiber cloth 12, and the density of each second glass fiber filament 1311 in each second glass fiber bundle 131 in the second glass fiber cloth 13 is also greater than the density of each third glass fiber filament 1411 in each third glass fiber bundle 141 in the third glass fiber cloth 14. Therefore, the thickness of the second glass fiber cloth 13 in the embodiment can also be greater than the thickness of the first glass fiber cloth 12 and the thickness of the third glass fiber cloth 14 at the same time, so that the inner diameter of the perforation 101 at the second glass fiber cloth 13 is smaller than the inner diameter of the perforation 101 at the first glass fiber cloth 12 and the inner diameter of the perforation 101 at the third glass fiber cloth 14 at the same time.

[0049] Further, the ratio of the thickness of the second glass fiber cloth 13 to the thickness of the first glass fiber cloth 12 is greater than 1.5, and the ratio of the thickness of the second glass fiber cloth 13 to the thickness of the third glass fiber cloth 14 is greater than 1.5, so that the inner diameter of the perforation 101 can reach a certain degree of difference at the first glass fiber cloth 12, the second glass fiber cloth 13 and the third glass fiber cloth 14 when laser processing. In the embodiment, the thickness of the first glass fiber cloth 12 is the same as the thickness of the third glass fiber cloth 14, that is, each first glass fiber bundle 121 used by the first glass fiber cloth 12 and each second glass fiber bundle 131 used by the second glass fiber cloth 13 can be glass fiber bundles of the same model and size, but the utility model is not limited thereto.

[0050] In addition, the copper foil substrate of the utility model further includes a conductor 30. The conductor 30 is completely filled in the perforation 101, so that there is no pore hole in the perforation 101, so that the resistance and reliability risk of the conductor 30 can be reduced, and the use performance of the copper foil substrate is improved. In the embodiment, the conductor 30 is copper, so the conductor 30 can be formed together with each copper foil outer layer 20, but the utility model is not limited thereto, for example, the conductor 30 can also be graphite or other conductive materials.

[0051] The copper foil substrate of the utility model, the thickness of the second glass fiber cloth 13 is greater than the thickness of the first glass fiber cloth 12 and the thickness of the third glass fiber cloth 14, so that the perforation 101 of the copper foil substrate of the utility model can be effectively avoided during the subsequent electroplating process.

[0052] To sum up, the foregoing disclosed content of the utility model is for letting the person with ordinary skill in the art can clearly understand the technical content of the utility model and implementation, and is not intended to limit the patent protection scope of the utility model. In addition, the utility model can of course have other unlisted various embodiments, and the person skilled in the art should be able to evolve various corresponding changes and deformations according to the utility model without departing from the spirit and essence of the utility model, but these corresponding changes and deformations should all belong to the protection scope of the patent applied for by the utility model.

Claims

1. A copper foil substrate, comprising: an intermediate layer including a resin, a first glass fiber cloth, a second glass fiber cloth, and a third glass fiber cloth, the resin wrapping the first glass fiber cloth, the second glass fiber cloth, and the third glass fiber cloth which are sequentially stacked, a thickness of the second glass fiber cloth being greater than a thickness of the first glass fiber cloth and a thickness of the third glass fiber cloth, the intermediate layer having a through hole penetrating through the resin, the first glass fiber cloth, the second glass fiber cloth, and the third glass fiber cloth; and a pair of copper foil outer layers respectively arranged on upper and lower sides of the intermediate layer.

2. The copper foil substrate of claim 1, wherein An inner diameter of the through hole at the second glass fiber cloth is smaller than an inner diameter of the through hole at the first glass fiber cloth and an inner diameter of the through hole at the third glass fiber cloth.

3. The copper foil substrate of claim 1, wherein The first glass fiber cloth includes a plurality of first glass fiber bundles which are interlaced with each other, the second glass fiber cloth includes a plurality of second glass fiber bundles which are interlaced with each other, and the third glass fiber cloth includes a plurality of third glass fiber bundles which are interlaced with each other, each of the first glass fiber bundles includes a plurality of first glass fiber filaments, each of the second glass fiber bundles includes a plurality of second glass fiber filaments, and each of the third glass fiber bundles includes a plurality of third glass fiber filaments.

4. The copper foil substrate of claim 3, wherein An outer diameter of each of the second glass fiber filaments in each of the second glass fiber bundles is greater than an outer diameter of each of the first glass fiber filaments in each of the first glass fiber bundles and an outer diameter of each of the third glass fiber filaments in each of the third glass fiber bundles.

5. The copper foil substrate of claim 3, wherein A density of each of the second glass fiber filaments in each of the second glass fiber bundles is greater than a density of each of the first glass fiber filaments in each of the first glass fiber bundles and a density of each of the third glass fiber filaments in each of the third glass fiber bundles.

6. The copper foil substrate of claim 1, wherein A ratio of the thickness of the second glass fiber cloth to the thickness of the first glass fiber cloth is greater than 1.

5.

7. The copper foil substrate of claim 1, wherein A ratio of the thickness of the second glass fiber cloth to the thickness of the third glass fiber cloth is greater than 1.

5.

8. The copper foil substrate of claim 1, wherein The thickness of the first glass fiber cloth is the same as the thickness of the third glass fiber cloth.

9. The copper foil substrate of claim 1, wherein Each of the copper foil outer layers has an outer surface away from the intermediate layer, a substrate thickness is formed between the outer surfaces, the through hole has an average inner diameter, and a ratio of the substrate thickness to the average inner diameter is greater than 1.

10. The copper foil substrate according to any one of claims 1 to 9, characterized in that A conductor is further included, the conductor being filled in the through hole.

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