阅读说明：本技术 电路板及其制备方法 (Circuit board and preparation method thereof ) 是由 李保忠 于 2021-10-07 设计创作，主要内容包括：本发明实施例公开了一种电路板及其制备方法。其中,电路板包括绝缘基板、导电线路、以及贯穿绝缘基板设置的铝或铝合金导热件；铝或铝合金导热件的至少一个表面具有铝阳极氧化绝缘层和导热凸台,导热凸台暴露于铝阳极氧化绝缘层；铝阳极氧化绝缘层的孔隙内填充有树脂,导电线路形成在铝阳极氧化绝缘层和绝缘基板的表面。本发明中,铝或铝合金导热件的表面形成有铝阳极氧化绝缘层和导热凸台,在提高散热性能的同时,使得电路板表面具有较大的布线面积,便于电路板的小型化；铝阳极氧化绝缘层的孔隙内填充有树脂,有利于增强铝阳极氧化绝缘层的电绝缘性能及其与导电线路的结合力。(The embodiment of the invention discloses a circuit board and a preparation method thereof. The circuit board comprises an insulating substrate, a conductive circuit and an aluminum or aluminum alloy heat conducting piece which penetrates through the insulating substrate; at least one surface of the aluminum or aluminum alloy heat conducting piece is provided with an aluminum anodic oxidation insulating layer and a heat conducting boss, and the heat conducting boss is exposed to the aluminum anodic oxidation insulating layer; resin is filled in the pores of the aluminum anodic oxidation insulating layer, and the conducting circuit is formed on the surfaces of the aluminum anodic oxidation insulating layer and the insulating substrate. In the invention, the surface of the aluminum or aluminum alloy heat conducting piece is provided with the aluminum anodic oxidation insulating layer and the heat conducting boss, so that the surface of the circuit board has larger wiring area while the heat dissipation performance is improved, and the miniaturization of the circuit board is facilitated; the pores of the aluminum anodic oxidation insulating layer are filled with resin, which is beneficial to enhancing the electrical insulating property of the aluminum anodic oxidation insulating layer and the binding force between the aluminum anodic oxidation insulating layer and the conducting circuit.)

1. A circuit board comprises an insulating substrate, a conductive circuit and an aluminum or aluminum alloy heat-conducting piece which penetrates through the insulating substrate; the method is characterized in that: at least one surface of the aluminum or aluminum alloy heat conducting piece is provided with an aluminum anodic oxidation insulating layer and a heat conducting boss, and the heat conducting boss is exposed to the aluminum anodic oxidation insulating layer; resin is filled in the pores of the aluminum anodic oxidation insulating layer, and the conducting circuit is formed on the surfaces of the aluminum anodic oxidation insulating layer and the insulating substrate.

2. The circuit board of claim 1, wherein: the thickness of the aluminum anodic oxidation insulating layer is 10-80 μm.

3. The circuit board of claim 1, wherein: and a heat conduction welding pad is formed on the heat conduction boss and is flush with the surface of the conductive circuit.

4. The circuit board of claim 1, wherein: the insulating substrate comprises a plurality of layers of insulating core plates, and the insulating core plates and the insulating substrate and the aluminum or aluminum alloy heat-conducting piece are connected in a bonding mode through adhesive materials.

5. The circuit board of claim 1, wherein: the top surface and the bottom surface of the aluminum or aluminum alloy heat conducting piece are both provided with the aluminum anodic oxidation insulating layer and the heat conducting lug boss.

6. The circuit board of claim 1, wherein: the top surface of the aluminum or aluminum alloy heat conducting piece is provided with the aluminum anodic oxidation insulating layer and the heat conducting boss; the bottom surface of the circuit board is provided with a heat dissipation metal layer, and the bottom surface of the aluminum or aluminum alloy heat conducting piece is in thermal connection with the heat dissipation metal layer.

7. A circuit board preparation method is characterized by comprising the following steps:

s1, carrying out local anodic oxidation treatment on at least one surface of the aluminum or aluminum alloy heat conducting piece to form an aluminum anodic oxidation insulating layer and a heat conducting boss on the surface;

s2, filling resin in the aluminum anodic oxidation insulating layer;

s3, fixing the aluminum or aluminum alloy heat conducting piece obtained in the step S2 into an insulating substrate of the circuit board;

s4, forming a copper-clad layer on the surface of the circuit board obtained in the step S3;

and S5, manufacturing conductive circuits on the surfaces of the aluminum anodic oxidation insulating layer and the insulating substrate.

8. The method for preparing a circuit board according to claim 7, wherein the step S2 includes:

s21, immersing the aluminum or aluminum alloy heat-conducting piece after the partial anodic oxidation into liquid resin, or coating the liquid resin on the surface of the aluminum anodic oxidation insulating layer, so that the liquid resin enters the pores of the aluminum anodic oxidation insulating layer;

s22, pre-curing the liquid resin, and grinding to remove the redundant resin on the surface of the circuit board after pre-curing;

and S23, performing post-curing treatment on the resin in the aluminum anodic oxidation insulating layer.

9. The method for preparing a circuit board according to claim 7, wherein the step S3 includes:

s311, windowing the insulating core board and the prepreg;

s312, stacking the multiple layers of insulating core boards, and placing prepregs between the insulating core boards;

s313, placing the aluminum or aluminum alloy heat-conducting piece obtained in the step S2 at the windowing position of the insulating core board and the prepreg, and pressing the multilayer insulating core board to form an insulating substrate and fixing the aluminum or aluminum alloy heat-conducting piece in the insulating substrate.

10. The method for preparing a circuit board according to claim 7, wherein the step S3 includes:

s321, performing windowing treatment on an insulating substrate of the circuit board;

s322, placing the aluminum or aluminum alloy heat-conducting piece obtained in the step S2 at the windowing position of the insulating substrate, and filling hole plugging resin in a pore between the aluminum or aluminum alloy heat-conducting piece and the insulating substrate so as to fix the aluminum or aluminum alloy heat-conducting piece in the insulating substrate.

Technical Field

The invention relates to the field of circuit boards; and more particularly, to a circuit board having an aluminum or aluminum alloy heat conductive member embedded in an insulating substrate and a method of manufacturing the same.

Background

In the prior art, a metal heat conducting part is usually embedded in the component mounting position of a circuit board, and the metal heat conducting part can be arranged to be an insulating substrate penetrating through the circuit board, so that a heat conducting channel penetrating through the insulating substrate is formed, and rapid heat dissipation of components is realized.

In many cases, it is required to embed a metal heat conducting member with a large size to realize rapid heat dissipation of the device, but because the metal heat conducting member has electrical conductivity, the conductive circuit can only be fabricated on the insulating substrate of the circuit board, which not only affects the surface wiring of the circuit board, but also causes the area of the circuit board to be significantly increased when the size of the metal heat conducting member is large, which is not favorable for the miniaturization of the circuit board.

Disclosure of Invention

In view of the deficiencies of the prior art, the main objective of the present invention is to provide a circuit board with an aluminum or aluminum alloy heat conducting member embedded in an insulating substrate and a method for manufacturing the same, which can improve the heat dissipation performance of the circuit board without affecting the surface wiring of the circuit board.

In order to achieve the above-mentioned primary object, a first aspect of the present invention discloses a circuit board including an insulating substrate, a conductive circuit, and an aluminum or aluminum alloy heat-conducting member disposed through the insulating substrate; at least one surface of the aluminum or aluminum alloy heat conducting piece is provided with an aluminum anodic oxidation insulating layer and a heat conducting boss, and the heat conducting boss is exposed to the aluminum anodic oxidation insulating layer; resin is filled in the pores of the aluminum anodic oxidation insulating layer, and the conducting circuit is formed on the surfaces of the aluminum anodic oxidation insulating layer and the insulating substrate.

According to a particular embodiment of the first aspect of the invention, the aluminum anodized insulation layer has a thickness of 10 μm to 80 μm.

According to a specific implementation manner of the first aspect of the present invention, the heat conducting pad is formed on the heat conducting boss, and the heat conducting pad is flush with the surface of the conductive circuit, so as to facilitate mounting of the component.

According to a specific embodiment of the first aspect of the present invention, the insulating substrate includes a plurality of insulating core sheets, and the insulating substrate and the aluminum or aluminum alloy heat-conducting member are bonded and connected by an adhesive material.

According to a specific embodiment of the first aspect of the present invention, the aluminum or aluminum alloy heat conductive member has an aluminum anodized insulation layer and a heat conductive projection on both top and bottom surfaces thereof.

According to another specific embodiment of the first aspect of the present invention, the top surface of the aluminum or aluminum alloy heat conductive member has an oxide insulating layer and a heat conductive boss; the bottom surface of the circuit board is provided with a heat dissipation metal layer, and the bottom surface of the aluminum or aluminum alloy heat conducting piece is in thermal connection with the heat dissipation metal layer.

In order to achieve the above main object, a second aspect of the present invention provides a circuit board manufacturing method, including the steps of:

s1, carrying out local anodic oxidation treatment on at least one surface of the aluminum or aluminum alloy heat conducting piece to form an aluminum anodic oxidation insulating layer and a heat conducting boss on the surface;

s2, filling resin in the aluminum anodic oxidation insulating layer;

s3, fixing the aluminum or aluminum alloy heat conducting piece obtained in the step S2 into an insulating substrate of the circuit board;

s4, forming a copper-clad layer on the surface of the circuit board obtained in the step S3;

and S5, forming conductive circuits on the surfaces of the aluminum anodic oxidation insulating layer and the insulating substrate.

According to a specific embodiment of the second aspect of the present invention, the step S2 includes:

s21, immersing the aluminum or aluminum alloy heat-conducting piece after the partial anodic oxidation into liquid resin, or coating the liquid resin on the surface of the aluminum anodic oxidation insulating layer, so that the liquid resin enters the pores of the aluminum anodic oxidation insulating layer;

s22, pre-curing the liquid resin, and grinding to remove the redundant resin on the surface of the circuit board after pre-curing;

and S23, performing post-curing treatment on the resin in the aluminum anodic oxidation insulating layer.

According to a specific embodiment of the second aspect of the present invention, the step S3 includes:

s311, windowing the insulating core board and the prepreg;

s312, stacking the multiple layers of insulating core boards, and placing prepregs between the insulating core boards;

s313, placing the aluminum or aluminum alloy heat-conducting piece obtained in the step S2 at the windowing positions of the insulating core board and the prepreg, and pressing the multiple layers of insulating core boards to form an insulating substrate and fixing the aluminum or aluminum alloy heat-conducting piece in the insulating substrate.

According to a specific embodiment of the second aspect of the present invention, the step S3 includes:

s321, performing windowing treatment on an insulating substrate of the circuit board;

s322, placing the aluminum or aluminum alloy heat-conducting piece obtained in the step S2 at the windowing position of the insulating substrate, and filling hole-plugging resin in a hole between the aluminum or aluminum alloy heat-conducting piece and the insulating substrate so as to fix the aluminum or aluminum alloy heat-conducting piece in the insulating substrate.

The invention has the following beneficial effects: the conducting circuit is formed on the surfaces of the aluminum anode oxidation insulating layer and the insulating substrate, so that the surface of the circuit board has a larger wiring area, and the miniaturization of the circuit board is facilitated; the heat conduction boss is exposed on the aluminum anode oxidation insulating layer, so that heat conduction connection can be directly formed between the heat conduction boss and the component, and the circuit board has excellent heat dissipation performance. Furthermore, resin is filled in the pores of the aluminum anodic oxidation insulating layer to enhance the bonding force between the aluminum anodic oxidation insulating layer and the conductive circuit and improve the electrical insulation performance of the aluminum anodic oxidation insulating layer.

To more clearly illustrate the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the accompanying drawings and detailed description.

Drawings

Fig. 1 is a schematic structural view of a circuit board in embodiment 1 of the present invention;

FIG. 2 is a schematic view of a laminated structure of an insulating core board and a prepreg in example 1 of the present invention;

fig. 3 is a schematic structural view of an aluminum or aluminum alloy heat-conducting member fixed in an insulating core board by press-fitting in embodiment 1 of the present invention;

FIG. 4 is a schematic structural view of a circuit board having a copper-clad layer formed on a surface thereof according to embodiment 1 of the present invention;

fig. 5 is a schematic structural diagram of a circuit board after etching a conductive trace according to embodiment 1 of the present invention;

fig. 6 is a schematic structural view of a circuit board in embodiment 2 of the present invention;

FIG. 7 is a schematic view of a structure of an insulating substrate after windowing in embodiment 2 of the present invention;

fig. 8 is a schematic structural view of fixing an aluminum or aluminum alloy heat-conductive member in an insulating core plate through resin plugs in embodiment 2 of the present invention;

fig. 9 is a schematic structural diagram of a circuit board in embodiment 3 of the present invention.

It should be noted that, in order to clearly illustrate the structures that are being represented, the various parts of the drawings may not be drawn to the same scale. Therefore, unless explicitly stated otherwise, the drawings do not limit the dimensions and proportional relationships of the heat dissipation substrate.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced with other variations that are based on the description. Therefore, other possible implementations that can be recognized by those skilled in the art based on the following examples are within the scope of the present invention.

Example 1

As shown in fig. 1, the circuit board of embodiment 1 includes an insulating substrate 10 and an aluminum or aluminum alloy heat conductive member 20 disposed through the insulating substrate 10, a heat dissipation metal layer 40 may be disposed on a bottom surface of the insulating substrate 10 (i.e., a bottom surface of the circuit board), and the bottom surface of the aluminum or aluminum alloy heat conductive member 20 is thermally connected to the heat dissipation metal layer 40.

In the invention, the insulating substrate 10 comprises a plurality of insulating core plates 11, and the insulating core plates 11 and the insulating substrate 10 and the aluminum or aluminum alloy heat-conducting member 20 are bonded and connected through prepregs 12. Among them, the aluminum or aluminum alloy heat-conductive member 20 is preferably an aluminum-silicon alloy heat-conductive member, such as 4045 or 4047 aluminum-silicon alloy heat-conductive member; the insulating core 11 may be an FR-4 core, but the invention is not limited thereto.

In embodiment 1, the top surface of the aluminum or aluminum alloy heat conductive member 20 is formed with an aluminum anodized insulation layer 21 and a heat conductive boss 22 exposed to the aluminum anodized insulation layer 21. The thickness of the aluminum anodized insulation layer 21 may be 10 to 80 μm, and more specifically, may be 20 to 60 μm.

The aluminum anodized insulation layer 21 and the surface of the insulation substrate 10 are formed with a conductive line 30, the conductive line 30 includes a first line region 31 formed on the surface of the aluminum anodized insulation layer 21 and a second line region 32 formed on the surface of the insulation substrate 10, and the thickness of the first line region 31 is smaller than that of the second line region. Further, a heat conducting pad 23 may be formed on the heat conducting boss 22, and the heat conducting pad 23 may be flush with the surface of the conductive trace 30 and completely cover the heat conducting boss 22, so as to facilitate mounting of components on the circuit board; after mounting, thermal connection is formed between the component and the thermal pad 23, and electrical connection is formed between the component and the conductive trace 30.

In general, the aluminum anodized insulation layer 21 forms a porous honeycomb structure, and the inventors found that the bonding force between the aluminum anodized insulation layer 21 and the conductive circuit is reduced. In the present invention, the pores of the aluminum anodized insulation layer 21 are filled with resin to enhance the bonding force between the aluminum anodized insulation layer 21 and the first line region 31 and the electrical insulation performance of the anodized insulation layer 21.

Specifically, in the method for manufacturing the circuit board of embodiment 1, the top surface of the aluminum or aluminum alloy heat-conducting member 20 is subjected to the local anodization treatment to form the aluminum anodized insulation layer 21 and the heat-conducting protrusions 22 on the surface, and then the aluminum anodized insulation layer 21 is filled with the resin.

Wherein, filling resin in the aluminum anodized insulation layer 21 may include the following steps: firstly, immersing the aluminum or aluminum alloy heat-conducting piece 20 subjected to local anodization into liquid resin, or coating the surface of the aluminum anodized insulation layer 21 with the liquid resin, so that the liquid resin enters pores of the aluminum anodized insulation layer 21; then, the liquid resin is pre-cured, and after the pre-curing, the excess resin on the surface of the circuit board (the resin covering the surface of the heat conduction boss 22) is ground and removed; finally, the resin in the aluminum anodized insulation layer 21 is post-cured.

In the circuit board manufacturing method of embodiment 1, after the resin filling treatment is performed on the aluminum anodized insulation layer 21, the aluminum or aluminum alloy heat conductive member 20 is fixed in the insulation substrate 10 by press-fitting. Specifically, as shown in fig. 3, windowing is performed on the insulated core boards 11 and the prepregs 12, then the multi-layer insulated core boards 11 are stacked, and the prepregs 12 are placed between the insulated core boards 12; then, the aluminum or aluminum alloy heat conducting member 20 is placed at the position of the insulating core board 11 and the prepreg 12, the multi-layer insulating core board 11 is pressed, after the pressing, the prepreg 12 bonds the insulating core boards 11 together to form the insulating substrate 10, and simultaneously, the prepreg 12 fills the gap between the insulating substrate 10 and the aluminum or aluminum alloy heat conducting member 20 by flowing, so that the aluminum or aluminum alloy heat conducting member 20 is fixed in the insulating substrate 10. After the pressing, the surfaces of the two sides of the circuit board can be grinded to remove the prepreg flowing to the surface of the circuit board.

The method for manufacturing a circuit board according to embodiment 1 further includes a step of forming a copper-clad layer 112 on the surface of the circuit board and a step of forming a conductive trace 30 on the surfaces of the aluminum anodized insulation layer 21 and the insulation substrate 10 after the aluminum or aluminum alloy heat conductive member 20 is fixed to the insulation substrate 10. In order to form the copper-clad layer 112 on the surface of the circuit board, the insulating substrate 10 may have copper-clad layers 111 on both surfaces thereof.

In an embodiment of the present invention, as shown in fig. 4, the circuit board may be subjected to full-scale electroless plating and electroplating in sequence to form copper-clad layers 112 on the top and bottom surfaces of the circuit board. Then, as shown in fig. 5, the copper foil layer 111 and the copper clad layer 112 on the top surface of the circuit board are subjected to patterned etching, so as to form the conductive circuit 30 and the heat conducting pad 23; the copper foil layer 111 and the copper clad layer 112 on the bottom surface of the circuit board may be formed without etching, and both constitute the heat dissipation metal layer 40.

In the embodiment of the invention, the pores of the aluminum anodized insulation layer 21 are filled with resin, so that after the circuit board is subjected to whole-board chemical plating and electroplating, no plating solution, cleaning solution and other liquid residues are left in the pores of the aluminum anodized insulation layer 21, and the aluminum anodized insulation layer 21 and the conductive circuit have good bonding force. On the other hand, if the pores of the aluminum anodized insulation layer 21 are not filled with the resin, a plating solution, a cleaning solution, or other liquid is likely to remain in the pores of the aluminum anodized insulation layer 21, and defects such as delamination and/or bubbling may occur in the conductive line formed on the surface of the aluminum anodized insulation layer 21.

Example 2

As shown in fig. 6, the circuit board of embodiment 2 includes an insulating substrate 10 and an aluminum or aluminum alloy heat conductive member 20 embedded in the insulating substrate 10. The insulating substrate 10 includes a plurality of insulating core boards 11, the insulating core boards 11 are bonded and connected by prepregs 121, and the insulating substrate 10 and the aluminum or aluminum alloy heat-conducting member 20 are bonded and connected by plugging resin 122. Other descriptions of the circuit board structure in embodiment 2 can refer to embodiment 1 and are not repeated.

In embodiment 2, the insulating core 11 and the prepreg 121 are pressed to manufacture the insulating substrate 10, and the top surface and the bottom surface of the insulating substrate 10 are both provided with the copper foil layers 111; then, as shown in fig. 7, the insulating substrate 10 is subjected to a windowing process to form a window 13 accommodating an aluminum or aluminum alloy heat conductive member 20; next, the aluminum or aluminum alloy heat-conducting member 20 is placed at the position of the insulating substrate 10 where the window is opened, and a hole-plugging resin 122 is filled in the hole between the aluminum or aluminum alloy heat-conducting member 20 and the insulating substrate 10, so as to fix the aluminum or aluminum alloy heat-conducting member 20 in the insulating substrate 10; then, copper clad layers may be formed on both side surfaces of the circuit board, and conductive traces 30 may be formed on the aluminum anodized insulation layer 21 and the surface of the insulation substrate 10. For other descriptions of the circuit board preparation method in embodiment 2, reference may be made to embodiment 1, and further description is omitted.

Example 3

As shown in fig. 3, the circuit board of embodiment 3 includes an insulating substrate 10 and an aluminum or aluminum alloy heat conductive member 20 embedded in the insulating substrate 10, the aluminum or aluminum alloy heat conductive member 20 having an oxide insulating layer 21 and a heat conductive boss 22 on both top and bottom surfaces thereof, and the circuit board having a conductive line 30 formed on the surfaces of the insulating substrate 10 and the oxide insulating layer 21 on both top and bottom surfaces thereof. For other descriptions of embodiment 3, refer to embodiment 1 and embodiment 2, and are not repeated.

The technical features in the various embodiments of the present invention may be combined with or substituted for each other. In the invention, the surface of the aluminum or aluminum alloy heat conducting piece is provided with the oxidation insulating layer and the heat conducting lug boss, so that the heat dissipation performance is improved, the surface of the circuit board has a larger wiring area, and the miniaturization of the circuit board is facilitated. Furthermore, resin is filled in the pores of the aluminum anodic oxidation insulating layer so as to enhance the electrical insulating property of the aluminum anodic oxidation insulating layer and the bonding force between the aluminum anodic oxidation insulating layer and the conductive circuit.

Although the present invention has been described above by way of examples, it should be understood that the above examples are merely illustrative of possible embodiments of the present invention and should not be construed as limiting the scope of the present invention, and that equivalent variations made by those skilled in the art in light of the present invention are intended to be covered by the scope of the appended claims.