Preparation method of circuit board and circuit board

Abstract

The invention provides a preparation method of a circuit board and the circuit board, and the method comprises the steps: obtaining a substrate, and enabling the substrate to be provided with a heat dissipation layer with a groove; a metal gasket is arranged in the groove; laminating the substrate, the heat dissipation layer and the metal gasket to form a circuit board; carrying out copper deposition and electroplating on the circuit board; etching one side, far away from the heat dissipation layer, of the circuit board so as to expose the metal gasket; and the metal gasket is taken out of the groove. According to the mode, the heat dissipation layer is laminated in the circuit board through the metal gasket, so that the problems that blistering is easy to occur during electroplating and a base material is exposed at a notch due to uneven stress of an exposed groove on a leveling line after resin hole plugging are effectively prevented, and the reliability of a product is ensured.

Description

Technical Field

[0001] The present application is applied to the technical field of copper clad laminates, and in particular relates to a method for preparing a circuit board and a circuit board. Background Art

[0002] Nowadays, as people's demand for lighter and thinner electronic products and higher performance and efficiency is getting higher and higher, the power density of PCB (Printed Circuit Board) components is constantly increasing, the requirements for PCB manufacturing technology and its quality are gradually increasing, and the heat flux will become larger and larger.

[0003] However, the common heat dissipation method in the existing PCB industry is metal-based heat dissipation. However, the existing metal-based process can no longer meet the multi-dimensional heat dissipation needs of all customers, such as ultra-high thermal conductivity, insulation heat dissipation, and Low CTE heat dissipation. It is urgent to develop a process for embedding new heat dissipation materials to meet the different needs of customers. In addition, more and more products now require the use of resin plugging processes. The Teflon gaskets commonly used in this process are prone to delamination and blistering when directly electroplated after pressing. Removing the gaskets before electroplating will cause the exposed grooves to expose the base material due to uneven force on the flattened line after the resin plugging. Summary of the invention

[0004] The present application provides a method for preparing a circuit board to solve the problem of poor heat dissipation effect of existing circuit boards.

[0005] To solve the above technical problems, the first aspect of the present application provides a method for preparing a circuit board, comprising: obtaining a substrate, on which a heat dissipation layer with a groove is provided; arranging a metal gasket in the groove; laminating the substrate, the heat dissipation layer and the metal gasket to form a circuit board; copper electroplating the circuit board; etching the side of the circuit board away from the heat dissipation layer to expose the metal gasket; and removing the metal gasket from the groove.

[0006] Among them, the step of laminating the substrate, the heat dissipation layer and the metal gasket to form a circuit board includes: processing a first notch that matches the groove at the corresponding positions of the substrate and the adhesive layer, and processing a second notch that is connected to the first notch on the substrate and the adhesive layer; stacking the substrate and the adhesive layer in sequence; placing the heat dissipation layer in the second notch, and placing the metal gasket in the first notch and the groove; laminating the substrate, the adhesive layer, the metal gasket and the heat dissipation layer to form a circuit board.

[0007] Before laminating the substrate, the heat dissipation layer and the metal gasket to form a circuit board, the step further includes: drilling at least one blind hole at one end of the metal gasket; and arranging the end of the metal gasket with the blind hole away from the heat dissipation layer.

[0008] Before the step of laminating the substrate, the heat dissipation layer and the metal gasket to form the circuit board, the step further includes: spraying a release agent on the surface of the metal gasket.

[0009] The step of copper plating the circuit board includes: plugging the conductive holes on the circuit board with resin; and flattening the resin on the surface of the circuit board and removing excess resin.

[0010] The size of the first notch is larger than the size of the groove, and after lamination, the sum of the depth of the first notch and the groove is the same as the thickness of the metal gasket.

[0011] Wherein, the heat dissipation layer is made of ceramic or diamond copper material.

[0012] Wherein, the adhesive layer is a prepreg material.

[0013] The metal gasket can be made of copper or aluminum.

[0014] In order to solve the above technical problem, the second aspect of the present application provides a circuit board, wherein the circuit board is prepared by any of the above circuit board preparation methods.

[0015] The beneficial effect of the present application is as follows: different from the prior art, the present application provides a heat dissipation layer with a groove, places a metal gasket into the groove, and then laminates the metal gasket and the heat dissipation layer and a copper layer in a substrate to form a circuit board, and then takes the metal gasket out of the circuit board to achieve the embedding of the heat dissipation layer. Laminating the heat dissipation layer with the metal gasket in the substrate can prevent blistering during electroplating and the problem of exposed grooves exposing the substrate due to uneven force on the leveling line after resin plugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a process of an embodiment of a method for preparing a circuit board of the present application;

[0017] Figure 2 This application Figure 1 A schematic diagram of the process of an embodiment of S13;

[0018] Figure 3 yes Figure 2 A schematic diagram of the cross-sectional structure of the circuit board after step S134 is completed;

[0019] Figure 4 yes Figure 1 A schematic diagram of the cross-sectional structure of the circuit board after step S14 is completed;

[0020] Figure 5 for Figure 1 A schematic diagram of the cross-sectional structure of the circuit board after step S15 is completed;

[0021] Figure 6for Figure 1 A schematic diagram of the cross-sectional structure of the circuit board after step S16 is completed;

[0022] Figure 7 The schematic diagram of the structure of the connection between the heat dissipation layer and the metal gasket in the present application is shown. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0026] See also Figure 1 , Figure 1 1 is a flow chart of an embodiment of a method for preparing a circuit board provided in the present application. It should be noted that if there is substantially the same result, the method of the present invention is not limited to Figure 1 The process sequence shown is limited. Figure 1 As shown, the method comprises the following steps:

[0027] S11: obtaining a substrate 10 , on which a heat dissipation layer 20 with a groove 201 is disposed.

[0028] In an optional embodiment, a substrate 10 is obtained, wherein the substrate 10 is a basic material for preparing a circuit board, and generally has a structure of "copper-substrate-copper". A heat dissipation layer 20 with a groove 201 is provided on the substrate 10, and the heat dissipation layer 20 is provided inside the substrate 10. A notch can be opened on the substrate 10, and the heat dissipation layer 20 is installed inside the notch. The end face of the heat dissipation layer 20 installed inside the substrate 10 away from the groove 201 is flush with the end face of the substrate 10, so that after the components are subsequently installed inside the groove 201, the heat dissipation layer 20 can be directly connected to the outside, and the heat dissipated by the components is dissipated to the outside through the heat dissipation layer 20, thereby preventing the components from being damaged due to poor heat dissipation.

[0029] In other embodiments, the heat dissipation layer 20 may also be accommodated inside the substrate 10. For example, the heat dissipation layer 20 is connected to the metal layer on the substrate 10, and the components arranged inside the substrate 10 can dissipate heat through the metal layer arranged on the substrate 10. This application does not make specific limitations here. The heat dissipation layer 20 is integrally prepared and formed according to customer needs, and can meet the heat dissipation requirements of the components installed inside the groove 201. Among them, the size of the groove 201 on the heat dissipation layer 20 can be limited as needed. For example, the size of the groove 201 is set according to the components installed inside the groove 201 as needed, and this application does not make specific limitations here.

[0030] S12 : placing a metal gasket 30 in the groove 201 .

[0031] In this embodiment, if Figure 3 and Figure 7 As shown, the metal gasket 30 is installed in the groove 201 of the heat dissipation layer 20, so as to define the position of the metal gasket 30 for subsequent preparation of the circuit board. The metal gasket 30 can be any one of copper and aluminum, and the plane size of the metal gasket 30 is the same as the size of the groove 201. In other embodiments, the metal gasket 30 can also be installed in the groove 201 of the heat dissipation layer 20 when laminating with the substrate 10, and the size of the groove 201 can also be larger than the plane size of the metal gasket 30.

[0032] S13: Laminating the substrate 10, the heat dissipation layer 20 and the metal pad 30 to form a circuit board.

[0033] Specifically, Figure 3As shown, after the metal gasket 30 is set inside the groove 201, the heat dissipation layer 20 with the metal gasket 30 is set inside the substrate 10, and the circuit board is formed by lamination through the step groove process. In this embodiment, the metal gasket 30 and the heat dissipation layer 20 are set throughout the substrate 10, that is, the height of the metal gasket 30 and the heat dissipation layer 20 is the same as the thickness of the substrate 10, so as to remove the metal gasket 30 and the heat dissipation of the heat dissipation layer 20 later. Among them, the heat dissipation layer 20 is made of ceramic or diamond copper material, and other materials with strong heat dissipation can also be used according to customer needs, so as to meet the customer's multi-dimensional heat dissipation needs such as ultra-high thermal conductivity, insulation heat dissipation, Low CTE (low coefficient of thermal expansion) heat dissipation, etc., which are not specifically limited in this application.

[0034] In this embodiment, a circuit board is formed by laminating a metal gasket 30 with a substrate 10 and a heat dissipation layer 20. Due to the high structural strength of the metal gasket 30, the metal gasket 30 will not sag inward when laminating to form the circuit board. Therefore, when the circuit board is pressed together, the uniformity of the force on the circuit board substrate 10 is ensured, the base material inside the circuit board is not exposed, and the quality of the prepared circuit board is ensured.

[0035] S14: copper electroplating is performed on the circuit board.

[0036] like Figure 4 As shown, Figure 4 for Figure 1 Schematic diagram of the cross-sectional structure of the circuit board after step S14 is completed. In an optional embodiment, after the circuit board is formed by lamination through the step groove process, the circuit board is subjected to copper electroplating to form a copper layer 50 on both side end surfaces of the laminated circuit board, which is convenient for the subsequent preparation of the circuit board. In other embodiments, copper electroplating can be performed on one side end surface of the circuit board close to the metal gasket 30 to form a copper layer 50, so that the heat dissipation layer 20 inside the substrate 10 is exposed, which is convenient for heat dissipation of components arranged in the substrate 10.

[0037] In other embodiments, the copper layer 50 may be formed on the circuit board by chemical deposition or evaporation, and the thickness of the copper layer 50 formed on the circuit board may be controlled by controlling processing parameters of the chemical deposition or evaporation processing methods.

[0038] Furthermore, the circuit board is also provided with conductive holes for connecting other external components. The conductive holes on the circuit board are given conductivity by copper plating. After copper is deposited in the conductive holes, in order to form the subsequent preparation of the circuit board, the conductive holes on the circuit board are plugged with resin to prevent the conductive holes from being blocked during the subsequent processing. The resin on the surface of the circuit board is flattened and the excess resin is removed, so that the circuit board has flatness, which is convenient for the subsequent processing of the circuit board.

[0039] S15: Etching is performed on a side of the circuit board away from the heat dissipation layer 20 to expose the metal pad 30 .

[0040] like Figure 5 As shown, Figure 5 for Figure 1 Schematic diagram of the cross-sectional structure of the circuit board after step S15 is completed. In the present embodiment, after the copper layer 50 is formed by electroplating on the circuit board, etching can be performed at the corresponding position of the metal gasket 30 provided on the circuit board, thereby exposing the metal gasket 30, so as to remove the metal gasket 30 in subsequent operations. Specifically, a barrier layer can be provided on the surface of the copper layer 50 of the circuit board, and a barrier layer can be provided in the area where the copper layer 50 does not need to be etched by using a photodevelopment processing method. Then, a cleaning liquid is used to remove the barrier layer at the corresponding position of the metal gasket 30 of the circuit board, thereby exposing the copper layer 50 under the barrier layer, and further, the exposed copper layer 50 is etched away by using an etching liquid, thereby exposing the metal gasket 30.

[0041] In an optional embodiment, after the copper layer 50 is electroplated on both side end surfaces of the circuit board, when etching the copper layer 50 on the circuit board, etching can be performed at the corresponding positions of the heat dissipation layer 20 and the metal gasket 30 on the circuit board, thereby exposing the metal gasket 30 and the heat dissipation layer 20. When the circuit board is used subsequently, the heat dissipation layer 20 can be exposed to the air, which can dissipate the heat of the components more quickly and ensure the normal operation of the components in the circuit board.

[0042] S16: Take the metal gasket 30 out of the groove 201 .

[0043] like Figure 6 As shown, Figure 6 for Figure 1 Schematic diagram of the cross-sectional structure of the circuit board after step S16 is completed. Specifically, after the metal gasket 30 is exposed, the metal gasket 30 is taken out from the circuit board by a tool.

[0044] In an alternative embodiment, if Figure 7As shown, at least one blind hole 301 is formed by drilling at one end of the metal gasket 30. In the above step S12, when the metal gasket 30 is installed in the groove 201 of the heat dissipation layer 20, the end of the metal gasket 30 with the blind hole 301 is set away from the heat dissipation layer 20. That is, before the metal gasket 30 is set in the groove 201, at least one blind hole 301 is milled at one end of the metal gasket 30. When the metal gasket 30 is installed in the groove 201, the end of the metal gasket 30 with the blind hole 301 is set away from the groove 201, that is, when the metal gasket 30 is taken out, the blind hole 301 is clamped by a tool, so that the tool is forced to take out the metal gasket 30. When the metal gasket 30 is taken out, the blind hole 301 can be clamped by a clamp, or other tools can be used. The blind hole 301 on the metal gasket 30 can be formed by drilling, water jet cutting, etc. The size of the blind hole 301 can be formed according to the size of the tool, and the application does not make specific restrictions here.

[0045] In an optional embodiment, after the blind hole 301 is drilled on the metal gasket 30, in order to better remove the metal gasket 30, before laminating the metal gasket 30 on the circuit board, a release agent is sprayed on the surface of the metal gasket 30. That is, when the metal gasket 30 with the release agent sprayed on the surface is laminated inside the circuit board, due to the effect of the release agent, the adhesion between the metal gasket 30 and the substrate 10 and the heat dissipation layer 20 is low, which reduces the bonding force between the metal gasket 30 and the substrate 10 and the heat dissipation layer 20, making it easier to remove the metal gasket 30 from the circuit board. When removing, the blind hole 301 is clamped by a tool, and the metal gasket 30 can be easily removed from the substrate 10 under the effect of the release agent, preventing the metal gasket 30 from scratching the adhesion substrate 10 when removing the metal gasket 30, thereby damaging the circuit board.

[0046] Please refer to Figure 2 , Figure 2 yes Figure 1 Specifically, the above S13 may further include the following steps:

[0047] S131: processing a first notch (not shown) matching the groove 201 at corresponding positions of the substrate 10 and the adhesive layer 40, and processing a second notch (not shown) communicating with the first notch on the substrate 10 and the adhesive layer 40.

[0048] Specifically, a first notch is opened on the substrate 10 and the adhesive layer 40 to match the groove 201. The first notch has the same plane size as the metal gasket 30, and the size of the first notch is larger than the size of the groove 201, so as to facilitate the placement of the metal gasket 30 into the first notch and the groove 201. In other embodiments, the size of the first notch may be larger than the plane size of the metal gasket 30. When the metal gasket 30 is installed inside the first notch, an adhesive layer 40 is provided between the metal gasket 30 and the substrate 10, so as to fix the metal gasket 30, and prevent the metal gasket 30 from sliding during the subsequent lamination of the circuit board, resulting in uneven force on the circuit board and depression. Similarly, by providing an adhesive layer 40 between the metal gasket 30 and the substrate 10, when the metal gasket 30 is subsequently removed, it can be prevented from scratching the substrate 10, resulting in damage to the substrate 10, thereby affecting the quality of the circuit board.

[0049] Furthermore, a second notch connected to the first notch is processed on the substrate 10 and the adhesive layer 40, and the second notch has the same plane size as the heat dissipation layer 20. In other embodiments, the second notch size is larger than the plane size of the heat dissipation layer 20. When the heat dissipation layer 20 is installed inside the substrate 10, the adhesive layer 40 is arranged between the heat dissipation layer 20 and the substrate 10, so as to fix the heat dissipation layer 20. The method of grooving the substrate 10 and the adhesive layer 40 includes: laser ablation, laser cutting, ion cutting or water jet cutting.

[0050] S132: Lay the substrate 10 and the adhesive layer 40 in sequence.

[0051] After the first notch and the second notch are processed on the substrate 10 and the adhesive layer 40, the substrate 10 and the adhesive layer 40 are stacked in sequence, and the substrate 10 and the adhesive layer 40 are stacked so that the first notch and the second notch form a notch for accommodating the metal gasket 30 and the heat dissipation layer 20, and then the metal gasket 30 and the heat dissipation layer 20 are arranged inside the corresponding notch. Among them, the adhesive layer 40 is arranged between the heat dissipation layer 20 and the substrate 10 to fix the heat dissipation layer 20, and the axes of the first notch and the second notch are on the same straight line. When the components are subsequently installed in the groove 201, the components can be evenly dissipated. Among them, the adhesive layer 40 is a semi-cured sheet material made of a thin sheet material made of treated glass fiber cloth impregnated with resin glue and then heat-treated.

[0052] S133 : placing the heat dissipation layer 20 into the second notch, and placing the metal gasket 30 into the first notch and the groove 201 .

[0053] Specifically, the heat dissipation layer 20 is placed into the second notch, and the metal gasket 30 is placed into the first notch and the groove 201, and the positions of the heat dissipation layer 20 and the metal gasket 30 inside the substrate 10 are fixed to facilitate subsequent lamination of the circuit board.

[0054] S134: Laminating the substrate 10, the adhesive layer 40, the metal pad 30 and the heat dissipation layer 20 to form a circuit board.

[0055] Specifically, before laminating the substrate 10 and the adhesive layer 40, the copper layer 50 on the surface of the substrate 10 can be physically roughened or chemically roughened, for example, using a physical method (such as abrasives such as corundum) or a chemical solution (micro-etching) to remove the surface oxide layer of the copper foil, creating micro-roughness, increasing the surface area, thereby improving the contact between subsequent substrates, thereby effectively ensuring the electrical performance, reliability, thermal stress resistance and processability of the circuit board. After the substrate 10 is roughened, the substrate 10 is cleaned to remove grease and impurities, thereby ensuring that there are no impurities remaining on the surface of the copper layer 50 of the substrate 10, preventing inclusions between the layers of the substrate 10 from affecting the lamination quality when the laminated substrate 10 and the adhesive layer 40 are laminated.

[0056] like Figure 3 As shown, Figure 3 for Figure 2 The schematic diagram of the cross-sectional structure of the circuit board after step S134 is completed, the circuit board includes a substrate 10, an adhesive layer 40, a metal gasket 30 and a heat dissipation layer 20. The position where the components need to be installed is set to the metal gasket 30, the metal gasket 30 is arranged in the groove 201 of the heat dissipation layer 20 and the first notch formed by the substrate 10 and the adhesive layer 40, and the heat dissipation layer 20 is arranged in the second notch.

[0057] Based on the general inventive concept, the present application also provides a circuit board, wherein the circuit board is obtained by the method for preparing a circuit board as described in any one of the above items.

[0058] Different from the prior art, the method for preparing a circuit board in the present application includes: obtaining a substrate 10, on which a heat dissipation layer 20 with a groove 201 is provided, a metal gasket 30 is provided in the groove 201, and then the substrate 10, the heat dissipation layer 20 and the metal gasket 30 are laminated to form a circuit board. The circuit board is subjected to copper electroplating, and etching is performed on the side of the circuit board away from the heat dissipation layer 20 to expose the metal gasket 30, and then the metal gasket 30 is taken out from the groove 201. By laminating the heat dissipation layer 20 into the circuit board through the metal gasket 30, it is effectively prevented that blistering is easy to occur during electroplating and that the exposed groove has a notch exposed substrate due to uneven force on the scraping line after the resin plugging hole, thereby ensuring the reliability of the product.

[0059] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a circuit board, characterized in that: The method for preparing the circuit board comprises: Obtain a substrate, on which a heat dissipation layer with grooves is disposed; Disposing a metal gasket in the groove; laminating the substrate, the heat dissipation layer and the metal pad to form a circuit board; The circuit board is subjected to copper electroplating; Etching the side of the circuit board away from the heat dissipation layer to expose the metal pad; The metal gasket is removed from the groove.

2. The method for preparing a circuit board according to claim 1, characterized in that: The step of laminating the substrate, the heat dissipation layer and the metal pad to form a circuit board comprises: Processing a first notch matching the groove at corresponding positions of the substrate and the adhesive layer, and processing a second notch communicating with the first notch at corresponding positions of the substrate and the adhesive layer; stacking the substrate and the adhesive layer in sequence; Put the heat dissipation layer into the second notch, and put the metal gasket into the first notch and the groove; The substrate, the adhesive layer, the metal pad and the heat dissipation layer are laminated to form a circuit board.

3. The method for preparing a circuit board according to claim 1, characterized in that: Before the step of laminating the substrate, the heat dissipation layer and the metal gasket to form a circuit board, the step further includes: Drilling one end of the metal gasket to form at least one blind hole; The end of the metal gasket with the blind hole is arranged away from the heat dissipation layer.

4. The method for preparing a circuit board according to claim 1, characterized in that: Before the step of laminating the substrate, the heat dissipation layer and the metal gasket to form a circuit board, the step further includes: A release agent is sprayed on the surface of the metal gasket.

5. The method for preparing a circuit board according to claim 1, characterized in that: The step of copper plating the circuit board comprises: The conductive holes on the circuit board are plugged with resin; The resin on the surface of the circuit board is leveled and excess resin is removed.

6. The method for preparing a circuit board according to claim 2, characterized in that: The size of the first notch is larger than the size of the groove, and after lamination, the sum of the depth of the first notch and the groove is the same as the thickness of the metal gasket.

7. The method for preparing a circuit board according to claim 1, characterized in that: The heat dissipation layer is made of ceramic or diamond copper material.

8. The method for preparing a circuit board according to claim 2, characterized in that: The adhesive layer is a prepreg material.

9. The method for preparing a circuit board according to claim 2, characterized in that: The metal gasket can be made of copper or aluminum.

10. A circuit board, characterized in that: The circuit board is prepared by the method for preparing a circuit board as described in any one of claims 1 to 9.

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