Method for improving poor board explosion of copper-embedded product

Abstract

The invention discloses a method for improving poor board explosion of a copper-embedded product, which belongs to the technical field of improvement of the copper-embedded product, and comprises the following steps during manufacturing of an inner layer in a circuit board manufacturing process: not avoiding copper at a copper block on a Top surface / Bottom surface of a board during exposure of a negative film, and retaining base material copper at the copper block during etching; when the outer layer is manufactured in the manufacturing process of the circuit board, the following operation is carried out: one or more bonding pad type heat dissipation windows are etched on the periphery of an outer layer copper block. According to the invention, copper is not avoided at the copper block, the base material copper is reserved, and the bonding pad type heat dissipation window is additionally arranged around the copper block, so that the binding force of the copper-embedded product is increased, the copper-embedded product can stably dissipate heat towards four sides when passing through high temperature, and the phenomenon that no outward heat dissipation position exists in the high-temperature process is avoided; and the phenomenon of board explosion and separation of a copper-plated layer between the position of the copper block and the mainboard of the copper-embedded product is avoided.

Description

Technical Field

[0001] The invention relates to a method for improving the defect of bursting of embedded copper products, belonging to the technical field of improvement of embedded copper products. Background Art

[0002] In PCB process design, there is a type of wireless power amplifier product that needs to use the copper block embedding process. The copper block is fixed in the PCB by the press-fitting flow glue during pressing, and then connected to the PCB by electroplating copper. During the PCB processing and customer loading process, it needs to go through multiple high-temperature stations. Since the copper block has a large thermal coefficient, it is heated faster than the PCB substrate area. Especially when passing through high-temperature soldering, the stress of the copper block's thermal expansion is greater than the stress of the PCB substrate area, which will cause a large stress on the copper plating at the connection between the copper block and the PCB, causing the copper plating layer at the connection between the copper block and the PCB to bulge and delaminate, resulting in poor reliability. At present, the existing technology has no good method to improve the edge burst of the copper block of the embedded copper product, which has a great impact on the product quality. Summary of the invention

[0003] The purpose of the present invention is to provide a method for improving the defect of plate bursting of embedded copper products, thereby improving the defect of plate bursting of embedded copper products.

[0004] To achieve the above objectives, the present invention is implemented by adopting the following technical solutions: The present invention provides a method for improving the problem of plate bursting of embedded copper products, comprising: The following operations are performed when making the inner layer of the circuit board: when exposing the film, copper is not avoided at the copper block on the top / bottom side of the board, and the base copper at the copper block is retained during etching; When making the outer layer during the circuit board manufacturing process, the following operations are performed: one or more heat dissipation windows in the form of solder pads are etched around the outer copper block.

[0005] Furthermore, the etching position of the heat dissipation window is the position of the via hole or the position of the slot hole.

[0006] Furthermore, the heat dissipation window in the form of a solder pad is two circular heat dissipation windows of different sizes connected to each other.

[0007] Furthermore, the center positions of the two circular heat dissipation windows of different sizes are the same.

[0008] Furthermore, the center position of the circle is the center of the via hole or the center of the slot hole.

[0009] Furthermore, the heat dissipation window in the form of a solder pad also includes a plurality of copper bridges, and the plurality of copper bridges connect two circular heat dissipation windows of different sizes.

[0010] Furthermore, the plurality of copper bridges are symmetrical in the up-down direction.

[0011] Furthermore, the plurality of copper bridges are symmetrical in the left-right direction.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are: The present invention provides a method for improving the poor board bursting of embedded copper products. The method does not avoid copper at the copper block, retains the base copper, and adds heat dissipation windows in the form of solder pads around the copper block. This not only increases the bonding strength of the embedded copper product, but also allows the embedded copper product to stably dissipate heat to all sides when subjected to high temperature, thereby avoiding the lack of outward heat dissipation position during the high temperature process and avoiding the copper block position and the embedded copper product mainboard to cause the copper plating layer to burst and separate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a flow chart of a method for improving the defect of buried copper product bursting provided by an embodiment of the present invention; Figure 2 is a cross-sectional view of an embedded copper product in the prior art provided by an embodiment of the present invention; Figure 3 is a schematic diagram of a heat dissipation window in the form of a solder pad provided in an embodiment of the present invention; Figure 4 is a plan view of an embedded copper product manufactured by the method of the present invention provided by an embodiment of the present invention; Figure 5 It is a cross-sectional view of an embedded copper product manufactured by the method of the present invention provided by an embodiment of the present invention.

[0014] In the figure: 1. Copper block; 2. Resin; 3. Substrate core; 4. Electroplated copper; 5. PCB; 6. Heat dissipation window. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0016] Example 1.

[0017] like Figure 1 As shown, the present invention provides a method for improving the problem of plate bursting of embedded copper products, comprising: The following operations are performed when making the inner layer of the circuit board: when exposing the film, copper is not avoided at the copper block on the top / bottom side of the board, and the base copper at the copper block is retained during etching; When making the outer layer during the circuit board manufacturing process, the following operations are performed: one or more heat dissipation windows in the form of solder pads are etched around the outer copper block.

[0018] The present invention does not avoid copper at the copper block, retains the base copper, and adds heat dissipation windows in the form of solder pads around the copper block, thereby increasing the bonding strength of the embedded copper product and allowing the embedded copper product to stably dissipate heat to all sides when subjected to high temperature, thereby avoiding the lack of outward heat dissipation position during the high temperature process and avoiding the copper block position and the embedded copper product mainboard to cause the copper plating layer to explode and separate.

[0019] Example 2.

[0020] The circuit board production process in the prior art is as follows: cutting (cutting the supplier's substrate into the pre-designed size of the product), making the inner layer (etching out the inner layer circuits and graphics through coating, exposure, development, etching, and degumming), forming (fishing out the copper block position), pressing (pressing multiple Core layers into a PCB board after browning, and putting the copper block into the pressing), drilling (drilling the holes required by the customer with a drill), copper plating (copper-plating the through holes to form the current conduction circuit required by the customer), making the outer layer (etching out the outer layer circuits and graphics through lamination, exposure, development, etching, and degumming), and subsequent processes.

[0021] Core is the core board.

[0022] like Figure 2 As shown, there is a problem of board explosion in the prior art, the copper block 1 is embedded inside the embedded copper product, the resin 2 is distributed between the substrate Core 3, and the electroplated copper 4 is on the outermost layer.

[0023] The present invention provides a method for improving the problem of plate bursting of embedded copper products, which improves the steps of making an inner layer and making an outer layer in the prior art. The specific implementation includes the following steps: The following operations are performed when making the inner layer of the circuit board: when exposing the film, do not avoid copper at the copper block on the top / bottom side of the board, and retain the base copper at the copper block during etching to avoid direct connection between the base and the electroplated copper and increase the bonding strength; When making the outer layer during the circuit board manufacturing process, the following operations are performed: one or more heat dissipation windows in the form of thermal pads are etched around the outer copper block.

[0024] The heat dissipation window is usually located at the via hole (through hole) or slot hole position. The heat dissipation window is two circular rings of different sizes, such as Figure 3As shown, the diameter of the large ring is R mil, mil is milliinch, and the diameter of the small ring is r mil. The center positions of the small ring and the large ring are consistent, and the center positions are both the center of the via hole (through hole) or the slot hole. Copper bridges are designed to connect the top, bottom, left and right centers. There is a distance between the heat dissipation windows, and there is also a distance between the heat dissipation windows and the copper block. The number of heat dissipation windows varies with the size of the copper block. The larger the copper block, the more heat dissipation windows are required. Copper is not avoided at the copper block, and the substrate copper is retained to increase the PCB bonding strength at the copper block. Then, part of the substrate copper skin around the copper block is removed through the heat dissipation window in the form of a thermal pad, so that the stress generated by the expansion of the copper block after heating can be released through the substrate here, instead of the full copper design, where the stress cannot be discharged and the copper plating layer at the connection between the copper block and the PCB is lifted, causing the PCB to explode.

[0025] like Figure 4 As shown, the heat dissipation windows 6 are distributed around the copper block 1 on the PCB board 5, as shown in FIG. Figure 5 As shown, the copper block 1 is embedded in the embedded copper product, the resin 2 is distributed between the substrate core 3, the electroplated copper 4 is on the outermost layer, and the heat dissipation windows 6 are distributed around the copper block 1.

[0026] By changing the shape of the outermost large copper surface, etching away a portion of the copper, and forming a heat dissipation window in the form of a thermal pad on the via hole, it will not cause the outer layer line to open short circuit, so it will not affect the customer's final PCB functionality.

[0027] If there are fewer via holes designed around the copper block, customers can be advised to appropriately increase the via holes and thermal pads. This will not increase the process cost and can effectively reduce the risk of board explosion during soldering.

[0028] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for improving the problem of plate bursting of embedded copper products, characterized in that: include: The following operations are performed when making the inner layer of the circuit board: when exposing the film, copper is not avoided at the copper block on the top / bottom side of the board, and the base copper at the copper block is retained during etching; When making the outer layer during the circuit board manufacturing process, the following operations are performed: one or more heat dissipation windows in the form of solder pads are etched around the outer copper block.

2. The method for improving the defect of embedded copper product bursting according to claim 1, characterized in that: The etching position of the heat dissipation window is the position where the via hole is located or the position where the slot hole is located.

3. The method for improving the defect of embedded copper product bursting according to claim 1, characterized in that: The heat dissipation window in the form of a soldering pad is two circular heat dissipation windows of different sizes connected to each other.

4. The method for improving the problem of buried copper product bursting according to claim 3, characterized in that: The center positions of the two circular heat dissipation windows of different sizes are the same.

5. The method for improving the defect of embedded copper product bursting according to claim 4, characterized in that: The center position of the circle is the center of the via hole or the center of the slot hole.

6. The method for improving the defect of embedded copper product bursting according to claim 3, characterized in that: The heat dissipation window in the form of a solder pad also includes a plurality of copper bridges, and the plurality of copper bridges connect two circular heat dissipation windows of different sizes.

7. The method for improving the defect of embedded copper product bursting according to claim 6, characterized in that: The plurality of copper bridges are symmetrical in the up-down direction.

8. The method for improving the defect of embedded copper product bursting according to claim 6, characterized in that: The plurality of copper bridges are symmetrical in the left-right direction.

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