Copper block embedded PCB (printed circuit board) and manufacturing method thereof

Abstract

The invention provides a copper block embedded PCB (Printed Circuit Board) and a manufacturing method thereof. The PCB embedded with the copper block comprises a core board stacking body and the copper block, and a groove is formed in the core board stacking body and used for containing the copper block; the depth of the groove is smaller than or equal to the thickness of the copper block, and the difference value is 0-0.05 mm; a gap exists between the inner side wall of the groove and the copper block, and the width of the gap is smaller than or equal to 0.1 mm. According to the invention, the depth of the groove on the core board stacking body is limited to be less than or equal to the thickness of the copper block, and the difference value is 0-0.05 mm, so that the problems of delamination or copper block depression and the like can be prevented, and the flatness requirement of the PCB embedded with the copper block is ensured; meanwhile, a gap with the width smaller than or equal to 0.1 mm exists between the inner side wall of the groove and the copper block, and the displacement linetype of the copper block in the groove is avoided. According to the PCB embedded with the copper blocks, the copper blocks and the core board stacked body are high in binding force, good in product quality and high in qualified rate.

Description

Technical Field

[0001] The invention belongs to the technical field of printed circuit board production, and in particular relates to a PCB board with embedded copper blocks and a manufacturing method thereof. Background Art

[0002] With the continuous development of electronic information, the size of electronic products is getting smaller and smaller, the layout of devices is getting denser and denser, and the power of electronic components such as high frequency, radio frequency and power amplifier is getting higher and higher, resulting in higher and higher requirements for the heat dissipation performance of printed circuit boards. Later, the industry solved this problem by embedding copper blocks in printed circuit boards (PCBs). This type of printed circuit board is called an embedded copper block printed circuit board. The embedded copper block printed circuit board has the characteristics of high thermal conductivity, high heat dissipation, and saving board space. By embedding copper blocks, high-power electronic components can conduct heat through the copper blocks, ensuring the reliability and service life of the circuit board.

[0003] However, the current copper block embedding technology has the following problems: 1) The thickness of the copper block is difficult to determine, which may lead to problems such as delamination due to pressure loss or copper block depression; 2) The size of the gap between the copper block and the blind slot is difficult to control. The above problems lead to problems such as low product qualification rate of embedded copper block PCB boards.

[0004] Therefore, there is an urgent need to provide a new type of embedded copper block technology, which can not only prevent problems such as pressure loss stratification or copper block depression, but also accurately control the gap between the copper block and the blind slot to improve the product qualification rate. Summary of the invention

[0005] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a PCB board with embedded copper blocks and a method for manufacturing the same. The present invention limits the depth of the groove on the core board stack to be less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, which can prevent problems such as delamination due to pressure loss or depression of the copper block, and ensure the flatness requirements of the PCB board with embedded copper blocks; at the same time, there is a gap with a width of less than or equal to 0.1mm between the inner wall of the groove and the copper block, which avoids the displacement line of the copper block in the groove. In the embedded copper block PCB board of this structure, the copper block and the core board stack have strong bonding force, good product quality, and high qualified rate.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a copper block embedded PCB board, the copper block embedded PCB board comprising a core board stack and a copper block, the core board stack is provided with a groove for accommodating the copper block;

[0008] The depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0-0.05 mm; there is a gap between the inner wall of the groove and the copper block, and the width of the gap is less than or equal to 0.1 mm.

[0009] The present invention limits the depth of the groove on the core board stack to be less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, which can prevent problems such as delamination due to pressure loss or copper block depression, and ensure the flatness requirements of the PCB board embedded with copper blocks; at the same time, there is a gap with a width of less than or equal to 0.1mm between the inner side wall of the groove and the copper block, which avoids the displacement line of the copper block in the groove. The copper block and the core board stack in the embedded copper block PCB board of this structure have strong bonding force, good product quality, and high qualified rate.

[0010] Preferably, the core plate stack includes a first core plate component, a prepreg sheet and a second core plate component sequentially arranged along a height direction of the core plate stack, and the groove runs through the prepreg sheet and the first core plate component.

[0011] Preferably, the first core plate member includes a first core plate layer and a first copper layer disposed on both side surfaces of the first core plate layer.

[0012] Preferably, the material of the prepreg includes epoxy resin and glass fiber cloth.

[0013] Preferably, the second core plate member includes a second core plate layer and second copper layers arranged on both side surfaces of the second core plate layer.

[0014] Preferably, the gap is filled with adhesive.

[0015] Preferably, the adhesive comprises the prepreg.

[0016] Preferably, the embedded copper block PCB board further includes an adhesive resistance film, and the adhesive resistance film is pressed onto a side surface of the core board stack having the groove.

[0017] In a second aspect, the present invention provides a method for manufacturing a PCB board with embedded copper blocks as described in the first aspect, the manufacturing method comprising the following steps:

[0018] A core plate stack having a groove and a copper block are obtained, and the copper block is buried in the groove.

[0019] The copper block is pressed and fixed so that the depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, and there is a gap between the inner wall of the groove and the copper block, and the width of the gap is less than or equal to 0.1mm.

[0020] After the core plate stacking body with the grooves is obtained, the copper blocks are embedded, which helps to place the copper blocks stably.

[0021] Preferably, the method for preparing the core plate stack includes:

[0022] A first core board component is provided, wherein the first core board component comprises a first core board layer and a first copper layer arranged on both side surfaces of the first core board layer, and the first core board component is milled and windowed.

[0023] Mill grooves and open windows on the prepreg.

[0024] The first core plate component after milling and windowing, the dry cured sheet after milling and windowing, and the second core plate component are stacked and pressed to form grooves, and then post-processed to obtain the core plate stack.

[0025] Preferably, the copper block pretreatment method comprises: cutting and milling the copper block raw material.

[0026] Preferably, after the copper block is milled, it is also subjected to browning treatment.

[0027] Preferably, before the copper block is pressed and fixed, a layer of adhesive resistance film is firstly covered on the surface of one side of the core board stack having the groove.

[0028] Preferably, after the lamination, a debonding process is also performed.

[0029] Preferably, the production method comprises the following steps:

[0030] (1) A first core plate component is provided, wherein the first core plate component includes a first core plate layer and a first copper layer disposed on both side surfaces of the first core plate layer, and the first core plate component is milled and windowed to obtain a first core plate component after milling and windowing.

[0031] The prepreg is milled and windowed to obtain a prepreg after milling and windowing.

[0032] The first core plate component after milling and windowing, the dry cured sheet after milling and windowing, and the second core plate component are stacked and pressed to form grooves, and then post-processed to obtain the core plate stack.

[0033] (2) The copper block is cut, milled and browned to obtain a pretreated copper block.

[0034] (3) The pretreated copper block is buried in the groove of the core board stack, and then a layer of adhesive resistance film is covered on the surface of one side of the core board stack with the groove, and then the copper block is pressed and fixed. After pressing, the glue overflow at the copper block is checked, and the glue overflow is manually polished off so that the depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, there is a gap between the inner wall of the groove and the copper block, and the width of the gap is less than or equal to 0.1mm, and the gap is filled with adhesive, and the adhesive includes the semi-cured sheet.

[0035] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention limits the depth of the groove on the core board stack to be less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, which can prevent problems such as delamination due to pressure loss or copper block depression, and ensure the flatness requirements of the PCB board embedded with copper blocks; at the same time, there is a gap with a width of less than or equal to 0.1mm between the inner side wall of the groove and the copper block, which avoids the displacement line of the copper block in the groove. The copper block and the core board stack in the embedded copper block PCB board of this structure have strong bonding force, good product quality, and high qualified rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of a partial structure of a copper-embedded PCB board provided in a specific embodiment of the present invention.

[0039] Among them, 1-first core board component; 11-first core board layer; 12-first copper layer; 2-prepreg sheet; 3-second core board component; 31-second core board layer; 32-second copper layer; 4-copper block. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0041] In a specific embodiment, the present invention provides a PCB board with embedded copper blocks, a partial structural schematic diagram of which is shown in FIG. Figure 1As shown, the embedded copper block PCB board includes a core board stack and a copper block 4, and the core board stack is provided with a groove for accommodating the copper block 4; the depth of the groove is less than or equal to the thickness of the copper block 4, and the difference is 0-0.05mm; there is a gap between the inner wall of the groove and the copper block 4, and the width of the gap is less than or equal to 0.1mm.

[0042] In the present invention, the difference between the depth of the groove and the thickness of the copper block 4 is 0-0.05mm, for example, it can be 0.01mm, 0.02mm, 0.03mm, 0.04mm or 0.05mm. The width of the gap is less than or equal to 0.1mm, for example, it can be 0.1mm, 0.08mm, 0.06mm, 0.04mm, 0.02mm or 0.01mm. Through the above definition, problems such as pressure loss delamination or copper block 4 depression can be prevented, and the flatness requirements of the embedded copper block PCB board can be guaranteed; at the same time, the displacement line of the copper block 4 in the groove is avoided. In the embedded copper block PCB board of this structure, the copper block 4 has a strong bonding force with the core board stacking body, has good product quality, and has a high pass rate.

[0043] Specifically, the core plate stack includes a first core plate component 1 , a prepreg 2 , and a second core plate component 3 arranged in sequence along a height direction of the core plate stack, and the groove runs through the prepreg 2 and the first core plate component 1 .

[0044] Specifically, the first core plate member 1 includes a first core plate layer 11 and first copper layers 12 arranged on both side surfaces of the first core plate layer 11 .

[0045] It should be noted that, according to actual needs, suitable materials can be selected as the first core plate layer, such as common thermosetting resins such as epoxy resin and phenolic resin, which are compounded with reinforcing materials such as glass fiber cloth.

[0046] It should be noted that, in the core board stack, the first copper layer 12 away from the second core board component 3 has a circuit pattern.

[0047] Specifically, the material of the prepreg 2 includes epoxy resin and glass fiber cloth.

[0048] It should be noted that fiberglass cloth refers to glass fiber cloth.

[0049] Specifically, the second core plate member 3 includes a second core plate layer 31 and second copper layers 21 arranged on both side surfaces of the second core plate layer 31 .

[0050] It should be noted that, in the core board stack, the second copper layer 21 away from the first core board member 1 has a circuit pattern.

[0051] Specifically, the gap is filled with adhesive.

[0052] Specifically, the adhesive includes the prepreg 2 .

[0053] It should be noted that during the lamination process, the viscosity of the semi-cured sheet 2 decreases and it flows into the gap to fill it. After the lamination is completed, it solidifies and fixes the copper block 4. After filling the gap, it can prevent the medicine from being hidden in the gap, polluting the medicine tank or attacking the side wall of the copper block.

[0054] Specifically, the embedded copper block PCB board also includes an adhesive resistance film, and the adhesive resistance film is pressed on the side surface of the core board stack having the groove.

[0055] It should be noted that the present invention does not limit the material selection of the adhesive resistance film. For example, a commercial adhesive resistance film may be used, such as the adhesive resistance film model XM50PL produced by Yixin Material Technology Co., Ltd. This adhesive resistance film can effectively reduce the overflow of adhesive around the copper block after lamination.

[0056] In another specific embodiment, the present invention provides a method for manufacturing a PCB board with embedded copper blocks, the manufacturing method comprising the following steps:

[0057] (1) A first core board component is provided, wherein the first core board component includes a first core board layer and a first copper layer arranged on both side surfaces of the first core board layer, and the first core board component is milled and windowed to obtain a first core board component after milling and windowing.

[0058] The prepreg is milled and windowed to obtain a prepreg after milling and windowing.

[0059] The first core plate component after milling and windowing, the dry cured sheet after milling and windowing, and the second core plate component are stacked and pressed to form grooves, and then post-processed to obtain the core plate stack.

[0060] (2) The copper block is cut, milled and browned to obtain a pretreated copper block.

[0061] (3) The pretreated copper block is buried in the groove of the core board stack, and then a layer of adhesive resistance film is covered on the surface of one side of the core board stack with the groove, and then the copper block is pressed and fixed. After pressing, the glue overflow at the copper block is checked, and the glue overflow is manually polished off so that the depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, there is a gap between the inner wall of the groove and the copper block, and the width of the gap is less than or equal to 0.1mm, and the gap is filled with adhesive, and the adhesive includes the semi-cured sheet.

[0062] It should be noted that before stacking the prepregs, the first core board is first cut, the copper layer is patterned and acid-etched. Before stacking and laminating the second core board, it is first cut, the copper layer is patterned and acid-etched.

[0063] It should be noted that after the first core plate is milled and the windows are opened, rivet holes are punched, browning and riveting are performed.

[0064] Specifically, the post-processing steps include milling, drilling, copper plating, full-board electroplating, resin plugging, secondary drilling, copper plating, full-board electroplating, outer layer patterning, pattern electroplating, outer layer alkaline etching, solder mask silk screen printing, solder mask exposure, solder mask development, solder mask inspection, character printing, solder mask post-curing, chemical nickel gold, surface treatment inspection, flying probe test and molding.

[0065] It should be noted that after the resin plugging, check whether there is a gap between the copper block and the first core board at the copper block position, and use manual polishing to smooth the residual resin gap between the copper block and the core board; outer layer graphics refers to the design of the outer layer circuit graphics of the second copper layer on both sides of the second core board according to requirements; the purpose of flying probe test is to test the connectivity and insulation of the embedded copper block PCB board.

[0066] Example 1

[0067] The present embodiment provides an embedded copper block PCB board, which includes a core board stack and a copper block. The core board stack is provided with a groove for accommodating the copper block; the depth of the groove is equal to the thickness of the copper block; there is a gap between the inner side wall of the groove and the copper block, and the width of the gap is 0.05 mm.

[0068] The core panel stack includes a first core panel component, a semi-cured sheet and a second core panel component arranged in sequence along the height direction of the core panel stack, and the groove runs through the semi-cured sheet and the first core panel component; the first core panel component includes a first core panel layer and a first copper layer arranged on both side surfaces of the first core panel layer, and the material of the first core panel layer is composed of a composite of epoxy resin and glass fiber cloth; the material of the semi-cured sheet is composed of epoxy resin and glass fiber cloth; the second core panel component includes a second core panel layer and a second copper layer arranged on both side surfaces of the second core panel layer, and the material of the second core panel layer is composed of epoxy resin and glass fiber cloth; the gap is filled with an adhesive, and the adhesive includes the semi-cured sheet and a resin.

[0069] The embedded copper block PCB board also includes a resist film (model: XM50PL), and the resist film is pressed onto a side surface of the core board stack having a groove.

[0070] This embodiment also provides a method for preparing the above-mentioned embedded copper block PCB board, and the manufacturing method comprises the following steps:

[0071] (1) Providing a first core board component, wherein the first core board component includes a first core board layer and a copper layer disposed on both side surfaces of the first core board layer, cutting the first core board component, patterning the copper layer, and acid etching the copper layer, and performing automatic optical inspection (AOI) on the first core board component.

[0072] The first core plate is subjected to milling and windowing to obtain a first core plate after milling and windowing.

[0073] The prepreg is milled and windowed to obtain a prepreg after milling and windowing.

[0074] The first core board after milling grooves and windows, the dry cured sheet after milling grooves and windows, and the second core board after milling grooves and windows are stacked and pressed to form grooves, and then milling edges, drilling, copper plating, full-board electroplating, resin plugging, secondary drilling, copper plating, full-board electroplating, outer layer graphicization, graphic electroplating, outer layer alkaline etching, solder mask silk screen printing, solder mask exposure, solder mask development, solder mask inspection, character printing, solder mask post-curing, chemical nickel gold, surface treatment inspection, flying probe test and molding are carried out in sequence to obtain the core board stack.

[0075] (2) The copper block is cut, milled and browned to obtain a pretreated copper block.

[0076] (3) The pretreated copper block is buried in the groove of the core board stack, and then a layer of adhesive resistance film is covered on the surface of one side of the core board stack with the groove, and then the copper block is pressed and fixed. After pressing, the glue overflow at the copper block is checked, and the glue overflow is manually polished off so that the depth of the groove is equal to the thickness of the copper block, and there is a gap between the inner wall of the groove and the copper block, and the width of the gap is 0.05mm. The gap is filled with adhesive, and the adhesive is the semi-cured sheet.

[0077] Example 2

[0078] The present embodiment provides a PCB board with embedded copper blocks, which includes a core board stack and a copper block. The core board stack is provided with a groove for accommodating the copper block. The depth of the groove is less than the thickness of the copper block, and the difference is 0.05 mm. There is a gap between the inner side wall of the groove and the copper block, and the width of the gap is equal to 0.1 mm.

[0079] The core panel stack includes a first core panel component, a semi-cured sheet and a second core panel component arranged in sequence along the height direction of the core panel stack, and the groove runs through the semi-cured sheet and the first core panel component; the first core panel component includes a first core panel layer and a first copper layer arranged on both side surfaces of the first core panel layer, and the material of the first core panel layer is composed of a composite of epoxy resin and glass fiber cloth; the material of the semi-cured sheet is composed of epoxy resin and glass fiber cloth; the second core panel component includes a second core panel layer and a second copper layer arranged on both side surfaces of the second core panel layer, and the material of the second core panel layer is composed of epoxy resin and glass fiber cloth; the gap is filled with an adhesive, and the adhesive includes the semi-cured sheet and a resin.

[0080] The embedded copper block PCB board also includes a resist film (model: XM50PL), and the resist film is pressed onto a side surface of the core board stack having a groove.

[0081] This embodiment also provides a method for preparing the above-mentioned embedded copper block PCB board, and the manufacturing method comprises the following steps:

[0082] (1) A first core board component is provided, wherein the first core board component includes a first core board layer and a copper layer disposed on both side surfaces of the first core board layer, and the first core board component is cut, the copper layer is patterned and acid-etched, and an automatic optical inspection (AOI) is performed.

[0083] The first core plate is subjected to milling and windowing to obtain a first core plate after milling and windowing.

[0084] The prepreg is milled and windowed to obtain a prepreg after milling and windowing.

[0085] The first core board after milling grooves and windows, the dry cured sheet after milling grooves and windows, and the second core board after milling grooves and windows are stacked and pressed to form grooves, and then milling edges, drilling, copper plating, full-board electroplating, resin plugging, secondary drilling, copper plating, full-board electroplating, outer layer graphicization, graphic electroplating, outer layer alkaline etching, solder mask silk screen printing, solder mask exposure, solder mask development, solder mask inspection, character printing, solder mask post-curing, chemical nickel gold, surface treatment inspection, flying probe test and molding are carried out in sequence to obtain the core board stack.

[0086] (2) The copper block is cut, milled and browned to obtain a pretreated copper block.

[0087] (3) The pretreated copper block is buried in the groove of the core board stack, and then a layer of adhesive resistance film is covered on the surface of one side of the core board stack with the groove, and then the copper block is pressed and fixed. After pressing, the glue overflow at the copper block is checked, and the glue overflow is manually polished off so that the depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0.05mm. There is a gap between the inner wall of the groove and the copper block, and the width of the gap is equal to 0.1mm. The gap is filled with adhesive, and the adhesive is the semi-cured sheet.

[0088] Based on the technical solutions provided in the above-mentioned embodiments 1 and 2, the embedded copper block PCB board designed in the present invention can prevent problems such as pressure loss delamination or copper block depression, and can accurately control the gap between the copper block and the groove, thereby improving the product qualification rate, and has good market application prospects and good process performance.

[0089] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A PCB board with embedded copper blocks, characterized in that: The copper block embedded PCB board comprises a core board stack and a copper block, and a groove is formed on the core board stack for accommodating the copper block; The depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0-0.05 mm; there is a gap between the inner wall of the groove and the copper block, and the width of the gap is less than or equal to 0.1 mm.

2. The embedded copper block PCB board according to claim 1, characterized in that: The core plate stack body comprises a first core plate component, a prepreg sheet and a second core plate component which are sequentially arranged along the height direction of the core plate stack body, and the groove passes through the prepreg sheet and the first core plate component; Preferably, the first core plate member comprises a first core plate layer and a first copper layer arranged on both side surfaces of the first core plate layer; Preferably, the material of the prepreg comprises epoxy resin and glass fiber cloth; Preferably, the second core plate member includes a second core plate layer and second copper layers arranged on both side surfaces of the second core plate layer.

3. The embedded copper block PCB board according to claim 1 or 2, characterized in that: The gap is filled with adhesive; Preferably, the adhesive comprises the prepreg.

4. The embedded copper block PCB board according to any one of claims 1 to 3, characterized in that: The embedded copper block PCB board also includes an adhesive resistance film, and the adhesive resistance film is pressed on a side surface of the core board stack having a groove.

5. A method for manufacturing a PCB board with embedded copper blocks as claimed in any one of claims 1 to 4, characterized in that: The production method comprises the following steps: Obtaining a core plate stack having a groove and a copper block, and burying the copper block in the groove; The copper block is pressed and fixed so that the depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, and there is a gap between the inner wall of the groove and the copper block, and the width of the gap is less than or equal to 0.1mm.

6. The method according to claim 5, characterized in that: The method for preparing the core plate stack comprises: Providing a first core plate component, the first core plate component comprising a first core plate layer and a first copper layer arranged on both side surfaces of the first core plate layer, and performing milling and windowing on the first core plate component; Milling grooves and opening windows on the prepreg; The first core plate component after milling and windowing, the dry cured sheet after milling and windowing, and the second core plate component are stacked and pressed to form grooves, and then post-processed to obtain the core plate stack.

7. The production method according to claim 5 or 6, characterized in that: The copper block pretreatment method comprises: cutting and milling the copper block raw material.

8. The production method according to any one of claims 5 to 7, characterized in that: Before the copper block is pressed and fixed, a layer of adhesive resistance film is firstly covered on the surface of one side of the core plate stack having the groove; Preferably, after the lamination, a debonding process is also performed.

9. The production method according to any one of claims 5 to 8, characterized in that: The production method comprises the following steps: (1) providing a first core plate component, the first core plate component comprising a first core plate layer and a first copper layer disposed on both side surfaces of the first core plate layer, and performing milling and windowing on the first core plate component to obtain a first core plate component after milling and windowing; Milling and windowing the prepreg to obtain a milled and windowed prepreg; The first core plate after milling and windowing, the dry cured sheet after milling and windowing, and the second core plate are stacked and pressed to form a groove, and then post-processed to obtain the core plate stacked body; (2) cutting, milling and browning the copper block to obtain a pretreated copper block; (3) The pretreated copper block is embedded in the groove of the core board stack, and then a layer of adhesive resistance film is covered on the surface of one side of the core board stack with the groove, and then the copper block is pressed and fixed. After pressing, the glue overflow at the copper block is checked, and the glue overflow is manually polished off so that the depth of the groove is less than or equal to the thickness of the copper block, and the difference is 0-0.05mm, there is a gap between the inner wall of the groove and the copper block, and the width of the gap is less than or equal to 0.1mm, and the gap is filled with adhesive, and the adhesive includes the semi-cured sheet.

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