Circuit board and method of manufacturing the same

Abstract

The application provides a circuit board, which comprises a core board, a first circuit substrate and a second circuit substrate. The first circuit substrate and the second circuit substrate are arranged on opposite sides of the core board respectively. The core board comprises a substrate layer, a first inner side circuit layer, a second inner side circuit layer and a plurality of conductive structures. The first inner side circuit layer and the second inner side circuit layer are arranged on opposite sides of the substrate layer respectively. The inner side conductive structures are arranged in the substrate layer. The inner side conductive structures are electrically connected to the first inner side circuit layer and the second inner side circuit layer. The inner side conductive structures comprise conductive paste. The first inner side circuit layer is electrically connected to the first circuit substrate. The second inner side circuit layer is electrically connected to the second circuit substrate. In addition, the application further provides a manufacturing method of the circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to a circuit board and a manufacturing method thereof. BACKGROUND

[0002] Generally, the high-frequency signal transmission circuit board includes multi-layer signal transmission lines, and each layer of the signal transmission lines is connected through a via hole. The via hole is divided into a solid conductive post and a hollow conductive tube. The solid conductive post is mainly formed by electroplating or electroless plating processing. The deposition rate of copper in the electroplating or electroless plating process is affected by various factors, such as copper ion concentration, temperature, current density, etc. The hollow conductive tube usually needs to be filled with insulating resin to avoid the problem of plate expansion during pressing. However, the adhesion between the insulating resin and the conductive pad is insufficient, and the heat dissipation is poor, which affects the final quality of the high-frequency signal transmission circuit board. SUMMARY

[0003] To solve the problems in the background art, the present application provides a manufacturing method of a circuit board.

[0004] In addition, it is necessary to provide a high-frequency circuit board.

[0005] A manufacturing method of a circuit board includes the following steps: providing a core board, the core board includes a substrate layer, a first inner side circuit layer, a second inner side circuit layer, and a plurality of conductive structures, the first inner side circuit layer and the second inner side circuit layer are respectively arranged on opposite sides of the substrate layer, the inner side conductive structure is arranged in the substrate layer, the inner side conductive structure is electrically connected to the first inner side circuit layer and the second inner side circuit layer, and the inner side conductive structure includes a conductive paste. A first circuit substrate is arranged on the first inner side circuit layer, the first circuit substrate is electrically connected to the first inner side circuit layer, and a second circuit substrate is arranged on the second inner side circuit layer, the second circuit substrate is electrically connected to the second inner side circuit layer, and the circuit board is obtained.

[0006] Further, the manufacturing method of the core board includes the following steps: providing a double-sided copper-clad substrate, the double-sided copper-clad substrate includes a substrate layer, a first copper foil layer, and a second copper foil layer, the first copper foil layer and the second copper foil layer are respectively arranged on opposite sides of the substrate layer, and the double-sided copper-clad substrate is provided with an opening, the opening penetrates through the first copper foil layer, the substrate layer, and the second copper foil layer.

[0007] A first electroplating layer is arranged on the first copper foil layer, and a second electroplating layer is arranged on the second copper foil layer, part of the first electroplating layer and part of the second electroplating layer are filled into the opening to form a hollow conductive body.

[0008] The conductive paste is arranged in the conductive body, and the first copper foil layer and the second electroplated layer are etched to form the first inner side circuit layer, and the second copper foil layer and the second electroplated layer are etched to form the second inner side circuit layer, thereby obtaining the core board.

[0009] Further, the conductive paste comprises an adhesive and a conductive powder, the adhesive comprises at least one of polyurethane resin, polyurethane rubber, acrylic resin, acrylic rubber, butyl rubber, chlorosulfonated rubber, fluororubber, and silicone, and the conductive powder comprises at least one of copper powder, gold powder, zinc powder, and graphite powder.

[0010] A circuit board comprises a core board, a first circuit substrate, and a second circuit substrate, the first circuit substrate and the second circuit substrate are arranged on opposite sides of the core board respectively. The core board comprises a substrate layer, a first inner side circuit layer, a second inner side circuit layer, and a plurality of conductive structures, the first inner side circuit layer and the second inner side circuit layer are arranged on opposite sides of the substrate layer respectively, the inner side conductive structures are arranged in the substrate layer, the inner side conductive structures are electrically connected to the first inner side circuit layer and the second inner side circuit layer, and the inner side conductive structures comprise a conductive paste. The first inner side circuit layer is electrically connected to the first circuit substrate, and the second inner side circuit layer is electrically connected to the second circuit substrate.

[0011] Further, the first inner side circuit layer and the second inner side circuit layer further comprise a plurality of positioning pads, and the positioning pads are arranged around the conductive structures.

[0012] Further, the inner side conductive structure further comprises a hollow conductive body, the substrate layer is provided with an opening, the conductive body is arranged in the opening, the conductive paste is arranged in the conductive body, and opposite ends of the conductive body are electrically connected to the first inner side circuit layer and the second inner side circuit layer.

[0013] Further, the first circuit substrate comprises a first dielectric layer, a first intermediate circuit layer, and a plurality of first intermediate conductive structures, the first dielectric layer is arranged on the first inner side circuit layer, the first intermediate circuit layer and the first intermediate conductive structures are arranged in the first dielectric layer, the first intermediate conductive structures are electrically connected between the first inner side circuit layer and the first intermediate circuit layer, and the first intermediate conductive structures correspond to the first inner side conductive structures.

[0014] Further, the first intermediate conductive structure comprises the conductive paste, the first intermediate circuit layer comprises a plurality of transmission lines, and in the thickness direction of the circuit board, the cross-sectional projection of the transmission lines is located in the conductive paste.

[0015] Further, the first circuit substrate further comprises a first outer circuit layer and a plurality of first outer conductive structures, the first outer circuit layer is arranged on a side of the first dielectric layer away from the first inner circuit layer, and the first outer conductive structures are arranged between the first intermediate circuit layer and the first outer circuit layer.

[0016] Further, the second circuit substrate comprises a second dielectric layer, a second outer circuit layer and a second outer conductive structure, the second dielectric layer is arranged on the second inner circuit layer, the second outer circuit layer is arranged on a side of the second dielectric layer away from the second inner circuit layer, and the second outer conductive structure electrically connects the second outer circuit layer and the second inner circuit layer.

[0017] The circuit board provided by the present application reduces the problems such as cavities and recesses that are prone to occur in the solid conductive pillars formed by electroplating or chemical plating by arranging the conductive paste in the core board to realize high-frequency signal transmission between layers, and the conductive paste has excellent combination ability with other materials and good heat conduction performance. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A schematic diagram of a double-sided copper-clad substrate provided by an embodiment of the present application.

[0019] Figure 2 A schematic diagram of the double-sided copper-clad substrate provided by the present application. Figure 1 A schematic diagram of the double-sided copper-clad substrate provided by the present application.

[0020] Figure 3 A schematic diagram of the double-sided copper-clad substrate provided by the present application. Figure 2 A schematic diagram of the double-sided copper-clad substrate provided by the present application.

[0021] Figure 4 A schematic diagram of a core board provided by an embodiment of the present application.

[0022] Figure 5 A schematic diagram of a high-frequency transmission circuit board provided by an embodiment of the present application.

[0023] Figure 6 A schematic diagram of an antenna module provided by an embodiment of the present application.

[0024] Figure 7 A schematic diagram of a core board provided by another embodiment of the present application.

[0025] MAIN ELEMENT SYMBOL EXPLANATION

[0026] High-frequency transmission circuit board 100

[0027] Core board 10, 10a

[0028] Base material layer 11

[0029] First inner side circuit layer 12

[0030] Second inner side circuit layer 13

[0031] Inner side conductive structure 14

[0032] Double-sided copper clad substrate 20

[0033] First copper foil layer 21

[0034] Second copper foil layer 22

[0035] Aperture 23

[0036] First electroplated layer 24

[0037] Second electroplated layer 25

[0038] Conductive paste 30

[0039] Positioning pad 31

[0040] Conductive body 32

[0041] First circuit substrate 41

[0042] First dielectric layer 411

[0043] First intermediate circuit layer 412

[0044] Transmission line 4121

[0045] First intermediate conductive structure 413

[0046] First outer side circuit layer 414

[0047] First outer side conductive structure 415

[0048] Second circuit substrate 42

[0049] Second dielectric layer 421

[0050] Second outer side circuit layer 422

[0051] Second outer side conductive structure 423

[0052] Antenna module 200

[0053] Chip 201

[0054] Antenna 202

[0055] Thickness direction H

[0056] The following detailed description will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application.

[0058] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or can exist simultaneously with a middle element. When an element is considered to be "provided on" another element, it can be directly provided on the other element or can exist simultaneously with a middle element.

[0059] Referring to Figures 1 to 6 The present application provides a manufacturing method of a high-frequency transmission circuit board 100, comprising the steps of:

[0060] S1: Referring to Figure 5 , a core board 10 is provided, the core board 10 comprising a substrate layer 11, a first inner side circuit layer 12, a second inner side circuit layer 13, and a plurality of inner side conductive structures 14. The first inner side circuit layer 12 and the second inner side circuit layer 13 are respectively arranged on opposite sides of the substrate layer 11, and the inner side conductive structures 14 are arranged inside the substrate layer 11. The inner side conductive structures 14 are electrically connected to the first inner side circuit layer 12 and the second inner side circuit layer 13. The inner side conductive structures 14 comprise conductive paste 30 and hollow conductive bodies 32, the conductive paste 30 is filled into the hollow conductive bodies 32, and the conductive paste 30 and the conductive bodies 32 are used for transmitting high-frequency electromagnetic signals.

[0061] Referring to Figures 1 to 4 In this embodiment, in step S1, the manufacturing method of the core board 10 comprises:

[0062] S10: Referring to Figure 1 , a double-sided copper-clad substrate 20 is provided, the double-sided copper-clad substrate 20 comprising the substrate layer 11, a first copper foil layer 21, and a second copper foil layer 22. The first copper foil layer 21 and the second copper foil layer 22 are respectively arranged on opposite sides of the substrate layer 11. The double-sided copper-clad substrate 20 has a thickness direction H, and the double-sided copper-clad substrate 20 is provided with a plurality of openings 23, the openings 23 penetrating through the first copper foil layer 21, the substrate layer 11, and the second copper foil layer 22 along the thickness direction H.

[0063] S11: Referring to Figure 2 , a first electroplated layer 24 is arranged on the first copper foil layer 21, and a second electroplated layer 25 is arranged on the second copper foil layer 22. Part of the first electroplated layer 24 and part of the second electroplated layer 25 are filled into the openings 23 to form the hollow conductive bodies 32.

[0064] S12: Please refer to Figure 3 , a conductive paste 30 is arranged in the hollow conductive body 32, wherein the material of the conductive paste 30 includes an adhesive and a conductive powder, the adhesive includes at least one of polyurethane resin, polyurethane rubber, acrylic resin, acrylic rubber, butyl rubber, chlorosulfonated rubber, fluororubber, and silicone, and the conductive powder includes at least one of copper powder, gold powder, zinc powder, and graphite powder.

[0065] S13: Please refer to Figure 4 , the first copper foil layer 21 and the first electroplated layer 24 are etched to form the first inner side circuit layer 12, and the second copper foil layer 22 and the second electroplated layer 25 are etched to form the second inner side circuit layer 13, thereby obtaining the core board 10.

[0066] Please refer to Figure 4 In the embodiment, the first inner side circuit layer 12 and the second inner side circuit layer 13 further include a plurality of positioning pads 31, the positioning pads 31 are arranged outside the conductive paste 30, and the end surface of the conductive paste 30 is flush with the side of the positioning pads 31 away from the substrate layer 11.

[0067] Please refer to Figure 7 In another embodiment of the present application, a core board 10a is provided, which is different in that the core board 10a does not include the hollow conductive body 32, and the opening 23 is filled with the conductive paste 30. The conductive paste 30 is used to transmit high-frequency signals.

[0068] S2: Please refer to Figure 5 , a first circuit substrate 41 is arranged on the first inner side circuit layer 12, and the first circuit substrate 41 is electrically connected to the first inner side circuit layer 12. Specifically, first, the positioning pads 31 on the core board 10 are identified by an image recognition device, then the core board 10 is accurately positioned by a mechanical arm or the like, and finally the first circuit substrate 41 is placed on the positioned core board 10 by the mechanical arm, and the first circuit substrate 41 and the core board 10 are pressed together.

[0069] Please refer to Figure 5In the embodiment, the first circuit substrate 41 comprises a first dielectric layer 411, a first intermediate circuit layer 412, and a plurality of first intermediate conductive structures 413. The first dielectric layer 411 is arranged on the first inner circuit layer 12, the first intermediate circuit layer 412 and the first intermediate conductive structures 413 are arranged in the first dielectric layer 411. The first intermediate conductive structures 413 are electrically connected between the first inner circuit layer 12 and the first intermediate circuit layer 412, and the first intermediate conductive structures 413 correspond to the first inner conductive structures 14. In the embodiment, the material of the first intermediate conductive structures 413 is adhesive and conductive powder, the adhesive comprises at least one of polyurethane resin, polyurethane rubber, acrylic resin, acrylic rubber, butyl rubber, chlorosulfonated rubber, fluororubber, and silicone, and the conductive powder comprises at least one of copper powder, gold powder, zinc powder, and graphite powder. In other embodiments of the present application, the material of the first intermediate conductive structures 413 can also be copper, aluminum, iron, or the like.

[0070] In the embodiment, the first circuit substrate 41 further comprises a first outer circuit layer 414 and a plurality of first outer conductive structures 415, the first outer circuit layer 414 is arranged on the side of the first dielectric layer 411 away from the first inner circuit layer 12, and the first outer conductive structures 415 are arranged between the first intermediate circuit layer 412 and the first outer circuit layer 414. The first outer circuit layer 414 is used to connect the chip 201 (see Figure 6 ) to process electromagnetic signals.

[0071] Please refer to Figure 5 In the embodiment, the first intermediate circuit layer 412 comprises a plurality of transmission lines 4121, the cross-sectional projection of the transmission lines 4121 along the thickness direction H is located in the end surface of the conductive paste 30, thereby facilitating the reduction of the capacitance between the transmission lines 4121 and the positioning pads 31, thereby reducing impedance discontinuity and improving the transmission quality of high-frequency signals through the conductive paste 30.

[0072] S3: Please refer to Figure 5 , a second circuit substrate 42 is arranged on the second inner circuit layer 13, the second circuit substrate 42 is electrically connected to the second inner circuit layer 13, and the high-frequency transmission circuit board 100 is obtained. Specifically, first, the positioning pads 31 on the core board 10 are identified by an image recognition device, then the core board 10 is accurately positioned by a mechanical arm or the like, and finally the second circuit substrate 42 is placed on the positioned core board 10 by a mechanical arm, and the first circuit substrate 41 and the core board 10 are pressed together.

[0073] Please refer to Figure 5In the embodiment, the second circuit substrate 42 comprises a second dielectric layer 421, a second outer circuit layer 422 and a second outer conductive structure 423. The second dielectric layer 421 is arranged on the second inner circuit layer 13, the second outer circuit layer 422 is arranged on the side of the second dielectric layer 421 away from the second inner circuit layer 13, and the second outer conductive structure 423 electrically connects the second outer circuit layer 422 and the second inner circuit layer 13. The second outer circuit layer 422 is used to arrange an antenna 202 (see Figure 6 In the embodiment, the material of the second outer conductive structure 423 is adhesive and conductive powder, the adhesive comprises at least one of polyurethane resin, polyurethane rubber, acrylic resin, acrylic rubber, butyl rubber, chlorosulfonated rubber, fluororubber and silicone, and the conductive powder comprises at least one of copper powder, gold powder, zinc powder and graphite powder. In other embodiments of the present application, the material of the second outer conductive structure 423 can also be metal such as copper, aluminum and iron.

[0074] Please refer to Figure 5 The present application also provides a high-frequency transmission circuit board 100, which comprises a core board 10, a first circuit substrate 41 and a second circuit substrate 42, and the first circuit substrate 41 and the second circuit substrate 42 are arranged on opposite sides of the core board 10, respectively.

[0075] The core board 10 comprises a substrate layer 11, a first inner circuit layer 12, a second inner circuit layer 13 and a plurality of inner conductive structures 14. The first inner circuit layer 12 and the second inner circuit layer 13 are arranged on opposite sides of the substrate layer 11, respectively, the inner conductive structures 14 are arranged in the substrate layer 11, the inner conductive structures 14 electrically connect the first inner circuit layer 12 and the second inner circuit layer 13, and the inner conductive structures 14 comprise conductive paste 30.

[0076] The first inner circuit layer 12 is electrically connected to the first circuit substrate 41, and the second inner circuit layer 13 is electrically connected to the second circuit substrate 42.

[0077] Compared with the prior art, the high-frequency transmission circuit board 100 provided by the present application has the following advantages:

[0078] (1) By arranging the conductive paste 30 in the core board 10, the conductive paste 30 is used to realize high-frequency signal transmission between layers, the method of filling the conductive paste 30 is not easy to have holes or recesses, and the operation is simple and easy to control, thereby reducing the problems of cavities or recesses that are easy to occur by forming solid conductive pillars through electroplating or chemical plating, and at the same time, the combination ability of the conductive paste 30 with the positioning pad 31 is good, and the heat dissipation performance is good.

[0079] (ii) by setting the cross-sectional projection of the conductive paste 30 along the thickness direction H to be located within the positioning pad 31, the cross-sectional projection of the transmission line 4121 along the thickness direction H is located within the end surface of the conductive paste 30, thereby facilitating reduction of the capacitance between the transmission line 4121 and the positioning pad 31, thereby reducing impedance discontinuity, and facilitating improvement of the transmission quality of high-frequency signals through the conductive paste 30.

[0080] Please refer to Figure 6 The embodiments of the present application also provide an antenna module 200, which comprises a chip 201, an antenna 202, and the high-frequency transmission circuit board 100. The chip 201 is arranged on the first outer side circuit layer 414, and the antenna 202 is arranged on the second outer side circuit layer 422.

[0081] In addition, those skilled in the art can make other changes within the spirit of the present application, of course, these changes according to the spirit of the present application, all should be included in the scope of the present application claimed.

Claims

1. A method of manufacturing a circuit board, characterized by, The method comprises the steps of: providing a core board, the core board comprising a substrate layer, a first inner side circuit layer, a second inner side circuit layer, and a plurality of inner side conductive structures, the first inner side circuit layer and the second inner side circuit layer being respectively arranged on opposite sides of the substrate layer, the inner side conductive structures being arranged in the substrate layer, the inner side conductive structures electrically connecting the first inner side circuit layer and the second inner side circuit layer, the inner side conductive structures comprising conductive paste; arranging a first circuit substrate on the first inner side circuit layer, the first circuit substrate electrically connecting the first inner side circuit layer; and arranging a second circuit substrate on the second inner side circuit layer, the second circuit substrate electrically connecting the second inner side circuit layer, to obtain the circuit board, wherein the first inner side circuit layer and the second inner side circuit layer further comprise a plurality of positioning pads, the positioning pads being arranged around the conductive structures, the first circuit substrate is internally provided with a transmission line and a first intermediate conductive structure connected to one end of the transmission line, the other end of the intermediate conductive structure away from the transmission line being connected to the positioning pad, in the thickness direction of the circuit board, the cross-sectional projection of the transmission line is located in the conductive paste, and the cross-sectional projection of the conductive paste is located in the positioning pad.

2. The production method according to claim 1, wherein The manufacturing method of the core board comprises: providing a double-sided copper-clad substrate, the double-sided copper-clad substrate comprising a substrate layer, a first copper foil layer, and a second copper foil layer, the first copper foil layer and the second copper foil layer being respectively arranged on opposite sides of the substrate layer, the double-sided copper-clad substrate being provided with an opening, the opening penetrating through the first copper foil layer, the substrate layer, and the second copper foil layer; arranging a first electroplated layer on the first copper foil layer, and a second electroplated layer on the second copper foil layer, part of the first electroplated layer and part of the second electroplated layer being filled into the opening to form a hollow conductive body; arranging the conductive paste in the conductive body; and etching the first copper foil layer and the second electroplated layer to form the first inner side circuit layer, and etching the second copper foil layer and the second electroplated layer to form the second inner side circuit layer, to obtain the core board.

3. The production method according to claim 1, wherein The material of the conductive paste comprises an adhesive and conductive powder, the adhesive comprising at least one of polyurethane resin, polyurethane rubber, acrylic resin, acrylic rubber, butyl rubber, chlorosulfonated rubber, fluororubber, and silicone, and the conductive powder comprising at least one of copper powder, gold powder, zinc powder, and graphite powder.

4. A circuit board, characterized by The core board, the first circuit substrate, and the second circuit substrate are respectively arranged on opposite sides of the core board, the core board comprising a substrate layer, a first inner side circuit layer, a second inner side circuit layer, and a plurality of inner side conductive structures, the first inner side circuit layer and the second inner side circuit layer being respectively arranged on opposite sides of the substrate layer, the inner side conductive structures being arranged in the substrate layer, the inner side conductive structures electrically connecting the first inner side circuit layer and the second inner side circuit layer, the inner side conductive structures comprising conductive paste, The first inner side circuit layer is electrically connected to the first circuit substrate, and the second inner side circuit layer is electrically connected to the second circuit substrate. The first inner side circuit layer and the second inner side circuit layer further comprise a plurality of positioning pads, which are arranged around the conductive structure. The first circuit substrate is provided with a first intermediate conductive structure and a transmission line connected to one end of the first intermediate conductive structure. In the thickness direction of the circuit board, the cross-sectional projection of the transmission line is located in the conductive paste, and the cross-sectional projection of the conductive paste is located in the positioning pad.

5. The circuit board of claim 4, wherein, The inner side conductive structure further comprises a hollow conductive body, the substrate layer is provided with an opening, the conductive body is arranged in the opening, the conductive paste is arranged in the conductive body, and the opposite ends of the conductive body are electrically connected to the first inner side circuit layer and the second inner side circuit layer.

6. The circuit board of claim 4, wherein, The first circuit substrate further comprises a first dielectric layer and a first intermediate circuit layer, the first dielectric layer is arranged on the first inner side circuit layer, the first intermediate circuit layer and the first intermediate conductive structure are arranged in the first dielectric layer, the first intermediate conductive structure is electrically connected between the first inner side circuit layer and the first intermediate circuit layer, and the first intermediate conductive structure corresponds to the inner side conductive structure.

7. The circuit board of claim 6, wherein, The first circuit substrate further comprises a first outer side circuit layer and a plurality of first outer side conductive structures, the first outer side circuit layer is arranged on the side of the first dielectric layer away from the first inner side circuit layer, and the first outer side conductive structures are arranged between the first intermediate circuit layer and the first outer side circuit layer.

8. The circuit board of claim 4, wherein, The second circuit substrate comprises a second dielectric layer, a second outer side circuit layer and a second outer side conductive structure, the second dielectric layer is arranged on the second inner side circuit layer, the second outer side circuit layer is arranged on the side of the second dielectric layer away from the second inner side circuit layer, and the second outer side conductive structure is electrically connected between the second outer side circuit layer and the second inner side circuit layer.

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