TWI823523B - Circuit board and method for manufacturing the same - Google Patents

Abstract

A circuit board includes a third circuit substrate, a second adhesive layer, a second circuit substrate, a first adhesive layer, a first circuit substrate, a third adhesive layer, and a fourth circuit substrate which are stacked in that order. The circuit board defines a first cavity and a second cavity. The first cavity penetrates the third adhesive layer, the first circuit substrate, and the second adhesive layer. The second cavity penetrates the third adhesive layer, the first circuit substrate, the first adhesive layer, the second circuit substrate, and the second adhesive layer. A side wall of the first cavity is covered with a first metal layer, a side wall of the second cavity is covered with a second metal layer. The second circuit substrate includes a first metal pad, the first metal pad is exposed in the first cavity and is spaced apart from the first metal layer by a predetermined distance. The third circuit substrate includes a second metal pad, the second metal pad is exposed in the second cavity and is spaced apart from the second metal layer by a predetermined.

Description

Circuit board and method of making the same

The present application relates to the technical field of circuit boards, and in particular, to a circuit board with an air waveguide and a manufacturing method thereof.

In the microwave and millimeter wave frequency bands, as the frequency band becomes crowded, the frequency required for signal transmission gradually increases. If traditional microstrip lines and strip lines are used, their losses cannot be ignored and seriously affect the signal transmission quality. One solution is to use a waveguide structure. Due to its good shielding characteristics, the waveguide structure can ensure the transmission of high-power bottom-dispersed microwave and millimeter-wave signals with very little loss. Existing circuit boards with waveguide structures are generally only used to transmit radio wave signals between outer layers, and their use is limited.

In view of this, it is necessary to provide a circuit board and a manufacturing method thereof that can solve the above technical problems.

A first aspect of the application provides a circuit board, including a third circuit substrate, a second adhesive layer, a second circuit substrate, a first adhesive layer, a first circuit substrate, a third adhesive layer and a fourth circuit substrate that are stacked in sequence. The circuit board is provided with a first cavity and a second cavity. The first cavity penetrates the third glue layer, the first circuit substrate and the second glue layer. The second cavity Penetrating the third glue layer, the first circuit substrate, the first glue layer, the second circuit substrate and the second glue layer, the side wall of the first cavity is covered with a first metal layer , the side walls of the second cavity are covered with a second metal layer, the second circuit substrate includes a first metal pad, the first metal pad is exposed in the first cavity and Separated from the first metal layer by a preset distance, the third circuit substrate includes a second metal pad, the second metal pad is exposed in the second cavity and is spaced from the second metal layer by a preset distance. distance.

In some embodiments, the circuit board further includes first conductive paste and second conductive paste sandwiched between the fourth circuit substrate and the first circuit substrate, the first conductive paste surrounding the The opening of the first cavity is disposed and connected to the first metal layer, and the second conductive paste is disposed around the opening of the second cavity and connected to the second metal layer.

In some embodiments, the circuit board further includes a third conductive paste sandwiched between the third circuit substrate and the second circuit substrate, the third conductive paste surrounding the second cavity The opening is provided and connected to the second metal layer.

In some embodiments, the circuit board further includes a first ventilation hole and a second ventilation hole. The first ventilation hole penetrates the fourth circuit substrate and communicates with the first cavity. The second ventilation hole The hole penetrates the fourth circuit substrate and communicates with the second cavity.

In some embodiments, the circuit board further includes two covering layers located on the outside, one covering layer covering the third circuit substrate, and the other covering layer covering the fourth circuit substrate.

A second aspect of the present application provides a method for manufacturing a circuit board, which includes the following steps: sequentially stacking and pressing a first substrate, a second adhesive layer, a second circuit substrate, a first adhesive layer and a first circuit substrate to form an intermediate body. The second circuit substrate includes a first metal pad that is bonded to the first adhesive layer, and the first substrate includes a second metal pad that is bonded to the second adhesive layer; forming a penetrating first circuit The substrate and the first glue layer expose the first cavity of the first metal pad, forming a structure that penetrates the first circuit substrate, the first glue layer, the second circuit substrate and the second glue. layer and expose the second cavity of the second metal pad; perform electroplating on the first cavity and the second cavity, and form a first metal layer on the side wall and bottom wall of the first cavity respectively. and a third metal layer. A second metal layer and a fourth metal layer are respectively formed on the side walls and bottom walls of the second cavity; the third metal layer is removed to expose the first metal pad, and the third metal layer is removed. Four metal layers are used to expose the second metal pad. There is a preset distance between the first metal pad and the first metal layer, and a preset distance between the second metal pad and the second metal layer. distance; Stack and press the intermediate body, the third glue layer and the second substrate in sequence, and the second substrate covers the openings of the first cavity and the second cavity; The second substrate is subjected to circuit fabrication to obtain a third circuit substrate and a fourth circuit substrate.

In some embodiments, before the step of "sequentially stacking and pressing the intermediate body, the third adhesive layer and the second substrate", the following steps are also included: forming a first conductive paste and a second conductive paste on the first circuit substrate. Conductive paste, the first conductive paste is placed around the opening of the first cavity, the second conductive paste is placed around the opening of the second cavity; the intermediate body, the third conductive paste are sequentially stacked and pressed After the glue layer and the second substrate, the first conductive paste is sandwiched between the first circuit substrate and the second substrate and connected to the first metal layer, and the second conductive paste is sandwiched between The first circuit substrate and the second substrate are connected to the second metal layer.

In some embodiments, the method further includes the following steps: forming a first ventilation hole and a second ventilation hole penetrating the fourth circuit substrate, the first ventilation hole being connected to the first cavity, and the second ventilation hole being connected to the first cavity. The hole communicates with the second cavity.

A third aspect of the present application provides a method for manufacturing a circuit board, including the following steps: sequentially stacking and laminating a second circuit substrate, a first adhesive layer and a first circuit substrate to form an intermediate body, the second circuit substrate including a first metal pad ; Form a first cavity that penetrates the first circuit substrate and the first glue layer and exposes the first metal pad, and form a second cavity that penetrates the intermediate body; to the first cavity Perform electroplating with the second cavity to form a first metal layer and a third metal layer on the side walls and bottom walls of the first cavity respectively, and form a second metal layer on the side walls of the second cavity; remove The third metal layer exposes the first metal pad, and the first metal pad is separated from the first metal layer by a preset distance; the first substrate, the second glue layer, and the middle layer are sequentially stacked and pressed together. body, a third glue layer and a second substrate, the first substrate includes a second metal pad, the second substrate covers the opening of the first cavity and the second cavity located on the same side, the The first substrate covers the opening on the other side of the second cavity and allows the The second metal pad is exposed in the second cavity, and the second metal pad is separated from the second metal layer by a preset distance; circuit fabrication is performed on the first substrate and the second substrate to obtain a third circuit substrate and a fourth circuit substrate.

In some embodiments, before the step of "sequentially stacking and pressing the first substrate, the second glue layer, the intermediate, the third glue layer and the second substrate", the following steps are also included: A first conductive paste and a second conductive paste are formed on the substrate, and the first conductive paste and the second conductive paste are respectively arranged around the opening on one side of the first cavity and the second cavity; A third conductive paste is formed on a substrate, and the third conductive paste is arranged around the second metal pad and spaced a preset distance from the second metal pad; the first substrate and the second adhesive layer are sequentially stacked and pressed , after the intermediate, the third glue layer and the second substrate, the first conductive paste is sandwiched between the first circuit substrate and the second substrate and connected to the first metal layer, so The second conductive paste is sandwiched between the first circuit substrate and the second substrate and connected to the second metal layer, and the third conductive paste is sandwiched between the second circuit substrate and the second metal layer. between the first substrate and the second metal layer.

In the circuit board and its manufacturing method provided by this application, first cavities and second cavities with different lengths are designed in the thickness direction of the circuit board, wherein the air waveguide formed by the first cavity is used for Transmitting radio wave signals between the inner circuit substrate and the outer circuit substrate can shorten the transmission path to reduce losses, provide better electrical characteristics, and can be transmitted with multi-layer antennas to have different antenna characteristics, and the second The air waveguide formed by the cavity can be used to transmit electric wave signals between the circuit substrates located on the outer layer, increasing the degree of design freedom.

100, 100’: circuit board

10: First circuit substrate

11: First base material layer

12: First conductive circuit layer

14: First conductive structure

15: First inner conductive circuit layer

20: Second circuit substrate

21: Second base material layer

22: Second conductive circuit layer

24: Second conductive structure

25: Second inner conductive circuit layer

26:Third conductive structure

401: First substrate

30: First glue layer

50: Second glue layer

60, 60’: intermediate

41: The third base material layer

42: The third conductive circuit layer

43: First conductor layer

61: First cavity

62, 62’: Second cavity

63, 63’: Tool hole

221:First metal pad

421: Second metal pad

611: First metal layer

612: The third metal layer

621, 621’: Second metal layer

622: The fourth metal layer

613:The first conductive paste

623: Second conductive paste

70:Third adhesive layer

801: Second substrate

81: The fourth base material layer

82: The fourth conductive circuit layer

83: Second conductor layer

110: The fourth conductive structure

40:Third circuit substrate

80: Fourth circuit substrate

90: Covering layer

624:Third conductive paste

91: First ventilation hole

92: Second ventilation hole

FIG. 1 is a schematic cross-sectional view of the first circuit substrate provided by the first embodiment of the present application.

FIG. 2 is a schematic cross-sectional view of the second circuit substrate provided by the first embodiment of the present application.

FIG. 3 is a schematic cross-sectional view of the first substrate, the second adhesive layer, the second circuit substrate, the first adhesive layer and the first circuit substrate provided in the first embodiment of the present application.

FIG. 4 is a schematic cross-sectional view of an intermediate body formed by laminating the first substrate, the second adhesive layer, the second circuit substrate, the first adhesive layer and the first circuit base shown in FIG. 3 together.

FIG. 5 is a schematic cross-sectional view after forming the first cavity and the second cavity on the intermediate body shown in FIG. 4 .

Figure 6 is a schematic cross-sectional view of the intermediate body, the third adhesive layer and the second substrate shown in Figure 5 being stacked in sequence.

Figure 7 is a schematic cross-sectional view of the intermediate body, the third adhesive layer and the second substrate shown in Figure 6 after they are pressed together.

Figure 8 is a schematic cross-sectional view of a circuit board provided by the first embodiment of the present application.

FIG. 9 is a schematic cross-sectional view of a second circuit substrate, a first adhesive layer and a first circuit substrate stacked in sequence according to the second embodiment of the present application.

FIG. 10 is a schematic cross-sectional view of an intermediate body formed by laminating the second circuit substrate, the first adhesive layer and the first circuit substrate shown in FIG. 9 together.

FIG. 11 is a schematic cross-sectional view after forming the first cavity and the second cavity on the intermediate body shown in FIG. 10 .

FIG. 12 is a schematic cross-sectional view after forming a first metal layer and a third metal layer on the side walls of the first cavity and the second cavity shown in FIG. 11 respectively.

FIG. 13 is a schematic cross-sectional view after forming the first metal pad in the first cavity shown in FIG. 12 .

Figure 14 is a schematic cross-sectional view of the first substrate, the second glue layer, the intermediate, the third glue layer and the second substrate provided in the second embodiment of the present application.

Figure 15 is a schematic cross-sectional view of a circuit board provided by the second embodiment of the present application.

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Mode. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the technical field belonging to the present invention. The terminology used in the embodiments of the present invention is for the purpose of describing particular embodiments only and is not intended to limit the present invention.

Referring to Figures 1 to 8, a first embodiment of the present application provides a method of manufacturing a circuit board 100, which includes the following steps:

Step S1, please refer to FIG. 1 to provide a first circuit substrate 10. The first circuit substrate 10 includes a first base material layer 11 and a first conductive circuit layer 12 disposed on the first base material layer 11. The first conductive circuit layer 12 is located outside the first circuit substrate 10 . The number of the first conductive circuit layers 12 may be one or two. In this embodiment, the number of the first conductive circuit layers 12 is two. The two first conductive circuit layers 12 are located outside the first circuit substrate 10 and arranged oppositely. The first base material layer 11 The two first conductive circuit layers 12 are electrically isolated, and the two first conductive circuit layers 12 are electrically connected through the first conductive structure 14 penetrating the first base material layer 11 .

The first circuit substrate 10 may be a single-layer substrate or a multi-layer substrate. For example, the first conductive circuit layer 12 is bonded to at least one surface of the first base material layer 11 to form a single-layer substrate. "Fit" in this application means contacting each other and fitting without clearance. In this embodiment, the first circuit substrate 10 is a multi-layer substrate. The first circuit substrate 10 includes a plurality of first base material layers 11 and a plurality of first inner conductive circuit layers 15. Each first inner conductive circuit layer 15 Adhering to the surface of the corresponding first base material layer 11, an adhesive layer 16 is provided between two adjacent first base material layers 11 to bond the two adjacent first base material layers 11 together. The two first conductive circuit layers 12 are attached to the two first base material layers 11 located on the outside, and the first conductive structure 14 penetrates the plurality of first base material layers 11 and the adhesive layer 16. The two first conductive circuit layers 12 and the plurality of first inner conductive circuit layers 15 are electrically connected.

The material of the first base material layer 11 can be, but is not limited to, fiberglass epoxy resin (FR-4), polyethylene naphthalate (PEN), polyimide (PI), polyethylene terephthalate. Ethylene glycol diformate (PET), One or more of polyethylene (PE) or polycarbonate (PC). In this embodiment, the material of the first base material layer 11 is FR-4.

The material of the adhesive layer 16 can be prepreg or resin. The resin includes phenolic resin, polyvinyl chloride resin, polyester resin, epoxy resin, polyurethane, polyvinyl ester, polyfluorocarbon resin, polyfluorocarbon resin, and polysulfide resin. Leimide resin, polymethyleneamine triazine resin, polyimide resin, polycyanate resin or epoxy polyphenylene ether. In this embodiment, the glue layer 16 is made of resin.

The first conductive structure 14 may be a conductive pillar or a conductive hole. In this embodiment, the first conductive structure 14 is a conductive hole formed by electroplating, and the conductive hole may be filled with resin.

In some embodiments, the first circuit substrate 10 is manufactured using a circuit board manufacturing method commonly used in the art. For example, lamination, exposure, development, and circuit etching are performed on one copper-clad laminate to form the first circuit substrate 10; or lamination, exposure, development, and circuit etching are performed on a plurality of copper-clad laminates, and then the plurality of copper-clad laminates that have undergone circuit etching are It is pressed with the adhesive layer 16 to form the first circuit substrate 10 . The lamination, exposure, development, circuit etching, lamination and other steps are commonly used technical means in this field and will not be described in detail here.

Step S2, please refer to FIG. 2 to provide a second circuit substrate 20. The second circuit substrate 20 includes a second base material layer 21 and a second conductive circuit layer 22 disposed on the second base material layer 21. The second conductive circuit layer 22 is located outside the second circuit substrate 20 and includes a first metal pad 221 . The first metal pad 221 is used to form resonance. The number of the second conductive circuit layers 22 may be one or two. In this embodiment, the number of the second conductive circuit layers 22 is two. The two second conductive circuit layers 22 are located outside the second circuit substrate 20 and arranged oppositely. The second base material layer 21 The two second conductive circuit layers 22 are electrically isolated, and the two second conductive circuit layers 22 are electrically connected through the second conductive structure 24 penetrating the second base material layer 21 .

The second circuit substrate 20 may be a single-layer substrate or a multi-layer substrate. For example, the second conductive circuit layer 22 is bonded to at least one surface of the second base material layer 21 to form a single-layer substrate. "Fit" in this application means contacting each other and fitting without clearance. In this embodiment, the second circuit substrate 20 is a multi-layer substrate. The second circuit substrate 20 includes a plurality of second base material layers 21 and a plurality of second inner conductive circuit layers 25. Each second inner conductive circuit layer 25 Adhering to the surface of the corresponding second base material layer 21, two adjacent second An adhesive layer 16 is provided between the base material layers 21 to bond the two adjacent second base material layers 21 together. The two second conductive circuit layers 22 are attached to the two second base material layers 22 located outside. On the material layer 21, the second conductive structure 24 penetrates the second base material layer 21 and the adhesive layer 16 and electrically connects the two second conductive circuit layers 22 and the plurality of second inner conductive layers. Line layer 25.

In some embodiments, the second circuit substrate 20 further includes a third conductive structure 26 that penetrates the second base material layer 21 and the adhesive layer 16 and is electrically connected to a second conductive structure 26 . Circuit layer 22 and a second inner conductive circuit layer 25.

The material of the second base material layer 21 is selected from materials with low dielectric constant and low dielectric loss, such as but not limited to liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE), polyetheretherketone ( One or more of PEEK) and polyphenylene ether (PPO).

The second conductive structure 24 may be a conductive pillar or a conductive hole. In this embodiment, the second conductive structure 24 is a conductive hole formed by electroplating, and the conductive hole may be filled with resin.

Step S3, please refer to Figures 3 and 4. A first substrate 401, a first glue layer 30 and a second glue layer 50 are provided, and the first substrate 401, the second glue layer 50, and the above are sequentially stacked and pressed. The second circuit substrate 20 , the first adhesive layer 30 and the first circuit substrate 10 are combined to obtain an intermediate 60 .

The first substrate 401 includes a third base material layer 41 and a third conductive circuit layer 42 and a first conductor layer 43 disposed on opposite surfaces of the third base material layer 41 . The third conductive circuit layer 42 is attached to the second adhesive layer 50 , and the first conductor layer 43 is located outside the intermediate body 60 . The third conductive circuit layer 42 includes a second metal pad 421 . The second metal pad 421 is used to form resonance.

The material of the first adhesive layer 30 can be prepreg or resin, and the resin includes phenolic resin, polyvinyl chloride resin, polyester resin, epoxy resin, polyurethane, polyvinyl ester, polyfluorocarbon resin, polyfluorocarbon resin, polyfluorocarbon resin, Bismaleimide resin, polymaleimide resin, polyimide resin, polycyanurate resin or epoxy polyphenylene ether. In this embodiment, the first glue layer 30 is made of resin.

The third base material layer 41 and the second adhesive layer 50 can be made of materials with low dielectric constant and low dielectric loss, such as but not limited to one of LCP, PTFE, PEEK, and PPO. or more.

After lamination, a first conductive circuit layer 12 and the first conductor layer 43 of the first circuit substrate 10 are located outside the intermediate body 60, and the third conductive circuit layer 42 and the second glue are The layers 50 are bonded together, and a second conductive circuit layer 22 of the second circuit substrate 20 is bonded with the first adhesive layer 30 .

Step S4, please refer to FIG. 4 and FIG. 5 to form a first cavity 61 penetrating the first circuit substrate 10 and the first adhesive layer 30 and exposing the first metal pad 221. A circuit substrate 10, the first adhesive layer 30, the second circuit substrate 20 and the second adhesive layer 50 expose the second cavity 62 of the second metal pad 421, forming a connection through the middle The tool hole 63 of the body 60.

The first cavity 61 , the second cavity 62 and the tool hole 63 can be formed by mechanical drilling or laser ablation. In this embodiment, the first cavity 61 and the second cavity 62 are drilled by a mechanical drilling machine with depth control.

Step S5, please refer to Figure 5. The first cavity 61 and the second cavity 62 are electroplated, and a first metal layer 611 and a third metal layer are formed on the side walls and bottom walls of the first cavity 61 respectively. Metal layer 612, a second metal layer 621 and a fourth metal layer 622 are respectively formed on the side walls and bottom walls of the second cavity 62.

The first metal layer 611 covers the entire side wall of the first cavity 61 and is connected to the first conductive circuit layer 12 and the second conductive circuit layer 22 . The third metal layer 612 covers the first metal pad 221 and is connected to the first metal layer 611 . The second metal layer 621 covers the entire side wall of the second cavity 62 and is connected to the first conductive circuit layer 12 and the third conductive circuit layer 42 . The fourth metal layer 622 covers the second metal pad 421 and is connected to the second metal layer 621 .

Step S6, please refer to Figures 5 and 6. The third metal layer 612 is removed to expose the first metal pad 221, and the fourth metal layer 622 is removed to expose the second metal pad 421. A metal pad 221 is spaced a preset distance from the first metal layer 611 , and a preset distance is spaced between the second metal pad 421 and the second metal layer 621 .

In some embodiments, the third metal layer 612 and the fourth metal layer 622 are removed using a mechanical drill with depth control. Through depth control, it can be ensured that the first metal layer 611 , the first metal pad 221 , and the second metal pad 421 will not be damaged during the formation of the first metal pad 221 and the second metal pad 421 . The metal layer 621 and the second metal pad 421 cause damage.

Step S7, please refer to FIGS. 6 and 7 , forming a first conductive paste 613 and a second conductive paste 623 on the first conductive circuit layer 12 , and the first conductive paste 613 surrounds the first cavity 61 The second conductive paste 623 is arranged around the opening of the second cavity 62; the intermediate body 60, the third glue layer 70 and the second substrate 801 are sequentially stacked and pressed. The second substrate 801 covers the third glue layer 70 , the first conductive paste 613 and the second conductive paste 623 , and seals the first cavity 61 and the second cavity 62 Open your mouth.

The first conductive paste 613 and the second conductive paste 623 may be made of metal paste, such as copper paste. The first conductive paste 613 and the second conductive paste 623 can be formed by printing. In other embodiments, the first conductive paste 613 may also be formed on the second substrate 801 .

The second substrate 801 includes a fourth base material layer 81 and a fourth conductive circuit layer 82 and a second conductor layer 83 disposed on two opposite surfaces of the fourth base material layer 81 . The fourth base material layer 81 can be made of a material with low dielectric constant and low dielectric loss, such as but not limited to one or more of LCP, PTFE, PEEK, and PPO.

The third adhesive layer 70 covers the first conductive circuit layer 12 and is attached to the fourth conductive circuit layer 82 for bonding the second substrate 801 and the intermediate body 60 . The material of the third adhesive layer 70 can be prepreg or resin. The resin includes phenolic resin, polyvinyl chloride resin, polyester resin, epoxy resin, polyurethane, polyvinyl ester, polyfluorocarbon resin, polyfluorocarbon resin, polyfluorocarbon resin, etc. Bismaleimide resin, polymaleimide resin, polyimide resin, polycyanurate resin or epoxy polyphenylene ether. In this embodiment, the third glue layer 70 is made of resin.

The first conductive paste 613 is bonded to the fourth conductive circuit layer 82 and the first conductive circuit layer 12 to prevent the third adhesive layer 70 from flowing into the first cavity 61 during lamination. middle. Place The second conductive paste 623 is attached to the fourth conductive circuit layer 82 and the first conductive circuit layer 12 to prevent the third adhesive layer 70 from flowing into the second cavity 62 during lamination. .

Step S8, please refer to FIG. 7 to form a plurality of fourth conductive structures 110 for electrically connecting the second substrate 801 and the first circuit substrate 10, and electrically connecting the second conductive layer 83 and the fourth conductive structure. The circuit layer 82 electrically connects the first conductor layer 43 and the third conductive circuit layer 42 . The fourth conductive structure 110 may be a conductive hole or a conductive pillar. In this embodiment, the fourth conductive structure 110 is a conductive hole, which is formed by drilling and electroplating.

In step S9, please refer to FIG. 8. Circuit fabrication is performed on the first conductor layer 43 and the second conductor layer 83 to form a third conductive circuit layer 42 and a fourth conductive circuit layer 82, respectively, to obtain the circuit board 100.

The third base material layer 41 and the two third conductive circuit layers 42 disposed on opposite sides of the third base material layer 41 constitute a third circuit substrate 40 . The fourth base material layer 81 and the two fourth conductive circuit layers 82 disposed on opposite sides of the fourth base material layer 81 constitute a fourth circuit substrate 80 .

In some embodiments, the manufacturing method of the circuit board 100 further includes the following steps:

In step S10 , please refer to FIG. 8 , two covering layers (CVL) 90 are formed on the outside of the circuit board 100 . The two covering layers 90 respectively cover the third conductive circuit layer 42 and the fourth conductive circuit layer 82 to protect the conductive circuits.

Step S11 , please refer to FIG. 8 , forming first ventilation holes 91 and second ventilation holes 92 penetrating the fourth circuit substrate 80 and the covering layer 90 thereon. The first ventilation hole 91 communicates with the external environment and the first cavity 61 , and the second ventilation hole 92 communicates with the external environment and the second cavity 62 , and is used to avoid the occurrence of noise when assembling the circuit board 100 at the rear end. Exploding board.

The first cavity 61 and the second cavity 62 contain air medium to form an air waveguide, and the circuit board 100 can use the air in the first cavity 61 and the second cavity 62 as conduction. medium to transmit radio signals. In this application, the first cavity 61 and the second cavity 62 with different lengths are designed in the thickness direction of the circuit board 100, wherein the air waveguide formed by the first cavity 61 is used in the inner layer. The electric wave signal is transmitted between the circuit substrate and the outer circuit substrate, which can shorten the transmission path. path to reduce loss, provide better electrical characteristics, and can be used with multi-layer antenna transmission to have different antenna characteristics, and the air waveguide formed by the second cavity 62 can be used to transmit radio wave signals between circuit substrates located on the outer layer. , improving the design freedom.

The second conductive circuit layer 22, the first metal layer 611, the first conductive circuit layer 12, the first conductive paste 613 and the fourth conductive circuit layer 82 are electrically connected to the third conductive circuit layer 82. The radio wave signal in a cavity 61 is blocked to provide an electromagnetic shielding effect. The third conductive circuit layer 42 , the second metal layer 621 , the second conductive paste 623 and the fourth conductive circuit layer 82 are electrically connected to enable the radio wave signal in the second cavity 62 to be processed. Block, providing electromagnetic masking effect.

Referring to Figures 9 to 15, a second embodiment of the present application provides a method of manufacturing a circuit board 100', which includes the following steps:

Step S1, please refer to Figures 9 and 10. The second circuit substrate 20, the first adhesive layer 30 and the first circuit substrate 10 are sequentially stacked and pressed to form an intermediate body 60'.

Step S2, please refer to Figures 10 and 11 to form a first cavity 61 penetrating the first circuit substrate 10 and the first adhesive layer 30 and exposing part of the first metal pad 221, forming a Second cavity 62' and tool hole 63' of intermediate body 60'. The second cavity 62' and the tool hole 63' both penetrate the first circuit substrate 10, the first adhesive layer 30 and the second circuit substrate 20.

Step S3, please refer to Figure 12, perform electroplating on the first cavity 61 and the second cavity 62', and form the first metal layer 611 on the side walls and bottom walls of the first cavity 61 respectively. and the third metal layer 612, and the second metal layer 621' is formed on the side wall of the second cavity 62'. The second metal layer 621′ covers the entire sidewall of the second cavity 62′ and is connected to the first conductive circuit layer 12 and the third conductive circuit layer 42.

Step S4, please refer to FIG. 12 and FIG. 13 , the third metal layer 612 is removed to expose the first metal pad 221 .

Step S5, please refer to Figures 14 and 15. A third conductive paste 624 is formed on the first substrate 401, and the first conductive paste 613 and the second conductive paste are formed on the first conductive circuit layer 12. Paste 623; stack and press the first substrate 401, the second glue layer 50, and the intermediate in sequence 60’, the third glue layer 70 and the second substrate 801. The third conductive paste 624 is formed on the third conductive circuit layer 42 and is disposed around the second metal pad 421 and spaced apart from the second metal pad 421 by a predetermined distance.

After pressing, the second substrate 801 covers the openings of the first cavity 61 and the second cavity 62' located on the same side, and the first substrate 401 covers the second cavity 62'. The opening on the other side exposes the second metal pad 421 to the second cavity 62 ′, and the second adhesive layer 50 is sandwiched between the second circuit substrate 20 and the first substrate 401 During this time, the third conductive paste 624 is attached to the second circuit substrate 20 to prevent the second adhesive layer 50 from flowing into the second cavity 62 ′, and the third conductive paste 624 surrounds the second cavity 62 ′. The opening of the second cavity 62' is disposed and connected to the second metal layer 621.

Step S5, please refer to FIG. 15 to form the plurality of fourth conductive structures 110, and perform circuit fabrication on the first conductor layer 43 and the second conductor layer 83 to form the third conductive circuit layer 42 and the second conductor layer 83. The fourth conductive circuit layer 82 forms the two outer covering layers 90 and forms the first ventilation holes 91 and the second ventilation holes penetrating the fourth circuit substrate 80 and the covering layer 90 thereon. 92. Obtain the circuit board 100'.

In addition, those skilled in the art can also make other changes within the spirit of the present invention. Of course, these changes made based on the spirit of the present invention should be included in the scope of protection claimed by the present invention.

100:Circuit board

10: First circuit substrate

11: First base material layer

12: First conductive circuit layer

20: Second circuit substrate

21: Second base material layer

22: Second conductive circuit layer

30: First glue layer

50: Second glue layer

41: The third base material layer

42: The third conductive circuit layer

61: First cavity

62:Second cavity

221:First metal pad

421: Second metal pad

611: First metal layer

621: Second metal layer

613:The first conductive paste

623: Second conductive paste

70:Third adhesive layer

81: The fourth base material layer

82: The fourth conductive circuit layer

110: The fourth conductive structure

40:Third circuit substrate

80: Fourth circuit substrate

90: Covering layer

91: First ventilation hole

92: Second ventilation hole

Claims (9)

A circuit board, which includes a third circuit substrate, a second glue layer, a second circuit substrate, a first glue layer, a first circuit substrate, a third glue layer and a fourth circuit substrate that are stacked in sequence, the circuit board A first cavity and a second cavity are provided. The first cavity penetrates the third glue layer, the first circuit substrate and the second glue layer. The second cavity penetrates the third glue layer. Three adhesive layers, the first circuit substrate, the first adhesive layer, the second circuit substrate and the second adhesive layer, the side wall of the first cavity is covered with a first metal layer, the third The side walls of the two cavities are covered with a second metal layer, the second circuit substrate includes a first metal pad, the first metal pad is exposed in the first cavity and is spaced a predetermined distance from the first metal layer. distance, the third circuit substrate includes a second metal pad, the second metal pad is exposed in the second cavity and is separated from the second metal layer by a preset distance; the circuit board also includes an intervening first conductive paste and second conductive paste between the fourth circuit substrate and the first circuit substrate, the first conductive paste is disposed around the opening of the first cavity and in contact with the first metal The second conductive paste is arranged around the opening of the second cavity and connected to the second metal layer. The circuit board of claim 1, wherein the circuit board further includes a third conductive paste sandwiched between the third circuit substrate and the second circuit substrate, the third conductive paste surrounding The opening of the second cavity is disposed and connected to the second metal layer. The circuit board according to claim 1, wherein the circuit board further includes a first ventilation hole and a second ventilation hole, the first ventilation hole penetrating the fourth circuit substrate and communicating with the first cavity , the second ventilation hole penetrates the fourth circuit substrate and communicates with the second cavity. The circuit board according to claim 1, wherein the circuit board further includes two covering layers located on the outside, one covering layer covers the third circuit substrate, and the other covering layer covers the fourth circuit substrate. A method for manufacturing a circuit board, which includes the following steps: sequentially stacking and pressing a first substrate, a second adhesive layer, a second circuit substrate, a first adhesive layer and a first circuit substrate to form an intermediate body, the second circuit The substrate includes a first metal pad that is bonded to the first glue layer, and the first substrate includes a second metal pad that is bonded to the second glue layer; Form a first cavity that penetrates the first circuit substrate and the first glue layer and exposes the first metal pad, and forms a first cavity that penetrates the first circuit substrate, the first glue layer, and the second circuit The substrate and the second glue layer are exposed to the second cavity of the second metal pad; the first cavity and the second cavity are electroplated, and the side walls and bottom of the first cavity are The walls respectively form a first metal layer and a third metal layer, and the side walls and bottom walls of the second cavity form a second metal layer and a fourth metal layer respectively; the third metal layer is removed to expose the first Metal pad, the fourth metal layer is removed to expose the second metal pad, the first metal pad is separated from the first metal layer by a preset distance, and the second metal pad is separated from the second metal pad. The metal layers are separated by a preset distance; the intermediate body, the third glue layer and the second substrate are sequentially stacked and pressed, and the second substrate covers the openings of the first cavity and the second cavity. ; Perform circuit fabrication on the first substrate and the second substrate to obtain a third circuit substrate and a fourth circuit substrate. The manufacturing method of a circuit board as described in claim 5, wherein before the step of "sequentially stacking and pressing the intermediate, the third adhesive layer and the second substrate", the following steps are also included: A first conductive paste and a second conductive paste are formed on the top, the first conductive paste is arranged around the opening of the first cavity, and the second conductive paste is arranged around the opening of the second cavity; after being stacked in sequence and After pressing the intermediate body, the third adhesive layer and the second substrate, the first conductive paste is sandwiched between the first circuit substrate and the second substrate and connected to the first metal layer, The second conductive paste is sandwiched between the first circuit substrate and the second substrate and connected to the second metal layer. The manufacturing method of a circuit board according to claim 5, further comprising the following steps: forming a first ventilation hole and a second ventilation hole penetrating the fourth circuit substrate, the first ventilation hole being in contact with the first ventilation hole. The cavities are connected, and the second ventilation hole is connected with the second cavity. A method of manufacturing a circuit board, which includes the following steps: A second circuit substrate, a first adhesive layer and a first circuit substrate are sequentially stacked and pressed to form an intermediate body. The second circuit substrate includes a first metal pad; The first cavity of the first metal pad is exposed to form a second cavity penetrating the intermediate body; the first cavity and the second cavity are electroplated, and the first cavity is A first metal layer and a third metal layer are formed on the side walls and bottom walls of the second cavity respectively, and a second metal layer is formed on the side wall of the second cavity; the third metal layer is removed to expose the first metal pad, and the The first metal pad is separated from the first metal layer by a preset distance; the first substrate, the second glue layer, the intermediate body, the third glue layer and the second substrate are sequentially stacked and pressed, and the first substrate includes The second metal pad, the second substrate covers the opening on the same side of the first cavity and the second cavity, the first substrate covers the opening on the other side of the second cavity and The second metal pad is exposed to the second cavity, and the second metal pad is separated from the second metal layer by a preset distance; performing circuit production on the first substrate and the second substrate A third circuit board and a fourth circuit board were obtained. The manufacturing method of a circuit board as described in claim 8, wherein before the step of "sequentially stacking and pressing the first substrate, the second adhesive layer, the intermediate, the third adhesive layer and the second substrate", it also includes The following steps: forming a first conductive paste and a second conductive paste on the first circuit substrate, the first conductive paste and the second conductive paste surrounding the first cavity and the second cavity respectively. An opening is located on one side; a third conductive paste is formed on the first substrate, and the third conductive paste is arranged around the second metal pad and spaced a preset distance from the second metal pad; and is stacked and pressed in sequence. After the first substrate, the second adhesive layer, the intermediate, the third adhesive layer and the second substrate are combined, the first conductive paste is sandwiched between the first circuit substrate and the second substrate and connected with The first metal layer is connected, the second conductive paste is sandwiched between the first circuit substrate and the second substrate and connected to the second metal layer, and the third conductive paste is sandwiched between The second circuit substrate is connected to the first substrate and to the second metal layer.

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