Circuit board hole plugging method and circuit board

Abstract

The invention discloses a hole plugging method of a circuit board and the circuit board. The hole plugging method comprises the steps of obtaining a to-be-processed board; wherein the plate to be treated comprises at least one through hole; using a first hole plugging material to plug the through hole for the first time, and enabling the first hole plugging material to fully plug the through hole; and performing secondary hole plugging on the through hole filled with the first hole plugging material by using a second hole plugging material, so as to eject the first hole plugging material through the second hole plugging material, and fully plugging the through hole with the second hole plugging material. According to the application, double-sided pressurization can be performed on the second hole plugging material through the hole plugging pressure and the extrusion force of the first hole plugging material reversely acting on the second hole plugging material, so that residual gas in the through hole and gas in the second hole plugging material are further discharged, and the probability of forming a cavity in the through hole is effectively reduced; and thus, the hole plugging yield and the product yield are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board processing, in particular to a hole plugging method of a circuit board and the circuit board. BACKGROUND

[0002] With the development of miniaturization of components, PCBs gradually develop towards miniaturization and high density, and the wiring density is continuously improved. With the increase of board thickness and hole density and the decrease of hole diameter, higher requirements are put forward for the hole plugging capability of through holes, blind holes and buried holes.

[0003] At present, in order to increase the three-dimensional density of PCBs, holes are usually arranged in the connecting pads, i.e. in-hole holes. In the related art, in order to improve the sealing performance and heat dissipation performance of the holes, a silk screen printing method is usually used to plug the holes with a hole plugging material, and after the hole plugging material is solidified, the hole mouth is ground to remove the excess hole plugging material, and then a circuit pattern is made.

[0004] However, when the hole diameter is small or the thickness-diameter ratio (i.e. the ratio of the thickness of the PCB to the hole diameter) is large, the yield of the hole plugging in the related art is low, which causes the holes to be prone to form cavities, thereby affecting the electrical performance of the PCB, and further affecting the long-term reliability and stability of the PCB. SUMMARY

[0005] The technical problem solved by the present application is to provide a hole plugging method of a circuit board and the circuit board, which can solve the problem of poor hole plugging in the related art.

[0006] To solve the above technical problem, the first technical solution adopted by the present application is to provide a hole plugging method of a circuit board, comprising: obtaining a to-be-processed board material; wherein the to-be-processed board material comprises at least one through hole; using a first hole plugging material to plug the through hole for the first time, and making the first hole plugging material fill the through hole; using a second hole plugging material to plug the through hole filled with the first hole plugging material for the second time, so as to eject the first hole plugging material through the second hole plugging material, and make the second hole plugging material fill the through hole.

[0007] The step of using the first hole plugging material to plug the through hole for the first time and making the first hole plugging material fill the through hole comprises: heating the first hole plugging material to melting, and plugging the melted first hole plugging material into the through hole until the first hole plugging material fills the through hole; and solidifying the first hole plugging material in the through hole.

[0008] The step of heating the first plugging material to a molten state and plugging the first plugging material into the through hole until the first plugging material fills the through hole includes: heating the first plugging material to a first critical temperature value to make the first plugging material in a viscous flow state; plugging the first plugging material in the viscous flow state into the through hole until the first plugging material in the viscous flow state fills the through hole; and the step of solidifying the first plugging material in the through hole includes: controlling the ambient temperature to be between the first critical temperature value and a second critical temperature value to make the first plugging material in the through hole solidify and be in an elastomeric state; and the second critical temperature value is lower than the first critical temperature value.

[0009] The step of plugging the first plugging material in the viscous flow state into the through hole until the first plugging material in the viscous flow state fills the through hole includes: plugging the first plugging material in the viscous flow state into the through hole by screen printing.

[0010] The step of solidifying the first plugging material in the through hole is followed by a step of removing the first plugging material protruding outside the through hole.

[0011] The step of plugging the through hole filled with the first plugging material with the second plugging material to push out the first plugging material and fill the through hole with the second plugging material includes: plugging the second plugging material into the through hole filled with the first plugging material to gradually push out the first plugging material in the elastomeric state; and solidifying the second plugging material after the second plugging material fills the through hole.

[0012] The step of plugging the second plugging material into the through hole filled with the first plugging material to gradually push out the first plugging material in the elastomeric state includes: plugging the second plugging material into the through hole filled with the first plugging material to gradually push out the first plugging material in the elastomeric state by screen printing at the same ambient temperature; and the step of solidifying the second plugging material after the second plugging material fills the through hole is followed by a step of removing the second plugging material protruding outside the through hole.

[0013] The thickness-diameter ratio of the through hole is greater than or equal to 6:1.

[0014] The first plugging material includes a thermoplastic resin, and the second plugging material includes a thermosetting resin.

[0015] To solve the above technical problems, the second technical solution adopted by the present application is to provide a circuit board made by the plugging method of the circuit board described above; and the circuit board includes at least one through hole, and the through hole is filled with the second plugging material.

[0016] The beneficial effects of the present application are: different from the prior art, the present application provides a circuit board plugging method and a circuit board, by using a first plugging material to perform first plugging on the through hole and filling the through hole with the first plugging material, the gas in the hole can be preliminarily discharged through the first plugging material. Further, the second plugging material is used to perform second plugging on the through hole filled with the first plugging material, so as to push out the first plugging material through the second plugging material and fill the through hole with the second plugging material, the second plugging material can be double-sidedly pressed by the plugging pressure and the extrusion pressure of the first plugging material acting on the second plugging material in the opposite direction, so that the residual gas in the through hole and the gas inside the second plugging material are further discharged, thereby effectively reducing the probability of forming a cavity in the through hole, and then improving the plugging yield and product yield. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 is a flowchart of a first embodiment of the circuit board plugging method of the present application;

[0019] Figure 2 is a flowchart of a second embodiment of the circuit board plugging method of the present application;

[0020] Figure 3 is a process diagram of performing first plugging on the to-be-processed board material;

[0021] Figure 4 is a structure diagram of an embodiment of the to-be-processed board material obtained in S23;

[0022] Figure 5 is a structure diagram of an embodiment of the to-be-processed board material obtained in S24;

[0023] Figure 6 is a process diagram of performing second plugging on the to-be-processed board material;

[0024] Figure 7 is a structure diagram of an embodiment of the to-be-processed board material obtained in S26;

[0025] Figure 8 is a structure diagram of an embodiment of the circuit board of the present application. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] The terms used in the examples of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a," "the," and "the" used in the examples of this application and the appended claims are also intended to include plural forms. Unless otherwise clearly indicated above, "a plurality" generally includes at least two, but does not exclude the inclusion of at least one.

[0028] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0029] It should be understood that the terms "comprises," "comprising," or any other variations used herein are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0030] In related technologies, in order to improve the airtightness and heat dissipation performance of the holes, screen printing is generally used to plug the holes in the circuit board with plugging materials. After the plugging materials are cured, the hole openings are ground to remove excess plugging materials, and then the circuit pattern is produced.

[0031] However, when the aperture is small or the thickness-to-diameter ratio is large, filling the hole using screen printing can face some challenges. When the aperture is very small, the flowability of the hole-filling material (e.g., resin, copper paste, etc.) is limited, and it is difficult to penetrate to the bottom and corners of the hole, resulting in incomplete filling of the hole. When the thickness-to-diameter ratio is large, the hole is relatively deep, and the hole-filling material needs more time and greater pressure to fill the entire hole, increasing the risk of air bubbles and incomplete filling. During the hole-filling process, the hole can be occupied by air or other gases. If these gases cannot be effectively removed before or during the filling of the hole-filling material, air bubbles will form, resulting in the formation of voids in the hole. Voids can cause the hole-filling material to be discontinuous, affecting the electrical conductivity of the circuit, increasing the resistance, and reducing the heat conduction efficiency of the PCB. Voids can also become a channel for moisture and chemical corrosion during the long-term use of the PCB, affecting the long-term reliability and stability of the PCB.

[0032] Based on the above, the present application provides a hole-filling method for a circuit board and a circuit board, which can solve the problem of poor hole-filling in the related art.

[0033] The present application will be described in detail below in conjunction with the drawings and embodiments.

[0034] Please refer to Figure 1 , Figure 1 is a flowchart of a first embodiment of a hole-filling method for a circuit board according to the present application. In this embodiment, the hole-filling method includes:

[0035] S11: Obtain a to-be-processed board; wherein the to-be-processed board includes at least one through hole.

[0036] In this embodiment, the to-be-processed board includes a multi-layer core board obtained by lamination.

[0037] Wherein, lamination refers to a method of combining two or more layers of the same or different materials into a whole with or without adhesive by heating and pressing. The core board is a copper-clad board, which includes a dielectric layer and a copper layer. The dielectric layer can cover the copper layer on one side or on both sides.

[0038] In this embodiment, the number of through holes is set according to actual needs. In some embodiments, the number of through holes is one. In other embodiments, the number of through holes is at least two. In yet other embodiments, the number of through holes can be three, five or more, which is not limited by the present application.

[0039] In some embodiments, the preselected region of the board to be processed is drilled by mechanical drilling, and the preselected region is drilled through to form at least one through hole. In other embodiments, the preselected region of the board to be processed is drilled by laser drilling, and the preselected region is drilled through to form at least one through hole. The present application does not limit the drilling method.

[0040] In some embodiments, the through hole is a metalized through hole to achieve interlayer interconnection.

[0041] S12: The first hole filling material is used to fill the through hole for the first time, and the first hole filling material is filled into the through hole.

[0042] In the present embodiment, the first hole filling material is filled into the through hole from the first end of the through hole, and the first hole filling material gradually fills the through hole until the first hole filling material extends from the second end of the through hole, and the first hole filling is completed.

[0043] It can be understood that by using the first hole filling material to fill the through hole for the first time, the gas in the through hole can be preliminarily discharged by the first hole filling material.

[0044] S13: The second hole filling material is used to fill the through hole filled with the first hole filling material for the second time, so that the first hole filling material is pushed out by the second hole filling material, and the through hole is filled with the second hole filling material.

[0045] In the present embodiment, the second hole filling material is filled into the through hole from the first end of the through hole, and the second hole filling material pushes the first hole filling material filled in the through hole in the direction from the first end to the second end under the hole filling pressure provided by the external device, so as to gradually push out the first hole filling material.

[0046] It can be understood that since the force is mutual, the first hole filling material will reversely extrude the second hole filling material in the direction from the second end to the first end.

[0047] It can be understood that by using the hole filling pressure and the extrusion force of the first hole filling material acting on the second hole filling material in the opposite direction to pressurize the second hole filling material from both sides, the remaining gas in the through hole and the gas inside the second hole filling material can be further discharged, so that the filling of the second hole filling material becomes continuous, thereby improving the performance of the circuit board.

[0048] Compared with the related art, the first plug material is used to plug the through hole for the first time, and the first plug material is filled in the through hole, so that the gas in the through hole can be preliminarily discharged by the first plug material. Furthermore, the second plug material is used to plug the through hole filled with the first plug material for the second time, so that the first plug material is pushed out by the second plug material, and the second plug material is filled in the through hole. The second plug material can be double-sidedly pressed by the plug pressure and the extrusion pressure of the first plug material acting on the second plug material in the opposite direction, so that the residual gas in the through hole and the gas in the second plug material are further discharged, thereby effectively reducing the probability of forming a cavity in the through hole, and then improving the plug yield and the product yield.

[0049] Please refer to Figure 2 , Figure 2 is a flowchart of a second embodiment of a plug method of a circuit board. In the embodiment, the plug method comprises the following steps.

[0050] S21: Obtain a to-be-processed board material; wherein the to-be-processed board material comprises at least one through hole.

[0051] For details, please refer to the description in S11, which will not be repeated here.

[0052] In some embodiments, the thickness-diameter ratio of the through hole is greater than or equal to 6:1.

[0053] S22: Heat the first plug material to be molten, and plug the molten first plug material into the through hole until the first plug material fills the through hole.

[0054] In the embodiment, the first plug material is heated to a first critical temperature value or higher, so that the first plug material is in a viscous flow state, and the first plug material in the viscous flow state is plugged into the through hole.

[0055] The first plug material comprises a thermoplastic resin. The thermoplastic resin used for plugging has good fluidity, adhesion, mechanical strength after solidification, and environmental resistance.

[0056] The thermoplastic resin exhibits different mechanical states at different temperatures, and the viscous flow state and the high-elasticity state are important physical states of the thermoplastic resin. When the temperature of the thermoplastic resin rises to a glass transition temperature (T g ) or higher but lower than a viscous flow temperature (T f) the molecular chain segment movement ability is enhanced, the thermoplastic resin is in the high-elastic state, but the whole molecular chain cannot freely slide. When the thermoplastic resin is in the high-elastic state, the elasticity is significant, and large reversible deformation can occur under external force, the modulus is low, it is softer than the glass state, but more tough than the viscous flow state, and is in a fixed state, and can be filled in the through hole. When the temperature is further increased to above the viscous flow temperature, the whole molecular chain of the thermoplastic resin can relatively slide, and the thermoplastic resin is transformed from the solid state to the flowable state, which can be called the melting state.

[0057] In the embodiment, the first critical temperature value is the viscous flow temperature corresponding to the first plug hole material.

[0058] In some embodiments, the thermoplastic resin can be any one or more of polyolefins, polyamides, polyesters, polyphenylene sulfide, thermoplastic polyurethane, polycarbonate, and the like, which are not limited in the application.

[0059] In some embodiments, the first critical temperature value is adjusted based on the type of the thermoplastic resin used.

[0060] In some embodiments, the first plug hole material in the viscous flow state is inserted into the through hole by means of screen printing.

[0061] In some embodiments, the obtained thermoplastic resin is heated to above the corresponding viscous flow temperature of the thermoplastic resin, so that the first plug hole material is in the viscous flow state. Then, the first plug hole material in the viscous flow state is placed on the screen plate corresponding to the screen printing device, and the first plug hole material is inserted into the through hole from the first end of the through hole using a printing doctor blade, so that the first plug hole material gradually fills the through hole until the first plug hole material extends from the second end of the through hole, and the first plug hole is completed.

[0062] Specifically, please refer to Figure 3 , Figure 3 is a process schematic diagram of the first plug hole of the plate to be processed.

[0063] In the embodiment, the board to be processed 100 includes a plurality of core boards 11, and prepreg 12 is arranged between adjacent core boards 11. The core board 11 includes a dielectric layer 13 and a copper layer 14 arranged on both sides of the dielectric layer. The board to be processed 100 includes at least one through hole 101. The first plug material 20 in a viscous flow state is placed on the screen plate 41, and the screen plate hole (not shown in the figure) is arranged on the screen plate 41, which is located above the through hole 101 of the board to be processed 100, and a through hole is formed between the screen plate hole and the through hole 101. The diameter of the screen plate hole is slightly larger, slightly smaller or the same as that of the through hole 101. The first plug material 20 is pressed into the screen plate hole by the printing doctor blade 42, so that the first plug material 20 is plugged into the through hole 101 through the screen plate hole. The printing doctor blade 42 is in contact with the screen plate 41 at a preset angle (for example, 60°-75°), and a preset pressure is applied, so that the first plug material 20 fills the screen plate hole and is transferred to the through hole 101 through the screen plate hole under the pushing of the printing doctor blade 42.

[0064] S23: The first plug material in the through hole is subjected to a curing treatment.

[0065] In the embodiment, the environmental temperature is controlled to be between the first critical temperature value and the second critical temperature value, so that the first plug material plugged into the through hole is cured and in a high-elastic state. The second critical temperature value is lower than the first critical temperature value.

[0066] The second critical temperature value is the glass transition temperature corresponding to the first plug material.

[0067] It can be understood that when the environmental temperature is between the first critical temperature value and the second critical temperature value, the first plug material entering the through hole will initially condense to form an elastic material in a high-elastic state due to the decrease in temperature. At this time, the first plug material will not be excessively solidified and still has relatively low fluidity and adhesion, so it can be filled in the through hole.

[0068] Specifically, refer to Figure 4 , Figure 4 is a structural schematic diagram of an embodiment of the board to be processed obtained in S23.

[0069] In the embodiment, the board to be processed 100 includes a plurality of core boards 11, and prepreg 12 is arranged between adjacent core boards 11. The core board 11 includes a dielectric layer 13 and a copper layer 14 arranged on both sides of the dielectric layer. The board to be processed 100 includes at least one through hole 101, and the through hole 101 is filled with the first plug material 20. The first plug material 20 forms a pore cavity 21 therein. The outside of the first end of the through hole 101 is formed with protruding first plug material 20.

[0070] S24: The first plug material protruding outside the through hole is removed.

[0071] In this embodiment, the first plug material protruding outside the via hole is removed by the brush plate at the same ambient temperature.

[0072] It can be understood that the first plug material may overflow outside the via hole and form protrusions or residues on the surface outside the via hole during the plugging process. Removing these protrusions can make the substrate surface flat, avoid affecting the subsequent process, and thus improve the functionality, reliability and process compatibility of the product.

[0073] Specifically, please refer to Figure 5 , Figure 5 is a structural schematic diagram of an embodiment of the to-be-processed board obtained in S24.

[0074] In this embodiment, the to-be-processed board 100 includes a plurality of core boards 11, and prepregs 12 are arranged between adjacent core boards 11. The core board 11 includes a dielectric layer 13 and a copper layer 14 arranged on both sides of the dielectric layer. The to-be-processed board 100 includes at least one via hole 101, and the via hole 101 is filled with a first plug material 20. The first plug material 20 has a pore cavity 21 formed therein.

[0075] S25: Plugging a second plug material into the via hole filled with the first plug material, so that the second plug material gradually pushes out the first plug material in a high-elastic state.

[0076] In this embodiment, the second plug material is plugged into the via hole filled with the first plug material by screen printing at the same ambient temperature, so that the second plug material gradually pushes out the first plug material in a high-elastic state.

[0077] The second plug material includes a thermosetting resin.

[0078] The thermosetting resin is a high-molecular material that undergoes irreversible cross-linking reaction (curing) after being heated, irradiated or adding a curing agent. After curing, its molecular structure forms a three-dimensional network structure and cannot be melted or reshaped again, and has good high-temperature stability, and is suitable for high-temperature, high-strength and corrosion-resistant scenes.

[0079] The thermosetting resin is in a liquid or semi-solid state when it is not cured, and still has a certain plasticity after partial curing. It is only after the cross-linking is completed that it is completely cured to form a rigid structure.

[0080] In some embodiments, the thermosetting resin can be any one or more of epoxy resin, phenolic resin, unsaturated polyester, polyurethane, silicone resin and bismaleimide, which are not limited in the present application.

[0081] It can be understood that the thermosetting resin with the melting temperature between the first critical temperature value and the second critical temperature value can make the thermosetting resin in a flowable state at the ambient temperature at which the first plug material is in a high-elastic state, so as to facilitate the second plug.

[0082] In some embodiments, the second plug material in the flowable state is placed on the screen plate corresponding to the screen printing device at the same ambient temperature, and the second plug material is pushed into the through hole from the first end of the through hole by using the printing doctor blade, so that the second plug material gradually pushes out the first plug material in the high-elastic state.

[0083] Specifically, please refer to Figure 6 , Figure 6 is a process schematic diagram of the second plug of the plate to be processed.

[0084] In this embodiment, the second plug material 30 in the flowable state is placed on the screen plate 41 at the same ambient temperature, and the second plug material 30 is printed into the screen plate hole by the printing doctor blade 42, so that the second plug material 30 is pushed into the through hole 101 through the screen plate hole. Wherein, the printing doctor blade 42 is in contact with the screen plate 41 at a preset angle (for example, 60°-75°), and a preset pressure is applied, so that the second plug material 30 fills the screen plate hole under the pushing of the printing doctor blade 42, and is transferred to the through hole 101 through the screen plate hole. The second plug material 30 entering the through hole 101 pushes the first plug material 20 filled in the through hole 101 in the direction x from the first end to the second end under the plug pressure provided by the printing doctor blade 42, so as to gradually push out the first plug material 20.

[0085] Wherein, since the force is mutual, the first plug material 20 will reversely extrude the second plug material 30 in the direction y from the second end to the first end.

[0086] S26: after the second plug material fills the through hole, the second plug material is cured.

[0087] In this embodiment, after the second plug material completely pushes out the first plug material and fills the through hole, the second plug material is cured.

[0088] In some embodiments, the ambient temperature is raised to cure the second plug material.

[0089] In other embodiments, the second plug material is cured by ultraviolet light irradiation.

[0090] Specifically, please refer to Figure 7 , Figure 7 is a structural schematic diagram of an embodiment of the plate to be processed obtained in S26.

[0091] In the embodiment, the board to be processed 100 includes a plurality of core boards 11, and prepreg 12 is arranged between adjacent core boards 11. The core board 11 includes a dielectric layer 13 and copper layers 14 arranged on both sides of the dielectric layer 13. The board to be processed 100 includes at least one via hole 101, and the via hole 101 is filled with a second plug material 30. The outer side of the first end of the via hole 101 is formed with protruding second plug material 30.

[0092] S27: removing the second plug material protruding outside the via hole.

[0093] In the embodiment, the second plug material protruding outside the via hole is removed by brushing the board to obtain a circuit board.

[0094] It can be understood that during the plugging process, the second plug material may overflow outside the via hole and form protrusions or residues on the outer side surface of the via hole. Removing these protrusions can make the surface of the substrate flat, avoid affecting the subsequent process, and thus improve the functionality, reliability and process compatibility of the product.

[0095] Specifically, please refer to Figure 8 , Figure 8 is a structural schematic diagram of an embodiment of the circuit board of the present application.

[0096] In the embodiment, the circuit board 200 includes a plurality of core boards 11, and prepreg 12 is arranged between adjacent core boards 11. The core board 11 includes a dielectric layer 13 and copper layers 14 arranged on both sides of the dielectric layer 13. The circuit board 200 includes at least one via hole 101, and the via hole 101 is filled with a second plug material 30.

[0097] Among them, the second plug material 30 does not form a bubble cavity or forms a bubble cavity that is too small to be visible.

[0098] It can be understood that the double-sided pressing of the second plug material 30 by the plugging pressure and the extrusion pressure of the first plug material 20 acting on the second plug material 30 can further expel the remaining gas in the via hole 101 and the gas inside the second plug material 30, so that the filling of the second plug material 30 becomes continuous, thereby improving the plugging yield and the product yield of the circuit board 200.

[0099] Compared with the related art, the first plug material is used to plug the through hole for the first time, and the first plug material fills the through hole, so that the gas in the through hole is preliminarily discharged through the first plug material. Then, the second plug material is used to plug the through hole filled with the first plug material for the second time, so that the first plug material is pushed out by the second plug material, and the second plug material fills the through hole. The second plug material is double-pressurized by the plug pressure and the extrusion pressure of the first plug material acting on the second plug material in the opposite direction, so that the remaining gas in the through hole and the gas inside the second plug material are further discharged, thereby effectively reducing the probability of forming a cavity in the through hole, and then improving the plug yield and the product yield.

[0100] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A method of making a jack for a circuit board, comprising: The method comprises: obtaining a to-be-processed board, wherein the to-be-processed board comprises at least one through hole; performing first plugging on the through hole by using a first plugging material, and filling the through hole with the first plugging material; performing second plugging on the through hole filled with the first plugging material by using a second plugging material, so as to push out the first plugging material by the second plugging material and fill the through hole with the second plugging material.

2. The plugging method according to claim 1, wherein the step of performing first plugging on the through hole by using the first plugging material and filling the through hole with the first plugging material comprises: heating the first plugging material to be molten, and plugging the molten first plugging material into the through hole until the first plugging material fills the through hole; performing solidification treatment on the first plugging material in the through hole.

3. The plugging method according to claim 2, wherein the step of heating the first plugging material to be molten and plugging the molten first plugging material into the through hole until the first plugging material fills the through hole comprises: heating the first plugging material to a temperature above a first critical temperature value, so that the first plugging material is in a viscous flow state; plugging the first plugging material in the viscous flow state into the through hole until the first plugging material in the viscous flow state fills the through hole; the step of performing solidification treatment on the first plugging material in the through hole comprises: controlling the ambient temperature to be between the first critical temperature value and a second critical temperature value, so that the first plugging material plugged into the through hole is solidified and in an elastomeric state; wherein the second critical temperature value is lower than the first critical temperature value.

4. The plugging method according to claim 3, wherein the step of plugging the first plugging material in the viscous flow state into the through hole until the first plugging material in the viscous flow state fills the through hole comprises: plugging the first plugging material in the viscous flow state into the through hole by means of screen printing.

5. The plugging method according to claim 3, wherein after the step of performing solidification treatment on the first plugging material in the through hole, the method further comprises: removing the first plugging material protruding outside the through hole.

6. The plugging method according to claim 3, wherein the step of performing second plugging on the through hole filled with the first plugging material by using the second plugging material, so as to push out the first plugging material by the second plugging material and fill the through hole with the second plugging material comprises: plugging the second plugging material into the through hole filled with the first plugging material, so that the second plugging material gradually pushes out the first plugging material in the elastomeric state; after the second plugging material fills the through hole, performing solidification on the second plugging material.

7. The plugging method according to claim 6, wherein ​ ​ ​ ​ ​ The step of plugging the second plug material into the via filled with the first plug material to gradually push out the first plug material in the high-elastic state, comprises: The step of plugging the second plug material into the via filled with the first plug material to gradually push out the first plug material in the high-elastic state by screen printing at the same ambient temperature, comprises: The step of curing the second plug material after the second plug material is filled into the via, comprises: Removing the second plug material protruding outside the via.

8. The plug method according to claim 1, wherein: The thickness-diameter ratio of the via is greater than or equal to 6:

1.

9. The plug method according to claim 1, wherein: The first plug material comprises a thermoplastic resin, and the second plug material comprises a thermosetting resin.

10. A circuit board, characterized by The circuit board is manufactured by the plug method of any one of claims 1-9; wherein the circuit board comprises at least one via filled with the second plug material.

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