CN219876245U - circuit board - Google Patents

Abstract

The utility model provides a circuit board, relates to the technical field of electronic information, and is used for solving the technical problem that cross-layer blind holes are difficult to fill. The circuit board comprises at least two core plates, an outer layer plate and an adhesive layer, wherein the core plates are sequentially stacked, the outer layer plate is arranged on at least one side of the core plates, and the adhesive layer is arranged between the adjacent core plates and between the core plates and the outer layer plate; the circuit board is also provided with a first conductive column and a second conductive column which are opposite, the first conductive column at least penetrates through the bonding layer adjacent to the outer layer plate, the material of the first conductive column in the bonding layer is conductive paste, and the second conductive column is arranged in the outer layer plate. The conductive paste is used for filling holes of the bonding layer all the time, the drilling depth and the filling depth corresponding to the second conductive column are reduced, drilling and filling are facilitated, and the filling effect is good.

Description

Circuit board

Technical Field

The utility model relates to the technical field of electronic information, in particular to a circuit board.

Background

A circuit board (Printed Circuit Board, abbreviated as PCB) is one of the important components in various electronic products, and is a support for electronic components and a carrier for electrical connection in the electronic products, which has a great influence on the performance of the electronic products.

With miniaturization and integration of electronic products, circuit boards, particularly high density interconnect boards (High Density Interconnector, abbreviated as HDI), are continually moving toward higher multilayer, higher density. Circuit boards typically include a core board and an outer layer board disposed on at least one side of the core board, and to interconnect the layers in the circuit board, cross-layer blind vias are typically formed in the circuit board and filled using an electroplating hole filling process. However, the cross-layer blind vias of the circuit board tend to be difficult to fill.

Disclosure of Invention

In view of the above problems, an embodiment of the present utility model provides a circuit board for filling up a cross-layer blind hole of the circuit board.

In order to achieve the above object, the embodiment of the present utility model provides the following technical solutions:

the embodiment of the utility model provides a circuit board, which comprises at least two core boards, an outer layer board and an adhesive layer, wherein the at least two core boards are sequentially stacked, the outer layer board is arranged on at least one side of the core boards, and the adhesive layer is clamped between the adjacent core boards and between the core boards and the outer layer board;

the circuit board is also provided with a first conductive column and a second conductive column which are opposite, the first conductive column at least penetrates through the bonding layer adjacent to the outer layer plate, the first conductive column in the bonding layer is made of conductive slurry, and the second conductive column is arranged in the outer layer plate.

In some possible embodiments, the second conductive pillars are plated metal pillars.

In some possible embodiments, at least one end of the second conductive post remote from the core plate is exposed, and the second conductive post is directly opposite the first conductive post.

In some possible embodiments, the outer layer plate includes a first substrate, and first copper layers disposed on opposite sides of the first substrate, respectively;

the second conductive post penetrates through the first substrate and the first copper layer at one side far away from the core plate, and is in contact with the first copper layer at one side close to the core plate.

In some possible embodiments, the outer layer plate includes a first substrate, and a first copper layer disposed on a side of the first substrate remote from the core plate;

the second conductive post penetrates through the first substrate and the first copper layer and is in contact with the first conductive post.

In some possible embodiments, the first conductive post further extends into the core plate, the first conductive post including a first sub-post within the bonding layer, and a second sub-post within the core plate, the first sub-post and the second sub-post contacting opposite end faces of each other.

In some possible embodiments, the second pillar is a plated metal pillar.

In some possible embodiments, the number of the first conductive posts is plural, and at least part of the first conductive posts are different in length.

In some possible embodiments, the circuit board further comprises a third conductive post extending through each of the core plates, each of the adhesive layers, and the outer laminate, the third conductive post comprising a first filled core layer, and a first conductive layer disposed between the first filled core layer and the core plates, between the first filled core layer and the adhesive layers, between the first filled core layer and the outer laminate;

and/or the circuit board further comprises a fourth conductive post penetrating at least part of the core boards and the bonding layer between adjacent core boards, wherein the fourth conductive post comprises a second filling core layer and a second conductive layer arranged between the second filling core layer and the core boards, the second filling core layer and the bonding layer.

In some possible embodiments, the thickness of the adhesive layer is less than 150 μm;

and/or the core board comprises a second substrate and a second copper layer arranged on at least one side of the second substrate, wherein the thickness of the second copper layer is greater than or equal to 1oz.

In the circuit board provided by the embodiment of the utility model, at least the adjacent bonding layer of the outer layer plate is provided with the first conductive column, the first conductive column is conductive paste, and the outer layer plate is internally provided with the second conductive column correspondingly. On the one hand, in the lamination process of the outer layer plate and the core plate, the bonding layer is pressed and deformed, the outer layer plate and the core plate are bonded, the conductive paste deforms along with the bonding layer, holes of the bonding layer can be always filled, and the conductive paste and corresponding structures of the outer layer plate and the core plate are mutually sintered, so that the conductive performance between the outer layer plate and the core plate is ensured. On the other hand, the drilling depth and the filling depth corresponding to the second conductive column are reduced, drilling and filling are facilitated, and the filling effect is good.

In addition to the technical problems, technical features constituting the technical solutions, and beneficial effects caused by the technical features of the technical solutions described above, other technical problems that can be solved by the circuit board provided by the embodiment of the present utility model, other technical features included in the technical solutions, and beneficial effects caused by the technical features of the technical solutions, further detailed description will be made in the detailed description of the present utility model.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a circuit board according to an embodiment of the utility model;

fig. 2 is a schematic diagram of another structure of a circuit board according to an embodiment of the utility model;

FIG. 3 is a schematic illustration of an embodiment of the present utility model after forming an L3-4 layer core;

FIG. 4 is a schematic illustration of an embodiment of the present utility model after formation of an L4-5 tie layer;

FIG. 5 is a schematic diagram of an embodiment of the present utility model after forming the L3-8 layer;

FIG. 6 is a schematic diagram of a fourth conductive post formed according to an embodiment of the present utility model;

FIG. 7 is a schematic illustration of an embodiment of the present utility model after formation of an L2-3 tie layer;

FIG. 8 is a schematic illustration of an embodiment of the present utility model after forming an L1-2 ply.

Reference numerals illustrate:

10-outer laminate; 11-a first substrate;

12-a first copper layer; 20-core plate;

21-a second substrate; 22-a second copper layer;

30-a bonding layer; 40-first conductive pillars;

50-a second conductive post; 60-a third conductive post;

61-a first conductive layer; 62-a first filled core layer;

70-fourth conductive pillars; 71-a second conductive layer;

72-second filled core layer.

Detailed Description

In order to fill up the cross-layer blind holes, the circuit board in the embodiment of the utility model is provided with the first conductive columns in the bonding layers adjacent to the outer layer board, the first conductive columns are conductive paste, and the outer layer board is correspondingly provided with the second conductive columns. By utilizing the good filling performance and high-temperature sintering performance of the conductive paste, the first conductive column can be ensured to be always filled in the hole of the bonding layer and sintered with the conductive structures (such as the first copper layer or the second conductive column of the outer layer plate) at two sides of the bonding layer. Meanwhile, the second conductive column is only arranged in the outer layer plate, the corresponding drilling depth is reduced, the filling depth is reduced, drilling and filling are convenient, and the filling effect is good.

In order to make the above objects, features and advantages of the embodiments of the present utility model more comprehensible, the technical solutions of the embodiments of the present utility model will be described clearly and completely with reference to the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1, an embodiment of the present utility model provides a circuit board including at least two Core boards 20 (cores), an outer layer board 10, and an adhesive layer 30. Wherein, at least two core plates 20 are stacked in turn, and the outer layer plate 10 is disposed on at least one side of the core plates 20. Adhesive layers 30 are provided between adjacent core plates 20, and between the outer layer plates 10 and the core plates 20 adjacent thereto, so that at least two core plates 20 and the outer layer plates 10 form a single body while also ensuring insulation between adjacent plate members.

The core board 20 is a substrate of a circuit board, and the core board 20 may be a copper clad laminate (Copper Clad Laminate, abbreviated as CCL). The core plate 20 may be copper clad on one side or on both sides. In some examples, as shown in fig. 1, the core plate 20 includes a second substrate 21, and a second copper layer 22 disposed on at least one side of the second substrate 21. The material of the second substrate 21 may be a glass fiber cloth-based material, a paper-based material, a composite-based material, an aramid fiber nonwoven fabric-based material, a synthetic fiber-based material, or the like. The thickness of the second copper layer 22 is greater than or equal to 1oz.

When the second copper layer 22 is disposed on one side of the second substrate 21, the core 20 is a single-sided copper-clad plate, and the thickness of the second copper layer 22 may be 1oz or greater than 1oz. When the second copper layers 22 are disposed on both sides of the second substrate 21, the core 20 is a double-sided copper-clad plate, and the thickness of the second copper layers 22 on each side may be 0.5oz, 1oz or greater than 1oz, so that the sum of the thicknesses of the second copper layers 22 on both sides is greater than or equal to 1oz, i.e., the total thickness of the second copper layers 22 is greater than or equal to 1oz. The embodiments of the present utility model and the following embodiments are described by taking the core board 20 as a double-sided copper-clad plate as an example, and the double-sided copper-clad plate can improve the integration level of the circuit board.

An adhesive layer 30 is arranged between the adjacent core plates 20, and at least two core plates 20 are adhered into a whole by the adhesive layer 30 to form an inner layer structure of the circuit board. At least one side of the inner layer structure is provided with an outer layer plate 10, and the outer layer plate 10 and the adjacent core plate 20 are provided with an adhesive layer 30. As shown in fig. 1, 3 core plates 20 are bonded together by 2 adhesive layers 30, the adhesive layers 30 are provided above the core plates 20, and the outer layer plates 10 are provided on the adhesive layers 30. Wherein, the thickness of the bonding layer 30 is less than 150 μm, the bonding layer 30 can be prepreg, and the bonding layer 30 can also be epoxy glue layer, acrylic glue layer, etc.

One side of at least two core plates 20 is provided with outer laminate plates 10, i.e., the number of outer laminate plates 10 is one; or at least two core plates 20 are provided with outer laminate plates 10 on both sides, i.e., the number of outer laminate plates 10 is two. The outer laminate 10 may be a hard laminate or a soft laminate (Flexible Printed Circuits, abbreviated as FPC), and when the outer laminate 10 is a hard laminate, the adhesive layer 30 adjacent to the outer laminate 10 may be a prepreg; when the outer laminate 10 is a hard laminate, the adhesive layer 30 adjacent to the outer laminate 10 may be an epoxy adhesive layer, an acrylic adhesive layer. The outer laminate 10 may be a single-sided copper clad laminate or a double-sided copper clad laminate.

The outer layer board 10 includes a first substrate 11 and a first copper layer 12 disposed at least on one side of the first substrate 11, wherein the material of the first substrate 11 may be a flexible material such as polyimide or polyester. In some examples, as shown in fig. 1, the outer layer board 10 includes a first substrate 11, and first copper layers 12 disposed on opposite sides of the first substrate 11, respectively. In other examples, as shown in fig. 2, the outer laminate 10 includes a first substrate 11, and a first copper layer 12 disposed on a side of the first substrate 11 remote from the core 20.

To achieve an electrical connection between the outer laminate 10 and the core 20, the circuit board further includes oppositely disposed first and second conductive posts 40, 50. The second conductive post 50 is disposed inside the outer layer board 10, and at least one end of the second conductive post 50 away from the core board 20 is exposed, and the second conductive post 50 is opposite to the first conductive post 40, for example, the second conductive post 50 is located directly above the first conductive post 40. In some examples, the second conductive pillars 50 may be plated metal pillars, such as plated copper pillars, i.e., the outer plate 10 is filled up by a plating-and-hole process after being drilled.

The first conductive post 40 is disposed in the adhesive layer 30 adjacent to the outer laminate 10 and penetrates at least the adhesive layer 30 to be in contact with the outer laminate 10. The first conductive layer 61 is made of conductive paste, and the bonding layer 30 is deformed by compression and bonds the outer layer 10 and the core 20 in the lamination process of the outer layer 10 and the core 20 by utilizing good filling performance of the conductive paste, and the conductive paste can deform along with the bonding layer 30, so that holes of the bonding layer 30 are always filled, and the conductive performance between the outer layer 10 and the core 20 is ensured.

By providing the first conductive post 40 and the second conductive post 50, electrical connection between the outer layer board 10 and the core board 20 can be achieved, and filling of the cross-layer blind holes can be achieved. The first conductive stud 40 will be disposed only in the outer laminate 10 at Kong Tianping of the adhesive layer 30 adjacent to the outer laminate 10 and the second conductive stud 50 will have a corresponding hole depth less than or equal to the thickness of the outer laminate 10, i.e., the hole depth corresponding to the second conductive stud 50 will be reduced. On the one hand, the thickness of copper to be removed is reduced, drilling processing is facilitated, for example, drilling can be performed only through CO2 laser, copper opening by UV laser is not needed, and the problems of the capability and efficiency of the UV laser are overcome. On the other hand, the depth of the required filling hole is also reduced, the filling hole is convenient to fill, the filling effect is good, for example, a 1-order blind hole can be formed in the outer layer plate 10, the 1-order blind hole can be well filled by adopting an electroplating filling hole process, and the concave value of the electroplating filling hole is smaller than or equal to 25.4um.

In the embodiment in which the outer layer board 10 includes the first substrate 11 and the first copper layers 12 respectively disposed on opposite sides of the first substrate 11, as shown in fig. 1, the second conductive posts 50 penetrate the first substrate 11 and the first copper layers 12 on the side far from the core board 20 and are in contact with the first copper layers 12 on the side near the core board 20. It will be appreciated that the outer laminate 10 is provided with blind holes and that the second conductive studs 50 extend through the first copper layer 12 and the first substrate 11 on the side remote from the core 20 (upper side shown in fig. 1) to the first copper layer 12 on the side close to the core 20 (lower side shown in fig. 1), i.e. the second conductive studs 50 electrically connect the two first copper layers 12 of the outer laminate 10.

The outer layer plate 10 is electrically connected to the core plate 20 through the first conductive post 40, specifically, the first copper layer 12 near the core plate 20 contacts with the first conductive post 40, as shown in fig. 1, two sides of the first copper layer 12 near the core plate 20 contact with the upper end of the first conductive post 40 and the lower end of the second conductive post 50, that is, a space is formed between the first conductive post 40 and the second conductive post 50, and the second conductive post 50 is connected to the first conductive post 40 through the first copper layer 12 near the core plate 20.

In the embodiment in which the outer layer board 10 includes the first substrate 11 and the first copper layer 12 disposed on the side of the first substrate 11 away from the core board 20, as shown in fig. 2, the second conductive pillars 50 penetrate the first substrate 11 and the first copper layer 12 and are in contact with the first conductive pillars 40. I.e. the outer plate 10 is provided with a through hole and the second conductive stud 50 electrically connects the first copper layer 12 of the outer plate 10 with the first conductive stud 40.

In some embodiments, the first conductive post 40 penetrates through the adhesive layer 30 adjacent to the outer layer board 10, that is, the left side first conductive post 40 shown in fig. 1 is only disposed in the adhesive layer 30 adjacent to the outer layer board 10, two ends of the first conductive post 40 are respectively exposed at two sides of the adhesive layer 30, and the first conductive post 40 electrically connects the first copper layer 12 of the outer layer board 10 adjacent to the core board 20 and the core board 20.

In other embodiments, the first conductive posts 40 extend into the core 20, i.e., the first conductive posts 40 extend through at least one layer of the core 20, as shown in phantom in fig. 1. The first conductive post 40 includes a first sub-post located within the adhesive layer 30 and a second sub-post located within the core 20, the first and second sub-posts contacting opposite end surfaces of each other. Wherein the second pillar is a plated metal pillar, for example, the second pillar is a plated copper pillar.

The first conductive pillar 40 on the right side as viewed in fig. 1 includes a first pillar and a second pillar that are stacked in order, and when at least one of the first pillar and the second pillar has a plurality of pillars, the first pillar and the second pillar are alternately disposed.

For convenience of description, at least two core plates 20 are defined as a first core plate, a second core plate, … …, and an nth core plate, respectively, and at least two adhesive layers 30 are defined as a first adhesive layer, a second adhesive layer, … …, and an nth adhesive layer, respectively, in a direction away from the outer layer plate 10.

In some examples, the first conductive post 40 extends through one layer of the core board 20, i.e., the first conductive post 40 extends through the first core board, the first conductive post 40 may include a first leg extending through the first adhesive layer, and a second leg extending through the first core board, i.e., the first conductive layer 61 includes a first leg and a second leg. The first conductive posts 40 electrically connect the outer plate 10 with the first core plate.

Further, the first conductive post 40 may further include a first sub-post penetrating the second adhesive layer, that is, the first conductive layer 61 includes two first sub-posts and one second sub-post, and the first conductive post 40 electrically connects the outer layer board 10 with the first core board and the second core board.

In some embodiments, the number of first conductive posts 40 is plural, at least some of the first conductive posts 40 being different in length to achieve an electrical connection between the outer plate 10 and the different core plates 20. Illustratively, as shown in fig. 1, one first conductive post 40 of the plurality of first conductive posts 40 extends through the adhesive layer 30 adjacent the outer laminate 10, the first conductive post 40 electrically connecting the outer laminate 10 with one core 20 closest to the outer laminate 10, i.e., the outer laminate 10 is electrically connected with the first core. Another first conductive post 40 of the plurality of first conductive posts 40 penetrates through the two adhesive layers 30 and one core 20, the first conductive post 40 electrically connects the outer laminate 10 with one core 20 closest to the outer laminate 10 and one core 20 next to the outer laminate 10, i.e., the outer laminate 10, the first core and the second core.

With continued reference to fig. 1 and 2, the circuit board further includes third conductive posts 60 extending through each core 20, each adhesive layer 30, and the outer layer board 10, the third conductive posts 60 including a first filled core 62, and a first conductive layer 61 disposed between the first filled core 62 and the core 20, between the first filled core 62 and the adhesive layer 30, and between the first filled core 62 and the outer layer board 10.

As shown in fig. 1 and 2, the third conductive post 60 penetrates through the entire layer of the circuit board, a deep through hole is formed by mechanical drilling when the third conductive post 60 is manufactured, a first conductive layer 61 is formed by electroplating the wall of the deep through hole to a preset thickness, and a first filling core layer 62 is formed by filling resin into the deep through hole after the first conductive layer 61 is formed.

With continued reference to fig. 1 and 2, the circuit board further includes a fourth conductive post 70 extending through at least a portion of the core plates 20 and the adhesive layer 30 between adjacent core plates 20, the fourth conductive post 70 including a second filled core layer 72 and a second conductive layer 71 disposed between the second filled core layer 72 and the core plates 20, the second filled core layer 72 and the adhesive layer 30.

As shown in fig. 1 and 2, the fourth conductive pillars 70 are electrically connected to the adjacent plurality of core plates 20, and when the fourth conductive pillars 70 are fabricated, through holes are formed by mechanical drilling, the walls of the through holes are plated to a predetermined thickness to form the second conductive layer 71, and the through holes after the second conductive layer 71 is formed are filled with resin to form the second filling core layer 72.

In the manufacturing process of the circuit board in the embodiment of the utility model, the core boards 20 are bonded by the bonding layer 30, and the first conductive posts 40 are formed in the bonding layer 30 or the bonding layer 30 and the core board 20 in the bonding process. The outer laminate 10 is then placed over the outermost adhesive layer 30, with at least a portion of the first conductive stud 40 in the adhesive layer 30 adjacent the outer laminate 10. The outer layer plate 10 and each core plate 20 are bonded by press bonding to form a single body. Holes are drilled in the outer laminate 10 at positions opposite the first conductive posts 40 and filled with the second conductive posts 50.

The second conductive posts 50 in the outer plate 10 may be formed by laser drilling and plating-filling. The first conductive posts 40 in the adhesive layer 30 may be formed by laser drilling and leveling with a conductive paste. The first conductive posts 40 in the core 20 may be formed by laser drilling, or etching copper windows in combination with laser drilling, and plating and leveling.

By the arrangement, the electroplated metal columns in the core plate 20 and the columns after the conductive paste in the bonding layer 30 are solidified are overlapped to form the first conductive columns 40, and when the first conductive columns 40 are formed in the core plate 20 and the thickness of the second substrate 21 of the core plate 20 is smaller than 4mil, the problem of the depth control capability of mechanical drilling can be avoided; when the thickness of the second copper layer 22 of the core 20 is greater than 1oz, the UV laser copper opening capability problem can be avoided, thereby forming the higher first conductive pillars 40.

Alternatively, the third conductive post 60 may be formed within each core 20 and outer layer 10 and/or the fourth conductive post 70 may be formed in at least a portion of the core 20 after at least a portion of the core 20 is press bonded or after each core 20 is press bonded to the outer layer 10. Wherein the third conductive post 60 and/or the fourth conductive post 70 may be formed by mechanical drilling, electroplating via filling, resin via filling.

Referring to fig. 3 to 8, the manufacturing process of the circuit board is described by taking the circuit board including the three-layer core board 20, the three-layer adhesive layer 30 and one outer layer board 10 as an example, and the manufacturing process of the circuit board of other structures may refer to the manufacturing process of the circuit board in the following examples. Wherein the outer layer board 10 forms the L1-2 layer of the circuit board, the three layers of core boards 20 respectively form the L3-4, L5-6 and L7-8 layers of the circuit board along the direction far away from the outer layer board 10, and the three layers of bonding layers 30 respectively form the L4-5, L5-6 and L6-7 layers of the circuit board. The manufacturing process of the circuit board comprises the following steps:

portions of the first conductive posts 40 in the L3-4 layer core 20 are formed. Specifically, referring to FIG. 3, openings are formed in the L3-4 layer core 20 and electroplated filling holes are used to form portions of the first conductive posts 40 located in the L3-4 layer core 20. Wherein, the first conductive pillars 40 are copper pillars. When the copper thickness of the L3-4 layer core 20 is less than or equal to 0.5oz, CO is used ₂ Laser drilling; when the copper thickness of the L3-4 layer core 20 is greater than 0.5oz, etching is used to open the copper window, and then CO ₂ And (5) laser drilling.

The L4-5 adhesive layer 30 is drilled and filled with a conductive paste to form a portion of the first conductive pillars 40 located in the L4-5 adhesive layer 30. Specifically, referring to fig. 4, the L4 layer surface of the L3-4 layer core board 20 is pre-pressed with an adhesive sheet and a protective film (e.g., PET film) after the electroplating of the hole filling. The adhesive sheet forms an L4-5 layer adhesive layer 30, and CO is performed on the L4-5 layer adhesive layer 30 and the protective film ₂ And (3) laser drilling, filling and curing with the conductive paste, and removing the protective film to form part of the second conductive posts 50 in the L4-5 bonding layer 30. Wherein the aperture of the drilled hole can be set according to the requirement, and the processing condition of the conductive paste can be referred to the conductive pasteAnd the corresponding instruction.

An L3-8 layer plate is formed and a fourth conductive post 70 is formed. Specifically, referring to fig. 5, the L4-5 adhesive layer 30 is sequentially disposed on the side facing away from the L3-4 core plate 20, on the L5-6 core plate 20, on the adhesive sheet, on the L7-8 core plate 20, and the L3-4 core plate 20, the L4-5 adhesive layer 30, the L5-6 core plate 20, the adhesive sheet, and the L7-8 core plate 20 are laminated together to form an L3-8 plate, and on the adhesive sheet, the L6-7 adhesive layer 30 is formed. Referring to fig. 6, mechanical drilling is performed on the L3-8 layer plate to form a deeper through hole, and the deep through hole is communicated with the L3 layer, the L8 layer, and at least part of other layers between the L3 layer and the L8 layer, and then the electroplating is completed through the processes of washing with water under pressure, deburring, removing glue residues, depositing copper, electroplating and the like. And filling resin in the electroplated through holes, and performing curing and grinding treatment to enable the surfaces of the resin plug holes of the L3 layer and the L8 layer to be flat. And then manufacturing a line and a graph on the L3 layer.

An L2-3 adhesive layer 30 is formed on the side of the L3-4 core plate 20 facing away from the L4-5 adhesive layer 30, and the L2-3 adhesive layer 30 is drilled and filled with a conductive paste to form a portion of the first conductive pillars 40 located in the L2-3 adhesive layer 30. Specifically, referring to fig. 7, an adhesive sheet (e.g., a flexible adhesive sheet) and a protective film (e.g., a PET film) are pre-pressed on the surface of the L3 layer, the adhesive sheet forms an L2-3 adhesive layer 30, and the L2-3 adhesive layer 30 and the protective film are CO-laminated ₂ And (3) laser drilling, filling and curing with the conductive paste, and removing the protective film to form part of the first conductive posts 40 in the L2-3 bonding layer 30.

The L2-3 adhesive layer 30 is laminated with the L1-2 layer laminate 10 to form an L1-8 layer panel and a third conductive post 60, and to form a first conductive post 40 in the L1-2 layer laminate 10. Referring to FIG. 8, an L1-8 laminate is reduced in copper, browned, and CO laminated to an L1-2 laminate 10 ₂ Laser drilling, mechanical drilling on an L1-8 laminate piece, deburring and high-pressure water washing. Filling holes on the L1-2 layer laminate 10 by pre-plating and electroplating, filling holes on the L1-8 layer laminate piece by electroplating, filling holes on the resin, and curing and grinding to enable the surfaces of the L1 and L8 layer resin holes to be flat.

In summary, in the embodiment of the present utility model, at least the adjacent adhesive layer 30 of the outer layer board 10 is provided with the first conductive post 40, the first conductive post 40 is conductive paste, and the outer layer board 10 is correspondingly provided with the second conductive post 50. On the one hand, in the lamination process of the outer layer plate 10 and the core plate 20, the bonding layer 30 is pressed and deformed, and the outer layer plate 10 and the core plate 20 are bonded, and the conductive paste deforms along with the bonding layer 30, so that holes of the bonding layer 30 can be filled all the time, and the conductive paste and corresponding structures of the outer layer plate 10 and the core plate 20 are sintered mutually, so that the conductive performance between the outer layer plate 10 and the core plate 20 is ensured. On the other hand, the first conductive post 40 has reduced drilling depth and reduced filling depth, which is convenient for drilling and filling, and has better filling effect.

In this specification, each embodiment or implementation is described in a progressive manner, and each embodiment focuses on a difference from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model.

Claims (10)

1. A circuit board, comprising: at least two core plates, an outer layer plate and an adhesive layer, wherein the core plates are sequentially stacked, the outer layer plate is arranged on at least one side of the core plates, and the adhesive layer is clamped between the adjacent core plates and between the core plates and the outer layer plate;

the circuit board is also provided with a first conductive column and a second conductive column which are opposite, the first conductive column at least penetrates through the bonding layer adjacent to the outer layer plate, the first conductive column in the bonding layer is made of conductive slurry, and the second conductive column is arranged in the outer layer plate.

2. The circuit board of claim 1, wherein the second conductive posts are plated metal posts.

3. The circuit board of claim 1, wherein at least one end of the second conductive post remote from the core is exposed and the second conductive post is directly opposite the first conductive post.

4. The circuit board of claim 3, wherein the outer laminate comprises a first substrate and first copper layers disposed on opposite sides of the first substrate, respectively;

the second conductive post penetrates through the first substrate and the first copper layer at one side far away from the core plate, and is in contact with the first copper layer at one side close to the core plate.

5. The circuit board of claim 3, wherein the outer laminate comprises a first substrate and a first copper layer disposed on a side of the first substrate remote from the core;

the second conductive post penetrates through the first substrate and the first copper layer and is in contact with the first conductive post.

6. The circuit board of any one of claims 1-5, wherein the first conductive post further extends into the core plate, the first conductive post including a first leg within the adhesive layer and a second leg within the core plate, the first leg and the second leg contacting opposite end surfaces of each other.

7. The circuit board of claim 6, wherein the second stud is a plated metal stud.

8. The circuit board of claim 6, wherein the number of first conductive posts is plural, and at least some of the first conductive posts have different lengths.

9. The circuit board of any one of claims 1-5, further comprising a third conductive post extending through each of the core boards, each of the adhesive layers, and the outer laminate, the third conductive post comprising a first filled core layer, and a first conductive layer disposed between the first filled core layer and the core boards, between the first filled core layer and the adhesive layers, and between the first filled core layer and the outer laminate;

and/or the circuit board further comprises a fourth conductive post penetrating at least part of the core boards and the bonding layer between adjacent core boards, wherein the fourth conductive post comprises a second filling core layer and a second conductive layer arranged between the second filling core layer and the core boards, the second filling core layer and the bonding layer.

10. The circuit board of any one of claims 1-5, wherein the adhesive layer has a thickness of less than 150 μιη;

and/or the core board comprises a second substrate and a second copper layer arranged on at least one side of the second substrate, wherein the thickness of the second copper layer is greater than or equal to 1oz.