CN111629513B - Multi-layer circuit board structure with through hole and blind hole and its making method - Google Patents

Abstract

The invention provides a multi-layer circuit board structure, which comprises a first multi-layer board and a second multi-layer board which are laminated with each other, wherein a lamination interface of the first multi-layer board and the second multi-layer board comprises an adhesion medium layer and a first solder mask layer, the multi-layer circuit board structure is provided with at least one through hole penetrating through each layer and at least one blind hole penetrating through the first multi-layer board, part of the first solder mask layer is exposed by the blind hole so as to carry out laser carving, a laser window is formed in the first solder mask layer, a circuit of the second multi-layer board can be further exposed, and the embedded arrangement of a surface mounting assembly is facilitated subsequently. The invention also provides a manufacturing method of the multi-layer circuit board structure.

Description

Multi-layer circuit board structure with both through holes and blind holes and its manufacturing method

technical field

The present invention relates to a circuit board structure and its manufacturing method, in particular to a multi-layer circuit board structure with both through holes and blind holes and its manufacturing method.

Background technique

With the miniaturization and high integration of electronic components, the demand for multi-layer circuit boards (referred to as multi-layer boards) of high-function circuits is increasing, and due to the prevalence of surface mount components (SMD), the circuit board pattern The shape becomes more and more complex. What's more, in the existing multi-layer circuit board structure, there is a need to change the SMD into an embedded design without protruding from the surface of the circuit board, which further increases the difficulty of designing and manufacturing the circuit board structure. How to overcome the foregoing problems is really worthy of consideration by those skilled in the art.

Contents of the invention

In view of this, the present invention proposes a multi-layer circuit board structure capable of embedding surface mount components and a manufacturing method thereof.

In order to achieve the above and other objects, the present invention provides a multilayer circuit board structure having both through holes and blind holes, which includes a first multilayer board, a second multilayer board, a second solder resist layer and a The fourth solder resist layer, the first multilayer board has a first substrate, a patterned first copper layer, a second copper layer and an adhesive dielectric layer, the first copper layer is formed on one side of the first substrate, The second copper layer is formed on the other side of the second substrate, and the adhesive medium layer is formed on the surface of the second copper layer; the second multilayer board has a second substrate, an imaged third copper layer, and an imaged fourth copper layer. Copper layer and a first solder resist layer, the third copper layer is formed on one side of the second substrate, the fourth copper layer is formed on the other side of the second substrate, the first solder resist layer at least partially covers the third copper layer, and the adhesive The dielectric layer is laminated on the surface of the first solder resist layer; the second solder resist layer at least partially covers the first copper layer, and the third solder resist layer at least partially covers the fourth copper layer; wherein, the multilayer circuit board structure further includes at least one through hole , which runs through the first copper layer, the first substrate, the second copper layer, the adhesive dielectric layer, the first solder resist layer, the third copper layer, the second substrate and the fourth copper layer, and the hole wall of the through hole is formed with a hole Copper, the hole copper is electrically connected to at least one of the first and second copper layers and at least one of the third and fourth copper layers; wherein, the multilayer circuit board structure further includes at least one blind hole, and the blind hole runs through the first The second solder resist layer, the first copper layer, the first substrate, the second copper layer and the adhesive medium layer, and the blind hole exposes a part of the first solder resist layer; wherein, the multi-layer circuit board structure further includes at least one laser opening The window is formed in the exposed first solder resist layer in the blind hole, and the laser opening penetrates the first solder resist layer to expose a part of the third copper layer; wherein, the blind hole is for embedding at least one surface mount Mounting components, laser opening is for the embedded surface mount components to form an electrical connection with the third copper layer.

In order to achieve the above and other objects, the present invention also provides a multilayer circuit board structure having both through holes and blind holes, which includes a first multilayer board, a second multilayer board, a second solder resist layer and A third solder resist layer; the first multilayer board has a first substrate, an imaged first copper layer and an adhesive dielectric layer, the first copper layer is formed on one side of the first substrate, and the adhesive dielectric layer is formed on The other side of the second substrate; the second multilayer board has a second substrate, an imaged third copper layer, an imaged fourth copper layer and a first solder resist layer, and the third copper layer is formed on the first layer On one side of the second substrate, the fourth copper layer is formed on the other side of the second substrate, the first solder resist layer at least partially covers the third copper layer, and the adhesive medium layer is laminated on the surface of the first solder resist layer; the second solder resist layer The first copper layer is at least partially covered, and the second solder resist layer is at least partially covered by the fourth copper layer; wherein, the multilayer circuit board structure further includes at least one through hole, which penetrates the first copper layer, the first substrate, the adhesive medium layer, the second A solder resist layer, a third copper layer, a second substrate, and a fourth copper layer, and hole copper is formed on the wall of the through hole, and the hole copper is electrically connected to at least one of the first copper layer and the third and fourth copper layers One; wherein, the multilayer circuit board structure further includes at least one blind hole, at least one blind hole penetrates the second solder resist layer, the first copper layer, the first substrate and the adhesive dielectric layer, and at least one blind hole exposes the first solder resist layer A part of the layer; the multilayer circuit board structure further includes at least one laser opening, which is formed in the exposed first solder resist layer in the blind hole, and the laser opening penetrates the first solder resist layer to make the third copper A part of the layer is exposed; wherein, the blind hole is for embedding at least one surface mount component, and the laser opening is for the embedded surface mount component to form an electrical connection with the third copper layer.

In order to achieve the above and other objects, the present invention also provides a method for making a multilayer circuit board structure, which includes the following steps:

(A) Provide a first multilayer board and a second multilayer board: the first multilayer board has a first substrate, a first copper layer and a second copper layer, and the first copper layer is formed on the first substrate On one side of the second substrate, the second copper layer is formed on the other side of the second substrate; the second multilayer board has a second substrate, a third copper layer and a fourth copper layer, and the third copper layer is formed on the second substrate On one side, the fourth copper layer is formed on the other side of the second substrate;

(B) Pre-treat the first and second multilayer boards: form an incompletely cured adhesive medium layer on the surface of the second copper layer, and form at least one through the first copper layer, the first multilayer board on the first multilayer board. The base plate, the second copper layer and the blind hole pre-hole of the adhesive medium layer; the third copper layer is imaged, and a first solder mask layer is formed on the surface of the third copper layer, and the first solder mask layer is completely cured;

(C) Combining the first and second multilayer boards: laminating the first and second multilayer boards, laminating the incompletely cured adhesive medium layer on the surface of the first solder resist layer, and making the The incompletely cured adhesive medium layer is completely cured;

(D) Forming through holes and image processing: forming at least one through the first copper layer, the first substrate, the second copper layer, the adhesive dielectric layer, the first solder resist layer, the third copper layer, the second substrate and the fourth through holes in the copper layer, and form hole copper on the hole wall of at least one through hole, so that the hole copper is electrically connected to at least one of the first and second copper layers and at least one of the third and fourth copper layers, and Image the first and fourth copper layers;

(E) Further forming the solder resist layer: respectively cover an incompletely cured second solder resist layer and an incompletely cured third solder resist layer on the first and fourth copper layers, and the second solder resist layer is further filled In the front hole of the blind hole;

(F) Forming a blind hole: removing the second solder resist layer in the pre-hole of the blind hole to form at least one through the second solder resist layer, the first copper layer, the first substrate, the second copper layer and the adhesive medium layer blind hole;

(G) Laser window opening and solder mask curing: use a laser engraving machine to form at least one laser window on the exposed first solder mask layer in the blind hole, and completely cure the second and third solder mask layers, Laser opening penetrates through the first solder resist layer to expose a part of the third copper layer.

In order to achieve the above and other objects, the present invention also provides a method for making a multilayer circuit board structure, which includes the following steps:

(A) providing a first multilayer board and a second multilayer board: the first multilayer board has a first substrate and a first copper layer, and the first copper layer is formed on one side of the first substrate; The multilayer board has a second substrate, a third copper layer and a fourth copper layer, the third copper layer is formed on one side of the second substrate, and the fourth copper layer is formed on the other side of the second substrate;

(B) Pretreat the first and second multilayer boards: form an incompletely cured adhesive dielectric layer on the surface of the first substrate opposite to the first copper layer, and form at least A blind via hole through the first copper layer, the first substrate and the adhesive medium layer; image the third copper layer, and form a first solder resist layer on the surface of the third copper layer, and make the first solder resist The layer is fully cured;

(C) Combining the first and second multilayer boards: laminating the first and second multilayer boards, laminating the incompletely cured adhesive medium layer on the surface of the first solder resist layer, and making the The incompletely cured adhesive medium layer is completely cured;

(D) Forming through holes and image processing: forming at least one through hole penetrating through the first copper layer, the first substrate, the adhesive medium layer, the first solder resist layer, the third copper layer, the second substrate and the fourth copper layer , and forming hole copper on the hole wall of at least one through hole, so that the hole copper is electrically connected to at least one of the first copper layer and the third and fourth copper layers, and the first and fourth copper layers are imaged;

(E) Further forming the solder resist layer: respectively cover an incompletely cured second solder resist layer and an incompletely cured third solder resist layer on the first and fourth copper layers, and the second solder resist layer is further filled In the front hole of the blind hole;

(F) Forming a blind hole: removing the second solder resist layer in the pre-hole of the blind hole to form at least one blind hole penetrating through the second solder resist layer, the first copper layer, the first substrate and the adhesive medium layer;

(G) Laser window opening and solder mask curing: use a laser engraving machine to form at least one laser window on the exposed first solder mask layer in the blind hole, and completely cure the second and third solder mask layers, At least one laser opening penetrates the first solder resist layer to expose a part of the third copper layer.

Through the above design, the multilayer circuit board structure of the present invention has both through holes and blind holes, and the blind holes can support the embedded arrangement of surface mount components, thereby meeting the needs of the industry.

Details about other functions and embodiments of the present invention are described as follows with reference to the accompanying drawings.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments described in this application. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the cross-sectional schematic diagram of the first embodiment of multilayer circuit board structure of the present invention;

2 is a schematic cross-sectional view of the first embodiment of the multilayer circuit board structure of the present invention after mounting surface mount components and packaging;

3A to 3D are schematic diagrams of the first multilayer board pretreatment process of the first embodiment of the multilayer circuit board structure of the present invention;

4A to 4C are schematic diagrams of the second multilayer board pretreatment process of the first embodiment of the multilayer circuit board structure of the present invention;

5 to 12 are schematic diagrams of the manufacturing process of the first embodiment of the multilayer circuit board structure of the present invention;

13 is a schematic cross-sectional view of a second embodiment of the multilayer circuit board structure of the present invention;

FIG. 14 is a schematic cross-sectional view of a third embodiment of the multilayer circuit board structure of the present invention.

Symbol Description

10 surface mount components 100 multi-layer circuit board structure

101, 102 open window 110 the first multi-layer board

111 first substrate 112 first copper layer

113 second copper layer 114 adhesive dielectric layer

115 protective layer 116 blind hole front hole

120 second multilayer board 121 second substrate

122 third copper layer 123 fourth copper layer

124 first solder mask layer 130 second solder mask layer

140 third solder mask layer 150 through hole

151 hole copper 152 hole plug

160 blind hole 170 laser window

180, 181, 182 surface coating 200 multi-layer circuit board structure

210 first multilayer board 211 first substrate

212 first copper layer 214 adhesive dielectric layer

300 multi-layer circuit board structure 314 adhesive dielectric layer

3141 Adhesive layer 3142 Dielectric layer

3143 viscose

Detailed ways

The aforementioned and other technical content, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or back, etc., are only referring to the directions of the drawings. Accordingly, the directional terms used are for the purpose of illustration and not for the purpose of limiting the invention.

Please refer to Fig. 1 and Fig. 2, what is depicted is the first embodiment of the multilayer circuit board structure of the present invention, the multilayer circuit board structure 100 includes a first multilayer board 110, a second multilayer board 120, A second solder resist layer 130 and a third solder resist layer 140 .

The first multilayer board 110 has a first substrate 111 , an imaged first copper layer 112 , a second copper layer 113 and an adhesive dielectric layer 114 . The first substrate 111 is an electrical insulator, such as a dielectric, and in a possible implementation, the first substrate 111 is, for example, an FR-4 substrate. The first and second copper layers 112 and 113 are respectively formed on two opposite sides of the first substrate 111, and the first and second copper layers 112 and 113 may have patterned circuits; in a possible implementation, the second copper layer 113 may also not be graphed. The adhesive medium layer 114 is, for example, an electrical insulator with adhesive ability such as polypropylene and glue. Before the first and second multilayer boards 110, 120 are laminated to each other, the adhesive medium layer 114 is not completely cured, for example, the precursor is not fully cured. After the first and second multi-layer boards 110, 120 are laminated, the adhesive medium layer 114 is fully cured.

The second multilayer board 120 has a second substrate 121 , an imaged third copper layer 122 , an imaged fourth copper layer 123 and a first solder resist layer 124 . The second substrate 121 is also an electrical insulator, such as a dielectric, and in a possible implementation, the second substrate 121 is, for example, an FR-4 substrate. The third and fourth copper layers 122 and 123 are respectively formed on two opposite sides of the first substrate 121 , and the third and fourth copper layers 122 and 123 have patterned circuits. The first, second, and third solder resist layers 124 , 130 , 140 are used to protect the circuits on the multilayer circuit board structure 100 , prevent the circuits from being oxidized, and prevent the circuits from being polluted or damaged by subsequent processes. Wherein, the first solder resist layer 124 at least partially covers the third copper layer 122 to protect the image circuit of the third copper layer 122; the second solder resist layer 130 at least partially covers the first copper layer 112 to protect the first copper layer 112 Imaged circuit; the third solder resist layer 140 at least partially covers the fourth copper layer 123 to protect the imaged circuit of the fourth copper layer 123 .

The multilayer circuit board structure 100 also includes at least one through hole 150 (only one is shown in FIG. 1 as an example), which sequentially penetrates the first copper layer 112, the first substrate 111, the second copper layer 113, and the adhesive medium from top to bottom. Layer 114, the first solder resist layer 124, the third copper layer 122, the second substrate 121 and the fourth copper layer 123, the hole wall of the through hole 150 forms a hole copper 151, which is electrically connected to the first and second copper layers At least one of the layers 112 and 113 and at least one of the third and fourth copper layers 122 and 123 , that is, the via copper 151 can electrically connect circuits of different layers and different multilayer boards. In this embodiment, the through hole 150 is not covered by the second and third solder mask layers 130 and 140 . In other possible implementation manners, the through holes may also be covered by at least one of the second and third solder resist layers.

On the other hand, the multilayer circuit board structure 100 further includes at least one blind hole 160 (only one is shown in FIG. 1 as an example), which runs through the second solder resist layer 130, the first copper layer 112, the second A substrate 111 , a second copper layer 113 and an adhesive dielectric layer 114 expose a part of the first solder resist layer 124 . That is, the blind hole 160 runs through the first multilayer board 110 .

In addition, the multilayer circuit board structure 100 further includes at least one laser opening 170 (two are shown in FIG. 1 as an example), which is formed in the exposed first solder resist layer 124 in the blind hole 160, and the laser opening 170 penetrates The first solder resist layer 124 exposes a part of the third copper layer 122 . The laser opening 170 is formed, for example, by a laser engraving machine. In this embodiment, the hole wall of the blind hole 160 does not form hole copper, so the main purpose of opening the blind hole is not to connect multiple circuit layers (but it is not excluded in other possible implementations), but to provide embedded At least one surface mount component 10 (as shown in FIG. 2 ), such as a flip-chip LED. The top surface of the embedded surface mount component can be lower than, flush with or slightly higher than the top surface of the second solder mask layer as required. In order to facilitate the bonding of surface mount components, a surface coating 180 is formed on the exposed surface of the third copper layer 122 from the laser window, which can be but not limited to one of nickel, gold, silver, and palladium Or its laminated structure, such as electroplated nickel-gold laminated structure, electroplated nickel-silver-gold laminated structure, electroplated nickel-silver laminated structure, chemical nickel-gold laminated structure, chemical nickel-silver laminated structure or nickel-palladium-gold laminated structure.

One implementation of the manufacturing method of the multilayer circuit board structure is described below with the drawings.

First, a first multilayer board 110 and a second multilayer board 120 are provided; as shown in Figure 3A, the first multilayer board 110 has a first substrate 111, a first copper layer 112 and a second copper layer 113 , the first and second copper layers 112, 113 are respectively formed on two opposite sides of the first substrate 111; in addition, as shown in FIG. 4A, the second multilayer board 120 has a second substrate 121, a third copper layer 122 And a fourth copper layer 123, the third and fourth copper layers 122, 123 are respectively formed on two opposite sides of the second substrate 121; double-panel;

Next, the first and second multilayer boards 110, 120 are pretreated; as far as the first multilayer board 110 is concerned, as shown in Figure 3B, an incompletely cured adhesive medium layer is formed on the surface of the second copper layer 113 114, and form a protective layer 115 on the surface of the first copper layer 112, the sequence is not limited, if necessary, before the formation of the adhesive dielectric layer 114, the second copper layer 113 can be imaged by an etching process; then as shown As shown in 3C, at least one pre-blind hole 116 is formed on the first multilayer board 110 through the protective layer 115, the first copper layer 112, the first substrate 111, the second copper layer 112 and the adhesive dielectric layer 114, and then as follows As shown in FIG. 3D, the protective layer 115 is removed. The purpose of the protective layer 115 is to avoid or at least greatly reduce the burrs of the first copper layer 112 during the punching process; as for the second multilayer board 120, as shown in FIG. 4B As shown, image processing is performed on the third copper layer 122, and then as shown in FIG. 4C, a first solder resist layer 124 is formed on the surface of the third copper layer 122. The surface of the second substrate 121 exposed by chemical treatment. It should be noted that the pretreatment of the first and second multilayer boards can be carried out simultaneously or sequentially, and the sequence is not limited;

Next, combine the first and second multilayer boards 110 and 120; as shown in Figure 5, the first and second multilayer boards 110 and 120 are laminated, so that the incompletely cured adhesive medium layer 114 is laminated on the first and second multilayer boards 110 and 120. A surface of the solder resist layer 124, and make the adhesive medium layer 114 fully cured, for example, the adhesive medium layer is completely cured by thermal curing;

Then, forming through holes and image processing: as shown in FIG. The third copper layer 122, the second substrate 121 and the through hole 150 of the fourth copper layer 123; then, as shown in Figure 7, a copper layer is plated on the surface of the semi-finished multilayer circuit board by electroless plating, and then as shown in Figure 8 As shown, the unnecessary copper is removed by an etching process, and the hole copper 151 on the wall of the through hole 150 is retained and formed. At the same time, the first and fourth copper layers 112, 123 are imaged to form the required image circuit;

Next, further form the solder resist layer: as shown in Figure 9, first fill the hole plug 152 in the through hole 150, and then as shown in Figure 10, cover an incompletely cured copper layer 112 and 123 respectively The second solder resist layer 130 and an incompletely cured third solder resist layer 140, the second and third solder resist layers 130, 140 can be thermosetting, light curing or both thermosetting and light curing It is made of solder resist resin material with type characteristics, wherein the second solder resist layer 130 is further filled in the pre-blind hole 116, and then the hole plug 152 is removed;

Next, form blind holes: as shown in FIG. 11 , the second solder resist layer 130 in the blind hole pre-hole 116 is removed through lithography and etching processes to form the second solder resist layer 130, the first copper layer 112, the first substrate 111, the second copper layer 113, and the blind hole 160 of the adhesive dielectric layer 114, and at the same time form the openings 101, 102 at the positions where the first and fourth copper layers 112, 123 need to be exposed;

Then, laser window opening and solder mask curing: as shown in FIG. A part of the third copper layer 122 is exposed through the first solder resist layer 124; and the second and third solder resist layers 130, 140 are thermally cured and/or photocured (depending on their characteristics), so that both Complete curing; the order of laser window opening and solder mask curing is not limited, but in this embodiment, the solder mask layer is cured earlier than laser window opening.

Finally, if necessary, surface coatings 180, 181, 182 are respectively formed on the exposed surface of the third copper layer 122 from the laser opening 170 and at the openings 101, 102 to form the multilayer circuit board structure 100 shown in FIG. . After that, the placement and packaging process of surface mount components can be carried out to form a multi-layer circuit board structure as shown in Figure 2.

In other possible implementations, the first multilayer board can also be a single layer board, for example, in the second embodiment of the multilayer circuit board structure 200 shown in FIG. 13 , the first multilayer board 210 has no second copper layer, Therefore, the adhesive dielectric layer 214 is directly formed on the opposite side of the first substrate 211 to the first copper layer 212 , and the rest of the structure and process are not substantially different from those of the first embodiment.

In other possible implementations, the adhesive medium layer may be composed of multiple layers of medium. For example, in the third embodiment of the multilayer circuit board structure 300 shown in FIG. 14, the adhesive medium layer 314 includes an adhesive layer 3141 (Bonding Sheet), The dielectric layer 3142 (such as polyimide, PI) and the adhesive 3143 (Adhesive), but not limited to this combination.

The embodiments and/or implementations described above are only used to illustrate the preferred embodiments and/or implementations of the technology of the present invention, and are not intended to limit the implementation of the technology of the present invention in any form. Personnel, without departing from the scope of the technical means disclosed in the content of the present invention, may make some changes or modifications to other equivalent embodiments, but it should still be regarded as the technology or embodiment substantially the same as the present invention.

Claims (7)

1. A method of manufacturing a multi-layer circuit board structure, comprising the steps of:

A. providing a first multi-layer board and a second multi-layer board: the first multilayer board is provided with a first substrate, a first copper layer and a second copper layer, wherein the first copper layer is formed on one side of the first substrate, and the second copper layer is formed on the other side of the first substrate; the second multilayer board is provided with a second substrate, a third copper layer and a fourth copper layer, wherein the third copper layer is formed on one side of the second substrate, and the fourth copper layer is formed on the other side of the second substrate;

B. pretreating the first and second multilayer boards: forming an adhesive medium layer which is not completely cured on the surface of the second copper layer, and forming at least one blind hole preposed hole penetrating through the first copper layer, the first substrate, the second copper layer and the adhesive medium layer on the first multilayer board; imaging the third copper layer, forming a first solder mask layer on the surface of the third copper layer, and completely curing the first solder mask layer;

C. combining the first and second multilayer boards: laminating the first and second multilayer plates to laminate the non-cured adhesive medium layer on the surface of the first solder mask layer, and completely curing the non-cured adhesive medium layer;

D. forming a through hole and performing imaging treatment: forming at least one through hole penetrating the first copper layer, the first substrate, the second copper layer, the adhesion medium layer, the first solder mask layer, the third copper layer, the second substrate and the fourth copper layer, forming hole copper on the hole wall of the at least one through hole, enabling the hole copper to be electrically connected with at least one of the first copper layer and the second copper layer and at least one of the third copper layer and the fourth copper layer, and imaging the first copper layer and the fourth copper layer;

E. further forming a solder mask layer: covering a second incompletely cured solder mask layer and a third incompletely cured solder mask layer on the first copper layer and the fourth copper layer respectively, wherein the second solder mask layer is filled in the at least one blind hole preposed hole;

F. forming a blind hole: removing the second solder mask layer in the at least one blind hole front hole to form at least one blind hole penetrating through the second solder mask layer, the first copper layer, the first substrate, the second copper layer and the adhesion medium layer;

G. laser windowing and welding prevention layer curing: forming at least one laser window on the first solder mask layer exposed in the blind hole by using a laser engraving machine, and completely solidifying the second and third solder mask layers, wherein the at least one laser window penetrates through the first solder mask layer to expose a part of the third copper layer.

2. A method of manufacturing a multi-layer circuit board structure, comprising the steps of:

A. providing a first multi-layer board and a second multi-layer board: the first multilayer board is provided with a first substrate and a first copper layer, wherein the first copper layer is formed on one side of the first substrate; the second multilayer board is provided with a second substrate, a third copper layer and a fourth copper layer, wherein the third copper layer is formed on one side of the second substrate, and the fourth copper layer is formed on the other side of the second substrate;

B. pretreating the first and second multilayer boards: forming an adhesive medium layer which is not completely cured on the surface of one side of the first substrate opposite to the first copper layer, and forming at least one blind hole preposed hole penetrating the first copper layer, the first substrate and the adhesive medium layer on the first multilayer board; imaging the third copper layer, forming a first solder mask layer on the surface of the third copper layer, and completely curing the first solder mask layer;

C. combining the first and second multilayer boards: laminating the first and second multilayer plates to laminate the non-cured adhesive medium layer on the surface of the first solder mask layer, and completely curing the non-cured adhesive medium layer;

D. forming a through hole and performing imaging treatment: forming at least one through hole penetrating the first copper layer, the first substrate, the adhesion medium layer, the first solder mask layer, the third copper layer, the second substrate and the fourth copper layer, forming hole copper on the hole wall of the at least one through hole, enabling the hole copper to be electrically connected with at least one of the first copper layer and the third and fourth copper layers, and imaging the first and fourth copper layers;

E. further forming a solder mask layer: covering a second incompletely cured solder mask layer and a third incompletely cured solder mask layer on the first copper layer and the fourth copper layer respectively, wherein the second solder mask layer is filled in the at least one blind hole preposed hole;

F. forming a blind hole: removing the second solder mask layer in the at least one blind hole front hole to form at least one blind hole penetrating through the second solder mask layer, the first copper layer, the first substrate and the adhesion medium layer;

G. laser windowing and welding prevention layer curing: forming at least one laser window on the first solder mask layer exposed in the blind hole by using a laser engraving machine, and completely solidifying the second and third solder mask layers, wherein the at least one laser window penetrates through the first solder mask layer to expose a part of the third copper layer.

3. The method of claim 1 or 2, wherein in step B, a passivation layer is formed on the surface of the first copper layer before the formation of the at least one blind hole, and the at least one blind hole penetrates the passivation layer.

4. The method of claim 3, wherein the passivation layer is removed after the forming of the at least one blind via.

5. The method according to claim 1 or 2, wherein in the step G, the second and third solder masks are completely cured before the at least one laser window is formed.

6. The method of manufacturing a multi-layered circuit board structure according to claim 1 or 2, wherein a via plug is further filled in the via hole after the step D and before the step E, such that the second and third solder masks are not filled in the via hole.

7. The method according to claim 1 or 2, further comprising the step of forming a surface coating on the exposed surface of the third copper layer from the at least one laser window.

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