A method for manufacturing a multilayer circuit board

Abstract

This invention relates to a method for manufacturing a multilayer circuit board. The method includes: forming an initial multilayer circuit board; connecting target circuit layers, comprising the following steps: opening conductive vias from the top and / or bottom layers of the initial multilayer circuit board to the opposite side, wherein the conductive vias extend at least into a target circuit layer further from the initial location of the via; filling the conductive vias with a conductive material to form initial conductive vias; opening insulating vias at the initial conductive vias from the top and / or bottom layers of the initial multilayer circuit board to the opposite side, wherein the insulating vias extend at most into a target circuit layer further from the initial location of the vias; filling the insulating vias with an insulating material to form insulating vias; and forming a top circuit layer and a bottom circuit layer on one surface of the top layer and one surface of the bottom layer, respectively. The multilayer circuit board manufacturing method provided by this invention can achieve interlayer interconnection of any circuit layers, improve the freedom of circuit design, precisely control the via depth, and simplify the manufacturing process.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a method for manufacturing a multilayer circuit board. Background Technology

[0002] With technological advancements, electronic components are evolving towards higher density and integration. Multilayer board structures, through vertical signal conduction, save space and achieve higher signal density transmission. Furthermore, precise circuit design and layout can shorten signal transmission distances. Therefore, vertical interconnection in multilayer boards is crucial and a key method for improving signal density. Interlayer interconnection in multilayer boards is primarily achieved through via structures. For planar multilayer boards, one existing process involves laminating layers in stages according to the stack-up design before fabricating interconnect vias. This method is complex, inefficient, and cannot achieve interconnection between arbitrary circuit layers. Another method involves controlling the depth of vias on the laminated board before fabricating interconnect vias to achieve vertical interconnection. This method cannot precisely control the via depth and also cannot achieve interconnection between arbitrary circuit layers, especially when one layer is tightly attached to the laminate while the other is separated by other layers. For curved surfaces, current technology primarily focuses on surface circuitry, making interlayer interconnection even more challenging. For both planar and curved multilayer boards, current interlayer interconnection technologies struggle to achieve interlayer interconnection of arbitrary circuit layers, especially for interlayer interconnection of misaligned vias, which limits the freedom of circuit design.

[0003] Therefore, a manufacturing method for multilayer circuit boards is needed that can achieve interlayer interconnection of any circuit layer in the multilayer circuit board, with a simple process flow, small hole depth for each drilling, and precise control of hole depth. Summary of the Invention

[0004] Therefore, the present invention provides a method for manufacturing a multilayer circuit board to solve the problems of complex manufacturing process, low efficiency, inability to accurately control the opening depth, and inability to achieve interlayer interconnection of arbitrary circuit layers in the prior art, which leads to limited freedom of circuit design.

[0005] This invention provides a method for manufacturing a multilayer circuit board, comprising the following steps:

[0006] An initial multilayer circuit board is formed; multiple circuit layers, multiple board layers, and at least one lamination layer are laminated to form the initial multilayer circuit board; in the initial multilayer circuit board: the lamination layer or the board layer is between two adjacent circuit layers; there is a lamination layer between two adjacent board layers; there is a board layer between two adjacent lamination layers; and the top and bottom layers of the initial multilayer circuit board are both board layers;

[0007] Connecting target circuit layers, the target circuit layers including a first target circuit layer and a second target circuit layer, wherein the first target circuit layer and the second target circuit layer are any two circuit layers separated by at least one lamination layer; including the following steps:

[0008] Conductive openings are made from the top and / or bottom layers of the initial multilayer circuit board to the opposite side, and the conductive openings extend at least into the target circuit layer that is further away from the initial position of the opening.

[0009] The conductive opening is filled with a conductive material to form an initial conductive hole;

[0010] At the initial conductive via, an insulating opening is formed from the top and / or bottom layer of the initial multilayer circuit board to the opposite side, and the insulating opening extends at most into the target circuit layer that is closer to the initial position of the opening;

[0011] The insulating opening is filled with insulating material to form an insulating hole;

[0012] A top layer and a bottom layer are formed on the top and bottom surfaces of the initial multilayer circuit board, respectively.

[0013] Optionally, the number of layers of the first target line layer on the side opposite to the second target line layer is less than or equal to the number of layers of the second target line layer on the side opposite to the first target line layer.

[0014] When the number of layers on the side of the second target line layer facing the first target line layer is less than or equal to 1 / 2 of the total number of layers.

[0015] The target wiring layer includes a first target wiring layer and a second target wiring layer, wherein the first target wiring layer and the second target wiring layer are any two wiring layers separated by at least one layer of the lamination layer.

[0016] A conductive opening is formed in the top or bottom layer of the first target circuit layer in the initial multilayer circuit board on the side opposite to the second target circuit layer; the conductive opening penetrates the first target circuit layer and extends into the second target circuit layer.

[0017] The conductive opening is filled with a conductive material to form an initial conductive hole;

[0018] At the initial conductive hole, a new hole is drilled from the initial position of the initial conductive hole to penetrate into the first target circuit layer, forming an insulating hole; the diameter of the insulating hole is larger than the diameter of the conductive hole.

[0019] The insulating opening is filled with insulating material to form an insulating hole; the remaining initial conductive hole forms a target conductive hole, which connects the first target circuit layer and the second target circuit layer.

[0020] Optionally, the step of creating a conductive via on the top or bottom layer of the first target circuit layer in the initial multilayer circuit board, facing away from the second target circuit layer, further includes:

[0021] A conductive opening is formed from the top or bottom layer of the first target circuit layer on the side opposite to the second target circuit layer in the initial multilayer circuit board to the adjacent structural layer on the side opposite to the first target circuit layer of the second target circuit layer; the conductive opening penetrates the first target circuit layer and the second target circuit layer.

[0022] Optionally, the step of re-drilling a hole at the initial position of the initial conductive hole to penetrate into the first target circuit layer, forming an insulating hole; wherein the diameter of the insulating hole is larger than that of the conductive hole, includes:

[0023] At the initial conductive hole, a new hole is drilled from the initial position of the initial conductive hole to the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming an insulating hole; the diameter of the insulating hole is larger than the diameter of the conductive hole.

[0024] Optionally, the number of layers between the first target line layer and the top or bottom layer on the side opposite to the second target line layer is a layers;

[0025] The number of layers between the second target line layer and the top or bottom layer on one side of the first target line layer is n;

[0026] The maximum depth of the conductive opening is less than the thickness of n+2 structural layers, and the minimum depth is greater than the thickness of n structural layers.

[0027] The maximum depth of the insulating opening is less than the thickness of the a+1 layer and the minimum depth is greater than the thickness of the a-1 layer.

[0028] Optionally, the number of layers of the first target line layer on the side opposite to the second target line layer is less than or equal to the number of layers of the second target line layer on the side opposite to the first target line layer.

[0029] When the number of the layers on the side of the second target line layer facing the first target line layer is greater than 1 / 2 of the total number of layers.

[0030] The target wiring layer includes a first target wiring layer and a second target wiring layer, wherein the first target wiring layer and the second target wiring layer are any two wiring layers separated by at least one layer of the lamination layer.

[0031] Open through holes in the initial multilayer circuit board;

[0032] The via is filled with a conductive material to form an initial conductive via;

[0033] A new hole is drilled at the position of the initial conductive via on the side of the first target circuit layer opposite to the second target circuit layer, penetrating into the first target circuit layer to form a first insulating via; the diameter of the first insulating via is larger than the diameter of the via.

[0034] The first insulating opening is filled with insulating material to form the first insulating hole;

[0035] A second insulating opening is formed by re-drilling a hole at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, thus penetrating into the second target circuit layer; the diameter of the second insulating opening is larger than the diameter of the via.

[0036] The second insulating opening is filled with insulating material to form a second insulating hole;

[0037] The remaining initial conductive vias form target conductive vias, which connect the first target circuit layer and the second target circuit layer.

[0038] Optionally, the step of re-drilling a via into the first target circuit layer at the location of the initial conductive via on the side of the first target circuit layer opposite to the second target circuit layer to form a first insulating via; the step of having a diameter of the first insulating via larger than the diameter of the via includes:

[0039] A new hole is drilled at the location of the initial conductive via on the side of the first target circuit layer facing away from the second target circuit layer, extending into the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the via.

[0040] Optionally, the step of re-drilling a via at the position of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer to form a second insulating via, wherein the diameter of the second insulating via is larger than the diameter of the via, includes:

[0041] A second insulating opening is formed by re-drilling a hole at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, extending into the adjacent structural layer on the side of the second target circuit layer opposite to the first target circuit layer; the diameter of the second insulating opening is larger than the diameter of the via.

[0042] Optionally, the number of layers between the first target line layer and the top or bottom layer on the side opposite to the second target line layer is a layers;

[0043] The number of layers between the second target line layer and the top or bottom layer on the side opposite to the first target line layer is m layers;

[0044] The maximum depth of the first insulating opening is greater than the thickness of the a+1 layer and the minimum depth is greater than the thickness of the a-1 layer.

[0045] The maximum depth of the second insulating opening is greater than the thickness of the m+1 structural layer, and the minimum depth is greater than the thickness of the m-1 structural layer.

[0046] Optionally, the conductive material can be filled by electroplating or printing followed by curing;

[0047] The insulating material is filled by printing or by filling holes and then curing.

[0048] The conductive material is made of silver paste, copper paste, or gold paste.

[0049] The insulating material is made of resin or ink, etc.

[0050] Optionally, the material of the lamination layer is a prepreg or an insulating resin.

[0051] Optionally, the multilayer circuit board is a planar multilayer circuit board or a curved multilayer circuit board.

[0052] The technical solution of the present invention has the following advantages:

[0053] (1) The manufacturing method of the multilayer circuit board provided by the present invention, on the one hand, firstly, a multilayer circuit board is formed by lamination, and after connecting any two target circuit layers, a top circuit layer and a bottom circuit layer are formed. Only two laminations are needed to form a multilayer circuit board, which can simplify the manufacturing process of the multilayer circuit board and improve the process efficiency. On the other hand, by opening conductive openings from the top and / or bottom of the initial multilayer circuit board to the opposite side, the conductive openings penetrate at least to the target circuit layer with a longer distance from the initial position of the opening, and filling the conductive openings with conductive material to form initial conductive holes, and at the initial conductive holes, opening insulating openings from the top and / or bottom of the initial multilayer circuit board to the opposite side, the insulating openings penetrate at most to the target circuit layer with a shorter distance from the initial position of the opening, and filling the insulating openings with insulating material to form insulating holes, the opening depth can be smaller each time, so that the opening depth can be controlled more precisely. At the same time, the interconnection between any circuit layers can be realized, especially the interconnection between circuit layers separated by lamination layers, especially when one side is close to the lamination layer and the other side is separated by other layers, which improves the freedom of circuit design. Therefore, the manufacturing method of multilayer circuit boards provided by the present invention can realize interlayer interconnection of arbitrary circuit layers, improve the freedom of circuit design, and at the same time facilitate more precise control of aperture depth, simplify the manufacturing process of multilayer circuit boards, and improve process efficiency.

[0054] (2) In the manufacturing method of the multilayer circuit board provided by the present invention, when the number of board layers on the side of the second target circuit layer facing the first target circuit layer is less than or equal to 1 / 2 of the total number of board layers, the conductive opening is formed by opening a hole from the top or bottom layer of the first target circuit layer in the initial multilayer circuit board facing away from the second target circuit layer to the second target circuit layer or to the adjacent structural layer on the side of the second target circuit layer facing away from the first target circuit layer. The insulating opening is formed by re-opening a hole at the initial position of the initial conductive hole to the first target circuit layer or to the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer. In the manufacturing method of the multilayer circuit board provided by the present invention, both openings are made from the side with fewer layers from the top or bottom layer, so that the opening depth is smaller each time, and the opening depth can be controlled more precisely. At the same time, since the upper and lower limits of the conductive opening and the insulating opening are significantly different, the accuracy requirement for the hole depth can be reduced, thereby improving the opening efficiency and realizing the interlayer interconnection of any circuit layer, thus improving the freedom of circuit design.

[0055] (3) In the manufacturing method of the multilayer circuit board provided by the present invention, when the number of layers on the side of the second target circuit layer facing the first target circuit layer is greater than 1 / 2 of the total number of layers, the conductive opening is formed by opening a through hole in the initial multilayer circuit board, and the insulating opening is formed by first re-opening a hole at the position of the initial conductive through hole on the side of the first target circuit layer facing away from the second target circuit layer, penetrating into the first target circuit layer or penetrating into the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer to form a first insulating opening, and then re-opening a hole at the position of the initial conductive through hole on the side of the second target circuit layer facing away from the first target circuit layer. The newly opened via extends into the second target circuit layer or extends into an adjacent structural layer on the side of the second target circuit layer opposite to the first target circuit layer to form a second insulating via. In the manufacturing method of the multilayer circuit board provided by the present invention, the method of opening the via does not require a specific opening depth. The opening of both the first insulating via and the second insulating via is performed from the side with a smaller distance from the top or bottom layer, resulting in a smaller opening depth each time. This allows for more precise control of the opening depth. At the same time, the upper and lower limits of the conductive via and the insulating via in this solution differ significantly, which can reduce the precision requirement for the hole depth, thereby improving the opening efficiency and enabling interlayer interconnection of any circuit layer, thus increasing the freedom of circuit design. Attached Figure Description

[0056] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0057] Figure 1A and Figure 1B This is a schematic diagram of a manufacturing method for multilayer boards in the prior art;

[0058] Figure 2A and Figure 2B A schematic diagram of a multilayer board that cannot be manufactured using existing technology;

[0059] Figure 3 This is a schematic flowchart of a method for manufacturing a multilayer circuit board according to an embodiment of the present invention.

[0060] Figure 4 This is a schematic diagram illustrating the specific process of a method for manufacturing a multilayer circuit board according to an embodiment of the present invention.

[0061] Figures 5A-5E This is a schematic diagram of the steps in a method for manufacturing a multilayer circuit board according to an embodiment of the present invention.

[0062] Figure 6 This is a schematic diagram illustrating the specific process of another method for manufacturing a multilayer circuit board according to an embodiment of the present invention.

[0063] Figures 7A-7F This is a schematic diagram of the steps in another method for manufacturing a multilayer circuit board according to an embodiment of the present invention.

[0064] Explanation of reference numerals in the attached figures:

[0065] 1-First board layer; 2-Second board layer; 3-Third board layer; 11-First circuit layer; 12-Second circuit layer; 13-Third circuit layer; 14-Fourth circuit layer; 15-Fifth circuit layer; 100-First lamination layer; 200-Second lamination layer; 101A-Conductive opening; 101B-Conductive opening; 102A-Initial conductive hole; 102B-Initial conductive hole; 103-Through hole; 104-Conductive through hole; 201A-Insulating opening; 201B-Insulating opening; 202A-Insulating hole; 202B-Insulating hole; 203A-Second insulating opening; 203B-Second insulating opening; 204A-Second insulating hole; 204B-Second insulating hole; 205A-First insulating opening; 205B-First insulating opening; 206A-First insulating hole; 206B-First insulating hole. Detailed Implementation

[0066] In existing processes, there are two methods for manufacturing multilayer boards. The first method is as follows: Figure 1A As shown, interconnection of two-layer circuits on a single board can be achieved: after opening through holes in the first board layer 1, metal is electroplated to interconnect the first circuit layer 11 and the second circuit layer 12; the interconnection of the third circuit layer 13 and the fourth circuit layer 14 is achieved in the same way. Another method is as follows... Figure 1B As shown, after the first layer 1 and the second layer 2 are laminated together, the laminated board is cleaned and the through holes are opened, and then electroplated to realize the interconnection between the first circuit layer 11 and the third circuit layer 13. The interconnection between the second circuit layer 12 and the fourth circuit layer 14 is similar.

[0067] Current technology can only interconnect circuit layers on both sides of the same board layer, and interconnect circuit layers on one side of the top or bottom layer with other circuit layers. However, when the circuit layers to be interconnected are located on both sides of the lamination layer, or when there are many interlayers, it is not possible to interconnect from one side of the lamination layer to the other side of the inner board. For example, as... Figure 2A In this case, interconnection between the second line layer 12 and the third line layer 13 cannot be achieved; for example... Figure 2BIn this context, interconnection between the second circuit layer 12 and the third circuit layer 13, the fourth circuit layer 14 and the fifth circuit layer 15, the second circuit layer 12 and the fifth circuit layer 15, or the third circuit layer 13 and the fifth circuit layer 15 cannot be achieved. Therefore, the existing technology cannot achieve interconnection between arbitrary circuit layers, especially the interconnection of circuit layers separated by lamination layers, particularly when one layer is in close contact with the lamination layer and the other layer is separated by other layers.

[0068] To address the problems of complex manufacturing processes, low efficiency, inability to precisely control aperture depth, and inability to achieve interlayer interconnection of arbitrary circuit layers in existing multilayer circuit board technologies, which limit the freedom of circuit design, this invention provides a method for manufacturing a multilayer circuit board, comprising: forming an initial multilayer circuit board; laminating multiple circuit layers, multiple board layers, and at least one laminating layer to form the initial multilayer circuit board; wherein in the initial multilayer circuit board: the laminating layer or the board layer is between two adjacent circuit layers; a laminating layer is between two adjacent board layers; a board layer is between two adjacent laminating layers; and the top and bottom layers of the initial multilayer circuit board are both board layers; connecting target circuit layers, the target circuit layers including a first target circuit layer and a second target circuit layer. The first target circuit layer and the second target circuit layer are any two circuit layers separated by at least one lamination layer; the method includes the following steps: opening conductive openings from the top and / or bottom layers of the initial multilayer circuit board to the opposite side, wherein the conductive openings extend at least into the target circuit layer at a distance longer than the initial opening position; filling the conductive openings with conductive material to form initial conductive holes; opening insulating openings from the top and / or bottom layers of the initial multilayer circuit board to the opposite side at the initial conductive holes, wherein the insulating openings extend at most into the target circuit layer at a shorter distance than the initial opening position; filling the insulating openings with insulating material to form insulating holes; and forming a top circuit layer and a bottom circuit layer on one surface of the top layer and one surface of the bottom layer of the initial multilayer circuit board, respectively.

[0069] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0070] Example 1

[0071] like Figure 3 As shown, this embodiment provides a method for manufacturing a multilayer circuit board, including the following steps:

[0072] S101, forming an initial multilayer circuit board; laminating multilayer circuit layers, multilayer board layers, and at least one laminating layer to form the initial multilayer circuit board; in the initial multilayer circuit board: the space between two adjacent circuit layers is the laminating layer or the board layer; the space between two adjacent board layers is a laminating layer; the space between two adjacent laminating layers is a board layer; and the top and bottom layers of the initial multilayer circuit board are both board layers;

[0073] S102, Connecting the target circuit layer, the target circuit layer includes a first target circuit layer and a second target circuit layer, the first target circuit layer and the second target circuit layer being any two circuit layers separated by at least one lamination layer; including the following steps:

[0074] S102-1, Conductive openings are made from the top and / or bottom layers of the initial multilayer circuit board to the opposite side, and the conductive openings extend at least into the target circuit layer that is further away from the initial position of the openings.

[0075] S102-2, Fill the conductive opening with a conductive material to form an initial conductive hole;

[0076] S102-3, at the initial conductive via, an insulating opening is made from the top and / or bottom layer of the initial multilayer circuit board to the opposite side, and the insulating opening extends at most into the target circuit layer that is closer to the initial position of the opening;

[0077] S102-4, Fill the insulating opening with insulating material to form an insulating hole;

[0078] S103, a top layer and a bottom layer are formed on the top surface and the bottom surface of the initial multilayer circuit board, respectively.

[0079] In practice, the hole-making method can be etching, using mechanical drilling equipment, or other methods. This embodiment does not limit this method.

[0080] The manufacturing method of the multilayer circuit board provided by this invention, on the one hand, firstly laminates to form an initial multilayer circuit board, and after connecting any two target circuit layers, then forms a top circuit layer and a bottom circuit layer. Only two laminations are needed to form the multilayer circuit board, which simplifies the manufacturing process and improves efficiency. On the other hand, by opening conductive openings from the top and / or bottom layers of the initial multilayer circuit board to the opposite side, with the conductive openings extending at least into a target circuit layer further from the initial opening position, and filling the conductive openings with conductive material to form initial conductive holes, and then opening insulating openings at the initial conductive holes from the top and / or bottom layers of the initial multilayer circuit board to the opposite side, with the insulating openings extending at most into a target circuit layer further from the initial opening position, and filling the insulating openings with insulating material to form insulating holes, the depth of each opening can be smaller, allowing for more precise control of the opening depth. Simultaneously, it enables interlayer interconnection of any circuit layer, especially interconnection between circuit layers separated by lamination layers, particularly when one layer is tightly attached to the lamination layer while the other is separated by other layers, thus increasing the freedom of circuit design. Therefore, the manufacturing method of multilayer circuit boards provided in this embodiment can realize interlayer interconnection of any circuit layer, improve the freedom of circuit design, and at the same time facilitate more precise control of the hole depth, simplify the manufacturing process of multilayer circuit boards, and improve process efficiency.

[0081] Furthermore, in some embodiments, the number of layers of the first target line layer on the side opposite to the second target line layer is less than or equal to the number of layers of the second target line layer on the side opposite to the first target line layer.

[0082] When the number of layers on the side of the second target line layer facing the first target line layer is less than or equal to 1 / 2 of the total number of layers.

[0083] The target wiring layer includes a first target wiring layer and a second target wiring layer, wherein the first target wiring layer and the second target wiring layer are any two wiring layers separated by at least one layer of the lamination layer.

[0084] A conductive opening is formed in the top or bottom layer of the first target circuit layer in the initial multilayer circuit board on the side opposite to the second target circuit layer; the conductive opening penetrates the first target circuit layer and extends into the second target circuit layer.

[0085] The conductive opening is filled with a conductive material to form an initial conductive hole;

[0086] At the initial conductive hole, a new hole is drilled from the initial position of the initial conductive hole to penetrate into the first target circuit layer, forming an insulating hole; the diameter of the insulating hole is larger than the diameter of the conductive hole.

[0087] The insulating opening is filled with insulating material to form an insulating hole; the remaining initial conductive hole forms a target conductive hole, which connects the first target circuit layer and the second target circuit layer.

[0088] In practice, the circuit layer, board layer, and lamination layer are collectively referred to as structural layers. The number of layers on the side of the first target circuit layer facing away from the second target circuit layer includes the total number of all structural layers, such as the circuit layer, board layer, and lamination layer; the number of layers on the side of the second target circuit layer facing away from the first target circuit layer includes the total number of all structural layers, such as the circuit layer, board layer, and lamination layer.

[0089] The plate layer on the side of the second target line layer facing the first target line layer includes the plate layer between the second target line layer and the first target line layer, and also includes the plate layer on the side of the first target line layer facing away from the second target line layer.

[0090] The total number of layers refers to the total number of all layers in the initial multilayer circuit board.

[0091] Furthermore, in some embodiments, the step of creating a conductive via on the top or bottom layer of the first target circuit layer in the initial multilayer circuit board, facing away from the second target circuit layer, further includes:

[0092] A conductive opening is formed from the top or bottom layer of the first target circuit layer on the side opposite to the second target circuit layer in the initial multilayer circuit board to the adjacent structural layer on the side opposite to the first target circuit layer of the second target circuit layer; the conductive opening penetrates the first target circuit layer and the second target circuit layer.

[0093] Furthermore, in some embodiments, the step of re-drilling a hole at the initial position of the initial conductive hole to penetrate into the first target circuit layer, forming an insulating hole; wherein the diameter of the insulating hole is larger than that of the conductive hole, includes:

[0094] At the initial conductive hole, a new hole is drilled from the initial position of the initial conductive hole to the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming an insulating hole; the diameter of the insulating hole is larger than the diameter of the conductive hole.

[0095] Furthermore, in some embodiments, the number of layers between the first target line layer and the top or bottom layer on the side opposite to the second target line layer is 'a' layers.

[0096] The number of layers between the second target line layer and the top or bottom layer on one side of the first target line layer is n;

[0097] The maximum depth of the conductive opening is less than the thickness of n+2 structural layers, and the minimum depth is greater than the thickness of n structural layers.

[0098] The maximum depth of the insulating opening is less than the thickness of the a+1 layer and the minimum depth is greater than the thickness of the a-1 layer.

[0099] In the manufacturing method of the multilayer circuit board provided in this embodiment, when the number of layers on the side of the second target circuit layer facing the first target circuit layer is less than or equal to 1 / 2 of the total number of layers, the conductive opening is formed by opening a hole from the top or bottom layer of the first target circuit layer in the initial multilayer circuit board on the side away from the second target circuit layer, penetrating into the second target circuit layer or penetrating into an adjacent structural layer on the side of the second target circuit layer on the side away from the first target circuit layer. The insulating opening is formed by re-opening a hole at the initial position of the initial conductive hole, penetrating into the first target circuit layer or penetrating into an adjacent structural layer on the side of the first target circuit layer on the side away from the second target circuit layer. In the manufacturing method of the multilayer circuit board provided by this invention, both openings are made from the side with fewer layers from the top or bottom layer, so that the opening depth is smaller each time, and the opening depth can be controlled more precisely. At the same time, since the upper and lower limits of the conductive opening and the insulating opening are significantly different, the accuracy requirement for the hole depth can be reduced, thereby improving the opening efficiency, and thus realizing the interlayer interconnection of arbitrary circuit layers, increasing the freedom of circuit design.

[0100] Furthermore, in some embodiments, the number of layers of the first target line layer on the side opposite to the second target line layer is less than or equal to the number of layers of the second target line layer on the side opposite to the first target line layer.

[0101] When the number of the layers on the side of the second target line layer facing the first target line layer is greater than 1 / 2 of the total number of layers.

[0102] The target wiring layer includes a first target wiring layer and a second target wiring layer, wherein the first target wiring layer and the second target wiring layer are any two wiring layers separated by at least one layer of the lamination layer.

[0103] Open through holes in the initial multilayer circuit board;

[0104] The via is filled with a conductive material to form an initial conductive via;

[0105] A new hole is drilled at the position of the initial conductive via on the side of the first target circuit layer opposite to the second target circuit layer, penetrating into the first target circuit layer to form a first insulating via; the diameter of the first insulating via is larger than the diameter of the via.

[0106] The first insulating opening is filled with insulating material to form the first insulating hole;

[0107] A second insulating opening is formed by re-drilling a hole at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, thus penetrating into the second target circuit layer; the diameter of the second insulating opening is larger than the diameter of the via.

[0108] The second insulating opening is filled with insulating material to form a second insulating hole;

[0109] The remaining initial conductive vias form target conductive vias, which connect the first target circuit layer and the second target circuit layer.

[0110] In practice, after the initial conductive via is formed, there is no fixed order in which the first insulating via and the second insulating via are formed. The first insulating via can be formed first, or the second insulating via can be formed first.

[0111] In some embodiments, after forming the initial conductive via, firstly, a new via is drilled through the first target circuit layer to the first target circuit layer at the location of the initial conductive via on the side of the first target circuit layer opposite to the second target circuit layer, forming a first insulating via, and the first insulating via is filled with insulating material to form a first insulating hole; secondly, a new via is drilled through the second target circuit layer to the second target circuit layer at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, forming a second insulating via, and the second insulating via is filled with insulating material to form a second insulating hole; finally, the remaining initial conductive vias form target conductive vias, which connect the first target circuit layer and the second target circuit layer.

[0112] In other embodiments, after forming the initial conductive via, firstly, a new via is drilled through the second target circuit layer to the second target circuit layer at the location of the initial conductive via on the side opposite to the first target circuit layer, forming a second insulating via, and the second insulating via is filled with insulating material to form a second insulating hole; secondly, a new via is drilled through the first target circuit layer to the first target circuit layer at the location of the initial conductive via on the side opposite to the second target circuit layer, forming a first insulating via, and the first insulating via is filled with insulating material to form a first insulating hole; finally, the remaining initial conductive vias form target conductive holes, which connect the first target circuit layer and the second target circuit layer.

[0113] Furthermore, in some embodiments, the step of re-drilling a via into the first target circuit layer at the location of the initial conductive via on the side of the first target circuit layer opposite to the second target circuit layer to form a first insulating via; the step of having a diameter of the first insulating via larger than the diameter of the via includes:

[0114] A new hole is drilled at the location of the initial conductive via on the side of the first target circuit layer facing away from the second target circuit layer, extending into the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the via.

[0115] Furthermore, in some embodiments, the step of re-drilling a via at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer to form a second insulating via; the step of having a diameter of the second insulating via larger than the diameter of the via includes:

[0116] A second insulating opening is formed by re-drilling a hole at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, extending into the adjacent structural layer on the side of the second target circuit layer opposite to the first target circuit layer; the diameter of the second insulating opening is larger than the diameter of the via.

[0117] Furthermore, in some embodiments, the number of layers between the first target line layer and the top or bottom layer on the side opposite to the second target line layer is 'a' layers.

[0118] The number of layers between the second target line layer and the top or bottom layer on the side opposite to the first target line layer is m layers;

[0119] The maximum depth of the first insulating opening is greater than the thickness of the a+1 layer and the minimum depth is greater than the thickness of the a-1 layer.

[0120] The maximum depth of the second insulating opening is greater than the thickness of the m+1 structural layer, and the minimum depth is greater than the thickness of the m-1 structural layer.

[0121] In the manufacturing method of the multilayer circuit board provided in this embodiment, when the number of layers on the side of the second target circuit layer facing the first target circuit layer is greater than 1 / 2 of the total number of layers, the conductive opening is formed by creating a through-hole in the initial multilayer circuit board, and the insulating opening is formed by first creating a new hole at the position of the initial conductive through-hole on the side of the first target circuit layer facing away from the second target circuit layer, penetrating into the first target circuit layer or penetrating into an adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming a first insulating opening, and then creating a new hole at the position of the initial conductive through-hole on the side of the second target circuit layer facing away from the first target circuit layer. The second insulating aperture is formed by extending through the second target circuit layer or through the adjacent structural layer on the side of the second target circuit layer opposite to the first target circuit layer. In the manufacturing method of the multilayer circuit board provided in this embodiment, the aperture method has no requirement for the aperture depth. The first insulating aperture and the second insulating aperture are both made from the side with fewer layers away from the top or bottom layer, so that the aperture depth is smaller each time, and the aperture depth can be controlled more precisely. At the same time, the upper and lower limits of the conductive aperture and the insulating aperture in this solution are significantly different, which can reduce the accuracy requirement for the aperture depth, thereby improving the aperture efficiency and realizing the interlayer interconnection of any circuit layer, thus increasing the freedom of circuit design.

[0122] Furthermore, in some embodiments, the conductive material is filled by electroplating or printing followed by curing;

[0123] The insulating material is filled by printing or by filling holes and then curing.

[0124] The conductive material is made of silver paste, copper paste, or gold paste.

[0125] The insulating material is made of resin or ink;

[0126] In practice, the conductive material is a metal paste; in some specific embodiments, the conductive material is silver paste, copper paste, or gold paste. The insulating material is a pore-filling resin or a pore-filling ink.

[0127] Furthermore, in some embodiments, the thickness of the board layer is 500 μm, the thickness of the circuit layer is 50 μm, and the thickness of the lamination layer is 200 μm.

[0128] Furthermore, in some embodiments, the material of the laminate is a prepreg or an insulating resin.

[0129] Furthermore, in some embodiments, the multilayer circuit board is a planar multilayer circuit board or a curved multilayer circuit board.

[0130] Example 2

[0131] refer to Figure 4 and Figures 5A-5E This embodiment provides a specific process for manufacturing a multilayer circuit board, including steps S201-S203:

[0132] S201, forming an initial multilayer circuit board; laminating multiple circuit layers, multiple board layers, and at least one laminating layer to form the initial multilayer circuit board; in the initial multilayer circuit board: the space between two adjacent circuit layers is the laminating layer or the board layer; there is a laminating layer between two adjacent board layers; there is a board layer between two adjacent laminating layers; and the top and bottom layers of the initial multilayer circuit board are both board layers.

[0133] In one specific implementation, such as Figure 5A As shown, the initial multilayer circuit board sequentially includes a second circuit layer 12, a first board layer 1, a first lamination layer 100, a third circuit layer 13, and a second board layer 2.

[0134] S202, Connect the target circuit layer, the target circuit layer includes a first target circuit layer and a second target circuit layer, the first target circuit layer and the second target circuit layer are any two circuit layers separated by at least one layer of the lamination layer; the number of layers of the first target circuit layer on the side away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer on the side away from the first target circuit layer; the number of the board layers of the second target circuit layer on the side facing the first target circuit layer is less than or equal to 1 / 2 of the total number of the board layers.

[0135] In one specific implementation, such as Figure 5A As shown, the first target circuit layer is the second circuit layer 12, the second target circuit layer is the third circuit layer 13, and the number of boards facing the second circuit layer 12 in the third circuit layer 13 is 1 (i.e., the first board layer 1), which is equal to 1 / 2 of the total number of boards 2. The thickness of the board layer is 500μm, the thickness of the circuit layer is 50μm, and the thickness of the lamination layer is 200μm.

[0136] Step S202 includes steps S202-1 to S202-4.

[0137] S202-1, A conductive opening is formed by extending from the top or bottom layer of the first target circuit layer on the side opposite to the second target circuit layer in the initial multilayer circuit board to the second target circuit layer or to the adjacent structural layer on the side opposite to the first target circuit layer of the second target circuit layer.

[0138] In one specific implementation, such as Figure 5AAs shown, a conductive opening 101A or 101B is formed by an opening extending from the first board layer 1 into the third circuit layer 13 or into the second board layer 2. Conductive opening 101A has the minimum depth, and conductive opening 101B has the maximum depth, with n=3. The depth of the conductive opening is less than the thickness of 5 structural layers (2 board layers + 2 circuit layers + 1 lamination layer), which is 1300μm; the depth of the conductive opening is greater than the thickness of 3 structural layers (1 board layer + 1 circuit layer + 1 lamination layer), which is 750μm.

[0139] Preferably, the opening extends from the first board layer 1 to a position greater than half the thickness of the third circuit layer 13 or to a position less than half the thickness of the second board layer 2. That is, the depth of the conductive opening is less than the thickness of 4.5 structural layers (2 board layers + 1.5 circuit layers + 1 lamination layer), which is 1275 μm; the depth of the conductive opening is greater than the thickness of 3 structural layers (1.5 board layers + 1 circuit layer + 1 lamination layer), which is 500 μm.

[0140] S202-2, Fill the conductive opening with a conductive material to form an initial conductive hole.

[0141] In one specific implementation, such as Figure 5B As shown, conductive openings 101A or 101B are filled with conductive material to form initial conductive holes 102A or 102B.

[0142] S202-3, at the initial conductive hole, a new hole is drilled from the initial position of the initial conductive hole to penetrate into the first target circuit layer or into the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming an insulating hole; the diameter of the insulating hole is larger than the diameter of the conductive hole.

[0143] In one specific implementation, such as Figure 5C As shown, at the initial conductive via 102A or 102B, an insulating via 201A or 201B is formed by extending from the first board layer 1 into the second circuit layer 12 or into the first board layer 1. Insulating via 201A represents the maximum depth, and insulating via 201B represents the minimum depth, with a = 1. The depth of the insulating via is less than the thickness of two structural layers (one board layer + one circuit layer), which is 550 μm; the depth of the insulating via is greater than the thickness of one structural layer (one board layer), which is 0 μm.

[0144] Preferably, at the initial conductive hole 102A or 102B, the hole extends from the first board layer 1 to a position less than half the thickness of the second circuit layer 12, or extends to a position greater than half the thickness of the first board layer 1. That is, the hole depth of the insulating hole is less than the thickness of 1.5 structural layers (1 board layer + 0.5 circuit layer), which is 525 μm; the hole depth of the insulating hole is greater than the thickness of 0.5 structural layers (0.5 board layer), which is 250 μm.

[0145] S202-4, fill the insulating opening with insulating material to form an insulating hole; the remaining initial conductive hole forms a target conductive hole, which connects the first target circuit layer and the second target circuit layer.

[0146] In one specific implementation, such as Figure 5D As shown, insulating material is used to fill the insulating openings 201A or 201B to form insulating holes 202A or 202B; the remaining initial conductive holes form target conductive holes, which connect the first target circuit layer and the second target circuit layer.

[0147] S203, a top layer and a bottom layer are formed on the top surface and the bottom surface of the initial multilayer circuit board, respectively.

[0148] In one specific implementation, such as Figure 5E As shown, a first circuit layer 11 and a fourth circuit layer 14 are formed on the top and bottom surfaces of the initial multilayer circuit board, respectively. The first circuit layer 11 is the top circuit layer, and the fourth circuit layer 14 is the bottom circuit layer.

[0149] Example 3

[0150] refer to Figure 6 ,and Figures 7A to 7F This embodiment provides a specific process for another method of manufacturing a multilayer circuit board, including steps S301-S303:

[0151] S301, forming an initial multilayer circuit board; laminating multiple circuit layers, multiple board layers, and at least one laminating layer to form the initial multilayer circuit board; in the initial multilayer circuit board: the space between two adjacent circuit layers is the laminating layer or the board layer; there is a laminating layer between two adjacent board layers; there is a board layer between two adjacent laminating layers; and the top and bottom layers of the initial multilayer circuit board are both board layers.

[0152] In one specific implementation, such as Figure 7AAs shown, the initial multilayer circuit board sequentially includes a first board layer 1, a second circuit layer 12, a first lamination layer 100, a third circuit layer 13, a second board layer 2, a fourth circuit layer 14, a second lamination layer 200, a fifth circuit layer 15, and a third board layer 3.

[0153] S302, Connect the target circuit layer, the target circuit layer includes a first target circuit layer and a second target circuit layer, the first target circuit layer and the second target circuit layer are any two circuit layers separated by at least one layer of the lamination layer; the number of layers of the first target circuit layer on the side away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer on the side away from the first target circuit layer; the number of the board layers of the second target circuit layer on the side facing the first target circuit layer is greater than 1 / 2 of the total number of the board layers.

[0154] In one specific implementation, such as Figure 7A As shown, the first target circuit layer is the fifth circuit layer 15, the second target circuit layer is the third circuit layer 13, and the third circuit layer 13 has two layers facing the fifth circuit layer 15 (the second layer 2 and the third layer 3), which is greater than half of the total number of layers 3. The thickness of each layer is 500 μm, the thickness of each circuit layer is 50 μm, and the thickness of the lamination layer is 200 μm.

[0155] Step S302 includes steps S302-1 to S302-6.

[0156] S302-1, A through hole is opened in the initial multilayer circuit board.

[0157] In one specific implementation, such as Figure 7A As shown, a via 103 is formed in the initial multilayer circuit board.

[0158] S302-2, The through hole is filled with a conductive material to form an initial conductive through hole.

[0159] In one specific implementation, such as Figure 7B As shown, the through-hole 103 is filled with a conductive material to form an initial conductive through-hole 104.

[0160] S302-3, a second insulating opening is formed by re-drilling a hole at the position of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, extending into the second target circuit layer or into an adjacent structural layer on the side of the second target circuit layer opposite to the first target circuit layer; the diameter of the second insulating opening is larger than the diameter of the via.

[0161] In one specific implementation, such as Figure 7CAs shown, a second insulating aperture 203A or 203B is formed by re-drilling a hole at the initial conductive via location of the first board layer 1, penetrating into the third circuit layer 13 or the first lamination layer 100. The second insulating aperture 203A has the maximum depth, and the second insulating aperture 203B has the minimum depth, m = 3. The depth of the second insulating aperture is less than the thickness of the four structural layers (1 board layer + 2 circuit layers + 1 lamination layer), which is 800 μm; the depth of the second insulating aperture is greater than the thickness of the two structural layers (1 board layer + 1 circuit layer), which is 550 μm.

[0162] Preferably, a new hole is drilled at the position of the initial conductive via in the first plate layer 1, extending to a position less than half the thickness of the third circuit layer 13 or extending to a position greater than half the thickness of the first lamination layer 100. That is, the depth of the second insulating hole is less than the thickness of 3.5 structural layers (1 plate layer + 1.5 circuit layer + 1 lamination layer), which is 775 μm; the depth of the second insulating hole is greater than the thickness of 2.5 structural layers (1 plate layer + 1 circuit layer + 0.5 lamination layer), which is 650 μm.

[0163] S302-4, The second insulating opening is filled with insulating material to form a second insulating hole.

[0164] In one specific implementation, such as Figure 7D As shown, the second insulating opening 203A or 203B is filled with insulating material to form the second insulating hole 204A or 204B.

[0165] S302-5, a new hole is drilled at the position of the initial conductive via on the side of the first target circuit layer facing away from the second target circuit layer, penetrating into the first target circuit layer or into an adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the via.

[0166] In one specific implementation, such as Figure 7E As shown, a new via is drilled at the location of the initial conductive via in the third layer 3, penetrating into the fifth circuit layer 15 or into the third layer 3, forming a first insulating via 205A or 205B. The first insulating via 205A has the maximum depth, and the first insulating via 205B has the minimum depth, a = 1. The depth of the first insulating via is less than the thickness of two structural layers (one board layer + one circuit layer), which is 550 μm; the depth of the first insulating via is greater than the thickness of one structural layer (zero board layer), which is 0 μm.

[0167] Preferably, a new hole is drilled at the position of the initial conductive via in the third plate layer 3, extending to a position less than half the thickness of the fifth circuit layer 15 or extending to a position greater than half the thickness of the third plate layer 3. That is, the hole depth of the first insulating hole is less than the thickness of 1.5 structural layers (1 plate layer + 0.5 circuit layer), which is 525 μm; the hole depth of the first insulating hole is greater than the thickness of 0.5 structural layers (0.5 plate layer), which is 250 μm.

[0168] S302-6, the first insulating opening is filled with insulating material to form a first insulating hole; the remaining initial conductive vias form target conductive holes, which connect the first target circuit layer and the second target circuit layer.

[0169] In one specific implementation, such as Figure 7F As shown, the first insulating opening 205A or 205B is filled with insulating material to form the first insulating hole 206A or 206B; the remaining initial conductive holes form target conductive holes, which connect the first target circuit layer and the second target circuit layer.

[0170] S303, a top layer and a bottom layer are formed on the top surface and the bottom surface of the initial multilayer circuit board, respectively.

[0171] In one specific embodiment, a first circuit layer and a sixth circuit layer are formed on the top surface and the bottom surface of the initial multilayer circuit board, respectively. The first circuit layer is the top circuit layer, and the sixth circuit layer is the bottom circuit layer.

[0172] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for manufacturing a multilayer circuit board, characterized in that, Includes the following steps: An initial multilayer circuit board is formed; multiple circuit layers, multiple board layers, and at least one lamination layer are laminated to form the initial multilayer circuit board; in the initial multilayer circuit board: the lamination layer or the board layer is between two adjacent circuit layers; there is a lamination layer between two adjacent board layers; there is a board layer between two adjacent lamination layers; and the top and bottom layers of the initial multilayer circuit board are both board layers; Connect the target circuit layer, the target circuit layer includes a first target circuit layer and a second target circuit layer, the first target circuit layer and the second target circuit layer are any two circuit layers separated by at least one layer of the lamination layer; A top layer and a bottom layer are formed on the top surface and the bottom surface of the initial multilayer circuit board, respectively. Wherein, the number of layers of the first target line layer on the side opposite to the second target line layer is less than or equal to the number of layers of the second target line layer on the side opposite to the first target line layer. When the number of layers on the side of the second target line layer facing the first target line layer is less than or equal to 1 / 2 of the total number of layers, the step of connecting the target line layer includes: A conductive opening is formed in the top or bottom layer of the first target circuit layer in the initial multilayer circuit board on the side opposite to the second target circuit layer; the conductive opening penetrates the first target circuit layer and extends into the second target circuit layer. The conductive opening is filled with a conductive material to form an initial conductive hole; At the initial conductive hole, a new hole is drilled from the initial position of the initial conductive hole to penetrate into the first target circuit layer, forming an insulating hole; the diameter of the insulating hole is larger than the diameter of the conductive hole. The insulating opening is filled with insulating material to form an insulating hole; the remaining initial conductive hole forms a target conductive hole, which connects the first target circuit layer and the second target circuit layer. When the number of layers on the side of the second target line layer facing the first target line layer is greater than 1 / 2 of the total number of layers, the step of connecting the target line layer includes: Through-holes are made in the initial multilayer circuit board; The via is filled with a conductive material to form an initial conductive via; A new hole is drilled at the position of the initial conductive via on the side of the first target circuit layer opposite to the second target circuit layer, penetrating into the first target circuit layer to form a first insulating via; the diameter of the first insulating via is larger than the diameter of the via. The first insulating opening is filled with insulating material to form the first insulating hole; A second insulating opening is formed by re-drilling a hole at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, thus penetrating into the second target circuit layer; the diameter of the second insulating opening is larger than the diameter of the via. The second insulating opening is filled with insulating material to form a second insulating hole; the remaining initial conductive vias form target conductive holes, which connect the first target circuit layer and the second target circuit layer.

2. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, When the number of layers on the side of the second target line layer facing the first target line layer is less than or equal to 1 / 2 of the total number of layers. The top or bottom layer of the first target circuit layer in the initial multilayer circuit board, facing away from the second target circuit layer, is opened to form a conductive opening. The step of having the conductive aperture penetrate the first target circuit layer and extend into the second target circuit layer further includes: A conductive opening is formed from the top or bottom layer of the first target circuit layer on the side opposite to the second target circuit layer in the initial multilayer circuit board to the adjacent structural layer on the side opposite to the first target circuit layer of the second target circuit layer; the conductive opening penetrates the first target circuit layer and the second target circuit layer.

3. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, When the number of layers on the side of the second target line layer facing the first target line layer is less than or equal to 1 / 2 of the total number of layers. The method involves re-drilling a hole at the initial position of the initial conductive hole to penetrate into the first target circuit layer, thereby forming an insulating hole. The step of making the diameter of the insulating opening larger than that of the conductive opening includes: At the initial conductive hole, a new hole is drilled from the initial position of the initial conductive hole to the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming an insulating hole; the diameter of the insulating hole is larger than the diameter of the conductive hole.

4. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, When the number of layers on the side of the second target line layer facing the first target line layer is less than or equal to 1 / 2 of the total number of layers. The number of layers between the first target line layer and the top or bottom layer on the side opposite to the second target line layer is 'a'. The number of layers between the second target line layer and the top or bottom layer on one side of the first target line layer is n; The maximum depth of the conductive opening is less than the thickness of n+2 structural layers, and the minimum depth is greater than the thickness of n structural layers. The maximum depth of the insulating opening is less than the thickness of the a+1 layer and the minimum depth is greater than the thickness of the a-1 layer.

5. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, When the number of the layers on the side of the second target line layer facing the first target line layer is greater than 1 / 2 of the total number of layers. The first insulating opening is formed by re-drilling a hole at the position of the initial conductive via on the side of the first target circuit layer opposite to the second target circuit layer. The step of having a diameter greater than the diameter of the through hole includes: A new hole is drilled at the location of the initial conductive via on the side of the first target circuit layer facing away from the second target circuit layer, penetrating into the adjacent structural layer on the side of the first target circuit layer facing away from the second target circuit layer, forming a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the via.

6. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, When the number of the layers on the side of the second target line layer facing the first target line layer is greater than 1 / 2 of the total number of layers. The initial conductive via is re-drilled at the position of the second target circuit layer on the side opposite to the first target circuit layer, and a second insulating via is formed in the second target circuit layer. The step of having a diameter greater than that of the through hole includes: A second insulating opening is formed by re-drilling a hole at the location of the initial conductive via on the side of the second target circuit layer opposite to the first target circuit layer, extending into the adjacent structural layer on the side of the second target circuit layer opposite to the first target circuit layer; the diameter of the second insulating opening is larger than the diameter of the via.

7. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, When the number of the layers on the side of the second target line layer facing the first target line layer is greater than 1 / 2 of the total number of layers. The number of layers between the first target line layer and the top or bottom layer on the side opposite to the second target line layer is 'a'. The number of layers between the second target line layer and the top or bottom layer on the side opposite to the first target line layer is m layers; The maximum depth of the first insulating opening is greater than the thickness of the a+1 layer and the minimum depth is greater than the thickness of the a-1 layer. The maximum depth of the second insulating opening is greater than the thickness of the m+1 structural layer, and the minimum depth is greater than the thickness of the m-1 structural layer.

8. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, The conductive material is filled by electroplating or printing followed by curing. The insulating material is filled by printing or by filling holes and then curing. The conductive material is made of silver paste, copper paste, or gold paste. The insulating material is made of resin or ink.

9. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, The material of the lamination layer is a prepreg or insulating resin.

10. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that, The multilayer circuit board can be a planar multilayer circuit board or a curved multilayer circuit board.

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