Manufacturing method of multilayer circuit board

Abstract

The invention relates to a manufacturing method of a multilayer circuit board. The manufacturing method comprises the following steps: forming an initial multilayer circuit board; the method is connected with a target circuit layer and comprises the following steps that a conductive hole is formed from the top layer and / or the bottom layer of the initial multilayer circuit board to the opposite side, and the conductive hole at least penetrates into the target circuit layer with the distance longer than the initial position of the hole; filling the conductive hole with a conductive material to form an initial conductive hole; insulating open holes are formed in the initial conductive holes from the top layer and / or the bottom layer of the initial multilayer circuit board to the opposite side, and the insulating open holes at most penetrate into a target circuit layer which is shorter away from the initial position of the open holes; filling the insulating hole with an insulating material to form an insulating hole; and respectively forming a top circuit layer and a bottom circuit layer on one side surface of the top layer and one side surface of the bottom layer. According to the manufacturing method of the multi-layer circuit board, interlayer interconnection of any circuit layer can be achieved, the freedom degree of circuit design is improved, the hole opening depth is accurately controlled, and the manufacturing technological process is simplified.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for manufacturing a multilayer circuit board. Background Art

[0002] With the development of technology, electronic components are developing towards high density and high integration. The multilayer board structure can save space and achieve higher density signal transmission through vertical signal conduction. At the same time, it can also achieve shorter signal transmission distance through line design and arrangement. Therefore, vertical interconnection of multilayer boards is crucial and an important means to improve signal density. The interlayer interconnection of multilayer boards is mainly achieved through hole structures. For planar multilayer boards, one method in the existing process is to laminate in batches according to the stacking design and then make interlayer interconnection through holes. This method has a complex process and low efficiency, and cannot achieve interconnection between any circuit layers; another method is to control the depth of the opening on the board after lamination and then make interconnection holes to achieve vertical interconnection. This method cannot accurately control the depth of the opening, and cannot achieve interconnection between any circuit layers, especially the interconnection of circuit layers separated by the laminated layer, especially when one side is close to the laminated layer and the other side is separated by other layers. As for curved surface processing, it is currently mainly used for surface circuits on curved surfaces, and interlayer interconnection is more difficult. For both flat multilayer boards and curved multilayer boards, the current interlayer interconnection process makes it difficult to achieve interlayer interconnection of any circuit layer, especially interlayer interconnection of staggered holes, which limits the freedom of circuit design.

[0003] Therefore, a method for manufacturing a multi-layer circuit board is needed, which can realize inter-layer interconnection of any circuit layer in the multi-layer circuit board, has a simple process flow, a small depth of each hole opening, and can accurately control the hole depth. Summary of the invention

[0004] Therefore, the present invention provides a method for manufacturing a multi-layer circuit board to solve the problems in the prior art that the manufacturing process of the multi-layer circuit board is complex, the efficiency is low, the opening depth cannot be accurately controlled, and the interlayer interconnection of any circuit layer cannot be achieved, resulting in limited freedom of circuit design.

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

[0006] Forming an initial multi-layer circuit board; Laminating multiple circuit layers, multiple board layers and at least one laminating layer to form the initial multi-layer circuit board; in the initial multi-layer circuit board: between two adjacent circuit layers is the laminating layer or the board layer; between two adjacent board layers is a laminating layer; between two adjacent laminating layers is a board layer; and the top layer and the bottom layer of the initial multi-layer circuit board are both the board layers;

[0007] Connecting target circuit layers, wherein the target circuit layers include 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 layer of the lamination layer; comprising the following steps:

[0008] Opening a conductive opening from the top layer and / or bottom layer of the initial multi-layer circuit board to the opposite side, wherein the conductive opening at least penetrates to the target circuit layer which is farther away from the initial position of the opening;

[0009] Filling the conductive opening with a conductive material to form an initial conductive hole;

[0010] At the initial conductive hole, an insulating opening is opened from the top layer and / or bottom layer of the initial multilayer circuit board to the opposite side, and the insulating opening at most penetrates to the target circuit layer which is shorter than the initial position of the opening;

[0011] Filling the insulating opening with insulating material to form an insulating hole;

[0012] A top wiring layer and a bottom wiring layer are respectively formed on one side surface of the top layer and one side surface of the bottom layer of the initial multi-layer wiring board.

[0013] Optionally, the number of layers of the first target circuit layer on a side facing away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer on a side facing away from the first target circuit layer;

[0014] When the number of the 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 the board layers,

[0015] The connecting 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, and include:

[0016] Opening a hole in the top layer or bottom layer of the first target circuit layer on the side facing away from the second target circuit layer in the initial multi-layer circuit board to form a conductive opening; the conductive opening penetrates the first target circuit layer and penetrates into the second target circuit layer;

[0017] Filling the conductive opening with a conductive material to form an initial conductive hole;

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

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

[0020] Optionally, the step of opening a hole in the top layer or bottom layer of the first target circuit layer in the initial multi-layer circuit board on the side facing away from the second target circuit layer to form a conductive opening; and the conductive opening passes through the first target circuit layer and passes through to the second target circuit layer, further includes:

[0021] A conductive opening is formed by opening a top layer or bottom layer on the side of the first target circuit layer in the initial multi-layer circuit board that is opposite to the second target circuit layer and extending through the structural layer adjacent to the side of the second target circuit layer that is opposite to the first target circuit layer; the conductive opening passes through the first target circuit layer and the second target circuit layer.

[0022] Optionally, the step of re-opening a hole from the initial opening position of the initial conductive hole to penetrate into the first target circuit layer to form an insulating opening; and the step of the insulating opening having a diameter larger than the conductive opening includes:

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

[0024] Optionally, the number of layers between the first target circuit layer and the top layer or the bottom layer on the side facing away from the second target circuit layer is a layers;

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

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

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

[0028] Optionally, the number of layers of the first target circuit layer on a side facing away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer on a side facing away from the first target circuit layer;

[0029] When the number of the board 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 the board layers,

[0030] The connecting 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, and include:

[0031] Opening a through hole in the initial multilayer circuit board;

[0032] Filling the through hole with a conductive material to form an initial conductive through hole;

[0033] A new hole is opened 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 to penetrate into the first target circuit layer to form a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the through hole;

[0034] Filling the first insulating opening with an insulating material to form a first insulating hole;

[0035] A new hole is opened 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 to penetrate into the second target circuit layer to form a second insulating opening; the diameter of the second insulating opening is larger than the diameter of the through hole;

[0036] Filling the second insulating opening with an insulating material to form a second insulating hole;

[0037] The remaining initial conductive vias form a target conductive via that connects the first target wiring layer and the second target wiring layer.

[0038] Optionally, the step of 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 to penetrate into the first target circuit layer to form a first insulating opening; and the diameter of the first insulating opening is larger than the diameter of the through hole, comprises:

[0039] A new hole is opened 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 to penetrate into the structural layer adjacent to the side of the first target circuit layer facing away from the second target circuit layer to form a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the through hole.

[0040] Optionally, the step of 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 to penetrate into the second target circuit layer to form a second insulating opening; and the diameter of the second insulating opening is larger than the diameter of the through hole, comprises:

[0041] A new hole is opened 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 to penetrate into the structural layer adjacent to the side of the second target circuit layer facing away from the first target circuit layer to form a second insulating opening; the diameter of the second insulating opening is larger than the diameter of the through hole.

[0042] Optionally, the number of layers between the first target circuit layer and the top layer or the bottom layer on the side facing away from the second target circuit layer is a layers;

[0043] The number of layers between the second target circuit layer and the top layer or the bottom layer on the side facing away from the first target circuit layer is m;

[0044] The maximum depth of the first insulating opening is greater than the thickness of the a+1 structural layer, and the minimum depth is greater than the thickness of the a-1 structural 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 is filled by electroplating or curing after printing;

[0047] The insulating material is filled by printing or plugging 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.

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

[0051] Optionally, the multi-layer circuit board is a planar multi-layer circuit board or a curved multi-layer 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 forms an initial multilayer circuit board by lamination, and then forms a top circuit layer and a bottom circuit layer after connecting any two target circuit layers. Only two laminations are required to form the 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 a conductive opening from the top and / or bottom layer of the initial multilayer circuit board to the opposite side, the conductive opening at least penetrates to the target circuit layer which is farther away from the initial position of the opening, and the conductive opening is filled with a conductive material to form an initial conductive hole, and at the initial conductive hole, an insulating opening is opened from the top and / or bottom layer of the initial multilayer circuit board to the opposite side, and the insulating opening at most penetrates to the target circuit layer which is farther away from the initial position of the opening, and the insulating opening is filled with an insulating material to form an insulating hole, which can make the depth of each opening smaller, so that the depth of the opening can be more accurately controlled, and at the same time, the interlayer interconnection of any circuit layer can be realized, especially the interconnection between circuit layers separated by the lamination layer can be realized, especially the situation where one side is close to the lamination layer and the other side is separated by other layers, thereby improving the freedom of circuit design. Therefore, the manufacturing method of the multilayer circuit board provided by the present invention can realize the interlayer interconnection of any circuit layer, improve the freedom of circuit design, and at the same time is conducive to more precise control of the opening depth, simplifying the manufacturing process of the multilayer circuit board, and improving the process efficiency.

[0054] (2) In the method for manufacturing a 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, a conductive opening is formed by opening a hole from the top or bottom layer of the first target circuit layer on the side facing away from the second target circuit layer in the initial multilayer circuit board, penetrating into the second target circuit layer or penetrating into the adjacent structural layer on the side of the second target circuit layer facing away from the first target circuit layer; and an insulating opening is formed by re-opening a hole from the initial position of the initial conductive hole at the initial conductive hole, 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; in the method for manufacturing a multilayer circuit board provided by the present invention, the two openings are both performed from the side with fewer layers away from the top or bottom layer, so that the depth of each opening is smaller, and the opening depth can be more accurately controlled. At the same time, since the upper and lower limits of the conductive openings and the insulating openings are greatly different, the accuracy requirements for the hole depth can be reduced, thereby improving the opening efficiency, thereby realizing interlayer interconnection of any circuit layer, and improving the degree of freedom of circuit design.

[0055] (3) In the manufacturing method of the multi-layer 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 greater than 1 / 2 of the total number of board layers, the conductive opening is formed by opening a through hole in the initial multi-layer circuit board, and the insulating opening is formed by first opening 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 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 opening 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 new hole is opened to penetrate into the second target circuit layer or to the structural layer adjacent to the second target circuit layer on the side facing away from the first target circuit layer to form a second insulating hole; in the manufacturing method of the multi-layer circuit board provided by the present invention, the method of opening the hole has no requirements on the hole depth, and the first insulating hole and the second insulating hole are opened from the side with fewer layers away from the top layer or the bottom layer, so that the hole depth is smaller each time, and the hole depth can be controlled more accurately. At the same time, the upper and lower limits of the conductive openings and the insulating openings in this scheme are greatly different, which can reduce the accuracy requirements on the hole depth, thereby improving the hole opening efficiency, and then realizing the interlayer interconnection of any circuit layer, and improving the freedom of circuit design. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0058] Figure 2A and Figure 2B A schematic diagram of the structure of a multilayer board that cannot be manufactured by the prior art;

[0059] Figure 3 A schematic flow chart of a method for manufacturing a multilayer circuit board according to an embodiment of the present invention;

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

[0061] Figure 5A-5E A schematic structural diagram of each step of a method for manufacturing a multilayer circuit board according to an embodiment of the present invention;

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

[0063] Figure 7A-7F The present invention is a structural schematic diagram of the steps of another method for manufacturing a multi-layer circuit board according to an embodiment of the present invention.

[0064] Description of reference numerals:

[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 pressing layer; 200-second pressing 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 DESCRIPTION

[0066] In the existing technology, there are two methods for manufacturing multilayer boards. Figure 1A As shown, the interconnection of the double-layer circuits of a single board can be realized: the first board layer 1 is electroplated with metal after a through hole is opened to realize the interconnection of the first circuit layer 11 and the second circuit layer 12, and the interconnection of the third circuit layer 13 and the fourth circuit layer 14 is similar. Figure 1B As shown, after the first board layer 1 and the second board layer 2 are laminated, the laminate is trimmed and opened with through holes and then electroplated to achieve interconnection between the first circuit layer 11 and the third circuit layer 13, and the second circuit layer 12 and the fourth circuit layer 14 are interconnected in the same way.

[0067] The current process can only realize the interconnection of circuit layers on both sides of the same board layer, and the interconnection of circuit layers on the top or bottom side with circuit layers on other layers. However, when the circuit layers to be interconnected are located on both sides of the laminate layer, and when there are many spacing layers, it is impossible to realize the interconnection from the laminate layer side to the inner layer side. Figure 2A In the example, the interconnection between the second circuit layer 12 and the third circuit layer 13 cannot be achieved; Figure 2BIn the embodiment, it is impossible to realize the 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. Therefore, the prior art cannot realize the interconnection between any circuit layers, especially the interconnection between circuit layers separated by the lamination layer, especially when one side is close to the lamination layer and the other side is separated by other layers.

[0068] In order to solve the problems in the prior art that the manufacturing process of multi-layer circuit boards is complicated, the efficiency is low, the opening depth cannot be accurately controlled, and the interlayer interconnection of any circuit layer cannot be achieved, resulting in limited freedom of circuit design, the present invention provides a method for manufacturing a multi-layer circuit board, including: forming an initial multi-layer circuit board; laminating multiple circuit layers, multiple board layers and at least one laminating layer to form the initial multi-layer circuit board; in the initial multi-layer circuit board: between two adjacent layers of the circuit layers is the laminating layer or the board layer; between two adjacent layers of the board layers is a layer of the laminating layer; between two adjacent layers of the laminating layer is a layer of the board layer; and the top layer and the bottom layer of the initial multi-layer circuit board are both the board layers; connecting target circuit layers, the target circuit layers include 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 laminated layer; comprising the following steps: opening a conductive opening from the top layer and / or the bottom layer of the initial multi-layer circuit board to the opposite side, the conductive opening at least penetrates to the target circuit layer which is farther away from the initial position of the opening; filling the conductive opening with a conductive material to form an initial conductive hole; at the initial conductive hole, opening an insulating opening from the top layer and / or the bottom layer of the initial multi-layer circuit board to the opposite side, the insulating opening at most penetrates to the target circuit layer which is farther away from the initial position of the opening; filling the insulating opening with an insulating material to form an insulating hole; forming a top circuit layer and a bottom circuit layer on one side surface of the top layer and one side surface of the bottom layer of the initial multi-layer circuit board, respectively.

[0069] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work 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 cannot be understood 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, comprising the following steps:

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

[0073] S102, connecting target circuit layers, wherein the target circuit layers include 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 layer of the lamination layer; comprising the following steps:

[0074] S102-1, opening a conductive opening from the top layer and / or bottom layer of the initial multi-layer circuit board to the opposite side, wherein the conductive opening at least penetrates to the target circuit layer which is farther away from the initial position of the opening;

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

[0076] S102-3, at the initial conductive hole, opening an insulating opening from the top layer and / or bottom layer of the initial multilayer circuit board to the opposite side, wherein the insulating opening at most penetrates to the target circuit layer that is shorter than the initial position of the opening;

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

[0078] S103, forming a top wiring layer and a bottom wiring layer on one side surface of the top layer and one side surface of the bottom layer of the initial multi-layer wiring board, respectively.

[0079] During specific implementation, the hole-making method may be etching, using a mechanical drilling device to make a hole, or other hole-making methods, which are not limited in this embodiment.

[0080] The manufacturing method of the multilayer circuit board provided by the present invention, on the one hand, firstly forms an initial multilayer circuit board by lamination, and then forms a top circuit layer and a bottom circuit layer after connecting any two target circuit layers, and only needs two laminations to form the 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 a conductive opening from the top layer and / or the bottom layer of the initial multilayer circuit board to the opposite side, the conductive opening at least penetrates to the target circuit layer with a longer distance from the initial position of the opening, and the conductive opening is filled with a conductive material to form an initial conductive hole, and at the initial conductive hole, an insulating opening is opened from the top layer and / or the bottom layer of the initial multilayer circuit board to the opposite side, and the insulating opening at most penetrates to the target circuit layer with a shorter distance from the initial position of the opening, and the insulating opening is filled with an insulating material to form an insulating hole, which can make the depth of each opening smaller, so that the depth of the opening can be more accurately controlled, and at the same time, the interlayer interconnection of any circuit layer can be realized, especially the interconnection between the circuit layers separated by the lamination layer can be realized, especially the situation where one side is close to the lamination layer and the other side is separated by other layers, thereby improving the freedom of circuit design. Therefore, the manufacturing method of the multi-layer circuit board provided in this embodiment can realize the inter-layer interconnection of any circuit layer, improve the freedom of circuit design, and at the same time is conducive to more precise control of the opening depth, simplifying the manufacturing process of the multi-layer circuit board, and improving process efficiency.

[0081] Further, in some embodiments, the number of layers of the first target circuit layer facing away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer facing away from the first target circuit layer;

[0082] When the number of the 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 the board layers,

[0083] The connecting 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, and include:

[0084] Opening a hole in the top layer or bottom layer of the first target circuit layer on the side facing away from the second target circuit layer in the initial multi-layer circuit board to form a conductive opening; the conductive opening penetrates the first target circuit layer and penetrates into the second target circuit layer;

[0085] Filling the conductive opening with a conductive material to form an initial conductive hole;

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

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

[0088] In specific implementation, 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 number of all structural layers such as circuit layers, board layers and lamination layers; the number of layers on the side of the second target circuit layer facing away from the first target circuit layer includes the number of all structural layers such as circuit layers, board layers and lamination layers.

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

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

[0091] Furthermore, in some embodiments, the step of opening a hole from the top layer or bottom layer of the first target circuit layer in the initial multi-layer circuit board on the side facing away from the second target circuit layer to form a conductive opening; and the conductive opening passes through the first target circuit layer and passes through the second target circuit layer, further includes:

[0092] A conductive opening is formed by opening a top layer or bottom layer on the side of the first target circuit layer in the initial multi-layer circuit board that is opposite to the second target circuit layer and extending through the structural layer adjacent to the side of the second target circuit layer that is opposite to the first target circuit layer; the conductive opening passes through the first target circuit layer and the second target circuit layer.

[0093] Furthermore, in some embodiments, the step of re-opening a hole from the initial opening position of the initial conductive hole to penetrate into the first target circuit layer to form an insulating opening; and the step of the insulating opening having a diameter larger than the conductive opening includes:

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

[0095] Further, in some embodiments, the number of layers between the first target circuit layer and the top layer or the bottom layer on the side facing away from the second target circuit layer is a layer;

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

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

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

[0099] In the manufacturing method of the multi-layer circuit board provided in the present embodiment, 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 layer or bottom layer on the side of the first target circuit layer facing away from the second target circuit layer in the initial multi-layer circuit board, penetrating into the second target circuit layer or penetrating into the adjacent structural layer on the side of the second target circuit layer facing away from the first target circuit layer, and the insulating opening is formed by re-opening a hole from the initial position of the opening of the initial conductive hole at the initial conductive hole, 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; in the manufacturing method of the multi-layer circuit board provided by the present invention, the two openings are both performed from the side with fewer layers away from the top layer or the bottom layer, so that the depth of each opening is smaller, and the depth of the opening can be more accurately controlled. At the same time, since the upper and lower limits of the conductive openings and the insulating openings are greatly different, the accuracy requirements for the hole depth can be reduced, thereby improving the opening efficiency, thereby realizing interlayer interconnection of any circuit layer, and improving the degree of freedom of circuit design.

[0100] Further, in some embodiments, the number of layers of the first target circuit layer facing away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer facing away from the first target circuit layer;

[0101] When the number of the board 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 the board layers,

[0102] The connecting 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, and include:

[0103] Opening a through hole in the initial multi-layer circuit board;

[0104] Filling the through hole with a conductive material to form an initial conductive through hole;

[0105] A new hole is opened 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 to penetrate into the first target circuit layer to form a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the through hole;

[0106] Filling the first insulating opening with an insulating material to form a first insulating hole;

[0107] A new hole is opened 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 to penetrate into the second target circuit layer to form a second insulating opening; the diameter of the second insulating opening is larger than the diameter of the through hole;

[0108] Filling the second insulating opening with an insulating material to form a second insulating hole;

[0109] The remaining initial conductive vias form a target conductive via that connects the first target wiring layer and the second target wiring layer.

[0110] In a specific implementation, after the initial conductive through hole is formed, there is no fixed order for forming the first insulating hole and the second insulating hole. The first insulating hole can be formed first, or the second insulating hole can be formed first.

[0111] In some embodiments, after the step of forming an initial conductive via, first, a new hole is opened 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 to penetrate into the first target circuit layer to form a first insulating opening, and the first insulating opening is filled with an insulating material to form a first insulating hole; secondly, a new hole is opened at the position of the initial conductive via on the side of the second target circuit layer facing away from the first target circuit layer to penetrate into the second target circuit layer to form a second insulating opening, and the second insulating opening is filled with an insulating material to form a second insulating hole; finally, the remaining initial conductive vias form target conductive holes, and the target conductive holes connect the first target circuit layer and the second target circuit layer.

[0112] In other embodiments, after the step of forming the initial conductive via, first, a new hole is opened at the position of the initial conductive via on the side of the second target circuit layer facing away from the first target circuit layer to penetrate into the second target circuit layer to form a second insulating opening, and the second insulating opening is filled with an insulating material to form a second insulating hole; secondly, a new hole is opened 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 to penetrate into the first target circuit layer to form a first insulating opening, and the first insulating opening is filled with an insulating material to form a first insulating hole; finally, the remaining initial conductive vias form target conductive holes, and the target conductive holes connect the first target circuit layer and the second target circuit layer.

[0113] Furthermore, in some embodiments, the step of 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 to penetrate into the first target circuit layer to form a first insulating opening; and the diameter of the first insulating opening is larger than the diameter of the through hole, comprises:

[0114] A new hole is opened 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 to penetrate into the structural layer adjacent to the side of the first target circuit layer facing away from the second target circuit layer to form a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the through hole.

[0115] Furthermore, in some embodiments, the step of 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 to penetrate into the second target circuit layer to form a second insulating opening; and the diameter of the second insulating opening is larger than the diameter of the through hole, comprises:

[0116] A new hole is opened 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 to penetrate into the structural layer adjacent to the side of the second target circuit layer facing away from the first target circuit layer to form a second insulating opening; the diameter of the second insulating opening is larger than the diameter of the through hole.

[0117] Further, in some embodiments, the number of layers between the first target circuit layer and the top layer or the bottom layer on the side facing away from the second target circuit layer is a layer;

[0118] The number of layers between the second target circuit layer and the top layer or the bottom layer on the side facing away from the first target circuit layer is m;

[0119] The maximum depth of the first insulating opening is greater than the thickness of the a+1 structural layer, and the minimum depth is greater than the thickness of the a-1 structural 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 multi-layer circuit board provided in the present embodiment, when the number of board 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 board layers, the conductive opening is formed by opening a through hole in the initial multi-layer circuit board, and the insulating opening is formed by first opening 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 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 opening 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 hole is opened through the second target circuit layer or through the structural layer adjacent to the second target circuit layer on the side facing away from the first target circuit layer to form a second insulating hole; in the manufacturing method of the multi-layer circuit board provided in this embodiment, the method of opening the hole has no requirements on the hole depth, and the first insulating opening and the second insulating opening are both opened from the side with fewer layers away from the top layer or the bottom layer, so that the hole depth is smaller each time, and the hole depth can be controlled more accurately. At the same time, the upper and lower limits of the conductive openings and the insulating openings in this solution are greatly different, which can reduce the accuracy requirements on the hole depth, thereby improving the hole opening efficiency, thereby realizing interlayer interconnection of any circuit layer, and improving the freedom of circuit design.

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

[0123] The insulating material is filled by printing or plugging 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 a specific implementation, the conductive material is a metal paste, and in some specific embodiments, the conductive material is a silver paste, a copper paste or a gold paste. The insulating material is a plugging resin or a plugging 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 lamination layer is prepreg or insulating resin.

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

[0130] Example 2

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

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

[0133] In a specific embodiment, Figure 5A As shown, the initial multi-layer circuit board includes the second circuit layer 12, the first board layer 1, the first lamination layer 100, the third circuit layer 13 and the second board layer 2 in sequence.

[0134] S202, connecting the target circuit layers, the target circuit layers include 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 facing 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 facing away from the first target circuit layer; the number of 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 board layers.

[0135] In a specific embodiment, 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 the third circuit layer 13 facing the second circuit layer 12 is 1 (i.e., the first board layer 1), which is equal to 1 / 2 of the total number of board layers 2. Among them, 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, forming a conductive opening from the top layer or bottom layer of the first target circuit layer on the side facing away from the second target circuit layer in the initial multi-layer circuit board through to the second target circuit layer or to the structural layer adjacent to the side of the second target circuit layer facing away from the first target circuit layer.

[0138] In a specific embodiment, Figure 5AAs shown, a hole is opened from the first board layer 1 to the third circuit layer 13 or to the second board layer 2, forming a conductive opening 101A or 101B. The conductive opening 101A is the minimum depth, the conductive opening 101B is the maximum depth, and n=3. The hole depth of the conductive opening is less than the thickness of 5 structural layers (2 board layers + 2 circuit layers + 1 laminate layer) of 1300μm; the hole depth of the conductive opening is greater than the thickness of 3 structural layers (1 board layer + 1 circuit layer + 1 laminate layer) of 750μm.

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

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

[0141] In a specific embodiment, Figure 5B As shown, the conductive opening 101A or 101B is filled with a conductive material to form an initial conductive hole 102A or 102B.

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

[0143] In a specific embodiment, Figure 5C As shown, at the initial conductive hole 102A or 102B, the first board layer 1 is opened to penetrate into the second circuit layer 12 or penetrate into the first board layer 1, forming an insulating opening 201A or 201B. The insulating opening 201A is the maximum depth, the insulating opening 201B is the minimum depth, and a=1. The hole depth of the insulating opening is less than the thickness of 2 structural layers (1 board layer + 1 circuit layer) 550μm; the hole depth of the insulating opening is greater than the thickness of 0 structural layer (0 board layer) 0μm.

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

[0145] S202-4, filling the insulating opening with insulating material to form insulating holes; the remaining initial conductive holes form target conductive holes, and the target conductive holes connect the first target circuit layer and the second target circuit layer.

[0146] In a specific embodiment, Figure 5D As shown, the insulating opening 201A or 201B is filled with an insulating material to form an insulating hole 202A or 202B; the remaining initial conductive holes form target conductive holes, and the target conductive holes connect the first target circuit layer and the second target circuit layer.

[0147] S203, forming a top wiring layer and a bottom wiring layer on one side surface of the top layer and one side surface of the bottom layer of the initial multi-layer wiring board, respectively.

[0148] In a specific embodiment, Figure 5E As shown, a first circuit layer 11 and a fourth circuit layer 14 are respectively formed on one surface of the top layer and one surface of the bottom layer of the initial multi-layer circuit board, wherein 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 Figure 7A to Figure 7F This embodiment provides another specific process of a method for manufacturing a multilayer circuit board, including steps S301-S303:

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

[0152] In a specific embodiment, Fig. 7AAs shown, the initial multi-layer circuit board includes the first board layer 1, the second circuit layer 12, the first pressing layer 100, the third circuit layer 13, the second board layer 2, the fourth circuit layer 14, the second pressing layer 200, the fifth circuit layer 15, and the third board layer 3 in sequence.

[0153] S302, connecting the target circuit layers, the target circuit layers include 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 facing 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 facing away from the first target circuit layer; the number of board 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 board layers.

[0154] In a specific embodiment, Fig. 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 number of board layers on the side of the third circuit layer 13 facing the fifth circuit layer 15 is 2 (respectively the second board layer 2 and the third board layer 3), which is greater than 1 / 2 of the total number of board layers 3. Among them, 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.

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

[0156] S302-1, opening a through hole in the initial multi-layer circuit board.

[0157] In a specific embodiment, Fig. 7A As shown, a through hole 103 is opened in the initial multi-layer wiring board.

[0158] S302-2, filling the through hole with a conductive material to form an initial conductive through hole.

[0159] In a specific embodiment, Figure 7B As shown, the via 103 is filled with a conductive material to form an initial conductive via 104 .

[0160] S302-3, reopen 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 to penetrate into the second target circuit layer or into the structural layer adjacent to the side of the second target circuit layer facing away from the first target circuit layer to form a second insulating opening; the diameter of the second insulating opening is larger than the diameter of the through hole.

[0161] In a specific embodiment, Figure 7CAs shown, a new hole is opened at the position of the initial conductive through hole of the first board layer 1 to penetrate into the third circuit layer 13 or into the first laminated layer 100, forming a second insulating opening 203A or 203B. The second insulating opening 203A is the maximum depth, and the second insulating opening 203B is the minimum depth, m=3. The hole depth of the second insulating opening is less than the thickness of 4 structural layers (1 board layer + 2 circuit layers + 1 laminated layer) 800μm; the hole depth of the second insulating opening is greater than the thickness of 2 structural layers (1 board layer + 1 circuit layer) 550μm.

[0162] Preferably, a new hole is opened at the position of the initial conductive through hole in the first board layer 1 to penetrate to a position less than half the thickness in the third circuit layer 13 or to a position greater than half the thickness in the first laminated layer 100, that is, the hole depth of the second insulating opening is less than 775μm of the thickness of 3.5 structural layers (1 board layer + 1.5 circuit layers + 1 laminated layer); the hole depth of the second insulating opening is greater than 650μm of the thickness of 2.5 structural layers (1 board layer + 1 circuit layer + 0.5 laminated layer).

[0163] S302-4, filling the second insulating opening with insulating material to form a second insulating hole.

[0164] In a specific embodiment, Fig.7D As shown, the second insulating opening 203A or 203B is filled with insulating material to form a second insulating hole 204A or 204B.

[0165] S302-5, reopen 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 to penetrate into the first target circuit layer or into the structural layer adjacent to the side of the first target circuit layer facing away from the second target circuit layer to form a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the through hole.

[0166] In a specific embodiment, Fig. 7E As shown, a new hole is opened at the position of the initial conductive through hole of the third board layer 3 to penetrate into the fifth circuit layer 15 or the third board layer 3, forming a first insulating opening 205A or 205B. The first insulating opening 205A is the maximum depth, the first insulating opening 205B is the minimum depth, and a=1. The hole depth of the first insulating opening is less than the thickness of 2 structural layers (1 board layer + 1 circuit layer) 550μm; the hole depth of the first insulating opening is greater than the thickness of 0 structural layer (0 board layer) 0μm.

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

[0168] S302-6, filling the first insulating opening with insulating material to form a first insulating hole; the remaining initial conductive through holes form a target conductive hole, and the target conductive hole connects the first target circuit layer and the second target circuit layer.

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

[0170] S303, forming a top wiring layer and a bottom wiring layer on one side surface of the top layer and one side surface of the bottom layer of the initial multi-layer wiring board, respectively.

[0171] In a specific embodiment, a first circuit layer and a sixth circuit layer are formed on the top layer side surface and the bottom layer side 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 examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for manufacturing a multilayer circuit board, characterized in that: The following steps are involved: Forming an initial multi-layer circuit board; Laminating multiple circuit layers, multiple board layers and at least one laminating layer to form the initial multi-layer circuit board; in the initial multi-layer circuit board: between two adjacent circuit layers is the laminating layer or the board layer; between two adjacent board layers is a laminating layer; between two adjacent laminating layers is a board layer; and the top layer and the bottom layer of the initial multi-layer circuit board are both the board layers; Connecting target circuit layers, wherein the target circuit layers include 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 layer of the lamination layer; comprising the following steps: Opening a conductive opening from the top layer and / or bottom layer of the initial multi-layer circuit board to the opposite side, wherein the conductive opening at least penetrates to the target circuit layer which is farther away from the initial position of the opening; Filling the conductive opening with a conductive material to form an initial conductive hole; At the initial conductive hole, an insulating opening is opened from the top layer and / or bottom layer of the initial multilayer circuit board to the opposite side, and the insulating opening at most penetrates to the target circuit layer which is shorter than the initial position of the opening; Filling the insulating opening with insulating material to form an insulating hole; A top wiring layer and a bottom wiring layer are respectively formed on one side surface of the top layer and one side surface of the bottom layer of the initial multi-layer wiring board.

2. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: The number of layers of the first target circuit layer facing away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer facing away from the first target circuit layer; When the number of the 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 the board layers, The connecting 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, and include: Opening a hole in the top layer or bottom layer of the first target circuit layer on the side facing away from the second target circuit layer in the initial multi-layer circuit board to form a conductive opening; the conductive opening penetrates the first target circuit layer and penetrates into the second target circuit layer; Filling the conductive opening with a conductive material to form an initial conductive hole; At the initial conductive hole, a new hole is opened from the initial opening position of the initial conductive hole to penetrate into the first target circuit layer to form an insulating opening; the diameter of the insulating opening is larger than the diameter of the conductive opening; The insulating opening is filled with an insulating material to form an insulating hole; the remaining initial conductive holes form a target conductive hole, and the target conductive hole connects the first target circuit layer and the second target circuit layer.

3. The method for manufacturing a multilayer circuit board according to claim 2, characterized in that: The conductive opening is formed by opening a hole in the top layer or bottom layer of the initial multi-layer circuit board on the side of the first target circuit layer facing away from the second target circuit layer; The step of the conductive opening penetrating through the first target circuit layer and penetrating into the second target circuit layer further includes: A conductive opening is formed by opening a top layer or bottom layer on the side of the first target circuit layer in the initial multi-layer circuit board that is opposite to the second target circuit layer and extending through the structural layer adjacent to the side of the second target circuit layer that is opposite to the first target circuit layer; the conductive opening passes through the first target circuit layer and the second target circuit layer.

4. The method for manufacturing a multilayer circuit board according to claim 2, characterized in that: At the initial conductive hole, a new hole is opened from the initial opening position of the initial conductive hole to penetrate into the first target circuit layer to form an insulating opening; The step of making the diameter of the insulating opening larger than that of the conductive opening comprises: At the initial conductive hole, a new hole is opened from the initial opening position of the initial conductive hole to the structural layer adjacent to the first target circuit layer on the side facing away from the second target circuit layer, to form an insulating opening; the diameter of the insulating opening is larger than the diameter of the conductive opening.

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

6. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: The number of layers of the first target circuit layer facing away from the second target circuit layer is less than or equal to the number of layers of the second target circuit layer facing away from the first target circuit layer; When the number of the board 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 the board layers, The connecting 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, and include: Opening a through hole in the initial multilayer circuit board; Filling the through hole with a conductive material to form an initial conductive through hole; A new hole is opened 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 to penetrate into the first target circuit layer to form a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the through hole; Filling the first insulating opening with an insulating material to form a first insulating hole; A new hole is opened 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 to penetrate into the second target circuit layer to form a second insulating opening; the diameter of the second insulating opening is larger than the diameter of the through hole; Filling the second insulating opening with an insulating material to form a second insulating hole; The remaining initial conductive vias form a target conductive via that connects the first target wiring layer and the second target wiring layer.

7. The method for manufacturing a multilayer circuit board according to claim 6, characterized in that: Reopening 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 to penetrate into the first target circuit layer to form a first insulating opening; The step of making the diameter of the first insulating opening larger than the diameter of the through hole comprises: A new hole is opened 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 to penetrate into the structural layer adjacent to the side of the first target circuit layer facing away from the second target circuit layer to form a first insulating opening; the diameter of the first insulating opening is larger than the diameter of the through hole.

8. The method for manufacturing a multilayer circuit board according to claim 6, characterized in that: The step of 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 to penetrate into the second target circuit layer to form a second insulating opening; wherein the diameter of the second insulating opening is larger than the diameter of the through hole, comprises: A new hole is opened 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 to penetrate into the structural layer adjacent to the side of the second target circuit layer facing away from the first target circuit layer to form a second insulating opening; the diameter of the second insulating opening is larger than the diameter of the through hole.

9. The method for manufacturing a multilayer circuit board according to claim 6, characterized in that: The number of layers between the first target circuit layer and the top layer or the bottom layer on the side facing away from the second target circuit layer is a layers; The number of layers between the second target circuit layer and the top layer or the bottom layer on the side facing away from the first target circuit layer is m; The maximum depth of the first insulating opening is greater than the thickness of the a+1 structural layer, and the minimum depth is greater than the thickness of the a-1 structural 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.

10. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: The conductive material is filled by electroplating or curing after printing; The insulating material is filled by printing or plugging 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.

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

12. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: The multi-layer circuit board is a planar multi-layer circuit board or a curved multi-layer circuit board.

Images