Circuit board and preparation method thereof, display module and display device

Abstract

The invention discloses a circuit board, a preparation method of the circuit board, a display module and a display device. The conductive part is positioned in the insulating substrate; the insulating dielectric layers are located on at least one side of the insulating substrate in the thickness direction of the insulating substrate, and the thickness of at least one insulating dielectric layer is smaller than that of the insulating substrate; the conductive connector is positioned in the insulating dielectric layer; wherein the conductive piece is connected with the conductive connector. And the light weight of the circuit board is realized.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a circuit board and a preparation method thereof, a display module and a display device. Background Art

[0002] Circuit boards include flexible circuit boards or printed circuit boards. Printed circuit boards (PCBs) enable various electronic components to achieve electrical connections of predetermined circuits. Flexible circuit boards (FPCs) are highly reliable and highly flexible circuit boards made of polyimide or polyester film as substrates. Flexible circuit boards and printed circuit boards are often used to electrically connect to display panels and form display modules.

[0003] As printed circuit boards gradually develop towards being lighter, thinner, shorter and smaller, they have gradually developed from single-layer, double-layer and multi-layer in the early stage to high-density interconnection, substrate-like, package substrate and other high-precision circuit board products. Their main characteristics are that the wiring is becoming more and more dense and the aperture is getting smaller and smaller. Printed circuit boards of related technologies can no longer meet the needs of high-density connections, so high-density interconnection (HDI) structures came into being. High-density interconnection structures have been widely used in various electronic product fields. With the development and demand of the electronic product market, the proportion of high-density interconnection circuit boards is also increasing, and the process requirements are also getting higher and higher. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to achieve the lightweighting of a circuit board, a display module including the circuit board, and a display device in the related art.

[0005] In order to solve the above technical problems, the present invention provides a circuit board, comprising: one or more stacked circuit board units; wherein the circuit board unit comprises: an insulating substrate; a conductive member located in the insulating substrate; an insulating dielectric layer located on at least one side of the insulating substrate along its thickness direction, and the thickness of at least one layer of the insulating dielectric layer is less than the thickness of the insulating substrate; a conductive connector located in the insulating dielectric layer; wherein the conductive member is connected to the conductive connector.

[0006] Optionally, in the circuit board unit, the thickness of any insulating medium layer is 1 / 500 to 1 / 10 of the thickness of the insulating substrate.

[0007] Optionally, in the circuit board unit, the insulating dielectric layer is located on the first side or the second side of the insulating substrate along the thickness direction thereof; or, the insulating dielectric layer is located on the first side and the second side of the insulating substrate along the thickness direction thereof.

[0008] Optionally, the plurality of stacked circuit board units are respectively a first circuit board unit to a Kth circuit board unit, K is an integer greater than or equal to 2; the kth circuit board unit 1 The thickness of at least one insulating dielectric layer in the circuit board unit is less than the kth 2 The thickness of the insulating substrate in the circuit board unit; where k 1 is an integer greater than or equal to 1 and less than or equal to K, k 2 is an integer greater than or equal to 1 and less than or equal to K, and k 2 Not equal to k 1 .

[0009] Optionally, the insulating dielectric layer includes a main dielectric layer and an isolation layer, and the isolation layer is located on both side surfaces of the main dielectric layer along the thickness direction thereof and between the conductive connector and the main dielectric layer.

[0010] Optionally, the hardness of the main medium layer is smaller than the hardness of the isolation layer, and the isolation layer is a water-oxygen isolation layer.

[0011] Optionally, the material of the main dielectric layer includes a photolithography material, and the material of the isolation layer includes silicon nitride.

[0012] Optionally, the thickness of the main dielectric layer is 3 micrometers to 8 micrometers, and the thickness of the isolation layer is 100 nanometers to 500 nanometers.

[0013] Optionally, the insulating medium layer in the circuit board unit is located on one side of the insulating substrate along its thickness direction; the multiple stacked circuit board units include: a stacked first circuit board unit and a second circuit board unit; the insulating substrate in the first circuit board unit is in contact with the insulating substrate in the second circuit board unit; the conductive member in the first circuit board unit is in contact with the conductive member in the second circuit board unit.

[0014] Optionally, the conductive connector includes a connected plug and a wiring layer; for the plug and the wiring layer in the same conductive connector, the plug penetrates the insulating dielectric layer, and the wiring layer is located on the side of the plug away from the insulating substrate and covers a portion of the insulating dielectric layer; wherein the conductive member is connected to the plug of a partial layer.

[0015] Optionally, it further includes: a filling layer penetrating the insulating substrate; wherein the conductive member is located between the filling layer and the insulating substrate.

[0016] Optionally, it further includes: a substrate wiring layer, which is located on both side surfaces of the insulating substrate along its thickness direction; wherein the conductive member is also connected to the substrate wiring layer.

[0017] Optionally, the insulating substrates of multiple stacked circuit board units are arranged at intervals; the circuit board also includes: a first substrate, located between adjacent circuit board units; a first wiring layer, located on both side surfaces of the first substrate along its thickness direction; a first conductive connector, located in the first substrate and connecting the first wiring layers on both sides of the first substrate; wherein the wiring layer of the circuit board unit facing the first substrate is connected to the first wiring layer.

[0018] Optionally, the first substrate and the insulating substrate are both hard insulating substrates, or the first substrate and the insulating substrate are both flexible insulating substrates; or the first substrate is a hard insulating substrate and the insulating substrate is a flexible insulating substrate; or the first substrate is a flexible insulating substrate and the insulating substrate is a hard insulating substrate.

[0019] Optionally, in the same circuit board unit, the insulating dielectric layer is a hard insulating dielectric layer, and the insulating substrate is a hard insulating substrate; or, in the same circuit board unit, the insulating dielectric layer is a flexible insulating dielectric layer, and the insulating substrate is a flexible insulating substrate.

[0020] Optionally, for the insulating substrates in adjacent circuit board units, the insulating substrate in one circuit board unit is a flexible insulating substrate, and the insulating substrate in another circuit board unit is a hard insulating substrate.

[0021] The present application also provides a method for preparing a circuit board, comprising: forming one or more stacked circuit board units; wherein the steps of forming the circuit board units include: forming a conductive member in an insulating substrate; forming an insulating dielectric layer on at least one side of the insulating substrate along its thickness direction, the thickness of at least one layer of the insulating dielectric layer being less than the thickness of the insulating substrate; forming a conductive connector on at least one side of the insulating substrate along its thickness direction; wherein the conductive connector is located in the insulating dielectric layer, and the conductive member is connected to the conductive connector.

[0022] Optionally, the insulating dielectric layer is formed on one side of the insulating substrate along its thickness direction, including: forming a first isolation layer and a main dielectric layer on one side of the insulating substrate along its thickness direction, the main dielectric layer is located on the side of the first isolation layer away from the insulating substrate, and the first isolation layer and the main dielectric layer have a first opening exposing the conductive member; forming a second isolation layer on the side wall of the first opening and on the side of the main dielectric layer away from the first isolation layer, the second isolation layer and the first isolation layer are connected to form an isolation layer; wherein the step of forming the conductive connector on at least one side of the insulating substrate along its thickness direction includes: forming the conductive connector in the first opening.

[0023] Optionally, the step of forming the first isolation layer and the main dielectric layer includes: sequentially forming a stacked first initial isolation layer and an initial main dielectric layer on one side of the insulating substrate along its thickness direction; exposing and developing the initial main dielectric layer to form the main dielectric layer from the initial main dielectric layer; and etching the first initial isolation layer using the main dielectric layer as a mask to form the first initial isolation layer from the first isolation layer.

[0024] Optionally, the step of forming the conductive connector includes: forming a plug on at least one side of the insulating substrate along its thickness direction; forming a wiring layer on the side of the plug away from the insulating substrate, the wiring layer being connected to the plug; the step of forming an insulating dielectric layer on at least one side of the insulating substrate along its thickness direction includes: forming an insulating dielectric layer on at least one side of the insulating substrate along its thickness direction, the insulating dielectric layer covering the side wall of the plug and exposing the surface of the plug on the side away from the insulating substrate; wherein the wiring layer also covers a portion of the insulating dielectric layer.

[0025] The present invention further provides a display module, comprising: a display panel; and the circuit board of the present invention, wherein the circuit board and the display panel are electrically connected.

[0026] The present invention further provides a display device, comprising the display module of the present invention.

[0027] The technical solution of the present invention has the following technical effects:

[0028] In the circuit board provided by the technical solution of the present invention, the thickness of at least one layer of the insulating dielectric layer is less than the thickness of the insulating substrate. Since a conductive connector is provided in the insulating dielectric layer with a smaller thickness, the thickness of the insulating dielectric layer corresponding to the conductive connector is reduced, thereby achieving lightweighting of the circuit board. In particular, when the thicknesses of more insulating dielectric layers are respectively less than the thickness of the insulating substrate, this is more conducive to achieving lightweighting of the circuit board with a high-density conductive connector.

[0029] The method for preparing a circuit board provided by the technical solution of the present invention realizes lightweighting of the circuit board based on the same reason.

[0030] The display module provided by the technical solution of the present invention is lightweight because the circuit board is lightweight, so the display module is lightweight.

[0031] The display device provided by the technical solution of the present invention is lightweight because the display module is lightweight. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 A schematic diagram of the structure of a circuit board provided by an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the structure of a circuit board provided in another embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the structure of a circuit board provided in another embodiment of the present invention;

[0036] Figure 4 A schematic diagram of the structure of a circuit board provided in another embodiment of the present invention;

[0037] Figure 5 A flowchart of a circuit board preparation process provided by another embodiment of the present invention;

[0038] Figures 6 to 12 A structural schematic diagram of a process for preparing a circuit board provided by another embodiment of the present invention;

[0039] Figures 13 to 20 A schematic structural diagram of a process for preparing a circuit board provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] An embodiment of the present invention provides a circuit board, referring to Figure 1 and Figure 2 , including: one or more stacked circuit board units A; wherein the circuit board unit A includes: an insulating substrate 100; a conductive member 110, located in the insulating substrate 100; an insulating dielectric layer 200, located on at least one side of the insulating substrate 100 along its thickness direction, and the thickness of at least one layer of the insulating dielectric layer 200 is less than the thickness of the insulating substrate 100; a conductive connector 203, located in the insulating dielectric layer 200; wherein the conductive member 110 is connected to the conductive connector 203.

[0045] In this embodiment, the thickness of at least one layer of the insulating dielectric layer 200 is less than the thickness of the insulating substrate 100. Since the conductive connector 203 is provided in the insulating dielectric layer 200 with a smaller thickness, the thickness of the insulating dielectric layer 200 corresponding to the conductive connector 203 is reduced, thereby achieving lightweight circuit board. Especially when the thickness of more layers of insulating dielectric layers 200 is respectively less than the thickness of the insulating substrate, it is more conducive to achieving lightweight circuit board with high-density conductive connectors 203.

[0046] In one embodiment, in the circuit board unit A, the thickness of at least one insulating dielectric layer 200 is 1 / 500 to 1 / 10, such as 1 / 500, 1 / 400, 1 / 300, 1 / 200, 1 / 100, 1 / 50 or 1 / 10 of the thickness of the insulating substrate 100. The difference between the thickness of at least one insulating dielectric layer 200 and the thickness of the insulating substrate 100 is large, so it is more conducive to achieving lightweight circuit boards with high-density conductive connectors 203.

[0047] In one embodiment, in the circuit board unit A, the thickness of all insulating dielectric layers 200 is respectively less than the thickness of the insulating substrate 100. In another embodiment, the thickness of some insulating dielectric layers 200 is respectively less than the thickness of the insulating substrate 100.

[0048] It should be noted that one layer of insulating dielectric layer 200 corresponds to one layer of conductive connector 203 .

[0049] In one embodiment, in the circuit board unit A, the insulating dielectric layer 200 is located on the first side or the second side of the insulating substrate 100 along the thickness direction thereof; or, in the circuit board unit A, the insulating dielectric layer 200 is located on the first side and the second side of the insulating substrate 100 along the thickness direction thereof. When in the circuit board unit, the insulating dielectric layer is located on the first side and the second side of the insulating substrate along the thickness direction thereof, the thickness of the insulating dielectric layer 200 corresponding to at least one layer of the conductive connector 203 on both sides of the insulating substrate 100 is reduced, which further facilitates the lightweighting of the circuit board with high-density conductive connectors 203.

[0050] In one embodiment, reference Figure 2 The plurality of stacked circuit board units A include: a stacked first circuit board unit A1 and a stacked second circuit board unit A2. It should be noted that, in other embodiments, the stacked number of circuit board units A may be greater than or equal to three.

[0051] refer to Figure 1 In the circuit board unit A, the insulating dielectric layer 200 is located on the first side of the insulating substrate 100 along the thickness direction as an example. In other embodiments, in the circuit board unit, the insulating dielectric layer is located on the second side of the insulating substrate along the thickness direction. In other embodiments, in the circuit board unit, the insulating dielectric layer is located on the first side and the second side of the insulating substrate along the thickness direction. Figure 2 In a part of the circuit board unit A, for example, in the first circuit board unit A1, the insulating dielectric layer 200 is located on the first side of the insulating substrate 100 along its thickness direction, and in another part of the circuit board unit A, for example, in the second circuit board unit A2, the insulating dielectric layer 200 is located on the second side of the insulating substrate 100 along its thickness direction.

[0052] refer to Figure 1In the circuit board unit A, the insulating substrate 100 has a plurality of stacked insulating dielectric layers 200 along the first side of the thickness direction thereof, and the conductive connectors 203 in the insulating dielectric layers 200 in adjacent layers on the first side of the insulating substrate 100 are connected. In other embodiments, in the circuit board unit, the insulating substrate has a plurality of stacked insulating dielectric layers along the second side of the thickness direction thereof, and the conductive connectors in the insulating dielectric layers in adjacent layers on the second side of the insulating substrate are connected. In other embodiments, in the circuit board unit, the insulating substrate has a plurality of stacked insulating dielectric layers along the first side and the second side of the thickness direction thereof, and the conductive connectors in the insulating dielectric layers in adjacent layers on the first side of the insulating substrate are connected, and the conductive connectors in the insulating dielectric layers in adjacent layers on the second side of the insulating substrate are connected. When the insulating substrate has a plurality of stacked insulating dielectric layers along the first side and the second side of the thickness direction thereof in the circuit board unit, the thickness of at least one insulating dielectric layer on the first side of the insulating substrate along the thickness direction thereof can be selected to be smaller than the thickness of the insulating substrate, and the thickness of at least one insulating dielectric layer on the second side of the insulating substrate along the thickness direction thereof can be selected to be smaller than the thickness of the insulating substrate, so that the lightweight degree of the circuit board unit is improved.

[0053] Figure 2 In one part of the circuit board unit A, for example, in the first circuit board unit A1, the insulating substrate 100 has a plurality of stacked insulating dielectric layers 200 along the first side in the thickness direction thereof, and the conductive connectors 203 in the insulating dielectric layers 200 in adjacent layers on the first side of the insulating substrate 100 are connected; in another part of the circuit board unit A, for example, in the second circuit board unit A2, the insulating substrate 100 has a plurality of stacked insulating dielectric layers 200 along the second side in the thickness direction thereof, and the conductive connectors 203 in the insulating dielectric layers 200 in adjacent layers on the second side of the insulating substrate 100 are connected.

[0054] In one embodiment, the plurality of stacked circuit board units are respectively the first circuit board unit to the Kth circuit board unit, where K is an integer greater than or equal to 2; 1 The thickness of at least one insulating dielectric layer in the circuit board unit is less than the kth 2 The thickness of the insulating substrate in the circuit board unit; where k 1 is an integer greater than or equal to 1 and less than or equal to K, k 2 is an integer greater than or equal to 1 and less than or equal to K, and k 2 Not equal to k 1 .

[0055] In one embodiment, reference Figure 2, the insulating medium layer 200 in the circuit board unit A is located on one side of the insulating substrate 100 along the thickness direction thereof; the multiple stacked circuit board units A include: a stacked first circuit board unit A1 and a second circuit board unit A2; the insulating substrate 100 in the first circuit board unit A1 and the insulating substrate 100 in the second circuit board unit A2 are in contact; the conductive member 110 in the first circuit board unit A1 and the conductive member 110 in the second circuit board unit A2 are in contact. By contacting the insulating substrate 100 in the first circuit board unit A1 and the insulating substrate 100 in the second circuit board unit A2, the conductive member 110 in the first circuit board unit A1 and the conductive member 110 in the second circuit board unit A2 are in contact, so as to realize the pressing of the first circuit board unit A1 and the second circuit board unit A2. And no other intermediate adhesive layer is required between the insulating substrate 100 in the first circuit board unit A1 and the insulating substrate 100 in the second circuit board unit A2, so as to reduce the thickness of the first circuit board unit A1 and the second circuit board unit A2 pressed together.

[0056] It should be noted that Figure 1 and Figure 2 is a cross-sectional view, and the location where a portion of the conductive member 110 and the conductive connector 203 are connected is not Figure 1 and Figure 2 In the cross section, in the stacked adjacent insulating dielectric layers 200, the position where a portion of the conductive connector 203 in one insulating dielectric layer 200 is connected to a portion of the conductive connector 203 in another insulating dielectric layer 200 is not Figure 1 and Figure 2 In the section where it is located.

[0057] In one embodiment, reference Figure 1 and Figure 2 The insulating dielectric layer 200 includes a main dielectric layer 201 and an isolation layer 202. The isolation layer 202 is located on both sides of the main dielectric layer 201 along its thickness direction and between the conductive connector 203 and the main dielectric layer 201. The material of the isolation layer 202 is different from that of the main dielectric layer 201.

[0058] In one embodiment, the hardness of the main dielectric layer 201 is less than the hardness of the isolation layer 202, and the isolation layer 202 is a water-oxygen isolation layer. The isolation layer 202 can isolate water and oxygen, prevent the conductive connector 203 from contacting the main dielectric layer 201, and prevent the conductive connector 203 from being oxidized. The main dielectric layer 201 has a relatively low hardness, which is conducive to realizing a flexible circuit board.

[0059] The main dielectric layer 201 occupies most of the volume of the insulating dielectric layer 200 , and the thickness of the main dielectric layer 201 is much greater than the thickness of the isolation layer 202 .

[0060] In one embodiment, the material of the main dielectric layer 201 includes a photolithographic material, such as polyimide. When the material of the main dielectric layer 201 is a photolithographic material, the sidewall morphology of the first opening for accommodating the conductive connector 203 in the main dielectric layer 201 is better, which is conducive to improving the filling performance of the conductive connector 203. When the material of the main dielectric layer 201 is a photolithographic material, it is not necessary to use a mechanical drilling process and a laser drilling process to form the first opening. Exposure and development can be used to form the first opening of the conductive connector 203, so that the size of the first opening is reduced. The isolation layer 202 occupies a part of the space of the first opening, so the isolation layer 202 can limit the space actually used for the conductive connector 203 in the first opening, so that the width of the conductive connector 203 is reduced.

[0061] In one embodiment, the width of the conductive connection 203 is less than or equal to 5 micrometers, such as 5 micrometers, 3 micrometers, 1 micrometer, or 0.1 micrometer.

[0062] In one embodiment, the material of the isolation layer 202 includes silicon nitride.

[0063] In one embodiment, the thickness of the main dielectric layer 201 is 3 micrometers to 8 micrometers, such as 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers or 8 micrometers. The thickness of the isolation layer 202 is 100 nanometers to 500 nanometers, such as 100 nanometers, 200 nanometers, 300 nanometers, 400 nanometers or 500 nanometers.

[0064] In one embodiment, in the same circuit board unit A, the insulating dielectric layer 200 is a hard insulating dielectric layer, and the insulating substrate 100 is a hard insulating substrate; or, in the same circuit board unit A, the insulating dielectric layer 200 is a flexible insulating dielectric layer, and the insulating substrate 100 is a flexible insulating substrate. Figure 2 In the example, the insulating substrate 100 in the first circuit board unit A1 and the insulating substrate 100 in the second circuit board unit A2 are both hard insulating substrates or both flexible insulating substrates.

[0065] In another embodiment, for the insulating substrates in adjacent circuit board units, the insulating substrate in one circuit board unit is a flexible insulating substrate, and the insulating substrate in the other circuit board unit is a hard insulating substrate.

[0066] When the insulating substrate 100 is a hard insulating substrate, the insulating substrate 100 is a resin substrate or a glass cloth substrate. When the insulating substrate 100 is a flexible insulating substrate, the insulating substrate 100 is a polyimide substrate.

[0067] The material of the conductive member 110 includes copper. The material of the conductive connecting body 203 includes copper.

[0068] When the insulating substrates of the multiple circuit board units of the circuit board are all hard insulating substrates, the circuit board is a hard circuit board. When the insulating substrates of the multiple circuit board units of the circuit board are all flexible insulating substrates, the circuit board is a flexible circuit board. When the insulating substrates of the multiple circuit board units of the circuit board are selected to be partly flexible insulating substrates and the other partly hard insulating substrates, the stress distribution inside the circuit board can be adjusted, and circuit boards of different hardness can be obtained.

[0069] In this embodiment, the circuit board unit A further includes: a wiring layer 300 located on at least one side of the insulating substrate 100 along the thickness direction thereof. Figure 1 In the figure, it is taken as an example that the wiring layer 300 is located on the first side of the insulating substrate 100 along the thickness direction thereof. Figure 2 In the embodiment, the wiring layer 300 in the first circuit board unit A1 is located on a first side of the insulating substrate 100 along its thickness direction, and the wiring layer 300 in the second circuit board unit A2 is located on a second side of the insulating substrate 100 along its thickness direction.

[0070] In the circuit board unit, the wiring layer 300 on the first side of the insulating substrate 100 is located on the side of the multilayer conductive connection body 203 on the first side of the insulating substrate 100 away from the insulating substrate 100 and is connected to the conductive connection body 203. In the circuit board unit, the wiring layer 300 on the second side of the insulating substrate 100 is located on the side of the multilayer conductive connection body 203 on the second side of the insulating substrate 100 away from the insulating substrate 100 and is connected to the conductive connection body 203. The material of the wiring layer 300 includes copper.

[0071] Another embodiment of the present application provides a circuit board, referring to Figure 3 and Figure 4 , comprising: one or more stacked circuit board units A; wherein the circuit board unit A comprises: an insulating substrate 100; a conductive member 110, located in the insulating substrate 100; an insulating dielectric layer 200, located on at least one side of the insulating substrate 100 along its thickness direction, and the thickness of at least one layer of the insulating dielectric layer 200 is less than the thickness of the insulating substrate 100; a conductive connector 203, located in the insulating dielectric layer 200; wherein the conductive member 110 is connected to the conductive connector 203.

[0072] Figure 3 The middle circuit board includes a circuit board unit A. Figure 4 The middle circuit board includes a plurality of stacked circuit board units A, and the plurality of circuit board units A are a first circuit board unit A1 and a second circuit board unit A2.

[0073] In this embodiment, the conductive connector 203 includes a connected plug 203a and a wiring layer 203b; for the plug 203a and the wiring layer 203b in the same conductive connector 203, the plug 203a penetrates the insulating dielectric layer 200, and the wiring layer 203b is located on the side of the plug 203a away from the insulating substrate 100 and covers a portion of the insulating dielectric layer 200; wherein the conductive member 110 is connected to a portion of the layer of the plug 203a.

[0074] The material of the conductive member 110 includes copper. The material of the conductive connecting body 203 includes copper.

[0075] In one embodiment, reference Figure 3 and Figure 4 The circuit board further comprises: a filling layer 112 penetrating the insulating substrate 100; wherein the conductive member 110 is located between the filling layer 112 and the insulating substrate 100. The filling layer 112 may be made of an insulating material or a conductive material. The filling layer 112 may be made of a resin or copper. In one embodiment, Figure 3 and Figure 4 The circuit board further includes: a substrate wiring layer 120 , which is located on both side surfaces of the insulating substrate 100 along its thickness direction; wherein the conductive member 110 is also connected to the substrate wiring layer 120 . Figure 3 and Figure 4 In the embodiment, the conductive member 110 is connected to the substrate wiring layer 120 on both sides of the insulating substrate 100 along the thickness direction thereof. The material of the substrate wiring layer 120 includes copper.

[0076] In one embodiment, in the circuit board unit A, the thickness of at least one insulating medium layer 200 is 1 / 500 to 1 / 10 of the thickness of the insulating substrate 100, for example, 1 / 500, 1 / 400, 1 / 300, 1 / 200, 1 / 100, 1 / 50 or 1 / 10.

[0077] In one embodiment, the plurality of stacked circuit board units are respectively the first circuit board unit to the Kth circuit board unit, where K is an integer greater than or equal to 2; 1 The thickness of at least one insulating dielectric layer in the circuit board unit is less than the kth 2 The thickness of the insulating substrate in the circuit board unit; where k 1 is an integer greater than or equal to 1 and less than or equal to K, k 2 is an integer greater than or equal to 1 and less than or equal to K, and k 2 Not equal to k 1 .

[0078] In one embodiment, in the circuit board unit, the insulating dielectric layer 200 is located on the first side and the second side of the insulating substrate 100 along its thickness direction. In other embodiments, in the circuit board unit, the insulating dielectric layer is located on the first side or the second side of the insulating substrate along its thickness direction.

[0079] In one embodiment, in a circuit board unit, the first side of the insulating substrate has a plurality of stacked insulating dielectric layers, and the conductive connectors in the insulating dielectric layers of adjacent layers on the first side of the insulating substrate are connected; and / or, in a circuit board unit, the second side of the insulating substrate has a plurality of stacked insulating dielectric layers, and the conductive connectors in the insulating dielectric layers of adjacent layers on the second side of the insulating substrate are connected.

[0080] Figure 3 In the circuit board unit A, the first side of the insulating substrate 100 has a multi-layered insulating dielectric layer 200, and the conductive connectors 203 in the insulating dielectric layers 200 of adjacent layers on the first side of the insulating substrate 100 are connected. Figure 4 In the first circuit board unit A1, the first side of the insulating substrate 100 has a plurality of stacked insulating dielectric layers 200, and the conductive connectors 203 in the insulating dielectric layers 200 in adjacent layers on the first side of the insulating substrate 100 are connected; in the second circuit board unit A2, the second side of the insulating substrate 100 has a plurality of stacked insulating dielectric layers 200, and the conductive connectors 203 in the insulating dielectric layers 200 in adjacent layers on the second side of the insulating substrate 100 are connected.

[0081] refer to Figure 4 The circuit board also includes: a first substrate 400, located between adjacent circuit board units A; a first wiring layer 401, located on both side surfaces of the first substrate 400 along its thickness direction; a first conductive connector 402, located in the first substrate 400 and connecting the first wiring layer 401 on both sides of the first substrate 400; wherein the wiring layer 203b of the circuit board unit A facing the first substrate 400 is connected to the first wiring layer 401.

[0082] In one embodiment, the first substrate 400 and the insulating substrate 100 are both hard insulating substrates, or the first substrate 400 and the insulating substrate 100 are both flexible insulating substrates; or the first substrate 400 is a hard insulating substrate and the insulating substrate 100 is a flexible insulating substrate; or the first substrate 400 is a flexible insulating substrate and the insulating substrate 100 is a hard insulating substrate.

[0083] In one embodiment, the thickness of at least one layer of the insulating dielectric layer 200 is less than the thickness of the first substrate 400. Specifically, the thickness of all layers of the insulating dielectric layer 200 is less than the thickness of the first substrate 400, or the thickness of some layers of the insulating dielectric layer 200 is less than the thickness of the first substrate 400.

[0084] In one embodiment, in the same circuit board unit, the insulating dielectric layer 200 is a hard insulating dielectric layer, and the insulating substrate 100 is a hard insulating substrate; or, in the same circuit board unit, the insulating dielectric layer 200 is a flexible insulating dielectric layer, and the insulating substrate 100 is a flexible insulating substrate.

[0085] In one embodiment, for the insulating substrates 100 in the adjacent circuit board units, the insulating substrate 100 in one circuit board unit is a flexible insulating substrate, and the insulating substrate 100 in the other circuit board unit is a hard insulating substrate.

[0086] Another embodiment of the present application provides a method for preparing a circuit board, referring to Figure 5 , comprising: forming one or more stacked circuit board units; wherein the step of forming the circuit board unit comprises:

[0087] Step S1: forming a conductive member in an insulating substrate;

[0088] Step S2: forming an insulating dielectric layer on at least one side of the insulating substrate along its thickness direction, wherein the thickness of at least one insulating dielectric layer is less than the thickness of the insulating substrate;

[0089] Step S3: forming a conductive connector on at least one side of the insulating substrate along its thickness direction; wherein the conductive connector is located in the insulating medium layer, and the conductive member is connected to the conductive connector.

[0090] Combine the following Figures 6 to 12 The details are explained below.

[0091] refer to Figure 6 , a conductive member 110 is formed in an insulating substrate 100 .

[0092] In one embodiment, the step of forming the conductive member 110 in the insulating substrate 100 includes: forming a first groove penetrating the insulating substrate 100 in the insulating substrate 100; forming the conductive member 110 in the first groove. The process of forming the first groove includes a mechanical processing process or a laser processing process. The process of forming the conductive member 110 in the first groove includes a deposition process or an electroplating process.

[0093] refer to Figure 7 and Figure 8, forming the insulating dielectric layer 200 on one side of the insulating substrate 100 along the thickness direction thereof, comprising: referring to Figure 7 A first isolation layer 202a and a main dielectric layer 201 are formed on one side of the insulating substrate 100 along its thickness direction, and the main dielectric layer 201 is located on the side of the first isolation layer 202a away from the insulating substrate 100, and the first isolation layer 202a and the main dielectric layer 201 have a first opening 204 exposing the conductive member 110.

[0094] In one embodiment, forming a first isolation layer 202a and a main dielectric layer 201 on one side of the insulating substrate 100 along its thickness direction includes: sequentially forming a stacked first initial isolation layer and an initial main dielectric layer on one side of the insulating substrate 100 along its thickness direction; exposing and developing the initial main dielectric layer to form the main dielectric layer 201; and etching the first initial isolation layer using the main dielectric layer 201 as a mask to form the first initial isolation layer 202a.

[0095] Since the initial main dielectric layer is exposed and developed to form the main dielectric layer 201, the width of the first opening 204 in the main dielectric layer 201 formed by the exposure and development is smaller than that by the mechanical drilling process or the laser drilling process. The first initial isolation layer is etched using the main dielectric layer 201 as a mask to form the first isolation layer 202a from the first initial isolation layer. Therefore, the width of the first opening in the first isolation layer 202a is smaller.

[0096] The process of forming the first preliminary isolation layer includes a deposition process.

[0097] The material of the initial main dielectric layer includes a photolithography material. The process of forming the initial main dielectric layer includes a coating process.

[0098] The material and thickness of the main dielectric layer 201 refer to the above-mentioned embodiment.

[0099] refer to Figure 8 , forming the insulating dielectric layer 200 on one side of the insulating substrate 100 along its thickness direction, and also including: forming a second isolation layer 202b on the side wall of the first opening 204 and the side of the main dielectric layer 201 away from the first isolation layer 202a, the second isolation layer 202b and the first isolation layer 202a are connected to form an isolation layer 202.

[0100] The process of forming the second isolation layer 202 b includes a deposition process.

[0101] The material and thickness of the isolation layer 202 refer to the above-mentioned embodiment.

[0102] The second isolation layer 202 b occupies a portion of the space of the first opening 204 , so the second isolation layer 202 b can limit the space actually used for the conductive connection in the first opening 204 , thereby reducing the width of the conductive connection.

[0103] refer to Fig. 9 , forming the conductive connector 203 on at least one side of the insulating substrate 100 along its thickness direction, including: forming the conductive connector 203 in the first opening 204.

[0104] The process of forming the conductive connection body 203 in the first opening 204 includes an electroplating process.

[0105] The material description of the conductive connecting body 203 refers to the aforementioned embodiment.

[0106] refer to Fig.10 , repeat step S2 and step S3 to form a multi-layer insulating dielectric layer 200 and a multi-layer conductive connector 203.

[0107] refer to Fig.11 A wiring layer 300 is formed on the side of the multi-layer insulating dielectric layer 200 away from the insulating substrate 100 , and the wiring layer 300 is connected to the conductive connector 203 .

[0108] refer to Fig.12 , the first circuit board unit A1 and the second circuit board unit A2 are pressed together.

[0109] In one embodiment, the insulating substrate 100 in the first circuit board unit A1 contacts the insulating substrate 100 in the second circuit board unit A2; the conductive member 110 in the first circuit board unit A1 contacts the conductive member 110 in the second circuit board unit A2.

[0110] It should be noted that in a circuit board in the related art, the steps of forming a through-hole structure in the circuit board include: forming a through-hole; forming a through-hole structure in the through-hole. The process of forming the through-hole is a mechanical drilling process or a laser drilling process. The process of forming the through-hole structure in the through-hole adopts an electroplating process. However, the aperture of the through-hole formed by the mechanical drilling process is about 75 microns to 100 microns. Although the processing capability of the laser drilling process for the aperture of the through-hole is much higher than that of the mechanical drilling process for the aperture of the through-hole, the hole wall quality of the through-hole formed by the laser drilling process is affected by many factors and becomes very unstable.

[0111] However, in this embodiment, the size of the first opening is small and the sidewall quality of the first opening is good, so the filling performance and filling quality of the conductive connection body 203 formed in the first opening are improved.

[0112] Another embodiment of the present application provides a method for preparing a circuit board, referring to Figure 5 , comprising: forming one or more stacked circuit board units; wherein the step of forming the circuit board unit comprises:

[0113] Step S1: forming a conductive member in an insulating substrate;

[0114] Step S2: forming an insulating dielectric layer on at least one side of the insulating substrate along its thickness direction, wherein the thickness of at least one insulating dielectric layer is less than the thickness of the insulating substrate;

[0115] Step S3: forming a conductive connector on at least one side of the insulating substrate along its thickness direction; wherein the conductive connector is located in the insulating medium layer, and the conductive member is connected to the conductive connector.

[0116] The step of forming the conductive connector includes: forming a plug on at least one side of the insulating substrate along the thickness direction; forming a wiring layer on the side of the plug away from the insulating substrate, the wiring layer being connected to the plug. The step of forming an insulating dielectric layer on at least one side of the insulating substrate along the thickness direction includes: forming an insulating dielectric layer on at least one side of the insulating substrate along the thickness direction, covering the side wall of the plug and exposing the surface of the plug away from the insulating substrate; wherein the wiring layer also covers part of the insulating dielectric layer.

[0117] Combine the following Figures 13 to 20 The details are explained below.

[0118] refer to Fig.13 , providing an insulating substrate 100.

[0119] The description of the material and thickness of the insulating substrate 100 refers to the aforementioned embodiment and will not be described in detail.

[0120] refer to Fig.14 , a first groove 1001 is formed in the insulating substrate 100 .

[0121] The first groove 1001 penetrates the insulating substrate 100 .

[0122] The process of forming the first groove 1001 includes a mechanical processing process or a laser processing process.

[0123] refer to Fig.15 , a conductive member 110 is formed in the first groove 1001 .

[0124] The process of forming the conductive member 110 in the first groove 1001 includes a deposition process or an electroplating process.

[0125] In this embodiment, the method further includes: forming a substrate wiring layer 120 on both side surfaces of the insulating substrate 100 along the thickness direction thereof, wherein the conductive member 110 is further connected to the substrate wiring layer 120 .

[0126] In one embodiment, the substrate wiring layer 120 is formed during the process of forming the conductive member 110 , which simplifies the process.

[0127] In one embodiment, the steps of forming the conductive member 110 and the substrate wiring layer 120 include: forming a conductive material layer on the sidewall of the first groove 1001 and on both side surfaces of the insulating substrate 100 along the thickness direction thereof; patterning the conductive material layer on both side surfaces of the insulating substrate 100 along the thickness direction thereof to form the substrate wiring layer 120, wherein the conductive material layer on the sidewall of the first groove 1001 forms the conductive member 110. The process of forming the conductive material layer includes a deposition process.

[0128] In this embodiment, it also includes: forming a filling layer 112 in the first groove 1001. Specifically, the filling layer 112 is formed in the first groove 1001 after the conductive material layer is formed and before the conductive material layer on both side surfaces of the insulating substrate 100 along its thickness direction is patterned.

[0129] The filling layer 112 penetrates through the filling layer 112 of the insulating substrate 100 ; wherein the conductive member 110 is located between the filling layer 112 and the insulating substrate 100 .

[0130] The material of the filling layer 112 is as described in the above embodiment.

[0131] refer to Fig.16 The step of forming the conductive connection body 203 includes: forming a plug 203a on at least one side of the insulating substrate 100 along the thickness direction thereof. Fig.16 In the example, the plugs 203a are formed on both sides of the insulating substrate 100 in the thickness direction thereof.

[0132] The process of forming the plug 203 a includes an electroplating process.

[0133] The substrate wiring layer 120 is connected to the plug 203 a .

[0134] refer to Fig.17 An insulating dielectric layer 200 is formed on at least one side of the insulating substrate 100 along the thickness direction thereof, covering the side wall of the plug 203 a and exposing a surface of the plug 203 a facing away from the insulating substrate 100 .

[0135] In one embodiment, the step of forming the insulating dielectric layer 200 includes: forming an initial insulating dielectric layer covering the plug 203a on at least one side of the insulating substrate 100 along the thickness direction thereof, the initial insulating dielectric layer covering the sidewall of the plug 203a and the surface of the plug 203a facing away from the insulating substrate 100; grinding the initial insulating dielectric layer until the surface of the plug 203a facing away from the insulating substrate 100 is exposed, thereby forming the insulating dielectric layer 200. The process of forming the initial insulating dielectric layer includes a lamination process or a deposition process.

[0136] refer to Fig.18 The step of forming the conductive connector 203 further includes: forming a wiring layer 203b on a side of the plug 203a away from the insulating substrate 100, wherein the wiring layer 203b is connected to the plug 203a.

[0137] In this embodiment, the formation of the conductive connector 203 does not require a mechanical drilling process or a laser drilling process, nor does it require a hole filling process. After forming the plug 203a, an insulating dielectric layer 200 covering the plug 203a is formed. Therefore, the formation of the plug 203a is not restricted by the insulating dielectric layer 200, so that the morphology and quality of the plug 203a are improved. After forming the insulating dielectric layer 200, a wiring layer 203b is formed. The formation of the wiring layer 203b is not restricted by the insulating dielectric layer 200, so that the morphology and quality of the wiring layer 203b are improved.

[0138] refer to Fig.19 , repeat step S2 and step S3 to form a multi-layer insulating dielectric layer 200 and a multi-layer conductive connector 203.

[0139] refer to Fig. 20 , the first circuit board unit A1 and the second circuit board unit A2 are pressed together.

[0140] In this embodiment, a first substrate 400 is provided, and the first substrate 400 has a first wiring layer 401 on both side surfaces along the thickness direction thereof; the first substrate 400 has a first conductive connector 402, and the first conductive connector 402 connects the first wiring layer 401 on both sides of the first substrate 400; the first substrate 400 is arranged between adjacent circuit board units A, for example, the first substrate 400 is arranged between the first circuit board unit A1 and the second circuit board unit A2; the step of pressing the first circuit board unit A1 and the second circuit board unit A2 together includes: connecting the wiring layer 203b of the circuit board unit A facing the first substrate 400 with the first wiring layer 401, for example, connecting the wiring layer 203b of the first circuit board unit A1 facing the first substrate 400 with the first wiring layer 401, and connecting the wiring layer 203b of the second circuit board unit A2 facing the first substrate 400 with the first wiring layer 401.

[0141] The description of the first substrate and the insulating substrate refers to the aforementioned embodiment and will not be described in detail.

[0142] Another embodiment of the present invention further provides a display module, comprising: a display panel; and the circuit board of the above embodiment; the circuit board and the display panel are electrically connected.

[0143] Another embodiment of the present invention provides a display device, including the display module of the above embodiment.

[0144] Since the principle of solving the problem of the display device is similar to that of the aforementioned display module, the implementation of the display module in the display device can refer to the implementation of the aforementioned display module, and the repeated parts will not be repeated. The display device can be: a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, or any other product or component with a display function. The other essential components of the display device should be understood by ordinary technicians in the field, and will not be repeated here, nor should they be used as a limitation to the present invention.

[0145] 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 circuit board, characterized in that: include: One or more stacked circuit board units; wherein the circuit board unit comprises: Insulating substrate; A conductive member, located in the insulating substrate; an insulating dielectric layer, located on at least one side of the insulating substrate along the thickness direction thereof, wherein the thickness of at least one insulating dielectric layer is less than the thickness of the insulating substrate; A conductive connector, located in the insulating dielectric layer; Wherein, the conductive member is connected to the conductive connecting body.

2. The circuit board according to claim 1, characterized in that: In the circuit board unit, the thickness of at least one insulating medium layer is 1 / 500 to 1 / 10 of the thickness of the insulating substrate.

3. The circuit board according to claim 1, characterized in that: In the circuit board unit, the insulating medium layer is located on the first side or the second side of the insulating substrate along the thickness direction thereof; or, the insulating medium layer is located on the first side and the second side of the insulating substrate along the thickness direction thereof.

4. The circuit board according to claim 1, characterized in that: The multiple stacked circuit board units are respectively the first circuit board unit to the Kth circuit board unit, K is an integer greater than or equal to 2; the thickness of at least one layer of the insulating medium layer in the k1th circuit board unit is less than the thickness of the insulating substrate in the k2th circuit board unit; wherein k1 is an integer greater than or equal to 1 and less than or equal to K, k2 is an integer greater than or equal to 1 and less than or equal to K, and k2 is not equal to k1.

5. The circuit board according to claim 1, characterized in that: The insulating dielectric layer comprises a main dielectric layer and an isolation layer, wherein the isolation layer is located on both side surfaces of the main dielectric layer along the thickness direction thereof and between the conductive connector and the main dielectric layer.

6. The circuit board according to claim 5, characterized in that: The hardness of the main medium layer is less than that of the isolation layer, and the isolation layer is a water-oxygen isolation layer.

7. The circuit board according to claim 5 or 6, characterized in that: The material of the main dielectric layer includes photolithography material, and the material of the isolation layer includes silicon nitride.

8. The circuit board according to claim 5 or 6, characterized in that: The thickness of the main dielectric layer is 3 micrometers to 8 micrometers, and the thickness of the isolation layer is 100 nanometers to 500 nanometers.

9. The circuit board according to claim 1, characterized in that: The insulating medium layer in the circuit board unit is located on one side of the insulating substrate along the thickness direction thereof; The plurality of stacked circuit board units include: a stacked first circuit board unit and a second circuit board unit; the insulating substrate in the first circuit board unit is in contact with the insulating substrate in the second circuit board unit; The conductive member in the first circuit board unit is in contact with the conductive member in the second circuit board unit.

10. The circuit board according to claim 1, characterized in that: The conductive connector includes a connected plug and a wiring layer; for the plug and the wiring layer in the same conductive connector, the plug penetrates the insulating dielectric layer, and the wiring layer is located on a side of the plug away from the insulating substrate and covers a portion of the insulating dielectric layer; Wherein, the conductive element is connected to the plugs of a part of the layers.

11. The circuit board according to claim 10, characterized in that: Also includes: A filling layer that penetrates the insulating substrate; wherein the conductive member is located between the filling layer and the insulating substrate.

12. The circuit board according to claim 10 or 11, characterized in that: Also includes: The substrate wiring layer is located on both side surfaces of the insulating substrate along the thickness direction thereof; wherein the conductive member is also connected to the substrate wiring layer.

13. The circuit board according to claim 10, characterized in that: The insulating substrates of the plurality of stacked circuit board units are arranged at intervals; The circuit board further comprises: a first substrate, located between adjacent circuit board units; a first wiring layer, located on both side surfaces of the first substrate along the thickness direction thereof; a first conductive connector, located in the first substrate and connecting the first wiring layers on both sides of the first substrate; The wiring layer of the circuit board unit facing the first substrate is connected to the first wiring layer.

14. The circuit board according to claim 13, characterized in that: The first substrate and the insulating substrate are both hard insulating substrates, or the first substrate and the insulating substrate are both flexible insulating substrates; or the first substrate is a hard insulating substrate and the insulating substrate is a flexible insulating substrate; or the first substrate is a flexible insulating substrate and the insulating substrate is a hard insulating substrate.

15. The circuit board according to claim 1 or 13, characterized in that: In the same circuit board unit, the insulating dielectric layer is a hard insulating dielectric layer, and the insulating substrate is a hard insulating substrate; or, in the same circuit board unit, the insulating dielectric layer is a flexible insulating dielectric layer, and the insulating substrate is a flexible insulating substrate.

16. The circuit board according to claim 1, characterized in that: For the insulating substrates in the adjacent circuit board units, the insulating substrate in one circuit board unit is a flexible insulating substrate, and the insulating substrate in the other circuit board unit is a hard insulating substrate.

17. A method for preparing a circuit board, characterized in that: The method comprises: forming one or more stacked circuit board units; wherein the step of forming the circuit board unit comprises: forming a conductive member in an insulating substrate; forming an insulating dielectric layer on at least one side of the insulating substrate along the thickness direction thereof, wherein the thickness of at least one insulating dielectric layer is smaller than the thickness of the insulating substrate; forming a conductive connector on at least one side of the insulating substrate along the thickness direction thereof; Wherein, the conductive connecting body is located in the insulating medium layer, and the conductive member is connected to the conductive connecting body.

18. The method for preparing a circuit board according to claim 17, characterized in that: The insulating dielectric layer is formed on one side of the insulating substrate along the thickness direction thereof, comprising: A first isolation layer and a main dielectric layer are formed on one side of the insulating substrate along the thickness direction thereof, the main dielectric layer is located on the side of the first isolation layer away from the insulating substrate, and the first isolation layer and the main dielectric layer have a first opening exposing the conductive member; a second isolation layer is formed on the sidewall of the first opening and on the side of the main dielectric layer away from the first isolation layer, the second isolation layer is connected to the first isolation layer and constitutes an isolation layer; The step of forming the conductive connector on at least one side of the insulating substrate along the thickness direction thereof includes: forming the conductive connector in the first opening.

19. The method for preparing a circuit board according to claim 18, characterized in that: The steps of forming the first isolation layer and the main dielectric layer include: sequentially forming a stacked first initial isolation layer and an initial main dielectric layer on one side of the insulating substrate along its thickness direction; exposing and developing the initial main dielectric layer so that the initial main dielectric layer forms the main dielectric layer; and etching the first initial isolation layer using the main dielectric layer as a mask so that the first initial isolation layer forms the first isolation layer.

20. The method for preparing a circuit board according to claim 17, characterized in that: The step of forming the conductive connector includes: forming a plug on at least one side of the insulating substrate along the thickness direction thereof; forming a wiring layer on a side of the plug away from the insulating substrate, wherein the wiring layer is connected to the plug; The step of forming an insulating dielectric layer on at least one side of the insulating substrate along its thickness direction includes: forming an insulating dielectric layer on at least one side of the insulating substrate along its thickness direction, covering the side wall of the plug and exposing the surface of the plug facing away from the insulating substrate; wherein the wiring layer also covers a portion of the insulating dielectric layer.

21. A display module, characterized in that: include: Display panel; The circuit board according to any one of claims 1 to 16, wherein the circuit board is electrically connected to the display panel.

22. A display device, characterized in that: Includes the display module described in claim 21.

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