CN112203402A

CN112203402A - Printed circuit board and preparation method thereof

Info

Publication number: CN112203402A
Application number: CN202011165831.6A
Authority: CN
Inventors: 常煜; 朱熠民
Original assignee: Shenzhen Institute of Advanced Technology of CAS
Current assignee: Shenzhen Pinte Circuit Co ltd
Priority date: 2020-10-27
Filing date: 2020-10-27
Publication date: 2021-01-08
Anticipated expiration: 2040-10-27
Also published as: CN112203402B

Abstract

The application relates to the technical field of circuit boards, and provides a printed circuit board and a preparation method thereof. The printed circuit board comprises a rigid printed circuit board and an elastic printed circuit board which are combined in a laminated mode, wherein the elastic printed circuit board comprises an elastic base body and a first conductive circuit layer combined on the surface of one side of the elastic base body; the rigid printed circuit board comprises a rigid substrate and a second conductive circuit layer combined on one side surface of the rigid substrate; the surface of one side of an elastic base body in the elastic printed circuit board is bonded on the surface of one side of a second conductive circuit layer in the rigid printed circuit board through a first polysiloxane layer; the printed circuit board is provided with a metallized hole. Because the printed circuit board that this application provided has good elasticity and reliability concurrently, printed circuit board's application can further expand.

Description

Printed circuit board and preparation method thereof

Technical Field

The invention belongs to the technical field of circuit boards, and particularly relates to a printed circuit board and a preparation method thereof.

Background

Conventional Printed circuit boards (also called Printed circuit boards, PCBs) are generally classified into rigid boards, flexible boards, and rigid-flex boards according to the type of a substrate. The rigid plate is widely used, and various components can be reliably welded on the rigid plate. The flexible board has the characteristics of flexibility, lightness and thinness, but the reliability of components welded on the flexible board is not high in the bending process, and the problem of welding spot failure is easy to occur. Therefore, when soldering components to the flexible board, the components are usually soldered only to the flexible board in a fixed bent state, and the components are not soldered to the flexible board which is required to be bent repeatedly, and the flexible board is usually used only as a lead. A flex-rigid board is a circuit board that combines a rigid board and a flexible board, where the flexible board region provides features of flexibility, thinness, and thinness, while the rigid board region provides features of reliable component soldering, providing a more compact, lighter, and more reliable printed circuit format overall. The rigid region and the flexible region of the rigid-flex printed circuit board are not simply directly attached to each other, but are communicated with each other by means of metallized holes. Compared with other combination modes, such as welding, conductive adhesive and connector modes, the mode is more efficient and reliable, the space is saved, and more precise connection can be realized.

With the development of wearable electronics in recent years, an elastic printed circuit board having a stretchable elastic material as a base material has received much attention. The elastic printed circuit board can be prepared on the basis of the traditional printed circuit board by various methods, such as: printing elastic conductive ink on an elastic substrate, preparing a thin metal layer on a pre-stretched substrate, implementing an elastic circuit using a stretchable structure, and the like. Among them, the conventional printed circuit board is manufactured into a stretchable structure, such as a horseshoe shape, a semicircular shape, etc., which is a mainstream method for manufacturing an elastic printed circuit board at present. There are few reports on the development of multilayer flexible circuit boards, and mainly the process of metallizing the holes of the flexible substrate itself is different from the conventional process. The scholars report a preparation process of a multilayer elastic printed circuit board, firstly, horseshoe-shaped copper conducting wires are prepared from copper-clad polyimide in a laser cutting mode, then, the horseshoe-shaped copper conducting wires are bonded to the surface of a silicon rubber substrate by using a water-soluble adhesive tape, and components are welded on a copper bonding pad to obtain the single-sided elastic printed circuit board. And then laminating a plurality of single-sided elastic printed circuit boards together and bonding the single-sided elastic printed circuit boards by using a water-soluble adhesive tape to form the structure of the multilayer elastic printed circuit board. The preparation process of the metallized through hole between each layer of circuit board comprises the steps of firstly carrying out selective laser ablation on a designed position, removing silicon rubber on the position, reserving a lower layer of copper bonding pad to form a blind hole, filling tin paste into the blind hole in a screen printing mode to form a tin column, and finally bonding the tin paste with an upper layer of copper bonding pad in a heating mode to realize the conduction of two layers of circuit boards. Because the elastic circuit is necessarily stretchable in use, components are directly welded on the elastic circuit in a traditional welding and bonding mode, and the problem of serious reliability exists.

Disclosure of Invention

The application aims to provide a printed circuit board and a preparation method thereof, and aims to solve the problem that the existing elastic circuit board is poor in reliability.

In order to achieve the purpose of the application, the technical scheme adopted by the application is as follows:

in a first aspect, the present application provides a printed circuit board comprising a rigid printed circuit board and an elastic printed circuit board which are combined in a stacked manner, wherein the elastic printed circuit board comprises an elastic base body and a first conductive circuit layer combined on one side surface of the elastic base body; the rigid printed circuit board comprises a rigid substrate and a second conductive circuit layer combined on one side surface of the rigid substrate;

the printed circuit board further comprises a first polysiloxane layer, and one side surface of an elastic base body in the elastic printed circuit board is bonded on one side surface of a second conductive circuit layer in the rigid printed circuit board through the first polysiloxane layer;

the printed circuit board is provided with a metallized hole.

Optionally, the elastic base is made of a silica gel material, and a second polysiloxane layer is arranged between the elastic base and the first conductive circuit layer.

Optionally, the thickness of the first polysiloxane layer is less than or equal to 1 μm.

Optionally, the thickness of the second polysiloxane layer is less than or equal to 1 μm.

Optionally, the thickness of the first polysiloxane layer is less than or equal to 1 μm, and the thickness of the second polysiloxane layer is less than or equal to 1 μm.

Optionally, the first conductive circuit layer includes a first copper circuit layer combined on the elastic base body, and a first nickel circuit layer disposed on a side surface of the first copper circuit layer facing away from the elastic base body.

Optionally, the second conductive circuit layer includes a second copper circuit layer combined on the rigid substrate, and a second nickel circuit layer disposed on a side surface of the second copper circuit layer facing away from the rigid substrate.

Optionally, the first conductive circuit layer includes a first copper circuit layer bonded on the elastic base, and a first nickel circuit layer disposed on a side surface of the first copper circuit layer facing away from the elastic base; the second conductive circuit layer comprises a second copper circuit layer combined on the rigid base body and a second nickel circuit layer arranged on the surface of one side, away from the rigid base body, of the second copper circuit layer.

In a second aspect, the present application provides a method of manufacturing a printed circuit board, the method comprising:

obtaining a rigid printed circuit board and an elastic printed circuit prefabricated board, wherein the elastic printed circuit prefabricated board comprises an elastic base body, a first conductive circuit layer combined on one side surface of the elastic base body, and a copper layer combined on the surface, away from the elastic base body, of the first conductive circuit layer, and the copper layer extends to the surface of the elastic base body between the first conductive circuit layers; the rigid printed circuit board comprises a rigid substrate and a second conductive circuit layer combined on one side surface of the rigid substrate;

adhering one side surface of an elastic base body in the elastic printed circuit prefabricated plate on one side surface of a second conductive circuit layer in the rigid printed circuit board through a polysiloxane material to obtain a prefabricated printed circuit board;

in a preset punching area, punching the prefabricated printed circuit board to form a hole;

preparing a metal layer on the wall surface of the hole to prepare a metallized hole;

and removing the copper layer on the surface of the elastic printed circuit board prefabricated plate to obtain the printed circuit board.

Optionally, preparing a metal layer on the wall surface of the hole to obtain a metalized hole includes:

and preparing a third polysiloxane layer on the wall surface of the hole, and preparing a metal layer on the surface of the third polysiloxane layer to obtain the metallized hole.

Optionally, the elastic printed circuit prefabricated board further comprises a second polysiloxane layer arranged between the elastic base body and the first conductive circuit layer; the preparation method of the elastic printed circuit prefabricated plate comprises the following steps:

obtaining a first conductive circuit layer prefabrication sample, wherein the first conductive circuit layer prefabrication sample comprises a substrate, a copper layer combined on the surface of one side of the substrate and a first conductive circuit layer combined on the surface of one side, away from the substrate, of the copper layer;

preparing a third polysiloxane layer on the side surface of the first conducting circuit layer prefabricated sample;

after the surface treatment is carried out on the third polysiloxane layer, an elastic matrix is prepared on the surface of the third polysiloxane layer;

and peeling the substrate to obtain the elastic printed circuit prefabricated board.

Optionally, the step of adhering one side surface of the elastic base body in the elastic printed circuit board prefabricated board to one side surface of the second conductive circuit layer in the rigid printed circuit board through a polysiloxane material to obtain a prefabricated printed circuit board includes:

depositing the polysiloxane material on the surface of one side of the second conducting circuit layer of the rigid printed circuit board to prepare a first polysiloxane coating;

and adhering one side surface of the elastic base body in the elastic printed circuit prefabricated plate on one side surface of the second conductive circuit layer in the rigid printed circuit board through a first polysiloxane layer to obtain the prefabricated printed circuit board.

depositing the polysiloxane material on the surface of one side of the elastic matrix of the elastic printed circuit prefabricated board to prepare a first polysiloxane coating;

and adhering the surface of one side of the second conductive circuit layer in the rigid printed circuit board to the surface of one side of the elastic base body in the elastic printed circuit prefabricated board through the first polysiloxane layer to obtain the prefabricated printed circuit board.

Optionally, the structural monomer of the polysiloxane material is selected from a siloxane compound containing at least one of amino, mercapto, epoxy, hydroxyl, carboxyl and alkyl or a siloxane compound prepolymer.

The application provides a printed circuit board at first, combines rigidity printed circuit board and elasticity printed circuit board to form same printed circuit board to make printed circuit board can weld components and parts on rigidity printed circuit board, elasticity printed circuit board gives printed circuit board good stretchability, and then obtains the printed circuit board that the bullet just combined, improves printed circuit board's reliability. And secondly, the rigid printed circuit board and the elastic printed circuit board are bonded through the first polysiloxane layer, so that the rigid printed circuit board can be firmly bonded on the surface of the elastic matrix of the elastic printed circuit board by virtue of the good reactivity of polysiloxane, and the reliability of the printed circuit board is further improved. Because the printed circuit board that this application provided has good elasticity and reliability concurrently, printed circuit board's application can further expand.

According to the preparation method of the printed circuit board, the polysiloxane material is combined on the bonding surface of the rigid printed circuit board and the elastic printed circuit prefabricated board, the rigid printed circuit board is firmly bonded on the surface of the elastic base body of the elastic printed circuit board by utilizing the good reactivity of the polysiloxane, and the reliability of the printed circuit board is further improved. The obtained printed circuit board has good rigidity for welding components and good stretchability, and the reliability of the printed circuit board can be improved by the stretchability.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

FIG. 1 is a flow chart of a process for manufacturing a printed circuit board according to an embodiment of the present disclosure;

fig. 2 is a schematic view illustrating a process for manufacturing a conductive circuit according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating a process for manufacturing a rigid printed circuit board according to an embodiment of the present disclosure;

FIG. 4 is a schematic flow chart of the preparation process of a flexible printed circuit prefabricated plate provided by the embodiment of the application;

fig. 5 is a schematic view of a process for manufacturing a printed circuit board according to an embodiment of the present disclosure.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In this application, the term "and/or" describes an association relationship of associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

In the present application, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (a), b, or c", or "at least one (a), b, and c", may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, and c may be single or plural, respectively.

It should be understood that, in various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, some or all of the steps may be executed in parallel or executed sequentially, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The terms "first" and "second" are used for descriptive purposes only and are used for distinguishing purposes such as substances, interfaces, messages, requests and terminals from one another and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. For example, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX, without departing from the scope of embodiments of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

In the description of the present application, it is to be understood that the terms "upper", "lower", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

A first aspect of embodiments of the present application provides a printed circuit board including a rigid printed circuit board and an elastic printed circuit board that are stacked and joined.

The rigid printed circuit board comprises a rigid substrate and a second conductive circuit layer combined on one side surface of the rigid substrate.

In one possible embodiment, the second conductive trace layer is a metal stack including two metal layers. In some embodiments, the second electrically conductive line layer includes a second copper line layer bonded to the rigid substrate, and a second nickel line layer disposed on a side surface of the second copper line layer facing away from the rigid substrate. In this case, the conductive circuit formed by the copper-nickel bimetal endows the rigid printed circuit board with better conductivity.

In one possible embodiment, the rigid printed circuit board further comprises glue for fixing the second conductive trace layer to the rigid substrate. The glue is arranged between the second conductive circuit layer and the rigid substrate and used for bonding the second conductive circuit layer on the rigid substrate. Illustratively, the glue is selected from epoxy glue.

In some embodiments, a glue layer is disposed between the second conductive circuit layer and the rigid substrate, the glue layer covers a side surface of the rigid substrate, and the second conductive circuit layer is disposed on a surface of the glue layer facing away from the rigid substrate. Namely, the glue layer is only combined with the surface of one side, facing the rigid substrate, of the second conductive circuit layer and does not extend to the side wall surface of the second conductive circuit layer and the surface of one side, facing away from the rigid substrate, of the second conductive circuit layer.

In some embodiments, in the rigid printed circuit board, a glue layer is disposed between the second conductive circuit layer and the rigid substrate, and the glue is filled between pattern gaps of the second conductive circuit layer, a plane of the glue layer departing from the rigid substrate is lower than a plane of the second conductive circuit layer departing from the rigid substrate, or the plane of the glue layer departing from the rigid substrate and a plane of the second conductive circuit layer departing from the rigid substrate are in the same plane. In this embodiment, the second conductive traces are partially embedded in an epoxy glue and affixed to the surface of the rigid substrate by the glue. In some embodiments, the plane of the adhesive layer departing from the rigid substrate and the plane of the second conductive circuit layer departing from the rigid substrate are in the same plane, so that the rigid printed circuit board with the flat surface on which the second conductive circuit layer is located is obtained, and the bonding performance between the rigid printed circuit board and the elastic printed circuit prefabricated board is improved.

In some embodiments, the rigid printed circuit board comprises a rigid substrate, an epoxy glue layer combined on one side surface of the rigid substrate, and a second conductive circuit layer combined on the surface of the epoxy glue layer, which faces away from the rigid substrate; the pattern gap of the second conductive circuit layer is filled with epoxy glue, and the plane of the epoxy glue layer departing from the rigid substrate is lower than the plane of the second conductive circuit layer departing from the rigid substrate, or the plane of the epoxy glue layer departing from the rigid substrate and the plane of the second conductive circuit layer departing from the rigid substrate are in the same plane. Illustratively, the plane of the epoxy glue layer departing from the rigid substrate and the plane of the second conductive circuit layer departing from the rigid substrate are in the same plane, so that the rigid printed circuit board with the flat surface on the surface of the second conductive circuit layer is obtained, and the bonding performance between the rigid printed circuit board and the elastic printed circuit prefabricated board is improved conveniently.

The printed circuit board that this application embodiment provided on the basis of rigidity printed circuit board, combines elasticity printed circuit board, on the one hand, can improve printed circuit board's elasticity, extends printed circuit board's application, and on the other hand can improve printed circuit board's reliability through addding elasticity printed circuit board.

The elastic printed circuit board comprises an elastic base body and a first conductive circuit layer combined on one side surface of the elastic base body. In one possible embodiment, the first conductive trace layer is a metal stack including two metal layers. In some embodiments, the first conductive trace layer includes a first copper trace layer bonded to the resilient base, and a first nickel trace layer disposed on a side surface of the first copper trace layer facing away from the resilient base. In this case, the conductive circuit formed by the copper-nickel bimetal endows the elastic printed circuit board with better conductivity.

In one possible implementation, the pattern gaps of the first conductive trace layer are filled with an elastic material. At this time, the copper layer extends to the surface of the elastic base body between the first conductive circuit layers, so that a continuous and complete film layer is formed on one side surface of the elastic printed circuit prefabricated board. In some embodiments, the pattern gap of the first conductive trace layer is filled with the same elastic material as the elastic base.

In some embodiments, the material of the elastomeric matrix is a silicone material. Illustratively, the silicone material is Polydimethylsiloxane (PDMS).

In a possible implementation manner, the material of the elastic base body is a silicone material, and a second polysiloxane layer is arranged between the elastic base body and the first conductive circuit layer. The second polysiloxane layer is used for increasing the adhesion of the first conductive circuit layer on the elastic base body, so that the first conductive circuit layer is firmly combined on the elastic base body. Specifically, the polysiloxane in the second polysiloxane layer has good reactivity, and forms a firm bonding interface through reaction with the silica gel material in the elastic base body, so that the first conductive circuit layer is firmly fixed on the elastic base body.

In some embodiments, the second silicone layer extends to the entire surface of the elastomeric body where the first electrically conductive line layers are disposed, i.e., the region of the elastomeric body between the first electrically conductive line layers, and is also provided with a silicone material. In this case, it is not necessary to prepare the second silicone layer for a specific region, so that the processability of the second silicone layer can be improved.

In some embodiments, the second polysiloxane layer has a thickness of less than or equal to 1 μm. When the thickness of the second polysiloxane layer exceeds 1 μm, the flexible printed circuit board is easily broken when bent due to certain brittleness of the polysiloxane.

In the embodiment of the application, the elastic printed circuit board and the rigid printed circuit board are combined to form the elastic-rigid combined integrated printed circuit board. Specifically, one side surface of the elastic base body in the elastic printed circuit board is bonded on one side surface of the second conductive circuit layer in the rigid printed circuit board through the first polysiloxane layer. In this case, the polysiloxane layer has good bonding properties with the elastic base and the metal layer, thereby improving the reliability of the printed circuit board.

In some embodiments, the pattern gap of the first conductive circuit layer of the rigid printed circuit board is filled with epoxy glue, the elastic base body of the elastic printed circuit board is made of a silica gel material, and the polysiloxane layer and the silica gel material have good reactivity and strong bonding capability with each other, so that the bonding strength between the elastic printed circuit board and the rigid printed circuit board is improved.

In some embodiments, the first polysiloxane layer has a thickness of less than or equal to 1 μm. When the thickness of the first polysiloxane layer exceeds 1 μm, the printed circuit board is easily broken when bent due to certain brittleness of the polysiloxane.

In some embodiments, the first polysiloxane layer has a thickness of less than or equal to 1 μm and the second polysiloxane layer has a thickness of less than or equal to 1 μm.

In some embodiments, the first conductive trace layer and the second conductive trace layer are metal stacks of two metal layers. The first conductive circuit layer comprises a first copper circuit layer combined on the elastic base body and a first nickel circuit layer arranged on the surface of one side, away from the elastic base body, of the first copper circuit layer; the second conductive circuit layer comprises a second copper circuit layer combined on the rigid base body and a second nickel circuit layer arranged on the surface of one side, away from the rigid base body, of the second copper circuit layer.

The printed circuit board provided by the embodiment of the application is provided with the metalized hole, and the metalized hole is used for communicating the first conductive circuit layer and the second conductive circuit layer, so that the circuit connection between the elastic printed circuit board and the rigid printed circuit board is realized. The placement and arrangement of the metallized holes are not critical. In some embodiments, the surface metal of the metallized hole is copper.

The printed circuit board that this application embodiment provided at first, combines rigid printed circuit board and elasticity printed circuit board to form same printed circuit board to make printed circuit board can weld components and parts on rigid printed circuit board, elasticity printed circuit board gives printed circuit board good stretchability, and then obtains the printed circuit board that the bullet just combines, improves printed circuit board's reliability. And secondly, the rigid printed circuit board and the elastic printed circuit board are bonded through the first polysiloxane layer, so that the rigid printed circuit board can be firmly bonded on the surface of the elastic matrix of the elastic printed circuit board by virtue of the good reactivity of polysiloxane, and the reliability of the printed circuit board is further improved. The printed circuit board provided by the embodiment of the application has good elasticity and reliability, so that the application field of the printed circuit board can be further expanded.

In a first aspect, embodiments of the present application provide a printed circuit board, which can be prepared by the following method.

Referring to fig. 1 and 2, a second aspect of embodiments of the present application provides a method of manufacturing a printed circuit board, the method including:

and S01, obtaining the rigid printed circuit board and the elastic printed circuit prefabricated board.

The rigid printed circuit board comprises a rigid substrate and a second conductive circuit layer combined on one side surface of the rigid substrate. In one possible embodiment, the second conductive trace layer is a metal stack including two metal layers. In some embodiments, the second electrically conductive line layer includes a second copper line layer bonded to the rigid substrate, and a second nickel line layer disposed on a side surface of the second copper line layer facing away from the rigid substrate. In this case, the conductive circuit formed by the copper-nickel bimetal endows the rigid printed circuit board with better conductivity.

In some embodiments, referring to fig. 3, the rigid printed circuit board includes a rigid substrate, an epoxy glue layer bonded to a surface of one side of the rigid substrate, and a second conductive trace layer bonded to a surface of the epoxy glue layer facing away from the rigid substrate, wherein pattern gaps of the second conductive trace layer are filled with the epoxy glue; the preparation method of the rigid printed circuit board comprises the following steps:

s0111, a second conducting circuit layer prefabricating sample is obtained and comprises a substrate, a copper layer combined on the surface of one side of the substrate and a second conducting circuit layer combined on the surface of one side, away from the substrate, of the copper layer.

Referring to fig. 5, in some embodiments, a method for preparing a pre-formed sample of a second conductive trace layer includes:

providing a substrate, wherein the substrate comprises an insulating film and a titanium foil combined on the surface of the insulating film;

electroplating a copper layer on the surface of the titanium foil, which is far away from the insulating film;

preparing a mask on the surface of the copper layer departing from the insulating film, wherein the pattern formed by the hollow area of the mask is consistent with the pattern of the second conductive circuit layer;

and electroplating a second conductive circuit layer in the hollow area of the mask, and removing the mask to obtain a second conductive circuit layer prefabricated sample.

In the embodiment, the titanium foil is used as a carrier base material, has good chemical stability, and is not corroded in acid electroplating solution and alkaline electroplating solution, so that the normal operation of electroplating operation is ensured. The insulating film is used as an insulating material to cover the surface of one side of the titanium foil, which deviates from the copper layer, so that metal is prevented from being deposited on the surface of the titanium foil in the electroplating process, the preparation efficiency of the second conducting circuit layer is reduced, and raw materials are wasted.

In some embodiments, before preparing the copper layer on the surface of the titanium foil, the method further comprises degreasing the titanium foil to prevent surface oil stains from affecting electroplating of metal salts, so as to improve thickness uniformity of the copper layer on the titanium foil.

In this example, the surface of the titanium foil facing away from the insulating film is plated with a copper layer. The copper layer serves as an intermediate layer and has low adhesion to the titanium foil, and the rigid circuit printed board can be obtained by peeling the copper layer from the titanium foil. Meanwhile, the copper layer is arranged on the surface of the titanium foil, so that the epoxy glue is prevented from being bonded to the titanium foil in the subsequent process of preparing the epoxy glue layer, and the epoxy glue bonded to the titanium foil is difficult to peel off due to the strong bonding force of the titanium foil and the epoxy glue.

On the titanium foil away from the insulating filmThe surface of the film is electroplated with a copper layer using conventional electroplating solutions and conditions. In some embodiments, an acidic copper electroplating bath is configured, the acidic copper electroplating bath comprising: 220g/L of copper sulfate pentahydrate, 65g/L of sulfuric acid, 60mg/L of copper chloride and 1g/L of polyethylene glycol 1500; placing the substrate as anode into acidic copper electroplating solution, depositing copper at room temperature, and controlling current density at 5A/dm²After 5 minutes, a thin copper layer of several micrometers was formed on the surface of the titanium foil.

And (4) washing the copper layer by using deionized water after the copper layer is prepared, removing the electroplating solution, and drying.

The mask is prepared on the surface of the copper layer away from the insulating film by adopting a common photoetching process.

In some embodiments, electroplating a second conductive circuit layer in the hollow area of the mask, where the second conductive circuit layer is a conductive circuit layer formed by stacking a copper conductive circuit layer and a nickel conductive circuit layer, and the copper plating electrolyte is an acidic copper plating electrolyte, including: 220g/L of copper sulfate pentahydrate, 65g/L of sulfuric acid, 60mg/L of copper chloride and 1g/L of polyethylene glycol 1500; the nickel plating electrolyte is nickel sulfamate electroplating solution: 450g/L of nickel sulfamate tetrahydrate, 30g/L of boric acid and 0.4g/L of sodium dodecyl sulfate. The method for electroplating the second conductive circuit layer in the hollow area of the mask comprises the following steps:

putting the carrier titanium foil as an anode into an electrolytic nickel plating solution, depositing nickel at 50 ℃, and controlling the current density to be 5A/dm²Nickel is deposited on the exposed circuit pattern area (the hollow area of the mask), and after a certain period of time, an electroplated nickel layer with a required thickness is formed. After cleaning, the substrate is taken as an anode and put into acid copper electroplating solution for copper deposition under the condition of normal temperature, and the current density is controlled to be 5A/dm²And the copper can be continuously deposited on the surface of the electroplated nickel layer, and an electroplated copper layer with the required thickness is formed after a certain period of time. And after the electroplating is finished, washing the mask by using a specific photoresist removing liquid to obtain the required second conducting circuit.

In some embodiments, the mask is an electroplating-resistant photosensitive mask, such that mask properties are maintained while conductive lines are grown.

S0112, forming an epoxy glue layer on the surface where the second conducting circuit is located in the second conducting circuit layer prefabricated sample, and adhering the rigid base body through the epoxy glue layer; s0113, after the titanium foil is stripped, the copper layer is removed through etching, and the rigid printed circuit board is obtained.

In an embodiment of the application, the flexible printed circuit board includes a flexible substrate and a first conductive trace layer coupled to a surface of one side of the flexible substrate. The elastic printed circuit prefabricated board is an elastic printed circuit board with a copper layer combined on the surface of one side of a first conductive circuit layer of the elastic printed circuit board. The elastic printed circuit prefabricated board comprises an elastic base body, a first conductive circuit layer and a copper layer, wherein the first conductive circuit layer is combined on the surface of one side of the elastic base body, the copper layer is combined on the surface, deviating from the elastic base body, of the first conductive circuit layer, and the copper layer extends to the surface, between the first conductive circuit layers, of the elastic base body.

In one possible embodiment, the first conductive trace layer is a metal stack including two metal layers. In some embodiments, the first conductive trace layer includes a first copper trace layer bonded to the resilient base, and a first nickel trace layer disposed on a side surface of the first copper trace layer facing away from the resilient base. In this case, the conductive circuit formed by the copper-nickel bimetal endows the elastic printed circuit board with better conductivity. In some embodiments, the first copper line layer has a thickness of 3-40um and the first nickel line layer has a thickness of 1-10 um.

Referring to fig. 4, in some embodiments, the elastomeric printed circuit pre-sheet further comprises a second layer of silicone disposed between the elastomeric base and the first layer of electrically conductive traces; the preparation method of the elastic printed circuit prefabricated board comprises the following steps:

s0121, obtaining a first conducting circuit layer prefabrication sample, wherein the first conducting circuit layer prefabrication sample comprises a substrate, a copper layer combined on the surface of one side of the substrate and a first conducting circuit layer combined on the surface of one side, away from the substrate, of the copper layer.

Referring to fig. 5, in some embodiments, a substrate includes an insulating film and a titanium foil bonded to a surface of the insulating film, a copper layer has a thickness of 1 to 10 μm, and a method of preparing a first conductive trace layer preform includes:

preparing a mask on the surface of the copper layer departing from the insulating film, wherein the pattern formed by the hollow area of the mask is consistent with the pattern of the first conductive circuit layer;

and electroplating a first conductive circuit layer in the hollow area of the mask, and removing the mask to obtain a first conductive circuit layer prefabricated sample.

In the embodiment, the titanium foil is used as a carrier base material, has good chemical stability, and is not corroded in acid electroplating solution and alkaline electroplating solution, so that the normal operation of electroplating operation is ensured. The insulating film is used as an insulating material to cover the surface of one side of the titanium foil, which deviates from the copper layer, so that metal is prevented from being deposited on the surface of the titanium foil in the electroplating process, the preparation efficiency of the first conducting circuit layer is reduced, and raw materials are wasted.

In this embodiment, a thin layer of copper is electroplated on the surface of the titanium foil facing away from the insulating film. The copper layer is arranged on the surface of the titanium foil, so that in the subsequent process of preparing the second polysiloxane layer, the second polysiloxane is prevented from being directly contacted with the titanium foil and bonded to the titanium foil, and the second polysiloxane bonded to the titanium foil is difficult to peel off due to the strong bonding force of the titanium foil and the second polysiloxane. In addition, in the electroplating thickening process of the metallized holes, the copper layer serves as a conducting layer of each hole, and the simultaneous electroplating thickening of all the holes can be realized.

In this example, the surface of the titanium foil facing away from the insulating film is plated with a copper layer. The copper layer is arranged on the surface of the titanium foil, so that the epoxy glue is prevented from being combined on the titanium foil in the subsequent process of preparing the epoxy glue layer. The epoxy glue bonded to the titanium foil is difficult to peel off due to the strong bonding force of the titanium foil and the epoxy glue.

Electroplating the copper layer on the surface of the titanium foil, which is far away from the insulating film, can be realized by adopting conventional electroplating solution and electroplating conditions. In some embodiments, an acidic copper electroplating bath is configured, the acidic copper electroplating bath comprising: 220g/L of copper sulfate pentahydrate, 65g/L of sulfuric acid, 60mg/L of copper chloride and 1g/L of polyethylene glycol 1500; placing the substrate as anode into acidic copper electroplating solution, depositing copper at room temperature, and controlling current density at 5A/dm²After 5 minutes, a film of several micrometers was formed on the surface of the titanium foilA copper layer.

In some embodiments, the mask is an electroplating-resistant photosensitive mask, such that mask properties are maintained while conductive lines are grown. The mask is prepared on the surface of the copper layer away from the insulating film by adopting a common photoetching process.

In some embodiments, electroplating a first conductive circuit layer in the hollow area of the mask, where the first conductive circuit layer is a conductive circuit layer formed by stacking a copper conductive circuit layer and a nickel conductive circuit layer, and the copper plating electrolyte is an acidic copper plating electrolyte, including: 220g/L of copper sulfate pentahydrate, 65g/L of sulfuric acid, 60mg/L of copper chloride and 1g/L of polyethylene glycol 1500; the nickel plating electrolyte is nickel sulfamate electroplating solution: 450g/L of nickel sulfamate tetrahydrate, 30g/L of boric acid and 0.4g/L of sodium dodecyl sulfate. The method for electroplating the second conductive circuit layer in the hollow area of the mask comprises the following steps:

putting the carrier titanium foil as an anode into an electrolytic nickel plating solution, depositing nickel at 50 ℃, and controlling the current density to be 5A/dm²Nickel is deposited on the exposed circuit pattern area (the hollow area of the mask), and after a certain period of time, an electroplated nickel layer with a required thickness is formed. After cleaning, the substrate is taken as an anode and put into acid copper electroplating solution for copper deposition under the condition of normal temperature, and the current density is controlled to be 5A/dm²And the copper can be continuously deposited on the surface of the electroplated nickel layer, and an electroplated copper layer with the required thickness is formed after a certain period of time. And after the electroplating is finished, washing the mask by using a specific photoresist removing liquid to obtain the required first conductive circuit.

S0122, preparing a second polysiloxane layer on the side surface of the first conducting circuit layer prefabricated sample.

In this embodiment, the second polysiloxane layer is prepared on the surface of the first conductive circuit layer by spraying, dipping, ink-jetting, and the like.

S0123, after the surface of the second polysiloxane layer is treated, preparing an elastic matrix on the surface of the second polysiloxane layer.

In this example, the second polysiloxane layer was surface activated by plasma treatment. In some embodiments, preparing the elastomeric matrix on the surface of the second silicone layer comprises: and pouring a silica gel precursor on the surface of the second polysiloxane layer, heating and curing the silica gel, and tightly bonding the cured silica gel with the first conducting circuit layer. Further, directly peeling off the silica gel, and transferring the thin copper layer, the thin nickel layer and the copper layer onto the silica gel to obtain the elastic printed circuit prefabricated board.

In some embodiments, the surface treatment is a plasma treatment to enrich the hydroxyl groups on the surface of the second polysiloxane layer to promote reaction between the polysiloxane and the elastomeric matrix, thereby increasing the bonding strength of the conductive traces on the elastomeric matrix.

Preparing an elastic matrix on the surface of the second polysiloxane layer, wherein the elastic matrix is preferably a PDMS elastomer.

And S0124, stripping the substrate to obtain the elastic printed circuit prefabricated board.

And S02, adhering the surface of one side of the elastic base body in the elastic printed circuit board prefabricated board to the surface of one side of the second conductive circuit layer in the rigid printed circuit board through a polysiloxane material to obtain the prefabricated printed circuit board.

Through the polysiloxane material, the elastic printed circuit board and the rigid printed circuit board can be directly combined to prepare the printed circuit board with the elastic and rigid combination, circuits on the elastic printed circuit board and the rigid printed circuit board can be connected through metallized through holes, components can be welded on the rigid board, and the elastic board is responsible for providing stretchability, so that the reliability of the high printed circuit board is obtained. The silicone material used to bond the elastomeric printed circuit board preformed sheet and the rigid printed circuit board forms a first silicone layer.

In one possible embodiment, the matrix unit of the polysiloxane material is selected from a siloxane compound or a siloxane compound prepolymer containing at least one of an amine group, a mercapto group, an epoxy group, a hydroxyl group, a carboxyl group, and an alkyl group. Exemplary base units of the polysiloxane material include, but are not limited to, triethoxysilane, trimethoxy silane, trichlorosilane, diethoxy silane, dimethoxy silane, dichloro silane, monoethoxy silane, monomethoxy silane, monochlorosilane, tetraethoxy silane, tetramethoxy silane, tetrachloro silane, or a prepolymer (a partial hydrolysate of the polysiloxane material) containing one or more of amine, mercapto, epoxy, methyl, ethyl, hydroxyl, carboxyl, hydrogen.

In the embodiment of the application, the surface of one side of the elastic base body in the elastic printed circuit prefabricated board is bonded on the surface of one side of the second conductive circuit layer in the rigid printed circuit board through the polysiloxane material, and the method comprises the following steps: and coating a polysiloxane material on the surface of one side of the second conductive circuit layer in the rigid printed circuit board to prepare a first polysiloxane layer. The coating method is not particularly limited as long as the polysiloxane material can be formed on the surface of the medium, and includes, but is not limited to, knife coating, spin coating, and printing.

In some embodiments, the method of bonding a surface of the elastic base body of the elastic printed circuit board on a surface of the second conductive wiring layer of the rigid printed circuit board by a silicone material to obtain a prefabricated printed circuit board includes:

coating a polysiloxane material on the surface of one side of a second conductive circuit layer of the rigid printed circuit board to obtain a first polysiloxane coating;

and carrying out plasma treatment on the surfaces of the first polysiloxane coating and the elastic matrix in the elastic printed circuit prefabricated board, and bonding one side surface of the elastic matrix in the elastic printed circuit prefabricated board on the first polysiloxane layer to obtain the prefabricated printed circuit board.

The surface of one side of the second conducting circuit layer in the rigid printed circuit board is coated with the polysiloxane material, and when the first polysiloxane layer is prepared, the polysiloxane material has reactivity with glue, particularly a silica gel material, and has a certain adhesive force with a metal material of the second conducting circuit layer, so that the mode is favorable for improving the binding force between the elastic printed circuit prefabricated board and the rigid printed circuit prefabricated board.

In some embodiments, the surface on the side of the elastic base in the flexible printed circuit board is bonded to the surface on the side of the second conductive wiring layer in the rigid printed circuit board through the first silicone layer, or the surface on the side of the second conductive wiring layer in the rigid printed circuit board is bonded to the surface on the side of the flexible base in the flexible printed circuit board through the first silicone layer, and thereafter, the bonding reaction between the first silicone layer and the bonding interface is promoted by a heat press treatment at a temperature of 80 to 150 ℃.

And S03, in a preset punching area, punching the prefabricated printed circuit board to form a hole.

In this step, the prefabricated printed circuit board is cut using an ultraviolet laser cutting or mechanical punching method to form a hole. Illustratively, the holes are blind holes or through holes.

The prefabricated printed circuit board is punched, and the punching can be started from one side of the rigid printed circuit board or the elastic printed circuit board. In some embodiments, the copper layer and the elastomeric substrate are cut from one side of the elastomeric printed circuit board using an ultraviolet laser cutter, and the hole is formed by ablating the copper layer and the elastomeric substrate.

And S04, preparing a metal layer on the wall surface of the hole to obtain the metallized hole.

And preparing a metal layer on the wall surface of the hole by adopting a method of combining chemical plating with electroplating. Specifically, the wall surface of the hole is activated, then a metal layer is grown on the wall surface of the hole by chemical plating, and the thickness of the metal layer is further increased by electroplating. Compared with the method for metallizing holes by screen printing, the method for metallizing holes by combining chemical plating with electroplating has the advantages that the process is simple, special equipment, screens or masks are not needed, and printed circuit boards with different conducting wires can be prepared. The conductivity of the metallized through hole is related to the chemical plating solution and the electroplating solution, generally approaches to the resistivity of the corresponding bulk metal, and the actual resistance is far lower than that of the solder paste, so that the overall performance of the printed circuit board can be improved.

In one possible embodiment of the present invention, preparing a metal layer on a wall surface of a hole to obtain a metallized hole includes:

and S041, preparing a third polysiloxane layer on the wall surface of the hole, and carrying out sensitization treatment and activation treatment on the wall surface of the hole.

In the step, a third polysiloxane layer is prepared on the wall surface (hole wall) of the hole, and the surface of the hole wall obtains hydrophilic and chemical reaction sites through the third polysiloxane layer, so that a catalytic center can be adsorbed on the sites in the sensitization and activation processes and cannot fall off, and further, in the chemical plating process, the combination of metal on the wall surface of the hole is promoted, and the hole metallization is facilitated.

In some embodiments, the third polysiloxane layer is prepared on the wall surface of the hole, and can be realized by dip coating, spray coating or ink jet.

In some embodiments, the sensitizing agent is stannous chloride and the activating agent is palladium chloride. In some embodiments, the sensitization and activation of the walls of the holes comprises: immersing the sample piece with the third polysiloxane layer prepared on the surface of the hole wall into a stannous chloride solution for sensitization treatment, taking out and cleaning with deionized water; then, the substrate was immersed in a palladium chloride solution to perform an activation treatment, taken out, and washed with deionized water. In some embodiments, the concentration of the sensitized stannous chloride solution is 10g/L and the sensitization time is 10 minutes; the concentration of the palladium chloride solution subjected to the activation treatment was 0.5g/L, and the activation time was 10 minutes.

In some embodiments, before preparing the third polysiloxane layer on the wall surface of the hole, plasma treatment is further performed on the wall surface of the hole to improve the adhesion of the third polysiloxane layer on the wall surface.

S042, performing surface chemical plating on the third polysiloxane layer to obtain a metal thin layer.

In the step, the whole copper layer in the elastic printed circuit prefabricated board is used as a conducting layer of all holes, and meanwhile, chemical plating of all holes is achieved. In some embodiments, the electroless plating solution is a plating solution comprising: 10g/L of sodium hydroxide, 18g/L of trisodium citrate, 30g/L of boric acid, 6g/L of copper sulfate, 0.5g/L of nickel sulfate and 30g/L of sodium hypophosphite. In some embodiments, a method of electroless plating, comprises: and placing the activated sample piece in a chemical plating solution at 65 ℃ for copper deposition, and depositing a copper layer with a certain thickness on the wall surface of the hole.

And S043, electroplating the thickened metal thin layer to obtain a metal layer, and thus obtaining the metallized hole.

After the thin metal layer is obtained, all metal on the hole wall is thickened in an electroplating mode, the hole resistance is reduced, and the reliability is improved. In the step, the whole copper layer in the elastic printed circuit prefabricated board is used as a conducting layer of all holes, and electroplating thickening of all the holes is realized simultaneously, so that metallization treatment of all the holes of the prefabricated printed circuit board is completed at one time, the minimum metallized holes of 50um or below can be prepared theoretically, and plating of various high-conductivity metals can be realized.

In some embodiments, the plating solution for electroplating is a plating solution comprising: 10g/L of sodium hydroxide, 18g/L of trisodium citrate, 30g/L of boric acid, 6g/L of copper sulfate, 0.5g/L of nickel sulfate and 30g/L of sodium hypophosphite. In some embodiments, a method of electroplating, comprises: and (3) putting the sample piece subjected to chemical plating into a plating solution at 65 ℃ for copper enrichment, growing a copper layer on the wall surface of the hole, and increasing the thickness of the copper layer.

According to the embodiment of the invention, hole metallization is carried out based on a chemical plating and electroplating mode, and through special pretreatment, the elastic silica gel base material can be plated with high-conductivity metals such as copper, nickel and the like through the process.

And S05, removing the copper layer on the surface of the elastic printed circuit board prefabricated board to obtain the printed circuit board.

After the hole-metallizing step is completed, the copper layer needs to be removed to avoid the copper layer from affecting the working performance of the printed circuit board.

In some embodiments, the copper layer on the surface of the flexible printed circuit board preform is removed by etching. In some embodiments, the first conductive circuit layer comprises a first copper circuit layer combined on the elastic base body and a first nickel circuit layer arranged on one side surface of the first copper circuit layer, which is far away from the elastic base body, in this case, when the copper layer on the surface of the elastic printed circuit board prefabricated plate is removed by etching, the copper layer on the surface of the elastic printed circuit board prefabricated plate can be removed by etching by the etching liquid, and the first copper circuit layer is protected by the first nickel circuit layer and cannot be removed by etching, so that the conductive circuit with high conductivity is reserved.

The following description will be given with reference to specific examples.

A method of manufacturing a printed circuit board, comprising:

referring to fig. 2, preparation of conductive lines: a metal titanium foil with the thickness of 50 mu m is used as a carrier base material, and an insulating material is bonded on one side surface of the titanium foil to obtain the carrier titanium foil. After the carrier titanium foil is subjected to oil removal treatment, the carrier titanium foil is used as a cathode and is put into an acid copper electroplating solution, and the current density is controlled to be 5A/dm at normal temperature²The deposition of copper was carried out under the conditions of (1), and after 5 minutes, a copper layer of several micrometers was formed by electroplating on the surface of the titanium foil. Wherein, the copper layer electroplating solution is an acid copper electroplating solution, which comprises: 220g/L of copper sulfate pentahydrate, 65g/L of sulfuric acid, 60mg/L of copper chloride and 1g/L of polyethylene glycol 1500. And washing the copper layer by using deionized water, drying, preparing a mask on the surface of the copper layer by using a photoetching process, and hollowing out the part corresponding to the circuit pattern to be prepared. Placing carrier titanium foil containing mask as cathode in nickel plating solution, controlling current density at 5A/dm at 50 deg.C²Depositing nickel on the hollow area of the mask to form an electroplated nickel layer. Wherein, the plating solution of the electroplated nickel is nickel sulfamate plating solution, which comprises the following components: 450g/L of nickel sulfamate tetrahydrate, 30g/L of boric acid and 0.4g/L of sodium dodecyl sulfate. And (4) cleaning, then electroplating copper for deposition, continuously depositing copper on the surface of the electroplated nickel layer, and forming an electroplated copper layer after a certain period of time. The plating solution for copper electroplating is the acidic copper electroplating solution described above. Use of special features after completion of electroplatingThe mask is washed away by the photoresist removing liquid, and the required conductive circuit is obtained.

Preparation of polysiloxane coating: 6g of 3-Aminopropyltriethoxysilane (3-Aminopropyltriethoxysilane, APTES), 2g of 3-Mercaptopropyltriethoxysilane (3-Mercaptopropylthysilane, MPTES), 0.2g of ethanol, 0.6g of methanol, 0.2g of acetylacetone and 1g of water were placed in a closed flask and stirred at room temperature for 18 hours to obtain a polysiloxane solution. And (3) diluting by using ethanol/acetone as a solvent in a mass ratio of 13:5 to obtain the polysiloxane coating with the mass fraction of 10%.

Preparing the elastic-rigid combined printed circuit board: selecting Sylgard 184PDMS for Dow Corning, uniformly mixing the component A and the component B according to the mass ratio of 10:1, vacuumizing to remove bubbles in liquid, and standing at normal temperature for later use. Referring to fig. 3, the conductive traces required by the rigid printed circuit board are bonded to the rigid substrate by epoxy glue, and are hot-pressed by a hot press at 80 ℃, so that air at the interface is extruded out to enable the copper layer and the conductive traces to be in more complete contact with the rigid substrate. Next, the rigid substrate was peeled from one end of the titanium foil at an angle of about 90 degrees, and the copper layer on the titanium foil and the conductive wiring were transferred to the rigid substrate. And (3) immersing the sample stripped of the titanium foil into a copper etching solution, wherein the components of the etching solution are 100g/L of copper chloride dihydrate, 100g/L of ammonium chloride and 700ml/L of ammonia water, controlling the etching temperature to be 50 ℃, completely removing the copper layer, cleaning and drying to obtain the required rigid printed circuit board.

Referring to fig. 4, polysiloxane paint is uniformly sprayed on the surface of the conductive circuit required by the prepared elastic printed circuit board, and then the elastic printed circuit board is placed in an oven at 80 ℃ to be dried for 30 minutes so as to volatilize the solvent and solidify the coating, and a polysiloxane coating is formed on the surfaces of the conductive circuit and the copper layer. And then putting the conductive circuit into a plasma cleaning machine to carry out hydroxylation treatment on the surface of the coating for 20s, covering the prepared PDMS solution on the surfaces of the conductive circuit and the copper layer in a spin coating mode after the treatment is finished, and placing the conductive circuit and the copper layer in an oven at 80 ℃ to heat for 30 minutes to completely cure the conductive circuit and the copper layer. And then, peeling off the PDMS substrate from one end of the titanium foil, wherein the peeling angle is about 90 degrees, and the thin copper layer and the conductive circuit on the titanium foil are transferred to the PDMS substrate to obtain the elastic printed circuit prefabricated board.

Referring to fig. 5, a polysiloxane coating is uniformly sprayed on one surface of the rigid printed circuit board having the conductive circuit, and the rigid printed circuit board is placed in an oven at 80 ℃ to be dried for 30 minutes so that the solvent is volatilized, the coating is cured, and a polysiloxane coating is formed on the surface of the conductive circuit. After curing, putting the cured elastic printed circuit board and the elastic printed circuit board into a plasma cleaning machine for hydroxylation treatment for 20s, quickly bonding the surface of the elastic printed circuit prefabricated board without the conducting circuit and the surface of the rigid printed circuit board with the conducting circuit at a designed position after the treatment is finished, and carrying out hot pressing at 80 ℃ through a hot press to enable the interface reaction to be more thorough. And (2) performing laser drilling at a designated position, cutting the thin copper layer and the PDMS base material from one side of the elastic printed circuit prefabricated plate by using an ultraviolet laser cutting machine, ablating the thin copper layer and the PDMS base material to obtain a blind hole, then putting the blind hole into a plasma cleaning machine to perform hydroxylation treatment on the hole wall of the blind hole, quickly immersing the blind hole into polysiloxane coating after the treatment is completed, taking out the blind hole, and drying the blind hole in an oven at 80 ℃ for 30 minutes. And (3) after the coating is cured, immersing the blind hole into a stannous chloride solution of 10g/L for sensitization treatment, taking out after 10 minutes and washing with deionized water, then immersing into a palladium chloride solution of 0.5g/L for activation treatment, and taking out after 10 minutes and washing with deionized water. Placing the sensitized and activated blind hole in chemical copper plating solution at 65 ℃ for copper deposition, wherein the plating solution formula is as follows: 10g/L of sodium hydroxide, 18g/L of trisodium citrate, 30g/L of boric acid, 6g/L of copper sulfate, 0.5g/L of nickel sulfate and 30g/L of sodium hypophosphite. After plating for a certain time, depositing a copper layer with a certain thickness on the hole wall, thickening the hole wall plating layer in an electroplating mode, and finally etching the thin copper layer on the surface of the elastic printed circuit prefabricated board to form the required elastic-rigid combined printed circuit board.

The elastic-rigid combined printed circuit board prepared by the embodiment is used, the switch and the power supply are welded on the rigid printed circuit board, the LED lamp is welded on the elastic printed circuit board, the maximum stretching rate of the horseshoe-shaped conductive circuit can reach 80%, the resistance does not change obviously, and the LED lamp can be lightened all the time.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A printed circuit board is characterized by comprising a rigid printed circuit board and an elastic printed circuit board which are combined in a laminated mode, wherein the elastic printed circuit board comprises an elastic base body and a first conductive circuit layer combined on one side surface of the elastic base body; the rigid printed circuit board comprises a rigid substrate and a second conductive circuit layer combined on one side surface of the rigid substrate;

the printed circuit board is provided with a metalized hole, and the metalized hole is used for communicating the first conductive circuit layer and the second conductive circuit layer.

2. The printed circuit board of claim 1, wherein the elastomeric body is formed from a silicone material, and a second silicone layer is disposed between the elastomeric body and the first conductive trace layer.

3. The printed circuit board of claim 2, wherein the first polysiloxane layer has a thickness of less than or equal to 1 μ ι η; and/or

The second polysiloxane layer has a thickness of less than or equal to 1 μm.

4. A printed circuit board according to any one of claims 1 to 3, wherein the first conductive wiring layer comprises a first copper wiring layer bonded to the elastic base, and a first nickel wiring layer provided on a side surface of the first copper wiring layer facing away from the elastic base; and/or

The second conductive circuit layer comprises a second copper circuit layer combined on the rigid base body and a second nickel circuit layer arranged on the surface of one side, away from the rigid base body, of the second copper circuit layer.

5. A method for manufacturing a printed circuit board, the method comprising:

6. The method of manufacturing a printed circuit board according to claim 5, wherein the step of forming a metal layer on the wall surface of the hole to form a metallized hole comprises:

preparing a third polysiloxane layer on the wall surface of the hole, and then carrying out sensitization treatment and activation treatment on the wall surface of the hole;

performing surface chemical plating on the third polysiloxane layer to obtain a metal thin layer;

and electroplating to thicken the metal thin layer to obtain a metal layer, and thus obtaining the metallized hole.

7. The method of manufacturing a printed circuit board according to claim 6, wherein the flexible printed circuit board further comprises a second silicone layer disposed between the flexible substrate and the first conductive trace layer; the preparation method of the elastic printed circuit prefabricated plate comprises the following steps:

preparing a second polysiloxane layer on the side surface of the first conducting circuit layer prefabricated sample;

after the second polysiloxane layer is subjected to surface treatment, preparing an elastic matrix on the surface of the second polysiloxane layer;

8. The method for manufacturing a printed circuit board according to claim 7, wherein the substrate comprises an insulating film and a titanium foil bonded to a surface of the insulating film, the copper layer has a thickness of 1 to 10 μm, and the first conductive wiring line layer preform is prepared by:

electroplating the copper layer on the surface of the titanium foil, which is far away from the insulating film;

preparing a mask on the surface of the copper layer, which is far away from the insulating film, wherein the pattern formed by the hollow area of the mask is consistent with the pattern of the first conductive circuit layer;

9. The method for producing a printed circuit board according to any one of claims 5 to 8, wherein the step of bonding a surface of the elastic base body of the elastic printed circuit board preform to a surface of the second conductive wiring layer of the rigid printed circuit board by a silicone material to obtain a preform printed circuit board comprises:

coating the polysiloxane material on the surface of one side of the second conducting circuit layer of the rigid printed circuit board to obtain a first polysiloxane coating;

10. A method for preparing a printed circuit board according to any one of claims 5 to 7, wherein the structural monomer of the polysiloxane material is selected from a siloxane compound containing at least one of an amine group, a mercapto group, an epoxy group, a hydroxyl group, a carboxyl group, and an alkyl group, or a prepolymer of the siloxane compound.