CN113438830A

CN113438830A - Circuit board and preparation method thereof

Info

Publication number: CN113438830A
Application number: CN202110775296.4A
Authority: CN
Inventors: 李金明
Original assignee: Jiangxi Roushun Technology Co ltd
Current assignee: Jiangxi Hongmei New Energy Technology Co ltd
Priority date: 2021-07-08
Filing date: 2021-07-08
Publication date: 2021-09-24

Abstract

The invention discloses a preparation method of a circuit board, which comprises the following steps: (1) preparing a conductive copper layer on the surface of a carrier layer, wherein the carrier layer comprises a base material layer and a stripping layer, the conductive copper layer is prepared on the surface of the stripping layer, and the conductive copper layer is etched to form a circuit layer; (2) the carrier layer and the circuit layer form a material supply roll; (3) and feeding the heat-conducting glue solution to the surface of a feeding roll conveyed by a first unwinding device, drying the heat-conducting glue solution by a drying device, and then attaching the heat-conducting glue solution to a feeding roll conveyed by a second unwinding device, so that the two feeding rolls and the heat-conducting glue solution positioned between the two feeding rolls jointly enter between two hot pressing devices, forming an insulating layer after hot pressing, and preparing a thickened copper layer on the surface of the circuit layer after peeling off a carrier layer. The process can realize the copper clad laminate with a thin copper layer, avoid the thin copper from being pulled to be easy to break, realize accurate etching, obtain the circuit board with narrow line width, improve the binding force between the copper layer and the insulating layer, obtain the circuit board with good heat dissipation, and has the advantages of simple process, low cost and improvement of production efficiency and yield.

Description

Circuit board and preparation method thereof

Technical Field

The invention relates to the technical field of circuit board preparation, in particular to a circuit board with a heat dissipation effect and a preparation method thereof.

Background

Pcb (printed circuit board), i.e. printed wiring board, printed circuit board for short, is one of the important parts in the electronics industry. Almost every kind of electronic equipment, as small as electronic watches, calculators, as large as computers, communication electronics, military weaponry systems, has electronic components such as integrated circuits, and printed boards are used to electrically interconnect the various components. The printed circuit board consists of an insulating bottom plate, a connecting lead and a welding disc for assembling and welding electronic elements, and has double functions of a conductive circuit and the insulating bottom plate. The circuit can replace complex wiring to realize electrical connection among elements in the circuit, thereby simplifying the assembly and welding work of electronic products, reducing the wiring workload in the traditional mode and greatly lightening the labor intensity of workers; and the volume of the whole machine is reduced, the product cost is reduced, and the quality and the reliability of the electronic equipment are improved. The printed circuit board has good product consistency, can adopt standardized design, and is beneficial to realizing mechanization and automation in the production process. Meanwhile, the whole printed circuit board subjected to assembly and debugging can be used as an independent spare part, so that the exchange and maintenance of the whole product are facilitated. At present, printed wiring boards have been used very widely in the manufacture of electronic products.

Electronic products can generate heat in a large amount under long-term work, and if heat is not dissipated in time, functions of the electronic products are at risk of failure. When the existing PCB works in a power-on mode, IC chips and components welded on the PCB are prone to heating, heat is prone to gathering on welding discs of the IC chips and the components, and damage to the IC chips and the components is caused. In traditional heat conduction double-sided circuit board, generally for carrying out the heat conduction through polyimide film and the epoxy glue of heat conduction, some will add the heat conduction material. For the preparation of the circuit board, the above materials are usually coated on the surface of a copper foil, then another copper foil is used for bonding, hot press molding is carried out, and then a circuit is manufactured by etching through the traditional circuit manufacturing technology. However, the bonding force between the insulating substrate and the copper layer obtained by the manufacturing method is insufficient, so that the copper layer is easy to separate, and the quality of the product is affected.

Therefore, it is necessary to provide a circuit board and a method for manufacturing the same to solve the above drawbacks.

Disclosure of Invention

One of the purposes of the invention is to provide a preparation method of a circuit board, which can realize a copper-clad plate with a thin copper layer, is beneficial to etching, can improve the bonding force between the copper layer and an insulating layer, can obtain a circuit board with good heat dissipation, has simple process and low cost, and can improve the production efficiency and yield.

The invention also aims to provide a circuit board, wherein the copper layer and the insulating layer have good bonding force and good high-temperature resistance and heat resistance.

In order to achieve the purpose, the invention discloses a preparation method of a circuit board, which comprises the following steps:

(1) providing a carrier layer, preparing a conductive copper layer on the surface of the carrier layer, wherein the carrier layer comprises a base material layer and a stripping layer prepared on the surface of the base material layer, preparing the conductive copper layer on the surface of the stripping layer, and etching the conductive copper layer to form a circuit layer;

(2) the carrier layer and the circuit layer form a material supply roll;

(3) a hot pressing device, a first unreeling device, a second unreeling device, a first reeling device, a second reeling device and a drying device are provided,

the first unreeling device and the second unreeling device are sequentially arranged in a front-back mode along the conveying direction, the drying device is located between the first unreeling device and the second unreeling device,

providing two material supply rolls, wherein the first unwinding device unwinds one material supply roll, the second unwinding device unwinds the other material supply roll, the two material supply rolls are respectively fed between the two symmetrically-arranged hot pressing devices, and the conductive copper layers of the two material supply rolls are far away from the hot pressing devices and are oppositely arranged;

the first winding device is used for winding the carrier layer, and the second winding device is used for winding a product;

feeding heat-conducting glue solution to the surface of the material supply roll conveyed by the first unreeling device, drying the material supply roll by the drying device, and attaching the material supply roll conveyed by the second unreeling device to the material supply roll, so that the two material supply rolls and the heat-conducting glue solution between the two material supply rolls jointly enter between the two hot pressing devices, and forming an insulating layer after hot pressing,

and after the carrier layer is stripped, preparing a thickened copper layer on the surface of the circuit layer with the insulating layer exposed.

Compared with the prior art, the preparation method of the circuit board adopts the carrier layer as the bearing to prepare the conductive copper layer, can prepare the thinner conductive copper layer, is convenient to etch and low in cost, is accurate to etch, obtains the circuit board with narrower line width, and can improve the utilization rate of the circuit board and increase the data transmission effect. The base material layer is peeled by the aid of the peeling layer, the carrier layer is wound by the aid of the first winding device to peel the carrier layer, the product is wound by the second winding device, the heat-conducting glue solution between the two circuit layers is dried by the drying device and then is subjected to hot-pressing curing treatment by the hot-pressing device to form the insulating layer, and the insulating layer and the circuit layers are embedded into each other, so that the bonding force between the insulating layer and the circuit layers is improved, and the heat-conducting glue solution endows the circuit boards with a good heat-conducting effect. The process avoids the situation that the thin copper is easy to break due to tension, and realizes high yield and high yield of the circuit board.

Preferably, the substrate layer is selected from a metal substrate or a non-metal substrate.

Preferably, the metal substrate is selected from copper, aluminum or stainless steel.

Preferably, the thickness of the conductive copper layer is 0.5 μm to 18 μm.

Preferably, the heat-conducting glue solution comprises glue stock, heat-conducting powder and a solvent.

Preferably, the sizing material is at least one selected from epoxy resin, MPI and silica gel, or a nitrile rubber and epoxy resin composite rubber.

Preferably, the conductive copper layer is prepared on the surface of the stripping layer by means of vacuum magnetron sputtering, chemical plating, water electroplating or chemical copper deposition.

Preferably, a metal layer is prepared on the surface of the carrier layer through vacuum magnetron sputtering, a copper foil layer is prepared on the surface of the metal layer through electroplating or chemical copper deposition, and the conductive copper layer is formed on the metal layer and the copper foil layer.

Preferably, the metal layer is a Cu layer, a Ni layer, a Cu/Ni layer or an Ag layer.

On the other hand, the invention also provides a circuit board which is prepared by the preparation method, the copper layer and the insulating layer have good bonding force, and the circuit board has good heat dissipation performance.

Drawings

FIG. 1: FIG. 1(a) shows a schematic structural view of a carrier layer for the present application for the preparation of a conductive copper layer; FIG. 1(b) is a schematic diagram showing the structure of the conductive copper layer etched into the wiring layer shown in FIG. 1(a), which is also a cross-sectional view of the supply roll.

FIG. 2: fig. 2(a) shows a schematic structural diagram of a carrier layer of the present application for preparing a metal layer and a copper foil layer; fig. 2(b) is a schematic structural view of the metal layer and the copper foil layer etched to form the circuit layer shown in fig. 2(a), and is a cross-sectional view of another embodiment of the supply roll.

Fig. 3 shows a schematic flow chart of the processing device for the circuit board of the present application.

Fig. 4 shows an enlarged view at a in fig. 3.

FIG. 5: FIG. 5(a) is a schematic diagram of the structure of the product from the supply roll of FIG. 1 processed by the processing apparatus of FIG. 3, showing the circuit layer embedded in the insulating layer; FIG. 5(b) shows a schematic diagram of a thickened copper layer formed on the wiring layer shown in FIG. 5 (a).

FIG. 6: FIG. 6(a) is a schematic diagram of the structure of the product from the supply roll of FIG. 2 processed by the processing apparatus of FIG. 3, showing the circuit layer embedded in the insulating layer; FIG. 6(b) shows a schematic diagram of a thickened copper layer formed on the wiring layer shown in FIG. 6 (a).

Description of the symbols:

the device comprises a carrier layer 10, a base material layer 11, a stripping layer 13, a conductive copper layer 20, a metal layer 21, a copper foil layer 23, a circuit layer 30, an insulating layer 40, a thickened copper layer 50, a hot pressing device 51, a first unreeling device 52, a second unreeling device 53, a first reeling device 54, a second reeling device 55, a drying device 56, a coating mechanism 57, a hot pressing roller 58, an auxiliary roller 59, a cutting device 60, a feeding roll 70 and heat-conducting glue 80.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of a circuit board, which comprises the following steps:

(2) the carrier layer and the circuit layer form a material supply roll;

The method for producing the circuit board of the present application is further illustrated below with the aid of fig. 1 to 6, as follows:

in the technical solution of the present invention, referring to fig. 1(a), the carrier layer 10 includes a substrate layer 11 and a peeling layer 13 prepared on a surface of the substrate layer 11, a conductive copper layer 20 is prepared on a surface of the peeling layer 13, and the peeling layer 13 is used for removing the carrier layer 10. The substrate layer 11 is selected from a metal substrate or a non-metal substrate, and the provision of the substrate layer 11 can provide support guarantee for the subsequent preparation of the conductive copper layer 20. The metal substrate may be, but is not limited to, copper, aluminum, or stainless steel; the non-metallic substrate may be, but is not limited to, a PET film, a PEN film, a PP film, a PI film, a PC film. Preferably, a non-metallic substrate is provided. In actual preparation, the surface of the substrate layer 11 is pretreated to obtain a suitable surface tension. Preferably, the method of pretreatment may be, but is not limited to, corona or chemical treatment, or the like. Wherein, in order to ensure a certain supporting force, the thickness of the substrate layer 11 is 25 μm-100 μm. For example, the thickness of the substrate layer 11 may be, but is not limited to, 25 μm, 35 μm, 45 μm, 55 μm, 65 μm, 75 μm, 85 μm, 95 μm, 100 μm.

In the technical solution of the present invention, please refer to fig. 1(a) continuously, the peeling layer 13 is prepared on the surface of the substrate layer 11, and the forming manner of the peeling layer 13 is not limited to bonding, printing, injection molding, pressing, etc. In this embodiment, a release layer 13 is bonded to the surface of the base layer 11. The peel ply 13 can peel off so that get rid of the substrate layer 11 with the electrically conductive copper layer 20 (be circuit layer 30 after the etching), and operation peel ply 13 is released type so that get rid of the substrate layer 11, makes substrate layer 11 and circuit layer 30 separation with the help of peel ply 13, and consequently, circuit layer 30 and heat conduction glue solution 80 imbed each other under the hot pressing, and circuit layer 30 imbeds in insulating layer 40 after the shaping, improves the cohesion of circuit layer 30 and insulating layer 40 greatly. Further, the peeling layer 13 may be made of silicon, fluorine, non-silicon, or the like, or may be made of a release material.

In the technical solution of the present invention, please refer to fig. 1(a) continuously, after the peeling layer 13 is prepared, the conductive copper layer 20 is prepared on the surface of the peeling layer 13, and the conductive copper layer 20 may be formed by, but not limited to, vacuum magnetron sputtering, chemical plating, water electroplating, chemical copper deposition, and other technical means. By the above-described means, an extremely thin conductive copper layer 20 can be obtained on the surface of the peeling layer 13, facilitating etching. The thickness of the conductive copper layer 20 is 0.5 μm to 18 μm, for example, the thickness of the conductive copper layer 20 may be, but is not limited to, 0.5 μm, 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 11 μm, 13 μm, 15 μm, 17 μm, 18 μm. Preferably, the thickness of the conductive copper layer 20 is 2 μm to 9 μm.

In a preferred embodiment of the above technical solution, referring to fig. 2(a), the conductive copper layer 20 includes a metal layer 21 and a copper foil layer 23 located on a surface of the metal layer 21. Preparing a metal layer 21 on the surface of the stripping layer 13 by vacuum magnetron sputtering, preparing a copper foil layer 23 on the surface of the metal layer 21 by electroplating or chemical copper deposition, and forming a conductive copper layer 20 on the metal layer 21 and the copper foil layer 23. Firstly, a thin metal layer 21 is formed on the surface of the stripping layer 13 through vacuum magnetron sputtering, and then a copper foil layer 23 is formed on the surface of the metal layer 21 through electroplating or chemical copper deposition, so that the cost is reduced, and the yield and the productivity are improved. Further, the metal layer 21 is a Cu layer, a Ni layer, a Cu/Ni layer, or an Ag layer. Preferably, the metal layer 21 is a Cu/Ni layer, which is beneficial to improve the performance of the circuit board.

In the technical solution of the present invention, referring to fig. 1(b), after the conductive copper layer 20 is prepared, the conductive copper layer 20 is etched to form the circuit layer 30. Since the conductive copper layer 20 has a small thickness, the etching process is easy, a small line width can be obtained, for example, the line width is 2 μm, the line distance is 3 μm, the transmission speed is increased, the amount of the etching solution is small, and the method is environment-friendly and low in cost. Further, referring to fig. 2(b), the conductive copper layer 20 includes a metal layer 21 and a copper foil layer 23, and both the metal layer 21 and the copper foil layer 23 are etched to form a circuit layer 30. Among them, the etching process is a common manner in the art and will not be described herein.

In the technical scheme of the invention, after the conductive copper layer 20 is etched into the circuit layer 30, the carrier layer 10 and the circuit layer 30 form a rolled supply roll 70, and the carrier layer 10 and the circuit layer 30 are prepared and then the supply roll 70 is obtained in a rolling manner for subsequent processes. Because the peeling layer 13 in the carrier layer 10 has a certain adhesion with the conductive copper layer 20, after the conductive copper layer 20 is etched into the circuit layer 30, the circuit layer 30 is not separated from the carrier layer 10 under the condition of no external force, and the circuit layer 30 and the carrier layer 10 are made into a supply roll 70 for standby.

In the technical solution of the present invention, please refer to fig. 3, a hot press device 51, a first unwinding device 52, a second unwinding device 53, a first winding device 54, a second winding device 55, and a drying device 56 are provided. The number of the hot pressing devices 51 is at least 2, and the hot pressing devices are symmetrically arranged. Because a double-sided copper-clad plate needs to be obtained, 2 feeding rolls 70 are provided, the first unwinding device 52 corresponds to 1 of the two feeding rolls, and the second unwinding device 53 corresponds to the other feeding roll. Along the conveying direction K, the first unwinding device 52 and the second unwinding device 53 are sequentially arranged in front and at the back, and the heat-conducting glue solution 80 is sent to the surface of the feeding roll unwound by the first unwinding device 52, for example, in coating, spreading, printing and other modes. In the present embodiment, a coating mechanism 57 is provided and located between the first unwinding device 52 and the drying device 56, and the coating mechanism 57 is configured to coat the heat-conducting glue 80 on the surface of the supply roll 70. And 2 first winding devices 54 are provided to wind the carrier layer 10 removed from the corresponding supply roll 70, i.e., to peel off the carrier layer 10, and a second winding device 55 is provided to wind the product. In this embodiment, the first unwinding device 52 unwinds one of the material supply rolls 70, the second unwinding device 53 unwinds the other material supply roll 70, the coating mechanism 57 sends the heat-conducting glue 80 to the surface of the material supply roll 70 conveyed by the first unwinding device 52, and the heat-conducting glue 80 is dried by the drying device 56 and then matched with the material supply roll 70 conveyed by the second unwinding device 53, so that the two material supply rolls 70 and the heat-conducting glue 80 therebetween jointly enter between the two hot pressing devices 51 to form the insulating layer 40 after hot pressing, the circuit layer 30 is embedded in the insulating layer 40, the carrier layer 10 of the material supply roll 70 is wound by the first winding device 54 to drive the peeling layer 13 to separate from the conductive copper layer 20, and the two conductive copper layers 20 move by the winding tension of the second winding device 55.

In the technical solution of the present invention, referring to fig. 3, along the transportation direction K, a hot press roller 58 is disposed behind the hot press device 51, and the hot press device 51 performs a first hot press forming, and then the hot press roller 58 performs a second hot press forming. Namely, two hot-pressing rollers 58 are used to hot-press the two conductive copper layers 20 and the heat-conducting glue solution located between the two conductive copper layers 20 again. It is understood that after the first thermal compression curing by the two thermal compression devices 51, the second thermal compression curing is performed by the two thermal compression rollers 58 to improve the curing and adhesion properties. It should be noted that, in the technical solution, a plurality of auxiliary rollers 59 are further provided to ensure smooth operation of the winding devices, in this embodiment, two auxiliary rollers 59 are respectively and correspondingly arranged in front of the two first winding devices 54, and the auxiliary roller 59 is arranged on one side of the first unwinding device 52 close to the coating mechanism 57, but not limited thereto, and may be set according to actual operation needs. In order to meet different requirements, a cutting device 60 is arranged before the product is rolled, so that the layered copper-clad plate can be obtained.

In the technical scheme of the invention, the heat-conducting glue solution comprises a glue material, a curing agent, heat-conducting powder and a solvent. Preferably, the sizing material is at least one of epoxy resin, MPI and silica gel, or nitrile rubber and epoxy resin composite rubber. The thermally conductive powder is selected from Al₂O₃At least one of AlN, SiC, BN and graphene. The solvent may be acetone, ethylene glycol, etc., but is not limited thereto.

In the present invention, referring to fig. 5(a), fig. 5(b), fig. 6(a) and fig. 6(b), after obtaining a product in which the circuit layer 30 is embedded in the insulating layer 40, a thickened copper layer 50 is prepared on the surface of the circuit layer 30 where the insulating layer 40 is exposed. Namely, a thicker thickened copper layer 50 is obtained on the surface of the circuit layer 30 to improve the conveying capacity of the circuit board. It will be appreciated that the present application is a double-sided copper layer, and thus, both double-sided wiring layers 30 produce a thickened copper layer 50. In particular, the thickened copper layer 50 can be formed by electrolytic copper plating, electroless copper plating or electroless copper plating. In this embodiment, a layer of copper is plated on the surface of the circuit layer 30 by electroplating to increase the thickness of the circuit layer 30 in the insulating layer 40, and the specific thickness is obtained as required. Because the circuit layer 30 is embedded in the insulating layer 40, the adhesion, the stability and the service life between the circuit layer 30 and the insulating layer 40 are effectively guaranteed.

Compared with the prior art, the preparation method of the circuit board adopts the carrier layer 10 as the carrier to prepare the conductive copper layer 20, can prepare the thin conductive copper layer 20, is convenient to etch and low in cost, can etch the circuit board accurately to obtain the circuit board with narrow line width, and can improve the utilization rate of the circuit board and increase the data transmission effect. The base material layer 11 is peeled by the aid of the peeling layer 13, the carrier layer 10 is wound by the aid of the first winding device 54, a product is wound by the second winding device 55, the heat-conducting glue solution between the two circuit layers 30 is dried by the drying device 56, and then is subjected to hot-pressing curing treatment by the hot-pressing device 51 to form the insulating layer 40, the insulating layer 40 and the circuit layers 30 are embedded into each other, and therefore on one hand, the bonding force between the insulating layer 40 and the circuit layers 30 is improved, and on the other hand, the heat-conducting glue solution endows the circuit board with a good heat-conducting effect. The process avoids the situation that the thin copper is easy to break due to tension, and realizes high yield and high yield of the circuit board.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the present invention, therefore, the present invention is not limited by the appended claims.

Claims

1. A method for manufacturing a circuit board is characterized by comprising the following steps:

(2) the carrier layer and the circuit layer form a material supply roll;

2. The method for producing a wiring board according to claim 1, wherein the base material layer is selected from a metal base material and a non-metal base material.

3. The method of manufacturing a wiring board according to claim 2, wherein the metal substrate is selected from copper, aluminum, or stainless steel.

4. The method of manufacturing a wiring board according to claim 1, wherein the thickness of the conductive copper layer is 0.5 μm to 18 μm.

5. The method for manufacturing a circuit board according to claim 1, wherein the thermally conductive glue comprises a sizing material, a curing agent, thermally conductive powder and a solvent.

6. The method for preparing the circuit board according to claim 5, wherein the rubber compound is at least one selected from epoxy resin, MPI and silica gel, or a nitrile rubber and epoxy resin composite rubber.

7. The method for manufacturing a circuit board according to claim 1, wherein the conductive copper layer is formed on the surface of the release layer by means of vacuum magnetron sputtering, electroless plating, water electroplating or electroless copper plating.

8. The method for preparing the circuit board according to claim 1, wherein a metal layer is prepared on the surface of the carrier layer by vacuum magnetron sputtering and a copper foil layer is prepared on the surface of the metal layer by electroplating or chemical copper deposition, and the metal layer and the copper foil layer form the conductive copper layer.

9. The method of manufacturing a wiring board according to claim 8, wherein the metal layer is a Cu layer, a Ni layer, a Cu/Ni layer, or an Ag layer.

10. A wiring board produced by the production method according to any one of claims 1 to 9.