CN110572939B

CN110572939B - 3D printing circuit board and method thereof

Info

Publication number: CN110572939B
Application number: CN201910766050.3A
Authority: CN
Inventors: 刘诗涛; 李智; 韩雪川; 崔荣
Original assignee: Shennan Circuit Co Ltd
Current assignee: Shennan Circuit Co Ltd
Priority date: 2019-08-19
Filing date: 2019-08-19
Publication date: 2021-06-01
Anticipated expiration: 2039-08-19
Also published as: CN110572939A

Abstract

The application discloses a method for 3D printing a circuit board and the 3D printing circuit board, the method comprises the following steps: printing an insulating layer on a substrate to form a flat layer capable of improving the flatness of a printed circuit; and printing a circuit layer on the surface of one side, opposite to the substrate, of the flat layer. By the method, the flatness of the printed circuit can be improved, and the signal transmission effect of the printed circuit can be further improved.

Description

3D printing circuit board and method thereof

Technical Field

The application relates to the technical field of circuit board processing, in particular to a method for 3D printing of a circuit board and the 3D printing of the circuit board.

Background

Since 3D (english 3Dimensions, that is, three-dimensional) Printed materials are high in price at present and do not need to be Printed as substrate materials, 3D Printed circuits only print copper wires of PCBs (Printed Circuit boards) with chinese names, and only the raw materials are changed from copper-clad substrates to copper-free substrates.

The inventor of the present application found that, in long-term research and development, such a copper-free substrate is mainly composed of polymers, so that although the appearance is flat, the number of voids actually is very large, and if a copper transmission line is directly printed on the copper-free substrate, copper particles easily fall into the polymer voids, and it is known from the skin effect that, as the frequency of a signal is higher, the signal is transmitted close to the surface of a conductor, so that the insertion loss is more likely to increase as the surface is more uneven, and the signal integrity problem occurs.

Disclosure of Invention

The application provides a method for 3D printing a circuit board and the 3D printing circuit board, which can improve the flatness of a printed circuit and further improve the integrity of line signal transmission.

The technical scheme adopted by the application is as follows: there is provided a method of 3D printing a circuit board,

the method comprises the following steps:

printing an insulating layer on a substrate to form a flat layer capable of improving the flatness of a printed circuit;

and printing a circuit layer on the surface of one side, opposite to the substrate, of the flat layer.

Another technical scheme adopted by the application is as follows: provided is a 3D printed circuit board including:

a substrate, an insulating layer, and a circuit layer which are stacked;

the insulating layer is a 3D printing layer and is used for flattening the surface of the substrate so as to improve the flatness of a printed circuit;

the circuit layer is a 3D printing layer and is positioned on the surface, back to the substrate, of the flat layer.

The beneficial effect of this application is: be different from prior art's condition, this application can avoid in the hole of flat layer and base plate at the conductive particle of printing in-process circuit layer china ink through printing the insulating layer as the flat layer on the base plate at first, the formation of flat layer to improve the roughness on the surface of the circuit of printing out, and then improve circuit signal transmission's integrality.

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 description of the embodiments are briefly introduced 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 creative efforts. Wherein:

fig. 1 is a schematic flow chart of a method for 3D printing a circuit board according to an embodiment of the present application;

FIG. 2 is a schematic flow chart of step S101 provided in the embodiment of FIG. 1;

fig. 3 is a schematic flow chart of a method for 3D printing a circuit board according to another embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all 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 application.

Referring to fig. 1, fig. 1 is a flowchart illustrating a method for printing a circuit board in 3D according to an embodiment of the present disclosure. The method comprises the following steps:

s101, printing an insulating layer on a substrate to form a flat layer capable of improving the flatness of a printed circuit.

The substrate in this embodiment is an insulating copper-free substrate.

The X-direction precision of the 3D printing equipment adopted in the step is more than 15 microns, the Y-direction precision of the 3D printing equipment is more than 15 microns, and the precision perpendicular to the XY surface is more than 5 microns.

Referring to fig. 2, fig. 2 is a flowchart of step S101 of the embodiment of fig. 1. Specifically, step S101 includes:

s1011, printing a molten insulating layer on the substrate;

and S1012, primarily solidifying the molten insulating layer.

In some alternative embodiments, the insulating layer ink used for printing the insulating layer comprises the following components in percentage by mass: 90-95% (e.g., 90%, 92%, 94%, 95%) ethyl cyanoacrylate and 5-10% (e.g., 5%, 6%, 8%, 10%) boron impurities.

The primary curing is UV (UV is English abbreviation of Ultraviolet curing) Ultraviolet curing, the temperature used for the primary curing is 85-105 ℃ (such as 85 ℃, 92 ℃, 99 ℃, 105 ℃) and the time is 5-15 (such as 5, 9, 12, 15) minutes.

The primary curing in this embodiment may be understood as meaning incomplete curing, non-drying, partial curing, and the like.

The ethyl cyanoacrylate in the embodiment is a glue with strong adhesive force, the colloid viscosity of the glue is usually 10 +/-5, and the bonding force between the printed circuit layer and the substrate can be enhanced.

A small amount of boron impurities is added to the ethyl cyanoacrylate to increase the surface tension of the formed insulating layer and planarization layer, so as not to cause the printed insulating layer to flow to other positions at the time of printing or at the time of partial curing due to too small tension.

In other alternative embodiments, the insulating layer ink used for printing the insulating layer comprises the following components in percentage by mass: 65% to 75% (e.g., 65%, 70%, 72%, 75%) of a one-component room temperature vulcanized silicone rubber, 3% to 7% (e.g., 3%, 5%, 7%) of methyltriacetoxysilane, 20% to 30% (e.g., 20%, 23%, 30%) of calcium carbonate, 0.5% to 1.2% (e.g., 0.5%, 0.7%, 1%, 1.2%) of a catalyst, and less than 1% of water for adjusting viscosity.

Wherein, the catalyst can be titanate.

Optionally, the insulating layer ink may further include a flame retardant, a heat-resistant additive, and the like. Wherein the flame retardant can be dibromomethane, trichlorobromomethane, dichlorobromomethane, tributyl phosphate, tris (2-ethylhexyl) phosphate, tris (2-chloroethyl) phosphate, etc. The heat-resistant additive may be alkylphenol, butylated toluene, or the like.

The vulcanization reaction of the single-component room temperature vulcanized silicone rubber is to vulcanize the single-component room temperature vulcanized silicone rubber into an elastomer by the action of moisture in the air. The vulcanization reaction proceeds from the surface gradually deeper, the thicker the bond line, the slower the curing. The vulcanization time of the single-component room temperature vulcanized silicone rubber depends on a vulcanization system, temperature, humidity and the thickness of the silicone rubber layer, and the vulcanization process can be accelerated by increasing the temperature and humidity of the environment.

In the embodiment, the primary curing is performed by standing at a constant temperature, and the relative humidity used for the primary curing is 50-60% (e.g., 50%, 55%, 60%), the temperature is 40-65 ℃ (e.g., 40 ℃, 50 ℃, 60 ℃, 65 ℃) and the time is 5-10 (e.g., 5, 7.5, 10) minutes.

The single-component room temperature vulcanized silicone rubber does not absorb or release heat during curing, has small shrinkage rate after curing and good adhesion to materials, and can enhance the binding force between a printed circuit layer and a substrate.

Optionally, in this embodiment, the thickness of the planarization layer is 0.03 μm to 0.1 μm (e.g., 0.03 μm, 0.05 μm, 0.1 μm).

Optionally, in this embodiment, the viscosity of the ink for printing the insulating layer is 50 to 500pa.s (e.g., 50pa.s, 200pa.s, 350pa.s, 500 pa.s).

Due to the existence of printing errors, in order to avoid that the conductive particles in the ink of the circuit layer fall to the substrate when the printed circuit is deviated, the width of the insulating layer is larger than that of the circuit layer.

Optionally, an insulating layer is printed on the substrate along the predetermined circuit, and in order to prevent conductive particles in the ink of the circuit layer from falling onto the substrate when the printed circuit is deviated, the width of the insulating layer is greater than that of the predetermined circuit.

And S102, printing a circuit layer on the surface of the flat layer opposite to the substrate.

Optionally, the circuit layer ink contains conductive particles, and the conductive particles may also be one or more of silver nano-particles, copper nano-particles (copper powder), silver nano-alloy or copper nano-alloy.

Specifically, in this step, the circuit layer ink used for printing the circuit layer includes the following components by mass: 65-75% (e.g., 65%, 70%, 72%, 75%) of copper powder, 7-13% (e.g., 7%, 10%, 13%) of glass powder as a filler, 15-25% (e.g., 15%, 20%, 25%) of an organic solvent, and 3-5% (e.g., 3%, 4%, 5%) of an oxidizing agent.

Alternatively, for example, the organic solvent may be diethylene glycol, ethyl alcohol, terpineol, or the like, and the oxidizing agent may be boron oxide or zinc oxide.

Preferably, the viscosity of the circuit layer ink used for printing the circuit layer is 50 to 100pa.s (for example, 50pa.s, 75pa.s, 100 pa.s). The viscosity of the circuit layer ink can be adjusted by adjusting the proportion of the main components and the filler in the circuit layer ink. Wherein, the main component is copper powder, and the filler is glass powder.

This application is through printing the insulating layer as the planarization on the base plate at first, and the formation of planarization can avoid in the hole that the electrically conductive granule in the printing in-process circuit layer china ink falls into planarization and base plate to improve the roughness on the surface of the circuit that prints, and then improve circuit signal transmission's integrality.

Referring to fig. 3, fig. 3 is a flowchart of a method for 3D printing a circuit board according to another embodiment of the present application. The method for 3D printing the circuit board in the embodiment comprises the following steps:

s201, printing an insulating layer on a substrate to form a flat layer capable of improving the flatness of a printed circuit;

s202, printing a circuit layer on the surface of one side, back to the substrate, of the flat layer;

steps S201 and S202 are the same as in the embodiment of fig. 1, and are not described again here.

And S203, carrying out final curing treatment on the flat layer and the circuit layer to form the circuit board.

The final curing treatment in this step is a constant temperature standing treatment in a closed environment, the temperature required in the treatment process is 40 to 65 ℃ (e.g., 40 ℃, 50 ℃, 65 ℃) and the time is 40 to 60 minutes (e.g., 40, 50, 60).

The treatment requires volatilizing the volatile substances in the ink of the circuit layer. In selecting the temperature for final curing, the temperature for final curing needs to be lower than the material decomposition temperature of the insulating layer ink used for the planarization layer, and if too high, the substances in the planarization layer will decompose.

The thickness of the circuit layer formed in this embodiment may be 3 to 7 μm (3 μm, 5 μm, 6 μm, 7 μm).

The embodiment of the present application further provides a 3D printed circuit board, and the circuit board includes:

a substrate, an insulating layer, and a circuit layer which are stacked;

the circuit layer is a 3D printing layer and is positioned on the surface of the flat layer, which faces away from the substrate.

The substrate in this embodiment is an insulating copper-free substrate.

Optionally, in this embodiment, the thickness of the insulating layer is 0.03 to 0.1 μm (e.g., 0.03 μm, 0.05 μm, 0.07 μm, 0.1 μm).

Optionally, in some embodiments, the insulating layer includes the following components by mass ratio: 90-95% (e.g., 90%, 92%, 94%, 95%) ethyl cyanoacrylate and 5-10% (e.g., 5%, 6%, 8%, 10%) boron impurities.

Optionally, in other embodiments, the insulating layer includes the following components by mass ratio: 65% to 75% (e.g., 65%, 70%, 72%, 75%) of a one-component room temperature vulcanized silicone rubber, 3% to 7% (e.g., 3%, 5%, 7%) of methyltriacetoxysilane, 20% to 30% (e.g., 20%, 23%, 30%) of calcium carbonate, 0.5% to 1.2% (e.g., 0.5%, 0.7%, 1%, 1.2%) of a catalyst.

Optionally, the composition of the circuit layer is the remaining part of the electrical printing ink of the circuit layer after the organic solvent is volatilized.

Optionally, in this embodiment, the thickness of the circuit layer is 3 to 7 μm (3 μm, 5 μm, 6 μm, 7 μm).

As for the manufacturing method of the 3D printed circuit board in the embodiment of the present application, the method described above may be referred to.

In the embodiment of the application, the cavity contained in the flat layer printed by ethyl cyanoacrylate or the single-component room temperature vulcanized silicone rubber is smaller than the size of the conductive particles in the conductive printing ink, when the ink of the circuit layer is printed, the conductive particles in the ink of the circuit layer cannot fall into the cavity in the flat layer, so that the flatness of the printed circuit is improved, the circuit in the application has better flatness after curing treatment, and the smoother the surface of the circuit is according to the skin effect, the higher the signal transmission effect is, so the circuit in the embodiment of the application has higher circuit signal transmission effect; meanwhile, the copper foil circuit on the PCB manufactured by the traditional etching technology uses IPC peel strength test of about 0.3N/m, the copper foil circuit layer on the PCB manufactured by the common 3D printing circuit technology uses IPC peel strength test of about 0.5N/m, and the copper foil circuit layer in the embodiment of the application uses IPC peel strength test of about 2N/m, so that the circuit layer and the substrate have higher bonding force.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims

1. A method of 3D printing a circuit board, the method comprising the steps of:

printing a circuit layer on the surface of one side, opposite to the substrate, of the flat layer, wherein the width of the insulating layer is larger than that of a circuit of the circuit layer;

the insulating layer ink adopted for printing the insulating layer comprises the following components in percentage by mass: 90-95% of ethyl cyanoacrylate and 5-10% of boron impurities.

2. The method of 3D printing a circuit board according to claim 1,

the printing of the insulating layer on the substrate includes:

printing a molten insulating layer on the substrate;

primarily solidifying the molten insulating layer;

the method comprises the following steps after a circuit layer is printed on the surface of the flat layer on the side opposite to the substrate:

and carrying out final curing treatment on the flat layer and the circuit layer to form the circuit board.

3. The method for 3D printing the circuit board according to claim 2, wherein the preliminary curing is UV curing, and the temperature for the preliminary curing is 85-105 ℃ and the time is 5-15 minutes.

4. The method for 3D printing of the circuit board according to claim 2, wherein the insulating layer ink used for printing the insulating layer comprises the following components by mass: 65-75% of single-component room-temperature vulcanized silicone rubber, 3-7% of methyltriacetoxysilane, 20-30% of calcium carbonate, 0.5-1.2% of catalyst and less than 1% of water.

5. The method for 3D printing the circuit board according to claim 4, wherein the preliminary curing is performed by standing at a constant temperature, the relative humidity of the preliminary curing is 50-60%, the temperature is 40-65 ℃, and the time is 5-10 minutes.

6. The method of 3D printing circuit board according to claim 1, wherein the thickness of the flat layer is 0.03-0.1 μm.

7. The method of 3D printing a circuit board according to claim 1, wherein the circuit layer ink used for printing the circuit layer comprises the following components by mass: 65-75% of copper powder, 7-13% of glass powder as a filler, 15-25% of an organic solvent and 3-5% of an oxidant.

8. The method of claim 1, wherein the viscosity of the ink for printing the insulating layer is 50 to 500pa.s, and the viscosity of the ink for printing the circuit layer is 50 to 100 pa.s.

9. The method of 3D printing circuit board according to claim 1, characterized in that the method uses a 3D printing device with X-direction precision greater than 15 μm, a 3D printing device with Y-direction precision greater than 15 μm, and a precision perpendicular to the XY plane greater than 5 μm.

10. The method for 3D printing the circuit board according to claim 2, wherein the curing treatment in the step of finally curing the flat layer and the circuit layer is a constant temperature standing treatment in a closed environment, and the temperature required in the treatment process is 40-65 ℃ and the time is 40-60 minutes.

11. A3D printed circuit board, comprising:

a substrate, an insulating layer, and a circuit layer which are stacked;

the circuit layer is a 3D printing layer and is positioned on the surface of the flat layer, which faces away from the substrate, and the width of the insulating layer is greater than that of the circuit; wherein the insulating layer comprises the following components in percentage by mass: 90-95% of ethyl cyanoacrylate and 5-10% of boron impurities.

12. The 3D printed circuit board according to claim 11, wherein the insulating layer comprises either the following components in mass ratio: 65-75% of single-component room temperature vulcanized silicone rubber, 3-7% of methyl triacetoxy silane, 20-30% of calcium carbonate and 0.5-1.2% of catalyst.

13. The 3D printed circuit board according to claim 11, wherein the thickness of the insulating layer is 0.03 to 0.1 μm.

14. The 3D printed circuit board according to claim 11, wherein the thickness of the circuit layer is 3-7 μm.