CN113133208A

CN113133208A - Circuit processing method based on laser etching

Info

Publication number: CN113133208A
Application number: CN202110395467.0A
Authority: CN
Inventors: 杨林; 杨承杰
Original assignee: Shenzhen Sanwei Circuit Technology Co ltd
Current assignee: Shenzhen Sanwei Circuit Technology Co ltd
Priority date: 2021-04-13
Filing date: 2021-04-13
Publication date: 2021-07-16

Abstract

The invention relates to a line processing method based on laser etching, which comprises the following steps: s1, preparing a substrate serving as a circuit board, and etching a groove body on the processed surface of the cleaned substrate in a laser etching mode, wherein the groove body is a blind groove, and the thickness of the blind groove is 30Z; s2, cleaning the substrate with the blind groove, coating copper paste in the blind groove after the cleaning, and post-treating; and S3, removing the copper paste protruding from the boundary of the processing surface of the substrate and the blind groove in the post-processing structure in the S2 by using a ceramic brush to obtain the structure with the copper wire. The method solves the problem of poor PP glue filling caused by over-thick copper, and the surface of the produced circuit board has good flatness. Compared with the traditional liquid medicine etching line, the invention only uses a small amount of liquid medicine in the processing process, thereby greatly reducing the pollution of the liquid medicine and the waste gas to the environment.

Description

Circuit processing method based on laser etching

Technical Field

The invention relates to a PCB (printed circuit board) circuit processing technology, in particular to a circuit processing method based on laser etching.

Background

With the rapid development of the printed circuit board manufacturing towards the direction of multilayering, miniaturization, functionalization and integration, a large number of micro-hole and fine line width and line distance circuits are designed in the printed circuit board, the processing technology requirements for the printed circuit board are higher and higher, and the traditional circuit processing method generally adopts the methods of liquid medicine etching such as acid etching, alkaline etching and the like. The processing methods have multiple working procedures, large errors are easily caused to the high-precision circuit board, a large amount of conductive materials are wasted in the etching process, and the used liquid medicine causes great pollution to the environment. Especially, when the line width and the line distance of the line are small to a certain degree, the accuracy and the uniformity of the line cannot be ensured due to the lateral corrosion behavior in the etching process, and a micro line with higher accuracy cannot be manufactured.

The traditional circuit is processed by adopting a liquid medicine etching method, and the flow of the etching circuit is as follows: pretreatment → film pressing → exposure → development → etching → film stripping, which uses a large amount of liquid medicine and generates waste gas polluting the environment in the manufacturing process, and the environment is seriously polluted by improper treatment.

For the circuit with small line width and line distance, the analysis capability of a dry film is limited during processing, the film can be thrown away during film pressing, so that an open circuit condition occurs after etching, the bonding force between the circuit and a substrate is poor when the circuit is too thin, the reliability is reduced, and the open circuit can be caused when the post-processing procedure is subjected to processes such as brushing and grinding. For the circuit with high copper thickness, the PP glue filling is poor due to the excessive thickness of the circuit during pressing, and the cavity in the frame line in the figure 1 is formed, so that the problem of board explosion occurs during pressing, and the pressed board surface is uneven and uneven, and the structure in the frame line in the figure 2 causes poor follow-up SMT pasting.

Disclosure of Invention

Technical problem to be solved

In view of the above-mentioned drawbacks and deficiencies of the prior art, the present invention provides a method for processing a circuit by laser etching.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

in a first aspect, an embodiment of the present invention provides a line processing method based on laser etching, including:

s1, preparing a substrate serving as a circuit board, and etching a groove body on the processed surface of the cleaned substrate in a laser etching mode, wherein the groove body is a blind groove, and the thickness of the blind groove is 30Z;

s2, cleaning the substrate with the blind groove, coating copper paste in the blind groove after the cleaning, and post-treating;

and S3, removing the copper paste protruding from the boundary of the processing surface of the substrate and the blind groove in the post-processing structure in the S2 by using a ceramic brush to obtain the structure with the copper wire.

Optionally, the S1 includes:

processing by adopting laser according to the etching information of the preset line width and the 30Z thickness;

specifically, a picosecond laser is used, and the cutting is performed 3-10 times at a power of 10W and a speed of 200 MJ.

Optionally, the S1 includes:

at a preset line width of 50um and a thickness of 30Z, four picosecond lasers with beam arrangement were used and cut 6 times at a power of 10W and a speed of 200 MJ.

Optionally, the S2 includes:

s31, cleaning the liquid in the blind groove by adopting plasma and ultrasonic liquid;

s32, after the cleaning and drying treatment, forming a copper paste layer in the clean and dried blind groove by adopting a vacuum printing process;

and S33, curing the copper paste layer by adopting a high-temperature baking mode.

Optionally, the S3 includes:

and removing the copper slurry protruding from the junction of the blind groove and the substrate by adopting a plate grinding line corresponding to the 500-mesh 800-mesh roller.

Optionally, the S1 includes:

and after preparing a substrate serving as a circuit board, cleaning the processing surface of the substrate, and etching a groove body on the cleaned processing surface of the substrate by adopting a laser etching mode aiming at the cleaned processing surface of the substrate.

Optionally, the S33 includes:

keeping the temperature at 100 ℃ for 5-10 minutes, and then baking at 200-300 ℃ for 3-8 minutes to solidify the copper paste layer.

In a second aspect, the present invention further provides a circuit processing board, which is characterized in that a structure with a copper wire corresponding to the circuit processing board is prepared by using any one of the methods described in the first aspect.

(III) advantageous effects

The laser etching mode of the invention carries out circuit processing on the processing surface of the substrate, thereby effectively manufacturing circuits with small line width and high copper thickness and solving the problem of limited exposure processing capability.

The copper circuit processed in the invention is embedded in the substrate and has good bonding force with the substrate, so that the circuit is hardly influenced by post-processing, and the copper circuit has excellent reliability. The invention solves the problem of poor PP glue filling caused by over-thick copper, and the surface of the produced circuit board has good smoothness. Compared with the traditional liquid medicine etching line, the invention only uses a small amount of liquid medicine in the processing process, thereby greatly reducing the pollution of the liquid medicine and the waste gas to the environment.

Drawings

FIG. 1 is a schematic diagram of the prior art with poor PP filling;

FIG. 2 is a schematic view of a prior art panel having an uneven surface;

FIG. 3 is a schematic diagram of laser grooving in an embodiment of the present invention;

FIG. 4 is a schematic illustration of laser scribing the laser scribe of FIG. 3 in accordance with an embodiment of the present invention;

FIG. 5 is a schematic diagram of a copper-carrying copper wire structure corresponding to a circuit board according to an embodiment of the present invention;

fig. 6 is a schematic flowchart of a method for processing a circuit based on laser etching according to an embodiment of the present invention.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

In order to better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Example one

Referring to fig. 1 and 2 of the prior art, fig. 1 and 2 show that the PP paste is poorly filled in the high copper thickness circuit in the prior art, resulting in whitening and the problem of unevenness of the board surface.

In an embodiment of the present invention, a circuit processing method based on laser etching is provided, as shown in fig. 6, the method may include:

step a1 is to prepare a substrate as a wiring board and to clean the processed surface of the substrate.

It should be noted that in this embodiment, the substrate may be FR4, and the thickness of the substrate needs to be customized or matched according to the thickness of the product. In this embodiment, either surface of the FR4 substrate can be used as a processing surface.

In practical application, the processing surface of the substrate does not need to be cleaned, and in order to ensure the precision of the substrate preparation, the processing surface of the substrate can be cleaned in the embodiment.

And A2, etching a groove body on the processed surface of the cleaned substrate by adopting a laser etching mode, wherein the groove body is a blind groove, and the thickness of the blind groove is 30Z.

In this embodiment, the shape of the groove body can be a straight line and a curve, and the cross section of any blind groove can be a rectangle.

For example, in the present embodiment, laser is used for processing according to the etching information of the preset line width and 30Z thickness. For example, a picosecond laser may be used, cutting 3-10 times, preferably 6 times, at a power of 10W and an energy of 200 MJ.

For example, since the picosecond laser has a width of one beam of 12.5um, at a predetermined line width of 50um, 30Z thick, a picosecond laser with four beam arrangements was used, and cut 6 times at a power of 10W and a speed of 200 MJ.

Step A3, for the structure of step a2, a cleaning process is performed on the substrate having the blind groove, and after the cleaning process, copper paste is applied to the blind groove and a post-process is performed.

This step may include, for example, the following substeps:

a31, cleaning a blind groove by adopting plasma and ultrasonic liquid;

in this example, ultrasonic liquid ultrasonic cleaning may be used for 45 minutes and plasma cleaning for 30 minutes.

And A32, after the cleaning and drying treatment, forming a copper paste layer in the cleaning and drying blind groove by adopting a vacuum printing process.

That is, the liquid copper is printed in the blind via vacuum printing.

And A33, curing the copper paste layer by adopting a high-temperature baking mode.

For example, the copper paste layer is cured by keeping the temperature at 100 ℃ for 5 to 10 minutes and then baking the copper paste layer at 200 ℃ to 300 ℃ for 3 to 8 minutes, for example, baking the copper paste layer at 150 ℃ for 6 minutes.

Specifically, the copper paste is filled in the blind groove by adopting a vacuum printing mode, so that the board surface of the substrate, namely the processing surface, does not have the copper paste, and the copper paste can be solidified by adopting a high-temperature baking mode after printing.

And step A4, removing the copper paste protruding from the junction of the processing surface of the substrate and the blind groove in the post-processed structure in the step A3 by ceramic brushing to obtain the structure with the copper wire.

In this embodiment, after the copper paste is printed and cured, the copper paste may protrude from the boundary between the blind slot and the substrate, and the ceramic brushing is performed to polish the protruding copper paste to obtain a flat substrate surface, and a special polishing line is typically used in 500-mesh 800-mesh roller ceramic brushing.

In this embodiment, a method for re-processing a circuit by grooving a copper-free substrate with laser light emitted from a picosecond laser may be used to manufacture a circuit with a small line width (e.g., 20um minimum) and a high copper thickness, and the problem of limited exposure process capability may be solved by controlling the line width and the copper thickness with laser. The processed circuit is embedded in the substrate and has good bonding force with the substrate, so that the circuit is hardly influenced by post-processing, and the circuit has excellent reliability. The invention solves the problem of poor PP glue filling caused by over-thick copper, and the surface of the produced circuit board has good smoothness. Compared with the traditional liquid medicine etching line, the invention only uses a small amount of liquid medicine in the processing process, thereby greatly reducing the pollution of the liquid medicine and the waste gas to the environment.

Example two

The embodiment of the invention provides a line processing method based on laser etching, which can be used for processing lines with small line width and high copper thickness. In the embodiment, taking the fabrication of a 3OZ copper thick circuit as an example for explanation, the method of the embodiment may include:

101. laser is used for etching a blind groove with the thickness of 3OZ and the width of the design line width on the surface of the copper-free substrate, as shown in figures 3 and 4.

The line width in this embodiment can be 20um to 100um, and the cross sectional shape of the groove to be referred to in this embodiment is a rectangle. The bare body in this embodiment etches substantially T-shaped or L-shaped slots.

And (3) adjusting the size of a laser spot by 20um by using picosecond laser, and after the blind groove size and the depth of the plate edge trial cutting blind groove slice are confirmed to meet the use requirement, laser is used for producing the blind groove in the plate according to a pre-designed pattern.

102. And cleaning the structure of the etching blind slot.

In this embodiment, the inside of the tank is cleaned by two modes, namely plasma (plasma) and ultrasonic cleaning, mainly.

103. And filling copper slurry in the blind groove for processing the substrate.

For example, a copper paste is applied in the blind grooves by vacuum printing/screen printing.

104. And (4) post-treatment baking to firmly combine the copper paste with the substrate.

For example, baking at a temperature of 150 ℃ for 60 minutes, or baking at a temperature of 130 ℃ for 90 minutes.

105. Excess copper paste on the surface of the substrate is removed by ceramic brushing to obtain a board with circuits, as shown in fig. 5.

In this embodiment, for the copper paste protruding from the boundary between the processing surface of the substrate and the blind via in the post-processing structure in 104, a structure with copper paste is obtained, which is used to polish the notch.

The method solves the problem of poor PP glue filling caused by over-thick copper, and the surface of the produced circuit board has good flatness. Compared with the traditional liquid medicine etching line, the invention only uses a small amount of liquid medicine in the processing process, thereby greatly reducing the pollution of the liquid medicine and the waste gas to the environment.

According to another aspect of the present invention, there is also provided a circuit processing board, wherein the circuit processing board can be prepared by any one of the above-mentioned methods of the first aspect (as shown in fig. 5) during the initial preparation stage.

It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the terms first, second, third and the like are for convenience only and do not denote any order. These words are to be understood as part of the name of the component.

Furthermore, it should be noted that in the description of the present specification, the description of the term "one embodiment", "some embodiments", "examples", "specific examples" or "some examples", etc., means that a specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, the claims should be construed to include preferred embodiments and all changes and modifications that fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include such modifications and variations.

Claims

1. A circuit processing method based on laser etching is characterized by comprising the following steps:

2. The method according to claim 1, wherein the S1 includes:

3. The method according to claim 1, wherein the S1 includes:

4. The method according to any one of claims 1 to 3, wherein the S2 includes:

5. The method according to claim 1, wherein the S3 includes:

6. The method according to claim 1, wherein the S1 includes:

7. The method according to claim 4, wherein the S33 includes:

8. A wiring board characterized in that a structure with copper wires corresponding to the wiring board is prepared by the method as claimed in any one of claims 1 to 7.