CN113194617A

CN113194617A - PCB negative film production process

Info

Publication number: CN113194617A
Application number: CN202110310815.XA
Authority: CN
Inventors: 万德武; 谢宇光; 张勇
Original assignee: Jiangmen Benlida Printed Circuit Co ltd
Current assignee: Jiangmen Benlida Printed Circuit Co ltd
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2021-07-30

Abstract

The invention discloses a production process of a PCB negative film, which is characterized in that a hole is drilled by a perforating machine after a PCB is fixed; copper deposition: depositing a thin layer of chemical copper on the drilled non-conductive PCB by a chemical method; DVCP thickening: the DVCP makes metal or alloy deposit on the surface of the workpiece by using current to form a uniform and compact metal layer with good bonding force; plugging a hole: using the PCB for the conducted VIA hole, printing by a machine, and plugging ink or resin into the hole; grinding a plate: polishing the rough surface of the PCB board to be smooth; dry film; the invention aims to provide a production process of a PCB negative film, which has the advantages that the production capacity of the negative film is improved; the proportion of negative film production is improved from 10% to 40%, the capacity matching is more reasonable, the capacity exertion maximization and the tin use and recovery processing cost are reduced by 30%, the energy is saved, and the waste is reduced.

Description

PCB negative film production process

Technical Field

The invention relates to the technical field of electronic elements, in particular to a production process of a PCB negative film.

Background

The PCB, which is called a printed circuit board in chinese, is an important electronic component, a support of the electronic component, a carrier for electrical connection of the electronic component, and is called "printing" because it is manufactured by electronic printing.

At present, with the development of the electronic industry, the PCB is widely used as an important electronic component. The negative plate is an important means for manufacturing the PCB, the production flow of the PCB comprises a positive plate flow and a negative plate flow in the process of electroplating patterns, tin plating and stripping are required in the production process of the positive plate flow, a large amount of tin is used, tin treatment cost is generated, the production cost and subsequent treatment cost are very high, and secondary pollution is easily caused. The negative film process can solve the problem of tin plating treatment, save the wastewater treatment cost and shorten the production period, but due to the limitation of the processing capacity, when the designed line width and line distance of the PCB and the width of a welding ring are smaller, the negative film process is not suitable for the process, and the proportion occupied in the PCB production is low, so the PCB negative film production process is provided to solve the problem.

Disclosure of Invention

The invention aims to provide a production process of a PCB negative film, which has the advantages that the production capacity of the negative film is improved; the proportion of negative film production is improved from 10% to 40%, the capacity matching is more reasonable, the capacity exertion maximization and the tin use and recovery processing cost are reduced by 30%, the energy is saved, and the waste is reduced.

In order to achieve the purpose, the invention provides the following technical scheme: a production process of a PCB negative film comprises the following steps: the method comprises the following steps:

step 1: drilling: fixing the PCB and then drilling by using a perforating machine;

step 2: copper deposition: depositing a thin layer of chemical copper on the drilled non-conductive PCB by a chemical method;

and step 3: DVCP thickening: the DVCP makes metal or alloy deposit on the surface of the workpiece by using current to form a uniform and compact metal layer with good bonding force;

and 4, step 4: plugging a hole: using the PCB for the conducted VIA hole, printing by a machine, and plugging ink or resin into the hole;

and 5: grinding a plate: polishing the rough surface of the PCB board to be smooth;

step 6: dry film: utilizing the photosensitive phase-resolving function of the dry film to carry out illumination polymerization reaction on the required circuit pattern to leave the required circuit pattern, and removing redundant copper through electroplating and etching to leave a required copper surface and a circuit;

and 7: acid etching (etching → stripping): soaking the PCB in an acidic etching solvent for cleaning, and removing the oxide film at the hollow part; etching the unprotected non-conductor part of the circuit board with the pattern away from the copper;

and 8: AOI: the processed PCB is used as a sample plate and is compared with a processed plate, and whether the plate body is qualified or not is detected;

and step 9: resistance welding: pre-drying the printing ink, then carrying out exposure treatment, and operating by using a silk-screen solder resist;

step 10: and (3) writing: inputting required characters according to computer software.

Preferably, in step 2, a layer of 0.3um-0.5um copper is deposited on the hole wall by using the chemical reaction principle, so that the originally insulated hole wall has conductivity, and subsequent plate surface electroplating and pattern electroplating can be carried out smoothly.

Preferably, in step 3, the DVCP thickening is to plate the copper plating layer to a desired thickness in the range of 20-25 um.

Preferably, in the step 4, the copper in the hole is protected from contacting with the outside and is not bitten by the liquid medicine, and meanwhile, the high temperature and high humidity resistance of the PCB is increased, the service life is prolonged, and the performance of the PCB is improved.

Preferably, in step 5, some oxide layers, oil stains and the like on the surface of the PCB are removed by polishing, so as to prevent the solder mask and the circuit film from being directly separated from the surface of the PCB to form isolation, and the film can be peeled off and peeled off when the solder mask and the circuit film are processed in a later process.

Preferably, in step 6, the dry film has high requirements on warm and humid conditions. The temperature is generally required to be 20 +/-1 ℃ and the humidity is required to be 60 +/-5%. To prevent deformation of the film.

Preferably, in the step 7, 3-5% sodium hydroxide solution is used for membrane removal, the temperature is 50-60 ℃, and the membrane removal mode can be groove-type soaking or machine spraying.

Preferably, in step 8, AOI chinese is automatically detected optically, and by using image comparison, during programming, a standard image of all points is prepared by a good plate and stored in a machine table for making a template, and then the machine table compares the template image with the placed PCB image for detection.

Preferably, said in step 9, on the solder resist material, it must be applied by a liquid wet process or a dry film stack. The dry film solder resist material is supplied at a thickness of 0.07-0.1 mm (0.03-0.04).

Preferably, in step 9, the main purpose of the silk-screen solder resist is to avoid "bridging" of two wires caused by disordered flow of solder during the electrical mounting process, so as to ensure the quality of the electrical mounting.

Compared with the prior art, the invention has the beneficial effects that: according to the production process of the PCB negative film, the plug holes, the DVCP thickening and the dry film are arranged, so that the problems that the production capacity of the PCB negative film is reduced, the use cost and the recovery processing cost of tin are high, and resources are wasted are solved, and the production process of the PCB negative film has the advantage that the production capacity of the negative film is improved; the proportion of negative film production is improved from 10% to 40%, the capacity matching is more reasonable, the capacity is maximized, the tin use and recovery processing cost is reduced by 30%, and the advantages of energy conservation and waste reduction are achieved.

Detailed Description

The present invention will now be described in more detail by way of examples, which are given by way of illustration only and are not intended to limit the scope of the present invention in any way.

The invention provides a technical scheme that: a production process of a PCB negative film comprises the following steps:

and 7: acid etching (etching → stripping): soaking the PCB in an acidic etching solvent for cleaning, and removing the oxide film at the hollow part; etching the unprotected non-conductor portion of the patterned circuit board away from the copper

The first embodiment is as follows:

fixing the PCB and then drilling by using a perforating machine; copper deposition: depositing a thin layer of chemical copper on the drilled non-conductive PCB by a chemical method; DVCP thickening: the DVCP makes metal or alloy deposit on the surface of the workpiece by using current to form a uniform and compact metal layer with good bonding force; plugging a hole: using the PCB for the conducted VIA hole, printing by a machine, and plugging ink or resin into the hole; grinding a plate: polishing the rough surface of the PCB board to be smooth; dry film: utilizing the photosensitive phase-resolving function of the dry film to carry out illumination polymerization reaction on the required circuit pattern to leave the required circuit pattern, and removing redundant copper through electroplating and etching to leave a required copper surface and a circuit; acid etching (etching → stripping): soaking the PCB in an acidic etching solvent for cleaning, and removing the oxide film at the hollow part; etching the unprotected non-conductor part of the circuit board with the pattern away from the copper; AOI: the processed PCB is used as a sample plate and is compared with a processed plate, and whether the plate body is qualified or not is detected; resistance welding: pre-drying the printing ink, then carrying out exposure treatment, and operating by using a silk-screen solder resist; and (3) writing: inputting required characters according to computer software.

Example two:

in the first embodiment, the following steps are added:

in step 2, a layer of 0.3-0.5 um copper is deposited on the hole wall by utilizing the chemical reaction principle, so that the originally insulated hole wall has conductivity, and subsequent plate surface electroplating and pattern electroplating can be carried out smoothly.

Example three:

in the second embodiment, the following steps are added:

in step 3, DVCP thickening is to plate the copper plating layer to a desired thickness range of 20-25 um.

Example four:

in the third embodiment, the following steps are added:

in the step 4, the copper in the protective hole is prevented from contacting the outside and not bitten by the liquid medicine, and meanwhile, the high-temperature and high-humidity resistance of the PCB is improved, the service life is prolonged, and the performance of the PCB is improved.

Example five:

in the fourth example, the following steps were added:

in step 5, the surface of the PCB is polished to remove oxide layers, oil stains and the like, so that the solder mask and the circuit film are prevented from being directly separated from the surface of the PCB to form isolation, and the film at the position processed by the post-processing procedure can be peeled off and stripped.

Example six:

in the fifth example, the following steps were added:

in step 6, the dry film has a high requirement for the temperature and humidity conditions. The temperature is generally required to be 20 +/-1 ℃ and the humidity is required to be 60 +/-5%. To prevent deformation of the film.

Example seven:

in example six, the following steps were added:

in the step 7, 3-5% sodium hydroxide solution is used for membrane removal, the temperature is 50-60 ℃, and the membrane removal mode can be groove type soaking or machine spraying.

Example eight:

in example seven, the following steps were added:

in step 8, AOI Chinese is automatic optical detection, picture comparison is utilized, standard pictures of all points are made by a good board during programming and stored in a machine table to be a template, and then the machine table compares and detects the template picture with the placed PCB picture.

Example nine:

in example eight, the following steps were added:

in step 9, on the solder resist material, it must be applied by a liquid wet process or a dry film stack. The dry film solder resist material is supplied at a thickness of 0.07-0.1 mm (0.03-0.04); the main purpose of the silk-screen solder resist is to avoid the 'bridging' of two wires caused by the disordered flow of solder in the process of electric installation, and ensure the quality of the electric installation.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A production process of a PCB negative film is characterized by comprising the following steps: the method comprises the following steps:

2. The process of claim 1, wherein the process comprises the following steps: in step 2, a layer of 0.3-0.5 um copper is deposited on the hole wall by utilizing the chemical reaction principle, so that the originally insulated hole wall has conductivity, and subsequent plate surface electroplating and pattern electroplating can be carried out smoothly.

3. The process of claim 1, wherein the process comprises the following steps: in step 3, DVCP thickening is to plate the copper plating layer to a desired thickness range of 20-25 um.

4. The process of claim 1, wherein the process comprises the following steps: in the step 4, the copper in the protective hole is prevented from contacting the outside and not bitten by the liquid medicine, and meanwhile, the high-temperature and high-humidity resistance of the PCB is improved, the service life is prolonged, and the performance of the PCB is improved.

5. The process of claim 1, wherein the process comprises the following steps: in the step 5, the surface of the PCB is polished to remove oxide layers, oil stains and the like, so that the solder mask and the circuit film are prevented from being directly separated from the surface of the PCB to form isolation, and the film at the position processed by the subsequent process can be peeled off and stripped.

6. The process of claim 1, wherein the process comprises the following steps: in the step 6, the dry film has higher requirements on temperature and humidity conditions. The temperature is generally required to be 20 +/-1 ℃ and the humidity is required to be 60 +/-5%. To prevent deformation of the film.

7. The process of claim 1, wherein the process comprises the following steps: in the step 7, 3-5% sodium hydroxide solution is used for membrane removal, the temperature is 50-60 ℃, and the membrane removal mode can be groove type soaking or machine spraying.

8. The process of claim 1, wherein the process comprises the following steps: in step 8, AOI chinese is automatic optical inspection, using picture contrast, during programming, a good board is used to make standard pictures of all points and store them in a machine table for making a template, and then the machine table uses the template picture to compare and inspect the put-in PCB picture.

9. The process of claim 1, wherein the process comprises the following steps: said in step 9, the solder resist material must be applied by a liquid wet process or a dry film stack. The dry film solder resist material is supplied at a thickness of 0.07-0.1 mm (0.03-0.04).

10. The process of claim 1, wherein the process comprises the following steps: in step 9, the main purpose of the screen printing of the solder resist is to avoid "bridging" between two wires due to disordered flow of solder during the electrical mounting process, so as to ensure the quality of the electrical mounting.