阅读说明：本技术 Pcb板电镀硬金渗金的返工方法 (Reworking method for hard gold infiltration electroplating of PCB (printed circuit board) ) 是由 刘勇 王金灵 关俊轩 于 2021-06-22 设计创作，主要内容包括：本发明公开了一种PCB板电镀硬金渗金的返工方法,加工所需尺寸的PCB内层板料,经过贴膜、曝光、蚀刻、褪膜流程后,在PCB内层板料上制作所需的线路图形,将热熔塑胶与内层铜面、铜箔进行粘合、固化；进行贴膜、曝光、显影,电镀硬金,褪膜,检验待蚀刻部位是否出现渗金,使用氮片申请菲林,将渗金部分设定为菲林开窗部分,将不渗金部分设定为菲林不开窗部分；将PCB板板面和孔内印上所需的防焊层并进行绿油处理,绿油之后进行显影处理；将金刚砂喷到菲林开窗部分使渗金部位的金去除。采用检测与连续处理的方式,进行电镀渗金的修复,解决了线路板报废率高的问题,节约成本,提高经济效益。(The invention discloses a rework method for hard gold plating and gold infiltration of a PCB (printed circuit board). A PCB inner layer plate material with required size is processed, after the processes of film pasting, exposure, etching and film removing, a required circuit pattern is manufactured on the PCB inner layer plate material, and hot-melt plastic is bonded and solidified with an inner layer copper surface and a copper foil; carrying out film pasting, exposure and development, electroplating hard gold, stripping a film, checking whether a part to be etched has gold penetration or not, applying for a film by using a nitrogen sheet, setting a gold penetration part as a film windowing part, and setting a non-gold penetration part as a film non-windowing part; printing a required solder mask layer on the surface and in the hole of the PCB, performing green oil treatment, and performing development treatment after the green oil treatment; spraying the diamond sand to the film windowing part to remove the gold at the gold-infiltrated part. The method adopts a detection and continuous treatment mode to repair the electroplated gold-infiltrated part, solves the problem of high rejection rate of the circuit board, saves the cost and improves the economic benefit.)

1. A rework method for hard gold infiltration electroplating of a PCB is characterized by comprising the following steps:

prefabricating and processing steps: processing a PCB inner layer plate material with required size, manufacturing a required circuit pattern on the PCB inner layer plate material after the processes of film pasting, exposure, etching and film removing, and bonding and curing the hot-melt plastic with an inner layer copper surface and a copper foil;

finishing and processing steps: removing the glue flowing and curing part at the plate edge in the pressing process to enable the plate edge to be neat and smooth, punching and realizing subsequent interlayer signal interconnection, and depositing copper and plating copper on the hole and the plate surface;

a primary outer layer processing step: pasting, exposing and developing to expose the required pattern on the PCB, and thickening the copper, nickel and gold in the hole and on the surface of the PCB to the required degree;

secondary outer layer processing: carrying out secondary film pasting, exposure and development to expose the required pattern on the PCB;

electroplating hard gold: electroplating the hard gold pattern area with the thickness of the hard gold required by the customer by using a chemical method;

and (3) film stripping: removing dry films on the primary and secondary outer layer processing pastes of the board surface to expose the part to be etched;

electroplating detection: checking whether the part to be etched has gold penetration or not, if so, executing the next step;

abnormal plate processing step the abnormal plate processing step: applying for a film by using a nitrogen sheet, setting a gold-infiltrated part as a film windowing part, and setting a non-gold-infiltrated part as a film non-windowing part; printing a required solder mask layer on the surface and in the hole of the PCB, performing green oil and exposure treatment, and performing development treatment after exposure;

sand blasting step: spraying the diamond sand to the film windowing part to remove the gold at the gold-infiltrated part.

2. The rework method of electroplating hard gold infiltration for PCB as recited in claim 1, wherein after the secondary outer layer processing step and before the hard gold electroplating step, there is provided an outer layer detection step: checking whether a dry film adhered to the outer layer in one-time processing is loosened, if so, removing the film of the abnormal PCB, applying for a film by using a nitrogen sheet, setting a hard gold graph part of the PCB as a film windowing part, setting a non-hard gold graph part as a film non-windowing part, printing a solder mask layer required by a customer on the surface and in the hole of the PCB, developing, and electroplating hard gold again to the required thickness; if not, the step of electroplating hard gold is executed.

3. The rework method of plating hard gold infiltration for PCB board as claimed in claim 2, characterized in that in the prefabrication processing step: and (3) bonding and curing the hot-melt plastic PP with the inner copper surface and the copper foil.

4. The rework method of electroplating hard gold infiltration on PCB board as recited in claim 1, characterized in that: in the finishing step, after punching, impurities on the surface of the plate are removed, and the copper surface is roughened.

5. The rework method of electroplating hard gold infiltration on PCB board as recited in claim 1, characterized in that: also comprises a green oil fading step: and removing the green oil on the surface of the plate by using NaOH solution.

6. The rework method of electroplating hard gold infiltration on PCB board as recited in claim 5, characterized in that: further comprises a film removing and etching step: and removing the dry film on the board surface by using a chemical method, removing the redundant copper on the board surface and reserving the required circuit.

7. The rework method of electroplating hard gold infiltration on PCB board as recited in claim 1, characterized in that: further comprises an outer layer inspection step: and (5) checking the quality of the board surface by using an automatic optical detection device, and if the quality does not meet the requirement, marking.

8. The rework method of electroplating hard gold on PCB board as recited in claim 7, further comprising the step of marking: the plate surface is printed with the required mark.

9. The rework method of electroplating hard gold infiltration on PCB board as recited in claim 1, characterized in that: in the sand blasting step, before sand blasting, the green oil on the surface is cured and is subjected to pre-drying treatment.

10. The rework method of electroplating hard gold infiltration on PCB board as recited in claim 9, characterized in that: in the sand blasting step, the temperature of pre-drying is set to be 150 ℃, and the time of pre-drying is set to be 15 min.

Technical Field

The invention relates to the field of circuit boards, in particular to a rework method for hard gold plating and gold infiltration of a PCB.

Background

At present, with the miniaturization trend of electronic devices, the volume of electronic components is smaller and smaller, and the arrangement density is higher and higher. Printed circuit boards, also known as printed circuit boards, are providers of electrical connections for electronic components. To increase the area over which wiring can be routed, more single or double sided wiring boards have been used for multilayer boards. A printed circuit board with two inner layers and two outer layers or two inner layers and two outer layers is made up through alternative arrangement of positioning system and insulating adhesive material, and interconnection of conducting patterns according to design requirement.

However, the existing PCB has the following disadvantages in the manufacturing process:

in the manufacturing process of a common high-multilayer once-pressed hard gold PCB, a dry film of the gold alloy can loosen before or during the hard gold electroplating of the PCB after the gold alloy electroplating, gold infiltration can occur in the hard gold electroplating process (the position of the gold infiltration needs to be etched), a thin gold layer at the gold infiltration position cannot react with an etching solution in a film stripping etching process, so that a corrosion resistance problem (the part needing to be etched is not etched) occurs in the film stripping etching process, the PCB can be short-circuited in the end of the condition, the outer layer AOI can only be repaired, the repairing process is slow, the gold infiltration short circuit at the position with a small distance cannot be manually repaired at all, and the PCB can be scrapped and has high scrappage.

Disclosure of Invention

In order to overcome the defects of the prior art, one of the objectives of the present invention is to provide a rework method for electroplating hard gold and gold on a PCB, which can solve the problem of high scrap rate.

One of the purposes of the invention is realized by adopting the following technical scheme:

a rework method for electroplating hard gold and gold-infiltrated PCB comprises the following steps:

prefabricating and processing steps: processing a PCB inner layer plate material with required size, manufacturing a required circuit pattern on the PCB inner layer plate material after the processes of film pasting, exposure, etching and film removing, and bonding and curing the hot-melt plastic with an inner layer copper surface and a copper foil;

finishing and processing steps: removing the glue flowing and curing part at the plate edge in the pressing process to enable the plate edge to be neat and smooth, punching and realizing subsequent interlayer signal interconnection, and depositing copper and plating copper on the hole and the plate surface;

a primary outer layer processing step: pasting, exposing and developing to expose the required pattern on the PCB, and thickening the copper, nickel and gold in the hole and on the surface of the PCB to the required degree;

secondary outer layer processing: carrying out secondary film pasting, exposure and development to expose the required pattern on the PCB;

electroplating hard gold: electroplating the hard gold pattern area with the thickness of the hard gold required by the customer by using a chemical method;

and (3) film stripping: removing dry films on the primary and secondary outer layer processing pastes of the board surface to expose the part to be etched;

electroplating detection: checking whether the part to be etched has gold penetration or not, if so, executing the next step;

and an abnormal plate processing step: applying for a film by using a nitrogen sheet, setting a gold-infiltrated part as a film windowing part, and setting a non-gold-infiltrated part as a film non-windowing part; printing a required solder mask layer on the surface and in the hole of the PCB, performing green oil and exposure treatment, and performing development treatment after exposure;

sand blasting step: spraying the diamond sand to the film windowing part to remove the gold at the gold-infiltrated part.

Further, after the secondary outer layer processing step and before the hard gold electroplating step, an outer layer detection step is arranged: checking whether a dry film adhered to the outer layer in one-time processing is loosened, if so, removing the film of the abnormal PCB, applying for a film by using a nitrogen sheet, setting a hard gold graph part of the PCB as a film windowing part, setting a non-hard gold graph part as a film non-windowing part, printing a solder mask layer required by a customer on the surface and in the hole of the PCB, developing, and electroplating hard gold again to the required thickness; if not, the step of electroplating hard gold is executed.

Abnormal plate processing step

Further, in the prefabrication step: and (3) bonding and curing the hot-melt plastic PP with the inner copper surface and the copper foil.

Furthermore, in the finishing step, after the hole is punched, impurities on the surface of the plate are removed, and the copper surface is roughened.

Further, the method also comprises the steps of degreening the green oil: and removing the green oil on the surface of the plate by using NaOH solution.

Further, the method also comprises a film removing and etching step: and removing the dry film on the board surface by using a chemical method, removing the redundant copper on the board surface and reserving the required circuit.

Further, the method also comprises an outer layer inspection step: and (5) checking the quality of the board surface by using an automatic optical detection device, and if the quality does not meet the requirement, marking.

Further, the method also comprises the following identification steps: the plate surface is printed with the required mark.

Further, in the blasting step, the green oil on the surface is cured and subjected to a pre-drying treatment before blasting.

Further, if the infiltration gold is found after the film stripping of the electroplated hard gold, in the sand blasting step, the pre-drying temperature is set to be 150 ℃, and the pre-drying time is set to be 15 min.

Compared with the prior art, the invention has the beneficial effects that:

checking whether a dry film attached to the once outer layer processing is loosened, applying for a film by using a nitrogen sheet, setting a graph part without the dry film loosening as a film non-windowing part, and setting a graph part with the dry film loosening as a film windowing part; in the film windowing part, removing a dry film on the whole board surface of the abnormal board, printing a required solder mask layer on the board surface and in the hole of the PCB, performing green oil treatment, and performing development treatment after the green oil treatment; spraying the diamond sand to the film windowing part to remove the gold at the gold-infiltrated part. The method adopts a detection and continuous treatment mode to repair the electroplated gold-infiltrated part, solves the problem of high rejection rate of the circuit board, saves the cost and improves the economic benefit.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a flow chart of a rework method of hard gold plating of PCB board according to a preferred embodiment of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, a rework method of hard gold plating and gold infiltration for a PCB includes the following steps:

prefabricating and processing steps: processing a PCB inner layer plate material with required size, manufacturing a required circuit pattern on the PCB inner layer plate material after the processes of film pasting, exposure, etching and film removing, and bonding and curing the hot-melt plastic with an inner layer copper surface and a copper foil;

preferably, in the prefabrication step: and (3) bonding and curing the hot-melt plastic PP with the inner copper surface and the copper foil.

Finishing and processing steps: removing the glue flowing and curing part at the plate edge in the pressing process to enable the plate edge to be neat and smooth, punching and realizing subsequent interlayer signal interconnection, and depositing copper and plating copper on the hole and the plate surface;

preferably, in the finishing step, after the hole is punched, impurities on the surface of the plate are removed, and the copper surface is roughened.

A primary outer layer processing step: pasting, exposing and developing to expose the required pattern on the PCB, and thickening the copper, nickel and gold in the hole and on the surface of the PCB to the required degree;

secondary outer layer processing: carrying out secondary film pasting, exposure and development to expose the required pattern on the PCB;

electroplating hard gold: electroplating the hard gold pattern area with the thickness of the hard gold required by the customer by using a chemical method;

and (3) film stripping: removing dry films on the primary and secondary outer layer processing pastes of the board surface to expose the part to be etched;

electroplating detection: checking whether the part to be etched has gold penetration or not, if so, executing the next step;

and an abnormal plate processing step: applying for a film by using a nitrogen sheet, setting a gold-infiltrated part as a film windowing part, and setting a non-gold-infiltrated part as a film non-windowing part; printing a required solder mask layer on the surface and in the hole of the PCB, performing green oil and exposure treatment, and performing development treatment after exposure; abnormal plate processing step

Sand blasting step: spraying the diamond sand to the film windowing part to remove the gold at the gold-infiltrated part. The method adopts a detection and continuous treatment mode to repair the electroplated gold-infiltrated part, solves the problem of high rejection rate of the circuit board, saves the cost and improves the economic benefit.

Preferably, if the infiltrated gold is found after the stripping of the electroplated hard gold, in the sand blasting step, the green oil on the surface is cured and pre-dried before the sand blasting. The temperature of pre-drying is set to 150 ℃, and the time of pre-drying is set to 15 min.

Specifically, if the problem of hard gold penetration during electroplating is found before the hard gold electroplating, the principle is described as follows: the hard gold electroplating or water gold electroplating process can plate copper, nickel and water gold on partial positions of the PCB, and the positions have height difference with the positions not plated with water gold. And the green oil has stronger fluidity than the dry film under the condition of liquid, and even if the height difference exists between the water gold electroplating position and the non-water gold electroplating position of the PCB after the water gold electroplating, the gap between the electroplating position and the non-electroplating position can be well combined and filled with the green oil. The binding force between the pre-dried green oil and the position of the gold without water is stronger, so that the gold infiltration can not occur in the rework process of electroplating hard gold of the PCB.

Specifically, if the problem of hard gold penetration in electroplating is found after hard gold electroplating, the principle is described as follows: the green oil has strong fluidity under the condition of liquid, and is well combined and filled with an electroplating hard gold layer and a water gold electroplating layer. The pre-dried green oil has stronger binding force, so that the hard gold plating layer/water gold plating layer below the gold-infiltrated PCB can be protected by the green oil in the sand blasting process. The sand blasting is to use a physical method, the carborundum rubs with the gold layer at the gold infiltration position to remove the gold at the gold infiltration position, and finally the aim of rework is achieved.

Oil-green fading step: and removing the green oil on the surface of the plate by using NaOH solution.

A step of stripping and etching: and removing the dry film on the board surface by using a chemical method, removing the redundant copper on the board surface and reserving the required circuit.

And (3) outer layer inspection: and (5) checking the quality of the board surface by using an automatic optical detection device, and if the quality does not meet the requirement, marking.

Identification: the plate surface is printed with the required mark.

Preferably, after the secondary outer layer processing step and before the hard gold electroplating step, an outer layer detection step is provided: checking whether a dry film attached to the once outer layer machining is loosened, if so, applying a film by using a nitrogen sheet, setting a hard gold graphic part of the PCB as a film windowing part, setting a non-hard gold graphic part as a film non-windowing part, printing a solder mask layer required by a customer on the surface and in the hole of the PCB, developing, and electroplating hard gold again to the required thickness; if not, the step of electroplating hard gold is executed.

Specifically, if gold infiltration occurs, the method is adopted to operate, and the problems can be solved before or after the hard gold is electroplated; if no gold penetration occurs, the multilayer once-pressed hard gold PCB mainly has the following manufacturing process:

cutting the large-size PCB inner layer plate material into the required small PCB inner layer plate material;

an inner layer IDF step: manufacturing a circuit pattern required by a customer on an inner layer plate of the PCB through film pasting, exposure, etching and film removing processes;

inner layer AOI step: inspecting the defects of the inner-layer pattern plate by using an optical principle;

pressing a plate: carrying out hot melting on the solid PP, and carrying out bonding and final curing on the hot-melted PP, the inner-layer copper surface and the copper foil to realize subsequent interlayer signal insulation and interconnection;

trimming: removing the glue flowing and curing part at the plate edge in the pressing process to ensure that the plate edge is neat and smooth;

drilling: drilling a hole required by a customer to realize subsequent interlayer signal interconnection;

deburring: removing impurities on the surface of the plate and roughening the copper surface;

copper deposition: depositing a thin layer of copper in the holes and on the plate surface by a chemical method to play a role in conduction;

plate plating: plating a thin layer of copper in the holes and on the plate surface by a chemical method to play a role in conduction and prepare for a subsequent 'gold-in-water copper electroplating' process;

outer layer IDF1 step: exposing a graph required by a customer on the PCB through film pasting, exposure and development processes;

and (3) gold plating: thickening the copper in the hole and the PCB surface, and plating nickel and thin gold to meet the requirement of customers on copper thickness, nickel thickness and thin gold thickness;

outer layer IDF2 step: exposing a hard gold pattern which is required to be electroplated by a client on the PCB through the processes of film pasting, exposure and development;

electroplating hard gold: electroplating the hard gold thickness required by a customer on the electroplating hard gold pattern area by a chemical method;

and (3) film stripping: removing the dry film on the board surface by a chemical method, and preparing an etching step for subsequent etching: removing redundant copper on the board surface, and reserving the circuit required by a customer;

outer layer AOI step: using the optical principle to inspect the quality of PCB surface;

green oil step: printing a solder mask layer required by a customer on the surface and the hole of the PCB;

character step: the identification required by the customer is printed on the PCB surface, so that subsequent PCB part installation is facilitated.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.