阅读说明：本技术 一种防止pcb板沉铜铜面粗糙的加工方法 (Processing method for preventing copper deposition and copper surface of PCB from being rough ) 是由 李仕武 王景贵 谢明运 汤湘平 欧阳泽 于 2021-08-23 设计创作，主要内容包括：本发明属于PCB板加工技术领域,具体涉及一种防止PCB板沉铜铜面粗糙的加工方法,包括如下步骤：步骤S1、沉铜前加工,对PCB板进行钻孔,并对完成钻孔的PCB板进行烘烤,固化孔壁；步骤S2、沉铜处理,包括步骤S21超声波水洗和步骤S22除油；在步骤S21中,对经过垂直沉铜线中和处理后的PCB板进行超声波水洗,使用过滤系统装置过滤超声波水洗产生的杂质,在步骤S22中,使用超声波设备对除油缸内的PCB板进行振动反吸附；步骤S3、板面电镀,完成加工。本发明的防止PCB板沉铜铜面粗糙的加工方法,能够减少PCB板填料脱落,防止脱落填料被反吸附并堆积在板面上,降低沉铜铜面粗糙度,改善产品品质。(The invention belongs to the technical field of PCB processing, and particularly relates to a processing method for preventing a copper-deposited copper surface of a PCB from being rough, which comprises the following steps: step S1, before copper deposition, drilling the PCB, baking the drilled PCB, and solidifying the hole wall; step S2, copper deposition treatment, including step S21 ultrasonic water washing and step S22 deoiling; in step S21, performing ultrasonic water washing on the PCB subjected to neutralization treatment by the vertical copper deposition line, filtering impurities generated by the ultrasonic water washing by using a filtering system device, and in step S22, performing vibration anti-adsorption on the PCB in the oil removal cylinder by using ultrasonic equipment; and step S3, electroplating the board surface to finish the processing. The processing method for preventing the copper-deposited copper surface of the PCB from being rough can reduce the falling of the filler of the PCB, prevent the falling filler from being reversely adsorbed and accumulated on the surface of the PCB, reduce the roughness of the copper-deposited surface and improve the product quality.)

1. A processing method for preventing copper deposition and copper surface roughness of a PCB is characterized by comprising the following steps:

step S1, processing before copper deposition, including drilling holes on the PCB according to functional requirements, baking the PCB after drilling holes, and solidifying hole walls;

step S2, copper deposition treatment, including step S21 ultrasonic water washing and step S22 deoiling; in the step S21, performing ultrasonic water washing on the PCB subjected to neutralization treatment by the vertical copper deposition line, filtering impurities generated by the ultrasonic water washing by using a filtering system device, and in the step S22, performing vibration and anti-adsorption on the PCB in the oil removal cylinder by using an ultrasonic device;

and step S3, electroplating the board surface to finish the processing.

2. The processing method of claim 1, wherein in step S1, the baking temperature of the PCB is 160 ℃ -180 ℃, and the baking time is 1.5 hours-2.5 hours.

3. The processing method for preventing the copper deposition and the copper surface roughness of the PCB as claimed in claim 1, wherein the step S21 specifically comprises the following steps:

s211, carrying out first ultrasonic washing, wherein the filtering system device is arranged in an ultrasonic washing cylinder, and filtering resin fillers which are vibrated and shed off in the first ultrasonic washing process of the PCB;

step S212, carrying out ultrasonic washing for the second time, wherein the filtering system device continues to filter the resin filler dropped and remained in the ultrasonic washing cylinder;

and S213, carrying out ultrasonic washing for the third time, wherein the filtering system device continuously filters the resin filler in the ultrasonic washing cylinder.

4. The processing method for preventing the copper deposition and surface roughening of the PCB as claimed in claim 1, wherein in step S21, the filter element of said filtering system device is periodically replaced with 1 replacement cycle.

5. The processing method for preventing the copper deposition and the copper surface roughness of the PCB as claimed in claim 1, wherein the step S22 specifically comprises the following steps:

step S221, deoiling for the first time, setting the concentration of the liquid medicine to be X concentration, and carrying out physical vibration on the PCB by using the ultrasonic equipment;

step S222, hot water washing, namely washing the PCB after the first deoiling by using hot water;

and S223, removing oil for the second time, setting the concentration of the liquid medicine to be Y concentration, wherein the Y concentration is more than or equal to X concentration, and continuously using the ultrasonic equipment to carry out physical vibration on the PCB.

6. The processing method for preventing copper deposition on copper surface of PCB as claimed in claim 1, wherein in step S22, the generator power of said ultrasonic device is 2000W-2500W.

7. The processing method according to claim 5, wherein in step S221, the frequency of replacing the oil removing cylinder is 2 times/week; in step S223, the frequency of cylinder replacement of the oil removal cylinder is 1 time/week.

8. The processing method according to claim 5, wherein in step S221, the concentration of X is in the range of 400ppm to 600 ppm; in the step S223, the concentration of Y ranges from 600ppm to 800 ppm.

9. The processing method for preventing the copper deposition and surface roughening of the PCB as claimed in any one of claims 1-8, wherein in step S2, the step S21 is preceded by the steps of: upper plate → first micro-etching → swelling → washing → first glue removal → second glue removal → recycling washing → pre-neutralization → high water washing → neutralization.

10. The processing method for preventing the copper deposition and surface roughening of the PCB as claimed in any one of claims 1-8, wherein in step S2, the step S22 is followed by the steps of: water washing → second micro-etching → water washing → acid leaching → deionized water washing → presoaking → activation → deionized water washing → chemical copper → water washing → oxidation prevention → water washing → lower plate.

Technical Field

The invention relates to the technical field of PCB (printed circuit board) processing, in particular to a processing method for preventing a copper-deposited copper surface of a PCB from being rough.

Background

The PCB, i.e., the printed wiring board, is a carrier for electrical connection of electronic components and is fabricated by electronic printing. The PTH process, namely the copper deposition process, is applied to the production and processing of the printed circuit board with through holes, and aims to deposit a layer of copper on a hole wall substrate of a nonconductor formed after the drilling of the printed circuit board through a series of chemical treatment methods, and thicken the copper through a subsequent electroplating method to meet the designed copper thickness requirement. Along with the development of the electronic industry towards high frequency and high speed, increasingly strict requirements are put forward on the signal transmission performance of the PCB, and besides stricter control is performed on precise circuit manufacturing in the PCB industry, the signal transmission speed and the signal integrity are improved mainly by selecting a high frequency and high speed material with lower dielectric loss. However, the high-frequency and high-speed materials are greatly different from conventional FR4 materials (composite materials such as epoxy glass fiber boards) in the resin constituting system and the filler. The high-frequency high-speed material is easy to fall off in the copper deposition process, and the fallen filler absorbs the surfactant in the liquid medicine in the oil removing groove, is reversely absorbed by the printed circuit board and is accumulated on the board surface, so that the roughness problem is generated on the surface and in the hole of the printed circuit board, and the product quality is influenced.

Disclosure of Invention

The invention aims to provide a processing method for preventing a copper-deposited copper surface of a PCB from being rough, which can reduce the falling of fillers of the PCB, prevent the falling fillers from being absorbed reversely and accumulated on the PCB, reduce the roughness of the copper-deposited surface and improve the product quality.

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

a processing method for preventing copper deposition copper surface of a PCB from being rough comprises the following steps:

step S1, processing before copper deposition, including drilling holes on the PCB according to functional requirements, baking the PCB after drilling holes, and solidifying hole walls;

step S2, copper deposition treatment, including step S21 ultrasonic water washing and step S22 deoiling; in the step S21, performing ultrasonic water washing on the PCB subjected to neutralization treatment by the vertical copper deposition line, filtering impurities generated by the ultrasonic water washing by using a filtering system device, and in the step S22, performing vibration and anti-adsorption on the PCB in the oil removal cylinder by using an ultrasonic device;

and step S3, electroplating the board surface to finish the processing.

As a preferred embodiment of the present invention, in the step S1, the PCB board is baked at a temperature of 160 ℃ to 180 ℃ for a baking time of 1.5 hours to 2.5 hours.

As a preferred embodiment of the present invention, in the step S21, the method specifically includes the following steps:

s211, carrying out first ultrasonic washing, wherein the filtering system device is arranged in an ultrasonic washing cylinder, and filtering resin fillers which are vibrated and shed off in the first ultrasonic washing process of the PCB;

step S212, carrying out ultrasonic washing for the second time, wherein the filtering system device continues to filter the resin filler dropped and remained in the ultrasonic washing cylinder;

and S213, carrying out ultrasonic washing for the third time, wherein the filtering system device continuously filters the resin filler in the ultrasonic washing cylinder.

In a preferred embodiment of the present invention, in step S21, the filter element of the filtration system device is periodically replaced, and the replacement period is 1 time/week.

As a preferred embodiment of the present invention, in the step S22, the method specifically includes the following steps:

step S221, deoiling for the first time, setting the concentration of the liquid medicine to be X concentration, and carrying out physical vibration on the PCB by using the ultrasonic equipment;

step S222, hot water washing, namely washing the PCB after the first deoiling by using hot water;

and S223, removing oil for the second time, setting the concentration of the liquid medicine to be Y concentration, wherein the Y concentration is more than or equal to X concentration, and continuously using the ultrasonic equipment to carry out physical vibration on the PCB.

In a preferred embodiment of the present invention, in step S22, the generator power of the ultrasonic device is 2000W to 2500W.

As a preferred embodiment of the present invention, in the step S221, the frequency of cylinder replacement of the oil removal cylinder is 2 times/week; in step S223, the frequency of cylinder replacement of the oil removal cylinder is 1 time/week.

As a preferred embodiment of the present invention, in the step S221, the concentration of X ranges from 400ppm to 600 ppm; in the step S223, the concentration of Y ranges from 600ppm to 800 ppm.

As a preferred embodiment of the present invention, in the step S2, the step S21 is preceded by the following steps: upper plate → first micro-etching → swelling → washing → first glue removal → second glue removal → recycling washing → pre-neutralization → high water washing → neutralization.

As a preferred embodiment of the present invention, in the step S2, the step S22 is further followed by the steps of: water washing → second micro-etching → water washing → acid leaching → deionized water washing → presoaking → activation → deionized water washing → chemical copper → water washing → oxidation prevention → water washing → lower plate.

The invention has the beneficial effects that: the processing method for preventing the copper deposition and the copper surface roughness of the PCB improves the existing PCB processing technology, bakes the drilled PCB, solidifies the hole wall base material, increases the bonding strength of the pressed PCB, and avoids the falling of the filler on the hole wall caused by drilling; ultrasonic washing is carried out on the PCB subjected to neutralization treatment of the vertical copper precipitation wires by using ultrasonic washing equipment provided with a filtering system device, and resin filler precipitated in the ultrasonic washing process is filtered; the oil removing cylinder is provided with ultrasonic equipment, the PCB surface after ultrasonic washing is subjected to physical vibration in the oil removing process, the risk of reverse adsorption of falling fillers on the PCB surface is reduced, the falling fillers accumulated on the PCB surface are reduced, the copper surface roughness of copper deposition is reduced, and the product quality is improved.

Drawings

FIG. 1 is a schematic flow chart of a processing method for preventing copper deposition and copper surface roughness of a PCB according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of the copper deposition process according to the embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

As shown in fig. 1 and fig. 2, an embodiment of the present invention provides a processing method for preventing copper deposition and copper surface roughness of a PCB, including the following steps:

step S1, processing before copper deposition, including drilling holes on the PCB according to the functional requirements, baking the PCB after drilling holes, and solidifying the hole walls;

in this embodiment, step S1 further includes a pressing plate process, and drilling holes in the multilayer wiring board formed after the pressing plate process. And baking the drilled PCB, solidifying the hole wall base material, increasing the bonding strength of the PCB after pressing, and avoiding the falling of the filler on the hole wall caused by drilling.

Step S2, copper deposition treatment, including step S21 ultrasonic water washing and step S22 deoiling; in step S21, performing ultrasonic water washing on the PCB subjected to neutralization treatment by the vertical copper precipitation wire, filtering impurities generated by the ultrasonic water washing by using a filtering system device, and in step S22, performing vibration and anti-adsorption on the PCB in the de-oiling cylinder by using ultrasonic equipment;

in step S2, the copper deposition process includes a plurality of process steps. Before the ultrasonic water washing at step S21, the PCB board has completed the vertical copper plating line neutralization process. The ultrasonic water washing device is provided with a filter system device, preferably the filter system device comprises a filter pump. Ultrasonic washing makes the PCB board produce physical vibration to can have the resin filler that drops to produce, the filter pump can filter the resin filler that drops, avoids the resin filler to be adsorbed to PCB board face by the resorption in subsequent technology. In the step S22, ultrasonic equipment is arranged in the oil removing cylinder, the risk of reverse adsorption of the falling filler on the board surface is reduced through physical vibration, and the falling filler accumulated on the surface of the PCB board is reduced.

And step S3, electroplating the board surface to finish the processing.

According to the processing method for preventing the copper deposition and the copper surface roughness of the PCB, the existing PCB processing technology is improved, the drilled PCB is baked, the hole wall base material is solidified, the bonding strength of the pressed PCB is increased, and the phenomenon that the filling material on the hole wall falls off due to drilling is avoided; ultrasonic washing is carried out on the PCB subjected to neutralization treatment of the vertical copper precipitation wires by using ultrasonic washing equipment provided with a filtering system device, and resin filler precipitated in the ultrasonic washing process is filtered; the oil removing cylinder is provided with ultrasonic equipment, the PCB surface after ultrasonic washing is subjected to physical vibration in the oil removing process, the risk of reverse adsorption of falling fillers on the PCB surface is reduced, the falling fillers accumulated on the PCB surface are reduced, the copper surface roughness of copper deposition is reduced, and the product quality is improved.

Further, in step S1, the temperature for baking the PCB is 160 ℃ to 180 ℃ and the baking time is 1.5 hours to 2.5 hours. In the embodiment, the set baking temperature is 170 ℃, and the baking time is 2 hours, so that the hole wall can be effectively cured, and the damage to the PCB caused by long-time high-temperature baking can be prevented.

Further, in step S21, the method specifically includes the following steps:

s211, carrying out first ultrasonic washing, arranging a filtering system device in an ultrasonic washing cylinder, and filtering resin fillers which are vibrated and shed off in the ultrasonic washing process of the PCB;

step S212, carrying out ultrasonic washing for the second time, and continuously filtering the resin filler dropped and remained in the ultrasonic washing cylinder by the filtering system device;

and S213, carrying out ultrasonic washing for the third time, wherein the filtering system device continuously filters the resin filler in the ultrasonic washing cylinder. In this embodiment, be provided with cubic ultrasonic water washing to the PCB board after the heavy copper wire neutralization treatment of perpendicular altogether, use the filler that drops that separates out in the filtration washing jar of filtration system device in cubic ultrasonic water washing process continuously for it is more thorough to the filtration that drops the filler. Further, in step S21, the filter element of the filter system device needs to be replaced periodically, and the replacement period is 1 time/week. Preferably, the filter element adopts a cotton core, has good adsorption performance on resin filler, is low in price and reduces the processing cost. In other embodiments, other filter elements and replacement cycles can be adopted according to actual process requirements and equipment use frequency, and the embodiment is not limited herein.

Further, in step S22, the method specifically includes the following steps:

s221, deoiling for the first time, setting the concentration of the liquid medicine to be X concentration, and carrying out physical vibration on the PCB by using ultrasonic equipment;

step S222, hot water washing, namely washing the PCB subjected to the first deoiling by using hot water;

and step S223, deoiling for the second time, setting the concentration of the liquid medicine to be Y concentration, wherein the concentration of Y is more than or equal to the concentration of X, and continuously using ultrasonic equipment to carry out physical vibration on the PCB. Through the steps, the content of the liquid medicine for the first oil removal and the second oil removal is adjusted, so that the concentration of the liquid medicine for the second oil removal is higher than that of the liquid medicine for the first oil removal, on one hand, the adsorption quantity of the falling filler to the surfactant in the liquid medicine during the first oil removal is reduced, the copper surface roughness of the PCB is reduced, and on the other hand, the oil removal effect is ensured through the concentration of the liquid medicine for the second oil removal. Preferably, the concentration of the liquid medicine in the first oil removal is 400ppm-600ppm, and the concentration of the liquid medicine in the second oil removal is 600ppm-800ppm, which can be selected and set according to the actual process.

Further, in step S22, the generator power of the ultrasonic device is 2000W-2500W. In the embodiment, the generator power is 2100W, the ultrasonic device can generate enough vibration frequency, and the risk that the resin filler is absorbed on the surface of the PCB board is reduced. In other embodiments, the generator with other power may be selected for the ultrasonic device according to the material and process requirements of the PCB, which is not limited herein.

Further, in step S221, the frequency of cylinder replacement of the divided cylinder is 2 times/week, and in step S223, the frequency of cylinder replacement of the divided cylinder is 1 time/week. Because more falling fillers are separated out in the first oil removing process, the frequency of cylinder replacement is improved, and excessive falling fillers are prevented from being accumulated in the oil removing cylinder.

Further, in step S2, step S21 is preceded by the following steps: upper plate → first micro-etching → swelling → washing → first glue removal → second glue removal → recycling washing → pre-neutralization → high water washing → neutralization. The PCB after the above steps has vertically deposited copper wire, and enters into ultrasonic water washing process after neutralization treatment.

Further, in step S2, the following steps are included after step S22: water washing → second micro-etching → water washing → acid leaching → deionized water washing → presoaking → activation → deionized water washing → chemical copper → water washing → oxidation prevention → water washing → lower plate. After ultrasonic washing and twice oil removal, the PCB needs to be subjected to the above process, all process steps of copper deposition treatment are completed, and the step S3 can be performed for board surface electroplating.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.