阅读说明：本技术 一种pcb板的制造方法及pcb板 (Manufacturing method of PCB and PCB ) 是由 李仕武 汤湘平 欧阳泽 王景贵 谢明运 于 2021-09-30 设计创作，主要内容包括：本发明涉及PCB板生产技术领域,公开了一种PCB板的制造方法及PCB板。PCB板上设置有走线孔,PCB板的制造方法包括以下步骤：步骤S1：对走线孔的孔壁进行除杂处理,具体包括：步骤S11：利用除胶溶液去除走线孔的孔壁上的胶渣；步骤S12：利用中和溶液对除胶后的PCB板进行中和处理,其中,中和溶液为中和剂和水的混合溶液,且中和溶液中中和剂的含量为100mL/L～140mL/L；步骤S2：利用活化溶液对去除杂质后的PCB板进行活化处理；步骤S3：对活化处理后的PCB板进行还原处理；步骤S4：对完成还原反应的PCB板进行沉铜处理,以使走线孔的孔壁上沉积铜层。本发明通过对生产工序中中和处理阶段进行改良,解决了沉铜效果不佳的问题,提高生产效率的同时降低了生产成本。(The invention relates to the technical field of PCB production, and discloses a PCB manufacturing method and a PCB. The PCB is provided with wiring holes, and the manufacturing method of the PCB comprises the following steps: step S1: carry out edulcoration to the pore wall of walking the line hole and handle, specifically include: step S11: removing the glue residues on the hole wall of the wiring hole by using a glue removing solution; step S12: neutralizing the PCB subjected to glue removal by using a neutralizing solution, wherein the neutralizing solution is a mixed solution of a neutralizer and water, and the content of the neutralizer in the neutralizing solution is 100-140 mL/L; step S2: carrying out activation treatment on the PCB with the impurities removed by using an activation solution; step S3: carrying out reduction treatment on the PCB after the activation treatment; step S4: and carrying out copper deposition treatment on the PCB subjected to the reduction reaction so as to deposit a copper layer on the hole wall of the wiring hole. The invention solves the problem of poor copper deposition effect by improving the neutralization treatment stage in the production process, improves the production efficiency and reduces the production cost.)

1. A manufacturing method of a PCB board is provided with wiring holes, and is characterized by comprising the following steps:

step S1: to carry out edulcoration processing, specifically include the pore wall of walking the line hole:

step S11: removing the glue residues on the hole wall of the wiring hole by using a glue removing solution;

step S12: neutralizing the PCB subjected to glue removal by using a neutralizing solution to remove the glue removing solution and a glue removing reactant which are remained on the surface of the PCB and the hole wall of the wiring hole, wherein the neutralizing solution is a mixed solution of a neutralizing agent and water, and the content of the neutralizing agent in the neutralizing solution is 100-140 mL/L;

step S2: performing activation treatment on the PCB with impurities removed by using an activation solution so that palladium ions in the activation solution are adsorbed on the hole wall of the wiring hole;

step S3: reducing the PCB after the activation treatment so as to reduce the palladium ions into metal palladium;

step S4: and carrying out copper deposition treatment on the PCB which is subjected to the reduction reaction so as to deposit a copper layer on the hole wall of the wiring hole under the catalysis of metal palladium.

2. The method for manufacturing a PCB board of claim 1, wherein the step S1 further comprises, after the step S12:

step S13: carrying out hole finishing treatment on the PCB by using an oil removing solution so as to remove oil stains on the surface of the PCB and the hole wall of the wiring hole;

step S14: carrying out microetching treatment on the deoiled PCB by using a microetching solution so as to remove oxides on the surface of the PCB and the hole wall of the wiring hole;

step S15: and performing pre-dipping treatment on the PCB after the micro-etching treatment.

3. The method for manufacturing a PCB panel as claimed in claim 2, wherein between the step S12 and the step S13 further comprising:

step S12': under a pressure of 50kg/cm²～70kg/cm²The wiring hole is washed with water under the condition of (1).

4. The method for manufacturing a PCB of claim 2, wherein in the step S15, the pre-dipping agent used in the pre-dipping process has a pH value of 1.5-3.5.

5. The method for manufacturing a PCB of claim 1, wherein the step S4 specifically comprises:

step S41: immersing the PCB into a copper deposition solution and enabling the PCB to be opposite to a first water jet, and spraying the copper deposition solution into the wiring hole by using a first circulating pump to control the first water jet, wherein the frequency of the first circulating pump is 45Hz, and the flow rate of the first water jet is 65-85L/min;

step S42: and transferring the PCB to be right opposite to a second water jet, and controlling the second water jet to spray the copper deposition solution into the routing hole by using a second circulating pump, wherein the frequency of the second circulating pump is 48Hz, the flow rate of the second water jet is 75-95L/min, and the first water jet and the second water jet are both positioned in the copper deposition solution.

6. The method for manufacturing a PCB board of claim 1, wherein the step S1 further comprises, before the step S11:

step S10: and swelling the glue residue on the hole wall of the wiring hole by using a swelling solution.

7. The method of claim 1, wherein the activating solution used in the activating treatment is a mixed solution of an activator and water, and the content of palladium ions in the activator is 0.11g/L to 0.13g/L in the step S2.

8. The method for manufacturing a PCB board according to claim 1, further comprising after the step S4:

step S5: and drying the PCB subjected to the copper deposition treatment.

9. A PCB panel manufactured by the method of manufacturing a PCB panel according to any one of claims 1 to 8.

10. The PCB board of claim 9, wherein the inner wall of the wiring hole of the PCB board forms a copper layer with a thickness of 0.38 μm to 0.64 μm.

Technical Field

The invention relates to the technical field of PCB production, in particular to a PCB manufacturing method and a PCB.

Background

The PCB, also called a printed circuit board, is an important electronic component, a support for electronic components, and a provider for electrical connection of electronic components. The cross-layer micro via (Skip via) is one of blind hole connection implementation modes between adjacent layers of the PCB. With the continuous development of science and technology, the requirements for wiring and signal transmission of lines are higher and higher, the wiring space in the PCB is insufficient due to more wiring requirements in the PCB, and the cross-layer micro-via design is generally applied to the PCB at present based on the design wiring and signal requirements. When the PCB is produced, laser drilling and mechanical drilling are generally adopted, a cross-layer micro-via hole is drilled on the laminated PCB, and then copper plating is completed by adopting copper deposition and pulse plating manufacturing modes. The most important is the copper deposition process, which mainly has the main function of depositing a uniform conductive layer on the hole wall through the redox reaction of the cross-layer micro via hole of the multilayer PCB, and then electroplating, thickening and plating copper to achieve the purpose of a loop.

However, in the prior art, the content of the neutralizer in the neutralization solution used in the neutralization treatment of the copper deposition process is low, so that the concentration difference of the solution inside and outside the cross-layer micro via hole is small, the solution is diffused into the hole through the concentration difference at the orifice, and the small concentration difference can cause the poor liquid medicine exchange effect inside and outside the cross-layer micro via hole, so that the adjustment effect on the glass fiber yarns of the hole wall of the cross-layer micro via hole is poor, the adsorption effect of the hole wall on palladium ions in the activation stage is poor, the poor backlight of copper deposition at the bottom of the hole is easy to occur in the copper deposition stage, and finally, the problem of no copper in the hole is caused.

Therefore, it is desirable to provide a method for manufacturing a PCB and a PCB, so as to solve the above problems.

Disclosure of Invention

The invention aims to provide a PCB manufacturing method and a PCB, which solve the problem of poor copper deposition effect, improve the production efficiency and reduce the production cost.

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

a manufacturing method of a PCB board is provided with wiring holes and comprises the following steps:

step S1: to carry out edulcoration processing, specifically include the pore wall of walking the line hole:

step S11: removing the glue residues on the hole wall of the wiring hole by using a glue removing solution;

step S12: neutralizing the PCB subjected to glue removal by using a neutralizing solution to remove the glue removing solution and a glue removing reactant which are remained on the surface of the PCB and the hole wall of the wiring hole, wherein the neutralizing solution is a mixed solution of a neutralizing agent and water, and the content of the neutralizing agent in the neutralizing solution is 100-140 mL/L;

step S2: performing activation treatment on the PCB with impurities removed by using an activation solution so that palladium ions in the activation solution are adsorbed on the hole wall of the wiring hole;

step S3: reducing the PCB after the activation treatment so as to reduce the palladium ions into metal palladium;

step S4: and carrying out copper deposition treatment on the PCB which is subjected to the reduction reaction so as to deposit a copper layer on the hole wall of the wiring hole under the catalysis of metal palladium.

Optionally, the step S1 further includes, after the step S12:

step S13: carrying out hole finishing treatment on the PCB by using an oil removing solution so as to remove oil stains on the surface of the PCB and the hole wall of the wiring hole;

step S14: carrying out microetching treatment on the deoiled PCB by using a microetching solution so as to remove oxides on the surface of the PCB and the hole wall of the wiring hole;

step S15: and performing pre-dipping treatment on the PCB after the micro-etching treatment.

Optionally, between the step S12 and the step S13, further comprising:

step S12': under a pressure of 50kg/cm²～70kg/cm²The wiring hole is washed with water under the condition of (1).

Optionally, in the step S15, the PH of the presoaking agent used for the presoaking process is 1.5-3.5.

Optionally, the step S4 specifically includes:

step S41: immersing the PCB into a copper deposition solution and enabling the PCB to be opposite to a first water jet, and spraying the copper deposition solution into the wiring hole by using a first circulating pump to control the first water jet, wherein the frequency of the first circulating pump is 45Hz, and the flow rate of the first water jet is 65-85L/min;

step S42: and transferring the PCB to be right opposite to a second water jet, and controlling the second water jet to spray the copper deposition solution into the routing hole by using a second circulating pump, wherein the frequency of the second circulating pump is 48Hz, the flow rate of the second water jet is 75-95L/min, and the first water jet and the second water jet are both positioned in the copper deposition solution.

Optionally, the step S1 further includes, before the step S11:

step S10: and swelling the glue residue on the hole wall of the wiring hole by using a swelling solution.

Optionally, in the step S2, the activation solution used in the activation treatment is a mixed solution of an activator and water, and the content of palladium ions in the activator is 0.11g/L to 0.13 g/L.

Optionally, after the step S4, the method further includes:

step S5: and drying the PCB subjected to the copper deposition treatment.

A PCB board is manufactured by adopting the manufacturing method of the PCB board as any one of the above.

Optionally, the thickness of the copper layer formed on the inner wall of the wiring hole of the PCB board is 0.38 μm to 0.64 μm.

The invention has the beneficial effects that:

according to the manufacturing method of the PCB, the concentration difference between the inside and the outside of the wiring hole is increased by increasing the content of the neutralizing agent in the neutralizing solution in the neutralizing treatment stage, the solution is diffused into the hole at the orifice through the concentration difference, and then the solution in the hole is conveyed in the hole by the circulation of the solution in the hole. Therefore, the content of the neutralizing agent in the neutralizing solution is improved, the exchange rate of the neutralizing solution inside and outside the wiring hole can be enhanced, the adjusting effect on glass fiber filaments in the hole wall of the wiring hole is increased, the effect that palladium ions are adsorbed on the hole wall area of the wiring hole in the activating process is further enhanced, a good reaction environment is provided for subsequent copper deposition treatment, the stability of copper deposition reaction is ensured, the problem of poor copper deposition effect is solved, the raw material utilization rate is improved, and the product quality is ensured. Secondly, the manufacturing method of the PCB provided by the invention can solve the problem that no copper exists in the wiring holes by adopting the mode of primary copper deposition treatment and primary electroplating treatment, and compared with the mode of primary copper deposition treatment, primary electroplating treatment, secondary copper deposition treatment and secondary electroplating treatment in the prior art, the manufacturing method of the PCB has the advantages that the copper deposition effect is ensured, the production flow is simplified, the production efficiency is improved, and the production cost is reduced.

The PCB provided by the invention is manufactured by adopting the manufacturing method of the PCB, a copper layer with uniform thickness can be formed on the inner wall of the wiring hole of the PCB, the copper deposition effect in the wiring hole is ensured, the problem that no copper exists in the wiring hole is avoided, the reliability of the quality of the PCB is further ensured, the production efficiency is improved, and the production cost is reduced.

Drawings

In order to make the description of the embodiments of the present invention or the technical solutions in the prior art more obvious and understandable, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, the drawings described below are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a method for manufacturing a PCB according to an embodiment of the present invention;

fig. 2 is a flowchart of removing impurities from a wiring hole in a method for manufacturing a PCB according to an embodiment of the present invention;

fig. 3 is a flowchart of a copper deposition process in the method for manufacturing a PCB according to an 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.

Fig. 1 shows a flowchart of a method for manufacturing a PCB according to an embodiment of the present invention, fig. 2 shows a flowchart of removing impurities from a wiring hole in the method for manufacturing a PCB according to an embodiment of the present invention, and fig. 3 shows a flowchart of a copper deposition process in the method for manufacturing a PCB according to an embodiment of the present invention. Referring to fig. 1, in the present embodiment, a method for manufacturing a PCB board is provided with a wiring hole, and the method can deposit a uniform conductive layer on the PCB board and the hole wall of the wiring hole through a copper deposition reaction, and then perform electroplating, thickening and copper plating to achieve the purpose of a loop. When the PCB is manufactured, a thin copper foil is covered on the surface of the PCB, and the copper foil surface and the hole wall of the wiring hole are subjected to copper deposition reaction simultaneously. In the embodiment, the PCB is horizontally placed on the production line, and in the corresponding step, the transfer mechanism horizontally immerses the PCB in the corresponding reaction solution for processing. Wherein, transfer mechanism specifically is manipulator or transmission band, and other mechanisms that can realize shifting the PCB board all can be adopted.

In the prior art, the manufacturing method of the PCB board generally comprises: the primary copper deposition treatment, the primary electroplating treatment, the secondary copper deposition treatment and the secondary electroplating treatment are complex in processing process and high in production cost.

In order to solve the above problem, referring to fig. 1 and fig. 2, the present embodiment provides a method for manufacturing a PCB, which specifically includes the following steps:

step S1: carry out edulcoration to the pore wall of walking the line hole and handle, prevent that PCB slab band impurity from getting into the activation tank, protect the activation tank and avoid polluting, also guaranteed the reaction effect of follow-up reduction and heavy copper processing simultaneously, step S1 specifically includes:

step S10: and (5) bulking the glue residues on the hole wall of the wiring hole by utilizing a bulking solution. Specifically, during drilling, in the process of violent friction between a PCB plate material and a drill tip in high-speed rotation, the local temperature is increased, so that the plate material is softened and melted into paste to be coated on the hole wall, the paste becomes glue residue after cooling, the glue residue can cause the quality problem of the wiring hole, and therefore the glue residue in the wiring hole needs to be removed before copper deposition treatment. However, the glue residue is hard after being cooled, the quality of the hole wall of the wiring hole can be affected if the glue residue is directly scraped, and the glue removal is not complete when the glue residue is directly treated by using the glue removal solution, so that the glue residue on the hole wall needs to be softened by using the bulking solution.

Preferably, the leavening solution used for the leavening treatment is a mixed solution of a leavening agent, sodium hydroxide and water. In order to realize good leavening effect, the content of the leavening agent in the leavening solution is 160 mL/L-210 mL/L, the pH value of the sodium hydroxide is 10-12, and the temperature of the leavening treatment is preferably 74-78 ℃.

Furthermore, after the glue residue on the hole wall of the wiring hole is bulked, the PCB and the wiring hole need to be washed for multiple times to wash off the bulked solution remained in the PCB and the wiring hole when the glue residue is bulked, so that the situation that the glue residue on the hole wall of the wiring hole is removed by using the glue removing solution subsequently is prevented, the loose solution is brought into the glue removing solution by the PCB, and the glue removing solution reacts with the loose solution to cause pollution of the glue removing solution. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Further, step S11: and removing the glue residues on the hole wall of the wiring hole by using a glue removing solution. Preferably, the glue removing solution used in the glue removing treatment is a mixed solution of sodium permanganate, sodium manganate, sodium hydroxide and water. In order to realize good degumming effect, the content of the sodium permanganate is 70-80 g/L, the content of the sodium manganate is less than 25g/L, the content of the sodium hydroxide is 40-60 g/L, and the degumming treatment temperature is preferably 74-83 ℃. Wherein, the side reaction is accompanied in the degumming reaction process to generate a byproduct MnO₂Due to the MnO present in the degumming solution remaining after the degumming treatment₂The service life of the degumming solution is seriously influenced, and the quality of the degumming residue is influenced, so that the content of the sodium manganese in the degumming solution needs to be controlled to weaken the occurrence of side reactions. The sodium permanganate solution has strong oxidizing property, and generates oxidation-reduction reaction with the glue residue under the conditions of high temperature and strong alkali, so that the softened glue residue on the hole wall of the wiring hole is decomposed and dissolved.

Furthermore, after the glue residue on the hole wall of the wiring hole is subjected to glue removing treatment, the PCB and the wiring hole need to be washed for multiple times so as to wash off the glue removing solution remained in the holes of the PCB and the wiring hole during glue removing. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Step S12: and neutralizing the PCB subjected to glue removal by using a neutralizing solution to remove the residual glue removing solution and glue removing reactant on the surface of the PCB and the hole wall of the wiring hole. Wherein the degumming reactant is a byproduct MnO generated in the degumming treatment of the step S11₂When the PCB is subsequently subjected to hole-finishing treatment by utilizing the degreasing solution, the residual degreasing solution and the residual degreasing reactant on the surface of the PCB and the hole wall of the wiring hole are brought into the degreasing solution, and can react with the degreasing solution to cause pollution of the degreasing solution, so that the residual degreasing solution and the residual degreasing reactant on the surface of the PCB and the hole wall of the wiring hole are removed by utilizing the neutralizing solution.

Further, in order to ensure the exchange effect of the neutralization solution inside and outside the wire routing hole, the PCB needs to be immersed in the neutralization solution and is opposite to the water knife in the neutralization cylinder, the neutralization solution is sprayed into the wire routing hole by the water knife, and the flow rate of the water knife is 80L/min-100L/min.

Specifically, the neutralization solution is a mixed solution of a neutralizing agent and water, and the content of the neutralizing agent in the neutralization solution is 100 mL/L-140 mL/L. However, in the prior art, a neutralization solution with a neutralizer content of 80mL/L to 100mL/L is usually used for neutralization treatment, and in this embodiment, the content of the neutralizer in the neutralization solution is increased to 100mL/L to 140mL/L, so that the concentration difference between the inside and the outside of the wiring hole is increased, the diffusion effect of the neutralization solution in the wiring hole is improved, the exchange efficiency of the neutralization solution inside and outside the wiring hole is further enhanced, the adjustment effect on the glass fiber filaments in the hole wall of the wiring hole is increased, the effect of palladium ion adsorption of the hole wall area of the wiring hole in the activation treatment is further enhanced, a good reaction environment is provided for the subsequent copper deposition treatment, and the stability of the copper deposition reaction is ensured.

Preferably, the neutralizing agent is a mixed solution of reducing detergent, hydrogen peroxide and 50% strength sulfuric acid. In order to ensure good neutralization effect, the contents of the reducing detergent, the hydrogen peroxide and the 50% sulfuric acid are respectively as follows: 30mL/L to 40mL/L, 13mL/L to 17mL/L, and 90mL/L to 110 mL/L.

Furthermore, after the hole wall of the wiring hole is neutralized, the PCB and the wiring hole need to be washed for many times to wash away the neutralizing solution remained in the PCB and the wiring hole during glue removal. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Further, step S13: and (4) utilizing an oil removing solution to carry out hole finishing treatment on the PCB so as to remove oil stains on the surface of the PCB and the hole wall of the wiring hole. If oil stains exist on the surface of the PCB and the hole wall of the wiring hole, the binding force between the copper precipitation layer and the surface of the copper foil and between the copper precipitation layer and the hole wall can be influenced, and even the situation that copper cannot be precipitated on the surface of the copper foil or the hole wall of the wiring hole can occur. Therefore, in order to improve the bonding force between the copper plating layer and the surface of the copper foil and the hole wall of the wiring hole, the wiring hole of the PCB needs to be cleaned in time by using a degreasing solution.

Further, in order to ensure a good oil removing effect, the PCB needs to be immersed in the oil removing solution and aligned with the water jet in the entire hole cylinder, and the oil removing solution is sprayed into the routing hole by the water jet, wherein the flow rate of the water jet is 50L/min to 70L/min. Preferably, the content of the oil removing agent in the oil removing solution is 35 mL/L-45 mL/L, and the temperature of the pore-adjusting treatment is preferably 48-52 ℃.

Furthermore, after the hole wall of the wiring hole is subjected to hole trimming treatment, the PCB and the wiring hole need to be washed for multiple times so as to wash away the oil removing solution remained in the PCB and the wiring hole during hole trimming. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Further, between the step S12 and the step S13, the method further includes:

step S12': under a pressure of 50kg/cm²～70kg/cm²The wiring hole is washed with water under the condition (1). In the prior art, the wiring hole is generally cleaned by common washing, but the pressure intensity of the common washing is small, and some hole plugging substances remained in the wiring hole cannot be completely removed, so that the hole plugging substances enter the wiring holeThereby affecting the reaction effect of the whole pore treatment. In this example, a pressure of 50kg/cm was used²～70kg/cm²The high-pressure water washing is used for washing the wiring hole, so that hole plugging substances possibly existing in drill cuttings, base material scraps and the like which are remained in the wiring hole can be more thoroughly cleaned.

However, the water pressure of the high-pressure water washing is very strong, the cleaning effect is also very strong, and for the wiring hole with difficult solution exchange, the too strong cleaning effect can weaken the adjusting effect of neutralization treatment on the glass fiber on the hole wall of the wiring hole, and can play a negative role instead. Therefore, in the present embodiment, specifically, the switch for high-pressure water washing is turned on after step S12 to turn on the high-pressure water washing mode, and the switch for high-pressure water washing is turned off before step S13 to turn on the normal water washing mode.

Step S14: and carrying out microetching treatment on the deoiled PCB by using a microetching solution so as to remove oxides on the surface of the PCB and the hole wall of the wiring hole. The inner layer of the wiring hole is provided with a pad which is communicated with the wiring hole and used for welding components, the surface of the pad is covered with a thin copper foil, and the oxides on the surface of the PCB and the hole wall of the wiring hole are specifically copper oxides generated by oxidizing the surface of the copper foil. Get rid of the oxide on PCB board surface and the pore wall of walking the line hole, can carry out the alligatoring to the surface of PCB board and the surface of pad, make the surface form little concave type hole to increase the area of contact on PCB board surface and pad surface, strengthen the tooth ability between copper foil surface and the heavy copper layer, guarantee to have good cohesion between follow-up heavy copper layer and the copper foil layer.

Further, in order to ensure the exchange effect of the micro-etching solution inside and outside the wiring hole, the PCB is immersed in the micro-etching solution and is aligned to the water jet in the micro-etching cylinder, and the micro-etching solution is sprayed into the wiring hole by the water jet, wherein the flow rate of the water jet is 80L/min to 100L/min.

Preferably, the microetching treatment is carried out using a mixed solution of 50% sulfuric acid, sodium persulfate and water. In order to ensure good Wei microetching effect, the content of 50% sulfuric acid and sodium persulfate is 40-70 mL/L and 70-110 g/L respectively, and the microetching treatment temperature is preferably 32-36 ℃.

Furthermore, after the micro-etching treatment is performed on the hole wall of the wiring hole, the PCB board and the wiring hole need to be washed with water for many times to wash away the micro-etching solution remained in the PCB board and the wiring hole during the micro-etching. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Step S15: and performing pre-dipping treatment on the PCB after the micro-etching treatment. The presoaking treatment is to effectively wet the hole wall of the wiring hole, prevent moisture on the PCB from entering the activation tank, change the concentration and the PH value of the activation solution, protect the activation tank from being polluted by the micro-etching solution and prolong the service life of the activation tank.

Further, in order to ensure the exchange effect of the presoaking agent inside and outside the routing hole, the PCB is immersed in the presoaking agent and is opposite to the water jet in the presoaking cylinder, the presoaking agent is sprayed into the routing hole by the water jet, and the flow rate of the water jet is 80L/min to 100L/min.

Preferably, the pH value of the presoaking agent is 1.5-3.5, wherein Cu²⁺The content of (A) is less than 0.08g/L, and the temperature of the pre-dipping treatment is 20-35 ℃. It should be noted that the pre-impregnant had substantially the same composition as the activation solution, except that it did not contain palladium ions. Wherein if Cu²⁺The content of (A) is higher, the PCB board will be Cu²⁺Brought into the activation tank to cause decomposition and precipitation of the activation solution, thereby affecting the effect of the activation reaction. Therefore, in order to ensure that the pre-impregnation effect is good and the quality of the activation solution is not affected, it is necessary to control Cu in the pre-impregnation treatment²⁺The content of (a).

Step S2: and (3) carrying out activation treatment on the PCB after the impurities are removed by using an activation solution so that palladium ions in the activation solution are adsorbed on the hole wall of the wiring hole. The hole wall of the wiring hole can be adsorbed with a layer of palladium ions through activation treatment, the palladium ions have strong catalytic capacity, and can catalyze and start chemical copper deposition reaction, so that the uniformity, continuity and compactness of subsequent copper deposition reaction are ensured, and the subsequent chemical copper plating reaction is smoothly carried out on the surface of the whole catalytically treated hole wall.

Furthermore, in order to ensure the exchange effect of the activation solution inside and outside the routing hole, the PCB is immersed in the activation solution and is aligned to the water jet in the activation cylinder, and the activation solution is sprayed into the routing hole by the water jet, wherein the flow rate of the water jet is 80L/min to 100L/min.

Preferably, the activating solution used in the activating treatment is a mixed solution of an activating agent and water, in order to ensure good activating effect, the content of palladium ions in the activating agent is 0.11 g/L-0.13 g/L, and the temperature of the activating treatment is 48 ℃ to 52 ℃. In the prior art, when a PCB is activated, an activation solution containing colloidal palladium is generally used, tin ions in the colloidal palladium activation solution play a role in stabilizing colloids around palladium ions, but the tin ions are not a catalyst in chemical copper deposition, and the palladium ions are exposed outside to play a role in catalysis only through a degumming step, the PCB must be immersed in the degumming solution after activation, and once the tin ions are oxidized in the air, tin oxides are generated and are difficult to remove, and the palladium ions are easily condensed on the surface of the pore wall of the wiring hole while the degumming is performed, so that the activity of the catalyst is reduced. In the embodiment, the activation solution containing palladium ions is used for activating the PCB, the palladium ion activation solution does not contain tin ions, and the activation solution containing palladium ions is simple to prepare and wide in application process range, so that the activation solution containing palladium ions has long service life and good stability, and the defects that the uniformity and the adhesive force of chemical copper deposition are influenced because a layer of tin ions are adsorbed on the surface of the hole wall of the wiring hole in the activation treatment by the activation solution containing colloidal palladium can be overcome.

Furthermore, after the hole wall of the wiring hole is activated, the PCB board and the wiring hole need to be washed with water for many times to wash away the activating solution remained in the PCB board and the wiring hole during activation. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Step S3: and carrying out reduction treatment on the PCB after the activation treatment so as to reduce palladium ions into metal palladium. The metal palladium has strong catalytic capability and can directly and effectively catalyze and start the chemical copper deposition reaction. Further, in order to ensure the exchange effect of the reducing solution inside and outside the wiring hole, the PCB needs to be immersed in the reducing solution and aligned with the water jet in the reducing cylinder, and the reducing solution is sprayed into the wiring hole by the water jet, wherein the flow rate of the water jet is 80L/min to 100L/min. Preferably, the content of the reducing agent in the reducing solution is 5mL/L to 14mL/L, and the temperature of the reducing treatment is 33 ℃ to 37 ℃. In the present embodiment, any reducing agent capable of achieving reduction treatment may be employed.

Furthermore, after the hole wall of the wiring hole is subjected to reduction treatment, the PCB board and the wiring hole need to be washed with water for multiple times to wash away the reducing solution remained in the PCB board and the wiring hole during reduction. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Step S4: and carrying out copper deposition treatment on the PCB subjected to the reduction reaction so as to deposit a copper layer on the hole wall of the wiring hole under the catalysis of metal palladium. In order to ensure the exchange effect of the copper deposition solution inside and outside the wiring hole, the copper deposition treatment process immerses the PCB in the copper deposition solution, and a uniform copper layer is formed on the hole wall of the wiring hole through chemical copper deposition reaction under the catalytic action of a metal palladium catalyst. Preferably, the copper deposition solution is a mixed solution of a stabilizer, a copper deposition additive, a complexing agent, formaldehyde and sodium hydroxide, wherein the content of the stabilizer in the copper deposition solution is 10%, the content of the copper deposition additive is 42 mL/L-63 mL/L, the content of the complexing agent is 80 mL/L-110 mL/L, the concentration of the formaldehyde is preferably 28%, the content of the formaldehyde is 14 mL/L-21 mL/L, and the content of the sodium hydroxide is 8 g/L-10 g/L. Copper deposition additive for providing Cu for chemical copper deposition reaction²⁺A source; complexing agents for Cu inhibition²⁺Generating copper hydroxide precipitate under alkaline condition; the stabilizer has the function of stabilizing the copper deposition solution, ensures that the copper deposition solution cannot be naturally decomposed, stabilizes the copper deposition solution, and can also improve the performance of a copper layer and prevent side reaction; the formaldehyde is used as a reducing agent for the chemical copper deposition reaction, the sodium hydroxide is used as a pH regulator for the chemical copper deposition reaction, and the formaldehyde can have reducibility under the strong alkali condition, so that the sodium hydroxide can provide an alkaline environment for the copper deposition reaction, and the chemical copper deposition of the formaldehyde is ensuredReduction in the reaction.

Further, after step S3, the palladium ions on the hole walls of the wiring holes are reduced to metallic palladium, and metallic copper can be deposited only in the presence of catalytic metallic palladium, and the generated metallic copper can be used as the basis of self-catalysis, Cu²⁺On the basis of the catalysis, the copper can be reduced to metallic copper continuously until the reduction is carried out.

Specifically, the copper precipitation solution added with formaldehyde can generate side reactions under strong alkaline conditions regardless of use. First, Cu²⁺Under the strong alkaline condition, the copper oxide reacts with formaldehyde to generate cuprous oxide which is easy to generate disproportionation reaction to form Cu and Cu²⁺The small particles of copper are randomly dispersed in the solution to become small activation centers, so that the whole copper deposition solution is used as a reaction center, and the copper deposition solution is rapidly and naturally decomposed, therefore, in the copper deposition treatment, the concentration of copper ions in the copper deposition solution needs to be controlled, and further, the copper deposition speed needs to be controlled. Secondly, the formaldehyde undergoes a disproportionation reaction (connizzaro reaction), i.e., a chemical reaction between formaldehyde and sodium hydroxide. Therefore, once formaldehyde is added into the copper deposition solution, the reaction starts, and the reaction is always carried out regardless of the use state or the standing state, so that the consumption of the formaldehyde in the copper deposition solution is high, after the copper deposition solution stops reacting, the pH value of the copper deposition solution needs to be adjusted again, and an automatic adding device needs to be adopted to supplement the formaldehyde into the copper deposition solution. The automatic adding device is the prior art, and the specific structure and the working principle of the automatic adding device are not described in detail in the embodiment.

Further, tests prove that the main factors influencing the copper deposition speed are as follows: 1) pH value of the solution: increasing the pH value, accelerating the deposition of metallic copper, and if the pH value is too high, accelerating the generation of cuprous oxide and Cu²⁺The reduction not only causes the decomposition of the copper solution, but also causes the copper deposition speed to be too fast; when the PH value is reduced, the chemical copper deposition speed is very slow or even stopped, and the surface of the copper layer is passivated when the PH value is too low, so that the PH value needs to be adjusted by adding sodium hydroxide into the copper deposition solution; 2) concentration of the solution: properly increasing Cu in solution²⁺The concentration has obvious influence on the copper deposition speed; 3) concentration of formaldehyde: the concentration of formaldehyde is increased, the copper deposition speed is accelerated, but the copper deposition layer is easy to be rough due to overhigh concentration of formaldehyde; 4) temperature of the copper deposition solution: the temperature of the copper deposition solution is increased, the copper deposition speed can be increased, but the temperature is increased, the catalytic action of copper ions in the copper deposition solution is enhanced, the generation speed of cuprous oxide is increased, the copper deposition quality is poor, the solution is decomposed, but the temperature is too low, the deposition speed of metal copper is slow, and therefore, in the embodiment, the temperature for copper deposition treatment is preferably 31-35 ℃.

Furthermore, after the copper deposition treatment is performed on the hole wall of the wiring hole, the PCB board and the wiring hole need to be washed for multiple times to wash away the copper deposition solution remained in the PCB board and the wiring hole during the copper deposition. The water washing process is a water washing process that is conventional in the art, and this example is not particularly limited thereto.

Further, as shown in fig. 3, step S4 specifically includes:

step S41: immersing the PCB into the copper deposition solution and enabling the PCB to be opposite to the first water jet, and spraying the copper deposition solution into the wiring hole by using a first circulating pump to control the first water jet, wherein the frequency of the first circulating pump is 45Hz, and the flow rate of the first water jet is 65-85L/min;

step S42: and transferring the PCB to be opposite to the second water jet, controlling the second water jet to spray a copper deposition solution into the routing hole by using a second circulating pump, wherein the first water jet and the second water jet are both positioned in the copper deposition solution, the frequency of the second circulating pump is 48Hz, and the flow rate of the second water jet is 75-95L/min.

In this embodiment, improve the jet flow volume of second water sword through the frequency that improves the second circulating pump, can strengthen the exchange effect of the inside and outside heavy copper solution of walking hole, further guaranteed the heavy copper quality on the pore wall of walking hole, solved the bad problem of the heavy copper of pore wall.

Further, step S4 is followed by:

step S5: and drying the PCB subjected to the copper deposition treatment. The PCB after drying treatment is taken off from the production line, the whole PCB is electroplated, a copper layer formed after copper deposition treatment is thickened, the thickness of the PCB is increased to the preset thickness, and good conductivity of the wiring hole is further ensured. The electroplating process is a prior art, and the specific process of the electroplating process is not described in detail in this embodiment.

The embodiment also provides a PCB which is manufactured by adopting the manufacturing method of the PCB. After the series of steps, the thickness of the copper layer formed on the inner wall of the wiring hole of the PCB board is 0.38-0.64 μm. The copper layer is uniform and compact, the problem that no copper exists in the wiring hole is solved, and good conductivity of the wiring hole is guaranteed.

Therefore, the method for manufacturing the PCB provided by the embodiment can solve the problem that no copper exists in the routing holes by adopting the mode of primary copper deposition treatment and primary electroplating treatment, and compared with the mode of primary copper deposition treatment, primary electroplating treatment, secondary copper deposition treatment and secondary electroplating treatment in the prior art, the method has the advantages that the copper deposition effect is ensured, the production flow is simplified, the production efficiency is improved, and the production cost is reduced.

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. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. 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.