CN112566382A

CN112566382A - Novel resistance welding pretreatment processing method

Info

Publication number: CN112566382A
Application number: CN201910854456.7A
Authority: CN
Inventors: 钟吉潘
Original assignee: Shennan Circuit Co Ltd
Current assignee: Shennan Circuit Co Ltd
Priority date: 2019-09-10
Filing date: 2019-09-10
Publication date: 2021-03-26

Abstract

The application discloses novel resistance welding pretreatment processing method, which comprises the following steps: preparing a plate to be treated, and carrying out plate grinding processing on the plate to be treated; carrying out novel bonding agent treatment on the plate to be treated after the plate grinding; the novel bonding agent mainly comprises a reactive polymer, the reactive polymer at least comprises a nitrogen-containing group and an R group, and the novel solder resist pretreatment processing method is used for processing the PCB, so that the connection of chemical bonds can be generated only through chemical reactions among the novel bonding agent, a copper surface and printing ink under the condition of not controlling the thickness, the roughness and the specific surface area range of the PCB, and the problems of windowing, oil dropping and bad dirt of the PCB are solved.

Description

Novel resistance welding pretreatment processing method

Technical Field

The application relates to the field of circuit board solder mask, in particular to a novel solder mask pretreatment processing method.

Background

Printed Circuit Boards (PCBs) are providers of electrical connections for electronic components, and with the development of society, the requirements for the performance of the PCBs are increasing.

The solder mask process is an important process in the PCB manufacturing process, ink is transferred to the circuit board to form a pattern consistent with the negative film, the solder mask ink film is a protective film and can prevent bridging during solder mask, a long-time insulating environment and chemical protection resistance are provided, and before the solder mask process is carried out, the PCB needs to be treated to a certain degree so that the board surface and the solder mask layer have good binding force.

The existing solder mask pretreatment processing mode mainly comprises a first-generation volcanic ash grinding plate and a second-generation super-roughening processing, wherein the roughness of the super-roughening processing is large, so that the solder mask oil removal problem can be well solved, but the proportion of dirt caused by the large specific surface area of the super-roughening processing is quite obvious in the post-processing step; meanwhile, the plate processed by the volcanic ash grinding plate shows that the solder resist ink has obvious oil loss; the current processing mode can not completely meet the quality requirement, and a new resistance welding pretreatment process needs to be found to solve the problems of oil removal by windowing and obvious dirt at the same time.

Disclosure of Invention

The technical problem mainly solved by the application is to provide a novel resistance welding pretreatment processing method, and the resistance welding pretreatment processing method can simultaneously solve the problems of windowing oil dropping and bad dirt in a PCB.

In order to solve the technical problem, the application adopts a technical scheme that: preparing a plate to be treated, and grinding the plate to be treated; carrying out novel bonding agent treatment on the plate to be treated after the plate grinding; wherein the composition of the novel bonding agent comprises a reactive polymer, and the composition of the reactive polymer at least comprises a nitrogen-containing group and an R group.

The plate to be processed comprises a substrate and a copper surface, wherein the copper surface is arranged on one side of the substrate, and the copper surface forms the plate surface of the plate to be processed.

And the plate grinding processing is to perform volcanic ash plate grinding processing on the plate surface of the plate to be processed.

The volcanic ash grinding plate is characterized in that a mixture of volcanic ash and water is sprayed on the plate surface to remove oxides and stains on the plate surface.

Wherein the novel bonding agent treatment is to coat the novel bonding agent on the board surface of the board to be treated.

Wherein the novel bonding agent has the formula: n- (BTH-3006) -R, wherein N represents said nitrogen-containing group and R represents said R group.

The novel bonding agent has an action mechanism of Cu … … N- (BTH3006) -R-resin, wherein the nitrogen-containing group reacts with the copper surface in one way, and the R group reacts with the resin contained in the ink in the subsequent solder resist process in another way.

Wherein the result of said one reaction is a bond between said copper and said nitrogen-containing group; the other reaction is a linkage where the resin and the R group create a chemical bond.

In order to solve the above technical problem, another technical solution adopted by the present application is: provided is a printed wiring board, the structure of which includes: a substrate; the copper surface is arranged on one side of the substrate, and the other side of the copper surface is coated with a novel bonding agent; an ink layer covering the other side of the novel bonding agent, wherein the ink layer has a thickness of at least 5 microns.

The beneficial effect of this application is: different from the prior art, the novel processing method for the resistance welding pretreatment is characterized in that a board is processed by adopting a method of grinding the board and a novel bonding agent, and under the condition that the thickness of the PCB, the roughness of the board and the range of the specific surface area do not need to be controlled, the novel bonding agent is connected with a chemical bond generated by a chemical reaction between a copper surface and printing ink, so that the problems of oil falling and obvious dirt falling during windowing the PCB are solved.

Drawings

FIG. 1 is a schematic flow chart of an embodiment of a novel method for processing solder resist pretreatment provided by the present application;

FIG. 2 is a schematic flow chart of another embodiment of the novel method for processing solder resist pretreatment provided by the present application;

FIG. 3 is a schematic diagram illustrating the reaction mechanism of an embodiment in a subsequent solder resist process provided herein;

fig. 4 is a schematic structural diagram of a PCB board after a solder mask process in an embodiment provided in the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments that can be obtained by a person skilled in the art based on the embodiments in this application without any creative effort belong to the protection scope of this application, and in addition, the description of the upper, lower, left, right, etc. used in this application is only relative to the mutual position relationship of the components in this application in the drawings.

At present, the processing mode of the resistance welding pretreatment is mainly the first generation of volcanic ash grinding plate and the second generation of super-roughening processing, and the problems of windowing oil removal and bad dirt are mainly solved by the method.

The problem of oil dropping during windowing is that the first generation of volcanic ash grinding plates are used for processing, but the surface roughness of the processed PCB is low, and ink cannot be well adsorbed, so that the thickness of the ink at the windowing position, particularly the small windowing position, is insufficient, and the ink at the edge part of a hole ring/line is influenced by the fluidity of the ink before high-temperature curing in the subsequent solder resisting processing process, the ink at the edge part of the hole ring/line can flow towards the lower part, so that the ink at the corner position is thin, and the thin position of the ink is separated from a copper surface after being attacked by immersion of the chemical gold liquid medicine in the chemical gold melting process after curing, so that the problem of whitening and oil dropping is further caused.

The problem of poor dirt is that after the second generation of super-roughening processing is adopted, the PCB has larger roughness, the problem of windowing and oil dropping is solved, but after the PCB is subjected to the super-roughening processing, the PCB also has larger specific surface area, the dirt proportion brought by the larger specific surface area is quite obvious in the post-process, and nearly 100% of dirt on the silver melting plate (the plate with the plate thickness exceeding the capability of the plate grinding machine can be only subjected to the super-roughening processing) is poor.

Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of the novel method for processing solder resist pretreatment of the present application.

S11: preparing a plate to be treated, and grinding the plate to be treated.

Before the solder resist processing of the PCB, the solder resist pretreatment processing needs to be carried out in advance, so that the board surface of the PCB meets the requirements of no oxide layer, no oil stain and no other stains, and the printing ink can be smoothly adhered to the copper surface.

The method comprises the steps of firstly carrying out resistance welding pretreatment processing on a PCB needing resistance welding processing so as to facilitate adhesion of an ink layer in the resistance welding processing, and carrying out plate grinding processing on the surface of the PCB so as to remove stains such as oxides, oil stains, fingerprint dust and the like possibly existing on the surface of the PCB. The grinding plate is divided into a physical grinding plate and a chemical grinding plate, wherein the physical grinding plate generally refers to a volcanic ash grinding plate, and the chemical grinding plate generally refers to a PCB plate subjected to microetching cleaning treatment by using chemical liquid (such as sulfuric acid and NPS metal acid washing or alkali washing).

S12: and (3) treating the plate to be treated after the plate grinding process by using a novel bonding agent, wherein the novel bonding agent comprises a reactive polymer, and the reactive polymer at least comprises a nitrogen-containing group and an R group.

After removing oxides and stains, coating the novel bonding gold on the surface of the PCB plate, and covering a layer of novel bonding agent on the copper surface of the PCB plate.

The novel bonding agent BTH-3006 used in the present application comprises a reactive polymer having a composition comprising at least a nitrogen-containing group and an R group, wherein, the nitrogen-containing group can react with copper on the copper surface to generate chemical bond connection, and the R group can also react with resin in the solder resist ink covering the PCB surface in the subsequent solder resist process to generate chemical bond connection, therefore, during the processing of the pre-treatment of the solder resist, the roughness, the specific surface area and the thickness of the PCB plate after the pre-treatment of the solder resist are not required to be considered, only the BTH-3006 bonding agent is used for bonding the copper surface and the ink and has certain bonding force, the bonding agent also reduces the problem of undesirable smudging because the bonding agent reacts only with copper and ink to create a bond.

Referring to fig. 2, fig. 2 is a schematic flow chart of another embodiment of the novel method for processing solder resist pretreatment of the present application.

S21: and spraying the mixture of the volcanic ash and the water on the board surface to remove oxides and stains on the board surface.

In the manufacturing process of the PCB, the surface of the board is easily stained with fingerprints, dust, oil stains, and other stains, and the metal material on the surface is also easily oxidized with oxygen in the air to form oxides, so that in order to improve the bonding force between the solder resist ink and the surface of the PCB in the solder resist process, the surface of the PCB needs to have a certain degree of cleanliness.

In this embodiment, a volcanic ash board grinding process is preferably used for board grinding and cleaning of the surface of the PCB, and the specific steps are as follows: spraying a mixture of volcanic ash and water on a PCB surface, carrying out plate grinding and cleaning on the PCB surface sprayed with the volcanic ash mixture by using a volcanic ash grinding brush, washing off the volcanic ash mixture and cleaned stains by using high-pressure water after cleaning is finished, and finally carrying out plate drying treatment to obtain a dry PCB with certain cleanliness, wherein the concentration of the volcanic ash in the mixture of the volcanic ash and the water is preferably 12% -18%, the plate grinding speed is controlled within the range of 2-3m/min, and the washing high pressure is controlled between 15-18 bar.

S22: and coating the novel bonding agent on the board surface of the board to be treated.

The bonding agent used in this example is a novel bonding agent BTH-3006, the main component of which is a reactive polymer (the reactive polymer is a polymer having a chemically functional group, also called functionalized polymer), and the reactive polymer at least includes a nitrogen-containing group and an R group, wherein the nitrogen-containing group can react with copper to generate a chemical bond connection, and the R group can also react with a resin contained in the solder resist ink in the solder resist process and also generate a chemical bond connection.

Wherein, the composition of the novel bonding agent can be simply expressed as: n- (BTH-3006) -R, N represents a nitrogen-containing group, R represents an R group, wherein the action mechanism of the novel bonding agent for improving the adhesion of the copper surface can also be simply expressed as follows: cu... N- (BTH-3006) -R-resin, wherein the resin is a main component in solder resist ink provided in a subsequent solder resist process.

Therefore, when the novel bonding agent is used for carrying out resistance welding pretreatment processing and then a PCB is subjected to resistance welding process, the copper surface coated with the BTH-3006 can generate chemical bond connection only through chemical reactions between the BTH-3006 and the copper surface and between the BTH-3006 and the printing ink without controlling the roughness and the specific surface area of the copper surface, so that the printing ink and the copper surface have good binding force, the problem of windowing and oil dropping is reduced, and meanwhile, the BTH-3006 only reacts with the BTH-3006 and generates chemical bond connection, so that the problem of poor dirt of the PCB is reduced.

Therefore, when the PCB processed by the method for processing before solder mask in this embodiment is subjected to subsequent solder mask processing, the problem of self-roughness and specific surface area does not need to be considered, the novel bonding agent is directly used to enable the ink to have a certain binding force with the copper surface, and the occurrence of poor windowing oil dropping and dirt is reduced, please refer to fig. 3, which is a schematic diagram of a reaction mechanism in the subsequent solder mask process in an embodiment of the present application.

The chemical reaction is carried out on the copper surface 11, wherein the bonding agent (BTH-3006)17 comprises an R group 14, a reactive polymer 16 and a nitrogen-containing group 12, and the bonding agent (BTH-3006)17 is arranged between the copper surface 11 and the ink layer 15, wherein the R group 14 and the ink layer 15 are chemically reacted to generate a chemical bond 13, and the nitrogen-containing group 12 and the copper surface 11 are reacted to generate a chemical bond 18, so that a certain bonding force is generated between the copper surface 11 and the ink layer 15.

In the existing method for processing before solder resisting, the binding force between ink and a board surface is improved through certain roughness, and the phenomenon of bad dirt on a PCB is reduced through certain specific surface area, but simultaneously, the problem of small window oil dropping can be solved through enough roughness, but the specific surface area is too large to cause bad dirt, the problem of bad dirt can be solved through proper specific surface area, but the roughness can also cause window oil dropping because of being too small.

The novel solder resist pretreatment processing method adopted in this embodiment: firstly, removing oxides and stains on the surface of a PCB (printed Circuit Board) by using a volcanic ash grinding plate, and then coating BTH-3006 on the surface of the PCB, wherein a certain binding force can be kept between a copper surface and printing ink only by relying on the reaction of a novel bonding agent and the copper surface and the reaction of the novel bonding agent and resin in solder resist printing ink to generate chemical bonds, and meanwhile, the bonding agent only reacts with the copper surface and the printing ink to generate the connection of the chemical bonds, so that the phenomenon of windowing oil dropping and bad dirt of the PCB is reduced, therefore, the novel solder resist pretreatment method can simultaneously solve the problem of windowing oil dropping and bad dirt of the PCB on the basis of not considering the roughness, the specific surface area and the thickness of the PCB.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a PCB board after a solder mask process in an embodiment of the present application.

The structure comprises a substrate 21, a copper surface 11 and an ink layer 31, wherein the substrate 21, the copper surface 11 and the ink layer 31 are sequentially overlapped, the substrate 21 is positioned at the lowest part, the copper surface 11 is arranged on the upper side of the substrate 21, the copper surface 11 does not completely cover the substrate 21, the ink layer 31 is arranged on the upper side of the copper surface 11, and the ink layer 31 completely covers the copper surface 11.

After the PCB plate of this embodiment has carried out and has hindered processing of hindering the preceding processing, hinder it, hinder the printing ink to the PCB plate and hinder and carry out protection processing with the circuit on the plate, cover printing ink on the PCB plate after BTH-3006 coating, expose to develop out the circuit figure on the PCB face, make the printing ink layer produce gluing simultaneously and paste and cover on the copper face, carry out the high temperature cure at last in order to form one deck printing ink protection film, the thickness of this printing ink protection layer is 5 microns at least. In the solder resist processing process, the adhesion of the novel bonding agent to the copper surface and the printing ink and the certain thickness of the printing ink protective layer prevent the printing ink from flowing before high-temperature curing, so that the phenomenon of windowing and oil dropping is reduced, and meanwhile, the novel bonding agent BTH-3006 only adheres to the copper surface and the printing ink, so that the phenomenon of bad dirt is also reduced.

That is, the novel solder resist pretreatment processing method adopted in the present example: firstly, removing oxides and stains on the surface of a PCB (printed Circuit Board) by using a volcanic ash grinding plate, and then coating BTH-3006 on the surface of the PCB, wherein a certain binding force is kept between a copper surface and printing ink through the reaction of a novel bonding agent and the copper surface and the reaction of the novel bonding agent and resin in solder resist printing ink, and meanwhile, the bonding agent only reacts with the copper surface and the printing ink to form the connection of the chemical bonds, so that the phenomenon that the PCB is poor in oil removal and dirt due to windowing is reduced, therefore, the novel solder resist pretreatment method can simultaneously solve the problem that the PCB is poor in oil removal and dirt due to windowing on the basis of not considering the roughness, the specific surface area and the thickness of the PCB.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings, or which are directly or indirectly applied to other related technical fields, are intended to be included within the scope of the present application.

Claims

1. A novel solder resist pretreatment processing method is characterized in that,

preparing a plate to be treated, and grinding the plate to be treated;

carrying out novel bonding agent treatment on the plate to be treated after the plate grinding;

wherein the composition of the novel bonding agent comprises a reactive polymer, and the composition of the reactive polymer at least comprises a nitrogen-containing group and an R group.

2. The novel processing method of the pre-solder mask treatment as claimed in claim 1, wherein the board to be treated comprises a substrate and a copper surface, the copper surface is arranged on one side of the substrate, and the copper surface constitutes a board surface of the board to be treated.

3. The novel pre-solder mask processing method according to claim 1, wherein the board grinding process is to subject the board surface of the board to be processed to volcanic ash board grinding.

4. The novel processing method for pre-solder mask treatment as claimed in claim 3, wherein the volcanic ash grinding plate is prepared by spraying a mixture of volcanic ash and water on the plate surface to remove oxides and stains on the plate surface.

5. The novel processing method of the pre-solder resist treatment as claimed in claim 1, wherein the novel bonding agent treatment is a coating of the novel bonding agent on the board surface of the board to be treated.

6. The novel processing method for the pre-treatment of the solder resist as set forth in claim 1, wherein the chemical formula of the novel bonding agent is: n- (BTH-3006) -R, wherein N represents said nitrogen-containing group and R represents said R group.

7. The novel processing method for pre-solder resist treatment as claimed in claim 6, wherein the novel bonding agent has a mechanism of action of Cu … … N- (BTH3006) -R-resin, wherein the nitrogen-containing group reacts with the copper surface in one kind, and the R group reacts with the resin contained in the ink in the subsequent solder resist process in another kind.

8. The novel pre-solder resist processing method according to claim 7, wherein the result of the reaction is a bond between the copper surface and the nitrogen-containing group; the other reaction is a linkage where the resin and the R group create a chemical bond.

9. A printed wiring board, comprising:

a substrate;

the copper surface is arranged on one side of the substrate, and the other side of the copper surface is coated with a novel bonding agent;

an ink layer covering the other side of the novel bonding agent, wherein the ink layer has a thickness of at least 5 microns.

10. The printed wiring board of claim 9, wherein the printed wiring board is prepared by the novel solder resist pretreatment processing method of any one of claims 1 to 8.