CN104066274A - A copper foil surface modification method for printed circuit board manufacturing process - Google Patents

Abstract

A copper foil surface modification method for a printed circuit board process comprises the following steps: preparing a copper foil substrate in advance, cleaning and brushing the surface, spraying horizontally or immersing the surface modifier vertically after the brushing is completed, and finally drying the surface modifier for subsequent processes. Since micro-etching technology is not required in the process, there will be no problem of peroxide corrosion of the machine or heavy metal pollution, and the surface modifier will not change the roughness of the copper surface. At the same time, the bonding strength can be effectively improved for the ultra-thin copper process. Since the surface modification can make the copper foil surface flat, and the dry film residue and residual foot problems of the thin circuit can be completely overcome, the present invention improves the traditional physical super-roughening bonding ability to a chemical bonding effect, so that the overall circuit board process is simplified and clean, and unnecessary costs can be saved.

Description

A copper foil surface modification method for printed circuit board manufacturing process

technical field

The present invention relates to a method for modifying the surface of copper foil used in the manufacturing process of printed circuit boards, and in particular refers to a technology for modifying the surface of copper foil to improve the surface bonding force and simplify and clean the overall printed circuit board manufacturing process , and can save unnecessary costs.

Background technique

In the general printed circuit board manufacturing process, the base board is first cut into work pieces and drilled, and then the through-hole plating is performed. The through-hole plating uses the deposition of copper ions of chemical copper, and a thin layer of copper is adsorbed on the hole wall. Copper layer, so that the two sides start to conduct, and the overall process is pore modifier→water washing→micro-etching→water washing→activation→water washing→speeding→water washing→chemical copper deposition→water washing→drying, after through-hole plating, after After the first copper plating, the dry film is used to make the circuit, and then the printed circuit board that has been plated with copper in the through hole is pressed flat on both sides of the working substrate with an automatic induction laminating machine, and finally exposed , development, line etching, film stripping, solder mask printing, nickel plating, gold plating, fishing molding, and complete the process of printed circuit boards.

In the manufacturing process of printed circuit boards, microetches are mostly used for microetching treatment on the copper surface of printed circuit boards, mainly to correspond to thin lines and effectively improve the adhesion. Green paint pre-treatment, water-based copper protection pre-treatment, tin-spraying pre-treatment or lamination pre-treatment, since the micro-etchants must be micro-etched on the copper surface of the printed circuit board, the micro-etchants themselves are corrosive, so it is easy to The problem of peroxide erosion machine or heavy metal pollution occurs. At the same time, the microetch will make the copper surface uneven and roughen the surface to increase the adhesion of the copper surface, but this will roughen the copper surface. From Figure 1A to It can be seen from Figure 1D that the photos of the copper surface roughness of the medium-roughening microetch agent, super-roughening microetch agent, microetch agent (sodium persulfate+sulfuric acid), and microetch agent (sulfuric acid+ammonia water+stabilizer) were used respectively ( 3000 to 5000 times the SEM photo), and the average surface degree Ra of the four is 0.2 to 0.4um, 0.4 to 0.8um, 0.2 to 0.4um, and 0.2 to 0.4um. Avoid roughening the copper surface.

Therefore, if a copper foil surface modification method for the printed circuit board process can be established, the micro-etching technology is not required, so the roughness of the copper surface will not be changed, and the surface bonding force can be improved at the same time, so that the overall printing The circuit board manufacturing process is simplified and clean, and unnecessary cost is saved, so it should be an optimal solution.

Contents of the invention

The present invention is to provide a copper foil surface modification method for printed circuit board manufacturing process, which refers to a technology for modifying the surface of copper foil to improve the surface bonding force and simplify the overall printed circuit board manufacturing process. Clean, and can save unnecessary costs.

The present invention aims to provide a method for modifying the surface of copper foil used in the process of printed circuit boards. Since the process of surface modification does not require the use of micro-etching technology, it will not cause roughening of the copper surface.

The above-mentioned copper foil surface modification method for printed circuit board manufacturing process can be achieved. The steps are: prepare the copper foil substrate in advance, and perform surface cleaning and brushing; after the brushing is completed, perform degreasing treatment, and wash the copper foil with water After the substrate, the surface modifier is sprayed horizontally or soaked vertically; finally, after washing the copper foil substrate again, the copper foil substrate is dried for subsequent processing.

More specifically, the subsequent process is a lamination process, a dry film lamination process or a solder resist coating process.

More specifically, NaoH or KOH solution is used for degreasing treatment, and the preferred concentration is 3%-5% NaoH or KOH solution by mass fraction.

More specifically, the temperature of the surface modifying agent is 20-30°C.

More specifically, the concentration of the surface modifying agent is 1-5% by volume.

More specifically, the time for horizontally spraying or vertically soaking the surface modifier is 30-60 seconds.

More specifically, the spray pressure of the horizontal spray surface modifying agent is 0.8-1.2kg/cm ² .

More specifically, the temperature for drying the copper foil substrate is 85-95°C.

More specifically, the chemical formula of the surface modifier is (CH ₃ ) ₃ N ⁺ (M) ^- (R ₁ ), wherein (R ₁ ) is a C ₁ -C40 alkyl group or benzene or phenyl group; and (M) is F, Cl, Br, 1, OH or _CH2COO .

More specifically, the chemical formula of the surface modifier is (C ₆ H ₅ )(CH ₃ ) ₂ N ⁺ (M) ^- (R ₁ ), wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or benzene or phenyl; and (M) is F, Cl, Br, 1, OH or _CH2COO .

More specifically, the chemical formula of the surface modifier is (R ₁ )(CH ₃ ) ₂ N ⁺ (M) ^- (R ₂ ), wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or benzene or phenyl; (R ₂ ) is C ₁ to C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

More specifically, the chemical formula of the surface modifier is (R ₁ )(C=N(CH ₂ ) ₂ )N ⁺ (M) ^- (R ₂ )OH, wherein (R ₁ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl; (R ₂ ) is C ₁ to C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

More specifically, the chemical formula of the surface modifier is (R ₁ )(C ₅ H ₄ N)(M) ^- (R ₂ ), wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or benzene or phenyl; (R ₂ ) is C ₁ to C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

More specifically, the chemical formula of the surface modifier is (R ₁ )(CONH)(R ₂ )N ⁺ (CH ₃ ) ₂ (M) ^- , wherein (R ₁ ) is an alkane of C ₁ to C ₄₀ (R ₂ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

More specifically, the chemical formula of the surface modifier is (R ₁ )(CONH)(R ₂ )N ⁺ (R ₃ )SO ₃ ^- , wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or Benzene or phenyl; (R ₂ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl; and (R ₃ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl. .

Description of drawings

FIG. 1A is a SEM photograph of a copper surface roughened with a micro-etch agent at 3000 to 5000 times in the existing printed circuit board manufacturing process.

FIG. 1B is a SEM photo of the copper surface of the existing printed circuit board manufacturing process using super-roughened microetch at 3000 to 5000 times, showing the roughness.

FIG. 1C is a SEM photograph of the copper surface at 3000 to 5000 times of the existing printed circuit board manufacturing process using a microetching agent with sodium persulfate and sulfuric acid, showing its roughness.

FIG. 1D is a SEM photo of the copper surface at 3000-5000 times of the microetching agent with sulfuric acid, ammonia water and stabilizer used in the existing printed circuit board manufacturing process, showing the roughness.

FIG. 2 is a flow chart of a method for modifying the surface of copper foil used in the printed circuit board manufacturing process of the present invention.

Fig. 3 is a SEM photo of the copper surface at 3000-5000 times of a copper foil surface modification method used in the printed circuit board manufacturing process of the present invention, which shows that CSM-1000 does not change the roughness of copper at all.

Fig. 4 is a comparison table of the surface modifying agent used in the copper foil surface modifying method used in the printed circuit board manufacturing process of the present invention and the existing microetch agent.

FIG. 5 is a SEM photograph of the surface of the copper foil at 3000 to 5000 times the result of the first implementation process of a method for modifying the surface of the copper foil used in the printed circuit board manufacturing process of the present invention, showing the degree of roughness.

FIG. 6 is a SEM photo of the surface of the copper foil at 3000-5000 times the result of the second implementation process of the copper foil surface modification method used in the printed circuit board manufacturing process of the present invention, showing its roughness.

FIG. 7A is a SEM photo of the copper foil surface at 3000-5000 times the result of the pretreatment of the existing anti-gold plating dry film, showing its roughness.

7B is a SEM photo of the copper foil surface at 3000 to 5000 times the result of the third implementation process of a copper foil surface modification method used in the printed circuit board manufacturing process of the present invention, showing its roughness.

FIG. 8 is a comparison table of operating costs of chemicals used in a copper foil surface modification method used in the printed circuit board manufacturing process of the present invention.

Among them: the first line in the middle of Figure 5 "line spacing = 4.541minl"; the second line "line width = 1.388mil";

Figure 6: "Line Width = 0.822mil" in the first row from the left, "Line spacing = 0.794mil" in the second row from the left;

In Figure 6, the first line on the right is "line width = 0.727mil", and the second line on the left is "line spacing = 0.843mil".

Detailed ways

The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the drawings.

Please refer to Fig. 2, which is a flow chart of a copper foil surface modification method for printed circuit board manufacturing process of the present invention, the steps of which are:

(1) Prepare the copper foil substrate in advance, and perform surface cleaning and brushing 201;

(2) After brushing and grinding, perform degreasing treatment, and after washing the copper foil substrate, spray horizontally or vertically soak the surface modifier 202;

(3) Finally, after the copper foil substrate is washed with water again, the copper foil substrate is dried to prepare for the subsequent process 203 .

In the above process, the degreasing treatment can use NaoH or KOH solution, preferably 3%-5% NaoH or KOH solution for degreasing treatment, and the temperature of the surface modifying agent is between 20-30 °C and the concentration is The volume percentage is 1-5%, the time for horizontal spraying or vertical immersion of the surface modifier is 30-60 seconds, and the spray pressure of the horizontal spraying surface modifier is 0.8-1.2kg/cm ² ; The temperature is between 85-95°C.

Wherein the surface modifier is cationic, its chemical formula is (CH ₃ ) ₃ N ⁺ (M) ^- (R ₁ ), wherein (R ₁ ) is C ₁ ~ C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, 1, OH or _CH2COO .

Wherein the surface modifier is cationic, and its chemical formula is (C ₆ H ₅ )(CH ₃ ) ₂ N ⁺ (M) ^- (R ₁ ), wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or benzene or phenyl; and (M) is F, Cl, Br, 1, OH or _CH2COO .

Wherein the surface modifier is cationic, and its chemical formula is (R ₁ )(CH ₃ ) ₂ N ⁺ (M) ^- (R ₂ ), wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or benzene or Phenyl; (R ₂ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

Wherein the surface modifier is cationic, and its chemical formula is (R ₁ )(C=N(CH ₂ ) ₂ )N ⁺ (M) ^- (R ₂ )OH, wherein (R ₁ ) is C ₁ ~C ₄₀ (R ₂ ) is C ₁ to C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

Wherein the surface modifying agent is cationic, and its chemical formula is (R ₁ )(C ₅ H ₄ N)(M) ^- (R ₂ ), wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or benzene or Phenyl; (R ₂ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

Wherein the surface modifier is a zwitterion, and its chemical formula is (R ₁ )(CONH)(R ₂ )N ⁺ (CH ₃ ) ₂ (M) ^- , wherein (R ₁ ) is an alkane of C ₁ to C ₄₀ (R ₂ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl; and (M) is F, Cl, Br, l, OH or CH ₂ COO.

Wherein the surface modifier is a zwitterion, and its chemical formula is (R ₁ )(CONH)(R ₂ )N ⁺ (R ₃ )SO ₃ ^- , wherein (R ₁ ) is an alkyl group of C ₁ to C ₄₀ or Benzene or phenyl; (R ₂ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl; and (R ₃ ) is C ₁ -C ₄₀ alkyl or benzene or phenyl.

The copper surface after the copper foil surface modification method (CSM-1000) is shown in Figure 3. Compared with the copper surface roughness diagrams in Figures 1A to 1D, it can be seen that the use of surface modifiers will not change the copper surface roughness, so Can make the copper surface smooth, and further compare the comparative examples of the prior art in the use of medium roughening microetching agent, super roughening microetching agent, microetching agent (sodium persulfate+sulfuric acid), microetching agent (sulfuric acid+ammonia water+ Stabilizer) and the difference of the present invention, as can be seen from the comparison table in Figure 4, since the present invention does not use microetching technology, it will not make the copper surface rough (so there is no copper surface roughness data and there is no microetch-related data); in comparison, the bath solution using the copper foil surface modification method (CSM-1000) is easy to control, free from chlorine pollution, and the operation mode can be continuous, low cost per unit area, low waste liquid treatment cost, It has high binding force with the resist, does not need to be used with pickling and does not need to be used with a copper sulfate recovery machine, although in the comparative examples of the prior art, the coarsening microetching agent, the ultra-roughening microetching agent, and the microetching agent (persulfuric acid Sodium + sulfuric acid), microetching agent (sulfuric acid + ammonia + stabilizer) also have some advantages similar to the surface modification method of copper foil (CSM-1000), but some comparison items are not as good as the present invention, such as medium and thick Both the medium-roughened microetch and the super-roughened microetch have a high binding force to the resist, but the medium-roughened microetch and the super-roughened microetch need to be combined with pickling, so the comparative example is not as good as this one. invented.

The first implementation process of the present invention is used to prove that the bonding ability between the copper surface and the interface is increased, and the first implementation process is shown in Figure 5. After a copper treatment, the copper foil surface modification method (CSM-1000) is carried out. After the dry film treatment, the secondary copper treatment is carried out, then after the etching treatment, the tin stripping treatment is carried out at last, and the process flow is completed. In addition to the above process, it can also be processed after the first copper treatment. Then carry out the treatment of copper foil surface modification method (CSM-1000), and finally perform etching treatment and tin stripping treatment, and then complete the process flow; or after a copper treatment and copper foil surface modification method (CSM-1000) After the dry film treatment, the secondary copper treatment is carried out, and finally the etching treatment is carried out. It can be seen that the copper foil surface modification method of the present invention can be applied to any brand of dry film and solder resist green paint. Figure 5 shows the standard process of making PCB circuits. Using the traditional roughening line width of 2mil is the limit, and using CSM-1000 instead of traditional roughening can achieve thinner lines.

The second implementation process of the present invention proves that the present invention can be used for pre-treatment of ultra-fine line dry film. It can be seen from Figure 6 that after vacuum sputtering, the copper foil surface modification method (CSM-1000) is used, and then used Dry film treatment, followed by copper plating, nickel gold plating and etching treatment. In addition to dry film treatment, it can also be used for ultra-fine line wet film pre-treatment. And the third implementation process of the present invention is used for the pretreatment of anti-gold plating dry film, wherein Fig. 7A is the SEM photograph (100% It can be seen from the figure that after a copper treatment, a dry film photoresist (Hitachidry-film5040) is used to transfer the circuit image during the printed circuit board process, and then gold plating and etching are performed after completion; and Fig. 7B shows that the copper foil surface modification method (CSM-1000) of the present invention is introduced into the anti-electroplating gold dry film pretreatment. It can be seen from the figure that after a copper treatment, the copper foil surface modification method (CSM-1000) is carried out -1000), and then transfer the line image through dry film photoresist (Changxing dry-film115), and then perform gold plating and etching treatment. From the comparison of Figure 7A and Figure 7B, it can be seen that the situation of the two gold plating after permeation plating Significantly different. Among them, Fig. 7A Hitachi dry-film5040 refers to Hitachi's dry film model 5040, which is a special dry film to prevent seepage. Figure 7B shows the dry film model 115 produced by Changxing Company. It is a general dry film that has been treated with CSM-1000 before lamination, so no seepage occurs. Generally, the lamination needs to be roughened.

In addition, it can be seen from the comparison table in Figure 8 that the operating cost of the potion is super-coarsening micro-etching potion (1.00NTD/sf) > medium-coarsening micro-etching potion (0.75NTD/sf) > micro-etching potion (sodium persulfate SPS) (0.70NTD/sf) > micro-etching potion (sulfuric acid/hydrogen peroxide) (0.35NTD/sf) > surface modifier potion of the present invention (0.30NTD/sf), it can be seen that compared with the existing micro-etching potion Under the circumstances, the present invention can indeed save unnecessary costs.

A method for modifying the surface of copper foil used in the printed circuit board manufacturing process provided by the present invention, when compared with other prior art, has the following advantages:

(1) Since the process of the present invention does not require the use of micro-etching technology, there will be no problems of peroxide erosion of the machine and chloride ion pollution, and because it does not corrode copper, it will not cause heavy metal pollution, and there will be no waste Dealing with distress.

(2) The surface modifier used in the present invention will not change the roughness of the copper surface, and at the same time, it can effectively improve the bonding force for the ultra-thin copper process. Membrane residue and residual foot problems can be completely overcome.

(3) The present invention can improve the traditional physical super-roughening bonding ability to a chemical bonding effect, so that the overall circuit board manufacturing process is simplified and clean, and any brand of dry film and solder resist green paint is applicable. In addition, It can also save unnecessary costs.

With the help of the above detailed description of the preferred specific embodiments, it is hoped that the features and spirit of the present invention can be described more clearly, and the scope of the present invention is not limited by the preferred specific embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the claimed invention.

Claims (15)

1. A copper foil surface modification method for printed circuit board manufacturing process, characterized in that, comprising the steps: Prepare the copper foil substrate in advance, and perform surface cleaning and brushing; After brushing, degreasing treatment is carried out, and after the copper foil substrate is washed with water, the surface modifier is sprayed horizontally or soaked vertically; and Finally, after washing the copper foil substrate with water again, the copper foil substrate is dried to prepare for the subsequent process. 2. A method for modifying the surface of copper foil for printed circuit board manufacturing process as claimed in claim 1, wherein said subsequent process is a lamination process, a dry film lamination process or a solder resist coating process . 3. A method for modifying the surface of copper foil for printed circuit board manufacturing process as claimed in claim 1, characterized in that NaoH or KOH solution is used for degreasing treatment. 4. The method for modifying the surface of copper foil used in the process of printed circuit boards according to claim 1, wherein the temperature of the surface modifying agent is 20-30°C. 5 . The method for modifying the surface of copper foil used in the printed circuit board manufacturing process according to claim 1 , wherein the concentration of the surface modifying agent is 1-5% by volume. 6 . 6 . The method for modifying the surface of copper foil used in the printed circuit board manufacturing process according to claim 1 , wherein the time for horizontally spraying or vertically soaking the surface modifying agent is 30-60 seconds. 7 . The method for modifying the surface of copper foil used in the printed circuit board manufacturing process according to claim 1 , wherein the spraying pressure of the surface modifying agent is horizontally sprayed at 0.8-1.2 kg/cm ² . 8 . The method for modifying the surface of copper foil used in the printed circuit board manufacturing process according to claim 1 , wherein the temperature for drying the copper foil substrate is 85-95° C. 9. A method for modifying the copper foil surface of a printed circuit board process as claimed in claim 1, wherein the chemical formula of the surface modifying agent is (CH ₃ ) ₃ N ⁺ (M) ^- (R ₁ ), wherein R ₁ is C ₁ -C ₄₀ alkyl or benzene or phenyl; and M is F, Cl, Br, l, OH or CH ₂ COO. 10. A copper foil surface modifying method for printed circuit board manufacturing process according to claim 1, wherein the chemical formula of the surface modifying agent is (C ₆ H ₅ )(CH ₃ ) ₂ N ⁺ (M) ^- (R ₁ ), wherein R ₁ is C ₁ -C ₄₀ alkyl or benzene or phenyl; and M is F, Cl, Br, l, OH or CH ₂ COO. 11. A method for modifying the surface of copper foil for printed circuit board manufacturing process as claimed in claim 1, wherein the chemical formula of the surface modifying agent is (R ₁ )(CH ₃ ) ₂ N ⁺ (M ) ^- (R ₂ ), wherein R ₁ is C ₁ to C ₄₀ alkyl or benzene or phenyl; R ₂ is C ₁ to C ₄₀ alkyl or benzene or phenyl; and M is F, Cl, Br , l, OH or CH ₂ COO. 12. A copper foil surface modification method for printed circuit board manufacturing process as claimed in claim 1, wherein the chemical formula of the surface modification agent is (R ₁ )(C=N(CH ₂ ) ₂ )N ⁺ (M) ^- (R ₂ )OH, wherein R ₁ is C ₁ ~ C ₄₀ alkyl or benzene or phenyl; R ₂ is C ₁ ~ C ₄₀ alkyl or benzene or phenyl; and M is F, Cl, Br, l, OH or CH ₂ COO. 13. A method for modifying the surface of copper foil used in printed circuit board manufacturing as claimed in claim 1, wherein the chemical formula of the surface modifying agent is (R ₁ )(C ₅ H ₄ N)(M ) ^- (R ₂ ), wherein R ₁ is C ₁ to C ₄₀ alkyl or benzene or phenyl; R ₂ is C ₁ to C ₄₀ alkyl or benzene or phenyl; and M is F, Cl, Br , l, OH or CH ₂ COO. 14. A copper foil surface modification method for printed circuit board manufacturing process according to claim 1, wherein the chemical formula of the surface modification agent is (R ₁ )(CONH)(R ₂ )N ⁺ (CH ₃ ) ₂ (M) ^- , wherein R ₁ is C ₁ to C _{4 alkyl0} or benzene or phenyl; R ₂ is C ₁ to C ₄₀ alkyl or benzene or phenyl; and M is F , Cl, Br, l, OH or CH ₂ COO. 15. A copper foil surface modifying method for printed circuit board manufacturing process according to claim 1, wherein the chemical formula of the surface modifying agent is (R ₁ )(CONH)(R ₂ )N ⁺ (R ₃ )SO ₃ ^- , wherein R ₁ is C ₁ to C ₄₀ alkyl or benzene or phenyl; R ₂ is C ₁ to C ₄₀ alkyl or benzene or phenyl; and R ₃ is C ₁ to _C40 alkyl or benzene or phenyl.