KR101590081B1 - A surface treatment method for pcb inner layer - Google Patents

Abstract

The present invention relates to a surface treatment method for a PCB inner layer which improves contact with a prepreg by performing the surface treatment of a PCB raw material to manufacture a PCB with superior performance. The surface treatment method includes a process of dipping the PCB raw material (CCL: Copper Clad Laminate) in a solution which contains 0.1-2wt% of glycine, 0.5-2wt% of sulfuric acid, 1-5wt% of hydrogen peroxide, and 0.005-0.3wt% of copper sulfate. The PCB raw material manufactured by the surface treatment method of the PCB inner layer touches the prepreg with superior adhesion. So, the defects of the PCB can be reduced.

Description

Technical Field [0001] The present invention relates to a surface treatment method for an inner layer of a printed circuit board,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a surface treatment method for an inner layer of a printed circuit board, and more particularly to a surface treatment method for an inner layer of a printed circuit board which improves adhesion to a prepreg by surface- .

A PCB (printed circuit board) is a type of electronic component on which components are mounted and circuits for connecting the components are printed. The PCB can be divided into a PCB for mounting parts and a package substrate for semiconductor mounting.

Among electronic products, PCBs are one of the most basic and essential components, and they are very important. PCBs are a device industry that requires a lot of investment in facilities, but have the features of many processes and complex manufacturing processes.

PCB fabrication processes include (1) raw material cutting and chamfering / frontal processing for inner layer fabrication, (2) formation of inner layer circuitry through exposure-development-corrosion process, (3) (6) forming an outer layer circuit, (7) PSR printing as an insulating film, (8) finishing process, and (8) .

Due to the miniaturization and integration of parts, the demand for ultra-high-multi-layer PCBs with 40-60 layers has increased, and the process of precisely laminating and bonding each CCL having a very fine pattern has become very important.

Therefore, it is very important to improve adhesion between the PCB original plate and the prepreg in the lamination process. For this purpose, conventionally, a method of oxidizing the copper foil surface of the PCB original plate to form the roughness has been used.

Since the surface of the copper foil is oxidized by a variety of oxidizing agents such as organic acid, water, and iron oxide, the surface becomes rough due to its bulky size. Such a rough surface increases the contact area between the copper foil and the prepreg.

However, in order to improve the adhesion between the PCB original plate and the prepreg, if the roughness of the surface of the copper foil is increased to form a large number of irregularities, the current flowing path becomes longer and resistance becomes larger. If the oxidant treatment time becomes longer, The circuit resistance is increased and the performance of the printed circuit board is deteriorated.

Accordingly, there is a demand for a method of treating a surface of a PCB substrate which can firmly adhere to a prepreg without greatly increasing the roughness of the PCB original plate.

In order to solve the above-described problems, the present inventors intend to provide a surface treatment method of an inner layer of a printed circuit board which can impart good adhesion without forming an oxide film.

The present invention comprises a step of immersing a CCL (copper clad laminate) in an aqueous solution containing 0.1 to 2 wt% of glycine, 0.5 to 2 wt% of sulfuric acid, 1 to 5 wt% of hydrogen peroxide, and 0.05 to 0.3 wt% of copper sulfate 1) of the inner surface of the printed circuit board.

The aqueous solution of step 1 may further contain 0.01 to 0.5% by weight of corrosion inhibitor.

The corrosion inhibitor may be selected from the group consisting of aminophenol, benzotriazole, cysteine, thioglycerol, triazole, vanillin.

The step 1 may be treated for 30 seconds to 10 minutes.

The method may further include immersing or ultrasonically treating the surface of the PCB to clean the surface by the pretreatment step of step 1 above.

The present invention provides an inner layer of a printed circuit board manufactured according to a method of surface treatment of the inner layer of the printed circuit board.

The present invention comprises a step of immersing a CCL (copper clad laminate) in an aqueous solution containing 0.1 to 2 wt% of glycine, 0.5 to 2 wt% of sulfuric acid, 1 to 5 wt% of hydrogen peroxide, and 0.05 to 0.3 wt% of copper sulfate One); Drying the PCB original plate immersed in the aqueous solution (step 2); (Step 3) of laminating and pressing the dried original plate of the PCB with the prepreg.

In the step 1, the aqueous solution may further contain 0.01 to 0.5% by weight of a corrosion inhibitor.

The corrosion inhibitor may be selected from the group consisting of aminophenol, benzotriazole, cysteine, thioglycerol, triazole, vanillin.

The step 1 may be treated for 30 seconds to 10 minutes.

The pretreatment step of step 1 may further include immersing or ultrasonifying the original plate of the PCB for cleaning the surface.

The drying may be carried out at a temperature of 70 ° C to 150 ° C for 5 minutes to 150 minutes.

The prepreg may be an epoxy resin.

The present invention provides a printed circuit board manufactured according to the method for manufacturing a printed circuit board.

The PCB of the PCB manufactured according to the method of surface treatment of the inner layer of the printed circuit board according to the present invention can form an excellent adhesion with the prepreg, thereby reducing the defects of the printed circuit board.

The method of surface treatment of the inner layer of the printed circuit board according to the present invention can form an excellent adhesion with the prepreg without forming roughness on the PCB, thereby minimizing the resistance reduction of the printed circuit board.

Hereinafter, the present invention will be described in detail.

A method of treating a surface of an inner layer of a printed circuit board according to an embodiment of the present invention is a method of treating a surface of a printed circuit board with a CCL (Copper Clad Laminate) comprising 0.1 to 2 wt.% Of glycine, 0.5 to 2 wt.% Of sulfuric acid, 1 to 5 wt.% Of hydrogen peroxide, To 0.3% by weight of water (step 1).

Copper Clad Laminate (CCL), which is a very thin laminate coated with a base material, can be used as the base material. Epoxy, phenol, polyimide resin can be used as the base material.

In order to increase the strength of the resin, a reinforcing base material such as glass fiber or paper may be added, and a single layer resin, a multilayer resin, a composite resin in which different materials are laminated, and a resin film may be used.

As the PCB original plate, both of a cross-section type in which a copper foil is coated on only one side of the base material, and a double-side type and a multilayer type in which copper foil is coated on both sides of the base material.

In order to perform surface treatment of the inner layer of the printed circuit board according to an embodiment of the present invention, the PCB original plate is coated with 0.1 to 2 wt% of glycine, 0.5 to 2 wt% of sulfuric acid, 1 to 5 wt% of hydrogen peroxide, 0.05 to 0.3% by weight (step 1).

If the treatment time is less than 30 seconds, a new film may not be sufficiently formed on the surface of the copper foil, resulting in a problem that adhesion with the prepreg is significantly lowered. If the treatment time exceeds 10 minutes, the thickness of the formed film becomes thick, The problem of enlargement may occur.

If the content of glycine is less than 0.1% by weight, a desired reaction may not occur and a copper foil surface may not be formed. If the glycine is contained in an amount of more than 2% by weight, etching of the copper foil may occur excessively, May occur.

If the content of sulfuric acid is less than 0.5% by weight, the desired reaction may not be sufficiently carried out in the present invention, so that the surface of the copper foil may not be formed. There may arise a problem of reducing the size.

When the hydrogen peroxide is contained in an amount of less than 1% by weight, a desired reaction may not occur and a copper foil surface may not be formed. If the hydrogen peroxide is contained in an amount exceeding 5% by weight, copper oxide, which is not copper hydroxide, A problem may arise.

If the content of copper sulfate is less than 0.05 wt%, the desired reaction may not be sufficiently performed in the present invention to cause a problem that the surface of the copper foil is not formed. When the copper sulfate is contained in an amount exceeding 0.3 wt%, generation of a film And the copper foil is excessively oxidized to cause a problem that the resistance of the copper circuit becomes large.

At this time, the aqueous solution of step 1 may further include 0.01 to 0.5 wt% of corrosion inhibitor, and the corrosion inhibitor may be selected from the group consisting of aminophenol, benzotriazole, cysteine, thioglycerol, triazole, vanillin And it is most preferable to use benzotriazole.

Step 1 Copper hydroxide surface is formed on the processed PCB, and hydroxide hydroxide reacts with the hydroxyl group on prepreg (epoxy resin) to form a chemical bond. It is possible to provide a printed circuit board having more excellent performance because it is possible to provide a stronger adhesion property as compared with the frontal method in which the roughness is physically combined with the prepreg and the resistance is not reduced.

The cleaning step may further include a cleaning step for cleaning the surface of the PCB original plate by the pretreatment step of step 1, wherein the cleaning of the PCB original plate may be performed by immersion in water or ultrasonic cleaning treatment.

The present invention also provides a method of manufacturing a printed circuit board including an inner layer of a printed circuit board manufactured through the surface treatment method of the inner layer of the printed circuit board.

A method of manufacturing a printed circuit board according to an embodiment of the present invention includes the steps of applying 0.1 to 2 wt% of glycine, 0.5 to 2 wt% of sulfuric acid, 1 to 5 wt% of hydrogen peroxide, 0.05 to 0.3 wt% of copper sulfate (Copper Clad Laminate) % (Step 1); Drying the PCB original plate immersed in the aqueous solution (step 2); And a step (step 3) of laminating and pressing the dried original plate of the PCB with the prepreg.

Further, the cleaning step may further include a cleaning step for cleaning the surface of the PCB original plate by the pretreatment step of step 1, and the cleaning may be performed by immersing the PCB original plate in water or ultrasonic cleaning treatment.

The step 1 is the same as the method of surface treatment of the inner layer of the printed circuit board according to the embodiment of the present invention, and therefore, the explanation will be omitted.

If the drying temperature is less than 70 ° C or the drying time is less than 5 minutes, moisture that has not dried on the surface of the PCB original plate is left in the drying step of Step 2, preferably at 70 ° C to 150 ° C for 5 minutes to 150 minutes The adhesion to the prepreg may be lowered or the copper foil may be oxidized. If the drying temperature exceeds 150 ° C. or the drying time exceeds 150 minutes, the drying process is continued even though the drying is completed There is a problem that additional energy is consumed.

Finally, a dried PCB original plate and a prepreg are laminated and heated and pressurized to produce a printed circuit board (step 3).

In this case, the prepreg is preferably an epoxy resin. In addition, since the surface of the prepreg contains a hydroxyl group, a resin capable of forming a strong adhesive force by forming a condensation polymerization with the hydroxyl group of the surface- Any number can be used.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

≪ Comparative Example 1 &

In order to clean the copper foil with a size of 1/2 oz and 11 cm x 11 cm, it was immersed in a pH 12 alkaline cleaner solution for 4 minutes, then taken out and washed with ultrapure water.

The washed copper foil was immersed in a commercial activator (Atotech) solution for 90 seconds for primary treatment and immersed in MS-500 (Atotech) solution for 120 seconds.

The solution-treated copper foil was immersed in ultrapure water for 1 minute, washed three times, and then dried at 120 ° C for 1 hour.

The surface-oxidized copper foil was placed on a prepreg of 10 cm x 10 cm and pressed at 25 kgf / cm 2 and 220 ° C for 90 minutes using a press to bond the prepreg and the copper foil.

Peel test was used to confirm the adhesion between prepreg and copper foil.

≪ Comparative Example 2 &

In order to clean the copper foil with a size of 1/2 oz and 11 cm x 11 cm, it was immersed in a pH 12 alkaline cleaner solution for 4 minutes, then taken out and washed with ultrapure water.

The surface-cleaned copper foil was immersed in an aqueous solution prepared by adding 1 wt% of glycine and 2 wt% of hydrogen peroxide to ultrapure water for 3 minutes and then taken out and immersed in ultrapure water for 1 minute for washing.

The treated copper foil was dried at 120 ° C for 1 hour, and peel test was performed to confirm adhesion between the prepreg and the copper foil.

≪ Comparative Example 3 and Example 1-3 >

The copper foil was prepared in the same manner as in Comparative Example 2 except that the composition and the content of the aqueous solution used for the surface treatment of the copper foil were different for each of the examples.

Test conditions and adhesion measurement results Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Water content (wt%) 97 96.875 95.875 96.375 94.875 Glycine content (wt%) One One One 0.5 2 Hydrogen peroxide content (wt%) 2 2 2 2 2 Copper sulfate content (wt%) 0 0.125 0.125 0.125 0.125 Sulfuric acid content (wt%) 0 0 One One One Adhesion (gf / 25mm) 15.3 12.4 15.4 24.1 16.3 23.6

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. In addition, it is a matter of course that various modifications and variations are possible without departing from the scope of the technical idea of the present invention by anyone having ordinary skill in the art.

Claims (15)

(CCL) in an aqueous solution containing 0.1 to 2% by weight of glycine, 0.5 to 2% by weight of sulfuric acid, 1 to 5% by weight of hydrogen peroxide, 0.05 to 0.3% by weight of copper sulfate and 0.01 to 0.5% by weight of corrosion inhibitor And immersing the substrate for 30 seconds to 10 minutes.
delete The method according to claim 1,
Wherein the corrosion inhibitor is selected from the group consisting of aminophenol, benzotriazole, cysteine, thioglycerol, triazole, and vanillin.
delete The method according to claim 1,
And washing the original plate of the PCB with the pretreatment step of the above step.
A printed circuit board inner layer produced by the method of any one of claims 1, 3 and 5.
(CCL) in an aqueous solution containing 0.1 to 2% by weight of glycine, 0.5 to 2% by weight of sulfuric acid, 1 to 5% by weight of hydrogen peroxide, 0.05 to 0.3% by weight of copper sulfate and 0.01 to 0.5% by weight of corrosion inhibitor Immersing for 30 seconds to 10 minutes (step 1);
Drying the PCB original plate immersed in the aqueous solution (step 2);
(Step 3) of laminating and pressing the dried original plate of the PCB with a prepreg.
delete 8. The method of claim 7,
Wherein the corrosion inhibitor is selected from the group consisting of aminophenol, benzotriazole, cysteine, thioglycerol, triazole, and vanillin.
delete 8. The method of claim 7,
And washing the original plate of the PCB with the pretreatment step of step 1 above.
8. The method of claim 7,
Wherein the drying step is performed at 70 ° C to 150 ° C.
8. The method of claim 7,
Wherein the drying step is performed for 5 minutes to 150 minutes.
8. The method of claim 7,
Wherein the prepreg is an epoxy resin.
14. A printed circuit board manufactured by the method of any one of claims 7, 9, 11,