KR20010009433A - A method for conversion coating of printed circuit board by using acidic based conversion coating composition - Google Patents

Abstract

PURPOSE: A conversion coating forming method is provided to prevent dissolution into inorganic acids by forming an oxide film excellent in acid resistance and bonding strength on a printed circuit board. CONSTITUTION: A method of forming a conversion coating comprises the following steps: A PCB is washed. The PCB is flushed with water. The PCB is pre-dipped into a pre-dip composition for 10secs to 10mins at 10 to 60deg.C. The pre-dip composition consists of 0.1 to 5.0V% sulphuric acid, 0.1 to 10.0V% hydrogen peroxide, and at most 10wt% mixture on the volume basis of the pre-dip composition. The mixture is composed of at least one of a group including sulphur compound; and reaction accelerator and stabilizer. The PCB is dipped into a conversion coating composition for 1 to 6mins at 10 to 60deg.C. The composition consists of 0.1 to 30V% sulphuric acid, 0.1 to 15.0V% hydrogen peroxide, and at most 50wt% mixture on the volume basis of the composition. The mixture is composed of at least one of a group including sulphur compound; and film forming agent, etching rate adjusting agent, reaction accelerator and stabilizer.

Description

A method for forming a chemical coating using an acid-based chemical coating composition {A METHOD FOR CONVERSION COATING OF PRINTED CIRCUIT BOARD BY USING ACIDIC BASED CONVERSION COATING COMPOSITION}

The present invention relates to a method for processing a chemical film of a printed circuit board using an acidic based chemical film composition, and more particularly, to a method for processing a chemical film of a printed circuit board showing excellent adhesion and acid resistance.

In the manufacturing process of multilayer printed circuit board (MLB), the blackening process of inner layer circuit is adopted. The blackening process protects the inner layer circuit from the surrounding environment and combines each inner layer and outer layer (bonding sheet, prepreg). It is an indispensable process performed for the purpose of maximizing the adhesive force during the lamination process.

Until now, in the PCB industry, in order to black oxide the multilayer printed circuit board (MLB) inner layer, degreasing, washing, soft-etching, acid treatment, preliminary processing using alkaline solution as a pretreatment process before blackening is performed. -After immersion (Pre-Dip) process, using a oxidizing agent such as sodium chlorite (NaClO ₂ ) in an alkaline atmosphere of caustic soda or caustic alkali (NaOH, KOH) to copper at high temperature (70 ~ 80 ℃) A method of oxidizing the formed inner layer circuit to black has been used.

The blackening film produced by the conventional blackening process is a copper oxidized cupric oxide (CuO) layer, which is extremely weak in acid resistance, and thus is soft-etched in an acidic bath, that is, an electroless copper plating process, after blackening. , H ₂ SO ₄ / H ₂ O ₂ ), acidic copper plating solution (CuSO ₄ / H ₂ SO ₄ ) and the pink ring formed by erosion of blackening around holes drilled through the pretreatment Pinkring has caused a serious problem. In order to solve this problem, conventionally, a process of reducing a CuO (Cupric Oxide) layer to a Cu ₂ O (Cuprous Oxide) layer having excellent acid resistance is adopted. The problem of dissolving in the etching process and inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid has not been solved.

Reducing agents used in the reduction process include DMAB (Dimethyl Amine Borane), MPB (Morpholine Borane), HCHO (Formalin), NaBH ₄ (Sodium Borohydride), and KBH ₄ (Potassium Borohydride). It is a very expensive drug and accounts for most of the cost of the blackening process.

In addition, there are some blackening processes that are carried out at acidic sites. However, they are extremely sensitive to chlorine ion concentration in the bath, which makes them difficult to manage. Its reliability is less than 1kg / ㎠. Is vulnerable.

Accordingly, an object of the present invention is to solve the problems of the conventional alkali blackening process to provide a method for forming a chemical conversion film of a printed circuit board to form a brown oxide film having excellent acid resistance and adhesive strength on the printed circuit board.

Another object of the present invention is to provide a method for forming a chemical conversion film of a printed circuit board, which does not require the pretreatment and posttreatment processes required for the conventional blackening treatment process, thereby significantly reducing process lines and process costs.

In Figure 1 (a) is a conventional blackening method (b) is a view showing the chemical conversion coating process according to the present invention,

Figure 2 is a substrate photograph showing the results on the chemical resistance of the coating film formed by the method according to the present invention,

3A to 3J are photographs showing the surface state of a printed board processed according to the chemical conversion film treatment method of the present invention in Example 6. FIG.

According to the invention,

I. Washing the printed circuit board;

II. Washing with water;

III. Based on the total volume of the preliminary composition, (1) 0.1 to 5.0 v% sulfuric acid; (2) 0.1 to 10.0 v% hydrogen peroxide; and (3) 10 wt% or less of a mixture of sulfur compounds, reaction accelerators, and at least one component during stabilization. Pre-dipping the printed circuit board into the composition at 10 to 60 ° C. for 1 to 10 minutes;

Ⅳ. (1) 0.1-30 v% sulfuric acid (2) 0.1-15 v% hydrogen peroxide, and (3) a mixture of sulfur compounds and at least one component of the film-forming aid, etching rate regulator, reaction accelerator and stabilizer based on the total volume of the chemical composition. Applying a printed circuit board to the chemical film composition composed of 50 wt% or less at 10 to 60 ° C. for 1 to 10 minutes to process the chemical film;

Ⅴ. Washing with water; And

Ⅵ. Drying;

Provided is a method for forming a chemical film of a printed circuit board.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the method for forming a chemical film according to the present invention, a process is shortened by forming a chemical film on a printed circuit board using an acidic basic chemical film composition, and a black-brown oxide film having excellent acid resistance and adhesion resistance on the printed circuit board is formed.

In the method for forming a chemical film of the present invention, first, a printed circuit board to be formed on the chemical film is degreased (washed). Degreasing is usually performed when forming a chemical film, and the residue, foreign matter, fingerprints, etc. of the previous process (D / F) are removed from the substrate. Wash with water after that. After washing with water, the printed circuit board is pre-dipped in the pre-deposited composition.

The pre-deposition is composed of a composition similar to that of the chemical film composition before the chemical film treatment, and the concentration is a copper surface suitable for the chemical film forming process by pre-immersing the printed circuit board in a pre-deposit composition having a lower concentration than the chemical film composition. By activating, the initial reaction of the coating is accelerated and the conditions for forming a uniform film are prepared. The pre-deposition process functions as washing, conditioning, catalyst and activation.

The pre-deposition composition used in the pre-deposition process is composed of at least one component of sulfuric acid, hydrogen peroxide, organic acids, nitrogen compounds and silicon compounds, and reaction accelerators and stabilizers.

Sulfuric acid in the pre-deposited composition is 0.1 to 5.0 v%, preferably 0.1 to 1.0 v% based on the volume of the pre-deposited composition and hydrogen peroxide is 0.1 to 10.0 v%, preferably based on the volume of the pre-deposited composition It is used at 0.1 to 5.0 v%. If sulfuric acid and hydrogen peroxide are used at less than 0.1v%, the intended effect is not exhibited. If sulfuric acid is used at 5.0v% or hydrogen peroxide of 10.0v% or more, copper is etched during pre-deposition, which is undesirable.

The sulfur compound is used in an amount of 10 wt% or less based on the total volume of the pre-deposited composition as a mixture by mixing at least one component of the reaction accelerator and stabilizer with the composition range within each composition ratio described below. That is, it is preferable that the mixture is used at a concentration level of about 5/1 of the chemical conversion composition concentration so as to most appropriately achieve the intended effect of pre-deposition.

Pre-deposition is carried out for 10 seconds to 10 minutes at a temperature of about 10-60 ° C. to the pre-deposition composition having the composition as described above. Pre-deposition is a process that activates the copper surface to speed up the initial coating reaction. If it is not pre-deposited, the reaction rate is delayed only when forming the chemical film.

After pre-deposition as described above, washing with water can be optionally performed, and washing with water is preferred. In the case of the pre-deposition or washing with water, after washing with water, a chemical film composition is applied to a printed circuit board to form a chemical film.

The chemical composition is composed of (1) sulfuric acid, (2) hydrogen peroxide, (3) sulfur compounds and (4) film forming aids, etching rate regulators, reaction promoters, and stabilizers. The sulfuric acid and hydrogen peroxide in the composition are used to etch copper while maintaining the acidity of the composition, and the etching action is used as a driving force to form a black-brown oxide film as the sulfur compound is colored on the metal copper surface.

At this time, the inorganic and organic acids including sulfuric acid and hydrogen peroxide have a secondary function of increasing the cohesion of the resulting coating film, increasing the adhesion and assisting the color of the coating film.

Sulfuric acid is used in the chemical composition as 0.1-30v%, preferably 1.0-15v% based on the volume of the chemical composition. If the amount of sulfuric acid is less than 0.1 v%, it is difficult to form a film. If the amount of sulfuric acid is 30 v% or more, the structure of the film is not formed densely.

Hydrogen peroxide is used in an amount of 0.1 to 15 v%, preferably 1.0 to 10 v%, based on the volume of the chemical composition. If the amount of hydrogen peroxide is less than 0.1 v%, it is difficult to form a film. If the amount of hydrogen peroxide is more than 15 v%, the etching ability of copper is excessively activated, resulting in an uneven film and a risk of re-dissolution.

The sulfur compound is used in an amount of 50wt% or less based on the volume of the chemical conversion composition as a mixture by mixing at least one component of the film forming aid, the etching rate control agent, the reaction accelerator and the stabilizer in a composition within the following composition ratio.

That is, in the case of mixing the sulfur compound and other additives for use in the pre-deposited composition and the chemical conversion composition, each component is mixed in the following ratio.

The sulfur compound used in the pre-deposition composition and the chemical conversion composition is used in an amount of 0.1 to 30 wt%, preferably 0.1 to 20 wt%, more preferably 0.5 to 15 wt%, based on the total volume of the coating composition. If it is less than 0.1wt%, the coating layer is formed too thin. If it is more than 30wt%, the coating layer becomes thick and the degree of curing of the coating is excessively increased, thereby decreasing adhesion.

Inorganic sulfur compounds and organic sulfur compounds may be used as sulfur compounds, and the inorganic sulfur compounds used may be ammonium salts ((NH ₄ ) ₂ S, etc.) or alkali metal salts (Na ₂ S, K ₂ S), and organic sulfur compounds as organic sulfur compounds. Examples thereof include sulfur such as sulfo sulfonate, thiocyanate, thiosulfate, thiourea and derivatives thereof, thiophosphoric acid and its salts, thioglycolic acid and its salts, thio compounds and mercapto compounds Any kind of organic compound containing is used.

On the other hand, -S- or -SS-, -SSS-, RS-, R-SH, R = S, RS- (wherein R is carbon, hydrocarbon, or nitrogen and radicals or compounds containing them) and the like. Sulfur compounds containing the same active sulfur are more preferred, and it is more preferable to contain nitrogen in the sulfur compounds.

The coating composition according to the present invention contains at least one of the following additives in order to increase the reactivity and reliability in addition to the above compounds.

As an additive, the film forming auxiliary agent is added to form a uniform colored film, such as hydroquinone, resorcinol, pyrocatehol, pyrogalol and its derivatives, 1H benzotriazole , Tolytriazole, benzothiazole, imidazole and derivatives thereof may be used.

The film forming aid is used in an amount of 0.1-20 wt%, preferably 0.1-15 wt%, more preferably 0.5-10 wt%, based on the volume of the coating composition. If the amount is less than 0.1wt%, the effect is insignificant, and if it is more than 20wt%, the film forming reaction is disturbed or the bond strength of the film is lowered.

Etch rate modifiers are additives to control the etching rate of copper, which is the driving force for the coating reaction. N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 2-pyrrolidone, dimethyl Polar solvents selected from the group consisting of formamide, dimethyl acetamide, tetrahydrofuran, acetonitrile, dioxane, alkyl lactate, alkyl glycolate, alkyl phosphate, ketones and alcohols are used alone or in combination.

The etch rate modifier is used in the range of 0.1-30 wt%, preferably 0.1-20 wt%, more preferably 0.5-10 wt%, based on the volume of the coating composition. If it is used below 0.1 wt%, it does not affect the etching rate. If it is used above 30wt%, the solubility of copper etched is significantly reduced.

Reaction accelerators are added to pre-deposition compositions and / or chemical conversion compositions to aid in the promotion of reactions and the formation of coatings. Ryu; Chlorides including chlorate and hydrochloric acid such as NaClO ₃ , KClO ₃ , NH ₄ Cl, FeCl ₃ , CuCl ₂ ; Nitrates or nitrates such as sodium nitrate, potassium nitrate, ammonium nitrate; Phosphoric acid or phosphate salts; Trivalent iron salts such as iron nitrate, iron sulfate and iron citrate; It is selected from the group consisting of.

The reaction accelerator is used in the range of 0.1-20 wt%, preferably 0.1-15 wt%, more preferably 0.5-10 wt%, based on the volume of the coating composition. If it is used at less than 0.1 wt%, reaction promoting effect is insignificant. If it is used at more than 20 wt%, the film color is blurred overall and it is difficult to obtain uniform color.

Stabilizers are used in pre-deposition compositions and / or chemical conversion compositions, and chelating agents such as Nitrilo Triacetic Acid (NTA) and its metal salts, EDTA and its metal salts, DPTA and its metal salts, and the like.

The stabilizer is used in the coating composition in an amount of 0.1-20 g / l, preferably 1-5 g / l, based on its total volume. If it is used below 0.1 g / l, the protection of hydrogen peroxide is insignificant. If it is used above 20 g / l, the copper etching rate is significantly reduced.

The chemical film forming step is performed for about 1 to 6 minutes, preferably 2 to 5 minutes at a temperature of about 10 to 60 ℃, preferably 30 to 50 ℃, where the chemical film is sprayed on the printed circuit board composition Or by dipping the printed circuit board into the composition. Below 10 ° C, the adhesion of the chemical film is poor, and above 60 ° C, the peel strength decreases.

The coating composition of the present invention is a substrate after washing and washing the inner layer substrate without the need to go through the soft-etching, acid treatment, reduction process conventionally performed in the blackening process of the multilayer printed circuit board (MLB) substrate When applied to, a black-brown film is formed in the copper (Cu) circuit to give acid resistance and lamination.

After conversion coating the printed circuit board with the conversion coating composition as described above, the conversion coating process of the printed circuit board is completed by washing with water and drying.

Water washing is performed by three steps of water washing, and one step is performed by hot-rinse.

Drying is sufficiently dried at a temperature of about 110 ° C. for about 30 minutes so that moisture or air remains on the substrate so that the substrate does not act as a defect of inflating the substrate such as laminate voids.

Such a chemical coating treatment method is applied to the surface treatment of a substrate, the adhesion of a laser drill, a roll coater, a dry film, and the increase of the adhesive force of a printed circuit ink or a thermosetting ink.

Hereinafter, embodiments of the present invention will be described in detail.

Example

In each of the following examples, degreased and washed with HD 250 ™ at 50 ° C. for 3 minutes, and then pre-deposited copper foil and laminated core specimens (20 × 30 cm) were subjected to pre-deposition at 25 ° C. for 1 minute. Applying to each composition of Table 1-1 to Table 3-1 was subjected to the chemical conversion coating of the printed circuit board and the results are shown in Table 1-2 to 3-2.

Preliminary immersion compositions used throughout this Example were prepared by mixing 30 ml / l of hydrogen peroxide, 5 ml / l of sulfuric acid, 1 g / l of phosphoric acid, 0.1 g / l of acetic acid, and 25 g / l of 2-mercapto pyridine.

After the conversion coating, it was washed with water, and the copper foil and the laminate coil were dried at 100 ° C. for 30 minutes, and then laminated under the following conditions.

<Lamination condition>

2 pieces of prepreg 1080 (140 ℃ Tg of multifunctional epoxy resin)

Pressure 30 kg / ㎠

Temperature 185 ℃

170 minutes

On the other hand, after coating coating the coating composition on the copper foil and laminate core specimens, the appearance, adhesive strength and thermal shock of the printed circuit board were measured.

The appearance of the printed circuit board was visually observed.

The adhesive strength is formed by laminating a copper foil coated according to JIS standard C 6481 with one inner layer (CCL disc) and two upper and lower sheets of prepreg 1080, attaching a tape 1cm wide to the molding, and then removing the copper foil. As a reference, the specimens having the width of 1 cm left and right were cut out to prepare a 3 cm long specimen, and after removing the tape, the copper foil was peeled off about 90 cm (to a right angle) about 4 cm and measured by a tensile strength meter.

The thermal shock test was performed for 20 seconds (1 cycle, 260 ° C; JIS C6481 5.5) for the laminated specimen and the finished circuit board in 260 ° C and 288 ° C baths in which lead (Pb) was dissolved according to MIL and JIS standards. And immersion for 10 seconds (1 cycle, 288 ° C; MIL-S-13949H), followed by microsection to observe the presence or absence of delamination lifting and laminate voids.

Example 1

In this example, the formation of the brown oxide film according to the conversion coating temperature was measured.

After preparing the conversion coating composition of Table 1, degreased and pre-soaked copper foil and laminate core specimen as described above to the coating composition while changing the temperature of the coating composition to 25 ℃, 30 ℃, 35 ℃ and 40 ℃ It was immersed for 3 minutes to convert coating. At this time, the composition was stirred at a speed of about 0.1 m / sec.

Chemical Coating Composition ingredient Composition Sulfuric acid (98%) Hydrogen peroxide (35%) N-methyl-2-pyrrolidonetetrahydro furanpyrocateol1-propanesulfonic acid 3- [ethoxy-thiooxomethyl) -thio]-potassium salt DPTA-5Na 50 ml / l45ml / l40ml / l 20ml / l30 g / l60 g / l2 g / l

Item 25 ℃ 30 ℃ 35 ℃ 40 ℃ Exterior Dark brown Dark brown maroon maroon Adhesive strength 1.0 kg / ㎠ 1.1 kg / ㎠ 1.3 kg / ㎠ 1.4 kg / ㎠ Thermal shock Uplifting none none none none damaged none none none none

As can be seen in Table 1b, by converting coating within a temperature range of 30 to 50 ℃ brown oxide film having a sufficient adhesive strength was formed and there was no delamination lift and laminate damage.

Example 2

In this example, the formation of the brown oxide film according to the change of the conversion coating time was measured.

To prepare a coating composition of the following Table 2a and then pre-treatment as described in the above Examples and the coating time was changed to 1 minute, 2 minutes, 3 minutes 4 minutes to form a chemical coating on the specimen and the results are shown in Table 2b Indicated. At this time, the chemical conversion coating temperature was 35 ° C., and the coating composition was stirred at a speed of about 0.1 m / sec.

Chemical Coating Composition ingredient Composition Sulfuric acid (98%) Hydrogen peroxide (35%) 2-Pyrrolidoneacetonitrile 1 H benzo triazole 1-propane sulfonic acid 3-[(dimethylamino) -thiooxomethyl) -thio sodium chlorine metasilicate 50ml / l40ml / l50ml / l 30ml / l 40 g / l80 g / l 1.5 g / l

Item 1 minute 2 mins 3 mins 4 mins Exterior Dark brown maroon maroon maroon Adhesive strength 0.8 kg / ㎠ 1.1 kg / ㎠ 1.3 kg / ㎠ 1.4 kg / ㎠ Thermal shock Uplifting none none none none damaged none none none none

As can be seen from the results of Table 2b, a brown oxide film having sufficient adhesive strength was formed by chemical conversion coating for 2 to 5 minutes, and there was no lamination lift and laminate voids.

Example 3

In this embodiment, the formation of the brown oxide film according to the stirring speed of the chemical conversion composition was measured.

To prepare a coating composition of the following Table 3 and then pre-treatment as described in the above Example and the chemical conversion coating while changing the stirring conditions to stagnation, 0.1 m / s and 0.2 m / s and the results are shown in Table 3-2 It was. At this time, the chemical conversion treatment was performed by immersion at 35 ° C for 3 minutes.

Chemical film composition ingredient Composition Sulfuric acid (98%) Hydrogen peroxide (35%) Dimethylformamide Ethyl lactate pyrogarol 2-mercapto pyridinenitrile sodium triacetate 45 ml / l40 ml / l30 ml / l30 ml / l50 g / l120 g / l1.0 g / l

Item Identity Stirring (0.1m / s) Stirring (0.2m / s) Exterior maroon maroon maroon Adhesive strength 1.3 kg / ㎠ 1.3 kg / ㎠ 1.2kg / ㎠ Thermal shock Uplifting none none none damaged none none none

As can be seen from the results of Table 3b, by coating with a conversion coating method according to the present invention, a brown oxide film having sufficient strength was formed, and lamination lifting and lining damage were not formed.

Example 4

In this embodiment, the adhesive strength of the multilayer printed circuit board manufactured by forming the chemical film by the method according to the present invention was measured 16 times.

Pretreatment and adhesive strength were measured by the method described in the above examples.

The preliminary deposition composition is described in the examples and the chemical composition was used in the composition of Example 3. Preliminary deposition was performed for 1 minute at the temperature of 20-30 degreeC, and chemical conversion treatment was performed for 40 minutes at 40 degreeC.

In the case of blackening treatment using conventionally used DMAB and MB, the substrate was treated according to the conventional blackening treatment process, and the test results are shown in Table 4 below.

division Chemical coating treatment 3 minutes Conventional Medication (DMAB) Legacy Drugs (MB) Thickness of copper foil 35 μm 35 μm 35 μm One 1.35 1.20 1.20 2 1.35 1.24 1.14 3 1.27 1.09 1.15 4 1.32 1.24 1.18 5 1.27 0.98 1.00 6 1.39 1.27 1.12 7 1.24 1.13 1.10 8 1.25 1.02 1.14 9 1.24 1.31 1.12 10 1.29 1.04 1.10 11 1.37 1.05 1.23 12 1.10 1.10 13 0.99 1.16 14 1.24 1.22 15 1.03 1.18 16 1.05 1.15 Max 1.37 1.27 1.23 Min 1.24 0.98 1.00 Average 1.304 1.124 1.143

As can be seen in Table 4-2, when forming a chemical film by the method of the present invention, the adhesive strength was improved.

Example 5

In the present embodiment was measured for the heat resistance (chemical resistance) of the oxide film formed after the conversion coating by the method according to the present invention and the results are shown in FIG.

Pre-deposition was carried out for 1 minute at a temperature of 20 ~ 30 ℃ using the composition described in the above Example, and the chemical film treatment was used for the chemical film composition of Example 3, the treatment time is 3 minutes, 3 minutes 30 seconds, The coating film was coated at 4 and 5 minutes and the treatment temperature was changed to 24 ° C, 28 ° C and 32 ° C.

Thus, the printed circuit board on which the chemical conversion film was formed was immersed in the copper copper, the neutralization tank, 98% sulfuric acid, and 35% hydrochloric acid for 1 hour.

As can be seen in Figure 2 the brown oxide film formed by the method according to the present invention exhibited excellent chemical resistance that does not damage the oxide film even when deposited in 98% sulfuric acid or 35% hydrochloric acid.

Example 6

In this embodiment, pre-deposition was performed for 1 minute at a temperature of 20 to 30 ° C. using the composition described in the above example, and the chemical conversion treatment was performed using the chemical conversion composition of Example 3, and the treatment time was 2 at a time. In 2 minutes, 2 minutes 30 seconds, 3 minutes and 4 minutes, 2 times, 2 minutes 30 seconds, 3 minutes, 3 minutes 30 seconds, 4 minutes and 5 minutes were subjected to chemical coating at 40 ° C. The composition was not stirred in one test and the composition was stirred at 1 m / s in two tests.

The test results are shown in FIGS. 3A to 3J, and when the chemical conversion film was formed by the method of the present invention, the printed circuit board showed excellent roughness.

Example 7

For each of the following items, an environmental test of a printed circuit board manufactured by the chemical conversion film forming method according to the present invention was conducted.

In this example, 5% 250 ™ was used to wash for 3 to 5 minutes at 50 ° C, preliminary immersion at 40 to 50 ° C for 1 minute, and chemical conversion treatment at 40 ° C for 3 minutes. In addition, the process was performed as described in the said Example, and the prepositioned composition used the composition of Example 3 for the chemical conversion film composition for the Example, respectively.

In accordance with the JIS test standards, thermal stress-solder, air to air thermal cycle, liquid to liquid thermal shock, and high temp. And humidity test were performed. , And exhibited good characteristics of passing the physical properties required by the JIS test standard.

By coating the composition on the printed circuit board by the method of forming a chemical film according to the present invention, a black-brown oxide film having excellent acid resistance and adhesive strength is formed, and furthermore, the reduction treatment process is shortened and the use of expensive reducing treatment chemicals conventionally used is excluded. The process cost is reduced.

Claims (18)

I. Washing the printed circuit board; II. Washing with water; III. (1) 0.1 to 5.0 v% sulfuric acid, (2) 0.1 to 10.0 v% hydrogen peroxide, and (3) 10 wt% or less of a mixture of sulfur compounds, reaction accelerators and at least one component during stabilization. Pre-dipping the printed circuit board at 10 to 60 ° C. for 10 seconds to 10 minutes; Ⅳ. (1) 0.1-30 v% sulfuric acid (2) 0.1-15 v% hydrogen peroxide and (3) at least one component of sulfur and silicon compounds, film forming aids, etching rate regulators, reaction promoters and stabilizers, based on the volume of the chemical composition. Applying a printed circuit board to the chemical film composition composed of 50 wt% or less of the mixture at 1 to 10 minutes at 10 to 60 ° C. for chemical film treatment; Ⅴ. Washing with water; And Ⅵ. Drying; Method of forming a conversion coating consisting of. The method of claim 1, further comprising washing with water after the pre-immersion step. The method for forming a chemical film according to claim 1, wherein the chemical film treatment is performed at 30 to 50 ° C for 2 to 5 minutes. The method of claim 1, wherein the chemical composition comprises 0.1-30 wt% of the sulfur compound based on the volume of the chemical composition. The method of claim 4, wherein the chemical composition comprises 0.1-20 wt% of the sulfur compound based on the volume of the chemical composition. 6. The method of claim 5, wherein the chemical composition comprises 0.5-15 wt% of the sulfur compound based on the volume of the chemical composition. The method according to any one of claims 1 to 3, wherein the film forming auxiliary agent is used in an amount of 0.1-20 wt% based on the volume of the chemical composition. The method of claim 7, wherein the film forming aid is used in an amount of 0.1-15 wt% based on the volume of the chemical composition. The method of claim 1, wherein the etching rate control agent is used in an amount of 0.1-30 wt% based on the volume of the chemical conversion composition. 10. The method of claim 9, wherein the etching rate control agent is used at 0.1-20 wt% based on the volume of the chemical composition. The method of claim 1, wherein the reaction accelerator is used in an amount of 0.1-20 wt% based on the volume of the chemical composition. The method of claim 11, wherein the reaction accelerator is used in an amount of 0.1-15 wt% based on the volume of the chemical composition. The method according to any one of claims 1 to 3, wherein the stabilizer is used at 0.1-20 g / l based on the volume of the chemical conversion composition. The sulfur compound according to any one of claims 1 to 3, wherein the sulfur compound is an inorganic sulfur compound such as an ammonium salt and an alkali metal salt of a sulfur compound; Sulfo Sulfonate, Thiocyanate salts, Thiourea and its derivatives, Thiophosphoric acid and its salts, Thioglycolic acid and its salts, Thiosulfate and Sulfonate A compound comprising a thio compound such as a compound) and an organic sulfur compound such as a mercapto compound. The method of claim 7, wherein the encapsulation aid is Hydro Quinone, Resorcinol, Pyrocatehol, Pyrogalol and its derivatives, 1H benzotriazole, Tolytria A method of forming a chemical conversion film, characterized in that it is selected from the group consisting of sol, benzothiazole, imidazole and derivatives thereof. The method of claim 9, wherein the etching rate control agent is N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 2-pyrrolidone, dimethylformamide, dimethyl acetamide, tetrahydrofuran, A method of forming a chemical conversion film, characterized in that it is selected from the group consisting of polar solvents such as acetonitrile, dioxane, alkyl lactate, alkyl glycolate, alkyl phosphate, ketones and alcohols. The method of claim 11, wherein the reaction promoter is ammonium, sodium, potassium peroxalate and Monosulfates such as persulfates, sodium and potassium peroxy monosulfate; Chlorides including chlorate and hydrochloric acid such as NaClO ₃ , KClO ₃ , NH ₄ Cl, FeCl ₃ , CuCl ₂ ; Nitrates or nitrates such as sodium nitrate, potassium nitrate, ammonium nitrate; Phosphoric acid or phosphate salts; A method of forming a chemical conversion film, characterized in that it is selected from the group consisting of trivalent iron salts such as iron nitrate, iron sulfate, iron citrate. The method of claim 13, wherein the stabilizing agent is selected from the group consisting of chelating agents such as Nitrilo Tricetic Acid (NTA) and its metal salts, EDTA and its metal salts, DPTA and its metal salts, and the like.