KR20070025643A - Acid copper electroplating composition and process for plating through holes in printed circuit boards - Google Patents

Abstract

An acid copper electroplating composition or additive for plating through holes, which obtains a coating film with superior physical properties formed on surfaces of printed circuit boards, and forms through holes with excellent throwing power formed in the printed circuit boards, and a plating method using the same are provided. As a composition for a copper electroplating solution comprising an acid, a copper salt, a chlorine ion, a cysteine derivative sulfur compound, a water-soluble mercapto organic brightener, a carrier, a wetting agent, a levelling agent and a refining agent, the composition comprises: at least one compound selected from the group consisting of a cysteine derivative sulfur compound and a water-soluble mercapto organic brightener; and at least one compound selected from 0.001 to 2.0 g of N-ethylcysteine, 0.001 to 2.0 g of N-propylcysteine, 0.001 to 3.0 g of N-isopropylcysteine, 0.001 to 3.0 g of N-isobutylcysteine, 0.002 to 2.0 g of N-cyclohexylcysteine, 0.001 to 2.0 g of N-(cyclohexylmethyl)cysteine, 0.001 to 1.0 g of S-(tert-butylthio)cysteine, and 0.001 to 1.0 g of N-dithiocarboxylic acid based on 1 liter of the copper electroplating solution.

Description

Acid copper electroplating composition and process for plating through holes in printed circuit boards}

The present invention relates to a composition of an acidic electrolytic solution for through hole plating of a printed circuit board (PCB) and a plating method using the same. More specifically, as an additive used in plating acidic coins, the composition of acidic solutions for PCB through hole plating has excellent coating properties and excellent electrodeposition properties of PCB surface and through holes through the composition of coins solution containing cysteine derivative material. And it relates to a plating method using the same.

Recently, various digital-related industries such as mobile communication terminals, semiconductors, computers, etc. have brought rapid technological expansion and quantitative advancement. For this purpose, high density and multilayered printed circuit boards are required. This high density interconnection (HDI) PCB has a limitation in that it is difficult to cope with technological advances by using a conventional multi-layer board (MLB) process, which simply makes and compresses multiple layers of PCB.

As the large-scale integrated technology of printed circuit boards is rapidly developed, the overall performance improvement such as the response speed of the circuit that can cope with this is required, and it is an electrical connection material that meets this and secures the reliability of the product. Phosphorus copper is commonly used. In addition, copper-coated through-hole plating technology has been widely used due to the recent trend of high speed, high integration, and high capacity, which makes wiring more dense and has excellent connection reliability. However, when plating through-holes using coin-coating compositions and additives used in conventional coin-sealing technology, the uniform electrodeposition inside the holes is reduced, and in order to secure product reliability and minimize the defective rate, it is 0.05 A / dm 2 or less. It has a disadvantage of taking a long time at low current, so it is difficult to apply in actual production sites, and there is a problem of low efficiency due to the large difference in plating thickness between PCB surface and inside of hole. In addition, when plated with high current to increase the precipitation inside the hole, the film property on the PCB surface is degraded due to the rapid growth of copper and the excessive precipitation of copper, and the uniform electrodeposition of the inside of the hole is lowered, thus ensuring the reliability and completeness of the product. There is no problem.

The present invention is to solve the conventional problems as described above, the composition and additives of the acidic anti-corrosive solution for through-hole plating and excellent plating properties of the PCB surface and excellent electrodeposition of the PCB surface and through-holes and plating method using the same The purpose is to provide.

The present invention acts as an important factor in filling the inside of the hole during plating by mercapto-containing organic brightener, carrier and wetting agent, leveler, which are the compositions of conventional acidic anticoagulants. Based on the chemicals corresponding to each composition, extensive research was carried out, and the life of the bath was long and the gloss and film properties were excellent when the coin plating for through-hole plating was carried out in the composition of a specific compound including cysteine derivative material. In particular, since the electrodepositing property of the PCB surface and the through hole is very excellent, the problem occurring in the conventional acidic solution is solved.

The composition of the acidic anticorrosive solution of the present invention, which achieves the above object, includes at least one water-soluble mercapto-containing organic brightener, a carrier and a wetting agent, and a multicharged nitrogen-containing organic compound in a coin solution containing acid, copper salt and chlorine ion. It consists of the addition of the leveling agent, the micronizing agent and the stabilizing agent.

Acid is sulfuric acid, which is required for electrolytic conductivity as electrolyte. The higher the sulfuric acid concentration is, the lower the current density is, the better the electrical conductivity is. The use range of sulfuric acid is preferably 50 ml to 200 ml, more preferably 65 ml to 120 ml, based on 1 liter of the coin solution according to the present invention.

Copper salts are copper sulfate pentahydrate used as a source of copper ions. High concentrations lead to copper sulfate crystallization at the anode during copper plating, resulting in poor electrodeposition. The use range of the copper sulfate pentahydrate on the basis of 1 liter of the coin solution according to the present invention is 50 g to 200 g, more preferably 60 g to 110 g.

Chlorine ions are used from sodium chloride and hydrochloric acid as materials which greatly affect the quality of plating. When the concentration of chlorine ions is high, a passivation film is formed on the anode, thereby degrading anode dissolution and conduction, and when insufficient, precipitation stain occurs. The preferable use range of chlorine ion by this invention is 5 ppm-120 ppm, More preferably, it is 10 ppm-80 ppm.

The water-soluble mercapto organic brightener has the function of promoting the deposition reaction, miniaturizes the precipitated particles and imparts gloss and flexibility to the plating film. When added at a high concentration, the electrodepositability inside the hole is poor, and when added at a low concentration, the PCB surface is very rough. Since the concentration of the polish is consumed during the plating process, it is accompanied by a constant amount of regular addition. The amount of the polish is added easily by the cyclic voltammogram stripping (CVS) method. Effective cysteine derivatives according to the present invention, based on the type of sulfur compound and water-soluble mercapto organic brightener and 1 liter of coin solution, the preferred range of use is N-ethylcysteine 0.001g to 2.0g, N-propylcysteine 0.001g to 2.0g, N -Isopropyl cysteine 0.001 g to 3.0 g, N-isobutyl cysteine 0.001 g to 3.0 g, N-cyclohexylsteine 0.002 g to 2.0 g, N- (cyclohexylmethyl) cysteine 0.001 g to 2.0 g, S- ( Tert-butylthio) cysteine 0.001g-1.0g, cysteine N-carbodithioic acid 0.001g-1.0g, used alone or in combination, N, N-dimethyl-dithiocarbamyl propyl sulfonic acid 0.001g-1.0g, 0.001 g to 1.0 g of bis- (sodium sulfopropyl) -disulfide, alone or in combination, are used together with cysteine derivative sulfur compounds. Among the above-mentioned water-soluble mercapto organic brighteners, the cysteine derivative water-soluble mercapto organic brighteners synthesized using cysteine as a starting material are N-alkyl (C1-C5), N-dialkyl (C1-C5), and N-isoalkyl (C1). -C5), derivatives containing N-cycloalkyl (C3-C8).

Carriers and wetting agents form monomolecular films on the cathode interface as they interact with chlorine ions and broadly inhibit copper precipitation. When added at a high concentration, the growth rate of the plated particles is very slow. When added at a low concentration, the surface of the plating is rough and the film properties are degraded. When used in combination according to the composition and concentration of the varnish, the gloss and film properties are good and uniform plating of the inside of the hole and the PCB surface is possible. Effective carriers and wetting agents according to the invention are 0.01 g to 0.5 g of cross-linked polyamide (Mn = 4,000 to 40,000), 0.01 g to 2.0 g of polyvinylpyrrolidone (Mn = 10,000 to 55,000), poly 0.001 g to 2.0 g of vinyl alcohol (Mn = 9,000 to 200,000), 0.01 g to 5.0 g of polyethylene glycol (Mn = 400 to 45,000), 0.001 g to 0.1 g of polyalkyl beta-naphthol (Mn = 10,000 to 100,000), alone or Used in combination.

The leveling agent and the micronizing agent increase the uniform electrodeposition property on the surface of the irregular plating material and inside the through hole, impart the smoothness of the plating film and improve the gloss. When used in high concentration, the surface of PCB may be stained or unplated, that is, unplated. If used less, uniform electrodeposition and smoothness of PCB surface are reduced. Effective leveling agent and micronizing agent according to the present invention is acetamide 0.01g ~ 1.0g. 0.01 g to 1.0 g of sulfanylamide, 0.01 g to 1.0 g of diallylamine, 0.001 g to 0.01 g of 4-toluenesulfonamide, 0.001 g to 0.3 g of cetyltrimethylammonium chloride, (3-chloro-2-hydroxypropyl) Trimethylammonium chloride 0.001g to 0.3g, octyltrimethylammonium chloride 0.001g to 0.3g, poly (diallyldimethylammonium chloride) 0.01g to 0.5g, benzyldimethyl (2-hydroxyethyl) ammonium chloride 0.001g to 0.3g Used alone or in combination.

In the plating method of the composition of the acidic anti-corrosive solution for PCB through-hole plating of the present invention described above, a current range of 1.0 A / dm 2 to 4.0 A / dm 2 is used after the material to be coated is immersed in the solution. In addition, by plating in the gentle range of 20 ℃ ~ 27 ℃, the long life of the bath is secured and the gloss and film properties are excellent. Especially, the plating is possible to have the excellent electrodeposition property of PCB surface and through hole. It was.

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the present invention to the specific forms of the examples but including obvious forms and modifications.

<Example 1>

A 1 liter standard coin-coated solution containing the following components was prepared, and the anode was made of 0.03% to 0.06% copper-containing soluble anode, and the current density of 2.0 A / dm 2 and the experimental conditions of room temperature (25 ° C.) were established. After the coin plating, the plated state and the surface state of the material to be plated were confirmed.

ingredient content Copper Sulfate Pentahydrate 75 g / L Sulfuric acid 95 ml / L Chlorine Ion 40 ppm N-cyclohexestein 0.01 g / L S- (tert-butylthio) cysteine 0.001 g / L Bis- (sodium sulfopropyl) -disulfide 0.01 g / L Poly (diallyldimethylammonium chloride) 0.1 g / L Polyvinyl alcohol 0.1 g / L

Coin plating was carried out in the composition as described above to form a plating excellent in the gloss and film properties of the PCB surface and excellent electrodeposition uniformity.

<Example 2>

After the coin plating solution containing the following components were prepared on the basis of 1 liter, the experimental conditions were performed in the same manner as in Example 1, and then the plated state and the surface state of the plated material inside the printed circuit board hole were confirmed.

ingredient content Copper Sulfate Pentahydrate 75 g / L Sulfuric acid 95 ml / L Chlorine Ion 40 ppm N-cyclohexestein 0.005 g / L N, N-dimethyl-dithiocarbamyl propyl sulfonic acid 0.01 g / L Poly (diallyldimethylammonium chloride) 0.1 g / L Acetamide 0.03 g / L

Coin plating was carried out in the composition as described above to form a plating excellent in the gloss and film properties of the PCB surface and excellent electrodeposition uniformity.

<Example 3>

After the coin plating solution containing the following components were prepared on the basis of 1 liter, the experimental conditions were performed in the same manner as in Example 1, and then the plated state and the surface state of the plated material inside the printed circuit board hole were confirmed.

ingredient content Copper Sulfate Pentahydrate 85 g / L Sulfuric acid 100 ml / l Chlorine Ion 40 ppm N-isopropylcysteine 0.005 g / L Cysteine N-carbodithioic acid 0.01 g / L Bis- (sodium sulfopropyl) -disulfide 0.01 g / L Poly (diallyldimethylammonium chloride) 0.2 g / L Diallylamine 0.02 g / L

Coin plating was carried out in the composition as described above to form a plating excellent in the gloss and film properties of the PCB surface and excellent electrodeposition uniformity.

The composition of the acidic anticorrosive solution for PCB through-hole plating according to the present invention is a sulfur compound containing a cysteine derivative material, a water-soluble mercapto organic brightener, a carrier and a wetting agent, a leveling agent and a fine agent, each of which contains an additive component, as described above. When the compound is added to at least one or more, and used in a specific combination, it was confirmed that the coating property is excellent and the plating property is excellent in the uniform electrodeposition property of the PCB surface and the through hole.

As described above, the composition of the acidic anticorrosive solution for PCB through hole plating according to the present invention is composed of a cysteine derivative sulfur compound organic polish agent by organic synthesis, which has a long bath life, and has excellent gloss and film properties. Since the uniform electrodeposition property of the through hole has a very excellent plating property, it can be very useful for obtaining a high density and multilayered printed circuit board material product having improved product quality and reliability.

Claims (3)

Acid and copper salts and chlorine ions, cysteine derivative sulfur compounds and water-soluble mercapto organic brighteners, carriers and wetting agents, homogenizers and micronizing agents comprising a plating solution comprising a compound corresponding to the cysteine derivative sulfur compounds and water-soluble mercapto organic brightener compounds N-ethyl cysteine 0.001g-2.0g, N-propylcysteine 0.001g-2.0g, N-isopropylcysteine 0.001g-3.0g, N-isobutylcysteine 0.001g-3.0 g, N-cyclohexylsteine 0.002g-2.0g, N- (cyclohexylmethyl) cysteine 0.001g-2.0g, S- (tert-butylthio) cysteine 0.001g-1.0g, cysteine N-carbodithioic acid An acidic coin plating composition which is added in combination of at least one or more from 0.001 g to 1.0 g of a compound group. The cysteine derivative water-soluble mercapto organic brightener according to claim 1, wherein the N-alkyl (C1-C5), N-dialkyl (C1-C5), N-isoalkyl (C1-C5), N-cycloalkyl (C3-- C8). The method according to claim 1, wherein the content of acetamide is 0.01 g to 1.0 g based on 1 liter of the plating solution with the compound corresponding to the leveling agent and the micronizing agent compound group. 0.01 g to 1.0 g of sulfanylamide, 0.01 g to 1.0 g of diallylamine, 0.001 g to 0.01 g of 4-toluenesulfonamide, 0.001 g to 0.3 g of cetyltrimethylammonium chloride, (3-chloro-2-hydroxypropyl) Trimethylammonium chloride 0.001g to 0.3g, octyltrimethylammonium chloride 0.001g to 0.3g, poly (diallyldimethylammonium chloride) 0.01g to 0.5g, benzyldimethyl (2-hydroxyethyl) ammonium chloride 0.001g to 0.3g Composition.