JP2001254182A - Method of preparing electroless plating catalyzing solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of preparing an electroless plating catalyzing solution by which the adsorptivity of palladium colloid on a face to be plated is enhanced, the subsequent copper plating is made uniform, and a rigid plating film is deposited. SOLUTION: A cationic group is incorporated into an electroless plating catalyzing solution, and the solution is made neutral to alkaline. A (co)polymer and/or a polycondensate which are never hydrolyzed and with the macromolecule hardly deteriorated is added to the solution, and an electroless plating catalyzing solution is prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a catalyst solution for electroless plating, and more particularly, to preparing a catalyst solution for electroless plating, adding a specific cationic (co) polymer to palladium. The present invention relates to a method for preparing an electroless plating catalyst solution capable of improving the adsorption of colloid to a surface to be plated and improving the subsequent copper plating treatment.

[0002]

2. Description of the Related Art During a process of manufacturing a printed wiring board, a through hole is formed between a front surface and a back surface to allow a current to flow, and copper plating is performed on the surface of the through hole to ensure conductivity. You. Usually, a cationic surfactant has conventionally been used for the purpose of increasing the adsorbability of the colloid in order to adsorb the palladium colloid and the tin colloid on the surface of the sulfol as a pretreatment for copper plating. In order to improve the quality, cationic polymers have been used.
For example, in U.S. Pat. No. 4,478,883, immersion treatment is performed in an aqueous solution of acrylamide / .beta.-methacryloyloxyethyltrimethylammonium methylsulfuric acid copolymer as a pretreatment for electroless plating. In this method, since the cationic polymer is not directly mixed into the plating catalyst solution, it is not necessary to consider the deterioration of the cationic polymer. Since electroless is usually adjusted from pH 6 to about 10 from neutral to alkaline, it is necessary to consider the alkali resistance of the cationic polymer when directly blending it into the plating catalyst solution. As described above, the cationic polymer formulation has not been completely established yet, and there are various conditions to be examined, and it is in the stage of trial and error.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to examine what kind of cationic polymer is contained in an electroless catalyst solution so that a uniform and strong plating film can be mounted.

[0004]

As a result of intensive studies to solve the above problems, it has been found that the above problems can be solved by adding a specific cationic polymer to an electroless catalyst solution, and the present invention has been achieved. That is, the invention of claim 1 of the present invention is characterized in that at least one of a (co) polymer having the following structural unit (1) and / or a polycondensate of (2) to (3) is added. This is a method for preparing an electroless plating catalyst solution. (1) Dialkylaminopropyl (meth) acrylamide structural unit, (meth) acryloylaminopropyltrialkylammonium chloride structural unit (the alkyl group is
All are methyl and ethyl), diallyldimethylammonium chloride structural unit (2) alkylamine / epichlorohydrin / polyalkylenepolyamine and / or ammonia polycondensate (alkyl groups are methyl, ethyl and benzyl) alkylamine / epichloro Hydrin polycondensate (alkyl group is methyl, ethyl and benzyl)

According to a second aspect of the present invention, the (co) polymer comprises:
The method for preparing an electroless plating catalyst solution according to claim 1, comprising a diallyldimethylammonium chloride structural unit, a vinylamine structural unit and / or a vinylamidine structural unit.

The invention according to claim 3 is that the (co) polymer comprises:
A polymer containing a diallyldimethylammonium chloride structural unit (a mol%) and a vinylamine structural unit (b mol%) and / or a vinylamidine structural unit (c mol%), wherein a, b, and c are 30 ≦ (a) ≦ 9
The method for preparing an electroless plating catalyst solution according to claim 1, wherein a range of 0, 10 ≦ (b) ≦ 70, and 0 ≦ (c) ≦ 60 is satisfied.

According to a fourth aspect of the present invention, the (co) polymer comprises:
The method for preparing an electroless plating catalyst solution according to claim 1, wherein the method has a dialkylaminopropyl (meth) acrylamide structural unit of 50 to 100 mol%.

According to a fifth aspect of the present invention, the (co) polymer comprises:
The method for preparing an electroless plating catalyst solution according to claim 1, comprising 50 to 100 mol% of (meth) acryloylaminopropyltrialkylammonium chloride units.

The invention of claim 6 is the preparation of the electroless plating catalyst solution according to any one of claims 1 to 5, wherein the molecular weight of the (co) polymer (1) is 10,000 to 1,000,000. Is the way.

[0010] The invention of claim 7 is the method for preparing an electroless plating catalyst solution according to any one of claims 1 to 6, which contains a palladium colloid.

[0011]

8. The method according to claim 1, wherein the pH is from 5.0 to 11.0.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The (co) polymer having a dialkylaminopropyl (meth) acrylamide structural unit of (1) is a homopolymer of dimethylaminopropyl (meth) acrylamide or diethylaminopropyl (meth) acrylamide, or a non-polymer. It is a copolymer with an ionic monomer. Examples of nonionic monomers include (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone , N-vinylformamide, N-vinylacetamide, acryloylmorpholine and the like. The molar percentage of dialkylaminopropyl (meth) acrylamide in the copolymer is 5%.
It is 0 to 100 mol%, preferably 80 to 100 mol%. If it is less than 50 mol%, the effect is low and it cannot be used.

Examples of (1) a (co) polymer having a (meth) acryloylaminopropyltrialkylammonium chloride structural unit include (meth) acryloylaminopropyltrimethylammonium chloride and (meth) acryloylaminopropyltriethyl. It is a homopolymer of ammonium chloride or a copolymer with a nonionic monomer. As examples of the nonionic monomer, those similar to the above are used. In addition, (meth) in the copolymer
The molar percentage of acryloylaminopropyltrialkylammonium chloride is 50 to 100 mol%, preferably 80 to 100 mol%, as described above.

The (co) polymer (1) having a diallyldimethylammonium chloride structural unit can be synthesized by homopolymerization of diallyldimethylammonium chloride or copolymerization with the above-mentioned nonionic monomer. it can.
Further, in order to synthesize a polymer in which a polymer having a diallyldimethylammonium chloride structural unit and a vinylamine structural unit coexist, an N-vinylformamide copolymer can be synthesized by hydrolysis with an acid or an alkali. The mol% of the diallyldimethylammonium chloride structural unit in the copolymer is 50 to 100 mol%, preferably 70 to 10 mol%.
0 mol%, and the mol% of the vinylamine structural unit is 0 mol%.
-50, preferably 0-30 mol%. Further, a polymer having a diallyldimethylammonium chloride structural unit and a vinylamine structural unit and / or a vinylamidine structural unit coexists is obtained by hydrolyzing a diallyldimethylammonium chloride / N-vinylformamide / acrylonitrile copolymer with an acid. Can be decomposed and synthesized. The diallyldimethylammonium chloride structural unit in the copolymer is 10 to 50 mol%, and the vinylamidine structural unit is 10 to 10 mol%.
50 mol%, the vinylamine structural unit has 0 to 80 mol%, preferably 20 to 50 mol% of diallyldimethylammonium chloride structural unit, 20 to 50 mol% of vinylamidine structural unit, and 0 to 60 mol of vinylamine structural unit. %.

The molecular weight of the (co) polymer (1) is 10,000 to 1,000,000. If it is 10,000 or less, the effect of improving the adsorptivity of the palladium colloid is low.
If the molecular weight is more than 10,000, the molecular weight is too high to form a uniform copper plating film.

The alkylamine / epichlorohydrin polycondensate (2) (the alkyl group is methyl, ethyl and benzyl) is a polycondensate of monomethylamine, monoethylamine, dimethylamine or diethylamine with epichlorohydrin. is there. The molecular weight of the polycondensate of (2) is from 600 to 10,000. The alkylamine / epichlorohydrin / polyalkylenepolyamine and / or ammonia polycondensate (the alkyl group is methyl, ethyl and benzyl) of (3) can be obtained by mixing monomethylamine, monoethylamine, dimethylamine or diethylamine with epichlorohydrin. Is further reacted with a polyalkylene polyamine and / or ammonia as a linking agent to increase the molecular weight. Examples of the polyalkylene polyamine include diethylene triamine, triethylene tetramine, and pentaethylene hexamine. The molecular weight of the polycondensate of (3) is about 10,000 to tens of thousands.

The electroless plating catalyst solution of the present invention contains a palladium colloid and metallic copper similarly to a commonly used catalyst solution, and optionally contains a tin colloid, a surfactant, and other pretreatment agents. Organic chemicals can be contained. Since the pH of the catalyst solution is generally maintained at about 6 to 10, cationic acrylic esters are not practical because of severe hydrolysis. On the other hand, the cationic polymer used in the present invention has no ester bond in the molecule, and therefore is less likely to be hydrolyzed on the alkali side and is stable.

Since the polyimide resin, epoxy resin, or glass constituting the printed wiring board laminate is easily charged to a negative charge, the added cationic polymer is presumed to be adsorbed on the surface of the laminate. For this reason, the palladium colloid or tin colloid improves the adsorptivity to the wiring board. Further, some cationic polymers are also adsorbed on the surface of the colloid particles, the surface is charged to a positive charge, and the adsorbability to the surface of the wiring board is improved. Thereafter, if a treatment with an electroless plating solution is performed, a good plating film is formed. Therefore, a uniform and good plating film can be formed even in a place where plating treatment is difficult, such as a through hole.

[0019]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless it exceeds the gist thereof.

(Synthesis Example 1) A 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a monomer supply tube connected to a peristaltic pump (SMP-21, manufactured by Tokyo Rika Kikai), and a condenser. Dimethyl diallyl ammonium chloride (trade name DADMAC, 65% by weight)
138.5 g, ion-exchanged water 161.
5 g was injected, the temperature inside the reactor was kept at 50 ° C., and the atmosphere was replaced with nitrogen for 30 minutes. Then, 2.7 g of a 10% aqueous solution of 2,2-azobisamidinopropane dichloride (based on monomer 0.1%).
(3%) was added to initiate polymerization. The reaction was continued at 50 ° C., and after 7 hours, 2.7 g of 2,2-azobisamidinopropane dihydrochloride was added, and the reaction was further continued for 10 hours to complete the reaction. After the polymerization, the cation equivalent was measured by a colloid titration method, and the weight average molecular weight was measured by a molecular weight measuring apparatus (DLS-7000, manufactured by Otsuka Electronics Co., Ltd.) by a static light scattering method. This polymer is referred to as test sample-1. Table 1 shows the results.

(Synthesis Example 2) A 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a monomer supply tube connected to a peristaltic pump (SMP-21, manufactured by Tokyo Rika Kikai) and a condenser. Dimethyl diallyl ammonium chloride (trade name DADMAC, 65% by weight)
55.7 g, ion-exchanged water 196.0
g and 0.9 g of a 10% aqueous solution of 2,2-azobisamidinopropane dihydrochloride (0.1 g for all monomers used).
15%). Separately, 23.9 g of N-vinylformamide (manufactured by Mitsubishi Chemical) and 23.9 g of ion-exchanged water
g was mixed to prepare an aqueous solution. While stirring the raw material mixture, the temperature was maintained at 40 ° C., nitrogen was introduced thereinto, and the polymerization was allowed to proceed for 30 minutes. Then, the N-vinylformamide aqueous solution was supplied into the flask at a rate of 0.4 g / min for 2 hours. The molar ratio between DADMAC and N-vinylformamide after the end of the supply is 40:60. Four hours after the completion of the supply, 1.2 g of a polymerization initiator solution was added. Twelve hours after the start of the polymerization, the heat retention was stopped to stop the polymerization. Thereafter, 35% hydrochloric acid.
5 g (based on 100 mol% of N-vinylformamide) was added, and the mixture was hydrolyzed at 90 ° C. for 5 hours to generate a primary amino group in the molecule. After the reaction, the ion equivalent (meq / g), primary and quaternary amino groups are measured by a colloid titration method, and a molecular weight measuring device (DL made by Otsuka Electronics Co., Ltd.) is measured by a static light scattering method.
S-7000). This is designated as test sample-2. The results are shown in Table 1.

(Synthesis Example-3) A 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a monomer supply tube connected to a peristaltic pump (SMP-21, manufactured by Tokyo Rika Kikai) and a condenser. Dimethyl diallyl ammonium chloride (trade name DADMAC, 65% by weight)
Product, made by Daiso) 60.3 g, ion-exchanged water 190.3
g and 1.5 g of a 10% aqueous solution of 2,2-azobisamidinopropane dihydrochloride (0.1 g for all monomers used).
2%). Separately, 23.6 g of N-vinylformamide (manufactured by Mitsubishi Chemical) and acrylonitrile
An aqueous solution was prepared by mixing 9 g and 35.5 g of ion-exchanged water. While stirring the raw material mixture, the temperature was kept at 40 ° C., nitrogen was introduced and polymerization was allowed to proceed for 30 minutes.
A mixed aqueous solution of vinylformamide / acrylonitrile was fed into the flask at 0.59 g / min for 2 hours. The molar ratio of DADMAC / N-vinylformamide / acrylonitrile after the end of the supply is 30:35:35. Four hours after the completion of the supply, 1.2 g of a polymerization initiator solution was added. Twelve hours after the start of the polymerization, the heat retention was stopped to stop the polymerization. Thereafter, 41.7% of 35% hydrochloric acid (100 mol% of N-vinylformamide) was added, and the mixture was hydrolyzed at 90 ° C. for 5 hours to generate a primary amino group in the molecule. After the reaction,
The ion equivalent (meq / g), primary and quaternary amino groups were measured by a colloid titration method, and the weight average molecular weight was measured by a molecular weight measuring device (DLS-7000 manufactured by Otsuka Electronics) by a static light scattering method. This is designated as test sample-3. The results are shown in Table 1.

(Synthesis Example-4) A 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a monomer supply tube connected to a peristaltic pump (SMP-21, manufactured by Tokyo Rika Kikai), and a condenser. 75.0 g of dimethylaminopropylacrylamide (produced by Kojin), 225.0 g of ion-exchanged water, and the temperature in the reactor was kept at 50 ° C.
After purging with nitrogen for 30 minutes, 3.75 g of a 10% aqueous solution of 2,2-azobisamidinopropane dichloride (0.55% of monomer) was added to initiate polymerization. The reaction was continued at 50 ° C., and after 7 hours, 3.75 g of the above-mentioned aqueous solution of 2-azobisamidinopropane dichloride was added, and the reaction was further continued for 10 hours to complete. After the polymerization, the cation equivalent was measured by a colloid titration method, and the weight average molecular weight was measured by a molecular weight measuring device (DLS-7000, manufactured by Otsuka Electronics Co., Ltd.) by a static light scattering method. This polymer is designated as test sample-4. Table 1 shows the results.

(Synthesis Example-5) A polymer of acryloylaminopropyltrimethylammonium chloride was synthesized in the same manner as in Synthesis Example-4. This is designated as Test Product-5.

(Synthesis Example-6) A 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a monomer supply tube connected to a peristaltic pump (SMP-21, manufactured by Tokyo Rika Kikai), and a condenser. 90.0 g of a 50% aqueous solution of dimethylamine and 97.8 g of ion-exchanged water were put therein. Then, the temperature was reduced to 50 ° C. while cooling the reactor with ice water.
While keeping below, 101.8 g of epichlorohydrin
Supplied over time. The molar ratio is 1: 1.1. Thereafter, the reaction was performed for 5 hours, and the reaction was completed. This is designated as Test Product-6.

(Synthesis example-7) Next, 200 of test sample-6
g, and 13.3 g of pentaethylenehexamine of 5 mol% with respect to the initial molar ratio of epichlorohydrin was added. The reaction was carried out at 40 ° C., and when the viscosity increased, hydrochloric acid was added to terminate the reaction. The cation equivalent and the molecular weight were measured as in the other synthesis examples. This is designated as Test sample-7.

[0027]

EXAMPLE 3.3 Cupric chloride 3.3 in 4500 ml of deionized water
6 g and 0.44 g of palladium chloride are dissolved. Thereafter, a solution of 2.5 g of sodium borohydride in 200 ml of deionized water is added. Following the palladium ions, the copper ions are reduced and the solution turns black. After continuing to stir for 10 minutes, after confirming that the color change disappeared, the pH was adjusted to 9.2, deionized water was added, and the total amount was reduced to 5%.
The electroless plating catalyst solution thus prepared was added with 0.2% of the prototypes-1 to 7 of the present invention. Then, after dipping a printed wiring board composed of a laminate of polyimide and glass having a through hole formed with a through hole having a diameter of 0.2 to 0.3 mm for 8 minutes, it is washed with water and then dipped in an electroless plating solution for room temperature for 10 minutes.
Soak for minutes. A uniform and strong plating film was formed on the surface of the printed wiring board and in the through hole.

[0028]

COMPARATIVE EXAMPLE An electroless plating catalyst solution was prepared and electroless plating was performed in the same manner as in the example. In this case, a plating catalyst solution was prepared without adding the cationic polymer of the present invention. After immersion in the electroless plating catalyst solution, electroless copper plating was performed. However, copper plating in the through-hole was not sufficient, and some untreated portions were present.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 18/38 C23C 18/38 // H05K 3/18 H05K 3/18 FF term (Reference) 4J043 QB53 RA08 SA09 SB02 TA38 TB01 UB011 UB012 UB032 UB042 ZA22 ZB60 4J100 AG04Q AL03Q AL08P AL08Q AL09Q AM02Q AM15Q AM19Q AM21P AM21Q AN04Q AN14P AQ08Q BA10Q BA12Q BA18P BA30P BA31P BC79Q CA04 A38A02 A04A38A01 CC71 DD33 ER01 GG01

Claims (8)

[Claims] 1. An electroless plating catalyst solution comprising at least one of a (co) polymer having the following structural unit (1) and / or a polycondensate of (2) to (3): Preparation method. (1) Dialkylaminopropyl (meth) acrylamide structural unit, (meth) acryloylaminopropyltrialkylammonium chloride structural unit (the alkyl group is
All are methyl and ethyl), diallyldimethylammonium chloride structural unit (2) alkylamine / epichlorohydrin / polyalkylenepolyamine and / or ammonia polycondensate (alkyl groups are methyl, ethyl and benzyl) alkylamine / epichloro Hydrin polycondensate (alkyl group is methyl, ethyl and benzyl) 2. The electroless plating catalyst solution according to claim 1, wherein the (co) polymer contains a diallyldimethylammonium chloride structural unit and a vinylamine structural unit and / or a vinylamidine structural unit. Preparation method. 3. The (co) polymer contains a diallyldimethylammonium chloride structural unit (a mol%) and a vinylamine structural unit (b mol%) and / or a vinylamidine structural unit (c mol%). A polymer,
b and c are respectively 30 ≦ (a) ≦ 90 and 10 ≦ (b)
The method for preparing an electroless plating catalyst solution according to claim 1, wherein a range of ≦ 70 and 0 ≦ (c) ≦ 60 is satisfied. 4. The method for preparing an electroless plating catalyst solution according to claim 1, wherein the (co) polymer has 50 to 100 mol% of a dialkylaminopropyl (meth) acrylamide structural unit. 5. The electroless plating catalyst solution according to claim 1, wherein the (co) polymer contains 50 to 100 mol% of (meth) acryloylaminopropyltrialkylammonium chloride units. Preparation method. 6. The (co) polymer of (1) having a molecular weight of 1
The method for preparing an electroless plating catalyst solution according to any one of claims 1 to 5, wherein the amount is from 10,000 to 1,000,000. 7. The method according to claim 1, further comprising a palladium colloid. 8. The method for preparing an electroless plating catalyst solution according to claim 1, wherein the pH is 5.0 to 11.0.