WO2007032222A1

WO2007032222A1 - Electroless plating catalyst for printed wiring board having through hole, and printed wiring board having through hole processed by using such catalyst

Info

Publication number: WO2007032222A1
Application number: PCT/JP2006/317461
Authority: WO
Inventors: Toshifumi Kawamura; Toru Imori
Original assignee: Nippon Mining & Metals Co., Ltd.
Priority date: 2005-09-15
Filing date: 2006-09-04
Publication date: 2007-03-22
Also published as: KR100970067B1; JPWO2007032222A1; JP2011091427A; TW200714745A; TWI331173B; KR20080048043A; JP4889045B2

Abstract

Provided is an electroless plating catalyst, by which uniform electroless plating can be performed without generating voids on a through hole side wall, even to a printed wiring board with a through hole having a diameter of 200μm or less due to high integration of the printed wiring board. The electroless plating catalyst to be used for printed wiring boards having through holes is characterized in that the catalyst includes a compound having a functional group which can capture a noble metal in a molecule, and a noble metal compound.

Description

Catalyst for electroless plating on printed wiring board having through hole, and printed wiring board having through hole processed using the catalyst

Technical field

The present invention relates to an electroless plating catalyst used for a printed wiring board having a through hole, and a printed wiring board having a through hole processed using the catalyst.

Background art

[0002] When an electroless plating such as copper or nickel is applied to a base material of a printed wiring board to form a metal layer, the electroless plating is formed in order to form the base layer uniformly on the base material. There is known a pretreatment method in which a catalyst such as palladium is applied to the surface of a base material before application. For example, a method of immersing a substrate in a Sn Pd colloid solution, a method of attaching a catalyst by vapor deposition or sputtering, and the like are used. Also in printed wiring boards having through holes for connection, it is known that after forming the through holes, pretreatment is performed in the same manner, and a metal layer is formed by electroless plating (Patent Document 1, Patent). (Ref. 2).

[0003] In recent years, in response to demands for downsizing, weight reduction, and high speed of electronic devices, the density of printed wiring boards has been increasing. Along with the increase in the density of printed wiring boards, the diameter of through holes in printed wiring boards with through-holes has been reduced from over 200 μm to 200 m or less. For printed wiring boards with through-holes, it is desirable to have an adhesive layer evenly formed on the sidewalls of the through-holes. The problem is the formation of voids (parts that are slightly unspotted) on the side walls of the steel. This is considered to have occurred because the catalyst was not uniformly applied to the sidewall of the through hole having a small diameter when the catalyst was applied in the pretreatment.

[0004] As a method of applying a catalyst, in the method of immersing a substrate in the above Sn-Pd colloid solution, the Sn-Pd colloid is large in a printed wiring board having a through hole having a diameter of 200 m or less ( Particle size 0.1 ~: LO m) On the side wall of one hole, the catalyst is liable to generate voids. In addition, the plating process using Sn—Pd colloid prevents the generation of voids by performing a plurality of catalyst application steps + plating steps, which makes the process complicated and costly. In addition, in the case of vapor deposition sputtering, it is difficult to apply a catalyst uniformly to the side wall of the through hole.

Patent Document 1: Japanese Patent Laid-Open No. 2005-136316

Patent Document 2: U.S. Patent 6,630,743 B2 Specification

Disclosure of the invention

Problems to be solved by the invention

[0005] According to the present invention, even if a printed wiring board having a through hole having a diameter of 200 m or less is formed by increasing the density of the printed wiring board, voids are not generated on the side wall of the through hole, and the electroless electrode is uniformly electroless. An object of the present invention is to provide an electroless plating catalyst capable of being attached. Means for solving the problem

[0006] As a result of intensive studies on the above problems, the present inventors have used a catalyst containing a compound having a functional group capable of capturing a noble metal in the molecule and a noble metal compound as a catalyst for the substrate. We found that by attaching and electroless plating, even on printed wiring boards with through-holes with a diameter of 200 m or less, they are evenly attached to the side walls of the through-holes.

That is, the present invention is as follows.

(1) A catalyst for electroless plating used for a printed wiring board having a through hole, comprising a compound having a functional group capable of capturing a noble metal in the molecule and a noble metal compound. Catalyst.

(2) The compound having a functional group capable of capturing a noble metal in the molecule is a silane coupling agent, and is obtained by a reaction of an azole or amine compound with an epoxy silane compound. (1) The electroless plating catalyst according to (1).

(3) The electroless plating catalyst according to (1), wherein the compound having a functional group capable of capturing a noble metal in the molecule is a silane coupling agent having an amino group.

(4) In the above (1) to (3), the noble metal compound is a palladium compound V, catalyst for electroless plating according to any one of the above.

(5) A diameter of 200 m or less, characterized by being electrolessly plated after being treated with the electroless plating catalyst according to any one of (1) to (4) above. Printed wiring board with fine through holes.

The invention's effect

[0008] A printed circuit board having a through hole that has been electrolessly plated after being treated with the electroless plating catalyst of the present invention has a through hole even if the through hole has a diameter of 200 μm or less. The side walls are uniformly plated and no voids are generated. Therefore, the process can be simplified and the yield can be improved.

Brief Description of Drawings

FIG. 1 is a photograph of the inside of a through hole after electroless plating in Example 1.

FIG. 2 is a photograph of the inside of a through hole after electroless plating in Comparative Example 1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] The present invention is an electroless plating catalyst used for a printed wiring board having a through-hole, and includes a compound having a functional group capable of capturing a noble metal in a molecule and a noble metal compound.

[0011] With a compound having a functional group capable of capturing a noble metal in the molecule and a catalyst containing the noble metal compound, the noble metal catalyst is formed via a compound having a functional group capable of capturing the noble metal in the molecule with respect to the surface to be bonded. It can fix more uniformly and reliably. In addition, since the catalyst has a small molecular size, it can easily go into the small-diameter through-hole, and can be firmly and evenly fixed on the side wall of the through-hole. For this reason, when electroless plating is applied after the catalyst is deposited, uniform plating can be achieved without generating voids.

A preferable compound having a functional group capable of capturing a noble metal in the molecule is a silane coupling agent, which is obtained by reacting an azole compound or an amine compound with an epoxy compound. Can be mentioned.

Examples of azole compounds include imidazole, oxazole, thiazole, selenazole, pyrazole, isoxazole, isothiazole, triazole, oxadiazole, thiadiazole, tetrazole, oxatriazole, thiatriazole, bendazol. And indazole, benzimidazole, benzotriazole and the like. Although not limited to these, imidazole is particularly preferred.

Examples of the amine compound include saturated hydrocarbon amines such as propylamine, unsaturated hydrocarbon amines such as berylamine, and aromatic amines such as phenylamine.

[0014] The silane coupling agent is a compound having a -SIX X X group in addition to the noble metal capturing group derived from the azole compound or the amine compound, and X, X, and X are alkyl.

1 2 3 1 2 3 group, halogen, alkoxy group, etc., and any functional group that can be fixed to the object. X, X, and X may be the same or different.

one two Three

[0015] The silane coupling agent can be obtained by reacting the azole compound or amine compound with an epoxy silane compound.

As such an epoxy silane compound,

[Chemical 1]

C H2-C H- CH 2 O (C H2) ₃ S i (OR ^ n R ² On)

(Where

R ² represents hydrogen or an alkyl group having 1 to 3 carbon atoms, and n represents 0 to 3. An epoxy coupling agent represented by

[0016] The reaction of the azole compound and the epoxy group-containing silane compound can be carried out under the conditions described in, for example, JP-A-6-256358.

For example, it can be obtained by dropping 0.1 to 10 moles of an epoxy group-containing silane compound at 80 to 200 ° C and reacting for 5 minutes to 2 hours with respect to 1 mole of an azole compound. In that case, an organic solvent such as force form, dioxane, methanol, ethanol or the like, which does not particularly require a solvent, may be used.

[0017] Particularly preferred is a reaction of an imidazole compound and an epoxysilane compound as an example.

[Chemical 2] H ₂ 0 (CH ₂ ) ₃ S i (OR ¹ ), R ² _(3. _N)

CH ₂ 0 (CH ₂ ) 3 S i (OR ^-1 ) _n R ^z ₍₃ _ _n)

(Where

R ² is hydrogen or an alkyl group having 1 to 3 carbon atoms, R ³ is hydrogen or an alkyl group having 1 to 20 carbon atoms, R ⁴ is a bur group, or an alkyl group having 1 to 5 carbon atoms, n is 0 to 3 is shown. )

[0018] Other examples of the compound having a functional group capable of capturing a noble metal in the molecule used in the present invention include, for example, a silane coupling agent having an amino group, a mercapto group, etc. as a functional group capable of capturing a noble metal. Y-aminopropyltrimethoxysilane, y-aminopropyl pilltriethoxysilane, N-β (aminoethinore) _γ —aminopropyltrimethoxysilane, Ν-β (aminoethyl) γ-aminopropyltriethoxy Examples include silane and γ-mercaptoprovir trimethoxysilane.

[0019] Examples of the noble metal compound include noble metal compounds such as palladium, silver, platinum, and gold, such as halides, hydroxides, sulfates, carbonates, carboxylic acids, sulfonic acids, and sulfinic acids. A salt with an organic acid, a precious metal sarcophagus, etc. can be mentioned. Particularly preferred is a palladium compound. The palladium compound is not particularly limited as long as palladium ions are supplied, but halides, sulfates, carboxylates and the like are preferably used. For example, palladium chloride, palladium sulfate, palladium acetate. Etc. Further, a conventional catalyst such as tin chloride can be contained within the scope of the object of the present invention.

[0020] The catalyst of the present invention is used as a solution of a compound having a functional group capable of trapping a noble metal in the molecule or a noble metal compound, but the solvent is capable of trapping the noble metal in the molecule. An aqueous solution that has the ability to dissolve the compound having a functional group or a noble metal compound and has a safety point is preferable. Depending on solubility, alcohol-based organic solvents such as methanol, ethanol, isopropanol and octyl alcohol, and aromatic organic solvents such as toluene and xylene may be used as appropriate.

[0021] The concentration of the compound having a functional group capable of capturing a noble metal in the molecule in the catalyst is not limited to this, but is preferably 0.001 to 10% by weight. When the amount is less than 001% by weight, the amount of the compound adhering to the surface of the substrate becomes low and it is difficult to obtain the effect immediately. On the other hand, if it exceeds 10% by weight, it is difficult to dry due to too much adhesion, or the balance with the trapped noble metal is lost and it takes time to develop the catalytic activity, and the effect is obtained.

[0022] The noble metal compound can be used in the catalyst at a concentration of 1 to: LOOOmgZL (in terms of noble metal), preferably 10 to 300 mgZL (in terms of noble metal). Although the effect is seen outside this range, the influence of post-treatment is also preferably within the above range.

[0023] As a method of treating the substrate with a catalyst, dipping is preferable so that the substrate is uniformly applied to the side wall of the through hole.

As a printed wiring board having a through hole of the present invention, for example, after forming a through hole in a base material, a regular degreasing process and a soft etching process are performed, and then the catalyst described so far is applied by immersion, An electroless plating layer such as copper or nickel is formed by a conventional method. After applying the catalyst, it is preferable to wash with water and activate the catalyst with, for example, 10% sulfuric acid, 5% sodium hypophosphite and the like at room temperature of 70 ° C for 1 minute at 15 minutes.

[0024] The wiring board having a through hole according to the present invention has a printed wiring board uniformly plated with no voids even on the side wall of a through hole having a diameter of 200 μm or less, for example, a diameter of 150 m. Become.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples.

[0026] Example 1

A printed circuit board multilayer substrate with a 150 m diameter through hole It was immersed for 5 minutes at 40 ° C. in an aqueous solution containing 100 mg ZL of silane (the reaction product of imidazole and 3-glycidoxypropyltrimethoxysilane) and 50 mg ZL of palladium chloride (30 mg ZL in terms of Pd). This was treated with an activator (5% sodium diphosphite) at 40 ° C for 5 minutes to make Pd electroless plating activity. Electroless copper plating (Cuposit 328, manufactured by R & H) was performed at room temperature for 20 minutes to form a copper layer with a thickness of 0.5 m. When the inside of the 1000-hole through hole was observed, it was found that all were attached (see Fig. 1).

[0027] Example 2

A laminated board for printed wiring boards having a 150 m diameter through hole is placed in an aqueous solution containing aminosilane (γ-aminopropyltriethoxysilane) lOOmgZL and palladium acetate lOOmgZL (47 mgZL in terms of Pd) at 40 ° C for 5 minutes. Soaked. This was treated with an activator (5% sodium diphosphite) at 40 ° C for 5 minutes to make Pd electroless plating activity. Electroless copper plating (Cuposite 328, manufactured by R & H) was performed at room temperature for 20 minutes to form a 0.5 μm thick copper layer. When the inside of the 1000-hole through hole was observed, it was found that all were attached.

[0028] Comparative Example 1

A laminated board for printed wiring boards having a 150 m diameter through hole is immersed in a commercially available Sn—Pd colloid process (as a pre-dip solution, Kata Lip 404 (manufactured by R & H)). And then washed with water and treated once with AXELATOR 19E (manufactured by R & H) as an activator solution to make it electroactive. Thereafter, electroless copper plating was performed in the same manner as in Example 1. When the inside of the 1000-hole through hole was observed, voids were seen in 100 holes. Figure 2 shows a cross-sectional view of the through hole where voids were observed. The part that appears black in the through hole (dark part) is the non-stick part (void). In the through hole of Example 1 shown in Fig. 1, the dark part is not found and there is no uncovered part, but in Comparative Example 1 shown in Fig. 2, the upper force of the through hole in Fig. 2 is also fitted to 1Z4 ( The dark part is not found), but after 1Z4, the black part gradually becomes darker, and the lower 1Z4 is almost black.

Claims

The scope of the claims

[1] A catalyst for electroless plating used for a printed wiring board having a through hole, characterized in that it contains a compound having a functional group capable of capturing a noble metal in the molecule and a noble metal compound. Catalyst for plating.

[2] The compound having a functional group capable of capturing a noble metal in the molecule is a silane coupling agent, and is obtained by a reaction of an azole or amine compound with an epoxy silane compound. 2. The electroless plating catalyst according to claim 1.

[3] The electroless plating catalyst according to claim 1, wherein the compound having a functional group capable of capturing a noble metal in the molecule is a silane coupling agent having an amino group. .

[4] The electroless plating catalyst according to any one of claims 1 to 3, wherein the noble metal compound is a palladium compound.

[5] A diameter of 200 m or less, characterized by being electrolessly plated after being treated with the electroless plating catalyst according to any one of claims 1 to 4. Printed wiring board with fine through holes.