JPH06104579B2 - Metallization method for crystallized glass surface - Google Patents

Description

The present invention relates to a crystallized glass substrate, a crystallized enamel substrate, a crystallized glass surface-coated ceramic substrate, etc. It relates to the metallization method.

(Prior Art) Conventionally, as a method of metallizing the surface of crystallized glass, particularly a circuit forming method, (a) a thick film method of baking a metal paste,
(B) There is a thin film method using sputtering or CVD.

However, (a) in the thick film method, since the circuit is formed by the printing method, it is difficult to perform wiring (circuit formation) on the inner wall of the through hole of the substrate and the curved portion at the end of the substrate.
There is a problem in that a precious metal paste that does not oxidize because of a high temperature exceeding 0 ° C. has to be used and the cost becomes high. (B) Like the thick film method, the thin film method has problems such as difficulty in wiring (circuit formation) to a through hole or a curved surface, poor mass productivity, and difficulty in increasing the metal film thickness. It was

For such problems, a method of plating on the surface of crystallized glass has been proposed. For example, JP-A-53-5438
In the method disclosed in Japanese Patent Laid-Open No. 60-195078, the surface of the crystallized glass is roughened by hydrofluoric acid for the former and sodium hydroxide melt for the latter.

(Problems to be solved by the invention) When hydrofluoric acid or sodium hydroxide melt is used, the corrosive force is too strong and the crystalline phase and the amorphous phase on the surface of the crystallized glass are dissolved without distinction and the roughened surface is uneven. In addition, it is difficult to control and the fragile layer is formed in the vicinity of the surface, so that the electroless plating film applied thereafter peels off together with the fragile layer, and it is difficult to obtain a stable adhesive force.

Also, handling hydrofluoric acid or sodium hydroxide melt is dangerous.

The present invention provides a method for metallizing a surface of crystallized glass having excellent adhesion.

(Means for Solving Problems) In the present invention, the surface of a crystallized glass composed of a crystalline phase and an amorphous phase is treated with (a) a roughening liquid having a higher dissolution rate of the amorphous phase than that of the crystalline phase. A roughening step, (b) a step of applying a catalyst capable of starting an electroless plating reaction, and (c) a step of performing electroless plating.

The roughening liquid used in the present invention is a neutral or near-neutral aqueous solution and has different solubilities with respect to phases having different compositions of crystallized glass.

Generally, the water resistance, acid resistance, and alkali resistance of oxides are as follows [Naruse Ministry "Glass Optics" (Sho 33) Kyoritsu Shuppan).

Water resistance: ZrO ₂ ＞ Al ₂ O ₃ ＞ TiO ₂ ＞ ZnO ＞ MgO ＞ PbO ＞ CaO ＞ BaO Acid resistance: ZrO ₂ ＞ Al ₂ O ₃ ＞ ZnO ＞ CaO ＞ TiO ₂ ＞ PbO ＞ MgO ＞ BaO NaOH resistance ： ZrO ₂ 》 Al ₂ O ₃ , TiO ₂ , ZnO, CaO Na ₂ CO ₃ resistance: ZaO ₂ 》 Al ₂ O ₃ , TiO ₂ , ZnO> CaO, BaO, PbO, MgO As crystalline components in crystallized glass When BaO, CaO, MgO, PbO, etc. are used, the crystalline phase is easily dissolved in both strong acid and strong alkali. Therefore, by performing a treatment that strongly dissolves the amorphous phase in a neutral or near-neutral aqueous solution and leaves the crystalline phase, a roughened surface that increases the adhesion with the plating film to be applied later is obtained. Can be formed.

Although crystallized glass is composed of a crystalline phase and an amorphous phase, the crystalline phase may be composed of several kinds of phases (compositions). In the present invention, at least one of the crystalline phases is used. Roughening is performed with a roughening liquid having a higher dissolution rate of the amorphous phase. As a result, at least one crystalline phase remains on the roughened surface,
The roughened surface can be formed so as to increase the adhesion with the plating film applied thereafter.

In the present invention, for example, boron, silicon, magnesium,
Barium is added to 15 <B ₂ O ₃ <35, 10 <SiO ₂ <3O, 40 <Mg + CaO
Crystallized glass containing + BaO <65 (mol%) can be used.

This crystallized glass consists of a BaO-rich crystalline phase and a borosilicate glassy phase. The crystalline phase is acicular with a length of 20 μm or less and is dispersed innumerably in the amorphous matrix.

Roughening is, for example, sodium fluoride, potassium fluoride,
An aqueous solution of a fluoride salt such as ammonium fluoride, boron fluoride, or ammonium tetrafluoroborate, or a commercially available electroless nickel plating solution "Blue-Summer"
(PH6.4) (product name of Kanigen Japan) and the like. The pH of the roughening solution is 2 to 13, preferably 5 to 10, and more preferably 6 to 9.

As the catalyst capable of initiating the electroless plating reaction, an ordinary catalyst used as a pretreatment for forming a circuit on the surface of the insulating substrate by electroless plating, particularly an alkaline or neutral Pb-based catalyst is preferable. Electroless plating can also be performed in the production of printed wiring with a normal electroless plating solution for forming a circuit on the surface of an insulating substrate.

Example 1,2, Comparative Examples 1,2,3 B ₂ O ₃ = 20, SiO ₂ = 15, MgO = 55, BaO = 5, SrO = 5 composition (mol%) of the crystallized glass, respectively Electrolytic nickel plating solution "Blue-Summer" (trade name of Kanigen Japan Co., Ltd.) is used as a roughening solution, immersed at 75 to 80 ° C for 30 minutes (Example 1), and a 12 g / l aqueous solution of sodium fluoride (pH 7.4) is roughened. As liquid, 75-80
Immersion at 50 ° C for 50 minutes (Example 2) Using a 10N hydrochloric acid 300 ml / l aqueous solution as a roughening solution, immersion at room temperature for 1 minute (Comparative Example 1), hydrofluoric acid (room temperature) for 20 minutes (Comparative Example 2) pH 13 NaOH aqueous solution 75
It was immersed in -80 ° C for 10 minutes (Comparative Example 3).

After dipping in an alkaline Pb seeding solution for 2 minutes, it was dipped in an alkaline reduction solution for 1 minute, and then dipped in an electroless copper plating solution (pH 12, 70 ° C.) containing formalin as a reducing agent for 2 hours. Adhesion between copper plating film and crystallized glass (kg / m
m ² ) was as follows: Example 1: 1.4, Example 2: 1.3 and Comparative Examples 1 to 3: 0.2.

The surface of the crystallized glass substrate after roughening was examined for changes in Ba (crystal component) by XMA (X-ray microanalyzer) analysis of Ba contained in a large amount in the crystalline phase.
2 increased, but Comparative Example 1 decreased and Comparative Examples 2 and 3 did not change. The results of observing the surface after roughening with an SEM (scanning electron microscope) are shown below.

Example 1: Needles having a length of 2 to 3 μm and a width of 0.5 to 1 μm are stacked.

Example 2: Spherical particles of 0.5 to 2 μm are raised.

Comparative Example 1: Cracks having a length of 2 μm or less are present on the entire surface at intervals of 2 μm or less.

Comparative Example 2: Width 0.1 to 0.5 μm, length about 5 μm 2 to 5 cracks
Present at intervals of μm.

Comparative Example 3: Almost no change in the original surface condition.

(Effect of the Invention) According to the present invention, a metal film could be formed on the surface of crystallized glass by plating with good adhesion.

This makes it possible to form circuits by plating,
Wiring (circuit formation) in through-holes and curved surfaces, which has been difficult until now, becomes easy, the sheet resistance value of the conductor circuit can be reduced, and there is no firing, so there is no warpage or dimensional change in the board. It is expected that the cost will be improved and the cost will be drastically reduced.

Claims (2)

[Claims] 1. Boron, silicon, magnesium, and barium are added to 15 <B ₂ O ₃ <35, 10 <SiO ₂ <3O, 40 <MgO + CaO + BaO <65.
And a crystallized glass surface comprising a crystalline phase and an amorphous phase, wherein (a) sodium fluoride having a higher dissolution rate of the amorphous phase than the crystalline phase, Potassium fluoride, ammonium fluoride,
A step of roughening with a fluoride salt aqueous solution such as fluoroboric acid or ammonium tetrafluoroborate; (b) a step of applying a catalyst capable of initiating an electroless plating reaction; (c) a step of performing electroless plating A method for metallizing a surface of a crystallized glass, comprising: 2. The method for metallizing the surface of a crystallized glass according to claim 1, wherein the pH of the roughening liquid is 6-9.