JP3474291B2 - Method for forming plating layer on glass or ceramic substrate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for providing a conductive layer such as an electrode or a printed wiring board on a glass or ceramic substrate, and more particularly, providing a conductive layer having excellent adhesion to the glass or ceramic substrate. The present invention relates to a method for forming a plated layer that can perform

[0002]

2. Description of the Related Art Conventionally, a method of plating a glass or ceramic substrate has been used for forming a conductive layer such as an electrode or a printed wiring on the surface of the substrate.
In the plating layer forming method currently adopted, first, a glass or ceramic substrate is etched with hydrofluoric acid or the like to roughen the substrate surface. This roughening treatment is for improving the adhesion between the substrate and the plating layer formed later by the anchor effect. Next, a palladium catalyst is applied to the surface of the substrate to activate the surface of the substrate, and then electroless plating or electrolytic plating is performed. After that, a resist is applied and then patterned by etching, and then the resist is peeled off from the substrate to obtain a substrate having a patterned conductive layer. However, in such a conventional manufacturing method, since the adhesion between the substrate and the plating layer is based on the anchor effect derived from the roughening of the substrate surface, it is not sufficient, and the electrode or wiring It has been difficult to manufacture a product excellent in durability and quality as a plate or the like. Further, a roughening treatment, a resist applying / removing operation, a work of activating the substrate surface with a catalyst and the like are required, which is a complicated manufacturing method. Therefore, conventionally, there has been a strong demand for a method of forming a plating layer that has excellent adhesion between the substrate and the plating layer and that can be easily performed.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a plating layer forming method capable of easily and significantly improving the adhesion between the substrate and the plating layer.

[0004]

Means for Solving the Problems As a result of earnest studies for achieving the above-mentioned object, the present inventor has found that a coating material containing a copper salt or a silver salt is applied to a substrate surface, dried and baked, and By performing electrolytic plating treatment or electrolytic plating treatment,
The inventors of the present invention have found that the adhesion between the substrate and the plating layer is significantly improved and have reached the present invention. That is, when the copper salt or silver salt contained in the paint is baked on the surface of the glass or ceramic substrate, it changes to the form of copper or silver metal or its oxide and is integrated with the glass or ceramic substrate. To do. Therefore, the layer containing copper and silver firmly adheres to the substrate. Further, since copper or silver also acts as a catalyst in electroless plating or electrolytic plating, the surface of the substrate is activated by these metals and can be immediately subjected to electroless plating or electrolytic plating. Furthermore, since a paint containing a copper salt or a silver salt can be easily applied by a method such as gravure printing, a predetermined pattern can be easily formed without using a resist or the like as in the conventional method. A plating layer can be provided on the substrate.

The present invention will be described in more detail below. As the glass used as the substrate, various commonly used glasses can be used. As such a glass, for example, a silicate glass containing Na ₂ O, SiO ₂ , or CaO as a main component can be cited as a preferable example. Examples of such silicate glass include silicate glass, alkali silicate glass, soda lime glass, potassium lime glass, barium glass, and borosilicate glass. Further, as the ceramics used as the substrate, various commonly used ceramics can be used. Examples of such ceramics include alumina ceramics, silicon carbide ceramics, beryllium oxide ceramics, and titanium / barium titanate ceramics.

The coating material applied to the substrate contains a copper salt or a silver salt dissolved or suspended in a medium. The anion constituting the salt may be an inorganic anion or an organic anion as long as it has no effect on the reaction in which the copper salt or the silver salt changes into a metal or its oxide during the firing process. Examples of such inorganic anions include anions such as sulfide ions (S ²⁻ ), halogen ions (eg Cl ⁻ ), sulfate ions, nitrate ions and the like. Particularly, sulfide ion is preferable. Also, as the organic anion,
For example, acetate ion, formate ion, citrate ion,
Examples thereof include gluconate ion and oxalate ion. Particularly, citrate ion is preferable. Preferably, a copper salt,
The silver salt is used as a mixture. In this case, the amount of copper salt is 20-80% by weight, preferably 40-80% by weight, based on the weight of the mixture. When the amount of the copper salt is less than 20% by weight, the catalytic ability of the silver salt becomes too strong, and for example, the electroless copper plating treatment becomes vigorous, resulting in rough plating, which is not preferable. On the other hand, the amount of copper salt is 8
When it is more than 0% by weight, the adhesion to the raw material tends to decrease, which is also not preferable.

The copper salt or silver salt is used in a state of being dispersed or dissolved in a medium in order to improve coating efficiency and enable coating with a uniform thickness. As the medium, for example, water or an organic solvent can be used. Examples of the organic solvent that can be used include aromatic solvents such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, and alcohols such as methyl alcohol and ethyl alcohol. The amount of the solvent used is usually 10 to 40% by weight, preferably 20 to 30% by weight, based on the solid content of the coating material (the amount of copper salt or silver salt). When the concentration is lower than 10% by weight, the coating film tends to be non-uniform, which is not preferable. On the other hand, the concentration is 40
When the content is higher than the weight%, it tends to be difficult to apply, which is also not preferable. The paint containing the copper salt or silver salt preferably has a viscosity suitable for coating.
For example, the viscosity of the paint is usually 50-300 ps, preferably
150 to 200 ps is suitable. If necessary, the paint may contain a salt of a metal such as nickel, palladium, or platinum as a catalyst for electroless plating or electrolytic plating. Examples of the nickel salt include nickel chloride, nickel sulfate, nickel sulfamate and the like. Examples of the palladium salt include palladium sulfide, palladium chloride, palladium sulfate, palladium nitrate and the like. Furthermore, examples of the platinum salt include platinum chloride, potassium thiocyanate platinum, platinum sulfate, and the like. These metal salts generally have a metal concentration of
It can be used in an amount of 1 to 200 ppm, preferably 10 to 100 ppm. Furthermore, various additives such as a thickener, an adhesive, and a photosensitizer can be added to the paint, if necessary. The coating of the paint on the surface of the substrate can be performed by various printing methods such as gravure printing and screen printing. The paint generally has a thickness of 0.01 to 10 μm after drying.
The coating is preferably 0.1 to 1 μm.

After applying the above paint to the substrate, for example, 8
0 to 160 ° C, preferably 100 to 130 ° C, 1 to 3
After drying for 0 minutes, preferably 5 to 15 minutes, baking is performed.
The calcination needs to be at a temperature sufficient to change the copper salt or silver salt into a metal or its oxide by heating. The firing temperature is usually 300 to 70.
It is 0 ° C., preferably 400 to 600 ° C. The firing time varies depending on the firing temperature, but is preferably 5 to
60 minutes, particularly preferably 10 to 30 minutes.

As the electroless plating treatment, the electroless plating treatment conventionally used when forming electrodes and wirings on such a substrate can be used without limitation. An example of typical electroless plating includes electroless copper plating. The electroless copper plating method is preferably carried out under the following conditions. 1. Bath composition concentration Copper sulfate 0.04 to 0.05 mol / l EDTA.4Na 0.08 to 0.10 mol / l Formalin 0.06 to 0.12 mol / l Additive Some 2. pH: 11.8 to 12.5 3. Temperature: 20-75 ° C, preferably 25-45 ° C 4. Plating treatment time: 5 to 30 minutes, preferably 10 to 20 minutes As an additive in the bath composition, for example, 2,2'-
Stabilizers such as dipyridyl and polyethylene glycol (PEG), and other additives conventionally used in such electroless plating can be used without limitation.

As the electroplating treatment, the electroplating treatment conventionally used when forming electrodes, wirings and the like on such a substrate can be used without limitation.
An example of a typical electrolytic plating is electrolytic copper plating. As the electrolytic copper plating method, preferably,
Examples include those performed under the following conditions. 1. Bath composition concentration Copper sulfate 50 to 80 g / liter Sulfuric acid 150 to 210 g / liter Cl ^- 30 to 70 ppm Additive Some 2. Temperature: 10-45 ° C, preferably 20-30 ° C 3. Current density: 0.3 to 5 A / dm ² , preferably 0.5 to 3 A / dm ² Note that electrolytic plating may be performed after electroless plating.

[0011]

The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. Example 1 A paint (xylene concentration: 30%, viscosity: 30) containing copper sulfide and silver sulfide in a ratio of 50:50 (weight ratio) on a 10 cm × 10 cm (plate thickness: 1 mm) soda-lime glass substrate.
The film thickness after drying is 0.1 ps) by screen printing.
It was coated to a thickness of μm and dried at 120 ° C. for 1 hour.
Then, after baking the substrate at about 550 ° C. for 15 minutes, the following steps were performed. Treatment process conditions Alkaline degreasing process 80 ° C, 5 minutes Water washing process room temperature, 1 minute Electroless plating process 25 ° C, 10 minutes Water washing process room temperature, 1 minute 10% sulfuric acid Room temperature, 1 minute Water washing process room temperature, 1 minute Copper sulfate plating 25 ° C 2A / dm ² , 70 minutes water washing step room temperature, 1 minute Discoloration prevention step room temperature, 20 seconds water washing step room temperature, 1 minute drying step

The bath composition in the electroless plating step is as follows. Component concentration Copper sulfate 0.05 mol / liter EDTA ・ 4Na 0.01 mol / liter formalin 0.08 mol / liter Stabilizer 2,2'-dipyridyl 10 ppm PEG 10 ppm (pH adjusted to 11.8 to 12.5 with NaOH aqueous solution) Discoloration The prevention step is a treatment for preventing the formed copper surface from being oxidized, and is a step of immersing in a solution of a nitrogen-containing heterocyclic compound such as benzotriazole or imidazole. The solution is generally a 0.5-1% solution.

The adhesion of the obtained copper-plated layer was determined by cutting the copper film with a knife at 1 cm ² to 1 mm square, attaching a cellophane tape, and then pulling the cellophane tape uprightly just above the film to attach it. It was evaluated by measuring the amount (tape peel test). As a result, the adhesion between the substrate and the copper film was very strong, and the adhesion between the substrate and the plating layer was very good. Comparative Example 1 A 10 cm × 10 cm (plate thickness: 1 mm) soda-lime glass substrate was formed with a copper plating film by a conventional electroless plating method including the following steps. However, the pattern formation by the resist and its removal step are omitted for convenience. In practice, these steps are required to form a patterned copper plating film. Treatment process condition Etching treatment process Room temperature, 5 minutes (Nitric acid 200 ml / l, Hydrofluoric acid 200 ml / l) Water washing process Room temperature, 1 minute Sensitizing process Room temperature, 5 minutes (First tin chloride 10 g / l) Water washing process Room temperature, 1 minute Activating step Room temperature, 5 minutes (Palladium chloride, 0.2 g / l) Water washing step Room temperature, 1 minute Electroless plating step 25 ° C, 10 minutes (same conditions as in Example 1) Water washing step Room temperature, 1 Min. Copper sulfate plating 25 ° C, 2 A / dm ² , 70 minutes Water washing step Room temperature, 1 minute Discoloration prevention step Room temperature, 20 seconds Water washing step Room temperature, 1 minute Drying step Electroless plating film is used as a base material in a copper sulfate plating bath. It has come off the glass surface.

Example 2 2.54 cm × 2.54 cm (plate thickness: 0.063 cm)
Except that the alumina ceramics of
A circuit board was manufactured in the same manner as in Example 1. When the adhesion of the obtained copper plating layer was measured by a tape peeling test in the same manner as in Example 1, the adhesion between the substrate and the copper plating film was very strong, and the plating layer was peeled off by the tape. There was no.

Comparative Example 2 A conventional electroless plating process was performed on the 10 cm × 10 cm (plate thickness: 1.6 mm) alumina ceramic substrate by the following steps. As in Comparative Example 1, for convenience, the patterning process using a resist and the removal process thereof were omitted. Treatment process conditions Alkaline degreasing process 60 ° C, 5 minutes Water washing process room temperature, 1 minute Alkaline treatment process 135 ° C, 10 minutes (500g / liter NaOH) Water washing process room temperature, 1 minute Etching process 65 ° C, 30 minutes (200g / liter acidic foot Room temperature, 1 minute Antimony) Water washing step Room temperature, 1 minute Catalyzing step 35 ° C, 3 minutes (Pd-Sn alloy colloid) Water washing step Room temperature, 1 minute Accelerating step 50 ° C, 5 minutes (Sn removal, Pd removal) Exposure treatment) Water washing step Room temperature, 1 minute Electroless plating step 25 ° C, 10 minutes Water washing step Room temperature, 1 minute 10% Sulfuric acid treatment Room temperature, 1 minute Water washing step Room temperature, 1 minute Copper sulfate plating treatment 25 ° C, 2 A / dm ² , 70 minutes water washing step room temperature, 1 minute drying step The adhesiveness of the obtained copper plating layer was measured by a tape peeling test in the same manner as in Example 1, and it was found that the copper plating layer was 50 Or peels off, sufficient adhesion was not obtained.

[0016]

According to the present invention, there is provided a method for forming a plating layer having excellent adhesion between a glass or ceramic substrate and the plating layer. Further, in the present invention, masking treatment with a resist, etching treatment in pattern formation, and further, catalyst activation treatment are unnecessary, and the manufacturing method is greatly simplified as compared with the conventional conductive layer forming method. It becomes a thing.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H05K 3/18 H01L 21/88 B (56) Reference JP-A-60-195077 (JP, A) JP-A-57-39166 ( JP, A) JP 5-239657 (JP, A) JP 4-272182 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 18/18 C25D 5/54 C25D 7/00 H01L 21/288 H01L 21/3205 H05K 3/18

Claims (2)

(57) [Claims] 1. Plating on a glass or ceramic substrate, characterized in that a coating containing an inorganic silver salt and a copper salt is coated on a glass or ceramic substrate, dried and baked, and then electroless plating is performed. Method of forming layer. 2. A glass or ceramic substrate, characterized in that a coating containing an inorganic silver salt and an inorganic copper salt is applied onto a glass or ceramic substrate, dried and baked, and then electroless plating is performed. Method of forming plating layer.