JPH06334313A - Manufacture of circuit board - Google Patents

Abstract

PURPOSE:To form a conductor pattern by few processes as compared with the conventional technique for forming electrodes by chemical plating, by a method wherein organic metal paste is spread on a ceramic board, and a conductor film is formed by an electrolytic plating method applying an organic metal film obtained by baking to an electrode. CONSTITUTION:Organic metal paste 12 is spread on an alumina board 10 by using a screen printing method, so as to connect all conductor patterns, excepting parts needing no conductor. Gold conductor 12 is formed by drying and baking the paste 12. A photosensitive dry film is stuck on the formed gold conductor 12 and resist 14 exposing only the necessary part of the gold conductor 12 is formed. After that, the board 10 on which resist 14 is formed is subjected to electrolytic plating of copper, and a copper conductor film 16 is formed only on the necessary part. The resist 14 is peeled, and the board 10 wherein the resist 14 is peeled is dipped in iodine-potassium iodide solution. Thereby an unnecessary substratum electrode is eliminates and a desired conductor pattern is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a circuit board used in electronic equipment, and more particularly to a method of manufacturing a wiring board having a wiring pattern formed on a ceramics substrate.

[0002]

2. Description of the Related Art Conventionally, a circuit board having a circuit formed on a ceramic substrate has been widely used in electronic devices and the like. As one of the circuit boards, a desired conductor pattern for transmitting a signal is formed. A printed wiring board may be used. Conventionally, this wiring board is manufactured by forming a conductor film on the ceramics substrate by plating, etc., but conventionally, by performing chemical etching treatment, seeding treatment and then chemical plating on the ceramics substrate, The conductor film was formed. Further, when forming a thick conductor film in a short time, electrolytic plating is performed using the conductor formed by chemical plating as an electrode. After forming the conductor film in this manner, a resist is formed so that only the unnecessary portion is exposed, and the unnecessary portion is removed by etching to obtain a desired conductor pattern.

[0003]

The above-mentioned conventional method has the following problems. (1) In order to form a base electrode required for electroplating by chemical plating, pretreatment such as chemical etching treatment or seeding treatment is necessary for the substrate in advance. (2) It takes time to form the base electrode by chemical plating. (3) Since the chemical plating has no selectivity, a conductive film adheres to the entire surface of the substrate and must be removed later, which results in a large waste of materials.

In view of the above circumstances, it is an object of the present invention to provide a method for manufacturing a circuit board, which allows a circuit board to be manufactured at low cost by easily forming a base electrode required for electroplating. .

[0005]

The present invention for achieving the above object provides a circuit board manufacturing method for manufacturing a circuit board in which a conductor film is formed on a ceramics substrate.
Characterized in that an organometallic paste is applied on a ceramic substrate and fired, and the organometallic film formed by this firing is used as an electrode to form a conductor film on the organometallic film by electroplating. Is.

Here, it is preferable to apply the organometallic paste in a desired pattern on the ceramic substrate by screen printing. Further, as one aspect of the present invention, in a circuit board manufacturing method for manufacturing a circuit board in which a conductor film is formed on a ceramics substrate, an organic metal paste containing gold as a metal component is applied onto the ceramics substrate. By firing, a resist having a desired region exposed is formed on the organometallic film formed by this firing, and the organometallic film is used as an electrode on the desired region of the organometallic film by electroplating. A method of forming a copper conductor film, removing the resist, and immersing the resist film in an iodine-potassium iodide solution to remove the organometallic film formed in the region other than the desired region may be adopted. .

[0007]

FUNCTION The organometallic paste is developed and commercially available for forming a dense film on a ceramic substrate. Therefore, when this material is used, no special pretreatment is required to form the base electrode on the ceramic substrate. Some commercially available organometallic pastes can be applied by screen printing. By using this, it is possible to obtain the electrical continuity of all the patterns required for electroplating without applying the conductor in advance to the unnecessary portions.

Further, a resist is formed on the gold base electrode so that only a necessary portion of the conductor is exposed, and a copper conductor is thickened by electroplating. After the resist is peeled off, it is immersed in an iodine-potassium iodide solution to remove unnecessary portions of the base electrode and obtain a desired conductor pattern. Because of this, the circuit board can be manufactured at low cost.

[0009]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a schematic perspective view of a circuit board showing each step of an embodiment of a method for manufacturing a circuit board of the present invention. 50.8 x 5
Organometallic paste 12 (GB-1003; Tanaka Kikinzoku Co., Ltd.) was applied on an alumina substrate 10 having a thickness of 0.8 mm and a thickness of 0.635 mm by screen printing so as to connect all conductor patterns except unnecessary portions of the conductor. International Co., Ltd.) was applied. This in a dryer 12
Dry at 0 ° C for 10 minutes, and in a belt-type continuous firing furnace in air,
Firing was performed under conditions of 810 ° C. and 5 minutes to form a gold conductor 12 having a thickness of about 0.7 μm (FIG. 1 (A)).

A photosensitive dry film was adhered on the gold conductor 12 formed as described above, and a resist 14 was formed by a photographic method so that only a necessary portion of the gold conductor 12 was exposed (see FIG. 1 ( B)). Then, on the alumina substrate 10 on which the resist 14 is formed, electrolytic plating of copper is performed under the conditions of copper sulfate of 200 g / liter and current density of 33 mA / cm ² , and a copper conductor film 16 having a thickness of about 35 μm is formed only on a necessary portion. Formed (FIG. 1 (C))).

After that, the resist 14 is peeled off, and the alumina substrate 10 from which the resist 14 is peeled off is dipped in a solution of 300 cc of water containing 200 g of iodine and 100 g of potassium iodide for 30 seconds to remove unnecessary base electrodes. Then, a desired conductor pattern was obtained (FIG. 1 (D)).

[0012]

As described above, according to the present invention, the organic metal paste is applied on the ceramic substrate and fired, and electroplating is performed using the organic metal film formed thereby as an electrode. The conductive pattern is formed in a smaller number of steps as compared with the conventional method of forming an electrode by the method, whereby the circuit board is manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a circuit board showing each step of an embodiment of a method for manufacturing a circuit board of the present invention.

[Explanation of symbols]

 10 Alumina substrate 12 Organic metal paste 14 Resist 16 Copper conductor film

Claims (3)

[Claims] 1. A method of manufacturing a circuit board for manufacturing a circuit board in which a conductor film is formed on a ceramics substrate, wherein an organic metal paste is applied onto the ceramics substrate and baked, and the organic metal formed by this baking. A method for manufacturing a circuit board, which comprises using a film as an electrode and forming a conductor film on the organometallic film by electroplating. 2. The method for manufacturing a circuit board according to claim 1, wherein the organometallic paste is applied in a desired pattern on the ceramic substrate by screen printing. 3. A circuit board manufacturing method for manufacturing a circuit board in which a conductor film is formed on a ceramics substrate, wherein an organic metal paste containing gold as a metal component is applied onto the ceramics substrate and baked, A resist in which a desired region is exposed is formed on the organometallic film formed by baking, and the organometallic film is used as an electrode, and a copper conductor film is formed on the desired region of the organometallic film by electroplating. Is formed, and the resist is peeled off and immersed in an iodine-potassium iodide solution,
A method of manufacturing a circuit board, characterized in that the organometallic film formed in a region other than the desired region is removed.