JPH0245347B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a printed circuit board which is subjected to chemical plating using, for example, an additive method. Conventionally, printed circuit boards are made by cutting out a desired shape from a copper-clad laminate, drilling holes for connecting parts, etc., and then applying photoresist, ink resist, etc. to the processed laminate to form the desired electrical circuit. After printing a corresponding pattern and curing it by heating to form an acid-resistant resin layer, the layer is immersed in a ferric chloride aqueous solution or other suitable etching solution, and the exposed copper foil portion is removed by etching. ing. However, with this method, the required copper clad part (circuit layer) is usually 10 to 10% of the area of the initial copper clad laminate.
Only about 40% of the etching solution is occupied by the etching solution, and the remaining part is removed by etching, resulting in an economic loss and requiring a large amount of processing cost when discharging the etching solution. Conventionally, in order to improve such drawbacks, the special public
11354, a so-called additive method has been implemented in which a desired circuit layer is selectively formed by chemical plating or chemical plating and electroplating on an insulating substrate. However, in the conventionally proposed methods, in order to increase the adhesion between the circuit layer and the insulating substrate, it is necessary to form an adhesive layer such as varnish made of nitrile rubber and phenolic resin on the insulating substrate. This is necessary, and there has been a demand for simplification of processes such as varnish application and curing processes. Furthermore, the above-mentioned method also has insufficient adhesion between the circuit layer and the insulating substrate, and improvements in this have been desired. The present inventors have conducted various studies with the aim of providing a method for manufacturing printed circuit boards that does not require an adhesive layer and that also has high adhesion between the circuit layer and the insulating substrate when manufacturing printed circuit boards using the additive method. As a result, the present invention was completed. That is, the present invention comprises 0.1 to 40 parts by weight of an alkaline earth metal carbonate, 98.9 to 20 parts by weight of a resin selected from the group consisting of polyether sulfone, polyphenylene sulfide, and polyether ether ketone, and fibrous reinforcement. The object of the present invention is to manufacture a printed circuit board in which a conductive metal wiring pattern is additionally formed on a substrate formed by forming a resin composition comprising 1 to 40 parts by weight of a metal. Examples of alkaline earth metal carbonates include CaCO ₃ ,
MgCO ₃ , SrCO ₃ , BaCO ₃ , CaMg(CO ₃ ) _{2 ,} etc. can be used, but in order to increase the adhesion between the circuit layer and the insulating substrate, especially CaCO ₃ and/or CaMg
Preference is given to using (CO ₃ ) ₂ . The amount of alkaline earth metal carbonate used must be in the range of 0.1 to 40 parts by weight based on 100 parts by weight of the resin composition; if it is less than 0.1 part by weight, adhesion cannot be obtained; Above this, the electrical properties of the insulating plate deteriorate. Therefore, a particularly preferred range is 5 to 20 parts by weight. The resin used in the present invention is polyether sulfone,
It is any resin selected from the group consisting of polyphenylene sulfide and polyetheretherketone. These resins have high adhesion between the circuit layer and the insulating substrate. The fibrous reinforcing material is glass fiber, carbon fiber, etc., and is necessary for reinforcing the mechanical strength of the insulating substrate. If the fibrous reinforcing material is less than 1 part by weight, the reinforcing effect will not be sufficient, and if it exceeds 40 parts by weight, the surface of the board obtained by molding the resin composition will not be smooth and the circuit layer and board will not adhere well. Power decreases. From this point of view, the preferred range is 5 to 20 parts by weight. A substrate formed by molding the above-described resin composition of the present invention can be easily produced by a known method, that is, by mixing and kneading alkaline earth metal carbonate, resin, and glass fiber using a kneader such as an extruder. It can be manufactured to In the present invention, in order to form a circuit layer of a printed circuit board from an insulating substrate made of a resin composition, there are two known methods, namely, a method of forming a conductive pattern only by chemical plating, and a method of forming a conductive pattern by chemical plating and electroplating. A method of forming a circuit layer using a combination of processing is adopted. That is, first, compression molding of the resin composition of the present invention,
After forming into a plate shape by extrusion molding or the like, it is cut out and punched into a desired shape, or it is formed into a desired shape by injection molding. After that, use a normal oxidizing conditioning solution such as a chromic acid mixture to 50-70%
Conditioning is carried out under normal conditions at ℃. However, in order to form a circuit layer only by chemical plating, a resist pattern is provided so that the desired circuit pattern is exposed before or after the conditioning process, and then chemical plating is applied to the desired thickness. . On the other hand, in the method of forming a circuit layer using a combination of chemical plating and electroplating, a thin chemical plating layer is applied to the entire surface of the resin plate after the conditioning step, and this chemical plating layer is coated with a thin chemical plating layer. The chemical plating layer is exposed on the desired circuit pattern through a mask, etc., and then a sufficiently thick metal layer is applied to the circuit portion by electroplating, and finally the unnecessary resist and chemical plating layer are removed. By removing it, a circuit layer can be formed. Examples will be described below. Examples 1 to 5 The resin compositions shown in the table were prepared and molded by injection molding.
Formed into a board of 150m/m x 150m/m x 1.5m/m,
Conditioning was performed using the conditioning solution shown below. Concentrated sulfuric acid 520 parts Water 720 parts Chromium trioxide 440 parts After washing the board with water, copper plating was performed by chemical plating and electroplating to an average thickness of 30 microns according to conventional methods, and the surface was coated with copper. was prepared, and the adhesion strength, solder heat resistance, and volume resistivity of the plate were measured according to the method described in JIS-C-6481-6483. The evaluation results are shown in the table, and it was found that the performance as a printed circuit board was satisfied and was sufficiently durable for practical use. Comparative Examples 1-2 Comparative Examples 1-2 were prepared in the same manner as Examples 1-5 except that the composition of the resin composition was changed as shown in the table.
A circuit board was fabricated. Next, the results were evaluated in the same manner as in Examples 1 to 5, and the results are shown in the table. Comparative example 1 not containing alkaline earth metal carbonate
has poor adhesion, and carbonates of alkaline earth metals are
Comparative Example 2 containing parts by weight has a lower volume resistivity. Comparative Examples 3 and 4 The resin compositions shown in the table were prepared and molded by compression molding.
Form a board of 150m/m x 150m/m x 1.5m/m,
Example

[Table] A circuit board was produced by the same operations as in 1 to 5. Next, evaluations were made in the same manner as in Examples 1 to 5, and the results are shown in the table. All of them were slightly inferior in adhesion strength and volume resistivity.

Claims (1)

[Scope of Claims] 1. 5 to 20 parts by weight of an alkaline earth metal carbonate, 90 to 60 parts by weight of a resin selected from the group consisting of polyether sulfone, polyphenylene sulfide, and polyether ether ketone, and fibrous A method for manufacturing a printed circuit board, comprising forming a conductive metal wiring pattern on a substrate formed by molding a resin composition containing 5 to 20 parts by weight of a reinforcing material. 2. The method according to claim 1, wherein the alkaline earth metal carbonate is calcium carbonate. 3. The method according to claim 1, wherein the alkaline earth metal carbonate is CaMg(CO ₃ ) ₂ . 4. The method according to claim 1, wherein the alkaline earth metal carbonate is a mixture of calcium carbonate and CaMg( _CO3 ) ₂ .