JPH09186432A - Production of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a printed wiring board easily and inexpensively while shortening the production process. SOLUTION: A UV-curing insulating resin layer 2 is formed on an insulating board 1 and cured by irradiating with UV-rays 4 except the part for forming a conductor 8. Subsequently, only the part of insulating resin layer 2 for forming a conductor 8 is roughened and a plating catalyst 5 is bonded to the roughened part. Finally, a conductor 8 is formed by electroless plating.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a printed wiring board.

[0002]

2. Description of the Related Art Conventionally, a printed wiring board is generally manufactured by a subtractive method. This manufacturing method uses a copper-clad insulating substrate, forms electroless plating and electrolytic plating on the surface, forms through-hole plating, and then forms a conductor circuit by etching away copper other than the conductor circuit. To do. Since this manufacturing method uses the copper-clad insulating substrate, no special treatment is required to secure the adhesion strength between the circuit and the insulating substrate, and the circuit is provided with electrolytic plating on the copper foil surface. Therefore, it has the advantage of being highly reliable. Further, as another manufacturing method, there is an additive method in which an insulating substrate provided with an adhesive layer without copper plating is used and electroless plating is performed to form a conductor circuit. In this manufacturing method, the circuit can be formed by performing electroless copper plating treatment only on the necessary portions, and therefore the manufacturing process is shortened.

[0003]

However, the former subtractive method has a drawback that unnecessary copper other than the circuit must be removed, etching is required, and the number of manufacturing steps is increased. In the latter additive method, an insulating substrate containing a special adhesive layer and containing a plating catalyst must be used, which has a drawback of high material cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a printed wiring board, which improves the above drawbacks, has a short manufacturing process, and can be manufactured easily and inexpensively.

[0005]

According to the present invention, there is provided a step of forming an ultraviolet curing type insulating resin layer on a surface of an insulating substrate, and irradiating an ultraviolet ray to a portion other than a conductor to be formed after this step to irradiate the insulating layer. A step of curing the resin layer, a step of roughening only the portion of the insulating resin layer on which the conductor is formed after this step, and a step of attaching a plating catalyst to the roughened portion of the insulating resin layer after this step And a step of forming the conductor by performing electroless plating after this step.

According to the present invention, a circuit-shaped conductor can be formed without using a copper-clad insulating substrate, and an etching process and a process associated therewith are not required, and the manufacturing is relatively easy and the manufacturing cost is reduced. it can. Further, it is not necessary to use an insulating substrate peculiar to the full additive method, and a commonly used laminated board can be used as a base insulating substrate, and a relatively inexpensive printed wiring board can be obtained.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the insulating substrate of the present invention, a paper epoxy resin laminated plate, a paper phenol resin laminated plate, a glass epoxy resin laminated plate or the like is used. Then, on the surface of this insulating substrate, an ultraviolet curable type, such as a curtain coat method,
An insulating resin containing epoxy resin or nitrile butadiene rubber as a component is applied to form an insulating resin layer. Then, a negative film having a reverse pattern of a conductor is applied to the surface of this insulating resin layer to form a mask, which is then irradiated with ultraviolet rays. After irradiation with ultraviolet rays, the insulating resin layer is roughened using a roughening liquid. At this time, the portion of the insulating resin layer irradiated with ultraviolet rays is hardened and is not roughened, and the uncured portion which has been masked and is not irradiated with ultraviolet rays is roughened. After roughening, a plating catalyst is applied to the surface of the insulating resin layer using a plating catalyst treatment liquid. Note that the plating catalyst does not adhere to the smooth surface of the insulating resin layer that is not roughened, but catches and adheres to the roughened surface. After adhering to the plating catalyst, electroless copper plating is performed using an electroless copper plating solution having a composition such as copper sulfate or EDTA to deposit copper plating on the roughened surface of the insulating resin layer to which the plating catalyst is attached. To form a conductor.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1A, 1 is an insulating substrate, and a glass epoxy resin laminated plate E-67 (trade name, manufactured by Hitachi Chemical Co., Ltd.) is used.

Then, as shown in FIG. 1B, an ultraviolet curable insulating resin is applied to both surfaces of the insulating substrate 1 by a curtain coating method to form an insulating resin layer 2. This UV-curable insulating resin layer 2 is composed of acrylic modified epoxy resin 50 wt%, nitrile butadiene rubber 35 wt%,
Calcium carbonate 10 wt%, imidazole-based curing agent 5 wt%
Consists of

Next, after drying at a temperature of 80 ° C. for 30 minutes,
As shown in FIG. 1C, the negative film of the reverse pattern of the conductor is used as the mask 3 and is applied to the surface of the insulating resin layer 2, and an ultraviolet ray 4 is insulated with a light amount of 1 J / cm ² by using an exposure device having an ultrahigh pressure mercury lamp. The resin layer 2 is irradiated.

After irradiating with ultraviolet rays 4, the insulating substrate 1 is swelled with a liquid OPC-1050 (trade name of Okuno Pharmaceutical Co., Ltd.),
The surface of the insulating resin 2 is roughened by sequentially immersing it in a roughening solution OPC-1200 (trade name of Okuno Pharmaceutical Industry Co., Ltd.) and a neutralizing solution OPC-1300 (trade name of Okuno Pharmaceutical Industry Co., Ltd.). At this time, as shown in FIG. 1D, the portion of the insulating resin layer 2 which is irradiated with ultraviolet rays is not roughened, and only the portion which is not irradiated by the mask 3 is roughened.

After the roughening treatment, the insulating substrate 1 was immersed in a catalyst treatment liquid HS-201B (trade name of Hitachi Chemical Co., Ltd.) having a concentration of 6 ml / l for 5 minutes for electroless plating to give a plating catalyst. Adhere to. At this time, the plating catalyst 5 is as shown in FIG.
As shown in (3), it adheres only to the roughened surface 6 of the insulating resin layer 2 and does not adhere to the smooth surface 7.

After depositing the plating catalyst, the insulating substrate 1 is heated to a temperature of 7
The printed wiring board 9 is formed by immersing in an electroless copper plating solution at 0 ° C., depositing copper plating on the roughened surface 6 to form a conductor 8 as shown in FIG. The composition of the electroless copper plating solution was copper sulfate pentahydrate 0.04 mol / l, sodium hydroxide 0.05 mol / l, 37% formaldehyde aqueous solution 0.04 mol / l, ethylenediaminetetraacetic acid 0.15 mol.
/ L, α, α'-dipyridyl 30 mg / l, and polyethylene glycol (molecular weight 1000) 1 g / l.

[0014]

As described above, according to the manufacturing method of the present invention, an ultraviolet-curing type insulating resin layer is formed on the surface of an insulating substrate, and a portion other than a conductor is ultraviolet-cured, and this portion is roughened. Since a conductor is formed by electroplating, applying a plating catalyst, and forming a conductor by electroless plating, an inexpensive printed wiring board can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing process according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Insulating substrate, 2 ... Insulating resin layer, 4 ... Ultraviolet ray, 5
... plating catalyst, 6 ... roughened surface, 8 ... conductor, 9 ... printed wiring board.

Claims (1)

[Claims] 1. A step of forming an ultraviolet curable insulating resin layer on the surface of an insulating substrate, and a step of irradiating the portion other than the conductor to be formed with ultraviolet rays after this step to cure the insulating resin layer. After this step, a step of roughening only the portion of the insulating resin layer on which the conductor is formed, a step of attaching a plating catalyst to the roughened portion of the insulating resin layer after this step, and an electroless plating after this step And a step of forming the conductor by processing.