JPH0964515A - Manufacturing method of printed wiring board - Google Patents

Abstract

(57) Abstract: In a method for manufacturing a printed wiring board in which a metal carrier on which a circuit pattern is formed is laminated with a prepreg and then the metal carrier is removed to form an outermost layer circuit pattern, a circuit pattern plating resist To prevent the circuit pattern from being cut or scratched when the metal carrier is routed by roughening the circuit pattern, etc. to improve product quality and reliability. . SOLUTION: a. Applying a thin copper plating to the metal carrier, b. A non-peelable permanent plating resist covering a portion other than the circuit pattern is applied to this copper plating layer, and c. Thick copper plating is applied to the coating surface of the plating resist to form a circuit pattern, and d. Roughening the surface of this circuit pattern; e. Stacking prepregs, f. Peel off the metal carrier, g. The unnecessary portion of the thin copper plating is removed by etching. As the permanent plating resist, a photocurable resist can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board in which a prepreg is laminated on a circuit pattern formed on a metal carrier and then the metal carrier is peeled off to form an outermost layer circuit pattern.

[0002]

2. Description of the Related Art A so-called transfer method is known as a method for forming an outermost layer circuit pattern of a printed wiring board. In this method, a circuit pattern is formed on one surface of a metal plate (called a metal carrier), a prepreg is laminated on this surface, and the metal carrier is peeled off.

FIG. 2 is a diagram showing the steps of this conventional method. In FIG. 2, reference numeral 10 is a metal carrier, for example, a stainless plate is used. A thin copper plating 12 is applied to one surface of the metal carrier 10, and a region other than the circuit pattern is a peeling type plating resist 1.
4 (FIG. 2 (A)).

The plating resist 14 may be formed by applying a peeling type plating resist ink by screen printing. The plating resist 14 can be easily peeled off with a peeling solution such as an alkaline aqueous solution or trichloroethylene or trichloroethane.

A thin coating 16A of Ni, Au, or the like is applied to the coated surface of the plating resist 14 for etching resistance, and a thick copper plating 16B is applied thereon, and the circuit pattern is formed by these copper plating layers 16A and 16B. 16 is formed ((B) of FIG. 2). Then, when the plating resist 14 is peeled off using a peeling solution, the circuit pattern 16 remains ((C) of FIG. 2).

After roughening the surface of the circuit pattern 16, a prepreg 18 is laminated on this surface ((D) of FIG. 2). This roughening treatment is performed to increase the adhesion between the circuit pattern 16 and the prepreg 18 and increase the bonding strength. It goes without saying that a laminated board having an inner layer circuit pattern may be used instead of the prepreg 18. In (D) of this figure, 20 is a back plate for pressurizing by a press machine.

After laminating the prepreg 18 or the laminated plate in this manner, the metal carrier 10 is peeled off ((E) of FIG. 2). Since the metal carrier 10 is made of a material such as stainless steel which has a weak bonding strength with the copper plating 12,
The metal carrier 10 can be easily peeled off from the copper plating 12. After peeling off the metal carrier 10, an unnecessary portion (12A) of the copper plating 12, that is, the circuit pattern 1
Parts other than 6 are removed by etching. As a result, the printed wiring board 22 is completed.

[0008]

Problems of the Prior Art This conventional method has the following three problems. First, as shown in FIG. 3, the bonding between the plating resist 14 and the thin copper plating 12 is weak, and the plating resist 14 easily floats from the thin copper plating 12. Therefore, when the circuit pattern 16 is thickly plated with copper, the plating solution enters the floating gap,
Intrusion into the non-circuit pattern portion of the circuit pattern 16 occurs. Reference numeral 16C in FIG. 3 shows this recessed portion. The presence of the recessed portion 16C easily causes a short circuit in the circuit pattern 16.

The second problem is that when the surface of the circuit pattern 16 is roughened, the circuit pattern 16 is easily broken or damaged. This roughening is performed by a chemical treatment, but since the circuit pattern 16 is in a state of protruding on one surface of the metal carrier 10, it is easily scratched if something touches this surface.

A third problem is that air bubbles easily enter near the root of the circuit pattern 16 (near the arrow A in FIG. 2) when the prepreg 18 is laminated. These first, second, and third problems all cause deterioration of product quality and reliability.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a method for manufacturing a printed wiring board which is free from the problems described above and which can improve product quality and reliability. The purpose is to provide.

[0012]

According to the present invention, the object is to provide a method for manufacturing a printed wiring board in which a metal carrier having a circuit pattern is laminated with a prepreg and then the metal carrier is removed to form an outermost layer circuit pattern. Applying a thin copper plating to the metal carrier, b. A non-peelable permanent plating resist covering a portion other than the circuit pattern is applied to this copper plating layer, and c. Thick copper plating is applied to the coated surface of the plating resist to form a circuit pattern, and d. Roughening the surface of this circuit pattern, e. Laminating prepregs, f. Peel off the metal carrier, g. An unnecessary part of thin copper plating is removed by etching, which is achieved by a method for manufacturing a printed wiring board. As the permanent plating resist used here,
A photo-curable type can be used.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a process drawing of an embodiment of the present invention. First, as in the case described with reference to FIG. 2, a thin copper plating 12 is applied to the metal carrier 10, and a region other than the circuit pattern is non-peeling permanent plating resist 14.
Cover with A ((A) of FIG. 1).

Here, a non-peeling permanent plating resist 14 is used.
A can be formed, for example, by applying an ultraviolet (UV) curable or heat curable liquid resist ink by a screen printing method. Etching-resistant plating (eg Ni or Au) is applied to the coating surface of this plating resist 14A.
16A thinly plated, then thick copper plated 16B
Then, the circuit pattern 16 is formed by these plating layers ((B) of FIG. 1).

Next, the surface of the circuit pattern 16 is roughened by a chemical treatment ((C) of FIG. 1), and a prepreg 18 or a laminated plate having an inner layer circuit pattern is laminated (FIG. 1).
(D)). Then, after peeling off the metal carrier 10 and the back plate 20C of the pressing machine, thin copper plating 1
The unnecessary portion 12A of 2 is removed by etching (FIG. 1).
(E)). As a result, the printed wiring board 22A is completed.

Since the plating resist 14A used here is a non-peeling type and has a high bonding strength with the copper plating 12, the floating of the plating resist as described in FIG. 3 does not occur. Therefore, when the circuit pattern 16 is formed by thick copper plating, the plating solution does not enter below the plating resist 14A, and the circuit pattern 1
6 does not occur under the plating resist 14A.

Since the edge of the circuit pattern 16 is surrounded by the plating resist 14A, the circuit pattern 16 is protected by the plating resist 14A even if something touches the surface of the circuit pattern 16. Therefore, when roughening the surface of the copper-plated circuit pattern 16, the circuit pattern 1
There is no risk of breaking or scratching 6.

Further, since the circuit pattern 16 and the plating resist 14A are in close contact with each other, there is no room for bubbles to enter between them. Therefore, there is no possibility that air bubbles will enter the vicinity of the root of the circuit pattern 16 when the prepreg 18 and the laminated plates are laminated.

In this embodiment, the outermost layer circuit pattern 16 according to the present invention is formed on only one surface of the product, but it can be applied to the outermost layers on both surfaces. Further, it is needless to say that it can be applied to the outermost layer circuit pattern of the printed wiring board having the inner layer circuit pattern.

[0020]

As described above, according to the first aspect of the present invention, since the circuit pattern is formed on the metal carrier by using the non-peeling permanent plating resist, the circuit pattern does not go under the plating resist. . Further, since the circuit pattern is protected by the plating resist, the circuit pattern is not broken or scratched when the metal carrier is routed by the roughening treatment or the like.

Furthermore, since the periphery of the circuit pattern is filled with the plating resist, there is no possibility that air bubbles will enter the root of the circuit pattern when laminating the prepreg or another laminated plate. This improves product quality and reliability. The peelable permanent plating resist used here may be a photocurable permanent resist (claim 2).

[Brief description of drawings]

FIG. 1 is a diagram showing a process of the present invention.

FIG. 2 is a diagram showing steps of a conventional method.

FIG. 3 is a diagram for explaining the penetration of a circuit pattern by a conventional method.

[Explanation of symbols]

 10 Metal Carrier 12 Thin Copper Plating 14A Stripping Permanent Plating Resist 16 Circuit Pattern 18 Prepreg 22A Product

Claims (2)

[Claims] 1. A method for manufacturing a printed wiring board, which comprises forming a prepreg on a metal carrier having a circuit pattern and then removing the metal carrier to form an outermost layer circuit pattern. Applying a thin copper plating to the metal carrier, b. A non-peelable permanent plating resist covering a portion other than the circuit pattern is applied to this copper plating layer, and c. Thick copper plating is applied to the coated surface of the plating resist to form a circuit pattern, and d. Roughening the surface of this circuit pattern, e. Laminating prepregs, f. Peel off the metal carrier, g. A method for manufacturing a printed wiring board, comprising removing unnecessary portions of thin copper plating by etching. 2. The method for manufacturing a printed wiring board according to claim 1, wherein the non-peelable permanent plating resist is a photo-curable permanent resist.