Wiring board

Abstract

To provide a fine wiring conductor that is hardly peeled off from an insulating layer.SOLUTION: A wiring board of the present invention has a wiring conductor comprising an electroless plating layer and an electrolytic plating layer formed on an insulating layer, the wiring board having a recess facing the inside of the wiring conductor at a boundary portion between the electroless plating layer and the electrolytic plating layer. As a preferable embodiment, the recess is a substantially triangular recess, and the recess is formed of a first tapered part formed on the electrolytic plating layer and facing the inside from a side face of the wiring board toward the boundary portion, and a second tapered part formed on the electroless plating layer and facing the outside from the boundary portion toward the side face of the wiring board. As a preferable embodiment, the electroless plating layer is formed of electroless copper plating, and the electrolytic plating layer is formed of electrolytic copper plating.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wiring board having a wiring conductor made of an electroless plated layer and an electrolytic plated layer formed on an insulating layer. [Background technology]

[0002] Conventionally, various shapes of wiring boards have been known in which a wiring conductor made of an electroless plated layer and an electrolytic plated layer is formed on an insulating layer (for example, Patent Document 1). Fig. 3 is a diagram illustrating one embodiment of the wiring conductor in the wiring board disclosed in Patent Document 1. In Fig. 3, wiring board 51 has wiring conductor 55 made of electroless plated layer 53 and electrolytic plated layer 54 formed on insulating layer 52. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-181640 Summary of the Invention [Problem to be solved by the invention]

[0004] 3, the sidewall of electroless plated layer 53 tapers inward from the interface between electroless plated layer 53 and electrolytic plated layer 54 toward insulating layer 52. This reduces the contact area between electroless plated layer 53 and insulating layer 52, making it difficult for electroless plated layer 53 of wiring conductor 55 to peel off from insulating layer 52 when attempting to form fine wiring conductor 55. [Means for solving the problem]

[0005] The wiring board of the present invention is a wiring board having a wiring conductor consisting of an electroless plated layer and an electrolytic plated layer formed on an insulating layer, and has a recess facing inward of the wiring conductor at the interface between the electroless plated layer and the electrolytic plated layer. [Brief explanation of the drawings]

[0006] [Figure 1] 1A and 1B are diagrams illustrating an embodiment of a wiring conductor in a wiring board according to the present invention. [Figure 2A] 1A to 1C are diagrams illustrating an embodiment of a method for manufacturing a wiring conductor in a wiring board according to the present invention. [Figure 2B] 1A to 1C are diagrams illustrating an embodiment of a method for manufacturing a wiring conductor in a wiring board according to the present invention. [Figure 2C] 1A to 1C are diagrams illustrating an embodiment of a method for manufacturing a wiring conductor in a wiring board according to the present invention. [Figure 2D] 1A to 1C are diagrams illustrating an embodiment of a method for manufacturing a wiring conductor in a wiring board according to the present invention. [Figure 2E] 1A to 1C are diagrams illustrating an embodiment of a method for manufacturing a wiring conductor in a wiring board according to the present invention. [Figure 2F] 1A to 1C are diagrams illustrating an embodiment of a method for manufacturing a wiring conductor in a wiring board according to the present invention. [Figure 2G] 1A to 1C are diagrams illustrating an embodiment of a method for manufacturing a wiring conductor in a wiring board according to the present invention. [Figure 3] 10A and 10B are diagrams illustrating an embodiment of a wiring conductor in a conventional wiring board. DETAILED DESCRIPTION OF THE INVENTION

[0007] <About the wiring board according to the present invention> An embodiment of a wiring board according to the present invention will be described with reference to the drawings. In the example shown in Figure 1 and Figures 2A to 2G, the dimensions of each component, particularly the height dimension, are shown as dimensions different from the actual dimensions in order to better understand the features of the present invention.

[0008] Fig. 1 is a diagram illustrating one embodiment of a wiring conductor in a wiring board according to the present invention. In the example shown in Fig. 1, wiring board 1 of the present invention has wiring conductor 5 formed on insulating layer 2, which is composed of electroless plated layer 3 and electrolytic plated layer 4.

[0009] Wiring board 1 according to the present invention having the above-described configuration has recess 11 facing inward of wiring conductor 1 at interface B between electroless plated layer 3 and electrolytic plated layer 4. In a preferred embodiment, recess 11 is a substantially triangular recess in the example shown in FIG. 1 . Recess 11 is formed from first tapered portion 12-1 formed in electrolytic plated layer 4 and facing inward from the side surface of wiring board 1 toward interface B, and second tapered portion 12-2 formed in electroless plated layer 3 and facing outward from interface B toward the side surface of wiring board 1.

[0010] In the wiring board 1 according to the present invention shown in Fig. 1, a second tapered portion 12-2 is formed in the electroless plated layer 3 in the recess 11, facing outward from the interface portion B toward the side surface of the wiring board 1. The taper direction of this second tapered portion 12-2 is opposite to that of the tapered portion formed in the electroless plated layer in the prior art shown in Fig. 3. This increases the contact area between the second tapered portion 12-2 and the insulating layer 2, making it possible to form a wiring conductor 1 that is less likely to peel off from the insulating layer 2 than in the prior art.

[0011] 1 , in recess 11, electrolytic plated layer 4 is formed with first tapered portion 12-1 that faces inward from the side surface of wiring board 1 toward interface portion B. By forming first tapered portion 12-1 in electrolytic plated layer 4 in this manner, second tapered portion 12-2 can be formed so that the contact portion between electroless plated layer 3 and insulating layer 2 is located at the same position as the side surface of wiring conductor 1. This prevents second tapered portion 12-2 of electroless plated layer 3 from being positioned outward from the side surface of wiring board 1.

[0012] 1, recess 11 is formed from first tapered portion 12-1 formed in electrolytic plated layer 4 and facing inward from the side surface of wiring board 1 toward interface portion B, and second tapered portion 12-2 formed in electroless plated layer 3 and facing outward from interface portion B toward the side surface of wiring board 1. This makes it possible to obtain fine wiring conductors 5 that are not easily peeled off from insulating layer 2.

[0013] 1, the recess 11 is a substantially triangular recess, but in the present invention, it is not necessary to limit the shape of the recess 11 to a substantially triangular shape. In other words, it goes without saying that the recess 11 can have other shapes, such as an arch shape.

[0014] <About the manufacturing method of the wiring board according to the present invention> An embodiment of a method for manufacturing a wiring board according to the present invention will be briefly described with reference to FIGS. 2A to 2G. First, as shown in FIG. 2A, an electroless plated layer 3 is formed on the surface of insulating layer 2. Next, as shown in FIG. 2B, a resist layer 21 is formed on the surface of electroless plated layer 3. Next, as shown in FIG. 2C, to form openings 23 for forming wiring conductors 5, resist layer 21 is exposed and developed using mask 22. Then, as shown in FIG. 2D, a resist layer 21 having openings 23 is formed on electroless plated layer 3. In the present invention, protrusions 21a for forming first tapered portion 12-1 are formed in the portions of resist layer 21 that contact insulating layer 2 below openings 23. Next, as shown in FIG. 2E, an electrolytic plated layer 4 is formed within openings 23 of resist layer 21. Next, as shown in FIG. 2F, resist layer 21 is removed. Thereafter, as shown in FIG. 2G, the electroless plated layer 3 is etched away from the portions other than wiring conductors 5, thereby obtaining wiring board 1 according to the present invention. In the present invention, the presence of first tapered portion 12-1 of electrolytic plated layer 4 allows second tapered portion 12-2 to be formed in electroless plated layer 3 during etching. [Explanation of symbols]

[0015] 1. Wiring board 2. Insulation layer 3. Electroless plating layer 4. Electroplated layer 5 Wiring conductor 11. Depression 12-1 First tapered section 12-2 Second tapered section 21 Resist layer 21a protrusion 22 Mask 23 Aperture B Interface part

Claims

1. A wiring board having a wiring conductor formed on an insulating layer, the wiring conductor being made of an electroless plating layer and an electrolytic plating layer, A recess facing inward of the wiring conductor is formed at the interface between the electroless plated layer and the electrolytic plated layer.

2. 2. The wiring board according to claim 1, wherein the recess is a substantially triangular recess, and the recess is formed from a first tapered portion formed in the electroplated layer and facing inward from the side surface of the wiring board toward the interface portion, and a second tapered portion formed in the electroless plated layer and facing outward from the interface portion toward the side surface of the wiring board.

3. 3. The wiring board according to claim 1, wherein the electroless plated layer is formed by electroless copper plating, and the electrolytic plated layer is formed by electrolytic copper plating.

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